Clamping Device

Abstract

To provide a clamp device which achieves downsizing while achieving stable clamp force.SOLUTION: A clamp device includes: a fluid pressure cylinder fixed to a base body; and an annular member attachable to an object to be fixed. The fluid pressure cylinder includes: a cylinder body; a first piston and a second piston which may reciprocate relative to the cylinder body; a first cylinder chamber where the first piston and the second piston are driven to the fixed side; a second cylinder chamber where the first piston and the second piston are driven to the fixture release side; and an engagement part which may be located at the inner periphery side of the annular member and switch its state between a first state, where the engagement part does not press the annular member, and a second state, where the engagement part presses the annular member to the base body side, in conjunction with reciprocating motion of the first piston and the second piston. The first piston, the first cylinder chamber, the second cylinder chamber, and the second piston are provided so that the first piston, the first cylinder chamber, the second cylinder chamber, and the second piston are arranged in a written order along a first direction from the base body side toward the side of the object to be fixed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present technology relates to clamping devices. [Background technology]

[0002] BACKGROUND ART Clamping devices that fix a movable member such as a work pallet in a state of being aligned with a reference member such as a table of a machining center have been known in the past (for example, Patent Documents 1 to 3 listed below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2011 / 046039 [Patent Document 2] Japanese Patent Application Publication No. 11-333649 [Patent Document 3] Utility Model Registration No. 3219695 Summary of the Invention [Problem to be solved by the invention]

[0004] The clamping device is required to exert a stable clamping force, and at the same time, the clamping device is also required to be compact.

[0005] An object of the present technology is to provide a clamping device that is miniaturized while exerting a stable clamping force. [Means for solving the problem]

[0006] A clamping device according to the present technology is capable of fixing an object to a base body and positioning the object relative to the base body, and includes a fluid pressure cylinder fixed to the base body and an annular member attachable to the object to be fixed. The fluid pressure cylinder includes a cylinder body, first and second pistons reciprocating relative to the cylinder body, a first cylinder chamber that drives the first and second pistons toward a fixing side, a second cylinder chamber that drives the first and second pistons toward a release side, and an engaging portion that can be positioned on the inner periphery of the annular member and that can switch between a first state in which the annular member is not pressed and a second state in which the annular member is pressed toward the base body as the first and second pistons reciprocate. The first piston, the first cylinder chamber, the second cylinder chamber, and the second piston are arranged in this order along a first direction from the base body toward the object to be fixed. [Effects of the Invention]

[0007] According to the present technology, it is possible to reduce the size of the clamp device while allowing the clamp device to exert a stable clamping force. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view showing a first state (unclamped state) of a clamping device according to one embodiment. [Figure 2] FIG. 4 is a longitudinal sectional view showing a second state (clamped state) of the clamping device according to one embodiment. [Figure 3] 3A and 3B are vertical cross-sectional views of the clamping device shown in FIGS. 1 and 2 in different directions. [Figure 4] FIG. 4 is an enlarged view of part IV in FIG. [Figure 5] FIG. 5 is a top cross-sectional view of the clamping device shown in FIGS. 1 to 4. [Figure 6] 6 is an enlarged vertical cross-sectional view showing the structure around a clamping chamber and an unclamping chamber of the clamping device shown in FIGS. 1 to 5. FIG. [Figure 7] FIG. 10 is a vertical cross-sectional view showing a clamping device according to a first modified example. [Figure 8] FIG. 10 is a vertical cross-sectional view showing a clamping device according to a second modified example. [Figure 9] FIG. 10 is a vertical cross-sectional view showing a clamping device according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0010] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the embodiments described below, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0011] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0012] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0013] 1 and 2 are longitudinal cross-sectional views showing a clamping device according to this embodiment, with Fig. 1 showing an unclamped state (first state) and Fig. 2 showing a clamped state (second state).

[0014] The clamping device of this embodiment is capable of fixing a movable member 2 (fixed object) to a reference member 1 (base body) and positioning the movable member 2 relative to the reference member 1 (left-right, up-down and depth directions in Figures 1 and 2).

[0015] The reference member 1 is, for example, a table of a machining center, etc. The movable member 2 is, for example, a work pallet or the like fixed to the table.

