JPH0527306U - Fluid pressure cylinder with speed control mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a fluid pressure cylinder with a speed control mechanism having a short axial length. A hollow portion 10 opening to a pressure chamber 17 on the head side and a diameter-increasing portion 11 on the rod side are formed in a piston rod 9, and a hollow ventilation mandrel 5 is loosely inserted in the hollow portion 10 in a head cover 3,
The rod cover 4 is provided with the recesses 6 that open to the pressure chambers 18 on the rod side, and the axial length is approximately equal to the stroke of the piston 8 and the cross-sectional area is a sinusoidal curve on the outer peripheral surfaces of the ventilation mandrel 5 and the expanded diameter portion 11. Grooves 5a and 11a that change in shape are provided to bring the rings 12 and 13 into contact with their outer peripheral surfaces. [Effect] Since the ventilation mandrel is inserted into the hollow portion provided on the head side of the piston rod, the axial length of the cylinder can be significantly shortened.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fluid pressure cylinder having a piston speed control mechanism.

[0002]

[Prior Art]

 The inventors of the present invention have previously proposed, in Japanese Patent Application No. 2-8 9800, a fluid pressure cylinder with a speed control mechanism that can shorten the stroke time without abrupt fluctuation of the piston speed. The proposed fluid pressure cylinder is suitable for moving easily damaged workpieces such as semiconductor wafers because the piston does not have rapid velocity fluctuations. If the mechanism is provided on both sides of the piston, there is a problem that the axial length of the fluid pressure cylinder becomes long.

[0003]

[Problems to be solved by the device]

 The problem to be solved by the present invention is to provide a fluid pressure cylinder in which the moving speed of the piston in both directions can be controlled and the axial length can be shortened.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, a fluid pressure cylinder with a speed control mechanism of the present invention includes a cylinder, a piston that slides in the cylinder, and a piston rod, and a pair of pressure chambers partitioned by a piston from a pair of ports. In a fluid pressure cylinder that supplies and discharges pressure fluid to and from the piston and piston rod to reciprocate, the head cover of the cylinder has a hollow ventilation mandrel whose one end communicates with a port on the head side, and the rod cover has a rod cover. Each of the piston rods has a hollow portion communicating with the port on the side and opening to the pressure chamber on the rod side. Equipped with a rod-side expanded portion that is loosely inserted, and the ventilation mandrel and expanded portion have an axial length on the outer peripheral surface that is approximately equal to the piston stroke, and the cross-sectional area changes smoothly. Provided with a groove, the hollow portion and the recess, is characterized in that it comprises a contact with the ring on the outer peripheral surface of the vent stem and the enlarged diameter portion to the opening to the pressure chamber. In addition, in order to solve the same problem, it is characterized in that the cross-sectional area of the groove is gradually increased from both ends toward the center or changed in a sinusoidal shape.

[0005]

[Action]

 The pressure fluid supplied from the port is supplied to the pressure chamber through the groove formed in the expanded diameter portion of the ventilation mandrel or the piston rod. In this case, since the cross-sectional area of the groove changes smoothly, the speed of the piston does not suddenly change, and the stroke time can be shortened. In addition, since a hollow vent core that communicates with the port on the head side is loosely inserted in the hollow part provided on the piston rod, there is no need to provide an expanded diameter part on the head side of the piston. The length can be greatly shortened.

Furthermore, since the cross-sectional area of the groove is gradually increased from both ends toward the center or changed in a sinusoidal shape, the speed at the start and stop of the piston is small, and the speed in the middle is large. can do.

[0007]

【Example】

 The drawings show an embodiment of the present invention. A cylinder 1 of a fluid pressure cylinder with a speed control mechanism is provided with a cylinder tube 2, a head cover 3 and a rod cover 4 screwed to both axial ends of the cylinder tube 2, and the head cover 3 includes a cylinder. A hollow air-permeable mandrel 5 which is concentric with the tube 2 is attached, and a recess 6 is formed in the rod cover 4. The piston 8 that slides in the cylinder tube 2 is attached to the tip end portion of a piston rod 9, and a hollow portion 10 in which the head side is opened and the ventilation mandrel 5 is loosely inserted into the piston rod 9 and the rod side An enlarged diameter portion 11 that is loosely inserted into the recess 6 is formed, and the hollow portion 10 and the enlarged diameter portion 11 have an axial length that is slightly longer than the stroke of the piston 8.

The ventilation mandrel 5 and the expanded diameter portion 11 have an axial length substantially equal to the stroke of the piston 8 and axial grooves 5a and 11a (FIG. 2) whose cross-sectional areas gradually increase from both ends toward the center. (See FIG. 3), and rings 12 and 13 are attached to the opening of the hollow portion 10 and the opening of the recess 6, respectively, which abut on the outer peripheral surfaces of the ventilation mandrel 5 and the expanded diameter portion 11, respectively. In the illustrated example, the grooves 5a and 11a have the same axial width and a sinusoidal depth as shown in FIG. 4, and the cross-sectional area gradually increases from both ends toward the center. However, the shape of the groove is not limited to this, and may be any shape as long as the cross-sectional area in the axial direction changes smoothly, and a plurality of grooves may be provided as necessary.

