JPH0516631A - Suspnesion device of vehicle - Google Patents

Abstract

PURPOSE:To prevent a variation of the grounding load in a bad road running condition by providing a means to cushion the up and down movement between the left and the right ends of an axle housing, and the left and the right parts of a car body, and a means to generate a reaction force to a deflection of the shaft fulcrum of a lateral link. CONSTITUTION:In a suspension device 10B, a Watts link type lateral link 44 extending along almost in the car width direction, whose center is pivoted rotatable to an axle housing 34, and whose both ends are connected to a car body 12, is provided. And an air spring type damper 62 to generate a reaction force to a deflection of the shaft fulcrum of the Watts link type lateral link 44 to the axle housing 34 is provided. As a result, the air spring type damper 62 is operated in a bad road running condition, and the car body 12 is supported mainly by the damper 62, and by reducing the cushioning function of air spring type dampers 58 and 60 positioned at both ends, the variation of the grounding load is prevented, and the running capacity on a bad road can be secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device for a vehicle in which a vehicle body is elastically supported via a shock absorber, and more particularly, an axle type vehicle suspension provided with a Wattlink type lateral link. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, when traveling normally, for example, when traveling at high speeds on a highway, and when traveling on bad roads, for example, when traveling at low speeds on a road where many rocks are exposed such as riverbeds and mountain roads. It is well known that, in terms of running performance, opposite characteristics are required when focusing on the roll rigidity of suspension. That is, in order to ensure running stability during high-speed running, the roll rigidity is increased to maintain the vehicle body posture strongly, and to maintain a high level against lateral force when receiving a side wind or turning a curve. It is something that must be done. On the other hand, in order to ensure the running performance on rough roads, the roll rigidity can be lowered to prevent the body from wobbling, the suspension stroke can be effectively drawn out, and the ground load on both wheels can be stabilized. It is something that must be done.

[0003]

However, in the conventional suspension device, for example, in Japanese Utility Model Publication No. 63-
As disclosed in Japanese Patent No. 189705, if a rigid type (that is, an axle type) suspension device is adopted to ensure running stability at high speed running, running performance on a bad road becomes worse. On the other hand, if an attempt is made to improve the running performance on a rough road, the running stability at high speed running will be deteriorated.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a suspension device for a vehicle capable of preventing the fluctuation of the ground load when traveling on a rough road. Another object of the present invention is to provide a suspension device for a vehicle that does not require additional parts such as a bracket and can improve the mountability.

[0005]

In order to achieve the above-mentioned object, a vehicle suspension device according to the present invention comprises:
An axle housing having a built-in shaft for connecting the left and right wheels to each other, a cushioning means for cushioning vertical movement between the left and right end portions of the axle housing and the left and right portions of the vehicle body, and extending along substantially the vehicle width direction. The center portion of the axle housing is rotatably supported by the axle housing, and both ends of the Watlink type lateral link are connected to the vehicle body. It is characterized by comprising a reaction force generating means for generating a reaction force.

Further, in the vehicle suspension device according to the present invention, the buffering means is provided on both sides of the axle housing and elastically supports both sides of the vehicle body in the vehicle width direction. The air spring type damper, and the reaction force generating means has a third air spring type damper interposed between the vehicle body and the shaft fulcrum of the water link type lateral link to the axle housing. Is characterized by.

Further, in the vehicle suspension device according to the present invention, the Watt-link type lateral link is pivotally supported at the central portion of the axle housing, and the third air-spring type damper is provided in the vehicle width of the vehicle body. It is characterized by elastically supporting the central part in the direction. Further, in the vehicle suspension device according to the present invention, the first to third cushioning means are respectively set to have variable air pressures, and the respective air pressures of the first to third air spring dampers are controlled. It is characterized by being variably controlled by means.

Further, in the vehicle suspension device according to the present invention, the control means sets the air pressure of the third air spring damper to substantially zero in the normal traveling mode and in the rough road traveling mode. It is characterized by controlling so as to maintain a predetermined value. Further, in the vehicle suspension device according to the present invention, the control means sets the air pressure of the third air spring damper to substantially zero in the normal traveling mode, and the first and second air The air pressure of the formula damper is set to a first predetermined value, and the air pressure of the third air spring damper is maintained at a second predetermined value in a bad road traveling mode, and the first and second air spring types are also set. It is characterized by controlling to reduce the air pressure of the damper.

Further, in the vehicle suspension device according to the present invention, the Watt-link type lateral link has a swing link whose central portion is axially supported by the axle housing, and one end of the swing link. One link that is pivotally supported, extends in one direction along the vehicle width direction, and has the other end pivotally supported by the vehicle body, and one end that pivots to the other end of the swing link. It is characterized in that it is provided with another link that is freely rotatably supported, extends to the other along the vehicle width direction, and has the other end rotatably rotatably supported by the vehicle body.

Further, in the vehicle suspension device according to the present invention, the reaction force generating means is interposed between the other end of the swing link and the one link, and elastically supports both. One of the springs and the other spring interposed between one end of the swing link and the other link and elastically supporting both of them are provided.

Further, in the vehicle suspension device according to the present invention, the swing link includes a shaft portion fixed to the axle housing, and a link body rotatably attached to the shaft portion. The reaction force generating means includes a torsion spring wound around the shaft portion, one end of which is hooked to the axle housing and the other end of which is hooked to the link body.

