WO2015026762A1

WO2015026762A1 - Wheel for grinding belt, grinding wheel, grinding method, and article including object ground by grinding method

Info

Publication number: WO2015026762A1
Application number: PCT/US2014/051590
Authority: WO
Inventors: Michihiro Yamahara
Original assignee: 3M Innovative Properties Company
Priority date: 2013-08-23
Filing date: 2014-08-19
Publication date: 2015-02-26
Also published as: TW201532741A; JP2015039754A; JP6223062B2

Abstract

It is an object that the surface of the grinding belt be more effectively used, while maintaining the ease of fitting the grinding belt. The wheel for a grinding belt according to embodiment includes a plurality of arc-shaped hard members that form the outer circumferential surface on which the endless grinding belt can be fitted, and an air tube disposed to the inside in the radial direction of the plurality of hard members. Each of the hard members is moved to the outside in the radial direction by inflating the air tube with air.

Description

WHEEL FOR GRINDING BELT, GRINDING WHEEL, GRINDING METHOD, AND ARTICLE INCLUDING OBJECT GROUND BY GRINDING METHOD

FIELD OF THE INVENTION

[0001] A wheel for a grinding belt, a grinding wheel, a grinding method, and an article including an object ground by the grinding method.

BACKGROUND

[0002] Grinding wheels for grinding metal members and the like are conventionally known. For example, Patent Document 1 discloses a wheel assembly that includes a pneumatically inflated tire that is engaged with a grinding belt by pressure. The grinding belt is placed on the deflated tire, and the grinding belt is fixed to the tire by inflating the tire with air. When this wheel assembly is fitted to a shaft and rotated, the fitted grinding belt grinds metal or the like. Patent document 1 : Specification of U.S. Patent No. 7824248.

SUMMARY

Problems to be Solved

[0003] By using the wheel assembly disclosed in Patent Document 1, the grinding belt can be simply fitted to the tire in the deflated state, and thereafter the grinding belt can be securely fixed to the wheel by inflating the tire. However, the surface of a tire (substantially a tube) that has been inflated with air is generally not flat. Therefore, when the grinding belt is fitted to the surface thereof, it is difficult for the entire width of the grinding belt to contact the object to be ground, and as a result it is not possible to effectively use the grinding surface of the grinding belt.

[0004] Therefore it is desirable that the surface of the grinding belt be more effectively used, while maintaining the ease of fitting the grinding belt.

[0005] The wheel for a grinding belt according to one aspect of the present invention includes a plurality of arc-shaped hard members that form the outer circumferential surface on which an endless grinding belt can be fitted, and an air tube disposed to the inside in the radial direction of the plurality of hard members, and each of the hard members is moved to the outside in the radial direction by inflating the air tube with air.

[0006] In this aspect, each of the plurality of hard members is moved to the outside in the radial direction by inflating the air tube. Therefore, the endless grinding belt can be easily placed on the outer circumferential surface before inflation, and thereafter by inflating the air tube it is possible to securely fix the grinding belt to the outer circumferential surface by the pressure. Also, the outer circumferential surface of the wheel for a grinding belt is formed from hard members, so the grinding belt can be fitted along the outer circumferential surface regardless of the shape of the inflated air tube. Therefore, the grinding belt can be set along the required shape of the outer circumferential surface, and therefore the grinding surface can be effectively used. In this way, in the aspect as described above, it is possible to effectively use the surface of the grinding belt while maintaining the ease of fitting the grinding belt.

[0007] According to this aspect of the present invention, it is possible to effectively use the surface of the grinding belt while maintaining the ease of fitting the grinding belt.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of a grinding wheel according to an embodiment;

FIG. 2 is a perspective view of a wheel for a grinding belt according to the embodiment; FIG. 3 is a cross-sectional view at the line III-III in FIG. 2;

FIG. 4 is a partial enlarged view showing the positional relationship between a hub and wide shoes;

FIG. 5 is a perspective view of a mechanical stop;

FIG. 6 is a partial enlarged view showing fitting of the wide shoes;

FIG. 7 is a cross-sectional view showing the variation in the external diameter of the wheel for the grinding belt;

FIG. 8 is a partial enlarged view showing the state in which the wide shoes are gathered to the hub side; and

FIG. 9 is a partial enlarged view showing the state in which the wide shoes have moved to the outer circumferential side.

