JPH0281786A - Car height adjusting device - Google Patents

Abstract

PURPOSE:To form a pressure switch in small size by providing a pressure switch-provided pressure chamber, holding a pressure not more than a preset value when a relief valve is in operation, in a discharge side of the relief valve for a pressure increase, when car height rises, and stopping an oil hydraulic pump by action of this switch. CONSTITUTION:A down relief valve 7 and an up relief valve 8 are provided respectively between forward and return passages 4, 5 and a reservoir 1, and the valves are operated respectively at a predetermined pressure so as to return working fluid to the reservoir 1. A pressure chamber 8e is provided in a discharge side of the up relief valve 8 and a subrelief valve 10 is provided between the pressure chamber 8e and the reservoir 1, further a pressure switch 9 is connected to the pressure chamber 8e. A motor 3 is stopped when this pressure switch 9 operates. By this constitution, the pressure switch can be formed in small size.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle height adjustment device that adjusts the height of a vehicle from a road surface, and specifically, a vehicle height adjustment device that detects the completion of a vehicle height raising operation,
The present invention relates to an improvement in a method for detecting the completion of a lifting operation when, for example, a motor for driving a pump is stopped based on the detection signal.

[Conventional technology]

2. Description of the Related Art Motorcycles and four-wheeled vehicles are sometimes equipped with a vehicle height adjustment device that adjusts the height of the vehicle from the road surface in order to improve ride comfort, handling stability, and the like. This vehicle height adjustment device is, for example, as described in Japanese Patent Application Laid-Open No. 60-15211, a hydraulic passage from a hydraulic pump is connected to a hydraulic cylinder that is installed in the front and rear wheel shock absorbers. It is common to configure them by connecting them in branches. Such a vehicle height adjustment device detects the completion of the raising operation and stops the pump drive motor, and this detection means is, for example, as described in Japanese Patent Application Laid-open No. 82422/1983. Generally, a pressure switch is installed in the middle of a hydraulic passage connecting a hydraulic pump and a hydraulic cylinder.

[Problem that the invention seeks to solve]

However, in the conventional detection method described above, the set pressure of the pressure switch needs to be the rising pressure according to the normal load + the margin pressure + the pressure due to the variation in the pressure switch.
Therefore, the set pressure is considerably high. Therefore, there is a problem in that the size of the pressure switch increases and the variation in the pressure switch itself also increases.

In addition, such a hydraulic circuit must be equipped with a relief valve to prevent an abnormal rise in pressure when the pressure rises, but this relief valve must take into account the variation in the pressure switch mentioned above. It will also become larger.

The present invention has been made in order to solve the above-mentioned conventional problems, and is a vehicle height adjustment device that allows the pressure switch to have a low set pressure, thereby making it possible to downsize the pressure switch and reduce variations. is intended to provide.

[Means for solving problems]

The present invention is a device that adjusts vehicle height by supplying hydraulic oil from a hydraulic pump to a vehicle height adjustment jack cylinder, which operates with a set pressure in the hydraulic passage that is higher than the pressure when the vehicle height is raised. A pressure chamber is connected to the discharge side of the relief valve, which is maintained at a pressure equal to or lower than the set pressure when the relief valve is activated, and a pressure switch is provided in the pressure chamber, and when the pressure switch is activated, It is characterized in that the hydraulic pump is stopped.

In the present invention, maintaining the pressure chamber at a predetermined pressure can be achieved by providing a check valve type relief valve or an orifice on the outlet side of the pressure chamber.

[Effect]

In the vehicle height adjustment device according to the present invention, when the raising operation is completed, the pump discharge pressure, that is, the pressure in the hydraulic passage reaches a set pressure higher than the rising pressure, and the relief valve is activated. The pressure in the pressure chamber increases. Then, when the pressure reaches the set pressure of the pressure switch, the switch is activated, thereby detecting the completion of the raising operation and stopping the hydraulic pump.

In this way, in the present invention, the pressure switch does not directly detect the pressure in the hydraulic passage, but rather detects the pressure in the pressure chamber, so the set pressure of the pressure cassette can be lowered, and therefore the pressure switch can be adjusted accordingly. The size can be reduced, and the variation in pressure switches can be reduced accordingly.

