Clamping device

Abstract

To provide a clamp device in which a shaft center of a clamp rod is deviated from a shaft center of a piston, which can suppress a rotation load from acting on the clamp rod.SOLUTION: A clamp device is provided with a piston (8), a clamp rod (29) and a link member (49) arranged inside a housing (1). When a second end part (53) which is an end part at the other side of the link member (49) is pressed by a tip part of a piston rod (11), a first end part (51) of the link member (49) presses a shaft center (C2) part of the clamp rod (29) or a plurality of portions of the clamp rod (29) arranged at an equally-spaced position around the shaft center (C2) part, so that the clamp rod (29) is moved in a direction of a base end side of directions of the shaft centers.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a clamping device in which the axis of the clamping rod is displaced from the axis of the piston.

Background Art

[0002] As the above clamping device, there is one described in Patent Document 1 below. The clamping device is configured as follows.

[0003] The clamping device includes a connecting member that connects the input portion of the clamping rod and the output portion of the piston. A convex portion protruding in the radial direction is provided on the output portion of the piston. A concave portion that engages with the convex portion in the radial direction is provided on the connecting member. The connecting member is inserted into the housing so as to be movable together with the piston in the axial direction of the piston.

[0004] When the clamping device switches from the release state to the lock state, the connecting member is pulled down by the piston. In Patent Document 1, the connecting member is regarded as a member separate from the clamping rod, but the connecting member may be regarded as a part constituting the clamping rod.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The clamping device described above had room for improvement. Because the piston pulls downwards on the right side of the connecting member due to a protrusion on the piston's output, a rotational load may be applied from the piston to the connecting member. Therefore, in the worst-case scenario, for example, the lower left and upper right portions of the connecting member may come into strong contact with the inner surface of the cylindrical hole, potentially preventing the connecting member from moving smoothly. Furthermore, strong localized contact of the connecting member with the inner surface of the cylindrical hole could cause uneven wear on that surface. In this case, the connecting member may tilt and descend during the locking mechanism.

[0007] The object of the present invention is to provide a clamping device in which the axis of the clamping rod is offset from the axis of the piston, which can suppress the application of rotational loads to the clamping rod. [Means for solving the problem]

[0008] To achieve the above objective, the clamping device according to the present invention is configured as follows, for example, as shown in Figures 1 to 9.

[0009] (1) The clamping device disclosed herein comprises a housing 1, a piston 8 inserted into a cylinder bore 7 formed in the housing 1 so as to be movable in the axial direction of the cylinder bore 7, the piston 8 comprising a piston body 9 and a piston rod 11, a clamping rod 29 inserted into the housing 1 so as to be movable in the axial direction, the clamping rod 29 having an axis C2 that is separated from the axis C1 of the piston 8 in a direction perpendicular to the axial direction, and a link member 49 disposed inside the housing 1, the link member 49 which interlocks the clamping rod 29 and the piston rod 11. One end of the link member 49, the first end 51, is positioned on the clamping rod 29 side. When the second end 53, which is the other end of the link member 49, is pressed by the tip of the piston rod 11, the first end 51 presses the axis C2 of the clamp rod 29, or multiple portions of the clamp rod 29 that are equally spaced around the axis C2, causing the clamp rod 29 to move in the direction toward the base end of the axial direction.

[0010] The clamping device disclosed herein provides the following effects: Since the axial center of the clamping rod, or multiple portions of the clamping rod positioned equally around the axial center, are pressed by the link member, it is difficult for a load that would cause the clamping rod to rotate to occur. In other words, this clamping device can suppress the application of a rotational load to the clamping rod.

[0011] (2) In the clamping device of (1), for example, as shown in Figures 1 to 8, the first end 51 is inserted into a recess 52 formed on the side surface of the clamping rod 29, and the second end 53 is pushed by the tip of the piston rod 11, so that the first end 51 pushes the axis C2 portion of the clamping rod 29 in the recess 52 toward the base end, and the clamping rod 29 moves toward the base end.

[0012] This configuration makes it possible to suppress rotational loads from acting on the clamp rod.

[0013] (3) In the clamping device of (1), for example, as shown in Figure 9, the first end 51 is inserted into a recess 64 formed on the side surface of the clamp rod 29, and the second end 53 is pushed by the tip of the piston rod 11, so that the first end 51 pushes multiple portions of the clamp rod 29 that are equally spaced around the axis C2 of the clamp rod 29 in the recess 64 toward the base end, and the clamp rod 29 moves toward the base end.

[0014] In this configuration, multiple parts of the clamp rod are pressed by the link member, resulting in more stable movement of the clamp rod compared to when only one part of the clamp rod is pressed by the link member.

[0015] In the clamping device of (4)(3), for example, as shown in Figures 9A to 9C, the first end 51 has a bifurcated shape with a first-first end 65 and a first-second end 66, and a wall 67 that constitutes a part of the clamping rod 29 is provided between the first-first end 65 and the first-second end 66, passing through the axis C2 of the clamping rod 29.

[0016] This configuration allows the rigidity of the clamp rod to be increased by the wall, resulting in more stable movement of the clamp rod.

[0017] (5) In any of the clamping devices described in (1) to (4), the base end direction is the locking direction of the clamping rod 29, the piston rod 11 protrudes from the piston body 9 toward the tip direction in the axial direction, and as the piston rod 11 moves toward the tip direction, the clamping rod 29 may move toward the base end direction opposite to the tip direction via the link member 49.

[0018] According to this configuration, the piston output during the lock drive becomes larger than the piston output during the release drive. Therefore, in the lock drive, the clamp rod can be moved with a large force.