[0012]

In the vehicle suspension device configured as described above, in normal traveling conditions such as high-speed traveling, only the buffer means provided at both ends is actuated to cancel the reaction force action of the reaction force generation means. By using it like this, high roll rigidity can be obtained and running stability can be secured. On the other hand, when traveling on a rough road, the reaction force generating means is actuated to mainly support the vehicle body and weaken the cushioning function of the cushioning means located at both ends to obtain a low roll rigidity and reduce the ground load. By stabilizing, it will be possible to ensure the running performance on rough roads.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a first embodiment of a vehicle suspension device according to the present invention will be described in detail below with reference to FIGS. 1 to 8 of the accompanying drawings. First, as shown schematically in FIG. 1, the suspension device 10 of the first embodiment is a device for suspending a vehicle body 12 on a total of four wheels on the front, rear, left and right sides. FR to car body 12
The front suspension device 10A suspends the front part of the vehicle body, and the rear suspension device 10B suspends the rear part of the vehicle body 12 on the left and right rear wheels RL, RR.

These suspension devices 10A and 10B
The configuration will be described in detail later, but it is provided with shock absorbers 14A and 14B having a plurality of air spring type dampers, and compressed air is introduced into the air spring type dampers, in other words, air having a predetermined pressure is supplied. For introduction, the suspension device 10 includes an air supply mechanism 16 inside the vehicle body 12. The air supply mechanism 16 appropriately supplies an air pump 18 driven by an engine (not shown), an accumulator 20 for temporarily storing compressed air discharged from the air pump 18, and compressed air accumulated in the accumulator 20. A valve mechanism 22 for supplying the front side and rear side suspension devices 10A and 10B.
It is composed of A and 22B.

The air pump 18 and the valve mechanisms 22A, 2
A control unit 24 is connected to 2B, and under the control of this control unit 24, drive control is performed for each. Here, in the control unit 24,
The vehicle speed sensor 26 that detects the current vehicle speed and the vehicle height sensors 28A and 28B that detect the front and rear vehicle heights, respectively, are connected, and the detected vehicle speed information (V) from the vehicle speed sensor 26 and the vehicle height sensors 28A and 28B are connected. Based on the detected vehicle height information (H) from (1), the valve mechanisms 22A and 22B are drive-controlled to control the suspension state of the suspension device 10.

Here, the suspension devices 10A and 10A are provided within a range that can be reached from a driver seated in a driver's seat (not shown).
A manual switch 30 for manually switching the drive mode B between the bad road traveling mode and the normal traveling mode other than this is provided. This Manual Switch 3
0 is set so that when turned on, the bad road traveling mode is set manually, and when turned off, the normal traveling mode is set manually. This Manual Switch 30
Is connected to the control unit 24, and is configured to output the mode setting information in the manual switch 30 to it. On the other hand, the transmission of the engine (not shown) is provided with an inhibitor switch indicating the currently set shift speed. Further, this vehicle is configured as a four-wheel drive vehicle in the first embodiment, and although not shown, an auxiliary transmission for switching between the rear-wheel drive mode and the four-wheel drive mode is provided. There is. The auxiliary transmission is provided with an auxiliary transmission inhibitor switch 32 that indicates the currently set drive mode, and the auxiliary transmission inhibitor switch 32 is also connected to the control unit 24. It is configured to output drive mode information. From the auxiliary transmission inhibitor switch 32, a 2D signal indicating the setting state of the rear wheel drive mode in the auxiliary transmission, a 4H signal indicating the setting state of the high speed side four-wheel drive mode, and a low speed side four-wheel drive. A 4L signal indicating the mode setting state is selectively output.

The configurations of the front and rear suspension devices 10A and 10B, which characterize the present invention, will be described in detail below with reference to FIGS. Here, as described above, since the vehicle is the four-wheel drive vehicle in the first embodiment, the front and rear suspension devices 10A and 10B are substantially the same in terms of the features of the present invention. It is configured. Therefore, in the following description, the rear suspension device 10B will be described as a representative, and the description of the front suspension device 10A will be omitted and simply referred to as the suspension device 10B.

First, as shown in FIG. 2, the suspension device 10B includes an axle housing 34 extending along the vehicle width direction between the two wheels RL and RR. Although not shown, the final gear, the differential gear, and the axle shaft are built in, and these are integrally assembled to adopt the well-known suspension axle type (that is, fixed axle type) suspension structure. . As is well known, the left and right wheels RL and RR are connected to both ends of the axle shaft via wheel supports (not shown), and are driven according to the rotation of the axle shaft.

Further, the suspension device 10B is
A left upper link 36 that connects the upper part of the left part of the axle housing 34 to the vehicle body, a left lower link 38 that connects the lower part of the axle housing 34 to the vehicle body, and the axle housing 3
4 includes a right upper link 40 that connects the upper part of the right part of 4 with the vehicle body, and a right lower link 42 that connects the lower part of the right upper link with the vehicle body. Here, these links 36,3
All of 8, 40, 42 are designed to extend along the longitudinal direction of the vehicle body. Furthermore, this suspension device 1
The lateral link 44 extends along the vehicle width direction and is rotatably supported by the central portion of the axle housing 34 at the central portion thereof, and the left and right ends thereof are connected to the vehicle body.
Is equipped with.

