Gripping device in a work grinding apparatus

Abstract

The gripping device that constitutes the work grinding device is structured to be able to securely and stably grip a work having an end face with an irregular three-dimensional shape. 【Solution means】Among a pair of clamp parts 4 and 5 that constitute the gripping device 3, one of the clamp parts 4(5) is provided with a plurality of gripping materials 41 that are independent of each other as follower clamp parts. The plurality of gripping materials 41 are housed in the follower clamp part 4(5) so as to be able to protrude and retract independently from the end face of the follower clamp part 4(5). When the work 12 is gripped in the axial direction between the end face of the other clamp part 5(4), the axial tip faces of all the gripping materials 41 grip the work 12 together with the end face of the other clamp part 5(4).

Description

Technical Field

[0001] The present invention relates to a gripping device in a workpiece grinding apparatus that enables grinding of the peripheral surface while stably gripping a workpiece whose end surface on one axial side is not a flat surface.

Background Art

[0002] When grinding or polishing the peripheral surface of a workpiece such as an ingot whose surface is finished to a cylindrical shape, when a pair of clamp parts grip the workpiece in the axial direction, the axis of the workpiece may not coincide with the axis of the clamp parts. In preparation for such a case, when the pair of clamp parts grip the workpiece, a structure may be provided that enables angle adjustment with respect to the workpiece so that the axes of the workpiece and the clamp parts can be aligned (see Patent Documents 1 to 3).

[0003] In principle, it is assumed that the workpiece is formed into a cylindrical shape having flat surfaces on both end faces in the axial direction that are orthogonal to the axis (paragraph 0032 of Patent Document 3). However, since the end face of the workpiece may be inclined with respect to the axis (paragraph 0015 of Patent Document 1), the angle adjustment of the pair of clamp parts with respect to the workpiece also corresponds to the irregular shape of the workpiece itself.

[0004] However, supporting each clamp part so as to be angle-adjustable with respect to the axis of the spindle that supports each clamp part itself may cause the clamp part to displace with respect to the spindle when processing the workpiece such as grinding while the pair of clamp parts grip the workpiece. In that case, since the stability of the workpiece in the supported state is likely to be impaired, the accuracy of grinding or the like may be reduced.

[0005] It may be considered that the stability of the clamp part in the state of gripping the workpiece can be ensured by increasing the pressure between the pair of clamp parts that grip the workpiece. However, since there is also a possibility of applying an excessive axial compressive force to the workpiece, there is a possibility of generating minute distortion in a direction orthogonal to the axial direction in the workpiece during grinding. If distortion occurs in the workpiece during grinding, it also affects the grinding accuracy.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] On the other hand, when the work is a silicon carbide single crystal (SiC) ingot, due to its manufacturing method (sublimation method), although one end face on the axial direction side is a flat surface, unevenness may occur on the other end face. Therefore, when the work is a SiC ingot, it is required to be able to securely grip the end face of the ingot with such unevenness.

[0008] Specifically, the shape of the uneven end face of this type of ingot is neither simply a plane inclined with respect to the axis of the work nor a conical shape, but an irregular three-dimensional shape. Therefore, the clamp part that grips the end face on that side is required to be able to follow the irregular three-dimensional shape and press the end face in the axial direction to hold (grip) the work. "Irregular three-dimensional shape" means having different shapes for each individually manufactured ingot.

[0009] Based on the above background, the present invention proposes a gripping device in a work grinding apparatus having a structure capable of securely gripping a work having an end face with an irregular three-dimensional shape and stably gripping the work without applying excessive axial compressive force to the work.

Means for Solving the Problems

[0010] In the gripping device in the work grinding apparatus according to claim 3, a pair of clamp parts are opposed to each other in the longitudinal direction of the support base, grip the work when approaching each other, and are supported by a support part so as to be rotatable about an axis together with the work in a state where the work is gripped. A rotation driving device that rotates the pair of clamp parts that have gripped the work together with the support part about the axis of the clamp part. It includes a linear driving device that linearly moves at least one of the pair of clamp parts in the longitudinal direction with respect to the support base together with the support part that supports the one. Among the pair of clamp parts, either one of the clamp parts or the other clamp part has a plurality of gripping members independent of each other as follower clamp parts. The plurality of gripping members are retractably housed in the follower clamp part from an end face of the follower clamp part, and when gripping the work in the axial direction between an end face of the other clamp part or the one clamp part, axial front end faces of all the gripping members grip the work together with the end face of the other clamp part or the one clamp part. A detection material that contacts an end face of the work when the follower clamp part moves toward the work side of the follower clamp part and transmits a signal of the contact to the linear driving device is installed on the end face of the follower clamp part on the work side. In a state where all the gripping members are immersed in the follower clamp part, a constituent requirement is that a front end face of the detection material on the work side is located on the work side with respect to front end faces of all the gripping members on the work side.

[0011] The "pair of clamp parts that face each other in the longitudinal direction of the support table, grip the workpiece when approaching each other, and are supported by the support parts" means that, as shown in FIGS. 1 to 3, in the longitudinal direction of the support table 2 that supports the workpiece grinding apparatus 1, a pair of clamp parts 4 and 5 that grip (clamp) the workpiece 12 in its axial direction are arranged to face each other, and each clamp part 4 and 5 is supported (held) by the support parts 6 and 7 respectively. The "longitudinal direction of the support table 2" refers to the length direction (long side direction) when the support table 2 is viewed in a plane or an elevation. The "axial direction of the workpiece 12" refers to the axial center direction of the workpiece 12.

[0012] The "pair of clamp parts that are supported by the support parts so as to be rotatable about the axis together with the workpiece in a state of gripping the workpiece" means that when the pair of clamp parts 4 and 5 are in a state of gripping the workpiece 12, the pair of clamp parts 4 and 5 and the workpiece 12 are rotatable about the axis together with the support parts 6 and 7. The "axis" refers to the axis of the clamp parts 4 and 5 and the support parts 6 and 7, and is also the axis of the workpiece 12. The pair of clamp parts 4 and 5 constitute the gripping device 3.

