JPS6243157Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rod guide mechanism in a hydraulic shock absorber used in automobiles and the like.

Generally, in this type of hydraulic shock absorber, the first
As shown in the figure, pressurized gas is sealed between a guide housing 2 disposed at one end 1a of a cylinder 1 filled with hydraulic fluid and the cylinder 1, surrounding the cylinder 1. A seal housing 5 disposed within one end 4a of the outer cylinder 4 forming the liquid reservoir chamber 3; and a slidable piston rod 6 extending into the cylinder 1 through the guide housing 2 and the seal housing 5. A piston 10 is provided with a damping force generating mechanism 9 fixed to the end 6a of the piston rod 6 to separate the inside of the cylinder 1 into two chambers, an upper liquid chamber 7 and a lower liquid chamber 8.
A dust seal member 11 and a liquid seal member 12 are provided at both ends of the seal housing 5 in the axial direction and are in sliding contact with the outer peripheral surface of the piston rod 6. Note that 14 is a communication hole in the bottom body 13 provided at the bottom of the cylinder 1 that communicates the reservoir chamber 3 and the lower liquid chamber 8, and 15 is a cylindrical hole fixed to the part of the guide housing 2 facing the piston rod 6. The bushing 16 allows the hydraulic fluid to flow into the reservoir chamber 3 from the seal chamber 17 formed between the liquid seal member 12 and the guide housing 2, but conversely allows the hydraulic fluid to flow into the seal chamber 17 from the reservoir chamber 3. A one-way valve 18 made of rubber or the like that prevents the inflow of pressurized gas is a mounting ring fixed to the end of the outer cylinder 4 and rotatable with respect to the axle 19.

The hydraulic shock absorber having such a configuration operates as follows.

(1) In the case of extension stroke of the piston rod 6 When the piston rod 6 rises, the piston 10 that follows it causes the upper liquid chamber 7 to have a high pressure, and conversely, the lower liquid chamber 8 to have a low pressure. At this time, the high-pressure hydraulic fluid in the upper fluid chamber 7 passes through the through hole 9a that constitutes the damping force generation mechanism 9 provided in the piston 10, pushes open the plate valve 9b provided at the outlet end of the through hole 9a, and opens the orifice. When the liquid passes through the orifice at high speed, the static pressure is changed to dynamic pressure, the pressure drops, and the liquid flows into the lower liquid chamber 8. Thus, the piston 10 is urged downward by the pressure in the upper liquid chamber 7, generating an extension-side damping force that attempts to prevent the extension stroke. At the same time, the hydraulic fluid generated when a part of the piston rod 6 exits from the cylinder 1 is transferred from the reservoir chamber 3 into the lower liquid chamber 8 through the communication hole 14 provided at the bottom of the cylinder 1. will be compensated for. On the other hand, a part of the working fluid in the upper fluid chamber 7 flows into the seal chamber 17 through the gap _C1 between the piston rod 6 and the cylindrical bushing 15, as shown in FIG. It effectively lubricates the sealing member 12, and furthermore, it flows into the passage 20 formed between the seal housing 5 and the guide housing 2 and makes a predetermined contact with the sealing surface 2a formed on the outer periphery of the guide housing 2. The lip portion 16a of the one-way valve 16 that is in elastic contact with pressure is pushed open, a plurality of notches are provided on the outer periphery of the guide housing 2, and the passage _C2 formed between these and the outer cylinder 4 is passed through. ,
It is refluxed into the reservoir chamber 3.

(2) In the case of the pressure stroke of the piston rod 6 When the piston rod 6 descends, the lower liquid chamber 8 becomes high pressure due to the piston 10 moving therewith, and conversely, the upper liquid chamber 7 becomes low pressure.
The working fluid in the lower fluid chamber 8 passes through the through hole 9c constituting the damping force generating mechanism 9, pushes open the plate valve 9d provided at the outlet end thereof to form an orifice, and passes through the orifice at high speed. When the static pressure is changed to dynamic pressure and the pressure drops, the upper liquid chamber 7
flows within. Thus, the piston 10 is urged upward by the pressure in the lower liquid chamber 8, generating a compression-side damping force that attempts to prevent the compression stroke.
On the other hand, a part of the piston rod 10 is attached to the cylinder 1.
The hydraulic fluid generated when the piston rod intrudes into the reservoir chamber 3 returns from the lower fluid chamber 8 to the reservoir chamber 3 through the communication hole 14 at the bottom, and returns to the reservoir chamber 3, which is sealed at a predetermined pressure inside the reservoir chamber 3. Further compresses the pressurized gas. At this time, the lip portion 16a of the one-way valve 16 is connected to the guide housing 2 and the outer cylinder 4.
The sealing surface 2a of the guide housing ₂ is pressed by the pressure of the pressurized gas acting through the passage C2 between the two and the tension force of the one-way valve 16 itself, as shown in FIG. As said passage 20
is completely closed to effectively prevent pressurized gas from flowing into the upper liquid chamber 7.

