U.S. patent application number 10/712306 was filed with the patent office on 2004-11-18 for sealing device for linear guide apparatus.
This patent application is currently assigned to NSK LTD.. Invention is credited to Igarashi, Yutaka, Kato, Soichiro, Tsukada, Toru, Ueki, Fumio, Yabe, Toshikazu.
Application Number | 20040228551 10/712306 |
Document ID | / |
Family ID | 27323989 |
Filed Date | 2004-11-18 |
United States Patent
Application |
20040228551 |
Kind Code |
A1 |
Tsukada, Toru ; et
al. |
November 18, 2004 |
Sealing device for linear guide apparatus
Abstract
In a linear guide apparatus including an axially extending guide
rail, a slider engaged with the guide rail, and a plurality of
rolling elements loaded into the slider, the linear guide apparatus
further includes a sealing device fixed to the slider in slidable
contact with the guide rail for sealing a clearance existing
between the guide rail and the slider, in which the sealing device
includes: a lubricant-containing polymer member formed of a
synthetic resin containing a lubricant, and having a contact
portion contacting with the guide rail to surround the guide rail,
both wing portions, a connecting portion connecting the wing
portions to be C-shaped substantially, and a pair of first recesses
formed in the respective wing portions for fixing the
lubricant-containing polymer member to the slider; a first plate
member fitted to the lubricant-containing polymer member opposed to
the slider; and a pair of first cylindrical members inserted to the
respective first recesses.
Inventors: |
Tsukada, Toru; (Gunma,
JP) ; Igarashi, Yutaka; (Gunma, JP) ; Kato,
Soichiro; (Gunma, JP) ; Yabe, Toshikazu;
(Kanagawa, JP) ; Ueki, Fumio; (Kanagawa,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
NSK LTD.
|
Family ID: |
27323989 |
Appl. No.: |
10/712306 |
Filed: |
November 14, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10712306 |
Nov 14, 2003 |
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10263674 |
Oct 4, 2002 |
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6672764 |
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10263674 |
Oct 4, 2002 |
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09875272 |
Jun 7, 2001 |
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6550968 |
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09875272 |
Jun 7, 2001 |
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09371493 |
Aug 10, 1999 |
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6257765 |
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09371493 |
Aug 10, 1999 |
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08678765 |
Jul 11, 1996 |
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6019513 |
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Current U.S.
Class: |
384/45 ; 384/13;
384/15 |
Current CPC
Class: |
F16C 29/086 20130101;
F16C 33/6611 20130101; F16C 29/0642 20130101; F16C 33/6648
20130101; F16C 33/6622 20130101 |
Class at
Publication: |
384/045 ;
384/013; 384/015 |
International
Class: |
F16C 033/10; F16C
029/06; F16C 033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 1995 |
JP |
P. HEI. 7-174741 |
Jul 28, 1995 |
JP |
P. HEI. 7-193671 |
Aug 11, 1995 |
JP |
P. HEI. 7-206190 |
Claims
What is claimed is:
1. A linear guide apparatus comprising: an axially extending guide
rail having a first rolling groove on its outer surface; a slider
engaged with the guide rail and having a second rolling groove,
rolling element return grooves and curved grooves, the second
rolling groove, confronting the first rolling groove, the rolling
element return grooves being coupled to both end portions of the
second rolling groove through the curved grooves, respectively; a
plurality of rolling elements loaded into the slider to be made
circulatable through the second rolling groove, the curved grooves,
and the rolling element return grooves; and a sealing device fixed
to the slider in slidable contact with the guide rail for sealing a
clearance existing between the guide rail and the slider, the
sealing device comprising: a lubricant-containing polymer member
formed of a synthetic resin containing a lubricant, and having a
contact portion contacting with the guide rail to surround the
guide rail, both wing portions, and a connecting portion connecting
the wing portions to be C-shaped substantially; and a first plate
member fitted to the lubricant-containing polymer member, wherein
the lubricant-containing polymer member is interposed between the
slider and the first plate member.
2. The linear guide apparatus of claim 1, wherein the first plate
member comprises a side seal.
3. The linear guide apparatus of claim 1, wherein the sealing
device comprises a second plate member interposed between the
slider and the lubricant-containing polymer member.
4. The linear guide apparatus of claim 3, wherein at least one of
the first plate member and the second plate member comprises a side
seal.
5. The linear guide apparatus of claim 1, wherein the wing portions
and the connecting portion form an opening so that the
lubricant-containing polymer member is C-shaped substantially, and
the lubricant-containing polymer member is deformable so that the
opening shrinks.
6. The linear guide apparatus of claim 1, wherein the
lubricant-containing polymer member is deformable in a direction of
moving the wing portions toward each other to press the contact
portion against the guide rail.
7. The linear guide apparatus of claim 1, wherein the
lubricant-containing polymer member has an inner bottom face
arc-shaped in the connecting portion which elastically protrudes
toward the guide rail.
8. The linear guide apparatus of claim 1, wherein the sealing
device comprises a pair of first recesses formed in the respective
wing portions for fixing the lubricant-containing polymer member to
the slider and a pair of first cylindrical members inserted to the
respective first recesses.
9. The linear guide apparatus of claim 8, wherein the
lubricant-containing polymer member includes a second recess formed
in the connecting portion, and the sealing device comprises a
second cylindrical member inserted to the second recess, the second
cylindrical member having an outer diameter larger than an inner
diameter of the second recess.
10. The linear guide apparatus of claim 8, wherein each of the
first cylindrical members has a ring shape.
11. The linear guide apparatus of claim 1, wherein the
lubricant-containing polymer member has an elastic member to press
against the guide rail.
12. The linear guide apparatus of claim 11, wherein the elastic
member extends along the contact portion, the elastic member being
fitted closed to the contact portion.
13. The linear guide apparatus of claim 1, wherein the sealing
device comprises a second plate member interposed between the
slider and the lubricant-containing polymer member.
14. The linear guide apparatus of claim 8, wherein each of the
first cylindrical members has an axial length larger than a
thickness of the lubricant-containing polymer member.
15. The linear guide apparatus of claim 9, wherein the second
cylindrical member has an axial length larger than a thickness of
the lubricant-containing polymer member.
16. The linear guide apparatus of claim 1, wherein the
lubricant-containing polymer member is formed of polyolefinic
polymer containing the lubricant of 20 to 80% by weight.
17. The linear guide apparatus of claim 1, wherein the first plate
member is formed of nitrile rubber.
18. The linear guide apparatus of claim 1, wherein the
lubricant-containing polymer member comprises a plurality of seal
lips formed in the contact portion to contact the guide rail
slidingly, the seal lips comprising a plurality of cutout portions
arranged in a thickness direction of the sealing device.
19. A linear guide apparatus comprising: an axially extending guide
rail having a first rolling groove on its outer surface; a slider
engaged with the guide rail and having a second rolling groove,
rolling element return grooves and curved grooves, the second
rolling groove confronting the first rolling groove, the rolling
element return grooves being coupled to both end portions of the
second rolling groove through the curved grooves, respectively; a
plurality of rolling elements loaded into the slider to be made
circulatable through the second rolling groove, the curved grooves,
and the rolling element return grooves; and a sealing device fixed
to the slider in slidable contact with the guide rail for sealing a
clearance existing between the guide rail and the slider, the
sealing device comprising: a side seal directly or indirectly fixed
to the slider and having a seal lip contacting with the guide rail;
and a lubricant-containing polymer member formed of a synthetic
resin containing a lubricant and disposed closed to the seal
lip.
20. The linear guide apparatus of claim 1,9, wherein the
lubricant-containing polymer member includes a contact portion
contacting with the guide rail.
21. The linear guide apparatus of claim 19, wherein the side seal
is formed of a material cured with polyurethane rubber containing
grease.
22. The linear guide apparatus of claim 19, wherein the
lubricant-containing polymer member is formed of polyolefinic
polymer containing the lubricant of 20 to 80% by weight.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a linear guide apparatus,
and more particularly relates to a sealing device for a linear
guide apparatus which lubricant can be stably fed to the rolling
elements over a long period of time.
[0002] Further, the present invention relates to a linear guide
apparatus, and more particularly relates to a linear guide
apparatus, to the lip portion of the sealing device of which
lubricant can be automatically fed, so that the life of the sealing
device can be prolonged.
[0003] A first conventional example will be described as follows.
An example of the conventional linear guide apparatus, which is
commonly used, is shown in FIG. 37. This conventional linear guide
apparatus includes: a guide rail 1 extending in the axial
direction, on the outer surface of which a rolling element rolling
groove 3 is formed; and a slider 2 incorporated to the guide rail 1
in such a manner that the slider 2 strides the guide rail 1. The
slider 2 is composed of a slider body 2A and end caps 2B attached
to both ends of the slider body 2A. On inner side surfaces of both
wing portions 4 of the slider body 2A, there are provided rolling
element rolling grooves (not shown in the drawing) which are
opposed to the rolling element rolling groove 3 formed on the guide
rail 1. Also, in the slider body 2A, there are provided rolling
element returning paths (not shown) which penetrate thick portions
of the wing portions of the slider body 2A. On the other hands, the
end caps 2B have curved paths (not shown) which communicate the
rolling element rolling grooves of the slider body 2A with the
rolling element returning paths formed in parallel to the rolling
element rolling grooves. In this way, a circulation circuit of the
rolling elements is formed by the rolling element rolling grooves,
the rolling element returning paths and the curved paths formed on
both sides. For example, a large number of rolling elements
composed of steel balls are charged into the circulation circuit in
which the rolling elements are circulated.
[0004] The slider 2 incorporated to the guide rail 1 is smoothly
moved along the guide rail 1 when the rolling elements are rolling
in both rolling element grooves which are opposed to each other.
While the rolling elements are rolling in this way, they circulate
endlessly in the rolling element circulation passages formed in the
slider.
[0005] As a sealing device to seal an opening between the slider 2
and the guide rail 1 for the purpose of dust protection, as shown
in FIG. 38, there are provided side seals 5 on both ends (end faces
of the end caps 2B), and also there is provided an under seal 6 on
the lower surface of the slider 2. Conventionally, these seals are
made of rubber such as NBR (acrylonitrile butadiene rubber). In
this connection, reference numeral 7 in FIG. 37 is a grease
nipple.
[0006] A second conventional example of the linear guide apparatus
is disclosed in Unexamined Japanese Patent Publication No. Hei.
6-346919 previously proposed by the present applicant. A third
conventional example of the linear guide apparatus is disclosed in
Unexamined Japanese Patent Publication No. Hei. 7-35146 previously
proposed by the present applicant.
[0007] The second conventional example will be described as
follows. Between the outer surface of the guide rail and the inner
surface of the slider moving along the guide rail, there is
provided a seal device having a seal lip portion made of rubber or
synthetic resin containing lubricant. The seal lip portion comes
into contact with an outer surface of the guide rail and seals a
gap formed between the inner surface of the slider and the outer
surface of the guide rail. Since the seal lip portion of the seal
device is made of rubber or synthetic resin containing lubricant so
that the seal lip portion has a self-lubricating property, the
lubricant contained in the seal gradually oozes out and is
automatically fed to a frictional surface of the seal portion.
Therefore, the abrasion of the seal lip portion can be
suppressed.
[0008] The third conventional example will be described as follows.
At least a portion of the layer made of rubber or synthetic resin
and a portion of the layer made of rubber or synthetic resin
containing lubricant are overlapped and integrally joined. At
least, on the layer of rubber or synthetic resin containing
lubricant, there is formed a seal lip portion which comes into
contact with an outer surface of the guide rail so as to seal a gap
formed between the inner surface of the slider and the outer
surface of the guide rail. Since the seal lip portion also has a
self-lubricating property in this third conventional example,
lubricant Contained in the seal itself gradually oozes out and is
fed to a frictional surface of the seal, so that the abrasion of
the lip portion can be suppressed. Since the layers are overlapped
as described above in the third conventional example, it is
possible to provide the following advantages. When the number and
thickness of the overlapped layers are appropriately determined,
the mechanical strength of the seal lip portion can be arbitrarily
set in accordance with the use of the linear guide apparatus.
[0009] As shown in FIGS. 52 to 53B, the sealing device of the
second conventional example is described as follows. Lubricant is
made to ooze from a surface of the guide rail 1 by the action of
contact resistance of the seal 11. Accordingly, there is provided
no relief 10a as shown in FIG. 53A in the contact portion 11a shown
in FIG. 53B where the seal 11 comes into contact with the guide
rail 1, but an area of the portion where the seal 11 comes into
contact with the guide rail 1 is increased. Further, there is
formed a recessed groove 12 in the contact portion 11a where the
seal 11 comes into contact with the guide rail 1, so that the
portion 11a is divided into two portions. Then the thus divided
portions are contacted with the guide rail 1 by two steps.
Therefore, the intrusion of foreign objects can be prevented by the
contact of two steps better than the contact of one step. Further,
lubricant can be held by the recessed groove 12, so that the
sliding property of the seal 11 can be enhanced.
[0010] However, the above conventional linear guide apparatus has
the following disadvantages.
[0011] As the slider 2 runs along the guide rail 1, a quantity of
grease previously charged inside the slider 2 is decreased.
Therefore, the lubrication between the lip portion of the side seal
5 and the guide rail 1 becomes poor, and also the lubrication
between the lip portion of the under seal 6 and the guide rail 1
becomes poor. Due to the poor lubrication, the lip portions
gradually wears away. Due to the progress of abrasion, the sealing
property is deteriorated, and foreign objects such as cutting chips
enter the inside of the slider 2, which shortens the life of the
linear guide apparatus in some cases.
[0012] When the slider 2 runs and the rolling elements roll, grease
can be fed to the rolling element rolling groove 3 of the guide
rail 1 via the rolling elements. Accordingly, the abrasion is
relatively small in a portion of the lip which comes into contact
with the rolling element rolling groove 3. On the other hand, the
abrasion tends to increase in a portion of the lip which comes into
contact with an upper surface of the rail to which no grease is fed
because of poor lubrication. Due to the foregoing, the lip portion
wears away and damaged. In this way, the life of the linear guide
apparatus is shortened.
[0013] From this point of view, when the above second example and
the third one are adopted, the abrasion of the seal lip portion can
be suppressed since the seal lip portion has a self-lubricating
property. However, even in the above conventional examples, the
following problems may be encountered. A quantity of lubricant
oozing from rubber or synthetic resin containing lubricant is not
sufficient to lubricate the balls and rollers which guide the
movement of the slider of the linear guide apparatus, that is, it
is difficult to maintain smooth rolling motions of the rolling
elements such as balls and rollers.
[0014] In the sealing device containing lubricant of the above
second conventional example or the third one, the seal lip portion
is pressed against the guide rail only by the elasticity of the
seal itself. Accordingly, it is possible to provide a sufficiently
high pressing force as a seal, however, it is impossible to provide
a sufficiently high pressing force as a lubricant feed unit.
[0015] Further, a shape of each portion of the guide rail 1 with
which the seal 11 comes into contact, for example, a shape of the
ball rolling groove, the guide rail side surface or the upper
surface of the guide rail is complicated, and further the seal 11
is attached being a little displaced. Therefore, it is difficult
for the seal 11 to be positively contacted with each portion of the
guide rail 1. Accordingly, a sufficient quantity of lubricant can
not be provided and the dust protecting property is deteriorated.
As a result, the lubricant in the slider 2 is widely diffused.
SUMMARY OF THE INVENTION
[0016] The present invention has been accomplished to solve
problems caused in a conventional linear guide apparatus. An object
of the present invention is to provide a linear guide apparatus in
which the abrasion of a sealing device is reduced by directly
feeding lubricant to the lip portion or by feeding lubricant via
the guide rail, so that a high sealing property can be maintained
in the linear guide apparatus over a long period of time.
[0017] Another object of the present invention is to provide a
linear guide apparatus in which lubricant can be fed at all times
so as to maintain a smooth rolling motion of the rolling
elements.
[0018] Still another object of the present invention is to provide
a linear guide sealing device in which the seal can be positively
contacted with each portion while the seal precisely follows the
shape of each portion.
[0019] The objects of the invention are achieved by a linear guide
apparatus which includes: an axially extending guide rail having a
first rolling groove on its outer surface; a slider engaged with
the guide rail and having a second rolling groove, rolling element
return grooves and curved grooves, the second rolling groove
confronting the first rolling groove, the rolling element return
grooves being coupled to both end portions of the second rolling
groove through the curved grooves, respectively; a plurality of
rolling elements loaded into the slider to be made circulatable
through the second rolling groove, the curved grooves, and the
rolling element return grooves; and a sealing device fixed to the
slider in slidable contact with the guide rail for sealing a
clearance existing between the guide rail and the slider, the
sealing device comprising: a lubricant-containing polymer member
formed of a synthetic resin contfaining a lubricant, and having a
contact portion contacting with the guide rail to surround the
guide rail, both wing portions, a connecting portion connecting the
wing portions to be C-shaped substantially, and a first plate
member fitted to the lubricant-containing polymer member in which
the lubricant-containing polymer member is interposed between the
slider and the first plate member.
[0020] According to the invention, since a lubricant-containing
polymer member is arranged close to the lip portion of a side seal
which is provided in the sealing device, lubricant that has
gradually oozed from the lubricant-containing polymer member is
easily fed to the lip portion, so that the lip portion can be
stably lubricated over a long period of time.
[0021] In addition, since at least a portion of the inner
circumferential surface of the lubricant-containing polymer member
comes into contact with the outer circumferential surface of the
guide rail, the lip portion can be fed with lubricant via the guide
rail. Therefore, it is possible to feed lubricant to the lip
portion very stably. Accordingly, the abrasion of the lip portion
can be minimized, and the sealing property of the sealing device
can be maintained to be high over a long period of time.
[0022] Lubricant that has oozed from the lubricant-containing
polymer member is also fed to the rolling elements via the guide
rail. Accordingly, even when grease is exhausted from the apparatus
for some reasons, the lubricant that has oozed out from the
lubricant-containing polymer member functions as a lubricant of the
linear guide apparatus itself.
[0023] Especially when the lubricant-containing polymer member is
interposed between the slider end face and the side seal, the
leakage of grease from the device can be reduced. The reason is
described as follows. Conventionally, the lip portion of the
sealing device gets rolled up during a normal reciprocating motion
of the slider. At this time, grease leaks out from the device. On
the other hand, according to the invention, the
lubricant-containing polymer member is interposed between the
slider end face and the side seal. Therefore, the lip portion is
difficult to get rolled up, and the leakage of grease from the
device can be reduced. In the case where the side seal is composed
of a polyurethane rubber member containing grease which works as
lubricant, the abrasion of the lip portion of the sealing device
can be further reduced.
[0024] Further, according to the invention, when lubricant oozes
from the lubricant-containing member which strides the guide rail,
the lubricant-containing member shrinks by itself, so that a
distance between both wing portions of the lubricant-containing
member, which is arranged in a C-shape, is reduced, and further the
inside faces of both wing portions of the lubricant-containing
member, that is, the faces opposed to the side faces of the guide
rail, are pushed against the guide rail. Therefore, the
lubricant-containing member comes into contact with the guide rail
at all times. Due to the pushing force generated by the pushing
means, no gap is formed between the guide rail and the
lubricant-containing member irrespective of errors caused in the
manufacturing process. Therefore, the lubricant oozing from the
lubricant-containing member can be stably fed to the guide rail.
Particularly, the shape of the bottom surface of the C-shaped
lubricant-containing member is formed into a predetermined shape of
an arc. Therefore, even when the lubricant-containing member is
deformed by the pushing force of the pushing means so that both
wing portions are pressed against the guide rail, the shape of the
arc on the bottom surface is put into a horizontal condition.
Consequently, the lubricant-containing member stably comes into S
contact with the guide rail.
[0025] Moreover, according to the invention, a plurality of cutout
portions are formed in a portion of the seal lip which comes into
pressure contact with an outer surface of the guide rail.
Therefore, the seal lip in which a plurality of cutout portions are
formed can be contacted with the outer surface of the guide rail,
the shape of which is complicated. In this way, the seal lip can
easily follow the shape of the guide rail. Even when the lubricant
feed device is dislocated in the assembling process, the seal lip
having the cutout portions is deformed, so that the dislocation can
be absorbed, and no gap is formed between the seal lip portion and
the guide rail.
[0026] When a plurality of cutout portions are formed in the seal
lip portion, the contact area of the seal lip portion with the
guide rail can be increased, so that a quantity of lubricant oozing
from the seal lip portion can be increased. When the seal lip
portion is provided with a plurality of cutout portions, a space in
which the lubricant is held can be increased as compared with a
conventional arrangement. Therefore, the sliding property of the
seal lip portion can be enhanced. Further, the number of the seal
lip portions is increased as compared with a conventional
arrangement, so that the intrusion of dirt and dust from the
outside can be prevented, and the lubricant can be prevented from
diffusing to the outside.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view of the linear guide apparatus
of a first embodiment of the present invention;
[0028] FIG. 2 is a perspective view showing a condition in which
each member of a sealing device is attached to the end portion of
the linear guide apparatus;
[0029] FIGS. 3A and 3B are views showing an arrangement of the
lubricant-containing member of the second embodiment;
[0030] FIGS. 4A and 4B are views showing an arrangement of the
ring-shaped member;
[0031] FIGS. 5A and 5B are views showing an arrangement of the
ring-shaped member;
[0032] FIG. 6 is a side view of the lubricant-containing member in
a condition that the ring-shaped member is attached;
[0033] FIG. 7 is a front view of the lubricant-containing member
which strides a guide rail;
[0034] FIGS. 8A and 8B are schematic illustrations showing the mode
of operation;
[0035] FIG. 9 is a front view showing an arrangement of the
lubricant-containing member of a third embodiment of the present
invention;
[0036] FIG. 10 is a schematic illustration showing the mode of
operation of the third embodiment;
[0037] FIG. 11 is a perspective view showing an attaching condition
of each member of a sealing device of a fourth embodiment;
[0038] FIGS. 12A and 12B are views showing an arrangement of the
lubricant-containing member of the fourth embodiment;
[0039] FIGS. 13A and 13B are views showing an arrangement of the
elastic body of the fourth embodiment;
[0040] FIG. 14 is a schematic illustration of the mode of operation
of the fourth embodiment;
[0041] FIG. 15 is a schematic illustration of the mode of operation
of the fourth embodiment;
[0042] FIG. 16 is a front view of the lubricant-containing member
of the fourth embodiment, wherein the view shows a condition in
which the member strides the guide rail;
[0043] FIG. 17 is a side view of the lubricant-containing member of
the fourth embodiment, wherein a ring-shaped member is attached to
the member;
[0044] FIGS. 18A and 18B are views showing an arrangement of the
lubricant-containing member of a fifth embodiment of the present
invention;
[0045] FIGS. 19A and 19B are views showing an arrangement of the
lubricant-containing member of a sixth embodiment of the present
invention;
[0046] FIG. 20 is a view showing an arrangement of the elastic body
of the sixth embodiment;
[0047] FIGS. 21A and 21B are schematic illustrations showing an
assembling condition of the sixth embodiment;
[0048] FIG. 22 is a perspective view of the linear guide apparatus
of the sixth embodiment;
[0049] FIG. 23 is a front view of the lubricant-containing member
of a seventh embodiment of the present invention;
[0050] FIG. 24 is a view of the lubricant-containing member of an
eighth embodiment of the present invention;
[0051] FIGS. 25A and 25B are views showing an arrangement of the
elastic body of the eighth embodiment;
[0052] FIGS. 26A and 26B are schematic illustrations showing an
assembling condition of the eighth embodiment;
[0053] FIG. 27 is a front view of the lubricant-containing member
of a ninth embodiment of the present invention;
[0054] FIGS. 28A and 28B are views showing an arrangement of the
elastic body of the ninth embodiment;
[0055] FIGS. 29A and 29B are schematic illustrations showing an
assembling condition of the ninth embodiment;
[0056] FIGS. 30A and 30B are front views showing an arrangement of
a tenth embodiment of the present invention;
[0057] FIGS. 31A to 31D are perspective views showing an eleventh
embodiment of the present invention;
[0058] FIGS. 32A to 32C are perspective views showing variations of
the eleventh embodiment;
[0059] FIG. 33 is a front view showing an arrangement of a twelfth
embodiment of the present invention;
[0060] FIG. 34 is a perspective view of the lubricant-containing
polymer member of the first embodiment of the present
invention;
[0061] FIG. 35 is a perspective view of the sleeve inserted into
the lubricant-containing polymer member;
[0062] FIG. 36 is a perspective view showing an attaching condition
of each member of a sealing device of the linear guide apparatus
end portion;
[0063] FIG. 37 is a perspective view of the conventional linear
guide apparatus;
[0064] FIG. 38 is a perspective view of the lower surface side of
the linear guide apparatus shown in FIG. 37;
[0065] FIG. 39 is an overall perspective view of the side seal
composing a portion of the sealing device according to a thirteenth
embodiment of the present invention;
[0066] FIG. 40 is an enlarged cross-sectional view of the seal lip
of the side seal of the thirteenth embodiment;
[0067] FIG. 41 is a perspective view taken from the lower side of
the linear guide apparatus of the thirteenth embodiment;
[0068] FIG. 42 is an enlarged cross-sectional view of the seal lip
of the under seal of the thirteenth embodiment;
[0069] FIG. 43 is a schematic cross-sectional view for explaining a
variation of the side seal of the thirteenth embodiment;
[0070] FIG. 44 is a schematic perspective view for explaining
another variation of the side seal;
[0071] FIG. 45 is a partially enlarged view of the seal lip of the
side seal shown in FIG. 44;
[0072] FIG. 46 is a schematic perspective view for explaining
another variation of the side seal;
[0073] FIG. 47 is a partially enlarged view of the seal lip of the
side seal shown in FIG. 46;
[0074] FIG. 48 is a schematic perspective view for explaining
another variation of the side seal;
[0075] FIG. 49 is an enlarged cross-sectional view of the seal lip
portion of the side seal shown in FIG. 48;
[0076] FIG. 50 is a schematic perspective view for explaining
another variation of the side seal;
[0077] FIG. 51 is an enlarged cross-sectional view of the seal lip
portion of the side seal shown in FIG. 50;
[0078] FIG. 52 is an overall perspective view of another
conventional side seal; and
[0079] FIGS. 53A and 53B are enlarged cross-sectional views of two
types of the seal lip portion of the side seal shown in FIG.
52.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0080] Detailed explanations will be made below for the material of
the lubricant-containing member of the present invention.
[0081] In the case of a member made of rubber in which lubricant is
contained, for example, it is possible to use polyurethane rubber
that has been cured under the condition that it contains
grease.
[0082] Polyurethane rubber is a compound formed by the reaction of
polyisocyanate and active hydrogen compound. Examples of usable
polyisocyanate are: tolylenediisocyanate, hexamethylene
diisocyanate, and so forth.
[0083] Examples of usable active hydrogen compounds are:
hydrocarbon such as polybutadiene; polyether such as
polyoxypropylene; long link active hydrogen compound such as castor
oil, polyester and polycarbonate; polyhydroxy compound such as
water and ethylene glycol; and short link active hydrogen compound
such as aminoalcohol and polyamino compound.
[0084] An example of usable grease is common grease such as mineral
oil lithium soap grease.
[0085] Next, the lubricant-containing member in which lubricant is
contained in synthetic resin is formed as follows. Lubricant of
paraffin hydrocarbon oil such as poly-.alpha.-olefin oil, ether oil
such as naphthene hydrocarbon oil, mineral oil and dialkyl diphenyl
ether oil, and ester oil such as ester of phthalic acid is Bingly
mixed with synthetic resin or alternatively mixed with synthetic
resin in the form of mixed oil. In this case, the synthetic resin
is selected from a group of polyolefin resins having the same
chemical structure such as polyethylene, polypropylene,
polybutylene and polymethyl pentene. Material obtained in this way
is subjected to injection molding so as to mold the
lubricant-containing, member. Various addition agents such as an
antioxidant, rust preventive agent, antiabrasion agent, deforming
agent and extreme pressure agent may be previously added into the
lubricant.
[0086] In this case, a ratio of composition of the above
lubricant-containing member is as follows. With respect to the
total weight, polyolefin resin is 20 to 80% by weight, and
lubricant is 80 to 20% by weight. When the polyolefin resin is
smaller than 20% by weight, it is impossible to obtain a
predetermined level of hardness or mechanical strength. When
polyolefin resin exceeds 80% by weight, that is, lubricant is
smaller than 20% by weight, a quantity of lubricant to be fed is
decreased, so that the abrasion reducing effect of the lip portion
of the sealing device is deteriorated. Further, the polyolefin
resin is preferably 20 to 50% by weight and the lubricant is
preferably 80 to 50% by weight because the supply of the lubricant
increases so that it can further raises the abrasion reducing
effect of the lip portion of the sealing device.
[0087] Basic structures of the above group of synthetic resins are
the same and their average molecular weights are different from
each other. Values of the average molecular weights are in a range
from 1.times.10.sup.3 to 5.times.10.sup.6. Synthetic resin of
relatively low molecular weight, the average molecular weight of
which is 1.times.10.sup.3 to 1.times.10.sup.6, and synthetic resin
of extremely high molecular weight, the average molecular weight of
which is 1.times.10.sup.6 to 5.times.10.sup.6, are singly used, or
used being mixed with each other, if necessary.
[0088] In order to enhance the mechanical strength of the
lubricant-containing member of the present invention, the following
thermoplastic resins and thermosetting resin may be added to the
above polyolefin resins.
[0089] Examples of usable thermoplastic resins are: polyamide,
polycarbonate, polybutylene terephthalate, polyphenylene sulfide,
polyether sulfone, polyether etherketone, polyamideimide,
polystyrene, and ABS resin.
[0090] Examples of usable thermosetting resins are: unsaturated
polyester resin, urea formaldehyde resin, melamine resin, phenol
resin, polyimide resin, and epoxy resin.
[0091] These resins may be singly used. Alternatively, these resins
may be used being mixed with each other.
[0092] In order to disperse polyolefin resin and other resins more
uniformly, an appropriate compatibilizer may be added, if
necessary.
[0093] In order to enhance the mechanical strength, a filler may be
added. Examples of usable fillers are: calcium carbonate, magnesium
carbonate, inorganic wiskers such as potassium titanate wiskers and
aluminum borate wiskers, inorganic fiber such as glass fiber,
asbestos and metallic fiber, and cloth woven from these fibers.
Concerning inorganic compounds, carbon black, graphite powder,
carbon fiber, aramid fiber and polyester fiber may be added.
[0094] In order to prevent the deterioration of polyolefin resin
caused by heat, an age resistor such as
N,N'-diphenyl-P-phenylenediamine,
2,2'-methylenebis(4-ethyl-6-t-butyl phenol) may be added. In order
to prevent the deterioration of polyolefin resin caused by light,
an ultraviolet ray absorbing agent such as 2-hydroxy-4-n-octoxy
benzophenone and
2-(2'-hydroxy-3'-third-butyl-5'-methyl-phenyl)-5-chlorobenzotriazole
may be added.
[0095] In order to maintain the feeding capacity of lubricant, it
is preferable that a quantity of addition agent
(polyolefin+compound except for oil) is not more than 20% by the
weight of the overall material used for molding.
[0096] Next, referring to the accompanying drawings, a first
embodiment of the present invention will be explained below.
[0097] As shown in FIG. 1, which is a perspective view of the
linear guide apparatus of the first embodiment of the invention,
the linear guide apparatus includes: a guide rail 1 extending in
the axial direction, on the outer surface of which rolling element
rolling grooves 3A, 3B are formed; and a slider 2 incorporated to
the guide rail 1 in such a manner that the slider 2 strides the
guide rail 1.
[0098] The specific structure of the guide rail 1 is described as
follows. On the ridge line where an upper surface 1a of the guide
rail 1 crosses both side surfaces 1b, one rolling element rolling
groove 3A is formed, the section of which is a substantial 1/4 arc,
and the rolling element rolling groove 3A extends in the axial
direction of the guide rail 1. At an intermediate position on both
side surfaces of the guide rail 1, the other rolling element
rolling groove 3B is formed, the section of which is substantially
semicircular. At the bottom of the rolling element rolling groove
3B, there is formed a run-off-groove 3a for a retainer to prevent
the rolling elements from falling off when the slider 2 is not
incorporated to the guide rail 1.
[0099] An end cap 2B is a molding of synthetic resin manufactured
by injection molding, and the section of the end cap 2B is a
substantial C-shape. As shown in FIG. 2, which is a perspective
view showing an assembling condition of the end portion of the
slider 2, on the outside of both end caps 2B, there are provided a
sealing device 8 including a reinforcing plate 10 which is a
plate-shaped member, a lubricant-containing member 11, and a side
seal 12 which is a plate-shaped member, wherein they are arranged
in the above order from the side of the end cap 2B and fixed to the
end cap 2B being stacked to each other.
[0100] The reinforcing plate 10 is a C-shaped steel plate, the
outer configuration of which is the same as that of the end cap 2B.
In both wing portions 10A, 10B of the reinforcing plate 10, there
are formed through-holes 10a, 10b through which attaching screws
penetrate. In a connecting portion 10C that connects both wing
portions 10A and 10B, there is formed a through-hole 10c through
which a grease nipple is attached. In this connection, this
reinforcing plate 10 is not contacted with the guide rail 1.
[0101] The first embodiment of the present invention is shown in
FIGS. 34 to 36 in more detail. The sealing device 8 includes a side
seal 50 which is composed in such a manner that a sheet of
grease-containing polyurethane rubber is made to adhere onto a
C-shaped steel plate, the outer shape of which is substantially the
same as that of the end cap 2B, or alternatively a sheet of NBR
rubber is made to adhere onto a C-shaped steel plate. An inside
face of the C-shaped side seal 50 is formed into a shape so that
the side seal 50 can slidably come into contact with an upper face
1a and an outer side face 1b of the guide rail 1 so as to seal a
gap between the slider 2 and the guide rail 1. However, in order to
positively seal the gap between the slider 2 and the guide rail 1,
the size of the inner face of the side seal 50, which comes into
contact with the surface of the guide rail 1, is determined to be a
little smaller than the size of the surface of the guide rail 1 by
0.1 to 0.2 mm.
[0102] As shown in the perspective view of FIG. 36, the sealing
device 8 further includes a reinforcing plate 52 and a
lubricant-containing polymer member 51 which is interposed between
the side seal 50 and the reinforcing plate 52 and which is formed
into a substantial C-shape which is the same as the outer shape of
the end cap 2B. The inside face of the C-shape of the
lubricant-containing polymer member 51 is formed in accordance with
the sectional shape of the guide rail 1, and it is not contacted
with the upper face 1a and the outer side face 1b of the guide rail
1, or at least a portion of the inside face of the C-shape of the
lubricant-containing polymer member 41 is slidably contacted with
the upper face 1a and the outer side face 1b of the guide rail
1.
[0103] In the lubricant-containing polymer member 51, there are
formed through-holes 51a, 51b through which attaching screws
penetrate when the lubricant-containing polymer member 51 is
attached to the main body 2A, and there is also formed a
through-hole 51c through which the grease nipple 7 is attached.
Into the through-holes 51a, 51b and 51c, pipe-shaped sleeves 51A,
51B and 51C shown in FIG. 35 are inserted. The grease nipple 7
penetrates the inside of the sleeve 51C. In this connection, the
length L.sub.2 of these sleeves 51A, 51B, 51C is the same as the
thickness L.sub.1 of the lubricant-containing polymer member 51, or
alternatively the length L.sub.2 of these sleeves 51A, 51B, 51C is
made to be a little longer than the thickness L.sub.1 of the
lubricant-containing polymer member 51 (by about 0.2 mm).
[0104] Outer diameters of the sleeves 51A, 51B are made to be
larger than the diameters of the through-holes 50a, 50b of the side
seal 50 and the diameters of the through-holes 52a, 52b of the
reinforcing plate 52. Due to the foregoing arrangement, when the
lubricant-containing polymer member 51 is interposed between the
side seal 50 and the reinforcing plate 52 and fastened by the
attaching screws 53a, 53b, the pushing force is not given to the
lubricant-containing polymer member 51, so that the self-shrinking
action of the lubricant-containing polymer member 51 can not be
obstructed.
[0105] As shown in a perspective view of FIG. 36, the side seal 50,
the lubricant-containing polymer member 51 and the reinforcing
plate 52 of the sealing device 8 are integrally fixed to the main
body 2A together with the end cap 2B when the attaching screws 53a,
53b penetrate the through-holes 50a, 50bof the side seal 50, the
through-holes 51a, 51b of the lubricant-containing polymer member
51, and the through-holes 52a, 52b of the reinforcing plate 52. In
this connection, reference numeral 50c is a through-hole formed on
the side seal 50 through which the grease nipple 7 is attached, and
reference numeral 52c is a through-hole formed on the reinforcing
plate 52 through which the grease nipple 7 is attached.
[0106] Next, the mode of operation of the first embodiment will be
explained as follows.
[0107] In the first embodiment, a gap formed between the opposed
surfaces of the guide rail 1 and the slider 2 is sealed by the side
seal 50. Therefore, unless the side seal 50 wears away, it is
possible to perfectly prevent the entrance of dirt and dust into
the gap from the front and the rear of the slider 2.
[0108] When the slider 2 moves on the guide rail 1 fixed to the
mount, while the rolling elements B are rolling in the load rolling
element rolling path 21 (22), they move in the slider moving
direction at a speed lower than the moving speed of the slider and
make a U-turn at the curved path on one end side. After that, while
the rolling elements B are rolling in the rolling element return
path 23 (24) in the reverse direction, they make a reverse U-turn
in the curved path on the other end side. Then, the rolling
elements B return to the load rolling element rolling path 21 (22).
In this way, the rolling elements B circulate in the rolling
paths.
[0109] When the linear guide apparatus is driven as described
above, the lubricant-containing polymer member 51 is also moved
while it is contacted or not contacted with the guide rail 1.
Therefore, lubricant gradually oozes from the lubricant-containing
polymer member 51. Since the lubricant-containing polymer member 51
is arranged close to the lip portion of the side seal 50 (the inner
surface of the side seal 50 which comes into contact with the guide
rail 1), the lip portion of the side seal 50 is stably lubricated
by this oozing lubricant over a long period of time. In an
arrangement in which the lubricant-containing polymer member 51
comes into contact with the guide rail 1, lubricant can be fed to
the lip portion of the side seal 50 via the surface of the guide
rail 1. Accordingly, lubricant can be more stably fed to the lip
portion in this arrangement.
[0110] Due to the foregoing, the abrasion of the lip portion of the
side seal 50 can be minimized. Therefore, the sealing property of
the side seal 50 can be maintained over a long period of time, and
the entrance of dirt and dust into the main body 2A can be
prevented. As a result, the life of the linear guide apparatus can
be prolonged.
[0111] Further, the lubricant that has oozed from the
lubricant-containing polymer member 51 is automatically fed to the
rolling elements B, which are rolling in the rolling grooves 3, 13,
via the rolling grooves 3, 13. Due to the self-lubricity described
above, it is possible for the apparatus to be smoothly operated
over a long period of time. Accordingly, even if lubricant is not
fed to the slider 2 from the outside of the apparatus, operation
can be smoothly continued over a long period of time under the
condition of low resisting torque.
[0112] In an arrangement in which the lubricant-containing polymer
member 51 comes into contact with the guide rail 1, as the
lubricant oozes from the lubricant-containing polymer member 51,
the lubricant-containing polymer member 51 shrinks by itself. By
the shrinking force, the lubricant-containing polymer member 51
closely comes into contact with the surface of the guide rail 1 to
be sealed. Therefore, the lubricant-containing polymer member 51
performs both the sealing function and the lubricating
function.
[0113] When the side seal 50 is made of polyurethane rubber that
has been cured under the condition it contains grease, lubricant is
fed by the side seal 50 itself. Therefore, the abrasion of the lip
portion of the side seal 50 can be more reduced by the lubricant
fed by the side seal 50 itself.
[0114] Since the lubricant-containing polymer member 51 is
interposed between the end cap 2B and the side seal 50 via the
reinforcing plate 52, the lip portion of the sealing 50 seldom gets
rolled up during the reciprocating motion of the slider 2.
Accordingly, it is possible to prevent the leakage of grease from
the slider 2.
[0115] When the arrangement of the first embodiment is adopted, the
grease nipple attaching hole may be closed with a blank plug.
However, when necessary, this hole may be opened at an appropriate
time, to that lubricant such as grease can be fed into the
slider.
[0116] In the linear guide apparatus of the first embodiment, the
lubricant-containing polymer member 51 is fixed to the end face of
the end cap 2B under the condition that the lubricant-containing
polymer member 51 is interposed between the reinforcing plate 52
and the side seal 50. However, it should be noted that the present
invention is not limited to the first embodiment. For example, in
the same manner as that shown in FIG. 37, the side seal 50 is
directly attached to the end face of the end cap 2B, and the
lubricant-containing polymer member 51 may be fixed to the end face
of the end cap 2B, to which the side seal 50 is attached, under the
condition that the lubricant-containing polymer member 51 is
interposed between two pieces of reinforcing plates 52. Even in the
above arrangement, as long as the lubricant-containing polymer
member 51 is arranged close to the lip portion of the side seal 50,
the same effect as that of the first embodiment can be
provided.
[0117] The present inventors made an experiment to check the
abrasion of the side seal of the linear guide apparatus of the
first embodiment. The result of the experiment will be explained
below, referring to the comparative example.
[0118] First, the linear guide apparatus of the first embodiment of
the present invention, the arrangements of which are described in
Examples (1), (2) and (3), were manufactured. As a comparative
example, the linear guide apparatus, the arrangement of which is
described in Example (4), was manufactured.
EXAMPLE (1)
[0119] The side seal 50 was made of NBR rubber. The
lubricant-containing polymer member 51 was manufactured as follows.
That is, 70% by weight of paraffin mineral oil (FBK RO100
manufactured by Nippon Sekiyu Co.) to be used as lubricant was
contained in polyethylene composed of 21% by weight of low
molecular weight polyethylene (PZ50U manufactured by Mitsubishi
Yuka Co.) and 9% by weight of super high molecular weight
polyethylene (MIPELON XM220 manufactured by Mitsui Sekiyu Kagaku
Co.). The thus obtained material was subjected to an injection
molding machine and plasticized (melted). Then the plasticized
material was injected into a predetermined metallic mold and cooled
and solidified while it was being pressured. There was provided a
gap of 0 to 0.1 mm between the inner face of the
lubricant-containing polymer member 51 and the surface of the guide
rail 1. A portion of the inner face of the lubricant-containing
polymer member 51, the area of which was about 70% of the inner
face, was contacted with the surface of the guide rail 1.
EXAMPLE (2)
[0120] An arrangement of Example (2) is the same as that of Example
(1) except that the side seal 40 was made of grease-containing
polyurethane rubber.
[0121] The grease-containing polyurethane rubber was manufactured
as follows. Mixture (CORONATE T-6 manufactured by Nippon
Polyurethane Kogyo Co.) to be used as polyisocyanate in which
2,4-tolylenediisocyanate and 2,6-tolylenediisocyanate were mixed by
a mixing ratio 65:35, was reacted with polyesterpolyol (NIPPOLLAN
4032 manufactured by Nippon Polyurethane Kogyo Co.) to be used as
active hydrogen compound, so that compound was formed as a result
of reaction. Polyisocyanate, active hydrogen compound and grease
were mixed with each other so that the thus formed compound could
be mixed with mineral oil lithium soap grease (Alvania Grease No. 2
manufactured by Showa Shell Sekiyu K.K.) to be used as grease, by a
mixing ratio of 1:1. The thus obtained mixture was heated in an
appropriate metallic mold and cured so that it was integrated into
one body.
EXAMPLE (3)
[0122] The same side seal 50 and lubricant-containing polymer
member 51 as those of Example (1) were used. However, the
lubricant-containing polymer member 51 was not contacted with the
guide rail 1, wherein a gap 0.2 mm to 0.3 mm was formed between the
inner face of the lubricant-containing polymer member 51 and the
outer surface of the guide rail 1. In this connection, concerning a
linear guide apparatus in which the side seal 50 was directly
attached to the end face of the end cap 2B and in which the
lubricant-containing polymer member 51 interposed between two
reinforcing plates 52 was fixed to the end face of the cap 2B to
which the side seal 50 was attached, the following measurement was
conducted under the same condition as that of Example (3). As a
result of the measurement, the same result was obtained.
EXAMPLE (4)
[0123] The side seal 50 was made of NBR rubber, and the
lubricant-containing polymer member 51 was not used.
[0124] The apparatus described in Examples (1) to (4) were operated
in such a manner that the respective linear guide apparatus were
made to run by 5000 km, and then quantities of abrasion were
measured. By the measurement, the results shown on Table 1 were
obtained. In this connection, although the side seals 50 were
attached to both end portions of each linear guide apparatus, a
quantity of abrasion of one side seal 50 was measured.
1 TABLE 1 Quantity of Abrasion Linear Guide Apparatus (g/piece)
Example (1) 0.007 Example (2) 0.002 Example (3) 0.01 Comparative
Example (4) 0.20
[0125] As can be seen in the result of the experiment, according to
Examples (1), (2) and (3) of the present invention, a quantity of
abrasion of the side seal 50 can be remarkably reduced, and the
sealing property can be maintained over a long period of time.
[0126] Further, the present inventors made another experiment to
check an endurance of the linear guide apparatus operating in an
environment of being filled with wood cutting chips. In the
endurance experiment, the linear guide apparatus of the first
embodiment is filled up with Alvania Grease No. 2 mentioned above.
The endurance experiment was carried out in the environment of the
wood cutting chips piled up so that the linear guide apparatus was
entirely covered with the wood cutting chips. The result of the
endurance experiment will be explained below, referring to the
comparative example.
2TABLE 2 Composition of Relative lubricant-containing Linear
Running polymer member Guide Apparatus Life (% by weight) Seal
Comparative 1.0 none NBR rubber Example (4) Example (1) 2.5 LPE:
21, HPE: 9, LUB: 70 NBR rubber Example (A) 2.3 LPE: 41, HPE: 9,
LUB: 50 NBR rubber Example (B) 1.7 LPE: 61, HPE: 9, LUB: 30 NBR
rubber Comparative 1.1 LPE: 81, HPE: 9, LUB: 10 NBR rubber Example
(C) Comparative 0.9 LPE: 21, HPE: 9, LUB: 70 none Example (D)
[0127] In Table 2, Example (1) and Comparative Example (4) are the
same as examples shown in Table 1. Examples (A) and (B) as well as
Comparative Examples (C) and (D) were added for the endurance
experiment. The relative running life was represented by a ratio
that the running life of Comparative Example (4) was taken as 1.0.
Comparative Example and (D) used is a reinforcing plate with no
seal. In the column of Table 2 regarding the composition of the
lubricant-containing polymer member, "LPE" indicates low molecular
weight polyethylene (PZ50U manufactured by Mitsubishi Yuka Co.);
"HPE" indicates super high molecular weight polyethylene (MIPELON
XM220 manufactured by Mitsui Sekiyu Kagaku Co.); and "LUB"
indicates paraffin mineral oil (FBK RO100 manufactured by Nippon
Sekiyu Co.) to be used as lubricant.
[0128] As can be seen in the result of the endurance experiment,
when a quantity of lubricant is 50 to 80% by weight, the running
life extends remarkably. In contrast, when a quantity of lubricant
is less than 30% by weight, the effect of extending the running
life is small. Particularly, when a quantity of lubricant is 10% by
weight less than 20% by weight, the effect of extending the running
life is not almost developed.
[0129] Further, if the NBR rubber is not attached in the outside of
the lubricant-containing polymer member, the lubricant-containing
polymer member has a manufacturing limit of about 0 to 0.1 mm as a
gap relative to the guide rail. Accordingly, since the sealing
property is deteriorated, the wood cutting chips are prone to enter
to the interior of the linear guide apparatus, even compared with
an example of only a rubber seal attached to the end cap.
Therefore, the running life of the linear guide apparatus with no
NBR rubber is made short.
Second Embodiment
[0130] Next, the second embodiment of the present invention is
shown in FIGS. 1 to 8B. A shape of the side seal of the apparatus
of the second embodiment is different from the shape of the side
seal of the apparatus of the first embodiment, which is a main
different point. The side seal 12 of the second embodiment
includes: a C-shaped steel plate, the shape of which is the same as
the shape of the end cap 2B; and a piece of grease-containing
polyurethane rubber, the shape of which is similar to the shape of
the C-shaped steel plate, wherein the piece of grease-containing
polyurethane rubber is integrally attached to an outer surface of
the C-shaped steel plate.
[0131] There is provided a lip portion 13 of the side seal 12 which
comes into contact with the guide rail 1. An inside face of the lip
portion 13 of the side seal 12 coming into contact with the guide
rail 1 is formed into a shape so that the side seal 12 can slidably
come into contact with an upper face la and an outer side face 1b
of the guide rail 1 and so that a gap between the slider 2 and the
guide rail 1 can be sealed. More specifically, the lip portion 13
of the side seal 12 is formed into a shape so that the lip portion
13 can be slidably contacted with the rolling element rolling
grooves 3A, 3B and the run-off groove 3a. In this connection, in
both wing portions 12A, 12B of the side seal 12, there are formed
through-holes 12a, 12b through which attaching screws penetrate. In
a connecting portion 12C that connects both wing portions 12A and
12B, there is formed a through-hole 12cthrough which a grease
nipple is attached.
[0132] There is provided a lubricant-containing member 11 which is
interposed between the side seal 12 and the reinforcing plate 10.
This lubricant-containing member 11 is formed into a substantial
C-shape in accordance with the outer shape of the end cap 2B. The
inside face of the C-shaped lubricant-containing member 11 is not
tapered but flat. Accordingly, in the same manner as that of the
inner face of the lip portion 13, the inside face of the C-shaped
lubricant-containing member 11 can be contacted with an upper face
1a of the guide rail 1 and an outer side face 1b including the
rolling element rolling grooves 3A, 3B in accordance with the
sectional shape of the guide rail 1.
[0133] As shown in FIG. 3A which is a front view and FIG. 3B which
is a side view of the lubricant-containing member 11, in both wing
portions 11A and 11B of the lubricant-containing member 11, there
are formed through-holes 11a, 11b through which the attaching
screws penetrate. In a connecting portion 11C to connect both wing
portions 11A and 11B, there is formed a through-hole 11c through
which the grease nipple is attached. The through-holes 11a, 11b are
respectively open to the outside of the wing portions 11A, 11B. The
through-hole 11c is open to the upper face side of the connecting
portion 11C.
[0134] Dimensions of the recessed portion of this
lubricant-containing member 11 are determined so that the inner
face of the recessed portion can be slidably contacted with the
upper face 1a of the guide rail 1 and the outside face 1b including
the rolling element rolling grooves 3A, 3B. In portions on the
inner face of the recessed portion of the lubricant-containing
member 11 opposed to the rolling element rolling grooves 3A, 3B and
the run-off groove 3a of the guide rail 1, there are provided
protrusions 11f, 11g, 11d and 11e which are formed so that they can
slide on the inner faces of the grooves 3A, 3B and 3a. Further, The
shape of an inner bottom face 11h of the lubricant-containing
member 11, which slidably comes into contact with the upper face 1a
of the guide rail 1, is formed into an arc, the radius of curvature
of which is R, so that the center of the inner bottom face
protrudes from both end portions close to the wing portions 11A,
11B when the lubricant-containing member 11 is not given a force
from the outside.
[0135] Ring-shaped members 15A, 15B are inserted into the
respective through-holes 11a, 11b formed in both wing portions 11A,
11B of the lubricant-containing member 11. As shown in FIG. 4A
which is a front view of the ring-shaped members 15A, 15B and also
as shown in FIG. 4B which is a side view, the ring-shaped members
15A, 15B are short cylindrical members, and the outer diameters of
the ring-shaped members 15A, 15B are appropriate to insert them
into the through-holes 11a, 11b easily.
[0136] A ring-shaped member (or a solid cylindrical member) 16 is
inserted into the through-hole 11c formed in the connecting section
11C of the lubricant-containing member 11. As shown in FIG. 5A
which is a front view of the ring-shaped member 16 and also shown
in FIG. 5B which is a side view, this ring-shaped member 16 is a
short cylindrical member. However, the outer diameter D.sub.AR of
the ring-shaped member 16 is larger than the inner diameter D.sub.A
of the through-hole 11c. That is, when the ring-shaped member 16 is
inserted into the through-hole 11c, the through-hole 11c is
expanded.
[0137] Further, the length V of the ring-shaped members 15A, 15B is
a little longer than the thickness W of the lubricant-containing
member 11, for example, the length V of the ring-shaped members
15A, 15B is longer than the thickness W of the lubricant-containing
member 11 by about 0.2 mm. That is, when the ring-shaped members
15A, 15B and 16 are respectively inserted into the through-holes
11a to 11c, as shown in FIG. 6, end portions of the ring-shaped
members 15A, 15B and 16 protrude from the front side or the reverse
side of the lubricant-containing member 11.
[0138] The reinforcing plate 10, the lubricant-containing member 11
and the side seal 12 are integrally fixed to the main body 2A
together with the end cap 2B when the attaching screws 17A, 17B,
which penetrate the through-holes 2a, 2b of the end cap 2B and
screw to the main body 2A, penetrate the through-holes 12a, 12b of
the side seal 12, the ring-shaped members 15A, 15B inside the
through-holes 11a, 11b of the lubricant-containing member 11, and
the through-holes 10a, 10b of the reinforcing plate 10.
[0139] Next, the mode of operation of the second embodiment will be
explained below.
[0140] When the linear guide apparatus is driven, the
lubricant-containing member 11 is moved coming into contact with
the guide rail 1, and frictional heat is generated. Being
influenced by the frictional heat, lubricant gradually oozes from
the lubricant-containing member 11. After the lubricant has oozed
out, it is automatically fed to the rolling elements, which are
rolling in the rolling element rolling grooves 3A, 3B, via the
rolling element rolling grooves 3A, 3B. Due to the self-lubricity
described above, it is possible for the apparatus to be smoothly
operated over a long period of time. Accordingly, even if lubricant
is not fed to the slider 2 from the outside of the apparatus,
operation can be smoothly continued over a long period of time
under the condition of low resisting torque.
[0141] As described above, the shape of the inner face of the
recessed portion of the lubricant-containing member 11 is matched
with the transverse cross-sectional shape of the guide rail 1.
Therefore, as shown in FIG. 7, the lubricant-containing member 11
can be closely contacted with the upper face 1a and the side face
1b of the guide rail 1. As the lubricant oozes from the
lubricant-containing member 11, the lubricant-containing polymer
member 11 shrinks by itself. By the shrinking force, the
lubricant-containing polymer member 11 closely comes into contact
with the surface of the guide rail 1 to be sealed at all times.
Therefore, the lubricant-containing member 11 performs both the
sealing function and the lubricating function.
[0142] In the second embodiment, since the side seal 12 is used as
a plate member on the outside of the lubricant-containing member
11, the sealing property can be more enhanced.
[0143] Especially, in the second embodiment, since an upper face
side of the through-hole 11c formed in the connecting section 11C
of the lubricant-containing member 11 is cut away, the upper face
side of the through-hole 11c is open. Accordingly, as shown in FIG.
8A, the wing portions 11A and 11B can be easily expanded in the
transverse direction. Therefore, the lubricant-containing member 11
can be easily attached in the assembling process even if it is
arranged striding the guide rail 1.
[0144] Into the through-hole 11c of the lubricant-containing member
11, the ring-shaped member 16, the outer diameter of which is
larger than the inner diameter of the through-hole 11c, is inserted
to be used as a pushing means. Accordingly, when the
lubricant-containing member 11 strides the guide rail 1 as shown in
FIG. 8B, the ring-shaped member 16 expands the through-hole 11c in
the transverse direction. Therefore, a pushing force to push the
wing portions 11A, 11B against the guide rail 1 is generated by
this pushing means. Due to the foregoing, even if some
manufacturing errors are caused in the size of the
lubricant-containing member 11, or even if the lubricant-containing
member 11 wears away a little, it is possible to make the
lubricant-containing member 11 closely come into contact with the
surface of the guide rail 1 to be sealed at all times. In this
case, due to the structure of the through-hole 11c, the upper face
side of which is open, a force to expand the through-hole 11c by
the ring-shaped member 16 is effectively converted into a pushing
force to push the wing portions 11A, 11B against the guide rail 1.
Therefore, this structure of the through-hole 11c is very
advantageous.
[0145] The length V of the ring-shaped members 15A, 15B is a little
longer than the thickness W of the lubricant-containing member 11.
Therefore, end portions of the ring-shaped members 15A, 15b and 16
are protruded from the front side or the reverse side of the
lubricant-containing member 11. Since the attaching means for
attaching the lubricant-containing member 11 is composed in the
above manner, although the lubricant-containing member 11 is
interposed between the reinforcing plate 10 and the side seal 12,
the friction can be reduced. Due to the foregoing arrangement, the
lubricant-containing member 11 is smoothly deformed by the
self-shrinkage and the aforementioned pushing force in a direction
perpendicular to the axial direction of the guide rail 1.
Accordingly, it is possible to make the lubricant-containing member
11 closely come into contact with the guide rail 1 at all
times.
[0146] As described above, the inner bottom surface 11h of the
recessed portion of the lubricant-containing member 11 is formed
into an arc. Therefore, when the wing portions 11A, 11B of the
lubricant-containing member 11 are deformed being pushed against
the guide rail 1 by the self-shrinkage or the pushing force, the
inner bottom surface 11h is put into a substantially horizontal
condition, and the inner bottom surface 11h stably comes into
contact with the upper face 1a of the guide rail 1.
[0147] Since the lubricant-containing member 11 is interposed
between the reinforcing plate 10 and the side seal 12, it is easy
to increase the size of the lubricant-containing member 11 so that
a sufficient quantity of lubricant can be contained in the member
to continue a smooth rolling motion of the rolling elements over a
long period of time. Further, since the lubricant-containing member
11 is not made to adhere onto a steel plate or other members, it is
possible to reduce the cost of the lubricant-containing member 11
which is an article of consumption. Furthermore, it is possible to
save time and labor when the lubricant-containing member 11 is
replaced.
