JPH09100809A - Pressure circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bound phenomenon in a piston in the vicinity of a cylinder lowering end in a pressure circuit in which a piston is set in a balance condition in compliance with a load of a workpiece. SOLUTION: When a piston P is brought close to the lowering end 71 in a cylinder C, loads of a pressure sensitive cylinder 9 and a workpiece W are supported by means of a sliding rod 63 and a lowering stopper 62. These loads do not work on the oil in a pressure sensitive oil chamber 19, so that no oil pressure is generated in the pressure sensitive oil chamber 19. A pressure sensitive valve 103 is closed, while a pressure reducing valve 105 and a regulating valve 109 are also closed, so that a pressure regulating piston 20 in a main valve 6 is not driven downward, and as a result, no pressurizing air is newly supplied to an action chamber 4. Therefore, the piston P is not driven upward, and no bound phenomenon is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder device having a piston for receiving a load of a work and a cylinder for slidably accommodating the piston, a load detecting means for detecting the load of the work, and a gas for driving the piston. Adjusting means for adjusting the pressure according to the detected load.

[0002]

2. Description of the Related Art Conventionally, a cylinder device having a piston for receiving a load of a work and a cylinder for slidably accommodating the piston, and a supply / discharge means for supplying / discharging pressurized gas for driving the piston to the cylinder device. It has been known that a pressure circuit that includes a cylinder and that generates a pressure that counteracts the load of the work in the cylinder device and that can raise and lower the work by merely applying a small external force.

However, in the conventional configuration, the pressure setting of the supply / discharge means must be adjusted every time the work is changed.
It was troublesome. As a solution to such a problem, the applicant has proposed a pressure circuit capable of keeping the piston of the cylinder device in a balanced state without performing a special adjusting operation according to the work (special feature). Wishhei 7-169737
issue).

An example of this pressure circuit will be described with reference to FIG. As shown in FIG. 2, in the conventional pressure circuit 1,
A piston P is slidably accommodated in the cylinder device 2, and one end of a rod 3 is fixed to the piston P.
A handle 5 is attached to the rod 3 so that the rod 3
A work holder 7 is connected to the tip of the. The work holder 7 includes a pressure-sensitive cylinder 9 and a hook 11, and a pressure-sensitive piston 13 connected to the rod 3 is slidably accommodated in the pressure-sensitive cylinder 9. The pressure sensitive cylinder 9 is closed except for the oil passage 15 provided at the upper end and the vent 17 provided at the lower end.
A pressure-sensitive oil chamber 19 is formed on the rod 3 side of No. 3. The work W is attached to the hook 11.

An oil passage 21 is connected to the oil passage 15 of the pressure sensitive cylinder 9. The other end of the oil path 21 is connected to a hydraulic chamber 33 of the pressure reducing valve 31. The hydraulic chamber 33 of the pressure reducing valve 31 is provided with a diaphragm 37 having a receiving plate 35 at the center.
, And a pressure-sensitive chamber 39 is formed on the opposite side of the diaphragm 37.

The receiving plate 35 of the diaphragm 37 is a pressure reducing valve 3.
The correction spring 4 between the adjusting stem 41 screwed to the head 1
5 and the correction spring 45 controls the pressure-sensitive chamber 39.
Is biased to the side. However, the biasing force of the correction spring 45 is adjusted by rotating the adjustment stem 41 and moving it up and down.

The hydraulic chamber 33 of the pressure reducing valve 31, the oil passage 21 and the pressure sensitive oil chamber 19 of the pressure sensitive cylinder 9 are filled with hydraulic oil, and the hydraulic pressure of the pressure sensitive oil chamber 19 is transmitted to the hydraulic chamber 33. Is. The area of the pressure-sensitive piston 13 on the rod 3 side (pressure-sensitive area X) is substantially equal to the area of the piston P on the rod side (pressure-receiving area Y). In this state, the pressure in the pressure-sensitive oil chamber 19 is set to be substantially equal to the pressure in the working chamber 4.

In addition to the hydraulic chamber 33 and the pressure sensitive chamber 39, the pressure reducing valve 31 is connected to a ventilation chamber 49 and an air supply source R which communicate with the pressure sensitive chamber 39 by a bypass 47. 51 is provided. In addition, in the pressure reducing valve 31,
A valve body 53 having a shaft penetrating from the air guide chamber 51 to the pressure sensing chamber 39 is housed.

An urging spring 55 for urging the valve body 53 toward the closed position is attached to the lower side of the valve body 53, and the upper end of the valve body 53 projects into the pressure sensing chamber 39 to receive the diaphragm 37. 35
Is in contact with As the force acting on the valve element 53, the weight of the valve element 53, the downward force of the correction spring 45, and the upward force of the urging spring 55 are substantially balanced, and the valve element 53
Will be released if the pressure in the hydraulic chamber 33 acting in the opening direction via the receiving plate 35 of the diaphragm 37 is superior to the pressure in the pressure sensitive chamber 39, and the air guide chamber 51 and the ventilation chamber 49 will be communicated. . However, since the biasing force of the correction spring 45 is adjusted by the adjusting stem 41, the valve body 53 should be in the open position even if the pressure in the hydraulic chamber 33 does not exceed the pressure in the pressure sensing chamber. You can

Further, the vent chamber 49 is connected to the supply / discharge port 30 of the main valve 6 via the orifice 57, thereby communicating with the pressure adjusting piston chamber 24 and communicating with the atmosphere via the needle valve 59. . The pressure adjusting chamber 8 of the main valve 6 is connected to the working chamber 4 of the cylinder device 2. This pressure regulation chamber 8
Is connected to the air supply chamber 10 connected to the air supply source R, and is disconnected from the air supply chamber 10 by the air supply valve body 12.
An exhaust chamber 14 that is open to the atmosphere is connected to the pressure adjustment chamber 8, and communication between the pressure adjustment chamber 8 and the exhaust chamber 14 is cut off by an exhaust valve 16.