〔Example〕

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

1 to 4 are diagrams for explaining a vehicle height adjustment device for a four-wheeled vehicle according to an embodiment of the present invention.

First, in FIG. 1 showing the hydraulic system of the device of this embodiment,
2 is a gear pump that is rotationally driven by a motor 3; 4.5 is an outbound road connected to the forward discharge port 2a and reverse discharge port 2b of the gear pump 2; and a return path;
6a and 6b are check valves. The above-mentioned outward passage 4 has a front and rear branch passage 4a.

4b, and a diverting valve 11 is disposed at the branched portion. This branch valve 11 is connected to each of the branch passages 4a.
, 4b, that is, the front and rear wheel loads, are designed to keep the hydraulic oil flow rate ratio to the jack cylinders 14a, 14b constant even if the front and rear wheel loads fluctuate.

This flow dividing valve 11 is bypassed by return passages 13a and 13b having a check valve 13C and an orifice 13d.

Further, the front and rear branch passages 4a and 4b are connected via pilot check valves 17 and 1B to front and rear jack cylinders 14a and 14b for raising and lowering the front and rear wheel portions of the vehicle. Both check valves 17 and 1B are structured to be released in the return direction at a predetermined pressure, and 5a is a biloft for supplying the pressure of the return passage 5 to the pilot check valves 17 and 18. It is a passage. Furthermore, front and rear relief valves 15a and 15b (set pressure 10
4kg/cd) is connected. Note that 16 is a relief valve for always ensuring the flow of hydraulic oil, and in this embodiment, it is set to 51 kg/-.

7 and 8 are respectively return side passages 5. These are a down relief valve and an up relief valve that are provided between the outgoing passage 4 and the reservoir 1 and return the hydraulic oil to the reservoir 1 when a predetermined pressure is reached, and in this embodiment, each has a pressure of 30 kt/aj,
It is set at 72kt/-.

Further, a pressure chamber 8e is provided on the discharge side of the up-relief valve 8.
A sub-relief valve (setting pressure 8 kg/cj) 10 is provided between the pressure chamber 8e and the reservoir 1, and a pressure switch 9 is connected to the pressure chamber 8e.

Next, the structure of the main parts will be explained in detail with reference to FIGS. 2 to 4 showing specific structural examples of the above-mentioned hydraulic system.

The reservoir 1 is attached to the upper side of the casing 20, the motor 3 is attached to the lower side, and the gear pump 2 is disposed at the lower part of the casing 20. In addition, as shown in FIG. 3, the diverter valve 11 has a valve body 21 disposed inside a casing 20 so as to be slidable in the axial direction, so as to change the passage areas a and b to the branch passages 4a and 4b. It is composed of

This valve body 21 is formed with an inflow passage 21a whose central portion communicates with the outgoing return passage 4, and both ends of the passage 21a are connected to the front, 9! Front and rear pressure chambers 21d are formed to surround both ends of the valve body 21 via the orifices 21b and 21c.
, 2L6. Note that the front orifice 21b is formed slightly larger than the rear orifice 21C. Also, front and rear pressure chambers 21d.

216 communicate with the front and rear branch passages 4a and 4b, respectively, and the passage areas a and b of these communicating portions change as the valve body 21 moves.

The pilot check valves 17 and 18 also have pistons 17 and 17 that push open the valve plates 17a and 18a, as shown in FIG.
The pilot passage 5a communicates with the portion between the pistons 17b and 18b, and when a hydraulic pressure higher than a set value acts on the passage 5a, the piston 17
b, 18b move the valve plates 17a, 18a in the opening direction,
This allows the check valve to open.

Furthermore, as shown in FIG. 4, the amplifier relief valve 8
A valve i8b for opening and closing a communication hole of the cylindrical valve seat 8a is disposed within the cylindrical valve seat 8a, and the valve i8b is pressed by a pin support 8c and a spring 8d. Further, the sub-relief valve 10 is constructed by disposing a ball 10b biased toward the hydraulic passage 4 side by a spring in a cap 10a screwed into the casing 2G. And the above pulp sea) 8a
is pressed by the cap 10a of the sub-relief 10, and both form a pressure chamber 8e.

