JPS6342647Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a vehicle height adjustment device.

Various types of automobiles have been developed in which the vehicle height can be adjusted from the viewpoint of ride comfort and handling stability.

By the way, when driving at high speed, it is desirable to move from a standard vehicle height state to a low vehicle height state from the viewpoint of air resistance and steering stability.

However, with conventional means, if the vehicle speed is e.g.
The vehicle height is changed from normal to low at speeds of 75 km/h or higher, and returns to normal vehicle height at speeds of 75 km/h or lower.
When driving at around Km/h, there is a problem in that the vehicle height changes frequently, a so-called chattering phenomenon, which makes the ride very uncomfortable.

The present invention aims to solve these problems, and aims to provide a vehicle height adjustment device that can reliably prevent the above-mentioned chattering phenomenon and improve ride comfort. do.

Therefore, the vehicle height adjustment device of the present invention includes a hydraulic suspension unit that is interposed between the wheel side member and the vehicle body side member and has a fluid chamber for adjusting the vehicle height, and adjusts the vehicle height according to the vehicle speed. In order to adjust the vehicle speed, a vehicle speed sensor that detects the vehicle speed and a vehicle height sensor that detects the vehicle height are provided. If the vehicle height is not in the low vehicle height state when the condition continues for more than the first set time, fluid is discharged from the fluid chamber in the suspension unit to bring the vehicle height to the low vehicle height state, and the vehicle speed is reduced. When the vehicle height is in the low vehicle height state when the condition where the vehicle height is equal to or less than the second set value which is smaller than the first set value continues for a second set time shorter than the first set time, The vehicle is characterized by being provided with a vehicle height adjustment control section that adjusts the vehicle height to raise the vehicle height by supplying fluid to the fluid chamber.

The vehicle height adjustment device as an embodiment of the present invention will be explained below with reference to the drawings. Fig. 1 is a schematic diagram showing a car equipped with this device, Fig. 2 is a sectional view of the main part of the suspension unit, and Fig. 2 is a schematic diagram showing a car equipped with this device. 3 is a block diagram of its main parts, FIG. 4 is a diagram of its overall configuration, and FIG. 5 is a flowchart for explaining its operation.

As shown in Figures 1 and 4, front air suspension units FS1 and FS2 are interposed between the left and right ends of the front wheel axle and the vehicle body B side member, respectively, and the left and right ends of the rear wheel axle are Rear air suspension units RS1 and RS2 are interposed between both ends and the vehicle body B side member, respectively.

These air suspension units FS1,
FS2, RS1, and RS2 have almost the same structure, and the details are as follows.
It will look like the figure. Hereinafter, the reference numeral S will be used for the air suspension unit unless the front and rear air suspension units are specifically explained.

That is, these air suspension units S incorporate a strut type damping force switching type shock absorber 4, and this shock absorber 4 includes a cylinder 1a attached to the front wheel or rear wheel side, The piston 19 is slidably inserted into the piston 1a.

The piston 19 also includes orifice passage portions 19a, 19b, 19 that are communicatively connected to each other.
A first chamber 1b and a second chamber 1c partitioned by a piston 19 are formed by the orifice passage.
It is now possible to cut off communication.

Note that each chamber 1b, 1c is filled with hydraulic oil.

Furthermore, the piston 19 includes a piston rod 5.
The piston rod 5 extends upward, passes through the first chamber 1b in a fluid-tight manner, and the upper end of the piston rod is supported by a frame 9 on the vehicle body B side via a bearing 6 and a mount rubber 7. has been done. This support is performed using bolts or the like, and is fixed at several locations.

Incidentally, the vertical movement of the piston rod 5 is restricted by a nut or the like, but rotation is allowed by a bearing 6.

By the way, a drive pin 15 is provided inside the piston rod 5, and this drive pin 15 extends in the longitudinal direction of the piston rod 5 and is provided so as to be able to slide relative to the piston rod 5. There is.

Further, the lower end of the drive pin 15 extends into a space forming a part of the orifice passage in the piston 19, and a shutter 15a as a control valve body is attached to the lower end of the drive pin.
9a and 19a are installed so that they can be opened and closed.

Further, the upper end of the drive pin 15 extends further upward than the upper end of the piston rod 5, and a solenoid mechanism 13 for driving the shutter 15a via the drive pin 15 is connected to the upper end of the drive pin 15. ing.

This solenoid mechanism 13 engages the upper end protrusion of the drive pin 15 with the notch of the arm, and rotates the drive pin 15 by the tensile force of the soft solenoid and the hard solenoid. There is.

In order to shift from the hard state to the soft state using this solenoid mechanism 13, the soft solenoid is driven, the drive pin 15 is rotated to a predetermined position, and the orifice passage portion 19a is placed in a communicating (open) state. What is necessary is to increase the effective circulation area through which the hydraulic oil flows.

Further, in order to shift from the soft state to the hard state by the solenoid mechanism 13, the hard solenoid is driven, the drive pin 15 is rotated to a predetermined position in the opposite direction to the above, and the orifice passage portion 19a is moved. The shutoff (closed) state may be achieved by reducing the effective circulation area through which the hydraulic fluid flows.

By driving the solenoid mechanism 13 in this way, it becomes possible to switch the damping force, and the solenoid mechanism 13, drive pin 15 or shutter 15
A damping force switching mechanism D is configured by a and the like.

Therefore, in this damping force switching type shock absorber 4, the cylinder 1a on the outside of the body moves up and down with respect to the piston rod 5 in accordance with the up and down movement of the wheel, thereby exerting a damping function according to the position of the shutter 15a. It is now able to absorb shots effectively.

By the way, a main air spring chamber 2 which also serves as a vehicle height adjustment fluid chamber is disposed above the shock absorber 4 coaxially with the piston rod 5.
Since a part of the main air spring chamber 2 is formed by a bellows 20, the piston rod 5 can be moved up and down by supplying and discharging air to the main air spring chamber 2.

Further, a sub air spring chamber 10 is disposed coaxially with the piston rod 5 directly above the main air spring chamber 2 .

Further, the outer wall of the shock absorber 4 is provided with a spring receiver 16a facing upward, and the outer wall of the auxiliary air spring chamber 10 is provided with a spring receiver 16a facing downward.
6b are formed, and these spring receivers 16a,
A coil spring 3 is loaded between 16b.

Further, these air spring chambers 2 and 10 are connected to each other via a communication passage 11 bored across the drive pin 15 and the piston rod 5, and a spring constant switching mechanism E is connected to the communication passage 11. An on-off valve 12 is interposed.

This on-off valve 12 has a first valve part 12a that cuts off communication between the auxiliary air spring chamber 10 and the communication passage 11, and a second valve part 12b that cuts off communication between the main air spring chamber 2 and the communication passage 11. It is constructed in advance.

Therefore, when the valve portion 12a is in the open mode, the main air spring chamber 2 and the auxiliary air spring chamber 10 are brought into communication, the spring constant can be made small (soft), and the valve portion 12a is in the closed mode. When in mode,
By putting the main air spring chamber 2 and the sub air spring chamber 10 in a disconnected state, the spring constant can be increased (hardened).

That is, by rotating the drive pin 15, the on-off valve 12 can be opened and closed, and by this opening and closing, the spring chamber capacity can be changed.

By changing this spring chamber capacity, the spring constant of the suspension can be changed.

By the way, the compressed air for adjusting the vehicle height is
As shown in the figure, a compressor 21 as a compressed air generator, a dryer 22, a joint 2
3. It is supplied to each suspension unit S via the rear solenoid valve 24, the front solenoid valve 25, the piping 1 that connects these, and the communication passage 11 inside the partially pipe-shaped drive pin. There is.

The compressor 21 compresses the air sent from the air cleaner 37 and supplies it to the dryer 22. The compressed air dried by silica gel or the like in the dryer 22 is shown by the solid line arrows in FIG. Like, suspension unit S
supplied to

Furthermore, when the compressed air is exhausted from the suspension unit S, as shown by each broken line arrow in FIG.
The compressed air is released to the atmosphere.

Note that the dryer 22 includes a reserve tank 39.
A portion of the compressed air is supplied from this reserve tank 39 to each suspension unit S via an air supply solenoid valve 40.

In addition, as shown in Figs. 3 and 4, the vehicle height sensor 1
7 is provided, and this vehicle height sensor 17 is a front vehicle height sensor 1 that is attached to the lower arm 26 on the front right side of the vehicle and detects the front vehicle height of the vehicle.
7F and lateral rod 29 on the left side of the rear of the car.
and a rear vehicle height sensor 17R that is attached to the rear vehicle height sensor 17R to detect the rear vehicle height of the vehicle.
A front vehicle height detection signal and a rear vehicle height detection signal are supplied from these vehicle height sensors 17F and 17R to a control unit 14 serving as a vehicle height adjustment control section.

In addition, each sensor 17 in the vehicle height sensor 17
F, 17R has a Hall IC element and a magnet, one of which is attached to the wheel side and the other to the vehicle body B side, to detect the distance from the normal vehicle height level and the low or high vehicle height level, respectively. There is.

Furthermore, the speedometer 33 has a built-in vehicle speed sensor 18, which detects the vehicle speed and supplies a detection signal to the control unit 14, as shown in FIGS. Mechanical speedometers use a reed switch type vehicle speed sensor.
An electronic speedometer uses an open collector output type sensor using a transistor.

Further, an acceleration sensor 35 is provided as a vehicle body posture sensor that detects changes in the posture of the vehicle body.
This acceleration sensor 35 is designed to detect changes in the pitch, roll, and yaw of the car body on the car's springs. For example, when there is no acceleration, the weight is in a hanging state, and the light from the light emitting diode is directed toward the shielding plate. The structure is such that the absence of acceleration can be detected by blocking the light from reaching the photodiode.

When acceleration acts in the front and back, left and right, or up and down directions, the weight tilts or moves, and the acceleration state of the vehicle body is detected.

The symbol LF in Fig. 4 indicates the boundary between the engine room (left of the broken line LF) and the passenger compartment (between the broken lines LF and LR), and LR indicates the border between the passenger compartment and the trunk room (between the broken lines LF and LR).
(to the right of LR).

Reference numeral 8 in FIG. 2 indicates a bump stopper for preventing damage to the wall surface of the main air spring chamber 2 due to the relative rise of the cylinder 1a of the shock absorber 4 on rough roads. There is.

By the way, the control unit 14 receives signals from the vehicle height sensor 17 and the vehicle speed sensor 18 and a signal from a timer built into the control unit, and sends control signals to the solenoid valves 24, 25, and 25 to adjust the vehicle height according to the vehicle speed. 38 and 40.

That is, this control unit 14 is
When the vehicle speed continues to be higher than the first set value (for example, 100 km/h) for more than the required time (for example, 10 seconds), each solenoid valve 24, 25, By outputting an open signal to 38 and discharging compressed air from the main air spring chamber 2 of the suspension unit S, the vehicle height is brought to a low vehicle height state, and a second set value smaller than the first set value is set. (for example, 90 km/h) or lower for a short period of time (for example, 0 to 3 seconds), check that the vehicle height is not at normal vehicle height or high vehicle height, and then ,25,4
By outputting an open signal to the main air spring chamber 2 and supplying compressed air to the main air spring chamber 2, the vehicle height is raised to the normal vehicle height.

In addition, in the soft state, air is simultaneously supplied and discharged to the auxiliary air spring chamber 10.

Here, a series of processing flows carried out within this control unit 14 are shown in Fig. 5, but in order to realize this flow, it is possible to use software or hardware. .

With the above-described configuration, the compressed air supplied from the compressor 21 is received in the main air spring chamber 2, and the vehicle height can be adjusted depending on the pressure level.The height of the vehicle is determined by the front vehicle height sensor. Detected by 17F and rear vehicle height sensor 17R,
These detection signals are supplied to the control unit 14, and a control signal based on the detection signals is sent from the control unit 14 to the compressor 21.
The vehicle height is adjusted by being supplied to the vehicle.

By the way, the high speed driving state of 100km/h or more is 10
If this continues for more than a second, the control unit 14 confirms that the vehicle height is not in the low vehicle height state and sends an opening signal to the solenoid valves 24, 25, and 38.
The vehicle height shifts to a low vehicle height state. This reduces air resistance while driving and improves steering stability.

Then, when the vehicle speed decreases from 100km/h or more to 90km/h or less, and this state continues for about 0 to 3 seconds, the control unit 14 changes the vehicle height to the normal vehicle height state. Check that there are no solenoid valves 24, 25, 40.
Since the vehicle open signal is output, the vehicle height returns to the normal vehicle height state.

In this way, the vehicle height is adjusted appropriately according to the vehicle speed, which improves handling stability.In addition, hysteresis is provided when returning from a low vehicle height state to a normal vehicle height state, making it possible to adjust the height of the vehicle appropriately depending on the vehicle speed. There is no chattering phenomenon, which greatly improves riding comfort.

Note that the vehicle does not shift to the low vehicle height state unless the vehicle is traveling at a speed higher than the first set value for the required time, so the chattering phenomenon occurs when transitioning from the normal vehicle height state to the low vehicle height state. is also prevented.

In addition, even if the vehicle is traveling at a speed below the second set value for a short time, it will return to the normal vehicle height state, but even if the vehicle height is restored in this way, there will be a difference in the reaction speed. Therefore, the chattering phenomenon is sufficiently prevented.

In addition, in this device, when the vehicle speed continues to be higher than the first set value for a first set time or longer and the vehicle height is not in the low vehicle height state, the vehicle height is switched to the low vehicle height state,
When the vehicle height is in the low vehicle height state when the vehicle speed remains below the second set value, which is smaller than the first set value, for a second set time shorter than the first set time. Since the vehicle is configured to raise the vehicle height, most of the so-called delay time to prevent excessive vehicle height switching is set in the first set time, and the second set time is kept as short as possible. As a result, even when you suddenly decelerate from high speed driving to driving on rough roads, there is no significant delay in switching the vehicle height from ``low'' to ``high''. This also has the advantage of preventing interference between road surface protrusions and the vehicle body due to this delay.

By using the suspension unit S used in this device, the spring constant and damping force switching can also be controlled appropriately according to the driving conditions of the vehicle.

As described in detail above, the vehicle height adjustment device of the present invention includes a fluid pressure suspension unit interposed between the wheel side member and the vehicle body side member and having a fluid chamber for adjusting the vehicle height. In order to adjust the vehicle height according to the vehicle height, a vehicle speed sensor that detects the vehicle speed and a vehicle height sensor that detects the vehicle height are provided, and
In response to signals from the vehicle speed sensor and vehicle height sensor, if the vehicle speed is not in the low vehicle height state when the vehicle speed remains at or above the first set value for the first set time or longer, Fluid is discharged from the fluid chamber in the suspension unit to bring the vehicle height to the low vehicle height state, and the vehicle speed is lower than the second set value, which is smaller than the first set value, than the first set time. vehicle height adjustment that adjusts the vehicle height to raise the vehicle height by supplying fluid to the fluid chamber if the vehicle height is in the low vehicle height state when the vehicle height continues for a short second set time or longer; With a simple configuration that includes a control unit, it is possible to adjust the vehicle height according to vehicle speed while reliably preventing the chattering phenomenon, which not only improves handling stability but also significantly improves ride comfort. There are advantages.

The vehicle height adjustment device of the present invention also has the advantage of minimizing the delay in switching the vehicle height from "low" to "high" to prevent interference between road surface protrusions and the vehicle body.

[Brief explanation of drawings]

The figures show a vehicle height adjustment device as an embodiment of the present invention. Fig. 1 is a schematic diagram showing a car equipped with this device, Fig. 2 is a sectional view of the main part of the suspension unit, and Fig. 3 is a schematic diagram showing a car equipped with this device. The figure is a block diagram of the main parts,
FIG. 4 is a diagram of its overall configuration, and FIG. 5 is a flowchart for explaining its operation. 1... Piping, 1a... Cylinder, 1b... First
Chamber, 1c...Second chamber, 2...Main air spring chamber that also serves as a vehicle height adjustment fluid chamber, 3...Coil spring, 4...Shock absorber, 5...Piston rod, 6...Bearing, 7... Mount rubber, 8... Bump stopper, 9... Frame, 1
0...Sub-air spring chamber, 11...Communication path, 12...
Opening/closing valve, 12a, 12b... Valve portion, 13... Solenoid mechanism, 14... Control unit as a control section, 15... Drive pin, 15a... Shutter, 16a, 16b... Spring receiver, 17, 17
F, 17R...Vehicle height sensor, 18...Vehicle speed sensor, 19...Piston, 19a, 19b, 19c
... Orifice passage part, 20 ... Bellows, 2
1...Compressor as a compressed air generator,
22...Dryer, 23...Joint, 24...
...Rear solenoid valve, 25...Front solenoid valve, 26...Lower arm, 27...Vehicle height determination section, 29...Lateral rod, 33...Speedometer, 35...Acceleration sensor, 37...
Air cleaner, 38...exhaust solenoid valve,
39... Reserve tank, 40... Air supply solenoid valve, D... Damping force switching mechanism, E... Spring constant switching mechanism, S, FS1, FS2, RS1, RS2...
...Suspension unit.

Claims (1)

[Scope of utility model registration request] A vehicle speed sensor that includes a fluid pressure suspension unit that is interposed between the wheel side member and the vehicle body side member and has a fluid chamber for adjusting vehicle height, and detects the vehicle speed in order to adjust the vehicle height according to the vehicle speed; A vehicle height sensor is provided to detect the vehicle height, and when the vehicle speed remains at a first set value or higher for a first set time or more in response to signals from the vehicle speed sensor and vehicle height sensor, the vehicle detects the vehicle height. If the vehicle is not in the low vehicle height state, the fluid is discharged from the fluid chamber in the suspension unit to bring the vehicle height to the low vehicle height state, and the vehicle speed is lower than the first setting value. If the vehicle height is in the low vehicle height state when the condition below the set value continues for a second set time shorter than the first set time, fluid is supplied to the fluid chamber to lower the vehicle height. 1. A vehicle height adjustment device, comprising a vehicle height adjustment control section that adjusts the vehicle height so as to raise the height of the vehicle.