JP2676110B2 - Fluid pressure continuously operated reciprocating actuator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure driven continuously operating reciprocating actuator, and more particularly to an actuator for continuously reciprocating an output rod by receiving supply of pressurized air or hydraulic pressure. Regarding

(Prior art)

Conventionally, as a fluid pressure driven continuous operation type reciprocating actuator of this type, a spring return type single acting fluid pressure cylinder is incorporated in a housing, and a fluid pressure supply port and a discharge port are connected to a direction switching valve with respect to the working chamber of the cylinder. When the working chamber and the supply port are communicated with each other, the piston and the output rod are driven to advance against the return spring by the fluid pressure (usually compressed air) when the mechanism is switched. When the working chamber communicates with the discharge port, the piston and the output rod are driven backward by the return spring, and the control fluid pressure flow passage is switched by the control valve mechanism linked to the piston to switch the directional switching valve mechanism. It is known to be configured so as to cause it.

The applicant of the present application, as disclosed in Japanese Patent Publication No. 55-40761, puts into practical use a device that can be manufactured at a relatively low cost by eliminating various drawbacks of the conventional device, making it compact and weighing, and being relatively reliable. Turned into

[Problems to be solved by the invention]

The reciprocating actuator has a structure in which the piston and the output rod are driven to advance by the fluid pressure supplied to the working chamber, and the piston and the output rod are reset by the return spring. Remaining.

The case where the above reciprocating actuator is applied to an actuator for driving a plunger type hydraulic pump will be described as an example. The total length of the reciprocating stroke of the piston for accommodating the return spring and the length of the return spring in the maximum compression state will be described. Since the above spring accommodating chamber must be provided, the actuator becomes larger, and if the reciprocating cycle of the piston is accelerated to increase the output, that is, the discharge amount of the hydraulic pump, the return spring becomes unable to follow and the return spring is damaged. Since there is a limit to speeding up, and if the stroke of the piston and output rod is increased to increase the discharge rate of the hydraulic pump, the spring length of the return spring increases, so a large return spring is required and the overall size increases. If the spring force of the return spring is increased in order to improve the followability of the return spring, The versatility of the hydraulic pump force can not be driven by and low pressure of the fluid pressure decreases the discharge pressure of the hydraulic pump lowers decreases, there are various problems such as.

An object of the present invention is to provide a fluid pressure driven continuous operation type reciprocating actuator capable of returning and driving a piston by fluid pressure instead of a return spring.

[Means for solving the problem]

A fluid pressure driven continuous operation type reciprocating actuator according to the present invention is provided with a double acting fluid pressure cylinder having a piston and an output rod fixed to the piston in a housing, and the piston is fluidly advanced to the fluid pressure cylinder. A forward motion moving chamber to be driven and a backward motion moving chamber to drive the piston backward by fluid pressure are provided, and the forward motion moving chamber is selectively provided as a supply position connecting to the fluid pressure supply port and a discharge position connecting to the discharge port. A switching valve body that can be switched to a switch position, a biasing means that biases the switching valve body to the supply position, and a valve working chamber that switches the switching valve body to the discharge position by fluid pressure against the biasing force. A valve mechanism is provided, and the valve working chamber is connected to the discharge port when the piston is at the backward limit position and the piston is at the backward limit position and the forward limit position through the valve member that extends from the piston and is inserted into the switching valve body. When it is between A control valve mechanism is provided which seals the working chamber and connects the valve working chamber to the fluid pressure supply port when the piston is at the advance limit position. A relief valve mechanism is provided that opens when the pressure is higher than the set pressure and connects the return motion chamber to the discharge port. When the piston moves backward, the fluid pressure in the return motion chamber is set to the second set pressure which is equal to or lower than the first set pressure. A supply valve mechanism that opens the valve when the pressure is less than the pressure and connects the return motion chamber to the fluid pressure supply port is provided.

[Action]

In the fluid pressure driven continuous operation type reciprocating actuator according to the present invention, when the piston is in the retracted limit position while the pressure fluid is being supplied to the fluid pressure supply port, the valve working chamber is set to the discharge port by the control valve mechanism. Since it is connected, the switching valve body is held at the supply position by the biasing means, the pressure fluid is supplied from the fluid pressure supply port to the forward movement moving chamber, and the piston is returned to the backward movement moving chamber by the fluid pressure in the forward movement moving chamber. Driven forward against the fluid pressure of. The control valve mechanism seals the valve working chamber in the fluid pressure discharge state until the piston reaches the retreat limit position and the advance limit position, so that the switching valve body is held at the supply position. Therefore, as described above, the pressure fluid is supplied to the forward motion chamber, and the piston is driven to advance. During this time, the fluid in the return motion chamber is pressurized, and when it becomes higher than the first set pressure, the fluid is relieved by the relief valve mechanism, so that the fluid is held at the first set pressure.

