KR20210049935A - Hydraulic cylinder - Google Patents

Abstract

In the fluid pressure cylinder 10 in which the actuating piston 20 and the increasing piston 22 are installed in a tandem manner with a partition wall 26, a high-pressure fluid is sealed in two pressure chambers adjacent to each other in the axial direction. In the operation process, the high-pressure fluid can be communicated between the pressure chambers enclosed with the high-pressure fluid. Then, when the actuating piston 20 moves to the end side, communication of the fluid between the two pressure chambers is prevented by the increase force switching mechanism 33, and the high-pressure fluid in the pressure chamber on one side is exhausted.

Description

Hydraulic cylinder

The present invention relates to a fluid pressure cylinder.

BACKGROUND ART In a working machine such as a clamp device or a locking device, there is a case where a large driving force is not usually required in the whole of the working process, and a large driving force is required in the latter half of the working process. For this reason, as a fluid pressure cylinder used in such a working machine, there has been proposed a type of fluid pressure cylinder with an increasing force mechanism in which the thrust at the latter half of the forward stroke of the piston rod is increased by a force increasing mechanism.

For example, in the fluid pressure cylinder of Japanese Unexamined Patent Application Publication No. 2018-17269, a piston for increasing force is provided as an increasing force mechanism, and the piston for increasing force is locked to the piston rod in the middle of the stroke, thereby increasing the thrust.

In the fluid pressure cylinder with an increase mechanism, there is a demand for a new reduction in the amount of consumption of the working fluid so as to reduce the amount of energy consumption.

Accordingly, an object of the present invention is to provide a fluid pressure cylinder with an increasing force function capable of reducing the consumption amount of the working fluid without complicating the structure.

An aspect of the present invention is a cylinder body having a sliding hole extending in the axial direction, a partition wall dividing the sliding hole into an operation cylinder chamber on the head side and an increase cylinder chamber on the end side, and the operation cylinder disposed in the operation cylinder chamber. An operating piston that divides the chamber into a first pressure chamber on the head side and a second pressure chamber on the end side, and is disposed in the increase cylinder chamber to divide the increase cylinder chamber into a third pressure chamber on the head side and a fourth pressure chamber on the end side. An increase piston, and a piston rod connected to the working piston and the increasing piston and extending toward the end through the partition wall, wherein the first pressure chamber, the second pressure chamber, the third pressure chamber, and the fourth pressure chamber In the middle, while the high-pressure fluid is sealed in the two adjacent pressure chambers, while the operating piston is positioned at the head side rather than a predetermined position, communication of the high-pressure fluid between the two pressure chambers is allowed, while the operating piston When it is moved to the end side from this predetermined position, the communication of the high-pressure fluid between the two pressure chambers is prevented, and further comprising an increase power conversion mechanism for exhausting the high-pressure fluid from one of the two pressure chambers. , In the fluid pressure cylinder.

According to the fluid pressure cylinder according to the present invention, among the first to fourth pressure chambers, the high pressure fluid is sealed in two adjacent pressure chambers. When the working piston is located on the head side rather than the predetermined position, it allows communication of high-pressure fluid between two adjacent pressure chambers. In this case, there is no pressure difference between the two adjacent pressure chambers, and the thrust does not increase. On the other hand, when the working piston moves near the end of the stroke, communication between two adjacent pressure chambers is prevented, and the high-pressure fluid in one pressure chamber is exhausted. Thereby, a thrust corresponding to the pressure difference between two adjacent pressure chambers is generated, and the thrust of the piston rod can be increased in the vicinity of the stroke end. Since the high-pressure fluid is exhausted from the end of the stroke, the amount of fluid used to increase the thrust can be suppressed.

1 is a cross-sectional view of a fluid pressure cylinder according to a first embodiment, and a partially enlarged view in the drawing is an enlarged cross-sectional view of a third check valve 56.
2 is a side view of the end side of the fluid pressure cylinder of FIG. 1.
Fig. 3 is an enlarged sectional view of the fluid pressure cylinder of Fig. 1 in the vicinity of the partition wall, and Fig. 3B is an enlarged sectional view in a state in which the working piston approaches the partition wall of Fig. 3A.
Fig. 4A is a fluid circuit diagram showing a connection state in an operation step of the fluid pressure cylinder according to the embodiment, and Fig. 4B is a fluid circuit diagram showing a connection state in a return step of the fluid pressure cylinder in Fig. 4A.
5 is a cross-sectional view of the fluid pressure cylinder of FIG. 1 in an operation step.
6 is a cross-sectional view of the fluid pressure cylinder of FIG. 1 in a step of increasing the pressure.
Fig. 7 is a cross-sectional view (Fig. 1) in a return step of the fluid pressure cylinder of Fig. 1.
Fig. 8 is a cross-sectional view (Fig. 2) in a return step of the fluid pressure cylinder of Fig. 1.
9A is a plan view of the fluid pressure cylinder according to the second embodiment, and FIG. 9B is a side view of the fluid pressure cylinder of FIG. 9A.
10 is a cross-sectional view of the fluid pressure cylinder of FIG. 9A at a stroke start position.
FIG. 11A is a fluid circuit diagram of the driving device of the fluid pressure cylinder of FIG. 9A, showing a connection state of the selector valve at a first position, and FIG. 11B is a connection state of the selector valve of the drive device of FIG. 11A at a second position. It is a fluid circuit diagram shown.
12 is a cross-sectional view in a step of increasing the fluid pressure cylinder of FIG. 9A.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the dimensional ratios in the drawings are exaggerated for convenience of description and may be different from the actual ratios. In this specification, the direction toward the end of the stroke is referred to as "end direction" or "end side", and the starting direction of the stroke is referred to as "head direction" or "head side". In addition, in this specification, "air" means a gaseous working fluid, and is not particularly limited to air.

(First embodiment)

The fluid pressure cylinder 10 according to the present embodiment includes a cylinder body 12 and a drive device 120 as shown in FIGS. 4A and 4B.

The fluid pressure cylinder 10 has a cylinder body 12 extending in the axial direction as shown in FIG. 1. As shown in FIG. 2, the cylinder body 12 can be made into a square shape, and is formed of a metal material, such as an aluminum alloy, for example.

As shown in Fig. 1, a circular sliding hole 12a (cylinder chamber) extending in the axial direction is formed inside the cylinder body 12. The cylinder body 12 is between the head-side body portion 14 provided on the head side, the end-side body portion 16 provided on the end side, and the head-side body portion 14 and the end-side body portion 16. It has a partition wall 26 installed. The head-side body portion 14, the partition wall 26, and the end-side body portion 16 are axially fastened by connecting rods or bolts 16b, as shown in FIG. 2.

As shown in FIG. 1, a circular operating cylinder chamber 14a is formed in the head-side main body 14, and a circular increasing cylinder chamber 16a is formed in the end-side main body 16. Has been. The operating cylinder chamber 14a and the increasing cylinder chamber 16a are formed with the same inner diameter, and constitute the sliding hole 12a of the cylinder body 12. The operating cylinder chamber 14a and the increase cylinder chamber 16a are divided by a partition wall 26.

The actuating piston 20 is arranged in the actuating cylinder chamber 14a, and the increasing piston 22 is arranged in the increasing cylinder chamber 16a. The actuating piston 20 and the increasing piston 22 are connected to a piston rod 18 extending through the partition wall 26 and the cylinder body 12 toward the end.

The head-side body portion 14 is provided with a head-side port 28, a head cover 46, and an actuating piston 20. The head cover 46 is attached to an end portion of the operating cylinder chamber 14a on the head side, and the head side of the operating cylinder chamber 14a is blocked by the head cover 46.

In the vicinity of the head cover 46, a head-side port 28 is formed. The head-side port 28 is formed through the head-side body portion 14. The head-side port 28 is provided in the vicinity of the head-side end portion of the operating cylinder chamber 14a and communicates with the operating cylinder chamber 14a (first pressure chamber 38) through the opening 28a.

The actuating piston 20 is slidably accommodated in the actuating cylinder chamber 14a in the axial direction. An annular packing mounting groove 21a is formed on the outer circumferential surface of the actuating piston 20, and a packing 21 is mounted in the packing mounting groove 21a. The packing 21 is in close contact with the inner circumferential surface of the operating cylinder chamber 14a while being elastically deformed, thereby sealingly dividing the operating cylinder chamber 14a into a first pressure chamber 38 and a second pressure chamber 40. The first pressure chamber 38 is an empty chamber formed between the actuating piston 20 and the head cover 46 and is formed on the head side than the actuating piston 20. Further, the second pressure chamber 40 is an empty chamber formed between the actuating piston 20 and the partition wall 26, and is formed at the end side of the actuating piston 20. The first pressure chamber 38 communicates with the head side port 28 through the opening 28a.

The actuating piston 20 is connected to the piston rod 18 at the head-side connection portion 18a of the piston rod 18, and is configured to be displaced integrally with the piston rod 18.

On the other hand, in the end-side main body 16, an increase piston 22, a rod cover 48, an end-side port 30, and an auxiliary passage 76 are provided.

The increase piston 22 is disposed so as to be slidable in the axial direction in the increase cylinder chamber 16a of the end-side main body 16. On the outer circumferential surface of the increasing piston 22, an annular packing mounting groove 23a and an annular magnet mounting groove 24a are provided. A ring-shaped packing 23 made of an elastic material such as rubber is mounted in the packing mounting groove 23a. Further, a magnet 24 in a circular ring shape is mounted in the magnet mounting groove 24a. Further, a wear ring (not shown) is attached to the outer periphery of the magnet 24.

The increasing piston 22 airtightly divides the increasing cylinder chamber 16a into a third pressure chamber 42 and a fourth pressure chamber 44 through a packing 23. The third pressure chamber 42 is an empty chamber on the head side of the increase piston 22 and is formed between the increase piston 22 and the partition wall 26. Further, the fourth pressure chamber 44 is an empty chamber on the end side of the increasing piston 22 and is formed between the increasing piston 22 and the rod cover 48. The fourth pressure chamber 44 is in communication with the end-side port 30.

Further, a ring-shaped damper mounting groove 25a is formed on the end surface of the head side of the increase piston 22, and the damper 25 is attached to the damper mounting groove 25a. The damper 25 is made of an elastic material such as rubber, and is configured to prevent a collision between the increasing piston 22 and the partition wall 26. The increasing piston 22 is connected to the piston mounting portion 18b provided in the central portion of the piston rod 18, and is configured to be integrally displaced with the piston rod 18 in the axial direction.

The rod cover 48 is attached to the end side of the increase cylinder chamber 16a. The rod cover 48 is formed in a disk shape, and an annular packing mounting groove 48d is formed in its outer circumferential portion. A circular ring-shaped packing 48c is attached to the packing mounting groove 48d. The packing 48c hermetically seals the packing mounting groove 48d.

In the vicinity of the center of the rod cover 48 in the radial direction, an insertion hole 48a for inserting the piston rod 18 is formed extending in the axial direction. A rod packing 48b is provided in the insertion hole 48a to prevent leakage of air along the piston rod 18. Further, a ring-shaped damper mounting groove 47a is formed on the end surface of the rod cover 48 on the head side, and the damper 47 is attached to the damper mounting groove 47a. The damper 47 is made of an elastic member formed in a circular ring shape and protrudes toward the increase cylinder chamber 16a to prevent collision between the increase piston 22 and the rod cover 48.

Further, on the end side of the rod cover 48, a drop-out prevention clip 49 for fixing the rod cover 48 is attached. The anti-fall clip 49 is a plate member engaged with an engaging groove 49a formed along the inner circumferential surface of the end-side main body 16. The anti-fall clip 49 is a ring-shaped plate member in which a part of the circumferential direction is cut, and is engaged with the engaging groove 49a by the elastic restoring force, and abuts the end surface of the end side of the rod cover 48 to the rod cover (48) is prevented from dropping out.

The end-side port 30 is formed in the vicinity of the end-side end portion of the end-side main body 16. The end-side port 30 is formed to penetrate from the outer periphery of the end-side main body 16 toward the increase cylinder chamber 16a, and at the end side of the increase cylinder chamber 16a, a fourth pressure chamber ( 44).

The auxiliary flow path 76 is a flow path formed inside the end-side main body 16 and extends in the axial direction. The auxiliary passage 76 has one end communicating with the end-side port 30, and the other end communicating with the adjustment port 32 of the partition wall 26 described later.

The third check valve 56 is installed in the middle of the auxiliary flow path 76. The third check valve 56 has a cavity 56a having a larger diameter than the auxiliary flow path 76 and a valve body 56b inserted into the cavity 56a. As a member formed in the shape of a cylindrical cup with a bottom, the bottom 56c is disposed on the downstream side in the direction of blocking the flow of air. On the bottom 56c of the valve body 56b, an annular protrusion 56d is formed that abuts against the end surface of the cavity 56a and closes the auxiliary flow path 76 communicating with the cavity 56a.

Further, a notch 56e is formed on the side of the valve body 56b to allow air to pass therethrough. As for the air flowing from the bottom 56c side, the annular protrusion 56d of the valve body 56b is spaced apart from the end surface of the cavity 56a and is configured to pass air through the cutout 56e. . In addition, with respect to the air in the reverse direction, the portion of the bottom 56c of the valve body 56b receives the pressure of the air, and the annular protrusion 56d abuts the end face of the cavity 56a, and the auxiliary passage 76 ) Is closed to prevent the flow of air.

In addition, in order to facilitate the operation of the third check valve 56, a pressing member such as a spring that presses the annular protrusion 56d of the valve body 56b in a direction contacting the end surface of the cavity 56a ( 56f) can also be installed in the cavity 56a. In addition, the first check valve 52 and the second check valve 54 described later have the same structure as the third check valve 56.

The partition wall 26 is provided with the plate-shaped main body 60 as shown in FIG. 3A. In the main body 60, a first connecting portion 63 protruding toward the head and inserted into the operating cylinder chamber 14a, and a second connecting portion 64 protruding toward the end and inserted into the increasing cylinder chamber 16a are formed. . The first connecting portion 63 is formed in a cylindrical shape having an outer diameter substantially equal to the inner diameter of the operating cylinder chamber 14a, and a packing 63a is attached to the outer peripheral portion thereof. Further, the second connecting portion 64 is formed in a cylindrical shape having an outer diameter substantially equal to the inner diameter of the increasing cylinder chamber 16a, and a packing 64a is attached to the outer circumferential portion thereof. The packing 63a seals the gap between the operating cylinder chamber 14a and the first connecting portion 63, and the packing 64a seals the gap between the increasing cylinder chamber 16a and the second connecting portion 64.

