JPH045786Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a means for ensuring safety when a stay damper that assists in opening and closing a swing door receives an abnormal load such as an impact.

(Prior art) As a stay damper that is interposed between the surrounding frame and the swing door to assist in opening and closing, a piston is housed in a cylinder filled with gas so that it can slide freely. A piston rod in which the piston rod protrudes freely to the outside is well known. When this kind of stay damper contracts, the gas enclosed in it is compressed and the repulsive force is strengthened. Therefore, when the stay damper is fully contracted due to abnormal compressive force such as an impact, the bracket holding the piston rod may not be able to withstand the load. If the piston rod breaks without being overcompressed, the piston rod, suddenly released from overcompression, may be ejected from the cylinder by the gas pressure.

Therefore, in order to prevent this phenomenon, a part of the sealed cylinder is damaged in response to abnormal compression force, and the gas inside the cylinder is released into the atmosphere to prevent the piston rod from protruding. A stay damper with such safety measures has been proposed (Japanese Patent Application Laid-Open No. 61-291216). This is designed to prevent the piston rod from flying forward even if the bracket is damaged due to an impact such as a rear-end collision of a stay damper installed in a swing door at the rear of an automobile.

(Problem that the invention aims to solve) However, in the case of this stay damper, the cylinder is damaged when the load exceeds a certain value, so slight errors in processing and assembling the parts can cause the difference between the design load and the actual load at failure. There was a problem that there was a considerable difference between the two, making it difficult to ensure reliable operation.

SUMMARY OF THE INVENTION In view of these problems, an object of the present invention is to provide a stay damper that can more reliably release the filled gas during abnormal contraction.

(Means for Solving the Problem) The present invention includes a piston that is slidably housed inside a cylinder filled with gas, a piston rod coupled to the piston that is slidably protruded from the cylinder, and the protruding end A stay damper for a swing door that supports the piston rod so that it can slide freely in a swing door stay damper that supports the opening and closing of the swing door by locking the piston rod and the base end of the cylinder through brackets, one to the swing door and the other to the surrounding frame. At the same time, a bush which is displaced in the axial direction toward the inside of the cylinder due to collision with the bracket at the tip of the piston rod is held at the tip of the cylinder, and a gas passage is formed by passing through this bush vertically, and a gas passage is formed by passing through this bush. A sealing member that is deformed and separated from the piston rod is interposed adjacent to the bush and between the cylinder and the piston rod.

(Operation) When the piston rod penetrates deep into the cylinder due to an abnormal load such as an impact, the bracket of the piston rod collides with the bush held at the tip of the cylinder, displacing the bush in the axial direction. This displacement deforms the adjacent seal member,
The gas sealed in the cylinder is discharged into the atmosphere from between the deformed seal member and the piston rod via a gas passage that runs vertically through the bush.

(Example) An embodiment of the present invention is shown in FIGS. 1 and 2.

In FIG. 1, reference numeral 1 denotes a cylinder filled with gas, and a piston 2 is slidably housed inside the cylinder 1. A piston rod 3 is connected to the piston 2 and protrudes from the tip of the cylinder 1 so as to slide freely. The end of the piston rod 3 is locked to either the swing door or the surrounding frame via a ball-shaped bracket 4, and the base end of the cylinder 1 is locked to the other via a similar bracket 5. . A passage 6 is vertically provided in the piston 2 to allow gas to flow on both sides during sliding.
A bush 8 press-fitted into the inside of a bearing 7 at the tip of the cylinder 1 and a seal 9 made of an elastic material provided adjacent to the bush 8 are in sliding contact with the piston rod 3, allowing it to move freely in the axial direction and in an oil-tight manner. supported by. There is a bush 8 inside the bearing 7.
A stepped portion 7A is formed to prevent the piston rod from coming off, and the tip side of the stepped portion 7A opens with a certain clearance between it and the piston rod 3. Note that this opening 7B is formed to have a larger diameter than the base end 4A of the bracket 4. As shown in FIG. 2, a groove-shaped gas passage 8A is vertically provided in the bush 8 in the axial direction facing the outer periphery of the piston rod 3. The seal 9 is held inside the cylinder 1 in contact with the bush 8, and its lip-shaped inner circumferential portion slides against the piston rod 3.
10 is an elastic material that prevents the piston 2 from being extended;
Reference numeral 11 denotes a holder for locking the elastic material 10 and the outer circumference of the seal 9 to the cylinder 1. Note that the length of the piston rod 3 is the same as that of the base end 4 of the bracket 4.
A and the bush 8 are set to collide between the normal maximum pressure stroke position of the piston 2 and the time when the piston 2 bottoms out.

Next, the action will be explained.

Under normal conditions, the piston 2 does not enter the cylinder 1 beyond the maximum pressure stroke position, and the bracket 4
The base end 4A of the bush 8 never comes into contact with the bush 8.

However, when a strong compressive force is applied to the stay damper due to an abnormal impact and the piston 2 moves beyond the maximum pressure stroke position and enters the cylinder 1, the base end 4A of the bracket 4 is inserted into the opening 7B of the bearing 7.
It enters into the cylinder 1 and collides with the bush 8. The bush 8, which is simply press-fitted into the bearing 7, is displaced toward the bottom of the cylinder 1, and deforms the adjacent seal 9 by pushing it apart from the inside. As a result, a gap is created between the seal 9 and the piston rod 3, and the gas sealed in the cylinder 1 flows out through this gap through the gas passage 8A vertically provided in the bush 8. As a result, the repulsive force of the stator damper is instantly lost, and even if the brackets 4 and 5 are damaged due to impact, there is no risk that the piston rod 3 will fly out from the overcompressed cylinder 1.

(Effects of the invention) As described above, the invention press-fits a bushing into the inlet of the cylinder, and when the piston enters the cylinder beyond the normal maximum pressure position, the bracket collides with this bushing and the seal behind the bushing is damaged. In order to deform the cylinder, the gas filled in the cylinder is released into the atmosphere through a gas passage installed vertically in the bush. Therefore, the stay damper instantly loses its repulsive force, and even if the bracket is damaged, the piston rod will not fly out from the overcompressed cylinder.

Further, since the present invention has a simple structure consisting of a bush, a bracket, and a seal, it can be easily implemented at a small cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a stay damper showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a bush in the same example. 1... Cylinder, 2... Piston, 3... Piston rod, 4... Bracket, 8... Bush, 8A... Gas passage, 9... Seal.

Claims (1)

[Scope of utility model registration request] A piston is slidably housed inside a cylinder filled with gas, a piston rod connected to the piston is slidably protruded from the cylinder, and the protruding end and the base end of the cylinder are connected to one another through a bracket. In a stay damper for a swing door that supports the opening and closing of the swing door by locking one side to the swing door and the other side to the surrounding frame, the piston rod is slidably supported, and the tip of the piston rod collides with the bracket to cause damage to the inside of the cylinder. A bushing that is displaced in the axial direction toward the piston rod is held at the tip of the cylinder, and a gas passage is formed by passing through this bushing vertically, and a sealing member that is deformed and separated from the piston rod as the bushing is displaced in the axial direction is attached adjacent to the bushing. A stay damper for a swing door, characterized in that the stay damper is interposed between a cylinder and a piston rod.