[0016] A clamp cylinder 100 may be fixed to the reference member 1. A ring member 200 (annular member) may be fixed to the movable member 2. The ring member 200 is fixed to the movable member 2 by, for example, a bolt or the like. The bolt that fixes the ring member 200 may be inserted from the upper side in the drawing or from the lower side in the drawing.

[0017] The clamp cylinder 100 includes a cylinder body 10, a first piston member 20, a second piston member 30, a clamp chamber 40 (first cylinder chamber), an unclamping chamber 50 (second cylinder chamber), a steel ball 60 (engagement portion / engagement ball), a sealing member 70, and a biasing member 80.

[0018] The bottom of the cylinder body 10 is fitted into a hole 1A in the reference member 1. The position and diameter of the hole 1A can be precisely adjusted to align the cylinder body 10. The cylinder body 10 has ports 11 and 12. Port 11 can be connected to a clamping air pipe 3. Port 12 can be connected to an unclamping air pipe 4.

[0019] The first piston member 20 includes a piston portion 21 and a rod portion 22. The second piston member 30 is fixed to the tip side of the rod portion 22 of the first piston member 20 by a stopper 31. Therefore, the first piston member 20 and the second piston member 30 can reciprocate integrally with respect to the cylinder body 10. A recess 32 is formed on the outer periphery of the second piston member 30.

[0020] A clamping hydraulic fluid is supplied to the clamp chamber 40 via the port 11. This drives the first piston member 20 and the second piston member 30 to the fixed side (downward in the figure). The hydraulic fluid supplied to the clamp chamber 40 can be discharged via the port 11. Air is used as the clamping hydraulic fluid, for example, but the hydraulic fluid is not limited to air. Oil pressure may be used instead of air pressure.

[0021] An unclamping working fluid is supplied to the unclamping chamber 50 via the port 12. This drives the first piston member 20 and the second piston member 30 to the release side (upper side in the figure). The working fluid supplied to the unclamping chamber 50 can be discharged via the port 12. Air, for example, is used as the unclamping working fluid, but the working fluid is not limited to air. Oil pressure may be used instead of air pressure.

[0022] The steel balls 60 are held by the cylinder body 10 and are located on the inner circumferential side of the ring member 200. A plurality of steel balls 60 are provided so as to be lined up in the circumferential direction of the ring member 200. Each steel ball 60 is held by the cylinder body 10. Furthermore, each steel ball 60 is received in a recess 32 of the second piston member 30.

[0023] In the unclamped state (first state) shown in Figure 1, the steel balls 60 do not protrude radially outward from the cylinder body 10 and do not press against the ring member 200. In this state, the movable member 2 can be removed and replaced. In the clamped state (second state) shown in Figure 2, the steel balls protrude radially outward from the cylinder body 10 and press against the ring member 200 toward the reference member 1 (diagonally downward in the figure).

[0024] The sealing member 70 includes a sealing member 71 provided on the outer periphery of the piston portion 21 of the first piston member 20, a sealing member 72 provided between the rod portion 22 of the first piston member 20 and the cylinder body 10, a sealing member 73 provided on the outer periphery of the second piston member 30, and a sealing member 74 provided between the rod portion 22 of the first piston member 20 and the second piston member 30.

[0025] The seal member 71 seals between the clamp chamber 40 and the outside of the cylinder body 10. The seal member 72 seals between the clamp chamber 40 and the unclamping chamber 50. The seal members 73 and 74 seal between the unclamping chamber 50 and the outside of the cylinder body 10.

[0026] The biasing member 80 is provided in the clamp chamber 40. The biasing member 80 illustrated in FIGS. 1 and 2 is a coil spring provided around the rod portion 22. The biasing member 80 biases the piston portion 21 of the first piston member 20 and the cylinder body 10 in directions separating them from each other. As a result, even if the supply of hydraulic fluid pressure for clamping into the clamp chamber 40 is obstructed for some reason, the biasing force of the biasing member 80 can ensure a clamping force for fixing the movable member 2.

[0027] In this way, in the clamp cylinder 100, the first piston member 20, the clamp chamber 40, the unclamping chamber 50, and the second piston member 30 are arranged in this order along the vertical direction (first direction) from the reference member 1 side toward the movable member 2 side. As the second piston member 30 reciprocates, the steel ball 60 moves in the radial direction (second direction), switching between an unclamped state and a clamped state.

