JPH0739272B2 - Cab tail suspension device - Google Patents

Description

The present invention relates to a cab tilt / suspension device which absorbs vibration of a cab by liquid flow and elasticity of gas and which is provided with an actuator having a cab tilt function. Regarding

[Conventional technology]

Conventionally, in an actuator of a suspension used in a suspension system of an automobile, etc., as shown in FIG. 8, a cylinder 141 containing oil is slidably inserted into a cylinder 141 containing oil so that the cylinder 142 A piston 144 having an orifice 143 at the tip is fixed, and a partition piston is further provided inside the cylinder 142.
145 is fitted so as to be slidable and sealed. A gap 146 is formed between the cylinder 141 and the cylinder 142, and the gas chamber 14 formed by the partition piston 145 and the cylinder 142 is formed.
A gas such as nitrogen gas is enclosed in 8. Cylinder 141
Oil is contained in an oil chamber 150 formed by a cylinder 142 and a cylinder 142, and oil is allowed to flow into and out of an oil chamber 149 formed by the piston 144, the partition piston 145 and the cylinder 142 through an orifice 143. ing.

The oil chamber 150 communicates with a hydraulic pressure source 154 or a reserve tank 158 through a pipe 151. Oil is supplied from the hydraulic pressure source 154 to the oil chamber 150 via the safety valve 155, the electromagnetic switching valve 152, and the check valve 156. The oil from the oil chamber 150 is discharged to the reserve tank 158 via the electromagnetic switching valve 153. In the figure, 147 is a sealing member, and 157 is a conduit communicating with another actuator (not shown). In the actuator 140, when the actuator 140 is displaced, the tubular body 142 is vertically displaced in the cylinder 141, so that the oil in the cylinder 141 passes through the orifice 143 to flow in and out of the oil chamber 149. As a result, the partition piston 145 moves up and down, and the gas chamber 1
The volume inside 48 changes and the pressure inside the gas chamber 148 changes.
Since the cross-sectional area inside the gas chamber 148 is constant, the load received by the actuator 140 fluctuates and acts as a spring. The damping force is generated by the piston 142 moving in the cylinder 141 due to the expansion and contraction of the cylinder 142 with respect to the cylinder 141, and the oil flowing through the orifice 143.

As the above-mentioned actuator, for example, JP-A-59-145612 is used.
What is disclosed in the publication is outlined with reference to FIG. A vehicle height adjusting device 160 using the actuator includes a cylinder 161, which contains oil, a rod 163, which is slidably inserted into the cylinder 161, and has a piston 162 having an orifice 164, and oil enters and leaves the cylinder 161. Comprised of possible hydraulic units 165. Cylinder 161 and rod 16
Insert the seal member 166 in the sliding part between the
161 includes a gap 167 of the sliding portion on the leak side of the seal member 166.
Is provided with a leak oil outlet 168 communicating with. The leak oil outlet 168 is connected to the hydraulic unit 16 via an oil feed pipe 169.
5 is connected to reserve tank 170.

In recent years, some actuators of this type are used in combination with an electric oil pump, a sensor and the like to perform leveling of a vehicle to improve ride comfort performance. In addition, as a cab suspension, a cab suspension in which a cab tilt mechanism is used in combination is disclosed. This will be outlined with reference to FIG.

In the cab tilt suspension device shown in FIG. 10, a cab 180 is supported by a vehicle body frame 171 via a shock absorber 173 of the cab suspension and a coil spring 177. A tilt center 176 is set at the front end of the cab 180, one end of a shock absorber 173 is pivotally attached to the tilt center 176, and the other end of the shock absorber 173 is pivotally attached to the vehicle body frame 171.

