Holding device

Abstract

To move a bearing along a cam groove smoothly.SOLUTION: A holding device includes a conversion part which converts rotational driving of a drive shaft into linear motion of a holding part. The conversion part has: a cam formed with a cam groove which is recessed from one end surface to the other end surface; and a bearing inserted into the cam groove. An end surface of the bearing is disposed spaced apart from the one end surface to the other end surface side in an extension direction of the drive shaft.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a gripping device.

Background Art

[0002] Conventionally, an electric gripper having a mechanism for converting the rotational drive of an output shaft into the linear motion of a gripping member has been known (see, for example, Patent Document 1). The above-described electric gripper has a cam having a cam groove and a bearing inserted into the cam groove.

[0003] In order to miniaturize the device, the bearing is disposed inside the cam groove such that the end surface of the cam and the end surface of the bearing coincide with each other in the gripping device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, before assembling the above-described electric gripper, for example, during the transportation of parts, there is a risk that small scratches are formed on the end surface of the cam in which the cam groove is formed due to contact between cams or contact between the cam and other parts. And when there is a scratch in the cam groove, there is a risk that the bearing is caught by the scratch when the bearing moves along the cam groove.

[0006] An object of the present invention is to provide a gripping device capable of smoothly moving a bearing along a cam groove.

Means for Solving the Problems

[0007] To solve the above-mentioned problems and achieve the objective, the gripping device according to the present invention includes a conversion unit that converts the rotational drive of the drive shaft into linear motion of the gripping portion, the conversion unit having a cam with a cam groove formed therein that is recessed from one end face toward the other end face, and a bearing inserted into the cam groove, the end face of the bearing being positioned on the other end face side in the extending direction of the drive shaft and spaced apart from the one end face.

[0008] According to the present invention, the bearing can be moved smoothly along the cam groove. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view of a gripping device according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view taken along arrow AA in Figure 1. [Figure 3] Figure 3 is a cross-sectional view taken along arrow BB in Figure 1. [Figure 4] Figure 4 is a plan view of the relay plate included in the gripping device according to this embodiment. [Figure 5] Figure 5 is a perspective view showing the inside of the gripping device according to the embodiment. [Figure 6] Figure 6 is a perspective view showing the inside of the gripping device according to the embodiment. [Figure 7] Figure 7 is a perspective view showing a cam attached to the drive shaft in a gripping device according to an embodiment. [Figure 8] Figure 8 is a perspective view showing the cam and bearing of the gripping device according to the embodiment. [Figure 9] Figure 9 is a cross-sectional view of the cam, bearing, and shaft included in the gripping device according to the embodiment. [Figure 10] Figure 10 is a cross-sectional view of the shaft and block included in the gripping device according to the embodiment. [Figure 11] Figure 11 is a perspective view showing the inside of the gripping device according to the embodiment. [Figure 12]Figure 12 is a perspective view illustrating the assembly of the conversion unit to the motor case in the gripping device according to this embodiment. [Figure 13] Figure 13 illustrates a jig used for assembling the gripping device according to the embodiment. [Figure 14] Figure 14 is a perspective view illustrating the assembly of the drive unit housing to the conversion unit in a gripping device according to an embodiment. [Modes for carrying out the invention]

[0010] The following describes an embodiment of the gripping device in detail based on the drawings. Note that the dimensional relationships and proportions of each element in the drawings may differ from reality. There may also be differences in dimensional relationships and proportions between different parts of the drawings.