DETAILED DESCRIPTION

[0009] An embodiment of the present invention is described in detail below while referencing the accompanying drawings. In the explanations of the drawings, identical or equivalent elements are labeled with the same symbols, and redundant explanations will be omitted.

[0010] First, the structure of a wheel for a grinding belt (hereafter simply referred to as

"wheel") 1 according to an embodiment is described with reference to FIGS. 1 to 4. The wheel 1 is a component that constitutes a part of a grinding machine (not shown on the drawings), and as shown in FIG. 1 , has the role of supporting an endless grinding belt (in this Specification simply referred to as "grinding belt") 70. A grinding wheel can be obtained by fitting the grinding belt 70 to the wheel 1, and the grinding wheel shown in FIG. 1 can be supplied as a product. In the example in FIG. 1, a cylindrical thin cushion 80 is disposed on the outer circumferential surface of the wheel 1, and the grinding belt 70 is disposed on the cushion 80, but the cushion 80 can be omitted.

[0011] A through hole 11 is formed in the center of the wheel 1 through which a shaft

(not shown on the drawings) of the grinding machine passes, and the wheel 1 is fixed to the shaft passing through it. There is no limitation on the method of fixing the wheel 1. For example, the wheel 1 may be fixed by fitting a nut to a male screw formed on one end of the shaft. There is no limitation on the type of grinding machine, and the wheel 1 can be applied to any grinding machine having a shaft.

[0012] In this Specification, the direction along the rotational axis A of the wheel 1 shown in FIG. 1 (the direction that the shaft that passes through the through hole 11 extends) is defined as the "width direction" of the wheel 1, and the side surface of the wheel 1 in the width direction is simply referred to as "side surface".

[0013] If from the state shown in FIG. 1 the grinding belt 70 and the cushion 80 are removed, and, covers 12 fitted to the two side surfaces of the wheel 1 are removed, the wheel 1 has the external appearance shown in FIG. 2. As shown in FIG. 2, the wheel 1 includes a hub 20 on which the through hole 11 is formed, and a plurality of arc-shaped wide shoes 30 fitted to the outer circumference of the hub 20. The outer circumferential surface 13 of the wheel 1 is formed by the wide shoes 30. Each wide shoe 30 is fitted to the hub 20 using a fitting referred to as a mechanical stop 40. The hub 20, the wide shoes 30, and the mechanical stop 40 are made from a material such as metal or resin or the like, but there is no specific limitation on the material provided it is hard.

[0014] The hub 20 is the inside portion of the wheel 1, and the through hole 11 is formed in the center thereof along the width direction. In this embodiment, the diameter of the through hole 11 is either the same as the external diameter of the shaft, or is smaller than the external diameter of the shaft to such an extent that the shaft can pass through it. However, if an adapter (not shown on the drawings) is used to fix the wheel 1 to the shaft, the diameter of the through hole 11 may be larger than the external diameter of the shaft. A plurality of screw holes 22 for fitting the mechanical stops 40 is formed on the two side surfaces of the hub (see FIG. 4).

[0015] As shown in FIG. 3, the outer circumferential side of the hub 20 is open, and a space is formed from this opening extending to the inner circumferential side of the hub 20. The width of the outer circumferential side of this space is wide, and therefore the cross-sectional shape of the space along the width direction is an approximately T-shape. A circular air tube 50 is fitted into the space. The cross-section of the air tube 50 along the width direction is an approximately T-shape in accordance with the space. The air tube 50 is connected to a valve 21 for injecting air, provided close to the through hole 11 in one side surface of the hub 20, and the air tube 50 is inflated with the air injected via the valve 21.

