JPS6348834Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dust seal structure for a hydraulic shock absorber used as a rear suspension for suspending the rear body of a two-wheeled vehicle.

In this type of hydraulic shock absorber, a coil spring stretched around the outer circumference of the cylinder has one end supported by a spring holder fixed to the outer circumference of the cylinder, and the other end supported by a joint metal tied to the outer extending end of the cylinder of the piston rod. It is normal to do so.

In this case, a cylindrical spring guide 111 is provided on the joint metal side as shown in FIG. Some spring guides have a sliding structure, and the spring guide 111 serves to prevent the coil spring 115 from falling and protect the outer periphery of the piston rod 105 from flying stones and the like.

However, in such a structure,
Spring guide 111 and cylinder 1 as shown
Since there is a gap ΔC between the shock absorber and the shock absorber 02, there has been a problem in that rainwater, dust, etc. can enter the interior through the gap ΔC, and this can impair the operation of the shock absorber.

The present invention was developed to effectively eliminate such problems, and its purpose is to prevent dust from entering the shock absorber and to ensure stable operation of the shock absorber. It is to provide a dust seal structure of the buffer.

In order to achieve such an object, the present invention has a dust seal fitted to the inner periphery of the tip of a spring guide made of a rigid body that is tied to the outer extending end of the cylinder of the piston rod, and the spring guide is slid onto the outer periphery of the cylinder through the dust seal. The gist of the spring guide is that an air vent hole is formed in the circumferential wall of the tip end of the spring guide, and a shielding plate is provided in the inner circumferential wall of the spring guide opposite to the air vent hole.

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

Fig. 1 is a half-cut sectional view of a hydraulic shock absorber having a dust seal structure according to the present invention, Fig. 2 is a vertical sectional side view of a spring guide, and Fig. 3 is a view taken from the arrow 3 in Fig. 2.
FIG. 4 is a perspective view of the main parts of the spring guide.

In the front fork 1 shown in FIG. 1, 2 is a cylinder having a double cylindrical structure with inner and outer cylinders 3 and 4. A piston rod 5 is inserted into the inside of the cylinder 2 from above, and the lower end of the piston rod 5 is inserted into the cylinder 2 from above. A piston 6 is connected to the inner periphery of the inner cylinder 3 so as to be vertically slidable. And this piston 6
is provided with a valve mechanism 7 that generates a damping force.

Also, a piston rod 5 is installed on the inner circumference of the upper part of the cylinder 2.
A rod guide 8 and an oil seal 9 are fitted to slide on the outer periphery of the cylinder 2, and hydraulic oil is sealed inside the cylinder 2.

On the other hand, an upper metal 10 is screwed onto the upper end of the piston rod 5, and a cylindrical spring guide 11 made of a rigid body is fixed to the upper metal 10.
1 is the dust seal 1 fitted on the inner periphery of the tip of this
It is in sliding contact with the outer periphery of the cylinder 2 via 2, and a space S is formed inside this. Note that a stopper rubber 13 is provided below the upper metal 10 within this space S.

A coil spring 15 is stretched between the spring guide 11 and a spring receiver 14 fixed to the outer periphery of the intermediate portion of the cylinder 2, as shown in the figure.

By the way, as shown in FIGS. 2 to 4, a plurality of (three in the illustrated example) air vent holes 11a are bored in the peripheral wall of the tip end of the spring guide 11.
Further, a shielding plate 11b is integrally formed on the inner circumferential wall of the spring guide 11, facing the air vent hole 11a, and the shielding plate 11b and the dust seal 1
2 and the inner peripheral wall of the spring guide 11, a gap ΔS is formed as shown in FIG. 4, and the air vent hole 11a is formed in the gap ΔS.
is open, and notch grooves 11c, 11c bored in both side walls of the shielding plate 11b are also open.

When the piston rod 5 moves up and down with respect to the cylinder 2 due to the operation of the hydraulic shock absorber 1, the spring guide 11 moves up and down together with the piston rod 5 while slidingly contacting the outer periphery of the cylinder 2.

In this way, during the operation of the hydraulic shock absorber 1, the spring guide 11 moves up and down while slidingly contacting the outer circumference of the cylinder 2 via the dust seal 12 fitted to the inner circumference of the tip thereof, so that the space formed inside the spring guide 11 is The intrusion of dust into S is effectively prevented, so that the operation of the buffer 1 is not impaired by dust.

