Clamp device

Abstract

To provide a structure which reduces falling of a slide part to hold a workpiece properly in a clamp device which slides a slide part to press a workpiece to hold it.SOLUTION: A clamp device 1 includes a slide part 20, a slide groove, a biasing part 52, a first fluid cylinder 30, and a transmission part. The transmission part includes a first transmission part 61 and a second transmission part 71. The first transmission part 61 has a first surface 65 and is slid in a first direction by a biasing force or a first pressing force. The second transmission part 71 has a second surface 72 which contacts with the first surface 65 and is pressed through the second surface 72 by the first transmission part 61 to press the slide part 20 in the first direction and in a direction such that a space between a first restriction surface and a second restriction surface is reduced while keeping a state that the first surface 65 is in contact with the second surface 72.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a clamping device for holding a workpiece, which is an object to be worked on. [Background technology]

[0002] Claim 1 of Patent Document 1 describes a clamping element that brings clamp jaws (8, 28, 35, 36) close to the workpiece (15) to hold the workpiece. The clamping element includes a driving element (4, 23, 33) driven by a cylinder or a ball screw, etc., and a slider (7, 9, 26) that slides with the driving element. A key taper (11, 39) is formed in the driving element, and a key element (10, 27, 38) is provided between the driving element and the slider. Since the key taper and the key element have a wedge structure, the keystone and the slider are pressed upward by the driving element. As a result, even if hydraulic pressure is no longer supplied to the cylinder, the slider is fixed and the workpiece can continue to be held. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] European Patent Application Publication No. 1277547 Summary of the Invention [Problem to be solved by the invention]

[0004] The clamping device of Patent Document 1 and the like has the following problems. That is, in a structure in which a slide part slides along a slide groove to hold a workpiece, ideally, the outside size of the slide part and the inside size of the slide groove should match. However, since there is variation in the size of the parts actually manufactured, the reference dimensions and dimensional tolerances are set taking into consideration the variation. As a result, a gap is present between the slide part and the slide groove. This gap may cause the slide part to slightly tilt during sliding (the posture of the slide part may change slightly). As a result, when the slide part in a slightly tilted state comes into contact with the workpiece and presses the workpiece, the workpiece is not pressed in the correct direction, and the workpiece may lift up, changing the position of the workpiece relative to the clamping device, and the workpiece may not be held properly.

[0005] The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a clamping device that slides a slide part to press and hold a workpiece, and has a configuration that can reduce the inclination of the slide part and properly hold the workpiece.

[0006] The problem to be solved by the present invention has been described above. Next, the means for solving this problem and the effects thereof will be described.

[0007] According to an aspect of the present invention, a clamping device having the following configuration is provided. That is, the clamping device holds a workpiece, which is a work object. The clamping device includes a slide portion, a slide groove, a biasing portion, an actuator, and a transmission portion. The slide portion is slidable in a first direction approaching a surface of the workpiece to be held and in a second direction opposite thereto. At least a part of the slide portion is inserted into the slide groove. The biasing portion generates a biasing force. The actuator generates a first pressing force for holding the workpiece. The transmission portion is capable of transmitting the biasing force and the first pressing force, and slides the slide portion by transmitting at least the first pressing force. The slide portion has a first restricting surface. The slide groove has a second restricting surface facing the first restricting surface. The transmission portion includes a first transmission portion and a second transmission portion. The first transmission portion has a first surface, and slides in the first direction by the biasing force or the first pressing force. The second transmission part has a second surface that contacts the first surface, and by being pressed by the first transmission part through the second surface, the second transmission part presses the slide part in the first direction and in a direction that reduces the gap between the first regulating surface and the second regulating surface while maintaining the contact state between the first surface and the second surface.

[0008] With this, when the workpiece is held by the first pressing force of the actuator, the sliding portion is pressed by the biasing force, so that the gap between the first restricting surface of the sliding portion and the second restricting surface of the slide groove can be reduced. As a result, the sliding portion can be prevented from falling over, so that the workpiece can be held appropriately.

[0009] The clamp device is preferably configured as follows: the actuator is a first fluid cylinder that generates the first pressing force by supplying a fluid, and a second fluid cylinder that generates a second pressing force for sliding the slide portion in the second direction is provided on the opposite side of the first fluid cylinder with the transmission portion in between.

[0010] Since it is difficult to finely adjust the pressing force of a fluid cylinder, the above-mentioned problems are likely to occur. Therefore, by applying the present invention, the above-mentioned effects can be effectively utilized.