[0016] The wide shoe 30 is an arc-shaped hard member that forms the outer circumferential surface 13 of the wheel 1. The outer circumferential end surface 31 of each wide shoe 30 is formed in a circular arc shape with a uniform curvature, and by connecting the plurality of wide shoes 30 along the circumferential direction, the circular outer circumferential surface 13 is formed as shown in FIG. 2. In this embodiment, the outer circumferential surface 13 is formed by eight wide shoes 30 whose central angle of the outer circumference is 45°, but the number of wide shoes may be set as desired, for example the outer circumferential surface 13 of the wheel 1 may be formed by two, four, or nine wide shoes 30. [0017] As shown in FIG. 3, the inner circumferential end surface 32 of each of the wide shoes 30 has a V-shaped depression. The width of the inner circumferential end surface 32 is substantially same as the width of the outer circumferential end surface 51 of the air tube 50. As shown in FIG. 4, there are two circular grooves formed concentrically with the outer circumferential end surface 31 (in other words, extending along the circumferential direction) on the two side surfaces of the wide shoes 30, so when the eight wide shoes 30 are connected, two circular grooves are formed in each side surface of the wheel 1. A rubber ring (elastic member) 60 is fitted into the groove on the outer side 33 (hereafter referred to as the "outer groove 33"). On the other hand, a portion of the mechanical stop 40 is inserted into the groove on the inside 34 (hereafter referred to as the "inner groove 34"). The outer groove 33 into which the ring 60 is fitted is deeper than the inner groove 34. A portion of the wall that separates the outer groove 33 and the inner groove 34 is depressed (depression portion 35) in accordance with the shape of a stopper 42 of the mechanical stop 40 that is described later.

[0018] The mechanical stop 40 is formed as a rectangular plate overall, as shown in

FIG. 5. Two screw holes 41 that are used for fixing the mechanical stop 40 to the hub 20 are provided in a region on the surface facing the side surface of the wheel 1 corresponding to the hub 20 during installation, and a cross-shaped stopper 42 is provided in a region of the surface corresponding to the wide shoe 30. A protruding portion 42a of the stopper 42 that extends in the short direction of the mechanical stop 40 corresponds to the inner groove 34. The width of the protruding portion 42a (the length in the long direction of the mechanical stop 40) is smaller than the width of the inner groove 34.

[0019] Next, the method of assembly of the wheel 1 is described, also using FIG. 6.

The operator first arranges each of the wide shoes 30 so that the depression portion 35 is disposed on the extension line that passes through the two screw holes 22 of the hub 20 that are aligned along the radial direction, as shown in FIG. 4. As a result of this process, the circular outer groove 33 and the inner groove 34 are formed. Next, the operator fits the ring 60 into the outer groove 33 on one of the side surfaces. Next, the operator fits the mechanical stop 40 to the hub 20 as shown in FIG. 6, by passing screws through the screw holes 22 in the hub 20 and the screw holes 41 in the mechanical stop 40. The operator carries out this operation for all the mechanical stops 40, and in this way the fitting operation on one side surface of the wheel 1 is completed. The operator fits the ring 60 and fixes all of the mechanical stops 40 to the other side surface of the wheel 1. Finally the operator fixes the covers 12 to both side surfaces, and in this way assembly of the wheel 1 is complete.

[0020] Each wide shoe 30 is fixed so that it cannot move in the circumferential direction due to the stopper 42 fitted to the depression portion 35. Each wide shoe 30 can be moved to the outside in the radial direction by inflating the air tube 50 which is disposed on the inside in the radial direction of the wide shoe 30. However, the protruding portion 42a of the stopper 42 is inserted into the inner groove 34 as shown in FIG. 6, so the movement is limited by the protruding portion 42a. Therefore the external diameter of the wheel 1 can vary within the range Rl or more and R2 or less, as shown in FIG. 7. The minimum diameter Rl is set smaller than the internal diameter of the grinding belt 70, and the maximum diameter R2 is set taking into consideration fixing the grinding belt 70.

