JP2005125940A - Hydraulic vehicle height adjustment mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a vehicle height adjustment mechanism enabling the vehicle height to be adjusted to an optional height and capable of being mounted to various types of vehicle by enabling the vehicle adjustment without mounting a position sensor or the like to the vehicle body side. <P>SOLUTION: The vehicle height adjustment mechanism is equipped with at least respective hydraulic cylinders 14 to 17 lifting and lowering the vehicle height by supplying and discharging hydraulic pressure, solenoid valves 18 to 21 opening/closing a passage supplying/discharging pressurized oil into respective hydraulic cylinders, a hermetically sealed reservoir tank 27, a pressure sensor 28 measuring air pressure in the reservoir tank 27, a solenoid valve 22 controlling an amount of pressurized oil discharged into the reservoir tank 27, a hydraulic pump 26 driven by an electric motor 25 and supplying the pressurized oil into the hydraulic cylinders 14 to 17, and an ECU 23 controlling the opening/closing of the valve of the solenoid valves 18 to 22, and controls the vehicle height position based on the air pressure measured at the reservoir 27. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle height adjusting device for a vehicle that adjusts the vehicle height using a liquid.

  The liquid pressure vehicle height adjustment mechanism includes, for example, a “vehicle height adjustment device for automobile” disclosed in Patent Document 1, a hydraulic cylinder for raising and lowering the vehicle height by supplying and discharging hydraulic pressure, and a hydraulic cylinder by driving an electric motor. Controls a hydraulic pump that supplies pressure oil to the vehicle, a solenoid valve that opens and closes a discharge passage for discharging the pressure oil in the hydraulic cylinder to the oil reservoir, and means for generating a vehicle height increase request signal and a vehicle height decrease request signal A vehicle for an automobile that lowers the vehicle height by operating the hydraulic pump for a predetermined time according to the vehicle height increase request signal and raising the vehicle height according to the device and opening the solenoid valve according to the vehicle height decrease request signal A high adjustment device is disclosed.

In addition, in the “brake hydraulic pressure control device in a vehicle having a vehicle height adjustment mechanism” in Patent Document 2, either one of a cylinder or a piston slidably fitted in the cylinder is fixed to a sprung member, The vehicle height is maintained at a predetermined height by controlling the supply and discharge of the pressure fluid to the cylinder by inserting a spring between the other of the cylinder or piston and the unsprung member. An adjustment mechanism is disclosed.
Japanese Patent Laid-Open No. 07-062212 Japanese Utility Model Publication No. 59-024651

However, since the vehicle height adjustment mechanism disclosed in Patent Document 1 can only adjust the vehicle height in two stages, Hi and Lo, the vehicle height cannot be adjusted according to the user's preference and purpose of use. There is a problem.
In addition, the vehicle height adjustment mechanism disclosed in Patent Document 2 needs to be attached to the vehicle body side in order to measure the vehicle height position, so that it may be difficult to install depending on the shape of the vehicle body attachment portion. Therefore, there is a problem that versatility is significantly reduced.

  The present invention is intended to solve the problems of such a conventional configuration, and enables the vehicle height to be adjusted to an arbitrary height according to the user's preference and purpose of use. It is another object of the present invention to realize a vehicle height adjustment mechanism having versatility that can be attached to various vehicle types by enabling the vehicle height adjustment without attaching a position sensor or the like to the vehicle body side body.

  According to a first aspect of the present invention, in a liquid pressure vehicle height adjustment mechanism for raising and lowering the vehicle height by supplying and discharging liquid, the pressure in a sealed reservoir tank used for storing the supplied and discharged liquid is controlled. Based on the pressure measuring means to measure and the amount of increase and decrease of the vehicle height for adjusting the vehicle height to a predetermined position, the pressure in the reservoir tank when the vehicle height is adjusted to the predetermined position is calculated Pressure estimating means that adjusts the pressure in the reservoir tank so that the pressure measured by the pressure measuring means matches the pressure calculated by the pressure estimating means. This is a liquid pressure vehicle height adjusting mechanism.

  According to the first aspect of the present invention, the pressure in the reservoir tank after the vehicle height is adjusted to a predetermined position by the pressure estimation unit is calculated, and the calculated pressure and the pressure measurement unit measure the pressure. By adjusting the pressure by the pressure control means so that the pressure in the reservoir tank matches, the vehicle height can be adjusted to a predetermined position.

  According to a second aspect of the present invention, in a liquid pressure vehicle height adjustment mechanism for raising and lowering the vehicle height by supplying and discharging liquid, the pressure in a sealed reservoir tank used for storing the supplied and discharged liquid is controlled. A pressure measuring means for measuring, a vehicle height position estimating means for calculating a vehicle height position based on the pressure measured by the pressure measuring means, and a vehicle height position calculated by the vehicle height position estimating means as a predetermined position. And a pressure control means for adjusting the pressure in the reservoir tank for adjustment.

  According to the invention described in claim 2, the vehicle height position estimating means calculates the vehicle height position based on the pressure in the reservoir tank measured by the pressure measuring means, and the vehicle height position and a predetermined vehicle height are calculated. It is possible to adjust the vehicle height to a predetermined position by adjusting the pressure by the pressure control means so that the position matches.

The invention according to claim 3 is the liquid pressure vehicle height adjusting mechanism according to claim 1 or 2, wherein the pressure measured by the pressure measuring means is a gas pressure in the reservoir tank.
The invention according to claim 4 is the liquid pressure vehicle height adjusting mechanism according to claim 1 or 2, wherein the pressure measured by the pressure measuring means is the liquid pressure in the reservoir tank.

According to the third and fourth aspects of the invention, the same effects as the first and second aspects of the invention can be achieved.
The invention according to claim 5 is calculated based on the temperature in the reservoir tank calculated based on the pressure measured by the pressure measuring means and the pressure measured by the pressure measuring means during the previous vehicle height adjustment. Temperature correction means for correcting an error from the temperature in the reservoir tank, and the pressure estimation means calculates the pressure with reference to the temperature corrected by the temperature correction means. The liquid pressure vehicle height adjustment mechanism according to claim 1.

  According to a fifth aspect of the present invention, when the temperature in the reservoir tank is calculated by the temperature correction means, and there is a temperature change in the reservoir tank with respect to the previous vehicle height adjustment, the temperature correction means By correcting the parameter depending on the temperature change used in the pressure estimating means, it is possible to correct the pressure in the reservoir tank for adjusting the vehicle height to a predetermined position. Even if the temperature of the vehicle changes, the vehicle height can be adjusted to a predetermined position.

  The invention according to claim 6 is calculated based on the temperature in the reservoir tank calculated based on the pressure measured by the pressure measuring means and the pressure measured by the pressure measuring means during the previous vehicle height adjustment. Temperature correction means for correcting an error from the temperature in the reservoir tank, and the position estimation means calculates the vehicle height position with reference to the temperature corrected by the temperature correction means. The liquid pressure vehicle height adjusting mechanism according to claim 2.

  According to the sixth aspect of the present invention, when the temperature in the reservoir tank is calculated by the temperature correction means, and there is a temperature change in the reservoir tank with respect to the previous vehicle height adjustment, the temperature correction means By correcting the parameter depending on the temperature change used in the position estimating means, it is possible to correct the vehicle height increase and decrease for adjusting the vehicle height to a predetermined position, Even if the temperature in the reservoir tank changes, the vehicle height can be adjusted to a predetermined position.

  According to a seventh aspect of the present invention, the pressure control means includes a first pressure adjusting means for adjusting the vehicle height of the front wheel portion, and a second pressure adjusting means for adjusting the vehicle height of the rear wheel portion. The vehicle height of the front wheel portion and the vehicle height of the rear wheel portion can be independently controlled by selectively switching between the first pressure adjusting means and the second pressure adjusting means. The liquid pressure vehicle height adjustment mechanism according to any one of claims 1 to 6, wherein the liquid pressure vehicle height adjustment mechanism is possible.

According to a seventh aspect of the present invention, the pressure control means includes a first adjustment means for adjusting the vehicle height of the front wheel portion, and a second pressure adjustment means for adjusting the vehicle height of the rear wheel portion. By selectively switching the vehicle height, the vehicle height of the front wheel portion and the vehicle height of the rear wheel portion can be adjusted independently.
The invention according to claim 8 is the liquid pressure vehicle height adjusting mechanism according to any one of claims 1 to 7, wherein the liquid is pressure oil.

  According to invention of Claim 8, there exists an effect similar to the invention of Claims 1-7 by using pressure oil for the said liquid.

  According to the present invention, the pressure obtained by the pressure measuring means for measuring the pressure in the sealed reservoir tank is controlled by the pressure control means to perform a predetermined vehicle height adjustment. For example, it is used as a pressure measuring means. Only one sensor is required, and it is not necessary to provide a separate sensor on the shock absorber or the vehicle body to obtain information on the vehicle height, thus realizing a vehicle height adjustment mechanism that does not depend on the shape of the vehicle body to be mounted. It becomes possible to do.

  Further, it is possible to realize a vehicle height adjustment mechanism that can adjust the vehicle height to an arbitrary height according to the user's preference and purpose of use.

Embodiments of the present invention will be described below with reference to FIGS.
FIG. 1 is a block diagram illustrating an outline of a configuration example of the embodiment.
The electronic control unit (ECU) 1 includes at least a pressure estimation unit 2, a temperature correction unit 3, and a pump / solenoid valve control unit 4, and controls the hydraulic cylinder by controlling the driving of the pump and the opening / closing of the solenoid valve. Control and adjust the vehicle height. In the figure, control necessity determination means 5 is further provided.

  Here, the processing of the electronic control unit (ECU) 1 is realized by a general information processing device. That is, a CPU for performing numerical calculation, a volatile memory for storing data necessary for calculation, an input device for inputting data, an output device for outputting data, and the present invention as necessary This is realized by an information processing apparatus including at least a non-volatile memory (for example, EEPROM) for storing a program, data, and the like necessary for realizing the above. In the above configuration, an external recording device for recording a program, data, and the like necessary for realizing the present invention may be further provided.

The pressure estimation means 2 calculates the pressure in a reservoir tank (not shown) when the vehicle height is adjusted based on, for example, an instruction from the vehicle height adjustment SW 6 installed in the vehicle.
The temperature correction means 3 estimates the temperature change based on the air pressure in a reservoir tank (not shown) measured using the pressure sensor 7 and the air pressure in the reservoir tank when the vehicle height was adjusted last time. Correction processing is performed for a parameter depending on the temperature change used.

The pump / solenoid valve control means 4 controls the pump / solenoid valve 8 by controlling the pump / solenoid valve 8 so that the target pressure notified from the pressure estimation means 2 matches the pressure notified from the pressure sensor 7. Supply and discharge pressure oil and adjust vehicle height.
In the figure, control necessity determining means 5 is further provided. The control necessity determining means 5 is, for example, a state in which the vehicle is running from the pressure SW10 that operates when unexpected hydraulic oil leaks from the hydraulic circuit, the vehicle speed sensor 11, and the side brake sensor 12 that measures whether the side brake is ON. If there is a travel signal indicating that the process is stopped, the pump / solenoid valve control means 4 is notified of the stop of the process. The pump / solenoid valve control means 4 stops the vehicle height adjustment process when the stop of the process is notified from the control necessity determination means 5. Further, the control necessity determination unit 5 can perform processing on the pump / solenoid valve control unit 4 when the side brake sensor 12 receives a stop signal indicating that the vehicle is stopped, for example. Notify that. When the pump / solenoid valve control means 4 is notified by the control necessity determination means 5 that the process can be executed, the pump height adjustment process becomes possible.

FIG. 2 is a block diagram showing an outline of the hydraulic control unit of the present embodiment.
For example, when a person who wants to adjust the vehicle height operates the vehicle height adjustment SW 6 installed in the vehicle, a vehicle height instruction signal is sent from the vehicle height adjustment SW 6 to the ECU 1. The ECU 1 calculates the pressure when adjusted to the vehicle height instructed from the vehicle height adjustment SW 6 by the pressure estimation means 2 and sets it as the target pressure. When the target pressure and the pressure in the tank (reservoir tank) 13 measured by the pressure sensor 7 do not match, the hydraulic pressure in the hydraulic circuit by the pump 8a and the electromagnetic for supplying and discharging the pressure oil to the hydraulic cylinder 9 The opening and closing of the valve 8b is controlled.

FIG. 3 is a diagram showing an outline of one embodiment of the present invention.
The hydraulic cylinders 14 to 17 attached to the front wheel right part, the front wheel left part, the rear wheel right part, and the rear wheel left part that raise and lower the vehicle height by supplying and discharging hydraulic pressure, and pressure oil in each hydraulic cylinder Solenoid valves 18 to 21 for opening and closing flow paths for supply and discharge, a sealed reservoir tank 27, a pressure sensor 28 for measuring the air pressure in the reservoir tank 27, and the reservoir tank 27 are discharged. A solenoid valve 22 for controlling the amount of pressure oil, a hydraulic pump 26 driven by an electric motor 25 to supply pressure oil to the hydraulic cylinders 14 to 17, the solenoid valves 18 to 21 and the solenoid valve 22 And an electronic control unit (ECU) 23 for controlling the opening and closing of the valves.

  In the hydraulic cylinder 14, when pressure oil is supplied to the oil chamber 14a through the valve of the solenoid valve 18, the inner tube 14b in the hydraulic cylinder 14 is pushed upward and lifts. The inner tube 14b is fixed to a vehicle body body (not shown) via a spring 14c, and the vehicle height is increased by raising the inner tube 14b.

  Further, when the solenoid valve 18 and the solenoid valve 22 are opened, the pressure oil in the oil chamber 14 a of the hydraulic cylinder 14 is discharged to the reservoir tank 27 through the solenoid valve 18 and the solenoid valve 22. As the pressure oil in the oil chamber 14a is discharged, the inner tube 14b is pushed downward by the weight of the vehicle body in the lower part of the drawing, and the vehicle height is lowered.

The hydraulic cylinders 15 to 17 are also raised and lowered according to the same principle.
The reservoir tank 27 stores the pressure oil supplied to the hydraulic cylinders 14 to 17 and stores the pressure oil discharged from the hydraulic cylinders 14 to 17. The reservoir tank 27 is divided by a partition in which an oil chamber for storing pressurized oil and an air chamber can swing. The reservoir tank 27 is provided with a pressure sensor 28 for measuring the pressure in the air chamber of the sealed reservoir tank 27.

The pressure value measured by the pressure sensor 28 is notified to an electronic control unit (ECU) 23.
The ECU 23 is connected to a control line from a vehicle body (not shown). Upon receiving an instruction signal for raising or lowering the vehicle body (including an upward and downward deviation amount) from the control line, a CPU (not shown) in the ECU 23 is provided. Of the reservoir tank 27 when the inner tubes of the hydraulic cylinders 14 to 17 are actually displaced by the indicated displacement amount from the displacement amount (for example, the displacement amount for raising the vehicle height is 1 cm) included in the instruction signal. Calculate air pressure. Then, the vehicle height is adjusted by controlling the solenoid valves 18 to 21, the solenoid valve 22, the electric motor 25, and the hydraulic pump 26 so that the calculated air pressure is obtained.

FIG. 4 shows a flowchart of control processing of the ECU for adjusting the vehicle height.
In step S1, it is checked whether the vehicle height adjustment operation has been performed. When there is no vehicle height adjustment operation, the vehicle height adjustment operation is waited. When the vehicle height adjustment operation is performed, the CPU in the ECU 23 reads the vehicle height value at the previous vehicle height adjustment stored in a non-volatile memory (for example, EPROM) (step S2).

  In step S3, the current air pressure (current air pressure) in the air chamber of the reservoir tank 27 is measured and read by the pressure sensor 28, and in step S4, the previous vehicle stored in a non-volatile memory (for example, EPROM). Reads the air pressure when adjusting high (air pressure at the previous adjustment).

  The CPU in the ECU 23 calculates the temperature change to be corrected using Equation 1 from the current air pressure measured in step S3 and the previous adjustment air pressure read in step S4 (step S5). Here, Equations 1 to 4 used in this embodiment are known methods derived from Boyle-Charles' law, and more specifically, “Fluid Dynamics (Correction 4th Edition)” Yasuyoshi Nakayama, Yoken Dou, described in p. 17 of 1989. In step S6, after correcting the maximum air chamber volume value by equation 2 based on the temperature change calculated in step S5, the vehicle height adjustment amount instructed by the vehicle height adjustment operation (step S1) using equation 3. Is converted into the air pressure adjustment amount of the reservoir tank 27, and the target air pressure after the vehicle height adjustment is calculated (step S7).

Here, V ₀ [mm ³ ] is the maximum air chamber volume in the reservoir tank 27, P ₀ [MPa] is the minimum air pressure in the reservoir tank 27, P _max [MPa] is the maximum pressure in the reservoir tank 27, L _F [mm] is the stroke of the front wheel hydraulic cylinder, L _R [mm] is the stroke of the rear wheel hydraulic cylinder, d _c [mm] is the cylinder diameter in the hydraulic cylinder, and T _G [° C.] is in the reservoir tank 27 Air chamber temperature, P _n [MPa] is the air pressure in the n-th reservoir tank 27, x _n [mm] is the n-th cylinder stroke amount, T _G ′ [° C.] is the air chamber temperature after temperature change, Pn ′ [MPa] indicates the air pressure in the n-th reservoir tank 27 after the temperature change (the n-th stage refers to the nth stage obtained by equally dividing the total cylinder stroke by a predetermined length). Say length).

Further, by further providing a temperature sensor in the configuration of FIG. 1, more accurate vehicle height control can be performed. That is, the temperature difference between the current temperature and the temperature at the time of the previous vehicle height adjustment is calculated based on the temperature information obtained directly from the temperature sensor without calculating T _G ′ by Equation 1, and the calculated temperature difference and By calculating the difference between the current atmospheric pressure and the atmospheric pressure at the previous adjustment from the pressure difference between Pn and Pn ′, the target air pressure value can be determined more precisely. By adopting such a configuration, it is possible to avoid being affected by changes in air pressure when the altitude difference is large.

  In step S8, it is checked whether the vehicle height adjustment target is the front wheel hydraulic cylinder or the rear wheel hydraulic cylinder. If the vehicle height adjustment target is the front wheel hydraulic cylinder, the process proceeds to step S9. The process proceeds, and it is further checked whether it is an ascending instruction or a descending instruction.

In step S9, when it is an instruction to raise the vehicle height, the CPU opens the solenoid valve 18 and the solenoid valve 19, and simultaneously operates the electric motor 25 to supply pressure oil to the hydraulic cylinder 14 and the hydraulic pressure. Supply to the cylinder 15 (step S10).
In step S11, the CPU acquires the air pressure in the reservoir tank 27 from the pressure sensor 28, and compares the acquired current air pressure value with the target air pressure value calculated in step S7. If the current air pressure value and the target air pressure value do not match, the process of step S11 is repeated until they match.

  In step S11, when the current air pressure value of the reservoir tank 27 acquired from the pressure sensor 28 matches the target air pressure value, the processing of the CPU proceeds to step S12, and the valves of the solenoid valve 18 and the solenoid valve 19 are turned on. Simultaneously with the closed state, the electric motor 25 is stopped to stop the supply of pressure oil to the hydraulic cylinder 14 and the hydraulic cylinder 15.

In step S12, when the process of supplying the hydraulic oil to the hydraulic cylinder is completed, the current air pressure value of the reservoir tank 27 is recorded in a nonvolatile memory (for example, EEPROM), the process proceeds to step S1, and the vehicle height adjustment operation is performed. Waiting.
In step S9, when it is a vehicle height lowering instruction, the CPU opens the solenoid valve 18, the solenoid valve 19 and the solenoid valve 22, and stores the hydraulic oil in the hydraulic cylinder 14 and the hydraulic cylinder 15 as reservoirs. It discharges to the tank 27 (step S14).

  In step S15, the CPU acquires the air pressure in the reservoir tank 27 from the pressure sensor 28, and compares the acquired current air pressure value with the target air pressure value calculated in step S7. If the current air pressure value and the target air pressure value do not match, the process of step S15 is repeated until they match.

