WO2020054322A1

WO2020054322A1 - Hydraulic cylinder

Info

Publication number: WO2020054322A1
Application number: PCT/JP2019/032236
Authority: WO
Inventors: ▲高▼田芳行; 高桑洋二; 門田謙吾; 名倉誠一; 染谷和孝; 風間晶博
Original assignee: Smc株式会社
Priority date: 2018-09-13
Filing date: 2019-08-19
Publication date: 2020-03-19
Also published as: TWI702344B; KR102531495B1; EP3835600B1; CN112689714A; BR112021004709A2; RU2769896C9; KR20210049935A; MX2021002864A; JPWO2020054322A1; RU2769896C1; JP7137163B2; CN112689714B; TW202020318A; EP3835600A1; EP3835600A4

Abstract

In a hydraulic cylinder (10) in which an operation piston (20) and a boosting piston (22) are disposed in tandem with a partition wall (26) provided therebetween, a high-pressure fluid is sealed in two axially adjacent pressure chambers. In an operation step, the high-pressure fluid is prepared so as to be able to flow between the pressure chambers in which the high-pressure fluid is sealed. Next, when the operation piston (20) has moved to an end side, the flow of the fluid between the two pressure chambers is blocked by a boost switching mechanism (33) such that the high-pressure fluid in one of the pressure chambers is discharged.

Description

Fluid pressure cylinder

The present invention relates to a fluid pressure cylinder.

(4) In working machines such as a clamp device and a lock device, usually, a large driving force is not required in the first half of the work process, and a large drive force is required in the second half of the work process. Therefore, as a hydraulic cylinder used in these work machines, a hydraulic cylinder with a booster mechanism has been proposed in which the thrust in the latter half of the forward stroke of the piston rod is increased by the booster mechanism.

For example, in the fluid pressure cylinder disclosed in JP-A-2018-17269, a booster piston is provided as a booster mechanism, and the thrust is increased by locking the booster piston to a piston rod during a stroke.

流体 In a hydraulic cylinder with a booster mechanism, further reduction in the consumption of working fluid is required to reduce energy consumption.

Therefore, an object of the present invention is to provide a hydraulic cylinder with a boosting function that can reduce the consumption of working fluid without complicating the structure.

One aspect of the present invention is a cylinder body in which a sliding hole extending in the axial direction is formed, a partition separating the sliding hole into a working cylinder chamber on a head side, and an intensifying cylinder chamber on an end side, An operating piston disposed in the operating cylinder chamber and dividing the operating cylinder chamber into a first pressure chamber on the head side and a second pressure chamber on the end side; and an operating piston disposed in the boost cylinder chamber and connecting the boost cylinder chamber to the head side. A pressure boosting piston partitioned into a third pressure chamber and a fourth pressure chamber on the end side, and a piston rod connected to the operating piston and the force boosting piston and extending to the end side through the partition wall. 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, and the operating piston is closer to the head than a predetermined position. Second place While the high pressure fluid is allowed to flow between the two pressure chambers, when the working piston moves to the end side from the predetermined position, the high pressure fluid flows between the two pressure chambers. A fluid pressure cylinder includes a boost switching mechanism for preventing conduction and discharging high-pressure fluid in one of the two pressure chambers.

According to the fluid pressure cylinder of the present invention, a high-pressure fluid is sealed in two adjacent pressure chambers among the first to fourth pressure chambers. When the working piston is located closer to the head than the predetermined position, the passage of the high-pressure fluid between two adjacent pressure chambers is allowed. In this case, no pressure difference occurs 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, conduction between the two adjacent pressure chambers is blocked, and the high-pressure fluid in one of the pressure chambers is exhausted. As a result, a thrust corresponding to the pressure difference between two adjacent pressure chambers is generated, and the thrust of the piston rod can be increased near the stroke end. Since the exhaust of the high-pressure fluid is performed at the end of the stroke, the amount of fluid used for increasing the thrust can be suppressed.

It is a sectional view of a fluid pressure cylinder concerning a 1st embodiment. The partial enlarged view in the figure is a cross-sectional view in which the third check valve 56 is enlarged. FIG. 2 is a side view of an end side of the fluid pressure cylinder in FIG. 1. 3A is an enlarged cross-sectional view of the vicinity of the partition wall of the fluid pressure cylinder of FIG. 1, and FIG. 3B is an enlarged cross-sectional view of a state where the working piston approaches the vicinity of the partition wall of FIG. 3A. FIG. 4A is a fluid circuit diagram showing a connection state in an operation process of the hydraulic cylinder according to the embodiment, and FIG. 4B is a fluid circuit diagram showing a connection state in a return process of the hydraulic cylinder in FIG. 4A. FIG. 2 is a cross-sectional view of an operation process of the hydraulic cylinder of FIG. FIG. 2 is a cross-sectional view of the fluid pressure cylinder in FIG. FIG. 2 is a cross-sectional view (part 1) of the fluid pressure cylinder in FIG. 1 in a return step. FIG. 4 is a cross-sectional view (part 2) of the fluid pressure cylinder in FIG. 1 in a return step. FIG. 9A is a plan view of the hydraulic cylinder according to the second embodiment, and FIG. 9B is a side view of the hydraulic cylinder of FIG. 9A. FIG. 10 is a cross-sectional view of the fluid pressure cylinder of FIG. 9A at a stroke start end position. FIG. 11A is a fluid circuit diagram of the drive device of the fluid pressure cylinder of FIG. 9A, showing a connection state of the switching valve in a first position, and FIG. 11B is a view of the switching device in a second position of the drive device of FIG. 11A. FIG. 4 is a fluid circuit diagram showing a connection state of FIG. FIG. 12 is a cross-sectional view of the fluid pressure cylinder in FIG. 9A in a boosting step.

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

(1st Embodiment)
The fluid pressure cylinder 10 according to the present embodiment includes a cylinder body 12 and a driving device 120 as shown in FIGS. 4A and 4B.

(1) The fluid pressure cylinder 10 includes a cylinder body 12 that extends in the axial direction as shown in FIG. As shown in FIG. 2, the cylinder body 12 can be formed in a rectangular shape, and is formed of, for example, a metal material such as an aluminum alloy.

円形 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 includes a head-side main body portion 14 provided on the head side, an end-side main body portion 16 provided on the end side, and a partition wall provided between the head-side main body portion 14 and the end-side main body portion 16. 26. As shown in FIG. 2, the head-side main body 14, the partition 26, and the end-side main body 16 are fastened in the axial direction by connecting rods or bolts 16b.

As shown in FIG. 1, a circular working cylinder chamber 14 a is formed inside the head-side main body 14, and a circular booster cylinder chamber 16 a is formed inside the end-side main body 16. The working cylinder chamber 14a and the booster cylinder chamber 16a are formed with the same inner diameter, and constitute a sliding hole 12a of the cylinder body 12. The working cylinder chamber 14a and the booster cylinder chamber 16a are separated by a partition wall 26.

作動 A working piston 20 is provided in the working cylinder chamber 14a, and a booster piston 22 is provided in the booster cylinder chamber 16a. The working piston 20 and the booster piston 22 are connected to the piston rod 18 that extends through the partition wall 26 and the cylinder body 12 to the end side.

The head-side main body 14 is provided with a head-side port 28, a head cover 46, and a working piston 20. The head cover 46 is attached to the end of the working cylinder chamber 14a on the head side, and the head cover 46 seals the head side of the working cylinder chamber 14a.

ヘッド A head-side port 28 is formed near the head cover 46. The head-side port 28 is formed through the head-side main body 14. The head-side port 28 is provided near the head-side end of the working cylinder chamber 14a and communicates with the working cylinder chamber 14a (first pressure chamber 38) through an opening 28a.

The working piston 20 is accommodated in the working cylinder chamber 14a so as to be slidable in the axial direction. An annular packing mounting groove 21a is formed on the outer peripheral surface of the working piston 20, and the packing 21 is mounted in the packing mounting groove 21a. The packing 21 tightly contacts the inner peripheral surface of the working cylinder chamber 14a while being elastically deformed, thereby airtightly dividing the working 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 working piston 20 and the head cover 46 and is formed closer to the head than the working piston 20. The second pressure chamber 40 is an empty chamber formed between the working piston 20 and the partition 26, and is formed on the end side of the working piston 20. The first pressure chamber 38 communicates with the head-side port 28 via the opening 28a.

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

On the other hand, the end-side main body 16 is provided with the booster piston 22, the rod cover 48, the end-side port 30, and the auxiliary flow path 76.

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

The booster piston 22 airtightly partitions the booster cylinder chamber 16a into a third pressure chamber 42 and a fourth pressure chamber 44 via the packing 23. The third pressure chamber 42 is an empty chamber on the head side of the booster piston 22 and is formed between the booster piston 22 and the partition 26. The fourth pressure chamber 44 is an empty chamber on the end side of the booster piston 22 and is formed between the booster piston 22 and the rod cover 48. The fourth pressure chamber 44 communicates with the end-side port 30.

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

The rod cover 48 is mounted on the end side of the booster cylinder chamber 16a. The rod cover 48 is formed in a disk shape, and an annular packing mounting groove 48d is formed in an outer peripheral portion thereof. A circular ring-shaped packing 48c is mounted in the packing mounting groove 48d. The packing 48c hermetically seals the packing mounting groove 48d.

Around the radial center of the rod cover 48, an insertion hole 48a for inserting the piston rod 18 is formed extending in the axial direction. A rod packing 48b for preventing air from leaking along the piston rod 18 is provided in the insertion hole 48a. An annular damper mounting groove 47a is formed in the end surface of the rod cover 48 on the head side, and the damper 47 is mounted in the damper mounting groove 47a. The damper 47 is made of an elastic member formed in a circular ring shape, and protrudes toward the booster cylinder chamber 16a to prevent collision between the booster piston 22 and the rod cover 48.

抜け Further, a retaining clip 49 for fixing the rod cover 48 is attached to the end side of the rod cover 48. The retaining clip 49 is a plate member engaged with an engaging groove 49 a formed along the inner peripheral surface of the end-side main body 16. The retaining clip 49 is an annular plate member with a part cut out in the circumferential direction, is engaged with the engaging groove 49 a by elastic restoring force, and comes into contact with the end face on the end side of the rod cover 48 so that the rod 49 The cover 48 is prevented from falling off.

The end-side port 30 is formed near the end of the end-side main body 16 on the end side. The end-side port 30 is formed to penetrate from the outer periphery of the end-side main body 16 toward the booster cylinder chamber 16a, and communicates with the fourth pressure chamber 44 at the end-side end of the booster cylinder chamber 16a. I have.

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

The third check valve 56 is provided in the middle of the auxiliary flow path 76. The third check valve 56 has a hollow portion 56a having a diameter larger than that of the auxiliary flow passage 76, and a valve body 56b inserted into the hollow portion 56a. It is a member formed in a bottomed cylindrical cup shape, and the bottom 56c is arranged on the downstream side in the direction in which the flow of air is blocked. An annular projection 56d is formed on the bottom 56c of the valve body 56b to abut the end face of the cavity 56a to close the auxiliary flow path 76 communicating with the cavity 56a.

切 Further, a cutout portion 56e for passing air is formed on a side portion of the valve body 56b. With respect to the air flowing from the bottom 56c side, the annular projection 56d of the valve body 56b is separated from the end face of the cavity 56a, and the air is passed through the cutout 56e. Also, for the air in the opposite direction, the bottom 56c of the valve body 56b receives the pressure of the air, and the annular projection 56d abuts against the end face of the cavity 56a to close the auxiliary flow path 76. And is configured to block the flow of air.

In order to make the operation of the third check valve 56 smooth, an urging member 56f such as a spring for urging the annular projection 56d of the valve body 56b in a direction of contacting the end face of the cavity 56a is inserted into the cavity 56a. It may be provided. Further, a first check valve 52 and a second check valve 54, which will be described later, have the same structure as the third check valve 56.

