JPS59151648A - Hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To make a minute vibration absorbable even in a tension stroke, by forming a chamber inside a piston rod holding a piston, while housing an inner capacity variable member, which seals a gaseous body and a liquid body inside, in this chamber. CONSTITUTION:A cylindrical chamber C is formed inside a drum member 51 of a piston rod 5 holding a piston, while an inner capacity variable member 70, which seals a gaseous body and a liquid body inside, is housed inside this chamber C. With this, when tension action is produced there, a piston 4 moves up as little as a minimal extent inside a cylinder 3 whereby oil pressure in an upper chamber S1 inside the cylinder 3 is boosted, flowing into the chamber C by way of oil passages 53 and 52 installed in the drum member 51, and the inner capacity variable member 70 is compressed so that as far as a portion for a pressure rise in oil inside the upper chamber S1 is absorbed, thus a minute vibration can be absorbed even in a tension stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a hydraulic shock absorber, and more particularly to a hydraulic shock absorber having stroke dependent characteristics on both compression and tension sides.

It consists of an outer cylinder, an inner cylinder that is installed inside the outer cylinder, and a piston rond that holds a piston that slides inside the inner cylinder. A valve mechanism that communicates with the oil chamber only during the compression stroke is attached to the lower part of the inner cylinder, and a chamber is further formed below the nozzle mechanism, and a bellows filled with gas is housed in the chamber. A pressure damper constructed by:

The so-called 3-dimensional Dan/Gu is known.

The damping force of such a damper is determined by the piston speed dependent characteristic due to the valve mechanism and the piston stroke dependent characteristic due to the bellows, and a three-dimensional characteristic is obtained, but the stroke dependent characteristic that completely absorbs minute vibrations is It is exerted only in the compression stroke, and cannot absorb even the slightest vibration in the tension stroke.

The invention was made in view of the above points, and its purpose is to provide a stroke-dependent characteristic on the tension side and to be able to absorb minute vibrations during the tension stroke. Therefore, it is an object of the present invention to provide a dual-pressure shock absorber that can exhibit stroke-dependent characteristics over both compression and bow tension.

In order to achieve such an object, the present invention provides a hydraulic shock absorber which is equipped with a damping mechanism that generates the entire damping force on a piston sliding in a cylinder, in which a chamber is formed in the piston rod and the damping force is The chamber communicates with at least an upper oil chamber of an oil chamber in the cylinder that is defined into two chambers by the piston. The gist is that a mountain passage is formed in the piston rod, and a variable internal volume member such as a bellows filled with gas is housed in the chamber of the piston rod.

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

FIG. 1 is a cutaway side view of a half part 4 of a hydraulic shock absorber according to the present invention, and FIG. 2 is a longitudinal sectional side view of the main part.

The main body of the hydraulic shock absorber 1 consists of an outer cylinder 2, an inner cylinder 3 that is a cylinder installed inside the outer cylinder, and a piston rod 5 that firmly holds a piston 4 sliding inside the inner cylinder at its lower end. Hydraulic oil is contained in each of the upper chamber S1 in the inner cylinder 3, which is divided into two chambers by the piston 4, and the reservoir chamber S3 formed between the lower chamber S2 and the inner and outer cylinders 2.3. It is enclosed.

A seal cap 6 is fitted to the upper ends of the inner and outer cylinders 2.3, and an oil passage 7 is formed in the seal cap 6 to communicate the upper chamber 81 and the reservoir chamber S3. , the downward movement of piston 4.

That is, only in the compression stroke, the lower chamber S2 and the lower chamber S
a knob mechanism 8 that communicates with 3 to generate a damping force, and
Sizing that communicates with both oil chambers S2 and 83f (not shown)
is attached.

A spring holder 9 is fixed to the upper outer periphery of the outer cylinder 2, and a coil spring 10 is stretched between the spring holder 9 and a spring holder (not shown) fixed to the upper part of the piston rod 5. There is.

The lower part of the outer cylinder 3 is connected to the shaft support of a wheel, and the upper part of the piston rod 5 is connected to a body component of a vehicle such as an automobile.

By the way, a mounting hole 41 is bored in the center of the piston 4,
A seal ring 42 is fitted on the outer periphery of the mounting hole 4.
A plurality of small holes 43... are formed radially around the periphery of 1, and a plurality of small holes 44... are similarly formed radially around the outer periphery of these small holes 43... .

The bolt 61 constituting the lower end of the piston rod 5 is inserted into the mounting hole 44 of the piston 4 from above, and at this time, the sleeve 21 is inserted between the upper surface of the piston 4 and the outer periphery of the base of the bolt 610.
is attached, and a plate ring-shaped valve 22 is loosely fitted around the outer periphery of the sleeve 21.

A coil spring 24 is compressed between the upper surface of the valve 22 and the lower end surface of the piston rod 5. The outer diameter of the valve 22 is large enough to close the outer small holes 44 of the double inner and outer small holes 43 and 44 surrounding the mounting hole 41 of the piston 4, Inner small hole 43...
Small holes 23 are formed in the surfaces of the valve 22 that correspond to the .

Furthermore, a sleeve 25 is attached to the outer periphery of the intermediate portion of the bolt 61 that protrudes downward from the piston 4, a ring-shaped pulp 26 having a hook-shaped longitudinal section is fully fitted around the outer periphery of the sleeve 25, and a plate is attached to the lower end of the sleeve 25. At this time, a coil spring 28 is compressed between the washer 27 and the lower plate washer 27 of the valve 26, and a nut 69 is fastened to the lower part of the bolt 61. The outer diameter of the valve 26 is large enough to close only the inner small holes 43, and the lower ends of the outer small holes 44 are open.

As is known, such a valve mechanism 20 provides a damping force that is dependent on the piston speed in the vertical movement of the piston 4, that is, in the compression and tension strokes of the hydraulic shock absorber 1. This can be expressed as a piston speed-damping force characteristic diagram as shown in FIG.

In FIG. 5, the characteristics when the stroke is large are shown by a solid line, and the characteristics when the stroke is small are shown by a broken line.

In the present invention, a piston stroke dependent characteristic generating device is provided within the piston rod 5, which can reduce the damping force during small strokes.

That is, a body member 51 having a diameter larger than that of the body 50 is formed between the body 50 constituting the piston rod 5 and the bolt 61 hanging from the lower end thereof, and the body member 51 is tightly attached to the lower end of the body 50. Further, a bolt 61 is similarly tightly screwed to the lower end of the body member 51.

A cylindrical chamber C that opens downward is formed in the body member 51, and an oil passage 52 is concentrically formed in communication above the chamber C. Two opposing small-diameter oil passages 53 and 53 that are open to each other are formed in communication with each other. These two small-diameter oil passages 53 and 53 produce an orisuis effect when the hydraulic oil in the upper chamber Sl flows into the chamber C in the body member 51.

On the other hand, an oil passage 63 is formed concentrically within the head 62 of the bolt 61, and a small diameter oil passage 64 is formed in communication with the lower end of the oil passage 63. An oil passage 65 having a slightly larger diameter is opened and communicated with the bolt 61 below. The lower chamber S due to the small diameter oil passage 64
An Oriais effect is obtained when the hydraulic oil in 2 flows into the chamber C in the body member 51.

A ring groove 66 is formed on the top surface of the head 62 of the bolt 61. Therefore, when connecting the bolt 61 to the lower end of the body member 51,
A metal bellows, which is the internal volume variable member 10, is housed in the chamber C of the body member 510, and a coil spring 19 is compressed into the ring groove 66 formed in the bolt head 62 to form the bellows 70.
energizes from below.

This bellows 70 is filled with gas and liquid, so that the upper part of the bellows 70 has a gas chamber G.
The lower part constitutes each liquid chamber Li, and the bellows 7
0 is in an extended state within chamber C in its free state.

The volume of the gas chamber G within the bellows 70 is approximately 1 to 3 cc. Further, guide rods 71 and 72 are concentrically protruded from the upper and lower surfaces of the bellows 70, respectively, and each guide rod 71 and 72 has an oil passage 52 formed in communication with the upper and lower sides of the chamber C,
It is in the advanced state with a gap at 63.

Next, the function of the variable internal volume member 70 will be described.

For example, when a vehicle travels on a rough road, it receives minute vibrations from the road surface, causing the hydraulic shock absorber 1 to undergo slight expansion and contraction behavior.

When tensile behavior first occurs, the piston 4 moves upward within the cylinder 3 by a minute amount, thereby increasing the pressure of the oil in the upper chamber S1 within the cylinder 3. Pressure oil flows into the chamber C through . The bellows 7 housed in the chamber C due to the inflow of this pressure oil
The gas chamber G in the upper chamber Sl is compressed, the bellows 70 is compressed, and this pressure increase of the oil in the upper chamber Sl is
It is absorbed into the gas chamber G at 0.

Also, when compression behavior occurs, all the pistons 4 in the cylinder 3 move downward slightly, and at this time, the oil in the reservoir chamber S3 passes through the oil passage 7 of the seal cap 6 and flows into the upper chamber S in the cylinder 3.
2, and as a result, the pressure of the oil in the upper chamber 82 is increased as is known, so that the pressure oil flows into the chamber C through the oil passages 53, 53 and 52 provided in the body member 51 in the same manner as described above. Inflow. The bellows 70 housed in the chamber C is thus compressed, and the increased pressure of the oil in the upper chamber Sl is absorbed into the gas chamber G of the bellows 70.

At the same time that pressure oil flows into the chamber C from the upper chamber S1 during the compression behavior, pressure oil also flows into the chamber C from the lower chamber S2.

That is, the pressure of the oil in the lower chamber S2 in the cylinder 3 is increased,
Chamber C via oil passages 65, 64 and 63 provided in bolt 61
Pressure oil flows inside. Due to the inflow of this pressure oil, the bellows 70 housed in the chamber C is compressed in the same manner as described above.
This increased pressure of the oil in both oil chambers Ss, 82 is absorbed into the gas chamber G of the bellows 70.

In the above, the knob mechanism 20 attached to the piston 4
The upper and lower valves 22 and 26 constituting the are both in a closed state.

The valves 22 and 26 are initially set to open at approximately 10 strokes of the piston 4. In addition, since a liquid chamber is formed inside the bellows 70, the liquid chamber becomes stiff when the bellows 70 is compressed.
Thus, the contractible limit of the bellows 70 is set.

On the other hand, in the case of the expansion/contraction behavior of the hydraulic shock absorber 1 in which the stroke of the piston 4 exceeds lQmm'z, the bellows 10 is in a compressed state, and the knob mechanism 20 attached to the piston 4 and the knob/rube mechanism 20 attached to the bottom of the cylinder 3 The mechanism 8 and the sizing provide a damping force with piston speed dependent characteristics.

The piston speed-damping force characteristic of the hydraulic shock absorber 1 with the above configuration is illustrated in FIG. 4.

In FIG. 4, the negative characteristic when the stroke is large is shown by a solid line, the characteristic when the stroke is medium is shown by a chain line, and the characteristic when the stroke is small is shown by a broken line.

As described above, a piston stroke dependent characteristic generating device capable of reducing the damping force on both sides of tension and compression, especially during a small stroke of the piston 4, has been constructed in the piston condo 5. However, as shown in FIG. Even if oil passages 63, 64 and 65 are not provided in 61, the hydraulic shock absorber 1
Stroke-dependent properties on both sides of tension and compression are obtained.

By the way, in the embodiment, the internal volume variable member 70 is made of a bellows, but the same effect can be obtained even if it is made of other flexible material such as a rubber bag.

As is clear from the above description, according to the present invention.

A chamber is formed within the piston rod that constitutes the hydraulic shock absorber,
An oil passage umbrella piston rond is formed which communicates the chamber with at least an upper oil chamber of an oil chamber in a cylinder which is defined into two chambers by a piston, and a gas is sealed in the chamber of the piston rond. Since the inner volume variable member is housed, stroke-dependent characteristics on the tension side can also be provided.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a partially cutaway side view of a hydraulic shock absorber, FIG. 2 is a vertical sectional side view of the same main part, and FIG. Similar figures, FIG. 4 is a piston speed-damping force characteristic diagram, and FIG. 5 is a piston speed-damping force characteristic diagram by the pulp mechanism. In the drawings, 1 is the outer cylinder of the hydraulic shock absorber 52, 3 is the cylinder, and 4 is the hydraulic shock absorber 52.
is the piston, 20 is its valve mechanism, 5 is the piston rond, 52.53 and 63.64° 65 is its oil passage, 70
is the internal volume variable member, C is the chamber in the piston rod, G is the gas chamber of the internal volume variable member, L is the same liquid chamber, Sl, 82
．． Ss is an oil chamber. 4th figure 4 head (k(])

Claims (1)

[Claims] A hydraulic shock absorber comprising a valve mechanism that generates a damping force on a piston that slides in a cylinder, wherein a chamber is formed in a piston rod that holds the piston, and gas is sealed in the chamber. An oil passage is formed in the piston rond to house the variable volume member and to communicate between at least an upper oil chamber of an oil chamber in the cylinder defined into two chambers by the piston and a chamber in the piston rond. A hydraulic shock absorber consisting of: