JP2003247585A - Hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a friction giving action of a hydraulic shock absorber capable of quickly rising temperature for tires of a vehicle from a low temperature side. <P>SOLUTION: In the hydraulic shock absorber 10, an O-ring retaining portion 70 is incidentally arranged at an oil chamber 12 side closer than an oil seal 16 in a rod guide 14, an O-ring groove 75 arranged on the O-ring retaining portion 70 is filled with an O-ring 60 at a filling rate of 88 to 98%, and friction is given to a piston rod 13 by the O-ring 60. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Laid-Open No. 2001-159443, there is a device which is provided with a friction member for imparting friction to a piston rod of a hydraulic shock absorber so as to ensure maneuverability and stability of a vehicle. .

[0003]

Generally, in a vehicle for racing, it is necessary to raise the tire temperature to enhance the grip force and to travel. The present inventor immediately raises the temperature of the tire, which has become low at the time of the primary stop during the race, at the time of re-driving. It was acknowledged that it is necessary to heat the tire by increasing the load of force.

However, the temperature t of the conventional hydraulic shock absorber is
And the friction f given by the hydraulic shock absorber is shown in FIG.
It is like the experimental results shown in. On the low temperature side of the hydraulic shock absorber, the friction f is high due to the physical properties of the seal and the like when the viscosity of the hydraulic oil is high, but when the hydraulic shock absorber becomes hot, the viscosity of the hydraulic oil decreases, so the friction of the friction member is reduced. It is presumed that a high friction f cannot be obtained due to the imparting action. Attempting to secure a high friction f by the friction member on the high temperature side of the hydraulic shock absorber is not appropriate because the friction f on the low temperature side of the hydraulic shock absorber becomes excessive.

Therefore, at the time of the primary stop after the hydraulic shock absorber has become hot due to running, the friction f of the hydraulic shock absorber tends to be further lowered after the air cooling effect of the traveling wind disappears and becomes higher. It is not possible to expect a high friction imparting action that immediately raises the tire temperature when the vehicle is re-run. That is, the conventional hydraulic shock absorber is not suitable for increasing the tire temperature.

An object of the present invention is to obtain the friction imparting action of the hydraulic shock absorber so that the tire temperature of the vehicle can be quickly raised from the low temperature side.

[0007]

According to a first aspect of the invention, a piston rod inserted into an oil chamber provided in a cylinder is led out to the outside through a rod guide and an oil seal provided in an opening of the cylinder. In this hydraulic shock absorber, a holding portion for a friction member made of an elastic material is additionally provided on the oil chamber side of the oil seal in the rod guide, and the groove made in the holding portion for the friction member made of the elastic material is made of the elastic material. The friction member is filled at a filling rate of 88 to 98%, and friction is applied to the piston rod by the friction member made of this elastic material.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the holding portion of the friction member made of the elastic material is provided with a communication passage that connects the groove and the oil chamber.

According to a third aspect of the present invention, in addition to the first or second aspect, the holding portion of the friction member made of the elastic material is made of an elastic material having a holding recess for the friction member made of the elastic material. A holding member for the friction member and a lid member for covering the recess of the holding member for the friction member made of an elastic material are formed, and the recess covered by the lid member is the groove.

According to a fourth aspect of the present invention, in addition to the first to third aspects, the friction member made of the elastic material is an O-ring.

[0011]

FIG. 1 is a sectional view showing a hydraulic shock absorber,
2 is an enlarged sectional view of an essential part of FIG. 1, FIG. 3 is a sectional view showing an O-ring holding member and a lid, FIG. 4 is a schematic view for explaining a filling rate of an O-ring, and FIG. 5 is a hydraulic shock absorber according to the present invention. FIG. 6 is a diagram showing a temperature-friction relationship, and FIG. 6 is a diagram showing a temperature-friction relationship of the hydraulic shock absorber in the conventional example.

The hydraulic shock absorber 10 is of a single tube type, and has a piston rod 13 inserted into an oil chamber 12 provided in a cylinder 11, a bush 15 of a rod guide 14 screwed into an opening of the cylinder 11, and a rod. The guide 14 is slidably contacted with an oil seal 16 loaded in a recess 14A formed in the lower portion of the bush 15 and is led out to the outside. An O-ring 17 is provided on the outer circumference of the rod guide 14.