A piston chamber 18 is provided above the exhaust chamber 14 independently of the exhaust chamber 14, and the piston chamber 18 is divided into a control chamber 22 and a pressure regulating piston chamber 24 by a pressure regulating piston 20. To be done. A stem 26 penetrating the pressure adjustment chamber 8 is connected to the pressure adjustment piston 20, and the lowering of the stem 26 pushes down the air supply valve body 12, thereby communicating the pressure adjustment chamber 8 with the air supply chamber 10. As the stem 26 rises, the exhaust valve body 16 is raised, and the pressure regulating chamber 8 and the exhaust chamber 14 are communicated. Further, the control chamber 22 is connected to the pressure regulation chamber 8 via a bypass 28.

In this pressure circuit 1, when the work W is attached to the hook 11 of the work holder 7, the load of the work W acts as a force to pull down the pressure sensitive cylinder 9 and reduce the volume of the pressure sensitive oil chamber 19. Therefore, hydraulic pressure is generated in the pressure-sensitive oil chamber 19 according to the load of the work. This oil pressure is guided to the oil pressure chamber 33 of the pressure reducing valve 31 by the oil path 21.

In the pressure reducing valve 31, the pressure in the hydraulic chamber 33 rises due to the hydraulic pressure introduced from the pressure sensitive oil chamber 19 by the oil passage 21. As a result, the diaphragm 37 is displaced toward the pressure sensing chamber 39, the valve body 53 is set to the open position, and the pressure sensing chamber 39 and the air supply source R are communicated. The pressurized air that has flowed into the pressure sensing chamber 39 is guided to the pressure adjustment piston chamber 24 of the main valve 6, and increases the pressure of the pressure adjustment piston chamber 24. At the same time, the pressure in the pressure-sensitive chamber 39 also increases.

In the main valve 6, since the pressure adjusting piston 20 descends due to the pressure increase in the pressure adjusting piston chamber 24, the stem 26
Also descends. Thereby, the air supply valve body 12 is lowered, and the air supply chamber 10 and the pressure regulation chamber 8 are communicated. Then, pressurized air from the air supply source R flows from the air supply chamber 10 to the working chamber 4 of the cylinder device 2 via the pressure regulating chamber 8. The pressure in the working chamber 4 is
Acts as a force to raise the piston P. This power is
It acts on the pressure-sensitive piston 13 via the rod 3. The force for displacing the pressure-sensitive piston 13 acts on the pressure-sensitive cylinder 9 via the oil pressure in the pressure-sensitive oil chamber 19. After all, the force for raising the piston P works as the force for raising the work W.

When the pressure in the working chamber 4 rises, the pressure in the control chamber 22 communicating therewith also rises. This control room 22
Pressure acts as a force to push up the pressure adjustment piston 20. If the pressure in the control chamber 22 is superior to the pressure in the pressure adjustment piston chamber 24, the pressure adjustment piston 20 is raised and the air supply valve 1
Reference numeral 2 denotes a closed position, and supply of pressurized air to the pressure regulating chamber 8 and the working chamber 4 is stopped. If the pressure in the control chamber 22 is higher, the pressure adjustment piston 20 is raised beyond the neutral position, the exhaust valve body 16 is set to the open position, and the compressed air in the pressure adjustment chamber 8 and the working chamber 4 is discharged. Therefore, the pressure in the control chamber 22 decreases. When the pressure in the control chamber 22 and the pressure in the pressure adjustment piston chamber 24 are balanced, the pressure adjustment piston 2
0 is a neutral position, and no air is supplied to the pressure regulating chamber 8 and the working chamber 4, and no exhaust is performed from the pressure regulating chamber 8 and the working chamber 4.

On the other hand, if the pressure in the pressure sensing chamber 39 of the pressure reducing valve 31 communicating with the pressure regulating piston chamber 24 of the main valve 6 rises,
The diaphragm 37 is displaced toward the hydraulic chamber 33, and the valve body 53 cuts off the communication between the pressure-sensitive chamber 39 and the air supply source R. As a result, the pressure increase in the pressure regulating piston chamber 24 is stopped. However,
Since the gas in the pressure adjustment piston chamber 24 is gradually released by the needle valve 59, the pressure in the pressure adjustment piston chamber 24 gradually decreases. Then, the valve body 53 communicates the pressure sensing chamber 39 and the air supply source R again, so that the pressure regulating piston chamber 24
Pressure recovers.

As described above, the pressure in the pressure regulating piston chamber 24 is made substantially constant by opening and closing the valve body 53. As described above, since the pressure in the control chamber 22 and the pressure in the pressure adjustment piston chamber 24 are balanced, if the pressure receiving areas on the pressure adjustment piston chamber 24 side and the control chamber 22 side of the pressure adjustment piston 20 are equal, the operation is The pressure of the chamber 4 = the pressure of the pressure regulating chamber 8 = the pressure of the control chamber 22 = the pressure of the pressure regulating piston chamber 24 = the pressure of the pressure sensitive chamber 39.

Considering the force acting on the valve body 53 at this time, (force due to the pressure in the pressure sensing chamber 39 + biasing force due to the biasing spring 55) = (force due to the pressure in the hydraulic chamber 33 + correction spring 45)
+ The weight of the valve body 53). As previously mentioned,
(The biasing force of the correction spring 45 + the weight of the valve body 53) = the biasing force of the biasing spring 55, the pressure of the pressure sensing chamber 39 = the hydraulic chamber 3
3 pressure.

Since the pressure in the hydraulic chamber 33 is equal to the pressure in the pressure sensitive oil chamber 19, the pressure in the pressure regulating piston chamber 24 = the pressure in the pressure sensitive chamber 39 = the pressure in the pressure sensitive oil chamber 19. As a result, the pressure in the pressure adjusting piston chamber 24 depends on the pressure in the pressure-sensitive oil chamber 19, that is, the load on the work W.

By the way, as described above, the pressure in the control chamber 22 and the pressure adjusting piston chamber 2 are controlled by supplying and discharging the pressurized air in the pressure adjusting chamber 8.
When the pressure at 4 is balanced, the supply and discharge of pressurized air to and from the pressure regulating chamber 8 and the working chamber 4 are not performed. As a result, the piston P and the work W are brought into a balanced state in which the piston P and the work W are not displaced vertically.

Therefore, the piston P of the cylinder device 2 can be brought into a balanced state without any special adjustment operation according to the work W. When an upward external force is applied to the handle 5 from this balanced state, this force acts as a force for raising the piston P. As a result, even if the pressure in the working chamber 4 decreases even slightly, the pressure in the control chamber 22 decreases, and the pressure adjusting piston 20 lowers. Therefore, the air supply valve body 12 is set to the open position, and pressurized air is supplied to the working chamber 4. Therefore, the workpiece W can be easily lifted together with the piston P by applying a slight external force to the handle 5.

As described above, according to the pressure circuit illustrated in FIG. 2, it is possible to perform a special adjusting operation according to the workpiece.
It is possible to bring the pistons of the cylinder device into a balanced state.

[0023]

However, when the piston P hits the descending end of the cylinder device 2 when the work W is lowered in the pressure circuit shown in FIG. 2, the inertia of the work W causes the pressure-sensitive oil chamber 19 to move. Pressure rises sharply. When the pressure in the pressure-sensitive oil chamber 19 rises, the pressurized air is supplied to the working chamber 4 accordingly, and the pressure in the working chamber 4 rises, so that the piston P is raised, and a bounce phenomenon occurs.

This bouncing phenomenon is not limited to the use of hydraulic pressure as a means for detecting the load of the work as in the pressure circuit of FIG. 2, but the load of the work is detected by other means, and the detected load is determined according to the detected load. Similarly, in a pressure circuit provided with a means for supplying and discharging pressurized gas for driving the piston to and from the cylinder device.

According to the present invention, there is provided a cylinder device having a piston for receiving a load of a work and a cylinder for slidably accommodating the piston, a load detecting means for detecting the load of the work, and a load detecting means for detecting the load. It is an object of the present invention to prevent such a bouncing phenomenon in a pressure circuit provided with a supply / discharge means for supplying / discharging the pressure gas for driving the piston to / from the cylinder device.

[0026]

As a means for solving the above-mentioned problems, a pressure circuit according to claim 1 is provided with a cylinder device having a piston for receiving a load of a work and a cylinder for slidably accommodating the piston. A load circuit for detecting the load of the work, and an adjusting means for adjusting the gas pressure for driving the piston according to the detected load, in the direction of lowering the work. When the piston is displaced, a support means is provided for supporting the load of the work when the distance between the piston and the descending end of the cylinder becomes a predetermined distance or less.

The pressure circuit according to a second aspect is the pressure circuit according to the first aspect, further comprising a descent regulating means for regulating the descent of the work when the distance between the piston and the descending end of the cylinder reaches a predetermined distance. It is characterized by that. A pressure circuit according to a third aspect is the pressure circuit according to the first or second aspect, further comprising an ascending regulation means that regulates an ascent of the work when a distance between the piston and an ascending end of the cylinder reaches a predetermined distance. It is characterized by

[0028]

In the pressure circuit according to claim 1, which has the above-mentioned structure, the support means has a predetermined distance between the piston and the descending end of the cylinder when the piston is displaced in the direction in which the work is lowered. The load of the work is supported when the following occurs. Then, the load of the work exerted on the load detection means is reduced. Therefore, the value detected by the load detecting means is smaller than the actual load of the work.
Then, the adjusting means sets the gas pressure for driving the piston to a pressure corresponding to a load smaller than the actual load of the work, so that the piston is not driven. Therefore, the bound phenomenon does not occur.

The supporting means preferably supports the total load of the work, but since the load detected by the load detecting means is sufficiently smaller than the actual load of the work, the total load of the work is Bearing is not mandatory. Further, the descending end of the cylinder means the end to which the piston moves when lowering and displacing the work, and is not necessarily located below, such as when the cylinder is installed horizontally. Absent. In addition, the rising end means the end facing the falling end,
It is not always located above.

