JPS6296110A - Ground clearance adjuster for automobile - Google Patents

Abstract

PURPOSE:To prevent working oil from being increased in its pressure abruptly in a ground clearance adjuster where NO.1 change-over valve is opened with NO.2 change-over valve closed so as to increase the ground clearance by providing a means which allows the closing time of NO.2 chang-over valve to be delayed from the opening time of NO.1 change-over valve. CONSTITUTION:In this ground clearance adjuster, the ground clearance is adjusted in such a way that a control unit makes opening/closing of levelling valves 16, 19, and 33 and an unloader valve 38 upon receiving the signals sent from ground clearance sensors. In case of a n upward adjustment, the unloader valve 38 is closed while being delayed by a specified period of time after the levelling valves 16, 29, and 33 are opened for feeding working oil to an oil chamber 6 from a hydraulic pump 8 so as to extend a cylinder unit 4. This constitution can prevent working oil positively from being abruptly increased in its pressure even if the levelling valves 16, 29, and 33 and the unloader valve 38 are errorneously operated.

Description

[Detailed Description of the Invention] <Industrial Application Fields> The present invention relates to a vehicle height adjustment system that adjusts the vehicle height by controlling the supply and discharge of hydraulic fluid to a cylinder unit provided between the wheels of a vehicle and a heavy object. This invention relates to an improved technique for adjusting devices.

(Prior Art) This type of vehicle height adjustment device has been generally well known. For example, in Japanese Utility Model Application Publication No. 57-176310, a cylinder unit such as a respension unit is provided between the vehicle body and the wheels of an automobile, and a variable volume oil chamber in the cylinder unit is connected through a first communication path. A first communication passage for supplying hydraulic oil is connected to the hydraulic pump and the first communication passage is connected to the hydraulic pump.
A switching valve is provided, and a first communication path between the first switching valve and the hydraulic pump is communicated with the reserve tank via a second communication path, and the first communication path is connected to the reserve tank through a second communication path. A second switching valve for hydraulic oil drain is provided, and by opening the first switching valve and closing the second switching valve, hydraulic oil is supplied from the hydraulic pump to the oil chamber of the cylinder unit, and the cylinder unit is drained. While the vehicle height is raised by the extension action, the hydraulic oil in the oil chamber is discharged into the reserve tank by opening both switching valves, and the vehicle height is lowered by the contraction action of the cylinder unit 1-. Disclosed.

(Problems to be Solved by the Invention) By the way, in the vehicle height adjustment device that adjusts the vehicle height by controlling the supply and discharge of hydraulic fluid to the cylinder fluid chambers of the cylinder units 1 to 1, it is difficult to increase the vehicle height. When adjusting,
Ideally, the opening timing of the first switching valve described above and the closing timing of the second switching valve should exactly match, but in reality there is a time difference between the two timings due to valve operation errors. This may occur. In that case, there is no problem if the opening timing of the first switching valve is earlier than the closing timing of the second switching valve, but conversely, the closing timing of the second switching valve is earlier than the closing timing of the first switching valve. When this occurs, the pressure of the hydraulic oil in the communication path between the pump and both switching valves increases rapidly, resulting in an excessive load on the pump and seizure. There is a risk.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to appropriately regulate the timing of opening and closing of both switching valves provided in the communication path between the pump, reserve tank, and cylinder unit in the vehicle height adjustment device described above. To reliably prevent the communication path between a pump and both switching valves from becoming an open circuit, regardless of an operational error in the opening/closing timing of both switching valves when adjusting the increase in vehicle height. There is a particular thing.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides a variable volume cylinder liquid chamber between the support member that supports the wheels of the automobile and the vehicle body, as described above. A cylinder unit is provided, and a cylinder liquid chamber of the cylinder unit is provided with
A pump for pressure-feeding the working fluid in the reserve tank is communicated via the communication path @1, and the first communication path is connected to the
A second communication path that connects the first communication path to the reserve tank is branched and connected. Further, a first switching valve for opening and closing the communication passage is provided in the first communication passage between the connection portion of the second communication passage and the cylinder liquid chamber of the cylinder unit, and a first switching valve for opening and closing the communication passage is provided in the second communication passage. By providing a second 1.11 switching valve ↑ that opens and closes, and opening the first switching valve and closing the second switching valve, the liquid pumped under pressure from the pump is transferred to the cylinder liquid chamber of the cylinder unit. The hydraulic fluid is supplied to the cylinder unit to raise the vehicle height, while the hydraulic fluid of the cylinder unit is discharged to the reserve tank to lower the vehicle height by controlling both the first and second switching valves. .

And a car with the above configuration 7. '! For the i adjustment device, an R extending means is installed to adjust the closing timing of the second switching valve to a predetermined period of time with respect to the distance timing of the first switching valve. I will do something.

