JP4380554B2 - Vehicle height adjustment device - Google Patents

Description

  The present invention relates to a vehicle height adjusting device including a fluid cylinder and an accumulator connected to the fluid cylinder.

Patent Documents 1 to 4 describe a vehicle height adjusting device including a fluid cylinder and an accumulator connected to the fluid cylinder. Among them, in Patent Documents 1 to 3, hydraulic fluid is used as a fluid, one of the two accumulators and a hydraulic cylinder are connected via a spring constant switching valve, and the opening and closing control of the spring constant switching valve is performed. It is described that switching can be made between a state where two accumulators are connected to the hydraulic cylinder (a state where the spring constant is small) and a state where one accumulator is connected (a state where the spring constant is large). In the vehicle height adjusting device described in Patent Document 1, when the vehicle height is vibrated by road surface irregularities or the like, the vehicle height is in the “vehicle height high region” and the vehicle height is in the “vehicle height low region”. The spring constant is set to a large state, and the spring constant is set to a small state when the spring constant is in the “neutral vehicle height region”. Further, in the vehicle height adjusting devices described in Patent Documents 2 and 3, when the vehicle height is vibrated by road surface unevenness or the like, the actual vehicle height is changed when the spring constant switching valve is switched to the closed state. When the vehicle height is almost the same as when the vehicle is switched to the closed state, the vehicle is switched to the open state. As a result, hydraulic pressure pulsation during switching of the spring constant switching valve is suppressed.
JP-A 63-49512 JP-A 63-78806 Japanese Patent Laid-Open No. Sho 63-130419 JP-A-11-198625

  SUMMARY OF THE INVENTION An object of the present invention is to increase the speed when reducing the vehicle height and to moderate the change in the change speed of the vehicle height in the vehicle height adjusting device including the fluid cylinder and the accumulator described above. .

Means and effects for solving the problems

The vehicle height adjusting device according to claim 1 includes: (a) a fluid cylinder provided between the wheel holding device and the vehicle body corresponding to a vehicle wheel; and (b) fluid flowing into the fluid cylinder. A fluid control device capable of adjusting a vehicle height between a wheel holding device for the wheel and a portion of the vehicle body on which the fluid cylinder is provided, and (c) connected to the fluid cylinder. One or more accumulators; and (d) the fluid control device causes the fluid to flow out of the fluid cylinder, thereby reducing the vehicle height corresponding to the fluid cylinder at a time. from at least one of the outflow of fluid to a vehicle height adjusting device comprising an accumulator flow control device blocking and (x) the at least one accumulator, the fluid out of the accumulator (Y) the accumulator flow control device is provided between the at least one accumulator and the fluid passage, respectively, and at least At least one electromagnetic control valve that can be switched between a communication state to be communicated and a shut-off state to be shut off; and (ii) when a first set time has elapsed from the start of the vehicle height reduction by the fluid control device; A shut-off state switching unit that switches the at least one electromagnetic control valve from an open state to a closed state in any one of a case where the amount of decrease in vehicle height from the start of height decrease is equal to or greater than a first set decrease amount; And a solenoid valve controller provided .

In the present vehicle height adjusting device, the vehicle height is reduced by causing the fluid to flow out of the fluid cylinder, but at one time when the vehicle height is decreased, of the one or more accumulators connected to the fluid cylinder. Outflow of fluid from at least one is prevented.
When the fluid cylinder and the accumulator are in communication with each other, the fluid is often discharged from the accumulator when the fluid is discharged from the fluid cylinder.
For example, the fluid cylinder is often provided in parallel with the suspension spring between the wheel holding device and the vehicle body. In this case, if the fluid flows out of the fluid cylinder and the relative height of the vehicle body with respect to the wheel holding device is lowered, the amount of elastic deformation of the suspension spring increases, so the load received by the suspension spring against the load received by the fluid cylinder The ratio increases. The fluid cylinder receives less load and lowers pressure. Therefore, when the relative height is lowered, the fluid is also discharged from the accumulator.
On the other hand, if the fluid cylinder is not provided in parallel with the suspension spring and the relative heights of all the front, rear, left and right wheels of the vehicle are similarly lowered, the load applied to each wheel does not change. The pressure of no change. In this case, no fluid is allowed to flow out of the accumulator. However, for example, if the relative height of one of the front, rear, left and right wheels is lowered, the load applied to the wheel is reduced, and the pressure of the fluid cylinder corresponding to the wheel is lowered. In this case, the fluid is also discharged from the accumulator.