[0021] Next, a method of grinding using the wheel 1 is described using FIGS. 8 and 9.

First, the operator fixes the wheel 1 to the shaft. In this case the air tube 50 is deflated, so the wide shoes 30 are displaced towards the hub 20 side by the elastic force of the ring 60, and the protruding portions 42a contact the wall on the outer circumferential side of the inner groove 34 as shown in FIG. 8. At this time the external diameter of the wheel 1 is the minimum value Rl .

[0022] Next, the operator places the grinding belt 70 on the outer circumferential surface 13 of the wheel 1 (placement process). In this embodiment, the operator first places the cushion 80 on the outer circumferential surface 13, then places the grinding belt 70 on the cushion 80. Moreover, as stated above the cushion 80 is not essential, so the operator may directly fit the grinding belt 70 onto the outer circumferential surface of the wheel 1, or may directly fit a grinding belt provided with a cushion layer on the inner circumferential surface thereof directly onto the wheel 1 , or may provide a cushion layer on the outer circumferential end surface 31 of the wide shoe 30 of the wheel 1.

[0023] Also, the operator may fit the wheel 1 to the shaft after fitting the grinding belt

70 to the wheel 1.

[0024] Next, the operator connects an air supply device such as an air pump or the like to the valve 21, and inflates the air tube 50 by injecting air into the air tube 50 (inflating process). When the inflating force exceeds the elastic force of the ring 60, the outer circumferential end surface 51 of the air tube 50 presses each wide shoe 30 to the outside, and therefore each wide shoe 30 moves to the outside in the radial direction of the wheel 1, as shown in FIG. 7. In this way, the wheel 1 applies sufficient pressure to the grinding belt 70 from the inside via the outer circumferential surface 13, and the grinding belt 70 is securely fixed onto the outer circumferential surface 13 by the pressure. In this case, the internal pressure of the air tube 50 when it is inflated is higher than the surrounding air pressure by, for example, 0.1 to 0.25 MPa, but the pressure difference is not limited to these values.

[0025] Next, the operator operates a grinding machine to rotate the wheel 1, and grinds the target object by bringing the grinding belt 70 into contact with the object to be ground (grinding process). Then, the ground object is supplied as an article as it is, or it is supplied as a part of an article.

[0026] It is conceivable that depending on the circumstances the grinding belt 70 fitted to the wheel 1 might extend slightly. However, each wide shoe 30 will be moved further to the outside in accordance with the extension of the grinding belt 70 by the inflated air tube 50, so the outer circumferential surface 13 of the wheel 1 continues to securely fix the grinding belt 70. As a result, it is possible to use a single grinding belt 70 for a long period of time (in other words, efficiently). As shown in FIG. 9, each wide shoe 30 can move to the outside in the radial direction until the protruding portion 42a contacts the wall of the inner circumferential side of the inner groove 34 (in other words, until the external diameter of the wheel 1 is the maximum value R2), so the extension of the grinding belt 70 can be followed within this range.

[0027] If the grinding force of the grinding belt 70 is reduced, the operator may replace the grinding belt 70 after releasing the air within the air tube 50. When the air within the air tube 50 is released, each wide shoe 30 is moved to the inside in the radial direction by the elastic force of the ring 60, and the external diameter of the wheel 1 returns to the minimum value Rl. The method of fitting a new grinding belt 70 is as described above. In this way, the operator can simply replace the grinding belt 70. Also, it is sufficient for the operator to replace the grinding belt 70 when the grinding force is reduced, so resources are conserved compared with the case that the whole grinding wheel is replaced.

[0028] As described above, the wheel for a grinding belt according to one aspect of the present invention includes a plurality of arc-shaped hard members that form the outer circumferential surface on which an endless grinding belt can be fitted, and an air tube disposed to the inside in the radial direction of the plurality of hard members, and each of the hard members is moved to the outside in the radial direction by inflating the air tube with air.