In the pressure circuit according to the second aspect of the invention, the lowering restricting means restricts the lowering of the work when the distance between the piston and the lower end of the cylinder reaches a predetermined distance. By restricting the lowering of the work, the effect of the configuration according to claim 1 can be further ensured. Note that the support means can also serve as the descent control means.

In the pressure circuit according to the third aspect of the present invention, the lifting control means restricts the lifting of the work when the distance between the piston and the lifting end of the cylinder reaches a predetermined distance. Without this lifting restriction means, when the piston hits the rising end of the cylinder when the work is lifted, the value detected by the load detection means decreases due to the inertia of the work. Then, the adjusting means accordingly lowers the gas pressure for driving the piston, so that the piston momentarily descends.

However, since the lifting control means controls the lifting of the work, the load detection means is not affected by the inertia of the work. Therefore, the above-described piston lowering does not occur.

[0033]

Next, one embodiment of the present invention will be described with reference to the drawings. The pressure circuit 102 of this specific example includes a pressure sensitive valve 103 and a pressure reducing valve 1 having the same structure as the pressure reducing valve 31 shown in FIG.
I am using 05. Therefore, regarding each part of the pressure sensitive valve 103 and the pressure reducing valve 105, the pressure reducing valve 31 of FIG.
The same part number as the above (however, suffixes a and b are added for distinction) is used, and the description of the structure is omitted. Similarly, the relief valve 107 only lacks a configuration in which the pressure sensing chambers 39a and 39b and the ventilation chambers 49a and 49b are communicated with each other by the bypasses 47a and 47b, and the other structures are the pressure reducing valve 31 and the pressure sensing valve 1.
03 and the pressure reducing valve 105, the same part number as the pressure reducing valve 31 in FIG. 2 (however, a suffix c is added for distinction) is used for each part of the relief valve 107, and the structure will not be described. Omit it.

The hydraulic pressure is introduced when the pressure sensitive valve 10 is used.
Since there are only three hydraulic chambers 33a, only this hydraulic chamber 33a
In the pressure reducing valve 105 and the relief valve 107, the same portions are referred to as diaphragm chambers 33b and 33c. Further, since the main valve 6 is also similar to the main valve 6 in FIG. 2, the same part number as in FIG. 2 is used and the description of the structure is omitted.

As shown in FIG. 1, the pressure circuit 1 of this example.
The cylinder device 60 of No. 02 is equipped with a cylinder C in which the piston P and the rod 3 are housed, which is similar to the cylinder device 2 of the conventional example shown in FIG. 2, and between the piston P and the descending end 71 of the cylinder C. The working chamber 4 is formed, and the handle 5 is fixed to the rod 3. As in the conventional example of FIG. 2, the pressure-sensitive cylinder 9 and the hook 11 are closed except for the oil passage 15 and the vent 17, and a pressure-sensitive oil chamber 19 is formed on the rod 3 side of the pressure-sensitive piston 13. The work holding body 7 including is connected to the cylinder device 60 via the rod 3. In addition, the work W is attached to the hook 11,
It can be removed.

On the other hand, the cylinder device 60 includes a cylinder C.
Is provided at a position corresponding to the rising end 72 of the cylinder C along the radial direction of the cylinder C, and at a position corresponding to the falling end 71 of the cylinder C at the position corresponding to the falling end 71 of the cylinder C. A stopper 62 is provided.

A sliding rod 63, the lower end of which is fixed to the pressure sensitive cylinder 9, slidably penetrates the lowering stopper 62. At the upper end of the sliding rod 63, a disk-shaped head 6
A guide shaft 69 having 8 is fixed. Guide shaft 6
9 includes a ring-shaped sliding ring 64 having a concave center side,
65 are loosely fitted to each other in a back-to-back state, and the sliding rings 64 and 65 are slidable along the axial direction of the guide shaft 69. A compression coil spring 66 is interposed between the sliding rings 64 and 65, and the sliding rings 64 and 65 are urged by the compression coil spring 66 in directions away from each other.

Further, the pressure circuit 102 is composed of the pressure sensitive valve 1
03, the pressure reducing valve 105, and the relief valve 107, the adjustment valve 109 is provided. The adjusting valve 109 closes the diaphragm chamber 113 partitioned by the diaphragm 111, the sub control chamber 115, the sub pressure regulating chamber 119, which is cut off by the valve body 117, the sub air supply chamber 121, and the valve body 117 ( An urging spring 123 that urges upward) is provided. The urging force of the urging spring 123 is adjusted to slightly exceed the load of the valve element 117, and the diaphragm chamber 113
When the pressure of exceeds the pressure of the sub control chamber 115, the valve body 117 is displaced to the open position side (downward), and the sub pressure regulating chamber 119 and the sub air supply chamber 121 communicate with each other.

Next, the cylinder device 60, the main valve 6,
The pipelines connected to the pressure sensitive valve 103, the pressure reducing valve 105, the relief valve 107, and the adjusting valve 109 will be described.
First, the working chamber 4 of the cylinder device 60 is the pressure regulating chamber 8 of the main valve 6.
And the rising end 72 side of the cylinder C is open to the atmosphere.

The air supply chamber 10 of the main valve 6 is connected to the air supply source R, the pressure adjusting chamber 8 and the control chamber 22 are in communication with each other, and further connected to the sub control chamber 115 of the adjusting valve 109. Further, the pressure regulating piston chamber 24 of the main valve 6 is connected to the auxiliary pressure regulating chamber 119 of the regulating valve 109, and is also connected to the diaphragm chamber 33c and the air introducing chamber 51c of the relief valve 107 via the needle valve 129. .

The diaphragm chamber 113 of the adjusting valve 109 is
It is connected to the diaphragm chamber 33b of the pressure reducing valve 105 and the pressure sensing chamber 39c of the relief valve 107, is connected to the ventilation chamber 49a of the pressure sensing valve 103 via the orifice 125, and is open to the atmosphere via the needle valve 127. .
In addition, the sub air supply chamber 121 is a ventilation chamber 49b of the pressure reducing valve 105.
It is connected to the.

The hydraulic chamber 33a of the pressure-sensitive valve 103 has the oil passage 1
31 is connected to the pressure-sensitive oil chamber 19 of the pressure-sensitive cylinder 9,
The air guide chamber 51a is connected to the air supply source R. Also,
The air guide chamber 51b of the pressure reducing valve 105 is also connected to the air supply source R. Next, the operation of the pressure circuit 102 will be described.

When the work W is attached to the hook 11 of the work holder 7, the load of the work W is reduced by the pressure sensitive cylinder 9
Is reduced to reduce the volume of the pressure-sensitive oil chamber 19, so that a hydraulic pressure is generated in the pressure-sensitive oil chamber 19 in accordance with the load of the work. This oil pressure is guided to the hydraulic chamber 33a of the pressure sensitive valve 103 by the oil passage 131, and the pressure of the hydraulic chamber 33a rises to the pressure of the pressure sensitive oil chamber 19. As a result, the valve body 5
3a is lowered, and the pressurized air flows into the ventilation chamber 49a from the air guiding chamber 51a. The pressurized air that has flowed into the ventilation chamber 49a is supplied to the diaphragm chamber 33b of the pressure reducing valve 105 and the adjusting valve 10.
9 into the diaphragm chamber 113 and the pressure sensing chamber 39c of the relief valve 107.

In the pressure reducing valve 105, the diaphragm chamber 33b
The valve body 53b is lowered by the pressure increase of the air guide chamber 5
1b communicates with the ventilation chamber 49b. As a result, pressurized air from the air supply source R passes through the pressure reducing valve 105 and flows into the auxiliary air supply chamber 121 of the adjustment valve 109.

As is apparent from the configuration shown, the pressure reducing valve 1
In 05, when the pressure in the pressure sensing chamber 39b becomes higher than the pressure in the diaphragm chamber 33b by an amount corresponding to the urging force of the correction spring 45b, the receiving plate 35b is set to the neutral position and the valve is closed. Further, the pressure of the pressure sensing chamber 39b is increased by the diaphragm chamber 33b.
If the pressure is inferior to the sum of the biasing force of the correction spring 45b and the pressure, the pressure reducing valve 105 is opened. That is, the pressure reducing valve 10
The secondary pressure of No. 5 is higher than the secondary pressure of the pressure-sensitive valve 103 introduced into the diaphragm chamber 33b by a pressure corresponding to the urging force of the correction spring 45b. Accordingly, the pressure in the sub-supply chamber 121 of the regulating valve 109 to which the secondary pressure of the pressure reducing valve 105 is supplied is also higher than the secondary pressure of the pressure-sensitive valve 103 by a pressure corresponding to the urging force of the correction spring 45b. Have been.

In the adjusting valve 109, the diaphragm chamber 113
The valve body 117 is lowered by the pressurized air flowing into the sub-supply chamber 121 and the sub-pressure regulating chamber 119 are communicated with each other. 1
After passing through 19, it flows out to the pressure regulating piston chamber 24 side of the main valve 6.

This air is blocked by the needle valve 129 from flowing out to the downstream side. As a result, needle valve 1
Since the pressure on the upstream side of 29 rises, the pressure regulating piston chamber 2
The pressure of 4 rises. Since the pressure adjusting piston 20 descends due to the pressure increase in the pressure adjusting piston chamber 24, the stem 26
Also descends. Thereby, the air supply valve body 12 is lowered, and the air supply chamber 10 and the pressure regulation chamber 8 are communicated. Then, the pressurized air from the air supply source R flows from the air supply chamber 10 through the pressure adjusting chamber 8 into the working chamber 4 of the cylinder C.

The pressure in the working chamber 4 acts as a force for raising the piston P. This force acts on the pressure-sensitive piston 13 via the rod 3. The force for displacing the pressure-sensitive piston 13 acts on the pressure-sensitive cylinder 9 via the oil pressure in the pressure-sensitive oil chamber 19. After all, the force for raising the piston P works as the force for raising the work W.

When the pressure in the working chamber 4 rises, the pressure in the control chamber 22 communicating therewith also rises. This control room 22
Pressure acts as a force to push up the pressure adjustment piston 20. When the pressure in the sub-control chamber 115 of the regulating valve 109 communicating with the control chamber 22 increases, the diaphragm 11
1 is displaced to the diaphragm chamber 113 side, and the valve body 117 cuts off the communication between the sub-pressure regulating chamber 119 and the sub-supply chamber 121. As a result, the supply of the pressurized air to the pressure adjusting piston chamber 24 is stopped.

When the pressure in the control chamber 22 is superior to the pressure in the pressure regulating piston chamber 24, the pressure regulating piston 20 is raised, the air supply valve body 12 is set to the closed position, and the pressure regulating chamber 8 and the working chamber 4 are fed. The supply of pressurized air is stopped. If the pressure in the control chamber 22 is higher, the pressure adjustment piston 20 is raised beyond the neutral position, the exhaust valve body 16 is set to the open position, and the compressed air in the pressure adjustment chamber 8 and the working chamber 4 is discharged. Therefore, the pressure in the control chamber 22 decreases. When the pressure in the control chamber 22 and the pressure in the pressure adjustment piston chamber 24 are balanced, the pressure adjustment piston 20 is set to the neutral position, and the pressure adjustment chamber 8 and the working chamber 4 are not supplied with air. The exhaust from the working chamber 8 and the working chamber 4 is not performed.

On the other hand, in the relief valve 107, the diaphragm chamber 33 into which the pressure on the downstream side of the needle valve 129 is introduced.
If the force for pushing down the diaphragm 37c by the pressure of the pressure c and the urging force of the correction spring 45c is larger than the force for pushing up the diaphragm 37c by the pressure of the pressure sensing chamber 39c, the valve body 53c is set to the open position and the downstream of the needle valve 129. Discharge side air to atmosphere. If the force for pushing up the diaphragm 37c is excellent in pushing down, the valve element 53c is set to the closed position. In other words, based on a state in which the pressure of the diaphragm chamber 33c is lower than the pressure of the pressure sensing chamber 39c by an amount corresponding to the urging force of the correction spring 45c, if the pressure of the diaphragm chamber 33c is higher than that, the valve body 53c is the open position. If the pressure in the diaphragm chamber 33c is lower than that, the valve body 53c is set to the closed position.

Therefore, the pressure on the downstream side of the needle valve 129 is lower than the pressure in the pressure sensing chamber 39c by an amount commensurate with the urging force of the urging spring 45c. By the way, since the pressure in the pressure-sensitive chamber 39c is the secondary pressure of the pressure-sensitive valve 103, the pressure downstream of the needle valve 129 is
The pressure is lower than the secondary pressure of No. 3 by an amount corresponding to the urging force of the urging spring 45c. Then, as described above, the pressure on the upstream side of the needle valve 129 (= the pressure in the pressure-regulating piston chamber 24) is made substantially equal to the secondary pressure of the pressure-sensitive valve 103. And the process until the pressure in the control room 22 is balanced, and also thereafter.
Release from the needle valve 129 (outflow to the relief valve 107 side) is continued.

In this way, since there is air that passes through the needle valve 129 and flows out to the downstream side of the needle valve 129,
The pressure in the pressure adjustment piston chamber 24 will gradually decrease. Then, the pressure balance between the pressure adjustment piston chamber 24 and the control chamber 22 is broken, and the pressure adjustment piston 20 rises. As a result, the exhaust valve body 16 is set to the open position, and the pressurized air in the pressure regulation chamber 8 is discharged, so that the pressure in the control chamber 22 decreases and the pressure in the sub control chamber 115 also decreases. Then, the valve body 11 again
Since the sub-pressure regulating chamber 119 communicates with the sub-supply chamber 121, the pressure in the pressure regulating piston chamber 24 is restored.

As described above, the pressure in the pressure regulating piston chamber 24 is made substantially constant by opening and closing the valve body 117, and the pressure in the control chamber 22 and the pressure in the pressure regulating piston chamber 24 are balanced. When this balance is established, the pressure in the working chamber 4 becomes substantially constant, and the piston P is in a balanced state.

Assuming that the pressure-receiving areas of the pressure-adjusting piston chamber 24 side and the control chamber 22 side of the pressure-adjusting piston 20 are equal, when this balance state is established, the pressure-adjusting piston chamber 24
Is equal to the pressure in the control chamber 22, and the pressure in the control chamber 22 is equal to the pressure in the sub-control chamber 115 of the regulating valve 109. The pressure in the sub control chamber 115 is balanced with the pressure in the diaphragm chamber 113. The pressure in the diaphragm chamber 113 is equal to the pressure in the pressure-sensitive chamber 39a of the pressure-sensitive valve 103,
9a is the pressure of the hydraulic chamber 33a, that is, the pressure-sensitive oil chamber 19
Balance with pressure. After all, the pressure adjustment piston chamber 24
Is in accordance with the pressure of the pressure-sensitive oil chamber 19, that is, the load of the work W, and the piston P is in a balanced state. As described above, according to the pressure circuit 102, the piston P of the cylinder device 60 can be brought into a balanced state without performing a special adjusting operation according to the work W.

After the piston P is balanced in this way, when an external force is applied to the handle 5 to raise the piston P together with the work W, the pressure in the working chamber 4 decreases and the sub-control chamber 115 and the control chamber are controlled. Since the pressure in the chamber 22 also decreases, the regulating valve 109 opens and the air on the side of the auxiliary air supply chamber 121 flows into the pressure regulating piston chamber 24 to push down the pressure regulating piston 20.

At this time, the air supplied to the sub air supply chamber 121 is more commensurate with the biasing force of the correction spring 45b than the pressure on the pressure regulating piston chamber 24 side, which is substantially equal to the secondary pressure of the pressure sensitive valve 103. Since the pressure is increased by the pressure, the pressure difference between the pressure adjusting piston chamber 24 side and the auxiliary air supply chamber 121 side is small. Therefore, the air on the side of the auxiliary air supply chamber 121 does not flow into the pressure regulating piston chamber 24 all at once due to the opening of the regulating valve 109, and the pressure regulating piston 20 is not pushed all at once. Therefore, the high-pressure air from the air supply source R does not suddenly flow into the working chamber 4. Therefore, the sudden rise of the piston P and the work W due to the rapid flow of the high-pressure air into the working chamber 4 is avoided.