After that, when the piston reaches the advance limit position, the valve working chamber is connected to the fluid pressure supply port by the control valve mechanism, and the switching valve body is displaced by the fluid pressure in the valve working chamber against the biasing force of the biasing means. The forward movement moving chamber is connected to the discharge port, and the piston starts the backward drive by the pressure fluid having the first set pressure in the backward movement moving chamber. Since the valve working chamber is sealed in the fluid pressure filled state until the piston reaches the retracted limit position from the advanced limit position, the switching valve body is held at the discharge position. As the piston moves backward, the fluid pressure in the homeward moving chamber becomes the first
When the pressure drops below the second set pressure below the set pressure, the supply valve mechanism opens and the pressure fluid is supplied to the return operation chamber.
The set pressure is maintained and the piston moves backward. Thus, when the piston reaches the backward limit position, the valve operating chamber is connected to the discharge port by the control valve mechanism, the switching valve body is switched to the supply position, and the piston is reciprocally driven in the same manner as above. .

In the reciprocating actuator of the present invention, since the fluid pressure equal to or lower than the first set pressure and equal to or higher than the second set pressure is held in the backward movement chamber and the piston is driven backward by the fluid pressure, the return spring is provided. It can be omitted, the output of the reciprocating actuator can be increased by speeding up the reciprocating cycle, and the reciprocating stroke of the piston can be freely designed to be large or small as required. Can be formed in a working chamber as small as required for the reciprocating stroke of the piston, so that the reciprocating actuator can be downsized. Moreover, since the first set pressure and the second set pressure can be configured to be adjustable as needed, the versatility of the reciprocating actuator can be improved.

〔The invention's effect〕

According to the fluid pressure driven continuous operation type reciprocating actuator according to the present invention, as described in the above [Operation], the pressure in the reciprocating motion chamber can be adjusted by the relief valve mechanism and the supply valve mechanism regardless of the position of the piston. By holding the fluid in a predetermined range of pressure and driving the piston backward by the pressure fluid, the return spring can be omitted, the reciprocating cycle can be speeded up, that is, the output can be increased. The reciprocating stroke can be freely designed to be large or small as required, the reciprocating chamber can be downsized to reduce the reciprocating actuator, and the versatility of the reciprocating actuator can be improved. The effect of is obtained.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The present embodiment is an example in which the present invention is applied to an air-driven hydraulic pump in which a plunger is driven by a compressed air (hereinafter, referred to as pressurized air) driven continuous operation type reciprocating actuator.

As shown in FIG. 1, the hydraulic pump HP includes a reciprocating actuator AC and a pump main body PC, and a housing 10 of the reciprocating actuator AC includes an upper housing 11, an intermediate housing 12, and a lower housing 13. It is configured by integrally connecting with a common bolt 14.

A double-acting air cylinder 20 is provided in the lower half of the housing 10, a piston 22 is mounted in a cylinder hole 21 of the air cylinder 20, and a plunger 24 is provided below the output rod 23 extending from the lower end of the piston 22. Formed and cylinder hole
A forward motion chamber 25 is formed on the upper side of the piston 22 of the 21, and a backward motion chamber 26 is formed on the lower side of the piston 22.

A plunger hole 15 is provided in the lower housing 13,
The plunger 24 is driven into and out of the plunger hole 15, and the oil sucked into the plunger hole 15 from the suction port 16 via the suction check valve 17 is compressed by the plunger 24 and discharged to the discharge port 19 via the discharge check valve 18. To be done.

A pressurizing air supply port 3 to which pressurizing air (for example, 5.0 kg / cm ² G) is supplied from an external pressurizing air supply source is provided on an upper side portion of the housing 10, and inside the upper end portion of the housing 10. An exhaust chamber 5 communicating with the atmosphere via a muffler 4 serving as an exhaust port is formed therein.

 Next, the switching valve mechanism 30 will be described.

An annular member 32 housed in the intermediate housing 12 is fixed to the upper surface of the partition wall 31 of the intermediate housing 12, and the annular member 32
On the outer peripheral side of the pressurizing air supply path connected to the pressurizing air supply port 3
33 is formed, a switching valve body 35 is mounted inside the recess 34 of the partition wall 31 and the annular member 32, and a lower piston portion 36 at the lower end of the switching valve body 35 is mounted in the recess 34 in a hermetically slidable manner. In addition, in the middle part of the switching valve body 35, an annular and flanged switching valve portion 37
Is formed, the upper piston portion 38 of the upper end portion of the switching valve body 35 is fitted in the cylinder hole 39 of the annular member 32 in a hermetically slidable manner,
An annular exhaust passage 41 is formed between the switching valve portion 37 and the lower piston 36 on the outer peripheral portion of the switching valve body 35 by the exhaust passage 40 and is connected to the exhaust chamber 5. An annular exhaust passage 41 is formed on the outer peripheral side of the switching valve portion 37 by the passage 42a. An annular passage 42 that communicates with the forward movement moving chamber 25 is formed. The annular member 32 is formed with a first valve seat 44 on which the annular first valve surface 43 of the upper surface of the switching valve portion 37 abuts, and the partition wall 31 is the annular second valve surface 45 of the lower surface of the switching valve portion 37. A second valve seat 46 against which the switching valve element 35 is formed between the first valve surface 43 and the upper piston portion 38.
An annular pressure-receiving chamber 48 connected to the pressurized air supply passage 33 is formed on the outer peripheral side by the passage 47, and the switching valve body 35 is elastically biased downward by a spring 49.

When the second valve surface 45 of the switching valve element 35 comes into contact with the second valve seat 46, the space between the first valve surface 43 and the first valve seat 44 is opened, and the forward movement moving chamber 25
Is communicated with the pressurized air supply port 3 through the passage 42a, the annular passage 42, the pressure receiving chamber 48, the passage 47 and the pressurized air supply passage 33. Therefore, the position of the switching valve element 35 at this time is referred to as a supply position.

When the first valve surface 43 of the switching valve element 35 abuts on the first valve seat 44, the second valve seat 45 and the second valve seat 46 are opened, and the forward movement moving chamber
25 is a passage 42a, an annular passage 42, an annular exhaust passage 41 and an exhaust passage 40.
To communicate with the exhaust chamber 5. Therefore, the position of the switching valve 35 at this time is called a discharge position.

When the valve operating chamber 50 is formed by the lower piston 36 and the recess 34 of the switching valve body 35, and the pressurized air is not supplied to the valve operating chamber 50, the switching valve body 35 presses the pressurized air in the pressure receiving chamber 48 and the spring 49. When the valve working chamber 50 is urged to the supply position by and the pressurized air is supplied to the valve operating chamber 50 as described later, the switching valve body 35 is switched to the discharging position.

 Next, the control valve mechanism 60 will be described.

The valve member 61 on the rod fixed to the central portion of the piston 22 extends upward by inserting through the sliding hole 62 of the partition wall 31 and the insertion hole 63 of the switching valve body 35, and the middle portion of the valve member 61. Has a small diameter part 64
A pair of upper and lower O-rings 65 and 66, which are airtightly pressed against the outer peripheral surface of the valve member 61, are attached to the inner peripheral portion of the sliding hole 62, and the inner peripheral portion of the upper end of the insertion hole 63 is formed. An O-ring 67, which is pressed against the outer peripheral surface of the valve member 61 in an airtight manner, is attached to the partition wall 31, and a pressurized air passage 68 communicating with the pressurized air supply port 3 is attached to the partition wall 31.
It is formed up to the outside of 65 and 66.

When the piston 22 is in the retracted limit position shown in FIG. 1, the small-diameter portion 64 releases the O-ring 67,
The valve working chamber 50 is communicated with the exhaust chamber 5 through an annular gap 69 outside the valve member 61 of the insertion hole 63, and when the piston 22 is at the advance limit position shown in FIG. When the O-ring 65 is sealed and the O-ring 65 is unsealed by the small-diameter portion 64, the pressurized air passage 68 communicates with the valve working chamber 50, and when the piston 22 is between the retreat limit position and the advance limit position, both The valve working chamber 50 is sealed by the O-rings 65 and 67.

Next, the relief valve mechanism 80 and the supply valve mechanism 81 will be described.

This reciprocating actuator AC drives the piston 22 and the output rod 23 to advance by the pressurized air supplied to the forward movement moving chamber 25, and the first set pressure (for example, the first set pressure always stored in the backward movement moving chamber 26). , 0.5 kg / cm ² G) or less and a second set pressure (eg 0.4 kg / cm ² G) or more pressurized piston
22 and the output rod 23 are configured to drive backward. Therefore, the relief valve mechanism 80 that performs a relief operation when the pressure of the pressurized air in the backward movement moving chamber 26 of the piston 22 is higher than the first set pressure, and the backward movement moving chamber 26 of the backward movement of the piston 22 A supply valve mechanism 81 for supplying pressurized air when the pressure of the pressurized air therein is less than the second set pressure is provided as follows.

An annular supply valve element 83 is fitted on the annular member 32 in the intermediate housing 12 so as to be slidable in an airtight manner, and an annular relief valve element is provided on the upper housing 11 above the supply valve element 83.
84 is fitted in a hermetically slidable manner, an annular third valve surface 85 is formed on the lower surface of the relief valve body 84, and the third valve surface 85 is in contact with the upper end portion of the supply valve body 83. A seat 86 is formed, an annular fourth valve surface 87 is formed on the upper surface of the interrupted outer peripheral step portion of the supply valve body 83, and a fourth valve surface 87 is formed on the lower surface of the collar portion 89 of the upper housing 11.
Is formed on the upper surface of the flange portion 89, and a first restricting portion 90 for restricting the lower limit position of the relief valve element 84 is formed on the upper surface of the collar portion 89. The supply valve element 83 is provided on the outer peripheral portion of the annular member 32. A second restricting portion 91 that restricts the lower limit position of is formed.

The upper housing 11, the relief valve body 84, and the supply valve body 83
An annular pressure receiving chamber 92 is formed between the supply valve body 83 and the annular member.
An annular back pressure chamber 93 communicated with the annular pressure receiving chamber 92 by a communication hole 93a is formed between the 32, and the annular pressure receiving chamber 92 includes a passage 94, an annular passage 95 common to the bolt holes, and a hole at the lower end of the intermediate housing 12. It is communicated with the return motion chamber 26 by 96.

Further, the relief valve body 84 is elastically biased downward by the first spring 97 which is a compression coil spring for setting the first set pressure, and the supply valve body 83 cooperates with the first spring 97 to set the second set pressure. A second spring 98, which is a compression coil spring for setting pressure, is elastically biased upward.

The relief valve element 84 and the supply valve element 83 are provided when the pressure of the pressurized air in the reciprocating motion chamber 26 is less than or equal to the first set pressure and greater than or equal to the second set pressure.
Holds the state shown in FIG. 1, and the third valve face 85 and the third valve seat
86 and the fourth valve face 87 and the fourth valve seat 88 are closed.

When the pressure of the pressurized air in the return motion chamber 26 becomes higher than the first set pressure during the advancing operation of the piston 22, the relief valve body 84 moves upward due to the pressurized air in the annular pressure receiving chamber 92, and the third valve surface
Since the pressurized air is relieved by moving 85 away from the third valve seat 86, the pressure in the return motion chamber 26 is maintained at the first set pressure. When the pressure of the pressurized air in the reciprocating motion chamber 26 becomes lower than the second set pressure during the backward movement of the piston 22, the relief valve body 84 supplies the second spring 98 against the second spring 98 by the spring force of the first spring 97. Since the valve body 83 is pushed downward, the fourth valve face 87 separates from the fourth valve seat 88, and pressurized air is supplied from the pressurized air supply passage 33 to the annular pressure receiving chamber 92, so that the return motion chamber 26 Is maintained at the second set pressure.

A synthetic resin member having excellent wear resistance is embedded in the first to fourth valve faces 43, 45, 85, 87.

Next, the operation of the reciprocating actuator AC will be described.

