U.S. patent application number 14/773307 was filed with the patent office on 2016-01-21 for linear grinding member, brush-like grinding stone, and method for manufacturing linear grinding member.
The applicant listed for this patent is TAIMEI CHEMICALS CO., LTD., XEBEC TECHNOLOGY CO., LTD.. Invention is credited to Mitsuhisa AKASHI, Suguru MATSUSHITA.
Application Number | 20160016293 14/773307 |
Document ID | / |
Family ID | 51491461 |
Filed Date | 2016-01-21 |
United States Patent
Application |
20160016293 |
Kind Code |
A1 |
MATSUSHITA; Suguru ; et
al. |
January 21, 2016 |
LINEAR GRINDING MEMBER, BRUSH-LIKE GRINDING STONE, AND METHOD FOR
MANUFACTURING LINEAR GRINDING MEMBER
Abstract
A brush-like grinding stone (1) includes a linear grinding
member (11) obtained by stiffening, with a resin binder, a
composite yarn including inorganic filaments. As the linear
grinding member (11), a linear grinding member (11A) having a
square cross-sectional shape, a linear grinding member (11B) having
a rectangular cross-sectional shape, or a linear grinding member
(11C) having an elliptical cross-sectional shape is used. While the
linear grinding member (11A) is hard to bend in the diagonal
directions of the cross section, the linear grinding member (11B)
and the linear grinding member (11C) are hard to bend in directions
along the long side and the major axis, respectively, of the cross
section. Thus, each of the linear grinding members (11A to 11C) has
an edge effect and provides high grading performance.
Inventors: |
MATSUSHITA; Suguru; (Nagano,
JP) ; AKASHI; Mitsuhisa; (Nagano, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAIMEI CHEMICALS CO., LTD.
XEBEC TECHNOLOGY CO., LTD. |
Kamiina-gun, Nagano
Chiyoda-ku, Tokyo |
|
JP
JP |
|
|
Family ID: |
51491461 |
Appl. No.: |
14/773307 |
Filed: |
March 7, 2014 |
PCT Filed: |
March 7, 2014 |
PCT NO: |
PCT/JP2014/056028 |
371 Date: |
September 4, 2015 |
Current U.S.
Class: |
451/532 ;
51/298 |
Current CPC
Class: |
B24D 13/10 20130101;
A46B 2200/30 20130101; A46B 2200/3093 20130101; B24D 3/344
20130101; B24D 18/0027 20130101; B24D 13/145 20130101; B24D 3/28
20130101; A46D 1/00 20130101 |
International
Class: |
B24D 13/10 20060101
B24D013/10; B24D 13/14 20060101 B24D013/14; B24D 18/00 20060101
B24D018/00; A46D 1/00 20060101 A46D001/00; B24D 3/28 20060101
B24D003/28 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 8, 2013 |
JP |
2013-046982 |
Claims
1. A linear grinding member comprising a composite yarn including
inorganic filaments that has been stiffened with a resin binder,
wherein the linear grinding member has a square, rectangular, or
elliptical cross-sectional shape.
2. The linear grinding member according to claim 1, wherein the
linear grinding member has a rectangular or elliptical
cross-sectional shape an aspect ratio of which is in a range of 1.1
to 5.0.
3. The linear grinding member according to claim 1, wherein the
composite yarn has been twisted.
4. The linear grinding member according to claim 3, wherein the
linear grinding member has a square cross-sectional shape, and a
length dimension of the linear grinding member corresponding to one
turn of twisting is set in a range of 1 cm to 4 cm.
5. The linear grinding member according to claim 3, wherein the
linear grinding member has a rectangular or elliptical
cross-sectional shape, and a length dimension of the linear
grinding member corresponding to one turn of twisting is set in a
range of 1 cm to 4 cm if the aspect ratio is in a range of 1.1 to
1.9, and is set in a range of 10 cm to 20 cm if the aspect ratio is
in a range of 2.0 to 5.0.
6. A brush-like grinding stone comprising: a plurality of linear
grinding members; and a holder that holds the plurality of linear
grinding members in the form of bundles, wherein each of the linear
grinding members is obtained by stiffening, with a resin binder, a
composite yarn including inorganic filaments, and each of the
linear grinding members has a square, rectangular, or elliptical
cross-sectional shape.
7. A method for manufacturing a linear grinding member obtained by
stiffening, with a resin binder, a composite yarn including
inorganic filaments, the method comprising: an impregnation step of
impregnating the composite yarn with an uncured resin binder; a
shaping step of passing the composite yarn impregnated with the
resin binder through a die to shape a cross-sectional shape of the
composite yarn into a square, rectangle, or ellipse; and a
resin-curing step of curing the resin binder after the shaping step
or in parallel with the shaping step.
8. The method for manufacturing a linear grinding member according
to claim 7, further comprising a twisting step of twisting the
composite yarn before the impregnation step.
9. A method for manufacturing a linear grinding member obtained by
stiffening, with a resin binder, a composite yarn including
inorganic filaments, the method comprising: an impregnation step of
impregnating the composite yarn with an uncured resin binder; a
resin-curing step of curing the resin binder; and a polishing
shaping step of polishing an outer circumferential surface of the
composite yarn to shape a cross-sectional shape of the composite
yarn into a square, rectangle, or ellipse.
Description
FIELD
[0001] The present invention relates to: a linear grinding member
including inorganic filaments stiffened with a resin binder, a
brush-like grinding stone having linear grinding members held by a
holder, and a method for manufacturing a linear grinding
member.
BACKGROUND
[0002] Patent Literatures 1 and 2 disclose brush-like grinding
stones each including a plurality of linear grinding members, and a
holder that holds these linear grinding members in a bundle. When
each of these brush-like grinding stones is used, for example, for
deburring or polishing a surface of a metal workpiece, the tips of
the linear grinding members grind or polish the surface while the
brush-like grinding stone is rotated about the axis thereof, Patent
Literature 1 discloses, as a method for manufacturing a linear
grinding member, a method including: impregnating a composite yarn
including inorganic filaments and a resin binder; then winding it
up while removing excess resin with a squeezing roller; and then
thermally curing the resin binder.
CITATION LIST
Patent Literatures
[0003] Patent Literature 1: Japanese Patent Laid-open Publication
No. 2002-210662
[0004] Patent Literature 2: WO2004/009293
SUMMARY
Technical Problem
[0005] In the manufacturing method disclosed in Patent Literature
1, when a composite yarn including inorganic filaments is driven
while being placed on a roller or the like, the composite yarn is
moderately pressed against the roller. As a result, the cross
section of the composite yarn is formed into a circular shape.
Thus, a linear grinding member having a circular cross section is
manufactured.
[0006] In this respect, bending of a linear grinding member having
a circular cross section is uniformly likely in all directions. The
linear grinding member makes regular motions, therefore providing
no edge effect, during processing. As a result, the linear grinding
member cannot fully exert its grinding performance in some
cases.
[0007] In consideration of the above problem, the present invention
aims at providing a linear grinding member and a brush-like
grinding stone that have edge effects and provides high grinding
performance. The present invention also aims at providing a method
for manufacturing such a linear grinding member.
Solution to Problem
[0008] The present invention has been made based on new knowledge
found by the inventors that, when a linear grinding member is used
in a brush-like grinding stone, the cross-sectional shape of the
linear grinding member affects the polishing performance and the
grinding performance thereof.
[0009] In order to solve the above problem, the present invention
provides a linear grinding member obtained by stiffening, with a
resin binder, a composite yarn including inorganic filaments, where
the linear grinding member has a square, rectangular, or elliptical
cross-sectional shape.
[0010] A linear grinding member having a square cross-sectional
shape according to the present invention is hard to bend and firm
because the cross section thereof has the same dimension in the
lateral and longitudinal directions. A linear grinding member
having a square cross-sectional shape has an edge effect because it
is harder to bend in the diagonal directions of the cross section
than in the lateral and longitudinal directions thereof. Thus, a
linear grinding member having a square cross-sectional shape has
excellent grindability. In the present invention, a linear grinding
member having a rectangular cross-sectional shape has a cross
section thinner in the thickness direction than in the width
direction (a direction along the long sides). Therefore, the tip
thereof easily breaks, and the self-sharpening action for
generating a new cutting edge is active. Thus, such a linear
grinding member can maintain grinding performance. A linear
grinding member having a rectangular cross-sectional shape also has
an edge effect because it is hard to bend in a direction along the
long sides and the diagonal directions of the cross section.
Furthermore, a linear grinding member having a rectangular
cross-sectional shape has different degrees of easiness to bend in
the thickness direction and width direction of the cross-section,
and consequently makes irregular motions during processing. Thus, a
linear grinding member having a rectangular cross-sectional shape
provides increased grinding performance because it makes irregular
motions and has an edge effect at the same time. Also in the
present invention, a linear grinding member having an elliptical
cross-sectional shape has a cross section thinner in the thickness
direction than in the width direction (a direction along the major
axis). Therefore, the front end thereof easily breaks, and the
self-sharpening action for generating a new cutting edge actively
works. Thus, such a linear grinding member can maintain grinding
performance. A linear grinding member having an elliptical
cross-sectional shape also has an edge effect because it is hard to
bend in a direction along the major axis of the cross section.
Furthermore, a linear grinding member having an elliptical
cross-sectional shape has different degrees of easiness to bend in
the thickness direction and width direction of the cross-section,
and consequently makes irregular motions during processing. Thus, a
linear grinding member having an elliptical cross-sectional shape
provides increased grinding performance because it makes irregular
motions and has an edge effect at the same time. Note that, during
processing of a workpiece, the tip of a linear grinding member
provides a process similar to grinding. For this reason,
"polishing" and "grinding" are used without distinction
therebetween in the present specification.
[0011] The present invention may employ a linear grinding member
having a rectangular or elliptical cross-sectional shape and having
an aspect ratio in the range of 1.1 to 5.0. It has been found that,
when having an aspect ratio in the range of 1.1 to 5.0, a linear
grinding member is less likely to bend in a direction along the
long sides or the major axis of the cross section and exerts an
edge effect. An aspect ratio is a value obtained by dividing a
dimension of the long side or the major axis by a dimension of the
short side or the minor axis. Here, an adjustment such as
increasing the aspect ratio for higher grinding performance or
decreasing the aspect ratio for lower grinding performance can be
made. Note that the surface roughness of a workpiece after
processing tends to be rougher when processing efficiency is
increased with the aspect ratio increased, and tends to be finer
when processing efficiency is decreased with the aspect ratio
decreased.
[0012] In the present invention, the composite yarn may have been
twisted. With the composite yarn appropriately twisted,
longitudinal cracks (cracks in the lengthwise direction of the
linear grinding member) in the linear grinding member can be
prevented, and impactive wear can be prevented.
[0013] In this case, the present invention may employ a linear
grinding member having a square cross-sectional shape and having a
length dimension of the linear grinding member corresponding to one
turn of twisting set in the range of 1 cm to 4 cm. With the length
dimension of the linear grinding member corresponding to one turn
of twisting set to 4 cm or less, the effect of preventing a
longitudinal crack in the linear grinding member can be obtained.
With the length dimension of the linear grinding member
corresponding to one turn of twisting set to 1 cm or more, the
inorganic filaments can be prevented from fuzzing because of the
twisting.
[0014] In this case, for a linear grinding member that has a
rectangular or elliptical cross-sectional shape, a length dimension
of the linear grinding member corresponding to one turn of twisting
may be set in the range of 1 cm to 4 cm when the aspect ratio is in
the range of 1.1 to 1.9, and may be set in the range of 10 cm to 20
cm when the aspect ratio is in the range of 2.0 to 5.0. When the
aspect ratio is set in the range of 1.1 to 1.9, the effect of
preventing longitudinal cracks of the linear grinding member can be
obtained with the length dimension of the linear grinding member
corresponding to one turn of twisting set to 4 cm or less. With the
length dimension of the linear grinding member corresponding to one
turn of twisting set to 1 cm or more, the inorganic filaments can
be prevented from fuzzing because of the twisting. When the aspect
ratio is in the range of 2.0 to 5.0, the effect of preventing
longitudinal cracks of the linear grinding member can be obtained
with the length dimension of the linear grinding member
corresponding to one turn of twisting set to 20 cm or less, even
for the linear grinding member that has a large aspect ratio of 2.0
or higher. With the length dimension of the linear grinding member
corresponding to one turn of twisting set to 10 cm or more, the
inorganic filaments can be prevented from fuzzing because of the
twisting, even for the linear grinding member that has a large
aspect ratio of 2.0 or higher.
[0015] Next, a brush-like grinding stone according to the present
invention includes: a plurality of linear grinding members; a
holder that holds the plurality of linear grinding members in the
form of a bundle. In the brush-like grinding stone, each of the
linear grinding members is obtained by stiffening a composite yarn
including inorganic filaments, and each of the linear grinding
members has a square, rectangular, or elliptical cross-sectional
shape.
[0016] According to the present invention, each of the multiple
linear grinding members has an edge effect, and provides high
grinding performance, which makes it easier to process a workpiece
with the brush-like grinding stone.
[0017] Furthermore, the present invention provides a method of
manufacturing a linear grinding member obtained by stiffening, with
a resin binder, a composite yarn including inorganic filaments. The
method includes: an impregnation step of impregnating the composite
yarn with an uncured resin binder; a shaping step of passing the
composite yarn impregnated with the resin binder through a die to
shape the cross-sectional shape of the composite yarn into a
square, rectangle, or ellipse; and a resin-curing step of curing
the resin binder after the shaping step or in parallel with the
shaping step.
[0018] According to the present invention, when a linear grinding
member is manufactured, the shaping step of passing the composite
yarn impregnated with the resin binder through a die to shape the
cross-sectional shape of the composite yarn is performed after the
composite yarn is impregnated with the uncured resin binder in the
impregnation step, and before or in parallel with the resin binder
is cured in the resin-curing step. Thus, the cross-sectional shape
of the linear grinding member can be easily controlled.
[0019] In the present invention, a twisting step of twisting the
composite yarn may be performed before the impregnation step. This
step causes the inorganic filaments in the composite yarn to tangle
together as a result of the twisting of the composite yarn, thereby
making it easier to control the cross-sectional shape of the linear
grinding member than in a case where the inorganic filaments extend
parallel to one another. Appropriately twisting the composite yarn
can prevent longitudinal cracks in the linear grinding member
(cracks in the lengthwise direction of the linear grinding member),
and can prevent impactive wear.
[0020] Another aspect of the present invention provides a method of
manufacturing a linear grinding member obtained by stiffening, with
a resin binder, a composite yarn including inorganic filaments. The
method includes: an impregnation step of impregnating the composite
yarn with an uncured resin binder; a resin-curing step of curing
the resin binder; and a polishing shaping step of polishing the
outer peripheral surface of the composite yarn to shape the
cross-sectional shape of the composite yarn into a square,
rectangle, or ellipse.
[0021] According to the present invention, thus polishing the outer
peripheral surface of the composite yarn makes it easier to shape
the cross-sectional shape of the linear grinding member.
BRIEF DESCRIPTION OF DRAWING
[0022] FIG. 1 is an illustration of a brush-like grinding stone
according to a first example of the present invention.
[0023] FIG. 2 is an illustration of a brush-like grinding stone
according to a second example of the present invention.
[0024] FIG. 3 is an illustration of a brush-like grinding stone
according to a third example of the present invention.
[0025] FIG. 4 is an illustration schematically depicting a linear
grinding member of the first example according to the present
invention.
[0026] FIG. 5 is an illustration of twisting of a composite yarn
for a linear grinding member.
[0027] FIG. 6 is an illustration schematically depicting a linear
grinding member of the second example according to the present
invention.
[0028] FIG. 7 is an illustration schematically depicting a linear
grinding member of the third example according to the present
invention.
[0029] FIG. 8 is an illustration depicting a method for
manufacturing a linear grinding member of the first example
according to the present invention.
[0030] FIG. 9 is an illustration depicting a method for
manufacturing a linear grinding member of the second example of the
present invention.
DESCRIPTION OF EMBODIMENTS
[0031] A brush-like grinding stone and a polishing machine brush
according to embodiments of the present invention are described
below with reference to the drawings.
First Example of Brush-like Grinding Stone
(Entire Structure of Polishing Machine Brush)
[0032] FIG. 1 is an illustration of a brush-like grinding stone
according to a first example of the present invention. A polishing
machine brush 10 illustrated in FIG. 1 is a tool for, for example,
deburring and polishing a surface of a metal workpiece, and
includes: a brush-like grinding stone 1; a brush case 2 that holds
this brush-like grinding stone 1; and a fixing screw 3 for fixing
the brush-like grinding stone 1 to the brush case 2.
[0033] The brush-like grinding stone 1 includes: a plurality of
linear grinding members 11; and a holder 12 that holds respective
base-end parts of the linear grinding members 11. In this
embodiment, the plurality of linear grinding members 11 are held by
the holder 12 in the form of a plurality of bundles 110 each
includes the multiple linear grinding members 11. The bundles 110
are arranged at uniform angle intervals around the rotational
center axis line L of the polishing machine brush 10.
[0034] The linear grinding member 11 is obtained by impregnating a
collection of inorganic filaments with binder resin and then
forming the conglomerate into a linear shape. Examples of the
inorganic filaments include alumina fiber filaments. Examples of
the binder resin include: thermosetting resin such as epoxy resin
and phenolic resin; silicone resin; and thermoplastic resin such as
polyester resin, polypropylene resin, and polyamide resin. A
composite yarn is obtained by gathering, for example, 250 to 3000
alumina fiber filaments (inorganic filaments) each having a
filament diameter of 8 to 50 .mu.m. The diameter of the composite
yarn is 0.1 mm to 2 mm. Correspondingly, the linear grinding member
11 has a diameter equal to that of the composite yarn, which is 0.1
mm to 2 mm. A material for the inorganic filaments is not
particularly limited as long as the material has a polishing
property effective, in a relative sense, for a material to be
polished, i.e., as long as the material is harder and more brittle
than a material to be polished. Other than alumina fiber, usable
examples include silicon carbide fiber, boron fiber, and glass
fiber. Any ones of the above materials may be used in combination
depending on a material to be polished. Alumina fiber and silicon
carbide fiber have polishing properties that are very effective for
ferrous metals and non-ferrous metals, respectively.
[0035] The holder 12 is made of metal or resin, and has a columnar
outer shape. Alternatively, the holder 12 may have an outer shape
like a quadrangle prism. At one end side of the holder 12, a
cylindrical grinding material holding portion 12a that opens in the
axis line direction is formed. The base end sections of the bundles
100 of the linear grinding members 11 are inserted into the
grinding material holding portion 12a, and are glued and fixed
thereto, whereby the linear grinding member 11 and the holder 12
are integrally joined together.
