U.S. patent application number 15/117293 was filed with the patent office on 2016-12-01 for shaft holding sleeve, shaft diameter enlarging apparatus and jig for shaft diameter enlarging apparatus.
The applicant listed for this patent is NETUREN CO., LTD.. Invention is credited to Takashi IKEDA, Fumiaki IKUTA, Yoshitaka KUWAHARA, Kazuki MORI, Mitsuhiro OKAMOTO.
Application Number | 20160346828 15/117293 |
Document ID | / |
Family ID | 52814167 |
Filed Date | 2016-12-01 |
United States Patent
Application |
20160346828 |
Kind Code |
A1 |
KUWAHARA; Yoshitaka ; et
al. |
December 1, 2016 |
SHAFT HOLDING SLEEVE, SHAFT DIAMETER ENLARGING APPARATUS AND JIG
FOR SHAFT DIAMETER ENLARGING APPARATUS
Abstract
A shaft holding sleeve is inserted in a fitting hole of a
compressing machine of a shaft diameter enlarging apparatus that
applies an axial compression stress to a shaft stock to hold an end
portion of the shaft stock during a shaft diameter enlarging
process for radially enlarging a portion of the shaft stock. The
shaft holding sleeve includes a front end surface to be inserted in
the fitting hole, an exposed portion to be exposed to an outside of
the fitting hole, and at least one air communication passage
extending from the front end surface to a surface of the exposed
portion. A jig may be attached to the shaft diameter enlarging
apparatus to facilitate the insertion of the shaft holding sleeve
into the fitting hole.
Inventors: |
KUWAHARA; Yoshitaka; (Tokyo,
JP) ; MORI; Kazuki; (Tokyo, JP) ; OKAMOTO;
Mitsuhiro; (Tokyo, JP) ; IKEDA; Takashi;
(Tokyo, JP) ; IKUTA; Fumiaki; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NETUREN CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
52814167 |
Appl. No.: |
15/117293 |
Filed: |
March 17, 2015 |
PCT Filed: |
March 17, 2015 |
PCT NO: |
PCT/JP2015/058650 |
371 Date: |
August 8, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21J 5/08 20130101; B21J
13/00 20130101; B21K 1/12 20130101 |
International
Class: |
B21J 5/08 20060101
B21J005/08; B21J 13/00 20060101 B21J013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2014 |
JP |
2014-056519 |
Mar 19, 2014 |
JP |
2014-056520 |
Claims
1-17. (canceled)
18. A shaft holding sleeve to be inserted in a fitting hole of a
compressing machine that applies an axial compression stress to a
shaft stock to hold an end portion of the shaft stock during a
shaft diameter enlarging process for radially enlarging a portion
of the shaft stock, the shaft holding sleeve comprising: a front
end surface to be inserted in the fitting hole; an exposed portion
to be exposed to an outside of the fitting hole; and at least one
air communication passage extending from the front end surface to a
surface of the exposed portion.
19. The shaft holding sleeve according to claim 18, wherein the air
communication passage comprises a groove formed on an outer
peripheral surface of the shaft holding sleeve.
20. The shaft holding sleeve according to claim 18, wherein the air
communication passage comprises a through hole extending from the
front end surface to an opposite end surface of the shaft holding
sleeve.
21. The shaft holding sleeve according to claim 18, comprising an
attaching portion provided on an outer peripheral surface of the
shaft holding sleeve, the attaching portion being configured such
that a lifting lug is attachable and detachable with respect to the
attaching portion.
22. The shaft holding sleeve according to claim 18, comprising a
grip portion provided on the exposed portion.
23. The shaft holding sleeve according to claim 18, comprising a
surface-hardened portion at least at an opening portion of the
shaft holding sleeve from which the end portion of the shaft stock
is inserted into the shaft holding sleeve.
24. The shaft holding sleeve according to claim 23, wherein a
Vickers hardness of the surface-hardened portion is equal to or
greater than HV1200.
25. The shaft holding sleeve according to claim 18, comprising: a
cylindrical outer sleeve adapted to be fixed to the compressing
machine; and an inner sleeve provided inside the outer sleeve, the
inner sleeve being configured to accommodate the end portion of the
shaft stock and arranged to contact a radially enlarged portion of
the shaft stock, wherein the outer sleeve and the inner sleeve are
provide with an engaging structure configured to prevent a relative
movement of the inner sleeve with respect to the outer sleeve in a
direction opposite to a compression direction in which the shaft
stock is compressed.
26. The shaft holding sleeve according to claim 25, wherein the
engaging structure is provided on an inner peripheral surface of
the outer sleeve and on an outer peripheral surface of the inner
sleeve.
27. The shaft holding sleeve according to claim 26, wherein the
engaging structure comprises an annular concave-convex portion.
28. The shaft holding sleeve according to claim 27, wherein each
concave portion and convex portion of the engaging structure are
configured in a saw-tooth shape extending away from a center axis
of the outer sleeve and the inner sleeve in the direction opposite
to the compression direction.
29. The shaft holding sleeve according to claim 28, wherein the
inner peripheral surface of the outer sleeve and the outer
peripheral surface of the inner sleeve are formed in a tapered
shape extending away from the center axis of the outer sleeve and
the inner sleeve in the direction opposite to the compression
direction.
30. The shaft holding sleeve according to claim 27, wherein a depth
of each concave portion and a height of each convex portion of the
engaging structure are equal to or greater than 50 .mu.m and equal
to or smaller than 1% of an outer diameter of the inner sleeve.
31. The shaft holding sleeve according to claim 25, comprising a
surface-hardened portion at least at an opening portion of the
inner sleeve from which the end portion of the shaft stock is
inserted into the shaft holding sleeve.
32. The shaft holding sleeve according to claim 31, wherein a
Vickers hardness of the surface-hardened portion is equal to or
greater than HV1200.
33. A shaft diameter enlarging apparatus comprising: a pair of
shaft holding sleeves to hold respective end portions of a shaft
stock during a shaft diameter enlarging process for radially
enlarging a portion of the shaft stock; a compressing machine
having fitting holes into which the pair of shaft holding sleeves
are inserted respectively, the compressing machine being configured
to compress the shaft stock having the respective end portions held
by the pair of shaft holding sleeves in an axial direction of the
shaft stock; and a load generation device configured to apply, to
an intermediate portion of the shaft stock having the respective
end portions held by the pair of shaft holding sleeves, an
alternating load in a direction intersecting the axial direction,
wherein each of the shaft holding sleeves comprises: a front end
surface to be inserted in a corresponding one of the fitting holes;
an exposed portion to be exposed to an outside of the corresponding
one of the fitting holes; and at least one air communication
passage extending from the front end surface to a surface of the
exposed portion.
34. A jig for use with a shaft diameter enlarging apparatus
including a pair of shaft holding sleeves to hold respective end
portions of a shaft stock during a shaft diameter enlarging process
for radially enlarging a portion of the shaft stock, a compressing
machine having fitting holes into which the pair of shaft holding
sleeves are inserted respectively, the compressing machine being
configured to compress the shaft stock having the respective end
portions held by the pair of shaft holding sleeves in an axial
direction of the shaft stock, and a load generation device
configured to apply, to an intermediate portion of the shaft stock
having the respective end portions held by the pair of shaft
holding sleeves, an alternating load in a direction intersecting
the axial direction, wherein each of the shaft holding sleeves has
a front end surface to be inserted in a corresponding one of the
fitting holes an exposed portion to be exposed to an outside of the
corresponding one of the fitting holes, and at least one air
communication passage extending from the front end surface to a
surface of the exposed portion, the jig comprising a mounting
surface on which one of the shaft holding sleeves is mounted when
inserting the one of the shaft holding sleeves into the
corresponding one of the fitting holes, wherein, in a state in
which the jig is attached to an opening edge portion of the
corresponding one of the fitting holes, the mounting surface is
flush with an inner peripheral surface of the corresponding one of
the fitting holes.
Description
TECHNICAL FIELD
[0001] The present invention relates to a shaft holding sleeve, a
shaft diameter enlarging apparatus and a jig for the shaft diameter
enlarging apparatus.
BACKGROUND ART
[0002] A shaft diameter enlarging method is known as a method for
forming a large diameter portion on an axially intermediate portion
of a shaft stock. According to an example of the shaft diameter
enlarging method, a shaft stock is rotated with a bending angle
being given to the shaft stock in a state in which an axial
compression stress is applied to the shaft stock, thereby enlarging
a portion of the shaft stock to form the large diameter
portion.
[0003] A shaft diameter enlarging apparatus typically includes a
pair of shaft holding sleeves for holding respective end portions
of a shaft stock and a pair of spindles arranged along a reference
line, along which the shaft stock is arranged. Each spindle has a
fitting hole into which a corresponding holding sleeve is inserted.
The shaft holding sleeves are inserted into the fitting holes of
the respective spindles and fixed to the respective spindles. A
portion of the shaft stock is enlarged by moving one of the
spindles along the reference line to compress the shaft stock in
the axial direction thereof and by simultaneously rotating the
other spindle in a state in which the other spindle is tilted
relative to the reference line (see, e.g., JP 2013-166168 A).
[0004] The shaft holding sleeve is exchanged as needed in
accordance with, for example, dimensions of shaft stocks or wearing
of the shaft holding sleeve due to contact with the shaft stock.
However, when inserting or removing the shaft holding sleeve with
respect to the fitting hole, the air confined inside the fitting
hole may hinder a smooth insertion or removal of the shaft holding
sleeve.
[0005] The shaft holding sleeve may include an outer sleeve fixed
to the spindle and an inner sleeve press-fitted in the outer sleeve
so that only the inner sleeve need to be exchanged. The inner
sleeve is worn due to contact with the shaft stock. Thus, costs can
be reduced by exchanging only the inner sleeve.
[0006] However, the inner sleeve contacts a radially enlarged
portion of the shaft stock, and thus as the shaft stock is
compressed, a load is exerted on the inner sleeve in a direction
opposite to a compression direction in which the shaft stock is
compressed. If the load exerted on the inner sleeve is excessive,
the inner sleeve may be displaced relative to the outer sleeve in
the direction opposite to the compression direction.
SUMMARY OF INVENTION
[0007] The present invention has been made in view of above, and it
is an object thereof to improve a shaft diameter enlarging
work.
[0008] According to an aspect of the present invention, a shaft
holding sleeve is inserted in a fitting hole of a compressing
machine that applies an axial compression stress to a shaft stock
to hold an end portion of the shaft stock during a shaft diameter
enlarging process for radially enlarging a portion of the shaft
stock. The shaft holding sleeve includes a front end surface to be
inserted in the fitting hole, an exposed portion to be exposed to
an outside of the fitting hole, and at least one air communication
passage extending from the front end surface to a surface of the
exposed portion.