Incidentally, as the shock absorber 1 operates, the volume of the space S formed within the spring guide 11 increases or decreases, but in order for the shock absorber 1 to operate smoothly without resistance, the volume of the space S must be increased or decreased. As the space increases or decreases, outside air must be introduced into the space S, or internal air must be exhausted from the space S to the outside. and,
The air is supplied to the space S and the air is discharged outside the space S through the air vent holes 11a formed in the peripheral wall of the spring guide 11. Each air vent hole 1
Since the shielding plate 11b is integrally formed opposite to the spring guide 1a, the shielding plate 11b effectively prevents dust contained in the outside air or rainwater from directly entering into the spring guide 11. That is, dust, rainwater, etc. contained in the outside air collide with the shielding plate 11b and fall to the lower part of the gap ΔS, and only pure air penetrates the both side walls of the shielding plate 11b as shown by the arrows in Fig. 4. It flows into the inside of the spring guide 11 via the notched grooves 11c, 11c. Moreover, since the air vent holes 11a... and the shielding plates 11b... are integrally molded into the spring guide 11 made of a rigid body, when the shock absorber 1 expands and contracts, the relative positions of the air vent holes 11a... and the shielding plates 11b... change. It is possible to secure the function as a shielding plate without having to do so.

Further, the air vent holes 11a are provided in the peripheral wall of the tip end of the spring guide 11, and move up and down along the outer peripheral wall of the outer cylinder 4 during the extension stroke and the contraction stroke of the shock absorber 1. Therefore, during the contraction stroke of the shock absorber 1, the air in the space S flows along the outer circumferential wall of the outer cylinder 4 constituting the cylinder 2, and exchanges heat with the outer cylinder 4. The air is discharged to the outside from the air vent holes 11a. Therefore, the outer cylinder 4 is forcedly air-cooled by this air flow, so that an increase in the temperature of the differential oil sealed inside the cylinder 2 can be suppressed.

As is clear from the above description, according to the present invention, a dust seal is fitted to the inner periphery of the tip of the spring guide made of a rigid body that is tied to the outer extending end of the cylinder of the piston rod, and the spring guide is connected to the outer periphery of the cylinder via the dust seal. An air bleed hole is drilled in the peripheral wall of the tip of the spring guide, and a shielding plate is provided on the inner peripheral wall of the spring guide opposite the air bleed hole, which effectively prevents dust from entering the shock absorber. This ensures the stability of the shock absorber operation, prevents changes in the relative position of the air vent hole and the shield plate, and ensures the function of the shield plate. At this time, the air in the shock absorber is forced to flow along the outer circumferential wall of the cylinder to cool the cylinder with forced air, thereby suppressing the temperature rise of the hydraulic oil inside the cylinder.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a half-cut sectional view of a hydraulic shock absorber having a dust seal structure according to the present invention, FIG. 2 is a vertical sectional side view of a spring guide, and FIG. 4 is a perspective view of the main part of the spring guide, and FIG. 5 is a half-cut sectional view of the upper part of a hydraulic shock absorber having a conventional dust seal structure. In the drawing, 1 is a hydraulic shock absorber, 2 is a cylinder, and 5 is a hydraulic shock absorber.
is piston rod, 10 is upper metal, 11
is a spring guide, 11a is an air vent hole, 11b
11c is a shielding plate, 11c is a notched groove, 12 is a dust seal, S is a space, and ΔS is a gap.

Claims (1)

[Scope of utility model registration request] A cylinder made of a rigid body, in which a joint metal is connected to the outwardly extending end of the piston rod, which is connected to one end of a piston that slides inside the cylinder, and the joint metal receives one end of a coil spring provided on the outer periphery of the cylinder. In a hydraulic shock absorber comprising shaped spring guides connected together, a dust seal is fitted to the inner periphery of the tip of the spring guide,
A spring guide is brought into sliding contact with the outer periphery of the cylinder via the dust seal, an air vent hole is formed in the peripheral wall of the tip end of the spring guide, and a shielding plate is provided in the inner peripheral wall of the spring guide opposite to the air vent hole. The dust seal structure of the hydraulic shock absorber is characterized by: