JPH0743505Y2 - Air damper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an air damper in which a pair of pistons are inserted so as to face each other from both open ends of a cylinder.

[Prior Art] Conventionally, an air damper of this type includes a cylinder whose both ends are open, and a pair of pistons which are slidably inserted into the cylinder so as to face each other from both open ends of the cylinder. is there.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional air damper, when both pistons are pushed in the directions in which they approach each other in the cylinder, they shorten.
On the contrary, it can be extended by pulling it in the direction of separating, and only two states of the minimum shortened state and the maximum extended state can be acquired. If you try to pull out the piston further from the maximum extended state, the piston will come out of the cylinder and be damaged. was there.

For example, when used as a shock absorber for a lid opening / closing device,
The minimum shortened state is set to the closed position of the lid, the maximum extended state is set to the opened position of the lid, the lid is always biased in the opening direction by a spring or the like, and the braking force is exerted by the extension process of the damper. In such a lid opening / closing device, the damper will not be damaged as long as it is generally used, but if it reaches the end user's hand, it may be used unexpectedly. For example, the lid may be open, but you may be forced to open it further. Then, since the damper is in the maximum extension state, the piston may come out of the cylinder.

Therefore, the present invention has been made in view of the above problems of the above-described conventional technique, and its purpose is to allow the piston to be withdrawn in two stages and to prevent damage to the damper. It is something to prevent.

[Means for Solving the Problems] Therefore, the present invention is to achieve the above object, and the contents thereof will be described below with reference to the embodiments shown in the drawings.

The present invention relates to an urging means (for example, a coil spring) for urging one piston (for example, the first piston 3) in the extension direction and the other piston (for example, the second piston 4) in the cylinder (2) in the contraction direction. A unidirectional exhaust groove which is provided in the one piston (3) and is opened in the shortening step against the biasing force of the biasing means and closed in the extension step by the biasing force of the biasing means. (8) is formed, and the other piston (4) is unidirectionally opened in the extension step against the biasing force of the biasing means and closed in the shortening step by the biasing force of the biasing means. An exhaust groove (12) is formed.

[Operation] Therefore, according to the present invention, when both pistons (3, 4) are pushed toward each other in the cylinder (2), one piston (3) that has been urged in the extension direction is It is shortened against the urging force of the urging means (13) (Fig. 6). In this shortening step, the exhaust groove (8) of one piston is opened, so the air in the cylinder is exhausted at once through this open exhaust groove, and the damper effect does not occur. The other piston (4) has already been shortened by the urging force of the urging means, so it will not be further shortened.

Next, when the force pushing both pistons is released, the one piston (3) is pushed back by the biasing force accumulated in the biasing means. In this extension step, since the exhaust groove of one piston is closed, negative pressure is generated in the cylinder, and the outside air is sucked into the cylinder through the orifice (9) opened at a predetermined position. Therefore, the damper effect occurs,
One of the pistons slowly and quietly expands and returns to its original state by the damped biasing force of the biasing means (Figs. 1, 2, 4).

On the other hand, when both pistons are pulled in a direction away from each other, the other piston (4), which has been urged in the shortening direction, extends (FIG. 7). In this extension step, the exhaust groove (12) of the other piston is opened, so the outside air is sucked into the cylinder at once through the opened exhaust groove, and the damper effect does not occur.

Next, when the pulling force of both pistons is released, the other piston is pulled back by the biasing force accumulated in the biasing means. In this shortening step, the exhaust groove of the other piston is closed, so the internal pressure in the cylinder rises and the air in the cylinder is exhausted from the orifice. Therefore, a damper effect is generated, and the other piston is slowly and quietly shortened by the urging force attenuated by the urging means to return to the original state.

[Embodiment] The present invention will be described below based on an embodiment shown in the drawings.

In the figure, reference numeral 1 denotes an air damper. The damper 1 includes a cylinder 2 having both ends open, and a pair of first first and second slidably inserted into the cylinder 2 from opposite open ends of the cylinder 2. It consists of the second piston 3 and 4.

The cylinder 2 has a first inner chamber in which the first piston 3 slides.
2a, a second inner chamber 2a on which the second piston 4 slides, and a relatively small-diameter communication passage that connects the first inner chamber 2a and the second inner chamber 2b to each other.
It has 2c, and is integrally molded with a resin such as POM having appropriate rigidity and elasticity.

