JPS63159185A - Shock absorber with car height regulator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shock absorber with a vehicle height adjustment device employed, for example, in a motorcycle, and in particular, the present invention relates to a shock absorber equipped with a vehicle height adjustment device employed in, for example, a motorcycle. The present invention relates to a pressure accumulation control structure that is capable of suppressing deterioration of the shock absorbing function.

Although the present invention can be applied to any pneumatic shock absorber, a hydraulic shock absorber will be explained below as an example.

[Conventional technology]

Hydraulic shock absorbers with vehicle height adjustment devices used in motorcycles, etc. secure a predetermined vehicle height during normal driving, and adjust the vehicle height lower to make these operations easier when riding or in the military. This is a device that allows the vehicle height to be changed depending on the purpose.

Conventionally, as a shock absorber with a vehicle height adjustment device, for example, a pumping mechanism is built into a YK street appliance, which is formed by forming a pump chamber in a piston rod and inserting a plunger attached to a cylinder into the pump chamber. However, there were systems in which the high-pressure hydraulic oil generated by this pumping mechanism was pumped into the pressure accumulation chamber, and when the accumulated pressure exceeded a predetermined pressure, a relief valve was used to release the hydraulic oil to the low-pressure chamber (for example, (See Publication No. 28588).

[Problem that the invention seeks to solve]

In the above conventional device, the above-mentioned pumping mechanism is! ll Continuously performs pumping operation as the street appliance expands and contracts. In this case, the load acting on the piston rod is equivalent to the product of the generated hydraulic pressure and the cross-sectional area of the plunger during the compression stroke of the pumping operation, and disappears during the extension stroke. Furthermore, seal resistance increases to resist this oil pressure. Therefore, a large variable load acts on the piston rod compared to a shock absorber without a pumping mechanism.
This will impair the original buffering function. Even in the device equipped with the above-mentioned relief valve, since the pumping operation is always performed, it does not contribute to solving such problems.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and it is possible to shorten as much as possible the period during which load fluctuations occur on the piston rod due to pumping operation, and by extension, the period during which the buffer function is impaired, thereby improving the overall riding comfort of the piston rod. The purpose of the present invention is to provide a shock absorber with a vehicle height adjustment device that can improve the vehicle feel.

[Means for solving problems]

The present invention incorporates a pumping mechanism consisting of a pump chamber formed in a piston rod and a plunger attached to a cylinder, and uses this mechanism to accumulate high-pressure working fluid in a pressure accumulation chamber, and uses the accumulated pressure to adjust the vehicle height. In a shock absorber with a vehicle height adjustment device, when the accumulated pressure is below a predetermined value, only the flow from the operating chamber to the pump chamber is allowed in the passage that communicates the operating chamber and the pump chamber, and when the accumulated pressure is below a predetermined value, the flow is allowed to flow from the operating chamber to the pump chamber. In this case, a pressure accumulation control valve is installed to allow flow in both directions.

[Effect]

According to the shock absorber with a vehicle height adjustment device according to the present invention, when the pressure in the pressure accumulation chamber is below a predetermined value, that is, mainly at the start of traveling, the shock absorber is activated during the extension stroke, as in the conventional shock absorber. Fluid is drawn from the working chamber into the pump chamber through the pressure accumulation control valve, is pressurized during the contraction stroke, and is accumulated in the pressure accumulation chamber. On the other hand, when the pressure in the pressure accumulation chamber exceeds a predetermined value, the pressure accumulation control valve flows in both directions between the working chamber and the pump chamber, and as a result, the working fluid sucked into the pump chamber during the extension stroke flows directly into the working chamber during the contraction stroke. ie the pumping action is canceled. Therefore, in the present invention, after the accumulated pressure reaches a predetermined value or more, the load fluctuation on the piston rod is completely eliminated, the period during which the buffer function is activated is significantly shortened, and the overall riding feeling is greatly improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 5 are diagrams for explaining one embodiment of the present invention. First, we will begin with the fifth section showing the schematic configuration of the device of this embodiment.
In the figure, 2 is a shock absorber, and its lift chamber 13, pump chamber 112 and working chamber 3 are communicated through a main passage 25 and second and second hydraulic passages 14 and 15 branched from this, respectively. A pressure accumulation chamber 17 is connected to the hydraulic passage 14 . Further, the working chamber 3 and the pump chamber 11 are communicated through a third hydraulic passage 16. A hydraulic control device 18 is disposed at a branch portion between the main passage 25 and the second and second hydraulic passages 14.15.

The third hydraulic passage 16 is provided with an unload valve 23 for canceling the pumping action when the accumulated pressure exceeds a specified value.
As will be described later, this embodiment is characterized by the structure of the unload valve 23.