A link arm bracket 174 is fixed to the body frame 171, and both ends of the link arm 172 are pivotally attached to the link arm bracket 174 and the tilt center 176 of the cab 180, respectively. By attaching the link arm 172, it is possible to prevent the cab 180 from moving in the vehicle body longitudinal direction from the vehicle body frame 171 when the cab 180 is tilted. In order to perform the cab tilt operation, a cab tilt actuator 175 is installed between the cab 180 and the body frame 171, and a lost motion link 178 is pivotally attached to a side end of the cab 180 of the cab tilt actuator 175. The department is pivotally attached to cab 180. The other end of the cab tilt actuator 175 is pivotally attached to the vehicle body frame 171.

Further, a cab tilt and suspension device for a truck disclosed in Japanese Utility Model Laid-Open No. 60-87877 will be outlined with reference to FIG.

In FIG. 11, the truck cavit and suspension system is shown. This device is provided on both sides of the cab 190 in the vehicle width direction with the cab 190 and the body frame 194.
And a pair of tilt hydraulic cylinders 196 for tilting a cab 190 interposed between the tilt hydraulic cylinders 196 and. This device includes a tilt operation valve 19 that controls up and down operations of a hydraulic pump 191 and a cab 190 in order to supply operating pressure oil to a tilt hydraulic cylinder 196.
3 and tilt operation valve 193 and a pair of tilt hydraulic cylinders 19
A switching valve 195 is provided which is provided in either one of the parallel pressure oil circuits communicating with 6 and which reverses the flow direction of the working pressure oil to that during the cab lifting operation.

[Problems to be solved by the invention]

However, the actuator 140 shown in FIG.
Attached to the shock absorber 173 part of the cab tilt suspension as shown in the figure, removing the coil spring 177 and constructing the tilt cab suspension, using an electric oil pump, sensor, etc. together, the occupant in the cab It is possible to prevent changes in the buffer clearance due to changes in the number of items and the weight of the load, and to prevent bottoming out of the buffer clearance due to displacement of the cab while driving, which has the advantage of significantly improving the riding comfort performance of the cab suspension. The tilt still has to use a hydraulic cylinder or the like, and it is difficult to reduce the weight and the number of parts, and the cost is inevitable.

Further, when the actuator 140 shown in FIG. 10 is used as a hydraulic tilt cylinder, the actuator 140 does not have a retracting function, so that, for example, when the vehicle tilts on a sloping ground, the vehicle tilts forward. As a result, when the center of gravity 179 of the cab exceeds the tilt center 176, it becomes difficult to restore it.
In particular, when the tilt operation is performed even on level ground due to the roof rack on the cab roof, loading of the hood, etc., the position of the center of gravity of the cab may exceed the tilt center. It will be impossible. Further, the actuator 140 having the above-mentioned spring action
Is placed at the shock absorber 173, the coil spring 177 is abolished, and the cab suspension is formed.
Simultaneously tilt the cab with the actuator 140 (tilt forward)
However, since the cab suspension mechanism and the cab tilt mechanism are used as separate mechanisms, the number of parts increases and the weight becomes heavy.

The truck cavitating and suspension device shown in FIG. 11 uses a double-acting cylinder to perform roll control and a tilt function, and does not have a function as a spring.

The purpose of this invention is to solve the above problems,
An actuator equipped with a hydraulic circuit that absorbs vibrations of the vehicle body by the flow of liquid and elasticity of gas and has a retracting function is applied to the cab suspension. For cab-over type vehicles, the actuator also has a cab suspension function and a cab tilt function. By using the retracting function of the actuator, even if the center of gravity of the cab exceeds the tilt center due to forward tilt, etc., the cab can be restored to improve the riding comfort performance and to be used as a dual purpose. It is an object of the present invention to provide a cab tilt / suspension device capable of significantly reducing the number of parts, reducing the weight, and reducing the cost.

[Means for solving problems]

The present invention is configured as follows to achieve the above object. That is, the present invention relates to a link arm having one end pivotally attached to a tilt center of a cab mounted on a vehicle body frame and the other end pivotally attached to a cab foot attached to the cab, and the link arm and the vehicle body frame. An actuator arranged between the actuator and a hydraulic circuit for supplying oil to a contracted oil chamber and an extended oil chamber formed in a cylinder of the actuator, wherein the actuator comprises:
A cylinder body, which is slidably disposed in the cylinder, accommodates a partition piston that partitions the gas chamber and the oil chamber, and has an orifice that communicates with the oil chamber and the extending oil chamber, the cylinder, and the cylinder body. A free piston that is slidably fitted between the cylinder and the partition to divide the inside of the cylinder into the compressed oil chamber and the extended oil chamber; the cylinder inner end of the cylinder and the compressed oil chamber side end of the cylinder. And a first and a second stopper that are provided on each of the first and second stoppers for restricting the movement of the free piston, respectively.

Further, the actuator has one end rotatably attached to a pivotally connecting portion between the cab foot and the link arm,
The other end is attached to the body frame.

Further, the hydraulic circuit includes a line that connects the reduced oil chamber and the electric oil pump via an electromagnetic switching valve and a pilot check valve, and the extension oil chamber and the electric motor via the electromagnetic switching valve and a pilot check valve. It has a line communicating with the oil pump.

Further, the hydraulic circuit is controlled in response to a signal from a level sensor having one end attached to the tilt center of the vehicle body frame and the other end attached to the cab.

Further, a cushion rubber is attached near the tilt center at the front end of the link arm. A rebound rubber is attached to the rear end of the link arm.

[Action]

The cab tilt suspension device according to the present invention is configured as described above, and operates as follows. That is, in this cab tilt suspension device, one end of a hydropneumatic actuator having a retracting function is rotatably attached to a tilt center and a link arm pivotally attached to a cab foot, and the other end of the actuator is attached to a vehicle body frame. Since it is attached, the vibration of the vehicle body is absorbed by the flow of liquid and the elasticity of gas.

Further, by controlling the supply of hydraulic pressure to the actuator from the hydraulic circuit, the cab can be forcibly tilted and restored. Moreover, since the actuator has the retracting function, even if the center of gravity of the cab may exceed the tilt center at the time of tilting the cab, the cab tilt down operation, that is, the restoring operation can be easily performed. Further, since a cushion rubber is attached near the tilt center at the front end of the link arm, it is possible to absorb a shock when the vehicle bounces, and since a rebound rubber is attached to the rear end of the link arm, It is possible to absorb the shock at the time of cab up.

〔Example〕

An embodiment of a hydropneumatic suspension device applied to a cab tilt suspension device according to the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, the actuator 10 in this hydropneumatic suspension device comprises a cylinder 1 and a cylinder 2 inserted in the cylinder 1. The cylinder 1 and the cylinder 2 are sized so as to form an oil chamber between the cylinder 1 and the cylinder 2. A mounting portion 20 is provided at one end of the cylinder 1, and a mounting portion 19 is provided at one end of the tubular body 2. A partition piston 5 for partitioning a gas chamber 8 and an oil chamber 9 is slidably accommodated in the cylindrical body 2 while keeping a sealed state, and has an orifice 3 at the other end (inner end of the cylinder) of the cylindrical body 2. The orifice block 26 is fixed. A sealing member 11 that seals between the cylinder 1 and the cylinder 2 is attached to the other end of the cylinder 1. An annular free piston 4 is slidably fitted between the cylindrical body 2 and the cylinder 1 while maintaining a sealed state,
The inside of the cylinder 1 is partitioned into a contraction oil chamber 7 and an expansion oil chamber 6.

In order to limit the movement of the free piston 4 to the extension oil chamber 6 side, the end portion of the orifice block 26 has the first stopper 13
Function as. Free piston 4 is the first stopper 13
And the movement of the free piston 4 is restricted, and the free piston 4 moves integrally with the tubular body 2 in the contact state. Further, the sealing member 11 fixed to the end of the cylinder 1 on the side of the reduced oil chamber 7 functions as a second stopper 14 that limits the movement of the free piston 4 toward the side of the reduced oil chamber 7. When the free piston 4 is in contact with the second stopper 14, the free piston 4 is integrated with the cylinder 1 and moves relative to the cylinder 2. Further, oil is allowed to flow into and out of the compressed oil chamber 7 through the oil port 16 and the pipe line 15 of the cylinder 1, and oil is allowed to flow in and out of the extended oil chamber 6 through the oil port 17 of the cylinder 1. There is. In the figure, 13a indicates a cushion, and the free piston 4
Is to prevent hitting sound when abutting against the stopper 13.