[0009] According to another aspect of the present invention, a
shaft diameter enlarging apparatus includes a pair of shaft holding
sleeves described above to hold respective end portions of a shaft
stock, a compressing machine having fitting holes into which the
pair of shaft holding sleeves are inserted respectively, the
compressing machine being configured to compress the shaft stock W
having the respective end portions held by the pair of shaft
holding sleeves in an axial direction of the shaft stock, and a
load generation device configured to apply, to an intermediate
portion of the shaft stock having the respective end portions held
by the pair of shaft holding sleeves, an alternating load in a
direction intersecting the axial direction.
[0010] According to another aspect of the present invention, a jig
for use with the shaft diameter enlarging apparatus described above
is provided. The jig includes a mounting surface on which the shaft
holding sleeve is mounted when inserting the shaft holding sleeve
into the fitting hole. In a state in which the jig is attached to
an opening edge portion of the fitting hole, the mounting surface
is flush with an inner peripheral surface of the fitting hole.
[0011] Other aspects and advantages of the invention will be
apparent from the following description, the drawings and the
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIGS. 1A to 1E are diagrams schematically illustrating an
example of a shaft diameter enlarging method;
[0013] FIGS. 2A to 2C are diagrams schematically illustrating
another example of the shaft diameter enlarging method;
[0014] FIGS. 3A and 3B are diagrams schematically illustrating yet
another example of the shaft diameter enlarging method;
[0015] FIGS. 4A and 4B are diagrams schematically illustrating yet
another example of the shaft diameter enlarging method;
[0016] FIGS. 5A and 5B are diagrams schematically illustrating yet
another example of the shaft diameter enlarging method;
[0017] FIG. 6 is a side view of an example of a shaft diameter
enlarging apparatus for performing the shaft diameter enlarging
method illustrated in FIGS. 1A to 1E;
[0018] FIG. 7 is a sectional view of a shaft holding sleeve and a
spindle of the shaft diameter enlarging apparatus of FIG. 6;
[0019] FIG. 8 is a front view of the shaft holding sleeve of FIG.
7;
[0020] FIG. 9 is a sectional view of another example of the shaft
holding sleeve;
[0021] FIG. 10 is a side view of yet another example of the shaft
holding sleeve;
[0022] FIG. 11 is a perspective view of yet another example of the
shaft holding sleeve;
[0023] FIG. 12 is a sectional view of another example of the shaft
holding sleeve and the spindle;
[0024] FIG. 13 is a diagram illustrating a configuration of the
shaft holding sleeve of FIG. 12;
[0025] FIG. 14 is a diagram illustrating a configuration of another
example of the shaft holding sleeve of FIG. 12;
[0026] FIG. 15 is a side view illustrating an example of a jig for
the shaft diameter enlarging apparatus;
[0027] FIG. 16 is a sectional view illustrating another example of
the jig for the shaft diameter enlarging apparatus; and
[0028] FIG. 17 is a front view of the jig for the shaft diameter
enlarging apparatus of FIG. 16.
DESCRIPTION OF EMBODIMENTS
[0029] FIGS. 1A to 5B are diagrams illustrating various examples of
a shaft diameter enlarging method.
[0030] In the shaft diameter enlarging method shown in FIGS. 1A to
1E, a shaft stock W is rotated while a bending angle is applied to
the shaft stock W in a state in which an axial compression stress
is exerted thereon, thereby enlarging a portion of the shaft stock
W.
[0031] As shown in FIG. 1A, both end portions of the shaft stock W
are respectively inserted into a pair of shaft holding sleeves 1a
and 1b arranged on a reference line A to face each other. In
addition, both end portions of the shaft stock W are respectively
abutted to bottoms of the shaft holding sleeves 1a and 1b, and thus
the shaft stock W is sandwiched by the pair of shaft holding
sleeves 1a and 1b. A predetermined gap D is interposed between the
pair of shaft holding sleeves 1a and 1b and the gap D is determined
depending on an axial length and an outer diameter of a radially
enlarged portion formed on the shaft stock W.
[0032] As shown in FIG. 1B, the shaft holding sleeve 1b is
translated along the reference line A so that the shaft stock W
sandwiched by the pair of shaft holding sleeves 1a and 1b is
axially compressed. Then, the shaft holding sleeve 1a is tilted
relative to the reference line A and also rotated, so that the
shaft stock W sandwiched by the pair of shaft holding sleeves 1a
and 1b is bent about a bending center O on the reference line A and
also is rotated about an axis of the shaft stock W. Due to bending
and rotating of the shaft stock W, an alternating load in a
direction interesting an axial direction of the shaft stock W is
exerted on the bent portion (an intermediate portion) of the shaft
stock W at an inner side and an outer side thereof in a bending
direction.
[0033] As shown in FIG. 1C, because the shaft stock W is compressed
in the axial direction thereof, the inner side of the bent portion
of the shaft stock W is swelled by plastic deformation, and
swelling by plastic deformation is grown over the entire
circumference thereof, so that the bent portion of the shaft stock
W is thickened.
[0034] As shown in FIG. 1D, when the gap between the pair of shaft
holding sleeves 1a and 1b reaches a target gap (the axial length of
the radially enlarged portion of the shaft stock W), compression of
the shaft stock W is stopped and the shaft holding sleeve 1a that
has been tilted relative to the reference line A is again arranged
along the reference line A, so that bending of the shaft stock W is
restored. According to the above procedures, enlarging processing
of the shaft stock W is finished and then rotating of the shaft
stock W is stopped.
