Clamp device

Abstract

To provide a clamp device which can ease an impact caused when a workpiece is clamped with a simple structure.SOLUTION: When a piston rod 6 which is moved by a pressure fluid supplied from a pipe connection port 12b engages with a cylinder body 2, a flow rate of the pressure fluid discharged from a cylinder chamber 4a is changed by a cushioning mechanism 17 included in the cylinder body 2 to reduce a moving speed of the piston rod 6 and kinetic energy of the piston rod 6. Thus, an impact caused when a workpiece W is clamped can be eased.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a clamping device in which a clamper attached to a piston rod that reciprocates due to pressure fluid is adapted to clamp and unclamp a workpiece. [Background technology]

[0002] Conventionally, the above clamping device has a piston housed in a cylinder chamber formed inside by closing the lower end of a cylinder body, a piston rod protruding outward from the upper end of the cylinder body is connected to the piston, and a clamper attached to the piston rod is clamped and unclamped to a workpiece by pressure fluid supplied to the cylinder chamber from a pair of piping connection ports provided on the cylinder body. In such a clamping device, as disclosed in Patent Document 1, a flow rate control valve mechanism capable of adjusting the flow rate of pressurized fluid is provided in the wall portion of the outer circumferential side wall portion of the head side end wall member, and when an output member (piston rod) is in a predetermined operating range in the forward and backward directions, the output member and the flow rate control valve mechanism work together to reduce the flow rate of the pressurized fluid, thereby slowing down the speed of the piston member when clamping the clamping object and mitigating the impact on the clamping object. Also, as in the pressurized fluid cylinder of Patent Document 2, covers attached to both ends of a tube are formed with a communication passage that directly connects a piping connection port to the cylinder chamber, and a communication passage that connects to the piping connection port via a cushion chamber into which a piston can be fitted, and when the piston is fitted into the cushion chamber, the communication passage that connects to the piping connection port via the cushion chamber is blocked, thereby restricting the flow rate of pressurized fluid discharged from the cylinder chamber, and furthermore, a cylinder capable of adjusting the flow rate by an opening adjustment device is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-20263 A [Patent Document 2] Japanese Utility Model Application Publication No. 53-71198 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned Patent Document 1, a flow rate control valve mechanism 30 consisting of a plurality of parts such as a valve body 34 is provided in the wall of the outer peripheral side wall of the head-side end wall member 10B, and the pressurized fluid flows to the flow rate control valve mechanism 30 through the passages 21c and 21d formed in the main clamp body 10A. Therefore, the flow rate control valve mechanism 30 consisting of a plurality of small parts must be provided in the head-side end wall member 10B, which is difficult to use in a small clamp device. Furthermore, although it is possible to use a configuration for adjusting the flow rate of the pressurized fluid discharged from the cylinder chamber as in Patent Document 2 in the above-mentioned clamp device, the opening adjustment device disposed between the two communication passages and the piping connection port has a complex configuration, which is difficult to use in a small clamp device. In view of the above problems, an object of the present invention is to provide a clamping device that has a simple configuration and is capable of mitigating the impact that occurs when clamping a workpiece. [Means for solving the problem]

[0005] The present invention is characterized in that the cylinder body is provided with a cushion mechanism, and when the piston rod engages with the cylinder body, the cushion mechanism slows down the moving speed of the piston rod and reduces the kinetic energy of the piston rod.

[0006] The cylinder body is provided with a stepped through hole, which is connected to a cushion passage communicating with the cylinder chamber and a first passage communicating with a piping connection port, and a cushion mechanism consisting of the large diameter hole of the stepped hole, the cushion passage, and the first passage fits a large diameter portion of the piston rod into the large diameter hole, and then the pressurized fluid in the cylinder chamber passes through the cushion passage, the large diameter hole, and the first passage and is discharged to the piping connection port, thereby slowing down the moving speed of the piston rod and reducing the kinetic energy of the piston rod.

[0007] The present invention is also characterized in that a needle valve is provided in the middle of the cushion flow passage to adjust the flow rate of the pressure fluid passing through the cushion flow passage.The present invention is also characterized in that the clamp device is composed of parts made of a resin material. Effect of the Invention

[0008] In the present invention, when the piston rod, which is moved by the pressure fluid supplied from the piping connection port, engages with the cylinder body, the flow rate of the pressure fluid discharged from the cylinder chamber is changed by the cushion mechanism provided in the cylinder body, thereby slowing down the movement speed of the piston rod and reducing the kinetic energy of the piston rod. Therefore, it is possible to mitigate the impact when clamping the workpiece. In addition, a cushion flow path communicating with the cylinder chamber and a first flow path communicating with the piping connection port are connected to the stepped through hole drilled in the cylinder body, and after the large diameter part provided on the piston rod is fitted into the large diameter hole by the cushion mechanism composed of the large diameter hole of the stepped hole, the cushion flow path, and the first flow path, the pressure fluid in the cylinder chamber is discharged from the cushion flow path through the large diameter hole and the first flow path to the piping connection port, thereby slowing down the movement speed of the piston rod and reducing the kinetic energy of the piston rod. Therefore, the simple configuration makes it easy to use even in a small clamping device.

[0009] Furthermore, by installing a needle valve in the middle of the cushion flow path and adjusting the flow rate of the pressure fluid passing through the cushion flow path, it becomes possible to adjust the impact force when clamping the workpiece simply by operating the needle valve. Also, by configuring the parts by molding them from a resin material, heat treatment or surface treatment is not required for the sliding parts, making the clamp device cheaper and lighter overall. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view of the clamping device of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Diagram 3] 13A and 13B are diagrams illustrating a state in which the moving speed of the piston rod becomes slow. [Figure 4] FIG. 13 is a diagram showing an unclamped state of the workpiece. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the clamping device 1 shown in FIG. 1, the lower end of the cylinder body 2 is closed with an end member 3, and a piston 5 is housed in a cylinder chamber 4 formed inside. The piston 5 divides the cylinder chamber 4 into a first and a second cylinder chamber 4a, 4b. A piston rod 6 protruding outward from the upper end of the cylinder body 2 is connected to the piston 5, and the piston rod 6 is guided through a stepped through hole 7 drilled in the cylinder body 2. A packing member 8 is disposed in the large diameter hole 7a of the through hole 7, and the packing member 8 is adapted to contact the large diameter portion 6a of the piston rod 6. An annular recessed groove 5a is provided in the piston 5, and a protruding portion 2a into which the recessed groove 5a of the piston 5 fits is provided in the cylinder body 2. A clamper 10 that clamps an object to be clamped (workpiece W) is attached to the tip side of the piston rod 6 via a pin member 9. One end of a link member 11, the other end of which is supported by the cylinder body 2 so as to be able to swing freely, is connected to the middle portion of the clamper 10. As the piston rod 6 moves, the tip end side of the clamper 10 swings about the pin member 9 as a fulcrum.

[0012] The cylinder body 2 is provided with a pair of pipe connection ports 12a, 12b for supplying pressure fluid from the outside to each of the cylinder chambers 4. A second flow path 13 communicating with the second cylinder chamber 4b is connected to the pipe connection port 12b. A first flow path 14 communicating with the large diameter hole 7a of the stepped hole 7 is connected to the pipe connection port 12a. A cushion flow path 15 communicating with the first cylinder chamber 4a is connected to the large diameter hole 7a. The piston 5 can be reciprocated in the cylinder chamber 4 by supplying pressure fluid from the pipe connection port 12a (12b) to the first (second) cylinder chamber 4a (4b) and discharging the pressure fluid from the second (first) cylinder chamber 4b (4a) from the pipe connection port 12b (12a). A well-known needle valve 16 is installed in the middle of the cushion flow path 15 to adjust the flow rate of pressure fluid passing through the cushion flow path 15.

[0013] The clamping device 1 having the above configuration is installed near the workpiece W placed on the base 20 in order to clamp the workpiece W. When clamping the workpiece W, from the state shown in FIG. 4, the pressure fluid passes through the flow path 21 provided in the base 20 and is supplied to the second cylinder chamber 4b through the second flow path 13 from the piping connection port 12b, and the pressure fluid in the first cylinder chamber 4a is discharged from the cushion flow path 15 and the first flow path 14 to the piping connection port 12a, thereby causing the movement of the piston rod 6 to swing the clamper 10. As shown in FIG. 3, when the large diameter portion 6a of the piston rod 6 fits into the large diameter hole 7a just before the clamper 10 clamps the workpiece W, the discharge of the pressure fluid from the large diameter hole 7a through the first flow path 14 to the piping connection port 12a is stopped in that state, but the pressure fluid in the first cylinder chamber 4a is discharged through the cushion flow path 15, the large diameter hole 7a, and the first flow path 14 to the piping connection port 12a. Therefore, the cushion mechanism 17 of the present invention changes the flow rate of pressurized fluid discharged from the first cylinder chamber 4a to the piping connection port 12a before and after the large diameter portion 6a of the piston rod 6 is fitted into the large diameter hole 7a.