[0019] (6) In any of the clamp devices from (1) to (5), for example, as shown in FIGS. 1 and 2, the link member 49 is supported by a rotation support shaft 50, and the rotation support shaft 50 may be supported by the housing 1.

[0020] According to this configuration, the link member can be easily operated with a simple configuration without waste.

[0021] (7) In any of the clamp devices from (1) to (5), for example, as shown in FIGS. 4 and 5, the link member 49 is supported by a rotation support shaft 50, and the rotation support shaft 50 may be supported by the clamp rod 29.

[0022] According to this configuration, the link member can be easily operated.

[0023] (8) In any of the clamp devices from (1) to (5), for example, as shown in FIG. 6, the link member 49 is supported by a rotation support shaft 50, and the rotation support shaft 50 may be supported by the tip of the piston rod 11.

[0024] According to this configuration, the link member can be easily operated.

[0025] (9) In any one of the clamping devices (1) to (8), the clamping device may include a pressing member 35 disposed on the outer peripheral side of the tip of the clamping rod 29 so as to be inserted into the hole 32 of the object to be fixed W and to be in close contact with the inner peripheral surface of the hole 32; a support cylinder 34 disposed inside the housing 1 so as to push the pressing member 35 in the tip side direction of the axial direction, the support cylinder 34 having a cylindrical hole 34a into which the clamping rod 29 is inserted; and biasing means 45, 59 for biasing the support cylinder 34 in the tip side direction, the biasing means 45, 59 being disposed inside the housing 1.

[0026] According to this configuration, the configuration for fixing the object to be fixed to the housing by bringing the pressing member into close contact with the hole of the object to be fixed becomes compact.

[0027] (10) In the clamping device (9), for example, as shown in FIG. 3, the biasing means 59 may be a fluid pressure-driven support piston 59.

[0028] According to this configuration, the support cylinder can be easily biased in the tip side direction.

[0029] (11) In any one of the clamping devices (1) to (10), the link member 49 is disposed in a link chamber 48 formed inside the housing 1, and compressed air for air blowing may be supplied from an air supply passage 54 formed in the housing 1 to the link chamber 48.

[0030] According to this configuration, it is possible to further suppress the entry of dust or the like into the link chamber 48, and as a result, it is possible to prevent the link member from being worn or damaged by dust or the like.

[0031] (12) In any one of the clamping devices (1) to (11), the clamping rod 29 may have, in order from the tip side, a clamping rod body 30 and a connecting member 31.

Effects of the Invention

[0032] According to the present invention, it is possible to provide a clamping device in which the axis of the clamping rod is offset from the axis of the piston, thereby suppressing the application of rotational loads to the clamping rod. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 shows a first embodiment of the present invention, and is a cross-sectional view of the clamping device in the released state. [Figure 2] Figure 2 is a side view cross-sectional view of the clamping device shown in Figure 1 in the locked state. [Figure 3] Figure 3 shows a modified example of the first embodiment, and is a cross-sectional view of the clamping device in the released state. [Figure 4] Figure 4 shows a second embodiment of the present invention, and is a cross-sectional view of the clamping device in the released state. [Figure 5] Figure 5 is a side view cross-sectional view of the clamping device shown in Figure 4 in the locked state. [Figure 6] Figure 6 shows a third embodiment of the present invention, and is a cross-sectional view of the clamping device in the released state. [Figure 7] Figure 7 shows a modified example of the first embodiment, and is a cross-sectional view of the clamping device in the released state. [Figure 8] Figure 8 shows a modified example of the first embodiment, and is a cross-sectional view of the clamping device in the released state. [Figure 9A] Figure 9A is a side cross-sectional view showing modified versions of the link member and modified versions of the connecting member constituting the clamp rod. [Figure 9B] Figure 9B is a cross-sectional view of Figure 9A, taken along the line 9B-9B. [Figure 9C] Figure 9C is a cross-sectional view of Figure 9A, taken from the line 9C-9C. [Modes for carrying out the invention]

[0034] Figures 1 and 2 show a first embodiment of the present invention. First, the configuration of the clamping device of the first embodiment will be described based on Figures 1 and 2.

[0035] The housing 1 of the clamping device is fixed to a fixed base T such as a table. The housing 1 comprises a lower housing 2 as a first housing, an upper housing 3 as a second housing, and a lower end wall 4 fixed to the lower end of the lower housing 2. The lower housing 2 and the upper housing 3 are fixed together by a plurality of bolts (not shown).

[0036] A first cylinder hole 5 is formed in the lower part (base end portion) of the lower housing 2, and a second cylinder hole 6 is formed above the first cylinder hole 5 (tip end side). The first cylinder hole 5 and the second cylinder hole 6 constitute a cylinder hole 7.

[0037] A piston 8 is inserted into the cylinder bore 7 so as to be movable in the axial direction Z of the cylinder bore 7. The piston 8 is a fluid-pressure driven piston comprising a first piston body 9 as the piston body, a piston rod 11, and a second piston body 10.

[0038] The first piston body 9 is inserted into the first cylinder bore 5, which is the lower part of the cylinder bore 7, in a way that allows it to move vertically (in the axial direction Z of the cylinder bore 7) and in a sealed manner. A piston rod 11 is fixed to the first piston body 9 with bolts 12. The piston rod 11 is fixed to the first piston body 9 at its end and protrudes upward (towards the tip) in the axial direction Z mentioned above. The piston rod 11 does not protrude downward (towards the base) from the first piston body 9.

