JPS6294412A - Car height adjustor for car - Google Patents

Abstract

PURPOSE:To improve the responsiveness in car height adjustment and the traveling stability in high-speed traveling by controlling the quantity of working liquid supplied into a cylinder unit arranged between a wheel supporting member and a chassis so as to increase in low speed traveling and reduce in high-speed traveling. CONSTITUTION:When the car height is increased, the levelling valves 16, 29, and 33 of a hydraulic control unit 7 are opened, and an unloading valve 38 is closed. The working oil discharged from a hydraulic pump 8 is supplied into the oil chamber 6 of each cylinder unit 4 through a main passage 12, intermediate passages 14 and 15, and each branched passage 18, 19, 27, 28. Therefore, the cylinder unit 4 is extended by increasing the capacity of the oil chamber 6, and the height of a chassis 1 is increased. In this case, the quantity of the working oil supplied into each cylinder unit 4 from the hydraulic pump 8 is varied by a flow control valve 42 according to the car speed corresponding to the engine speed. As the car speed increases, the supply quantity of working oil is reduced.

Description

Detailed Description of the Invention (Industrial Application Field) 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 and the vehicle body of a vehicle. 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, Japanese Utility Model Application Publication No. 57-176310 discloses that a cylinder unit as a suspension unit is provided between the vehicle body and the wheels of an automobile, and hydraulic oil is supplied from a hydraulic pump to a variable volume oil chamber in the cylinder unit.
Alternatively, a vehicle height adjustment system has been disclosed in which the vehicle height is adjusted by discharging the hydraulic oil in the oil chamber into a reserve tank.

(Problems to be Solved by the Invention) By the way, in a vehicle height adjustment device that adjusts the vehicle height by controlling the supply and discharge of hydraulic fluid to and from the cylinder fluid chamber of the cylinder unit, normally, the vehicle height is adjusted by controlling the supply and discharge of hydraulic fluid to the cylinder fluid chamber of the cylinder unit. The discharge amount of the pump that supplies the working fluid is kept constant. When setting the pump discharge amount, from the perspective of speeding up vehicle height adjustment, it is preferable to increase the pump discharge amount as much as possible, and when the vehicle height increases, the target vehicle height value (leveling position) It is possible to shorten the time it takes to reach . However, if this happens, the height of the vehicle will rise rapidly even when the vehicle is running at high speeds, which is disadvantageous in ensuring running stability.

Conversely, in order to ensure running stability at high vehicle speeds,
If the pump discharge rate is kept low, it will be difficult to quickly raise the vehicle height to the target vehicle height value at low vehicle speeds, and therefore,
In a flat state, the pump discharge amount is generally set so as to approximately satisfy two contradictory requirements.

Therefore, an object of the present invention is to make the amount of hydraulic fluid supplied from the pump to the cylinder unit in the vehicle height adjustment device variable, and to correlate it with the vehicle speed, thereby improving the speed at low vehicle speeds. To sometimes quickly raise the vehicle height to shorten the time it takes to reach the target vehicle height, and conversely to suppress rapid increases in vehicle height at high vehicle speeds to ensure vehicle running safety - 3 constancy. It is in.

(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 body 1- is provided, and a cylinder liquid chamber of the cylinder unit is connected to a reserve tank in which hydraulic fluid is stored and a pump that pressure-feeds the hydraulic fluid in the reserve tank through a supply/discharge valve means. The vehicle height adjustment device adjusts the vehicle height by supplying and discharging hydraulic fluid to and from the cylinder liquid chamber of the cylinder unit using the supply and discharge valve means. The supply amount variable means is configured to increase the amount of hydraulic fluid supplied when the vehicle is running at a low speed, and to decrease it when the vehicle is running at a high speed.

(Function) With the above configuration, in the present invention, when the vehicle height is at the upper side, the pump is controlled to discharge from the pump by the supply/discharge valve means.
- The discharged hydraulic fluid is supplied to the cylinder fluid chamber of the cylinder unit interposed between the vehicle body and the wheels, and as the volume of the cylinder fluid chamber increases, the cylinder unit expands and the vehicle height increases.

In that case, the amount of hydraulic fluid supplied from the pump to the cylinder liquid chamber of the cylinder unit is controlled by the supply amount variable means in accordance with the vehicle speed. Sometimes the supply is changed to be less. Therefore, when the vehicle speed is low, the hydraulic fluid is rapidly supplied to the cylinder liquid chamber of the cylinder unit, so that the vehicle height can be quickly raised to the target vehicle height value, and the time required to reach the target vehicle height value can be shortened. On the other hand, when the vehicle speed increases, the amount of hydraulic fluid supplied from the pump decreases, suppressing a sudden increase in vehicle height, thereby ensuring running stability at high vehicle speeds.

<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 a typical left front wheel of an automobile, 2 is a wheel (left front wheel), and 3 is the wheel 2. A cylinder unit 4 is provided between the upper end of the wheel axle 3 and the heavy 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 upper end is supported by the vehicle body 1 via the mount 5. Become.

Oil chamber 6 as a cylinder liquid chamber with variable volume divided by the cylinder body
The oil chamber 6 is connected to the piston rod 4 through an oil passage (not shown) formed through the piston 4b and the piston rod 4c. c J: Communicated with the end piping connection part 4d. 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.

Reference numeral 7 denotes a hydraulic control unit connected to the piping connection portion 4d of each cylinder unit 4, and the hydraulic control unit 7 includes a hydraulic pump 8 driven by an on-vehicle engine (not shown). is connected to the power steering hydraulic pump 9.The suction side of the hydraulic pump 8 and the suction side of the power steering hydraulic pump 9 are connected to a reserve tank 11 via a suction passage 10, while the discharge side Intermediate passages 14 and 15 on the front side and the rear side are branched and connected to the main passage 12 and a diverter valve 13. This is to equally divide the flow into intermediate paths 14 and 15.

A leveling valve 1 is located in the middle of the intermediate passage 14 on the front side.
6 are arranged. The leveling valve 16 has two ports 2
It consists of a spring-off cella 1-type electromagnetic switching valve having a position, and in its normal position, it is in a closed state and intermediate path 1 is closed.
/I is closed and opened at the offset position to open the intermediate path 14.

In addition, the intermediate passage 14 has the same valve as the diverter valve 13 7
Right-side and left-side branch passages 18 and 19 are branched and connected via a diverter valve 17 having a uniform function, and the left-side branch passage 19 communicates with the oil chamber 6 of the cylinder unit 4 in the left front wheel portion. has been done.

The branching path 19 is connected to the cylinder unit 4 from the branch valve 17.
Flow rate control valve 2o and damping force variable valve 2 in order toward the side.
1 is disposed, and a gas spring 22 is branch-connected to a branch path 19 between the flow rate control valve 2o and the variable damping force valve 21. The flow rate 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 2ob and a throttle valve 20c that are connected to bypass the check valve 2a. It adjusts the flow rate of hydraulic oil returning from the oil chamber 6 of the cylinder unit 4 to the reserve tank 11 on the oil pressure source side. 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 22
d communicates with the branch path 19, and the cylinder unit 4
The load input from the car-8 unit 1 and the wheels 2 is absorbed by the elasticity of the gas in the gas chamber 22c. Further, the damping force variable valve 21 includes a damping force generating valve (not shown) consisting of a pair of check valves, and a plurality of damping force control valves disposed in a bypass path that bypasses the damping force generating valve. The damping force for the vertical movement of the wheels 2 is variably controlled by adjusting the amount of oil flowing through the damping force generating valve by changing the passage area of the bypass passage using the damping force control valve.

The right-side branch passage 18 is connected to the oil chamber of the cylinder unit located in the right front wheel (not shown), and the branch passage 18 includes a flow control valve 23 having the same configuration as above and a variable damping force valve. A valve 24 is 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 branch valve 26 having the same function as the distribution valve 13, and the right side branch passage 27 is connected to an oil chamber of a cylinder unit located at the right rear wheel (not shown), and the left side branch passage 28 is similarly connected to an oil chamber of a cylinder unit located at the left rear wheel. In addition, a leveling valve 2 having the same configuration as the leveling valve 16 is provided in the branch path 27 on the light side.
9 is disposed, and a flow control valve 30 similar to the above is provided in the branch passage 27 on the cylinder unit side from the leveling valve 29.
．． A gas spring 32 and a variable damping force valve 31 are provided. In addition, the left side branch path 28 also has a leveling valve 33, a flow rate control valve 34,
A gas spring 36 and a variable damping force valve 35 are provided.

Furthermore, the main path 1 between the hydraulic pump 8 and the diverter valve 13
A return path 37 that communicates with the reserve tank 11 is branched to 2, and an unload valve 3 is connected in the middle of the return path 37.
8 are arranged. The unload valve 38 has two ports 2
In its normal position, it is in a closed state and closes the return path 37.
At the offset position, an opening operation is performed to open the return path 37.

and front side and rear side leveling valves 16.
29.33 and the unload valve 38 to control the supply and discharge of hydraulic oil to the oil chambers 6 of the cylinder units] to 4 in each wheel portion, open the leveling valves 16, 29, and 33, and close the unload valve 38. By supplying the hydraulic oil discharged from the hydraulic 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. By opening both unload valves 38 and returning the hydraulic oil in the oil chamber 6 of each cylinder unit 4 to the reserve tank 11, the volume of the oil chamber 6 is reduced and the vehicle height is lowered. There is.

