JPH0874917A - Rebound spring structure of buffer - Google Patents

Abstract

PURPOSE: To prevent a spring end part from making any contact with the outer periphery of the rod and the inner periphery of a cylinder and restrain the generation of noise by connecting one end of a rebound spring to a cylinder opening end and other end to a holder slidable to a piston rod. CONSTITUTION: A cushion 6 rising with a rod 2 is brought in contact with the lower end of a holder 8 for supporting the lower end 3b of a rebound spring 3 under such state that a piston rod 2 is projected by its large stroke and a hydraulic buffer is nearly extended to the utmost. From this state, when the piston rod 2 is further projected from the inside of a cylinder 1 and reaches its most extended state, this projection is restrained by the energizing force of the rebound spring 3 and then cushion effect is displayed. At this time, the upper end 3a of the rebound spring 3 is connected to the guide part 5a of a bearing 5 which is a fixed end and its lower end 3b is interposed to the rod 2 through the holder 8. Therefore, the upper end 3a and the lower end 3b become so called loose and the contact to the inner periphery of the cylinder 1 and the outer periphery of the piston rod 2 is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber rebound spring structure suitable for use in a hydraulic shock absorber.

[0002]

2. Description of the Related Art As is well known, a rebound spring in a shock absorber represented by a hydraulic shock absorber has a piston rod which is inserted into the cylinder when the shock absorber is fully extended, that is, in the cylinder. When the piston rod is in the most protruding state, the piston rod collides with the cylinder, that is, to be precise, it is a closing member that closes the open end of the cylinder by the piston portion connected to the tip of the piston rod. It functions to prevent the bearing from hitting.

The rebound spring is disposed in the cylinder so as to be interposed in the outer periphery of the piston rod, and when the shock absorber is fully extended, one end thereof is in contact with the lower end of the bearing. At the same time, the lower end, which is the other end, is set to abut on a cushion made of rubber or the like arranged on the outer periphery of the piston rod near the piston portion.

The cushion is usually supported from below by a support fixed to the outer periphery of the piston rod near the piston portion.

There have been various proposals for the arrangement of the rebound spring, but the simplest structure is that the rebound spring is only loosely fitted around the outer circumference of the piston rod. It

With this structure, the rebound spring can be easily arranged and the assembly workability of the shock absorber is not deteriorated, but the rebound spring is placed in a so-called idle state on the outer circumference of the piston rod. .

Therefore, when the piston rod moves in and out of the cylinder, that is, when the shock absorber expands and contracts, the rebound spring moves and comes into contact with the outer circumference of the piston rod and the inner circumference of the cylinder. There is a risk of causing damage to the inner circumference of the cylinder.

When the outer circumference of the piston rod is damaged, the seals arranged on the opening end side of the cylinder and the inner circumference of the cylinder are damaged. In this case, the seals arranged on the outer circumference of the piston part will be worn due to the scratches, etc.
The predetermined sealing property will be impaired in a short period of time.

Inconvenience resulting from the fact that the rebound spring is inserted in a loosely fitted state, that is, the rebound spring moves when the shock absorber expands and contracts, and the rebound spring is attached to the outer circumference of the piston rod and the inner circumference of the cylinder. In order to eliminate the contact, the following measures have been conventionally adopted.

As a measure for preventing the movement of the rebound spring, for example, the upper end, which is one end of the rebound spring, is set in the expanding tendency, and the upper end of the rebound spring set in the expanding tendency is set within the opening end of the cylinder. There is a way to press it into the circumference.

In the case of this measure, the lower end, which is the other end of the rebound spring, is set in a so-called throttling tendency so as not to contact the inner circumference of the cylinder, and in a so-called free state where it is not particularly restricted. Get burned.

Therefore, in the case of this measure, the rebound spring only needs to be machined in a predetermined manner, and no other so-called parts are required. Therefore, the rebound spring is not inconvenienced due to an increase in the number of parts. It will be possible to prevent movement.

However, the damage phenomenon on the outer circumference of the piston rod and the inner circumference of the cylinder due to the upper end of the rebound spring and the damage phenomenon on the inner circumference of the cylinder due to the lower end of the rebound spring are effectively prevented. As always, there is a concern that the lower end of the rebound spring may cause a scratch on the outer circumference of the piston rod.

On the other hand, it is needless to say that the upper and lower ends of the rebound spring do not contact the inner circumference of the cylinder, but in order to prevent the upper and lower ends of the rebound spring from contacting the outer circumference of the piston rod. For example, there is a measure in which the upper end and the lower end of the rebound spring are respectively interposed in spring receivers that serve as spring guides, and the rebound spring is interposed with a so-called gap on the outer circumference of the piston rod via the spring receivers.

Of course, the pair of upper and lower spring receivers do not have their outer circumferences in contact with the inner circumference of the cylinder, but their inner circumferences are not slidably contacted with the outer circumference of the piston rod. Therefore, the outer circumference of the piston rod is integrated with the rebound spring in a so-called loose fitting state.

Therefore, in the case of this measure, it is possible to completely prevent the upper end and the lower end of the rebound spring from coming into contact with the inner circumference of the cylinder and the outer circumference of the piston rod. There is an advantage that inconvenience such as abrasion is not caused.

However, when utilizing a pair of upper and lower spring receivers, the rebound spring is so-called idle around the outer circumference of the piston rod, so that the spring moves along with the piston rod when the shock absorber expands and contracts. The receiver collides with a bearing that is a closing member that closes the open end of the cylinder.

Therefore, it is pointed out that so-called noise is generated due to repeated collision of the spring bearing with the bearing.

The present invention was devised in view of the above-mentioned circumstances, and an object thereof is not only to provide a predetermined shock relaxation when the shock absorber is fully extended, but also to expand and contract the shock absorber. Sometimes the upper and lower ends of the rebound spring do not contact the outer circumference of the piston rod or the inner circumference of the cylinder, and
It is an object of the present invention to provide a rebound spring structure for a shock absorber, which is optimal for use in a hydraulic shock absorber without causing noise due to collision with other parts of the rebound spring.

[0020]

In order to achieve the above-mentioned object, the structure of the present invention is adopted in a piston rod in a cylinder when a shock absorber in which a tip end side of the piston rod is inserted into and retractable from the cylinder is fully extended. In the rebound spring structure of the shock absorber, the rebound spring structure includes a rebound spring that prevents the piston portion connected to the tip of the piston rod from colliding with the closing member that is interposed on the outer periphery of the cylinder and closes the opening end of the cylinder. One end of the spring is connected to a fixed portion arranged on the inner peripheral side of the opening end of the cylinder, and the other end of the rebound spring is connected to a holder slidably mounted on the piston rod. It is a thing.

More specifically, the fixing portion serves as a guide portion of a bearing that closes the inner peripheral side of the opening end of the cylinder and allows the piston rod to pass through the axial center portion thereof, and rebounds to the outer periphery of the guide portion. It is assumed that one end of the spring is fitted.

Further, the fixed portion is press-fitted on the inner peripheral side of the open end of the cylinder so as to be in series with the bearing and serves as a guide portion in a stopper which has a gap in its shaft portion and penetrates the piston rod. It is assumed that one end of the rebound spring is fitted on the outer circumference of the guide portion.

The holder is formed so as to have a seat portion for supporting the lower end of the rebound spring and a guide portion for penetrating the piston rod in a loosely fitted state, and the other end of the rebound spring is provided on the outer periphery of the guide portion. It is supposed to be fitted.

[0024]

Therefore, one end of the rebound spring is connected to the guide portion of the bearing as the fixed portion or the guide portion of the stopper to prevent contact with the inner circumference of the cylinder and the outer circumference of the piston rod. Overall up-and-down movement is prevented in a state where it is interposed on the outer circumference of the piston rod.

At this time, the inner diameter of one end of the rebound spring is set to be smaller than the outer diameter of the guide portion, and the rebound spring is fitted into each of the guide portions.

Further, the other end of the rebound spring is connected to a holder which is inserted in the outer periphery of the piston rod in a loosely fitted state, whereby contact with the inner periphery of the cylinder and the outer periphery of the piston rod is prevented.

At this time, the inner diameter of the other end of the rebound spring is set to be smaller than the outer diameter of the guide portion of the holder, and the rebound spring is fitted into the guide portion.

Then, the rebound spring is compressed by pressing the cushion when the piston rod is in a state close to the fully extended state of the shock absorber in which the piston rod largely projects from the inside of the cylinder, and the biasing force at this time compresses the predetermined cushion. Be effective.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the illustrated embodiment. A hydraulic shock absorber as a shock absorber according to this embodiment is inserted into a cylinder 1 so that the tip end side of a piston rod 2 can be retracted. In the cylinder 1, the rebound spring 3 is provided on the outer circumference of the piston rod 2.

In addition, the hydraulic shock absorber is shown in the illustrated example,
It is configured as a multi-cylinder type having an outer cylinder 4 on the outer circumference of the cylinder 1, and a reservoir chamber R is formed between the outer cylinder 4 and the cylinder 1. It is supposed that the piston side chamber (not shown) defined by (not shown) is communicated with the piston side chamber (not shown) via a base valve portion (not shown).

The base valve portion is provided with predetermined valves (not shown).

The piston portion is slidably accommodated in the cylinder 1 and is connected to the tip of the piston rod 2 (not shown). The piston portion faces the piston side chamber in the cylinder 1. The rod-side chamber A shown in FIG.

Incidentally, the rebound spring 3 is arranged in the rod side chamber A.

The piston portion allows the piston side chamber and the rod side chamber A to communicate with each other under the presence of a damping valve (not shown).

On the other hand, the piston rod 2 is formed by penetrating a closing member which closes an opening end which is an upper end of the cylinder 1, that is, a shaft core portion of the bearing 5, and the bearing 5 forms the outer cylinder 4 The upper end of is also blocked.

The piston rod 2 is provided with a cushion 6 made of rubber or the like on the outer periphery near the piston portion, and the cushion 6 is fixed to the outer periphery of the piston rod 2 below the cushion 6. 7 is supported from below.

Incidentally, the rebound spring 3 is set so that the lower end of the rebound spring 3 is in contact with the upper end surface of the cushion 6 under the interposition of the holder 8 described later when the hydraulic shock absorber is fully extended.

In the hydraulic shock absorber formed as described above, the rebound spring 3 is arranged under the following structure.

That is, in the illustrated example, the rebound spring 3
Has an upper end 3a, which is one end thereof, connected to a fixed portion disposed on the inner peripheral side of the opening end of the cylinder 1, that is, a guide portion 5a of the bearing 5 that is a closing member that closes the opening end of the cylinder 1. .

The lower end 3b, which is the other end, of the rebound spring 3 is connected to a holder 8 slidably inserted in the piston rod 2.

Incidentally, it goes without saying that the holder 8 is arranged above the cushion 6 arranged on the outer circumference of the piston rod 2 close to the piston portion.

In the illustrated example, the holder 8 is made of a synthetic resin material so that the slidability with respect to the piston rod 2 can be easily ensured.

Guide portion 5a of the bearing 5
Is formed in a cylindrical shape so that the piston rod 2 penetrates the shaft center portion thereof, and is formed to have an appropriate thickness in the radial direction so as to have a predetermined strength. ing.

Therefore, when the upper end 3a of the rebound spring 3 is set to have a diameter slightly smaller than the outer diameter of the guide portion 5a, the upper end 3a is pushed into the outer periphery of the guide portion 5a, thereby It is possible to fit the guide portion 5a.

As a result, the upper end 3a of the rebound spring 3 is connected to the open end side of the cylinder 1 and cannot move on the outer circumference of the piston rod 2, and it goes without saying that it does not contact the outer circumference of the piston rod 2. The inner circumference of the cylinder 1 will not come into contact.

On the other hand, the holder 8 is formed to have a seat portion 8a carrying the lower end 3b of the rebound spring 3 and a guide portion 8b for penetrating the piston rod 2 in a loosely fitted state.

Also in this holder 8, the seat portion 8a and the guide portion 8b are formed so as to have a predetermined strength.

Therefore, like the upper end 3a of the rebound spring 3 described above, the lower end 3b of the rebound spring 3 is held by the holder 8.
When the outer diameter of the guide portion 8b is set to be slightly smaller than the outer diameter of the guide portion 8b, by pushing the lower end 3b into the outer periphery of the guide portion 8b, the lower end 3b can be fitted into the holder 8.