[0011] The clamp device is preferably configured as follows: the first fluid cylinder includes a first fluid chamber to which fluid is supplied; the biasing portion is disposed in an arrangement space; and a third piston is provided to separate the first fluid chamber from the arrangement space and to be slidable in the first direction and the second direction.

[0012] This makes it possible to form a space for arranging the biasing portion in. Furthermore, since the third piston is slidable, when the first pressing force is generated, it is possible to press the transmission portion via the biasing portion.

[0013] In the clamp device, it is preferable that the third piston moves in the first direction when fluid is supplied to the first fluid chamber, and presses the transmission portion without using the biasing portion.

[0014] This allows the first pressing force generated by the fluid cylinder to be transmitted to the transmission part also via a path that does not pass through the biasing part.

[0015] The clamp device is preferably configured as follows: the first transmission part is formed with a first lubricant passage through which the lubricant to be supplied to the sliding part passes; the second transmission part is formed with a second lubricant passage through which the lubricant to be supplied to the sliding part passes; and the first lubricant passage and the second lubricant passage are connected to each other.

[0016] As a result, the lubricant flow path is formed in the transmission part, which makes it more compact than a configuration in which a dedicated space is provided to form the lubricant flow path. Also, since the first transmission part and the second transmission part are in contact with each other, the first lubricant flow path and the second lubricant flow path can be connected without any gaps.

[0017] The clamp device is preferably configured as follows. That is, the actuator is switchable between a first state in which the first pressing force is generated and a second state in which a force weaker than the first pressing force is generated or no force is generated. When the biasing force generated by the biasing portion is applied to the transmission portion, the actuator switches from the second state to the first state.

[0018] This allows the slide to be slid with a strong force applied while preventing the slide portion from falling over.

[0019] In the clamp device, it is preferable that the first surface includes an inclined surface and the second surface also includes an inclined surface, and that the inclination angles of the two inclined surfaces are equal.

[0020] This allows the force transmitted to the first transmission part to be transmitted efficiently to the second transmission part. [Brief description of the drawings]

[0021] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] Cross section AA of Figure 1. [Figure 4] FIG. 4 is a cross-sectional view of the clamp device in an open state. [Diagram 5] FIG. 4 is a cross-sectional view of the clamping device in a transition state. [Figure 6] 13 is an enlarged cross-sectional view showing the positional relationship between the transmission part and the slide part when changing from the open state to the transition state. FIG. [Figure 7] 13 is a side view showing the positional relationship between the slide portion and the slide groove when changing from the open state to the transition state. FIG. [Figure 8] FIG. 4 is a cross-sectional view of the clamp device in a holding state. [Figure 9] FIG. 13 is a cross-sectional view of a clamp device according to a modified example in an open state. [Figure 10] FIG. 13 is a cross-sectional view of a clamp device according to a modified example in a transition state. [Figure 11] FIG. 13 is a cross-sectional view of a clamp device according to a modified example in a holding state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Next, an embodiment of the present invention will be described with reference to the drawings. First, the configuration of a clamping device 1 will be described with reference to Figs.

[0023] The clamping device 1 is a device that holds a workpiece 100, which is an object to be worked on. The clamping device 1 is used, for example, to hold the workpiece 100 on the workbench of a machine tool. The clamping device 1 may be configured to hold the workpiece 100 by pressing the outer surface of the workpiece 100, or may be configured to hold the workpiece 100 by pressing the inner surface of the workpiece 100 (for example, the inner wall surface of a cylindrical workpiece 100). The clamping device 1 may be configured to hold the workpiece 100 by pressing one surface of the workpiece 100 against another location, or may be configured to hold the workpiece 100 by pressing multiple surfaces of the workpiece 100 and sandwiching it. The clamping device 1 can also be used to hold the workpiece 100 on the workbench of a machine other than a machine tool (for example, a machine that performs painting or cleaning, etc.). The clamping device 1 may also be provided at the tip of a robot arm.

[0024] As shown in Fig. 1, the clamp device 1 includes a casing 10 and a sliding part 20. Various components, which will be described later, are housed inside the casing 10. The sliding part 20 is a member that can slide relative to the casing 10. By sliding the sliding part 20, the sliding part 20 presses against the workpiece 100, and the workpiece 100 is held.

[0025] As shown in FIG. 2, the casing 10 is formed with a slide groove 11. The slide groove 11 is in an inverted T shape in side view (specifically, when viewed along the sliding direction). In detail, the slide groove 11 includes an upper groove 12 and a lower groove 13 located below the upper groove 12. The width of the upper groove 12 is smaller than the width of the lower groove 13. Therefore, the upper groove 12 can be called a narrow groove, and the lower groove 13 can be called a wide groove. In the description of the slide groove 11 and the sliding portion 20, the "width" refers to the length along the horizontal direction and the length in the direction perpendicular to the sliding direction. Of the inner surfaces of the slide groove 11, a surface located in the lower groove 13 and facing downward is referred to as a second restriction surface 14. Also, of the inner surfaces of the slide groove 11, a portion corresponding to the lower surface of the lower groove 13 is referred to as a bottom surface 15.