In the vicinity of the center of the partition wall 26 in the radial direction, a through portion 61 for inserting the piston rod 18 is formed to extend in the axial direction. The through part 61 is provided with a packing 62 to prevent leakage of air along the piston rod 18.

Further, the partition wall 26 comprises a communication passage 34 constituting the increase switching mechanism 33, a communication switching valve 35 provided in the communication passage 34, an exhaust passage 36, and an exhaust passage ( It has an exhaust selector valve 37 installed in 36).

The communication passage 34 is a passage for flowing air between the second pressure chamber 40 and the third pressure chamber 42, and a through hole 65 penetrating the partition wall 26 in the axial direction, and It is composed of an inner flow path 35e of the communication switching pin 35a inserted in the through hole 65 and a hole portion 66b of the stopper 66.

The through hole 65 is formed by penetrating the partition wall 26 in the axial direction, and inserting a large-diameter portion 65a formed on the head side, a small-diameter portion 65b formed in the center of the axial direction, and a stopper formed on the end side. It has a hole 65c. The large-diameter portion 65a and the stopper insertion hole 65c are formed with an inner diameter larger than that of the small-diameter portion 65b. Communication switching pins 35a are inserted into the large-diameter portion 65a and the small-diameter portion 65b. The stopper 66 is inserted into the stopper insertion hole 65c. The stopper 66 is connected to the end side of the communication switching pin 35a of the communication switching valve 35, and is integrally displaced with the communication switching pin 35a. Further, by stopping the stopper 66 in the stopper insertion hole 65c, the movement of the communication switching pin 35a toward the head is restricted.

The communication switching valve 35 is configured with a communication switching pin 35a. The communication switching pin 35a has a closing portion 35c formed on the head side and a rod portion 35d extending in the axial direction toward the end side. The rod portion 35d is formed to have a diameter substantially the same as the inner diameter of the small-diameter portion 65b of the through hole 65, and is inserted into the small-diameter portion 65b so as to be slidable in the axial direction. The closing portion 35c is formed to have a diameter substantially the same as the inner diameter of the large-diameter portion 65a of the through hole 65, and is configured to be able to be inserted into the large-diameter portion 65a. A ring-shaped packing 35b is attached to the outer periphery of the closing portion 35c. The packing 35b is configured to seal the communication passage 34 in close contact with the large-diameter portion 65a when the closing portion 35c is pushed into the large-diameter portion 65a.

Further, a pressing member 35f is attached to the end side of the closing portion 35c of the communication switching pin 35a. The pressing member 35f is made of, for example, a spring, and is inserted into a gap between the large-diameter portion 65a and the communication switching pin 35a. The pressing member 35f presses the communication switching pin 35a toward the head, so that the closing portion 35c is separated from the through hole 65 and protrudes toward the second pressure chamber 40. That is, the communication switching valve 35 is configured so as not to interfere with the communication of the communication passage 34 in a state in which the communication switching pin 35a is not pressed toward the head by the operating piston 20.

On the other hand, the exhaust passage 36 is opened from the end surface of the partition wall 26 on the side of the first connection part 63, and extends in the axial direction, the detection pin receiving hole 67, the detection pin receiving hole 67, and the adjustment port. It has a connection passage (71) in communication with (32). Among them, the detection pin receiving hole 67 has a large diameter portion 67a formed on the head side, a small diameter portion 67b formed on the end side of the large diameter portion 67a, and a stopper insertion hole 67c. The stopper 68 is inserted into the stopper insertion hole 67c. The stopper 68 is connected to the detection pin 37a and is integrally displaced with the detection pin 37a. The stopper 68 is stopped at the end of the small-diameter portion 67b on the end side, thereby restricting the range of movement of the detection pin 37a toward the head side.

The connection passage 71 communicates with the detection pin receiving hole 67 in the opening 71a formed on the side of the small diameter portion 67b. The small-diameter portion 67b has an enlarged diameter in a predetermined range around the opening 71a, and a gap is formed between it and the exhaust selector valve 37.

The connection passage 71 is provided with a first check valve 52 that allows air to pass only in the direction from the opening 71a to the adjustment port 32. The first check valve 52 is disposed in a direction allowing exhaust of air from the second pressure chamber 40.

The exhaust switching valve 37 has a detection pin 37a. The detection pin 37a includes a pin body portion 37b extending cylindrically in the axial direction, and a flange portion 37c extending radially outward at the head-side end portion of the pin body portion 37b. The flange portion 37c is formed to have a diameter slightly smaller than the inner diameter of the large-diameter portion 67a, and is configured to be able to be inserted into the large-diameter portion 67a. A pressing member 37f made of a spring or the like is attached to the large-diameter portion 67a. The pressing member 37f is configured to come into contact with the flange portion 37c and press the detection pin 37a toward the head so that the flange portion 37c protrudes toward the second pressure chamber 40.

The pin body portion 37b is formed to have a diameter slightly smaller than the inner diameter of the small-diameter portion 67b, and is configured to be slidable in the axial direction along the small-diameter portion 67b. A packing 37d and a packing 37e are arranged at intervals in the axial direction on the outer periphery of the pin body part 37b. The packing 37d and the packing 37e are in close contact with the small-diameter portion 67b when the detection pin 37a is not pressed against the actuating piston 20, and the detection pin receiving hole 67 and the connection passage 71 ) Is placed in a position to block communication. That is, the exhaust selector valve 37 prevents communication of the exhaust flow path 36 in a state where it is not pressurized by the actuating piston 20.

In the head-side body portion 14 in the vicinity of the adjustment port 32, a replenishment passage 78 and a second check valve 54 are provided. The replenishment passage 78 is in communication with the adjustment port 32 and the second pressure chamber 40. A second check valve 54 is installed in the replenishment passage 78. One end of the second check valve 54 communicates with the adjustment port 32 through the replenishment passage 78. Further, the other end of the second check valve 54 communicates with the second pressure chamber 40 through the supplemental passage 78. The second check valve 54 allows air to pass only in the direction from the adjustment port 32 to the second pressure chamber 40 and prevents the air from passing in the opposite direction. That is, the second check valve 54 is configured to allow the flow of air supplemented to the second pressure chamber 40 and to block air in the opposite direction.

The fluid pressure cylinder 10 of this embodiment is configured as described above, and is driven by the drive device 120 as shown in Fig. 4A.

The drive device 120 includes a fourth check valve 86, a throttle valve 88, a selector valve 102, a high-pressure air supply source (high-pressure fluid supply source) 104, and an exhaust port 106. have. This drive device 120 is configured to supply high-pressure air to the first pressure chamber 38 of the operating cylinder chamber 14a in an operation step. In addition, as shown in FIG. 4B, in the return process, the drive device 120 supplies part of the air accumulated in the first pressure chamber 38 toward the fourth pressure chamber 44, and the second It is configured to supply high-pressure air to the pressure chamber 40.