As a result, the lower end 3b of the rebound spring 3 cannot move laterally on the outer circumference of the piston rod 2, and therefore the outer circumference of the piston rod 2 does not come into contact with the inside of the cylinder 1. It will not touch the lap.

Therefore, in the hydraulic shock absorber of this embodiment formed as described above, the piston rod 2 projects from the inside of the cylinder 1 when the hydraulic shock absorber is extended.

At this time, when the piston rod 2 is projected with a large stroke and the hydraulic shock absorber is in a state of being almost fully extended, the cushion 6 rising together with the piston rod 2 in the cylinder 1 carries the lower end 3b of the rebound spring 3. It contacts the lower end of the holder 8.

From this state, when the piston rod 2 is further projected from the inside of the cylinder 1 and is in the fully extended state, the cushion 6 which has been raised against the urging force of the rebound spring 3, that is, the piston rod 2 is moved upward. The protrusion from the inside of the cylinder 1 is suppressed by the urging force of the rebound spring 3, and at this time, the speed at which the piston rod 2 protrudes from the inside of the cylinder 1 is weakened, and a so-called cushion effect is exerted.

When the force when the piston rod 2 projects from the inside of the cylinder 1 and the urging force of the rebound spring 3 are balanced, the piston rod 2 projects from the inside of the cylinder 1, that is, the hydraulic shock absorber. Extension is stopped.

When the hydraulic shock absorber is extended, the upper end 3a of the rebound spring 3 is connected to the guide portion 5a of the bearing 5 which is the fixed portion, and the lower end 3 of the rebound spring 3 is also fixed.
Since b is interposed in the piston rod 2 via the holder 8, the upper end 3a and the lower end 3b do not play so-called idle and contact the inner circumference of the cylinder 1 or the outer circumference of the piston rod 2.

When the hydraulic shock absorber in the fully extended state is reversed in the compression direction, the cushion 6 descends in the cylinder 1 as the piston rod 2 descends in the cylinder 1, and the cushion 6 moves downward. When it descends, the rebound spring 3 returns to the old state due to its urging force.

Then, with further compression of the hydraulic shock absorber,
The cushion 6 is separated from the lower end 3b of the rebound spring 3, the rebound spring 3 is in a so-called fully extended state, and the lower end 3b of the rebound spring 3 is in a so-called free state.

At this time, since the upper end 3a of the rebound spring 3 is connected to the guide portion 5a of the bearing 5 which is the fixed portion, the lower end 3b thereof is interposed between the piston rod 2 and the holder 8. The upper end 3a and the lower end 3b are so-called idle so that the inner circumference of the cylinder 1 and the piston rod 2
Do not touch the outer circumference of.

In the case of this embodiment, the bearing 5
Since it is sufficient to partially change the design, it is advantageous in that the desired purpose can be achieved without increasing the so-called number of parts.

FIG. 2 shows a hydraulic shock absorber according to another embodiment of the present invention, but only the arrangement structure of the rebound spring 3 is different from the above-mentioned embodiment.

Therefore, in this embodiment, the parts having the same constructions as those of the above-mentioned embodiments are designated by the same reference numerals in the drawings except where necessary, and the description thereof will be omitted. The features of this embodiment will be described below.

That is, in this embodiment, the upper end 3a, which is one end of the rebound spring 3, is inserted into the stopper 9 as a fixed portion which is press-fitted to the inner peripheral side of the opening end of the cylinder 1 so as to be in series with the bearing 5. It is supposed to be fitted.

Incidentally, the lower end 3b, which is the other end of the rebound spring 3, is connected to a holder 8 slidably inserted in the piston rod 2 as in the above-described embodiment.

In this embodiment, the stopper 9 forming the fixed portion is formed in a shape that is substantially symmetrical to the holder 8, and the upper end 3a of the rebound spring 3 is locked to open the cylinder 1. It is formed to have a press-fitting portion 9a which is press-fitted in series with the bearing 5 on the inner peripheral side of the end, and a guide portion 9b which penetrates the piston rod 2 in a loosely fitted state.

The stopper 9 in this embodiment is
The inner peripheral side of the guide portion 9b is set to have a positive gap 9c between the outer peripheral surface of the piston rod 2 and the so-called air bleeding from the rod side chamber A.