When the piston 22 is at the backward limit position while the pressurized air is being supplied to the pressurized air supply port 3, the control valve mechanism
Since the valve operating chamber 50 is connected to the exhaust chamber 5 by 60, the switching valve body 35 is held at the supply position by the pressurized air in the pressure receiving chamber 48 and the urging force of the spring 49, and the pressurized air is supplied by the pressurized air. The piston 22 is supplied from the port 3 to the forward movement moving chamber 25, and the piston 22 is driven forward by the pressurized air in the forward movement moving chamber 25 against the pressurized air in the backward movement moving chamber 26. The control valve mechanism 60 seals the valve working chamber 50 in the air pressure exhausted state until the piston 22 reaches the retreat limit position and the advance limit position.
Are held in the feed position. Therefore, as described above, the supply of the pressurized air to the outward motion chamber 25 is continued, and the piston 22 is driven to advance. During this time, the air in the return motion chamber 26 is pressurized,
When the pressure becomes higher than the first set pressure, the relief valve mechanism 80 relieves the pressure so that the first set pressure is maintained.

After that, when the piston 22 reaches the advance limit position, the valve working chamber 50 is connected to the pressurized air supply port 3 by the control valve mechanism 60, and the switching valve body 35 is pressurized by the pressurized air in the valve working chamber 50.
Since the pressurizing air of 48 and the urging force of the spring 49 can be switched to the discharge position, the forward moving chamber 25 is connected to the exhaust chamber 5, and the compressed air of the first set pressure in the backward moving chamber 26 is pressed. This causes the piston 22 to start backward drive. Since the valve working chamber 50 is sealed in the pressurized air filled state until the piston 22 reaches the retracted limit position from the advanced limit position, the switching valve body 35 is held at the discharge position. When the air pressure in the reciprocating motion chamber 26 drops below the second set pressure that is less than or equal to the first set pressure in response to the retreat of the piston 22, the supply valve mechanism 81 opens to supply pressurized air to the reciprocating motion chamber 26. Therefore, the second set pressure is maintained, and the retreat of the piston 22 is continued. Thus, when the piston 22 reaches the retreat limit position, the valve operating chamber 50 is connected to the exhaust chamber 5 by the control valve mechanism 60, the switching valve body 35 is switched to the supply position, and the same operation is repeated thereafter, and the piston 22 reciprocates. Will be driven.

As is clear from the above description, in the reciprocating actuator AC, the switching valve mechanism 30 and the control valve mechanism 60 supply / exhaust the pressurized air to / from the forward moving chamber 25 in synchronization with the reciprocating operation of the piston 22. Further, the relief valve mechanism 80 and the supply valve mechanism 81 constantly hold the pressurized air below the first set pressure and above the second set pressure in the backward motion chamber 26, so that the piston 22 continuously reciprocates. Repeatedly, the plunger 24 at the tip of the output rod 23 continuously repeats the reciprocating motion within the plunger hole 15. Therefore, in the hydraulic pump main body PC, oil suction and compression / discharge are continuously repeated.

As described above, in the hydraulic pump HP of the present embodiment, since the piston 22 is configured to be driven backward by the pressurized air, it is possible to omit the return spring for driving the piston 22 backward. The reciprocating cycle can be speeded up to increase the output of the reciprocating actuator AC, and the reciprocating stroke of the piston 22 can be freely designed to be large or small as necessary. Since the size can be made as small as necessary for the reciprocating stroke of 22, the hydraulic pump HP itself can be downsized.

Next, a modified example of the above embodiment will be described with reference to FIGS. The same mechanisms as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

<Modification 1> Instead of the O-ring 67 of the control valve mechanism 60 of the above embodiment, a control valve mechanism 60A as shown in FIG. 3 is used.

The switching valve body 35A is provided with a tubular portion 100, the tubular portion 100 is provided with a second valve member 102 for opening and closing the valve hole 101, and the muffler 4 is provided with a valve closing spring 103 composed of a compression coil spring.
The second valve member 102 is elastically biased downward by the valve closing spring 103, and the rod-shaped valve member 61A, which is below the second valve member 102 and fixed to the center of the piston 22, is the same as that of the above-described embodiment. The portion above the lower end of the small diameter portion 64 of the valve member 61 is removed.

The other parts of the control valve mechanism 60A are the same as those in the above-mentioned embodiment, and the description thereof will be omitted.

In the control valve mechanism 60A, when the piston 22 is at the retracted limit position as shown, the valve member 61A causes the valve closing spring 103
Since the second valve member 102 is pushed up against the spring force to open the valve hole 101, the valve working chamber 50 has the annular gap 69, the valve hole 101, and the tubular portion 100.
Since it is connected to the exhaust chamber 5 via the passage of
When A is held at the supply position and the piston 22 is at the advance limit position, the second valve member 102 is lowered by the valve closing spring 103 to close the valve hole 101 and the upper end portion of the valve member 61A becomes O.
As it descends below the ring 66, the pressurized air passage 68 communicates with the valve working chamber 50, the valve working chamber 50 is filled with pressurized air, and the switching valve body 35A is switched to the discharge position. The other operations are the same as those in the above-mentioned embodiment, so that the description thereof will be omitted.