The switching valve 102 is, for example, a 5-port 2-position valve, and has a first port 102a to a fifth port 102e, and a first position (see Fig. 4A) and a second position (see Fig. 4B). ) Can be switched. 4A and 4B, the first port 102a is connected to the head side port 28 by a pipe. The second port 102b is connected to the adjustment port 32 by piping. The third port 102c is connected to the exhaust port 106 by a pipe. The fourth port 102d is connected to the high-pressure air supply source 104 by a pipe. The fifth port 102e is connected to the exhaust port 106 through the throttle valve 88 by piping, and is connected to the end-side port 30 through the fourth check valve 86.

4A, when the selector valve 102 is in the first position, the first port 102a and the fourth port 102d are connected, and the second port 102b and the third port (102c) is connected.

In addition, as shown in FIG. 4B, when the selector valve 102 is in the second position, the first port 102a and the fifth port 102e are connected, and the second port 102b and the fourth port are connected. Port 102d is connected. The switching valve 102 is switched to a first position and a second position by a pilot pressure from the high-pressure air supply source 104 or an electromagnetic valve.

The fourth check valve 86 allows the flow of air from the head side port 28 to the end side port 30 when the selector valve 102 is in the second position, and the end side port 30 The flow of air from the port 28 to the head side is prevented.

The throttling valve 88 is installed to limit the amount of air in the first pressure chamber 38 exhausted from the exhaust port 106, and is configured as a variable throttling valve that can change the passage area to adjust the exhaust flow rate. have.

In addition, an air tank is provided in the middle of the pipe connecting the fourth check valve 86 and the fourth pressure chamber 44, and air supplied to the end-side port 30 from the head-side port 28 in the return process. Can also be made to accumulate. By providing the air tank, it is possible to accumulate a sufficient amount of air to fill the fourth pressure chamber 44 during the return operation, thereby stabilizing the return operation. In this case, the capacity of the air tank can be set to about half of the maximum capacity of the first pressure chamber 38, for example. When the capacity of the piping can be sufficiently secured, an air tank is unnecessary.

The fluid pressure cylinder 10 and the drive device 120 are configured as described above, and the operation and operation thereof will be described below.

(Startup process)

In the starting process, the second pressure chamber 40 and the third pressure chamber 42 are filled with high-pressure air prior to the start of use of the fluid pressure cylinder 10. In addition, high-pressure air is air with a pressure higher than atmospheric pressure. Here, the fluid pressure cylinder 10 is set to the start position of the stroke as shown in FIG. 1. Further, the selector valve 102 of the drive device 120 is set to the second position (see Fig. 4B). Thereby, the high-pressure air supply source 104 is connected to the adjustment port 32. As shown in FIG. 4B, high-pressure air from the high-pressure air supply source 104 is introduced into the second pressure chamber 40 through the second check valve 54. In addition, high-pressure air introduced into the second pressure chamber 40 is also introduced into the third pressure chamber 42 through the communication passage 34. As a result, the second pressure chamber 40 and the third pressure chamber 42 are filled with high-pressure air. The starting process only needs to be performed once before the first stroke of the fluid pressure cylinder 10.

(Operation process)

As shown in Fig. 4A, the operating process of the fluid pressure cylinder 10 is performed with the switching valve 102 of the drive device 120 at the first position. High-pressure air from the high-pressure air supply source 104 is supplied to the head-side port 28 through the first port 102a of the switching valve 102. The fourth check valve 86 is connected to the fifth port 102e side, and high-pressure air does not flow to the fourth check valve 86 side. The 4th pressure chamber 44 is connected to the exhaust port 106 through the 3rd check valve 56, the adjustment port 32, and the 2nd port 102b.

As shown in FIG. 5, in the operation process, high-pressure air from the high-pressure air supply source 104 flows into the first pressure chamber 38, as shown by arrow B. The force acting on the working piston by the high-pressure air in the second pressure chamber 40 and the force acting on the increasing piston 22 by the high-pressure air charged in the third pressure chamber 42 are equal in magnitude and in opposite directions. Because it is balanced, it does not contribute to thrust. Accordingly, in the piston rod 18, a thrust corresponding to the pressure difference between the first pressure chamber 38 adjacent to the actuating piston 20 and the fourth pressure chamber 44 adjacent to the increasing piston 22 is generated. And, the piston rod 18 strokes toward the end side.

With the stroke of the working piston 20, the fluid pressure cylinder 10 is supplied with high-pressure air in an amount equal to the volume of the first pressure chamber 38 from the high-pressure air supply source 104 (see Fig. 4A). In accordance with the strokes of the actuating piston 20 and the increasing piston 22, the high-pressure air in the second pressure chamber 40 moves to the third pressure chamber 42 through the communication passage 34. Between the operating processes, the pressure of the high-pressure air accumulated in the second pressure chamber 40 and the third pressure chamber 42 is kept constant. Further, the air in the fourth pressure chamber 44 is exhausted from the fourth pressure chamber 44 along with the stroke of the increasing piston 22. In this case, the air in the fourth pressure chamber 44 passes through the adjustment port 32 through the third check valve 56 and the auxiliary flow path 76, and, as shown in FIG. 4A, the selector valve 102 ) Is exhausted from the exhaust port 106 through the second port 102b.

(Intensification process)

6, with the stroke of the operating piston 20, the communication switching pin 35a (see FIG. 3B) of the communication switching valve 35 is pressurized toward the end, and the exhaust switching valve 37 The detection pin 37a (see Fig. 3B) is also pressed toward the end side.

As a result, as shown in FIG. 3B, the closing portion 35c of the communication switching pin 35a is inserted into the large diameter portion 65a of the through hole 65. Then, the packing 35b of the closing portion 35c closes the communication passage 34 by sealing the gap between the large-diameter portion 65a and the closing portion 35c. That is, the flow of air between the second pressure chamber 40 and the third pressure chamber 42 through the communication passage 34 is prevented by the communication switching valve 35.

In addition, when the detection pin 37a of the exhaust selector valve 37 is displaced toward the end side, the packing 37d sealing the gap between the detection pin 37a and the detection pin receiving hole 67 is concave. It moves to the recessed opening 71a. As a result, the exhaust flow path 36 is opened, and the adjustment port 32 and the second pressure chamber 40 communicate with each other through the exhaust flow path 36. The high-pressure air accumulated in the second pressure chamber 40 is exhausted from the exhaust port 106 through the first check valve 52 and the adjustment port 32. As a result, the internal pressure of the second pressure chamber 40 decreases, and a thrust force is generated in the operating piston 20 according to the difference in the internal pressure between the second pressure chamber 40 and the first pressure chamber 38.

In addition, thrust is generated in the increase piston 22 according to a pressure difference between the pressure of the high-pressure air accumulated in the third pressure chamber 42 and the pressure of the fourth pressure chamber 44. Thereby, the fluid pressure cylinder 10 can increase thrust in the vicinity of the stroke end. The increase in thrust in the fluid pressure cylinder 10 is generated by exhausting the high pressure air from the second pressure chamber 40 in the range in which the communication switching valve 35 and the exhaust switching valve 37 operate.

(Return process)

As shown in Fig. 4B, the return process of the fluid pressure cylinder 10 is performed with the selector valve 102 of the drive device 120 at the second position. High-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32 through the second port 102b of the switching valve 102. The first port 102a of the switching valve 102 is connected to the fifth port 102e, and the head-side port 28 is connected to the end-side port 30 through the fourth check valve 86. Further, the head-side port 28 is connected to the exhaust port 106 through a throttle valve 88. As a result, part of the air accumulated in the first pressure chamber 38 is supplied to the fourth pressure chamber 44 through the fourth check valve 86 side. Further, a part of the remaining air accumulated in the first pressure chamber 38 is exhausted from the exhaust port 106.

As shown in Fig. 7, in the return process, high-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32 of the fluid pressure cylinder 10, as shown by arrow B. The high-pressure air supplied to the adjustment port 32 flows into the second pressure chamber 40 through the supplementary flow path 78 and the second check valve 54. The volume of high-pressure air supplied to the second pressure chamber 40 is the same as the amount of high-pressure air exhausted from the second pressure chamber 40 in the increase process. That is, the high-pressure air required for the increase process is replenished during the return process. The amount of high-pressure air supplied at that time is less than the amount of high-pressure air required for the stroke of the working piston 20, and it is sufficient to add a small amount of high-pressure air.

In the return process, since the internal pressure of the second pressure chamber 40 becomes the same as the internal pressure of the third pressure chamber 42, the force exerted by the second pressure chamber 40 on the actuating piston 20 and the third pressure The forces exerted by the seal 42 on the increasing force piston 22 are balanced and cancel each other out.

Meanwhile, a part of the high-pressure air exhausted from the first pressure chamber 38 flows into the fourth pressure chamber 44 as shown by arrow A. As the air exhausting from the first pressure chamber 38 proceeds, the pressure difference between the fourth pressure chamber 44 and the first pressure chamber 38 increases, and the actuating piston 20 and the increasing piston 22 And the piston rod 18 starts moving toward the head. Accordingly, the communication switching valve 35 returns to its original position, and the second pressure chamber 40 and the third pressure chamber 42 communicate with each other through the communication passage 34. Further, the exhaust selector valve 37 seals the exhaust passage 36 to prevent communication between the adjustment port 32 and the second pressure chamber 40.

Thereafter, as shown in FIG. 8, as air flows into the fourth pressure chamber 44, the exhaust of the first pressure chamber 38 proceeds, and the actuating piston 20 and the increasing force piston 22 It returns to the start position, and the return process is completed.

The fluid pressure cylinder 10 according to the present embodiment has the following effects.

In the fluid pressure cylinder 10, the fluid pressure cylinder 10 includes a communication passage 34 communicating with the second pressure chamber 40 and the third pressure chamber 42 as an increase force switching mechanism 33, 2 While the exhaust flow path 36 in communication with the pressure chamber 40 and the operating piston 20 are located on the head side rather than a predetermined position, the communication flow path 34 is opened and the operating piston 20 When moving to the end side, the communication switching valve 35 closes the communication flow path 34, and while the operating piston 20 is positioned on the head side rather than a predetermined position, the exhaust flow path 36 is closed and the operating piston 20 When) is moved to the end side from the predetermined position, the exhaust flow path 36 is opened to exhaust the high-pressure fluid in the second pressure chamber 40, and an exhaust switching valve 37 is provided. Thereby, in the vicinity of the stroke end, the second pressure chamber 40 and the third pressure chamber 42 are separated, and while maintaining the high-pressure air in the third pressure chamber 42, the second pressure chamber 40 is High-pressure air can be exhausted. Thereby, in addition to the thrust of the actuating piston 20, the thrust of the increasing piston 22 is added, and the thrust can be increased in the latter half of the stroke.

In the fluid pressure cylinder 10, the partition wall 26 has an adjustment port 32, and the exhaust passage 36 may exhaust the high pressure fluid in the second pressure chamber 40 through the adjustment port 32. have.

In the fluid pressure cylinder 10, the increase switching mechanism 33 may cause the exhaust switching valve 37 to open the exhaust passage 36 after the communication switching valve 35 closes the communication passage 34. Thereby, it is possible to prevent the outflow of high-pressure air from the third pressure chamber 42 through the second pressure chamber 40 and suppress the amount of high-pressure air used.

In the fluid pressure cylinder 10, the communication switching valve 35 has a communication switching pin 35a having one end protruding toward the second pressure chamber 40 and the other end inserted into the communication passage 34, and a communication switching pin The communication passage 34 can be closed by the 35a being pressed against the actuating piston 20 and displaced toward the end. Thereby, the communication switching valve 35 can be operated using the stroke operation of the actuating piston 20, and the device configuration can be simplified.

In the fluid pressure cylinder 10, the exhaust selector valve 37 seals the exhaust passage 36 and has a detection pin 37a having one end protruding into the second pressure chamber 40, and the detection pin It can be configured so that the sealing of the exhaust flow path 36 is released by the pressure 37a being pressed against the actuating piston 20 and displaced toward the end side. Thereby, the second pressure chamber 40 can be exhausted through the exhaust flow path 36 using the stroke operation of the actuating piston 20, and the device configuration is simplified.

In the fluid pressure cylinder 10, a first check valve that passes air through the exhaust passage 36 only in a direction from the second pressure chamber 40 toward the adjustment port 32 and blocks air in the opposite direction. (52) may have been installed. Thereby, it is possible to prevent malfunction of the exhaust selector valve 37 in the return process.

In the fluid pressure cylinder 10, the adjustment port 32 and the second pressure chamber 40 are further provided with a supplemental flow path 78, and the supplemental flow path 78 is provided with a second pressure chamber from the adjustment port 32. A second check valve 54 that allows air to pass only in a direction toward 40 and blocks air in the opposite direction may be provided. By providing the second check valve 54, it is possible to suppress the inflow of excessive high-pressure air into the second pressure chamber 40 in the return process.

In the above-described fluid pressure cylinder 10, it may further have an auxiliary flow path 76 communicating with the fourth pressure chamber 44 and the adjustment port 32. Thereby, in the operation process and the increase process, the air in the 4th pressure chamber 44 can be exhausted through the adjustment port 32. As shown in FIG.

In the above-described fluid pressure cylinder 10, only air in the direction from the fourth pressure chamber 44 to the adjustment port 32 is passed through the auxiliary flow path 76, and a third check for blocking air in the opposite direction. Valve 56 may be installed. Thereby, when supplying high-pressure air to the adjustment port 32 in the return process, it is possible to prevent the high-pressure air from flowing into the fourth pressure chamber 44, thereby suppressing the consumption amount of high-pressure air.

In the hydraulic cylinder 10, further comprising a driving device 120 connected to the first pressure chamber 38, the second pressure chamber 40, and the fourth pressure chamber 44 of the fluid pressure cylinder 10. And, the driving device 120 has a selector valve 102, a high-pressure air supply source 104, an exhaust port 106, and a fourth check valve 86, and is at the first position of the selector valve 102. In addition, the first pressure chamber 38 communicates with the high-pressure air supply source 104, and the fourth pressure chamber 44 and the adjustment port 32 (intensity switch mechanism 33) communicate with the exhaust port 106. In the second position of the switching valve 102, the first pressure chamber 38 communicates with the fourth pressure chamber 44 through the fourth check valve 86, and the first pressure chamber 38 It can be configured to communicate with the exhaust port 106 and to communicate with the high-pressure air supply source 104 through the adjustment port 32 and the second pressure chamber 40. Thereby, in the return process, since the air accumulated in the first pressure chamber 38 can be supplied to the fourth pressure chamber 44, the consumption amount of high-pressure air can be suppressed.

In the fluid pressure cylinder 10 described above, a throttling valve 88 can be provided between the first pressure chamber 38 and the exhaust port 106. Thereby, the amount of air supplied to the 4th pressure chamber 44 can be adjusted suitably.

(2nd embodiment)

As shown in FIG. 9A, the fluid pressure cylinder 10a of this embodiment has a head-side main body part 14A and an end-side main body part 16A. In this embodiment, the high-pressure fluid is sealed in the end-side main body 16A. Further, in order to further increase the thrust at the stroke end, the size (width and height) of the end-side body portion 16A is made larger than the size of the head-side body portion 14A.

As shown in Fig. 9B, the head-side main body portion 14A and the end-side main body portion 16A have a rectangular cross section. The head-side body portion 14A and the end-side body portion 16A are axially connected by a connecting rod or bolt.

As shown in Fig. 10, the cylinder body 12a of the fluid pressure cylinder 10a includes a head-side body portion 14A and an end-side body portion 16A, and both are axially formed through the partition wall portion 126. It is connected in the direction. The head-side main body portion 14A is provided with a head-side port 28A and an end-side port 30A. In the end-side body portion 16A, an adjustment port 32A is provided in the vicinity of the end-side end portion.

Further, in the vicinity of the outer periphery of the partition wall portion 126, a storage air exhaust port 162 for discharging the high-pressure air enclosed in the increase cylinder chamber 116a is formed. The saving air exhaust port 162 is in communication with the third pressure chamber 42 through an adjustment valve 160. The stored air exhaust port 162 discharges the high-pressure air stored in the increase cylinder chamber 116a during maintenance of the fluid pressure cylinder 10a, or introduces high-pressure air into the increase cylinder chamber 116a when starting. It is used to do.

In the central portion of the partition wall portion 126, an insertion hole 126c through which the piston rod 18A is slidably inserted is formed. The insertion hole 126c is provided with a packing 118 for preventing leakage of fluid in the axial direction. The partition wall portion 126 is provided with a head-side connecting portion 126a that extends toward the head and is inserted into the operating cylinder chamber 14a. Further, on the end side of the partition wall portion 126, an end-side connection portion 126b inserted into the increase cylinder chamber 116a is provided. To the end-side connecting portion 126b, a ring-shaped buffer member 124 for avoiding a collision with the increasing piston 22A is attached.

The end-side main body 16A has a main body 116. Inside the main body 116, an increase cylinder chamber 116a made of a circular cavity is formed. The increase cylinder chamber 116a extends in the axial direction. In the inside of the cylinder chamber 116a, an increase piston 22A is disposed so as to be slidable in the axial direction. The increase piston 22A is connected to the piston rod 18A. A magnet 24 and a packing 23 are attached to the outer periphery of the increase piston 22A. The increase piston 22A divides the increase cylinder chamber 116a into a third pressure chamber 42 on the head side and a fourth pressure chamber 44 on the end side.

In addition, a communication switching valve 35A for switching the communication state of the high-pressure fluid between the third pressure chamber 42 and the fourth pressure chamber 44 adjacent in the axial direction is installed on the increase piston 22A. Has been. The communication switching valve 35A includes a through hole 122 penetrating the increasing piston 22A in the axial direction, and a communication switching pin 35a inserted into the through hole 122.

The through hole 122 has an end-side diameter expanding portion 122a, a diameter reducing portion 122b, and a head-side diameter expanding portion 122c. The communication switching pin 35a of the communication switching valve 35A is the same as the communication switching pin 35a described with reference to FIG. 3A. In the diameter reduction part 122b, the rod part 35d of the communication switching pin 35a is inserted. Further, on the side of the end-side diameter expanding portion 122a, a closing portion 35c of the communication switching pin 35a is disposed. The communication switching pin 35a protrudes toward the end by the pressing force of the pressing member 35f.

And, through the through hole 122 and the internal flow path (35e) of the communication switching pin (35a), to enable communication of high-pressure air between the third pressure chamber (42) and the fourth pressure chamber (44). Consists of. That is, in this embodiment, a communication passage is constituted by the through hole 122 and the internal passage 35e. Further, the communication switching pin 35a is pressed against the rod cover 48A when the increasing force piston 22A moves to the end side, and the closing portion 35c and the packing 35b of the outer circumferential portion thereof reach the through hole 122. It is inserted and blocks the through hole 122 to prevent communication between the third pressure chamber 42 and the fourth pressure chamber 44.

The rod cover 48A is provided near the end-side end portion of the end-side body portion 16A, and seals the end-side end of the increase cylinder chamber 116a. The rod cover 48A is provided with an exhaust selector valve 37A for switching exhaustion of the high-pressure air from the fourth pressure chamber 44. The exhaust switching valve 37A includes a through hole 139 penetrating through the rod cover 48A in the axial direction, and a detection pin 137 inserted into the through hole 139.

In the through hole 139, the end of the end side is blocked by the lid member 150, and the detection pin 137 is disposed on the head side of the lid member 150. The detection pin 137 is pressed toward the head by a pressing member 140 such as a spring disposed between the cover member 150 and the detection pin 137. Therefore, the tip end of the detection pin 137 on the head side protrudes into the fourth pressure chamber 44.

On the outer peripheral portion of the base end portion 138 of the detection pin 137, an annular packing 141 and a packing 142 are attached to be spaced apart in the axial direction. The packing 141 and the packing 142 seal the gap between the through hole 139 and the detection pin 137. A flow path 143 is provided between the packing 141 and the packing 142. The flow path 143 has an inner side communicating with the through hole 139 and an outer side communicating with the ventilation groove 144. The ventilation groove 144 is an annular groove formed over the entire circumferential direction of the outer peripheral portion of the rod cover 48A, and communicates with the adjustment port 32A. A packing 146 is provided on the head side of the ventilation groove 144, and a packing 148 is provided on the end side. By these packings 146 and 148, the ventilation groove 144 is kept airtight. The adjustment port 32A is capable of communicating with the fourth pressure chamber 44 through the ventilation groove 144, the flow path 143 and the through hole 139. That is, in this embodiment, the through hole 139, the flow path 143, and the ventilation groove 144 constitute an exhaust flow path.

In the state where the detection pin 137 has moved toward the head, the through hole 139 is closed by the packings 141 and 142, and the high-pressure fluid in the fourth pressure chamber 44 is not exhausted. On the other hand, when the force increasing piston 22A moves toward the end side, the detection pin 137 is pressed toward the end side, and the packings 141 and 142 are configured to move toward the end side rather than the flow path 143. When the packings 141 and 142 move to the end side from the flow path 143, the fourth pressure chamber 44 and the adjustment port 32A communicate with each other.

The fluid pressure cylinder 10a of this embodiment configured as described above is driven by the drive device 120A shown in Figs. 11A and 11B.

As shown in Fig. 11A, the driving device 120A includes a fourth check valve 86, a throttle valve 88, a selector valve 102, a high-pressure air supply source 104, and an exhaust port 106. Wow, a fifth check valve 108 is provided. This drive device 120A is configured to supply high-pressure air to the first pressure chamber 38 of the operating cylinder chamber 14a in an operation step. Further, as shown in FIG. 11B, the driving device 120A supplies part of the air accumulated in the first pressure chamber 38 toward the second pressure chamber 40 in the return process, and the fourth pressure It is configured to supply high-pressure air to the seal 44.

The switching valve 102 is, for example, a 5-port 2-position valve, and has a first port 102a to a fifth port 102e, and a first position (see Fig. 11A) and a second position (see Fig. 11B). ) Can be converted. 11A and 11B, the first port 102a is connected to the head side port 28A by a pipe. The second port 102b is connected to the downstream side of the adjustment port 32A and the fifth check valve 108 by piping. The third port 102c is connected to the exhaust port 106 by a pipe. The fourth port 102d is connected to the high-pressure air supply source 104 by a pipe. The fifth port 102e is connected to the exhaust port 106 through the throttle valve 88 through a pipe, and the end-side port 30A and the fifth check valve 108 through the fourth check valve 86. It is connected to the upstream side of ).

11A, when the selector valve 102 is in the first position, the first port 102a and the fourth port 102d are connected, and the second port 102b and the third port (102c) is connected.

In addition, as shown in FIG. 11B, when the selector valve 102 is in the second position, the first port 102a and the fifth port 102e are connected, and the second port 102b and the fourth port 102e are connected. Port 102d is connected. The switching valve 102 is switched to a first position and a second position by a pilot pressure from the high-pressure air supply source 104 or an electromagnetic valve.

When the selector valve 102 is in the second position, the fourth check valve 86 allows the flow of air from the head side port 28A to the end side port 30A, and the end side port 30A The flow of air to the head side port 28A is prevented. Further, the fifth check valve 108 blocks the flow of high-pressure air from the second port 102b to the end-side port 30A when the selector valve 102 is in the second position.

The fluid pressure cylinder 10a and its driving device 120A according to the present embodiment are configured as described above, and the operation thereof will be described below together with the operation.

(Operation process)

As shown in Fig. 11A, the operation step of the fluid pressure cylinder 10a is performed with the selector valve 102 of the drive device 120A at the first position. High-pressure air from the high-pressure air supply source 104 is supplied to the head-side port 28 through the first port 102a of the switching valve 102. The fourth check valve 86 is connected to the fifth port 102e side, and high-pressure air does not flow to the fourth check valve 86 side. The second pressure chamber 40 is connected to the exhaust port 106 through an end-side port 30A and a fifth check valve 108. Further, the adjustment port 32A is connected to the exhaust port 106.

As shown in Fig. 10, in the operation process, high-pressure air from the high-pressure air supply source 104 flows into the first pressure chamber 38 from the head-side port 28A. As a result, thrust toward the end is generated in the working piston 20. As a result, the piston rod 18A strokes toward the end side. Further, since the high-pressure air enclosed in the third pressure chamber 42 and the fourth pressure chamber 44 communicates through the communication switching valve 35A, no thrust is generated in the increasing piston 22A.

With the stroke of the actuating piston 20, high-pressure air equal to the volume of the first pressure chamber 38 is supplied to the fluid pressure cylinder 10a from the high-pressure air supply source 104 (see Fig. 11A). Between the operating processes, the pressure of the high-pressure air accumulated in the second pressure chamber 40 and the third pressure chamber 42 is kept constant. In addition, air in the second pressure chamber 40 is exhausted from the second pressure chamber 40 along with the stroke of the operating piston 20. In this case, the air in the second pressure chamber 40 is exhausted from the exhaust port 106 through the end-side port 30A and the fifth check valve 108, as shown in FIG. 11A.

(Intensification process)

As shown in Fig. 12, with the stroke of the increasing piston 22A, the communication switching pin 35a of the communication switching valve 35A is pressed toward the head, and the detection pin 37a of the exhaust switching valve 37A. ) Is pressed to the end side.

As a result, the closing portion 35c of the communication switching pin 35a is inserted into the through hole 122 to close the through hole 122. As a result, communication of high-pressure air between the third pressure chamber 42 and the fourth pressure chamber 44 is prevented.

In addition, when the detection pin 37a of the exhaust selector valve 37A is displaced toward the end side, the packings 141 and 142 that have sealed the gap between the detection pin 37a and the through hole 139 are passed through the flow path 143 ), and the adjustment port 32A and the fourth pressure chamber 44 communicate with each other. As a result, the high-pressure air accumulated in the fourth pressure chamber 44 is exhausted from the exhaust port 106. That is, while the high-pressure air is stored in the third pressure chamber 42, the internal pressure of the fourth pressure chamber 44 decreases. As a result, thrust according to the difference in internal pressure between the fourth pressure chamber 44 and the third pressure chamber 42 is generated in the increasing piston 22A. Since this thrust is added to the thrust of the actuating piston 20, the thrust of the fluid pressure cylinder 10a increases in the vicinity of the stroke end. In this way, the increase in thrust of the fluid pressure cylinder 10a is generated by exhausting the high-pressure air in the fourth pressure chamber 44 in the range in which the communication switching valve 35A and the exhaust switching valve 37A operate. .

(Return process)

As shown in Fig. 11B, the return process of the fluid pressure cylinder 10a is performed with the selector valve 102 of the drive device 120A at the second position. High-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32A through the second port 102b of the selector valve 102. The first port 102a of the switching valve 102 is connected to the fifth port 102e, and the head-side port 28A is connected to the end-side port 30A through the fourth check valve 86. Further, the head-side port 28A is connected to the exhaust port 106 through a throttle valve 88. As a result, a part of the air accumulated in the first pressure chamber 38 is supplied to the fourth pressure chamber 44 through the fourth check valve 86 side. Further, a part of the remaining air accumulated in the first pressure chamber 38 is exhausted from the exhaust port 106.

In the return process, high-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32A of the fluid pressure cylinder 10a. The high-pressure air supplied to the adjustment port 32A flows into the fourth pressure chamber 44. Thereby, the high-pressure air exhausted in the increase step is replenished. At that time, the amount of high-pressure air to be replenished is less than the amount of high-pressure air required for the stroke of the working piston, and it is good only to add a small amount of high-pressure air.

Meanwhile, a part of the high-pressure air exhausted from the first pressure chamber 38 flows into the second pressure chamber 40. As the air exhausted from the first pressure chamber 38 proceeds, the pressure difference between the fourth pressure chamber 44 and the first pressure chamber 38 increases, and the actuating piston 20 moves toward the head. Then, the actuating piston 20 and the increasing force piston 22A return to the start position of the stroke, and the return process is completed. In this way, since the air required for the return of the working piston 20 is supplied from the first pressure chamber 38, there is no need to supply high-pressure air to the second pressure chamber 40.

The fluid pressure cylinder 10a according to the present embodiment achieves the following effects.

In the fluid pressure cylinder 10a of the present embodiment, a high-pressure fluid is sealed in the third pressure chamber 42 and the fourth pressure chamber 44, and the increasing force switching mechanism 33A is a communication switching valve installed in the increasing force piston 22A. 35A and 37A of exhaust selector valves provided in the rod cover 48A are provided. According to this fluid pressure cylinder 10a, thrust can be increased at the stroke end without providing a complicated locking mechanism. In addition, since a mechanical locking mechanism connecting the piston and the piston rod is unnecessary, it is difficult to cause a non-conformity with respect to an axial impact, and the reliability is excellent.

Further, in the fluid pressure cylinder 10a of the present embodiment, the diameter of the increasing piston 22A can be made larger than the diameter of the actuating piston 20. Therefore, by increasing the diameter of the increase piston 22A, while maintaining the thrust at the stroke end, the diameter of the actuating piston 20 can be reduced, and the consumption amount of high-pressure air can be further reduced.

In the above, although preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and it is needless to say that various modifications can be made within the scope not departing from the spirit of the present invention. none.

That is, in the above embodiment, an example in which the driving devices 120 and 120A of the fluid pressure cylinders 10 and 10A are disposed outside the fluid pressure cylinders 10 and 10A has been shown, but the present invention is limited thereto. It is not. A part or all of the members constituting the driving devices 120 and 120A may be incorporated in the cylinder body 12.

In addition, high-pressure fluid is sealed in the first pressure chamber 38 and the second pressure chamber 40 of the fluid pressure cylinder 10, and an actuating stroke is performed with the increasing piston 22, so that the actuating piston 20 in the increase step is performed. It can also be configured to generate additional thrust from ).

Claims (16)

A cylinder body 12 having a sliding hole 12a extending in the axial direction,
A partition wall 26 that divides the sliding hole into an operation cylinder chamber 14a on the head side and an increase cylinder chamber 16a on the end side,
An actuating piston (20) disposed in the actuating cylinder chamber and dividing the actuating cylinder chamber into a first pressure chamber (38) on the head side and a second pressure chamber (40) on the end side,
An increase piston 22 disposed in the increase cylinder chamber to divide the increase cylinder chamber into a third pressure chamber 42 on the head side and a fourth pressure chamber 44 on the end side,
And a piston rod 18 connected to the working piston and the increasing piston and extending toward the end through the partition wall,
While the high-pressure fluid is sealed in two adjacent pressure chambers among the first pressure chamber, the second pressure chamber, the third pressure chamber, and the fourth pressure chamber,
While the actuating piston is positioned on the head side rather than a predetermined position, communication of the high-pressure fluid is allowed between the two pressure chambers, while when the actuating piston moves toward the end side from the predetermined position, the two pressure chambers Including an increase power conversion mechanism 33 to prevent communication of the high-pressure fluid between the two pressure chambers, and to exhaust the high-pressure fluid in one of the two pressure chambers,
Hydraulic cylinder. The method according to claim 1,
A high-pressure fluid is sealed in the second pressure chamber and the third pressure chamber,
The increase power conversion mechanism,
A communication passage (34) communicating with the second pressure chamber and the third pressure chamber,
An exhaust passage 36 communicating with the second pressure chamber,
A communication switching valve (35) which opens the communication passage while the operating piston is located on the head side rather than a predetermined position, and closes the communication passage when the operation piston moves toward the end side from a predetermined position;
While the actuating piston is positioned on the head side rather than a predetermined position, the exhaust passage is closed, and when the actuating piston moves toward the end side from the predetermined position, the exhaust passage is opened to exhaust the high-pressure fluid from the second pressure chamber. Exhaust switching valve (37)
Fluid pressure cylinder having. The method according to claim 2,
The communication flow path, the exhaust flow path, the communication switching valve, and the exhaust switching valve are a fluid pressure cylinder installed in the partition wall. The method according to claim 1,
A high-pressure fluid is sealed in the third pressure chamber and the fourth pressure chamber,
The increase power conversion mechanism,
A communication passage 35e communicating with the third pressure chamber and the fourth pressure chamber,
An exhaust passage communicating with the fourth pressure chamber,
A communication switching valve that opens the communication passage while the actuating piston is located on the head side than a predetermined position, and closes the communication passage when the actuating piston moves toward the end side from a predetermined position;
While the actuating piston is positioned on the head side rather than a predetermined position, the exhaust passage is closed, and when the actuating piston moves toward the end side from the predetermined position, the exhaust passage is opened to exhaust the high-pressure fluid from the fourth pressure chamber. Exhaust switching valve
Fluid pressure cylinder having. The method of claim 4,
A fluid pressure cylinder in which the communication flow path and the communication switching valve are installed in the increase piston. The method of claim 5,
And a rod cover 48 for sealing an end of the fourth pressure chamber on the end side,
The rod cover is a fluid pressure cylinder including the exhaust flow path and the exhaust switching valve. The method according to claim 2 or 4,
The cylinder body has an adjustment port 32 communicating with the exhaust flow path, and the exhaust flow path is a fluid pressure cylinder for exhausting high-pressure fluid through the adjustment port. The method according to claim 2 or 4,
The increasing force switching mechanism is a fluid pressure cylinder in which the exhaust switching valve opens the exhaust passage after the communication switching valve closes the communication passage. The method according to any one of claims 2 to 8,
The communication switching valve has a communication switching pin (35a) having one end protruding toward either side of the two pressure chambers and the other end inserted into the communication passage, and the communication switching pin accompanying the displacement of the operating piston A fluid pressure cylinder that closes the communication passage by being pressurized in the axial direction. The method according to any one of claims 2 to 8,
The exhaust switching valve has a detection pin 37a whose proximal end is inserted into the exhaust flow path to seal the exhaust flow path and protrudes toward the head, and the detection pin is pressed against the operating piston or the increasing force piston to end A fluid pressure cylinder in which the sealing of the exhaust flow path is released by displacing it to the side. The method according to claim 2 or 3,
A fluid pressure cylinder in which a first check valve 52 is installed in the exhaust passage to allow fluid to pass through only the direction in which the fluid is discharged and to block the fluid in the opposite direction. The method according to claim 2 or 3,
It further has a supplemental passage 78 communicating with the second pressure chamber,
A fluid pressure cylinder in which a second check valve (54) for passing a fluid directed to the second pressure chamber is installed in the supplementary passage. The method of claim 7,
It further has an auxiliary flow path 76 communicating with the fourth pressure chamber and the adjustment port,
A fluid pressure cylinder in which a third check valve (56) is provided in the auxiliary passage to pass only the fluid in a direction from the fourth pressure chamber to the adjustment port and to block the fluid in the reverse direction. The method according to claim 2,
Further comprising a driving device 120 connected to the first pressure chamber, the second pressure chamber and the fourth pressure chamber,
The drive device has a switching valve 102, a high-pressure fluid supply source 104, an exhaust port 106, and a fourth check valve 86,
In the first position of the switching valve, while the first pressure chamber communicates with the high-pressure fluid supply source, the fourth pressure chamber and the increase force switching mechanism communicate with the exhaust port,
In the second position of the switching valve, the first pressure chamber communicates with the fourth pressure chamber through the fourth check valve, and the first pressure chamber communicates with the exhaust port, and the second pressure chamber communicates with the exhaust port. The pressure chamber communicates with the high pressure fluid supply source,
Hydraulic cylinder. The method of claim 4,
Further comprising a driving device (120A) connected to the first pressure chamber, the second pressure chamber and the fourth pressure chamber,
The drive device has a switching valve, a high-pressure fluid supply source, an exhaust port, and a fourth check valve,
In the first position of the switching valve, while the first pressure chamber communicates with the high-pressure fluid supply source, the fourth pressure chamber and the second pressure chamber communicate with the exhaust port,
In the second position of the switching valve, the first pressure chamber communicates with the second pressure chamber through the fourth check valve, and the first pressure chamber communicates with the exhaust port, and the fourth The pressure chamber communicates with the high pressure fluid supply source,
Hydraulic cylinder. The method of claim 14 or 15,
A fluid pressure cylinder in which a throttle valve (88) is installed between the first pressure chamber and the exhaust port.

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