Further, in the figure, reference numeral 5 denotes a cap that closes the open end of the first inner chamber 2a of the cylinder 2, and this cap 5 has an oval through hole 5a through which the rod portion 3c of the first piston 3 passes. POM
It is integrally molded with resin such as. Then, between the cylinder 2 and the cap 5, one of the concavo-convex portions 2'and 5'fitting with each other is formed respectively, and the cap 5 is formed by utilizing the elasticity of at least one of the concavo-convex portions 2'and 5 '. The cylinder 2 can be fixed to the outer circumference of the opening end with one touch.

The first piston 3 has an annular piston portion 3a having an outer diameter substantially equal to the inner diameter of the first inner chamber 2a of the cylinder 2 and one end opened at the end face of the piston portion 3a and extending partway in the axial direction. And the other end is closed, and the rod portion 3c has a hollow chamber 3b having an oval-shaped cross section, and is integrally molded of resin such as POM.

An annular ring groove 7 for mounting the O-ring 6 is formed on the outer circumference of the piston portion 3a. The groove width of the ring groove 7 is wider than the cross-sectional diameter of the O-ring 6 (for example, about twice).
, And a pair of exhaust grooves 8, 8 recessed one step lower at the bottom and located at the rear end in the axial direction are formed in a back-facing direction. or,
An orifice 9 is formed at the closed end of the hollow chamber 3b so as to open outward in the axial direction.

The second piston 4 has an outer diameter substantially equal to the inner diameter of the second inner chamber 2b of the cylinder 2, and has a relatively large piston portion 4a.
And extends from the front surface of the piston portion 4a in the axially forward direction, and extends from the communication passage 2c of the cylinder 2 through the first inner chamber 2a to the first inner chamber 2a.
It is composed of a tip shaft portion 4b fitted into the hollow chamber 3b of the piston 3, and a rod portion 4c extending axially rearward from the rear surface of the piston portion 4a and protruding outward from the second inner chamber 2b of the cylinder 2.
For example, it is integrally molded with resin such as POM.

An annular groove 11 for mounting an O-ring 10 is formed on the outer circumference of the piston portion 4a, and the bottom of the ring groove 11 has a structure similar to that of the exhaust groove 8 described above and has an axial tip end. A pair of exhaust grooves 12 and 12 are formed so as to face each other.

The tip shaft portion 4b has a flat plate shape and is fitted with a coil spring 13 as an urging means. The tip portion of the tip shaft portion 4b has a relatively large size that fits into the hollow chamber 3b of the first piston 3. A stopper 14 having a large diameter is attached to prevent the coil spring 13 from coming off. The stopper 14 is integrally formed of resin such as POM, and one of the concavo-convex portions 14 'and 4'fitting with each other is formed between the distal end shaft portion 4b and the outer periphery of the distal end shaft portion 4b. ,
By utilizing the elasticity of at least one of 4 ', the stopper 14 can be fixed to the outer circumference of the tip end portion of the tip end shaft portion 4b with one touch.

The outer diameter of the coil spring 13 is smaller than the inner diameter of the communication passage 2c of the cylinder 2, and the coil spring 13 is elastically compressed between the front surface of the annular convex portion 15 protruding inward into the communication passage 2c and the rear surface of the stopper 14. . Further, the coil spring 13 has a winding diameter larger than the minimum facing distance of the hollow chamber 3b of the first piston 3, and when the stopper 14 advances in the hollow chamber 3b of the first piston 3, the front surface of the piston portion 3a thereof. And the front surface of the annular convex portion 15 of the cylinder 2 are elastically contracted.

The rod portion 4c of the second piston 4 has a flat plate shape and extends from the rear surface of the piston portion 4a to the middle of the length thereof and has a pair of reinforcing blades 4c ', 4c' orthogonal to each other in a cross shape.

Next, the damper 1 in the assembled state having the above-mentioned configurations
The action of will be explained.

First, both pistons of the damper 1 in the state shown in FIG.
Pushing 3 and 4 toward each other, the first piston 3
While the piston portion 3a of the second piston 4 advances relatively in the first inner chamber 2a of the cylinder 2, and the tip shaft portion 4b of the second piston 4 stops.
Together with 14, the hollow body 3b of the first piston 3 is relatively advanced.

At that time, the end surface of the coil spring 13 fitted on the tip end shaft portion 4b of the second piston 4 is the piston portion of the first piston 3.
Since it abuts against the front surface of 3a, the coil spring 13 is elastically contracted with the front surface of the annular convex portion 15 of the cylinder 2. Therefore, when pushing both pistons 3 and 4, the coil spring 1
It is necessary to push in against the spring force of 3.