[0035] Then, as shown in FIG. 1E, the shaft stock W is separated
from the pair of shaft holding sleeves 1a and 1b.
[0036] A shaft diameter enlarging method shown in FIGS. 2A to 2C is
identical to the shaft diameter enlarging method of FIGS. 1A to 1E,
in that as a shaft stock W is bent and is rotated about an axis
thereof, an alternating load is exerted on a bent portion (an
intermediate portion) of the shaft stock W. In this shaft diameter
enlarging method, instead of tilting one shaft holding sleeve 1a
relative to the reference line A, the shaft holding sleeve 1a is
slid in the direction intersecting the reference line A, thereby
bending the shaft stock W.
[0037] In a shaft diameter enlarging method shown in FIGS. 3A and
3B, an end portion of a shaft stock W is rotatably held in a
non-constraint state by one shaft holding sleeve 1a, an end portion
of the shaft stock W is non-rotatably held in a constraint state by
the other shaft holding sleeve 1b, and then the shaft holding
sleeve 1a and the end portion of the shaft stock W held by the
shaft holding sleeve 1a is pivoted about the reference line A,
thereby bending the shaft stock W and also exerting an alternating
load on a bent portion (an intermediate portion) of the shaft stock
W.
[0038] In a shaft diameter enlarging method shown in FIGS. 4A and
4B, end portions of a shaft stock W are non-rotatably held in a
constraint state by shaft holding sleeves 1a and 1b, respectively,
and one shaft holding sleeve 1a is reciprocatingly rotated about
the reference line A, thereby exerting an alternating load on an
intermediate portion of the shaft stock W.
[0039] In a shaft diameter enlarging method shown in FIGS. 5A and
5B, instead of displacement or rotation of shaft holding sleeves 1a
and 1b or shaft stock W, a bending or twisting oscillation is
applied from a oscillation generator OSC to the shaft stock W,
thereby exerting an alternating load on an intermediate portion of
the shaft stock W.
[0040] FIG. 6 shows a configuration of one example of a shaft
diameter enlarging apparatus for performing the shaft diameter
enlarging method shown in FIGS. 1A and 1E.
[0041] The shaft diameter enlarging apparatus 10 shown in FIG. 6
includes a pair of shaft holding sleeves 11 for holding end
portions of a shaft stock and a pair of holder units 12a, 12b
arranged to be spaced from each other along a reference line A,
along which the shaft stock is arranged. One holder unit 12a is
supported on a base 13 to be tiltable relative to the reference
line A. The other holder unit 12b is supported on the base 13 to be
movable along the reference line A.
[0042] Each of the holder units 12a, 12b includes a spindle 14, on
which the shaft holding sleeve is mounted, a housing 15 for
rotatably supporting the spindle 14, and a cylinder 16 for pushing
the end portion of the shaft stock, which has been inserted in the
shaft holding sleeve 11, out of the shaft holding sleeve 11. The
spindle 14 of each of the holder unit 12a, 12b is arranged on the
reference line A.
[0043] The shaft diameter enlarging apparatus 10 includes a
translational driving unit 17 for moving the holder unit 12b along
the reference line A, a tilting unit 18 for tilting the holder unit
12a relative to the reference line A and a rotation driving unit 19
for rotating the spindle 14 of the holder unit 12a. The holder
units 12a, 12b and the translational driving unit 17 form a
compressing machine for compressing the shaft stock in an axial
direction of the shaft stock. The holder units 12a, 12b, the
tilting unit 18 and the rotation driving unit 19 form a load
generation device for exerting, on an intermediate portion of the
shaft stock, an alternating load in a direction intersecting the
axial direction (the reference line A) of the shaft stock.
[0044] FIGS. 7 and 8 show configurations of the shaft holding
sleeve 11 and the spindle 14.
[0045] The spindle 14 is provided with a fitting hole 20, into
which the shaft holding sleeve 11 is inserted, and a pin insertion
hole 21 connected to the fitting hole 20. A pressure receiving
plate 22 for bearing the shaft holding sleeve 11 is fitted in the
fitting hole 20, and the pressure receiving plate 22 is butted and
fixed to a shoulder 23 formed inside the fitting hole 20. The pin
insertion hole 21 is provided to extend through the spindle 14
along a center axis (reference line A) of the spindle 14, and a
knock pin 24 of the cylinder 16 (see FIG. 6) is inserted through
the pin insertion hole 21.
[0046] The shaft holding sleeve 11 has a cylindrical portion 30 for
receiving the end portion of the shaft stock and a backing metal 31
fitted in the cylindrical portion 30. The cylindrical portion 30
has an accommodated portion 32 received in the fitting hole 20 of
the spindle 14 in a state in which the shaft holding sleeve 11 is
inserted in the fitting hole 20, and an exposed portion 33 exposed
out of the fitting hole 20. The exposed portion 33 is formed to
have a diameter smaller than that of the accommodated portion 32,
and a shoulder 34 is formed on a connection portion between the
exposed portion 33 and the accommodated portion 32. The backing
metal 31 forming a bottom of the shaft holding sleeve 11 is
supported by the knock pin 24 and bears an end surface of the shaft
stock W. Thus, the backing metal 31 is configured to be pressed by
the knock pin 24, so that the end portion of the shaft stock W
inserted in the shaft holding sleeve 11 is pushed out of the shaft
holding sleeve 11.