The actuator 10 in the hydropneumatic suspension device applied to this cab tilt suspension device is configured as described above, and the operation when the hydropneumatic suspension 50 is applied to the hydraulic circuit is shown in FIG. This will be described with reference to (a), FIG. 2 (b), FIG. 2 (c) and FIG. 2 (d).

2 (a) and 2 (b) show the state of the hydropneumatic suspension 50 at the time of normal running of a cab-over type vehicle. In this case, the electric oil pump of the hydraulic circuit is shown. 40 is not operating, the free piston 4 is lowered to the lower end of the cylinder 1 by the pressure during the leveling lift operation and is in contact with the second stopper 14, and the volume of the compressed oil chamber 7 is zero.

First, as shown in FIG. 2 (a), when a load W is applied in the direction indicated by the arrow, the actuator 10 is in a stretched state. The oil in the oil chamber 9 of the tubular body 2 moves in the direction indicated by the arrow H, that is, flows out through the orifice 3 into the extending oil chamber 6. In addition, the length of the cylinder 1 and the cylinder 2 in the actuator 10 is longer than the set reference length.

Further, as shown in FIG. 2B, when the load W is applied in the direction indicated by the arrow, the actuator 10 is in a contracted state. The oil in the extending oil chamber 6 moves in the direction indicated by the arrow G, that is, flows through the orifice 3 into the oil chamber 9 of the cylinder 2. The length of the cylinder 10 and the cylinder 2 in the actuator 10 is shorter than the set reference length. In other words, when the vehicle is traveling, the vehicle height has already been set to the set position, and the sensor by the parking switch described later is in the off state, so the electric oil pump 40 does not operate and the oil is not supplied to the actuator 10. . The oil inside the actuator 10 is sealed by the pilot check valves 35 and 36. Due to the displacement of the amplitude caused by the vibration generated when the vehicle is traveling, the oil in the oil chamber 9 of the cylinder 2 and the oil in the extension oil chamber 6 of the cylinder 1 flow out through the orifice 3 of the orifice block 26 as described above. To enter. When the oil flows in and out through the orifice 3, the partition piston 5 moves up and down to compress or expand the gas enclosed in the tubular body 2, and the actuator 10
A spring force is generated in the. Further, a damping force is generated as the oil passes through the orifice 3. In this case, it is necessary to consider ± strokes with respect to the reference set position of the partition piston 5. It is necessary to control by a pressure switch or a stroke sensor of a hydraulic circuit so that a desired load and a gas pressure corresponding to a stroke are obtained.

FIG. 2C shows the case where the cab over-type vehicle is stopped, the cab is tilted, and then the retracting operation is performed to restore the tilted state. Pilot check valves 35,3 when the vehicle is stopped
At 6, the actuator 10, that is, the oil in the extension oil chamber 6 is in a sealed state, and the extension of the actuator 10 due to the reaction force of the contracting force does not occur and is in a locked state.

When restoring the tilted state of the cab, when the retraction / extension switching operation switch is turned on, the electromagnetic switching valve 37 is turned on, the electric oil pump 40 is operated, and the retraction amount of the cylinder 2 is the stroke sensor. Alternatively, in a system in which an electric circuit is regulated by a sensor such as a pressure switch, the electric circuit is turned off by the signal of the sensor, and the retracting operation is terminated, the above actuator is provided.
The case where 10 is applied will be described.

Solenoid selector valve by turning on the retract / extend selector switch
37 turns on and switches to the position shown. As indicated by the arrow M, the electromagnetic oil pump 40 → electromagnetic switching valve 37 →
A circuit of pilot check valve 36 → reduced oil chamber 7 and a circuit of extended oil chamber 6 → pilot check valve 35 → electromagnetic switching valve 37 → reserve tank 39 are formed as shown by arrow E.

