Work holding device and processing device

Abstract

To provide a workpiece holding device having a simple structure.SOLUTION: A workpiece holding device includes rolling rollers 30 each of which is rotatably supported by a workpiece holding body 14 so as to slidably contact with an outer peripheral surface Wb of a workpiece W in a rollable manner. A rotation axis Cr of the rolling roller 30 inclines having a predetermined angle around a radius line R of a workpiece W, which passes a contact point between the workpiece W coaxially held by the workpiece holding body 14 and the rolling roller 30, with reference to a state that a rotation axis Cr of the rolling roller 30 is arranged parallel to a rotation axis Ct of the workpiece holding body 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a workpiece holding device and a processing device, and more particularly to a workpiece holding device for holding a workpiece on a workpiece holder in a processing device such as a machine tool, and a processing device. [Background technology]

[0002] In a surface grinding machine, a holding device for holding a workpiece, which is an object to be ground, on a work table is known to use a magnetic chuck that magnetically attracts and holds the workpiece to the work table by energizing it (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-202275 [Patent Document 2] Patent Publication No. 2021-137950 Summary of the Invention [Problem to be solved by the invention]

[0004] Electromagnetic workpiece holding devices such as magnetic chucks require complex workpiece holders and peripheral structures, requiring time for maintenance, and are unable to hold non-magnetic workpieces such as ceramics.

[0005] The problem to be solved by the present invention is to provide a workpiece holding device that is simple in structure and easy to maintain, and that can also hold non-magnetic workpieces. [Means for solving the problem]

[0006] A work holding device according to one embodiment of the present invention is a work holding device (10) for holding a work (W) having a circular outer peripheral surface (Wb) on a work holder (14), and has at least one rolling roller (30) rotatably supported on the work holder so as to be in rolling and sliding contact with the outer peripheral surface of the work, and the rotation axis (Cr) of the rolling roller is inclined at a predetermined angle around a radius line (R) of the work that passes through the contact point between the work, which is held coaxially by the work holder, and the rolling roller, based on a state parallel to the rotation axis (Ct) of the work holder.

[0007] According to this configuration, the workpiece is held on the workpiece holder by the rolling rollers, which makes the structure simple and easy to maintain. Furthermore, according to this configuration, it is also possible to hold non-magnetic workpieces.

[0008] In the above workpiece holding device, the rolling rollers are provided at least at three locations equidistantly spaced around the rotation axis of the workpiece holding body.

[0009] With this configuration, an unbalanced load is not applied to the workpiece holder.

[0010] In the above work holding device, the rolling roller is provided so as to be displaceable in a direction away from and toward the outer peripheral surface of the work, and has a biasing member (48) that biases the rolling roller in a contact direction in which it contacts the outer peripheral surface of the work.

[0011] This configuration ensures that the rolling rollers come into contact with the outer peripheral surface of the workpiece.

[0012] The above-mentioned work holding device has at least one swing lever swingably mounted on the work holding body, the swing lever including one end that is displaceable in a direction radially away from the outer peripheral surface of the work, and the rolling roller is rotatably mounted on the one end of the swing lever.

[0013] This configuration increases the degree of freedom in arranging the rolling rollers relative to the workpiece holder.

[0014] In the above workpiece holding device, the swing lever is provided to be swingable at least at three positions equidistantly spaced about the rotation axis of the workpiece holding body.

[0015] With this configuration, an unbalanced load is not applied to the workpiece holder.

[0016] The workpiece holding device has a biasing member (48) that biases the rolling roller in a contact direction in which the rolling roller contacts the outer peripheral surface of the workpiece via the swing lever.

[0017] This configuration ensures that the rolling rollers come into contact with the outer peripheral surface of the workpiece.

[0018] In the above-mentioned work holding device, the oscillating lever has another end (26B) located radially outward from the oscillating center relative to the one end, and adjacent other ends of the oscillating lever are connected to each other by link elements (42, 44) extending radially outward from the outer peripheral surface of the work.

[0019] According to this configuration, centering is automatically performed so that the rotation axis of the workpiece on the workpiece holder coincides with the rotation axis of the workpiece holder.