The partition 26 includes a plate-shaped main body 60 as shown in FIG. 3A. The main body 60 is formed with a first connection portion 63 protruding toward the head and inserted into the working cylinder chamber 14a, and a second connection portion 64 protruding toward the end side and inserted into the booster cylinder chamber 16a. The first connection portion 63 is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the working cylinder chamber 14a, and a packing 63a is mounted on an outer peripheral portion thereof. The second connection portion 64 is formed in a cylindrical shape having an outer diameter substantially equal to the inner diameter of the booster cylinder chamber 16a, and a packing 64a is mounted on an outer peripheral portion thereof. The packing 63a seals the gap between the working cylinder chamber 14a and the first connection portion 63, and the packing 64a seals the gap between the boost cylinder chamber 16a and the second connection portion 64.

貫通 Around the radial center of the partition wall 26, a through portion 61 for inserting the piston rod 18 is formed extending in the axial direction. The through portion 61 is provided with a packing 62 for preventing air from leaking along the piston rod 18.

The partition wall 26 includes a communication path 34, a conduction switching valve 35 provided in the communication path 34, an exhaust path 36, an exhaust path 36, and an exhaust switching valve 37 provided in the exhaust path 36. Having.

The communication path 34 is a flow path that allows air to flow between the second pressure chamber 40 and the third pressure chamber 42, and is inserted into the through hole 65 that passes through the partition wall 26 in the axial direction and the through hole 65. It is composed of an internal flow path 35e of the conduction switching pin 35a and a hole 66b of the stopper 66.

The through hole 65 is formed so as to penetrate the partition wall 26 in the axial direction. The through hole 65 is formed in the large diameter portion 65a formed in the head side, the small diameter portion 65b formed in the center in the axial direction, and formed in the end side. And a stopper insertion hole 65c. The large diameter portion 65a and the stopper insertion hole 65c are formed with a larger inside diameter than the small diameter portion 65b. The conduction switching pin 35a is 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 of the conduction switching pin 35a of the conduction switching valve 35, and is displaced integrally with the conduction switching pin 35a. Further, the stopper 66 stops in the stopper insertion hole 65c, so that the movement of the conduction switching pin 35a toward the head is restricted.

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

付 Further, an urging member 35f is mounted on the end side of the closing portion 35c of the conduction switching pin 35a. The biasing member 35f is made of, for example, a spring or the like, and is inserted into a gap between the large-diameter portion 65a and the conduction switching pin 35a. The urging member 35f urges the conduction switching pin 35a toward the head, and separates the closing portion 35c from the through hole 65 so as to project toward the second pressure chamber 40. That is, the conduction switching valve 35 is configured so as not to hinder the conduction of the communication passage 34 in a state where the conduction switching pin 35a is not pressed toward the head by the operating piston 20.

On the other hand, the exhaust passage 36 is opened at the end face of the partition wall 26 on the first connection portion 63 side, and extends in the axial direction. 71. The detection pin housing 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 displaced integrally with the detection pin 37a. The stopper 68 stops 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.

The connection channel 71 communicates with the detection pin housing hole 67 at an opening 71 a formed on the side of the small diameter portion 67 b. The small-diameter portion 67b has a predetermined area around the opening 71a whose diameter is enlarged, and forms a gap between the small-diameter portion 67b and the exhaust switching valve 37.

The connection flow path 71 is provided with a first check valve 52 that allows air to pass only in the direction from the opening 71 a to the adjustment port 32. The first check valve 52 is arranged in a direction that allows exhaustion of air from the second pressure chamber 40.

The exhaust gas switching valve 37 includes a detection pin 37a. The detection pin 37a includes a pin body 37b extending in a columnar shape in the axial direction, and a flange 37c extending radially outward at a head end of the pin body 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 insertable into the large-diameter portion 67a. A biasing member 37f made of a spring or the like is mounted on the large diameter portion 67a. The urging member 37f is configured to contact the flange portion 37c and urge the detection pin 37a toward the head so that the flange portion 37c projects toward the second pressure chamber 40.

The pin body 37b has 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 on the outer peripheral portion of the pin body 37b at an interval in the axial direction. The packing 37d and the packing 37e are disposed at positions where the detection pin 37a is in close contact with the small-diameter portion 67b and prevents communication between the detection pin housing hole 67 and the connection flow path 71 when the detection pin 37a is not pressed by the operating piston 20. I have. That is, the exhaust switching valve 37 prevents communication with the exhaust path 36 when not pressed by the working piston 20.

補充 The head-side main body 14 near the adjustment port 32 is provided with a replenishment flow path 78 and a second check valve 54. The refill channel 78 communicates with the adjustment port 32 and the second pressure chamber 40. The replenishment flow path 78 is provided with a second check valve 54. One end of the second check valve 54 communicates with the adjustment port 32 via the refill channel 78. Further, the other end of the second check valve 54 communicates with the second pressure chamber 40 via the refill channel 78. The second check valve 54 allows the passage of air only in the direction from the adjustment port 32 to the second pressure chamber 40, and blocks the passage of air in the opposite direction. That is, the second check valve 54 is configured to allow the flow of the air supplied to the second pressure chamber 40 and block the air in the opposite direction.

流体 The hydraulic cylinder 10 of the present embodiment is configured as described above, and is driven by the driving device 120 as shown in FIG. 4A.

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

The switching valve 102 is, for example, a five-port two-position valve, has first to fifth ports 102a to 102e, and switches between a first position (see FIG. 4A) and a second position (see FIG. 4B). It is possible. As shown in FIGS. 4A and 4B, the first port 102a is connected to the head-side port 28 by piping. The second port 102b is connected to the adjustment port 32 by a pipe. The third port 102c is connected to the exhaust port 106 by a pipe. The fourth port 102d is connected to a high-pressure air supply source 104 by a pipe. The fifth port 102e is connected to the exhaust port 106 via a throttle valve 88 by a pipe, and is connected to the end port 30 via a fourth check valve 86.

As shown in FIG. 4A, when the switching valve 102 is at the first position, the first port 102a and the fourth port 102d are connected, and the second port 102b and the third port 102c are connected.

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

When the switching valve 102 is at the second position, the fourth check valve 86 allows the air flow from the head-side port 28 to the end-side port 30, and allows the air to flow from the end-side port 30 to the head-side port 28. Block the flow.

The throttle valve 88 is provided to limit the amount of air in the first pressure chamber 38 exhausted from the exhaust port 106, and is a variable throttle valve capable of changing a passage area so that the exhaust flow rate can be adjusted. Is configured as

An air tank is provided in the middle of the pipe connecting the fourth check valve 86 and the fourth pressure chamber 44 so that the air supplied from the head-side port 28 to the end-side port 30 is accumulated in the return step. Is also good. By providing the air tank, a sufficient amount of air can be accumulated to fill the fourth pressure chamber 44 during the return operation, and the return operation can be stabilized. In this case, the capacity of the air tank may be set to, for example, about half of the maximum capacity of the first pressure chamber 38. If the capacity of the pipe can be sufficiently secured, the air tank is not required.

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

(Start-up process)
In the starting step, the second pressure chamber 40 and the third pressure chamber 42 are filled with high-pressure air before the use of the fluid pressure cylinder 10 is started. The high-pressure air is air having a pressure higher than the atmospheric pressure. Here, the hydraulic cylinder 10 is set at the start position of the stroke as shown in FIG. Further, the switching valve 102 of the driving 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, the high-pressure air from the high-pressure air supply source 104 is introduced into the second pressure chamber 40 via the second check valve 54. The high-pressure air introduced into the second pressure chamber 40 is also introduced into the third pressure chamber 42 via the communication passage 34. Thus, the second pressure chamber 40 and the third pressure chamber 42 are filled with the high-pressure air. The activation process need only be performed once before the first stroke of the hydraulic cylinder 10.

(Operation process)
As shown in FIG. 4A, the operation process of the hydraulic cylinder 10 is performed with the switching valve 102 of the driving device 120 as the first position. The high-pressure air from the high-pressure air supply source 104 is supplied to the head-side port 28 via 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 fourth pressure chamber 44 is connected to the exhaust port 106 via the third check valve 56, the adjustment port 32, and the second port 102b.

高圧 As shown in FIG. 5, in the operation step, the high-pressure air from the high-pressure air supply source 104 flows into the first pressure chamber 38 as shown by the 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 booster piston 22 by the high-pressure air filled in the third pressure chamber 42 have the same magnitude and are oppositely balanced. Does not contribute. Accordingly, a thrust corresponding to the pressure difference between the first pressure chamber 38 adjacent to the working piston 20 and the fourth pressure chamber 44 adjacent to the booster piston 22 is generated in the piston rod 18, and the piston rod 18 is moved toward the end. Stroke toward.

With the stroke of the working piston 20, high-pressure air having an amount equal to the volume of the first pressure chamber 38 is supplied to the hydraulic cylinder 10 from the high-pressure air supply source 104 (see FIG. 4A). With the strokes of the working piston 20 and the booster piston 22, the high-pressure air in the second pressure chamber 40 moves to the third pressure chamber 42 through the communication passage 34. During the operation process, the pressure of the high-pressure air stored 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 with the stroke of the booster piston 22. In this case, the air in the fourth pressure chamber 44 passes through the adjustment port 32 via the third check valve 56 and the auxiliary flow path 76, and as shown in FIG. 4A, the exhaust port 106 through the second port 102b of the switching valve 102. It is exhausted from.

(Strengthening process)
As shown in FIG. 6, with the stroke of the working piston 20, the conduction switching pin 35a (see FIG. 3B) of the conduction switching valve 35 is pressed to the end side, and the detection pin 37a of the exhaust switching valve 37 (FIG. 3B). ) Is also pushed to the end side.

(3) As a result, as shown in FIG. 3B, the closing portion 35c of the conduction 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 seals the gap between the large diameter portion 65a and the closing portion 35c, thereby closing the communication path 34. That is, the flow of air between the second pressure chamber 40 and the third pressure chamber 42 through the communication passage 34 is blocked by the conduction switching valve 35.

When the detection pin 37a of the exhaust gas switching valve 37 is displaced toward the end, the packing 37d that has sealed the gap between the detection pin 37a and the detection pin receiving hole 67 moves to the opening 71a that is recessed. I do. Thereby, the exhaust path 36 is opened, and the adjustment port 32 and the second pressure chamber 40 communicate with each other through the exhaust path 36. The high-pressure air stored in the second pressure chamber 40 is exhausted from the exhaust port 106 via 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 corresponding to the difference between the internal pressures of the second pressure chamber 40 and the first pressure chamber 38 is generated in the working piston 20.

{Circle around (4)} In the booster piston 22, a thrust is generated according to the pressure difference between the high pressure air stored in the third pressure chamber 42 and the pressure in the fourth pressure chamber 44. Thereby, the hydraulic cylinder 10 can increase the thrust near the stroke end. The increase in thrust in the hydraulic cylinder 10 is generated by the exhaust of the high-pressure air in the second pressure chamber 40 in a range where the conduction switching valve 35 and the exhaust switching valve 37 operate.

(Return process)
As shown in FIG. 4B, the return process of the hydraulic cylinder 10 is performed with the switching valve 102 of the driving device 120 set to the second position. The high-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32 via 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 port 28 is connected to the end port 30 via the fourth check valve 86. The head-side port 28 is connected to an exhaust port 106 via a throttle valve 88. As a result, part of the air stored in the first pressure chamber 38 is supplied to the fourth pressure chamber 44 via the fourth check valve 86. Further, the remaining part of the air stored in the first pressure chamber 38 is exhausted from the exhaust port 106.

では As shown in FIG. 7, in the return step, high-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32 of the hydraulic cylinder 10 as shown by an arrow B. The high-pressure air supplied to the adjustment port 32 flows into the second pressure chamber 40 via the refill channel 78 and the second check valve 54. The volume of the high-pressure air supplied to the second pressure chamber 40 is equal to the amount of the high-pressure air exhausted from the second pressure chamber 40 in the boosting step. That is, the high-pressure air required for the boosting step is supplemented in the return step. The amount of high-pressure air supplied at that time is small compared to the amount of high-pressure air required for the stroke of the working piston 20, and only a small amount of high-pressure air needs to be added.

In the return step, since the internal pressure of the second pressure chamber 40 is equal to the internal pressure of the third pressure chamber 42, the force exerted on the working piston 20 by the second pressure chamber 40 and the force exerted on the booster piston 22 by the third pressure chamber 42 And balance and cancel each other out.

On the other hand, a part of the high-pressure air exhausted from the first pressure chamber 38 flows into the fourth pressure chamber 44 as shown by an arrow A. As the evacuation of the air in the first pressure chamber 38 proceeds, the pressure difference between the fourth pressure chamber 44 and the first pressure chamber 38 increases, and the working piston 20, the booster piston 22, and the piston rod 18 move toward the head. Start. Accordingly, the conduction switching valve 35 returns to the 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 switching 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, while the air flows into the fourth pressure chamber 44, the exhaust of the first pressure chamber 38 proceeds, and the working piston 20 and the booster piston 22 return to the starting position of the stroke. Is completed.

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

The fluid pressure cylinder 10 includes, in the fluid pressure cylinder 10, a communication path 34 communicating with the second pressure chamber 40 and the third pressure chamber 42, and an exhaust path 36 communicating with the second pressure chamber 40 as a boost switching mechanism 33. A communication switching valve 35 that opens the communication passage 34 while the operating piston 20 is located closer to the head than the predetermined position, and closes the communication passage 34 when the operating piston 20 moves to the end side from the predetermined position; While the working piston 20 is located on the head side of the predetermined position, the exhaust path 36 is closed, and when the working piston 20 moves to the end side of the predetermined position, the exhaust path 36 is opened to open the second pressure chamber 40. An exhaust switching valve 37 for exhausting the high-pressure fluid. Thereby, the second pressure chamber 40 and the third pressure chamber 42 are separated near the stroke end, and the high pressure air in the second pressure chamber 40 can be exhausted while maintaining the high pressure air in the third pressure chamber 42. As a result, the thrust of the booster piston 22 is added to the thrust of the working piston 20, and the thrust can be increased in the latter half of the stroke.

In the fluid pressure cylinder 10, the partition 26 may have the adjustment port 32, and the exhaust path 36 may exhaust the high-pressure fluid in the second pressure chamber 40 via the adjustment port 32.

In the hydraulic pressure cylinder 10, the boost switching mechanism 33 may be configured such that the exhaust switching valve 37 opens the exhaust passage 36 after the conduction switching valve 35 closes the communication passage 34. Thereby, the outflow of the high-pressure air from the third pressure chamber 42 via the second pressure chamber 40 can be prevented, and the usage amount of the high-pressure air can be suppressed.

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

In the fluid pressure cylinder 10, the exhaust switching valve 37 seals the exhaust passage 36, and has a detection pin 37 a having one end protruding into the second pressure chamber 40. The sealing of the exhaust path 36 may be released by being displaced to the side. Thus, the second pressure chamber 40 can be exhausted through the exhaust path 36 by using the stroke operation of the working piston 20, and the configuration of the apparatus is simplified.

In the fluid pressure cylinder 10, even if the exhaust passage 36 is provided with the first check valve 52 that allows air to pass only in the direction from the second pressure chamber 40 toward the adjustment port 32 and blocks air in the opposite direction. Good. Thereby, in the return process, malfunction of the exhaust gas switching valve 37 can be prevented.

The fluid pressure cylinder 10 further has a replenishment flow path 78 communicating with the adjustment port 32 and the second pressure chamber 40, and the replenishment flow path 78 has air only in a direction from the adjustment port 32 to the second pressure chamber 40. May be provided, and a second check valve 54 for blocking air in the opposite direction may be provided. By providing the second check valve 54, it is possible to suppress an excessive flow of high-pressure air into the second pressure chamber 40 in the return process.

The fluid pressure cylinder 10 may further include an auxiliary flow path 76 that communicates with the fourth pressure chamber 44 and the adjustment port 32. Thereby, in the operation step and the boosting step, the air in the fourth pressure chamber 44 can be exhausted through the adjustment port 32.

In the above-described fluid pressure cylinder 10, the auxiliary flow path 76 is provided with the third check valve 56 that allows only air in the direction from the fourth pressure chamber 44 toward the adjustment port 32 and blocks air in the opposite direction. May be. Thus, in the return step, when high-pressure air is supplied to the adjustment port 32, high-pressure air is prevented from flowing into the fourth pressure chamber 44, and the consumption of high-pressure air can be suppressed.

The fluid pressure cylinder 10 further includes 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. The driving device 120 includes a switching valve 102 and a high pressure It has an air supply source 104, an exhaust port 106, and a fourth check valve 86. At a first position of the switching valve 102, the first pressure chamber 38 communicates with the high-pressure air supply source 104 and the fourth pressure chamber The first pressure chamber 38 communicates with the fourth pressure chamber 44 via the fourth check valve 86 at the second position of the switching valve 102. In addition, the first pressure chamber 38 may communicate with the exhaust port 106, and the second pressure chamber 40 may communicate with the high-pressure air supply source 104 via the adjustment port 32. Thus, in the return step, the air accumulated in the first pressure chamber 38 can be supplied to the fourth pressure chamber 44, so that the consumption of high-pressure air can be suppressed.

In the above-described fluid pressure cylinder 10, a throttle valve 88 may be provided between the first pressure chamber 38 and the exhaust port 106. Thereby, the amount of air supplied to the fourth pressure chamber 44 can be appropriately adjusted.

(2nd Embodiment)
As shown in FIG. 9A, the fluid pressure cylinder 10A of this embodiment has a head-side main body 14A and an end-side main body 16A. In the present embodiment, a high-pressure fluid is sealed in the end-side main body 16A. In order to further increase the thrust at the stroke end, the size (width and height) of the end-side main body 16A is made larger than the size of the head-side main body 14A.

よう As shown in FIG. 9B, the head-side main body 14A and the end-side main body 16A have a rectangular cross section. The head-side main body 14A and the end-side main body 16A are connected in the axial direction by connecting rods or bolts.

As shown in FIG. 10, the cylinder body 12A of the fluid pressure cylinder 10A includes a head-side main body 14A and an end-side main body 16A, both of which are connected in the axial direction via a partition wall 126. The head-side main body 14A is provided with a head-side port 28A and an end-side port 30A. An adjustment port 32A is provided near the end on the end side of the end-side main body 16A.