A wheel-side mounting member 21 is provided at the lower end of the cylinder 11, and a lower spring seat 22 and its lock nut 23 are screwed onto the outer periphery of the cylinder 11. A vehicle body side mounting member 24 is fixed to the outer end portion of the piston rod 13 together with a lock nut 25, an upper spring seat 26 is fixed to the outer periphery of the vehicle body side mounting member 24, and a lower portion of the vehicle body side mounting member 24 in the piston rod 13 is fixed. A bump rubber 27 is provided in a portion surrounded by the upper spring seat 26. A suspension spring (not shown) is interposed between the lower spring seat 22 and the upper spring seat 26.

A piston valve device 31 is provided at the inner end of the piston rod 13 inserted into the cylinder 11. The piston valve device 31 uses the piston 32 fixed to the end of the piston rod 13 to separate the oil chamber 12 of the cylinder 11 into a rod-side oil chamber 12A in which the piston rod 13 exists and a piston-side oil chamber in which the piston rod 13 does not exist. The expansion side flow passage 33 and the compression side flow passage 34, which are partitioned into the chamber 12B and allow the piston rod side oil chamber 12A and the piston side oil chamber 12B to communicate with each other, are provided in the piston 32, and the opening of the extension side flow passage 33 can be opened and closed. Expansion side deflection valve 35 and compression side flow path 3
4 is configured to include a compression side bending valve 36 that can open and close the opening of No. 4. In the extension stroke of the piston rod 13, the piston valve device 31 flexibly deforms the extension side flexible valve 35 by the flow of the working oil that moves from the rod side oil chamber 12A to the piston side oil chamber 12B through the extension side flow passage 33. The expansion side damping force is generated, and in the compression stroke of the piston rod 13, the compression side deflection valve 36 is flexibly deformed by the flow of hydraulic oil that moves from the piston side oil chamber 12B to the rod side oil chamber 12A through the compression side flow passage 34. To generate a damping force on the compression side.

A reservoir tank 42 is connected to the lower portion of the cylinder 11 via a connecting portion 41. Reservoir tank 4
Reference numeral 2 denotes a movable partition member 44 slidably contacting the inside sealed by a cap 43 in a vertically movable manner, the upper part of the movable partition member 44 is a pressurized gas chamber 45, and the lower part of the movable partition member 44 is a reservoir chamber. 46 between the reservoir chamber 46 and the piston side oil chamber 12B of the cylinder 11.
7 is provided. The base valve device 47 includes the cylinder 1
The base side piston 48 is provided at the connecting portion between the communication portion 41 of No. 1 and the reservoir tank 42, and the pressure side flow passage 49 and the extension side flow passage 50 that allow the piston side oil chamber 12B and the reservoir chamber 46 to communicate with each other.
Is provided in the base piston 48, and is provided with a compression side deflection valve 51 that can open and close the opening of the compression side flow path 49, and an expansion side check valve 52 that can open and close the opening of the expansion side flow path 50. The base valve device 47 includes the piston rod 1
In the compression stroke of No. 3, the pressure side is generated by the flow of hydraulic oil that moves from the piston side oil chamber 12B to the reservoir chamber 46 through the pressure side flow passage 49 so as to compensate for the volume of oil of the piston rod 13 that enters the cylinder 11. The flexible valve 51 is flexibly deformed to generate a compression side damping force. In the extension stroke of the piston rod 13, the volume of oil of the piston rod 13 that exits from the cylinder 11 is supplied from the reservoir chamber 46 to the extension side flow path 5.
0, piston side oil chamber 1 through extension side check valve 52
Supply to 2B.

Therefore, in the hydraulic shock absorber 10, when the vehicle is running, the suspension spring absorbs the impact force received from the road surface of the vehicle, and the accompanying expansion and contraction vibration of the suspension spring is absorbed by the piston valve device 31 and the base valve. Vibration is damped by the above-mentioned damping force generated by the device 47.

However, in this embodiment, in order to improve the maneuverability and stability of the vehicle, the friction member O made of an elastic material that gives the piston rod 13 friction is used.
The ring 60 is built in the rod guide 14 as follows.