The right side branch passage 18 between the flow rate control valve 23 and the gas spring 25 connection part and the left side branch passage 19 between the flow rate control valve 20 and the gas spring 22 connection part are the communication passage 4.
0, and an anti-roll 41 is disposed in the middle of the communication path 40. The anti-roll valve 41 is a 2-point, 2-position spring offset type electromagnetic switching valve, and in its normal position, it is in an open state and the communication path 4 is opened.
0 is opened to allow hydraulic oil to flow between both branch passages 18 and 19, while in the offset position it is closed and the communication passage 40 is opened.
This closes the branch passages 18 and 19 to prevent hydraulic oil from flowing between them.

Furthermore, as a feature of the present invention, a hydraulic pump 8 is provided in the main passage 12 between the hydraulic pump 8 and the connection part to the return passage 37.
The hydraulic oil discharged from the oil chamber 6 of each cylinder unit 4
A flow control valve 42 is provided as a supply amount variable means for changing the supply amount to the engine in accordance with the engine speed, which approximately corresponds to the vehicle speed of the automobile.

The flow control valve 42 includes a cylindrical valve housing 43, as shown in enlarged detail in FIG. A bypass port 45 communicating with the suction side (suction passage 10) is provided on one side wall on the center line (the right side wall in the figure), and a discharge port 46 communicating with the diverting valve 13 is opened in the valve housing 43.
The inflow boat 44 and bypass port 4 are inside the inflow boat 44 and the bypass port 4.
An orifice 47 is formed by partially narrowing the communication path between the discharge port 5 and the discharge port 46. Further, a valve body 48 is slidably fitted in the valve housing 43 on the opposite side of the discharge port 46 with respect to the orifice 47, and the valve body 48 is fitted between the valve body 48 and the other side wall in the housing 43. It is biased toward the orifice 47 (to the right in the figure) by a flow control spring 50 housed in the spring storage chamber 49. Furthermore, a stepped portion 51 for narrowing the orifice 47 is coaxially attached to the end of the valve body 48 opposite to the spring storage chamber 49 via a rod 52. As shown in FIG. 3, when the vehicle speed of the vehicle is low, that is, the rotation speed of the vehicle engine, which corresponds to the vehicle speed on average, is low, and the amount of hydraulic fluid discharged from the hydraulic pump 8 is small, the flow By biasing the valve body 48 to the right in FIG. 2 by the biasing force of the control spring 50 and closing the bypass port 45 with the valve body 48, the flow from the hydraulic pump 8 through the inflow port 44 into the housing 43 is caused. The introduced hydraulic oil is passed through the orifice 47 and distributed to the discharge port 46, and the pump 8
From this, the amount of hydraulic oil supplied to the oil chamber 6 of the cylinder unit 4 in each wheel portion is increased. On the other hand, when the vehicle speed is high, that is, the engine speed increases and the amount of hydraulic oil discharged from the hydraulic pump 8 increases, the pressure difference P (=
P+ -P2) is increased to move the valve body 48 to the left in the figure against the biasing force of the flow control spring 50, and the stepped portion 51 reduces the opening area of the orifice 47 to reduce the pressure difference P. By opening the bypass port 45 while further increasing the pressure, the hydraulic pump 8
The surplus amount of hydraulic oil from the pump 8 is returned to the reserve tank 11 via the bypass port 45 to reduce the amount of hydraulic oil supplied from the pump 8 to the oil chamber 6 of the cylinder unit 4.

A valve chamber 53 is formed in the valve body 48 and communicates with the spring storage chamber 49 in the valve housing 43 and the bypass port 45, respectively.
The relief valve 5 opens the communication port 53a with the four spring storage chambers by the urging force of the relief spring 54.
5 is stored. In addition, the spring storage chamber 49
is communicated with the discharge port 46 through a communication passage 43a formed through the valve housing 43, and when the hydraulic pressure in the discharge port 46, that is, in the main passage 12 communicating with the discharge port 46 rises above a predetermined pressure, The relief valve 55 is opened against the biasing force of the relief spring 54, and the hydraulic oil in the discharge port 46 is transferred to the communication path 43a, the spring storage chamber 49. The maximum oil pressure in the main passage 12 is controlled by returning the oil to the reserve tank 11 via the valve chamber 53 and bypass port 45.