[0148] Since the lubricant-containing member 11 is interposed
between the reinforcing plate 10 and the side seal 12, it is
difficult for the lip portion 13, which is a portion of the side
seal 12 to be contacted with the guide rail 1, to get rolled up
when the slider 2 is reciprocated. Accordingly, the leakage of
grease from the slider 2 can be reduced.
[0149] After the lubricant has oozed from the lubricant-containing
member 11, it is fed to the lip portion 13 of the side seal 12
which comes into contact with the guide rail 1. Therefore, the
lubricant that has oozed from the lubricant-containing member 11 is
useful for the reduction of abrasion of the lip portion 13.
Especially, in the second embodiment, the lip portion 13 is made of
polyurethane rubber that has been cured under the condition that
grease is contained in it. Accordingly, the lubricant is fed by the
lip portion 13 itself, and the abrasion of the lip portion 13 can
be more reduced. Since the abrasion of the lip portion 13 can be
minimized, the sealing property of the lip portion 13 can be
maintained over a long period of time, and further it is possible
to prevent the intrusion of foreign objects into the main body 2A.
Accordingly, the life of the linear guide apparatus can be
prolonged.
[0150] According to the arrangement of the second embodiment,
lubricant is fed from the lubricant-containing member 11 to the
rolling elements at all times. Therefore, the grease nipple
attaching hole may be closed with a blank plug, however, this
grease nipple attaching hole may be opened when necessary so as to
feed lubricant into the slider.
[0151] In the second embodiment, the side seal 12 corresponds to
the plate member, the reinforcing plate 10 corresponds to another
plate member, and the ring-shaped member 16 corresponds to the
pushing means.
Third Embodiment
[0152] FIGS. 9 and 10 are views showing the third embodiment of the
present invention. In this connection, like reference characters
are used to indicate like parts in the views showing the second
embodiment and the third one, and the overlapping explanations are
omitted here.
[0153] The arrangement of the linear guide apparatus of the third
embodiment is the same as that of the first embodiment described
above, except that the shape of the lubricant-containing member 11
is changed.
[0154] Specifically, as shown in FIG. 9 which is a front view of
the lubricant-containing member 11, the shape of the
lubricant-containing member 11 is composed as follows. In the wing
portions 11A, 11B, there are formed cutout portions 20A, 20B which
continue to the through-holes 11a, 11b through which the attaching
screws penetrate, and the outside and the front end side of the
wing portions 11A, 11B are opened by the cutout portions 20A, 20B,
and the inner diameters of the ring-shaped members 15A, 15B, which
are inserted into the through-holes 11a, 11b, are made to be larger
than the outer diameters of the attaching screws 17A, 17B. Other
arrangements are the same as those of the second embodiment.
[0155] According to the above arrangement, as shown in FIG. 10
which is a front view of the lubricant-containing member 11
arranged in a condition of striding the guide rail 1, when the
attaching screws 17A, 17B are loosened, the ring-shaped members
15A, 15B can be moved outside. Therefore, only the
lubricant-containing member 11 can be removed from the linear guide
apparatus being pulled upward. In this way, the
lubricant-containing member 11 can be removed from the linear guide
apparatus. A new lubricant-containing member 11 can be inserted
into the linear guide apparatus from the upside without removing
the side seals and others from the main body 2A. The
lubricant-containing member 11 can be incorporated to the main body
in such a manner that the ring-shaped members 15A, 15B are pushed
into the through-holes 11a, 11b, and then the attaching screws 17A,
17B are fastened.
[0156] According to the arrangement of the third embodiment of the
present invention, the lubricant-containing member 11 from which
the lubricant has completely oozed can be easily replaced with a
new lubricant-containing member 11, which is called a cassette
system. Therefore, it is possible to feed the lubricant without
requiring much time and labor while the operator's hands are
maintained clean.
[0157] Other point of the third embodiment are the same as those of
the first embodiment described before.
Fourth Embodiment
[0158] FIGS. 11 to 17 are views showing the fourth embodiment of
the present invention. In this connection, like reference
characters are used to indicate like parts in the views showing the
first to third embodiments described before, and the overlapping
explanations are omitted here.
[0159] In the fourth embodiment, an arrangement to generate a
pushing force to push the wing portions 11A, 11B of the
lubricant-containing member 11 against the guide rail 1 is
different from that of the first and second embodiments described
before.
[0160] The specific arrangement is shown in FIGS. 11, 12A and 12B.
FIG. 11 is a perspective view showing an assembling condition of
the end portion of the slider 2, FIG. 12A is a front view of the
lubricant-containing member 11, and FIG. 12B is a side view of the
lubricant-containing member 11. As shown in these drawings, the
lubricant-containing member 11 is composed as follows. The
through-hole 11c of the lubricant-containing member 11 is omitted.
On the surface of the lubricant-containing member 11 on the front
side of the side seal 12, there is formed a continuous C-shaped
groove 30 which surrounds the recessed portion of the
lubricant-containing member 11. In the groove 30, there is provided
an elastic body 31 which acts as the pushing means shown in FIG.
13A which is a front view, and FIG. 13B which is a bottom view.
[0161] The elastic body 31 is an elastically deformable member made
of steel, synthetic resin or hard rubber. The shape of the elastic
body 31 is a substantial C-shape in accordance with the shape of
the groove 30. Under the condition that the elastic body 31 is not
given a force from the outside, the width of the opening side of
the C-shape is a little reduced.
[0162] Other points of the fourth embodiment are the same as those
of the first and second embodiments described before. However,
according to the fourth embodiment, the through-hole 11c of the
lubricant-containing member 11 is omitted, and the through-hole 10c
of the reinforcing plate 10 and the through-hole 12c of the side
seal 12 are also omitted, so that the grease nipple is not
provided. However, like the second embodiment described before, the
through-holes 10c, 11c, 12cmay be formed, and the grease nipple
attaching hole is closed with a blank plug in a normal operating
condition and opened when necessary so as to feed lubricant such as
grease into the slider.
[0163] According to the arrangement of the fourth embodiment, as
shown in FIG. 14, a pushing force to push the wing portions 11A,
11B of the lubricant-containing member 11 against the guide rail 1
is generated by an elastic force of the elastic body 31 provided in
the groove 30, and as shown in FIG. 15, when the
lubricant-containing member 11 is attached to the apparatus, the
wing portions 11A, 11B can be expanded in the transverse direction.
Accordingly, as shown in FIG. 16, it is possible to make the
lubricant-containing member 11 closely come into contact with the
guide rail 1 in a stable condition. Since the shape of the elastic
body 31 is determined in such a manner that an interval of the
front end portions is reduced when no load is given, even if the
lubricant-containing member 11 wears away a little, the inner
surfaces of the wing portions 11A, 11B can be more positively
pressed against the guide rail 1. As shown in FIG. 17, since the
ring-shaped members 15A, 15B protrude from the surface of the
lubricant-containing member 11 in the same manner as that of the
first embodiment described before, the lubricant-containing member
11 can be smoothly deformed.
[0164] In the above explanations, it can be seen that the same
effect as that of the first and second embodiments is provided by
the fourth embodiment.
[0165] Since the elastic body 31 to generate a pushing force is
arranged in such a manner that it surrounds the recess of the
lubricant-containing member 11 and the end portions of the elastic
body 31 are extended to positions close to the front end portions
of the wing portions 11A, 11B, the pushing force generated by the
elastic body can be more positively transmitted to the wing
portions 11A, 11B.
Fifth Embodiment
[0166] FIGS. 18A and 18B are views showing the fifth embodiment of
the present invention. FIG. 18A is a front view of the
lubricant-containing member 11. FIG. 18B is a cross-sectional view
taken on line XVIII-XVIII in FIG. 18A.
[0167] An arrangement of the fifth embodiment is essentially the
same as that of the fourth embodiment described above. A different
point is that a substantially rectangular cutout portion 11D, which
is open upward, is formed on an upper surface of the connecting
section 11C of the lubricant-containing member 11.
[0168] When the above cutout portion 11D is formed, the rigidity of
the connecting section 11C is lowered. Therefore, an elastic force
generated by the elastic body 31 is effectively converted into a
pushing force by which the wing portions 11A, 11B can be pressed
against the guide rail 1. Accordingly, it becomes possible to make
the lubricant-containing member 11 more positively come into
contact with the guide rail 1. Other points are the same as those
of the fourth embodiment described before.
Sixth Embodiment
[0169] FIGS. 19A to 22 are views showing the sixth embodiment of
the present invention. In this connection, like reference
characters are used to indicate like parts, and the overlapping
explanations are omitted here.
[0170] In the sixth embodiment, as shown in FIG. 19A which is a
front view of the lubricant-containing member 11 and FIG. 19B which
is a side view, there is formed a continuous outer circumferential
groove 33 on the outer surfaces of the wing portions 11A, 11B and
also on the upper surface of the connecting section 11C. In this
connection, at both ends of the outer circumferential groove 33,
there are formed recesses 33a which enter the inside of both wing
portions 11A, 11B.
[0171] An elastic body 34 shown in FIG. 20, which acts as the
pushing means, is engaged with the outer circumferential groove 33.
An arrangement of the elastic body 34 is the same as that of the
elastic body 31 shown in the fourth embodiment, except that the
size of the elastic body 34 is increased and protrusions 34a to be
engaged with the recesses 33a are formed at the front end
portions.
[0172] In the above arrangement, as shown in FIG. 21A, the elastic
body 34 pushes the wing portions 11A, 11B to the guide rail 1.
Therefore, the lubricant-containing member 11 can be made to stably
come into close contact with the guide rail 1. Since the
ring-shaped members 15A, 15B protrude from the surface of the
lubricant-containing member 11 as shown in FIG. 21B in the same
manner as that of the above second embodiment, the
lubricant-containing member 11 can be smoothly deformed.
Accordingly, the same effect as that of the fourth embodiment can
be provided by the sixth embodiment.
[0173] According to the arrangement of the sealing device 8 of the
sixth embodiment as shown in FIG. 22, only the elastic body 34 can
be removed without loosening or removing the attaching screws 17A,
17B. For this reason, it is possible to attach the elastic body 34
after all the parts have been attached. Therefore, this arrangement
can be variously used. For example, when it is unnecessary to press
the lubricant-containing member 11 against the guide rail 1, the
elastic body 34 is removed, and only when it becomes necessary to
press the lubricant-containing member 11 against the guide rail 1,
the elastic body 34 is attached. Alternatively, when it is required
that an intensity of the pushing force of the lubricant-containing
member 11 against the guide rail 1 is changed, the elastic body 34
is replaced with another one.
[0174] For example, this arrangement can be used as follows.
Immediately after the use of a new lubricant-containing member 11
is started, the lubricant-containing member 11 seldom wears away,
so that the lubricant-containing member 11 can be made to closely
come into contact with the guide rail 1. In this case, when the
elastic body 34 is attached to the lubricant-containing member 11,
too much lubricant oozes from the lubricant-containing member 11.
Therefore, the elastic body 34 is previously removed. When the
lubricant-containing member 11 wears away and it becomes difficult
to make the lubricant-containing member 11 closely come into
contact with the guide rail 1, the elastic body 34 is attached so
as to make the lubricant-containing member 11 closely come into
contact with the guide rail 1. In the event of progress of
abrasion, the elastic body 34 is replaced with a more elastic body.
In this way, a quantity of oozing lubricant can be stably
maintained at an appropriate value at all times.