That is, as shown in FIG. 2, the rod guide 14
In the lower part on the oil chamber 12 side with respect to the oil seal 16 (recess 14A) in FIG.
The ring holding member 71 and the lid member 72 are loaded in an overlapping state, and a stopper 73 screwed from the lower end side of the recess 14B is applied to a flange portion 71B of the O ring holding member 71, which will be described later, to these O ring holding members 71. And the lid member 72 in the recess 14
It is sandwiched by the stepped portion on the back side of B. The stopper 73 has a ring shape and has tool insertion holes 73A at a plurality of positions in the circumferential direction.

The O-ring holding member 71 and the lid member 72, as shown in FIG.
, And is divided so that they can be overlapped with each other. The O-ring holding member 71 has a cup shape with a flange, and includes an O-ring holding recess 74 in the cup portion 71A. The lid member 72 has a flat plate shape, and the O-ring holding member 7
It is overlapped with the flange portion 71B of the O-ring holding member 71 so as to cover the first O-ring holding concave portion 74. In the O-ring holding portion 70, the concave portion 74 of the O-ring holding member 71 covered with the lid member 72 is used as an O-ring groove 75, and the O-ring 60 is loaded in the O-ring groove 75. Add friction to.

The O-ring 60 is filled in the O-ring groove 75 at a filling rate set within the range of 88-98%, preferably 90-98%, so that the O-ring 60 shown in FIG.
The temperature-friction characteristics of the hydraulic shock absorber 10 as shown in (A) to (C) can be obtained. FIG. 5 shows the measured values based on the experimental results.

(A) The hydraulic shock absorber 10 exhibits a high friction f immediately after the vehicle is started or in a slow running state. This is because the temperature of the hydraulic shock absorber 10 is on the low temperature side of about 50 ° C. or lower, and the O-ring 60 is hardly expanded inside the O-ring groove 75, but is constant under the condition that the viscosity of the hydraulic oil is high. It is considered that a high friction f is generated as a result of exerting the friction on the piston rod 13.

(B) The hydraulic shock absorber 10 exhibits a low friction f when the vehicle is in a normal running state of a race. This is because the temperature of the hydraulic shock absorber 10 rises to about 50 to 100 ° C. due to heat transfer from the engine heat during traveling, and the viscosity of the hydraulic oil decreases, so the friction f based on the friction imparting action of the O-ring 60 is low. It is supposed to become.

(C) When the vehicle is temporarily stopped during the race, the hydraulic shock absorber 10 shows a high friction f again.
This is because the temperature of the hydraulic shock absorber 10 disappears due to the air-cooling effect of the traveling wind when the vehicle is temporarily stopped, so that the temperature of the hydraulic shock absorber 10 which has increased during traveling further increases to about 100 ° C. As a result, although the viscosity of the hydraulic oil is further reduced, the hydraulic shock absorber 1
It is considered that the O-ring 60 expands under the above-mentioned filled state in the O-ring groove 75 as the temperature rises to 0, strongly presses against the piston rod 13, and the friction f based on the friction imparting action becomes higher. To be

The O-ring holding portion 70 is the hydraulic shock absorber 1.
In order to allow the O-ring 60 to have the friction characteristics as described above (A) to (C) with respect to the temperature change of 0, the filling rate of the O-ring 60 is 88 to 98%, preferably 90 to 98%. It is necessary to fill the O-ring groove 75 with a filling rate within the range. The filling rate is “O-ring cross-sectional area (π / 4 · W ² ) / groove area of the O-ring groove 75 (GH)” (W: O-ring wire diameter, G:
The groove width, H: groove depth) (FIG. 4). If the filling rate is less than 88%, the high friction f as described in (C) above cannot be obtained when the hydraulic shock absorber 10 has a high temperature. If the filling rate exceeds 98%, the friction f becomes excessive when the hydraulic shock absorber 10 is at a high temperature, and the durability of the O-ring 60 is poor.