[0013] The "rotary drive device that rotates the pair of each clamp part that grips the workpiece together with the support part about the axis of the clamp part" means that the rotary drive device rotates the pair of each clamp part 4 and 5 that grip the workpiece 12 and the support parts 6 and 7 that support the clamp parts 4 and 5 about the axis of the clamp part 4 and 5. The rotary drive device is a motor or the like. The rotary drive device interlocks and rotates the one clamp part 4 (5) and the other clamp part 5 (4) simultaneously with the support parts 6 and 7 that support them respectively.

[0014] The "linear drive device that linearly moves at least one of each pair of clamping parts together with the support part that supports the one in the longitudinal direction with respect to the support base" means the following. That is, among the pair of clamping parts 4 and 5, a linear drive device 8 that reciprocates (linearly moves) one of the clamping parts 4(5) and the support part 6(7) that supports it in the longitudinal direction of the support base 2 is connected only to one of the clamping parts 4(5) (support part 6(7)), or may be connected to each of both clamping parts 4 and 5 (support parts 6 and 7). The linear drive device 8 is directly or indirectly connected to the clamping part 4(5) or the support part 6(7).

[0015] When the pair of clamping parts 4 and 5 grip the workpiece 12, basically, it is sufficient to reciprocate one of the clamping parts 4(5) (support part 6(7)). If both clamping parts 4 and 5 (support parts 6 and 7) can reciprocate, the working efficiency when gripping the workpiece 12 can be improved, or fine adjustment becomes possible.

[0016] "Among the pair of clamping parts, either one of the clamping parts or the other clamping part serves as a follower clamping part" means that among the pair of clamping parts 4 and 5, either one of the clamping parts 4(5) or the other clamping part 5(4) functions (behaves) as a follower clamping part. "Having a plurality of gripping members independent of each other as a follower clamping part" means that a plurality or a plurality of gripping members 41 are stored in a state independent of each other in any of the clamping parts 4(5) that serve as the follower clamping part.

[0017] "The plurality of gripping members are stored in the follower clamping part so as to be able to protrude and retract from the end face of the follower clamping part" means that each of the plurality (a plurality of) gripping members 41 is stored in the follower clamping part 4(5) so as to be able to protrude and retract independently of the other gripping members 41. The gripping member 41 is stored in the follower clamping part 4(5) so as to be able to protrude and retract in the axial direction of the follower clamping part 4(5) from its end face. The "axial direction of the follower clamping part 4(5)" refers to the linear movement direction of the follower clamping part 4(5) and is also the axial center direction of the follower clamping part 4(5).

[0018] Whether the follower clamp part is the one clamp part 4(5) or the other clamp part 5(4), the gripping material 41 can protrude and retract freely from the end face on the workpiece 12 side of the follower clamp part 4(5).

[0019] The follower clamp part 4(5) grips the end face of the workpiece 12 having an irregular three-dimensional shape with a plurality of gripping materials 41 together with the other or one of the clamp parts 5(4). As shown in FIG. 7, the plurality of gripping materials 41 are basically evenly distributed in the circumferential direction at positions equidistant from the center of the end face of the follower clamp part 4(5) in the radial direction. The "radial direction" refers to the radial direction when the end face of the clamp part 4(5) is circular.

[0020] When the plurality of gripping materials 41 are evenly distributed in the circumferential direction at positions equidistant from the center of the end face of the follower clamp part 4(5) in the radial direction, when the plurality of gripping materials 41 grip the workpiece 12, although they are dispersed at a plurality of locations on the end face of the workpiece 12, an axially uniform compressive force can be applied. Therefore, the workpiece 12 can be gripped while being stabilized.

[0021] The plurality of gripping materials 41 share the compressive force required to grip the workpiece 12 together with the clamp part 5(4) on the side opposite to the follower clamp part 4(5). In other words, the plurality of gripping materials 41 disperse and bear the reaction force of the compressive force applied to the workpiece 12 when gripping the workpiece 12, so that the reaction force acting on the follower clamp part 4(5) is dispersed in the circumferential direction.

[0022] When the holding member 41 is rod-shaped as shown in Fig. 6, at least three such holding members are sufficient for stably holding the workpiece 12. For example, when the holding member 41 is plate-shaped with a width in the circumferential direction of the clamp portion 4(5), or is a curved plate shape or the like, two (two sheets) may be sufficient at positions sandwiching the center of the end face of the clamp portion 4(5). The "curved plate shape or the like" means that the outer peripheral side in the radial direction is convexly curved or bent from the center of the end face of the clamp portion 4(5). However, the ability of the follower clamp portion 4(5) to follow the end face of the workpiece 12 having an irregular three-dimensional shape is higher when the holding member 41 is rod-shaped and the number is larger.

[0023] Since each holding member 41 can independently protrude from and retract into the follower clamp portion 4(5), according to the shape of the end face of the workpiece 12 having an irregular three-dimensional shape, when each holding member 41 protrudes, it can press the end face of the workpiece 12 in the axial direction at its respective storage position, enabling the workpiece 12 to be held.

[0024] Particularly, when the end of the holding member 41 on the workpiece 12 side has a shape in which the cross-sectional area perpendicular to the axis of the holding member 41 decreases from the support portion 6(7) side toward the workpiece 12 side as shown in Fig. 6 (Claim 5), each holding member 41 can follow the delicate irregular shape of the end face of the workpiece 12 while receiving a hydraulic pressure such as the hydraulic pressure required for holding the workpiece 12 from the back surface (support portion 6 side). The "support portion 6(7)" refers to the support portion that supports the follower clamp portion 4(5) that houses the holding member 41.

[0025] For example, when the entire length of the holding member 41 is a bar with a uniform cross-sectional shape, one (one piece) of the holding member 41 needs to have a cross-sectional area (thickness) for receiving the hydraulic pressure required for holding the workpiece 12 from the axial back surface. If the tip end face on the workpiece 12 side also has an area equal to that cross-sectional area, since it contacts the workpiece 12 with a surface having a certain area, it is difficult to follow the delicate irregular shape such as unevenness on the end face of the workpiece 12. In this case, the holding member 41 tries to move to a portion where the workpiece 12 can be stably held, and there is a possibility that the workpiece 12 may deviate from the optimal holding position by the holding member 41. The "axial direction of the holding member 41" refers to the axial direction of the axis of the holding member 41, and is also the axial direction of the axis of the follower clamp portion 4(5).