Therefore, when the vehicle height is reduced, if the outflow of the fluid from the at least one accumulator is prevented, the amount of the fluid discharged from the accumulator connected to the fluid cylinder can be reduced. The time required to reduce the vehicle height to the target vehicle height can be shortened compared to the case where fluid flow from all connected accumulators is allowed, and the vehicle height reduction speed should be increased. Can do.
In addition, when the vehicle height is reduced at one time, the vehicle height reduction speed is smaller than when the vehicle height is reduced over the entire period, but the change in the vehicle height change speed can be moderated.
For example, during a period in which the vehicle height is reduced, a period during which the outflow is permitted at least one of the set time from the start of the decrease in the vehicle height and the set time before the end of the decrease in the vehicle height, and excluding at least one of them If the vehicle is prevented from flowing out, it is possible to suppress a rapid change in the change speed of the vehicle height at the start or end of the decrease in the vehicle height while increasing the decrease speed of the vehicle height.
Further, the vehicle body is vibrated due to a pressure difference between the accumulator and the fluid cylinder at the time of switching between a state in which the fluid outflow from the accumulator is prevented (outflow prevention state) and an allowable state (outflow permission state). Sometimes. Therefore, before the vehicle height adjustment is started, it is switched in consideration of whether the accumulator is in a fluid outflow prevention state or whether it is scheduled to enter the outflow prevention state after the vehicle height adjustment is completed. Is desirable. For example, if the vehicle is in the outflow prevention state before the vehicle height adjustment is started, switching to the outflow allowed state at the start of the vehicle height adjustment causes the vibration and vehicle height caused by the difference between the accumulator pressure and the fluid cylinder pressure. There is a risk that a large change may occur due to a change in the vehicle height due to the adjustment. On the other hand, if the vehicle height is started to be reduced after the vehicle height is reduced, the change in the vehicle height can be dispersed.
Thus, if the change in the change speed of the vehicle height can be reduced, the occupant's feeling can be improved when the occupant is present in the vehicle. In addition, when there is no occupant, it is possible to avoid sudden movement of the vehicle body or to reduce the contact noise even if the vehicle height is reduced until the vehicle body contacts the stopper, You can avoid surprised people around you.

Note that the fluid cylinder may use hydraulic fluid or may use air.
Further, the number of accumulators connected to the fluid cylinder may be one or more than two, and the accumulator that prevents the outflow of fluid when the vehicle height is reduced is connected to the fluid cylinder. It may be all of the accumulators or some of them.
Furthermore, the fluid control device is a device that causes fluid to flow into or out of the fluid cylinder, and includes, for example, a fluid supply device that supplies fluid to the fluid cylinder, a fluid outlet device that causes fluid to flow out of the fluid cylinder, and the like. . The fluid supply device includes a high-pressure source (for example, a pump, an accumulator, etc.), an inflow control valve, etc., and the fluid outflow device is a low-pressure source (in the case of air or a low-pressure tank such as a reservoir), Includes outflow control valve. The inflow control valve and the outflow control valve may be separate or common.

The vehicle height adjusting device according to claim 4 includes: (a) a fluid cylinder provided between the wheel holding device and the vehicle body corresponding to a vehicle wheel; and (b) flowing fluid into the fluid cylinder. A fluid control device capable of adjusting a vehicle height between a wheel holding device for the wheel and a portion of the vehicle body on which the fluid cylinder is provided, and (c) connected to the fluid cylinder. One or more accumulators; and (d) a reduction in the vehicle height when the fluid control device causes the fluid to flow into the fluid cylinder to reduce the vehicle height corresponding to the fluid cylinder . Either after the first set time has elapsed since the start, or after the vehicle height reduction amount from the start of vehicle height reduction has become equal to or greater than the first set reduction amount, One or more accumulation It is intended to include the suppressing accumulator flow control the flow of fluid from.
The suppression of fluid outflow is a state in which the amount of fluid discharged from the accumulator is reduced when the fluid cylinder fluid pressure, the amount of change in the relative height of the wheel holding device and the vehicle body are the same, for example, For example, blocking outflow and reducing the flow path area of the connecting passage between the accumulator and the fluid cylinder are applicable.
Even if the accumulator flow control device suppresses the outflow of fluid for all of the one or more accumulators connected to one fluid cylinder, the outflow of fluid from at least one accumulator of the one or more accumulators It may be a thing which suppresses.
For example, when two accumulators are connected to one fluid cylinder, the outflow of fluid from two accumulators is suppressed at the “one time”, the outflow of fluid from one accumulator is suppressed, For example, the accumulator with the smaller spring constant can be communicated at the “other period”, and the accumulator with the larger spring constant can be communicated at the “one period”.

Patentable invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter sometimes referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, and inventions of other concepts) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the set of components constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

Of the following items, items (3) and (5) correspond to claims 1 and 2, and item (7) corresponds to claim 3. Further, the part in which the feature of the item (3) is adopted in the item (8) corresponds to claim 4.

(1) a fluid cylinder provided between the wheel holding device and the vehicle body corresponding to the vehicle wheel;
A fluid control device capable of adjusting a vehicle height between a wheel holding device for the wheel and a portion of the vehicle body where the fluid cylinder is provided by allowing fluid to flow into or out of the fluid cylinder;
One or more accumulators connected to the fluid cylinder;
Fluid from at least one of the one or more accumulators at a time when the fluid control device causes the fluid to flow out of the fluid cylinder to reduce the vehicle height corresponding to the fluid cylinder. A vehicle height adjusting device comprising: an accumulator distribution control device for preventing the outflow of the vehicle.
(2) The at least one accumulator is connected to a fluid passage that connects the fluid cylinder and the fluid control device, and the accumulator flow control device is provided between the at least one accumulator and the fluid passage, respectively. And at least one electromagnetic control valve that can be switched between a communication state for communicating them and a cutoff state for blocking them, and at least one electromagnetic control valve at a time when the vehicle height is reduced. Thus, the vehicle height adjusting device according to item (1), further including an electromagnetic valve control unit that prevents outflow of fluid from the at least one accumulator.
The at least one accumulator is connected to a fluid passage connecting the fluid cylinder and the fluid control device via an electromagnetic control valve. The electromagnetic control valve may be an electromagnetic on-off valve that can be switched between a state in which the accumulator and the fluid passage are communicated with each other or a state in which the accumulator and the fluid passage are cut off, or a linear control valve or a variable throttle that can control the flow area in the communication state it can. In any case, the electromagnetic control valve is shut off at a time when the vehicle height is reduced, and the fluid is prevented from flowing out from the accumulator to the fluid passage. Therefore, the outflow rate of the fluid flowing out from the fluid cylinder through the fluid passage can be increased, and the reduction speed of the vehicle height can be increased.
(3) When the first set time has elapsed from the start of the decrease in the vehicle height by the fluid control device, and when the solenoid valve control unit has a decrease in the vehicle height from the start of the decrease in the vehicle height, The vehicle height adjusting device according to (2), further including a shut-off state switching unit that switches the at least one electromagnetic control valve from a communication state to a shut-off state in any one of cases where the set decrease amount is exceeded.
In the vehicle height adjusting device described in this section, when the first set time elapses after the control for reducing the vehicle height is started until the first set time elapses, the first set time elapses. In addition, the communication state is switched to the cutoff state. At the beginning of the decrease in vehicle height, the vehicle height decrease speed is set to a small state, but thereafter, the vehicle height decrease speed is set to a large state. Thus, if the reduction speed is set to a small state at the beginning of the vehicle height reduction, a sudden change in the vehicle height reduction speed at the start of the vehicle height adjustment can be avoided. In addition, after that, the time required for reducing the vehicle height to the target vehicle height can be shortened by setting the reduction speed to a large state.
If the first set time is too long, the time required to reduce to the target vehicle height will be long, and if it is too short, the effect of reducing the reduction speed cannot be obtained sufficiently. Also, based on the vehicle height at the start of vehicle height reduction control and the target vehicle height, the vehicle height is reduced to the target vehicle height in each of the states where fluid outflow from the accumulator is blocked and allowed. You can see how long it takes to decrease. Based on the above circumstances, the first set time is set.
In this case, the electromagnetic control valve is either in the case where the first set time has elapsed since the start of the reduction control, or in the case where the reduction amount of the vehicle height from the start of the reduction control is equal to or more than the first set reduction amount. The switch is switched to the shut-off state. That is, switching may be performed based on time or based on vehicle height, and the first set decrease amount may be the decrease amount of the vehicle after the first set time has elapsed.
In the vehicle height reduction control, when it is known that the vehicle height is reduced from the standard height to a predetermined target height, the first set time and the first set decrease amount are set in advance. You can also keep it.
(4) The electromagnetic valve control unit is configured such that the vehicle height reduction amount from the start of the vehicle height reduction by the fluid control device is 1 / n or more of a value obtained by subtracting the target vehicle height from the vehicle height at that time. The vehicle height adjusting device according to (2) or (3), further including a shut-off state switching unit that switches the at least one electromagnetic control valve from the communication state to the shut-off state when the state is reached.
The number of n is preferably 2 or more, 4 or more, 7 or more, 10 or more, 20 or more, and is preferably 5 or less, 8 or less, 15 or less, or 25 or less.
When the electromagnetic control valve is switched based on time, the switching time can be the time required for the vehicle height reduction amount to reach the set reduction amount described above.
(5) When the second set time that is longer than the first set time has elapsed since the start of the vehicle height reduction by the fluid control device, the electromagnetic valve control unit and the vehicle from the start of the vehicle height reduction start. The at least one electromagnetic control valve is switched from the shut-off state to the communication state when one of the case where the high reduction amount is equal to or greater than the second set reduction amount greater than the first set reduction amount is satisfied. The vehicle height adjusting device according to any one of (3) or (4), including a communication state switching unit.
If the electromagnetic control valve is switched from the shut-off state to the communication state before the control for reducing the vehicle height is completed, the vehicle height reduction speed before the control for reducing the vehicle height can be reduced, The change in the vehicle height reduction speed at the end of the vehicle height adjustment can be moderated.
If the second set time is too short, the time required for the vehicle height adjustment becomes long, and if it is too long, the effect of providing a period for reducing the reduction speed cannot be sufficiently obtained. Therefore, it is desirable to set the second set time in consideration of these and the time required to reach the above-described target vehicle height.
As in the case where the first set time and the first set decrease amount are set, the second set time and the second set decrease amount can also be determined in advance.
(6) The electromagnetic valve control unit is configured such that the vehicle height reduction amount from the start of the vehicle height reduction by the fluid control device is 1 / m or more of a difference obtained by subtracting the target vehicle height from the vehicle height at that time. The vehicle height adjusting device according to any one of (3) to (5), further including a communication state switching unit that switches the at least one electromagnetic control valve from a shut-off state to a communication state when the state is reached.
m is a number smaller than n. For example, m is desirably 2 or less, 1.5 or less, 1.2 or less, or 1.1 or less, and desirably 1.05 or more, 1.25 or more, and 1.7 or more.

(7) Two accumulators are connected to the fluid cylinder, one of which has a smaller spring constant than the other, and one of the accumulators is connected to the fluid passage via an electromagnetic control valve. The section includes a spring constant switching control section in which the spring constant is set to a large state by switching the electromagnetic control valve from the open state to the closed state at a time when the control for reducing the vehicle height is performed. The vehicle height adjusting device according to any one of items 6).
In the accumulator, fluid is supplied and stored with the elastic deformation of the elastic body. In the state where the fluid is stored, the pressure of the fluid has a magnitude corresponding to the elastic force of the elastic body. In the vehicle height adjusting device described in this section, one of the accumulators has a smaller spring constant of the elastic body than the other accumulator.
When the pressure of the fluid stored in the accumulator is reduced by the same amount between the accumulator having a large spring constant and the accumulator having a small spring constant, the amount of fluid flowing out from the accumulator having a small spring constant increases. Therefore, if the fluid outflow from the accumulator with the smaller spring constant is suppressed, the time required for the vehicle height adjustment can be effectively shortened.

(8) a fluid cylinder provided between the wheel holding device and the vehicle body corresponding to the vehicle wheel;
A fluid control device capable of adjusting a vehicle height between a wheel holding device for the wheel and a portion of the vehicle body where the fluid cylinder is provided by allowing fluid to flow into or out of the fluid cylinder;
One or more accumulators connected to the fluid cylinder;
When the fluid control device causes the fluid to flow out to the fluid cylinder, the fluid flow from the one or more accumulators from one time to another when the vehicle height corresponding to the fluid cylinder is reduced is reduced. A vehicle height adjusting device comprising: an accumulator distribution control device for suppressing the vehicle.
The technical features described in the above items (1) to (7) can be employed in the vehicle height adjusting device described in this item.
(9) a fluid cylinder provided between the wheel holding device and the vehicle body corresponding to the vehicle wheel;
A fluid control device capable of adjusting a vehicle height between a wheel holding device for the wheel and a portion of the vehicle body where the fluid cylinder is provided by allowing fluid to flow into or out of the fluid cylinder;
One or more accumulators connected to the fluid cylinder;
Fluid to at least one of the one or more accumulators at a time when the fluid control device causes fluid to flow into the fluid cylinder to increase the vehicle height corresponding to the fluid cylinder. A vehicle height adjusting device comprising: an accumulator distribution control device for preventing inflow of the vehicle.
The technical features described in the above items (1) to (8) can be similarly applied when increasing the vehicle height.

Hereinafter, a vehicle height adjusting device according to an embodiment of the present invention will be described.
A suspension cylinder 24 as a fluid cylinder is provided with a suspension spring (not shown) between the wheel holding device 20 that holds the wheel and the vehicle body 22 corresponding to each of the front and rear wheels 10 to 16 of the vehicle. Each of the suspension cylinders 24 includes a housing 30 and a piston 32 slidably fitted in the housing 30, and the housing 30 is partitioned into two liquid chambers 36 and 38 by the piston 32. The piston 32 is provided with a communication passage 40 having a throttle communicating the two liquid chambers 36 and 38.
In the present embodiment, the piston rod 34 of the piston 32 is connected to the wheel holding device 20 so as not to be relatively movable in the vertical direction and to be relatively rotatable, and the housing 30 is not relatively movable in the vertical direction and is relatively rotatable. Connected to In addition, a hydraulic fluid is used as the fluid, and a shock absorber is used as the suspension cylinder 24, whereby a damping force corresponding to the moving speed of the piston 32 is generated.

In each of the suspension cylinders 24 corresponding to the wheels 10 to 16, a fluid control device 58 is connected to the liquid chamber 36 via individual passages 50 to 56 as fluid passages.
The fluid control device 58 includes a control pressure passage 60 connected to the individual passages 50 to 56, a pump 70 connected to the control pressure passage 60, a pressure accumulator 74, a reservoir 76, and the like. The pump 70 is operated by driving a pump motor 72, and pumps up the hydraulic fluid from the reservoir 76 and discharges it. The hydraulic fluid discharged from the pump 70 is stored in the pressure accumulator 74 in a pressurized state. The pump motor 72 is operated when there is a request to increase the vehicle height, when the pressure of the accumulator 74 for pressure accumulation is increased, or the like. The pressure accumulator 74 is connected to the control pressure passage 60 via a normally closed pressure accumulation control valve 78.
A check valve 79 is provided on the discharge side of the pump 70, but an outflow control valve 82 is provided in the outflow passage 80 that connects the downstream side of the check valve 79 (the side opposite to the pump 70) and the reservoir 76. It is done. The outflow control valve 82 is a mechanical on-off valve that uses the discharge pressure of the pump 70 as a pilot pressure. Although the pump 70 is open when the pump 70 is in an inoperative state, the pump 70 is operated and switched to the closed state when hydraulic fluid is discharged. Since the pump 70 is a gear pump, the pressure on the discharge side is lowered by being inactivated. In the open state of the outflow control valve 82, the hydraulic fluid is caused to flow out from the liquid chamber 36 of the suspension cylinder 24, and the vehicle height is lowered. Reference numeral 84 denotes an accumulator for silencing.

  Individual control valves 90 to 96 are provided in each of the individual passages 50 to 56, and a connection passage 98 for connecting the individual passages 50 and 52 corresponding to the left and right front wheels 10 and 12, and an individual passage corresponding to the left and right rear wheels 14 and 16. Communication control valves 102 and 104 are provided in each of the connecting passages 100 connecting the 54 and 56. These individual control valves 90 to 96, the communication control valves 102 and 104, and the like constitute a vehicle height adjusting valve device 106. The individual control valves 90 to 96 and the communication control valves 102 and 104 are all normally closed electromagnetic on-off valves. The vehicle heights of the left and right wheels are commonly controlled when the communication control valves 102 and 104 are open, and are separately controlled when the communication control valves 102 and 104 are closed. Moreover, the vehicle height for each wheel can be adjusted independently by opening / closing control of the individual control valves 90 to 96.

Each of the individual passages 50 to 56 is connected to two accumulators 110 and 112 corresponding to the suspension cylinder 24, and a spring constant switching valve 114 is provided corresponding to the accumulator 112. Each of the two accumulators 110 and 112 is connected to each of the individual passages 50 to 56 via the branch passages 116 and 118, and the spring constant switching valve 114 is provided in the branch passage 118. In the present embodiment, the accumulator 112 has a smaller spring constant than the accumulator 110.
The hydraulic fluid is exchanged between one suspension cylinder 24 and the two accumulators 110 and 112. When the same amount of hydraulic fluid flows into the accumulators 110 and 112 between the accumulator 110 having a larger spring constant and the accumulator 112 having a smaller spring constant, the increase in elastic force generated in the accumulator 110 is larger. Further, when the amount of change in the fluid pressure in the fluid chamber 36 of the suspension cylinder 24 is the same, the hydraulic fluid is less likely to flow in the accumulator 110.
From the above, when the amount of change in the relative height of the vehicle body 22 with respect to the wheel holding device 20 is the same, the increase in the generated elastic force is greater in the accumulator 110. Further, when the amount of change in load applied between the wheel holding device 20 and the vehicle body 22 is the same, the hydraulic fluid in the accumulator 110 is less likely to be supplied. From these, it can be considered that the elastic body of the accumulator communicated with the suspension cylinder 24 corresponds to a suspension spring provided between the wheel holding device 20 and the vehicle body 22. In this sense, the accumulators 110 and 112 can be referred to as elastic force generating accumulators.
Therefore, if the accumulator communicated with the suspension cylinder 24 is changed or the number of accumulators communicated is changed, the ease of exchanging hydraulic fluid between them changes, and the spring constant of the suspension spring changes. It will be the same as
The spring constant switching valve 114 is a normally open electromagnetic on-off valve, and the spring constant is reduced in the open state and is increased in the closed state.

  The vehicle height adjustment ECU 160 mainly includes a computer, and includes an execution unit 162, a storage unit 164, an input / output unit 166, and the like. The input / output unit 166 is provided for each wheel, detects a vehicle height at a position corresponding to each wheel, a fluid pressure sensor 170 provided in the control pressure passage 60, and a vehicle height adjustment mode selection switch 172. , A vehicle height adjustment instruction switch 174, a transceiver 176, an ignition switch 177 a, a shift position sensor 177 b, a parking brake switch 177 c, a travel speed sensor 178 for detecting the travel speed of the vehicle, etc. The solenoids 78, 82, 90 to 96, 102, 104, 114, the pump motor 72, and the like are connected via a drive circuit (not shown).

The transceiver 176 includes an antenna and the like, and wireless communication of information is performed with the portable device 180.
The portable device 180 is often carried by a passenger such as a driver, and is usually outside the vehicle body before the driver gets on the vehicle. The portable device 180 includes a transceiver 182 provided with an antenna and the like, a control unit 184 mainly composed of a computer, and the storage unit 185 of the control unit 184 stores an identification number ID and the like. From portable device 180, a series of information (referred to as portable device information) including identification information, vehicle height adjustment instruction information, and the like is transmitted.
When the portable device information is received by the vehicle height adjustment ECU 160, the identification number is collated. When it is detected that these correspond to each other, and when a predetermined condition such as that the portable device 180 has entered a predetermined setting area with respect to the vehicle is satisfied, Vehicle height adjustment is started.
In addition, it is not essential that the vehicle height adjustment instruction information is included in the mobile device information transmitted from the mobile device 180. Even if the vehicle height adjustment instruction information is not included, if the portable device 180 approaches the vehicle and enters the setting area, the vehicle height adjustment is started assuming that the vehicle height adjustment is requested. Because it can. From now on, it is highly possible to get into the vehicle, and it is desirable to keep the vehicle height low beforehand. In addition, if the vehicle height adjustment is started from the point of entry into this area, the setting area is set when the portable device 180 approaches the vehicle (when the person holding the portable device 180 gets on the vehicle). This is an area where the high adjustment is considered to be completed. For example, it can be assumed that the set area is entered when the elapsed time since the first reception of portable device information exceeds the set time. Further, depending on the reception capability of the portable device information on the vehicle body side, the vehicle height adjustment may be started on the assumption that the portable device enters the setting region when it enters the receivable region.

The fluid pressure sensor 170 detects the discharge pressure of the pump 70 and the fluid pressure of the accumulator 74. When the accumulator pressure is detected, the pressure accumulation control valve 78 is opened.
The vehicle height adjustment mode selection switch 172 and the vehicle height adjustment instruction switch 174 are operated by the driver. The vehicle height adjustment mode selection switch 172 is operated when switching between the manual mode and the automatic mode, and the vehicle height adjustment instruction switch 174 is operated when increasing or decreasing the vehicle height. In response to the operation of the vehicle height adjustment instruction switch 174, the vehicle height is increased or decreased by a predetermined set amount (a predetermined step).
It can be considered that the get-off intention detection device is configured by the ignition switch 177a, the shift position sensor 177b, the parking brake switch 177c, and the like. When the ignition switch 177a is switched from the ON state to the OFF state, when the parking brake switch 177c is switched from the OFF state to the ON state, when the shift position is switched from the drive position and the reverse position to the parking position, etc. The driver is not willing to start the vehicle and is willing to get off the vehicle.
The storage unit 164 stores a vehicle height adjustment program, an identification number ID, and the like represented by the flowchart of FIG.

The vehicle height adjustment is performed when a predetermined vehicle height adjustment request condition is satisfied.
In this embodiment, (a) when information from the portable device 180 is received, (b) when an instruction to reduce the vehicle height is detected by the vehicle height adjustment instruction switch 172 in the manual mode, (c) automatic mode In the control, the vehicle height is reduced when a predetermined condition is satisfied. In the vehicle height adjustment, when the vehicle height is lowered, the individual control valves 90 to 96 are opened and the outflow control valve 82 is opened.

In the OFF state of the ignition switch 177a, the vehicle height is normally set to the standard vehicle height in order to improve the appearance. On the other hand, since it is difficult for a person to ride at the standard vehicle height, the vehicle height is automatically lowered when “information indicating an instruction to lower the vehicle height” transmitted from the portable device 180 is received.
Further, when an instruction to lower the vehicle height is issued by operating the vehicle height adjustment instruction switch 172 in the manual mode, the vehicle height is lowered.
Further, in the automatic mode, the vehicle height is lowered when the intention to get off is detected after the traveling vehicle stops.
In addition, when the vehicle speed exceeds the set speed during traveling, the vehicle height may be adjusted from “standard” to “low”.

  In this embodiment, the spring constant switching valve 114 is controlled to open and close when the vehicle height is reduced. When the vehicle height is to be reduced, the hydraulic fluid is discharged from the liquid chamber 36 of the shock absorber 24 to the reservoir 76 through the individual passages 50 to 56 and the control pressure passage 60. In this case, when the spring constant switching valve 114 is in the open state and the hydraulic fluid is allowed to flow out from the accumulator 112, the flow passage areas of the individual passages 50 to 56 and the control pressure passage 60 are determined. The flow rate of the hydraulic fluid flowing out from the shock absorber 24 is reduced. On the other hand, if the spring constant switching valve 114 is closed and the outflow of hydraulic fluid from the accumulator 112 is prevented, the vehicle height reduction speed is increased accordingly. However, when there is a request to reduce the vehicle height, if the spring constant switching valve 114 is closed and the vehicle height is reduced, the vehicle height is rapidly reduced. The same applies to the case where the decrease in the vehicle height is terminated. The vehicle height is decreased from a state where the decrease rate of the vehicle height is large, and the change in the decrease rate becomes abrupt.

Therefore, in this embodiment, the spring constant is set to a small state after the first set time elapses after the vehicle height starts to decrease and after the second set time elapses, and the first set time elapses. Then, the spring constant is made large until the second set time elapses.
The first set time and the second set time are shorter than the time when the vehicle height is reduced with the spring constant being small, and the time required for the vehicle height to be reduced to the target vehicle height is reduced. It is set to a size that can suppress a change in the decrease rate.
Furthermore, the first set time and the second set time can be determined each time based on the current vehicle height and the target vehicle height, but the vehicle height and target vehicle height at the start of the reduction control are determined in advance. If it is decided, it can be decided in advance.
Further, it is possible to switch based on the amount of decrease in the vehicle height, not based on the time from the start of the decrease control.

The vehicle height adjustment program represented by the flowchart of FIG. 2 is executed at predetermined time intervals. In step 1 (hereinafter abbreviated as S1. The same applies to other steps), it is determined whether or not there is a request to reduce the vehicle height. If there is a request, in S2, the spring constant switching valve is determined. 114 is opened. In many cases, the spring constant switching valve 114 is already in the open state when S2 is executed, but may be in the closed state, and in that case, the spring constant switching valve 114 is switched to the open state.
In S3, the vehicle height adjustment is started. The individual control valves 90 to 96 are opened so that the vehicle height decreases. When the vehicle height is decreased, that is, when the pump 70 is not operated, the outflow control valve 82 is in an open state. In S4, it is determined whether or not a predetermined first set time has elapsed since the vehicle height reduction control was started. Until the first set time elapses, the two accumulators 110 and 112 are communicated with the suspension cylinder 24 so that the spring constant is small. The vehicle height reduction speed during this period is small.
When the first set time has elapsed, the spring constant switching valve 114 is switched from the open state to the closed state in S5. In S6, it is determined whether the second set time has elapsed. Until the second set time elapses, the accumulator 112 is disconnected from the suspension cylinder 24, the spring constant is increased, and the vehicle height reduction speed increases.
On the other hand, when the second set time has elapsed, in S7, the spring constant switching valve 114 is changed from the closed state to the open state. In S8, it is determined whether or not the actual vehicle height has reached the target vehicle height. The spring constant is made small until the target vehicle height is reached after the second set time has elapsed, and the vehicle height reduction speed is reduced.
And if it falls to target vehicle height, an end process will be performed in S9. The individual control valves 90 to 96 are closed. In addition, the spring constant switching valve 114 may be switched to a closed state.

As shown in FIG. 3, in the vehicle height reduction control, the spring constant switching valve 114 is controlled to open and close, and the number of accumulators communicated with the suspension cylinder 24 (corresponding to the spring constant) is increased or decreased.
In vehicle height adjustment, the reduction speed is reduced at the beginning and end of reduction of the vehicle height, and is increased in the middle to suppress a sudden change in the reduction speed of the vehicle height during the vehicle height reduction control. it can.
As a result, when there are passengers in the vehicle, the deterioration of the feeling at the start of vehicle height reduction and at the end of reduction is suppressed, and when there are no passengers, a sudden movement of the vehicle body is avoided. Even if the vehicle height decreases until it comes into contact with the vehicle, it is possible to reduce the contact sound, and to avoid surprised people in the vicinity.
In addition, since the spring constant switching valve 114 is a normally open valve, power consumption can be reduced as compared with the case where the reduction control is performed with the spring constant switching valve 114 closed.
Further, when the spring constant is set to a small state after the reduction control is finished before the vehicle height reduction control is started, the vehicle height reduction control is executed during the execution of S2 in the vehicle height adjustment in the above embodiment. At the end, there is no need to switch the spring constant switching valve 114, and in particular, the occupant's uncomfortable feeling can be reduced.
In FIG. 3, for the sake of simplicity, the change in the vehicle height is linear and while the spring constant is small (from the start of vehicle height reduction until the first set time has elapsed and the second set time. In the period from when the vehicle height adjustment is completed to when the vehicle height adjustment is completed, the same slope is written. However, in reality, the first set time elapses after the vehicle height reduction starts. (2) The vehicle height reduction speed becomes greater than after the set time has elapsed until the vehicle height adjustment is completed. This is because the difference between the hydraulic pressure of the suspension cylinders 10 to 16 and the hydraulic pressure of the reservoir 78 is large. Further, while the spring constant is large (from the first set time to the second set time elapses), the change gradient of the vehicle height is not constant, and the gradient is gentle as the vehicle height decreases. become. This is because the hydraulic pressure difference between the suspension cylinders 10 to 16 and the reservoir 78 becomes small.

  In the present embodiment, the accumulator distribution control device is configured by a portion that stores S2-8 of the vehicle height adjustment program represented by the flowchart of FIG. Of the accumulator flow control device, a part that controls the spring constant switching valve 114 that is an electromagnetic control valve (a part that stores S2, 5, and 7, a part that executes it, etc.) constitutes a solenoid valve control unit. Further, the shut-off state switching unit is configured by the part storing S4, 5 and the part for executing the communication, and the communication state switching unit is configured by the part storing S6, 7 and the part for executing.

  In the above embodiment, the spring constant is small at both the vehicle height reduction start time and the reduction end time. However, at either the reduction start time or the reduction end time, the spring constant is It may be in a large state. Even in such a case, it is possible to suppress a rapid change in the decrease rate as compared with the case where the decrease control is performed with the spring constant switching valve 114 closed. In this case, reducing the spring constant at the start of vehicle height reduction is more effective in suppressing sudden changes in vehicle height reduction speed.

Further, in the above embodiment, the opening / closing control of the spring constant switching valve 114 is performed based on the elapsed time from the start of the vehicle height adjustment, but may be performed based on the vehicle height reduction amount. it can. In the flowchart of FIG. 4, the actual vehicle height reduction amount is obtained by subtracting the current vehicle height from the vehicle height at the time when vehicle height adjustment is started. In S4 ′, the actual vehicle height reduction amount is It is determined whether or not the first set decrease amount has been reached. When the first set decrease amount has been reached, the spring constant switching valve 114 is switched from the open state to the closed state in S5. Then, in S6 ′, it is determined whether or not the actual vehicle height reduction amount has reached the second set reduction amount. When the actual vehicle height reduction amount has reached the second set reduction amount, the spring constant switching valve 114 is closed in S7. To the open state.
The first set decrease amount and the second set decrease amount can be vehicle height decrease amounts corresponding to the first set time and the second set time, respectively, in the above embodiment.

Further, in the above embodiment, the spring constant switching valve 114 is controlled to open and close when there is a request to reduce the vehicle height both when the vehicle is running and when it is stopped. This is executed when there is a request to reduce the vehicle height, and may not be executed during traveling.
Further, in the vehicle height adjustment device, when the high speed vehicle height adjustment and the low speed vehicle height adjustment are performed, the above-described embodiment may be applied to the high speed vehicle height adjustment, and may not be applied to the low speed vehicle height adjustment. it can. For example, when an instruction to reduce the vehicle height is transmitted from the portable device 180, the high-speed vehicle height adjustment is executed when the vehicle height adjustment instruction switch 174 is operated, and the low-speed vehicle height adjustment is executed in the running state. Can be.

Further, the above embodiment is applied when the vehicle height is reduced on either the front wheel side or the rear wheel side, and is not applied when the vehicle height is reduced on the other side. It may be applied sometimes. For example, it can be applied when the vehicle height is adjusted on the front wheel side and not applied on the rear wheel side.
In addition, when the spring constant switching valve 114 is switched between open and closed, so-called duty control can be performed in which the spring constant switching valve 114 is switched between an open state and a closed state at short time intervals.
Further, the spring constant switching valve 114 can be a linear control valve or a variable throttle whose flow path area can be changed in the open state, and when the linear control valve or the variable throttle is used, during the vehicle height reduction control, By changing the flow path area continuously, the change in the vehicle height reduction speed can be smoothed. However, as in the above embodiment, if the opening / closing control is performed using the electromagnetic opening / closing valve, the same effect can be obtained, and the spring constant switching valve 114 can be a linear control valve or a variable throttle. The spring constant switching valve can be made inexpensive.
Furthermore, the outflow control valve 82 can be an electromagnetic on-off valve that is opened and closed by turning on and off the supply current to the solenoid. The outflow control valve may be a normally open valve or a normally closed valve, and is at least opened when the vehicle height is decreased and closed when the vehicle height is increased.

The control for closing the spring constant switching valve 114 during vehicle height adjustment can also be applied to control for increasing the vehicle height.
Further, in the above embodiment, the vehicle height adjusting device uses the hydraulic fluid as the fluid. However, the present invention can use air as well as the above-described embodiments. The present invention can be implemented in various modifications and improvements based on the knowledge of the trader.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram conceptually showing an entire vehicle height adjusting device as one embodiment of the present invention. It is a flowchart showing the vehicle height adjustment program memorize | stored in the memory | storage part of the vehicle height adjustment ECU of the said vehicle height adjustment system. It is a figure which shows the example of control by the said vehicle height adjustment apparatus. It is a flowchart showing another vehicle height adjustment program memorize | stored in the memory | storage part of the said vehicle height adjustment ECU.

Explanation of symbols

24: Suspension cylinder 58: Fluid control device 82: Outflow control valve 90-96: Individual control valve 106: Vehicle height adjustment valve device 160: Vehicle height adjustment ECU 168: Vehicle height sensor

Claims (4)

Corresponding to the wheel of the vehicle, a fluid cylinder provided between the wheel holding device and the vehicle body,
A fluid control device capable of adjusting a vehicle height between a wheel holding device for the wheel and a portion of the vehicle body where the fluid cylinder is provided by allowing fluid to flow into or out of the fluid cylinder;
One or more accumulators connected to the fluid cylinder;
Fluid from at least one of the one or more accumulators at a time when the fluid control device causes the fluid to flow out of the fluid cylinder to reduce the vehicle height corresponding to the fluid cylinder. a vehicle height adjusting device comprising an accumulator flow control device which prevents the outflow,
The at least one accumulator is connected to a fluid passage connecting the fluid cylinder and the fluid control device;
The accumulator flow control device is provided with (i) at least one electromagnetic control provided between the at least one accumulator and the fluid passage and capable of switching between at least a communication state for communicating them and a blocking state for blocking them. A valve, and (ii) when the first set time has elapsed from the start of the vehicle height reduction by the fluid control device, and the vehicle height reduction amount from the vehicle height reduction start time is greater than or equal to the first set reduction amount And a solenoid valve control unit having a shut-off state switching unit that switches the at least one electromagnetic control valve from an open state to a closed state . When the solenoid valve control unit has passed a second set time longer than the first set time from the start of the vehicle height decrease by the fluid control device, and the vehicle height decrease from the vehicle height decrease start time. in either the case where the amount is equal to or greater than the amount of decrease of the first set decrease amount is greater than the second set, claims, including communicating state converter for switching the at least one electromagnetic control valve to the open state from the closed state 1. The vehicle height adjusting device according to 1. Two accumulators are connected to the fluid cylinder, one of which has a smaller spring constant than the other, one of the accumulators is connected to the fluid passage through the electromagnetic control valve, and the electromagnetic valve control unit The vehicle height adjusting device according to claim 1, further comprising a spring constant switching control unit configured to switch the electromagnetic control valve from an open state to a closed state so that a spring constant is large. Corresponding to the wheel of the vehicle, a fluid cylinder provided between the wheel holding device and the vehicle body,
A fluid control device capable of adjusting a vehicle height between a wheel holding device for the wheel and a portion of the vehicle body where the fluid cylinder is provided by allowing fluid to flow into or out of the fluid cylinder;
One or more accumulators connected to the fluid cylinder;
When a fluid is caused to flow out to the fluid cylinder by the fluid control device to reduce the vehicle height corresponding to the fluid cylinder, after a first set time has elapsed from the start of the vehicle height reduction. , The flow of fluid from the one or more accumulators is reduced more than when the vehicle height decrease amount from the start of vehicle height decrease is greater than or equal to the first set decrease amount. A vehicle height adjusting device comprising: an accumulator distribution control device for suppressing the vehicle.

Images