[0026] As shown in FIG. 2, the slide portion 20 is inverted T-shaped like the slide groove 11. In detail, the slide portion 20 includes a main body portion 21 and a leg portion 22. The width of the main body portion 21 is smaller than the width of the leg portion 22. A part of the main body portion 21 is inserted into the upper groove 12, and the leg portion 22 is inserted into the lower groove 13. The entire main body portion 21 may be inserted into the upper groove 12. The width and height of the leg portion 22 are approximately the same as the width and height of the lower groove 13, respectively. Moreover, the surface of the leg portion 22 facing upward is referred to as a first restriction surface 23.

[0027] The first restricting surface 23 and the second restricting surface 14 face each other. "Facing" means that the two surfaces face each other, and it does not matter whether they are in contact or not. The two opposing surfaces may be parallel or not. The existence of the first restricting surface 23 and the second restricting surface 14 restricts the slide portion 20 from moving excessively upward relative to the slide groove 11. As a result, the slide portion 20 can slide along a substantially horizontal direction. Hereinafter, among the sliding directions of the slide portion 20, the direction in which the slide portion 20 is brought close to the workpiece 100 (more specifically, the surface of the workpiece 100 that is pressed, the holding target surface 101 described later) is referred to as a first direction, and the direction in which the slide portion 20 is moved away from the workpiece 100 (i.e., the opposite direction to the first direction) is referred to as a second direction. In this embodiment, the up-down direction is defined as shown in FIG. 2, but this is an example. That is, even if the clamp device 1 is used in a direction different from that shown in FIG. 2, the clamp device 1 can achieve the effect described later. Therefore, for example, the “upward direction” may be rephrased as the “third direction,” and the “downward direction” may be rephrased as the “fourth direction.” The third direction and the fourth direction are opposite to and parallel to each other.

[0028] A lubricant is supplied to the slide structure formed by the slide groove 11 and the slide portion 20. The lubricant is, for example, grease or lubricating oil. A lubricant groove 24 for holding the supplied lubricant is formed in the slide portion 20. The lubricant supplied to the slide portion 20 is supplied to the boundary portion between the slide groove 11 and the slide portion 20, etc., via the lubricant groove 24 or another flow path.

[0029] As shown in FIG. 3, the casing 10 is provided with a first fluid cylinder (actuator) 30. The first fluid cylinder 30 generates a first pressing force by being supplied with a fluid. The first pressing force is a force generated by the first fluid cylinder 30 to hold the workpiece 100. In this embodiment, hydraulic oil is used as the fluid supplied to the first fluid cylinder 30, but a liquid or gas other than hydraulic oil may be used. In addition, other actuators may be used instead of the first fluid cylinder 30. The other actuators may be linear motion type actuators such as linear motors or solenoids. Alternatively, a configuration in which a rotary motion type actuator and a mechanical element that converts rotary motion into linear motion are combined may be used as the other actuator.

[0030] The first fluid cylinder 30 includes a first cylinder tube 31, a cover portion 32, and a first piston 33. The first cylinder tube 31 is a cylindrical member, and one end in the axial direction is sealed by the cover portion 32. As a result, a first fluid chamber 35 is formed as shown in FIG. 5 described later. In addition, hydraulic oil is supplied to the first fluid chamber 35 through a first hydraulic oil flow path 36, so that the first piston 33 moves in a first direction. As a result, the slide portion 20 slides by a mechanism described later, and the workpiece 100 is held. In addition, a state in which the first fluid cylinder 30 generates a first pressing force is referred to as a first state, and other states are referred to as a second state. In addition, the supply or discharge of hydraulic oil through the first hydraulic oil flow path 36 is performed using a pump (not shown). This pump operates according to an operator's instruction or program control.

[0031] The casing 10 is further provided with a second fluid cylinder 40. The description of the first fluid cylinder 30 also applies to the second fluid cylinder 40. When fluid is supplied to the second fluid cylinder 40, the second fluid cylinder 40 generates a second pressing force for sliding the sliding portion 20 in a second direction.

[0032] The second fluid cylinder 40 includes a second cylinder tube 41 and a second piston 43. The second cylinder tube 41 is a cylindrical member, and a second fluid chamber 45 is formed therein. The second piston 43 moves in the second direction by supplying hydraulic oil to the second fluid chamber 45 through a second hydraulic oil flow path 46. The second fluid cylinder 40 is a component for moving the slide portion 20, which has moved in the first direction, in the second direction and returning it to its original position. Therefore, if the slide portion 20 can be moved in the second direction by another means (spring, manual, or actuator), the second fluid cylinder 40 can be omitted. In addition, when a spring is used instead of the second fluid cylinder 40, it is necessary to select a spring having a larger spring constant than the biasing portion 52. In this case, the second fluid chamber 45 is used as a spring chamber.

[0033] A transmission unit 51 is provided between the first fluid cylinder 30 and the second fluid cylinder 40. The transmission unit 51 moves in a first direction (or a second direction) when pressed by a first pressing force (or a second pressing force), and slides the sliding unit 20 in the first direction (or the second direction). In other words, the transmission unit 51 transmits the force received from the first fluid cylinder 30 or the second fluid cylinder 40 to the sliding unit 20. A detailed configuration of the transmission unit 51 will be described later.

[0034] The biasing portion 52 is provided on the second direction side of the transmission portion 51. The biasing portion 52 generates a biasing force. In this embodiment, the biasing portion 52 is a spring (compression spring). However, the biasing portion 52 is not limited to a spring, and may be another elastic member such as rubber. The biasing portion 52 presses the transmission portion 51 in the first direction by the biasing force. The biasing force generated by the biasing portion 52 depends on the amount of compression of the spring. In this embodiment, the spring constant of the biasing portion 52 and the stroke of the first fluid cylinder 30 are designed so that the biasing force is weaker than the first pressing force. Moreover, the biasing portion 52 is arranged in the arrangement space 53.

[0035] The first fluid chamber 35 and the arrangement space 53 are partitioned by the third piston 54. The third piston 54 receives a reaction force of the biasing force applied to the transmission part 51 by the biasing part 52. The third piston 54 is also capable of moving in the first direction and the second direction in the space inside the first cylinder tube 31. In other words, the third piston 54 is a type of piston that moves by the first pressing force generated by the first fluid cylinder 30, and also has a function of partitioning the first fluid chamber 35 and the arrangement space 53. The first piston 33 and the third piston 54 are capable of relative movement.

[0036] Next, a detailed description will be given of the configuration of the transmission unit 51. The transmission unit 51 includes a first transmission unit 61 and a second transmission unit 71.

[0037] The first transmission part 61 is a part that receives the first pressing force and the second pressing force. In this embodiment, the first transmission part 61 and the first piston 33 are integrated, but may be separate. The first transmission part 61 has a first pressed surface 62 and a biased surface 63 as a part of the end face on the second direction side. The first pressed surface 62 is a surface that receives the first pressing force via the third piston 54. The biased surface 63 is a surface that receives a biasing force from the biasing part 52. The first transmission part 61 has a second pressed surface 64 as a part of the end face on the first direction side. The second pressed surface 64 is a surface that receives a second pressing force from the second piston 43. The first transmission part 61 also has a first surface 65 that faces upward. The first surface 65 contacts the second transmission part 71.

[0038] The second transmission part 71 has a second surface 72 facing downward. The first surface 65 and the second surface 72 are in contact with each other. In this embodiment, the first surface 65 and the second transmission part 71 are inclined surfaces that approach the downward direction as they approach the first direction. As a result, the second transmission part 71 is pressed in the first direction and upward by receiving the first pressing force from the first transmission part 61. In this embodiment, the inclination angles of the two inclined surfaces are equal, so the two inclined surfaces are in surface contact with each other. Therefore, the contact area is large, so that the force can be efficiently transmitted from the first transmission part 61 to the second transmission part 71. Note that the first surface 65 and the second transmission part 71 are not limited to inclined surfaces and may be curved surfaces.

[0039] Moreover, the second transmission part 71 has a pressing part 73. The pressing part 73 is a part that is assembled to the sliding part 20. In this embodiment, the pressing part 73 is a convex part, and is assembled to a concave part of the sliding part 20. However, the pressing part 73 may be a concave part and the sliding part 20 may be a convex part. The pressing part 73 receives a first pressing force (or a second pressing force) and slides the sliding part 20 in the first direction (or the second direction).

[0040] Further, a first lubricant passage 66 is formed in the first transmission part 61. A second lubricant passage 74 is formed in the second transmission part 71. The first lubricant passage 66 and the second lubricant passage 74 are passages for supplying lubricant to the sliding part 20. The first lubricant passage 66 and the second lubricant passage 74 are connected to each other. In detail, the first lubricant passage 66 and the second lubricant passage 74 are connected to each other at the contact point between the first surface 65 and the second surface 72.

[0041] Further, each part of the clamp device 1 is provided with a sealing member to prevent leakage of hydraulic oil or intrusion of dust, etc. The sealing member is made of, for example, rubber, but may be made of other materials. Hereinafter, sealing members are provided, for example, between the first cylinder tube 31 and the cover part 32, between the first cylinder tube 31 and the third piston 54, between the third piston 54 and the first piston 33, between the second cylinder tube 41 and the second piston 43, between the slide part 20 and the casing 10 (the first cylinder tube 31, the second cylinder tube 41), etc.

[0042] Next, the operation of the clamping device 1 to hold the workpiece 100 will be described with reference to FIGS.

[0043] As shown in Fig. 4 etc., the workpiece 100 is set on the worktable 102. By pressing the holding target surface 101 of the workpiece 100 using the clamp device 1, the workpiece 100 is pressed against the worktable 102 and the workpiece 100 is held. In the following description, a state in which the slide part 20 is not in contact with the workpiece 100 (holding target surface 101) and the workpiece 100 is not held is referred to as an "open state", a state in which the workpiece 100 is held is referred to as a "held state", and a state between these two in which the slide part 20 is in contact with the workpiece 100 is referred to as a "transition state".

[0044] In the open state shown in FIG. 4, hydraulic oil is supplied to the second fluid chamber 45. Due to the second pressing force generated by this, the sliding portion 20 is located at the end of the sliding range in the second direction. The sliding range is determined by the second transmission portion 71 and the slide holes formed in the first cylinder tube 31 and the second cylinder tube 41. The biasing portion 52 is in a contracted state due to the second pressing force. The biasing force of the biasing portion 52 is not large enough to overcome the second pressing force in the open state, so the sliding portion 20 does not slide in the first direction.

[0045] In the transition state shown in FIG. 5, hydraulic oil is discharged from the second fluid chamber 45 through the second hydraulic oil flow path 46 to a hydraulic oil tank (not shown). The second pressing force decreases as hydraulic oil is discharged from the second fluid chamber 45. At this point, since sufficient hydraulic oil is not supplied to the first fluid chamber 35, the first fluid cylinder 30 is in the second state and the first pressing force is not generated. Therefore, the first transmission part 61 moves in the first direction due to the biasing force generated by the biasing part 52. As a result, the second piston 43 is pressed by the first transmission part 61 and moves in the first direction. Since hydraulic oil is not supplied to the first fluid chamber 35, the third piston 54 does not move in the first direction. In addition, the second transmission part 71 receives forces in the first direction and upward direction. Due to the force in the first direction, the second transmission part 71 presses the slide part 20 in the first direction via the pressing part 73. As a result, the first transmitting part 61, the second transmitting part 71, and the sliding part 20 move in the first direction. In addition, the second transmitting part 71 receives an upward force from the first transmitting part 61 due to a biasing force.

[0046] Hereinafter, the advantage of the second transmission part 71 receiving the upward force by the biasing force will be described. As described in the problem, there is a gap between the first regulating surface 23 of the slide part 20 and the second regulating surface 14 of the slide groove 11. In this embodiment, as shown in the open state of FIG. 7, there is a gap between the first regulating surface 23 and the second regulating surface 14 when the slide part 20 is in contact with the bottom surface 15. As a result, when the slide part 20 is pressed with a strong force, the slide part 20 slightly falls during sliding. As a result, the slide part 20 in a slightly fallen state comes into contact with the holding target surface 101, and the slide part 20 follows the holding target surface 101 to eliminate the fall. When the slide part 20 is eliminated from the fall, the slide part 20 slightly lifts the workpiece 100, and the position of the workpiece 100 relative to the clamping device 1 changes, so that the workpiece 100 is not held in an appropriate position. Furthermore, if the machining of the workpiece 100 proceeds in this state, the machining accuracy of the workpiece 100 will vary. In this embodiment, the first regulating surface 23 and the second regulating surface 14 are spaced apart in the vertical direction, but as described above, the vertical direction is just an example, and the first regulating surface 23 and the second regulating surface 14 may be spaced apart in a direction other than vertical. Even in this case, the slide portion 20 will fall due to the gap between the first regulating surface 23 and the second regulating surface 14, and as a result, the position of the workpiece 100 relative to the clamping device 1 will change. In other words, the same problem will exist regardless of the direction in which the gap exists.