<Modification 2> Instead of the switching valve portion 37 of the switching valve body 35 of the above embodiment, a fourth
As shown in the figure, in the switching valve mechanism 30A, a switching valve portion 37B having an annular seal member 110 is provided in the switching valve body 35B.
As shown in FIG. 4, when the switching valve body 35B is at the supply position, the seal member 110 contacts the inner peripheral surface of the second valve seat 46B,
The forward motion chamber 25 communicates with the pressurized air supply port 3 through the passage 42a, the annular passage 42, the annular gap 111, the pressure receiving chamber 48, the passage 47, and the pressurized air supply passage 33.

On the other hand, when the switching valve body 35B is switched to the discharge position, the seal member 110 abuts on the inner peripheral surface of the first valve seat 44B, and the annular gap 111 is in communication with the annular exhaust passage 41, and the forward movement is performed. The chamber 25 includes the passage 42a, the annular passage 42, and the annular gap 11
1. The exhaust chamber 5 is communicated with the annular exhaust passage 41 and the exhaust passage 40. The other operations are the same as those in the above-mentioned embodiment, and the description thereof will be omitted.

<Modification 3> The relief valve mechanism 80 and the supply valve mechanism 81 of the above embodiment are omitted, and instead of them, the relief valve mechanism 80C and the supply valve mechanism 81C.
Are provided at corners 13a and 13b of the lower housing 13.

Explaining the relief valve mechanism 80C, as shown in FIG. 5, the relief valve chamber 121 is recessed from the lower end surface of the corner portion 13a, and the relief valve chamber 121 is provided from the bottom of the return motion chamber 26.
An exhaust hole 122 communicating with the relief valve chamber 121 is formed in the upper portion of the corner portion 13a, and an annular passage 95 common to the bolt hole is formed in the upper portion of the corner portion 13a. An exhaust passage 124 communicating with the chamber 5 is formed.

A screw member 125 is provided in the lower portion of the relief valve chamber 121 by being screwed to the lower housing 13, and an adjust screw 126 is screwed into the screw member 125 to adjust the screw 126.
A recess 127 is formed in the upper part of the relief valve chamber 121, and a groove 128 is formed in the lower end of the adjusting screw 16. A first spring 129, which is a compression coil spring for setting a first set pressure, is provided in the recess 127, and a valve 130 for opening and closing the exhaust hole 122 from the inside is provided above the first spring 129. The valve element 130 is elastically biased upward by the first spring 129.

Next, the supply valve mechanism 81C will be described. As shown in FIG. 6, a supply valve chamber 141 is recessed from the lower end surface of another corner portion 13b separated from the corner portion 13a of the lower housing 13. A supply hole 142 that communicates with the supply valve chamber 141 is formed from the bottom of the return motion chamber 26, and a supply passage 143 that communicates the annular passage 95 with the supply valve chamber 141 is formed at the top of the corner 13b. A supply passage 144 that connects the annular passage 95 to the pressurized air supply 33 is formed in the upper portion of the housing 12.

A screw member 145 is provided in the lower housing at the lower part of the supply valve chamber 141.
It is provided by screwing on 13 and the screw member 145
The screw 146 is screwed, and a recess 147 is formed in the upper portion of the adjusting screw 146 located inside the supply valve chamber 141, and a groove 148 is formed in the lower end portion of the adjusting screw 146. The recess 147 is provided with a second spring 149 composed of a pressure seed coil spring for setting a second set pressure.
A valve 15 for opening and closing the supply passage 143 is provided above the spring 149.
0 is provided, and the valve element 150 is elastically biased upward by the second spring 149.

In the relief valve mechanism 80C and the supply valve mechanism 81C configured as described above, when the pressure of the pressurized air in the return motion chamber 26 is equal to or lower than the first setting and equal to or higher than the second setting pressure, the valve element 130.
The valve 50 holds the state shown in FIGS. 5 and 6, the valve element 130 seals the exhaust hole 122, and the valve element 150 seals the supply passage 143.