[0047] The shaft holding sleeve 11 inserted in the fitting hole 20
of the spindle 14 is fixed to the spindle 14 as the shoulder 34 of
the cylindrical portion 30 is pressed by a flange pipe 35 fastened
to an opening end of the spindle 14 in which the fitting hole 20 is
opened.
[0048] The shaft holding sleeve 11 is appropriately exchanged
depending on dimensions of shaft stocks. Also, the shaft holding
sleeve 11 receives a reaction force of an alternating load exerted
on the shaft stock, and in particular, a relatively large load is
applied to a surface 30a of an opening portion of the shaft holding
sleeve 11. Accordingly, the shaft holding sleeve 11 is worn due to
repeated uses and thus appropriately exchanged.
[0049] When along with exchange of the shaft holding sleeve 11, the
shaft holding sleeve 11 is inserted in and removed from the fitting
hole 20 of the spindle 14, air is confined inside the fitting hole
20 by the shaft holding sleeve 11, the spindle 14, the pressure
receiving plate 22 and the knock pin 24, and therefore the shaft
holding sleeve 11 is provided with an air communication passage for
communicating the inside of the fitting hole 20 with the
outside.
[0050] In the present example, the air communication passage of the
shaft holding sleeve 11 is composed of a groove 36 formed in an
outer peripheral surface of the accommodated portion 32. The groove
36 is provided to extend from a front end surface of the shaft
holding sleeve 11 on a side (a bottom side) of an insertion
direction into the fitting hole 20 along an axial direction of the
shaft holding sleeve 11 to reach a surface of the exposed portion
33. Although at least one groove 36 is sufficient as the air
communication passage, a plurality of grooves may be provided to be
spaced from each other in a circumferential direction of an outer
surface of the accommodated portion 32 as in the shown example.
[0051] If the groove 36 as the air communication passage is not
present, the inside of the fitting hole 20 is at a negative
pressure relative to an ambient pressure when the shaft holding
sleeve 11 is removed therefrom, whereas the inside of the fitting
hole 20 is at a positive pressure relative to the ambient pressure
when the shaft holding sleeve 11 is inserted therein, thereby
hindering the shaft holding sleeve 11 from being smoothly inserted
and removed. Contrarily, because the inside of the fitting hole 20
is communicated with the outside by the groove 36, the inside of
the fitting hole 20 is kept at the ambient pressure or a difference
in pressure from the ambient pressure is reduced. Accordingly, the
shaft holding sleeve 11 can be smoothly inserted and removed, so
that the replacement of the shaft holding sleeve 11 can be
facilitated, thereby contributing to an overall improvement in the
shaft diameter enlarging work.
[0052] Alternatively, the air communication passage of the shaft
holding sleeve 11 is not limited to the groove 36 in so far as the
air communication passage extends from the front end surface of the
shaft holding sleeve 11 inserted in the fitting hole 20 to a
surface of the exposed portion 33. For example, as shown in FIG. 9,
the air communication passage may be configured as a through hole
37 extending from the front end surface of the shaft holding sleeve
11 to the opposite end surface thereof.
[0053] As shown in FIG. 10, an attaching portion 39, to which a
lifting lug 38 is detachably fastened, may be provided on the outer
peripheral surface of the shaft holding sleeve 11. Because the
shaft holding sleeve 11 has a weight of about60 kg for a large
article and thus is relatively heavy although being varied
depending on the shaft stock to be held, the shaft holding sleeve
11 can be suspended via the lifting lug 38 so that the burden of
workers in an operation of exchanging the shaft holding sleeve 11
can be reduced. Thus, workability in exchanging of the shaft
holding sleeve 11 can be further improved.
[0054] In the example shown in FIGS. 6 and 7, the flange pipe 35
for fixing the shaft holding sleeve 11 to the spindle 14 is
constructed as a separate body from the cylindrical portion 30 of
the shaft holding sleeve 11. However, as shown in FIG. 11, the
cylindrical portion 30 may be integrally provided with a flange
portion 40. In this case, the flange portion 40 may be provided
with a handle 41 as a grip portion. When the handle 41 is provided,
operations of inserting and removing the shaft holding sleeve into
and from the fitting hole 20 of the spindle 14 can be easily
performed, and thus workability in exchanging of the shaft holding
sleeve can be further improved.
[0055] According to another example, the shaft holding sleeve 11
has a cylindrical outer sleeve 30A, an inner sleeve 30B inserted in
the outer sleeve 30A and a backing metal 31 fitted in the inner
sleeve 30B. The outer sleeve 30A is inserted in the fitting hole 20
of the spindle 14, and the outer sleeve 30A and the inner sleeve
30B inserted in the outer sleeve 30A are supported at rear end
surfaces thereof by the pressure receiving plate 22. Also, the
shoulder 34 provided on an outer peripheral surface of the outer
sleeve 30A is pressed by the flange pipe 35 fastened to the opening
end of the spindle 14 in which the fitting hole 20 is opened, and
as a result, the outer sleeve 30A is fixed to the spindle 14. The
inner sleeve 30B receives the end portion of the shaft stock W. The
backing metal 31 forming a bottom of the shaft holding sleeve 11 is
supported by the knock pin 24 and bears an end surface of the shaft
stock W. Thus, the backing metal 31 is configured to be pressed by
the knock pin 24, so that the end portion of the shaft stock W
inserted in the shaft holding sleeve 11 is pushed out of the shaft
holding sleeve 11.