[0047] In this regard, in this embodiment, before the first pressing force is applied, the first transmission part 61 is pressed using a biasing force. As described above, the biasing force is weaker than the first pressing force, so the workpiece 100 is not held in the transition state. The second transmission part 71 receives an upward force due to the biasing force, and as shown in FIG. 6, the gap between the second transmission part 71 and the sliding part 20 disappears. As a result, the second transmission part 71 and the sliding part 20 come into contact with each other.

[0048] As a result, the slide portion 20 is pressed upward by the second transmission portion 71. As a result, as shown in FIG. 7, the gap between the first regulating surface 23 and the second regulating surface 14 disappears, and the first regulating surface 23 and the second regulating surface 14 are maintained in contact with each other. Therefore, thereafter, the slide portion 20 does not fall over during sliding. In other words, by applying the first pressing force in this state, the slide portion 20 presses the workpiece 100 horizontally, and thus no change in the position of the workpiece 100 with respect to the clamping device 1 described above occurs.

[0049] Specifically, as shown in FIG. 8, hydraulic oil is supplied to the first fluid chamber 35. This causes the first fluid cylinder 30 to generate a first pressing force (the first fluid cylinder 30 transitions from the second state to the first state). The first pressing force causes the third piston 54 to press the urging portion 52 in the first direction, causing the urging portion 52 to contract. This causes the third piston 54 to come into contact with the first transmission portion 61. Thereafter, the third piston 54 further presses the first transmission portion 61 in the first direction. The first transmission portion 61 presses the second transmission portion 71 via the first surface 65 and the second surface 72. As a result, the first pressing force is transmitted to the slide portion 20 via the first transmission portion 61 and the second transmission portion 71, and as a result, the slide portion 20 presses the workpiece 100 with a strong force, so that the workpiece 100 is held (held state). Furthermore, when the first pressing force is generated, the first regulating surface 23 and the second regulating surface 14 are maintained in contact with each other as described above, so the slide portion 20 does not fall over. Therefore, the slide portion 20 can press the workpiece 100 horizontally, so that the workpiece 100 can be held in an appropriate position.

[0050] In addition, when the first surface 65 and the second surface 72 are inclined surfaces, the angle formed by the first surface 65 or the second surface 72 with respect to the horizontal direction is set to an angle θ as shown in FIG. 5. The larger the angle θ, the stronger the force with which the slide portion 20 presses the workpiece 100, and the stronger the holding force of the workpiece 100. In addition, the smaller the angle θ, the stronger the frictional force between the first transmission portion 61 and the second transmission portion 71, so that the workpiece 100 becomes difficult to move when an external force is applied to the workpiece 100. On the other hand, if the angle θ is too large, the upward force received by the slide portion 20 becomes smaller, so that a gap may occur between the first regulating surface 23 and the second regulating surface 14. In consideration of the above, the angle θ is preferably 12° or more and 35° or less, and more preferably 18° or more and 22° or less.

[0051] Next, a modified example of the above embodiment will be described with reference to Figures 9 to 11. In the description of this modified example, the same or similar members as those in the above embodiment are denoted by the same reference numerals in the drawings, and the description thereof may be omitted.

[0052] In the above embodiment, one slide portion 20 presses the workpiece 100, thereby pressing and holding the workpiece 100 against the work table 102. In contrast, in this modified example, two slide portions 20 press the workpiece 100 in a sandwiched manner, thereby holding the workpiece 100.

[0053] As shown in FIG. 9, the clamp device 1 of the modified example includes a first clamp structure 1a and a second clamp structure 1b. The first clamp structure 1a has exactly the same configuration as the clamp device 1 of the above embodiment. The second clamp structure 1b is symmetrical with respect to the boundary line between the first clamp structure 1a and the second clamp structure 1b. The points described about the clamp device 1 in the above embodiment can be applied to the first clamp structure 1a and the second clamp structure 1b. Therefore, detailed explanation of the structures of the first clamp structure 1a and the second clamp structure 1b will be omitted.

[0054] In the clamp device 1 of this modification, hydraulic oil is controlled simultaneously to synchronize the operations of the first clamp structure 1a and the second clamp structure 1b. Specifically, the clamp device 1 includes one pump. The pump supplies hydraulic oil to a first flow path for operating the first clamp structure 1a and a second flow path for operating the second clamp structure 1b. In addition, a switching valve is provided in each of the first flow path and the second flow path. In this modification, by simultaneously sending commands to these two switching valves, the supply of hydraulic oil to the first flow path and the second flow path is performed at the same time, and the discharge of hydraulic oil from the first flow path and the second flow path is performed at the same time.

