Chuck

Abstract

Provided is a chuck that can prevent entry of dust such as abrasive powder and can also keep grease or the like from being scattered to the outside.　The present invention provides a chuck that comprises a chuck body, a plurality of master jaws, a plurality of clamp jaws, a front cover, and a seal member. Each of a plurality of slide grooves is provided on a front side of the chuck body so as to extend from a center part to an outer circumferential surface in a radial direction that is orthogonal to an axis of rotation. The master jaws are fitted into the slide grooves so as to be capable of sliding therein. The clamp jaws are connected to the master jaws and grip a workpiece. The front cover is installed so as to seal the front side of the chuck body. The seal member seals the outer circumferential surface side of the slide grooves.

Description

zipper

[0001] The present invention relates to a chuck configured to support a workpiece.

[0002] Patent Document 1 discloses a chuck configured to prevent dust particles such as abrasive powder from entering the inside of the chuck body by using a dust cover and a center cover.

[0003] International Publication No. WO2018 / 092879

[0004] In the technology of Patent Document 1, although the front center portion of the chuck body is covered with a dust cover and a center cover, the master jaw slides in a slide groove on the front side of the chuck body, so it is unavoidable that a gap exposed to the outside will be formed between the chuck body and the master jaw. If dust such as abrasive powder (especially fine chips) or cutting water enters the interior through this gap, it may cause malfunction of the master jaw, etc.

[0005] In addition, because the area where grease, etc., is applied to ensure smooth sliding of the master jaw is exposed to the outside, the grease, etc. inside the chuck body can be scattered by the centrifugal force caused by the rotation of the chuck. A lack of grease in the sliding area of ​​the master jaw adversely affects the operation of the master jaw, so maintenance work such as periodic replenishment of grease, etc. is required.

[0006] The present invention has been made in view of the above circumstances, and provides a chuck that can prevent dust such as abrasive powder from entering the inside and can prevent grease and the like from scattering to the outside.

[0007] According to the present invention, the following inventions are provided: [1] A chuck comprising a chuck body, a plurality of master jaws, a plurality of clamp jaws, a front cover, and a seal member, wherein the chuck body has a plurality of slide grooves, each of which is provided on a front side of the chuck body so as to extend from a center to an outer circumferential surface along a radial direction perpendicular to a rotation axis, the master jaw is configured to be slidable within the slide groove when engaged with the slide groove, the clamp jaw is connected to the master jaw and configured to grip the workpiece, the front cover is attached to seal the front side of the chuck body, and the seal member is configured to seal the outer circumferential surface side of the slide groove. [2] The chuck according to [1], wherein the chuck body comprises a body and an outer circumferential surface cover, the outer circumferential surface cover forms a part of the outer circumferential surface of the chuck body and has an insertion hole configured so that the master jaw is slidably inserted therethrough, and the seal member is disposed in the insertion hole. [3] The chuck according to [1] or [2], wherein the master jaw has a sliding portion having a cross-sectional shape that matches the shape of the slide groove and an outer end portion connected to the radially outer side of the sliding portion, and the cross-sectional shape of the outer end portion is configured to be different from the cross-sectional shape of the sliding portion. [4] The chuck according to any one of [1] to [3], wherein the seal member includes a dust seal arranged on the radially outer side and an X-ring arranged on the radially inner side. [5] The chuck according to any one of [1] to [4], wherein the master jaw has an engaging portion at an inner end portion in the radial direction, the engaging portion being configured to slidably engage with an engaged portion of a wedge plunger, and a solid lubricating coating is provided on a sliding area between the engaging portion and the engaged portion.

[0008] In the chuck of the present invention, the front side of the slide groove in which the master jaw slides is sealed by the front cover, and the radial outer side of the slide groove is sealed by the seal member. Therefore, no gap exposed to the outside occurs between the chuck body and the master jaw. As a result, dust such as abrasive powder is prevented from entering the inside, and grease and the like are also prevented from scattering to the outside.

[0009] Fig. 1A is a perspective view of the chuck 1, and Fig. 1B is a front view of the chuck 1. An exploded perspective view showing a schematic configuration of the chuck 1. Fig. 3A is a perspective view of the body 20 of the chuck main body 2, and Fig. 3B is a perspective view of the master jaw 4. Fig. 4A is a perspective view of the outer peripheral surface cover 25, and Fig. 4B is a perspective view of the outer peripheral surface cover 25 seen from a different angle. Fig. 5A is a cross-sectional view taken along line A-A in Fig. 1B, and Fig. 5B is an enlarged view of region A in Fig. 5A.

[0010] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an independent invention.

[0011] <Overall Configuration> FIGS. 1A and 1B show a chuck 1 according to one embodiment of the present invention. The chuck 1 is configured to rotate around a rotation axis while gripping a workpiece to be polished or the like. As shown in FIG. 2, the chuck 1 includes a chuck body 2, a front cover 3, multiple master jaws 4, multiple soft jaws 5, a seal member 6, and a wedge plunger 7. In the figure, arrow Z indicates the rotation axis direction of the chuck 1. Orthogonal to this rotation axis direction is the radial direction (which may also be referred to as the radial direction), as illustrated by arrow X. Along the rotation axis direction, the upper side of the page corresponds to the front side facing the workpiece, and the lower side corresponds to the back side. In this embodiment, the body 20 of the chuck body 2 has a disk-like shape that is nearly circular when viewed from the front. More precisely, the body 20 has a circular ring shape in a plan view, with a central portion 24 having a circular hole. However, the shape of the body 20 is not limited to this configuration; for example, a configuration in which the outer edge is polygonal when viewed from the front can also be adopted.

[0012] The chuck body 2 is made of a metal material or the like and has a body 20, a front surface 21, an outer peripheral surface 22, a plurality of slide grooves 23, and an outer peripheral surface cover 25. The front surface 21 is a surface facing a workpiece gripped by the chuck 1. The outer peripheral surface 22 is configured to be continuous with the front surface 21. In this embodiment, the outer peripheral surface 22 is configured to be perpendicular to the front surface 21. However, the outer peripheral surface 22 and the front surface 21 do not necessarily have to be disposed at a right angle. Furthermore, where the outer peripheral surface cover 25 is provided on the body 20, the outer peripheral surface cover 25 forms part of the outer peripheral surface of the chuck body 2. Here, the body 20 and the outer peripheral surface cover 25 are configured as separate parts, but the chuck body 2 may be configured by integrating the body 20 and the outer peripheral surface cover 25.

[0013] 3A , the plurality of slide grooves 23 are provided on the front surface 21 side of the chuck body 2 along a radial direction perpendicular to the rotation axis. Each slide groove 23 is provided to extend radially from the central portion 24 of the chuck body 2 to the outer peripheral surface 22. In this embodiment, three slide grooves 23 are provided. However, the number of slide grooves 23 is not limited to three, as long as it is at least two or more. The chuck body 2 is fixed to the machine tool by, for example, a plurality of mounting bolts or the like.

[0014] <Master jaw 4> The master jaw 4 is configured to be slidable within the slide groove 23 while engaged with the slide groove 23. As shown in Fig. 3B , the master jaw 4 is configured, in order from the inside in the radial direction, to have an engaging portion 41, a sliding portion 42, and an outer end portion 43. The engaging portion 41 is provided at the inside end in the radial direction and is configured to slidably engage with the engaged portion 71 of the wedge plunger 7.

[0015] The sliding portion 42 is configured so that its cross-sectional shape matches the shape of the slide groove 23. More specifically, when viewed from the radial direction, the cross-sectional shapes of the sliding portion 42 and the slide groove 23 match. Here, both the sliding portion 42 and the slide groove 23 have an inverted T-shaped cross-sectional shape. Therefore, the sliding portion 42 fits snugly into the slide groove 23 and can slide smoothly within the slide groove 23 without rattle.

[0016] The outer end 43 is disposed at the radially outermost position of the master jaw 4. The outer end 43 is configured to protrude from the outer peripheral surface 22 of the chuck body 2 (here, the outer main surface of the outer peripheral surface cover 25). The cross-sectional shape of the outer end 43 is configured to differ from the cross-sectional shape of the sliding portion 42. In this embodiment, the outer end 43 is cylindrical and has a circular cross section. As described above, the inverted T-shaped cross section of the sliding portion 42 can suppress rotation and lifting of the master jaw 4 even if a strong force is applied to the master jaw 4 during machining of a workpiece. On the other hand, the circular cross-sectional shape of the outer end 43 makes it easier to abut the seal member 6 against the outer peripheral surface of the outer end 43, thereby improving sealing performance. If the entire cross-sectional shape of the master jaw 4 were circular, it would be difficult to suppress lifting and rotation of the master jaw 4. However, since the circular cross section is limited to the outer end 43 here, such a problem does not occur.

[0017] However, the cross-sectional shape of the outer end 43 is not limited to a circle. For example, a polygon with hexagons or more sides can easily contact the seal member 6, just as in the case of a circle. It is also possible to adopt an ellipse or a shape that combines arcs and straight lines. Although the master jaw 4 has an original configuration, existing configurations can be used for parts other than the outer end 43, which allows for efficient production of the master jaw 4.

[0018] <Soft Jaws 5> As shown in FIG. 2 , the soft jaws 5 are connected to the outer end 43 of the master jaw 4. Here, they are detachably attached to the radially outer end surface of the outer end 43 with fasteners such as screws. The soft jaws 5 have a connecting portion 5a and a gripping portion 5b. The connecting portion 5a is connected to the master jaw 4. The gripping portion 5b has a flat support surface on the radially inner side that supports the workpiece and is configured to grip the workpiece. As each master jaw 4 moves radially inward, the workpiece is sandwiched and gripped by the three gripping portions 5b. In this embodiment, the soft jaws 5 correspond to the clamp jaws of the present invention. The soft jaws 5 are made of ferrous material that has not been hardened by heat treatment such as quenching. However, ferrous material or other metals that have been hardened by heat treatment can also be used as the clamp jaws. Although three master jaws 4 and three soft jaws 5 are provided, as with the slide grooves 23 described above, the number of the soft jaws 5 is not limited to three, as long as there are at least two or more.

[0019] The soft jaws 5 can be of various shapes depending on the application. Here, the soft jaws 5 are configured to grip a disk-shaped workpiece that is approximately the same size as the front surface 21 of the chuck body 2. For example, if the diameter of the workpiece to be gripped is small, it is advisable to use soft jaws 5 that have a portion that extends radially inward above the chuck body 2. By appropriately selecting and using soft jaws 5 of an appropriate shape, it is possible to accommodate workpieces of various sizes and shapes, and it is also possible to grip the workpiece from either the outside or the inside.

[0020] <Front cover 3> The front cover 3 is configured to seal the front surface 21 side of the chuck body 2. Here, the front cover 3 is detachably attached to the front surface 21 with fasteners such as screws. An O-ring 31 is disposed between the front cover 3 and the front surface 21. When the front cover 3 is attached to the front surface 21 of the chuck body 2, the front surface 21 side of the slide groove 23 and the central portion 24 is sealed, so that dust does not enter the interior of the front surface 21 of the chuck body 2 and grease does not scatter to the outside. The slide groove 23 is open to the outer peripheral surface 22 side, but the outer peripheral surface 22 side of the slide groove 23 is sealed by the outer peripheral surface cover 25 and the seal member 6, as described below.

[0021] <Outer peripheral surface cover 25 and sealing member 6> The outer peripheral surface cover 25 is disposed on the outer peripheral surface 22 of the chuck body 2. A flat portion 22a for attaching the outer peripheral surface cover 25 is formed on the outer peripheral surface 22. The outer peripheral surface cover 25 is fixed by a fastener such as a screw in a state where it is in close contact with the flat portion 22a via a packing 22b.

[0022] 4A and 4B , the outer peripheral cover 25 has an insertion hole 25a through which the outer end 43 of the master jaw 4 is slidably inserted. In this embodiment, the insertion hole 25a is circular so that the cylindrical outer end 43 can slide smoothly. The shape of the insertion hole 25a is preferably configured to match the cross-sectional shape of the outer end 43. For example, if the cross-sectional shape of the outer end 43 is polygonal, the shape of the insertion hole 25a will also be polygonal. In this embodiment, circular shapes are used for the cross-sectional shape of the outer end 43 and the shape of the insertion hole 25a to maximize sealing performance.

[0023] A seal member 6 is disposed on the inner circumferential surface of the insertion hole 25a. The seal member 6 includes a dust seal 6a disposed radially outward and an X-ring 6b disposed radially inward. As shown in FIGS. 5A and 5B , the dust seal 6a and the X-ring 6b are configured to seal the radially outer side of the slide groove 23 by abutting against the outer circumferential surface of the outer end 43. By disposing the dust seal 6a on the outer side, dust and other particles adhering to the outer circumferential surface of the outer end 43 can be prevented from entering the slide groove 23. Furthermore, by disposing the X-ring 6b on the inner side, grease leakage radially outward from the slide groove 23 can be prevented. The X-ring 6b has an X-shaped cross section, and its four tips reliably capture grease. As a result, in the sliding area between the insertion hole 25a of the outer circumferential surface cover 25 and the outer end 43 of the master jaw 4, dust and other particles are prevented from entering the interior and grease and other particles are prevented from scattering to the exterior. Furthermore, not only when a workpiece is being machined, but also when no workpiece is being machined, dust particles such as chips accumulated during machining can be prevented from entering the inside of the chuck body 2.

[0024] <Solid Lubricant Coating Treatment> Furthermore, the chuck 1 is provided with a solid lubricant coating by being subjected to a solid lubricant coating treatment. This solid lubricant coating is provided mainly in the sliding area between the engaging portion 41 of the master jaw 4 and the engaged portion 71 of the wedge plunger 7. As shown in FIG. 2 , the engaging portion 41 of the master jaw 4 is configured as a T-shaped tapered protrusion, and the engaged portion 71 of the wedge plunger 7 is configured as a T-shaped tapered groove. The engaging portion 41 and the engaged portion 71 fit snugly together and slidably engage with each other. Grease is applied to the sliding area between the engaging portion 41 and the engaged portion 71, and the solid lubricant coating treatment is also performed.

[0025] The solid lubricant coating process is a process in which fine particles, either singly or in combination, are dispersed in paint and coated on the surface of the sliding region. Examples of solid lubricant coating processes include Parlube coating. Furthermore, examples of fine particles include materials with excellent lubricity, such as fluorine, graphite, and molybdenum disulfide. Because of the solid lubricant coating, even if grease in the sliding region between the engaging portion 41 and the engaged portion 71 flows outward due to centrifugal force caused by the rotation of the chuck 1, the lubricity of the sliding region between the engaging portion 41 and the engaged portion 71 is maintained. This reduces the frequency of maintenance work such as grease replenishment. Furthermore, the above-described seal member 6 prevents grease and other lubricants from scattering outside the chuck body 2. This allows the chuck 1 to be used suitably in environments requiring relatively high cleanliness, such as when polishing semiconductor components as workpieces.

[0026] <Operation of Chuck 1> The above-described wedge plunger 7 is housed in the central portion 24 of the chuck body 2 with the engaging portion 41 of the master jaw 4 engaged with the engaged portion 71. A draw pipe (not shown) is connected to the rear end of the wedge plunger 7, and the master jaw 4 reciprocates radially when this draw pipe is reciprocated by a fluid pressure rotary cylinder or the like. In other words, the reciprocating movement of the wedge plunger 7 in the rotation axis direction becomes the reciprocating movement of the master jaw 4 in the radial direction. This reciprocating movement causes the soft jaws 5 attached to the master jaw 4 to grip or release the grip of the workpiece.

[0027] The chuck 1 rotates at high speed by a rotational driving force transmitted from a fluid pressure rotary cylinder or the like, but the master jaw 4 and wedge plunger 7 are sealed by the front cover 3, outer peripheral surface cover 25, seal member 6, etc., which prevents grease and the like from scattering from inside the chuck 1. Also, abrasive powder and the like generated during machining of the workpiece are prevented from entering the inside of the chuck 1. Moreover, the dust seal 6a can prevent dust and the like from being drawn into the inside when the master jaw 4 moves radially inward after the chuck 1 has stopped.

[0028] <Other Embodiments> In the above embodiment, an example in which the chuck 1 is positioned horizontally to grip the workpiece has been described. However, the chuck 1 can also be positioned vertically or tilted at other angles. While an example in which the soft jaws 5 are connected to the outer end 43 of the master jaw 4 has been described, if the master jaws 4 are designed to protrude significantly from the outer peripheral surface 22, the attachment position of the soft jaws 5 can be positioned inward of the outer end 43. In this case, the soft jaws 5 do not need to be attached to the radially outer end surface of the master jaw 4, and the soft jaws 5 can be attached to a surface other than the outer end surface of the master jaw 4. If the connection portion 5a of the soft jaws 5 has a portion extending radially inward, the master jaws 4 do not necessarily need to protrude outside the outer peripheral surface 22. In this case, the seal member 6 may be abutted against the outer peripheral surface of the connection portion 5a of the soft jaws 5. When a configuration in which the outer peripheral surface cover 25 is attached to the body 20 is adopted, both the slide groove 23 and the insertion hole 25a, along which the outer peripheral surface of the master jaw 4 slides, may be interpreted as corresponding to the slide groove of the present invention.

[0029] 1: chuck, 2: chuck body, 3: front cover, 4: master jaw, 5: soft jaw, 6: seal member, 6a: dust seal, 6b: X-ring, 7: wedge plunger

Claims

1. A chuck comprising a chuck body, a plurality of master jaws, a plurality of clamp jaws, a front cover, and a seal member, wherein the chuck body has a plurality of slide grooves, each of which is provided on the front side of the chuck body, extending from the center to the outer periphery along a radial direction perpendicular to the rotation axis, the master jaw is configured to be able to slide freely within the slide groove when engaged with the slide groove, the clamp jaw is connected to the master jaw, and is configured to grip the workpiece, the front cover is attached to seal the front side of the chuck body, and the seal member is configured to seal the outer periphery side of the slide groove.

2. A chuck as claimed in claim 1, wherein the chuck body comprises a body and an outer peripheral surface cover, the outer peripheral surface cover forms part of the outer peripheral surface of the chuck body and has an insertion hole configured to allow the master jaw to be slidably inserted therethrough, and the seal member is disposed in the insertion hole.

3. A chuck as claimed in claim 2, wherein the master jaw has a sliding portion having a cross-sectional shape that matches the shape of the slide groove, and an outer end portion connected to the radially outer side of the sliding portion, and the cross-sectional shape of the outer end portion is configured to be different from the cross-sectional shape of the sliding portion.

4. A chuck according to any one of claims 1 to 3, wherein the sealing member includes a dust seal arranged on the radially outer side and an X-ring arranged on the radially inner side.

5. A chuck as claimed in claim 4, comprising an engaging portion at the radially inner end of the master jaw, the engaging portion configured to slidably engage with an engaged portion of a wedge plunger, and a solid lubricating coating provided in the sliding area between the engaging portion and the engaged portion.