The head-side port 15 opened in the head cover 3 communicates with the head-side pressure chamber 17 through the axial hole 19 of the ventilation mandrel 5 and between the hollow portion 10 and the ventilation mandrel 5, and the rod cover 4 The port 16 on the rod side, which is opened at, is communicated with the pressure chamber 18 on the rod side by the recess 6. A head cover plug 22 for fixing the ventilation mandrel 5 is screwed to the head cover 3, and dampers 23, 23 are attached to both sides of the piston 8 in the sliding direction.

FIG. 1 shows a state where the piston 8 has reached the end of the right-hand movement stroke. In this state, when a switching valve (not shown) is switched to supply compressed air from the port 15, the ring 12 causes the ring 12 to move. Since it is in contact with the outer peripheral surface of 5, the air is supplied to the pressure chamber 17 through the groove 5 a of the ventilation mandrel 5. Further, since the air in the pressure chamber 18 is similarly discharged from the port 16 through the groove 11a of the expanded diameter portion 11, the piston 8 and the piston rod 9 move left in the figure. In this case, since the cross-sectional areas of the grooves 5a and 11a are small at the beginning of the stroke of the piston 8, the piston 8 starts at a low speed, and the cross-sectional areas of these grooves gradually increase with the stroke of the piston 8, so that the speed becomes smooth. To increase. When the piston 8 passes the middle position of the stroke, the cross-sectional areas of the grooves 5a and 11b gradually decrease, so that the speed of the piston 8 smoothly decreases and stops at the left end stroke end. When the switching valve is switched and compressed air is supplied from the port 16 and discharged from the port 15, the piston 8 and the rod 9 move to the right in the figure. Since the speed change of the piston 8 in this case is the same as that in the case of left movement, detailed description will be omitted.

In the above embodiment, the piston 8 can be started and stopped at a low speed, but the speed in the middle of the stroke is smoothly increased, so that the stroke time of the piston can be shortened. Further, since a complicated control circuit is not required, the speed control mechanism can be made inexpensive. Further, the ventilation mandrel 5 is loosely inserted into the hollow portion 10 provided in the piston rod 9, and the ring 12 attached to the hollow portion 10 and the axial groove 5a formed in the ventilation mandrel 5 allow the head side pressure chamber 17 to be closed. Since the air supply / exhaust is controlled, the axial length of the fluid pressure cylinder can be greatly shortened.

[0012]

[Effect of the device]

 In the fluid pressure cylinder with speed control mechanism of the present invention, a groove having an axial length substantially equal to the stroke of the piston and having a smoothly changing cross-sectional area is provided on the outer peripheral surface of the expanded portion of the vent rod and the piston rod. By providing the ring that abuts the outer peripheral surface of the hollow portion of the piston rod and the concave portion of the cylinder, the stroke speed of the piston can be changed smoothly and the stroke time can be shortened. Further, since the ventilation mandrel is loosely inserted in the hollow portion provided on the head side of the piston rod, the axial length of the fluid pressure cylinder can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an embodiment.

FIG. 2 is an enlarged cross-sectional view of a main part on the head side.

FIG. 3 is an enlarged cross-sectional view of a main part on a rod side.

FIG. 4 is an enlarged sectional view of a ventilation mandrel.

[Explanation of symbols]

 1 Cylinder 3 Head Cover 4 Rod Cover 5 Vent Mandrel 5a, 11a Groove 6 Recessed 8 Piston 9 Piston Rod 10 Hollow Part 11 Expanded Part 12, 13 Ring 15, 16 Port 17, 18 Pressure Chamber

Claims (3)

[Scope of utility model registration request] 1. A cylinder, a piston that slides in the cylinder, and a piston rod are provided, and pressure fluid is supplied to and discharged from a pair of pressure chambers defined by the piston from a pair of ports,
In a fluid pressure cylinder that reciprocates a piston and a piston rod, the head cover of the cylinder has a hollow ventilation mandrel whose one end communicates with a port on the head side, and the rod cover communicates with the port on the rod side to generate pressure on the rod side. The piston rod is provided with a hollow portion that is opened into the pressure chamber on the head side and in which the ventilation mandrel is loosely inserted; and the rod-side expanded portion that is loosely inserted into the recessed portion, The ventilation mandrel and the expanded diameter portion are provided with a groove on the outer peripheral surface having an axial length substantially equal to the stroke of the piston and having a smoothly changing cross-sectional area, and the hollow portion and the concave portion are provided at the opening portion to the pressure chamber. A fluid pressure cylinder with a speed control mechanism, comprising: a ventilation mandrel and a ring that comes into contact with the outer peripheral surface of the expanded diameter portion. 2. The fluid pressure cylinder with a speed control mechanism according to claim 1, wherein the cross-sectional area of the groove is gradually increased from both ends toward the center. 3. The fluid pressure cylinder with a speed control mechanism according to claim 2, wherein the cross-sectional area of the groove is changed in a sinusoidal shape.