[0039] Furthermore, the first piston body 9 and the piston rod 11 may be integrated into a single unit. In other words, the first piston body 9 and the piston rod 11 may be formed from a single material.

[0040] The second piston body 10 is inserted into the second cylinder bore 6 at the upper (tip) side of the first piston body 9 in a tightly sealed manner, allowing it to move vertically (in the axial direction Z of the cylinder bore 7). The piston rod 11 is inserted tightly into this second piston body 10. The second piston body 10 is restricted from moving upward (towards the tip) by a stepped portion 11a formed on the outer circumference of the piston rod 11, and is configured to push the piston rod 11 toward the tip. The second piston body 10 may also be fixed to the piston rod 11.

[0041] The first cylinder bore 5 has a larger diameter than the second cylinder bore 6, and a stepped portion 13 is formed at the boundary between the first cylinder bore 5 and the second cylinder bore 6. A partition wall 14, which separates the cylinder bore 7 between the first cylinder bore 5 and the second cylinder bore 6, is inserted into this stepped portion 13 in a secure manner. The partition wall 14 is fixed to the lower housing 2 by the stepped portion 13 and a retaining ring 15. The piston rod 11 is inserted into an insertion hole formed in the partition wall 14 in a secure manner via a sealing member.

[0042] A first locking chamber 16 for moving the first piston body 9 upward (towards the tip) is provided between the lower end wall 4 and the first piston body 9 (below the first piston body 9 (towards the base end)), and a second locking chamber 17 for moving the second piston body 10 upward (towards the tip) is provided between the partition wall 14 and the second piston body 10. Compressed air, as a pressure fluid for locking, is supplied to and discharged from the first locking chamber 16 and the second locking chamber 17 via the locking port 18. The locking port 18 and the second locking chamber 17 are connected by a port-side passage 19 formed in the lower housing 2, and the second locking chamber 17 and the first locking chamber 16 are connected by a first locking passage 20 formed inside the piston rod 11 and a second locking passage 21 formed in the bolt 12. The port-side passage 19, the first locking passage 20, and the second locking passage 21 constitute a locking passage 22 for supplying and discharging pressurized fluid to the first locking chamber 16 and the second locking chamber 17. The first locking passage 20 has a hole 20a drilled radially inward from the outer circumferential surface of the piston rod 11 and a hole 20b extending axially along the piston rod 11. Note that the illustration of the compressed air supply and discharge passage to the lock port 18 is omitted.

[0043] The area of ​​the lower surface (pressure-receiving area) of the first piston body 9 is larger than the area of ​​the upper surface (pressure-receiving area) of the first piston body 9 by the cross-sectional integral of the piston rod 11. Therefore, the upward driving force of the piston rod 11 is greater than the downward driving force of the piston rod 11. The downward direction (towards the base end) is the locking direction of the clamp rod 29. As the piston rod 11 moves upward (towards the tip end), the clamp rod 29 moves via the link member 49 in the direction opposite to the tip end direction, i.e., the locking direction. As a result, the piston output during locking is greater than the piston output during release. Therefore, the clamp rod 29 can be moved with a large force during locking. Also, because the locking driving force is large, there is no need for a large piston 8, and a compact clamping device is possible.

[0044] The conventional clamping device described in Patent Document 1 locks the workpiece by the downward movement of a piston. In this embodiment, the upward driving force of the piston 8 (piston rod 11), which is greater than the downward driving force of the piston in the conventional clamping device, is reversed by the link member 49 and acts downward (locking direction) on the clamp rod 29. Therefore, with this embodiment, the locking driving force can be increased compared to the conventional clamping device, and as a result, the object to be fixed (workpiece W) can be clamped more strongly than in the conventional device with a piston of the same diameter.

[0045] A first spring 27 is positioned in the first locking chamber 16 as a first biasing means for biasing the first piston body 9 upward (towards the tip). The first spring 27 is a compression coil spring, and in this embodiment, two first springs 27 are positioned in the first locking chamber 16. A second spring 28 is positioned in the second locking chamber 17 as a second biasing means for biasing the second piston body 10 upward (towards the tip). The second spring 28 is a compression coil spring, and in this embodiment, two second springs 28 are positioned in the second locking chamber 17. The number of first springs 27 and second springs 28 is not limited to two. By providing the first springs 27 and second springs 28, the piston output during locking can be increased. Note that the first springs 27 and second springs 28 are optional.

[0046] A first release chamber 23 is provided between the first piston body 9 and the partition wall 14, and a second release chamber 24 is provided above (towards the tip) the second piston body 10. Compressed air, as the pressure fluid for release, is supplied to and discharged from the first release chamber 23 through a first release passage 25 formed in the lower housing 2. Similarly, compressed air, as the pressure fluid for release, is supplied to and discharged from the second release chamber 24 through a second release passage 26 formed in the lower housing 2. The release ports communicating with the first release passage 25 and the second release passage 26 are not shown in the illustration.

[0047] A clamp rod 29 is inserted into the upper housing 3 so as to be movable in the axial direction Z. The clamp rod 29 is locked by being moved downward (towards the base end) by the piston 8. The axis C2 of the clamp rod 29 is located a predetermined distance from the axis C1 of the piston 8 in a direction perpendicular to the axial direction Z. The axes C1 and C2 are parallel. The clamp rod 29 has, in order from the tip side, a clamp rod body 30 and a connecting member 31. The clamp rod body 30 and the connecting member 31 are arranged coaxially. A T-groove 31a is formed in the upper end portion of the connecting member 31, and a T-leg 30a provided at the lower end of the clamp rod body 30 engages with this T-groove 31a. The T-leg 30a (clamp rod body 30) and the connecting member 31 are connected by a pin member 36. The pin member 36 is optional. The clamp rod body 30 is connected to the connecting member 31 so as to be movable in the horizontal direction by the T-groove 31a and the T-leg 30a.

[0048] To ensure smooth movement of the connecting member 31, grooves 31b extending in the circumferential direction are formed on the side surface (outer surface) of the connecting member 31. Multiple grooves 31b are formed. By forming oil reservoirs in the grooves 31b, the frictional force acting between the cylindrical hole 34a of the support cylinder 34 (described later) and the side surface of the connecting member 31 can be reduced, thereby ensuring smooth movement of the connecting member 31.

[0049] A cylindrical (cap-shaped) cover member 33 is positioned on the outer circumference of the tip of the clamp rod body 30, and is inserted into a hole 32 in the workpiece W, which is the object to be fixed. A support cylinder 34 is positioned below the cover member 33. Multiple openings 33a are formed on the side surface of the cover member 33, and a gripper 35, which acts as a pressing member, is positioned inside each of these openings 33a. On the outer circumference of the gripper 35 (cover member 33), an annular seating surface 57 is formed on the upper surface of the upper housing 3 to receive the workpiece W. The gripper 35 functions as a gripping member to line the inner circumference of the hole 32. The gripper 35 is positioned on the outer circumference of the tip of the clamp rod body 30 in the above configuration. Note that the cover member 33 is optional. In this case, the support cylinder 34 would be positioned directly below the gripper 35.

[0050] In this embodiment, three grippers 35 are arranged at predetermined intervals in the circumferential direction. Each gripper 35 includes a contact portion 37 and a lower flange 38 at its tip. Multiple sawtooth-shaped protrusions 37a are formed on the outer circumference of the contact portion 37 in the vertical direction. An inclined surface 37b is formed on the inner circumference of the contact portion 37 so as it extends downward, it approaches the axis C2 of the clamp rod body 30.

[0051] A wedge-shaped surface (wedge portion) 30b that engages with the inclined surface 37b from above is formed at the tip of the clamp rod body 30. Three of these wedge-shaped surfaces 30b are provided, corresponding to the number of inclined surfaces 37b. In this embodiment, both the wedge-shaped surface 30b and the inclined surface 37b are made of flat surfaces.

[0052] Thin-walled rings 39 made of an elastic material such as rubber are fitted to the lower flanges 38 of the three grippers 35 and the lower part of the cover member 33. The elastic force of these rings 39 biases each gripper 35 radially inward toward the axis C2 of the clamp rod body 30.

[0053] A dust seal 40 is fitted to the peripheral wall of the upper hole 3a of the upper housing 3, preventing foreign matter from entering the housing 1 through the upper hole 3a. The elastic force of this dust seal 40 biases each gripper 35, cover member 33, and clamp rod 29 radially inward toward the axis of the upper hole 3a.

[0054] The support cylinder 34 comprises an upper wall 41 that supports each gripper 35 from below via a cover member 33, and an annular wall 42 that extends downward from the outer circumference of the upper wall 41. The inner circumferential surfaces of the upper wall 41 and the annular wall 42 form a cylindrical hole 34a of the support cylinder 34. A connecting member 31 constituting the clamp rod 29 is inserted into this cylindrical hole 34a. The support cylinder 34 is inserted into a housing hole 43 provided in the upper housing 3 so as to be vertically movable. Furthermore, a spring 45 is arranged in a spring chamber 44 formed inside the lower housing 2 below the support cylinder 34 as a biasing means for biasing the support cylinder 34 upward (towards the tip). The spring 45 is a compression coil spring. A disc-shaped spring receiver 46 is provided above the spring 45. The spring receiver 46 supports the lower end of the annular wall 42 of the support cylinder 34. This spring 45 biases the gripper 35 upward (towards the tip) via the spring receiver 46, support cylinder 34, and cover member 33.

[0055] To ensure smooth movement of the support cylinder 34, grooves 42a extending in the circumferential direction of the annular wall 42 are formed on the outer circumferential surface of the annular wall 42. Multiple grooves 42a are formed. By forming oil reservoirs in the grooves 42a, the frictional force acting between the inner circumferential surface of the housing hole 43 and the outer circumferential surface of the annular wall 42 can be reduced, thereby ensuring smooth movement of the support cylinder 34.

[0056] In addition to the spring 45, a release spring 47 is also located in the spring chamber 44. The release spring 47 is a compression coil spring. This release spring 47 biases the clamp rod 29 upward (towards the tip).

[0057] A link member 49 is positioned in a link chamber 48 formed inside the upper housing 3 above the piston rod 11, which interlocks the clamp rod 29 with the piston rod 11. The link member 49 is supported by a pivot shaft 50 and is rotatable about the axis of the pivot shaft 50. The pivot shaft 50 is fixed to the upper housing 3 at both ends. In other words, the pivot shaft 50 is supported by the upper housing 3. In this embodiment, the pivot shaft 50 is immovable and the link member 49 is rotatable relative to the pivot shaft 50, however, the pivot shaft 50 may be rotatable relative to the upper housing 3 and the link member 49 may be fixed to the pivot shaft 50.

[0058] Since the link member 49 is positioned inside the upper housing 3 (housing 1), it is possible to prevent the link member 49 from wearing down or being damaged by external debris. Furthermore, as will be described later, compressed air for air blowing is supplied to the link chamber 48, which further suppresses the entry of debris into the link chamber 48 (housing 1 in which the link member 49 is positioned), and as a result, it is possible to further prevent the link member from wearing down or being damaged by debris. In addition, since the link member 49 is positioned inside the housing 1, a compact clamping device can be made.