(Function) According to the above configuration, in the present invention, when the vehicle height increases, the first
At the same time, the second switching valve is closed, and the hydraulic fluid discharged from the pump is supplied to the cylinder fluid chamber of the cylinder unit interposed between the 41 body and the wheels. As the volume of the chamber increases, the cylinder unit expands, causing the vehicle height to rise.

In that case, the delay means forcibly delays the closing timing of the second switching valve by a predetermined period of time compared to the opening timing of the first switching valve, so that even if there is an operational error in both switching valves, it will not be affected. Regardless, it is certain that the second switching valve will close after the first switching valve has heard, and the communication path between the pump and both switching valves will become an open circuit, and the pressure of the hydraulic fluid will suddenly increase. This will prevent it from rising.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the mechanical parts of a vehicle height adjustment device according to an embodiment of the present invention, in which 1 is a vehicle body at the left front wheel, which is typically exemplified in an automatic vehicle, 2 is a wheel (left front wheel), and 3 is the wheel. A cylinder unit 4 is provided between the upper end of the wheel axle 3 and the vehicle body 1 above it. The cylinder unit 4 has a cylinder body 4a whose lower end is fixed to the wheel axle 3.
a piston 4b fluid-tightly fitted into the cylinder body 4a so as to be able to reciprocate; and a piston rod 4C whose lower end is connected to the piston 4b and whose L end is supported by the vehicle body 1 via the mount 5. Consisting of

In the cylinder body 4a, an oil chamber 6 is formed as a cylinder liquid chamber with a variable volume and partitioned by a piston 4b. 3 and the piston rod 4C through an oil passage (not shown) formed therethrough, the piston rod 4C is communicated with a piping connection portion 4d of the upper valve.

Although not shown, the structure of other wheel parts of the automobile is also constructed in the same manner as the left front wheel part.

7 is a hydraulic control unit connected to the piping connection 4d of the registered cylinder unit 4, and the hydraulic control unit 7 is equipped with a hydraulic pump 8 driven by an on-vehicle engine (not shown). The hydraulic pump 8 is connected to a power steering hydraulic pump 9. The suction side of the hydraulic pump 8 is connected to the reserve tank 11 via a suction passage 10 together with the suction side of the power steering hydraulic pump 9, while the discharge side has a main passage 12 and a branch valve 13.
The front and rear intermediate passages 14 and 15 are branched and connected via the intermediate passages 14 and 15 on the front side and the rear side. The diverting valve 13 divides the hydraulic oil evenly into the intermediate passages 14 and 15 even if the pressure of the hydraulic oil or the pump load fluctuates.

A leveling valve 16 as a first switching valve is disposed in the middle of the intermediate path 14 on the front side. The leveling valve 16 is a spring-offset type electromagnetic switching valve having 2 points and 2 positions. In its normal position, it is closed and the intermediate passage 14 is opened, and in its offset position, it is opened and the intermediate passage 14 is opened. It is made to open.

In addition, right side and left side branch passages 18 and 19 are connected to the intermediate passage 14 via a branch valve 17 having the same function as the branch flow # 13, and one branch passage on the reflex 1 to left side branches. communicates with the oil chamber 6 of the cylinder unit 4 in the left front wheel portion.

The branching path 19 is connected to the cylinder unit 4 from the branch valve 17.
Flow a control valve 20 and variable damping force valve 2 in order toward the side.
1 is provided, the 'am control valve 20 and the variable damping force valve 21
A gas spring 22 is branch-connected to the branch path 19 between the two. The flow control valve 20 includes a check valve 20a that allows hydraulic oil to flow only from the oil pressure source side to the cylinder unit 4 side, and a relief valve 20b and a throttle valve 20c that are connected so as to bypass the check valve 20a. Thus, the flow ω of the hydraulic oil returning from the oil chamber 6 of the cylinder unit 4 to the reserve tank 11 on the hydraulic pressure source side is adjusted. Further, the gas spring 22 has a sealed casing 22a partitioned into a gas chamber 22c and an oil chamber 22d by a diaphragm 22b.The gas chamber 22c is filled with gas such as nitrogen gas, and the oil chamber 2
2d is connected to a branch path 19, and the load input to the cylinder unit 4 from the vehicle body 1 and wheels 2 is transferred to the gas chamber 22c.
It is absorbed by the elasticity of the gas inside. Further, the damping force variable valve 21 includes a damping force generating valve, shown in FIG. and
By changing the passage area of the bypass passage using the damping force control valve, the oil flowing through the damping force generating valve is adjusted to variably control the damping force for the vertical movement of the wheel 2.