[0020] The work holding device has an intermediate arm rotatably mounted on the work holding body at an intermediate position around the rotation axis of the work holding body between adjacent swing levers, and a link element (42, 44) pivotally connecting the intermediate arm and the swing lever adjacent to the intermediate arm to each other.

[0021] According to this configuration, centering is automatically performed so that the rotation axis of the workpiece on the workpiece holder coincides with the rotation axis of the workpiece holder, and the workpiece holding device can be made smaller.

[0022] In the above workpiece holding device, the rolling roller has an outer periphery (30C) made of elastomer.

[0023] According to this configuration, the elasticity of the elastomer ensures that the rolling rollers come into contact with the outer circumferential surface of the workpiece.

[0024] In the above workpiece holding device, the rolling roller has a crown shape.

[0025] According to this configuration, even if the generatrix of the rolling roller is not highly parallel to the generatrix of the workpiece, the rolling roller can be pressed against the outer peripheral surface of the workpiece without any inclination component occurring.

[0026] A machining apparatus according to one embodiment of the present invention includes a workpiece holding device according to any of the above-described embodiments, and a machining tool that comes into contact with a workpiece placed on the workpiece holder to machine the workpiece.

[0027] According to this configuration, the structure of the processing device including the workpiece holding device is simplified, and maintenance is also facilitated. [Effects of the Invention]

[0028] The workpiece holding device according to the present invention has a simple structure and is easy to maintain. Furthermore, the workpiece holding device according to the present invention can also hold non-magnetic workpieces. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view showing one embodiment of a workpiece holding device and a processing device according to the present invention; [Figure 2] 1 is a plan view of a workpiece holding device according to an embodiment of the present invention; [Figure 3] FIG. 10 is a perspective view showing the inclination of the rolling rollers of the workpiece holding device according to the present embodiment; [Figure 4] FIG. 10 is an explanatory diagram (front view) illustrating the operation of the workpiece holding device according to the present embodiment. [Figure 5]1 is an enlarged cross-sectional view of one embodiment of a rolling roller used in a workpiece holding device according to the present embodiment; [Figure 6] 10 is an enlarged cross-sectional view of another embodiment of the rolling roller used in the workpiece holding device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an embodiment in which a workpiece holding device according to the present invention is applied to a surface grinding machine (machining machine) will be described with reference to the drawings.

[0031] As shown in FIGS. 1 and 2, the workpiece holding device 10 has a base 12 and a workpiece holder 14 provided on the base 12 so as to be rotatable about a vertical rotation axis Ct.

[0032] The workpiece holder 14 is a disk-shaped rotary table, and includes a workpiece placing table 15 having a flat, horizontal upper surface 15A on which the workpiece W is placed, and a shelf portion 17 provided radially outward of the workpiece placing table 15.

[0033] The workpiece holder 14 is driven to rotate by an electric motor 16 (see Figures 3 and 4) attached to the base 12 around a vertical rotation axis Ct that is perpendicular to the upper surface 15A, in a predetermined direction relative to the base 12, which in this embodiment is clockwise as viewed in Figures 1 and 2.

[0034] The workpiece W is disk-shaped and has a flat lower surface Wa that is in planar contact with the upper surface 15A of the workpiece mounting table 15, and a circular outer peripheral surface (circumferential surface) Wb. The workpiece W is placed on the upper surface 15A of the workpiece mounting table 15 so that its central axis Cw is coaxial with the rotation axis Ct of the workpiece holder 14. The workpiece W may be made of either a magnetic or non-magnetic material.

[0035] A grinding wheel 20 (see FIG. 1) supported by a horizontal rotating shaft 18 is disposed above the workpiece mounting table 15. The central axis Cg of the rotating shaft 18 extends in a horizontal direction perpendicular to the rotation axis Ct of the workpiece holder 14. The grinding wheel 20 is a rotary tool, and is driven to rotate around the central axis Cg of the rotating shaft 18 in a clockwise direction when viewed from the front of the rotating shaft 18 by an electric motor (not shown) that drives the rotating shaft 18 to rotate.