[0026] On the other hand, since the area of the tip surface of the gripping member 41 on the side of the workpiece 12 is smaller than the area on the side receiving the hydraulic pressure, in comparison with the case of a uniform cross-sectional shape along the entire length, the contact state with the workpiece 12 becomes closer to point contact than surface contact. Therefore, it can correspond to the fine uneven shape of the end surface of the workpiece 12 and is easier to follow. As a result, it becomes easier to stably hold the workpiece 12 without shifting it with respect to the pair of clamp portions 4 and 5.

[0027] The fact that each gripping member 41 can independently project and retract from the follow clamp portion 4(5) is made possible, for example, as shown in FIG. 6, by supplying a pressure fluid such as pressure oil from the rear side in the axial direction of the gripping member 41 into a plurality of storage portions 42 that store each gripping member 41 in the follow clamp portion 4(5), and by applying an equal hydraulic pressure to the rear surface in the axial direction of each gripping member 41. The "rear surface in the axial direction of the gripping member" refers to the surface on the side opposite to the tip surface of the gripping member 41 on the side of the workpiece 12. The cross-sectional areas orthogonal to the axes of all the storage portions 42 are equal, and the cross-sectional areas orthogonal to the axes of all the gripping members 41 are equal.

[0028] In this case, by applying an equal hydraulic pressure to the rear surface in the axial direction of each gripping member 41, regardless of the end surface shape of the workpiece 12, each gripping member 41 can press the workpiece 12 toward the other or one of the clamp portions 5(4) with equal pressure. When pressing the workpiece 12 by all the gripping members 41, there is no difference in the pressure for holding the workpiece 12 for each of the plurality of gripping members 41. Therefore, an unbalanced pressure does not act on the end surface of the workpiece 12, and an eccentric load is not applied to the workpiece 12.

[0029] As described above, in accordance with the shape of the end surface of the workpiece 12 having an irregular three-dimensional shape, each gripping member 41 in the follow clamp portion 4(5) presses the end surface of the workpiece 12 in the axial direction at each storage position. As a result, since all the gripping members 41 press the end surface of the workpiece 12 having an irregular three-dimensional shape in the axial direction together with the other clamp portion 5(4) or one of the clamp portions 4(5), it becomes possible to reliably grip the workpiece 12.

[0030] In addition, since each gripping member 41 presses the workpiece 12 toward the other or one of the clamp portions 5(4) with an equal pressure, it is possible to stably grip the workpiece 12 without applying an excessive axial compressive force to the workpiece 12.

[0031] When the following clamp portion 4 moves toward the workpiece 12 by the linear drive device 8, a detection member 43 for issuing a command to stop the following clamp portion 4 due to contact with the workpiece 12 to the motor 81 of the linear drive device 8 may be installed (fixed) on the end face on the workpiece 12 side of the following clamp portion 4 as shown in FIG. 6. In this case, when the following clamp portion 4 moves toward the workpiece 12, regardless of the end face shape of the workpiece 12 on the side of the following clamp portion 4, it is desirable that the detection member 43 always comes into contact with the end face of the workpiece 12 before any of the gripping members 41.

[0032] From this point, as shown in FIG. 6, when all the gripping members 41 are in a state of being immersed in the following clamp portion 4, it is appropriate that the tip end face on the workpiece 12 side of the detection member 43 is located closer to the workpiece 12 side than the tip end face on the workpiece 12 side of all the gripping members 41 (Claim 3). In other words, in detecting that the detection member 43 has contacted the workpiece 12, it is appropriate that none of the gripping members 41 contact the workpiece 12 before the detection member 43 contacts.

[0033] This is because if any of the gripping members 41 contacts the workpiece 12 before the detection member 43, an error may occur in the optimal detection timing by the detection member 43. However, if each gripping member 41 is in a state where the hydraulic pressure received on the back surface is released and is freely movable in the axial direction within the storage portion 42, the influence on the detection member 43 due to the contact of the gripping member 41 is small. In FIG. 6, the lower gripping member 41 shows an immersed state. A two-dot chain line indicating that the upper gripping member 41 is moving toward the storage portion 42 side shows the immersed state.

[0034] That the detection member 43 has contacted the workpiece 12 is detected by a sensor 94 installed behind the support portion 6 that supports the following clamp portion 4, and the signal (information) is transmitted to the motor 81 of the linear drive device 8, and the movement of the following clamp portion 4 (support portion 6) by the linear drive device 8 toward the workpiece 12 side stops.

[0035] When the detection material 43 is in a state of being immersed in the following clamp portion 4 of the full gripping member 41, the tip surface of the detection material 43 on the workpiece 12 side is located closer to the workpiece 12 than the tip surface of the full gripping member 41. Thus, especially when the workpiece 12 is a SiC ingot having a three-dimensional shape with a convex or uneven end surface shape on the side of the following clamp portion 4 as a whole, regardless of the end surface shape of the workpiece 12, it is possible to obtain a state in which the detection material 43 contacts the end surface of the workpiece 12 prior to any of the gripping members 41 (full gripping member 41).

[0036] Especially when the workpiece 12 is a SiC ingot, since the irregular three-dimensional shape often has a convex shape at the center or near the center of the end surface of the workpiece 12, or a convex shape at the periphery, it is reasonable to arrange the detection material 43 at the center of the end surface of the following clamp portion 4 on the workpiece 12 side as shown in FIGS. 6 and 7.

[0037] Also, when the full gripping member 41 of the following clamp portion 4 grips the workpiece 12, it is necessary that the detection material 43 is not involved in the gripping of the workpiece 12, that is, the detection material 43 does not inhibit the gripping of the workpiece 12 by the full gripping member 41. For this purpose, when the full gripping member 41 protrudes, it is appropriate that the tip surface of the full gripping member 41 on the workpiece 12 side is located closer to the workpiece 12 than the tip surface of the detection material 43 on the workpiece 12 side (Claim 4).

[0038] When the full gripping member 41 protrudes, the tip surface of the full gripping member 41 on the workpiece 12 side is located closer to the workpiece 12 than the tip surface of the detection material 43. Thus, when the following clamp portion 4 moves toward the workpiece 12 side, any part of the tip surface of the full gripping member 41 will surely contact the end surface of the workpiece 12, and it becomes possible to grip the workpiece 12 together with the fixed clamp portion 5.

[0039] The phrase "when the plurality of gripping members grip the workpiece in the axial direction between the other clamp part or the end face of one clamp part, the axial end faces of all the gripping members grip the workpiece together with the other clamp part or the end face of one clamp part" in claim 3 means the following. That is, when all the gripping members 41 in the follower clamp part 4 grip the workpiece 12 in the axial direction between the other clamp part or the end face of one clamp part 5(4), it means that all the gripping members 41 and the other clamp part or the end face of one clamp part 5(4) sandwich and grip the workpiece 12 in the axial direction. The "axial end face of the gripping member" refers to the end face on the side of the other clamp part 5(4) or the like that pairs with the gripping member 41.

[0040] The shape of the end face on the workpiece 12 side of the clamp part 5 on the side opposite to the follower clamp part 4 is not particularly limited. Depending on the type (material) of the workpiece 12 and the like, it may have a plane inclined with respect to the axis of the workpiece 12 or may have a non-planar shape. However, in the case of the SiC ingot described above, one end face of the workpiece 12 has an irregular three-dimensional shape, while the other end face is a flat surface perpendicular to the axis. Therefore, for the SiC ingot workpiece 12, it is appropriate for the end face on the workpiece 12 side of the clamp part 5 on the side opposite to the follower clamp part 4 to have a flat surface orthogonal to the axis of the workpiece 12 (claim 6).

[0041] In this case, since the end face on the workpiece 12 side of the clamp part 5 on the side opposite to the follower clamp part 4 is a flat surface orthogonal to the axis of the workpiece 12, the clamp part 5 on the side opposite to the follower clamp part 4 is in surface contact with one end face of the SiC ingot workpiece 12, so it is possible to stably grip the workpiece 12.

[0042] Also, since the end face on the workpiece 12 side of the clamp part 5 opposite to the follower clamp part 4 is a flat surface, when gripping the workpiece 12 with one flat surface between all the gripping members 41 of the follower clamp part 4, it is possible to grip the workpiece 12 without inclining the axis of the workpiece 12 with respect to the axes of the two clamp parts 4 and 5. Therefore, it is possible to accurately polish or grind the peripheral surface of the workpiece 12. [Advantages of the Invention]

[0043] Among a pair of clamp parts for gripping a workpiece, since a plurality of gripping members are stored in one of the clamp parts (the follower clamp part) so as to be able to protrude from and retract into the follower clamp part from the end face on the side of the other clamp part, when gripping the workpiece together with the other clamp part, it is possible to surely grip a workpiece having an irregular three-dimensional end face with the end faces in the axial direction of all the gripping members and the end face of the other clamp part.

[0044] In addition, since the plurality of gripping members can protrude from and retract into the end face of the follower clamp part independently of each other, according to the shape of the end face of a workpiece having an irregular three-dimensional end face, each gripping member presses the end face of the workpiece in the axial direction at its respective storage position, and it is possible to grip the workpiece stably together with the other clamp part.

[0045] In addition, since each gripping member presses the workpiece toward the other or one of the clamp parts with uniform pressure, it is also possible to grip the workpiece without applying an excessive axial compressive force to the workpiece. [Brief Description of the Drawings]

[0046]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiment for Carrying Out the Invention

[0047] FIGS. 1 and 2 show a configuration example of a workpiece grinding apparatus 1 having a pair of clamp portions 4 and 5 that face each other in the longitudinal direction of a support base 2, grip (clamp) a workpiece 12 when approaching each other, and are supported by support portions (spindles) 6 and 7 so as to be rotatable about the axis together with the workpiece 12 in a state where the workpiece 12 is gripped. The pair of clamp portions 4 and 5 constitute a gripping device 3. The support base 2 is a three-dimensional frame-shaped base for supporting the workpiece grinding apparatus 1.

[0048] In addition to the gripping device 3, the workpiece grinding apparatus 1 includes a rotational drive device that rotates each of the pair of clamp portions 4 and 5 that grip the workpiece 12 about the axis of each of them together with the support portions 6 and 7 that support them, and a linear drive device 8 that linearly moves at least one of the clamp portions 4 (5) together with the support portion 6 (7) that supports it in the longitudinal direction with respect to the support base 2. Specifically, the rotational drive device is a workpiece rotation motor 98 and 104 attached to a movable-side pressing unit 9 and a fixed-side pressing unit 10, respectively, which will be described later.

[0049] Of the pair of clamp portions 4 and 5, either one of the clamp portions 4 or the other clamp portion 5 has a plurality of gripping members 41 that can protrude and retract from the end surface on the side of the other clamp portion 5 or one clamp portion 4 side as a follower clamp portion as shown in FIGS. 4 and 6, and are independent of each other and can move in and out toward the workpiece 12 side.

[0050] The drawing shows an example of the case where one of the clamp parts 4, which is part of the movable-side pressing unit 9, behaves as a follower clamp part having a gripping material 41. However, there may also be a case where the other clamp part 5, which is part of the fixed-side pressing unit 10, becomes a follower clamp part having a gripping material 41. Hereinafter, an example of the case where one of the clamp parts 4 is a follower clamp part and the other clamp part 5 is part of the fixed-side pressing unit 10 will be described.

[0051] As shown in FIGS. 1 and 2, the pair of clamp parts 4 and 5 are arranged such that the axes of both are located on the same straight axis on the support base 2, and a linear drive device 8 is indirectly connected to at least one of the clamp parts 4 (5). In the illustrated example, the linear drive device 8 is connected to the movable-side pressing unit 9 integrated with one of the clamp parts 4, which is a follower clamp part. However, the linear drive device 8 may also be connected to the other clamp part 5.

[0052] In the illustrated example, one of the clamp parts (follower clamp part) 4 is integrated with the movable-side pressing unit 9 at the support part 6 that supports it, and since the linear drive device 8 is connected to the movable-side pressing unit 9, the follower clamp part 4 linearly moves in the longitudinal direction of the support base 2 with respect to the fixed-side pressing unit 10 when the linear drive device 8 is driven.

[0053] In the illustrated example, the other clamp part 5 is also integrated with the fixed-side pressing unit 10 at the support part 7 that supports it as will be described later. In this context, since the other clamp part 5 does not linearly move in the longitudinal direction of the support base 2, hereinafter, the clamp part on the side paired with the follower clamp part 4 will be referred to as the fixed clamp part 5. Since the workpiece 12 basically has an outer peripheral surface with a cylindrical shape and the cross-sectional shape is circular, the end faces of both the follower clamp part 4 and the fixed clamp part 5 are basically circular in shape.

[0054] In the drawings, an example is shown in which the linear drive device 8 arranged on the support base 2 is composed of, for example, a motor 81 installed on the support base 2 and a drive shaft 82 and a ball screw 85 for converting the rotational force of the motor 81 into linear motion and transmitting it to the movable-side pressing unit 9. However, as long as the linear drive device 8 is a mechanism that transmits power as the linear motion of the movable-side pressing unit 9 (one of the clamping parts (following clamping part) 4), the mechanism (configuration) and the installation position are not limited, and devices other than the mechanism using a ball screw or the like can also be used.

[0055] In the drawings, as shown in FIGS. 1, 3, and 9, the grinding unit 11 equipped with a grinding wheel 112 shown in FIG. 10 for grinding or polishing the workpiece 12 is installed on the support base 2 adjacent to the support base 2 in the width direction. The fixed-side pressing unit 10 is fixed to the support base 2 so as not to move linearly.

[0056] The grinding unit 11 is installed on the support base 2 so as to be linearly movable in the longitudinal direction of the support base 2, and moves linearly when the motor 114 attached to the grinding unit 11 rotates as shown in FIG. 1. Attached to the grinding unit 11 is a liquid-proof box 111 that houses a cooling nozzle 113 for injecting a coolant for cooling the workpiece 12 during grinding and the like, together with the grinding wheel 112 and the like. As will be described later, the grinding wheel 112 and the like are stored in the liquid-proof box 111.

[0057] Due to the fact that the fixed-side pressing unit 10 is fixed to the support base 2, when the workpiece 12 is gripped by the pair of clamping parts 4 and 5, the movable-side pressing unit 9 equipped with the following clamping part 4 and the support part 6 that supports it moves linearly (approaches) toward the fixed-side pressing unit 10 side when the linear drive device 8 is driven, and the workpiece 12 is gripped by the following clamping part 4 and the fixed clamping part 5.

[0058] In the case of the example shown in FIG. 1, as the motor 81 that constitutes the linear drive device 8 rotates, the drive shaft 82 directly connected to the motor 81 rotates. At the same time, the driven gear 84 meshing with the drive gear 83 connected to the movable side presser unit 9 side of the drive shaft 82 rotates. A ball screw 85 is connected to the driven gear 84 in parallel with the drive shaft 82, and the ball screw 85 rotates as the driven gear 84 rotates. The nut 86 screwed onto the movable side presser unit 9 side of the ball screw 85 reciprocates (linear motion) in the axial direction of the ball screw 85.

[0059] The nut 86 forms a part of the main body 91 that constitutes the movable side presser unit 9, and the main body 91 reciprocates (linear motion) in the axial direction of the ball screw 85 simultaneously with the reciprocation of the nut 86. On one side in the direction orthogonal to the reciprocation direction of the main body 91, a control unit 92 having a control device for controlling the protrusion and retraction of the gripping member 41 that is retractably housed in the follower clamp unit 4 is integrated, and the control unit 92 reciprocates (linear motion) in the axial direction of the ball screw 85 together with the main body 91. The main body 91 of the movable side presser unit 9 runs on the parallel guides 93, 93 laid on the support base 2 in parallel with the axial direction of the ball screw 85, and is guided by both guides 93, 93.

[0060] The support part 6 is integrally connected to the control part 92 of the movable side presser unit 9, and the follower clamp part 4 is integrally connected to the end part of the support part 6 on the fixed clamp part 5 side. The support part 6 is connected to the fixed clamp part 5 side of the control part 92. The support part 6 and the follower clamp part 4 reciprocate when the motor 81 rotates together with the control part 92, and when moving to the fixed clamp part 5 side, they grip the workpiece 12 together with the fixed clamp part 5 supported in a fixed state by the support part 7 which is a part of the fixed side presser unit 10.

[0061] Since the fixed side presser unit 10 equipped with the fixed clamp part 5 is fixed to the support base 2, when gripping the workpiece 12, the movable side presser unit 9 moves toward the fixed side presser unit 10 side, so that the follower clamp part 4 and the fixed clamp part 5 grip the workpiece 12.

[0062] The drawing shows an example of the case where a SiC ingot having an irregular three-dimensional shape on one end face and a flat face perpendicular to the axis on the other end face is used as the workpiece 12 as shown in FIG. 4. The end face of the irregular three-dimensional shape of the workpiece 12 faces the follower clamp portion 4 side, and the end face forming the flat face faces the fixed clamp portion 5 side. In this relationship, the end face of the fixed clamp portion 5 on the side of the follower clamp portion 4 is a flat face orthogonal to the axis of the workpiece 12. The insertion of the workpiece 12 between the follower clamp portion 4 and the fixed clamp portion 5 is operated by a loader unit described later.

[0063] As described above, the follower clamp portion 4 holds a plurality of gripping members 41 that can protrude and retract from the end face on the side of the fixed clamp portion 5. As shown in FIGS. 4 and 6, the plurality of gripping members 41 are housed in a storage portion 42 formed in the follower clamp portion 4 so as to be able to protrude and retract independently of each other from the end face of the follower clamp portion 4. When gripping the workpiece 12, the tip portions of the plurality of gripping members 41 on the side of the workpiece 12 protrude from the end face of the follower clamp portion 4, and when the workpiece 12 is gripped in the axial direction between the tip end faces of the gripping members 41 and the end face of the fixed clamp portion 5, as shown in FIG. 4, the axial tip end faces of all the gripping members 41 grip the workpiece 12 together with the end face of the fixed clamp portion 5.

[0064] The workpiece 12 is inserted between the end faces of both the clamp portions 4 and 5 in a state where a distance is ensured between the opposing end faces while being held by a loader unit (not shown) that carries the workpiece 12 in and out between the pair of clamp portions 4 and 5. However, for the purpose of avoiding the influence on the peripheral surface, which is the grinding surface, due to the workpiece 12 being directly held by the loader unit, a supported material 12A for being directly held by the loader unit is joined to the end face of the workpiece 12 on the side of the fixed clamp portion 5 with an adhesive or the like as shown in FIG. 4.

[0065] In this case, the workpiece 12 is moved toward the fixed clamp portion 5 while being held by the loader unit on the circumferential surface of the supported member 12A integrated therewith until the end surface of the supported member 12A on the fixed clamp portion 5 side comes into surface contact with the end surface of the fixed clamp portion 5. By the end surface of the fixed clamp portion 5 coming into surface contact with the end surface of the supported member 12A, a uniform compressive force is applied in the axial direction of the workpiece 12 in the contact state of the workpiece 12 due to the movement of the follower clamp portion 4 toward the fixed clamp portion 5, and the workpiece 12 is gripped with a constant compressive force.

[0066] When the end surface of the supported member 12A on the fixed clamp portion 5 side comes into contact with the end surface of the fixed clamp portion 5, the end surface of the air supply pipe 102 for cleaning air shown in FIG. 8, which is disposed in the control unit 101 of the fixed-side presser unit 10 to which the support portion 7 supporting the fixed clamp portion 5 is connected, reacts as a sensor dog on the workpiece 12 side. At the same time, the sensor 103 installed behind the control unit 101 (on the side opposite to the fixed clamp portion 5) detects the contact of the workpiece 12 (supported member 12A) with the end surface of the fixed clamp portion 5, whereby the movement of the workpiece 12 by the loader unit toward the fixed clamp portion 5 is stopped. A protrusion 12A1 formed or protruding on the end surface of the supported member 12A on the fixed clamp portion 5 side comes into contact with the end surface of the air supply pipe 102 on the workpiece 12 side.

[0067] The loader unit is disposed on the side of the fixed-side presser unit 10 beside the grinding unit 11 and opposite thereto so as to be reciprocally movable (linearly movable) in the axial direction of the fixed clamp portion 5. The loader unit may be supported by the support base 2. The loader unit moves the workpiece 12 between the follower clamp portion 4 and the fixed clamp portion 5 by linear movement in the longitudinal direction and the width direction of the support base 2 while holding the workpiece 12, and once stops when the flat end surface of the workpiece 12 matches the end surface position of the fixed clamp portion 5. At this time, the axis of the workpiece 12 and the axes of the follower clamp portion 4 and the fixed clamp portion 5 are in a parallel state.

[0068] After the loader unit interposes the workpiece 12 between the follow clamp part 4 and the fixed clamp part 5, it slightly moves the workpiece 12 for fine adjustment toward the fixed clamp part 5 side, and when the workpiece 12 comes into surface contact with the end face of the fixed clamp part 5, it stops the workpiece 12 upon receiving a command from the sensor 103. If there is an obstacle to the gripping of the workpiece 12 by the follow clamp part 4 and the fixed clamp part 5, the loader unit disengages from the stop position of the workpiece 12.

[0069] After the workpiece 12 stops, the movable-side pressing unit 9 moves toward the workpiece 12 side (the fixed-side pressing unit 10 side) by the operation of the linear drive device 8. When a detection material 43 fixed to the end face on the workpiece 12 side of the follow clamp part 4 shown in FIGS. 6 and 7 comes into contact with any part of the end face of the workpiece 12 having an irregular three-dimensional shape, a sensor 94 shown in FIGS. 2 and 5 installed behind the movable-side pressing unit 9 (on the side opposite to the follow clamp part 4) detects the contact of the detection material 43 with the workpiece 12 and stops the movable-side pressing unit 9 (linear drive device 8).

[0070] Here, the fixed position of the detection material 43 on the end face of the follow clamp part 4 is adjusted so that the tip face of the detection material 43 on the end face of the follow clamp part 4, rather than any gripping material 41 protruding from the end face on the workpiece 12 side of the follow clamp part 4, can surely come into contact with the end face of the workpiece 12 when the follow clamp part 4 moves toward the workpiece 12 side.

[0071] Specifically, as shown in FIG. 6, when all the gripping materials 41 are immersed in the storage part 42 of the follow clamp part 4, when viewed in a direction orthogonal to the axial direction of the follow clamp part 4, the tip face on the workpiece 12 side of the detection material 43 is adjusted to be located on the workpiece 12 side relative to the tip face on the workpiece 12 side of all the gripping materials 41. The detection material 43 is fixed to the end face of the follow clamp part 4 at this adjusted position.

[0072] In FIG. 6, it is shown that the tip surface of the uppermost gripping member 41 coincides with the tip surface of the detection member 43. However, in the immersed state, the gripping member 41 is stored in the storage portion 42 as shown by the two-dot chain line. In FIGS. 6 and 7, the detection member 43 is arranged at the center position of the end surface of the follow clamp portion 4. However, it is not always necessary to arrange the detection member 43 at the center of the end surface.

[0073] The end surface on the follow clamp portion 4 side of the work 12 may have an irregular three-dimensional shape as shown in FIG. 4. A plurality of gripping members 41 that are independent of each other are stored in the storage portion 42 of the follow clamp portion 4 so as to be able to protrude and retract in the axial direction of the follow clamp portion 4 while each gripping member 41 follows the irregular arbitrary three-dimensional shape, and all the gripping members 41 come into contact with the end surface of the work 12 and can press the end surface.

[0074] When gripping the work 12, each gripping member 41 protrudes from the end surface on the work 12 side (fixed clamp portion 5 side) of the follow clamp portion 4 toward the work 12 side, and at the position where the end surface on each work 12 side contacts the end surface of the work 12, the protrusion from the follow clamp portion 4 stops by receiving the reaction force from the work 12. In this stopped state, when each gripping member 41 receives the hydraulic pressure described later, a certain compressive force acts on the work 12 from each gripping member 41. The total value of the compressive forces acting on the work 12 from all the gripping members 41 is the reaction force acting on the work 12 from the paired fixed clamp portion 5, and this reaction force becomes the compressive force when the fixed clamp portion 5 grips the work 12.

[0075] In particular, in case the end surface of the work 12 on the follow clamp portion 4 side has a delicate uneven shape, as shown in FIGS. 4 and 6, it is desirable that the end on the work 12 side of the gripping member 41 has a tapered shape from the support portion 6 side toward the work 12 side. Specifically, the end on the work 12 side of the gripping member 41 has a shape in which the cross-sectional area perpendicular to the axis of the gripping member 41 decreases or gradually decreases from the support portion 6 side that supports the follow clamp portion 4 toward the work 12 side.

[0076] Since the tip of the holding member 41 has a tapered shape, as shown in FIG. 4, even when the end face of the workpiece 12 has a fine uneven shape, each holding member 41 can contact the end face of the workpiece 12 substantially at a point or at a surface close to a point. Therefore, it is possible to accurately and stably hold the workpiece 12 without slightly moving (shifting) it in a direction orthogonal to the axis of the workpiece 12.

[0077] Also, when the workpiece 12 is held by all the holding members 41 of the follow clamp portion 4, in order not to involve the detection member 43 in the holding of the workpiece 12, in other words, in order not to inhibit the holding by the holding members 41, when all the holding members 41 protrude, the protruding length of the detection member 43 is adjusted so that the tip end face on the workpiece 12 side of all the holding members 41 is located closer to the workpiece 12 than the detection member 43.

[0078] By the tip end face on the workpiece 12 side of all the holding members 41 during protrusion being located closer to the workpiece 12 than the tip end face on the workpiece 12 side of the detection member 43, it is avoided that any part of the tip end face of the detection member 43 contacts the end face of the workpiece 12 ahead of any part of the tip end face of all the holding members 41. This is possible unless the central portion of the end face on the follow clamp portion 4 side of the workpiece 12 has a three-dimensional shape that is extremely convex toward the follow clamp portion 4 side. When the workpiece 12 is held by all the holding members 41, since the detection member 43 does not contact the workpiece 12 ahead of all the holding members 41, malfunction due to the detection member 43 contacting the workpiece 12 is avoided.

[0079] As shown in FIGS. 5, 6, and 8, a pressure fluid supply pipe 95 for supplying pressure fluid for controlling the protrusion and retraction of each holding member 41 is arranged in the control unit 92 of the movable side presser unit 9. As shown in FIG. 5, pressure fluid such as pressure oil is supplied from a tank 99 to the pressure fluid supply pipe 95 through a control valve 97 such as a solenoid valve by a hydraulic pump 96. The pressure fluid supply pipe 95 branches into each storage portion 42 for storing each holding member 41 in the follow clamp portion 4 as shown in FIG. 6, and equal pressure fluid is supplied into the plurality of storage portions 42 storing each holding member 41, and equal hydraulic pressure such as oil pressure acts on the back surface in the axial direction of each holding member 41.

[0080] In FIG. 6, the two-dot chain line representing the gripping member 41 indicates the protruding position and the retracted position of the gripping member 41, and the difference between the respective positions indicates the possible stroke of the gripping member 41. Basically, all the gripping members 41 are not subjected to the hydraulic pressure by the pressure fluid, and are in a state where they can move freely in the axial direction. They are retracted into the storage portion 42 of the follow clamp portion 4, and the tip surface is kept from protruding beyond the detection member 43. This retracted state is also maintained by utilizing the restoring force, for example, by interposing some spring such as a coil spring around each gripping member 41.

[0081] When the detection member 43 contacts the end surface of the workpiece 12 and the sensor 94 detects this, the pressure fluid is supplied from the tank 99 to each storage portion 42 through the pressure fluid supply pipe 95. Each gripping member 41 protrudes according to the end surface shape of the workpiece 12 and stops when it contacts the end surface of the workpiece 12. Each gripping member 41 receives the pressure necessary for holding from the pressure fluid in the storage portion 42 in the stopped state, and continues to grip the workpiece 12 together with the fixed clamp portion 5 with a constant compressive force. Since the compressive forces acting on the workpiece 12 from the follow clamp portion 4 and the fixed clamp portion 5 when gripping the workpiece 12 are balanced, the total compressive force from all the gripping members 41 is equal to the compressive force from the fixed clamp portion 5.

[0082] Note that, as shown in FIG. 7, in order for a plurality of gripping members 41 to apply an axially uniform compressive force to the end surface of the workpiece 12 from a plurality of locations when all the gripping members 41 grip the workpiece 12, it is reasonable that the plurality of gripping members 41 are evenly distributed in the circumferential direction at positions equidistant from the center of the end surface of the follow clamp portion 4 in the radial direction (radius direction). In the drawing, four rod (pin)-shaped gripping members 41 are arranged, but the number is arbitrary. If the gripping member 41 is rod-shaped, at least three are sufficient. If the gripping member 41 is a curved or bent plate shape, at least two are sufficient.

[0083] When a plurality of gripping members 41 grip the end face of the workpiece 12, the pressure of the pressure fluid is adjusted so that an appropriate hydraulic pressure necessary for gripping acts on each gripping member 41. After the grinding of the circumferential surface of the workpiece 12 is completed, when releasing the grip on the workpiece 12 by the plurality of gripping members 41, the pressure fluid is returned from the pressure fluid supply pipe 95 to the tank 99 by releasing the hydraulic pump 96, and the pressure acting on the back surface of each gripping member 41 is released, and the follow clamping portion 4 retreats from the workpiece 12.

[0084] Each gripping member 41 is free to move axially when the hydraulic pressure is released. However, by interposing a spring around the gripping member 41 as described above, the gripping member 41 can be automatically immersed (restored) into the storage portion 42 when the hydraulic pressure is released. The restoring force (biasing force) of the spring is set smaller than the force by the hydraulic pressure acting on the back surface of each gripping member 41.

[0085] When the workpiece 12 is gripped by the follow clamping portion 4 and the fixed clamping portion 5, the grinding unit 11 shown in FIGS. 1, 3, and 9 linearly moves in the longitudinal direction on the support base 2 by the rotation of the motor 114 as a linear driving device connected thereto. Specifically, when the motor 114 rotates, simultaneously with the movement of the ball screw 115 that linearly moves in conjunction with the rotation, the grinding unit 11 integrated with the nut screwed to the ball screw 115 moves in the reciprocating direction of the movable side presser unit 9.