[0014] 2, the pressure fluid is supplied from the pipe connection port 12a through the first flow path 14 to the large diameter hole 7a, and the pressure fluid in the second cylinder chamber 4b is discharged from the second flow path 13 to the pipe connection port 12b, so that the piston rod 6 moves to swing the clamper 10. Furthermore, when the engagement between the large diameter portion 6a of the piston rod 6 and the large diameter hole 7 is released, the pressure fluid supplied from the pipe connection port 12a is supplied from the large diameter hole 7a to the first cylinder chamber 4a, and is also supplied from the cushion flow path 15 to the first cylinder chamber 4a. Therefore, the flow rate of the pressure fluid supplied to the first cylinder chamber 4a changes before and after the large diameter portion 6a of the piston rod 6 is engaged with the large diameter hole 7a.

[0015] From the above, in the clamping device 1 of the present invention, when the piston rod 6, which is moved by the pressure fluid supplied from the pipe connection port 12b, engages with the cylinder body 2, the flow rate of the pressure fluid discharged from the cylinder chamber 4a is changed by the cushion mechanism 17 provided in the cylinder body 2, thereby slowing down the moving speed of the piston rod 6 and reducing the kinetic energy of the piston rod 6. Thus, it is possible to mitigate the impact when clamping the workpiece W. In addition, the stepped through hole 7 drilled in the cylinder body 2 is connected to the cushion flow path 15 communicating with the cylinder chamber 4a and the first flow path 14 communicating with the pipe connection port 12a, and after the large diameter portion 6a provided on the piston rod 6 is fitted into the large diameter hole 7a by the cushion mechanism 17 consisting of the large diameter hole 7a of the stepped hole 7, the cushion flow path 15, and the first flow path 14, the pressure fluid in the cylinder chamber 4a is discharged from the cushion flow path 15 to the pipe connection port 12a through the large diameter hole 7a and the first flow path 14, thereby slowing down the moving speed of the piston rod 6 and reducing the kinetic energy of the piston rod 6. Therefore, the clamp device 1 has a simple configuration and can be easily used even in a small clamp device.

[0016] Furthermore, by installing a needle valve 16 midway through the cushion flow path 15 and adjusting the flow rate of the pressure fluid passing through the cushion flow path 15, it is possible to adjust the impact force when clamping the workpiece W simply by operating the needle valve 16. Also, while the clamp device 1 of this embodiment is constructed from parts molded from aluminum, iron, or the like, if the parts are constructed from a resin material, specifically from CFRP material, heat treatment, surface treatment, and the like are not required for the sliding parts, making the clamp device 1 cheaper as a whole than clamp devices equipped with conventional cushion mechanisms and enabling the clamp device 1 to be made lighter as a whole. [Explanation of symbols]

[0017] 1 Clamping device 2 Cylinder body 4 Cylinder chamber 5 Piston 6 Piston rod 7 Through hole 7a Large diameter hole 12a Pipe connection port 12b Piping connection port 14 First flow path 15 Cushion channel 16 Needle valve 17 Cushioning mechanism

Claims

1. A clamping device in which a piston is stored in a cylinder chamber formed inside a cylinder body by closing the lower end of the cylinder body, a piston rod protruding outward from the upper end of the cylinder body is connected to the piston, and a clamper attached to the piston rod is clamped and unclamped to a workpiece by pressure fluid supplied to the cylinder chamber from a pair of piping connection ports provided on the cylinder body. The clamping device is characterized in that the cylinder body is provided with a cushion mechanism, and when the piston rod engages with the cylinder body, the cushion mechanism decelerates the moving speed of the piston rod and reduces the kinetic energy of the piston rod.

2. 1. A clamping device comprising: a cylinder body having a lower end thereof closed and a cylinder chamber formed therein; a piston connected to the piston; a piston rod protruding outward from an upper end of the cylinder body; and a clamper attached to the piston rod clamps and unclamps a workpiece by pressure fluid supplied to the cylinder chamber from a pair of piping connection ports provided on the cylinder body. In this clamping device, a cushion passage communicating with the cylinder chamber and a first passage communicating with the piping connection port are respectively connected to the stepped through hole formed in the cylinder body, and a cushion mechanism consisting of a large diameter hole of the stepped hole, the cushion passage, and the first passage discharges pressure fluid in the cylinder chamber from the cushion passage through the large diameter hole and the first passage to the piping connection port after a large diameter portion provided on the piston rod is fitted into the large diameter hole, thereby slowing down the moving speed of the piston rod and reducing the kinetic energy of the piston rod.

3. 3. The clamp device according to claim 1, further comprising a needle valve disposed midway along the cushion flow path for adjusting the flow rate of the pressure fluid passing through the cushion flow path.

4. 4. The clamp device according to claim 1, wherein the clamp device is made of a component made of a resin material.

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