JPH0372849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber used in the rear action of a two-wheeled vehicle, and more particularly to a hydraulic shock absorber in which damping force and spring load are adjusted simultaneously using the same hydraulic power source.

Hydraulic shock absorbers equipped with a damping force or spring load adjustment mechanism often have trouble operating the adjustment device due to the mounting position thereof, and therefore various devices have been developed that allow adjustment work to be performed remotely.

One such device, which is adjusted using hydraulic pressure, requires a pipe to transport the oil from the hydraulic source that supplies the pressure oil to the shock absorber, which has the disadvantage that the device itself becomes complicated.

Also, when adjusting the spring holder of a coil spring that is stretched around the outer circumference of the cylinder, for example, if the spring holder is adjusted to shorten the set length of the coil spring, the reaction force will become stronger, causing the piston rod to withdraw from the cylinder. During the extension stroke, the piston speed increases and the damping force becomes insufficient.

The present invention has been made to effectively eliminate such problems, and its purpose is to provide a hydraulic shock absorber with a simple structure that can simultaneously adjust the spring load and damping force of the coil spring. be.

In order to achieve such an object, the present invention makes it possible to freely adjust the damping force by slidably inserting an adjusting rod inside a hollow piston rod, and having one end of the adjusting rod facing into a hydraulic chamber formed inside a mounting bracket. In the hydraulic shock absorber, the mounting bracket is engaged with a spring receiver that supports one end of a coil spring stretched around the outer periphery of the cylinder, and a plunger and a casing that are slidable relative to each other are disposed on the outer periphery of the mounting bracket. , one end of the plunger is pressed against the coil spring, and the hydraulic chamber is communicated with a hydraulic chamber divided by the plunger, the casing, and the mounting bracket, and these hydraulic chambers are communicated with a hydraulic pressure source. Features.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a cutaway side view of a hydraulic shock absorber according to the present invention, FIG. 2 is an enlarged cutaway side view of the lower part of the hydraulic shock absorber, and FIG. 3 is a sectional view taken along the line 3-3 in FIG.

In the shock absorber main body 1 shown in FIG. 1, 2 is a cylinder. A hollow piston rod 3 faces inside the cylinder 2 from below, and is fitted into the upper end of the piston rod 3 so as to be slidable up and down on the inner circumference of the cylinder 2. A piston 4 is fastened with a nut 5. As shown in the figure, an oil seal 6 and a lid member 7 are fitted on the inner periphery of the lower part of the cylinder 2 so as to be in sliding contact with the outer periphery of the piston rod 3. The inside of this cylinder 2 is divided by a piston 4 into an upper chamber S ₁ and a lower chamber S ₂ , and hydraulic oil is sealed in these chambers S ₁ and S ₂ .

On the other hand, an adjustment rod 8 is fitted inside the piston rod 3 so as to be able to slide vertically, and a variable oil passage 9 is formed between the upper end of the adjustment rod 8 and the hollow rod 3 as shown in the figure. The rod 3 is provided with an oil passage 10 communicating with the variable oil passage 9 and an oil hole 11.

Further, a mounting bracket 12 is connected to the lower end of the piston rod 3.
A hydraulic chamber _S3 is formed inside the hydraulic chamber _S3 .
The adjustment rod 8 is facing. Further, a casing 13 is fixed to the outer periphery of the mounting bracket 12, and the casing 13 and the mounting bracket 1 are connected to each other.
A cylindrical plunger 14 is fitted between the two so as to be able to slide vertically, and the upper end of the plunger 14 is connected to a coil stretched around the outer circumferential side of the cylinder 2 via a cover 15, a spring receiver 16, and a spring guide 17. It is pressed against the lower end of the spring 18. The upper end of the coil spring 18 is attached to a spring receiver 19 fixed to the upper outer periphery of the cylinder 2.
is supported by

Incidentally, a hydraulic chamber S ₄ is formed below the plunger 14 and is partitioned by the plunger 14 , the mounting bracket 12 and the casing 13 , and the hydraulic chamber S ₄ is connected to the hydraulic chamber S ₃ via an oil passage 20 . It's communicating. A plug hole 21 is formed diagonally downward in the lower part of the mounting bracket 12, and an oil passage 22 communicating with the plug hole 21 is connected to the hydraulic chamber _S3.
communicate with. The hydraulic chamber S ₃ is connected to the hydraulic chamber of the pressure generator 30 which is installed separately from the shock absorber main body 1 via an oil passage 22 and a hose 23 connected to the plug hole 21.
Connected to _S5 .

The inside of the main body casing 31 of the pressure generating device 30 is divided into two spaces ΔS ₁ and ΔS ₂ by a partition wall 31a, and a motor 32 is housed in one space ΔS ₂ as shown in the figure. electrode 32
a, 32b are connected to a battery 35 via a forward/reverse switch 33 and an eddy current prevention circuit 34. This motor 32 also has a three-stage planetary gear train, upper and lower.
G ₁ , G ₂ , and G ₃ are connected. A small gear 36 is connected to the uppermost planetary gear train _G1 as shown in the figure, and a large gear 37 meshes with the gear 36.

