JP2009264574A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To resolve a problem in a conventional air type shock absorber wherein an air hole is provided in a piston to prevent a rear side from becoming vacuum, while causing unstable operation due to this, and being difficult to correspond to various purposes of temporarily stopping restoration after seating due to immediate start of the restoration action when pressing of a movable body is gone. <P>SOLUTION: By abolishing the air hole of conventional structure, newly providing an isolated hollow part in the rear side of the piston, and providing a pressure regulation check valve in the piston, the air type shock absorber can carry out positive operation and seating, and it can maintain a stopped state. Since operation is stable even after long time use, there is no need for repair time. By a time adjusting device, restoration of a piston shaft can be set at a timing not interfering with operation of the movable body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a pneumatic shock absorber that absorbs a shock of a moving body that occurs when a moving body such as a workpiece shifts from its moving state to a stopped state.

The conventional shock absorber absorbs the impact by the pushing of the piston that is pushed by the moving body and moves inside the cylinder. However, there is a case where the seating of the moving body becomes incomplete due to the strong repulsive force of the return spring. In order to cope with such applications, the present applicant created a shock absorber that sends air into the cylinder without using the force of the return spring to return the piston and the piston shaft to the state before compression, and applied for a patent. did.

FIG. 8 is a cross-sectional view showing an example of a conventional shock absorber for returning the piston and the piston shaft with air, and the contents thereof will be briefly described below mainly with respect to the operation thereof.
In FIG. 8, the piston 53 pressed by the moving body W compresses the air in the cylinder 51 to absorb the impact, and the compressed air gradually becomes a gap narrowed by the flow rate adjusting shaft 63 of the speed controller 61. 64, and further flows back through a solenoid valve 71 to a pneumatic pressure source (not shown) connected to the pressure source side tube 74 to be absorbed.

A small amount of compressed air is circulated through the air vent hole 53a so that the bearing 53 side of the piston 53 is not in a vacuum state.
In this case, providing an air passage that communicates with the outside of the shock absorber so that the bearing side of the piston is not in a vacuum state is not applicable because of contamination in the vicinity of the shock absorber.

Further, when the piston 53 pushes the compression coil spring 57 with a small stroke and the actuator 56a of the push switch by the pressing force of the moving body W, the push switch 56 is turned off, the electromagnetic valve 71 is switched, and the compressed air is The piston 53 is seated by being discharged to the outside. When the pressing force of the moving body W on the piston shaft 52 is lost, the piston 53 is slightly returned by the reaction force of the coil spring 57, so that the push switch 56 is turned on and the electromagnetic valve 71 returns to the state shown in FIG. Since the high-pressure air from the air pressure source (not shown in the drawing) pushes open the check valve 65 of the speed controller 61 and rapidly flows into the cylinder 51 through the flow path 66, the piston 53 returns quickly.

Patent No. 3686916, JP 2000-257658 A

Indication of invention

Problems to be solved by the invention

The conventional pneumatic shock absorber described above has a feature that makes it easy to sit down because it performs return operation with air pressure without using a return spring with a large repulsive force, but the back side of the piston is not in a vacuum state As described above, since a part of the compressed air is recirculated through the orifice by providing an air vent hole in the piston, the operation may be unstable. In the above-mentioned patent, when removing the moving body seated by pressing the piston, if it is desired to stop the returning operation until the moving body leaves, the coil spring having a small stroke and the push At the same time, the solenoid valve returns to send air into the cylinder, and the piston shaft starts the return operation, which disturbs the movement of the moving body.
The present invention solves these problems, realizes stable shock absorption, reliable maintenance of the seated state, and piston return at a desired timing, and the shock absorber operates in accordance with the movement of the moving body. It is for the purpose.

Means to solve the problem

In order to achieve the above-mentioned object, the present invention eliminates the air vent hole 53a of the piston of FIG. 8, newly provides a cavity part isolated on the piston bearing side in the cylinder, and communicates with the outside on the bearing side cavity part of the piston. Even if there is no air passage, by setting the air pressure of the cavity on the bearing side to a value that does not fall below atmospheric pressure in the seated state of the piston, the piston can be reliably maintained in the seated state without being pushed back to the bearing side. did.

In addition, a pressure adjustment check valve is provided on the piston, and the air pressure exceeding the set value is automatically adjusted when the piston is seated so that a small amount of air leakage generated from the piston seal does not accumulate even during long-term operation. The check valve is discharged through a solenoid valve located away from the place where the shock absorber is used, allowing the shock absorption and return operations to continue at a stable set pressure.

Further, the compression coil spring 57 and the piston stopper 58 with a small stroke in FIG. 8 are abolished, and the switch means for controlling the solenoid 73 is renewed, and when the piston is seated by the pressing of the moving body, the coil spring with the small stroke is pushed. Instead, the push switch was turned off to exhaust the compressed air in the cylinder, and the piston shaft was stopped reliably. In addition, even if the moving body is separated, the piston shaft is stopped by the time adjusting device until a desired time, and the piston shaft is returned at a desired timing.

The invention's effect

As described above, the pneumatic shock absorber of the present invention ensures the absorption and seating of the shock of the moving body and does not accumulate air leakage from the piston seal. And stable. Therefore, productivity is improved without taking repair time. Furthermore, it is possible to maintain the stopped state at the seating position of the piston and the piston shaft, and the return can be performed at a desired timing, so that the moving body moves from the seating until it is removed. Does not interfere with body operation.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 shows a state before being pressed by the moving body W. At this time, the front cavity 10 of the cylinder 1 is in a state filled with the pressure air sent from the air pressure source 18 through the electromagnetic valve 21.

FIG. 2 shows a state in which the piston 3 pressed by the moving body W compresses the compressed air in the front cavity 10 and absorbs an impact while increasing the drag against the moving body W.
FIG. 3 shows a seated state where the piston 3 is pushed into the moving body W and reaches the stroke limit.

FIG. 4 shows a state in which the piston shaft 2 is stopped while the moving body W is removed even when the pressing force of the moving body W disappears.
FIG. 5 shows a state where the solenoid valve is operated at a desired timing and the piston 3 and the piston shaft 2 are rapidly returned to the state shown in FIG.

FIG. 6 is a detailed view of the pressure regulating check valve 30 incorporated in the piston 3.
When the piston 3 slides, the piston seal 4 is rubbed through the high pressure front cavity portion 10 into the bearing side cavity portion 9 to leak a small amount of air pressure, which accumulates when operated for a long time, and the bearing side cavity portion 9 is set. If the air pressure exceeds the value, it will hinder operation.
In the state of FIGS. 3 and 4, the pressure regulating check valve 30 incorporated in the piston 3 has an air pressure in the front hole 35 leading to the front cavity 10, so that the air pressure in the bearing cavity 9 is set. When the pressure exceeds the value, the air pressure from the bearing side hole 34 compresses the valve main body 31 and the pressure regulating spring 33 and the pressure regulating check valve 30 is opened. 3 and (AR) of the electromagnetic valve 21 shown in FIG.
1, 2 and 5, since the compressed air in the front cavity 10 is higher than the air pressure in the bearing cavity 9, the pressure regulating check valve 30 is closed by the valve body 31 being pressed against the seal 32. The air pressure from the pressure regulating check valve 30 is not entered and exited.

FIG. 7 shows a configuration of a second embodiment in which a switch 46 is attached to the outside of the cylinder 1 instead of the push switch 6.

1 to 7, reference numeral 21 denotes an electromagnetic valve. When the solenoid 23 is energized, the air passage is (PA) or (AP) at the position 21a. When the solenoid 23 is not energized, the air passage is (A-R) at the position 21b. R is an exhaust port to the atmosphere.

Z ₂ is a current controller for controlling the energization of the solenoid 23, Z ₁ is the time adjustment unit originating an ON signal to the set time and set the count time. Incidentally, electrification control apparatus Z ₂ is OFF the energization of the instant solenoid 23 when the push switch 6 is turned OFF, to ON the power supply to the solenoid 23 when receiving the ON signal from the time adjustment device Z ₁ To do.

Hereinafter, the operation of the above configuration will be described.
As shown in FIG. 2, when the moving body W collides and pushes the piston shaft 2, the piston 3 with the piston seal 4 slides inside the cylinder 1, and the pressure air in the front cavity 10 is changed to the piston 3. , The pressure in the bearing-side cavity 9 expands, causing strong drag on the piston 3 and the piston shaft 2 and absorbing the impact of the moving body W. At this time, the high-pressure compressed air that has been pressed by the moving body W and increased in pressure in the front cavity portion 10 sequentially passes through the gap at the tip of the flow rate adjusting shaft 13, and (AP) of the air tube 19 and the electromagnetic valve. To be absorbed by the air pressure source 18.

As shown in FIG. 3, when the piston 3 is further pushed to the mobile W is seated reached the stroke limit, the actuator 6a displaces the push switch 6 is turned OFF, the energization control unit Z ₂ Since the energization of the solenoid valve 21 to the solenoid 23 is turned off, the solenoid valve 21 is in the position 21b, the air passage becomes (AR), and the compression remaining in the front cavity 10 of the cylinder 1 remains. Air is discharged from the electromagnetic valve 21 to the outside. At the same time the push switch 6 is OFF, the time adjustment device Z _1, it starts counting the set time. Further, in the state of FIG. 3, when a small amount of air leakage from the sliding surface of the piston seal 4 accumulates and the air pressure in the bearing side cavity 9 is higher than the set air pressure, the excess air pressure Is discharged from the pressure regulating check valve 30 of the piston 3 through the gap at the tip of the flow rate adjusting shaft 13 and through the air tube 19 from the electromagnetic valve 21, so that the bearing-side cavity 9 is kept at the set air pressure. It is.

Further, as shown in FIG. 4, even when the pressing force to the piston shaft 2 of the moving body W is lost, the energization to the solenoid 23 remains OFF and the electromagnetic valve 21 maintains the position (A-R). Since the piston shaft 2 maintains the seated state, the moving body W can move without being obstructed.

Then, reaching the count is set to count the time adjustment device Z ₁ time, upon exiting the instruction ON from the time adjustment device Z _1, electrification control apparatus Z ₂ is switched, energization ON of the solenoid 23 Thus, the electromagnetic valve 21 is in the state of (PA) at the position 21a shown in FIG. 5, and the compressed air from the air pressure source 18 flows through the electromagnetic valve 21 and the air tube 19 in the direction of the arrow. Since the check valve 15 is opened by this flow, the compressed air flows into the front cavity 10 of the cylinder 1 without being throttled, and the piston 3 quickly returns to the state shown in FIG.

Next, the operation of the configuration of the second embodiment shown in FIG. 7 will be described.
In the case of FIGS. 1 to 5, the push switch 6 is fixed to the inner part of the cylinder 1, but in the case of FIG. 7, the switch 46 is attached to the outside of the cylinder 1.
Other than setting the time count time adjustment device Z _1, even in embodiments of the second embodiment, FIG. 1 described above, common to the operation of FIGS. 2 and 5, the same that configuration also identical ones Symbols are attached, duplicated descriptions are omitted, and only the differences are described.
The aforementioned FIG 4, in the case of FIG. 5, the time adjustment device Z _1, the push switch 6 is time set to start counting at the moment when set to OFF.
Second in the case of the example embodiment, the time adjustment device Z _1, and a method for time setting so that the switch 46 starts counting at the moment when turned OFF, the switch 46 is ON as shown in FIG. 7 contrast There is a method to set the time to start counting at the moment when it becomes. Either of them may be selected. In FIG. 7, a method of switch 46 instantaneously in time adjustment device Z ₁ in an OFF is the time set to start counting, omitted since it is common in the case of FIG. 4, FIG. 5 of the above Only the operation of the method for setting the time so as to start counting at the moment when the switch 46 is turned on will be described below.

