JPH10138729A - Car height adjusting device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the car height to be lowered normally, but raise the height quickly and by a simple operation when necessary, and efficiently adjust the height without damaging the function of leaf springs. SOLUTION: One end of an outer cylinder 17 and one end of an inner cylinder 19 are respectively pivoted on a chassis frame and an axle, the other end of the inner cylinder 19 is inserted into the outer cylinder 17, and the first liquid 26 is sealed in the inside of the inner cylinder. The first and second pistons 21, 22 connected by a piston rod 23 having an insertion hole 23a are respectively inserted into the outer cylinder 17 and the inner cylinder 19, and a liquid supply and discharge means 24 supplies and discharges the second liquid 29 to and from the first liquid chamber 31 of the outer cylinder 17. An orifice 23b connecting the second and third liquid chambers is formed in the piston rod 23, and a valve body 34 is inserted into a recesses part 21a of the first piston 21. A valve body-rod 36 made integrally with the valve body 34 is inserted into the insertion hole so that the orifice can be opened, and the valve body is energized by an elastic body 41 in the direction in which it is separated from the bottom of the recessed part. By switching a car height switching switch 51 at the driver's seat, the liquid supply and discharge means supplies and discharges the second liquid to and from the first liquid chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle, and more particularly to a vehicle which is usually driven at a low height to improve the getting on and off performance, and which is raised when traveling on a bad road such as a railroad crossing or a steep slope. The present invention relates to a vehicle height adjusting device suitable for a fixed route bus.

[0002]

2. Description of the Related Art Conventionally, one end of a leaf spring attached to an axle of a front wheel of a four-wheel drive vehicle is attached to a chassis frame via a front spring bracket, and the other end of the leaf spring is connected to a crank arm via a shackle. Pivotally attached to one arm, the approximate center of this crank arm is pivotally attached to the chassis frame via a bracket,
Further, there is disclosed a leaf spring type suspension with a vehicle height adjusting function in which the other arm of a crank arm is pivotally attached to a piston rod of a hydraulic cylinder fixed to a chassis frame (Japanese Patent Application Laid-Open No. Hei 7-251622). In this leaf spring type suspension, a hydraulic pump is connected to the hydraulic cylinder via a hydraulic switching valve, and the hydraulic switching valve is configured to be switched by a vehicle height switching switch provided in a driver's seat.

In this leaf spring type suspension, when a vehicle height changeover switch is turned on when traveling on a rough road, a hydraulic pressure changeover valve is switched to supply hydraulic oil from a hydraulic pump to a hydraulic cylinder. The supply of pressure oil to the hydraulic cylinder causes the piston rod to protrude, and one arm of the crank arm pushes down the other end of the leaf spring via the shackle, increasing the vertical distance between the axle and the chassis frame, thereby increasing the chassis frame. Above the ground.
As a result, the running performance on rough roads is improved.

[0004]

However, in the above-mentioned conventional leaf spring type suspension with a vehicle height adjustment function,
Since the vehicle height is adjusted by moving the other end of the leaf spring up and down, there is a problem that the vehicle height can be adjusted only about half the vertical movement distance of the other end of the leaf spring.
If one arm of the crank arm is lengthened to eliminate this point, the leaf spring may tilt downward at a relatively large angle when the vehicle height is increased, and the original function of the leaf spring may be impaired. there were. Further, in the above-mentioned conventional leaf spring suspension with a vehicle height adjustment function, a hydraulic pump must be newly mounted, and there is a problem that the number of parts and the number of assembling steps are increased. An object of the present invention is to reduce the vehicle height during normal driving, to quickly raise the vehicle height by simple operation when necessary, and to increase the leaf number by increasing the number of parts and the number of assembly steps. An object of the present invention is to provide a vehicle height adjusting device capable of efficiently adjusting the vehicle height without impairing the function of a spring.

[0005]

The invention according to claim 1 is
As shown in FIGS. 1 and 3, a leaf spring 13 interposed between the axle 11 and the chassis frame 12 and suspending the chassis frame 12, the axle 11 and the chassis frame 12
And a shock absorber 14 interposed between them to suppress the vibration of the leaf spring 12.
The characteristic configuration is that the shock absorber 14 is provided with the outer cylinder 1 having one end pivotally attached to the chassis frame 12 or the axle 11.
7, one end is pivotally connected to the axle 11 or the chassis frame 12 and the other end is slidably inserted into the outer cylinder 17 and has the first inside.
The inner cylinder 19 in which the liquid 26 is sealed, the first piston 21 slidably inserted into the outer cylinder 17, the second piston 22 slidably inserted into the inner cylinder 19, the first piston 21 and The second piston 22 is connected and the insertion hole 23a is formed along the axis.
And a liquid supply / discharge unit 24 capable of supplying / discharging the second liquid 29 to / from a first liquid chamber 31 formed between the inner end surface of the outer cylinder 17 and the top surface of the first piston 21. When,
The second pistons 22 are respectively formed in the inner cylinder 19 and partitioned on the one end side and the other end side of the inner cylinder 19 by the second piston 22.
And an orifice 23b formed on a side surface of the piston rod 23 near the second piston 22 and communicating with the second and third liquid chambers 32 and 33; and a top surface of the first piston 21 The valve body 34 is slidably inserted into the recess 21a formed in the valve body 34. The valve body 34 is formed integrally with the valve body 34 and slides in the insertion hole 23a together with sliding in the recess 21a. A valve body rod 36 capable of opening and closing the orifice 23b and a valve body 34 interposed between the valve body 34 and the bottom surface of the recess 21a to urge the valve body 34 in a direction away from the bottom surface of the recess 21a and supplied to the first liquid chamber 31. An elastic body 41 having an elastic force smaller than a pressing force of the valve body 34 by the pressure of the second liquid 29, and a vehicle height changeover switch 51 which is switched by a driver to raise and lower the vehicle height is provided in a driver's seat. , Turn off the vehicle height switch 51 There is to configured to supply and discharge the second liquid 29 into the first liquid chamber 31 via the liquid supply and discharge means 24 by obtaining.

In the vehicle height adjusting apparatus according to the first aspect, the vehicle is normally in a state where the first piston 21 of the shock absorber 14 is in contact with the inner end surface of the outer cylinder 17, that is, in a state where the vehicle height is reduced. Since the vehicle travels on a flat, paved road, it is easy to get on and off the vehicle. Also, at this time, since the orifice 23b is open, the passage of the first liquid 26 in the inner cylinder 19 through the small orifice 23b becomes a resistance of the second piston 22 to the vertical movement relative to the inner cylinder 19, The vibration of the leaf spring 13 can be suppressed. When the vehicle is traveling on a rough road, the liquid supply / discharge unit 24 is switched to the second position by switching the vehicle height changeover switch 51.
The liquid 29 is supplied to the first liquid chamber 31. The second liquid 29 supplied to the first liquid chamber 31 pushes down the valve body rod 36 via the valve body 34 against the elastic force of the elastic body 41 to close the orifice 23b, and further the first piston 29 Since the vehicle 21 is lowered with respect to the outer cylinder 17, the vehicle height is increased, and the vehicle can travel smoothly on a rough road.

The invention according to claim 2 is the invention according to claim 1, wherein the second liquid 29 supplied and discharged to the first liquid chamber 31 is oil, as shown in FIG. Supply / discharge means 24
Has a hydraulic pump 37 for supplying and discharging the second liquid 29 to and from the power steering gear, and a switching valve 39 provided in a conduit 38 connecting the hydraulic pump 37 and the first liquid chamber 31. , The switching valve 39 is switched to supply and discharge the second liquid 29 to and from the first liquid chamber 31. In the vehicle height adjusting device according to the second aspect, since the existing hydraulic pump 37 for power steering can be used as the liquid supply / discharge means 24, the number of parts and the number of assembling steps can be slightly increased.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the first piston 81 comes into contact with the inner end surface of the outer cylinder 17 as shown in FIG. First piston fixing means 71 for fixing piston 81 to outer cylinder 17
And first piston position sensors 91a and 91b for detecting the position of the first piston 81;
a, 91b and a controller 78 for controlling the first piston fixing means 71 based on the respective detection outputs of the vehicle height changeover switch 51. In the vehicle height adjusting device according to the third aspect, the first piston position sensor 9 is provided.
When the controller 1a detects that the first piston 81 has contacted the inner end surface of the outer cylinder 17, the controller 78
The first piston fixing means 71 is actuated based on the detected output a to fix the first piston 81 to the outer cylinder 17.

