JPH0520909Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is for vehicles such as automobiles and motorcycles,
This relates to a hydraulic shock absorber that is installed between the vehicle body and the axle to absorb vibrations and shocks from the road surface.

[Prior Art] A hydraulic shock absorber that serves as a shock absorber and a fork is interposed between the body and the front axle of a motorcycle.

As this hydraulic shock absorber, for example, the one shown in FIG. 4 has been developed (Japanese Patent Application No. 1983-93968).

In this hydraulic shock absorber, an inner tube 2 is slidably inserted into a rotatable outer tube 1 via a piston 3, and a valve housing 15 provided with a valve 11 is movably inserted into the inner tube 2. The inner tube 2 is always urged in the direction of extension via suspension springs A and B.

The upper end of the suspension spring A is supported by a cap 6 on the inner tube 2 side via a washer 4 and a thrust bearing 5.

[Problems to be solved by the invention] Since the inner tube 2 is attached to a vehicle body such as a motorcycle, its rotation with respect to the vehicle body is limited, whereas the outer tube 1 is rotatable with respect to the vehicle body, It rotates with respect to the inner tube 2 as it is steered. As the inner tube 2 expands and contracts, the suspension springs A and B also expand and contract, but at this time, the suspension springs A and B also tend to move slightly in the rotational direction. In this way, if the outer tube 1 rotates or the suspension springs A and B
When rotates and expands and contracts, suspension springs A and B move in the rotational direction via washers 4 and thrust bearings 5, but the contact area of the thrust bearings is large, the friction of the thrust bearings 5 becomes large, and the outer tube There is a problem that the rotation of the tube 1 and the expansion/contraction operation of the inner tube 2 are not smooth.

Also, the friction coefficient between the thrust bearing 5 and the washer 4 is μ, the spring force of suspension springs A and B is p,
When the distance from the center of the thrust bearing 5 to the sliding part on which the suspension spring A slides is r, the rotational torque T due to the frictional force is T=μpr, and the friction increases in proportion to the distance r.

Therefore, an object of the present invention is to provide a hydraulic shock absorber that can reduce the friction of a spring guide that supports a suspension spring.

[Means for solving the problem] In order to achieve the above purpose, the configuration of the present invention is as follows.
An inner tube is slidably inserted into a rotatable outer tube, a valve body is slidably inserted into the inner tube, and two oil chambers are partitioned into the inner tube and the outer tube by the valve body. The two oil chambers are opened and closed by a port provided in the valve body and a valve for generating damping force placed at the mouth end of the port, and the valve body is opened and closed from both sides by multiple suspension springs arranged in series in the inner tube and outer tube. In the clamped hydraulic shock absorber, a spherical support member is provided at the end of the valve body, one end of the suspension spring is supported by a spring guide, and the spherical surface of the support member is brought into contact with the center of the spring guide. It is characterized by supporting a spring load.

[Operation] When the suspension spring rotates via the spring guide, the contact area between the support member and the spring guide is small, and the distance from the center of the support member to the contact point between the two is small, so the rotational torque is small. , the friction of the spring guide becomes smaller. Therefore, the rotation of the suspension spring becomes smooth, and the rotation of the outer tube and the expansion/contraction operation of the inner tube become better.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows an embodiment of the present invention, and the hydraulic shock absorber is constructed as follows.

That is, the inner tube 23 is slidably inserted into the rotatable outer tube 21, the valve body composed of the rod 41, the valve housing 36, and the piston 35 is slidably inserted into the inner tube 23, and the inner tube 23 is slidably inserted into the inner tube 23. tube 2
3 and the outer tube 21 are divided into two oil chambers 30 and 31 separated by the valve body. It is opened and closed by a pressure valve 38 which is a generating valve, and the valve body is held from both sides by two upper and lower suspension springs 45 and 46 arranged in series within the inner tube 23 and outer tube 21.
A sphere 50 serving as a spherical support member is provided at the end of the rod 41 constituting the valve body, and the upper end of the suspension spring 48 is supported by a spring guide 49. A sphere 50 is provided at the center of the spring guide 49.
The spring load is supported by contacting the spherical surface of the
This will be explained in more detail below.

An inner tube 23 is slidably inserted into a rotatable outer tube 21 via a piston 22, and the outer tube 21 is inserted into the bracket 2.
The cap 2 is connected to the wheel side of a motorcycle or the like via the cap 2 and connected to the upper end of the inner tube 23.
5 is connected to an eye bracket 26, and the eye bracket 26 is connected to the vehicle body side.

The inner tube 23 penetrates to the outside via a bearing 27, an oil seal 28, and a dust seal 29, and the piston 22 has oil chambers 30 and 31 defined within the outer tube 21.

The two upper and lower oil chambers 30 and 31 communicate through a through hole 32 provided in the inner tube 23, and the through hole 3
An extension valve 33 for generating an extension damping force is provided at the upper mouth end of the cylinder 2 so as to be openable and closable, and a spring 34 for a cushion is built in the upper oil chamber 30.