Further, the right side branch passage 18 is connected to the oil chamber of the cylinder body 1 to J3 in the right front wheel portion (not shown), and the branch passage 18 is connected to a flow control valve 23 having the same configuration as above.
J3 and a variable damping force valve 24 are provided, and a gas spring 25 is connected.

On the other hand, right side and left side branch passages 27 and 28 are connected to the rear intermediate passage 15 via a diversion valve 2G having the same function as the diversion valve 13, and the right side branch passage 27 is connected to the oil chamber of the cylinder unit in the right rear wheel section (not shown), and the left side branch passage 28 is similarly connected to the oil chamber of the cylinder unit in the left rear wheel section. Further, a leveling valve 29 as a first switching valve having the same configuration as the leveling valve 16 is disposed in the light side branch path 27.
The branch passage 27 on the cylinder unit side is equipped with a flow control valve 30 similar to the one described above. A gas spring 32 and a variable damping force valve 31 are provided.

In addition, the right side branch road 2 is also connected to the left side branch road 28.
7, the leveling valve 33 (first switching valve), the flow m
A control valve 34, a gas spring 36, and a variable damping force valve 35 are provided. Therefore, in this embodiment, the main path 12.
Intermediate road 14.15 and branch road 18, 19.27.28
constitutes the first communication path in the present invention.

Furthermore, the main path 1 between the hydraulic pump 8 and the diverter valve 13
A return path 37 as a second communication path that communicates with the reserve tank 11 is branched and connected to 2 (first communication path),
An unload valve 38 serving as a second switching valve is disposed in the middle of the return path 37. The unload valve 38 is a 2-point, 2-position spring offset type electromagnetic switching valve, in its normal position it is open and closes the return path 37, and in its offset position it is open and opens the return path 37. is being done.

And the front side and rear side leveling valves 16,
29.33 and the unload valve 38 control the supply and discharge of hydraulic oil to the oil chamber 6 of the cylinder unit 4 in each wheel portion, open the leveling valves 16 and 29.33, close the unload valve 38, and control the oil pressure. By supplying the hydraulic oil discharged from the pump 8 to the oil chamber 6 of each cylinder unit 4, the volume of the oil chamber 6 is increased and the vehicle height is raised. Both valves 38 and each cylinder unit 4
By returning the hydraulic oil in the oil chamber 6 to the reserve tank 11, the volume of the oil chamber 6 is reduced and the vehicle height is lowered.

Note that the right side branch passage 18 between the flow rate control valve 23 and the gas spring 25 connection part and the one left side branch passage between the flow rate control valve 20 and the gas spring 22 connection part are the communication passage 4.
0, and an anti-roll valve 41 is disposed in the middle of the communication path 40. The anti-roll valve 41 is a two-bottom, two-position spring offset type electromagnetic switching valve, and in its normal position, it is in an open state and the communication passage 40 is closed.
is opened to allow hydraulic oil to flow between both branch passages 18 and 19, while in the offset position it is closed to close the communication passage 40 and prevent hydraulic oil from flowing between both branch passages 18 and 19. .

The above leveling valve 16, 29, 33, unloading valve 38
, the variable damping force valves 21.24, 31.35, and the anti-roll valve 41 are operated and controlled by a control unit 42 as shown in FIG.

The control unit 42 includes a vehicle height sensor 41111 that detects the actual 1'II height of each wheel based on, for example, the rotation angle of the lower arm shade that suspends and supports the wheels.
．． /13. ... (only one is shown) is input, and the control unit 42 compares the target vehicle height value with the actual vehicle height value detected by the Φ height sensor 43, and determines the actual vehicle height value. is lower than the target vehicle height value, a signal to open the leveling valves 16, 29, 33 and a signal to close the unloading valve 38 are output to raise the middle height by F. When the vehicle height value is higher than the target vehicle height value, a signal is output to both the leveling valve 16, 29, 33 and the unloading valve 38 to open them, thereby lowering the vehicle height.

Furthermore, when the vehicle height increases, the control unit 42 controls the closing timing of the unloading valve 38 by a predetermined time (for example, 200 m5ec) compared to the opening timing of the leveling valve 16.29° 33, as shown in FIG. A timer 44 is built in as a delay means.

Therefore, in the above embodiment, the control unit 42 receives the detection signal from the vehicle height sensor 43 and controls the opening and closing of the leveling valves 16, 29, 33 and the unloading valve 38 to adjust the vehicle height. That is, the actual vehicle height value detected by the vehicle speed sensor 43 is (1
When raising the vehicle height below the target vehicle height, the leveling valves 16, 29, 33 are opened and the unloading valve 38 is closed, and the hydraulic fluid discharged from the hydraulic pump 8 is transferred to the main path 12, Intermediate road 14.15 and branch road 18,
19, 27, and 28 to the oil chamber 6 of each cylinder unit 4, thereby increasing the volume of the oil chamber 6, extending the cylinder unit 4, and raising the vehicle height.