When the piston portion 3a of the first piston 3 advances in the first inner chamber 2a of the cylinder 2, the ring groove 7 of the piston portion 3a
The O-ring 6 fitted on the inner side of the first inner chamber 2a of the cylinder 2 is relatively retracted in the ring groove 7 due to frictional resistance with the inner circumference of the first inner chamber 2a, and is positioned above the exhaust groove 8 at the bottom of the ring groove 7. To do. Therefore, the air in the first inner chamber 2a of the cylinder 2 is exhausted all at once through the exhaust groove 8 and the orifice 9 opening at the closed end of the hollow chamber 3b of the first piston 3, and the damper effect does not occur.

In this way, when both pistons 3 and 4 are pushed in, the first piston 3
The front surface of the piston portion 3a hits the step surface 16 between the first inner chamber 2a of the cylinder 2 and the communication passage 2c which is narrower than the first inner chamber 2a, so that the piston portion 3a cannot be further pushed (Fig. 6).

When the pushing force is released here, the piston portion 3a of the first piston 3 is relatively pushed back in the first inner chamber 2a of the cylinder 2 by the restoring force of the coil spring 13 which has been elastically contracted.

Therefore, the piston portion 3a of the first piston 3 is
Of the first piston 3 together with the stopper 14 so that the tip end shaft portion 4b of the second piston 4 moves backward in the first inner chamber 2a.
Relatively retracts in the hollow chamber 3b.

At that time, the ring groove 7 of the piston portion 3a of the first piston 3
The O-ring 6 externally fitted to the cylinder 2 relatively advances in the ring groove 7 due to frictional resistance with the inner circumference of the first inner chamber 2a of the cylinder 2, thereby closing the exhaust groove 8. Therefore, since the first inner chamber 2a of the cylinder 2 is sealed, the piston portion 3a retracts, so that the first inner chamber 2a is negatively pressured. Therefore, the first piston 3
Through the orifice 9 opening at the closed end of the hollow chamber 3b of
The outside air is taken into the first inner chamber 2a of the cylinder 2.

At this time, since the O-ring 10 fitted on the ring groove 11 of the piston portion 4a of the second piston 4 is in the retracted position in the ring groove 11 and closes the exhaust groove 12, Air does not flow into the first inner chamber 2a from the second inner chamber 2b through the communication passage 2c.

Therefore, in this extension step, a damper effect occurs, and the pistons 3 and 4 extend slowly and quietly due to the restored restoring force of the coil spring 13.

Then, the rear surface of the piston portion 3a of the first piston 3 stops at the position where it abuts against the inner surface of the cap 5 (first
Figure).

On the other hand, when the two pistons 3 and 4 are pulled in the direction in which they are separated from each other, the piston portion 4a of the second piston 4 moves into the second portion of the cylinder 2.
Retreat relatively in the inner chamber 2b.

At that time, the tip end shaft portion 4b of the second piston 4 relatively retracts together with the stopper 14 in the first inner chamber 2a of the cylinder 2, so that the rear surface of the stopper 14 and the front surface of the annular convex portion 15 of the cylinder 2 are separated from each other. The coil spring 13 is contracted between. Therefore, when pulling both pistons 3 and 4, it is necessary to pull them against the spring force of the coil spring 13.

When the piston portion 4a of the second piston 4 retracts from the second inner chamber 2b of the cylinder 2, the ring groove 11 of the piston portion 4a
The O-ring 10 that is fitted to the inner side of the second inner chamber 2b of the cylinder 2 is relatively advanced in the ring groove 11 due to the frictional resistance with the inner circumference of the second inner chamber 2b, and is positioned above the exhaust groove 12 at the bottom of the ring groove 11. To do. Therefore, the outside air is sucked into the second inner chamber 2b of the cylinder 2 at once through the exhaust groove 12, so that the damper effect is not generated.

At this time, since the O-ring 6 fitted on the ring groove 7 of the piston portion 3a of the first piston 3 is in the forward position in the ring groove 7 and closes the exhaust groove 8, the exhaust groove 8 is closed. No outside air is taken in through 8. However, since the orifice 9 of the hollow chamber 3b of the first piston 3 is open, some outside air flows in through the orifice 9.

In this way, when both pistons 3 and 4 are pulled, the rear surface of the stopper 14 comes into contact with the step surface 16 of the cylinder 2 so that it cannot be pulled any further (Fig. 7).