A valve housing 36 is movably inserted into the inner tube 23 via a piston 35 , and a pressure boat 37 is formed in the valve housing 36 . are communicating.

A rod 41 is inserted through the center of the valve housing 36, and the lower part of the rod 41 is connected to the rod head 4.
2 to the lower surface of the valve housing 36.

A pressure valve 38 for generating compression side damping force is provided at the upper mouth end of the pressure boat 37 so as to be openable and closable.This pressure valve 38 is biased in the closing direction via a valve holder 41 and a spring 39. It is supported by a spring seat 43 screwed into the spring seat 41.

A gas chamber 44 containing air or the like is defined in the upper part of the inner tube 23 .

An upper suspension spring 45 inserted into the inner tube 23 is held between the cap 25 and the piston 35.

A spring seat 46 and a hollow oil hole rod 47 are held at the lower part of the outer tube 21, and the spring seat 46 supports the lower part of the lower suspension spring 48.

The upper part of the suspension spring 48 is supported by a spring guide 49 having a V-shaped cross section, and the center of the spring guide 49 is supported by the flange 42 of the rod 41 via a support member made of a sphere 50.

The oil hole rod 47 is fitted with the lower part 23a of the inner tube 23 near the most compressed position of the inner tube 23, thereby making the cushion effective.

The two upper and lower suspension springs 45 and 47 always urge the inner tube 23 in the direction of extension.

The sphere 50 is a groove 5 provided in the lower part of the rod head 42.
A part of the spherical surface of the sphere 50 rotatably contacts the spring guide 49 and the sliding part 52 . Since the spherical body 50 is in contact with the spring guide 49 through a part of the spherical surface, the contact area is small, and moreover, the contact area 5
The distance r' to 2 is short. Therefore, the friction between the sphere 50 and the spring guide 49 becomes small.

Now, when μ is the friction coefficient of the sphere 50 made of metal steel balls, p is the spring force of the lower suspension spring 48, and T is the rotational torque, T = μ・p・r′, and since r′ is short, , the rotational torque becomes smaller.

Therefore, even when the suspension spring 48 expands and contracts during a telescopic operation and rotational force is generated, or when the outer tube 21 rotates and rotational force is generated in the suspension spring 48 as during steering, the rotational torque of the spring guide 49 is Since it is small and the contact area is small, there is less friction, and the expansion and contraction of the inner tube 23 and the rotation of the outer tube 21 are smooth.

FIG. 3 shows another embodiment of the present invention, in which a rod with a spherical end is used as the support member. The other configurations are exactly the same as in FIG.

That is, a spherical surface 50a is formed at the lower part of the rod head 42a, the rod head 42a is configured as a spherical support member, and the center of the spring guide 49 is rotatably supported by the spherical surface 50a.
In this case as well, since the contact portion is spherical, the contact area is small and the distance from the center to the contact portion can be shortened, so that the same functions and effects as above can be obtained.

In addition, when the spring guide 49 is V-shaped or flat as shown in the figure, it is preferable to use a spherical support member, but when the spring guide 49 is only V-shaped, the support member is It may be columnar or cylindrical.

[Effects of the invention] In this invention, since the contact area of the support member is small and the distance from the center to the contact part is small, the friction between the support member and the spring guide is small, and the action of the suspension spring in the rotational direction is smooth, resulting in an inner tube. The expansion and contraction operation of the outer tube and the rotational movement of the outer tube become smooth.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of a hydraulic shock absorber according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the spring guide portion of FIG. 1, and FIG. 3 is a hydraulic shock absorber according to another embodiment of the present invention. FIG. 3 is a partially longitudinal front view of the shock absorber. FIG. 4 is a partially cutaway front view of a conventional hydraulic shock absorber. 21... Outer tube, 23... Inner tube, 45, 48... Suspension spring, 49
...Spring guide, 50...Sphere, 50a...
...Spherical surface.

Claims (1)

[Claims for Utility Model Registration] (1) An inner tube is slidably inserted into a rotatable outer tube, a valve body is slidably inserted into the inner tube, and the valve body is inserted into the inner tube and the outer tube. Two oil chambers are divided by
The two oil chambers are opened and closed by a port provided in the valve body and a valve for generating damping force placed at the mouth end of the port, and the valve body is held from both sides by multiple suspension springs placed in series in the inner tube and outer tube. In a conventional hydraulic shock absorber, a spherical support member is provided at the end of the valve body, one end of the other suspension spring is supported by a spring guide, and the spherical surface of the support member is brought into contact with the center of the spring guide to release the spring. A hydraulic shock absorber characterized by supporting a load. (2) The hydraulic shock absorber according to claim 1, wherein the valve body is composed of a rod, a valve housing inserted into the rod, and a piston provided on the outer periphery of the valve housing, and a port is formed in the valve housing. . (3) The hydraulic shock absorber according to claim 1, wherein the support member is spherical. (4) The hydraulic shock absorber according to claim 2, wherein the support member is formed by the head of a rod with a spherical surface formed at the lower part. (5) The hydraulic shock absorber according to claim 1, wherein the spring guide has a V-shaped cross section.