[0028] In this specification, even if the unclamping chamber 50 is formed both above and below the piston portion 21 of the first piston member 20, if at least a portion of the unclamping chamber 50 is formed between the clamping chamber 40 and the second piston member 30, it can be interpreted that the first piston member 20, the clamping chamber 40, the unclamping chamber 50, and the second piston member 30 are arranged in the following order: piston portion 21 of the first piston member 20, the clamping chamber 40, the unclamping chamber 50, and the second piston member 30.

[0029] When installing a plurality of clamp cylinders 100 and a plurality of ring members 200 on the reference member 1 and the movable member 2, first, the plurality of clamp cylinders 100 are fixed to the reference member 1. Next, each clamp cylinder 100 clamps one ring member 200. Here, each individual clamp cylinder 100 is positioned horizontally relative to the reference member 1. Therefore, each of the plurality of ring members 200 is also positioned horizontally relative to the reference member 1. Furthermore, the movable member 2 is fixed (bolted) to the plurality of ring members 200. In this way, by using a plurality of clamp cylinders 100 and ring members 200, the movable member 2 can be positioned and fixed to the reference member 1 with a high clamping force.

[0030] Figure 3 is a vertical cross-sectional view of the clamp cylinder 100 taken along a direction different from that of Figures 1 and 2. In the cross-sectional direction shown in Figure 3, the cylinder body 10 has ports 13 and 14. The ports 13 and 14 are connected to the detection air pipes 5A and 5B.

[0031] The cylinder body 10 has a detection port 16 that communicates with the ports 13 and 14. In the clamped state, the ring member 200 closes the detection port 16, causing the air pressure in the detection air pipes 5A and 5B to rise. Therefore, by measuring the air pressure in the detection air pipes 5A and 5B, it is possible to detect whether the clamping operation is normal.

[0032] Fig. 4 is an enlarged view of part IV in Fig. 3. As shown in Fig. 4, the steel ball 60 is held in the holding portion 15 of the cylinder body 10. In addition, an inclined surface 33 is provided on the upper side (movable member 2 side) of the recessed portion 32 of the second piston member 30.

[0033] During clamping operation, the second piston member 30 is driven downward in the figure, and the steel ball 60 is pushed by the inclined surface 33 and presses the inclined surface 210 of the ring member 200 diagonally downward, thereby attracting the ring member 200 downward in the figure.

[0034] The cylinder body 10 has a reference surface 17. The detection port 16 opens onto the reference surface 17.

[0035] During the unclamping operation, the second piston member 30, which is driven upward in the drawing, pushes up the movable member 2. When the movable member 2 is not clamped, the end of the detection port opens on the reference surface 17, so air supplied from the detection air pipes 5A and 5B leaks.

[0036] The inner peripheral surface of the ring member 200 abuts against the outer peripheral surface of the cylinder body 10, thereby positioning it in the horizontal direction. Furthermore, when the ring member 200 is pulled downward during clamping, the abutment surface 220 of the ring member 200 abuts against the reference surface 17 of the cylinder body 10, thereby positioning it in the vertical direction. This closes the detection port 16, preventing air supplied from the detection air pipes 5A and 5B from leaking. By measuring the air pressure in the detection air pipes 5A and 5B with a pressure sensor, it is possible to confirm whether the movable member 2 is being clamped properly. By providing multiple detection ports, it is also possible to detect the tilt of the movable member 2.

[0037] Fig. 5 is a top cross-sectional view of the clamp cylinder 100. The cross section taken along line II-II in Fig. 5 corresponds to Fig. 2, and the cross section taken along line III-III in Fig. 5 corresponds to Fig. 3.

[0038] As shown in FIG. 5 , the clamping air pipe 3, the unclamping air pipe 4, and the detection air pipes 5A and 5B are connected to the cylinder body 10 from directions offset by 90° from one another in the circumferential direction. The cylinder body 10 has a flange portion 18 that protrudes away from the central axis of the cylinder body 10. The clamping air pipe 3, the unclamping air pipe 4, and the detection air pipes 5A and 5B are connected to the flange portion 18. The cylinder body 10 is fixed to the reference member 1 by a fixing member 300 inserted into the flange portion 18. In the clamp cylinder 100, the clamping chamber 40 and the unclamping chamber 50 are both located above the piston portion 21 (on the movable member 2 side). This allows the flange portion 18 to be provided with ports connecting the clamping air pipe 3 and the unclamping air pipe 4. Furthermore, since it is possible to eliminate the need for a cylinder chamber below the piston portion 21, the reference member 1 can be configured as a relatively thin, plate-like member. As a result, the clamp cylinder 100 can be made smaller, particularly in the height direction (the depth direction of the paper in FIG. 5 ).

[0039] Furthermore, as shown in FIG. 5, because the steel balls 60 are arranged on the outer periphery of the second piston member 30 that defines the unclamping chamber 50, it is possible to increase the number of steel balls 60 arranged in the circumferential direction compared to when the steel balls 60 are arranged on the outer periphery of the rod portion 22 of the first piston member 20 (i.e., when the second piston member 30 is not present). As a result, it is possible to more accurately position the ring member 200 using the clamp cylinder 100. In addition, it is possible to reduce the surface pressure acting on each steel ball 60, allowing the steel balls 60 to be made smaller. As a result, it is possible to make the clamp cylinder 100 smaller, particularly in the height direction (the depth direction of the paper in FIG. 5).

[0040] FIG. 6 is an enlarged vertical cross-sectional view showing the structure around the clamping chamber 40 and the unclamping chamber 50 of the clamping device shown in FIGS.

[0041] 6, the cylinder body 10 includes a partition wall portion 10C that separates the clamping chamber 40 from the unclamping chamber 50. The biasing member 80 is provided between the piston portion 21 of the first piston member 20 and the partition wall portion 10C.

[0042] The piston portion 21 of the first piston member 20 includes a recess (first recess) recessed in a direction away from the partition wall portion 10C. This recess is made up of a tapered side surface 21A and a bottom surface 21B.

[0043] The partition wall portion 10C includes a recess 10A (second recess) recessed in a direction away from the piston portion 21 of the first piston member 20. The biasing member 80 is provided so as to be housed in the recess formed in the piston portion 21 and the recess 10A formed in the partition wall portion 10C.

[0044] The partition wall portion 10C includes a protruding portion 10B that protrudes in a direction approaching the second piston member 30. The second piston member 30 includes a recess (third recess) that is recessed so as to receive the protruding portion 10B. This recess is made up of a tapered side surface 30A and a bottom surface 30B.

[0045] 7 to 9 are vertical cross-sectional views showing modified clamp cylinders 100. Each modified example of the clamp cylinder 100 will be described with reference to FIGS.

[0046] In the modification shown in Fig. 7, the clamping air pipes 3A, 3B and the unclamping air pipes 4A, 4B can be connected to the cylinder body 10 from two directions (above and below the reference member 1). The cylinder body 10 is provided with ports 11A, 12A for connecting the clamping air pipe 3A and the unclamping air pipe 4A, and ports 11B, 12B for connecting the clamping air pipe 3B and the unclamping air pipe 4B. Either one of the clamping air pipes 3A, 3B can be selectively used. Either one of the unclamping air pipes 4A, 4B can also be selectively used.

[0047] 8, if any malfunction occurs during the unclamping operation, the back surface 23 of the first piston member 20 is pushed upward using a jig 6 to complete the unclamping operation. In the clamp cylinder 100 according to this embodiment, the unclamping chamber 50 is formed above the piston portion 21, so that the back surface 23 of the first piston member 20 can be exposed to the outside, and operation using the jig 6 becomes possible.

[0048] 9, the position of the first piston member 20 is confirmed using a sensor 7 to confirm the clamped state. In the clamp cylinder 100 according to this embodiment, the unclamping chamber 50 is formed above the piston portion 21, so that the back surface 23 of the first piston member 20 can be exposed to the outside, and measurement using the sensor 7 becomes possible.

[0049] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0050] 1 Reference member (table), 1A Hole portion, 2 Movable member (pallet), 3, 3A, 3B Clamping air pipe, 4, 4A, 4B Unclamping air pipe, 5A, 5B Detection air pipe, 6 Jig, 7 Sensor, 10 Cylinder body, 10A Recess, 10B Protrusion, 10C Bulkhead portion, 11, 11A, 11B, 12, 12A, 12B, 13, 14 Port, 15 Holding portion, 16 Detection port, 17 Reference surface, 18 Flange portion, 20 First piston member, 21 Piston portion, 21A Tapered side surface, 21B Bottom surface, 22 Rod portion, 23 Back surface, 30 Second piston member, 31 Stopper, 32 Recess, 33 Inclined surface, 40 Clamping chamber, 50 Unclamping chamber, 60 Steel ball (engagement tool), 70-74 Sealing member, 80 Biasing member, 100 clamp cylinder, 200 ring member, 210 inclined surface, 220 abutment surface, 300 fixing member (bolt).

Claims

1. A clamping device capable of fixing an object to a base body and positioning the object to the base body, a fluid pressure cylinder fixed to the base body; an annular member attachable to the object to be fixed; The fluid pressure cylinder is A cylinder body; a first piston and a second piston reciprocatable relative to the cylinder body; a first cylinder chamber that drives the first piston and the second piston toward a fixed side; a second cylinder chamber that drives the first piston and the second piston toward the release side; an engaging portion that can be positioned on an inner peripheral side of the annular member and that can switch between a first state in which the engaging portion does not press the annular member and a second state in which the engaging portion presses the annular member toward the base body in accordance with the reciprocating motion of the first piston and the second piston; the first piston, the first cylinder chamber, the second cylinder chamber, and the second piston are arranged in this order along a first direction from the base body side toward the fixed object side, A clamping device, wherein a surface of the first piston opposite to the object to be fixed is exposed to the outside of the cylinder body.

2. The clamping device according to claim 1 , wherein the first piston is connected to the second piston via a rod portion extending along the first direction.

3. the engaging portion includes a plurality of engaging balls held by the cylinder body so as to be aligned in a circumferential direction of the annular member, The clamping device according to claim 1 or 2, wherein the second piston has a recess capable of accommodating at least a portion of the plurality of engaging balls.

4. The clamp device according to claim 1 , wherein the engaging portion moves in a second direction perpendicular to the first direction in accordance with the movement of the second piston.

5. The clamp device according to claim 1 , wherein the cylinder body includes a partition wall that separates the first cylinder chamber from the second cylinder chamber.

6. The clamping device according to claim 5 , further comprising a biasing member provided between the first piston and the partition wall, biasing the first piston toward the fixed side.

7. the first piston includes a first recess recessed in a direction away from the partition wall, the partition wall portion includes a second recess portion recessed in a direction away from the first piston, The clamping device according to claim 6 , wherein the biasing member is provided to be housed in the first recess and the second recess.

8. A clamping device capable of fixing an object to a base body and positioning the object to the base body, a fluid pressure cylinder fixed to the base body; an annular member attachable to the object to be fixed; The fluid pressure cylinder is A cylinder body; a first piston and a second piston reciprocatable relative to the cylinder body; a first cylinder chamber that drives the first piston and the second piston toward a fixed side; a second cylinder chamber that drives the first piston and the second piston toward the release side; an engaging portion that can be positioned on an inner peripheral side of the annular member and that can switch between a first state in which the engaging portion does not press the annular member and a second state in which the engaging portion presses the annular member toward the base body in accordance with the reciprocating motion of the first piston and the second piston; the first piston, the first cylinder chamber, the second cylinder chamber, and the second piston are arranged in this order along a first direction from the base body side toward the fixed object side, the cylinder body includes a partition wall portion that separates the first cylinder chamber and the second cylinder chamber, a biasing member provided between the first piston and the partition wall and biasing the first piston toward the fixed side, the first piston includes a first recess recessed in a direction away from the partition wall, the partition wall portion includes a second recess portion recessed in a direction away from the first piston, the biasing member is provided to be housed in the first recess and the second recess, the partition wall portion includes a protruding portion that protrudes in a direction toward the second piston, The second piston includes a third recess recessed to receive the protrusion.

9. 9. The clamping device according to claim 1, wherein the cylinder body includes a flange portion that protrudes in a direction away from a central axis of the cylinder body, and a supply / discharge port for the working fluid of the first cylinder chamber and the second cylinder chamber is provided in the flange portion.

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