Therefore, the oil supplied from the oil pump 40 is supplied to the compressed oil chamber 7 of the actuator 10 through the electromagnetic switching valve 37 and the pilot check valve 36 as shown by the arrow M, and the oil is supplied through the pipe line 44. Opening pressure is applied to the pilot check valve 35 to open the pilot check valve 35. By opening the pilot check valve 35, the extension oil chamber 6 of the actuator 10 communicates with the reserve tank 39 in the atmospheric pressure state through the electromagnetic switching valve 37 as shown by an arrow E.

Therefore, the oil in the extension oil chamber 6 flows out to the reserve tank 39, and the partition piston 5 is moved from the position shown in FIG. 3 (a) to the position shown in FIG. 3 (b) by the pressure of the gas in the gas chamber 8. It moves to the orifice block 26 at the upper end of the body 2, and the oil in the oil chamber 9 in the tubular body 2 is also discharged to the reserve tank 39 through the extending oil chamber 6, and the partition piston 5 contacts the lower surface of the orifice block 26. It becomes a state.

Further, when oil is supplied to the compressed oil chamber 7 as shown by the arrow M, the free piston 4 rises as shown in FIG. Next, as shown in FIG. 2C, the free piston 4 is the orifice block on the side of the compressed oil chamber 7.
It contacts the first stopper 13, which is the lower end of 26. Subsequently, when the oil is supplied to the compressed oil chamber 7, the cylinder 2 and the free piston 4 are integrally lifted. Therefore, a pulling force that pulls the tubular body 2 into the cylinder 1 is generated. The end of the retracting operation is a signal from the sensor set to a value slightly lower than the set pressure of the safety valve (not shown) or a value at which the cab is in contact with a buffer rubber (not shown) attached to the body frame. The power supply 49 of the electric circuit is cut off.

FIG. 2D shows the case where the cab is tilted when the vehicle is stopped, that is, when the cab is lifted. The lift operation will be described with reference to FIG. 4 (a), FIG. 4 (b), FIG. 4 (c) and FIG. 4 (d).

Solenoid switching valve when the retract / extend selector switch is switched to the restore state to put the cab in the tilted state
The electric circuit is configured so that 37 is turned off and moves to the position shown in the figure, and the electric oil pump 40 operates.
The lift amount of the cylinder 2 is regulated by an appropriate sensor,
An electric circuit is configured so that the electric circuit is turned off by the signal of the sensor and the lift operation is ended. The oil supplied from the oil pump 40 is, as shown by the arrow N,
One flows into the extension oil chamber 6 of the actuator 10 through the electromagnetic switching valve 37 and the pilot check valve 35, and the oil applies an opening pressure to the pilot check valve 36 through the pipe line 60 so that the pilot check valve 36 is opened. Open.

Actuator by opening pilot check valve 36
As shown by the arrow F, the compressed oil chamber 7 of 10 is an electromagnetic switching valve.
It communicates with the reserve tank 39 which is in atmospheric pressure through 37. That is, as shown by the arrow N, the electromagnetic oil pump 40, the electromagnetic switching valve 37, the pilot check valve 35, the circuit of the extension oil chamber 6 and the compressed oil chamber 7 as shown by the arrow F.
→ Pilot check valve 36 → Electromagnetic switching valve 37 → Reserve tank 39 circuit is formed. Therefore, the oil passes through the electromagnetic switching valve 37 and pilot check valve 35,
It flows into the extension oil chamber 6 of 10.

When the leveling, that is, the lift operation is started from the state where the actuator 10 is retracted by the retracting operation described above, the free piston 4 and the first stopper 13, which is the lower surface of the oil block 26, are released as shown in FIG. The cylindrical body 2 is in a state of being in contact with the cylinder 1 in the abutting state.