[0056] The inner sleeve 30B receives a reaction force of an
alternating load exerted on the shaft stock, and in particular, a
relatively large load is applied to a surface 30a of an opening
portion of the inner sleeve 30B. Accordingly, the inner sleeve 30B
is worn due to repeated uses. The inner sleeve 30B inserted in the
outer sleeve 30A can be removed from the outer sleeve 30A, so that
only the inner sleeve 30B can be exchanged depending on a wear
degree.
[0057] The inner sleeve 30B contacts the radially enlarged portion
of the shaft stock during the shaft diameter enlarging process, and
thus as the shaft stock W is compressed, a load is exerted on the
inner sleeve 30B in a direction opposite to a compression direction
of the shaft stock W. For such a load, the outer sleeve 30A and the
inner sleeve 30B are provided with an engaging structure for
preventing a movement thereof in the direction opposite to the
compression direction of the shaft stock W.
[0058] FIG. 13 shows one example of the engaging structure provided
in the outer sleeve 30A and the inner sleeve 30B.
[0059] An annular concave-convex portion 70 is provided on an inner
peripheral surface of the outer sleeve 30A and an annular
concave-convex portion 71 to be engaged with the concave-convex
portion 70 of the outer sleeve 30A is provided on an outer
peripheral surface of the inner sleeve 30B. The concave-convex
portions 70, 71 of the outer sleeve 30A and the inner sleeve 30B
are engages with each other, thereby preventing the inner sleeve
30B from being displaced in the direction opposite to the
compression direction of the shaft stock due to the load.
[0060] A depth D of the concave portion and a height H of the
convex portion in each of the concave-convex portions 70, 71 is
preferably equal to or greater than 50 .mu.m and equal to or
smaller than 1% of an outer diameter of the inner sleeve 30B. Thus,
an engaging force larger than a friction caused by press-fitting
when the outer sleeve 30A and the inner sleeve 30B has a typical
surface roughness can be obtained, thereby reliably preventing the
inner sleeve 30B from being moved in the direction opposite to the
compression direction of the shaft stock.
[0061] In the above configuration, the inner sleeve 30B is inserted
into the outer sleeve 30A, for example, by shrinkage fitting. While
each of the concave-convex portions 70, 71 of the outer sleeve 30A
and the inner sleeve 30B has a plurality of concave portions and
convex portions, according to an alternative example, only one pair
of concave portion and convex portion may be provided.
[0062] FIG. 14 shows another example of the engaging structure
provided in the outer sleeve 30A and the inner sleeve 30B.
[0063] In the example shown in FIG. 14, each concave portion and
convex portion of the concave-convex portions 70, 71 of the outer
sleeve 30A and the inner sleeve 30B is configured in a saw-tooth
shape extending away from a center axis (the reference line A) of
the outer sleeve 30A and the inner sleeve 30B in the direction
opposite to the compression direction in which the shaft stock is
compressed. Also, the inner peripheral surface of the outer sleeve
30A and the outer peripheral surface of the inner sleeve 30B are
formed in a tapered shape extending away from the center axis (the
reference line A) of the outer sleeve 30A and the inner sleeve 30B
in the direction opposite to the compression direction.
[0064] According to the this example, the inner sleeve 30B can be
inserted into the outer sleeve 30A by press fitting, thereby
facilitating insertion of the inner sleeve 30B into the outer
sleeve 30A.
[0065] To suppress wearing of the shaft holding sleeve 11 due to
contact with the shaft stock, a hard material is preferably used as
a material for the shaft holding sleeve 11 (or the inner sleeve 30B
of the shaft holding sleeve 11). By suppressing wearing of the
shaft holding sleeve 11, a frequency of exchanging the shaft
holding sleeve 11 (or the inner sleeve 30B of the shaft holding
sleeve 11) can be lowered, thereby improving the shaft diameter
enlarging work.
[0066] As a base material forming the shaft holding sleeve 11 (or
the inner sleeve 30B of the shaft holding sleeve 11), a material
having a Rockwell hardness (JIS G 0202) of HRC58 or more can be
preferably used, and the material can include die steels, such as
SKD11, high speed steels, such as SKH51, semi-high speed steels or
like.
[0067] Also, from the viewpoint of suppressing wearing of the shaft
holding sleeve 11, a surface hardening treatment may be applied on
the shaft holding sleeve 11 (or the inner sleeve 30B of the shaft
holding sleeve 11). When the surface hardening treatment is
performed, the Vickers hardness (JIS Z 2244) of the hardened
surface is preferably equal to or greater than HV1200, more
preferably equal to or greater than HV3000. It is also preferable
that the hardened surface be smooth. Examples of surface hardening
treatment include coating, such as vanadium-based coating,
chromium-based coating, titanium-based coating or diamond-like
carbon (DLC) coating, nitriding and the like.
[0068] The surface hardening treatment is performed at least on a
surface 30a of the opening portion of the shaft holding sleeve 11,
and also may be performed on the entire inner peripheral surface of
the cylindrical portion 30 including the surface 30a of the opening
portion (or the entire inner peripheral surface of the inner sleeve
30B of the shaft holding sleeve 11) or may performed on the entire
surface of the shaft holding sleeve 11 (or the entire surface of
the inner sleeve 30B of the shaft holding sleeve 11).
[0069] When a coating is formed as the surface hardening treatment,
the coating may be composed of a single layer coating formed by
various coatings listed above or a multilayer coating formed by one
or more thereof. Examples of method of forming the coating can
include salt bath immersion method (thermo-reactive deposition and
diffusion method), chemical vapor deposition (CVD), physical vapor
deposition (PVD), plasma CVD (PCVD) and the like.
[0070] From the viewpoint of improving the shaft diameter enlarging
work, a jig may be used when exchanging the shaft holding sleeve
11.
[0071] FIG. 15 shows a configuration of one example of a jig for
the shaft diameter enlarging apparatus.
[0072] The jig 50 shown in FIG. 15 has a plurality of cylindrical
guide rods 51 (only one is shown in the figure). Screw holes are
provided in the opening end of the spindle 14 to which the flange
pipe 35 of the shaft holding sleeve 11 is fastened. The guide rod
51 shown in FIG. 15 is fastened to one of the screw holes located
vertically below the fitting hole 20 so that it is attached to an
opening edge portion of the fitting hole 20.
[0073] The shaft holding sleeve 11 is seated on the plurality of
guide rods 51 and thus mounted on the guide rods 51. An outer
peripheral surface of each guide rod 51 is flush with the inner
peripheral surface of the fitting hole 20 along a generatrix line
of the outer peripheral surface thereof that contacts the mounted
shaft holding sleeve 11, so that the shaft holding sleeve 11 is
smoothly moved from on the guide rods 51 into the fitting hole 20
and also from the fitting hole 20 onto the guide rods 51.
Therefore, operations of inserting and removing the shaft holding
sleeve 11 can be easily performed, and thus workability in
exchanging of the shaft holding sleeve 11 can be further
improved.
[0074] Also, in the shown example, each of the guide rods 51 is
provide at a distal end thereof with a large diameter stopper
portion 52, and the stopper portion 52 is abutted to the shaft
holding sleeve 11 to prevent the shaft holding sleeve 11 from being
dropped out, in a case where the shaft holding sleeve 11 is
excessively moved toward the distal ends of the guide rods 51, such
as when the shaft holding sleeve 11 is removed from the fitting
hole 20.
[0075] After the shaft holding sleeve 11 is inserted into the
fitting hole 20, the guide rods 51 are separated from the spindle
14, and then instead of the guide rods 51, the flange pipe 35 is
fastened to the spindle 14 so that the shaft holding sleeve 11 is
fixed to the spindle 14.
[0076] FIGS. 16 and 17 show a configuration of another example of
the jig for the shaft diameter enlarging apparatus.
[0077] The jig 60 shown in FIGS. 16 and 17 is formed in an annular
shape and is fitted on the outer side of the opening end of the
spindle 14 to be mounted to the spindle 14. The jig 60 has a
half-cylindrical support portion 62 formed to protrude from a lower
edge, in the vertical direction, of an opening 61 exposing the
fitting hole 20, and the shaft holding sleeve 11 is mounted to the
support portion 62. An inner peripheral surface of the support
portion 62 is flush with the inner peripheral surface of the
fitting hole 20, so that the shaft holding sleeve 11 is smoothly
moved from on the support portion 62 into the fitting hole 20 and
also from the fitting hole 20 onto the support portion 62.
According to the jig 60 of the present example, the jig 60 can be
easily mounted to and removed from the spindle 14 and workability
in exchanging of the shaft holding sleeve 11 can be further
improved.
[0078] In the foregoing, although the shaft holding sleeve, the
shaft diameter enlarging apparatus and the jig for the shaft
diameter enlarging apparatus of the present invention has been
described, as an example, with respect to the shaft diameter
enlarging apparatus 10 for performing the shaft diameter enlarging
method shown in FIGS. 1A to 1E, shaft diameter enlarging
apparatuses for performing the shaft diameter enlarging methods
respectively shown in FIGS. 2A to 5B are only different in a holder
unit or an operating manner of the spindle for exerting an
alternating load on the intermediate portion of the shaft stock,
and thus the configurations of the shaft holding sleeve and the jig
for the shaft diameter enlarging apparatus as described above can
be also applied to such shaft diameter enlarging apparatuses.
[0079] Next, Examples of the shaft holding sleeve 11 (or the inner
sleeve 30B of the shaft holding sleeve 11) and life evaluations
thereof will be described.
[0080] Regarding Example 1, semi-high speed steel was used as the
base material, and surface hardening treatment was omitted. As for
Example 2, semi-high speed steel was used as the base material and
nitriding was performed as surface hardening treatment. As for
Example3, SKH51 (high speed steel) was used as the base material,
and as surface hardening treatment, a VC (vanadium carbide) coating
was formed by TD Process (trademark), a type of salt bath immersion
method. Base material hardnesses and surface properties of the
sleeves of Examples 1 to 3 are shown in Table 1.
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Base material
Semi-high Semi-high SKH51 speed steel speed steel Base material
hardness HRC 60-64 HRC 60-64 HRC 60-64 Surface hardening No
Nitriding VC coating formin by TD Process Surface hardness HV1250
HV3000 or more Galling life 0 11 396
[0081] With respect to each of the sleeves of Examples 1 to 3,
shaft diameter enlarging process was repeatedly performed under the
same conditions by the shaft diameter enlarging apparatus 10
described above, and then the number of shaft stocks processed
until a visible galling (adhesion wear) occurred was evaluated as a
life. The evaluation results are shown in Table 1. From the
evaluation results shown in Table 1, it can be found that wearing
of the sleeves due to contact with shaft stocks can be suppressed
by performing the surface hardening treatment. In addition, by
suppressing wearing of the shaft holding sleeve 11, a frequency of
exchanging the sleeves can be lowered, thereby improving the shaft
diameter enlarging work.