In the present invention, the lateral link 44 is composed of a water link. That is,
The Watt link 44 is swingably supported around a support shaft 46 extending along the vehicle body front-rear direction at the center of the rear surface of the axle housing 34 (that is, the vehicle width direction center), and is supported by the vehicle body. In the state where no lateral force is applied, the swing link 48 brought to a position extending along the substantially vertical direction, the lower end of the swing link 48 and the vehicle body are connected to each other, and the swing link 48 extends along the vehicle width direction. Left link 5 that extends toward the left
0, and a right link 52 that connects the upper end of the swing link 48 and the vehicle body and extends rightward along the vehicle width direction.

On the other hand, the above-mentioned rear shock absorber 14B is
In the state where it is located at both ends of this axle housing 34,
First and second coil springs 5 for elastically supporting the left and right rear portions of the vehicle body 12 with fixed elastic coefficients.
4, 56 and the first and second coil springs 5
4, 56 are provided in parallel and are provided with first and second shock absorbing mechanisms 58, 60 for elastically supporting with a variable elastic coefficient, and these first and second shock absorbing mechanisms 58, 60 are In the first embodiment, each is composed of an air spring type damper. Also, the rear shock absorber 14B is
In a state of being located in the central portion of the axle housing 34, a third cushioning mechanism 62 is provided for cushioning the vertical movement of the central portion of the rear portion of the vehicle body 12. The third cushioning mechanism 62 is the first embodiment. In the above, the first and second air spring type dampers 58 and 60 are constituted by the same air spring type damper. In detail, as shown in FIG. 3, the third air spring type damper 62 has a lower end pivotally attached to the above-described support shaft 46 and an upper end pivotally attached to the lower surface of the vehicle body. There is. Here, the first to third air spring dampers 58, 60, 62 are the same so that the respective elastic coefficients can be set to arbitrary values according to the air pressures supplied to them. Configured,
Since the respective configurations are well known, description thereof will be omitted here.

Further, as shown in FIG. 4, the valve mechanism 22B constituting the above-mentioned air supply mechanism 16 has the first to third air spring type dampers 58, 60, which are provided in the rear shock absorber 14B. First to third control valves 64, 66, 68 provided corresponding to 62 are provided. These first to third control valves 64, 66, 68 are connected to the above-mentioned control unit 24, and drive-controlled by them. Here, each control valve 64, 66, 68
Is a connection position for increasing the internal pressure by connecting the air cylinder chambers of the corresponding air spring dampers 58, 60, 62 to the accumulator 20 and the air cylinder chambers of the corresponding air spring dampers 58, 60, 62. It is configured to be movable between a closed position in which it is closed to hold the internal air pressure and an open position in which the air cylinder chambers of the corresponding air spring dampers 58, 60, 62 are opened to the atmosphere to lower the internal pressure. On the basis of a control signal from the control unit 24, it is moved and driven to a predetermined position and held at that position. The control unit 24 is set to control the control amounts of the first and second control valves 64 and 66 to be the same so as to maintain the left-right balance of the vehicle body 12.

The general operation of the rear shock absorber 14B will be described below. That is, in the normal traveling mode other than the rough road traveling mode in which the vehicle travels on the rough road at a low speed,
And the control valves 64 and 66 corresponding to the second air spring type dampers 58 and 60 are both brought to the closed position, and perform a predetermined elastic function while being maintained at a predetermined air pressure. The control valve 68 corresponding to the centrally located third air spring damper 62 is brought to the open position,
As a result, the air cylinder chamber of the third air spring damper 62 is opened to the atmosphere and its elastic function is lost, that is, the elastic support is not provided. As a result,
In the normal traveling mode, the front portion of the vehicle body 12 has the first and second coil springs 5 located at both ends.
4, 56 and the first and second air spring type dampers 58,
By 60, the vertical movement can be buffered. In other words, in this normal traveling mode, the roll rigidity of the vehicle body 12 is maintained high.

In the first embodiment, the air pressure acting on the first and second air spring dampers 58 and 60 is controlled in the state where the normal traveling mode is set, which will be described in detail later. By adjusting the vehicle height, the target vehicle height (H1) is set to a higher vehicle height (H1H) when driving at low speed, and a lower vehicle height (H1L) is set when driving at high speed. Is set so that

On the other hand, in the above-mentioned rough road traveling mode, the control valves 64 and 66 corresponding to the first and second air spring dampers 58 and 60 are once brought to the open position, and the first and second control valves 64 and 66 are once brought to the open position. The air spring type dampers 58, 60 are brought to the closed position after lowering their elastic coefficients, and in the state where they are maintained at a predetermined low air pressure, they perform a weak elastic function and are located at the center. The control valve 68 corresponding to the third air spring damper 62 is brought to the connection position, is set to a predetermined air pressure, is then brought to the closed position, and is maintained at a predetermined high air pressure. , It becomes a state of fulfilling a stronger elastic function. As a result, in this rough road traveling mode, the front portion of the vehicle body 12 is mainly supported by the central third air spring type damper 62, and a large amount of lateral roll is allowed. In other words, the roll rigidity of the vehicle body 12 is set to be low in this rough road traveling mode.

In the first embodiment, as will be described later in detail, a target vehicle height (H2) higher than that in the normal traveling mode is set in the state in which the rough road traveling mode is set. The first to third air spring dampers 58, 6 are set so as to reach the target vehicle height (H2).
The air pressure of 0,62 will be set. Further, in the first embodiment, as described above, the wat link is used as the lateral link 44, and therefore, the support shaft 46 for swingably supporting the swing link 48 has the axle housing 34 in advance. Of the third air spring type damper 62, since the lower end of the third air spring type damper 62 is pivotally attached to the support shaft 46. It does not require a special bracket for attaching the shaft to the axle housing 34, and can improve its mountability, that is, the assemblability.

Next, the control procedure for controlling the rear shock absorber 14B in the above-mentioned control unit 24 will be described with reference to the flow charts of FIGS. 5 to 7 and the diagram of FIG. First, as shown in FIG. 5, this control procedure is started by turning on an ignition switch (not shown). Then, in step S10, first, all data and stored contents are initialized. In this initialization operation, all flags are reset to "0". After that, in step S12, the current traveling vehicle speed is read based on the vehicle speed information (V) from the vehicle speed sensor 26 and is temporarily stored in a memory (not shown). Further, in the subsequent step S14, the current vehicle height of the vehicle body 12 is read based on the vehicle height information (H) from the vehicle height sensors 28A and 28B and is temporarily stored in a memory (not shown). Further, in step S16, the inhibitor switch 32
Based on the drive mode setting signal from, the drive mode currently set in the auxiliary transmission is read and temporarily stored in a memory (not shown).

Thereafter, in step S18, it is determined whether or not the above-mentioned manual switch 30 is turned on. If NO is determined in step S18, that is, if the normal drive mode is manually set in the manual switch 30, the 4L signal is output from the auxiliary transmission inhibitor switch 32 in step S20. It is determined whether or not it is output. When it is determined NO in step S20, that is, when it is determined that the low speed four-wheel drive mode is not set in the auxiliary transmission, in combination with the determination of NO in step S18 described above. Then, it is determined that the normal traveling mode is set, and the process proceeds to step S22 and subsequent steps shown in FIG.

When the execution of the normal traveling control procedure is started, as shown in FIG. 6, first, at step S22,
The third control valve 68 is drive-controlled to the open position. As a result, the third air spring damper 62 opens the air in the air cylinder chamber to the atmosphere, and is in a state where it cannot substantially exert its elastic function. As a result, the vehicle body 12 has the first and second air spring dampers 58, 6 located at both ends.
It will be supported by 0, the number of rolls will be reduced, and running stability will be secured.

Then, in step S24, the target vehicle height (H1) corresponding to the detected vehicle speed is read. Incidentally, this first
In the embodiment of the present invention, as shown in FIG. 8, when the vehicle speed is increased, the low speed region is set below 70 km / h, the low speed region is set below that, and the high speed region is set above it. With 60 km / h as the boundary, the low speed area below that,
The high speed area is set above that. Then, as the target vehicle height (H1) for the normal traveling mode, the detected vehicle speed (V)
Is determined to be in the low speed range, a higher vehicle height (H1H) is set, while if it is determined that the detected vehicle speed (V) is in the high speed range, a lower vehicle height (H1L) is set. ) Is set. In this way, by keeping the vehicle height in the high-speed region low, traveling stability during high-speed traveling can be further ensured.

Thereafter, in step S26, it is determined whether or not the detected vehicle height (H) has reached the target vehicle height (H1) for the normal traveling mode. If NO in step S26, that is, if it is determined that the detected vehicle height (H) has not reached the target vehicle height (H1), the first timer A is set in the subsequent step S28.
It is determined whether "1" is set in the flag F (TA) indicating the starting state of the. In this step S28, N
If it is determined to be O, that is, if it is determined that the first timer A has not been activated yet, the first timer A is activated in step S30. Incidentally, in the first embodiment, the first timer A is configured as a countdown timer, and upon activation thereof, the countdown operation is sequentially started from the initially set time. Then, in step S32, the flag F (T
A) is set to "1" to indicate that the first timer A has been started, and the subsequent step S34 is executed.

On the other hand, in step S28 described above, Y
If it is determined to be ES, that is, if the flag F (TA) is set to "1" and it is determined that the first timer A has already been started and is currently executing the countdown, the step proceeds. The process directly proceeds to step S34 without executing S30 and step S32. In step S34, it is determined whether or not the count value of the first timer A has reached "0", and if the determination is NO, that is, the first timer A has not yet reached "0". If it is determined to be true, the process returns to step S24 to execute the control procedure below. On the other hand, when YES is determined in step S34, that is, even when the time set by the first timer A has elapsed, the detected vehicle height (H) has not reached the target vehicle height (H1). If it is determined that
By the following control operation, the first and second control valves 64 and 66 are driven to drive the first and second air spring dampers 58 and 6
The vehicle height adjustment operation is executed by changing the air pressure of 0. That is, if YES is determined in step S34, the flag F (TA) is reset to "0" in step S36, and the detected vehicle height (H) approaches the target vehicle height (H1) in subsequent step S38. To
The first and second control valves 64 and 66 are drive-controlled.

That is, although details are not shown in this step S38, if H <H1, the first
And the second control valves 64 and 66 are brought to the connection position for a predetermined time, and compressed air is introduced from the accumulator 20 into the air cylinder chambers of the first and second air spring dampers 58 and 60 to raise the vehicle height. After that, the first and second control valves 64 and 66 are moved to the closed position,
Maintain its air pressure. On the other hand, when H> H1, the first and second control valves 64 and 66 are brought to the open position for a predetermined time, and the air is released from the air cylinder chambers of the first and second air spring dampers 58 and 60. To lower the vehicle height, and then the first and second control valves 6
4, 66 are moved to the closed position to maintain the air pressure.

In this way, the first and second control valves 64,
After the drive control of 66, the step S shown in FIG.
Returning to 12, the subsequent control procedure is executed again. On the other hand, if YES in step S26 described above, that is, if it is determined that the detected vehicle height (H) substantially matches the target vehicle height (H1), the first timer A
Even during the countdown operation of step S40, the process proceeds to step S40, where the flag F (TA) is reset to "0",
The process returns to step S12. In this way, a series of normal traveling control procedures is ended, and the control procedure is returned immediately after the initialization operation.

On the other hand, in step S18 described above, Y
If judged as ES, that is, the manual switch 30
Is turned on and it is determined that the rough road traveling mode is manually set, the process proceeds to step S42,
Here, it is determined whether or not the detected vehicle speed (V) is equal to or higher than a predetermined minimum vehicle speed (V ₀ ). And this step S42
If YES is determined, that is, if the vehicle is currently traveling at the minimum speed (V ₀ ) or more, even if the rough switch traveling mode is set by the manual switch 30. , It is not in a rough road running state, but on the contrary, by setting this bad road running mode,
Since the high-speed running state cannot be maintained safely, the process jumps to step S20 described above to forcibly return the control procedure to the normal running side.

If NO is determined in step S42, that is, the vehicle is currently at the minimum speed (V ₀ ).
If it is determined that you are traveling at a slower speed than
Go to step S44, where last step S18
It is determined whether or not the manual switch 30 has been turned off by the determination procedure in. Y in this step S44
If judged as ES, that is, the manual switch 30
If it is determined that the switch has just been switched from off to on, the process proceeds to step S46, where the third control valve 68 is drive-controlled, and the third control valve 68 is controlled by the vehicle body 1.
The buffer operation of the front part of 2 can be dominantly executed. In this step S46, specifically, the third control valve 68 is moved to the connecting position for a predetermined time, compressed air is supplied from the accumulator 20, and the air cylinder chamber of the third air spring damper 62 is operated. The pressure is set to a predetermined value, and then the third control valve 68 is moved to the closed position to maintain the air pressure in this air cylinder chamber. In this way, the third air spring damper 62 is brought into a state in which it is possible to execute the cushioning operation with a predetermined elastic coefficient. In this way, after the third control valve 68 is drive-controlled in step S46, the process proceeds to the subsequent step S50.

In step S44 described above, N
If it is judged to be O, that is, if it is judged that the manual switch 30 is continuously set to the ON state, step S46 has already been executed and the third control valve 6
Since the drive control of step 8 has been completed, step S46 is skipped and the process directly goes to step S50. On the other hand, if YES in step S20 described above, that is, if it is determined that the 4L signal indicating that the low speed side four-wheel drive mode has been set is output from the auxiliary transmission inhibitor switch 32. Is step S48
Then, it is determined whether or not the 4L signal was output in the determination procedure in step S20 at the previous time. If it is determined NO in step S48, that is, if it is determined that the low-speed four-wheel drive mode has just been set, the process jumps to step S46 described above to control the drive of the third control valve 68. To execute. Further, if YES is determined in this step S48, that is, if it is determined that the low speed four-wheel drive mode is continuously set, step S46 is already executed and the third control valve 68 is executed. Since it is determined that the drive control of step S46 has been completed, step S46 is skipped and the process directly jumps to step S50.

That is, in the first embodiment, when it is determined that the vehicle is traveling at a low speed in the state where the bad road traveling mode is manually set via the manual switch 32, and in the auxiliary transmission, When either of the case where the low speed side four wheel drive mode is set is established,
The introduction of compressed air to the third air spring damper 62 is allowed only when the respective conditions are satisfied. Then, the compressed air is introduced into the third air spring damper 62 in this way, and the cushioning operation can be executed with a predetermined elastic coefficient. As will be described later, the first and second air located at both ends are compressed. By setting the elastic coefficients of the spring type dampers 58 and 60 to be small, the vehicle body 12 is mainly supported by the central third air spring type damper 62, so that the roll rigidity becomes extremely small. As a result,
Lateral wobbling of the vehicle body 12 is prevented, the suspension stroke is effectively withdrawn, and both wheels RL, R
The ground load of each R is stabilized.

As described above, by driving and controlling the third control valve 68 in step S46, the front portion of the vehicle body 12 is mainly supported by the third air spring damper 62, so that the first and second parts are maintained. Unless the air pressure of the second air spring type dampers 58 and 62 is adjusted, the vehicle height will be unnecessarily increased. In order to prevent such an unnecessary increase in vehicle height, the vehicle height adjustment operation associated with the operation of the third air spring damper 62 is executed in the control procedure starting from step S50.

In this vehicle height adjusting operation, first, in step S50, the target vehicle height (H) for the rough road traveling mode is set.
It is determined whether the detected vehicle height (H) has reached 2). The target vehicle height (H2) in the rough road traveling mode is higher than the target vehicle height (H1) in the normal traveling mode described above, in other words, higher than the higher target vehicle height (H1H) in the low speed region. It is set to ensure that it can run on rough roads.

If NO is determined in step S50, that is, the detected vehicle height (H) is still the target vehicle height (H
When it is determined that the value has not reached 2), it is determined in a succeeding step S52 whether "1" is set in the flag F (TB) indicating the activation state of the second timer B. If NO in step S52, that is, if it is determined that the second timer B has not been started yet, the second timer B is set in step S54.
Timer B is started. Incidentally, in the first embodiment, the second timer B is configured as a countdown timer, and upon activation thereof, the countdown operation is sequentially started from the initially set time. Then, in step S56, the flag F (TB) is set to "1" to indicate that the second timer B is activated, and the subsequent step S58 is executed.

On the other hand, in step S52 described above, Y
If it is determined to be ES, that is, if the flag F (TB) is set to "1" and it is determined that the second timer B has already been started and the countdown is currently being performed, the step proceeds. The process directly proceeds to step S58 without executing S54 and step S56. In this step S58, it is judged whether or not the count value of the second timer B has become "0", and if the result is NO, that is, the second timer B has not yet become "0". If it is determined to be true, the process returns to step S50 to execute the control procedure below. On the other hand, if YES is determined in step S58, that is, even if the time set by the second timer B has elapsed, the detected vehicle height (H) has not reached the target vehicle height (H2). If it is determined that
By the following control operation, the first and second control valves 64 and 66 are driven to drive the first and second air spring dampers 58 and 6
The vehicle height adjustment operation is executed by changing the air pressure of 0. That is, if YES in step S58, the flag F (TB) is reset to "0" in step S60, and the detected vehicle height (H) approaches the target vehicle height (H2) in subsequent step S62. To
The first and second control valves 64 and 66 are drive-controlled.

That is, although details are not shown in this step S62, if H <H2, the first
And the second control valves 64 and 66 are brought to the connection position for a predetermined time, and compressed air is introduced from the accumulator 20 into the air cylinder chambers of the first and second air spring dampers 58 and 60 to raise the vehicle height. After that, the first and second control valves 64 and 66 are moved to the closed position,
Maintain its air pressure. On the other hand, when H> H2, the first and second control valves 64 and 66 are brought to the open position for a predetermined time, and the air is released from the air cylinder chambers of the first and second air spring dampers 58 and 60. To lower the vehicle height, and then the first and second control valves 6
4, 66 are moved to the closed position to maintain the air pressure.

In this way, the first and second control valves 64,
After the drive control of 66, the step S shown in FIG.
Returning to 12, the subsequent control procedure is executed again. On the other hand, if YES in step S50 described above, that is, if the detected vehicle height (H) substantially matches the target vehicle height (H2), the second timer B
Even during the countdown operation of, the process proceeds to step S64, where the flag F (TB) is reset to "0",
The process returns to step S12. In this way, the series of rough road traveling control procedures is ended, and the control procedure is returned immediately after the initialization operation.

As described in detail above, by constructing the suspension devices 10B, 10B in the first embodiment, that is, by simply providing the air spring type damper 62 for supporting the central portion of the vehicle body, it is extremely simple. By adopting the configuration, it is possible to reduce the fluctuation of the ground load of the left and right wheels when traveling on a rough road as much as possible while improving the running performance on a rough road while being inexpensive. It goes without saying that the present invention is not limited to the configuration of the first embodiment described above, and can be variously modified without departing from the scope of the present invention.

For example, in the above-described first embodiment, the suspension device of the present invention is applied to a four-wheel drive vehicle, but the present invention is not limited to such a configuration. It can also be applied to two-wheel drive vehicles such as rear-wheel drive vehicles and forward-drive vehicles. In this case, needless to say, the suspension device of the present invention is applied to the driving side.

Further, in the above-mentioned first embodiment,
As a reaction force generating means for generating a reaction force against the biasing force of the shaft support of the Wattlink type lateral link to the axle housing, the air pressure in the cylinder chamber can be made variable, in other words, the respective elastic coefficients can be made variable. Although the third air spring damper configured so as to be capable of performing the above is used, the present invention is not limited to such a configuration, and is shown as a second embodiment in FIG. Alternatively, a torsion spring may be used.

The configuration of the second embodiment of the suspension device according to the present invention will be described below with reference to FIG. In the following description, the same parts as those in the first embodiment described above will be designated by the same reference numerals and the description thereof will be omitted. That is, the suspension device 70 of the second embodiment
As shown in FIG. 9, the respective elastic coefficients of the first and second air spring type dampers 58, 60 are set in a variable state as in the first embodiment described above. As a reaction force generating means for generating a reaction force against the biasing force of the shaft link of the Watt-link type lateral link 44 to the axle housing 34, a torsion spring 72 having a fixed elastic coefficient is provided. Has been.

The torsion spring 72 has a central portion wound around a support shaft 46 which swingably supports the swing link 48 on the axle housing 34, one end of which is hooked on the axle housing 34 and the other end of which swings. It is attached in a state of being hooked on the moving link 48. That is, in the second embodiment, the torsion spring 72 serving as the reaction force generating means causes lateral force to act on the vehicle body so that the swing link 48 swings around the support shaft 46 in the water link type lateral link 44. It is configured to generate a reaction force that opposes the biasing force that is about to move. In other words, the torsion spring 72 is configured to exert an elastic force in the direction of increasing the roll rigidity of the vehicle body when a lateral force acts on the vehicle body.

That is, in the second embodiment, the first
The elastic coefficients of the second air spring type dampers 58 and 60 are set to be the same. Therefore, when the normal traveling mode is set and the elastic coefficients of the first and second air spring dampers 58 and 60 located at both ends are set to predetermined values, the lateral force is applied to the vehicle body. When the action is performed, the torsion spring 72 generates a spring force, and the roll rigidity of the vehicle body 12 depends on the elastic coefficient of the torsion spring 72 and the first and second air spring type dampers 58, 60 located at both ends. The elastic modulus of the roll is defined in a combined state, and as a result, the roll rigidity is set high. On the other hand, when the rough road traveling mode is set, the elastic moduli of the first and second air spring dampers 58 and 60 located at both ends are controlled so as to be reduced, and as a result, the roll rigidity of the vehicle body 12 is reduced. Is
The torsion spring 72 located in the center acts predominantly, and as a result, the roll rigidity is set low.

By constructing the second embodiment in this way, the air pressures of the first and second air spring type dampers 58, 60 are made variable, and the Wattlink type lateral link 44 is used.
A torsion spring 72 for restricting the swinging deviation of the swinging link 48 is provided and the air pressures of the first and second air spring type dampers 58, 60 are controlled, so that the roll rigidity is improved in the normal running state. It is possible to set the roll rigidity higher and set the roll rigidity lower when the vehicle is running on a rough road.

Further, in the above-mentioned second embodiment,
It has been described that the torsion spring 72 is provided as a reaction force generating means for generating a reaction force against the biasing force of the shaft fulcrum of the watlink type lateral link to the axle housing, but the present invention is not limited to such a configuration. Alternatively, a pair of coil springs may be used as shown in FIG. 10 as the third embodiment.

The configuration of the third embodiment of the suspension device according to the present invention will be described below with reference to FIG. In the following description, the same parts as those of the first and second embodiments described above are designated by the same reference numerals, and the description thereof will be omitted. That is, in the suspension device 74 of the third embodiment, as shown in FIG. 10, the elastic coefficients of the first and second air spring dampers 58, 60 are the same as those of the first embodiment described above.
The variable state is set as in the second embodiment.
Further, as a reaction force generating means for generating a reaction force against the biasing force of the shaft link of the Watt-link type lateral link 44 to the axle housing 34, a pair of coil springs 76 whose elastic coefficients are set in a fixed state, 78 is provided.

More specifically, as shown in FIG. 10, the swing link 48 which constitutes the water-link type lateral link 44 has a left-handed upper portion on the left side, which has a substantially triangular shape and extends leftward. The seat 80 is integrally formed. Also,
A substantially triangular right receiving seat portion 82 extending rightward is integrally formed at a lower portion on the right side of the swing link 48. A left coil spring 76 is provided between the left receiving seat portion 80 and the base end portion of the left link 50, and between the right receiving seat portion 82 and the base end portion of the right link 52. At the right, a coil spring 78 on the right side is provided.
Since the pair of coil springs 76 and 78 are attached in this manner, the pair of coil springs 7
6, 78 can be equivalently replaced with the torsion spring 72 in the above-mentioned second embodiment, and in this third embodiment, the same effect as in the second embodiment can be achieved. become.

[0055]

As described in detail above, the suspension system for a vehicle according to the present invention includes an axle housing having a shaft for connecting left and right wheels to each other, and left and right end portions of the axle housing and the left and right sides of the vehicle body. Cushioning means for buffering the vertical movement between the respective parts and a portion extending substantially along the vehicle width direction, the center part of which is rotatably supported by the axle housing, and both ends thereof are connected to the vehicle body. It is characterized by comprising a Wattlink type lateral link and a reaction force generating means for generating a reaction force against the deviation of the shaft fulcrum of the Watlink type lateral link to the axle housing.

Further, in the vehicle suspension device according to the present invention, the buffering means is provided on both sides of the axle housing and elastically supports both sides of the vehicle body in the vehicle width direction. The air spring type damper, and the reaction force generating means has a third air spring type damper interposed between the vehicle body and the shaft fulcrum of the water link type lateral link to the axle housing. Is characterized by.

Further, in the vehicle suspension device according to the present invention, the Watt-link type lateral link is pivotally supported at the central portion of the axle housing, and the third air-spring type damper is provided in the vehicle width of the vehicle body. It is characterized by elastically supporting the central part in the direction. Further, in the vehicle suspension device according to the present invention, the first to third cushioning means are respectively set to have variable air pressures, and the respective air pressures of the first to third air spring dampers are controlled. It is characterized by being variably controlled by means.

In the vehicle suspension device according to the present invention, the control means sets the air pressure of the third air spring damper to substantially zero in the normal traveling mode and in the rough road traveling mode. It is characterized by controlling so as to maintain a predetermined value. Further, in the vehicle suspension device according to the present invention, the control means sets the air pressure of the third air spring damper to substantially zero in the normal traveling mode, and the first and second air The air pressure of the formula damper is set to a first predetermined value, and the air pressure of the third air spring damper is maintained at a second predetermined value in a bad road traveling mode, and the first and second air spring types are also set. It is characterized by controlling to reduce the air pressure of the damper.

Further, in the vehicle suspension device according to the present invention, the Watt-link type lateral link has a swing link whose central portion is pivotally supported by the axle housing, and one end of the swing link. One link that is pivotally supported, extends in one direction along the vehicle width direction, and has the other end pivotally supported by the vehicle body, and one end that pivots to the other end of the swing link. It is characterized in that it is provided with another link that is freely rotatably supported, extends to the other along the vehicle width direction, and has the other end rotatably rotatably supported by the vehicle body.

Further, in the vehicle suspension device according to the present invention, the reaction force generating means is interposed between the other end of the swing link and the one link, and elastically supports both. One of the springs and the other spring interposed between one end of the swing link and the other link and elastically supporting both of them are provided.

In the vehicle suspension device according to the present invention, the swing link includes a shaft portion fixed to the axle housing, and a link body rotatably attached to the shaft portion. The reaction force generating means includes a torsion spring wound around the shaft portion, one end of which is hooked to the axle housing and the other end of which is hooked to the link body.

Therefore, according to the present invention, it is possible to provide a suspension device for a vehicle capable of preventing the fluctuation of the ground contact load during traveling on a rough road. Further, according to the present invention, it is possible to provide a suspension device for a vehicle, which does not require an additional component such as a bracket and can improve the mountability.

[Brief description of drawings]

FIG. 1 is a side view schematically showing the configuration of a first embodiment of a vehicle suspension device according to the present invention.

FIG. 2 is a rear view showing the configuration of the suspension device in detail.

FIG. 3 is a side view showing a mounted state of a third air spring damper.

FIG. 4 is a front view schematically showing an air circuit configuration of a rear suspension device.

[Fig. 5]

[FIG. 6]

FIG. 7 is a flow chart showing a control procedure of the suspension device in the control unit according to the first embodiment.

FIG. 8 is a diagram showing a relationship between a detected speed and a target vehicle height in a normal traveling mode.

FIG. 9 is a front view schematically showing the configuration of the second embodiment of the vehicle suspension device according to the present invention.

FIG. 10 is a front view schematically showing the configuration of a third embodiment of the vehicle suspension device according to the present invention.

[Explanation of symbols]

10 Suspension Device (First Embodiment), 10A Front Suspension Device, 10B Rear Suspension Device, 12 Car Body, 14A Front Damper, 14B Rear Damper, 16 Air Supply Mechanism, 18 Air Pump, 20 Akymulator, 22A Front side valve mechanism, 22B Rear side valve mechanism, 24 Control unit, 26 Vehicle speed sensor, 28A Front side vehicle height sensor, 28B Rear side vehicle height sensor, 30 Manual switch, 32 Inhibitor switch, 34 Axle housing, 36 Left upper link, 38 left lower link, 40 right upper link, 42 right lower link, 44 wat link type lateral link, 46 support shaft, 48 swing link, 50 left link, 52 right link, 54; 56 coil spring, 58 1st of Impact mechanism (first air spring damper), 60 Second shock absorbing mechanism (second air spring damper), 62 Third shock absorbing mechanism (third air spring damper), 64 First control valve 66 second control valve, 68 third control valve, 70 suspension device (second embodiment), 72 torsion spring, 74 suspension device (third embodiment), 76; 78 coil spring, 80 left receiving seat, 82 right receiving seat.

Claims (9)

[Claims] 1. An axle housing in which a shaft for connecting left and right wheels to each other is built-in, cushioning means for cushioning vertical movement between left and right end portions of the axle housing and left and right portions of a vehicle body, and a vehicle width. A lateral link that extends along the direction and is rotatably supported by the axle housing at its central portion, and has both ends connected to the vehicle body, and a watlink type lateral link to the axle housing. A suspension device for a vehicle, comprising: a reaction force generating means for generating a reaction force against a deviation of a shaft fulcrum. 2. The cushioning means includes first and second air spring dampers that are provided on both sides of the axle housing and elastically support both sides of the vehicle body in the vehicle width direction, respectively. 2. The vehicle according to claim 1, wherein the generating means includes a third air spring type damper interposed between a vehicle body and a shaft fulcrum of the wat-link type lateral link to the axle housing. Suspension device. 3. The Watt-link type lateral link comprises:
The suspension of the vehicle according to claim 2, wherein the third air spring damper is supported by the center of the axle housing, and elastically supports the center of the vehicle body in the vehicle width direction. apparatus. 4. The first to third buffering means, respectively.
The air pressure is variably set, and the air pressure of each of the first to third air spring dampers is
3. The control means is variably controlled.
Suspension device for vehicle according to item 1. 5. The control means sets the air pressure of the third air spring damper to substantially zero in the normal traveling mode and maintains the air pressure at a predetermined value in the rough road traveling mode. The vehicle suspension device according to claim 4, wherein the suspension device is a vehicle suspension device. 6. The control means sets the air pressure of the third air spring damper to substantially zero and sets the air pressures of the first and second air dampers to the first in the normal traveling mode. Set to a predetermined value, and in the rough road driving mode, the third
6. The air pressure of the air spring type damper is maintained at a second predetermined value, and the air pressures of the first and second air spring type dampers are controlled to be reduced.
Suspension device for vehicle according to item 1. 7. The Watt-link type lateral link comprises:
A swinging link whose central portion is axially supported by the axle housing, one end of which is pivotally supported at one end of the swinging link, extends in one direction along the vehicle width direction, and has the other end in the vehicle body. One end of the swing link is rotatably supported, and the other end of the swing link is rotatably supported at one end thereof, extends along the vehicle width direction to the other end, and the other end is rotated to the vehicle body. The suspension device for a vehicle according to claim 1, further comprising another link that is freely supported. 8. The reaction force generating means is interposed between the other end of the swing link and the one link, and one spring elastically supporting both is provided, and one end of the swing link. The suspension device for a vehicle according to claim 7, further comprising: another spring interposed between the other link and the other link and elastically supporting the both. 9. The swing link includes a shaft portion fixed to the axle housing, and a link body rotatably attached to the shaft portion, and the reaction force generating means is provided on the shaft portion. 8. The suspension device for a vehicle according to claim 7, further comprising a torsion spring wound around and hooked at the axle housing at one end and hooked at the link body at the other end.