JPH064444U - Piston rod guide mechanism of vehicle shock absorber - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Even if there is axial misalignment between the piston rod and the guide bush, it prevents one-sided contact at the end of the guide bush and reduces the damping force of the shock absorber. Stabilize. [Structure] A rod guide 13 for supporting a piston rod 12 in a cylinder 11 and an inner peripheral sliding surface of a guide bush 15 mounted in a housing 14 of the rod guide have a central portion in the axial direction swelling and the piston rod 12 In the guide bush 15 that comes into contact with the outer peripheral surface, grooves 17 are provided at both outer peripheral ends of this guide bush.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a piston rod guide mechanism for a vehicle, especially a shock absorber of an automobile.

[0002]

[Prior art]

 Shock absorbers reduce the vibration of automobiles to improve the ride comfort of passengers, protect the load, and increase the life by reducing the dynamic stress of each part of the vehicle body, and enhance the ground contact of tires to improve maneuverability and stability. It improves the property and reduces the impact on rough roads. There are a cylinder type and a lever type in such a vehicle shock absorber, but the cylinder type is currently mainly used because it is lighter and cheaper than the lever type.

An example of this cylindrical structure is disclosed in Japanese Patent Laid-Open No. 58-28033. That is, in FIG. 3, 11 is a shock absorber cylinder, 12 is a piston rod installed in the cylinder 11, and is supported by a rod guide 13 fixed to the upper end of the cylinder 11 so as to be capable of reciprocating sliding movement. Reference numeral 15 is a guide bush mounted in the housing 14 of the rod guide 13 and having polytetrafluoroethylene (PTFE) resin adhered to the inner peripheral surface of the backing metal 15a. The inner peripheral sliding surface 16 has a center in the axial direction. The part has a bulge and its cross-sectional shape is an arc shape. The sliding surface 16 is formed so that even when the piston rod 12 slides with respect to the guide bush 15, it can always contact the outer peripheral surface of the piston rod 12 via an oil film. In the shock absorber configured as described above, even if the piston rod 12 swings with respect to the guide bush 15 and the shaft center is deviated, a partial contact between the outer peripheral surface of the piston rod 12 and the end portion of the guide bush 15 is generated. In addition, a wedge shape is formed between the inner peripheral sliding surface 16 and the piston rod 12, and an oil film is easily formed due to this wedge effect, so the advantage that the lubrication state is good is recognized. However, it is not enough.

[0004]

[Problems to be solved by the device]

 The present invention aims to solve the above-mentioned problems. Specifically, by devising the shape of the circumferential surface of the guide bush, the lubrication between the two is further improved and the piston rod is smoothed. The purpose is to propose a piston rod guide mechanism that can be operated in a stable manner to stabilize the damping force of the shock absorber.

[0005]

[Means for Solving the Problems]

 That is, the present invention is provided with a rod guide for slidably mounting a piston rod in a cylinder of a vehicle shock absorber, and a guide bush mounted in the housing of the rod guide causes an inner circumference due to an eccentric load. It is characterized in that grooves are provided at both outer peripheral ends of the guide bush so that the sliding surface has a bulge at the center in the axial direction.

Hereinafter, the configuration and the operation of the device of the present invention will be described in detail.

The inventors of the present invention have conducted research and development on a guide bush that can easily follow the guide bush even if the piston rod bends. As a result, a groove (thin portion) is formed at both ends of the outer peripheral surface of the guide bush. We have obtained the knowledge that it is possible to follow the deflection of the piston rod. As a result of further research, this proposal was approved.

The present invention will be described below with reference to the drawings.

FIG. 1 is a shock absorber according to one embodiment of the present invention. FIG. 1 is a longitudinal sectional view showing a guide mechanism for a piston rod in which the guide bush is deformed into an arc shape by an unbalanced load according to the present invention. 2 is a perspective view of the guide bush used in FIG. 1, FIG. 3 is a vertical cross-sectional view of a piston rod guide mechanism of a conventional shock absorber, and FIG. 4 is a guide used in FIG. It is a perspective view of a bush. Reference numeral 11 is a cylinder, 12 is a piston rod, 13 is a rod guide, 14 is a housing, 15 is a guide bush, 15a is a back metal, 16 is an inner peripheral sliding surface, and 17 is a groove (thin portion).

First, as shown in FIG. 1, reference numeral 11 is a shock absorber cylinder, and 12 is a piston rod installed in the cylinder 11, which is reciprocally slidable by a rod guide 13 fixed to the upper end of the cylinder 11. It is supported. Reference numeral 15 is mounted in the housing 14 of the rod guide 13, and the backing metal 15a is a guide bush having PTFE resin adhered to its inner peripheral surface, and its inner peripheral sliding surface 16 has a central portion in the axial center direction due to one-sided unbalanced load. It improves the rod guide 13 so that it bulges inward about 10 to 100 μm and has an arcuate cross-sectional shape. The sliding surface 16 is always the same even when the piston rod 12 swings with respect to the guide bush 15. The rod 12 is formed so as to come into contact with the outer peripheral surface of the rod 12 via an oil film. If grooves (thin portions) 17 are provided at both ends of the outer peripheral surface of the guide bush 15, the grooves (thin portion) 17 at both ends are The piston rod 12 follows the deflection of the axis of the piston rod and is elastically deformed to prevent the piston rod 12 and the guide bush 15 from hitting each other at one end. By improving the lubricity state Sum the operation of the piston rod 12 - is in the figure, shock absorber - the damping force of the bar can be stabilized.

Further, the sliding surface 16 may be formed by adding a circumferential groove taper or the like as shown in the conventional example.

[0012]

[Effect of device]

 As described above in detail, according to the present invention, a rod guide for supporting a piston rod slidably installed in a cylinder of a shock absorber for a vehicle is provided, and a guide bush mounted in the housing of the rod guide is provided with an eccentric load. Thus, grooves are provided at both outer peripheral ends of the guide bush so that the inner peripheral sliding surface has a bulge at the central portion in the axial direction.

According to the present invention, since the grooves (thin portions) are provided at both ends of the outer peripheral surface of the guide bush of the shock absorber, the flexure of the shaft of the piston rod 12 is followed and the elastic deformation occurs. Even if there is a shaft misalignment between the piston rod and the guide bush, the guide bush is prevented from abutting against each other, the lubrication condition between them is good, and the piston rod operates smoothly, resulting in shock absorption. The damping force of the bar can be stabilized.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a guide mechanism for a piston rod of a shock absorber according to an embodiment of the present invention.

FIG. 2 is a perspective view of a guide bush used in FIG.

FIG. 3 is a vertical cross-sectional view of a piston rod guide mechanism of a conventional shock absorber.

FIG. 4 is a perspective view of a guide bush used in FIG.

[Explanation of symbols]

 11 Cylinder 12 Piston Rod 13 Rod Guide 14 Housing 15 Guide Bushing 15a Back Metal 16 Inner Sliding Surface 17 Groove (Thin-walled part)

Claims (1)

[Scope of utility model registration request] 1. A rod guide for supporting a piston rod slidably mounted in a cylinder of a shock absorber for a vehicle is provided, and a guide bush mounted in a housing of the rod guide is slid on an inner circumference by an eccentric load. A piston rod guide mechanism for a shock absorber for a vehicle, characterized in that grooves are provided at both outer peripheral ends of a guide bush so as to have a bulge at a central portion in the axial direction of the surface.