In addition, 1O is a sub tank for replenishing hydraulic oil, 21
a and 21b are check valves for accumulating pressure and for raising vehicle height, respectively;
22a and 22b are throttle valves for adjusting vehicle height raising and lowering speed;
Reference numeral 4 designates a safety relief valve in case the unload valve 23 fails.

Next, in FIGS. 2 to 4 showing a concrete structure of the shock absorber 2, the cylinder 1 of the shock absorber 2 has a vehicle body support portion 1a fixed to the upper end of a cylindrical member, and the lower end is closed with an end plate 1b. It will be done. A lift case 6 constituting the lift chamber 13 is slidably mounted on the cylinder 1, and the lift case 6 is formed with a first spring receiver 6a for locking a buffer spring to be described later. A piston rod 5 having a piston 9 at its upper end is slidably inserted into the cylinder 1, and a vehicle body support section 4 is disposed at the lower end of the piston rod 5, and a second spring receiver is disposed above this. 7 is firmly formed. A buffer spring 8 is interposed between the second spring receiver 7 and the first spring receiver 6a. This buffer spring 8 is a two-stage spring consisting of a main spring 8a and an auxiliary spring 8b, and a movable spring receiver 19 is interposed between the two springs 8a and 8b. It is slidably attached to the

The unload valve 23 is formed in the vehicle body support portion 1a. As shown in a conceptual diagram in FIG. 1, this unload valve 23 is composed of a tilt type control valve 26 and a valve body driving section 27 that drives the tilt type control valve 26. The tilt type control valve 26 has a valve chamber 16b having an opening/closing hole 16a formed in the middle of the third hydraulic passage 1R16 that communicates the working chamber 3 and the pump chamber 11, and a tilt type valve body 28 in the valve chamber 16b.
It is configured by arranging. Valve shaft 28a of this valve body 28
protrudes from the opening/closing hole 16a toward the working chamber 3, and its valve plate 28b is pressed against the opening/closing hole edge 16C by a biasing spring 28C. Note that 29a and 29b are plug members.

Further, the valve body drive section 27 is configured such that a drive pin 31 is disposed in a drive chamber 30 communicating with the pressure accumulation chamber 17 so as to be movable in the axial direction. This drive pin 31 penetrates the bottom of the drive chamber 30 and can press the valve shaft 28a of the valve body 28, and the drive pin 31 is pushed toward the pressure accumulation chamber side by a biasing spring 32, that is, the valve shaft. It is biased in the direction away from 28a. The biasing spring 32 is set to have a biasing force that causes the drive pin 31 to tilt the valve shaft 28a when the pressure in the pressure storage chamber 17 exceeds a specified pressure.

Next, the effects of this embodiment will be explained.

In the device of this embodiment, when the pressure in the pressure accumulation chamber 17 is low, such as at the start of travel, the drive pin 31 of the unload valve 23 is pushed by the biasing spring 32 and is located at its backward end, and the valve body 28 is It is in a standing position. Therefore, the third hydraulic passage 16 is connected from the working chamber 3 to the pump chamber 1 by the check valve function of the valve body 28.
Distribution is now possible in only one direction. Therefore, as the shock absorber 2 expands and contracts, when the pressure in the pump chamber 11 becomes lower than that in the working chamber 3 during the expansion stroke, the hydraulic oil flows into the unload valve 2.
The valve body 28 of No. 3 is pushed open to be sucked into the pump chamber 11. This hydraulic oil is pressurized during the contraction stroke and is forced into the pressure accumulation chamber 17 through the pressure accumulation check valve 21a.

When the pressure in the pressure storage chamber 17 rises above a specified value due to the pressure-fed hydraulic oil, the drive pin 31 moves forward due to this pressure, and its tip pushes the valve body 28 of the unload valve 23 to tilt it. As a result, the third hydraulic passage 16 becomes a conductive layer not only from the working chamber 3 to the pump chamber 11 but also in the opposite direction, so that from now on, from the working chamber 3 to the pump chamber 11 in the extension stroke. The sucked hydraulic oil returns to the working chamber 3 without being pressurized during the contraction stroke,
In other words, the pumping operation will be canceled.

Next, when the driver switches the vehicle height changeover switch to the upward side, the pressure control device 18 causes the pressure accumulation chamber 17 and the lift chamber 13 to communicate with each other. This compresses the auxiliary spring 8b, bringing the lift case 6 into contact with the movable spring receiver 19, increasing the set load and spring constant of the buffer spring 8, decreasing the sinkage meter, and raising the vehicle height. Then, when the pressure in the pressure accumulation chamber 17 decreases, the drive pin 31 retreats and the valve body 28 becomes erect, the pumping operation is restored and the hydraulic oil is force-fed to the pressure accumulation chamber 17. When the pressure reaches the specified pressure, the pumping operation is resumed. canceled out.

In this way, in the device of this embodiment, after the pressure inside the pressure accumulator 17 reaches the specified pressure, the unload valve 23 maintains conduction between the working chamber 3 and the pump chamber 11 in both directions. When sufficient hydraulic oil is accumulated in the pump 17, the pump operation can be canceled. In other words, during normal driving after hydraulic oil has been stored, it will operate in the same way as a shock absorber without a vehicle height adjustment device, and the adverse effect on the shock absorbing function due to the pumping operation will depend on the start of driving, etc. It only takes a short time, and the overall riding feeling can be improved.

In addition, since the unload valve 23 employs a tilt type structure as the structure that allows conduction in both directions, only a small amount of driving force is required for the unload valve 23, and the operation can be performed reliably.

In the above embodiment, a tilt type valve structure is adopted for the unload valve 23, but various modifications can be considered to the structure of the unload valve 23, and the structure is not limited to the above tilt type valve structure. In short, the present invention may be configured such that the working chamber and the pump chamber are electrically connected in both directions when the accumulated pressure is equal to or higher than a specified value.

〔Effect of the invention〕

As described above, according to the shock absorber with a vehicle height adjustment device according to the present invention, the working chamber and the pump chamber are connected only in the direction from the working chamber to the pump chamber when the pressure in the accumulator chamber is below the specified value, and when the pressure in the accumulator chamber is below the specified value, Since conduction is established in both directions, the pumping action can be canceled after the necessary working fluid has been stored in the pressure accumulator, eliminating unnecessary pumping action, ensuring a high buffering function, and improving riding comfort. There is an effect that can be done.

[Brief explanation of the drawing]

Figures 1 to 5 show vehicle height according to an embodiment of the present invention! I
f! Figure 1 is a conceptual diagram of the unloading valve, Figure 2 is a sectional plan view of the unloading valve and the unloading valve, and Figure 3 is a sectional side view thereof. FIG. 4 is a sectional side view of a shock absorber employing the above-mentioned unload valve, and FIG. 5 is a system diagram showing the overall structure of the above-mentioned shock absorber. In the figure, ■ is the cylinder, 2 is the shock absorber, 3 is the working chamber,
5 is a piston rod, 11 is a pump chamber, 12 is a plunger, 16 is a third hydraulic passage (passage), 16a is an opening/closing hole, 1
6b is a valve chamber, 16e is an opening/closing hole edge, 17 is a pressure accumulation chamber, 23
2 is an unload valve (N pressure control valve), 26 is a tilt 2 control valve, 27 is a valve body drive unit, 28 is a valve body, 28a is a valve shaft, 28
b is the valve plate, 30 is the drive chamber, 31 is the drive pin (drive member)
It is. Patent Applicant Yamaha Motor Co., Ltd. Agent Patent Attorney Tsutomu Tsutomu Figure 1 Figure 2 Figure 3 Figure 5

Claims (2)

[Claims] (1) A pumping mechanism formed by inserting a plunger attached to a working chamber of a cylinder into a pump chamber formed in a piston rod is built-in, and working fluid pressurized by the pumping mechanism is stored in a pressure accumulation chamber, In a shock absorber with a vehicle height adjustment device that uses the pressure of the working fluid to adjust the vehicle height, a passage communicating between the working chamber and the pump chamber is provided with a passage that communicates with the working chamber when the pressure in the pressure accumulator is below a predetermined pressure. A shock absorber with a vehicle height adjustment device characterized by interposing a pressure accumulation control valve that allows flow only in the direction of the pump chamber from the pump chamber, and allows flow in both directions between the working chamber and the pump chamber when the pressure is higher than a predetermined pressure. Device. (2) The pressure accumulation control valve is composed of a tilt type control valve that opens and closes a passage by tilting the valve shaft in a direction perpendicular to the axis, and a valve body drive unit that tilts and drives the control valve, and the tilt type control valve The valve forms a valve chamber having an opening/closing hole in the passage, a valve body is placed in the valve chamber, the valve shaft thereof protrudes through the opening/closing hole toward the working chamber, and the valve plate is attached to the edge of the opening/closing hole. The valve body drive section is configured to be biased so as to come into contact with the
A drive chamber is formed that communicates with the pressure accumulation chamber, and the drive member is movable in the axial direction so that the tip of the drive member passes through the bottom of the drive chamber and faces the valve shaft in the valve chamber. 2. A shock absorber with a vehicle height adjustment device according to claim 1, characterized in that the drive member is biased in a direction against pressure accumulation.