JPH051706Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention [Industrial Application Field] The present invention relates to a shock absorber, and more specifically, it applies a biasing force against the movement of the piston rod near the end of its movement when the piston moves in one direction. This invention relates to a shock absorber equipped with a cushion mechanism.

[Prior Art] Conventionally, pneumatic or hydraulic cylinders have been known to be provided with a cushion mechanism for the purpose of absorbing inertia force at the end of a piston's stroke. Such a cushion mechanism usually includes a throttle mechanism that throttles the discharge of fluid (air or oil) accompanying the movement of the cylinder near the end of the piston's stroke, thereby slowing down the movement of the piston and preventing impact.

[Problems to be Solved by the Invention] However, a shock absorber equipped with such a cushion mechanism has a problem in that desired operation may not be obtained depending on the magnitude of the load attached to the piston rod. In other words, if you want to obtain a sufficient buffering effect even under conditions of high inertial energy, such as a large load and a high moving speed,
The fluid discharge must be fairly restricted; if it is too restricted, the reaction force may cause the piston to rebound in the opposite direction of its movement. On the other hand, if the fluid discharge is not restricted too much, a sufficient buffering effect cannot be obtained.

The purpose of the shock absorbing device of the present invention is to solve the above-mentioned problems and to prevent the piston from bouncing back and to realize a sufficient shock absorbing effect.

Structure of the invention The structure of the invention that achieves the above object will be explained below.

[Means for Solving the Problems] The shock absorber of the present invention is provided in a cylinder device that drives a piston by a pressure balance between chambers on both sides of the piston, and when the piston moves in at least one direction, the shock absorber is provided with In a shock absorber equipped with a cushion mechanism that applies a biasing force against the piston rod, a clutch body having an internal tapered surface expanding in the direction of movement of the piston rod is externally fitted onto the piston rod, and a steel ball is inserted into the clutch body so that the piston rod is The present invention is characterized by comprising: a one-way clutch that is held in contact with the steel ball; and a clutch-free mechanism that releases the one-way clutch by releasing the contact between the steel ball and the clutch body.

[Operation] When the shock absorber of the present invention having the above-mentioned configuration moves the piston in one direction, it receives an urging force from the cushion mechanism that resists the movement just before the end of the movement.
Furthermore, even if the piston rod attempts to move in the opposite direction to the direction of movement due to this biasing force, the one-way clutch prevents the movement. That is,
When the piston rod tries to move contrary to its original direction of movement, the steel ball inside the clutch body that is in contact with the piston rod is strongly pressed in the direction of the piston rod by the tapered surface inside the clutch body, and it bites into the piston rod. It prevents its movement. When the one-way clutch is released by the clutch-free mechanism, the piston rod can be moved in the opposite direction.

[Example] In order to further clarify the structure and operation of the present invention described above, preferred embodiments of the shock absorbing device of the present invention will be described below. FIG. 1 is a cross-sectional view showing the structure of a pneumatic cylinder with a shock absorber as an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the same in a state in which the clutch is released.

As shown in the figure, this pneumatic cylinder with a shock absorber includes first and second cylinders 3 and 5 connected by a cushion mechanism 1;
A head cover 7 and a rod cover 9 that close the ends of the cylinders 3 and 5, a piston rod 10 slidably inserted through the rod cover 9 and the cushion mechanism 1, and a first piston rod 10 of the piston rod 10.
The end inside the cylinder chamber 12 has a fixed piston 1
4. It consists of a one-way clutch section 20 provided within the second piston chamber 16, etc.

The first cylinder chamber 12 is divided into a first pressure chamber 21, a second pressure chamber 22, and a third pressure chamber 23 by the piston 14 and its stepped portion 14a, and the first pressure chamber 21 is provided in the head cover 7. On the other hand, the second pressure chamber 22 and the third pressure chamber 23 are connected to the pressure adjustment section 30 through a throttle 32 and a communication hole 27 provided in the cushion mechanism section 1, respectively. and forms an air circuit that drives the piston 14. Further, the second pressure chamber 22 is connected to the third pressure chamber 23 via the check valve 34.
It is also communicated to.

The pressure adjustment unit 30 moves the piston 14 and the piston rod 10 forward (moves in the direction of arrow F in FIG. 1).
In this case, the 3-port 2-position valves 37 and 38 are switched to connect the high pressure source 39 to the first pressure chamber 21.
The second and third pressure chambers are connected to the atmosphere through a speed control valve. As a result,
The piston 14 moves in the direction of arrow F due to the pressure balance between the two chambers, but the stepped portion 14 of the piston 14
From the time point a fits into the third pressure chamber 23 of the cushion mechanism 1, the moving speed of the piston 14 rapidly decreases. This is because the outflow of air in the second pressure chamber 22 is restricted by the throttle 32, and the second pressure chamber 22
This is because the internal pressure increases and the piston 14 receives a strong reaction force. Note that when the piston 14 is moved backward, the pressure adjustment section 30 adjusts the pressure in the first pressure chamber 2.
1. Reverse the pressure balance between the second pressure chamber 22 and the third pressure chamber 23. In this case, the pressure in the second pressure chamber 22 is reduced to the third pressure chamber 2 by the action of the check valve 34.
The pressure is almost the same as No. 3.