As shown in FIG. 7, when the moving body W reaches the seating position, the switch 46 is pushed and turned off. Since energization in response to the solenoids 23 of the power supply control unit Z ₂ is OFF, the solenoid valve 21 is in the position of 21b, the residual compressed air of the front cavity 10 of the solenoid valve 21 (A-R ) Released from the passageway into the atmosphere. Accordingly, even when the pressing force of the moving body W on the piston shaft 2 is lost, the return force from the front cavity 10 side does not act on the piston 3, and the piston 3 and the piston shaft 2 maintain the seated state.
Next, when the moving body W leaves this position will switch 46 is ON, the time adjustment device Z ₁ in the signal starts counting, ON signals to the conduction control device Z ₂ when it becomes the count time setting the feed, power supply to the power supply control unit Z ₂ is switching behalf solenoid 23 is turned oN in response thereto. The position of the solenoid valve 21 is switched to 21a, the compressed air from the air pressure source 18 flows into the front cavity 10 of the cylinder 1, and the piston 3 returns quickly.

Sectional drawing which shows the structure of embodiment of this invention Sectional drawing which shows the state which operate | moves while absorbing the shock of a moving body same as the above Same as above, sectional view showing the state where the piston shaft reaches the stroke limit Same as above, even if the moving body loses pressing force, the cross section showing the state where the piston shaft is stopped until the desired time Same as above, a cross-sectional view showing a state of returning after a desired time has elapsed Cross-sectional enlarged view of pressure regulating check valve Sectional drawing which shows the structure of 2nd embodiment of this invention. The block diagram which shows the state which piston is going to move by being pushed by the mobile body in embodiment of a prior art example

Explanation of symbols

1. Cylinder 19 Air tube 2. Piston shaft 21 Solenoid valve 3. Piston 21a Position of solenoid valve (PA) 4. Piston seal 21b Solenoid valve (AR) position Bearing 22. Power supply 6. Push switch 23. Solenoid 6a. Actuator 30. 6. Pressure regulating check valve Cap 31. Valve body 8. Piston stopper 32. Seal 9. Bearing side cavity 33. Pressure regulating spring 10. Front cavity 34. 10. Bearing side hole Seal 35. Front hole 12a. Packing 46. Switch 12b, packing Pressure source side air port 13. Flow rate adjusting shaft A. Air port 14. Flow rate adjustment hole 14. Air opening opened to the outside Check valve W. Mobile object 17. Air passage Z ₁ hour adjustment device 18. Air pressure source Z ₂ electrification control apparatus

Claims (3)

The compression pressure of the air generated in the cavity on the opposite side of the piston shaft bearing by the pushing of the piston and the piston shaft, which is pressed by the moving body and moves in the cylinder, is used as a drag force against the impact of the moving body. In the pneumatic shock absorber that performs pneumatically without using a spring when returning the piston shaft, an air pressure isolated volume set in the bearing side cavity is provided in the restored state, and the piston is pushed in and seated Even in this state, the bearing-side cavity does not become an air pressure lower than the atmospheric pressure, and the seating state is maintained until the air pressure for returning is supplied to the opposite side of the bearing of the piston. Pneumatic shock absorber. When a pressure regulating check valve is provided on the piston, and a small amount of air leaks from the piston seal in the bearing cavity of the piston accumulates over a long period of time and exceeds the set air pressure. The excess air pressure is discharged from the air intake port of the shock absorber in the sitting state to prevent accumulation of excess air pressure in the bearing side cavity, and stable shock absorption and return operation are continued. The pneumatic shock absorber according to 1. A time adjusting device is provided in the switch means of the pneumatic circuit for automatically operating the pneumatic shock absorber, and the piston shaft is completely stopped while the piston is seated on the bottom of the cylinder. 2. The pneumatic shock absorber according to claim 1, wherein the return is adjusted by time and returned by air pressure at a desired timing.

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