[0029] Also, the grinding wheel according to one aspect of the present invention includes the wheel for a grinding belt as described above and a grinding belt.

[0030] Also, the grinding method according to one aspect of the present invention is a method of grinding using a wheel for a grinding belt, and includes a placement process of placing an endless grinding belt on an outer circumferential surface of a wheel for a grinding belt that includes a plurality of arc-shaped hard members that form the outer circumferential surface, and an air tube disposed to the inside in the radial direction of the plurality of hard members; an inflating process of moving each of the hard members to the outside in the radial direction by inflating the air tube with air after placing the grinding belt on the outer circumferential surface; and a grinding process of grinding an object using the grinding belt that has been fixed onto the outer circumferential surface in the inflating process.

[0031] Also, the article according to one aspect of the present invention includes an object that has been ground by the grinding method as described above.

[0032] In these aspects, each of the plurality of hard members is moved to the outside in the radial direction by inflating the air tube. Therefore, the endless grinding belt can be easily placed on the outer circumferential surface before inflation, and thereafter by inflating the air tube it is possible to securely fix the grinding belt to the outer circumferential surface by the pressure. Also, the outer circumferential surface of the wheel for a grinding belt is formed from hard members, so the grinding belt can be fitted along the outer circumferential surface regardless of the shape of the inflated air tube. Therefore, the grinding belt can be set along the required shape of the outer circumferential surface, and therefore the grinding surface can be effectively used. In this way, in the aspects as described above, it is possible to effectively use the surface of the grinding belt while maintaining the ease of fitting the grinding belt.

[0033] Also, the hard members are pressed to the outside in the radial direction by inflating the air tube with positive internal pressure, so even if the grinding belt extends the hard members are moved further to the outside by the inflation pressure in accordance with the extension of the grinding belt. Therefore, the grinding belt can continue to be securely fixed by the outer circumferential surface of the wheel.

[0034] In another aspect of the present invention, the inner circumferential end surface of the hard members in contact with the inflated air tube may be formed in a tapered shape. In this case, the inflated air tube is guided to the center in the width direction of the hard members, so the hard members can be pressed straight to the outside in the radial direction, and as a result the grinding belt can be securely fixed over the whole outer circumferential surface.

[0035] In another aspect of the present invention, the width of the outer circumferential end surface of the air tube and the width of the inner circumferential end surface of the hard members may be substantially the same. In this case, the air tube contacts the entire inner circumferential end surface of the hard members, so the hard members can be pressed straight to the outside in the radial direction, and as a result the grinding belt can be securely fixed to the entire outer circumferential surface.

[0036] In another aspect of the present invention, an elastic member may be further provided that moves each of the hard members to the inside in the radial direction when the air has been released from inside the air tube. In this case, the operator does not have to return the hard members to their original position, and as a result the ease of use of the grinding wheel is improved.

[0037] In another aspect of the present invention, the elastic member may be a rubber ring that is fitted around the plurality of hard members. By using such a ring, it is possible to simply construct a mechanism that moves each of the hard members to the inside in the radial direction.

[0038] In another aspect of the present invention, each hard member is fitted to the hub by a fitting (mechanical stop), a groove that extends in the circumferential direction is formed in each hard member, a protruding portion is formed extending along the circumferential direction on each fitting, and the movement of each hard member along the radial direction is restricted by the protruding portion inserted into the groove. In this case, the fitting also plays the role of restricting the movement of the hard member, and therefore it is possible to reduce the number of components of the wheel for the grinding belt, and therefore to reduce the manufacturing cost.

[0039] The present invention was described in detail above based on embodiments thereof. However, the present invention is not limited to the above embodiments. Various modifications of the present invention are possible within a scope that does not deviate from the gist thereof. [0040] In the embodiment as described above, the inner circumferential end surface of the wide shoe 30 has a V-shaped depression, but the shape of the end surface is not limited to this. For example, the inner circumferential end surface may be formed by inclining the end surfaces on the two sides towards the center in a tapered shape, and making the center portion flat along the width direction of the wheel. Also, the inner circumferential end surface may have a U-shaped depression. Alternatively, the end surface may be formed flat, without providing a taper-shaped depression in the inner circumferential end surface of the hard members as in these examples.

