JPH1113812A - Gas spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform accurately and smoothly lock and cancel of lock for a piston rod, by engaging a stopper, which is arranged on the periphery of a piston rod, into the groove of a bearing during fastening a cap, and by energizing a cap in the loosening direction on the upper wall side of the cap. SOLUTION: When a stopper 3 is used in the switching structure of a back door of an automobile, usually, friction between a cylindrical part 3b of the stopper 3 and the periphery of a piston rod 1 is small. When the back door is pulled up in the opening direction, the back door is easily opened because a piston rod 1 is energized in the stretching direction with gas pressure. In this case, when a cap 2 is turned and declined to stop the back door in arbitrary opening angle, the stopper 3 declines and its cylindrical part 3b deeply enters into a groove 10 of a bearing 5. Therefore, friction between the cylindrical part 3b and the piston rod 1 increases, and the piston rod 1 is locked by this friction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas spring used for opening and closing a back door of an automobile, opening and closing a window of a building, and the like.

[0002]

2. Description of the Related Art Generally, a back door of an automobile is opened / closed via a gas spring interposed between the back door and the vehicle body to release the lock of the back door and manually push up the back door slightly. The gas pressure causes the gas spring to slowly expand, which also causes the back door to slowly open upward. Further, when the back door is opened to the extent necessary for the luggage to enter and exit the trunk, it can be locked and stopped at this position.

[0003] As such a gas spring, for example, a gas spring disclosed in Japanese Utility Model Laid-Open No. 49-128957 has been developed.

[0004] As shown in FIG.
A hollow lock nut 32 is screwed into a bearing 33 provided at an end of a cylinder 34 so as to be vertically movable, and an elastic wedge-shaped stopper 31 is fitted into an upper conical hollow portion 36 of the lock nut 32. The inner periphery of the stopper 31 is brought into sliding contact with the outer periphery of the piston rod 35. This conventional gas spring uses a lock nut 32 to open the back door and lock and stop at an arbitrary position.
The stopper 31 is thereby rotated downward to tighten the stopper 31 radially inward on the tapered surface of the hollow portion 36, in other words, by tightening the stopper 31 in the direction of the piston rod 35.
The friction between the piston rod 35 and the piston rod 35 is increased, and the extension operation of the piston rod 35 is stopped.

[0005]

The above-mentioned conventional gas spring has no particular problem in function, but may have the following problems.

That is, when the lock nut 32 is tightened and lowered, friction occurs between the lock nut 32 and the stopper 31 and friction also occurs between the stopper 31 and the piston rod 35 as described above. If the friction between the lock nut 32 and the stopper 31 is greater than the friction between the stopper and the piston rod, it may be difficult to loosen the lock nut 32 and release the lock.

Further, when the lock nut 32 is formed of a synthetic resin, there is a problem that the durability is poor and the strength is low.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas spring which can be locked and unlocked reliably and smoothly, is durable and has high strength.

[0009]

According to one aspect of the present invention, a bearing is provided at an end of a cylinder, and a piston rod is moved in the cylinder via the bearing and the piston. A gas spring, which is freely inserted and the piston rod is constantly urged in the direction of extension by the gas pressure in the cylinder, forms a conical groove at the outer end of the bearing and fixes the collar to the outer periphery of the end of the cylinder. A cap having a U-shaped cross section is vertically coupled to the outer periphery of the collar, and a stopper urged toward the upper wall is disposed between the collar and the upper wall of the cap so as to be vertically movable. It is characterized by comprising a flange abutting on the upper wall of the cap and a cylindrical portion slidingly contacting the outer periphery of the piston rod and fitting into the groove of the bearing.

In this case, it is preferable that a spring is interposed between the flange and the collar, and a tapered surface which slides on the tapered inner periphery of the groove is formed on the outer periphery of the cylindrical portion.

In another aspect of the present invention, a bearing is provided at an end of a cylinder, and a piston rod is movably inserted into the cylinder via the bearing and a piston. A groove is formed in the outer end of the bearing of a gas spring that is constantly urged in the direction of extension by gas pressure, and a collar is fixed to the outer periphery of the end of the cylinder. An elastic ring which is movably connected and which faces the upper wall of the cap and slides on the outer periphery of the piston rod is fitted in the groove.

In the above two means, it is preferable that the cap and the collar are formed of a metallic material.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a main part of a gas spring A according to an embodiment of the present invention. As is well known, a gas spring A has a bearing 5 provided at an end of a cylinder 9 and a piston rod 1 is movably inserted into the cylinder 9 via the bearing 5 and a piston. The gas is always urged in the direction of extension by the gas pressure in 9. In this gas spring A, a conical groove 10 is formed at the outer end of the bearing 5, and a collar 7 made of a metallic material is fixed to the outer periphery of the end of the cylinder 9 by welding or the like. A cap 2 having a U-shaped cross section and made of a metallic material is vertically coupled via a screw 11 and a stopper 3 urged between the collar 7 and the upper wall 2a of the cap 2 toward the upper wall 2a. The stopper 3 is composed of a flange 3a contacting the upper wall 2a of the cap 2 and a cylindrical portion 3b slidingly contacting the outer periphery of the piston rod 1 and fitting into the groove 10 of the bearing 5. I have.

In the cylinder 9, two chambers defined by pistons are defined, and the piston rod 1 is urged in the direction of extension by the gas pressure of the gas sealed in these chambers, and the outer end of the piston rod 1 is The end of the cylinder 9 is connected to, for example, a back door and a vehicle body of an automobile via a bracket.

A seal 6 and a retainer 8 are arranged above the cylinder.

The bearing 5 is fixed to the end of the cylinder 9 by caulking or the like, and a groove 10 formed on the upper surface, which is the outer end of the bearing 5, is formed in a conical shape with a tapered surface that expands outward.

The cap 2 has a cylindrical portion 2b, an upper wall 2a and a hole 2
c, and is formed in a U-shaped cross section, that is, a bottomed cylindrical shape.

A coil spring 4 is interposed between the upper end of the collar 7 and the flange 3a constituting the stopper 3, and the stopper 3 is constantly pressed against the upper wall of the cap 2.
Another known elastic body may be used instead of the coil spring 4.

The cylindrical portion 3b of the stopper 3 is vertically movably fitted into the groove 10 of the bearing 5. A tapered surface is formed on the outer periphery of the cylindrical portion 3b. It is preferred that it abuts movably.

Next, the operation will be described.

Normally, the friction between the cylindrical portion 3b of the stopper 3 and the outer periphery of the piston rod 1 is small, so that the lock between the back door and the vehicle body is released, and the back door is manually pulled up slightly in the opening direction. Since the piston rod 1 of the gas spring A is urged in the extending direction by the gas pressure, this lifting force is assisted, and the back door can be opened slowly and lightly. At this time, if it is desired to stop the back door at an arbitrary opening angle, the cap 2 is turned down. At this time, coil spring 4
The stopper 3 descends against this, and its cylindrical portion 3b penetrates deeply into the groove 10 of the bearing 5. Groove 10 of bearing 5
Since the lower portion is narrow and conical, the cylindrical portion 3 b of the stopper 3 is forcibly compressed and pressed against the outer periphery of the piston rod 1. Therefore, the friction between the cylindrical portion 3b and the piston rod 1 increases, and the piston rod 1 is locked and stopped by the friction, so that the back door also stops. When the back door is widely opened from this position to an arbitrary angle, or when the back door is closed, the cap 2 is rotated to move upward in a manner opposite to the above. In this case, the pressing force of the cap 2 against the stopper 3 is released, the stopper 3 is pushed upward by the restoring force of the spring 4, and the cylindrical portion 3b moves above the groove 10, so that the piston rod 1 of the stopper 3 And the friction is also reduced, so that the piston rod 1 can move again. When the back door is greatly opened, the back door may be pulled up with the extension of the piston rod 1, and when the back door is closed, the back door may be pushed in the closing direction against the gas pressure.

FIG. 2 shows a main part of a gas spring A according to another embodiment of the present invention.

1, a bearing 5 is provided at the end of a cylinder 9 and the piston rod 1 is movably inserted into the cylinder 9 via the bearing 5 and a piston. The piston rod 1 is constantly urged in the extending direction by the gas pressure in the cylinder 9. Further, in the gas spring A, a groove 12 is formed at the outer end of the bearing 5, a collar 7 is fixed to the outer periphery of the end of the cylinder 9, and the cap 2 having a U-shaped cross section is vertically movable around the outer periphery of the collar 7. An elastic ring 13 as a stopper is fitted in the groove 12 so as to face the upper wall 2a of the cap 2 and slide on the outer periphery of the piston rod 1.

The ring 13 is formed of an O-ring made of rubber or the like, and may be loosely fitted in the groove 12 or may be held between the upper wall 2a of the cap 2 and the bottom surface of the groove 12. . In addition, the inner peripheral surface of the ring 13 may lightly abut the outer periphery of the piston rod 1, or an arbitrary gap may be provided.

The other structure is the same as that of the gas spring A shown in FIG.

In the gas spring A shown in FIG. 2, when the back door is unlocked as in FIG.
Can be moved in the direction of elongation by gas pressure.

When it is desired to stop the back door at an arbitrary position, when the cap 2 is rotated and lowered, the ring 13 is pressed by the upper wall 2a of the cap 2, and the upper wall 2a and the groove 1 are pressed.
The ring 13 is flattened by being crushed by the bottom surface of the ring 2 and extends in the inner circumferential direction and the outer circumferential direction. Because of this ring 1
3 is pressed against the outer periphery of the piston rod 1 and the ring 1
Friction between the piston rod 3 and the piston rod 1 increases,
The back door stops because the movement of the piston rod 1 is locked by this friction. To open the back door further from this state again or to close the back door, the cap 2 is loosened and the ring 13
Is returned to the original state, the friction of the ring 13 with the piston rod 1 can be eliminated or reduced, so that the piston rod 1 can expand and contract,
The back door can be moved in an opening direction or a closing direction.

Other functions and effects are the same as those in FIG.

[0030]

According to the present invention, the following effects can be obtained.

According to the first and second aspects of the present invention, the stopper disposed on the outer periphery of the piston rod fits into the groove of the bearing when the cap is tightened, so that friction with the piston rod is increased and the lock of the piston rod is increased. Smooth and reliable. Also, since the cap is urged in the pull-out direction, which is the upper wall side of the cap, when the cap is loosened, the stopper loosens automatically and the friction on the piston rod can be reduced, and the lock on the piston rod is released smoothly and reliably. Can be done.

According to the third aspect of the present invention, since the elastic ring disposed on the outer periphery of the piston rod functions as a stopper, when the cap is tightened, this ring is deformed to increase friction with the piston rod,
The piston rod can be locked smoothly and reliably. Also, when the cap is loosened, the ring automatically returns to its original state with the self-returning force, and the friction on the piston rod can be reduced or eliminated, so the unlocking of the piston rod can be released smoothly and reliably. I can do it.

According to the fourth aspect of the present invention, since the cap and the collar or the metal material are used, the durability and the strength can be increased.

[Brief description of the drawings]

FIG. 1 is a partially cut-away vertical front view of a gas spring according to an embodiment of the present invention.

FIG. 2 is a partially cutaway longitudinal front view of a gas spring according to another embodiment of the present invention.

FIG. 3 is a partially cut-away vertical front view of a conventional gas spring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piston rod 2 Cap 2a Upper wall 3 Stopper 3a Flange 3b Cylindrical part 4 Spring 5 Bearing 7 Collar 9 Cylinder 10 Conical 12 Groove 13 Elastic ring A Gas spring

Claims (4)

[Claims] 1. A bearing is provided at an end of a cylinder, and a piston rod is movably inserted into the cylinder via the bearing and a piston, and the piston rod is constantly urged in an extending direction by gas pressure in the cylinder. In the gas spring, a conical groove is formed at the outer end of the bearing, a collar is fixed to the outer periphery of the end of the cylinder, and a cap having a U-shaped cross section is coupled to the outer periphery of the collar to move up and down. A stopper urged to the upper wall side is disposed between the collar and the upper wall of the cap so as to be movable up and down, and the stopper slides on a flange abutting on the upper wall of the cap and an outer periphery of the piston rod and has a groove in the bearing. A gas spring, comprising: a cylindrical portion fitted into the gas spring. 2. The gas spring according to claim 1, wherein a spring is interposed between the flange and the collar, and a tapered surface is formed on an outer periphery of the cylindrical portion so as to be in sliding contact with a tapered inner periphery of the groove. 3. A bearing is provided at an end of the cylinder, and a piston rod is movably inserted into the cylinder via the bearing and the piston, and the piston rod is constantly urged in a direction of extension by gas pressure in the cylinder. In the gas spring that has been made, a groove is formed at the outer end of the bearing,
A collar is fixed to the outer periphery of the end of the cylinder, and a cap having a U-shaped cross section is coupled to the outer periphery of the collar so as to be movable up and down. A gas spring characterized by fitting a simple ring. 4. The gas spring according to claim 1, wherein the cap and the collar are formed of a metallic material.