The O-ring holder 70 has a filling rate of 88.
Since the O-ring 60 can be filled in the O-ring groove 75 at a specific filling rate selected from the range of up to 98%, preferably 90-98%, the O-ring groove 75 must have high dimensional accuracy. It is said that In the present embodiment, the O-ring holding portion 70 is configured by a combination of the O-ring holding member 71 and the lid member 72, and the O-ring holding concave portion 74 of the O-ring holding member 71 needs to be processed into a highly accurate shape and dimension. , O-ring holding recess 74
It is also necessary to perform a certain rounding process on the bottom corner portion 74A of the above so as not to scratch the O ring 60.

Further, the O-ring holding portion 70 correlates the change of the friction f due to the temperature change of the hydraulic shock absorber 10 with the change of the expansion amount of the O-ring 60.
An O-ring holding member 71 is provided with a communication passage 76 for communicating the oil with the oil chamber 12, and the O-ring expanded by the temperature rise of the hydraulic shock absorber 10.
The hydraulic oil in the ring groove 75 can be released to the oil chamber 12 side.

The O-ring holding portion 70 also uses the O-ring holding member 71 and the lid member 72 as seal retainers for the oil seal 16, so that the oil seal 16 is prevented from being impeded. The O-ring holding member 71 and the lid member 72 are provided with communication passages 77 and 78 for communicating the recess 14A with the oil chamber 12.

The friction member made of an elastic material is the O-ring 6
It does not have to be 0, but the same material as the O-ring 60 (NB
Any ring-shaped member made of R) may be used. For example, a ring-shaped member having a square cross section may be used. When the O-ring is used, a ready-made O-ring can be used, which is convenient because there is no need for cost or new design.

According to this embodiment, there are the following effects. (Operation corresponding to claim 1) Unless the influence of the hydraulic shock absorber 10 is taken into consideration, the tire temperature is on the low temperature side immediately after the start of the race or during slow running, and on the high temperature side during normal running during the race, and during the race. It is on the low temperature side again when the vehicle stops for the first time. Therefore, in order to secure a high grip force to the tire, it is necessary to raise the temperature of the tire on the low temperature side and maintain the temperature of the tire on the high temperature side so that it does not overheat. To work like.

(A) Immediately increase the tire temperature on the low temperature side immediately after starting and during slow running. At this time, the temperature of the hydraulic shock absorber 10 is still on the low temperature side of about 50 ° C. or lower, and a high friction f can be obtained by the friction imparting action of the O-ring 60 under the condition that the viscosity of the hydraulic oil is high (FIG. 5). As a result, under the action of the high friction f of the hydraulic shock absorber 10, the load received by the tire is increased to heat the tire, and the tire temperature is quickly increased.
You can secure a high grip on the tire.

(B) The tire temperature on the high temperature side during normal running is maintained so as not to overheat.
At this time, the temperature of the hydraulic shock absorber 10 rises to about 50 to 100 ° C. due to the heat transfer of the engine heat during traveling, and the viscosity of the hydraulic oil decreases, so the friction f based on the friction imparting action of the O ring 60 is low. (Fig. 5). As a result, under the action of the low friction f of the hydraulic shock absorber 10, the load on the tire is reduced to suppress further heat generation of the tire, the tire temperature is maintained so as not to overheat, and the tire has a high grip force. .

(C) At the time of primary stop during a race The temperature of the tire that has been lowered to the low temperature side is quickly increased at the time of restarting after the primary stop. At this time, the temperature of the hydraulic shock absorber 10 is further increased to about 100 ° C. or more, which has been increased during traveling, because the air cooling effect of the traveling wind accompanying the primary stop is eliminated. Although the viscosity of the hydraulic oil is further lowered, as the hydraulic shock absorber 10 rises in temperature, the O-ring 60 is replaced by the O-ring groove 75.
The piston rod 13 expands under the above-mentioned filling condition inside the piston rod 13.
The pressure f is strongly pressed against and the friction f based on the friction imparting action is increased (FIG. 5). As a result, at the time of re-traveling, under the action of the high friction f of the hydraulic shock absorber 10, the load applied to the tire is increased to heat the tire, the tire temperature is quickly raised, and a high grip force can be secured for the tire.