A storage air exhaust port 162 for discharging the high-pressure air sealed in the booster cylinder chamber 116a is formed near the outer periphery of the partition 126. The storage air exhaust port 162 communicates with the third pressure chamber 42 via the adjustment valve 160. The stored air exhaust port 162 discharges high-pressure air stored in the booster cylinder chamber 116a during maintenance of the fluid pressure cylinder 10A or the like, or introduces high-pressure air into the booster cylinder chamber 116a when starting up. Used for

挿 In the center of the partition 126, an insertion hole 126c is formed for slidably inserting the piston rod 18A. The insertion hole 126c is provided with a packing 118 for preventing leakage of fluid in the axial direction. The partition part 126 is provided with a head-side connection part 126a that extends toward the head and is inserted into the working cylinder chamber 14a. On the end side of the partition wall 126, an end-side connection portion 126b inserted into the booster cylinder chamber 116a is provided. An annular buffer member 124 for preventing collision with the booster piston 22A is attached to the end-side connection portion 126b.

The end-side main body 16A has a main body 116. Inside the main body 116, a booster cylinder chamber 116a composed of a circular hollow portion is formed. The boost cylinder chamber 116a extends in the axial direction. Inside the booster cylinder chamber 116a, a booster piston 22A is slidably disposed in the axial direction. The booster piston 22A is connected to the piston rod 18A. A magnet 24 and a packing 23 are mounted on an outer peripheral portion of the booster piston 22A. The booster piston 22A partitions the booster cylinder chamber 116a into a third pressure chamber 42 on the head side and a fourth pressure chamber 44 on the end side.

(4) The booster piston 22A is provided with a conduction switching valve 35A that switches the conduction state of the high-pressure fluid between the third pressure chamber 42 and the fourth pressure chamber 44 that are adjacent in the axial direction. The conduction switching valve 35A includes a through hole 122 that penetrates the booster piston 22A in the axial direction, and a conduction switching pin 35a inserted into the through hole 122.

The through hole 122 has an end-side enlarged diameter portion 122a, a reduced diameter portion 122b, and a head-side enlarged diameter portion 122c. The conduction switching pin 35a of the conduction switching valve 35A is the same as the conduction switching pin 35a described with reference to FIG. 3A. The rod portion 35d of the conduction switching pin 35a is inserted into the reduced diameter portion 122b. Further, a closing portion 35c of the conduction switching pin 35a is disposed on the end-side enlarged-diameter portion 122a side. The conduction switching pin 35a projects to the end side by the urging force of the urging member 35f.

(4) The high-pressure air is configured to be conducted between the third pressure chamber 42 and the fourth pressure chamber 44 via the through hole 122 and the internal flow path 35e of the conduction switching pin 35a. That is, in the present embodiment, a communication path is formed by the through hole 122 and the internal flow path 35e. When the booster piston 22A moves to the end side, the conduction switching pin 35a is pressed by the rod cover 48A, and the closing portion 35c and the packing 35b on the outer periphery thereof are inserted into the through-hole 122 to close the through-hole 122. , The conduction between the third pressure chamber 42 and the fourth pressure chamber 44 is prevented.

The rod cover 48A is provided near the end on the end side of the end-side main body 16A, and seals the end on the end side of the booster cylinder chamber 116a. The rod cover 48A is provided with an exhaust switching valve 37A that switches exhaust of high-pressure air in the fourth pressure chamber 44. The exhaust switching valve 37A includes a through hole 139 that penetrates the rod cover 48A in the axial direction, and a detection pin 137 inserted into the through hole 139.

The end of the through hole 139 on the end side is sealed by a lid member 150, and a detection pin 137 is provided on the head side of the lid member 150. The detection pin 137 is urged toward the head by an urging member 140 such as a spring disposed between the lid member 150 and the detection pin 137. Therefore, the tip of the detection pin 137 on the head side protrudes into the fourth pressure chamber 44.

環状 An annular packing 141 and a packing 142 are mounted on the outer peripheral portion of the base end 138 of the detection pin 137 so as to be spaced apart in the axial direction. The packing 141 and the packing 142 seal a 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 channel 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 area 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. These

packings

146 and 148 keep the ventilation groove 144 airtight. The adjustment port 32A can communicate with the fourth pressure chamber 44 via 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 path.

When the detection pin 137 is moved to the head side, 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 booster piston 22A moves to the end side, the detection pin 137 is pressed to the end side, and the

packings

141 and 142 move to the end side with respect to the flow path 143. When the

packings

141 and 142 move to the end side of the flow path 143, the fourth pressure chamber 44 and the adjustment port 32A communicate.

流体 The hydraulic cylinder 10A of the present embodiment configured as described above is driven by the driving 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 switching valve 102, a high-pressure air supply source 104, an exhaust port 106, and a fifth check valve 108. I have. The driving device 120A is configured to supply high-pressure air to the first pressure chamber 38 of the operation cylinder chamber 14a in an operation process. Further, as shown in FIG. 11B, the driving device 120A supplies a part of the air accumulated in the first pressure chamber 38 to the second pressure chamber 40 and supplies the air to the fourth pressure chamber 44 in the return step. It is configured to supply high-pressure air.

The switching valve 102 is, for example, a 5-port 2-position valve, has first to fifth ports 102a to 102e, and switches between a first position (see FIG. 11A) and a second position (see FIG. 11B). It is possible. As shown in FIGS. 11A and 11B, the first port 102a is connected to the head-side port 28A by piping. The second port 102b is connected to the adjustment port 32A and the downstream side of 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 a high-pressure air supply source 104 by a pipe. The fifth port 102e is connected to the exhaust port 106 via a throttle valve 88 by a pipe, and is connected to the end port 30A and the upstream side of the fifth check valve 108 via a fourth check valve 86. .

As shown in FIG. 11A, when the switching valve 102 is at the first position, the first port 102a and the fourth port 102d are connected, and the second port 102b and the third port 102c are connected.

11B, when the switching valve 102 is at the second position, the first port 102a and the fifth port 102e are connected, and the second port 102b and the fourth port 102d are connected. The switching valve 102 is switched between a first position and a second position by a pilot pressure from a high-pressure air supply source 104 or an electromagnetic valve.