Incidentally, in a hydraulic shock absorber having such a configuration, although the cylinder 1 is filled with clean hydraulic fluid that is free of foreign matter, when the vehicle is running, etc. The cylinder 1, the guide housing 2, the piston 10, or the seal may be damaged due to the wear particles generated due to the sliding friction between the cylinder 1 and the piston 10, which slide against each other while receiving a load in the direction, or due to the high-speed flow of the hydraulic fluid. Foreign objects such as burrs that have fallen off from the edges of the housing 5 etc. may get mixed into the clean working fluid, and such foreign objects may damage the cylindrical bush 15 and piston rod 6 that are fitted into the guide housing 2. In some cases, the hydraulic fluid entered the clearance _C1 between the hydraulic fluid and the hydraulic fluid. When such a situation occurs, one end of the piston rod 6 is fixed to the vehicle body side, while the ends of the outer cylinder 4 and cylinder 1 are fixed to the axle side.
Bending force is applied to the piston rod 6 due to lateral loads when the vehicle is running, and the piston rod 6 is constantly pressed against the guide housing 2. Therefore, foreign matter such as metal powder that has entered the clearance _C1 may cause the piston rod 6 to bend. As the liquid seal member 12 slides, its outer circumferential surface is damaged, and the liquid seal member 12 is damaged, causing problems such as leakage of hydraulic fluid or sealed gas.

The piston rod 6 is slidably supported at two locations: a piston 10 that is slidably inserted into the cylinder 1, and a cylindrical bush 15 that is fixed to the guide housing 2. In the case of a pressure buffer, the cylindrical bush 15
is the piston 10 below the liquid seal member 12
Since it is provided in the guide housing 2 located closer to the guide housing 2, the distance between the fulcrums between the piston 10 and the cylindrical bush 15 for supporting the piston rod 6 is short (especially when the piston rod 6 is in the fully extended state). , the distance between the supporting points becomes significantly shorter). Therefore, when a lateral load is applied while the vehicle is running, the maximum gap between the piston rod 6 and the cylindrical bush 15 becomes larger, making it even more likely that foreign objects will become trapped. Furthermore, the reaction force against the lateral load at both the fulcrums of the piston 10 and the cylindrical bush 15 becomes large, making it easy for wear to occur as the piston rod 6 slides.

In view of these conventional drawbacks, the present invention prevents damage to the outer circumferential surface of the piston rod due to foreign matter mixed into the cylinder, and prevents leakage of hydraulic fluid or sealed gas. , ensure a sufficiently long distance between the fulcrums that support the piston rod, and allow the piston rod to extend and
The purpose of this invention is to propose a rod guide mechanism for a hydraulic shock absorber that can perform compression smoothly without uneven wear.

An embodiment of the present invention will be described below with reference to the drawings. Note that parts that are the same as those in the configuration of the conventional example are given the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 3 is a sectional view of essential parts showing an embodiment of the rod guide mechanism in the hydraulic shock absorber according to the present invention.

As shown in FIG. 3, the guide housing 2 has an annular recess 2 at a portion facing the piston rod 6.
1 is formed, and the annular guide member 22 is placed in this annular recess with a required clearance C ₄ between it and the piston rod 6 and a predetermined clearance C ₃ between it and the inner periphery of the annular recess 21. It is inserted. That is, the guide member 22 does not guide and support the piston rod 6, but is housed in the annular recess 21 so as to be movable in the radial direction, and prevents the circulation of the hydraulic fluid for lubricating the liquid seal member 12. However, since the piston rod 6 moves in the radial direction against eccentricity, falling, bending, etc. caused by the lateral load of the piston rod 6, foreign matter mixed in the cylinder 1 is prevented along with the hydraulic fluid. Even when the foreign matter enters the clearance _C4 between the guide member 22 and the piston rod 6, the foreign matter is not strongly compressed, and therefore the outer peripheral surface of the piston rod 6 is not damaged by the foreign matter. In this embodiment, this guide member 22 is
Although it is formed of two members: a hard member 23 and a low-friction material (for example, a fluorine resin material, a sintered material, etc.) 24 fixed to the inside thereof, the whole may be formed of a low-friction material.

The seal ring member 25 disposed within the annular recess 21 is for liquid-tightly sealing between the guide member 22 and the guide housing 2, and the stopper ring 26 fixed to the guide housing 2 is for This is to prevent the guide member 22 from coming off in the axial direction.

On the other hand, a bush 27 is press-fitted into the seal housing 5 having the dust seal member 11 and the liquid seal member 12 to receive the bending force acting in the radial direction of the piston rod 6, and preferably to smooth the insertion and removal movement of the piston rod 6. A guide portion 5a is provided. This guide portion 5a is
It is provided on the seal housing 5 side above the liquid seal member 12, and is designed to ensure a sufficiently long distance between supporting points that support the piston rod 6 together with the piston 10.