However, since the inflow of air into the pressure-adjusting piston chamber 24 is not obstructed, the piston P and the work W can be smoothly raised. When the piston P is lowered by an external force from the equilibrium state, the sub-control chamber 115 and the control chamber 22
Is also increased, so that the regulating valve 109 is closed. At the same time, the pressure adjustment piston 20 is pushed up, and the pressure in the pressure adjustment piston chamber 24 increases according to the displacement amount of the pressure adjustment piston 20. When the pressure on the pressure adjustment piston chamber 24 side rises, the outflow of air from the needle valve 129 is promoted.

However, as described above, the relief valve 1
07, the pressure on the downstream side of the needle valve 129 is increased by an amount corresponding to the urging force of the urging spring 45c.
Since the pressure is lower than the pressure on the upstream side of 29,
Air does not suddenly flow out of the needle valve 129, and air in the pressure adjusting piston chamber 24 is not excessively discharged. As a result, it is possible to prevent the exhaust valve body 16 from being pulled up at once by a sudden rise of the pressure adjustment piston 20, that is, a sudden rise of the stem 26. Therefore, the pressure regulation chamber 8
Is not suddenly discharged, and the piston P and the work W do not suddenly drop due to a sudden drop in the pressure of the working chamber 4.

However, since the exhaust from the pressure regulating piston chamber 24 is not obstructed, the smooth lowering of the piston P and the work W is ensured. As described above, according to the pressure circuit 102 of the present specific example, when the external force is exerted on the piston P in the balanced state, the smooth elevation of the piston P and the work W is ensured, and the piston P and the work W are rapidly moved. Lifting is prevented.

In the pressure circuit 102 of this specific example, if an external force is applied to the rod 3 via the handle 5, the work W can be moved up and down with a slight force. In addition, the oil path 131
By interposing a two-way valve on the workpiece and shutting off the oil passage 131 by the two-way valve after the balance state is reached, it is possible to exert an external force on the work W itself to move it up and down.

Further, since the pressure circuit 102 is provided with the pressure reducing valve 105 and the relief valve 107 as the above-mentioned circuit configuration, the adjusting valve irrespective of the supply pressure of the air supply source R and the weight of the work. The differential pressure between the primary pressure and the secondary pressure of 109 is constant, and the differential pressure between the upstream side and the downstream side of the needle valve 129 is also constant. Therefore, when the external force is applied to the piston P in a balanced state, the piston P and the work W are smoothly moved up and down, and the piston P and the work W are prevented from being moved up and down suddenly.

When the pressure in the pressure-sensitive oil chamber 19 becomes lower than the pressure in the working chamber 4 because the pressure-sensitive area X of the pressure-sensitive piston 13 is larger than the pressure-receiving area Y of the piston P, for example, If the biasing force of the correction spring 45a is increased by the adjusting stem 41a of the pressure valve 103, the pressure circuit 102 can be operated as described above.

Further, when the pressure in the pressure-sensitive oil chamber 19 becomes higher than the pressure in the working chamber 4 due to, for example, the pressure-sensitive area X of the pressure-sensitive piston 13 being smaller than the pressure-receiving area Y of the piston P, the needle is The pressure circuit 102 can be operated as described above by increasing the opening degree of the valve 127 and increasing the exhaust velocity from there.

As described above, the work P can be moved up and down by placing the piston P in a balanced state according to the load of the work W and applying a very small external force. next,
A case where the piston P approaches the descending end 71 or the ascending end 72 as the work W moves up and down will be described.

For example, when an external force is applied via the handle 5 to lower the piston P, the pressure sensitive cylinder 9 is also lowered together with the piston P. Then, the sliding rod 63 fixed to the pressure sensitive cylinder 9 also descends, the sliding ring 64 eventually contacts the descending stopper 62, and the descending displacement of the sliding rod 63 is prevented. At this time, the sliding rod 63 exerts a downward force due to the inertia of the work W or the like. This force acts as a force to compressively deform the compression coil spring 66. The compression coil spring 66 prevents the impact caused by the lowering of the sliding rod 63 due to the deformation. And the sliding rod 63
Is prevented from descending, the piston P moves downward 71
The descent of the pressure sensitive cylinder 9 and the work W is stopped before the contact with the. Further, the load of the pressure sensitive cylinder 9 and the work W is applied to the lowering stopper 6 via the sliding rod 63.
Supported by 2.

When the loads of the pressure sensitive cylinder 9 and the work W are supported by the lowering stopper 62, these loads are not exerted on the oil in the pressure sensitive oil chamber 19, so that no hydraulic pressure is generated in the pressure sensitive oil chamber 19. Then, the pressure sensitive valve 103 is closed and the pressure reducing valve 105 and the adjusting valve 109 are also closed, so that the pressure adjusting piston 20 of the main valve 6 is not driven downward, and a new pressure is added to the working chamber 4. No pressurized air is supplied. Therefore, the piston P is not driven upward and the bouncing phenomenon does not occur.

On the other hand, when the piston P is raised to the vicinity of the rising end 72, the sliding ring 65 hits the rising stopper 61 before the piston P reaches the rising end 72, so that the sliding rod 63 moves upward. Be blocked. As a result, the pressure sensitive cylinder 9 and the work W are also prevented from rising. At this time, the compression coil spring 66 prevents an impact as in the case of the descending operation.

Thus, the pressure sensitive cylinder 9 and the work W
If the piston P is not blocked,
When the ascending end 72 of the
The hydraulic pressure in the pressure-sensitive oil chamber 19 decreases due to the inertia of the. Then
Along with this, the pressure sensitive valve 103, the pressure reducing valve 105, and the adjusting valve 109 are closed, and the pressure adjusting piston chamber 2 of the main valve 6 is closed.
The pressure-reducing piston 20 is driven to rise due to the pressure decrease of 4 and is exhausted from the working chamber 4, so that the piston P instantaneously descends.

However, since the rise of the pressure sensitive cylinder 9 and the work W is restricted as described above, the influence of the inertia of the work W does not affect the pressure sensitive oil chamber 19.
Therefore, the lowering of the piston P as described above does not occur. The same effect can be obtained by incorporating the cylinder device 60 of the specific example into the pressure circuit of the conventional example shown in FIG.

Although the embodiments of the present invention have been described according to the specific examples, the present invention is not limited to the specific examples and various modifications can be made without departing from the scope of the present invention. Needless to say. For example, in the specific example, the pressure sensing oil chamber 19 and the pressure sensing piston 13 are provided as load detecting means, and the pressure of the working chamber 4 is adjusted according to the hydraulic pressure generated in the pressure sensing oil chamber 19, but the hydraulic pressure is It is also possible to employ a configuration in which sensors such as a load cell are used as the configuration to be used or load detecting means.

The configuration of the pressure circuit is not limited to the configuration of this specific example. In the specific example, the sliding ring 64 and the sliding ring 6
5 is due to the presence of the compression coil spring 66,
Although not in contact with each other, sleeves that project toward the other side and slide on the outer periphery of the guide shaft 69 are provided on both the sliding ring 64 and the sliding ring 65, and the compression coil spring 66
Is shortened and deformed by a certain amount, the sleeves come into contact with each other to stop the sliding rod 63 from moving up and down,
It is also possible to provide the above-mentioned sleeve only on one of the slide ring 64 and the slide ring 65 and similarly stop the lifting of the sliding rod 63.

[0073]

As described above, according to the pressure circuit of the first aspect, the cylinder device including the piston that receives the load of the work and the cylinder that slidably accommodates the piston, and the load of the work. In a pressure circuit including load detecting means for detecting and a supply / discharge means for supplying / discharging the pressure gas for driving the piston to / from the cylinder device according to the detected load, in the vicinity of the lower end of the piston. Bound phenomenon can be prevented.

According to the pressure circuit of the second aspect, the effect of the configuration of the first aspect can be further ensured. According to the pressure circuit of the third aspect, it is possible to prevent the momentary lowering of the piston near the rising end.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of a pressure circuit of a specific example.

FIG. 2 is an explanatory diagram of a configuration of a conventional pressure circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pressure circuit, 3 ... Rod, 4 ... Working chamber, 5 ... Handle, 6 ... Main valve (supply / discharge means), 7 ... Work holding body (load detection means) , 9 ... Pressure-sensitive cylinder (load detecting means), 11 ... Hook, 13 ... Pressure-sensitive piston (load detecting means), 15 ... Oil passage port, 17 ... Vent port, 19. ..Pressure-sensitive oil chamber (load detecting means), 60 ... Cylinder device, 61 ... Ascending stopper (rising restricting means), 62 ... Falling stopper (supporting means, descending restricting means), 63 ... Sliding rod (supporting means, lowering restricting means, rising restricting means), 64 ... Sliding ring (supporting means, lowering restricting means, rising restricting means), 65 ... Sliding ring (supporting means, lowering restricting means, Ascending regulation means), 66 ... Compression coil spring (supporting means, descending regulation means,
68. Head (supporting means, lowering restricting means, rising restricting means), 69 ... Guide shaft (supporting means, lowering restricting means, rising restricting means), 71 ... Lowering end, 72 ... Ascending end, 102 ... Pressure circuit, 103 ... Pressure sensitive valve, 105 ... Pressure reducing valve, 107 ... Relief valve, 109 ... Regulating valve, 125 ... Orifice, 127. ..Needle valve, 129 ... Needle valve, 131 ... Oil path, C ... Cylinder, P ... Piston, R ... Air supply source, W ... Work.

Claims (3)

[Claims] 1. A cylinder device comprising a piston for receiving a load of a work and a cylinder for slidably accommodating the piston, and load detecting means for detecting the load of the work,
A pressure circuit that adjusts a gas pressure for driving the piston according to the detected load, when the piston is displaced in a direction of lowering the work, the lower end of the piston and the cylinder A pressure circuit comprising support means for supporting the load of the work when the distance between the work piece and the work piece becomes a predetermined distance or less. 2. The pressure circuit according to claim 1, further comprising a descent control means for restricting the descent of the work when the distance between the piston and the descent end of the cylinder reaches a predetermined distance. circuit. 3. The pressure circuit according to claim 1, further comprising an ascending restricting means for restricting an ascending of the work when a distance between the piston and an ascending end of the cylinder reaches a predetermined distance. Pressure circuit to do.