  In step S15, when the current air pressure value of the reservoir tank 27 acquired from the pressure sensor 28 matches the target air pressure value, the processing of the CPU proceeds to step S16, and the solenoid valve 18, the solenoid valve 19, and the solenoid valve. The valve 22 is closed, and the process of discharging the hydraulic oil from the hydraulic cylinder 14 and the hydraulic cylinder 15 is stopped.

In step S16, when the supply process of the pressure oil to the hydraulic cylinder is completed, the current air pressure value of the reservoir tank 27 is recorded in a non-volatile memory (for example, EEPROM), the process proceeds to step S1, and the vehicle height adjustment operation is performed. Waiting.
In step S8, when the vehicle height adjustment target is the hydraulic cylinder of the rear wheel part, the process proceeds to step S17, and it is further checked whether it is an ascending instruction or a descending instruction.

  In step S17, when it is an instruction to increase the vehicle height, the CPU opens the solenoid valve 20 and the solenoid valve 21, and simultaneously operates the electric motor 25 to supply pressure oil to the hydraulic cylinder 16 and the hydraulic pressure. Supply to the cylinder 17 (step S18).

  In step S19, the CPU acquires the air pressure in the reservoir tank 27 from the pressure sensor 28, and compares the acquired current air pressure value with the target air pressure value calculated in step S7. If the current air pressure value and the target air pressure value do not match, the process of step S19 is repeated until they match.

  In step S19, when the current air pressure value of the reservoir tank 27 acquired from the pressure sensor 28 matches the target air pressure value, the processing of the CPU proceeds to step S20, and the valves of the solenoid valve 20 and the solenoid valve 21 are turned on. Simultaneously with the closed state, the electric motor 25 is stopped to stop the supply of pressure oil to the hydraulic cylinder 16 and the hydraulic cylinder 17.

In step S20, when the process of supplying the hydraulic oil to the hydraulic cylinder is completed, the current air pressure value of the reservoir tank 27 is recorded in a non-volatile memory (for example, EEPROM), the process proceeds to step S1, and the vehicle height adjustment operation is performed. Waiting.
In step S17, when it is a vehicle height lowering instruction, the CPU opens the solenoid valve 20, the solenoid valve 21, and the solenoid valve 22, and stores the hydraulic cylinder 16 and the pressure oil in the hydraulic cylinder 17 as reservoirs. It discharges to the tank 27 (step S21).

  In step S22, the CPU acquires the air pressure in the reservoir tank 27 from the pressure sensor 28, and compares the acquired current air pressure value with the target air pressure value calculated in step S7. If the current air pressure value and the target air pressure value do not match, the process of step S22 is repeated until they match.

  In step S22, when the current air pressure value of the reservoir tank 27 acquired from the pressure sensor 28 matches the target air pressure value, the processing of the CPU proceeds to step S23, and the solenoid valve 20, the solenoid valve 21, and the solenoid valve. The valve 22 is closed, and the discharge of the pressure oil from the hydraulic cylinder 16 and the hydraulic cylinder 17 is stopped.

In step S23, when the process of supplying the hydraulic oil to the hydraulic cylinder is completed, the current air pressure value of the reservoir tank 27 is recorded in a non-volatile memory (for example, EEPROM), and the process proceeds to step S1 to adjust the vehicle height. Waiting.
As described above, according to the present invention, the amount of increase and decrease of the vehicle height can be obtained from the air pressure in the reservoir tank 27. Therefore, the vehicle height can be adjusted only by providing one sensor for measuring the air pressure in the reservoir tank 27. The mechanism can be realized, and the vehicle height can be easily adjusted to an arbitrary height by the control of the ECU shown in FIG.

In addition, there is no need to provide a separate sensor (for example, a position sensor for measuring the vehicle height position) on the shock absorber or the vehicle body, so there is no restriction on the shape of the mounted vehicle body, and a highly versatile vehicle height adjustment mechanism is provided. It can be realized.
In the above description, in the embodiment of the present invention, the hydraulic circuit shown in FIG. 3 is used for raising and lowering the hydraulic cylinders 14 to 17, but this is not restrictive. Any circuit configuration may be used as long as the hydraulic oil can be supplied to or discharged from the hydraulic cylinders provided at the front wheel left part and the front wheel right part, and the rear wheel left part and the rear wheel right part.

In this embodiment, a reservoir tank in which an air chamber is provided together with an oil chamber is used in the sealed reservoir tank 27. However, a gas (for example, nitrogen gas) may be used instead of air. Good. Further, the pressure may be a hydraulic pressure.
In FIG. 4, for example, in step S7, the target air pressure in the reservoir tank 27 adjusted to a predetermined vehicle height position is calculated, and the air pressure in the reservoir tank 27 is controlled so as to coincide with the target air pressure in steps S8 to S23. However, the current vehicle height position may be calculated from the air pressure in the reservoir tank 27, and the vehicle height position may be controlled in steps S8 to S23 so as to coincide with the predetermined vehicle height position.

  For example, in step S1 of FIG. 4, it is checked whether the vehicle height adjustment operation has been performed. When there is no vehicle height adjustment operation, the vehicle height adjustment operation is waited. When the vehicle height adjustment operation is performed, the CPU in the ECU 23 reads the vehicle height value at the previous vehicle height adjustment stored in a non-volatile memory (for example, EPROM) (step S2).

  In step S3, the current air pressure (current air pressure) in the air chamber of the reservoir tank 27 is measured and read by the pressure sensor 28, and in step S4, the previous vehicle stored in a non-volatile memory (for example, EPROM). Reads the air pressure when adjusting high (air pressure at the previous adjustment).

The CPU in the ECU 23 calculates the temperature change to be corrected using Equation 1 from the current air pressure measured in step S3 and the previous adjustment air pressure read in step S4 (step S5).
In step S7, the target pressure is calculated by Equation 3 based on the temperature change calculated in step S5 and the vehicle height adjustment amount calculated in step S6.

  In step S8, it is checked whether the vehicle height adjustment target is the front wheel hydraulic cylinder or the rear wheel hydraulic cylinder. If the vehicle height adjustment target is the front wheel hydraulic cylinder, the process proceeds to step S9. The process proceeds, and it is further checked whether it is an ascending instruction or a descending instruction.

In step S9, when it is an instruction to raise the vehicle height, the CPU opens the solenoid valve 18 and the solenoid valve 19, and simultaneously operates the electric motor 25 to supply pressure oil to the hydraulic cylinder 14 and the hydraulic pressure. Supply to the cylinder 15 (step S10).
Further, in step S11, the CPU calculates the air pressure value in the reservoir tank 27 obtained from the pressure sensor 28 by using the expression 4 and the current vehicle height position amount (for example, the unit is mm, and the outer case and the inner tube 14b). Convert to total length x). The current vehicle height position is compared with the target vehicle height position value instructed in step S1. If the current vehicle height position and the target vehicle height position do not match, the process of step S11 is repeated until they match.

  In step S11, if the current vehicle height position matches the target vehicle height position, the processing of the CPU proceeds to step S12, and the valves of the solenoid valve 18 and the solenoid valve 19 are closed, and at the same time, the electric motor 25 is stopped to stop the pressure oil supply process to the hydraulic cylinder 14 and the hydraulic cylinder 15.

In step S12, when the process of supplying the hydraulic oil to the hydraulic cylinder is completed, the current air pressure value of the reservoir tank 27 is recorded in a nonvolatile memory (for example, EEPROM), the process proceeds to step S1, and the vehicle height adjustment operation is performed. Waiting.
Similarly, the lowering process of the front wheel part and the raising and lowering process of the rear wheel part can be performed by the processes of step S14 to step S23.

  In the embodiment described above, the vehicle height adjustment mechanism is realized by pressure oil, but is not limited to pressure oil. The present invention can realize the vehicle height adjusting mechanism shown in the embodiment by using other liquids.

It is a block diagram which shows the outline | summary of the structural example of a present Example. It is a block diagram which shows the outline | summary of the hydraulic control part of a present Example. It is a figure which shows the outline | summary of the example of embodiment. It is a flowchart which shows the control processing of ECU for adjusting the vehicle height of the example of embodiment.

Explanation of symbols

1 ... Electronic control unit (ECU)
2 ... Pressure estimation means 3 ... Temperature correction means 4 ... Pump / solenoid valve control means 5 ... Control necessity determination means 6 ... Vehicle height adjustment SW
7 ... Pressure sensor 8 ... Pump / solenoid valve 8a ... Pump 8b ... Solenoid valve 9 ... Hydraulic cylinder 10 ... Pressure SW
11 ... Vehicle height sensor 12 ... Side brake sensor 13 ... Tank (reservoir tank)
14 ... Hydraulic cylinder 14a on the right side of the front wheel ... Oil chamber 14b ... Inner tube 14c ... Spring 15 ... Hydraulic cylinder 16 on the left side of the front wheel ... Hydraulic cylinder 17 on the right side of the rear wheel ..Left wheel hydraulic cylinder 18-22 ... Solenoid valve 23 ... Electronic control unit (ECU)
24 ... Pressure reducing valve 25 ... Electric motor 26 ... Hydraulic pump 27 ... Reservoir tank 28 ... Pressure sensor 29-33 ... Check valve

Claims (8)

In the liquid pressure vehicle height adjustment mechanism that raises and lowers the vehicle height by supplying and discharging liquid,
Pressure measuring means for measuring the pressure in a sealed reservoir tank used for storing the supplied and discharged liquid;
Pressure estimating means for calculating the pressure in the reservoir tank when the vehicle height is adjusted to the predetermined position based on the amount of increase and decrease of the vehicle height for adjusting the vehicle height to a predetermined position;
Pressure control means for adjusting the pressure in the reservoir tank so that the pressure measured by the pressure measuring means and the pressure calculated by the pressure estimating means match;
A liquid pressure vehicle height adjustment mechanism comprising: In the liquid pressure vehicle height adjustment mechanism that raises and lowers the vehicle height by supplying and discharging liquid,
Pressure measuring means for measuring the pressure in a sealed reservoir tank used for storing the liquid to be supplied and discharged;
Vehicle height position estimating means for calculating the vehicle height position based on the pressure measured by the pressure measuring means;
Pressure control means for adjusting the pressure in the reservoir tank in order to adjust the vehicle height position calculated by the vehicle height position estimating means to a predetermined position;
A liquid pressure vehicle height adjustment mechanism comprising:   3. The liquid pressure vehicle height adjustment mechanism according to claim 1, wherein the pressure measured by the pressure measuring means is a gas pressure in the reservoir tank.   3. The liquid pressure vehicle height adjustment mechanism according to claim 1, wherein the pressure measured by the pressure measuring means is a liquid pressure in the reservoir tank. The temperature in the reservoir tank calculated based on the pressure measured by the pressure measuring means and the temperature in the reservoir tank calculated based on the pressure measured by the pressure measuring means during the previous vehicle height adjustment. Having temperature correction means for correcting the error;
2. The liquid pressure vehicle height adjustment mechanism according to claim 1, wherein the pressure estimation unit calculates the pressure with reference to the temperature corrected by the temperature correction unit. The temperature in the reservoir tank calculated based on the pressure measured by the pressure measuring means and the temperature in the reservoir tank calculated based on the pressure measured by the pressure measuring means during the previous vehicle height adjustment. Having temperature correction means for correcting the error;
3. The liquid pressure vehicle height adjustment mechanism according to claim 2, wherein the position estimation unit calculates the vehicle height position with reference to the temperature corrected by the temperature correction unit. The pressure control means includes first pressure adjusting means for adjusting the vehicle height of the front wheel portion,
A second pressure adjusting means for adjusting the vehicle height of the rear wheel portion;
Further comprising
By selectively switching between the first pressure adjusting means and the second pressure adjusting means, the vehicle height of the front wheel portion and the vehicle height of the rear wheel portion can be controlled independently. The liquid pressure vehicle height adjustment mechanism according to any one of claims 1 to 6. The liquid pressure vehicle height adjustment mechanism according to any one of claims 1 to 7, wherein the liquid is pressure oil.

Images