[0055] In addition, the biasing force of the biasing portion 52 in this modification is smaller than the frictional force due to the weight of the workpiece 100. Therefore, even if one of the sliding portions 20 contacts the workpiece 100 first in the transition state of Fig. 10, the workpiece 100 does not slide. Therefore, even if only one of the sliding portions 20 starts to slide first due to a difference in the timing of discharging the hydraulic oil from the second fluid chamber 45, the workpiece 100 does not fall off the workbench.

[0056] In this modified example, both the first clamp structure 1a and the second clamp structure 1b have the same configuration as the clamp device 1 of the above embodiment, but only one of the first clamp structure 1a and the second clamp structure 1b may have the same configuration as the clamp device 1.

[0057] As described above, the clamp device 1 of this embodiment or the modified example includes the slide portion 20, the slide groove 11, the biasing portion 52, the first fluid cylinder 30, and the transmission portion 51. The slide portion 20 is slidable in a first direction approaching the holding target surface 101 of the workpiece 100 and in a second direction opposite thereto. At least a part of the slide portion 20 is inserted into the slide groove 11. The biasing portion 52 generates a biasing force. The first fluid cylinder 30 generates a first pressing force for holding the workpiece 100. The transmission portion 51 is capable of transmitting the biasing force and the first pressing force, and slides the slide portion 20 by transmitting at least the first pressing force. The slide portion 20 has a first restricting surface 23. The slide groove 11 has a second restricting surface 14 facing the first restricting surface 23. The transmission portion 51 includes a first transmitting portion 61 and a second transmitting portion 71. The first transmission part 61 has a first surface 65, and slides in a first direction due to a biasing force or a first pressing force. The second transmission part 71 has a second surface 72 that contacts the first surface 65, and is pressed by the first transmission part 61 via the second surface 72, thereby pressing the sliding part 20 in the first direction and in a direction in which the gap between the first restriction surface 23 and the second restriction surface 14 becomes smaller (third direction) while maintaining the state in which the first surface 65 and the second surface 72 are in contact with each other.

[0058] As a result, when the workpiece 100 is held by the first pressing force of the first fluid cylinder 30, the sliding portion 20 is pressed by the biasing force, thereby making it possible to reduce the gap between the first restricting surface 23 of the sliding portion 20 and the second restricting surface 14 of the slide groove 11. As a result, the inclination of the sliding portion 20 can be reduced, so that the workpiece 100 can be held appropriately.

[0059] In the clamp device 1 of this embodiment or the modified example, the first fluid cylinder 30 is a first fluid cylinder that generates a first pressing force by supplying a fluid. On the opposite side of the first fluid cylinder 30 across the transmission part 51, a second fluid cylinder 40 that generates a second pressing force for sliding the sliding part 20 in a second direction is provided.

[0060] Since it is difficult to finely adjust the pressing force of a fluid cylinder, the above-mentioned problems are likely to occur. Therefore, by applying the present invention, the above-mentioned effects can be effectively utilized.

[0061] In the clamp device 1 of this embodiment or the modified example, the first fluid cylinder 30 includes a first fluid chamber 35 to which a fluid is supplied. The biasing portion 52 is disposed in the arrangement space 53. A third piston 54 is provided to separate the first fluid chamber 35 from the arrangement space 53 and to be slidable in a first direction and a second direction.

[0062] This makes it possible to form an arrangement space 53 for arranging the urging portion 52. In addition, since the third piston 54 is slidable, it is possible to press the transmission portion 51 via the urging portion 52 when the first pressing force is generated.

[0063] In the clamp device 1 of this embodiment or the modified example, the third piston 54 moves in the first direction when fluid is supplied to the first fluid chamber 35, and presses the transmission portion 51 without the biasing portion 52 being involved.

[0064] This allows the first pressing force generated by the first fluid cylinder 30 to be transmitted to the transmitting portion 51 even through a flow path that does not pass through the biasing portion 52.

[0065] In the clamp device 1 of this embodiment or the modified example, the first transmission part 61 is formed with a first lubricant passage 66 through which the lubricant to be supplied to the sliding part 20 passes. The second transmission part 71 is formed with a second lubricant passage 74 through which the lubricant to be supplied to the sliding part 20 passes. The first lubricant passage 66 and the second lubricant passage 74 are connected.

[0066] As a result, a lubricant flow path is formed in the transmission part 51, which is more compact than a configuration in which a lubricant flow path is formed by providing a dedicated space. In addition, since the first transmission part 61 and the second transmission part 71 are in contact with each other, the first lubricant flow path 66 and the second lubricant flow path 74 can be connected without any gaps.