[0082] According to one or more embodiments of the present
invention, a shaft holding sleeve 11 is inserted in a fitting hole
20 of a compressing machine 12a, 12b, 17 that applies an axial
compression stress to a shaft stock W to hold an end portion of the
shaft stock W during a shaft diameter enlarging process for
radially enlarging a portion of the shaft stock W. The shaft
holding sleeve 11 includes a front end surface to be inserted in
the fitting hole 20, an exposed portion 33 to be exposed to an
outside of the fitting hole 20, and at least one air communication
passage 36, 37 extending from the front end surface to a surface of
the exposed portion 33.
[0083] The air communication passage 36, 37 may include a groove 36
formed on an outer peripheral surface of the shaft holding sleeve
11.
[0084] The air communication passage 36, 37 may include a through
hole 37 extending from the front end surface to an opposite end
surface of the shaft holding sleeve 11.
[0085] The shaft holding sleeve 11 may further include an attaching
portion 39 provided on an outer peripheral surface of the shaft
holding sleeve 11, the attaching portion 39 being configured such
that a lifting lug 38 is attachable and detachable with respect to
the attaching portion 39.
[0086] The shaft holding sleeve 11 may further include a grip
portion 41 provided on the exposed portion 33.
[0087] The shaft holding sleeve 11 may further include a
surface-hardened portion 30a at least at an opening portion of the
shaft holding sleeve 11 from which the end portion of the shaft
stock W is inserted into the shaft holding sleeve 11.
[0088] A Vickers hardness of the surface-hardened portion 30a may
be equal to or greater than HV1200.
[0089] According to one or more embodiments of the present
invention, a shaft diameter enlarging apparatus 10 includes a pair
of shaft holding sleeves 11 described above to hold respective end
portions of a shaft stock, a compressing machine 12a, 12b, 17
having fitting holes 20 into which the pair of shaft holding
sleeves 11 are inserted respectively, the compressing machine 12a,
12b, 17 being configured to compress the shaft stock W having the
respective end portions held by the pair of shaft holding sleeves
11 in an axial direction of the shaft stock W, and a load
generation device 18, 19 configured to apply, to an intermediate
portion of the shaft stock W having the respective end portions
held by the pair of shaft holding sleeves 11, an alternating load
in a direction intersecting the axial direction.
[0090] According to one or more embodiments of the present
invention, a jig 50, 60 for use with the shaft diameter enlarging
apparatus 10 described above is provided. The jig 50, 60 includes a
mounting surface on which the shaft holding sleeve 11 is mounted
when inserting the shaft holding sleeve 11 into the fitting hole
20. In a state in which the jig 50, 60 is attached to an opening
edge portion of the fitting hole 20, the mounting surface is flush
with an inner peripheral surface of the fitting hole 20.
[0091] According to one or more embodiments of the present
invention, a shaft holding sleeve 11 is configured to hold an end
portion W of a shaft stock during a shaft diameter enlarging
process for radially enlarging a portion of the shaft stock W. The
shaft holding sleeve 11 includes a cylindrical outer sleeve 30A
adapted to be fixed to a compressing machine 12a, 12b, 17 that
applies an axial compression stress to the shaft stock W, and an
inner sleeve 30B provided inside the outer sleeve. The inner sleeve
30B is configured to accommodate the end portion of the shaft stock
W and is arranged to contact the radially enlarged portion of the
shaft stock W. The outer sleeve and the inner sleeve are provide
with an engaging structure 70, 71 configured to prevent a relative
movement of the inner sleeve 30B with respect to the outer sleeve
30A in a direction opposite to a compression direction in which the
shaft stock W is compressed.
[0092] The engaging structure 70, 71 may be provided on an inner
peripheral surface of the outer sleeve 30A and on an outer
peripheral surface of the inner sleeve 30B.
[0093] The engaging structure 70, 71 may include an annular
concave-convex portion.
[0094] Each concave portion and convex portion of the engaging
structure 70, 71 may be configured in a saw-tooth shape extending
away from a center axis A of the outer sleeve 30A and the inner
sleeve 30B in the direction opposite to the compression
direction.
[0095] The inner peripheral surface of the outer sleeve and the
outer peripheral surface of the inner sleeve may be formed in a
tapered shape extending away from the center axis A of the outer
sleeve 30A and the inner sleeve 30B in the direction opposite to
the compression direction.
[0096] A depth of each concave portion and a height of each convex
portion of the engaging structure 70, 71 may be equal to or greater
than 50 .mu.m and equal to or smaller than 1% of an outer diameter
of the inner sleeve 30B.
[0097] The shaft holding sleeve 11 may further include a
surface-hardened portion 30a at least at an opening portion of the
inner sleeve 30B from which the end portion of the shaft stock W is
inserted into the shaft holding sleeve 11.
[0098] A Vickers hardness of the surface-hardened portion 30a may
be equal to or greater than HV1200.
[0099] This application is based on Japanese Patent Application
Nos. 2014-056519 and 2014-056520,both filed on Mar. 19, 2014, the
entire contents of which are incorporated herein by reference.
* * * * *