The press-fitting portion 9a and the guide portion 9b of the stopper 9 are formed to have a predetermined strength, and the press-fitting portion 9a is in series with the bearing 5 on the inner peripheral side of the opening end of the cylinder 1. Thus, the guide portion 9b allows the rebound spring 3 to be fitted to the outer periphery of the upper end 3a.

Incidentally, when the upper end 3a of the rebound spring 3 is fitted on the outer periphery of the guide portion 9b, the inner diameter of the upper end 3a of the rebound spring 3 is set to be slightly smaller than the outer diameter of the guide portion 9b. Of course.

Therefore, even in this embodiment, the rebound spring 3 has its upper end 3a and lower end 3b not in contact with the outer circumference of the piston rod 2 and the inner circumference of the cylinder 1 when the hydraulic shock absorber expands and contracts. Become.

In the case of this embodiment, as compared with the above-mentioned embodiment, the stopper 9 forming the fixing portion is required as an extra component, so to speak, but when the hydraulic shock absorber is assembled, it is assembled. Since the rebound spring 3 having the upper end 3a previously connected with the stopper 9 and the lower end 3b previously connected with the holder 8 can be so-called incorporated, it is possible to reduce the assemblability of the hydraulic shock absorber. It is advantageous in that it is not allowed.

[0069]

As described above, according to the present invention, the rebound spring provided on the outer circumference of the piston rod in the cylinder is connected at its upper end to the fixed portion on the opening end side of the cylinder, and Since the lower end of the piston rod is inserted into the outer circumference of the piston rod with the holder interposed, the upper and lower ends of the shock absorber, which is a hydraulic shock absorber, are in a so-called play state when the shock absorber expands and contracts. The contact with the outer circumference of the rod is prevented in advance, so that the inner circumference of the cylinder and the outer circumference of the piston rod are not damaged by the above contact, and noise is generated due to the vertical movement of the rebound spring. There is an advantage of disappearing.

Further, according to the first embodiment of the present invention, it is possible to implement the bearing only by partially changing the design of the bearing, which causes a disadvantage that the assembly process of the shock absorber is significantly changed. There is an advantage not to.

According to the second embodiment of the present invention,
It becomes possible to assemble the rebound spring in a step different from the step of assembling the shock absorber, and at the time of assembling the shock absorber, it is possible to dispose by simply incorporating the rebound spring in the assembled state. There is an advantage that the assembly workability of the container is not deteriorated.

As a result, according to the present invention, not only the shock when the shock absorber is fully extended is alleviated, but also when the shock absorber expands and contracts, the upper and lower ends of the rebound spring are located at the outer periphery of the piston rod and the cylinder. Since there is no contact with the circumference and no noise is generated due to collision with other parts of the rebound spring, there is an advantage that it is optimal for use in a hydraulic shock absorber.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 shows a hydraulic shock absorber according to another embodiment of the present invention.
It is a front view shown similarly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 cylinder 2 piston rod 3 rebound spring 5 bearing 5a as a closing member 5a guide part in bearing used as a fixed part 8 holder 9 stopper forming a fixed part 9b guide part

Claims (3)

[Claims] Claim: What is claimed is: 1. A piston rod is inserted into the outer periphery of the piston rod in the cylinder to close the opening end of the cylinder when the shock absorber having the tip end side of the piston rod inserted into and retractable from the cylinder is fully extended. In a rebound spring structure of a shock absorber having a rebound spring that prevents a continuous piston part from colliding with the tip of a fixed part, one end of the rebound spring is arranged on the inner peripheral side of the opening end of the cylinder. And a rebound spring structure of a shock absorber in which the other end of the rebound spring is connected to a holder slidably inserted in the piston rod. 2. The fixed portion serves as a guide portion of a bearing that closes the inner peripheral side of the open end of the cylinder and has a shaft core portion that penetrates the piston rod, and one end of the rebound spring is fitted to the outer periphery of the guide portion. The rebound spring structure for a shock absorber according to claim 1, wherein the rebound spring structure is attached. 3. A fixed portion is press-fitted on the inner peripheral side of the opening end of the cylinder so as to be in series with the bearing, and has a gap in its shaft portion to serve as a guide portion in a stopper for penetrating the piston rod. 2. A rebound spring structure for a shock absorber according to claim 1, wherein one end of the rebound spring is fitted around the outer periphery of the guide portion.