The invention according to claim 4 is the invention according to claims 1 to 3
According to the invention, as further shown in FIG. 1 or FIG.
The accumulator 28 is connected to the first liquid chamber 31. In the vehicle height adjusting device according to the fourth aspect, even when the vehicle height is high, the accumulator 28 is not required.
The first piston 21 or 81 relatively moves with respect to the outer cylinder 17 due to the repeated compression and expansion of the gas 30 inside.

[0010]

Next, a first embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 to 3, a leaf spring 13 for suspending the chassis frame 12 is interposed between the axle 11 of the front wheel of the route bus and the side member 12 a of the chassis frame 12, and the axle 11 and the side member 12 a Between them, a shock absorber 14 for suppressing vibration of the leaf spring 13 is interposed. The shock absorber 14 has an outer cylinder 17 whose upper end is pivotally connected to the side member 12 a via a shaft 16, and a lower end which is pivotally connected to the axle 11 via a shaft 18, and an oil 26 as a first liquid is sealed inside. The inner cylinder 19, the first piston 21 slidably inserted into the outer cylinder 17, the second piston 22 slidably inserted into the inner cylinder 19, and the first and second pistons 21, 22 are connected. Piston rod 23 and outer cylinder 1
The oil 29 as the second liquid is stored in the first liquid chamber 31 formed in the inside 7.
And a liquid supply / discharge unit 24 capable of supplying / discharging the liquid.

The outer cylinder 17 is formed in a cylindrical shape in which the upper end is closed by an upper wall 17a and the lower end is opened, and the inner cylinder 19 is formed in a cylindrical shape in which both ends are closed by an upper wall 19a and a lower wall 19b ( 1 and 2). The upper end of the inner cylinder 19 is the outer cylinder 1
7 is slidably inserted from the lower end thereof, and a small amount of gas 27 such as nitrogen gas is sealed in the inner cylinder 19 in addition to the oil 26. The gas 27 inside the inner cylinder 19 is
Enclosed so that it can move up and down. That is, when the inner cylinder 19 rises with respect to the outer cylinder 17, the piston rod 23 is relatively inserted into the inner cylinder 19.
9 is secured by compressing the gas 27, and when the inner cylinder 19 descends with respect to the outer cylinder 17, the piston rod 23 moves relative to the inner cylinder. 19, but this inner cylinder 1
The gas 27 is sealed in the inner cylinder 19 so that the oil 27 corresponding to the volume of the piston rod 23 detached from the pipe 9 flows from the escape field by the expansion of the gas 27. An insertion hole 23 a is formed in the piston rod 23 along the axis of the rod 23. The first liquid chamber 31 is formed between the lower surface of the upper wall 17 a of the outer cylinder 17 and the top surface of the first piston 21.
And an accumulator 28 in which the same oil 29 as the oil 29 in the first liquid chamber 31 is sealed in the lower part. The upper wall 17a of the outer cylinder 17 has oil 2 in the first liquid chamber 31.
A supply / discharge port 17b for supplying / discharging 9 is formed.

The interior of the inner cylinder 19 is partitioned by a second piston 22 into an upper second liquid chamber 32 and a lower third liquid chamber 33, and the side surface of the piston rod 23 is located adjacent to the second piston 22. Orifice 2 communicating the second and third liquid chambers 32 and 33
3b is formed. A concave portion 21a is formed on the top surface of the first piston 21, and a valve element 34 is slidably inserted into the concave portion 21a. The upper end of a valve rod 36 is connected to the center of the lower surface of the valve body 34.
It is slidably inserted into 3a. The valve body rod 36 is configured to open and close the orifice 23b by sliding in the insertion hole 23a together with sliding in the recess 21a of the valve body 34. A first compression coil spring 41, which is an elastic body of the present invention, is interposed between the valve body 34 and the bottom surface of the recess 21a. The spring 41 urges the valve body 34 in a direction away from the bottom surface of the recess 21 a, and supplies the oil 29 supplied to the first liquid chamber 31.
Has a smaller elastic force than the pressing force of the valve element 34 due to the pressure of Reference numeral 42 in FIGS. 1 and 2 denotes a second compression coil spring interposed between the first piston 21 and a stepped portion 17c formed inside the outer cylinder 17. The spring 42 is a first piston. 21 is urged upward. That is, when the pressure of the oil 29 in the first liquid chamber 31 decreases, the second compression coil spring 42 pushes the first piston 21 upward, so that the first piston 21 When the first compression coil spring 41 comes into contact with the valve body 34 and pushes up the valve body 34, the orifice 23b is opened and the second and third liquid chambers 32 and 33 communicate with each other. Thereby, the shock absorber 14 plays a role of damping the vibration.

The liquid supply / discharge means 24 includes a hydraulic pump 37 for supplying and discharging oil 29 to and from a power steering gear (not shown),
Pipe line 3 connecting the hydraulic pump 37 and the first liquid chamber 31
And a switching valve 39 provided at the position 8. The power steering gear is housed in a gear box 43 into which a lower end of a steering shaft 46 having a steering wheel 44 fixed to an upper end is inserted. The discharge port 37 of the hydraulic pump 37 is connected to a feed pipe 48.
Is connected to the gear box 43 through the hydraulic pump 37.
Is connected to the gear box 43 via a return pipe 49. Although not shown, an oil tank for storing the oil 29 is provided in the return pipe 49.

The switching valve 39 is a three-port three-position switching electromagnetic valve, and has a case 39c in which a single first slide chamber 39a is formed at the center and a pair of second slide chambers 39b, 39b are formed at both ends. A valve body 39d slidably inserted into the first slide chamber 39a, a pair of valve rods 39e, 39e each having one end connected to both ends of the valve body 39d, and these rods 39e, 39e.
A pair of third pistons 39f, 39f respectively connected to the other ends of the pair of second slide chambers 39b, 39b and slidably inserted into the pair of second slide chambers 39b; Second slide chamber 39
b, 39b and a pair of coils 3 respectively provided
9 g and 39 g.

A pair of third compression coil springs 39 having the same spring characteristics are provided in the pair of second slide chambers 39b, 39b.
h, 39h, and these springs 39h, 39h are connected to the third pistons 39f, 39f and the valve rod 39.
The valve body 39d is urged to be located at the center of the first slide chamber 39a via the valves e and 39e. Case 3
9c, a first port 39i that communicates near the right end of the first slide chamber 39a, a second port 39j that communicates near the left end of the first slide chamber 39a, and a third port that communicates with the center of the first slide chamber 39a. 39k are formed. A conduit 38 connecting the hydraulic pump 37 and the first liquid chamber 31 is connected to a first port 39i connecting the feed pipe 48 to the first port 39i.
Pipe 38a, second port 39j and return pipe 49
And a third pipe 38c connecting the third port 39k and the supply / discharge port 17b of the outer cylinder 17.

The pair of coils 39g, 39g are electrically connected to a battery 52 via a vehicle height changeover switch 51 provided in a driver's seat (not shown). The switch 51 is a normally-open switch for three-position switching of manual operation and automatic return.
g, and the switching contact c is connected to the right coil 39
g, and the common contact a is connected to the battery 52. When the switch 51 is connected to the switching contact b, a current flows through the left coil 39g, and a leftward suction force acts on the left valve rod 39e, so that the valve body 39
d moves to the left end of the first slide chamber 39a to communicate the first port 39i and the third port 39k. When the switch 51 is connected to the switching contact c, a current flows through the right coil 39g and the right valve rod 3
9e receives a rightward suction force, and the valve body 39d is moved to the first position.
It is configured to move to the right end of the slide chamber 39a to communicate the second port 39j and the third port 39k.

In this embodiment, a route bus is described as a vehicle, but this is merely an example, and a sightseeing bus or another vehicle may be used. The axle may be a rear wheel axle instead of a front wheel axle. Further, in this embodiment, one end of the outer cylinder is pivotally attached to the chassis frame, and one end of the inner cylinder is pivotally attached to the axle. However, the present invention is not limited to this. One end may be pivotally connected to the chassis frame. Further, in this embodiment, oil is supplied or sealed in the first to third liquid chambers, but a liquid other than oil may be used. Furthermore, in this embodiment, a small amount of gas such as nitrogen gas is filled in the inner cylinder in addition to oil so that the piston rod can be inserted or removed from the inner cylinder. Fill,
An accumulator filled with oil and gas may be connected to the inner cylinder.