[0011] [Embodiment] Figure 1 is a perspective view of the gripping device 1 according to the embodiment. Figure 2 is a cross-sectional view taken along arrow AA in Figure 1. Figure 3 is a cross-sectional view taken along arrow BB in Figure 1. Figure 4 is a plan view of the relay plate 3 included in the gripping device 1 according to the embodiment. Figure 5 is a perspective view showing the interior of the gripping device 1 according to the embodiment. Figure 6 is a perspective view showing the interior of the gripping device 1 according to the embodiment. Figure 7 is a perspective view showing the cam 41 attached to the drive shaft 211 in the gripping device 1 according to the embodiment. Figure 8 is a perspective view showing the cam 41 and bearing 42 included in the gripping device 1 according to the embodiment. Figure 9 is a cross-sectional view of the cam 41, bearing 42, and shaft 43 included in the gripping device 1 according to the embodiment. Figure 10 is a diagram illustrating the shaft 43 and block 44 included in the gripping device 1 according to the embodiment. Figure 11 is a perspective view showing the interior of the gripping device 1 according to the embodiment. In each drawing, for the sake of ease of explanation, the direction in which the drive shaft 211, which will be described later, extends is defined as the Z-axis direction, the direction perpendicular to the Z-axis direction is defined as the X-axis direction, and the direction perpendicular to both the Z-axis direction and the X-axis direction is defined as the Y-axis direction.

[0012] The gripping device 1 shown in FIG. 1 according to this embodiment is provided at the tip of a manipulator such as a robot arm and is used for a robot hand or the like that grips a workpiece (object to be gripped). As shown in FIGS. 2 and 3, the gripping device 1 includes a drive unit 2, an intermediate plate 3, and a conversion unit 4.

[0013] The drive unit 2 has a motor 21 and a drive unit housing 22. The motor 21 is a drive source and is electrically connected to a power source (not shown) via a connector C2 and an electric wire W2 shown in FIG. 1. The motor 21 shown in FIG. 2 has a drive shaft 211 that can be rotationally driven when power is supplied from the power source. In other words, the gripping device 1 includes a drive unit 2 having a drive shaft 211. When power is supplied from the power source, the motor 21 rotationally drives about the axis 211z of the drive shaft 211.

[0014] An engaging portion 211a is formed at one end of the drive shaft 211 in the extending direction (Z-axis direction). The engaging portion 211a is a recess that extends from one end face of the drive shaft 211 toward the other end face in the Z-axis direction.

[0015] The motor 21 also has a motor case 212 that houses the motor 21. The motor case 212 is formed in a rectangular parallelepiped shape as shown in FIG. 6 by, for example, a plurality of plate materials. A plurality of first screw holes Nu1 are formed at one end of the motor case 212 in the Z direction (see FIG. 5).

[0016] As shown in FIGS. 2 and 3, the drive unit housing 22 houses the motor case 212 and includes a side housing 221 and a bottom housing 222. The side housing 221 covers the periphery of the motor 21 in the X-axis and Y-axis directions, is formed in a rectangular tube shape, and has a pair of openings 221a and 221b in the Z-axis direction. Of the pair of openings 221a and 221b, the opening 221a located on the other side in the Z-axis direction is closed by the bottom housing 222. Of the pair of openings 221a and 221b, the opening 221b located on one side in the Z-axis direction is closed by a cam case 461a described later. As shown in FIG. 7, the side housing 221 has a third screw hole Nu3 at one end in the Z-axis direction.

[0017] The relay plate 3 is interposed between the cam case 461a and the motor case 212 described later. The relay plate 3 is made of, for example, stainless steel and is formed in a substantially rectangular plate shape. As shown in FIGS. 4 to 6, the relay plate 3 has a drive shaft insertion hole 3h1 through which the drive shaft 211 is inserted, a first bolt insertion hole 3h2 through which a first bolt Bo1 is inserted, and a second bolt insertion hole 3h3 through which a second bolt Bo2 is inserted.

[0018] The drive shaft insertion hole 3h1, the first bolt insertion hole 3h2, and the second bolt insertion hole 3h3 penetrate the relay plate 3 in the Z-axis direction. Further, the relay plate 3 according to the present embodiment has one drive shaft insertion hole 3h1, four first bolt insertion holes 3h2, and four second bolt insertion holes 3h3.