When the switching valve 102 is at 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 allows the air to flow from the end-side port 30A to the head-side port 28A. Block the flow. Further, when the switching valve 102 is at the second position, the fifth check valve 108 blocks the flow of the high-pressure air from the second port 102b toward the end-side port 30A.

流体 The hydraulic cylinder 10A and its driving device 120A according to the present embodiment are configured as described above, and the operation and operation thereof will be described below.

(Operation process)
As shown in FIG. 11A, the operation step of the hydraulic cylinder 10A is performed with the switching valve 102 of the driving device 120A as the first position. The high-pressure air from the high-pressure air supply source 104 is supplied to the head-side port 28 via 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 via the end-side port 30A and the fifth check valve 108. The adjustment port 32A is connected to the exhaust port 106.

高圧 As shown in FIG. 10, in the operation step, 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, a thrust toward the end side is generated in the working piston 20. As a result, the piston rod 18A strokes toward the end side. Since the high-pressure air sealed in the third pressure chamber 42 and the fourth pressure chamber 44 is conducted through the conduction switching valve 35A, no thrust is generated in the booster piston 22A.

With the stroke of the working piston 20, high-pressure air corresponding to the volume of the first pressure chamber 38 is supplied to the hydraulic cylinder 10A from the high-pressure air supply source 104 (see FIG. 11A). During the operation process, the pressure of the high-pressure air stored in the second pressure chamber 40 and the third pressure chamber 42 is kept constant. Further, the air in the second pressure chamber 40 is exhausted from the second pressure chamber 40 with the stroke of the working 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.

(Strengthening process)
As shown in FIG. 12, with the stroke of the boost piston 22A, the conduction switching pin 35a of the conduction switching valve 35A is pressed toward the head, and the detection pin 37a of the exhaust switching valve 37A is pressed toward the end.

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

When the detection pin 37a of the exhaust switching valve 37A is displaced to the end side, the

packings

141 and 142 that have sealed the gap between the detection pin 37a and the through hole 139 come off 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 stored in the fourth pressure chamber 44 is exhausted from the exhaust port 106. That is, while the state where the high-pressure air is stored in the third pressure chamber 42 is maintained, the internal pressure of the fourth pressure chamber 44 decreases. Thus, a thrust corresponding to the difference between the internal pressures of the fourth pressure chamber 44 and the third pressure chamber 42 is generated in the booster piston 22A. Since this thrust is added to the thrust of the working piston 20, the thrust of the fluid pressure cylinder 10A increases near the stroke end. As described above, the increase in the thrust of the fluid pressure cylinder 10A is generated by exhausting the high-pressure air in the fourth pressure chamber 44 in a range where the conduction switching valve 35A and the exhaust switching valve 37A operate.

(Return process)
As shown in FIG. 11B, the return process of the hydraulic cylinder 10A is performed by setting the switching valve 102 of the driving device 120A to the second position. The high-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32A via 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 28A is connected to the end-side port 30A via the fourth check valve 86. The head-side port 28A is connected to the exhaust port 106 via the throttle valve 88. As a result, part of the air stored in the first pressure chamber 38 is supplied to the fourth pressure chamber 44 via the fourth check valve 86. Further, the remaining part of the air stored in the first pressure chamber 38 is exhausted from the exhaust port 106.

In the return step, high-pressure air from the high-pressure air supply source 104 is supplied to the adjustment port 32A of the hydraulic 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 boosting step is replenished. The amount of high-pressure air to be replenished at this time is small compared to the amount of high-pressure air required for the stroke of the working piston, and only a small amount of high-pressure air needs to be added.

On the other hand, a part of the high-pressure air exhausted from the first pressure chamber 38 flows into the second pressure chamber 40. As the exhaust of the air in the first pressure chamber 38 progresses, the pressure difference between the fourth pressure chamber 44 and the first pressure chamber 38 increases, and the working piston 20 moves to the head side. Then, the working piston 20 and the booster piston 22A return to the starting position of the stroke, and the return process is completed. Thus, since the air required for returning the working piston 20 is supplied from the first pressure chamber 38, it is not necessary to supply high-pressure air to the second pressure chamber 40.

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

In the fluid pressure cylinder 10A of this embodiment, a high-pressure fluid is sealed in the third pressure chamber 42 and the fourth pressure chamber 44, and the boost switching mechanism 33A includes a conduction switching valve 35A provided on the boost piston 22A and a rod cover. An exhaust switching valve 37A provided at 48A is provided. According to the fluid pressure cylinder 10A, the thrust can be increased at the stroke end without providing a complicated lock mechanism. Further, since a mechanical lock mechanism for connecting the piston and the piston rod is not required, incompatibility with respect to an axial impact is less likely to occur, and the reliability is excellent.

In addition, in the fluid pressure cylinder 10A of the present embodiment, the diameter of the booster piston 22A can be larger than the diameter of the working piston 20. Therefore, by increasing the diameter of the booster piston 22A, the diameter of the working piston 20 can be reduced while maintaining the thrust at the stroke end, and the consumption of high-pressure air can be further reduced.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. No.

That is, in the above-described embodiment, the example in which the

driving devices

120 and 120A of the

hydraulic cylinders

10 and 10A are arranged outside the

hydraulic cylinders

10 and 10A has been described, but the present invention is not limited to this. . Some or all of the members constituting the driving

devices

120 and 120A may be built in the cylinder body 12.

Also, a configuration is adopted in which high-pressure fluid is sealed in the first pressure chamber 38 and the second pressure chamber 40 of the fluid pressure cylinder 10, an operating stroke is performed by the booster piston 22, and an additional thrust is generated from the working piston 20 in the boosting process. May be.