[0175] In the sixth embodiment, there are formed recesses 33aat
both ends of the outer circumferential groove 33, and also there
are formed protrusions 34a engaging with these recesses 33a at both
ends of the elastic body 34. Accordingly, even if the elastic body
34 is set from the outside, there is no possibility that the
elastic body 34 easily falls off or slips in a direction in which
the elastic body 34 is disconnected from the apparatus.
Seventh Embodiment
[0176] FIG. 23 is a view showing the seventh embodiment of the
present invention. FIG. 23 is a front view of the
lubricant-containing member 11.
[0177] An arrangement of the seventh embodiment is essentially the
same as that of the fourth embodiment described before. A different
point is that a substantially rectangular cutout portion 11D, which
is open upward, is formed on an upper surface of the connecting
section 11C of the lubricant-containing member 11. Due to the
foregoing, the same effect as that of the fifth embodiment can be
provided by this embodiment, and other effects are the same as
those of the sixth embodiment.
Eighth Embodiment
[0178] FIGS. 24 to 26B are views showing the eighth embodiment of
the present invention. In this connection, like reference
characters are used to indicate like parts in the views showing
each embodiment described before, and the overlapping explanations
are omitted here.
[0179] In the eighth embodiment, as shown in FIG. 24 which is a
front view of the lubricant-containing member 11, in the connecting
section 11c of the lubricant-containing member 11, there is formed
a linear groove 37 extending in the width direction of the
lubricant-containing member 11. Into this groove 37, an elastic
body 38 is set which acts as the pushing means shown in FIG. 25A
which is a front view and FIG. 25B which is a bottom view.
[0180] The elastic body 38 is a thin prism-shaped elastic member
made of steel, synthetic resin or hard rubber, which is a little
curved. As shown in FIG. 26A which is a front view and FIG. 26B
which is a side view, the elastic body 38 is set into the groove 37
while the elastic body 38 is curved in a direction reverse to its
curved shape.
[0181] Even in this arrangement, the connecting section 11C of the
lubricant-containing member 11 is curved inside by an elastic
restoring force of the elastic body 38. Therefore, a pushing force
to push the wing portions 11A, 11B against the guide rail 1 is
generated. Accordingly, the same effect as that of the second
embodiment described before can be provided by the eighth
embodiment.
Ninth Embodiment
[0182] FIGS. 27 to 29B are views showing the ninth embodiment of
the present invention. In this connection, like reference
characters are used to indicate like parts in the views showing the
embodiments described before, and the overlapping explanations are
omitted here.
[0183] In the ninth embodiment, as shown in FIG. 27 which is a
front view of the lubricant-containing member 11, in the connecting
section 11c of the lubricant-containing member 11, there is formed
a rectangular through-hole 39 which is long in the transverse
direction. In this connection, on the upper side of the
lubricant-containing member 11, there is formed a cutout portion
11E through which the through-hole 39 communicates with the
outside.
[0184] As shown in FIG. 28A which is a front view and FIG. 28B
which is a side view, a coil spring 40, which acts as the pushing
means, is accommodated in the through-hole 39 under the condition
that its expanding direction is aligned in the transverse direction
and it is compressed as shown in FIG. 29A which is a front view and
FIG. 29B which is a partially cutaway side view.
[0185] According to this arrangement, the rigidity of the
connecting section 11C in the transverse direction is reduced by
the action of the cutout 11E, and the connecting section 11C of the
lubricant-containing member 11 is expanded in the transverse
direction by an elastic restoring force of the coil spring 40. As a
result, a pushing force to push the wing portions 11A, 11B to the
guide rail 1 is generated. Therefore, the same effect as that of
the second embodiment described before can be provided by the ninth
embodiment.
Tenth Embodiment
[0186] FIGS. 30A to 30B are views showing the tenth embodiment of
the present invention. FIG. 30A is a front view, and FIG. 30B is a
partially cutaway side view. In this connection, like reference
characters are used to indicate like parts in the views showing the
embodiments described before, and the overlapping explanations are
omitted here.
[0187] The tenth embodiment is arranged as follows. In the wing
portions 11A, 11B of the lubricant-containing member 11, there are
formed slits 41A, 41B extending in the upward and downward
direction, and ends of the slits 41A, 41B are open to the front end
sides of the wing portions 11A, 11B. In the intermediate portions
of these slits 41A, 41B, there are formed rectangular through-holes
42A, 42B which are long in the transverse direction. In the
through-holes 42A, 42B, there are provided coil springs 43A, 43B,
which act as pushing means, the expanding direction of which is
aligned in the transverse direction, wherein the coil springs 43A,
43B are set in the through-holes 42A, 42B being a little
compressed.
[0188] According to the above arrangement, the rigidity of the
connecting section 11C in the transverse direction is reduced by
the action of the slits 41A, 41B, and elastic restoring forces of
the coil springs 43A, 43B are used as pushing forces to press the
wing portions 11A, 11b against the guide rail 1. Accordingly, the
same effect as that of the second embodiment can be provided by the
tenth embodiment.
Eleventh Embodiment
[0189] FIGS. 31A to 31D are views showing the eleventh embodiment
of the present invention. FIGS. 31A to 31D are perspective views
showing variations of the ring-shaped member 16 to be set in the
through-hole 11c of the lubricant-containing member 11. In this
connection, the arrangement of the eleventh embodiment is the same
as that of the second embodiment except for the structure of the
ring-shaped member 16.
[0190] In the eleventh embodiment, the ring-shaped member 16, which
acts as the pushing means, is made of deformable material such as
metal or high polymer (plastics and rubber). On the outer
circumferential surface of the ring-shaped member 16, there are
formed slits 16a extending in the axial direction. In the same
manner as that of each embodiment described before, the inner
diameter of the through-hole 11c is made to be a little smaller
than the outer diameter of the ring-shaped member 16, so that the
ring-shaped member 16 can be inserted into the through-hole 11c
under the condition that the diameter of the ring-shaped member 16
is a little reduced. Since the slits 16a are formed in the eleventh
embodiment, the ring-shaped member 16 can be more smoothly,
elastically deformed in the direction in which the diameter of the
ring-shaped member 16 is reduced. Due to the foregoing, an
expanding action by which the through-hole 11c is expanded can be
stably provided by the ring-shaped member 16 over a long period of
time. Accordingly, the wing portions 11A, 11B can be stably pressed
against the guide rail 1 over a long period of time, and the same
effect as that of the second embodiment can be more positively
provided.
[0191] In this connection, the diameter expanding action of the
ring-shaped member 16 engaged with the through-hole 11c is
determined by the size and number of the slits 16a formed in the
ring-shaped member 16 and also determined by the wall thickness and
material of the ring-shaped member 16. A pushing force to push the
wing portions 11A, 11B against the guide rail 1 and a permissible
abrasion loss of the lubricant-containing member 11 are determined
by the deformation characteristic of the ring-shaped member 16.
Accordingly, it is necessary to appropriately determine the above
factors by the size and specification of the linear guide apparatus
to be used and the rigidity of the lubricant-containing member 11.
Consequently, the number of the slits 16a is not limited to the
specific embodiments shown in FIGS. 31A to 31D, but it can be
determined arbitrarily.
[0192] FIGS. 32A to 32C are views showing variations of the
eleventh embodiment. In the variations, instead of the ring-shaped
member 16, a solid columnar member 16A is used as a pushing means,
which is engaged in the through-hole 11c, wherein slits 16b are
formed in the columnar member 16A so that the diameter can be
expanded and contracted. Even when this columnar member 16A is
used, the same effect as that of the ring-shaped members 16 shown
in FIGS. 31A to 31D can be provided. In this connection, the
diameter expanding action of this columnar member 16 is determined
by the material and the size and number of the slits 16b.
Accordingly, in the same manner as that of the ring-shaped member
16, it is necessary to appropriately determine the above factors by
the size and specification of the linear guide apparatus to be used
and the rigidity of the lubricant-containing member 11.
Consequently, the number of the slits 16b is not limited to the
specific embodiments shown in FIGS. 32A to 32C, but it can be
determined arbitrarily.
Twelfth Embodiment
[0193] FIG. 33 is a view showing the twelfth embodiment of the
present invention. FIG. 33 is a front view of the
lubricant-containing member 11 when it is arranged striding the
guide rail 1. In this connection, like reference characters are
used to indicate like parts in the views showing the embodiments
described before, and the overlapping explanations are omitted
here.
[0194] In the twelfth embodiment, there are formed two
through-holes 11c at positions in the connecting sections 11C of
the lubricant-containing member 11 close to both wing portions 11A,
11B. The ring-shaped member 16 having the slits 16a shown in the
eleventh embodiment is inserted into each through-hole 11c.
[0195] In the above arrangement in which a plurality of
through-holes 11c and ring-shaped members 16 are provided, the
connecting section 11C of the lubricant-containing member 11 is
curved by a force to expand the diameter of each ring-shaped member
16. Therefore, a pushing force to push the wing portions 11A, 11B
against the guide rail 1 is generated. Accordingly, the same effect
as that of the second embodiment can be provided. In this
connection, the number of the through-holes 11c may be not less
than 3, and instead of the ring-shaped member 16, the columnar
members 16A shown in FIG. 32 may be inserted into a plurality of
through-holes 11c.
[0196] In the twelfth embodiment, explanations are made for a case
in which the lip portion 13 is formed from rubber containing
lubricant. However, since lubricant is fed from the
lubricant-containing member 11 to the lip portion 13, the lip
portion 13 may be made of NBR (acrylonitrile butadiene rubber) not
containing lubricant.
[0197] In each embodiment described before, the reinforcing plate
10 may be omitted, and the lubricant-containing member 11 may be
interposed between the end cap 2B and side seal 12. Since the
lubricant-containing member 11 substantially functions as a sealing
device, instead of the side seal 12, a steel plate like the
reinforcing plate 10 may be arranged as a reinforcing plate or a
protector. Under certain circumstances, instead of the reinforcing
plate 10, the side seal 12 may be interposed between the
lubricant-containing member 11 and the end cap 2B.
[0198] In each embodiment described before, the length V of the
ring-shaped members 15A, 15B, 16 is determined to be longer than
the thickness W of the lubricant-containing member 11. However, the
length V may be the same as the thickness W, or the length V may be
a little shorter the thickness W. The essential point to determine
the length V and the thickness W is described as follows. A
relation between the length V and the thickness W must be
maintained so that a deformation of the lubricant-containing member
11 in a direction perpendicular to the axial direction of the guide
rail 1 can not be obstructed when the lubricant-containing member
11 is fixed by fastening the attaching screws 17A, 17B.
[0199] The linear guide apparatus to which the present invention is
applied is not limited to the apparatus of the embodiments
described above. For example, the present invention can be applied
to a linear guide apparatus in which two or more rolling element
rolling grooves are formed on one side, or the rolling elements are
not balls but rollers.
[0200] As explained above, according to the invention, lubricant
can be very stably fed to the lip portion, so that the abrasion of
the lip portion can be minimized, and the sealing property of the
sealing device can be maintained at a high level over a long period
of time. Therefore, the intrusion of foreign object into the linear
guide apparatus can be suppressed and the life of the linear guide
apparatus can be prolonged.
[0201] Further, the lubricant gradually oozing from the
lubricant-containing member can be fed to the rolling elements via
the guide rail. Accordingly, the rolling elements can be smoothly
rolled. In this case, when the side seal is used as a plate member,
the abrasion of a contact surface of the side seal with the guide
rail can be reduced by the action of lubricant fed from the
lubricant-containing member. Therefore, the intrusion of foreign
objects into the rolling element rolling groove can be prevented,
and the life of the linear guide apparatus can be more
prolonged.
[0202] Moreover, it is possible to make the lubricant-containing
member come into contact with the guide rail at all times.
Therefore, the lubricant that has oozed from the
lubricant-containing member can be stably fed to the rolling
elements via the guide rail. As a result, the rolling elements can
be more smoothly rolled.
[0203] Still further, the lubricant-containing member can be made
to stably come into contact with the guide rail. Therefore, the
lubricant can be more stably fed to the rolling elements via the
guide rail.
Thirteenth Embodiment
[0204] The thirteenth embodiment of the present invention is shown
in FIGS. 39 to 42.
[0205] The under seal 21 is composed of an under seal reinforcing
plate 22 and an under seal body 23 made of lubricant-containing
rubber or synthetic resin which adheres onto the under seal
reinforcing plate 22. The under seal reinforcing plate 22 is made
of a rectangular steel plate, the length of which is substantially
the same as that of the slider 2, and the width of which is a
little larger than the width of the lower end face 24 of the slider
body 2A. An inner side edge of the under seal reinforcing plate 22
protrudes a little from an end of the lower end face 24 of the
slider body 2A. The seal body 23 is made of lubricant-containing
synthetic rubber or synthetic resin. The seal body 23 is made to
adhere onto the under seal reinforcing plate 22, which is a
rectangular plate, by adhesion or baking while the seal body 23 is
let to come near the inner edge side of the under seal reinforcing
plate 22. At an end edge of the seal body 23, there is provided a
seal lip L.sub.1 which comes into contact with the side 1b of the
guide rail 1. In this way, the seal lip portion is composed. 5 As
shown in FIG. 42, in a portion of the seal lip L.sub.1 which comes
into contact with the side surface 1b of the guide rail 1, there
are provided three cutout portions 25 extending in the longitudinal
direction of the seal body 23, wherein these cutout portions 25 are
arranged in the thickness direction of the seal body 23. Due to the
foregoing arrangement, the seal lip L.sub.1 is divided into four
pieces.
[0206] As shown in FIG. 39, the side seal 61 is composed in such a
manner that a lubricant-containing seal body 63 made of the same
material as that of the seal body 23 is made to adhere by adhesion
or baking onto an outer surface of the side seal reinforcing plate
62 made of a thin C-shaped steel plate, the shape of which is
substantially the same as that of the end cap 2B. In the C-shaped
seal body 63, on both side surfaces opposed to each other, there
are provided groove sliding protrusions 64a, 64b which are
respectively engaged with ball rolling grooves 3 of the guide rail
1, the number of which is two with respect to one side of the guide
rail 1. The seal lip L.sub.2 is formed on an inner edge of the seal
body 63 which comes into contact with the outer surface of the
guide rail 1. On the surface of this side seal 61, there is formed
one grease nipple attaching hole 66 in conjunction with a plurality
of attaching holes 65 through which the side seal 61 is attached to
the end cap 2B.
[0207] In a portion of the seal lip L.sub.2 which comes into
contact with the ball rolling groove 3, that is, in a portion of
the groove sliding protrusion 64, as shown in FIGS. 40 and 41,
there are formed three cutout portions 66 in the thickness
direction of the seal body 63. By the above cutout portions 66, the
seal lip L.sub.2 is divided into 4 pieces.
[0208] Next, the action will be explained as follows.
[0209] The under seal 21 is attached as follows.
[0210] The slider 2 is previously assembled by attaching the end
caps 2B to both end portions of the slider body 2A. The under seal
21 is fixed in such a manner that both end portions of the under
seal 21 in the longitudinal direction are engaged with attaching
grooves 26 formed on the lower surface of the front and rear end
cap 2B while the front end of the seal lip L.sub.1 is set inside.
The seal body 23 composing the seal lip portion of the under seal
21 allows the seal lip L.sub.1, which protrudes inside a little
from the side edge of the lower end face 24 of the slider body 2A,
to come into contact with the side surface 1b of the guide rail
1.
[0211] On the other hand, the side seals 61 are respectively
attached onto both end faces of the slider 2 when the screws 67
inserted into the attaching holes 65 are engaged with the screw
holes (not shown) formed in the end caps 2B. Concerning the seal
body 63 composing the seal lip portion of the side seal 61, the
seal lips L.sub.2 protruding to the inner edge respectively come
into contact with the side surface 1b of the guide rail 1, the
groove surface of the ball rolling groove 3, and the upper surface
1a of the guide rail 1.
[0212] In this way, by the under seal 21, a lower opening of the
gap between the guide rail 1 and the slider 2 can be sealed.
Further, by the side seal 61, front and rear openings of the gap
between the guide rail 1 and the slider 2 can be sealed.
Accordingly, the intrusion of dirt and dust from the front, the
rear and the lower portion of the slider 2 can be perfectly
blocked.
[0213] Further, the self-lubricity is provided to the sliding
surfaces of the under seal 21 and the side seal 61 by the
lubricant-containing seal bodies 23, 63. Therefore, the sliding
resistance of the contact seal is very low, and the abrasion seldom
occurs.
[0214] Even when this linear guide is used in an environment in
which dirt and dust such as chips of wood and chips of casting are
scattered, and even when a portion of the lubricant is absorbed by
the dirt and dust, lubricant is fed from the lubricant-containing
seal bodies 23, 63 at all times. Accordingly, there is no
possibility of defective lubrication.
[0215] Further, a plurality of cutout portions are formed in the
contact portion of the seal lip L.sub.1 which comes into contact
with the side 1b of the guide rail 1, and also a plurality of
cutout portions are formed in the contact portion of the seal lip
L.sub.2 which comes into contact with the upper face and the side
of the guide rail 1. By these cutout portions, both seal lips
L.sub.1 and L.sub.2 are respectively divided into 4 pieces.
Therefore, either of the pieces of the divided seal lip L.sub.1
(L.sub.2) is contacted with the outer surface of the guide rail 1,
the shape of which is complicated. In this way, the seal lip
L.sub.1 (L.sub.2) can easily follow the shape of the guide rail 1.
Even if the under rail 21 or the side rail 61 is dislocated a
little, the dislocation can be absorbed by the deformation of the
divided portions.
[0216] Moreover, the seal lips L.sub.1 and L.sub.2 are respectively
divided into 4 pieces. Therefore, the contact area of the seal lip
of the thirtieth embodiment can be more increased than that of the
seal lip of the conventional apparatus in which the seal lip is
divided into 2 pieces. As a result, quantities of lubricant oozing
from seal lips L.sub.1 and L.sub.2 can be increased. Further, since
the numbers of the seal lips L.sub.1 and L.sub.2 are increased, the
dust protecting function of the sealing device can be more
enhanced, and the lubricant in the sealing device is prevented from
diffusing outside.
[0217] Since three cutout portions are formed in each of the seal
lips L.sub.1 and L.sub.2, it is possible to increase the lubricant
holding space compared with the conventional apparatus in which one
groove is formed in the seal lip. As a result, the-sliding property
of the seal lips L.sub.1 and L.sub.2 can be enhanced.
[0218] In this connection, each seal lip L.sub.1, L.sub.2 is
provided with three cutout portions and divided into four pieces.
However, it should be noted that the present invention is not
limited to the above specific embodiment. For example, each seal
lip L.sub.1, L.sub.2 may be provided with two or not less than four
cutout portions and divided into three or not less than five
pieces.
[0219] Only the under seal on one side is shown in FIG. 39.
However, the under seals can be attached onto the lower end faces
24 on both sides of the slider body 2A. The under seal 21 is not
necessarily attached by the engagement system, but the under seal
21 may be attached by rivets or screws. The essential point is that
the sealing device of the present invention is not influenced by
the attaching structure of the under seal 21.
[0220] Several variations of the side seal are shown in FIGS. 43 to
51.
[0221] The side seal shown in FIG. 43 is arranged as follows. In
the same manner as that of the thirtieth embodiment, three cutout
portions 66a are formed in the seal lip L.sub.2, so that the seal
lip L.sub.2 is divided into four pieces, and both outside pieces of
the divided seal lip L.sub.2 are made to be longer than other
pieces. Due to the above arrangement, when the divided seal lip
L.sub.2 are made to come into contact with the guide rail 1, both
outside seal lips L.sub.2 are greatly extended outside, so that the
contact area can be increased. As a result, a quantity of lubricant
oozing from the seal lip can be more increased, and the lubricant
holding capacity of the seal lip can be more enhanced.
[0222] The side seal shown in FIGS. 44 and 45 are arranged as
follows. Checker-shaped cutout portions 66b are formed in the seal
lip L.sub.2. Therefore, the seal lip L.sub.2 is divided into a
large number of pieces by the checker-shaped cutout portions 66b.
Due to the foregoing arrangement, the number and the contact area
of the pieces of the divided seal lip L.sub.2 can be more
increased.
[0223] Cutout portions 66 formed in the side seals shown in FIGS.
46 to 49 are composed of not only simple straight lines but also
curves. By the combination of straight lines and curves, zigzag
cutout portions are formed. The side seal shown in FIGS. 50 and 51
is arranged as follows. When the seal lip portions L.sub.2 of the
side seal comes into contact with the guide rail 1, the cutout
portion 66 is divided into two (a plural number). This arrangement
is effective when the rigidity of the lip portion L.sub.2 is
required by increasing the width of its central portion.
[0224] As long as the slider is attached to the guide rail in such
a manner that the slider strides the guide rail, the linear guide
apparatus of the present invention is not limited to the specific
type. For example, in the embodiments described above, the number
of the ball rolling grooves 3 on one side is two, however, it is
possible to apply the present invention to an apparatus, the number
of the ball rolling grooves on one side of which is one or not less
than three. In this case, of course, it is possible to form the
sliding protrusions 64a, 64b of the side seal 61 in accordance with
the ball rolling groove 3.
[0225] In the embodiments described above, balls are used as the
rolling elements. However, it should be noted that the present
invention can be applied to an apparatus in which rollers are used
as the rolling elements.
[0226] A direction of the cutout portions formed in the seal lips
L.sub.1, L.sub.2 is not particularly limited. For example, the
cutout portions may be formed in an arbitrary direction such as a
direction oblique with respect to the axial direction of the guide
rail.
[0227] In the embodiments described above, the cutout portions are
formed on the overall inner circumferential wall of the side seal.
However, the present invention is not limited to the specific
embodiment. When necessary, the cutout portions may be formed only
in a portion of the ball rolling groove 3 or on an upper surface of
the guide rail 1. In this way, the cutout portions may be formed
only in a portion of the side rail.
[0228] In the embodiments described above, the main purpose of the
side seal is to accomplish the sealing function. However, it is
possible to adopt the following arrangement. In the slider, there
is provided a conventional side seal to which a piece of nitrile
rubber or urethane rubber is attached by melting. Different from
the above side seal, there is provided in series a sealing device
of the present invention. This sealing device may be used as a
lubricant feed device to feed lubricant to the seal lip portion and
the rolling elements of the conventional side seal.
[0229] There are formed a plurality of cutout portions in a portion
of the seal lip which comes into pressure contact with an outer
surface of the guide rail. Accordingly, either of the divided
portions of the seal lip comes into contact with an outer surface
of the guide rail, the shape of which is complicated. Therefore,
the seal lip easily follows the complicated shape of the guide
rail.
[0230] Further, there are provided a plurality of cutout portions
in the seal lip portion. Accordingly, compared with the
conventional sealing device in which one groove is formed in the
seal lip portion, the contact area of the seal lip which comes into
contact with the guide rail can be increased. As a result, it is
possible to increase a quantity of lubricant oozing from the seal
lip portion. Moreover, the number of the pieces of the divided seal
lip can be increased more than the number of the pieces of the
conventional seal lips. Accordingly, the dust protecting function
of the sealing device can be more enhanced, and the lubricant in
the sealing device is prevented from diffusing outside.
[0231] Since a plurality of cutout portions are formed in the seal
lip, it is possible to increase the lubricant holding space
compared with the conventional sealing device in which one groove
is formed in the seal lip. As a result, the sliding 5 property of
the seal lip can be enhanced.
* * * * *