At that time, the timer 44 in the control unit 42
Accordingly, the unloading valve 38 becomes the leveling valve 16.2.
9. Predetermined time (200m5ec) than the interval operation of 33
It is only after a delay that it is intercepted. For this reason, the leveling valve 16,
29. Even if there is an operation error in 33 and the unload valve 38, the fJl timing of the unload valve 38 is the same as that of the leveling valve 1.
6.29.33, the main passage 12, intermediate passages 14, 15, leveling valve 29.
33 and the branch valve 26 and the return passage 37 upstream of the unload valve 38, the hydraulic oil is trapped in the return passage 37 and its pressure does not rise suddenly, thereby reducing the load on the hydraulic pump 8. It is possible to reduce the damage, prevent seizure, etc., and improve durability.

On the other hand, if the actual vehicle height value is higher than the target vehicle height value and the vehicle height is to be lowered, the leveling valve 16.29
．． 33 and unload valve 38 are closed almost simultaneously, and due to the load received from the vehicle body 1, each cylinder unit 4
The hydraulic oil in the oil chamber 6 is controlled by several sets of control valves 20, 23, 30, 3.
4, while the flow rate is being adjusted at branch roads 18, 19, 27, 28, contrary to the case when the vehicle height is raised. The oil is returned to the reserve tank 11 via the intermediate passage 14, 15, the main passage 12, and the return passage 37, thereby reducing the volume of the oil chamber 6, contracting the cylinder unit 4, and lowering the vehicle height.

In the above embodiment, a vehicle height adjustment device that adjusts the vehicle height using hydraulic oil has been described, but the present invention is applicable to an FJ height adjustment device that uses a liquid other than hydraulic oil to adjust the vehicle height. Of course, it can also be applied to

(Effects of the Invention) As described above, according to the present invention, the vehicle height is adjusted by controlling the supply and discharge of hydraulic fluid to the cylinder fluid chamber of the cylinder unit interposed between the vehicle body and the wheels. In the device, when the vehicle height is adjusted to rise, one meter is set to drain the hydraulic fluid from the pump into the reserve tank at the opening timing of the switching valve for supplying the hydraulic fluid from the pump to the cylinder fluid chamber of the cylinder unit. By controlling the valve closing timing late, the communication path between the pump and both switching valves becomes a closed circuit, and the pressure rises rapidly, regardless of the operating error of both switching valves. It is possible to reliably prevent J1, thereby stably reducing the pump load and improving its durability.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory diagram showing a cylinder unit provided between a wheel and a vehicle body and a hydraulic control unit connected to its oil chamber, and FIG. 2 is a schematic configuration of the control system. Figure 3 is a block diagram showing the opening of the leveling valve and unloading valve at 17 o'clock above the vehicle height! It is an explanatory diagram showing one period. DESCRIPTION OF SYMBOLS 1...Vehicle body, 2...Wheel, 3...Wheel axle, 4-way cylinder unit, 6...Oil chamber, 7...Hydraulic control unit, 8...Hydraulic pump, 11... Reserve tank, 12...Main road, 14.15...Intermediate road, 18,1
9,27゜28... Branch road, 37... Return road, 16
．． 29.33...Leveling valve, 38...Unload valve, 42...Control unit, 43...Vehicle height sensor, 44...Timer. Patent applicant: Mazda Motor Corporation Ne1 patent application
Request Person: Power V Baegyo Co., Ltd. - Agent
In front of people 1) Hiroshi □ ″(
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Claims (1)

[Claims] (1) A cylinder unit that is provided between the support member that supports the wheels and the vehicle body and has a cylinder liquid chamber whose volume can be changed, and a pump that pumps the hydraulic fluid in the reserve tank to the cylinder liquid chamber of the cylinder unit. a first communication path that communicates with the reserve tank; a second communication path that is branched and connected to the first communication path and communicates the first communication path with the reserve tank; and a connecting portion of the second communication path; a first switching valve that opens and closes the first communication passage between the cylinder liquid chamber of the cylinder unit; and a second switching valve that opens and closes the second communication passage; By opening the switch valve and closing the second switching valve, the hydraulic fluid pumped from the pump is supplied to the cylinder liquid chamber of the cylinder unit to raise the vehicle height. In a vehicle height adjustment device for a vehicle that lowers the vehicle height by discharging the hydraulic fluid in the fluid chamber into a reserve tank, when the vehicle height increases, the closing timing of the second switching valve is changed to that of the first switching valve. A vehicle height adjustment device for an automobile, characterized in that a delay means for delaying the opening timing by a predetermined period of time is provided.