[0036] The grinding wheel 20 is movable up and down to provide a grinding allowance to the workpiece W by a grinding wheel head (not shown) that rotatably supports the rotary shaft 18, and is also movable in the radial direction of the workpiece holder 14 (the axial direction of the grinding wheel 20) to traverse the workpiece W. In other words, the grinding wheel 20 is a processing tool of the processing device, and comes into contact with the workpiece W placed on the workpiece placing table 15 to grind the workpiece W.

[0037] The shelf portion 17 has a horizontal, annular upper surface 17A that extends so as to surround the outside of the workpiece placing table 15. Shafts 24 are vertically attached to the upper surface 17A of the shelf portion 17 at three locations equally spaced (at 120-degree intervals) around the rotation axis Ct of the workpiece holder 14. A swing lever 26 is attached to each shaft 24 so as to be swingable around the central axis of the corresponding shaft 24, in other words, around an axis parallel to the rotation axis Ct of the workpiece holder 14.

[0038] The swing lever 26 includes an inner end (one end) 26A located closer to the workpiece mounting table 15 than the shaft body 24, and an outer end (the other end) 26B located farther from the workpiece mounting table 15 than the shaft body 24.

[0039] A rolling roller 30 is attached to the inner end 26A of each swing lever 26 by a roller shaft 28 so as to be rotatable about the central axis Cr of the roller shaft 28. The lever lengths between each roller shaft 28 and the corresponding shaft body 24 are equal to each other.

[0040] Since the central axis Cr of the roller shaft 28 is the same as the rotation axis of the rolling roller 30, the central axis Cr of the roller shaft 28 may hereinafter be referred to as the rotation axis Cr of the rolling roller 30.

[0041] Each rolling roller 30 has the same diameter, and as shown in Figure 5, has a metal boss member 30B having an axial hole 30A through which the roller shaft 28 passes, and an elastomer annular outer peripheral member 30C fixed to the outer periphery of the boss member 30B.

[0042] Each rolling roller 30 is displaced in the radial direction of the workpiece placing table 15, in other words, in the radial direction of the workpiece W on the workpiece placing table 15, by the swing (rotation) of the swing lever 26 about the shaft 24 as the swing center. As a result, each rolling roller 30 is displaced in a direction of moving toward or away from the outer peripheral surface Wb of the workpiece W on the workpiece placing table 15 in the radial direction of the workpiece W.

[0043] The outer peripheral surface of each rolling roller 30 faces radially the outer peripheral surface Wb of the workpiece W placed on the workpiece placing table 15. Each rolling roller 30 has its outer peripheral surface in sliding contact with the outer peripheral surface Wb of the workpiece W, and rolls around the central axis Cr due to relative rotational displacement with the workpiece W. The point of contact between each rolling roller 30 and the workpiece W is located on the leading side of the rotational displacement with respect to the workpiece W on the workpiece placing table 15 (leading side in the rotational direction) relative to the position of the shaft 24.

[0044] Since the inner end 26A is located on the leading side of the shaft 24 in the rotation direction of the workpiece holder 14, each swing lever 26 tilts backward in response to relative displacement of the workpiece W in the circumferential direction.

[0045] 3, the rotation axis Cr of each rolling roller 30 is inclined at a predetermined angle θ around a radius R of the workpiece W that passes through a contact point A between the workpiece W held coaxially by the workpiece holder 14 and the rolling roller 30, with the reference state (indicated by reference line B) being parallel to the rotation axis Ct of the workpiece holder 14. In other words, the angle formed by the reference line B and the rotation axis Cr is the predetermined angle θ.

[0046] In other words, the rotation axis Cr of each rolling roller 30 and the rotation axis Ct of the work holder 14, in other words, the rotation axis Cr and the central axis Cw of the work W on the work mounting table 15, are in a twisted relationship in which they are not parallel and do not intersect.

