JP3019312B2 - Torsion bar suspension system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle suspension, and more particularly to a torsion bar type suspension device capable of adjusting a vehicle height.

[Conventional technology]

Conventionally, in a torsion bar type suspension device having a torsion bar which is supported on one end of a suspension arm and the other end of the vehicle body so as not to rotate, for example,
As shown in Japanese Patent Application Laid-Open No. 61-75006, in a torsion bar type suspension, it is possible to adjust the vehicle height by displacing an anchor arm non-rotatably attached to an end of the torsion bar on the vehicle body side by a telescopic mechanism. A known torsion bar type suspension device is known.

[Problems to be solved by the invention]

However, in the above-described conventional suspension device, although the vehicle height can be adjusted, the spring constant of the torsion bar cannot be controlled.

For this reason, for example, when the vehicle height is increased to avoid interference between a convex portion due to a rut on a road surface and the vehicle body, since the center of gravity of the vehicle is high, the roll or pitching of the vehicle body also increases. is there.

Further, for example, when the vehicle height is lowered during high-speed running, it is desired to increase the spring constant from the viewpoint of running stability.

[Means for solving the problem]

The present invention has been made in view of the above, and has a suspension arm supported to be swingable with respect to a vehicle body, a torsion bar having one end connected to the suspension arm, and the other end connected to the vehicle body so as not to rotate. And a torsion bar applying mechanism interposed between the torsion bar and the vehicle body and capable of applying a torsional moment to the torsion bar.

[Action]

According to the present invention, when the torsional moment is applied to the torsion bar by the torsional moment applying mechanism, the other end of the torsion bar is non-rotatably connected to the vehicle body. Move
The suspension arm connected to the same end swings with respect to the vehicle body to adjust the vehicle height. Further, since the torsion amount of the torsion bar also changes according to the application of the torsional moment, the spring constant of the torsion bar is adjusted simultaneously with the adjustment of the vehicle height.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.

In FIG. 1, reference numeral 2 generally indicates a front suspension according to the present embodiment, 4 and 6 are upper and lower arms swingably supported by a body frame (not shown), and 8 is a ball having upper and lower ends respectively. This is a knuckle pivotally connected via joints 10 and 12, and the upper arm 4, the lower arm 6, and the knuckle 8 constitute a so-called double wishbone type suspension.

14 is the first torsion bar 16 and the second torsion bar 18
Is a torsion bar. In particular, as is apparent in FIG. 2, the front end of the first torsion bar 16, that is,
Spline 16a formed at one end of torsion bar 14
Is non-rotatably fitted to an anchor 22 having a spline 22a on the inner periphery fixed to the lower arm 6 by bolts 20,20. In FIG. 2, reference numeral 24 denotes the lower arm 6.
And 26 is a vehicle body member that supports the bush 24. A spline 16b formed at the rear end of the first torsion bar 16 has a first anchor arm 28.
Sleeve 30 having a spline 30a on the inner periphery fixed to the sleeve 30
Are non-rotatably fitted. 2nd torsion bar 18
Is the first torsion bar, as is apparent in FIG.
The first torsion bar 16 has a spline 18a which is non-rotatably engaged with a spline 16b of the first torsion bar 16 at its rear end inner periphery. Also, the front end of the second torsion bar 18, that is, the torsion bar 14
A sleeve 34 having a spline 34a on the inner periphery fixed to the second anchor arm 32 is non-rotatably fitted to a spline 18b formed on the outer periphery of the other end of the arm. In FIG. 3, reference numeral 36 denotes the first torsion bar 16 and the sleeve 34.
A dust cover 38 is provided over the second torsion bar 18 and the sleeve 30.

As shown in FIG. 4, the second anchor arm 32 has its sleeve 34 positioned in a recess 40a formed on the lower surface of the cross frame 40 of the vehicle body, and further formed on the lower surface of the distal end of the arm 32. An anchor bolt 42 is provided between the recess 32a formed and the recess 40b formed on the upper surface of the cross frame 40. More specifically, the anchor bolt 42 is inserted through the contact 44 in contact with the recess 32a, the anchor arm 32, the cross frame 40, and the contact 46 in contact with the recess 40b in this order, and a nut 48 is screwed into its shaft. The second torsion bar 18 and the first torsion bar 16 are configured to increase the torsional reaction force by tightening the nut 48.

The first anchor arm 28 is basically connected to the vehicle body cross frame 50 by a structure similar to the second anchor arm 32, as shown in FIG. Telescopic mechanism at the part corresponding to
54 are built in. Then, in the present embodiment, the first anchor arm 28 and the extension mechanism 54 constitute a torsional moment applying mechanism.

The telescopic mechanism 54 includes a cylinder 58 attached to the cross frame 50 via a bracket 56, a piston 60 fitted in the cylinder 58, and an upper end connected to the piston 60 via a ball joint 62. Has a connecting rod 66 connected to the distal end of the first anchor arm 28 via a connecting pin 64. And while the chamber 68 defined by the cylinder 58 and the piston 60 is filled with oil,
The chamber 68 communicates with an accumulator 72 through a passage 70. The accumulator 72 has the same function as a known accumulator, and includes a cylinder 74 and the same cylinder.
The cylinder includes a free piston 76 which is fitted in 74 and partitions the cylinder into a chamber 78 and a chamber 80. The chamber 78 is filled with oil, and the chamber 80 is filled with a gas such as nitrogen gas. In FIG. 5, reference numeral 82 denotes a drain plug provided at the bottom of the accumulator 72, 84 denotes a joint that connects the passage 70 to the accumulator 72 by a stopper 86, and 88 denotes a joint that connects the passage 70 to the cylinder 58 by a stopper 90. It is. The chamber 68 is connected via a passage 92 to a hydraulic supply / discharge device to be described later.

The suspension structure shown in FIGS. 1 to 5 is a front suspension disposed on the right side of the vehicle body. Although not shown, a front suspension having a similar structure is symmetrically provided on the left side of the vehicle body.

6 and 7 show a rear suspension, in which reference numeral 100 denotes a rear axle housing that is swingably supported on the vehicle body via left and right trailing arms 102 and 104, and 106 and 106 denote axle housings 100, respectively. Is a lower spring bearing fixed on both left and right ends of the lower spring. Each lower spring support 10
The space between 6,106 and the vehicle body is configured as shown in FIG. That is, a bracket 108 attached to a body frame (not shown), a cylinder 110 fixed to the bracket 108, and a piston fitted in the cylinder 110
112, an upper spring receiver 114 fixed to the piston 112,
It comprises a coil spring 116 contracted between the upper spring support 114 and the lower spring support 106. A chamber 118 defined by the cylinder 110 and the piston 112
Is connected to a hydraulic supply / discharge device to be described later. Further, although not shown, a shock absorber is provided between the trailing arms 102 and 104 or the axle housing 100 and the vehicle body, and the compressed state of the coil spring 116 is maintained even when the shock absorber extends its maximum amount. It is configured as follows. In FIG. 7, reference numeral 122 denotes a joint for connecting the passage 120 to the cylinder 110 by a stopper 124, and reference numeral 126 denotes a rubber fixed to the lower surface of the upper spring receiver 114 and restricting the maximum stroke of the lower spring receiver 106 with respect to the upper spring receiver 114. Bump stopper.

FIG. 8 shows the chambers in the cylinders 58 on the front side described above.
68, chamber 78 of each accumulator 72 and each cylinder on the rear side
FIG. 3 is an explanatory diagram showing a relationship between a chamber 118 in a 110 and a hydraulic supply / discharge device. In FIG. 8, reference numeral 130 denotes a pump driven by an electric motor 132. The pump 130 is of a type in which the discharge direction is reversed according to the rotation direction of the motor 132. That is, when the motor 132 rotates in the direction A, the oil is sucked from the port 130a and discharged to the port 130b, and when the motor 132 rotates in the direction B, the oil is sucked from the port 130b and discharged to the port 130a. Type. The port 130a of the pump 130 is connected to the reservoir 136 via a check valve 134, and is also connected to the reservoir 136 via an orifice 138 in parallel with the check valve 134.
It is connected to the. The port 130b is connected to the reservoir 136 via the check valve 140. Check valve 134
And 140 have the function of permitting only oil flow from reservoir 136 to ports 130a and 130b, respectively.

The port 130b is connected to the chambers 68 via a control valve 142, a control valve 144, and a check valve 146. Control valve 142
Operates as a check valve that allows only the flow of oil from the port 130b to the control valve 144 when the pressure in the passage between the port 130a and the orifice 138 is less than a set pressure (for example, 3 kg / cm ² ). When the pressure in the passage to the orifice 138 is equal to or higher than the set pressure, the passage is opened to allow a flow of oil from the control valve 144 to the port 130b. The control valve 144 has a function of being opened when the pressure in the passage between the control valve 144 and the control valve 142 is lower than a set pressure (for example, 30 kg / cm ² ) and closed when the pressure is equal to or higher than the set pressure. The check valve 146 has a function of permitting only oil flow from the control valve 144 to the chambers 68,68. Further control valve 142
Is connected to the chambers 68, 68 via a check valve 148 and a control valve 150 which are in parallel with the control valve 144 and the check valve 146. Check valve 148 is controlled from control valve 150 to control valve 14.
It has a function that allows only the oil flow toward 2. The control valve 150 has a function of being closed when the pressure in the passage between the control valve 150 and the chambers 68 and 68 is lower than a set pressure (for example, 14 kg / cm ² ) and opened when the pressure is equal to or higher than the set pressure. .

Further, the control valve 142 is connected to the chambers 118 and 118 via an orifice 152 and a check valve 154, and the pressure in the passage between the orifice 152 and the check valve 154 is set to a set value (for example, 50 kg / cm ^2). The high-voltage switch 156 that is turned on when the value is less than the value () and turned off when the value is equal to or more than the set value is connected. The check valve 154 has a function of allowing only the flow of oil from the orifice 152 to the chambers 118 and 118. The control valve 142 is connected to the chambers 118 and 118 via an orifice 158 and a check valve 160 which are in a parallel relationship with the orifice 152 and the check valve 154, and is connected to a passage between the orifice 158 and the control valve 142. Is connected to a low pressure switch 162 which is turned off when the pressure in the passage is less than a set value (for example, 2 kg / cm ² ) and turned on when the pressure in the passage is equal to or more than the set value. Further, the control valve 142 is closed when the inside of the passage between the control valve 142 and the control valve 144 is less than a set value (for example, 75 kg / cm ² ) and opened when the inside of the passage is equal to or more than the set value. Is connected to the reservoir 136 via the.

FIG. 9 shows a circuit for controlling a motor 132 for driving the pump 130 shown in FIG. In FIG. 9, reference numeral 1
70 is a power supply, and 172 is a main switch connected to the power supply 170. The main switch 172 is also used as an engine key switch. A brake switch 174 is turned on when a brake pedal (not shown) is depressed.
Is connected to the main switch 172 and the brake switch 174
This switch is turned OFF by ON output. A vehicle speed sensor 178 turns ON when the vehicle speed is equal to or higher than a set vehicle speed (for example, 30 kg / h). A switch 180 is connected to the switch 176 and has a movable contact 186 for selecting one of the contacts 182 and 184. When the vehicle speed sensor 178 is turned off, the movable contact 186 contacts the contact 182.
The movable contact 186 contacts the contact 184 when the vehicle speed sensor 178 is ON. Reference numeral 188 denotes a manually operated selection switch having two movable contacts 190 and 192 interlocked with each other and corresponding contacts 194 and 196, respectively. When the movable contact 190 is in contact with the contact 194, the movable contact 192 is turned off. When the movable contact 192 is in contact with the contact 196, the movable contact 190 is not in contact with the contact 194 (when the high vehicle height is selected). In the changeover switch 180, the contact 182 is connected to the movable contact 192 of the selection switch 188, and the contact 184 is connected to the low-voltage switch 162. Select switch 188 has its movable contact 190 connected to switch 176 and its contact 194.
Is connected to the low-voltage switch 162, and its contact 196 is connected to the high-voltage switch 156. The high-voltage switch 156 and the low-voltage switch 162 are connected to the motor drive circuit 198, respectively.
The motor drive circuit 198 supplies power for driving the motor from the main switch 172, and switches the motor 132 in the direction of arrow A in FIG. From the oil)
When the ON signal is input from the low pressure switch 162 side, the motor 132 is rotated in the direction of arrow B in FIG. 8 (that is, the pump 130 discharges oil from its port 130a)
From either side of the high pressure switch 156 and the low pressure switch 162
The motor 132 is configured to stop when the ON signal is not output.

Next, the operation of the above-described suspension device will be described.

First, in the normal vehicle height, the front side rooms 68, 6
8 is set to 10 kg / cm ² and rear chambers 118 and 118 are 2 kg / cm
Set to ² . Now, the vehicle height is at the normal vehicle height,
When the main switch 172 and the switch 176 are turned on and the movable switch 192 is brought into contact with the contact 196 by operating the selection switch 188 to increase the vehicle height, the high-voltage switch 156 is turned on at this time. Circuit 198 rotates motor 132 of pump 130 in the direction of arrow A in FIG.
As a result, oil is discharged from the port 130b of the pump 130,
The chamber 68, via the control valve 142, the control valve 144 and the check valve 146,
While oil is supplied to 68, the vehicle height on the front side starts to increase, while oil is also supplied to the chambers 118, 118 via the control valve 142, the orifice 152, and the check valve 154, and the vehicle height on the rear side also starts to increase. Then, when the pressure in the passage between the control valve 142 and the control valve 144 reaches 30 kg / cm ² , the control valve 144 is closed and the front-side vehicle height adjustment is completed, and thereafter, the chamber 68, 68 Is stopped, and only the supply of oil to the chambers 118, 118 is continued. The control valve 150 is opened when the pressure in the passage between the control valve 150 and the check valve 146 becomes 13 kg / cm ² or more. However, since the check valve 148 exists, the control valve 150
No oil is supplied to the chambers 68, 68 via the. Room 118,1
When the supply of oil to 18 is continued and the pressure in the passage between the orifice 152 and the check valve 154 reaches 50 kg / cm ² , the high pressure switch 156 is turned off and the motor drive circuit 198 turns off the motor 1
The vehicle height adjustment on the rear side is also completed by stopping the vehicle 32, whereby the vehicle height is maintained at a high vehicle height.

Next, the operation of returning the vehicle height from the high vehicle height state to the normal vehicle height will be described.

In the high vehicle height state, the movable switch 190 is operated by operating the selection switch 188 to return the vehicle height to the normal vehicle height.
When the contact is brought into contact with 4, the low pressure switch 162 is ON at this time, so that the motor drive circuit 198 rotates the motor 132 of the pump 130 in the direction of arrow B in FIG.

At this time, since the control valve 142 is operating as a check valve, the pump 130 sucks oil from the reservoir 136 via the check valve 140 from the port 130b and discharges oil from the port 130a. Then, when the pressure in the passage between the port 130a and the orifice 138 rises and reaches 3 kg / cm ² , the control valve 142 is opened, and the oil in the chambers 118, 118 starts to be discharged, whereby the pressure in the chambers 118, 118 is reduced. And the vehicle height on the rear side starts to fall. When the pressure in the passage between the control valve 142 and the check valve 148 is less than 30kg / cm ^2, the check valve 148 is opened, oil in the chamber 68 also begins to be discharged, thereby chamber 68
The pressure inside the vehicle decreases, and the vehicle height on the front side also starts to decrease. Further, the pressure in the chambers 68, 68 decreases, and
When the pressure in the passageway between the lower side and 150 becomes less than 13 kg / cm ² , the control valve 150 is closed and the height reduction adjustment on the front side is completed, and thereafter the distribution of oil in the chambers 68 and 68 stops. Being room 118,118
Only the discharge of the oil inside is continued. When the pressure in the passage between the control valve 142 and the orifice 158 reaches less than 2 kg / cm ² , the low-pressure switch 162 is turned off and the motor drive circuit 19
8 stops the motor 132 and completes the rear-side vehicle height reduction adjustment, whereby the vehicle height is maintained at the normal vehicle height.

The front-side chambers 68, 68 and the accumulators 72, 72
If the front suspension makes a full stroke to the contraction side when the pressure in the same room 68, 68 is 10 kg / cm ² ,
The pressure in the chambers 68, 68 is set to increase to about 12 kg / cm ² . Therefore, even if the pressure in the chambers 68, 68 is 13 kg / cm ² immediately after performing the vehicle height reduction adjustment from the high vehicle height to the normal vehicle height as described above, the front suspension moves to the contraction side during traveling thereafter. Each time the pressure in the chambers 68, 68 rises to 13 kg / cm ² or more by the stroke, the control valve 150 is opened and the oil is sent out via the check valve 148. The internal pressure will settle down to about 10 kg / cm ² . Then, the check valve 14 is supplied by the delivered oil.
8 and the passage between the offices 158 (that is, chambers 118, 118
In this case, the low pressure switch 162 is turned on, and the motor drive circuit 198 rotates the motor 132 of the pump 130 to reduce the pressure in the passage by 2 k / cm ^2.
g / cm ² .

According to the above configuration, in the normal vehicle height state, the pressure in the front suspension chambers 68, 68 is kept at a relatively small pressure (about 10 kg / cm ² ).
Considering the torsion bars 16 and 18 and the pressure in the chambers 68, 68, the substantial spring constant at the front end of the first torsion bar 16 is also relatively small, so that good riding comfort can be obtained.
By operating the selection switch 188 to the high vehicle height side (contacting the movable contact 192 with the contact 196) when traveling on a road with deep ruts, the pressure in the front chambers 68, 68 is reduced to 30 kg / cm ^2.
In addition, the pressure in the rear chambers 118, 118 is increased to 50 kg / cm ² to increase the vehicle height, and the reaction force due to the pressure in the chambers 68, 68 acting on the rear end of the first torsion bar 16 is increased. Therefore, the substantial spring constant at the front end of the first torsion bar 16 (the spring constant as viewed from the lower arm 6) also increases. As a result, even if the vehicle height is increased and the center of gravity of the vehicle is increased, the spring constant is increased, so that an increase in roll or pitching of the vehicle body can be prevented.

Also in the above-described configuration, even if the rear wheels during traveling at a high vehicle height exceeds the pressure instantaneously and rapidly 50 kg / cm ² in through the road surface irregularities chamber 118, 118, mainly check valve
The high pressure switch 156 is not turned on by the operation of the orifice 154 and the orifice 158, and the rear wheels pass through the unevenness of the road surface while traveling at the normal vehicle height, and the chambers 118, 11
Even if the pressure inside 8 can instantaneously and suddenly exceed ² kg / cm ² , the low pressure switch 162 is
It does not become ON, and thereby unnecessary vehicle height adjustment can be prohibited.

Further, as is apparent from FIG.
When 4 is ON, the switch 176 is turned OFF and the driving of the motor 132 is prohibited, so that when the brake pedal (not shown) is depressed and both the front and rear wheels are in the braking state, the vehicle height adjustment is prohibited. become. This is because when at least one of the front and rear suspension arms extends in the front-rear direction of the vehicle body as in the above-described embodiment, if both the front and rear wheels are braked so as not to move with respect to the road surface, the suspension arm also Locked, the vehicle height cannot be adjusted.Even if the selector switch 188 is operated to the high vehicle height and the pressure in the chambers 68, 68 and the chambers 118, 118 rises, the vehicle height does not increase at all. This is because if the driver releases his / her foot from the brake pedal in this state, the vehicle height suddenly increases, which is not only uncomfortable for the occupant but also dangerous.

Next, a modification of the present invention will be described in detail with reference to FIG. 10 and FIG. In this modification, portions substantially the same as the structure shown in the above embodiment are denoted by the same reference numerals as those used above, and detailed description thereof will be omitted.

This modification differs from the above embodiment in that the second torsion bar 200 in the front suspension is connected to the rear end of the first torsion bar 16 and extends further rearward. For this reason, a spline 16b formed at the rear end of the first torsion bar 16 is fixed to the first anchor arm 28, and a sleeve 202 having a spline 202a on its inner periphery is non-rotatably fitted. The same sleeve 2
A spline 200a formed at the front end of the second torsion bar 200 is non-rotatably fitted to the spline 202a of 02. A sleeve 204 fixed to the second anchor arm 32 and having a spline 204a on its inner periphery is non-rotatably fitted to a spline 200b formed at the rear end of the second torsion bar 200.

The first anchor arm 28 is also provided with a telescopic mechanism 54 similar to that shown in FIG.
Is also controlled by a controller similar to that shown in FIGS. 8 and 9. And also in this modification,
The first anchor arm 28 and the extension mechanism 54 constitute a torsional moment applying mechanism. Although not shown, a holding member is preferably provided at the rear end portion of the first torsion bar 16 or at the front end portion of the second torsion bar 200 to rotatably hold the portion with respect to the vehicle body.

According to this modification, the same operation and effect as those of the embodiment shown in FIGS. 1 to 9 can be obtained.

FIG. 12 shows a modification of the hydraulic circuit shown in FIG. 8, in which a high pressure switch 156 and a low pressure switch 162 for detecting the pressure in one passage connecting the chambers 118, 118 and the control valve 142. Are connected via orifices 210 and 212, respectively. These orifices 210 and 212 are also for preventing the vehicle height adjustment that is not originally required from being started due to the pressure fluctuation in the chambers 118 and 118 caused by the passage of the unevenness of the road surface during traveling.

FIGS. 13 to 15 show another embodiment of the front suspension in the embodiment shown in FIGS. 1 to 12, respectively. These embodiments are the same as those in FIGS. 1 to 12. In the illustrated embodiment, the telescopic mechanism 54 is replaced with a telescopic mechanism having a configuration described below.

In FIG. 13, reference numeral 214 generally indicates a telescopic mechanism interposed between the vehicle body frame and the first anchor arm 28. The telescopic mechanism 214 includes a cylinder 218 having an upper end attached to the body frame via a bracket 216, and a cylinder 2
A piston 222 which fits in the inside 18 and defines a chamber 220, and an upper end is pivotally connected to the piston 222 via a ball joint 224 and a lower end is connected to a distal end of the first anchor arm 28 via a connecting pin 226. A connecting rod 228 is provided, and the chamber 220 is configured to supply and discharge oil by a supply and discharge device (not shown) through a port 230 provided in the cylinder 218.

The supply / discharge device communicates the chamber 220 with a reservoir (not shown) to allow the piston 222 to freely displace in the cylinder 218 (free state). In a state (locked state) displaced to the lower end.

Accordingly, when the piston 222 is in a free state, the vehicle becomes a normal vehicle height, and both the first torsion bar 16 and the second torsion bar 18 are twisted with respect to the displacement of the suspension, so that a relatively small spring constant is obtained. When the piston 222 is locked to the lower end in the cylinder 218, the vehicle height increases and only the first torsion bar 16 is twisted with respect to the displacement of the suspension. It shows the hard characteristics that it has.

FIG. 14 shows another example of the telescopic mechanism. In FIG. 14, the telescopic mechanism 230 includes a cylinder 234 having an upper end pivotally attached to the vehicle body frame via a stay 232, a piston 238 fitted in the cylinder 234 to define a chamber 236, and a piston 238 at the upper end. A piston rod 240 fixed to the lower end 238 and connected to the distal end of the first anchor arm 28 by a connecting pin 226 is provided in the chamber 236 through a port 242 provided in the cylinder 234. It is configured such that oil is supplied and discharged by the discharging device.

The supply / discharge device communicates the chamber 236 with a reservoir (not shown) so that the piston 238 can freely displace in the cylinder 234 (free state). (Locked state) that is displaced to the upper end of the disk.

Accordingly, when the piston 238 is in a free state, the vehicle becomes a normal vehicle height, and both the first torsion bar 16 and the second torsion bar 18 are twisted with respect to the displacement of the suspension, so that a relatively small spring constant is obtained. When the piston 238 is locked to the upper end of the cylinder 234, the vehicle height decreases and only the first torsion bar 16 is twisted with respect to the displacement of the suspension. It shows the hard characteristic with.

FIG. 15 shows still another example of the extension mechanism. 15, a telescopic mechanism 244 includes a cylinder 246 having a lower end connected to a distal end of the first anchor arm 28 by a connecting pin 226.
A piston 252 fitted in the cylinder 246 to define the upper chamber 248 and the lower chamber 250; and a piston rod 254 having a lower end fixed to the piston 252 and an upper end axially mounted on the body frame.
The upper chamber 248 and the lower chamber 250 each have a cylinder.
The oil supply / discharge is performed by a supply / discharge device (not shown) through ports 256 and 258 provided in the 246.

The supply / discharge device supplies oil to the upper chamber 248 while the upper chamber 248 and the lower chamber 250 both communicate with the reservoir so that the piston 252 can freely displace in the cylinder 246 (free state). A state in which the lower chamber 250 is communicated with the reservoir so that the piston 252 is displaced to the lower end of the cylinder 246 (first locked state), and further, oil is supplied to the lower chamber 250 and the upper chamber 248 is communicated with the reservoir. The state in which 252 is displaced to the upper end of the cylinder 246 (second lock state) can be taken.

Accordingly, when the piston 252 is in a free state, the vehicle becomes a normal vehicle height, and both the first torsion bar 16 and the second torsion bar 18 are twisted with respect to the displacement of the suspension, so that the spring has a relatively small spring constant. When the piston 252 is locked to the lower end of the cylinder 246 (first locked state), the vehicle height increases and only the first torsion bar 16 is twisted with respect to the displacement of the suspension. When the piston 252 is locked to the upper end of the cylinder 246 (second locked state), the vehicle height is lowered and the first torsion bar 16 is also affected by the displacement of the suspension. Only the torsion shows a hard characteristic having a relatively large spring constant.

As described above, also in the suspension device having the telescopic mechanism shown in each of FIGS. 13 to 15, the vehicle height adjustment and the spring constant control can be performed, but depending on the purpose or use of the vehicle. It is appropriately selected. For example, in the case of a vehicle that mainly performs ordinary city driving and high-speed driving, it is preferable that the vehicle can be switched between a state in which the spring constant is small at normal vehicle height and a state in which the spring constant is large at low vehicle height. If the vehicle is mainly used for traveling and running on rough roads, it is preferable that the vehicle can be switched between a normal vehicle height and a small spring constant state and a vehicle height high and a large spring constant state. If frequent running is performed not only on the road but also on rough roads, the vehicle height is normal and the spring constant is small, the vehicle height is low and the spring constant is large, and the vehicle height is high and the spring constant is large. Those that can be switched are preferred.

Note that all of the above-mentioned expansion and contraction mechanisms are based on fluid pressure. However, as long as they have the same function, for example, a mechanical or electric expansion and contraction mechanism can be adopted.

〔The invention's effect〕

As described above, according to the present invention, the vehicle height adjustment and the spring constant control can be performed simultaneously by appropriately controlling the torsional moment imparting mechanism. It is possible to provide a torsion bar type suspension device that can cope with required rough road traveling or high speed traveling requiring a low center of gravity.

[Brief description of the drawings]

1 is a perspective view showing a front suspension according to one embodiment of the present invention, FIG. 2 is an enlarged plan view of a portion II in FIG. 2, FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 shows the third
FIG. 5 is a sectional view taken along the line IV-IV of FIG.
FIG. 6 is an enlarged sectional view showing the rear suspension according to the embodiment, FIG. 7 is an enlarged sectional view showing the coil spring 116 of FIG. 6, and FIG. FIG. 9 is an explanatory diagram showing a hydraulic supply / discharge device according to an embodiment, FIG. 9 is an explanatory diagram showing a control circuit according to the one embodiment, FIG. 10 is a perspective view showing a modification of the present invention, and FIG.
FIG. 10 is a sectional view taken along line XI-XI of FIG. 10, FIG. 12 is an explanatory view showing a modification of the hydraulic supply / discharge device shown in FIG. 8, and FIG. 13 is another expansion / contraction mechanism that can be used for the front suspension. FIG. 14 is a cross-sectional view showing another example of the telescopic mechanism, and FIG. 15 is a cross-sectional view showing another example of the telescopic mechanism. 6 Lower arm, 16 First torsion bar, 118
... second torsion bar, 28 ... first anchor arm, 32 ...
... Second anchor arm, 54 ... Expansion mechanism

Claims (1)

(57) [Claims] A torsion bar having one end connected to the suspension arm and the other end non-rotatably connected to the vehicle body; A torsion bar type suspension device interposed between a vehicle body and a torsion bar applying mechanism capable of applying a torsional moment to the torsion bar.