It is possible to easily realize the above-mentioned load / heat generation control of the tires (a) to (c) for setting the tire temperature to an appropriate high temperature state so as to secure a high gripping force on the tire. That is, without adjusting the damping force of the damping mechanism of the hydraulic shock absorber 10, the O-ring 60 is 88 to 98%, preferably 90%.
It can be realized with a simple and compact structure in which the O-ring groove 75 is filled with the filling rate within the range of up to 98%.

(Operation corresponding to claim 2) The communication passage 76 for communicating the O-ring groove 75 with the oil chamber 12 is O-shaped.
The ring holding portion 70 (O-ring holding member 71) is provided.
Therefore, when the temperature of the hydraulic shock absorber 10 becomes high, O
The hydraulic oil that expands with the expansion of the O-ring 60 in the ring groove 75 escapes from the communication passage 76 to the oil chamber 12 side, and the expanded oil amount in the O-ring groove 75 causes the above-described friction imparting action by the expansion of the O-ring 60. Can be prevented from becoming a disturbance.

(Operation corresponding to claim 3) Since the O-ring holding portion 70 is constituted by the combination of the O-ring holding member 71 and the lid member 72, the working can be facilitated and the working accuracy can be improved. That is, it is possible to obtain a highly accurate shape and dimension in the recess 74 while facilitating the processing including the bottom corner portion 74A of the recess 74 of the O-ring holding member 71. This makes it possible to easily form the O-ring groove 75 with high dimensional accuracy required to give the O-ring 60 a desired filling rate.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration of the present invention is not limited to this embodiment, and the design can be changed without departing from the gist of the present invention. Etc. are included in the present invention. For example, the O-ring holder of the present invention may be provided on the rod guide itself.

The hydraulic shock absorber of the present invention is not limited to the single tube type, but may be a double tube type in which an outer tube is provided outside the cylinder and a space between them is used as a reservoir chamber.

[0038]

As described above, according to the present invention, it is possible to obtain the friction imparting action of the hydraulic shock absorber so that the tire temperature of the vehicle can be quickly raised from the low temperature side.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a hydraulic shock absorber.

FIG. 2 is an enlarged cross-sectional view of a main part of FIG.

FIG. 3 is a cross-sectional view showing an O-ring holding member and a lid.

FIG. 4 is a schematic diagram illustrating a filling rate of an O-ring.

FIG. 5 is a diagram showing a temperature-friction relationship of the hydraulic shock absorber according to the present invention.

FIG. 6 is a diagram showing a temperature-friction relationship of a hydraulic shock absorber in a conventional example.

[Explanation of symbols]

10 hydraulic shock absorber 11 cylinders 12 oil chamber 13 Piston rod 14 Rod guide 16 oil seal 60 O-ring (friction member made of elastic material) 70 O-ring holder 71 O-ring holding member 72 Lid member 74 O-ring holding recess 75 O-ring groove 76 passage

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Jun Taruta             1-14 Fujiwara-cho, Gyoda-shi, Saitama 1 Stock             Company Showa Saitama Head Office Factory F term (reference) 3J069 AA50 AA64 CC06 CC18 CC21                       DD01

Claims (4)

[Claims] 1. A hydraulic shock absorber in which a piston rod inserted into an oil chamber provided in a cylinder is led out to the outside through a rod guide provided in an opening of the cylinder and an oil seal. A holding portion for the friction member made of an elastic material is additionally provided on the oil chamber side, and the groove provided in the holding portion for the friction member made of the elastic material is filled with the friction member made of the elastic material at a filling rate of 88 to 98%. A hydraulic shock absorber is characterized in that the friction member made of this elastic material imparts friction to the piston rod. 2. The hydraulic shock absorber according to claim 1, wherein the holding portion of the friction member made of an elastic material is provided with a communication passage that connects the groove and the oil chamber. 3. A holding member for a friction member made of an elastic material, and a holding member for the friction member made of an elastic material, which has a holding recess for the friction member made of an elastic material, and a friction member made of the elastic material. 3. The hydraulic shock absorber according to claim 1, wherein the hydraulic shock absorber is configured by a lid member that covers the concave portion of the holding member for, and the concave portion covered by the lid member is the groove. 4. The hydraulic shock absorber according to claim 1, wherein the friction member made of the elastic material is an O-ring.