[0067] In the clamp device 1 of this embodiment or the modified example, the first fluid cylinder 30 is switchable between a first state in which a first pressing force is generated and a first fluid cylinder 30 in which a first fluid cylinder 30 that is weaker than the first pressing force is generated or a first fluid cylinder 30 that is not generated. In a state in which the biasing force generated by the biasing unit 52 is applied to the transmission unit 51, the first fluid cylinder 30 is switched from the first fluid cylinder 30 to the first state.

[0068] This allows the slide to be slid with a strong force applied while preventing the slide portion from falling over.

[0069] In the clamp device 1 of this embodiment or the modified example, the first surface 65 includes an inclined surface, and the second surface 72 also includes an inclined surface, and the inclination angles of the two inclined surfaces are equal.

[0070] This allows the force transmitted to the first transmission part 61 to be transmitted to the second transmission part 71 efficiently.

[0071] Although the preferred embodiment of the present invention has been described above, the above configuration can be modified, for example, as follows.

[0072] In the above embodiment, the sliding portion 20 slides due to the biasing force of the biasing portion 52, but for example, in cases where the frictional force for sliding the sliding portion is large, the sliding portion 20 does not have to slide. Even in this case, the sliding portion 20 moves upward, so that the gap between the second restriction surface 14 and the first restriction surface 23 can be made small.

[0073] In the above embodiment, the slide groove 11 and the slide portion 20 are inverted T-shaped, but may have other shapes as long as the second restriction surface 14 and the first restriction surface 23 are formed.

[0074] In addition to the above-mentioned configuration, parts for power transmission or position adjustment may be provided. Alternatively, parts that are not essential for achieving the effects of the present invention may be omitted. Furthermore, at least one of the above-mentioned parts may be divided into multiple parts, or any two of the above-mentioned parts may be integrated. [Explanation of symbols]

[0075] 1 Clamping device 11 Slide groove 14 Second Regulatory Plane 20 Slide section 23 First Regulatory Plane 30 First fluid cylinder (actuator) 51 Transmission section 52 Pressurizing section 61 First Transmission Section 65 Page 1 71 Second Transmission Section 72 2nd page

Claims

1. In a clamping device for holding a workpiece, A slide portion that is slidable in a first direction approaching a holding target surface of the workpiece and in a second direction opposite thereto; a slide groove into which at least a portion of the slide portion is inserted; A biasing portion that generates a biasing force; an actuator that generates a first pressing force for holding the workpiece; a transmission unit capable of transmitting the biasing force and the first pressing force and causing the sliding unit to slide by transmitting at least the first pressing force; Equipped with The slide portion has a first restriction surface, The slide groove has a second restriction surface facing the first restriction surface, The transmission unit is a first transmission part having a first surface and sliding in the first direction by the biasing force or the first pressing force; a second transmission part having a second surface in contact with the first surface, and being pressed by the first transmission part via the second surface, the second transmission part pressing the slide part in the first direction and in a direction in which a gap between the first restriction surface and the second restriction surface becomes smaller while maintaining a state in which the first surface and the second surface are in contact; A clamping device comprising:

2. 2. The clamping device of claim 1, the actuator is a first fluid cylinder that generates the first pressing force by supplying a fluid thereto; A clamping device characterized in that a second fluid cylinder is provided on the opposite side of the transmission part from the first fluid cylinder, generating a second pressing force for sliding the slide part in the second direction.

3. 3. The clamping device according to claim 2, the first fluid cylinder includes a first fluid chamber to which a fluid is supplied; The biasing portion is disposed in the arrangement space, A clamp device comprising: a third piston that separates the first fluid chamber from the arrangement space and is slidable in the first direction and the second direction.

4. 4. The clamping device according to claim 3, A clamp device characterized in that the third piston moves in the first direction when fluid is supplied to the first fluid chamber, and presses the transmission portion without passing through the biasing portion.

5. 2. The clamping device of claim 1, a first lubricant flow path through which a lubricant to be supplied to the slide portion passes is formed in the first transmission portion; a second lubricant passage through which a lubricant to be supplied to the slide portion passes is formed in the second transmission portion; A clamp device, characterized in that the first lubricant passage and the second lubricant passage are connected to each other.

6. 2. The clamping device of claim 1, the actuator is switchable between a first state in which the first pressing force is generated and a second state in which a force weaker than the first pressing force is generated or no force is generated, A clamp device, characterized in that, in a state in which the biasing force generated by the biasing portion is applied to the transmission portion, the actuator switches from the second state to the first state.

7. 2. The clamping device of claim 1, A clamping device, characterized in that the first surface includes an inclined surface and the second surface also includes an inclined surface, the inclination angles of the two inclined surfaces being equal.

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