The pressure switch 9 is mounted so that the pressure in the pressure chamber 8e acts thereon.

Next, the effects of this embodiment will be explained.

First, when the weight distribution between the front and rear wheels is as set, when the driver presses the up switch to raise the vehicle height, the motor 3 rotates in the forward direction via a control device (not shown), causing the gear pump 2 to move in the forward direction. Drive.

As a result, the pressurized hydraulic oil is diverted to each of the branch passages 4a and 4b by the diversion valve 11, and passed through the respective pilot check valves 17 and 18 to the front and rear jet cylinders 14a.
, 14b, and the vehicle height increases.

When the vehicle height reaches a predetermined height, the oil pressure suddenly increases and reaches the up-relief pressure (72 min/-), and the valve plate 8b of the up-relief valve 8 rises against the biasing force of the spring 8d. The relief valve 8 opens.

As a result, hydraulic oil flows into the pressure chamber 8e, and the pressure chamber B
The pressure in e is equal to the set pressure of sub-relief valve 10 (8 kg/
cd). This activates the pressure switch 9, and the control device stops the motor 3 in response to this activation signal, completing the vehicle height raising operation.

Next, when raising the vehicle height when the rear wheel load has significantly increased due to a full load of luggage, the internal pressure of the rear jack cylinder 14b, that is, the internal pressure of the rear branch passage 4b, will increase, and the shunt valve No. 11 valve body 21 is pushed toward the front pressure chamber 21d side, the passage area a from the front pressure chamber 21d to the front branch passage 4a is narrowed, and the pressure in the front pressure chamber 21d becomes the pressure on the rear branch passage 4b side. It will be higher to balance it. As a result, the flow rate ratio of the two portions vi and iIl paths 4a and 4b remains as originally set, and as a result, even if the load distribution changes,
The front and rear of the vehicle will rise at the same speed.

Here, as mentioned above, in this embodiment, the front orifice 21
Since the diameter of b is made slightly larger to increase the flow rate on the front side, the vehicle height adjustment on the front side is completed first.

Therefore, if left as it is, the front hydraulic pressure will rise all at once, the valve body 21 will move until it completely closes the passage from the rear pressure chamber 2tS to the rear branch passage 4b, and the rear vehicle height adjustment will stop midway. There is a concern that it will get lost.

In order to solve this problem, in this embodiment, the front branch passage 4
A front relief valve 16 is provided at a, and the pressure is set lower than the up relief pressure.

As a result, even if the front vehicle height adjustment is completed, the front branch passage 4
A flow of hydraulic oil is ensured in the rear branch passage 4b, and oil continues to be supplied to the rear branch passage 4b, allowing the vehicle to rise to a predetermined vehicle height.

Next, when the driver presses a down switch that lowers the vehicle height, the motor 3 rotates in reverse, causing the gear pump 2 to rotate in the opposite direction. Then, the pressurized hydraulic oil flows through the pilot passage 5a to the pistons 17b and 18 of the pilot check valves 17 and 18.
b, causing both pistons to move forward and close the valve plates 17a, 18.
Hold a open. As a result, the jack cylinder 1
4a.

The hydraulic oil in 14b is pushed out by the weight of the vehicle, and the pilot check valves 17, 18 . It is sucked into the gear pump 2 via the orifice 13d and the check valve 13C, and returns to the reservoir 1 via the down relief valve 7, lowering the vehicle height. Note that the control device stops the motor 3 after a predetermined timer setting time has elapsed.

In this embodiment, the pressure chamber 8e having the sub-relief valve 10 is provided on the discharge side of the up-relief valve 8, and the pressure switch 9 is connected to this, so that the rising pressure is once reduced to the sub-relief pressure. Since the pressure switch 9 is operated by this pressure, the set pressure of the pressure switch 9 can be significantly reduced to about 1/10 compared to the conventional structure that directly detects the rising pressure. Can be made smaller. Also, since the set pressure can be low,
Variations in the switch 9 itself can also be reduced. Furthermore, with the installation of the pressure switch 9 in the pressure chamber 8e, it is no longer necessary to provide the up-relief valve 8 with a margin for variations in the pressure switch, and the up-relief valve 8
can achieve miniaturization.

