JPH0237612Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a hydraulic vehicle height adjustment for automobiles that minimizes the pressure loss between the pump and the plunger at low temperatures and efficiently operates the vehicle height adjustment cylinder. This relates to the hydraulic circuit of the device.

Prior Art In an automobile, a vehicle height adjustment mechanism consisting of a hydraulic cylinder device is incorporated into the suspension system of each front, rear, left, and right wheel, and the operation of an oil pump is controlled by a signal from a vehicle height sensor provided on each wheel. A vehicle in which the vehicle height can be changed by controlling the increase or decrease of oil in a hydraulic cylinder is already known, for example, in Japanese Patent Application Laid-Open No. 178911/1983.

In addition, in a hydraulic vehicle height adjustment device in which an oil pump is activated to raise the vehicle height to a predetermined value by turning on a vehicle height adjustment switch, the oil supply path supplies oil from the oil pump to each hydraulic cylinder device. By providing an oil pressure switch that operates at a set oil pressure value higher than the oil pressure value required for each hydraulic cylinder device to extend, the one oil pressure switch can restore the vehicle body posture to normal. The applicant developed a control device for a hydraulic vehicle height adjustment device that functions as a vehicle height sensor that detects the oil pump and stops the oil pump.
An application for utility model registration has already been filed as No. 158998.

Problems that the invention aims to solve: In the hydraulic circuit of the hydraulic vehicle height adjustment system as described above, the pressure loss between the oil pump and each hydraulic cylinder becomes large at low temperatures. Even if the necessary pressure is generated, the hydraulic cylinder portion may not generate enough pressure to adjust the vehicle height due to pressure loss in the hydraulic circuit. If you use low viscosity oil with less pressure loss at low temperatures to solve these problems,
On the other hand, the viscosity of the oil decreases rapidly at high temperatures, making it impossible to secure the hydraulic pressure required for vehicle height adjustment due to the structural limitations of gear pumps, which are commonly used as oil pumps. There is.

Means for Solving the Problems In the present invention, as shown in FIG. One chamber partitioned in the case communicates with an oil pump device consisting of an oil pump and an oil tank, and the other chamber communicates with each hydraulic cylinder device for adjusting vehicle height. High viscosity oil, which has conventionally been used in hydraulic vehicle height adjustment devices, is used, and low viscosity oil is used in the hydraulic circuits on each hydraulic cylinder device side.

Function The present invention adopts the above configuration, so that
At high temperatures, the conventional high viscosity oil can be used in the oil pump system, so the oil pump's discharge capacity required for vehicle height adjustment can be maintained sufficiently high, and even at low temperatures, the oil pump can be used from the plunger case to each hydraulic cylinder system. Pressure loss in the hydraulic circuit from the oil pump to the plunger case is reduced by using low-viscosity oil, and the use of high-viscosity oil is limited to the hydraulic circuit from the oil pump device to the plunger case, minimizing the overall pressure loss. Therefore, each hydraulic cylinder device can be operated efficiently.

Embodiments The details of the present invention will be explained below with reference to embodiments shown in the accompanying drawings.

In FIG. 1, 1 is an oil pump device, 2 is a plunger case, and the plunger case 2
A plunger 3 is slidably fitted inside the plunger case 2, and the space inside the plunger case 2 is divided into a left chamber 4 and a right chamber 5.
It is divided into two rooms. High viscosity oil, which has been conventionally used in hydraulic vehicle height adjustment devices, is supplied to the left chamber 4 from an oil pump device 1 via a pipe 6. The right chamber 5 is connected via a pipe 7 to hydraulic cylinder devices 8 and 9 for adjusting the vehicle height of the front and rear wheels, and low viscosity oil is used in this hydraulic system. The piping 7 is provided with an oil pressure switch 10 which detects the oil pressure in the piping 7 and operates. Also, low viscosity oil is supplied to the right chamber 5 in the plunger case 2 from a reservoir tank 11 via a check valve 12.

When the vehicle height adjustment switch is turned on and the oil pump (not shown) in the oil pump device 1 rotates in one direction, the high viscosity oil in the oil pump device 1 flows through the pipe 6 into the left chamber 4 in the plunger case 2.
The plunger 3 is moved to the right by the hydraulic pressure generated in the left chamber 4. Above plunger 3
The low viscosity oil that was in the right chamber 5 in the plunger case 2 due to the movement to the right is supplied to each hydraulic cylinder device 8, 9 through piping 7, and the increases, and when the oil pressure reaches a predetermined pressure (P ₁ in FIG. 2), each hydraulic cylinder device expands under the weight and weight of the vehicle and begins to raise the vehicle height. During this operation, the operating stroke required for adjusting the vehicle height of each hydraulic cylinder device is approximately constant, and during the extension operation, the oil pressure in the pipe 7 is approximately constant pressure P ₁ as shown in Fig. 2. ing.

When all the hydraulic cylinder devices 8 and 9 are extended to their predetermined positions and the vehicle body is in a normal posture where further extension is restrained by stoppers (not shown), the oil pressure in the piping 7 rises rapidly as shown in Fig. 2. do. When the oil pressure reaches the set operating value _P2 of the oil pressure switch 10, the oil pressure switch 10 is activated, and the oil pump (not shown) in the oil pump device 1 stops rotating in response to the activation signal. , the vehicle height adjustment, that is, the vehicle body posture control is completed.

Effects of the invention As described above, according to the invention, in a hydraulic vehicle height adjustment device, the plunger is slidably fitted into the plunger case, the space inside the plunger case is divided into two chambers, and the plunger High-viscosity oil is used in the hydraulic system that communicates one chamber in the case with the oil pump device, and low-viscosity oil is used in the hydraulic system that communicates the other chamber with each hydraulic cylinder device for vehicle height adjustment. With an extremely simple configuration that only requires the use of a It is possible to efficiently operate each hydraulic cylinder device for vehicle height adjustment by minimizing the pressure loss of the vehicle, and it can bring about a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a vehicle height adjustment hydraulic circuit showing an embodiment of the present invention, and FIG. 2 is a diagram showing oil pressure changes during vehicle height adjustment. 1... Oil pump device, 2... Plunger case, 3... Plunger, 4... Left chamber, 5...
Right chamber, 6, 7... Piping, 8, 9... Hydraulic cylinder device, 10... Oil pressure switch, 1
1...Reservoir tank, 12...Check valve.

Claims (1)

[Scope of utility model registration request] A vehicle height adjustment mechanism consisting of hydraulic cylinder devices is incorporated into the front, rear, left and right wheel suspension sections, and oil is supplied to each of the hydraulic cylinder devices by the operation of an oil pump device to raise the vehicle height and bring the vehicle body into its normal position. In this hydraulic vehicle height adjustment device, a plunger is slidably fitted into a plunger case to divide the inside of the plunger case into two chambers, and one compartment formed in the plunger case is divided into two chambers. A hydraulic circuit is provided in which one chamber communicates with the oil pump device and the other chamber communicates with each hydraulic cylinder device, and the hydraulic circuit on the oil pump device side is filled with high-viscosity oil, and the hydraulic circuit of each hydraulic cylinder device is filled with low-viscosity oil. A hydraulic circuit for a hydraulic vehicle height adjustment device for an automobile, characterized in that each uses the following.