[0019] As described later, when the relay plate 3 is placed on the motor case 212 such that the first bolt insertion hole 3h2 and the first screw hole Nu1 coincide with each other in the X-axis and Y-axis directions, and the first bolt Bo1 and the first screw hole Nu1 are screwed together, the relay plate 3 is attached to the motor case 212. That is, the portion of the relay plate 3 where the four first bolt insertion holes 3h2 are formed is the position where the motor case 212 is attached.

[0020] As will be described later, when the cam case 461a is placed on the intermediate plate 3 such that the second bolt insertion hole 3h3 and the second screw hole Nu2 are aligned in the X-axis and Y-axis directions, the intermediate plate 3 is attached to the cam case 461a when the second bolt Bo2 and the second screw hole Nu2 are screwed together. In other words, the portion of the intermediate plate 3 where the four first bolt insertion holes 3h2 are formed is the position to which the cam case 461a is attached.

[0021] As shown in Figure 4, the first bolt insertion hole 3h2 is positioned to be close to the axis 211z of the drive shaft 211 in the radial direction. On the other hand, the second bolt insertion hole 3h3 is positioned to be further away from the axis 211z of the drive shaft 211 than the first bolt insertion hole 3h2 in the radial direction. In other words, in the relay plate 3 according to this embodiment, the position where the cam case 461a is attached is different from the position where the motor case 212 is attached. In the gripping device 1 according to this embodiment, the position where the cam case 461a is attached is located further outward than the position where the motor case 212 is attached, with respect to the axis 211z of the drive shaft 211 that penetrates the relay plate 3.

[0022] As shown in Figure 2, the conversion unit 4 includes a cam 41, a bearing 42, a shaft 43, a block 44, a gripping part 45, and a guide part 46. The conversion unit 4 converts the rotational drive of the drive shaft 211 into the linear motion of the gripping part 45. Note that the conversion unit 4 in this embodiment may be composed of other parts. The conversion unit 4 allows the pair of gripping parts 45 to move closer together and further apart along the X-axis direction. By bringing the pair of gripping parts 45 closer together, it grips the object to be gripped (workpiece), while by moving the pair of gripping parts 45 further apart, it releases the object to be gripped.

[0023] As shown in Figure 8, the cam 41 is formed in a disc shape, for example, having a through hole 41h. As shown in Figure 9, the drive shaft 211 of the motor 21 is inserted into the through hole 41h and fixed to the drive shaft 211. Such a cam 41 is formed by sintering using a mold molding method with an iron-based sintered material. In addition, the cam 41 has a cam groove 411 that is recessed in the Z-axis direction from one end face 411f1 to the other end face 411f2. In other words, the conversion unit 4 has a cam 41 with a cam groove 411 that is recessed from one end face 411f1 to the other end face 411f2.

[0024] As shown in Figure 8, the cam groove 411 extends circumferentially with respect to the axis 211z of the drive shaft 211. The distance between the axis 211z and the center of the cam groove 411 gradually increases as you move towards one end 411s, while the distance between the axis 211z and the center of the cam groove 411 gradually decreases as you move towards the other end 411e. The cam 41 according to this embodiment has a pair of cam grooves 411a and 411b.

[0025] The opening side of the cam groove 411, which is one end face 411f1 of the cam 41, is chamfered. This chamfering process creates an inclined surface 411f3 (see Figure 9) in the cam groove 411 with a length of, for example, 0.1 to 0.2 mm in the Z-axis direction. The inclined surface 411f3 is provided on both side walls of the cam groove 411 so as to face the direction of extension of the cam groove 411. Such inclined surfaces 411f3 facilitate the insertion of the bearing 42 into the cam groove 411 during the assembly of the gripping device 1, thereby improving work efficiency.

[0026] As shown in Figure 9, a bearing 42 is inserted into each of the pair of cam grooves 411. In other words, the conversion unit 4 has bearings 42 inserted into the cam grooves 411. The bearings 42 function as cam followers for the cam 41. A lubricant is also applied to the inner wall surface of the cam grooves 411. In this embodiment, a gripping device 1 having two bearings 42 has been described, but the number of bearings 42 can be changed as appropriate.

[0027] The other end of the shaft 43 is inserted into the bearing 42. More specifically, the other end of the shaft 43 is the lower end in the Z-axis direction, and the other end of the shaft 43 is press-fitted into the bearing 42 according to this embodiment. The end face 42f1 of the bearing 42 is positioned away from the other end face 411f2 in the Z-axis direction (the direction in which the drive shaft 211 extends) from the other end face 411f2. More specifically, the bearing 42 is positioned inside the cam groove 411 such that the end face 42f1 of the bearing 42 and the end face 411f1 of the cam 41 are offset in the Z-axis direction. The difference H1 between the end face 411f1 of the cam 41 and the end face 42f1 of the bearing 42 in the Z-axis direction is, for example, 0.5 mm. Therefore, in the gripping device 1 according to this embodiment, as shown in Figure 8, the end face 42f1 of the bearing 42 is located further below the lower end of the chamfered inclined surface 411f3 in the Z-axis direction. Furthermore, the widening portion 432 and recess 441, which will be described later, determine the position of the bearing 42 in the Z-axis direction, and as shown in Figure 9, a gap 42s is formed between the bottom surface 411f4 of the cam groove 411 and the bottom surface 42f2 of the bearing 42.

[0028] The shaft 43 is formed to extend in the Z-axis direction. One end 43e1 of the shaft 43 in the Z-axis direction is inserted into the bearing 42. The other end 43e2 of the shaft 43 in the Z-axis direction is inserted into the block 44 (see Figure 2). The shaft 43 according to this embodiment also has a shaft body portion 431, a widened portion 432 formed at the other end of the shaft body portion 431 and projecting radially outward from the circumferential surface of the shaft body portion 431, and an adhesive groove 433 recessed radially inward from the circumferential surface of the shaft body portion 431.

[0029] The adhesive groove 433 is formed, for example, to extend continuously around the shaft body 431 in the circumferential direction. As shown in Figure 10, the shaft 43 of this embodiment has two adhesive grooves 433 spaced apart, for example, in the Z-axis direction. In the radial direction of the shaft 43, a gap 43s larger than the gap formed between the shaft body 431 and the first through hole 44h1 is formed between the adhesive groove 433 and the first through hole 44h1. The widened portion 432 has a lower end surface 432f perpendicular to the extending direction of the drive shaft 211. The gripping device 1 according to this embodiment has a pair of shafts 43a and 43b.

[0030] As shown in Figure 1, the block 44 is formed in a substantially rectangular parallelepiped shape, and as shown in Figure 2, two through holes 44h1 and 44h2 are formed that penetrate the block 44 in the Z-axis direction. Of the two through holes 44h1 and 44h2, the other end of the shaft 43 in the Z-axis direction is inserted through the first through hole 44h1. After adhesive is applied to the adhesive groove 433 of the shaft body portion 431, the shaft 43 is inserted through the first through hole 44h1 of the block 44, and then the adhesive hardens in the gap 43s, fixing the other end of the shaft 43 to the block 44. Furthermore, as shown in Figure 10, since the outer circumferential surface of the shaft body portion 431 and the inner circumferential surface of the first through hole 44h1 are close together when the shaft 43 is inserted into the block 44, the shaft 43 can be positioned along the Z-axis direction relative to the block 44. Furthermore, of the two through holes 44h1 and 44h2, the shaft portion of the gripping portion 45 is inserted through the second through hole 44h2, thereby fixing the gripping portion 45 to the block 44.

[0031] Furthermore, the block 44 has a recess 441 formed in the portion where the first through hole 44h1 is formed, into which the widened portion 432 of the shaft 43 fits. The recess 441 has an upper end surface 441f perpendicular to the Z-axis direction. By fitting the widened portion 432 into the recess 441, the shaft 43 is positioned relative to the block 44 in the Z-axis direction, and thereby the bearing 42 is positioned relative to the block 44 in the Z-axis direction. The gripping device 1 according to this embodiment has a pair of blocks 44a and 44b.

[0032] A pair of gripping portions 45 are provided on the block 44 according to this embodiment. More specifically, the gripping portion 45 has a shaft portion inserted into the second through hole 44h2 of the block 44, and a claw portion (not shown) that can move closer to and further away from (hereinafter simply abbreviated as "approach and move away from") the object to be gripped in the X-axis direction. The gripping portion 45 can grip the object to be gripped (workpiece) by moving the pair of claw portions closer to and further away in the X-axis direction.

[0033] The guide portion 46 guides the pair of blocks 44 to move along the X-axis direction. As shown in Figure 1, the guide portion 46 has a base portion 461 which is composed of a part of the cam case 461a and a part of the guide rail 461b, which will be described later. The part of the cam case 461a that constitutes the base portion 461 is the case top plate 461a1, which will be described later, and the part of the guide rail 461b that constitutes the base portion 461 is the connecting portion 461b1, which will be described later. As shown in Figure 2, the base portion 461 has an inspection hole (through hole) 461h1 that penetrates the base portion 461 in the Z-axis direction, and a pair of guide holes 461h2 that sandwich the inspection hole 461h1 in the X-axis direction.

[0034] The inspection hole 461h1 is approximately the same diameter as the drive shaft 211 and is formed, for example, in a cylindrical shape, allowing the engaging portion 211a of the drive shaft 211 to be viewed from above in the Z-axis direction (one side in the extending direction). In other words, the conversion unit 4 has a base unit 461 in which an inspection hole (through hole) 461h1 is formed, allowing the engaging portion 211a of the drive shaft 211 to be viewed from above in the Z-axis direction (one side in the extending direction). In the gripping device 1, the center of the inspection hole 461h1 and the axis 211z of the drive shaft 211 coincide in the Z-axis direction.

[0035] As will be described later, a jig 5 is inserted into the inspection hole 461h1 during the assembly of the gripping device 1. The jig 5 is a so-called stepped shaft, and as shown in Figure 13, it has an engaged portion 51, an inspection hole opposing portion 52, and a gripping portion 53, and is formed to extend along the Z-axis direction.

[0036] The engaged portion 51 is capable of engaging with the engaged portion 211a formed on the drive shaft 211, and is formed at the tip of the jig 5 in the Z-axis direction. In this embodiment, the engaged portion 51 is formed, for example, in a cylindrical shape.

[0037] The inspection hole opposing portion 52 is formed adjacent to the engaged portion 51 in the Z-axis direction. When the engaged portion 51 is engaged with the engaging portion 211a, the outer circumferential surface of the inspection hole opposing portion 52 faces the inner circumferential surface of the inspection hole 461h1. In this embodiment, the inspection hole opposing portion 52 is formed in a cylindrical shape, for example, with a radial length longer than the radial length of the engaged portion 51.

[0038] The gripping portion 53 is the part that the worker grips when inserting the tip of the jig 5 into the inspection hole 461h1. The gripping portion 53 is formed adjacent to the inspection hole opposing portion 52 in the Z-axis direction. In this embodiment, the gripping portion 53 is formed in a cylindrical shape, for example, with a radial length longer than the radial length of the inspection hole opposing portion 52.

[0039] As shown in Figure 2, the guide holes 461h2 penetrate the base portion 461 in the Z-axis direction. Furthermore, the guide holes 461h2 extend along the X-axis direction. The shafts 43 are inserted through the guide holes 461h2. The guide holes 461h2 allow the shafts 43 to move linearly along the X-axis direction, while restricting the movement of the shafts 43 in the Y-axis direction.

[0040] As shown in Figure 1, the guide section 46 has a cam case 461a. The cam case 461a houses the cam 41. More specifically, the cam case 461a is formed in a box shape that covers one side of the cam 41 in the Z-axis direction, as well as both sides of the cam 41 in the X-axis and Y-axis directions, and has an opening on the other side in the Z-axis direction. The cam case 461a has a rectangular plate-shaped case top plate 461a1.

[0041] The case top plate 461a1 has a top plate inspection hole 461ah1 which constitutes the inspection hole 461h1 described above, and a top plate guide hole 461ah2 which constitutes the guide hole 461h2 described above.

[0042] Furthermore, the cam case 461a has a third bolt insertion hole 461ah3 that penetrates the cam case 461a in the Z-axis direction (see Figure 6).

[0043] Furthermore, as shown in Figure 3, the guide section 46 has a linear guide 4s which is composed of a block 44, a guide rail 461b, a steel ball 4Bo, and a steel ball housing groove 4D. The linear guide 4s facilitates the movement of the block 44 relative to the guide rail 461b.

[0044] The guide rail 461b has a rectangular plate-shaped connecting portion 461b1 and a pair of rail portions 461b2 that face each other in the Y-axis direction. The connecting portion 461b1 connects the pair of rail portions 461b2. The connecting portion 461b1 has a connecting portion inspection hole 461bh1 that constitutes the inspection hole 461h1 described above, and a connecting portion guide hole 461bh2 that constitutes the guide hole 461h2 described above.

[0045] The steel ball housing groove 4D houses the steel ball 4Bo and extends along the X-axis direction. The steel ball housing groove 4D is composed of a first groove 4D1 formed on the opposing surface of the block 44 in the rail portion 461b2 and a second groove 4D2 formed on the opposing surface of the block 44 in the rail portion 461b2.

[0046] Next, the assembly of the gripping device 1 having the above configuration will be explained using Figures 12 to 14. Figure 12 is a perspective view illustrating the assembly of the converter unit 4 to the motor case 212 in the gripping device 1 according to the embodiment. Figure 13 is a side view showing the jig 5 used for assembling the gripping device 1 according to the embodiment. Figure 14 is a perspective view illustrating the assembly of the drive unit housing 22 to the converter unit 4 in the gripping device 1 according to the embodiment.

[0047] First, the worker places the relay plate 3 on one side of the motor case 212 in the Z-axis direction, aligning the first bolt insertion hole 3h2 of the relay plate 3 (see Figure 5) with the first screw hole Nu1 of the drive unit 2 (see Figure 5).

[0048] Next, the worker inserts the tip of the first bolt Bo1 into the first bolt insertion hole 3h2, and then screws the first bolt Bo1 into the first screw hole Nu1, thereby fixing the relay plate 3 to the motor case 212 as shown in Figure 12. Then, the operator fixes the cam 41 to the tip of the drive shaft 211.

[0049] Next, the worker places the conversion unit 4 on one side of the relay plate 3 in the Z-axis direction. With the unit in this position, the tip of the jig 5 is inserted into the inspection hole 461h1. Then, as shown by the dashed line in Figure 13, the worker engages the engaged portion 51 of the jig 5 with the engaged portion 211a of the drive shaft 211, and positions the conversion unit 4 relative to the motor case 212 by facing the outer surface of the inspection hole opposing portion 52 of the jig 5 against the inner surface of the inspection hole 461h1.

[0050] In this state, the worker aligns the second bolt insertion hole 3h3 of the relay plate 3 (see Figure 6) with the second screw hole Nu2 of the conversion part 4 (see Figure 6).

[0051] Next, the worker inserts the tip of the second bolt Bo2 into the second bolt insertion hole 3h3, and then screws the second bolt Bo2 into the second screw hole Nu2 to fix the intermediate plate 3 to the conversion unit 4. As a result, the conversion unit 4 is assembled to the motor case 212 with the intermediate plate 3 in between.

[0052] Next, as shown in Figure 14, the worker places the conversion unit 4 on one side of the side housing 221 in the Z-axis direction, with the third bolt insertion hole 461ah3 of the conversion unit 4 aligned with the third screw hole Nu3 of the side housing 221.