In addition, in this embodiment, the outgoing passage 4 and the front and rear branch passages 4a
, 4b is provided at the branch part with the flow dividing valve 11, and the load distribution is in the front,
If there is a large fluctuation in the rear wheel, the valve body 21 moves to the side with lower pressure and changes the passage area, so even if the load distribution changes, the front and rear cylinders 1
The ratio of the flow rates to 4a and 14b can be kept constant, and the front and rear vehicle heights can be adjusted simultaneously.

In the above embodiment, an example in which a flow divider valve 11 is provided has been described, but the present invention can of course be applied to a hydraulic system that does not include a flow divider valve, as shown in FIGS. 5 and 6.

In the figures, the same reference numerals as in FIGS. 1 to 4 indicate the same or corresponding parts. In this embodiment, the virofft check valve 31
．． Main relief valve 32. Only one system of check valve 33 and orifice 34 is provided.

As shown in FIG. 6, the pilot check valve 31
is configured such that a valve plate 31a biased by a spring in the closing direction can be moved in the opening direction by a piston 31b to which hydraulic pressure in the pilot passage 5a acts.

Also in this embodiment, when the vehicle height reaches a predetermined height, the up-relief valve 8 operates, and the pressure in the pressure chamber 8e increases.
The pressure switch 9 is activated, and the remoter 3 is thereby stopped.

In the above embodiment, a vehicle height adjustment device for a four-wheeled vehicle has been described, but the present invention can of course also be applied to a vehicle height adjustment device for a two-wheeled motor vehicle.

〔Effect of the invention〕

As described above, in the vehicle height adjustment device according to the present invention, a relief valve that operates at a set pressure higher than the rising pressure is connected to the hydraulic passage, and the relief valve that operates at a pressure lower than the set pressure when the relief valve operates is connected to the discharge side of the hydraulic passage. Connect the pressure chambers that are held in pressure,
By connecting a pressure switch to the pressure chamber, the completion of the rising operation is detected using the pressure that is reduced from the rising pressure, so the set pressure of the pressure switch can be reduced, which has the effect of making the pressure switch smaller. be.

[Brief explanation of the drawing]

1 to 4 are diagrams for explaining a vehicle height adjustment device according to an embodiment of the present invention, in which FIG. 1 is a hydraulic system diagram thereof, FIG. 2 is a cross-sectional side view thereof, and FIG. m-m in Figure 2
A line sectional view, Figure 4 is a line sectional view taken along line IV-IV in Figure 3, and Figure 5
6 show a modification of the above embodiment, FIG. 5 is a hydraulic system diagram thereof, and FIG. 6 is a sectional side view of the pressure switch mounting portion thereof. In the figure, 2 is a hydraulic pump, 4 is a hydraulic passage, 8 is an up-relief valve, 8e is a pressure chamber, 9 is a pressure switch, 10
1 is a sub-relief valve (pressure holding means), and 14a and 14b are jet cylinders. Patent Applicant Yamaha Motor Co., Ltd. Agent Patent Attorney Tsutomu Shimofu 2 Figure 1 3 4 Figure 6 Procedure Shiho Seishi 1)

Claims (1)

[Claims] (1) In a device that adjusts the vehicle height by supplying hydraulic oil from a hydraulic pump to the jack cylinder for vehicle height adjustment via a hydraulic passage, the hydraulic passage has a pressure higher than the pressure when the vehicle height is raised. A relief valve that operates at a set pressure is provided, a pressure chamber that is maintained at a pressure below the set pressure when the relief valve is activated is connected to the discharge side of the relief valve, a pressure switch is provided in the pressure chamber, and the pressure A vehicle height adjustment device characterized in that the hydraulic pump is stopped when a switch is activated.