[0041] In the embodiments described above, the width of the outer circumferential end surface 51 of the air tube 50 and the width of the inner circumferential end surface 32 of the wide shoe 30 are substantially the same, but their widths may be different from each other. In other words, the width of the outer circumferential end surface 51 of the air tube 50 may be larger than the width of the inner circumferential end surface 32 of the wide shoe 30, or it may be smaller.

[0042] In the embodiments described above, the ring 60 is provided as the elastic member, but the member for moving the outer circumferential surface of the wheel to the inside in the radial direction is not limited to this, for example the wide shoes 30 may be fixed to the hub 20 via tension springs. Alternatively, the elastic member such as the ring 60 or tension spring or the like may be omitted.

[0043] In the embodiments as described above, mechanical stops 40 were used to fit the wide shoes 30 to the hub 20, but there is no limitation on the configuration of the fitting. Accordingly, any configuration other than the assembly of the inner groove 34 and the protruding portion 42a may also be adopted as the mechanism for restricting the movements in the radial direction of the wide shoes 30. For example, the elastic member such as the ring 60 or the tension spring or the like may also have the role of restricting the movement in the radial direction of the hard members.

REFERENCE NUMERALS

[0044]

I Wheel

I I Through-hole

13 Outer circumferential surface

20 Hub

21 Valve

30 Wide shoe (hard member)

31 Outer circumferential end surface of wide shoe

32 Inner circumferential end surface of wide shoe

33 Outer groove

34 Inner groove

40 Mechanical stop (fitting)

42 Stopper

42a Protruding portion

50 Air tube

51 Outer circumferential end surface of air tube

60 Ring

70 Grinding belt

80 Cushion

Claims

Claims;

1. A wheel for a grinding belt, comprising: a plurality of arc-shaped hard members that form an outer circumferential surface on which an endless grinding belt is fitted; and an air tube disposed to be inside in the radial direction of the plurality of hard members, wherein each of the hard members is moved to the outside in the radial direction by inflating the air tube with air.

2. The wheel for a grinding belt according to claim 1, wherein the inner circumferential end surface of the hard members that contacts the inflated air tube is depressed in a tapered shape.

3. The wheel for a grinding belt according to claim 2, wherein the width of the outer circumferential end surface of the air tube is substantially equal to the width of the inner circumferential end surface of the hard members.

4. The wheel for a grinding belt according to any one of claims 1 to 3, further comprising an elastic member that moves each of the hard members to the inside in the radial direction when the air is released from inside the air tube.

5. The wheel for a grinding belt according to claim 4, wherein the elastic member is a rubber ring that is fitted to the plurality of hard members.

6. The wheel for a grinding belt according to any one of claims 1 to 5, wherein each of the hard members is fitted to a hub by a fitting,

a groove is formed in each of the hard members extending along the circumferential direction,

a protruding portion is formed extending along the circumferential direction on each fitting, and

the movement of each hard member along the radial direction is restricted by the protruding portion inserted into the groove.

7. A grinding wheel, comprising: a wheel for a grinding belt according to any one of claims 1 to 6; and

a grinding belt.

8. A grinding method using a wheel for a grinding belt, comprising:

a placement process of placing an endless grinding belt on an outer circumferential surface of the wheel for a grinding belt that includes a plurality of arc-shaped hard members forming the outer circumferential surface, and an air tube disposed to the inside in the radial direction of the plurality of hard members;

an inflating process of moving each of the hard members to the outside in the radial direction by inflating the air tube with air, after placing the grinding belt on the outer circumferential surface; and

A grinding process of grinding an object using the grinding belt fixed to the outer circumferential surface in the inflating process.

9. An article that includes an object ground by the grinding methods according to claim 8.