[0053] Next, the worker inserts the tip of the third bolt Bo3 into the third bolt insertion hole 461ah3, and then screws the third bolt Bo3 into the third screw hole Nu3 to fix the side housing 221 to the motor case 212 and the converter 4.

[0054] Next, the worker places the side housing 221 on one side of the bottom housing 222 in the Z-axis direction, aligning the fourth bolt insertion hole 222h4 of the bottom housing 222 with the fourth screw hole (not shown) of the side housing 221.

[0055] Next, the worker inserts the tip of the fourth bolt Bo4 into the fourth bolt insertion hole 222h4, and then screws the fourth bolt Bo4 into the fourth screw hole (not shown) of the side housing 221, thereby fixing the bottom housing 222 to the side housing 221 and assembling the gripping device 1.

[0056] Next, we will describe the case in which the gripping device 1 having the above configuration grips an object to be gripped. In the initial state of the gripping device 1, as shown in Figure 1, a pair of blocks 44 are arranged at the furthest apart positions in the X-axis direction, and a bearing 42 is positioned on one end 411s side of a pair of cam grooves 411.

[0057] From this initial state, the motor 21 is driven, and the drive shaft 211 rotates around the axis 211z. The rotation of the drive shaft 211 causes the cam 41, which is fixed to the drive shaft 211, to rotate around the axis 211z.

[0058] Then, due to the rotational drive of the cam 41, the bearing 42 moves along the extending direction of the cam groove 411 from one end 411s to the other end 411e.

[0059] In this case, one end of the shaft 43 is press-fitted into the bearing 42, and the shaft 43 is allowed to move in the X-axis direction by the guide hole 461h2, while its movement in the Y-axis direction is restricted. As a result, the pair of blocks 44 move closer to each other in the X-axis direction. Along with the movement of the pair of blocks 44, the pair of gripping parts 45 also move closer to each other in the X-axis direction, and grip the object to be gripped that is placed between the pair of gripping parts 45. In such a gripping device 1, when releasing the object to be gripped, the motor 21 is driven in reverse, moving the pair of blocks 44 apart in the X-axis direction, and moving the pair of gripping parts 45 apart in the X-axis direction.

[0060] As described above, the gripping device 1 according to this embodiment has the following configuration. The end face 42f1 of the bearing 42 is positioned on the other end face 411f2 side in the extending direction of the drive shaft 211, spaced apart from the one end face 411f1. Before the assembly of the gripping device 1, for example during parts transport, small scratches may be formed on the one end face 411f1 of the cam 41, where the cam groove 411 is formed, due to contact between the cams 41 or contact between other parts. However, with the above configuration, the gripping device 1 according to this embodiment can suppress the formation of scratches on the inner circumferential surface of the cam groove 411 that the bearing 42 contacts. As a result, the gripping device 1 according to this embodiment can suppress contact between the bearing 42 and scratches on the inner circumferential surface of the cam groove 411, allowing the bearing 42 to move smoothly along the cam groove 411.

[0061] The gripping device 1 according to this embodiment has the following configuration. The shaft 43 has a widened portion 432 that protrudes radially outward, and the block 44 has a recess 441 into which the widened portion 432 engages. Therefore, the gripping device 1 according to this embodiment positions the shaft 43 relative to the block 44 in the Z-axis direction using the widened portion 432 and the recess 441, thereby positioning the bearing 42 relative to the block 44 in the Z-axis direction. In other words, the gripping device 1 according to this embodiment can easily position the bearing 42 relative to the block 44 using the widened portion 432 and the recess 441.

[0062] The gripping device 1 according to this embodiment has the following configuration. The drive shaft 211 has an engaging portion 211a formed at one end in the extending direction, and the conversion portion 4 has a base portion 461 in which an inspection hole (through hole) 461h1 is formed, which allows the engaging portion 211a of the drive shaft 211 to be visible from one side in the extending direction. Therefore, when assembling the gripping device 1 according to this embodiment, the worker can see the inspection hole 461h1 from above in the Z-axis direction and see the engaging portion 211a through the inspection hole 461h1. As a result, the gripping device 1 according to this embodiment makes it easy to position the conversion portion 4 in the correct position relative to the drive portion 2 in directions perpendicular to the axis 211z (i.e., in the X-axis direction and the Y-axis direction).

[0063] The gripping device 1 according to this embodiment has the following configuration. The shaft 43 has a shaft body portion 431 and an adhesive groove 433 formed in the shaft body portion 431 that is recessed radially inward, and the shaft 43 is fixed to the block 44 by adhesive filled in the adhesive groove 433. Therefore, the work of fixing the shaft 43 to the block 44 can be made easier.

[0064] The gripping device 1 according to this embodiment has the following configuration. The gripping device 1 further includes a relay plate 3 interposed between the cam case 461a and the motor case 212, wherein the position on the relay plate 3 where the cam case 461a is attached and the position on the relay plate 3 where the motor case 212 is attached are different. Therefore, the gripping device 1 according to this embodiment allows for easy assembly of the cam case 461a to the motor case 212 using the relay plate 3.

[0065] In the embodiments described above, a gripping device 1 having two gripping parts 45 was explained. However, the gripping device 1 according to the present invention is not limited to this. For example, the gripping device 1 may have three gripping parts 45, or four or more gripping parts 45.

[0066] Furthermore, the guide portion 46 described in the above embodiment is composed of a cam case 461a and a guide rail 461b. However, the guide portion 46 according to the present invention is not limited to this. For example, the guide portion 46 may be formed by integrally configuring the cam case 461a and the guide rail 461b.

[0067] Furthermore, the present invention is not limited by the above embodiments. Configurations that appropriately combine the components of the above embodiments are also included in the present invention. Moreover, further effects and modifications can be easily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the above embodiments, and various modifications are possible. [Explanation of Symbols]

[0068] 1 Gripping device, 2 Drive unit, 211 Drive shaft, 211a Engaging part, 212 Motor case, 3 Intermediate plate, 4 Conversion part, 41 Cam, 411 Cam groove, 411f1 One end face, 411f2 Other end face, 42 Bearing, 42f1 End face (of bearing), 43 Shaft, 431 Shaft body, 432 Widening part, 433 Adhesion groove, 44 Block, 441 Recess, 45 Gripping part, 461 Base part, 461a Cam case, 461h1 Inspection hole (through hole)

Claims

1. It is equipped with a conversion unit that converts the rotational drive of the drive shaft into the linear motion of the gripping part, The conversion unit is A cam having a cam groove formed that is recessed from one end face toward the other end face, A bearing inserted into the cam groove, It has, The end face of the bearing is positioned on the other end face side in the extending direction of the drive shaft, spaced apart from the one end face. gripping device.

2. The conversion unit further comprises a shaft whose other end is inserted into the bearing, and a block into which one end of the shaft is inserted. The shaft has a widened portion that protrudes radially outward, The block has a recess formed in which the widened portion engages. The gripping device according to claim 1.

3. The drive shaft has an engagement portion formed at one end in the extending direction. The conversion unit has a base portion in which the engagement portion of the drive shaft is formed, and which has a through hole that is visible from one side in the extending direction. The gripping device according to claim 1 or 2.

4. The shaft comprises a shaft body and an adhesive groove recessed radially inward on the circumferential surface of the shaft body. The shaft is fixed to the block by the adhesive filling the aforementioned adhesive groove. The gripping device according to claim 2.

5. A cam case that houses the aforementioned cam, A motor case housing the motor on which the aforementioned drive shaft is provided, A relay plate interposed between the cam case and the motor case, Furthermore, In the aforementioned relay plate, the position where the cam case is attached and the position where the motor case is attached are different. A gripping device according to any one of claims 1 to 4.

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