A rotating shaft 38 facing into the space ΔS ₁ is fixed to the large gear 37, and a thread is cut on the outer periphery of the rotating shaft 38. And this rotating shaft 3
A cylindrical slider 39 is screwed into the outer circumferential threaded portion of 8 so as to be slidable up and down, and a piston 40 that is slidably fitted into the space ΔS ₁ is attached to the lower end of the slider 39 as shown in the figure. Fixed. Therefore, the space ΔS ₁
The hydraulic chamber _S5 defined by the piston 40 is formed inside the hydraulic chamber S5, and the hydraulic chamber _S5 is filled with oil.

Note that the slider 39 has a groove 39 in the axial direction on its outer periphery.
A is formed in the groove 39a, and a locking bolt 41 screwed onto the side wall of the main body casing 31 is engaged with the groove 39a, thereby preventing the slider 39 from rotating.

Then, operate the forward/reverse switch 33 to switch the motor 32.
When the motor 32 is rotated, the output shaft 32c of the motor 32 is rotated.
The rotation is reduced in three stages by the planetary gear trains G ₁ , G ₂ , and G ₃ , and further reduced in accordance with the tooth ratio between the small gear 36 and the large gear 37 , and the torque is amplified and transmitted to the rotating shaft 38 . The rotational shaft 38 is driven to rotate. Due to the rotation of the rotating shaft 38, the slider 39, which is threaded onto the outer peripheral thread of the rotary shaft 38, moves up and down, and as the slider 39 moves up and down, the piston 40 also moves up and down. The volume of the hydraulic chamber S ₅ changes. For example, piston 40
moves downward, the oil pressure in the hydraulic chamber _S5 increases,
This oil is introduced into the hydraulic chamber _S3 of the mounting bracket 12 via the hose 23 and the oil passage 22, and at the same time is introduced into the hydraulic chamber _S4 via the oil passage 20.

The pressure of the oil in the hydraulic chamber _S3 causes the adjustment rod 8 to move upward, reducing the flow area of the variable oil passage 9, increasing the flow resistance of the oil flowing therethrough, and increasing the damping force.
In addition, the pressure of the pressure oil in the hydraulic chamber S ₄ causes the plunger 14 to
is moved upward to shorten the set length of the coil spring 18 and adjust its spring load to a higher value.

As a result of increasing the spring load of the coil spring 18, the reaction force of the coil spring 18 becomes stronger, and even if the piston speed increases during the extension stroke when the piston rod 3 exits the cylinder 2, the damping force increases at the same time. Since the damping force is adjusted, the conventional problem of insufficient damping force due to an increase in piston speed can be effectively resolved.

Also, since both hydraulic chambers S ₃ and S ₄ are formed in the mounting bracket 12 and pressure oil is supplied and discharged to these hydraulic chambers S ₃ and S ₄ at the same time, the structure can be simplified and the configuration can be extremely compact. I can do it.

On the other hand, operate the forward/reverse switch 33 to
If the pressure is reversed and the slider 39 and piston 40 are moved upward, the pressure in the hydraulic chamber _S5 is reduced, and the damping force and spring load are adjusted to be low.

In addition, although the embodiment in which pressure oil is first introduced to the hydraulic chamber _S3 side has been described above, as shown in Fig. 4, the plug hole 13
a may be provided on the side wall of the casing 13 and first led to the hydraulic chamber _S4 side, but in this case, the hydraulic chamber
A drain bolt 50 is required below _S3 . As shown in Fig. 5, this drain bolt is made to be able to move forward and backward 51, and by moving it up and down, the gap Δc between the head of this drain bolt and the lower end of the adjustment rod 8 can be adjusted, and the damping force variable range can be increased or decreased. You can also do it.

As is clear from the above description, according to the present invention, the spring load and damping force of the coil spring can be adjusted simultaneously with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of a hydraulic shock absorber according to the present invention, FIG. 2 is an enlarged cutaway side view of the lower part of the shock absorber, FIG. The figure is similar to FIG. 2 according to a modified embodiment. In the drawing, 1 is the shock absorber body, 2 is the cylinder, and 3 is the shock absorber body.
is a hollow piston rod, 8 is an adjustment rod, 12 is a mounting bracket, 13 is a casing, 14 is a plunger, 16, 19 are spring receivers, 30 is a pressure generator, S ₁ , S ₂ , S ₃ , S ₄ , S ₅ are This is a hydraulic room.

Claims (1)

[Claims] 1. An adjustment rod is slidably inserted into the hollow piston rod to freely adjust the damping force, and one end of the adjustment rod is exposed to the hydraulic chamber formed inside the mounting bracket. In the hydraulic shock absorber, a plunger and a casing are disposed on the outer periphery of the mounting bracket and are mutually slidable, and one end of the plunger is press-connected to the coil spring. A hydraulic shock absorber characterized in that the hydraulic chamber defined by the plunger, the casing, and the mounting bracket communicates with the hydraulic chamber, and these hydraulic chambers communicate with a hydraulic pressure generation source.