When the pressure of the pressurized air in the reciprocating motion chamber 26 becomes higher than the first set pressure during the advancing operation of the piston 22, the valve 130 moves downward due to the air pressure, and the valve 130 seals the exhaust hole 122. Since the stop is released and the pressurized air is relieved to the exhaust chamber 5 through the exhaust hole 122, the exhaust passage 123, the annular passage 95 and the exhaust passage 124, the return motion chamber 26 is maintained at the first set pressure. When the pressure of the pressurized air in the backward movement chamber 26 becomes lower than the second set pressure during the backward movement of the piston 22, the valve element 150 moves downward due to the air pressure from the pressurized air supply passage 33, and the valve element 150 moves downward. Since the supply passage 143 is unsealed by the 150 and pressurized air is supplied to the return movement chamber 26, the pressure in the return movement chamber 26 is maintained at the second set pressure.

Also, the grooves 128 of the adjust screws 126 and 146, respectively.
By operating 148 with a tool such as a screw driver, the spring force of the first spring 129 and the second spring 149 can be adjusted, and the setting of the first set pressure and the second set pressure can be changed. Further, in place of the supply valve body 83, the relief valve body 84, the first spring 97, and the second spring 98, which are relatively large members configuring the relief valve mechanism 80 and the supply valve mechanism 81 of the above-described embodiment, the lower housing is replaced. Since the relief valve mechanism 80C and supply valve mechanism 81C can be made compact by effectively using 13, the reciprocating actuator AC itself can be made compact.
It can be lightweight.

In the present embodiment, hydraulic pressure may be used instead of the pressurized air, and the present invention is applicable to various devices using reciprocating drive such as a hydraulic pressure boosting pump and a gas pressure boosting pump, in addition to the hydraulic pump. Can be done.

[Brief description of the drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of the hydraulic pump when the piston is at the backward limit position, and FIG. 2 is when the piston is at the forward limit position. 3 to 6 show a modified example of the present embodiment, and FIG. 3 is a partial vertical sectional view of a hydraulic pump showing a modified example of the control valve mechanism, FIG. Is a partial vertical sectional view of a hydraulic pump showing a modified example of a switching valve portion, FIG. 5 is a vertical sectional view of a hydraulic pump showing a modified example of a relief valve mechanism, and FIG. 6 is a hydraulic pump showing a modified example of a supply valve mechanism. FIG. AC ... Reciprocating actuator, 3 ... Pressurized air supply port,
5 ... Exhaust chamber, 10 ... Housing, 20 ... Double acting air cylinder, 22 ... Piston, 23 ... Output rod, 25 ... Forward working chamber, 26 ... Return working chamber, 30 ... Switching Valve mechanism, 35 / 35B …… Switching valve element, 49 …… Spring, 50 …… Valve working chamber, 60 ・ 60A …… Control valve mechanism, 61
…… Valve member, 80 ・ 80C …… Relief valve mechanism, 81 ・ 81C …… Supply valve mechanism.

Claims (1)

(57) [Claims] 1. A double-acting fluid pressure cylinder having a piston and an output rod fixed to the piston is provided in a housing, and a forward-moving moving chamber for advancing and driving the piston by fluid pressure is provided in the fluid pressure cylinder. A return motion chamber that is driven backward by pressure is provided, and a switching valve body that can be selectively switched between a supply position that connects the forward motion chamber to the fluid pressure supply port and a discharge position that connects to the discharge port, and this switching valve body. A switching valve mechanism including a biasing means for biasing the valve body to the supply position and a valve working chamber for switching the switching valve body to the discharge position by fluid pressure against the biasing force is provided, and the switching valve mechanism extends from the piston and switches. The valve working chamber is connected to the discharge port when the piston is at the backward limit position through the valve member inserted through the valve body, and the valve working chamber is opened when the piston is between the backward limit position and the forward limit position. Sealed and piston is in the advanced position Control valve mechanism that connects the valve working chamber to the fluid pressure supply port, and when the piston moves forward, the valve opens when the fluid pressure in the return movement chamber is higher than the first set pressure. A relief valve mechanism for connecting the chamber to the discharge port is provided, and the valve is opened to return when the fluid pressure in the return operation chamber is less than the second set pressure below the first set pressure during the backward movement of the piston. A fluid pressure driven continuous operation type reciprocating actuator, characterized in that a supply valve mechanism for connecting the fluid pressure supply port to the fluid pressure supply port is provided.