Therefore, in the above embodiment, the leveling valve 16
, 29, 33 and the unload valve 38 to adjust the vehicle height. That is, when raising the vehicle height, the leveling valves 16, 29, and 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 path 14, . ．． 1
5 and branch passages 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 this time, by operating the flow control valve 42, the amount of hydraulic oil supplied from the hydraulic pump 8 to the oil chamber 6 of each cylinder unit 4 changes in accordance with the vehicle speed, which roughly corresponds to the engine rotational speed. At times, the amount supplied increases, and as the vehicle speed increases, the amount supplied decreases. Therefore, at low vehicle speeds, hydraulic oil is rapidly introduced into the oil v6 of each cylinder unit 4, increasing the extension speed of cylinder unit l-4, and shortening the time it takes for the vehicle height to reach the target vehicle height value. This makes it possible to quickly raise the vehicle height. On the other hand, at high vehicle speeds, the introduction speed of hydraulic oil into the oil chambers 6 of each cylinder unit 4 becomes low, so the extension speed of the cylinder units 4 also slows down, suppressing a sudden rise in vehicle height. It is possible to ensure running stability.

On the other hand, when lowering the vehicle height, both the leveling valve 16, 29, 33 and the unloading valve 38 are opened, and the load received from the vehicle body 1 causes the oil chamber 6 of each cylinder unit 4 to operate. Oil flow control valve 20.23.30
．． While adjusting the flow rate at 34, the branch road 18° 19.27.28. Middle road 14, 15,
Reserve tank 11 via main path 12 and return path 37
As a result, the volume of the oil chamber 6 decreases, the cylinder unit (4) contracts, and the vehicle height decreases.

In the above embodiment, the flow control valve 42 is connected to the discharge side of the hydraulic pump 8, and the supply of hydraulic oil from the hydraulic pump 8 to the oil chamber 6 of the cylinder unit 4 is controlled at an engine rotational speed that substantially corresponds to the vehicle speed. I tried to change it accordingly, but
The hydraulic pump itself may be of a variable displacement type, and its discharge value may be changed in accordance with the engine speed (vehicle speed). Furthermore, by directly detecting the vehicle speed using a vehicle speed sensor, etc., and adjusting the operating amount tm of the appropriate valve device based on the output signal of the sensor, etc., the amount of hydraulic oil supplied to each cylinder unit 4 is adjusted according to the vehicle speed. You can also avoid changes.

Further, 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 directed to a vehicle 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, the amount of hydraulic fluid supplied from the pump to the cylinder fluid chamber of the cylinder unit is variably controlled according to the vehicle speed, increasing at low vehicle speeds and decreasing at high 1'i speeds. At low vehicle speeds, the vehicle height can be rapidly raised to the target vehicle height value, reducing the time it takes to reach the target vehicle height value. This makes it possible to ensure running stability.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory diagram showing the cylinder unit aUGJ installed between the middle wheel and the vehicle body and the hydraulic control unit 1 connected to its oil chamber, and FIG. FIG. 3, which is an enlarged sectional view of the valve, is a characteristic diagram showing the change characteristics of the amount of hydraulic oil supplied with respect to the engine speed. 1...Vehicle body, 2...Wheel, 3...Wheel axle, 4...
・Cylinder 1-nit, 6... Oil chamber, 7... Hydraulic control unit, 8... Hydraulic pump, 11... Reserve tank, 16° 29.33... Leveling valve, 38
...Unload valve, 42... Fuko control valve, 47... Orifice, 48... Valve body, 51...
・Stepped part.

Claims (1)

[Claims] (1) A cylinder unit having a cylinder liquid chamber whose volume can be changed is disposed between the support member that supports the wheels and the vehicle body, and the cylinder liquid chamber of the cylinder unit, a reserve tank in which hydraulic fluid is stored, and A pump for pressure-feeding the hydraulic fluid in the reserve tank is communicated with the pump through a supply/discharge valve means, and the supply/discharge valve means controls the supply/discharge of hydraulic fluid to and from the cylinder fluid chamber of the cylinder unit to adjust the vehicle height. In the vehicle height adjustment device for an automobile, the amount of hydraulic fluid supplied from the pump to the cylinder liquid chamber of the cylinder unit is increased when the vehicle is running at low speeds, and is decreased when the vehicle is at high speeds. A vehicle height adjustment device for an automobile, characterized in that a supply amount variable means is provided.