[0036] The brush case 2 includes a cylindrical circumferential wall
part 21 having a bottom, and a driving connecting shaft 22 extended
from one end side of the circumferential wall part 21 in a
direction along a central axis line (a rotational center axis line
L) of the circumferential wall part 21. The inner diameter
dimension of the circumferential wall part 21 is slightly larger
than the outer diameter dimension of the holder 12. In this
embodiment, the brush case 2 is made of metal or resin. The driving
connecting shaft 22 is used for attaching the polishing machine
brush 10 to a polishing apparatus, and rotation driving force is
transmitted to the polishing machine brush 10 via the driving
connecting shaft 22, thereby bringing polishing actions into
operation. Normally, the polishing machine brush 10 is driven so as
to rotate about the rotational center axis line L. However, the
movement thereof is not limited to rotation, and may be a
reciprocating movement, an oscillation movement, swinging, or a
combination of any ones of these movements may be made.
(Structure for Fixing Brush-Like Grinding Stone to Brush Case)
[0037] In this embodiment, for fixing the brush-like grinding stone
1 to the brush case 2 by the fixing screw 3, one opening section
21a is formed in the circumferential wall part 21 of the brush case
2. The opening section 21a is formed like a slotted hole and
extends in the axial direction. Additionally, the inner
circumferential surface of the circumferential wall part 21 has a
flat surface (not illustrated) formed on a region thereof opposite
to the opening section 21a across the rotational center axis line
L. The flat surface extends in the axial direction. The
circumferential wall part 21 also has a thin-walled section 21c
having a smaller thickness than the other portion thereof. This
thin-walled section 21c has a shape obtained by thinly and flatly
scraping a part of the outer circumferential surface of the
circumferential wall part 21 for a predetermined length in the
axial direction. In this embodiment, two thin-walled sections 21c
are formed on opposite sides of a position that is opposite from
the opening section 21a across the rotational center axis line L.
Consequently, the center of gravity of the brush case 2 is located
on the rotational center axis line L because the circumferential
wall part 21 has the two thin-walled sections 21c and the flat
surface formed thereon while having the opening section 21a formed
therein.
[0038] In the upper end part of the holder 12, a screw hole 12b is
drilled therethrough passing the rotational center axis line L and
perpendicularly to the rotational center axis line L. The screw
hole 12b is a part to which fixing screw 3 is fixed by being
screwed thereinto when the brush-like grinding stone 1 is assembled
to the brush case 2. In this embodiment, a hexagon socket set screw
is used as the fixing screw 3, and the fixing screw 3 has a hexagon
socket 31 formed on an end thereof. The hexagon socket 31 is a part
into which the head of a hexagon wrench 5 is fitted.
[0039] The brush-like grinding stone 1 and the polishing machine
brush 10, which are thus structured, are rotated about the
rotational center axis line L with the tips of the linear grinding
members 11 pressed against a workpiece, thereby removing burrs
generated during molding or processing, or polishing the surface of
the workpiece. The workpiece is, for example, a magnesium or
aluminum die-cast product. Otherwise, the workpiece may be a steel
member processed with such a tool as an end mill, a drill, a die,
or a tap.
(Method for Assembling Polishing Machine Brush, and Method for
Adjusting Projection Dimension of Linear Grinding Member)
[0040] In assembling the polishing machine brush 10 to which the
present invention is applied, when the brush-like grinding stone 1
is assembled to the brush case 2 and fixed by the fixing screw 3,
the brush-like grinding stone 1 is inserted into the brush case 2
from the side of the holder 12. Thereafter, the brush-like grinding
stone 1 is slid in the axial direction inside the brush case 2, so
that a position of the assembly is adjusted to make the free end
parts of the linear grinding members 11 project by a desired length
from an opening on one end side of the circumferential wall part
21. When the brush-like grinding stone 1 is thus slid, the position
thereof is circumferentially adjusted during the sliding so that
the opening of the screw hole 12b of the holder 12 can be seen
through the opening section 21a formed in the brush case 2. Thus,
access to the screw hole 12b provided in the holder 12 is allowed
through the opening section 21a.
[0041] Subsequently, the fixing screw 3 is screwed into the screw
hole 12b through the opening section 21a, and tightened up in a
direction from the opening section 21a toward a deeper part of the
screw hole 12b. The fixing screw 3 is a hexagon socket set screw,
and is tightened up until it is completely buried inside the screw
hole 12b. As a result, the front end portion 30 of the fixing screw
3 slightly projects from the screw hole 12b, and abuts on the flat
surface formed on the inner circumferential surface of the brush
case 2. Thus, the fixing screw 3 and the holder 12 are pressed to
each other in the inside of the circumferential wall part 21 of the
brush case 2 and in the radial direction thereof, so that the
holder 12 is pressed and immobilized against the inner
circumferential surface of the opening section 21a of the
circumferential wall part 21. In this state, the base end section
of the fixing screw 3 has been embedded in the screw hole 12b, and
the fixing screw 3 does not at all project from the outer
circumferential surface of the circumferential wall part 21.
[0042] When the polishing machine brush 10 thus having the
brush-like grinding stone 1 completely fixed to the brush case 2 is
used for polishing, the tip portions of the linear grinding members
11 are worn, and the projection dimension of the linear grinding
members 11 is reduced. In this case, the fixing screw 3 is eased,
and the holder 12 is then moved in the axial direction, so that the
projection dimension of the linear grinding members 11 is adjusted
to an appropriate dimension, which is, for example, several
millimeters to several tens of centimeters. The fixing screw 3 is
then tightened up again, so that the holder 12 is immobilized
inside the brush case 2.
Second Example of Brush-Like Grinding Stone
[0043] FIG. 2 is an illustration of a brush-like grinding stone
according to a second example of the present invention. Note that
the basic structure of a polishing machine brush of this example is
the same as in the mode illustrated in FIG. 1. Hence, common
reference signs are given to common components and descriptions
thereof are omitted.
[0044] While the linear grinding members 11 are held by the holder
12 in the form of the bundles 110 in the brush-like grinding stone
1 according to the first example, a plurality of linear grinding
members 11 is held by the holder 12 in the form of a single bundle
110 in this embodiment as illustrated in FIG. 2. Similarly to the
aspect described with reference to FIG. 1, the brush-like grinding
stone 1 and the polishing machine brush 10 that are thus structured
are also rotated about the rotational center axis line L with the
tips of the linear grinding members 11 pressed against a workpiece,
thereby being used to remove burrs generated during molding or
processing, or polish the surface of the workpiece.