In this way, in this embodiment, the guide member 22 functions to circulate the hydraulic fluid for seal lubrication.
is fitted on its outer periphery within the annular recess 21 so as to create a predetermined clearance _C3 , so that the piston rod 6 can easily move in response to radial movement of the piston rod 6 due to a lateral load. Even if foreign matter mixed into the cylinder 1 enters the clearance _C4 between the guide member 22 and the piston rod 6 together with the hydraulic fluid, the foreign matter will not be caught between the piston rod 6 and the piston rod 6. Therefore, the outer circumferential surface of the piston rod 6 is not damaged by foreign matter, and of course damage to the liquid sealing member 12 is also avoided, and a situation in which the hydraulic fluid or the sealed gas leaks can be prevented.

Furthermore, in this embodiment, the guide portion 5a that supports the piston rod 6 in cooperation with the piston 10 is provided on the inner peripheral portion of the seal housing 5 facing the piston rod 6, so that the piston 10 and the guide portion 5a are The distance between the piston rod fulcrums can be made sufficiently long, and therefore the reaction force of these two fulcrums can be reduced. Therefore, abnormal friction occurs between the cylinder 1 and the piston 10 and between the piston rod 6 and the bush 27.
It is possible to prevent uneven friction from occurring.

In the embodiment shown in FIG. 3, the annular recess 21
is formed on the seal housing 5 side of the guide housing 2, and the guide member 22 is fitted into the seal housing 5 side with a gap in the radial direction. It may be formed on the upper liquid chamber 7 side, and the guide member may be fitted into the interior thereof with a clearance in the radial direction.

As is clear from the above description, the present invention forms an annular recess in the portion of the guide housing that faces the piston rod, and within the annular recess, the necessary distance between the piston rod and the inner periphery of the annular recess is provided. An annular guide member is inserted with a clearance of
Even if foreign matter mixed in the cylinder enters the clearance between the guide member and the piston rod together with the hydraulic fluid, the foreign matter will not be caught between the piston rod. Therefore, the outer peripheral surface of the piston rod is not damaged by foreign matter, so damage to the liquid sealing member is also avoided, and a situation in which the hydraulic fluid or the sealed gas leaks can be prevented.

In addition, the present invention provides a guide part that cooperates with the piston and supports the piston rod in the seal housing, which is disposed further away from the guide housing when viewed from the piston, and has a longer guide part than in the conventional example. Since the piston rod is supported by the distance between the fulcrums, the reaction force at the fulcrum can be reduced, which prevents abnormal friction or uneven friction between the cylinder and the piston, and between the piston rod and the bushing. can be prevented from occurring. Therefore, smooth piston action can be performed.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted vertical sectional view showing a conventional hydraulic shock absorber, Fig. 2 is an enlarged sectional view showing the surroundings of the guide housing, seal housing, etc., and Fig. 3 is a rod guide in the hydraulic shock absorber of the present invention. FIG. 3 is an enlarged cross-sectional view of a main part showing the mechanism. 1... Cylinder, 1a... One end, 2... Guide housing, 3... Reservoir chamber, 4... Outer cylinder, 4
a... One end, 5... Seal housing, 5a...
Guide portion, 6... Piston rod, 7... Upper liquid chamber, 8... Lower liquid chamber, 9... Damping force generation mechanism, 1
0... Piston, 11... Dust seal member, 1
2... Liquid sealing member, 21... Annular recess, 22
...Guide member, 27...butsuyu.

Claims (1)

[Scope of utility model registration request] Hydraulic liquid is filled between the guide housing, which is disposed at one end of a cylinder whose inside is filled with hydraulic fluid, and the cylinder, surrounding the cylinder, and the hydraulic fluid is filled under pressure with sealed gas, and the bottom of the cylinder is filled with hydraulic fluid. a seal housing disposed above the guide housing within one end of the outer cylinder and forming a reservoir chamber communicating with the interior; and a sliding member extending into the cylinder through the guide housing and the seal housing. a piston rod fixed to the end of the piston rod to separate the inside of the cylinder into two chambers, an upper liquid chamber and a lower liquid chamber, and a piston having a damping force generating mechanism; A hydraulic shock absorber including a dust seal member and a liquid seal member, which are respectively disposed at both ends and are in sliding contact with the outer circumferential surface of the piston rod, and an annular recess is provided in a portion of the guide housing facing the piston rod. An annular guide member is fitted into this annular recess with a required clearance between the piston rod and the inner periphery of the annular recess, and a radius of the piston rod is inserted into the seal housing. A rod guide mechanism in a hydraulic shock absorber, which is provided with a guide section that receives a bending force acting in a direction.