When the pulling force is released here, the piston portion 4a of the second piston 4 is relatively pulled back in the second inner chamber 2b of the cylinder 2 due to the restoring force of the coil spring 13 that has been elastically contracted.

Therefore, the piston portion 4a of the second piston 4 becomes the cylinder 2
Of the second inner chamber 2b, the tip shaft portion 4b of the second inner chamber 2b moves forward together with the stopper 14 in the hollow chamber 3b of the first piston 3.

At that time, the ring groove 11 of the piston portion 4a of the second piston 4
The O-ring 10 which is fitted to the inside of the cylinder 2 relatively retracts inside the ring groove 11 due to the frictional resistance with the inner circumference of the second inner chamber 2b of the cylinder 2, thereby closing the exhaust groove 12. Therefore, the second inner chamber 2b of the cylinder 2 is sealed, and the piston portion 4a moves forward, so that the first inner chamber 2a, the communication passage 2c, and the second inner chamber of the cylinder 2 are advanced.
2b and the air in the hollow chamber 3b of the first piston 3 are compressed. Therefore, the air in the cylinder 2 and the hollow chamber 3b of the first piston 3 is exhausted while being narrowed down through the orifice 9.

Therefore, in this shortening step, a damper effect occurs, and the pistons 3 and 4 are slowly and quietly shortened by the restored restoring force of the coil spring 13.

Then, the front surface of the piston portion 4a of the second piston 4 stops at a position where it comes into contact with the step surface 17 between the second inner chamber 2b of the cylinder 2 and the communication passage 2c which is narrower than that (see FIG. 1). ).

Next, the usage example of the damper 1 will be described. For example, as shown in FIG. 8, it can be used for a lid opening / closing device.

The lid 18 is axially fixed to the open upper surface of the case 19 so as to open upward. Then, one of the rod portions 3c, 4c of both pistons 3, 4 is axially locked between the lid 18 and the case 19, respectively, and the lid 1 is opened upward, and the damper 1 is shown in FIGS. Make it the state shown.

Therefore, according to this embodiment, when the lid 18 is closed downward about the shaft 20 as the fulcrum, the damper 1 is shortened and the coil spring is closed.
The restoring force is accumulated in 13 (Fig. 6). If the locking means (not shown) is operated in this closed position, the lock is released, and the lid 18 becomes a coil spring.
Due to the restoring force of 13 and the damper effect, it opens slowly and quietly upward.

In addition, even if the lid 18 is inadvertently opened upward from the open state, the damper 1 is further extended (FIG. 7) to cope with it, and after the force is released, the restoring force of the coil spring 13 is reduced. Due to the damper effect, the lid 18 returns to its original open position slowly and quietly.

The lid 18 can be used in the same manner not only when it is opened by rotating it but also when it is opened by sliding it. Further, the damper 1 can be used in various fields, for example, as an opening / closing door for a TV stand, a microwave oven, etc., and an opening / closing device for various lids such as a glow box and a center console box in a vehicle compartment. be able to.

[Effect of the Invention] As described above, according to the present invention, even if a force is applied to both pistons in the cylinder so as to approach each other or in the direction away from each other, the urging force of the urging means causes It is possible to provide an air damper that slowly returns to its original state with a damper effect.

[Brief description of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a sectional view, Fig. 2 is a plan view, Fig. 3 is a side view, and Fig. 4 is the same as above.
Sectional view taken along line IV-IV, FIG. 5 is a sectional view taken along line VV of FIG. 2, FIG. 6 is a sectional view showing a shortened state corresponding to FIG. 1, and FIG. 7 corresponds to FIG. Sectional view showing a stretched state,
FIG. 8 is a sectional view showing a usage example. 1 ... Air damper, 2 ... Cylinder, 3 ... First piston,
4 ... 2nd piston, 8 ... Exhaust groove, 9 ... Oris, 12 ... Exhaust groove, 13 ... Coil spring as an urging means.

Claims (1)

[Scope of utility model registration request] 1. An air damper comprising a cylinder having open both ends, and a pair of pistons slidably inserted into the cylinder so as to face each other from both open end portions of the cylinder. A biasing means for biasing the piston in the extension direction and the other piston in the shortening direction is provided, and the one piston is opened in the shortening step against the biasing force of the biasing means, and A unidirectional exhaust groove is formed which is closed in the extension step by the urging force, and the other piston is opened in the extension step against the urging force of the urging means and shortened by the urging force of the urging means. An air damper characterized in that a unidirectional exhaust groove that is closed in the process is formed.