Third Example of Brush-Like Grinding Stone
[0045] FIG. 3 is an illustration of a brush-like grinding stone
according to a third example of the present invention. Note that
the basic structure of a polishing machine brush of this example is
the same as in the mode illustrated in FIG. 1. Hence, common
reference signs are given to common components and descriptions
thereof are omitted.
[0046] The brush-like grinding stone 1 illustrated in FIG. 3 is a
tool for removing burrs inside cross-holes, and includes a
plurality of linear grinding members 11 held in the form of a
bundle 110 by the holder 12. The holder 12 includes a driving
connecting shaft 120 formed thereon that is extended in the
rotational center axis line L, and the driving connecting shaft 120
is coupled to an electric-powered rotation driving apparatus or the
like. Additionally, a portion extending from the holder 12 to the
base of the bundle 110 of the linear grinding members 11 is covered
with a heat-shrinkable tube 40.
[0047] The thus structured brush-like grinding stone 1 is used by
having the bundle 110 of the linear grinding members 11 inserted
into a cross-hole from the tip side thereof, and having the
brush-like grinding stone 1 rotated about the rotational center
axis line L while the above state is maintained. As a result, the
linear grinding members 11 are widened radially outward, thereby
being enabled to remove burrs generated in the cross-hole.
Linear Grinding Member
[0048] Here, the linear grinding members 11 used in the respective
brush-like grinding stones 1 of the first example, the second
example, and the first example are described. FIG. 4 is an
illustration schematically depicting a structure of each of the
linear grinding members 11 of the first example to which the
present invention is applied. FIG. 5 is an illustration that
depicts a twisted state of a composite yarn included in the linear
grinding member 11, where two inorganic filaments of the inorganic
filaments composing the composite yarn are illustrated as a solid
line and a two-dot chain line. FIG. 6 is an illustration
schematically depicting a structure of each of the linear grinding
members 11 of the second example to which the present invention is
applied. FIG. 7 is an illustration schematically depicting a
structure of each of the linear grinding members 11 of the third
example to which the present invention is applied. Note that, in
illustrating the cross sections of composite yarns 15 and the
linear grinding members 11 with the inorganic filaments represented
by respective circles 150 in FIG. 4, FIG. 6, and FIG. 7, the
inorganic filaments are enlarged more than the composite yarns 15
and the linear grinding members 11, and the numbers thereof are
illustratively smaller correspondingly. Although some of the
circles 150 representing the inorganic filaments are therefore
illustrated as being chipped off, there are no chipped-off
inorganic filaments in the composite yarns 15 and the linear
grinding members 11. For the linear grinding members 11 used in the
brush-like grinding stones 1 of the first example, the second
example, and the first example, a linear grinding member 11A having
a square cross-sectional shape as illustrated as the first example,
a linear grinding member 11B having a rectangular cross-sectional
shape as illustrated as the second example, or a linear grinding
member 11C having an elliptical cross-sectional shape as
illustrated as the third example is used.
First Example of Linear Grinding Member
[0049] As illustrated in FIG. 4, the linear grinding member 11A in
this example has a square cross-sectional shape in a direction
perpendicular to the axis line thereof.
[0050] The linear grinding member 11A of this example is hard to
bend and firm because of having the same dimension in the X and Y
directions of the cross section. Hence, the linear grinding member
11A is suitable for polishing a surface with few irregularities,
and a surface with no irregularities. Additionally, the linear
grinding member 11A exhibits sufficiently high firmness when the
projection dimension is long, therefore being suitable for removing
burrs inside a cross-hole, which requires high firmness.
Furthermore, since the linear grinding member 11A has the same
level of easiness to bend in the X and Y directions of the cross
section, the linear grinding member 11A makes regular motions
during processing. Consequently, using the linear grinding member
11A enables processing to be less prone to scratches and to provide
fine finish surface roughness. Thus, the linear grinding member 11A
is suitable for polishing, for example, surfaces for which finish
surface roughness is important.
[0051] Additionally, the linear grinding member 11A exerts an edge
effect because it is hard to bend in the diagonal directions. The
linear grinding member 11A exerts a high edge effect because it has
right-angled corners. Thus, the linear grinding member 11A has
excellent grindability.
[0052] Here, as illustrated in FIG. 5, the composite yarn 15 in the
linear grinding member 11A may have been twisted. In this case, the
composite yarn 15 in the linear grinding member 11A is twisted in
such a manner that a length dimension S of the linear grinding
member 11A corresponding to one turn of twisting is in the range of
1 cm to 4 cm. With the length dimension S of the linear grinding
member 11A corresponding to one turn of twisting set to 4 cm or
less, the effect of preventing longitudinal cracks of the linear
grinding member 11A can be obtained. With the length dimension S of
the linear grinding member 11A corresponding to one turn of
twisting set to 1 cm or more, the inorganic filaments can be
prevented from fuzzing because of the twisting.
Second Example of Linear Grinding Member
[0053] As illustrated in FIG. 6, the linear grinding member 11B in
this example has a rectangular cross-sectional shape in a direction
perpendicular to the axis line thereof.
[0054] In the linear grinding member 11B in this example, a
dimension in the thickness direction T (a direction along the short
sides) is smaller than a dimension in the width direction W (a
direction along the long sides). Hence, the linear grinding member
11B is easy to bend in the thickness direction T, and is hard to
break off. Thus, the linear grinding member 11B is suitable for
deburring, for example, a surface having a lot of irregularities on
a surface to be processed. Additionally, the linear grinding member
11B has a cross section thinner in the thickness direction than in
the width direction. Therefore, the tip thereof easily breaks, and
the self-sharpening action for generating a new cutting edge is
active. Furthermore, clogging is unlikely to occur because the
linear grinding member 11B is thin.
[0055] Additionally, the linear grinding member 11B has an edge
effect because it is hard to bend in a direction along the long
sides and the diagonal directions of the cross-section. The linear
grinding member 11B further has a high edge effect because it has
right-angled corners. Furthermore, the linear grinding member 11B
makes irregular motions during processing since degrees of easiness
to bend are different in the thickness direction and width
direction of the cross section thereof. Thus, the linear grinding
member 11B provides increased grinding performance because it makes
irregular motions and has an edge effect at the same time.
Therefore, the linear grinding member 11B easily adapts to
irregularities on a workpiece, thus being suitable for deburring
and surface polishing where excellent grindability is desired.
[0056] An aspect ratio (a value obtained by dividing a dimension in
the width direction W by a dimension in the thickness direction T)
of the linear grinding member 11B is in the range of 1.1 to 5.0.
More specifically, it has been found that, when having an aspect
ratio in the range of 1.1 to 5.0, the linear grinding member 11B is
less likely to bend in a direction along the long sides of the
cross section and exerts an edge effect. Here, the aspect ratio set
in the range of 2.0 to 5.0 is highly effective for the activeness
of the self-sharpening action, the degree of clogging prevention,
the irregularity of motions during processing, and the edge effect.
Alternatively, the aspect ratio set in the range of 1.1 to 1.9
slightly reduces the activity level of the self-sharpening action
and the degree clogging prevention; however, it results in
relatively regular motions during processing, so that a surface
finished with fine surface roughness is obtained.
[0057] Note that an adjustment such as increasing the aspect ratio
for higher grinding performance or decreasing the aspect ratio for
lower grinding performance can be made. However, the surface
roughness of a workpiece after processing tends to be rougher when
processing efficiency is increased with the aspect ratio increased,
and tends to be finer when processing efficiency is decreased with
the aspect ratio decreased.
[0058] Here, as illustrated in FIG. 5, the composite yarn 15 in the
linear grinding member 11B may have been twisted. When the aspect
ratio of the linear grinding member 11B is in the range of 1.1 to
1.9, the composite yarn 15 is twisted in such a manner that a
length dimension S of the linear grinding member 11B corresponding
to one turn of twisting is in the range of 1 cm to 4 cm. With the
length dimension S of the linear grinding member 11B corresponding
to one turn of twisting set to 4 cm or less, the effect of
preventing longitudinal cracks of the linear grinding member 11B
can be obtained. With the length dimension S of the linear grinding
member 11B corresponding to one turn of twisting set to 1 cm or
more, the inorganic filaments can be prevented from fuzzing because
of the twisting.
[0059] Otherwise, when the aspect ratio of the linear grinding
member 11B is in the range of 2.0 to 5.0, the length dimension S of
the linear grinding member 11B corresponding to one turn of
twisting is set in the range of 10 cm to 20 cm. With the length
dimension S of the linear grinding member 11B corresponding to one
turn of twisting set to 20 cm or less, the effect of preventing
longitudinal cracks of the linear grinding member 11B can be
obtained. With the length dimension S of the linear grinding member
11B corresponding to one turn of twisting set to 10 cm or more, the
inorganic filaments can be prevented from fuzzing because of the
twisting. More specifically, in the case of the linear grinding
member 11B having a cross-sectional shape the aspect ratio of which
is 2.0 or higher, twisting the composite yarn 15 more easily causes
the inorganic filaments to fuzz in the thickness direction than in
the case of the linear grinding member having a square
cross-sectional shape. In this example, however, a length dimension
of the linear grinding member 11B corresponding to one turn of
twisting is set larger than that of the one having a square
cross-sectional shape, which can prevent the inorganic filaments
from fuzzing.
Third Example of Linear Grinding Member
[0060] As illustrated in FIG. 7, the linear grinding member 11C in
this example has an elliptical cross-sectional shape in a direction
perpendicular to the axis line thereof.
[0061] The linear grinding member 11C in this example has a
dimension in the thickness direction T (a direction along the minor
axis) smaller than a dimension in the width direction W (a
direction along the major axis). Hence, the linear grinding member
11C easily bends in the thickness direction T, and is hard to break
off. Thus, the linear grinding member 11C is suitable for
deburring, for example, a surface having a lot of irregularities on
a surface to be processed. Additionally, the linear grinding member
11C has a cross section thinner in the thickness direction than in
the width direction. Therefore, the tip thereof easily breaks, and
the self-sharpening action for generating a new cutting edge is
active. Furthermore, clogging is unlikely to occur because the
linear grinding member 11C is thin.
[0062] Additionally, the linear grinding member 11C has an edge
effect because it is hard to bend in a direction along the major
axis of the cross-section. Furthermore, the linear grinding member
11C has different degrees of easiness to bend in the thickness
direction and width direction of the cross section, and
consequently makes irregular motions during processing. Thus, the
linear grinding member 11C provides increased grinding performance
because it makes irregular motions and has an edge effect at the
same time. Therefore, the linear grinding member 11C easily adapts
to irregularities on a workpiece, thus being suitable for deburring
and surface polishing where excellent grindability is desired.
[0063] An aspect ratio (a value obtained by dividing a dimension in
the width direction W by a dimension in the thickness direction T)
of the linear grinding member 11C is in the range of 1.1 to 5.0.
More specifically, it has been found that, with the aspect ratio in
the range of 1.1 to 5.0, the linear grinding member 11C is harder
to bend in a direction along the major axis of the cross section
and exerts an edge effect. Here, the aspect ratio set in the range
of 2.0 to 5.0 is highly effective for the activeness of the
self-sharpening action, the degree of clogging prevention, the
irregularity of motions during processing, and the edge effect. The
aspect ratio otherwise set in the range of 1.1 to 1.9 slightly
reduces the activeness of the self-sharpening action and the degree
of clogging prevention; however, it results in relatively regular
motions during processing, so that a finished surface with fine
surface roughness is obtained.
[0064] Furthermore, the linear grinding member 11C having an
elliptical shape does not leaving damages such as scratches in
processing of a workpiece because of having no corners in the cross
section, and is therefore usable for, for example, surface
polishing where fine surface roughness is desired.
[0065] Note that an adjustment such as increasing the aspect ratio
for higher grinding performance or decreasing the aspect ratio for
lower grinding performance can be made. However, the surface
roughness of a workpiece after processing tends to be rougher when
processing efficiency is increased with the aspect ratio increased,
and tends to be finer when processing efficiency is decreased with
the aspect ratio decreased.
[0066] Here, as illustrated in FIG. 5, the composite yarn 15 in the
linear grinding member 11C may have been twisted. When the aspect
ratio of the linear grinding member 11C is in the range of 1.1 to
1.9, the composite yarn 15 is twisted in such a manner that a
length dimension S of the linear grinding member 11C corresponding
to one turn of twisting is in the range of 1 cm to 4 cm. When the
aspect ratio of the linear grinding member 11C is in the range of
2.0 to 5.0, the length dimension S of the linear grinding member
11C corresponding to one turn of twisting is in the range of 10 cm
to 20 cm. In this manner, the same effects as those in the case of
the linear grinding member 11B having a rectangular cross-sectional
shape can be obtained.
First Example of Method for Manufacturing Linear Grinding
Member
[0067] FIG. 8 is an illustration depicting a first example of a
method for manufacturing a linear grinding member, where (a) and
(b) of FIG. 8 illustrate an impregnation step and steps following
the impregnation step.
[0068] In manufacturing the linear grinding member 11, firstly, the
composite yarn 15 of inorganic filaments is impregnated with an
uncured resin binder 16 in the impregnation step illustrated in (a)
of FIG. 8. Examples of resin that can be used as the resin binder
16 include: thermosetting resin such as epoxy resin and phenolic
resin; silicone resin; and thermoplastic resin such as polyester
resin, polypropylene resin, and polyamide resin. In this
embodiment, the composite yarn 15 is supplied in a state wound
around a cylindrical or columnar bobbin 51, and the resin binder 16
has been reserved in a resin binder vessel 53. After being drawn
out from the bobbin 51 while being wound up around a bobbin 52, the
composite yarn 15 moves on while being guided by a guide member 54
such as a roller placed inside a resin binder container 53, and
guide members 55 and 56 such as rollers placed outside the resin
binder container 53. The composite yarn 15 is immersed with the
resin binder 16 reserved in the resin binder container 53, thus
being impregnated with the resin binder 16, before it is wound up
around the bobbin 52. The composite yarn 15 impregnated with the
resin binder 16 is wound around the bobbin 52 without overlapping
itself.
[0069] As illustrated in (b) of FIG. 8, the impregnated composite
yarn 15 wound around the bobbin 52 is then subjected to a shaping
step where the cross-sectional shape thereof is shaped when passing
through a die 61, and then subjected to a resin-curing step where
the impregnated composite yarn 15 is put in a heating furnace 62
where the resin binder 16 is cured. As a result, the linear
grinding member 11 having the composite yarn 15 of a plurality of
inorganic filaments stiffened with the resin binder 16 is obtained.
The thus obtained linear grinding member 11 is cut into pieces of a
predetermined dimension after the resin-curing step. Alternatively,
the linear grinding member 11 may be cut into pieces of a
predetermined dimension after being wound around another bobbin
(not illustrated).
[0070] Here, the die 61 has a passage (not illustrated) formed
therein through which the impregnated composite yarn 15 passes, and
the passage opens at opposite end surfaces of the die 61. Hence,
opening sections 610 of the passage are provided in the end
surfaces of the die 61, and, when passing through the die 61, the
composite yarn 15 is shaped so that the cross-sectional shape
thereof can be a shape corresponding to the shape of the passage
and the opening sections 610. As a result, the linear grinding
member 11 having a cross-sectional shape corresponding to the shape
of the passage of the die 61 and the opening sections 610 is
obtained.
[0071] More specifically, when the shape of the opening sections
610 is square, the linear grinding member 11 (linear grinding
member 11A) having a square cross-sectional shape is obtained as
illustrated in FIG. 4. When the shape of the opening sections 610
is rectangular, the linear grinding member 11 (linear grinding
member 11B) having a rectangular cross-sectional shape is obtained
as illustrated in FIG. 6. Similarly, when the shape of the opening
sections 610 is elliptical, the linear grinding member 11 (linear
grinding member 11C) having an elliptical cross-sectional shape is
obtained as illustrated in FIG. 7. Note that, in the die 61, the
passage may be formed as any one of a through-hole and a groove
that opens on a side surface of the die 61.
[0072] As described above, in this embodiment, when the linear
grinding member 11 is manufactured, the cross-sectional shape of
the composite yarn 15 is shaped in such a manner that: the
composite yarn 15 is impregnated with the uncured resin binder 16
in the impregnation step; and thereafter the composite yarn 15
impregnated with the resin binder 16 is passed through the die 61
in the shaping step before the resin binder 16 is cured in the
resin-curing step. Thus, the cross-sectional shape of the linear
grinding member 11 can be easily controlled.
Second Example of Method for Manufacturing Linear Grinding
Member
[0073] FIG. 9 is an illustration depicting a second example of a
method for manufacturing a linear grinding member, where (a) and
(b) of FIG. 9 illustrate an impregnation step and steps following
the impregnation step. Note that the basic configuration of the
mode illustrated in FIG. 9 is the same as in the mode described
with reference to FIG. 8. Hence, common reference signs are given
to common components and descriptions thereof are omitted.
[0074] In the method for manufacturing the linear grinding member 1
in this embodiment, when the linear grinding member 11 is
manufactured, firstly, the composite yarn 15 of inorganic filaments
is impregnated with the uncured resin binder 16 in the impregnation
step illustrated in (a) of FIG. 9 as in the case of the
impregnation step described with reference to (a) of FIG. 8. In
this embodiment, the composite yarn 15 is supplied in a state wound
around the cylindrical or columnar bobbin 51. Before being wound up
around the bobbin 52, the composite yarn 15 is immersed with the
resin binder 16 reserved in the resin binder container 53 to be
impregnated with the resin binder 16.
[0075] Here, the bobbin 51 is provided with a drive unit 59 that
rotates the bobbin 51 about an axis line P extending in a direction
in which the composite yarn 15 is fed. When the impregnation step
is performed, the drive unit 59 rotates the bobbin 51 about the
axis line P synchronously with feeding of the composite yarn 15.
Consequently, the composite yarn 15 is twisted as schematically
illustrated in FIG. 5. The twisting is such that, when the linear
grinding member 11 having a square cross-sectional shape as
illustrated in FIG. 5 is manufactured, a length dimension S of the
linear grinding member corresponding to one turn of twisting is set
in the range of 1 cm to 4 cm. Otherwise, when the linear grinding
member 11 having a rectangular or elliptical cross-sectional shape
as illustrated in FIG. 6 or FIG. 7 is manufactured, a length
dimension S of the linear grinding member corresponding to one turn
of twisting is set in the range of 1 cm to 4 cm or 10 cm to 20
cm.
[0076] As illustrated in (b) of FIG. 9, the impregnated composite
yarn 15 wound around the bobbin 52 is then subjected to a shaping
step where the cross-sectional shape thereof is shaped when passing
through a die 61, and then subjected to a resin-curing step where
the impregnated composite yarn 15 is put in a heating furnace 62
where the resin binder 16 is cured. As a result, the linear
grinding member 11 having the composite yarn 15 of a plurality of
inorganic filaments stiffened with the resin binder 16 is obtained.
This linear grinding member 11 is cut into pieces of a
predetermined dimension after the resin-curing step. Alternatively,
the linear grinding member 11 may be cut into pieces of a
predetermined dimension after being wound around another bobbin
(not illustrated).
[0077] Here, the die 61 has an opening section 610 through which
the already impregnated composite yarn 15 passes, whereby, when
passing through the die 61, the composite yarn 15 is shaped to have
a cross-sectional shape corresponding to the shape of the opening
section 610. As a result, the linear grinding member 11 having a
square, rectangular or elliptical cross-sectional shape is
obtained.
[0078] As described above, in this embodiment, when the linear
grinding member 11 is manufactured, the cross-sectional shape of
the composite yarn 15 is shaped in such a manner that: the
composite yarn 15 is impregnated with the uncured resin binder 16
in the impregnation step; and thereafter the composite yarn 15
impregnated with the resin binder 16 is passed through the die 61
in the shaping step before the resin binder 16 is cured in the
resin-curing step. Thus, the cross-sectional shape of the linear
grinding member 11 can be easily controlled. Hence, the brush-like
grinding stone 1 including linear grinding members each having a
cross-sectional shape suitable for a purpose such as surface
polishing or deburring of a cross-hole can be obtained.
[0079] Additionally, in this embodiment, a twisting step of
twisting the composite yarn 15 is performed before the impregnation
step, and inorganic filaments become tangled in the composite yarn
15 as a result of the twisting of the composite yarn 15. Thus, it
is easier to control the cross-sectional shape of the linear
grinding member 11 than in a case where another composite yarn 15
in which the inorganic filaments extend parallel to one another is
used.
[0080] Here, when the linear grinding member 11 has a square
cross-sectional shape, a length dimension of the linear grinding
member 11 corresponding to one turn of twisting is set in the range
of 1 cm to 4 cm. Since the length dimension of the linear grinding
member 11 corresponding to one turn of twisting is thus not more
than 4 cm, effects of the twisting can be exerted. Additionally,
the length dimension of the linear grinding member 11 corresponding
to one turn of twisting is 1 cm or more, whereby the inorganic
filaments can be prevented from fuzzing because of the
twisting.
[0081] Otherwise, when the linear grinding member 11 has a
rectangular or elliptical cross-sectional shape, a length dimension
of the linear grinding member 11 corresponding to one turn of
twisting is set in the range of 1 cm to 4 cm if the aspect ratio
thereof is in the range of 1.1 to 1.9. With the length dimension S
of the linear grinding member 11C corresponding to one turn of
twisting set to 4 cm or less, the effect of preventing longitudinal
cracks of the linear grinding member 11 can be obtained as in the
case of the linear grinding member 11 that has a square
cross-sectional shape. With the length dimension S of the linear
grinding member 11C corresponding to one turn of twisting set to 1
cm or more, the inorganic filaments can be prevented from fuzzing
because of the twisting, as in the case of the linear grinding
member 11 that has a square cross-sectional shape.
[0082] Furthermore, when the linear grinding member 11 has a
rectangular or elliptical cross-sectional shape, a length dimension
of the linear grinding member 11 corresponding to one turn of
twisting is set in the range of 10 cm to 20 cm if the aspect ratio
thereof is in the range of 2.0 to 5.0. More specifically, for the
linear grinding member 11 that has an aspect ratio of 2.0 or
higher, a length dimension of the linear grinding member 11
corresponding to one turn of twisting is set larger than for the
linear grinding member 11 that has a square cross-sectional shape.
Hence, the inorganic filaments in the composite yarn 15 become
tangled both in the thickness direction and in the width direction
even when the aspect ratio is so large as 2.0 or higher. Thus, it
is easier to control the cross-sectional shape of the linear
grinding member 11 than in a case where another composite yarn 15
in which the inorganic filaments extend parallel to one another is
used. Additionally, when the linear grinding member 11 having a
rectangular or elliptical cross-sectional shape the aspect ratio of
which is 2.0 or higher is twisted, the inorganic filaments tend to
fuzz in the thickness direction. In this example, however, a length
dimension of the linear grinding member 11 corresponding to one
turn of twisting is set larger than that of another linear grinding
member 11 having a square cross-sectional shape, which can prevent
the inorganic filaments from fuzzing. In this embodiment,
particularly for the linear grinding member 11 having a rectangular
or elliptical cross-sectional shape the aspect ratio of which is
2.0 or higher, the length dimension of the linear grinding member
11 corresponding to one turn of twisting is not more than 20 cm,
whereby effects of the twisting can be exerted.
[0083] Additionally, the length dimension of the linear grinding
member 11 corresponding to one turn of twisting is 10 cm or more,
whereby the inorganic filaments can be prevented from fuzzing
because of the twisting.
[0084] Note that, although the resin-curing step follows the
shaping step in the first example and the second example, the
shaping step and the resin-curing step may be concurrently
performed with a heating unit provided to the die 61.
[0085] Additionally, each of the first example and the second
example may further include, after the shaping step of shaping the
cross-sectional shape of the composite yarn 15 by passing the
composite yarn 15 through the die 61, a size adjustment step of
cutting out the shaped linear grinding member into pieces having a
cross-sectional shape of a predetermined size.
Third Example of Method for Manufacturing Linear Grinding
Member
[0086] Although the cross-sectional shape of the composite yarn 15
is shaped by passing the composite yarn 15 through the die 61 in
each of the first example and the second example, each of these
examples may exclude the shaping step of passing the composite yarn
15 through the die 61 to shape the cross-sectional shape thereof,
and include, after the impregnation step and the resin-curing step
are continuously performed, a polishing shaping step of polishing
an outer circumferential surface of the composite yarn 15 to shape
the cross-sectional shape thereof into a square, rectangle, or
ellipse.
* * * * *