[0059] One end of the link member 49, the first end 51, is positioned on the clamp rod 29 side. A recess 52 into which the first end 51 is inserted is formed on the lower side surface of the connecting member 31 that constitutes the clamp rod 29. The first end 51 is formed such that it pushes the axis C2 of the clamp rod 29 at the lower (base end) side of the recess 52 almost straight downward (towards the base end). Therefore, when the clamp rod 29 is locked, it is unlikely that a load will be generated that causes the axis C2 of the clamp rod 29 to tilt. The other end of the link member 49, the second end 53, is pushed from below by the tip of the piston rod 11.

[0060] Furthermore, an air supply passage 54 for air blowing is formed inside the lower housing 2. The compressed air for air blowing supplied to the air supply passage 54 is discharged to the outside of the housing 1 by passing through, for example, the link chamber 48, the spring chamber 44, the hole 55 formed at the lower end of the connecting member 31, the hole 56 formed in the connecting member 31 above the hole 55, and the gap between the gripper 35 and the cover member 33, in that order.

[0061] Furthermore, an air passage 58 is formed in the upper housing 3, which opens at a seating surface 57 formed on the upper surface of the upper housing 3. The compressed air for air blowing supplied to the air supply passage 54 passes through the link chamber 48 and the air passage 58 in that order, in addition to the above-mentioned path, before being discharged to the outside of the housing 1.

[0062] The clamping device with the above configuration operates as follows:

[0063] In the release state shown in Figure 1, compressed air is discharged from the first locking chamber 16 and the second locking chamber 17, while compressed air is supplied to the first release chamber 23 and the second release chamber 24. As a result, the piston rod 11 descends and the clamp rod 29 is raised by the release spring 47. The support cylinder 34, the cover member 33, and the gripper 35 are held in the raised position by the spring 45, and the gripper 35 is in a reduced diameter state due to the elastic force of the ring 39. The gripper 35 and the clamp rod body 30 are positioned coaxially with the axis of the connecting member 31 due to the elastic force of the dust seal 40.

[0064] When switching from the released state shown in Figure 1 to the locked state shown in Figure 2, first, in the released state, the workpiece W is lowered by some lifting mechanism or by its own weight, and the tip of the clamp rod body 30 on which the gripper 35 is positioned is inserted into the hole 32 of the workpiece W. As the tip of the clamp rod body 30 is inserted, the lower surface of the workpiece W is supported by the seating surface 57 of the upper housing 3.

[0065] Next, the compressed air from the first release chamber 23 and the second release chamber 24 is discharged, and compressed air is supplied to the first lock chamber 16 and the second lock chamber 17. As a result, the compressed air in the first lock chamber 16 pushes the first piston body 9 upward against the piston rod 11, and the compressed air in the second lock chamber 17 pushes the second piston body 10 upward against the piston rod 11. This causes the piston rod 11 to rise (move towards the tip). As the piston rod 11 rises, the tip of the piston rod 11 pushes the second end 53 of the link member 49 from below. As the second end 53 is pushed from below, the link member 49 rotates counterclockwise (as shown in the figure), and the first end 51 of the link member 49 pushes the axis C2 of the connecting member 31 (clamp rod 29) downward (towards the base end). Then, the clamp rod 29 (clamp rod body 30 and connecting member 31) descends against the biasing force of the release spring 47 relative to the gripper 35, which is held in the raised position by the spring 45. That is, the clamp rod 29 moves in the direction toward the base end of the axial direction Z. The direction toward the base end is the locking direction of the clamp rod 29. Note that the point where the first end 51 presses is not precisely on the axis C2, but may be slightly offset from the axis C2 (the same applies to other embodiments and modifications).

[0066] As a result, the wedge surface 30b of the clamp rod body 30 expands the diameter of the gripper 35 (moves radially outward), and the gripper 35 engages with the inner circumferential surface of the hole 32 in the workpiece W. Subsequently, the downward force of the clamp rod 29 pulls the workpiece W downward through the hole 32, as the gripper 35, which is tightly gripped and in close contact with the inner circumferential surface of the hole 32, moves downward against the biasing force of the spring 45. As a result, the workpiece W is strongly pressed against the seating surface 57 of the upper housing 3.

[0067] When switching from the locked state shown in Figure 2 to the released state shown in Figure 1, the compressed air in the first lock chamber 16 and the second lock chamber 17 is discharged, and compressed air is supplied to the first release chamber 23 and the second release chamber 24. As a result, the compressed air in the first release chamber 23 pushes the first piston body 9 downwards against the piston rod 11, and the compressed air in the second release chamber 24 causes the second piston body 10 to descend. This causes the piston rod 11 to descend. As the piston rod 11 descends, the tip of the piston rod 11 tries to separate from the second end 53 of the link member 49, and the link member 49 is released from its restraint by the piston rod 11. As a result, the biasing force of the spring 45 causes the support cylinder 34, the cover member 33, and the gripper 35 to rise, and the biasing force of the release spring 47 causes the clamp rod 29 (clamp rod body 30 and connecting member 31) to rise. Furthermore, as the first end 51 of the link member 49 is pulled up by the connecting member 31, the link member 49 rotates clockwise in the diagram. The support cylinder 34, cover member 33, and gripper 35 are held in the raised position by the spring 45, and the gripper 35 is reduced in diameter (moves radially inward) by the elastic force of the ring 39.

[0068] Figure 3 shows a modified example of the first embodiment. The clamping device of this modified example differs from that of the first embodiment in that the biasing means for biasing the support cylinder 34 upward (towards the tip). Note that, for each component constituting the clamping device of this modified example, the same reference numerals are used for components that are the same as those constituting the clamping device of the first embodiment (the same applies to the embodiments and modified examples shown in Figure 4 and later).

[0069] The differences between the configuration of the clamping device in the first embodiment and the configuration of the clamping device in this modified example are as follows.

[0070] In this modified example, a fluid-pressure-driven support piston 59 is used as a biasing means to bias the support cylinder 34 upward (towards the tip). The support piston 59 is positioned in a spring chamber 44 formed inside the lower housing 2 below the support cylinder 34, similar to the spring 45 used as a biasing means in the first embodiment. The support piston 59 is inserted into the spring chamber 44 in a tightly sealed manner, allowing it to move vertically (axial direction Z). The support piston 59 has a cylindrical hole 59a to secure space for the release spring 47, and comprises a large-diameter portion 60 similar to the piston body and a small-diameter portion 61 similar to the piston rod.

[0071] An annular biasing chamber 62 is provided below the large-diameter section 60. Compressed air, as a pressurized fluid, is supplied to and discharged from this biasing chamber 62 through a biasing passage 63 formed in the lower housing 2. The biasing passage 63 is in communication with the second locking chamber 17 (locking chamber) or the port-side passage 19 (locking passage).

[0072] In the first embodiment, the spring 45, acting as a biasing means, constantly biases the support cylinder 34 upward (towards the tip). In this modified example, the support piston 59 biases the support cylinder 34 upward (towards the tip) when the clamping device is switched from the released state to the locked state, and when it is in the locked state. In the released state, the release spring 47 biases the gripper 35 upward via the connecting member 31, the support cylinder 34, and the cover member 33.

[0073] Figures 4 and 5 show a second embodiment of the present invention. The clamping device of the second embodiment differs from that of the first embodiment in the location where the pivot shaft 50 is supported.

[0074] In the first embodiment, the pivot shaft 50 is supported by the upper housing 3. In contrast, in the second embodiment, the pivot shaft 50 is supported by the connecting member 31 that constitutes the clamp rod 29. In the second embodiment, the pivot shaft 50 is located on the first end 51 side of the link member 49.

[0075] The link member 49 is supported by a pivot shaft 50 and is rotatable about the axis of the pivot shaft 50. The pivot shaft 50 is fixed to a connecting member 31 at its end. In this embodiment, the pivot shaft 50 is immobile and the link member 49 is rotatable relative to the pivot shaft 50, however, the pivot shaft 50 may be rotatable relative to the connecting member 31 and the link member 49 may be fixed to the pivot shaft 50.

[0076] The link member 49 has a ridge 49a (protrusion) formed on its upper surface between the first end 51 and the second end 53. When the clamping device is switched from the released state shown in Figure 4 to the locked state shown in Figure 5, the link member 49 rotates counterclockwise in the illustration as the second end 53 is pushed from below. At this time, the ridge 49a contacts the ceiling wall of the link chamber 48, and using the ridge 49a as a fulcrum, the first end 51 pushes the axis C2 of the connecting member 31 (clamp rod 29) downward (towards the base end). Note that the ridge 49a may be in contact with the ceiling wall of the link chamber 48 even when it is in the released state.

[0077] Figure 6 shows a third embodiment of the present invention. The clamping device of the third embodiment differs from that of the first embodiment in that the location supporting the pivot shaft 50 is similar to that of the clamping device of the second embodiment.

[0078] In the third embodiment, the pivot shaft 50 is supported at the tip of the piston rod 11. In the third embodiment, the pivot shaft 50 is located on the second end 53 side of the link member 49.

[0079] The link member 49 is supported by a pivot shaft 50 and is rotatable about the axis of the pivot shaft 50. The pivot shaft 50 is fixed to the tip of the piston rod 11. In this embodiment, the pivot shaft 50 is immovable and the link member 49 is rotatable relative to the pivot shaft 50, however, the pivot shaft 50 may be rotatable relative to the piston rod 11 and the link member 49 may be fixed to the pivot shaft 50.

[0080] Similar to the second embodiment, the link member 49 has a ridge 49a (protrusion) formed on its upper surface between the first end 51 and the second end 53. When the clamping device is switched from the released state to the locked state, the link member 49 is pushed upward on the second end 53 side together with the piston rod 11 as the second end 53 is pushed from below, and rotates counterclockwise as shown in the figure. At this time, the ridge 49a contacts the ceiling wall of the link chamber 48, and using the ridge 49a as a fulcrum, the first end 51 pushes the axis C2 of the connecting member 31 (clamp rod 29) downward (towards the base end). Note that the ridge 49a may be in contact with the ceiling wall of the link chamber 48 even when it is in the released state.

[0081] Figure 7 shows a modified version of the first embodiment. The clamping device in this modified version differs from that of the first embodiment in the configuration of the piston 8.

[0082] The piston 8 in the first embodiment is a so-called tandem type piston and comprises two (or more) piston bodies. In contrast, the piston 8 in this modified example comprises only one piston body 9. The piston 8 comprises a piston body 9 and a piston rod 11, and the piston body 9 and the piston rod 11 are integrally formed. However, the piston body 9 and the piston rod 11 may be separate parts, as in the first embodiment. Since it comprises only one piston body 9, there is also only one locking chamber 16 and one release chamber 23. Furthermore, there is also only one release passage 26.

[0083] Figure 8 shows a modified example of the first embodiment. This modified clamping device differs from the first embodiment in that it has a biasing means for biasing the clamping rod 29 upward (towards the tip).

[0084] In the first embodiment, a release spring 47 located in the spring chamber 44 constitutes a biasing means that biases the clamp rod 29 upward (towards the tip). In contrast, in this modified example, the release spring 47 is located in the link chamber 48. One end of the release spring 47 is fitted into a hole 49b formed on the upper surface of the link member 49, and the other end is fitted into a hole 48a formed in the ceiling wall of the link chamber 48. In this modified example, the release spring 47 biases the clamp rod 29 (connecting member 31) upward (towards the tip) via the link member 49.

[0085] Figures 9A to 9C show modified versions of the link member 49 and the connecting member 31 that constitutes the clamp rod 29. Figure 9A corresponds to an enlarged view of only the parts showing the link member 49 and the connecting member 31 in the illustration of the clamp device shown in Figure 1. The pivot shaft 50 shown in Figures 9A and 9C is supported by the upper housing 3, just as in the clamp device shown in Figure 1. Note that the pivot shaft 50 shown in Figures 9A and 9C may be configured to be supported by the connecting member 31, as in the clamp device shown in Figure 4, by changing its position on the link member 49, etc. Similarly, the pivot shaft 50 shown in Figures 9A and 9C may be configured to be supported at the tip of the piston rod 11, as in the clamp device shown in Figure 6, by changing its position on the link member 49, etc.

[0086] The first end 51 of the link member 49 shown in Figures 9A to 9C has a bifurcated shape with a 1-1 end 65 and a 1-2 end 66.

[0087] A recess 64a into which the 1-1 end portion 65 is inserted and a recess 64b into which the 1-2 end portion 66 is inserted are formed on the side surface of the connecting member 31. Recesses 64a and 64b are formed on opposite sides of the side surface of the connecting member 31. Recesses 64a and 64b together constitute a recess 64 into which the 1 end portion 51 is inserted. The 1-1 end portion 65 pushes approximately straight downward (towards the base) portion of the surface 69a of the connecting member 31 on the lower side (base side) of the recess 64. Also, the 1-2 end portion 66 pushes approximately straight downward (towards the base side) portion of the surface 69b of the connecting member 31 on the lower side (base side) of the recess 64.

[0088] Parts 69a and 69b correspond to multiple parts of the clamp rod 29 that are equally spaced around the axis C2 of the clamp rod 29. "Equally spaced around the axis C2" means that the parts are in positions with equal phase difference from each other around the axis C2 and are at the same distance from the axis C2. To explain using this embodiment as an example, parts 69a and 69b in the recess 64 are at positions with an angle difference of 180 degrees around the axis C2 and are at the same distance from the axis C2.

[0089] When the second end 53 is pushed from below by the tip of the piston rod 11, the first end 51 pushes downward (towards the base end) multiple parts (in this embodiment, parts 69a and 69b) of the clamp rod 29 (connecting member 31) that are equally spaced around the axis C2 of the clamp rod 29 in the recess 64, and as a result the clamp rod 29 moves towards the base end. In this case, the movement of the clamp rod is more stable compared to when only one part of the clamp rod 29 (connecting member 31) is pushed by the link member.

[0090] The multiple portions pressed by the first end 51 of the clamp rod 29 (connecting member 31) are not limited to two portions such as portion 69a and portion 69b. For example, the multiple portions pressed by the first end 51 may be three portions located at an angle difference of 120 degrees around the axis C2, or four portions located at an angle difference of 90 degrees around the axis C2. In other words, the multiple portions pressed by the first end 51 of the clamp rod 29 (connecting member 31) may be multiple portions located at positions with equal phase differences from each other around the axis C2 and at the same distance from the axis C2. The shape and dimensions of the first end 51 (link member 49) are designed as appropriate in accordance with the above. In this embodiment, as described above, the first end 51 has a bifurcated shape with a 1-1 end 65 and a 1-2 end 66.

[0091] Between the 1-1 end 65 and the 1-2 end 66, a wall 67 is provided that passes through the axis C2 of the clamp rod 29 and constitutes a part of the clamp rod 29 (connecting member 31). This wall 67 increases the rigidity of the clamp rod 29 (connecting member 31), and as a result, the movement of the clamp rod 29 becomes stable. Note that the wall 67 is optional.

[0092] The holes 68 formed in the wall 67 and penetrating the wall 67 are holes through which compressed air for air blowing flows.

[0093] The present invention is not limited to the embodiments described above, and it is possible to combine elements of the embodiments as appropriate or to make various modifications to the embodiments without departing from the spirit of the invention.

[0094] For example, the above embodiment can be modified as follows:

[0095] In the link member 49 shown in Figures 1 to 3 and Figures 7 to 9 (Figures 9A to 9C), the horizontal distance from the engagement position between the tip of the piston rod 11 and the link member 49 (second end 53) to the axis of the pivot shaft 50 may be longer than the horizontal distance from the engagement position between the connecting member 31 and the link member 49 (first end 51) to the axis of the pivot shaft 50. In this case, the force with which the piston rod 11 pushes the connecting member 31 downward (towards the base end) is increased via the link member 49 and transmitted to the connecting member 31. As a result, the object to be fixed (workpiece W) can be clamped more strongly.

[0096] In all of the above embodiments and modifications, the link member 49 is supported by the pivot shaft 50, but the pivot shaft 50 may be omitted. Even without the pivot shaft 50, by appropriately designing the shape and dimensions of each part of the link member 49, the link member 49 can be rotated using the ceiling wall of the link chamber 48 as a pivot point, so that the first end 51 pushes the axis C2 portion of the clamp rod 29.

[0097] The orientation of the clamping device may be inverted, oriented sideways, or even at an angle, relative to the example up-and-down orientation.

[0098] The pressurized fluid used to operate the clamping device may be pressurized oil or any other liquid instead of compressed air.

[0099] An example has been shown in which three grippers 35 and wedge surfaces 30b are arranged at predetermined intervals in the circumferential direction, but two, four, or five or more grippers 35 and wedge surfaces 30b may also be arranged.

[0100] The object to be fixed may not be the workpiece W, but rather a workpiece pallet, a mold, or the like. [Explanation of Symbols]

[0101] 1: Housing, 7: Cylinder bore, 8: Piston, 9: First piston body (piston body), 11: Piston rod, 29: Clamp rod, 30: Clamp rod body, 31: Connecting member, 32: Hole, 34: Support cylinder, 34a: Cylinder bore, 35: Gripper (pressing member), 45: Spring (biasing means), 48: Link chamber, 49: Link member, 50: Pivot shaft, 51: First end, 52: Recess, 53: Second end, 54: Air supply passage, 59: Support piston (biasing means), 64: Recess, 65: 1-1 end, 66: 1-2 end, 67: Wall, C1: Piston axis, C2: Clamp rod axis, W: Workpiece (fixed object).

Claims

1. Housing (1), A piston (8) is inserted into a cylinder bore (7) formed in the housing (1) so as to be movable in the axial direction of the cylinder bore (7), and is a fluid-pressure driven piston (8) comprising a piston body (9) and a piston rod (11), A clamp rod (29) inserted into the housing (1) so as to be movable in the axial direction, the clamp rod (29) having an axis (C2) that is away from the axis (C1) of the piston (8) in a direction perpendicular to the axial direction, A link member (49) disposed inside the housing (1), which is a link member (49) that interlocks the clamp rod (29) and the piston rod (11), Equipped with, The first end (51), which is one end of the link member (49), is positioned on the clamp rod (29) side. The second end (53), which is the other end of the link member (49), is pressed by the tip of the piston rod (11), causing the first end (51) to press against the axial center (C2) of the clamp rod (29), or multiple portions of the clamp rod (29) that are equally spaced around the axial center (C2), causing the clamp rod (29) to move toward the base end in the axial direction. Clamping device.

2. In the clamping device of claim 1, The first end portion (51) is inserted into a recess (52) formed on the side surface of the clamp rod (29). When the second end (53) is pressed by the tip of the piston rod (11), the first end (51) pushes the axial center (C2) of the clamp rod (29) in the recess (52) toward the base end, causing the clamp rod (29) to move toward the base end. Clamping device.

3. In the clamping device of claim 1, The first end portion (51) is inserted into a recess (64) formed on the side surface of the clamp rod (29). As the second end (53) is pressed by the tip of the piston rod (11), the first end (51) pushes multiple portions of the clamp rod (29) that are equally spaced around the axis (C2) of the clamp rod (29) in the recess (64) toward the base end, causing the clamp rod (29) to move toward the base end. Clamping device.

4. In the clamping device of claim 3, The first end (51) has a bifurcated shape with a first-first end (65) and a first-second end (66). Between the first-first end (65) and the first-second end (66), a wall (67) is provided that passes through the axis (C2) of the clamp rod (29) and constitutes a part of the clamp rod (29). Clamping device.

5. In the clamping device according to claim 1 or 2, The aforementioned base end direction is the locking direction of the clamp rod (29), The piston rod (11) protrudes from the piston body (9) toward the tip in the axial direction, As the piston rod (11) moves toward the tip, the clamp rod (29) moves toward the base end, opposite to the direction toward the tip, via the link member (49). Clamping device.

6. In the clamping device according to claim 1 or 2, The link member (49) is supported by a pivot shaft (50), The pivot shaft (50) is supported by the housing (1). Clamping device.

7. In the clamping device according to claim 1 or 2, The link member (49) is supported by a pivot shaft (50), The pivot shaft (50) is supported by the clamp rod (29). Clamping device.

8. In the clamping device according to claim 1 or 2, The link member (49) is supported by a pivot shaft (50), The pivot shaft (50) is supported at the tip of the piston rod (11). Clamping device.

9. In the clamping device according to claim 1 or 2, A pressing member (35) is positioned on the outer circumference of the tip of the clamp rod (29) so as to be inserted into the hole (32) of the object to be fixed (W) and to be in close contact with the inner circumferential surface of the hole (32), A support cylinder (34) is positioned inside the housing (1) so as to push the pressing member (35) toward the tip side in the axial direction, and the support cylinder (34) has a cylindrical hole (34a) into which the clamp rod (29) is inserted, A biasing means (45, 59) for biasing the support cylinder (34) toward the tip side, the biasing means (45, 59) being arranged inside the housing (1), A clamping device equipped with the following features.

10. In the clamping device of claim 9, The biasing means (59) is a fluid pressure driven support piston (59). Clamping device.

11. In the clamping device according to claim 1 or 2, The link member (49) is located in a link chamber (48) formed inside the housing (1). Compressed air for air blowing is supplied to the link chamber (48) from the air supply passage (54) formed in the housing (1). Clamping device.

12. In the clamping device according to claim 1 or 2, The clamp rod (29) has, in order from the tip side, a clamp rod body (30) and a connecting member (31). Clamping device.

Images