The operation of the thus-configured vehicle height adjusting device will be described. Normally, a route bus (not shown) is on a flat paved road with the first piston 21 of the shock absorber 14 in contact with the inner end surface of the outer cylinder 17 (FIG. 1), that is, with the vehicle height lowered. Therefore, when a passenger (not shown) stops at a stop and gets on and off, the height from the road surface to a step (not shown) is relatively low, and the passenger gets on and off easily. Further, at this time, the valve body 34 is located at the highest position together with the valve body rod 36 due to the elastic force of the first compression coil spring 41. As a result, since the orifice 23b is open, the oil 26 in the inner cylinder 19 is discharged from the small orifice 23b.
Since the passage of b causes resistance of the second piston 22 to move up and down relative to the inner cylinder 19, vibration of the leaf spring 13 can be suppressed.

When the route bus approaches a bad road such as a railroad crossing or a steep hill, a driver (not shown) connects the vehicle height changeover switch 51 to the changeover contact b (FIG. 2). This switch 5
By the operation 1, the current flows through the coil 39g on the left side of the switching valve 39, and the valve body 39d is moved to the first slide chamber 39a.
(FIG. 2), and the first port 39i communicates with the third port 39k. Discharge port 37a of hydraulic pump 37
The oil 29 discharged from the feed pipe 48, the first pipe 38a, the first port 39i, the first slide chamber 39a, the third port 39k, the third pipe 38c, and the supply / discharge port 17b
Through the first liquid chamber 31. The oil 29 supplied to the first liquid chamber 31 first causes the valve body 34 to move the first compression coil spring 4
By pushing down against the elastic force of No. 1, the valve body rod 36 is pushed down to close the orifice 23b (FIG. 2).
When the oil 29 is further supplied to the first liquid chamber 31, the first piston 21 descends with respect to the outer cylinder 17, and the distance between the upper shaft 16 and the lower shaft 18 of the shock absorber 14 increases (see FIG. 4). 2). As a result, the vehicle height increases, so that the bus can travel smoothly on rough roads such as railroad crossings and steep hills.

Since the vehicle height changeover switch 51 is automatically separated from the switching contact b when the hand is released, the first liquid chamber 31 is provided only when the driver connects the switch 51 to the switching contact b.
The oil 29 is supplied to the vehicle and the vehicle height can be adjusted to a desired value. To lower the vehicle height, the switch 51 may be connected to the switching contact c. At this time, the coil 39 on the right side of the switching valve 39
g, and the valve body 39d is moved to the first slide chamber 3
9a, the oil 29 in the first liquid chamber 31 is supplied to the supply / discharge port 17b, the third conduit 38c, the third port 39k,
First slide chamber 39a, second port 39j, second conduit 3
8b, return to the return pipe 49, the first liquid chamber 31
The internal pressure decreases, and increases due to the elastic force of the second compression coil spring 42, so that the first piston 21 contacts the inner end surface of the outer cylinder 17. Further, since the pressure in the first liquid chamber 31 is reduced, the valve body 34 rises together with the valve body rod 36 by the elastic force of the first compression coil spring 41, and the orifice 23b
Is released. When the vehicle height is further increased, since the valve body rod 36 closes the orifice 23b, the second piston 22 does not move relative to the inner cylinder 19,
Instead, the gas 27 in the accumulator 28 repeatedly compresses and expands, so that the first piston 21 moves relative to the outer cylinder 17.
4 performs some buffering function.

FIGS. 4 and 5 show a second embodiment of the present invention. 4 and 5, the same reference numerals as those in FIG. 1 indicate the same parts. In this embodiment, the shock absorber 7
4, first piston fixing means 71 for fixing the first piston 81 to the outer cylinder 17 in a state where the first piston 81 is in contact with the inner end surface of the outer cylinder 17 is attached to the outer peripheral surface of the outer cylinder 17,
A pair of first piston position sensors 91 a and 91 b for detecting the position of the piston 81 are attached to the outer peripheral surface of the outer cylinder 17. The first piston fixing means 71 is provided in a case 71a attached to the outer peripheral surface of the outer cylinder 17, a plunger 71b which faces the inside of the outer cylinder 17 from the case 71a and is provided so as to be able to protrude and retract from the case 71a, and is built in the case 71a. A fourth compression coil spring (not shown) for urging the plunger 71b in a direction to protrude from the case 71a, and a plunger 71b built in the case 71a and for energizing the plunger 71b when energized against the elastic force of the fourth compression coil spring. And a coil (not shown) to be drawn in. A ring-shaped concave groove 81b into which the plunger 71b can be inserted when the first piston 81 contacts the inner end surface of the outer cylinder 17 is formed on the outer peripheral surface of the first piston 81.