Claims

A cylinder body (12) having a sliding hole (12a) extending in the axial direction;
A partition (26) separating the sliding hole into a working cylinder chamber (14a) on the head side and a booster cylinder chamber (16a) on the end side;
An operation piston (20) disposed in the operation cylinder chamber, and dividing the operation cylinder chamber into a first pressure chamber (38) on the head side and a second pressure chamber (40) on the end side;
An intensifying piston (22) arranged in the intensifying cylinder chamber, and dividing the intensifying cylinder chamber into a third pressure chamber (42) on the head side and a fourth pressure chamber (44) on the end side;
A piston rod (18) connected to the working piston and the booster piston and extending to the end side through the partition wall;
Among the first pressure chamber, the second pressure chamber, the third pressure chamber, and the fourth pressure chamber, a high-pressure fluid is sealed in two adjacent pressure chambers,
While the working piston is located closer to the head than the predetermined position, while permitting the passage of the high-pressure fluid between the two pressure chambers, when the working piston moves to the end side from the predetermined position, A booster switching mechanism (33) for preventing conduction of the high-pressure fluid between the two pressure chambers and exhausting the high-pressure fluid in one of the two pressure chambers;
Fluid pressure cylinder.
The fluid pressure cylinder according to claim 1, wherein a high-pressure fluid is sealed in the second pressure chamber and the third pressure chamber.
The boost switching mechanism,
A communication path (34) communicating with the second pressure chamber and the third pressure chamber;
An exhaust passage (36) communicating with the second pressure chamber;
A conduction switching valve (35) for opening the communication passage while the operation piston is located on the head side of the predetermined position, and closing the communication passage when the operation piston moves to the end side of the predetermined position; ,
While the operating piston is located closer to the head than the predetermined position, the exhaust path is closed, and when the operating piston moves to the end side than the predetermined position, the exhaust path is opened to open the second pressure chamber. An exhaust switching valve (37) for exhausting the high-pressure fluid;
A hydraulic cylinder having:
The hydraulic cylinder according to claim 2, wherein the communication path, the exhaust path, the conduction switching valve, and the exhaust switching valve are provided in the partition.
The hydraulic cylinder according to claim 1, wherein a high-pressure fluid is sealed in the third pressure chamber and the fourth pressure chamber,
The boost switching mechanism,
A communication path (35e) communicating with the third pressure chamber and the fourth pressure chamber;
An exhaust passage communicating with the fourth pressure chamber;
While the operating piston is located closer to the head than the predetermined position, while opening the communication path, when the operating piston moves to the end side than the predetermined position, a conduction switching valve that closes the communication path,
While the operating piston is located closer to the head than the predetermined position, the exhaust path is closed, and when the operating piston moves to the end side from the predetermined position, the exhaust path is opened to open the fourth pressure chamber. An exhaust switching valve that exhausts high-pressure fluid;
A hydraulic cylinder having:
The hydraulic cylinder according to claim 4, wherein the communication passage and the conduction switching valve are provided in the booster piston.
The fluid pressure cylinder according to claim 5, further comprising: a rod cover (48) for sealing an end of the fourth pressure chamber on an end side, wherein the rod cover connects the exhaust passage and the exhaust switching valve. Equipped with a hydraulic cylinder.
5. The fluid pressure cylinder according to claim 2, wherein the cylinder body has an adjustment port (32) communicating with the exhaust path, and the exhaust path exhausts high-pressure fluid through the adjustment port. Pressure cylinder.
5. The fluid pressure cylinder according to claim 2, wherein the exhaust switching valve opens the exhaust passage after the conduction switching valve closes the communication passage.
9. The fluid pressure cylinder according to claim 2, wherein one end of the conduction switching valve protrudes toward one of the two pressure chambers and the other end is inserted into the communication passage. A fluid pressure cylinder having a conduction switching pin (35a), wherein the conduction switching pin is axially pressed with the displacement of the working piston, thereby closing the communication passage.
9. The fluid pressure cylinder according to claim 2, wherein a base end of the exhaust switching valve is inserted into the exhaust passage to seal the exhaust passage, and a tip end of the exhaust switching valve is a head. A fluid pressure cylinder having a detection pin (37a) projecting to the side, wherein the detection pin is pressed by the operating piston or the booster piston and displaced to the end side, whereby the sealing of the exhaust passage is released.
4. The fluid pressure cylinder according to claim 2, wherein the exhaust passage is provided with a first check valve (52) that allows fluid to pass only in a direction in which the fluid is discharged and prevents fluid in the opposite direction. Fluid pressure cylinder.
4. The fluid pressure cylinder according to claim 2, further comprising a refill channel (78) communicating with the second pressure chamber, wherein the refill channel passes a fluid flowing toward the second pressure chamber. 7. A fluid pressure cylinder provided with a second check valve (54) to be operated.
The fluid pressure cylinder according to claim 7, further comprising an auxiliary flow path (76) communicating with the fourth pressure chamber and the adjustment port, wherein the auxiliary flow path is provided from the fourth pressure chamber to the adjustment port. A fluid pressure cylinder provided with a third check valve (56) for passing only fluid in the direction toward the adjustment port and blocking fluid in the opposite direction.
The fluid pressure cylinder 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 driving device has a switching valve (102), a high-pressure fluid supply source (104), an exhaust port (106), and a fourth check valve (86),
In a first position of the switching valve, the first pressure chamber communicates with the high-pressure fluid supply source, and the fourth pressure chamber and the boost 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 via the fourth check valve, the first pressure chamber communicates with the exhaust port, and the second pressure chamber communicates with the exhaust port. A pressure chamber in communication with the high pressure fluid supply;
Fluid pressure cylinder.
The fluid pressure cylinder according to claim 4, further comprising a driving device (120A) connected to the first pressure chamber, the second pressure chamber, and the fourth pressure chamber,
The driving device has a switching valve, a high-pressure fluid supply source, an exhaust port, and a fourth check valve,
In a first position of the switching valve, the first pressure chamber communicates with the high-pressure fluid supply source, and the fourth pressure chamber and the second pressure chamber communicate with the exhaust port.
In a second position of the switching valve, the first pressure chamber communicates with the second pressure chamber via the fourth check valve, the first pressure chamber communicates with the exhaust port, and the fourth pressure chamber communicates with the exhaust port. A pressure chamber in communication with the high pressure fluid supply;
Fluid pressure cylinder.
The hydraulic cylinder according to claim 14 or 15, wherein a throttle valve (88) is provided between the first pressure chamber and the exhaust port.