[0047] The inclination direction of the rotation axis Cr of each rolling roller 30 is determined to be a direction that presses the workpiece W against the upper surface 15A of the workpiece mounting table 15 with respect to the direction of rotational displacement of the workpiece W relative to the rolling roller 30. In this embodiment, assuming that the direction of rotational displacement of the workpiece W relative to the rolling roller 30 is counterclockwise, the inclination direction of the rotation axis Cr of each rolling roller 30 is a direction in which a rotational force Fa having a vector perpendicular to the rotation axis Cr acts on the rolling roller 30 when the rolling roller 30 rolls in a clockwise direction about the rotation axis Cr due to the rotational displacement of the workpiece W relative to the rolling roller 30, generates a component force Fb of a downward vector that presses the lower surface Wa of the workpiece W against the upper surface 15A of the workpiece mounting table 15, as shown in Figure 4.

[0048] The three rocking levers 26 are connected to each other so that adjacent ones are connected by a connecting link mechanism 32 provided on the shelf portion 17. The connecting link mechanism 32 has three intermediate arms 36 and three pairs of link elements 42, 44. Vertical shafts 34 for the connecting link mechanisms 32 are installed on the shelf portion 17 at intermediate positions around the rotation axis Ct between adjacent rocking levers 26.

[0049] Each intermediate arm 36 includes a base end 36A that is rotatably attached to the shelf portion 17 by a vertical shaft 34. Each intermediate arm 36 pivotally supports the ends of adjacent link elements 42, 44 by vertical pivots 38, 40 provided on both sides of the intermediate portion between the base end 36A and the free end 36B. In other words, each pair of link elements 42, 44 pivotally connects the intermediate arm 36 and the outer end 26B of the swing lever 26 adjacent to that intermediate arm 36 by the pivots 38, 40. The link elements 42, 44 extend approximately in the circumferential direction of the workpiece W radially outward from the outer circumferential surface Wb of the workpiece W.

[0050] The connecting link mechanism 32 includes two link elements 42, 44 that connect the intermediate arm 36 and the outer end 26B of the swing lever 26 adjacent to the intermediate arm 36, and therefore has a generally hexagonal shape that surrounds the work holder 14, and has a smaller outer shape (polygonal shape) than the triangular shape that surrounds the workpiece placing table 15 without the intermediate arm 36. This makes the work holding device more compact than when the intermediate arm 36 is not present.

[0051] A spring receiving member 46 is attached to the shelf portion 17 at a position offset by a predetermined angle from the free end 36B of each intermediate arm 36 toward the lagging side (opposite the leading side) in the rotational direction of the work holder 14. A compression coil spring 48 is attached as a biasing member between each spring receiving member 46 and the free end 36B of the corresponding intermediate arm 36.

[0052] The compression coil springs 48 bias the swing levers 26 equally in the clockwise direction around the central axis of the shaft 24 via the intermediate arm 36 and the link elements 42, 44. Due to the bias of the swing levers 26, the rolling rollers 30 are biased in a contact direction so as to come into contact with the outer peripheral surface Wb of the workpiece W, and the outer peripheral surfaces are resiliently pressed against the outer peripheral surface Wb of the workpiece W equally.

[0053] The work W on the work table 15 is automatically centered so that its central axis Cw coincides with the rotation axis Ct of the work holder 14, thanks to three rolling rollers 30 arranged at equal intervals at three locations around the rotation axis (central axis) of the work table 15, each of which has the same diameter and whose outer peripheral surface contacts the outer peripheral surface Wb of the work W, and which are connected to each other by a connecting link mechanism 32 via swing levers 26 of the same length.

[0054] In this centered state, the rolling rollers 30 are resiliently and evenly pressed against each other by the spring force of the compression coil springs 48 toward the outer peripheral surface Wb of the workpiece W. Furthermore, because the three rolling rollers 30 are spaced equally apart around the rotation axis Ct of the workpiece holder 14, no radially unbalanced load acts on the workpiece W.

[0055] Next, the action of pressing the workpiece W against the workpiece table 15 by the rolling rollers 30 will be described.

[0056] With the rotation of the workpiece holder 14 stopped, the grinding wheel 20 is driven to rotate clockwise around the central axis Cg, and when the grinding wheel 20 moves downward and comes into contact with the workpiece W on the workpiece mounting table 15, a force acts on the workpiece W to rotate it counterclockwise around the central axis Cw relative to the workpiece mounting table 15. This causes the workpiece W to be rotationally displaced relative to the workpiece mounting table 15. Due to this rotational displacement of the workpiece W, each rolling roller 30 rolls slightly counterclockwise around the rotation axis Cr while being pressed against the outer peripheral surface Wb of the workpiece W.

[0057] 4 acts on the workpiece W, based on the fact that the central axis Cr of each rolling roller 30 is inclined as described above. As a result, the lower surface Wa of the workpiece W is pressed against the upper surface 15A of the workpiece mounting table 15, with the workpiece W being slightly rotationally displaced relative to the workpiece mounting table 15, and the workpiece W is fixed to the workpiece holder 14.

[0058] After this, when the workpiece holder 14 is driven to rotate clockwise around the rotation axis Ct by the electric motor 16, the workpiece W does not undergo rotational displacement relative to the workpiece holder 14, but rotates clockwise around the rotation axis Ct integrally with the workpiece holder 14.

[0059] In this state, the grinding wheel 20 moves along its axis, thereby grinding the workpiece W.

[0060] Furthermore, the grinding wheel 20 may come into contact with the workpiece W under a condition in which the workpiece holder 14 is driven to rotate clockwise around the rotation axis Ct and the workpiece W is rotating on the mounting table 15 in the same direction.

[0061] As described above, the work holding device 10 of this embodiment does not rely on electromagnetic attraction to secure the workpiece W to the work holder 14, so whether the workpiece W is made of a magnetic or non-magnetic material, the workpiece W can be secured to the work holder 14. Because the work holding device 10 is mechanical, it has a simpler structure and is easier to maintain than electromagnetic or negative pressure attraction types.

[0062] Each rolling roller 30 is resiliently pressed toward the outer peripheral surface Wb of the workpiece W by the spring force of the compression coil spring 48, and is resiliently pressed against the outer peripheral surface Wb of the workpiece W due to the elastic deformation of the elastomer that constitutes the outer peripheral member 30C. This ensures that each rolling roller 30 slides against the outer peripheral surface Wb of the workpiece W, and ensures that the workpiece W is fixed to the workpiece holder 14 through self-centering.

[0063] Since each swing lever 26 is inclined backward relative to the circumferential movement of the workpiece W, the relative movement between the swing lever 26 and the workpiece W increases the biasing force of the compression coil spring 48.

[0064] Another embodiment of the rolling roller 30 will be described with reference to Fig. 6. In Fig. 6, parts corresponding to those in Fig. 5 are given the same reference numerals as those in Fig. 5, and descriptions thereof will be omitted.

[0065] In the rolling roller 30 of this embodiment, the outer peripheral member 30C made of elastomer has a crown shape in which the outer diameter increases from the axial end side toward the center in the axial direction.

[0066] Because the rolling roller 30 has a crown shape, even if the generatrix of the rolling roller 30 is not highly parallel to the generatrix of the workpiece W (the line segment in the axial direction of the outer circumferential surface), the rolling roller 30 can be pressed against the outer circumferential surface Wb of the workpiece W without generating an inclination component. Also, when the rolling roller 30 is pressed against the outer circumferential surface Wb of the workpiece W, the elastic deformation of the outer circumferential member 30C gradually increases, and the rolling roller 30 can be pressed resiliently against the outer circumferential surface Wb of the workpiece W well.

[0067] Although the description of the specific embodiment has been completed above, the present invention is not limited to the above embodiment and can be widely modified and implemented.

[0068] For example, the number of rolling rollers 30 is not limited to three, but may be one, two, or three or more. The rolling rollers 30 may be provided directly on the workpiece holder 14 so as to be movable in the radial direction of the workpiece holder 14 and rollable about the central axis Cr.

[0069] The biasing member is not limited to the compression coil spring 48, but may be a tension coil spring or other spring that biases the rolling roller 30 in the contact direction to contact the outer peripheral surface Wb of the workpiece W, an air-filled air spring, an actuator, etc.

[0070] The intermediate arm 36 of the connecting link mechanism 32 is not essential, and adjacent rocking levers 26 may be directly connected by a link element.

[0071] A magnetic chuck may be incorporated into the workpiece holder 14, and holding of the workpiece W by the rolling rollers 30 and holding of the workpiece W by the magnetic chuck may be combined.

[0072] The workpiece holding device is not limited to being used to hold a workpiece in a surface grinder, but can also be used to hold a workpiece in various machine tools such as milling machines, and in various other industrial machines. [Explanation of symbols]

[0073] 10: Work holding device 12: Foundation 14: Work holder 15: Workpiece placement table 15A:Top surface 16: Electric motor 17:Shelf 17A:Top surface 18: Rotation axis 20: Grinding wheel 24: Shaft 26: Oscillating lever 26A: Inner end (one end) 26B: Outer end (other end) 28: Roller shaft 30: Roller 30A: Shaft hole 30B: Boss member 30C: Peripheral part (periphery) 32: Connecting link mechanism 34: Vertical axis 36: Intermediate arm 36A: Proximal end 36B: Free end 38: Axis 40: Axis 42: Link element 44: Link element 46: Spring support member 48: Compression coil spring A: Contact point B:Reference line Cg: Central axis line Cr: Central axis (axis of rotation) Ct: Rotation axis Cw: Central axis line Fa: rotational force Fb: component force R: Radius line W: Work Wa: bottom Wb: Outer surface θ: angle

Claims

1. A workpiece holding device for holding a workpiece having a circular outer peripheral surface on a workpiece holder, At least one rolling roller is rotatably supported by the workpiece holder so as to be in rolling and sliding contact with the outer peripheral surface of the workpiece, A work holding device in which the rotation axis of the rolling roller is inclined at a predetermined angle around a radius of the work that passes through the contact point between the work, which is held coaxially by the work holder, and the rolling roller, with respect to a state that is parallel to the rotation axis of the work holder.

2. 2. A workpiece holding device according to claim 1, wherein said rolling rollers are provided at least at three locations equidistantly spaced about the rotation axis of said workpiece holder.

3. The rolling roller is provided so as to be displaceable in a direction in which the rolling roller approaches and separates from the outer peripheral surface of the workpiece, 3. The workpiece holding device according to claim 1, further comprising a biasing member that biases the rolling rollers in a contact direction so as to contact the outer circumferential surface of the workpiece.

4. The workpiece holder has at least one swing lever swingably provided thereon, the swing lever including one end portion displaceable in a direction radially approaching and separating from the outer peripheral surface of the workpiece, 2. The workpiece holding device according to claim 1, wherein the rolling roller is rotatably provided at the one end of the swing lever.

5. 5. The workpiece holding device according to claim 4, wherein said swing lever is swingably provided at at least three positions equidistantly spaced about the rotation axis of said workpiece holder.

6. 6. The workpiece holding device according to claim 4, further comprising a biasing member that biases the rolling roller in a direction of contacting the outer peripheral surface of the workpiece via the swing lever.

7. A workpiece holding device as described in claim 5, wherein the oscillating lever has another end portion located radially outward from the oscillating center relative to the one end portion, and adjacent other ends of the oscillating levers are connected to each other by a link element.

8. an intermediate arm rotatably provided on the workpiece holder at an intermediate position around the rotation axis of the workpiece holder between adjacent swing levers; 6. The workpiece holding device according to claim 5, further comprising a link element that pivotally connects the intermediate arm and the swing lever adjacent to the intermediate arm.

9. 3. The workpiece holding device according to claim 1, wherein the rolling roller has an outer periphery made of elastomer.

10. The workpiece holding device according to claim 9, wherein the rolling roller has a crown shape.

11. A work holding device according to claim 1, 2, 4, 5, 7 or 8; a processing tool that comes into contact with the workpiece placed on the workpiece holder to process the workpiece.

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