A pair of first piston position sensors 91a, 9
1b is attached to the outer peripheral surface near the upper end of the outer cylinder 17, and the other sensor 91b is attached to the outer cylinder 17
Is mounted a predetermined distance below the one sensor 91a on the outer peripheral surface of the sensor. These sensors 91a, 91
Reference numeral b denotes a magnetic proximity switch using a reed switch, a Hall element / a magnetoresistive element, a magnetic coil, or the like as a detecting element. Also, the first piston 81 has
When the piston 81 comes into contact with the inner end surface of the outer cylinder 17, a ring-shaped magnet 72 is embedded facing the one sensor 91 a, and the first piston 81 descends most with respect to the outer cylinder 17 in this magnet 72. Sometimes the other sensor 91b
It is constituted so that it may face. The first piston 81 and the outer cylinder 17 are formed of a non-magnetic metal material such as austenitic stainless steel so as not to be magnetized by the magnet 72. In a driver's seat (not shown), a vehicle height up ramp 76 and a vehicle height down ramp 77 are provided.

A pair of first piston position sensors 91a, 9
1b and the changeover contacts b and c of the vehicle height changeover switch 51 are connected to the control input of the controller 78,
Is connected to the coil of the first piston fixing means 71, the vehicle height up ramp 76, the vehicle height down ramp 77, and a pair of coils 39g, 39g of the switching valve 39, respectively. Except for the above, the configuration is the same as that of the first embodiment. In this embodiment, a magnetic proximity switch is used as the first piston position sensor, but a high-frequency proximity switch, a capacitance proximity switch, or another position detection sensor may be used.

The operation of the thus-configured vehicle height adjusting device will be described. When a route bus (not shown) is running at a reduced vehicle height, the first piston 81
7 (FIG. 4), since the magnet 72 faces one of the first piston position sensors 91a (FIG. 4), the controller 78 fixes the first piston based on the detection output of the sensor 91a. Deactivate means 71.
As a result, the plunger 71b projects from the case 71a by the elastic force of the fourth compression coil spring, and the first piston 81b
The first piston 81 can be reliably fixed in a state in which the first piston 81 is in contact with the inner end surface of the outer cylinder 17. Further, the controller 78 turns on the vehicle height down lamp 77 based on the detection output of the sensor 91a.

When the route bus approaches a bad road such as a railroad crossing or a steep hill, a driver (not shown) connects the vehicle height changeover switch 51 to the changeover contact b (FIG. 5) and immediately releases his hand. .
The controller 78 detects that the switch 51 is once connected to the switching contact b, and first supplies a current to a coil (not shown) of the first piston fixing means 71 to cause the plunger 7 to move.
1b is pulled into the case 71a. As a result, the plunger 71b separates from the concave groove 81b of the first piston 81, and the first piston 81 becomes slidable with respect to the outer cylinder 17. Next, the controller 78 operates the coil 3 on the left side of the switching valve 39.
Apply current to 9 g. As a result, the valve body 39d
By moving to the left end of the slide chamber 39a (FIG. 5), the first port 39i and the third port 39k communicate with each other, and the hydraulic pump 37
The oil 29 discharged from the discharge port 37a of the orifice 2 is supplied to the first liquid chamber 31, and the oil 29 pushes down the valve body 34 and pushes down the orifice 2.
After closing 3b, the first piston 81 is lowered with respect to the outer cylinder 17.

At this time, since the magnet 72 is separated from the first piston position sensor 91a, the controller 7
8 turns off the vehicle height down lamp 77 based on this detection output. When the first piston 81 is farthest from the inner end surface of the outer cylinder 17, the magnet 72 faces the other first piston position sensor 91b (FIG. 5).
Turns on the vehicle height up lamp 76 based on the detection output of the sensor 91b and stops the supply of current to the coil 39g on the left side of the switching valve 39 to stop the supply of the oil 29 to the first liquid chamber 31. To lower the vehicle height, the vehicle height changeover switch 51 may be connected to the changeover contact c. In this manner, the driver momentarily switches the changeover switch 51 to the changeover contact b or c.
, The vehicle height can be raised or lowered to a predetermined height. Further, the driver can confirm whether the bus height is high or low just by visually checking the lighting of the vehicle height up lamp 76 or the vehicle height down lamp 77. Operations other than those described above are substantially the same as those in the first embodiment, and a description thereof will not be repeated.

[0027]

As described above, according to the present invention, one end of the outer cylinder is pivotally connected to the chassis frame or the axle, one end of the inner cylinder is pivotally connected to the axle or the chassis frame, and the other end of the inner cylinder. Is inserted into the outer cylinder, the first liquid is sealed therein, and the first and second pistons connected by the piston rod having the insertion holes are inserted into the outer cylinder and the inner cylinder, and the second and second pistons in the inner cylinder are inserted. An orifice communicating with the three liquid chambers is formed in the piston rod,
A valve body rod integrated with the valve body inserted into the recess on the top surface of the piston is inserted into the insertion hole so that the orifice can be opened and closed, and the elastic body urges the valve body in the direction away from the bottom surface of the recess. By switching the vehicle height changeover switch, the liquid supply / discharge means supplies / discharges the second liquid to / from the first liquid chamber of the outer cylinder. Therefore, when traveling on a flat paved road, the vehicle height is reduced. Thus, the first liquid in the inner cylinder can be passed through the orifice that has been opened to allow the shock absorber to have the function of damping the leaf spring, which is the original function of the absorber.

When the vehicle is traveling on a rough road, the second liquid is supplied to the first liquid chamber by the liquid supply / discharge means by switching the vehicle height changeover switch, and the supplied second liquid closes the valve body. The orifice is closed by the rod for the valve body by being pressed down against the elastic force of the elastic body, and the first piston is further lowered with respect to the outer cylinder. As a result, the vehicle height can be quickly increased by a simple operation, and the vehicle can travel smoothly on a rough road. The second liquid supplied to and discharged from the first liquid chamber is oil,
The liquid supply / discharge means has a hydraulic pump for supplying / discharging the second liquid to / from the power steering gear and a switching valve provided in a pipeline connecting the hydraulic pump and the first liquid chamber, and switches a vehicle height switch. To switch the switching valve
If the liquid chamber is configured to supply and discharge the second liquid, the existing hydraulic pump for power steering can be used as the liquid supply and discharge means, so that the number of parts and the number of assembling steps can be slightly increased.

Further, since the vehicle height is adjusted by moving the other end of the leaf spring up and down, the conventional leaf with a vehicle height adjustment function can adjust the vehicle height only by a distance approximately half the vertical movement distance of the other end of the leaf spring. Compared with the spring type suspension, in the present invention, the vehicle height is increased by the distance of the first piston from the inner end surface of the outer cylinder, so that the vehicle height can be adjusted efficiently. Also, by improving the conventional leaf spring suspension with height adjustment function and increasing the length of one of the crank arms, when the vehicle height is increased, the leaf spring tilts downward at a relatively large angle and falls backward. There was a risk of impairing the original function of
In the present invention, the function of the leaf spring is hardly impaired.

Further, the vehicle height adjusting device of the present invention detects first piston fixing means for fixing the first piston to the outer cylinder when the first piston contacts the inner end face of the outer cylinder, and detects the position of the first piston. If there is provided a first piston position sensor and a controller for controlling the first piston fixing means based on each detection output of the first piston sensor and the vehicle height changeover switch, the first piston position sensor is configured such that the first piston is an outer cylinder. When the controller detects that it has come into contact with the inner end face, the controller operates the first piston fixing means based on the detection output of this sensor to fix the first piston to the outer cylinder. As a result, the state where the vehicle height is reduced can be reliably maintained. Furthermore, if an accumulator is connected to the first liquid chamber, even if the vehicle height is high,
As the gas in the accumulator repeats compression and expansion, the first piston moves relative to the outer cylinder. As a result, even when the orifice is closed, the shock absorber functions as a shock absorber.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram illustrating a state in which a vehicle height is reduced by a vehicle height adjustment device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram corresponding to FIG. 1, showing a state where the vehicle height is increased by the vehicle height adjustment device.

FIG. 3 is a sectional view of a main part of a vehicle including the vehicle height adjusting device.

FIG. 4 is a sectional view showing a second embodiment of the present invention and corresponding to FIG. 1;

FIG. 5 is a cross-sectional configuration diagram corresponding to FIG. 4, showing a state where the vehicle height is increased by the vehicle height adjustment device.

[Explanation of symbols]

 Reference Signs List 11 axle 12 chassis frame 13 leaf spring 14, 74 shock absorber 17 outer cylinder 19 inner cylinder 21, 81 first piston 21a recess 22 second piston 23 piston rod 23a insertion hole 23b orifice 24 liquid supply / discharge means 26 oil (first liquid) ) 28 Accumulator 29 Oil (second liquid) 31 First liquid chamber 32 Second liquid chamber 33 Third liquid chamber 34 Valve element 36 Rod rod 37 Hydraulic pump 38 Pipe line 39 Switching valve 41 First compression coil spring (elasticity) Body) 51 Vehicle height changeover switch 71 First piston fixing means 78 Controller 91a, 91b First piston position sensor

Claims (4)

[Claims] 1. A leaf spring (13) interposed between an axle (11) and a chassis frame (12) for suspending the chassis frame (12), the axle (11) and the chassis frame (12)
A shock absorber (14) interposed between the shock absorber (14) and the shock absorber (14) for suppressing vibration of the leaf spring (13), wherein one end of the shock absorber (14) is attached to the chassis frame (12) or the axle (11). A pivotally mounted outer cylinder (17), one end of which is pivotally connected to the axle (11) or chassis frame (12) and the other end is slidably inserted into the outer cylinder (17) and has a first liquid ( 26), and a first piston (21, slidably inserted into the outer cylinder (17).
81) and a second piston (22) slidably inserted into the inner cylinder (19).
A piston rod (23) connecting the first piston (21, 81) and the second piston (22) and having an insertion hole (23a) formed along an axis; and the outer cylinder (17). A liquid supply / discharge means (24) capable of supplying / discharging the second liquid (29) to / from a first liquid chamber (31) formed between an inner end surface and a top surface of the first piston (21, 81); The second piston (2) formed in the inner cylinder (19), respectively.
2) second and third liquid chambers (32, 33) partitioned on one end side and the other end side of the inner cylinder (19), respectively, and the second piston (22) on the side surface of the piston rod (23). )
The second and third liquid chambers (32, 33) formed in close proximity to
An orifice (23b) communicating with the first piston (21, 81); and a recess (21a) formed on the top surface of the first piston (21, 81).
A valve element (34) slidably inserted into the valve element (34), and the insertion hole (23a) formed integrally with the valve element (34) while sliding in the recess (21a) of the valve element (34). ), A valve body rod (36) that can open and close the orifice (23b) by sliding inside, and the valve body (34) is interposed between the valve body (34) and the bottom surface of the recess (21a). 34) is biased in a direction away from the bottom surface of the concave portion (21a), and the elasticity is smaller than the pressing force of the valve body (34) due to the pressure of the second liquid (29) supplied to the first liquid chamber (31). An elastic body (41) having a force, a vehicle height changeover switch (51) that is switched by a driver to raise and lower the vehicle height is provided in a driver's seat, and the vehicle height changeover switch (51) is switched to switch the vehicle height changeover switch (51). The second liquid (2) is supplied to the first liquid chamber (31) through the liquid supply / discharge means (24).
9) A vehicle height adjusting device configured to supply and discharge 9). 2. A second liquid (29) supplied to and discharged from a first liquid chamber (31).
Is oil, and the liquid supply / discharge means (24) is connected to the power steering gear by the second
The hydraulic pump (37) for supplying and discharging the liquid (29) and this hydraulic pump (3
7) and a switching valve (39) provided in a pipe line (38) connecting the first liquid chamber (31), and the switching valve (39) is switched by switching a vehicle height switch (51). And the second liquid (2) is stored in the first liquid chamber (31).
The vehicle height adjusting device according to claim 1, wherein the vehicle height adjusting device is configured to supply and discharge the fuel. 3. A first piston fixing means (71) for fixing the first piston (81) to the outer cylinder (17) when the first piston (81) contacts the inner end surface of the outer cylinder (17). ), A first piston position sensor (91a, 91b) for detecting a position of the first piston (81), and a detection output of the first piston sensor (91a, 91b) and a vehicle height changeover switch (51). 2. A controller (78) for controlling said first piston fixing means (71) based on said controller.
Or the vehicle height adjusting device according to 2. 4. The vehicle height adjusting device according to claim 1, wherein an accumulator (28) is connected to the first liquid chamber (31).