Next, the structure and function of the one-way clutch section 18 will be explained. The one-way clutch section 18 includes a clutch main body 43 having a housing section 41 that is slidably housed in the second cylinder 5 and whose inner periphery extends toward the rod cover 9, and a steel ball 45 that is housed in the housing section 41.
, a retainer 47 that holds the steel balls 45, and a compression spring 49 that biases the steel balls 45 in the direction of the cushion mechanism section 1 via the retainer 47. Retainer 4 that freely rotatably holds steel balls 45
7 is smaller than the opening of the storage portion 41 of the clutch body 43 and the steel ball 45 is larger, so when the one-way clutch 18 is moved in the direction of arrow F as shown in FIG. The force presses against the tapered portion 50 of the clutch body 43, and it also comes into contact with the outer peripheral surface of the piston rod 10.
Incidentally, the slope of the tapered portion 50 of the clutch body 43 is
It is set smaller than the friction angle with the steel ball 45.

Further, the clutch body 43 of the second piston chamber 16
Out of the space divided by , the side that communicates with the storage section 41 has a communication hole 52 provided in the cushion mechanism section 1, and the opposite side has a communication hole 54 provided in the rod cover 9. 4 ports 2
It is connected to a clutch actuation valve 55 which is a position valve. Of the other two ports of the clutch operating valve 55, one is open to the atmosphere and the other is connected to a pressure source 57.

In the configuration of the one-way clutch 18 described above,
When the clutch operating valve 55 is switched to position a shown in FIG. It comes into contact with. In this state, when the piston rod 10 moves (advances) in the direction of arrow F, the steel ball 45 can rotate freely, so the movement of the piston rod 10 is not restricted in any way. However, piston rod 1
0 tries to move in the direction of arrow B shown in FIG.
0 and strongly presses the piston rod 10 in the direction of its axial center, so the movement of the piston rod 10 is prevented.

On the other hand, when the clutch operating valve 55 is switched to position b, the clutch body 43 comes into contact with the cushion mechanism 1, as shown in FIG. In this state,
Since the retainer 47 controls the movement of the steel balls 45,
The steel ball 45 and the tapered portion 50 are spaced apart. If the steel ball 45 is spaced apart from the tapered portion 50, the piston rod 10 moves in either direction (forward or backward).
Since the piston rod 10 can rotate freely even when moving in the opposite direction, the movement of the piston rod 10 is not restricted in any way in either direction.

In the pneumatic cylinder equipped with a shock absorber according to the present embodiment described above, when moving the piston 14 in the direction of arrow F, the clutch operating valve 55 is switched to the position a (see FIG. 1), and the one-way clutch 18 is activated. The movement of the piston rod 10 in the direction of arrow B is prevented. As a result, the piston 14 moves in the direction of arrow F, and its stepped portion 14a fits into the third pressure chamber 23, causing the inside of the second pressure chamber 22 to move. Even if the piston 14 receives a strong reaction force in the direction of the arrow B due to the pressure, the movement of the piston 14 in the direction of the arrow B is prevented by the action of the position direction cushion 18. Therefore, even if the throttle 32 for releasing the air in the second pressure chamber 22 to the outside is narrowed, the piston rod 10 does not bounce back and moves extremely smoothly only in the direction of arrow F (forward movement). ) will be done. When the load attached to the piston rod 10 is large or the moving speed of the piston 14 is extremely high, the throttle 32 can be sufficiently narrowed to fully utilize the buffering function of the cushion mechanism 1.

Further, since the movement of the piston rod 10 in the direction of arrow B is completely prevented by the one-way clutch 18, the configuration of the cushion mechanism 1 is not limited to a configuration that restricts the exhaust gas, and for example, as shown in FIG. As shown in FIG. 2, a configuration using a simple spring 60 may also be used. Conventionally, springs could not be used as shock absorbers because they bounced back, but the configuration of the present invention allows for a simple configuration.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment in any way. For example, as shown in FIG.
The present invention may include a structure in which the structure of the clutch operating valve 62 is simplified by using a clutch valve 62, or a structure in which a one-way clutch is provided inside the first cylinder 3 so that the same effect can be obtained not only when moving forward but also when reversing. It goes without saying that the invention can be implemented in various ways without departing from the spirit of the invention.

Effects of the Invention As detailed above, according to the shock absorbing device of the present invention, since the movement of the piston rod can be prevented by the one-way clutch, it has the excellent effect of making the shock absorbing operation reliable and smooth. especially,
This effect becomes significant when a strong biasing force in the counter-movement direction is required due to the magnitude of the load attached to the piston rod or the magnitude of the movement speed of the piston rod.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view illustrating a pneumatic cylinder with a shock absorber according to an embodiment of the present invention when the cylinder is moving forward, FIG. FIG. 3 is a cross-sectional view showing an example configuration. DESCRIPTION OF SYMBOLS 1... Cushion mechanism part, 3, 5... First and second cylinders, 7... Head cover, 9... Rod cover, 10... Piston rod, 12... First cylinder chamber, 14... Piston, 16... …Second
Piston chamber, 20... One-way clutch portion, 21...
...First pressure chamber, 22...Second pressure chamber, 23...Third pressure chamber, 30...Pressure adjustment section, 41...Storage section, 43...Clutch body, 45...Steel ball, 47
...retainer.

Claims (1)

[Claims for Utility Model Registration] Provided in a cylinder device that drives a piston based on the pressure balance between chambers on both sides of the piston, when the piston moves in at least one direction, it applies a biasing force against the movement just before the end of the movement. In a shock absorber equipped with a cushion mechanism, a clutch body having an internal tapered surface expanding in the direction of movement of the piston rod is fitted onto the piston rod, and a steel ball is held within the clutch body in contact with the piston rod. A shock absorber comprising: a directional clutch; and a clutch-free mechanism that releases the one-way clutch by releasing the contact between the steel balls and the clutch body.