[0086] As a result of the grinding unit 11 moving toward the movable side presser unit 9, the fixed clamping portion 5, the workpiece 12, and the follow clamping portion 4 are taken into the inside of the liquid-proof box 111 attached to the grinding unit 11 and surrounded by the liquid-proof box 111. In a state where the fixed clamping portion 5, the workpiece 12, and the follow clamping portion 4 are surrounded by the liquid-proof box 111, the grinding wheel 112 mounted in the liquid-proof box 111 shown in FIG. 10 contacts the circumferential surface of the rotating workpiece 12 while rotating, so that the circumferential surface of the workpiece 12 is ground or the like. At this time, the workpiece 12 is maintained at a temperature below a certain level by the coolant sprayed from the coolant nozzle 113.

[0087] On the wall plate 111a on the movable-side presser unit 9 side of the liquid-proof box 111, as shown in Fig. 10-(b), when the grinding unit 11 moves toward the movable-side presser unit 9, an opening 111b having a shape corresponding to the cross-sectional shape of the follower clamp portion 4 is formed to take at least a part of the axial direction of the follower clamp portion 4 into the liquid-proof box 111. Around the opening 111b on the inner peripheral surface of the wall plate 111a, a liquid-proof brush 117 is installed to prevent the coolant from the coolant nozzle 113 from spraying out of the liquid-proof box 111 when the follower clamp portion 4 enters the liquid-proof box 111 from the opening 111b.

[0088] With the fixed clamp portion 5 to the follower clamp portion 4 taken into the liquid-proof box 111, the support portions 6 and 7 are rotated around the axis by driving the work rotation motors 98 and 104 as the rotation driving devices attached to the rear sides of the movable-side presser unit 9 and the fixed-side presser unit 10 shown in Figs. 1 and 2, respectively, and the follower clamp portion 4 and the fixed clamp portion 5 are rotated together with the work 12. The drive shafts of the work rotation motors 98 and 104 are connected to each other within the movable-side presser unit 9 and the fixed-side presser unit 10, and by synchronizing the work rotation motors 98 and 104, they rotate at the same speed simultaneously.

[0089] When the work 12 rotates around the axis together with the support portions 6 and 7, grinding or polishing of the peripheral surface of the work 12 by the grinding wheel 112 described above is performed. When grinding the peripheral surface of the work 12, the grinding wheel 112 is rotated in the direction opposite to the rotation of the work 12. In Figs. 9 and 10, 116 indicates a notch grinding wheel for forming a groove in the axial direction of the work 12 with the rotation of the work 12 stopped.

Explanation of Reference Numerals

[0090] 1... Work grinding device, 2... Support base, 3... Gripping device, 4... One clamp portion (follower clamp portion), 41... Gripping material, 42... Storage portion, 43... Detection material, 5... The other clamp portion (fixed clamp portion), 6... Support part (of one clamping part), 7... Support part (of the other clamping part), 8... Linear drive device, 81... Motor, 82... Drive shaft, 83... Drive gear, 84... Driven gear, 85... Ball screw, 86... Nut, 9... Movable side presser unit, 91... Main body part, 92... Control part, 93... Guide, 94... Sensor, 95... Hydraulic fluid supply pipe, 96... Hydraulic pump, 97... Control valve, 98... Work rotation motor (rotation drive device), 99... Tank, 10... Fixed side presser unit, 101... Control part, 102... Air supply pipe, 103... Sensor, 104... Work rotation motor (rotation drive device), 11... Grinding unit, 111... Liquid-proof box, 111a... Wall plate, 111b... Opening, 112... Grinding wheel, 113... Cooling nozzle, 114... Motor, 115... Ball screw, 116... Notch grinding wheel, 117... Liquid-proof brush, 12... Workpiece, 12A... Supported material, 12A1... Projection.

Claims

1. (delete)

2. (delete)

3. A pair of clamping parts, supported on the support portion, are positioned opposite each other in the longitudinal direction of the support base, gripping the workpiece when they are close together, and rotatable together with the workpiece around its axis while gripping it. A rotational drive device that rotates each of the pair of clamping parts that grip the workpiece together with the support part around the axis of the clamping part, The system includes a linear drive device that moves at least one of the pair of clamp portions, together with the support portion that supports the other clamp portion, in a linear motion in the longitudinal direction relative to the support base, Of the pair of clamping sections, either one of the clamping sections or the other clamping section has a plurality of independent gripping members as a follow-up clamping section. The plurality of gripping members are housed within the follow-up clamp portion so as to be able to extend and retract from the end face of the follow-up clamp portion, and when the workpiece is gripped in the axial direction between the other clamp portion or the end face of the one clamp portion, the axial tip faces of all the gripping members grip the workpiece together with the end face of the other clamp portion or the one clamp portion. A sensing element is installed on the workpiece-side end face of the tracking clamp portion, which contacts the end face of the workpiece when the tracking clamp portion moves toward the workpiece, and transmits the contact signal to the linear drive device. A gripping device in a workpiece grinding apparatus, characterized in that, when the entire gripping material is immersed in the follow-up clamp portion, the tip surface of the detection material on the workpiece side is located closer to the workpiece than the tip surface of the entire gripping material on the workpiece side.

4. The gripping device in the workpiece grinding apparatus according to claim 3, characterized in that when the entire gripping material is extended, the tip surface of the entire gripping material on the workpiece side is located closer to the workpiece than the tip surface of the detection material on the workpiece side.

5. The gripping device in a work grinding apparatus according to claim 3 or 4, characterized in that the end of the gripping material on the workpiece side has a shape in which the cross-sectional area perpendicular to the axis of the gripping material decreases from the support side to the workpiece side.

6. The gripping device in a workpiece grinding apparatus according to claim 3 or 4, characterized in that the other clamping portion that is paired with the following clamping portion, or the end face of one of the clamping portions on the side of the following clamping portion, has a flat surface perpendicular to the axis of the workpiece.

Images