Next, the valve opening pressure acts on the pilot check valve 36 from the pipe line 30, the pilot check valve 36 is opened, and the compressed oil chamber 7 is opened to the atmosphere, so that the free piston 4 moves to the fourth position.
As shown in FIG. (B), the oil immediately moves, the oil flows out from the port 16 of the compressed oil chamber 7 in the direction indicated by the arrow F, and is discharged to the reserve tank 39. As shown in FIG.
It contacts the lower end of the cylinder 1.

Subsequently, when the oil pump 40 is operated and the oil is supplied to the extension oil chamber 6 of the actuator 10, the oil flows from the orifice 3 of the orifice block 26 into the cylindrical body 2 as shown in FIG. As the partition piston 5 begins to move downward into the oil chamber 9 and the oil flows into the tubular body 2, the pressure inside the gas chamber 8 rises, and a lift force starts to be generated on the cab. Furthermore,
A lift corresponding to the set position is generated, the set pressure is detected by a sensor such as a level sensor, the electric circuit power is turned off in response to the signal of the sensor, the electric oil pump 40 is stopped, and the leveling operation, that is, the lift operation. Ends.

FIG. 5 shows the structure of the cab tilt suspension device 100. Body frame 1
One end of the link arm 102 is rotatably attached to the upper end of the tilt bracket 103 rigidly fixed to the 8 and the rotatable attachment point (pivot point) is used as the tilt center 106 when the cab 12 is tilted. To function as.

The one end 20 of the actuator 10 of the hydropneumatic suspension device is rotatably attached to the body frame 18. In addition, the cab foot 104
Is rigidly fixed. The lower end portion of the cab foot 104 and the actuator 10 are
And the other end 19 of the. Tilt center
Cushion rubber on the link arm 102 near 106
101 is attached and the cushion rubber 101 absorbs a shock when the vehicle bounces.

Although not shown, the actuator 10 and the link arm 10
2 and the mounting structure of the cab foot 104 are
When the link arm 102 is sandwiched between the cab foot 104 and the link arm 102 when the link arm 102 sandwiches the actuator 10, and the link arm 102 sandwiches the actuator 10. As described above, the rebound rubber 110 is attached to the other end or rear end of the link arm 102. The rebound rubber 110 absorbs a shock generated when the vehicle rebounds.

Furthermore, when the cab center of gravity 109 is behind the rotatable attachment point, that is, the joint of the cab foot 104, the link arm 102 and the actuator 10, the cab 12 rotates backward (clockwise in the figure) at the time of the cab tilt. Fulfills the function of preventing. Front end of cab 12 and tilt bracket 10
A level sensor 42 such as a stroke sensor is installed between the upper end portion of 3 and the stroke sensor.

Various mechanisms can be applied to the support structure at the rear end of the cab 12, but as an example thereof, a case of being supported by a coil suspension will be described. In the figure, a coil suspension 107 is located behind the cab 12, and the cab 12 is elastically supported by the coil suspension 107. The coil suspension 107 is mounted on the vehicle body frame 1
Cab mount member 105 rigidly fixed to 8 and cab
It is attached via a floating member 114 to the cab lock mechanism 111 attached to the 12th side. The cab lock mechanism 111 is attached to a bracket 113 rigidly fixed to the cab 12 via cab lock pins 112.

In FIG. 6, when the cab 12 is tilted, the tilt angle is increased, and the center of gravity of the cab 109 is shown in front of the tilt center 106 by a solid line.

Next, a circuit diagram when the hydropneumatic suspension 50 is applied to a cab-over type vehicle will be described with reference to FIG. Since the hydraulic circuit is almost the same as the hydraulic circuit described with reference to FIGS. 2 (a) to 2 (d) above, the same reference numerals are given to the same parts, and the duplicate description will be omitted. To do.

One end of the actuator 10 in the hydropneumatic suspension 50 is attached to the cab 12 side,
The other end is attached to the body frame 18 side.
The level sensor 42, which is a stroke sensor, etc.
It is installed between the 12 side and the body frame 18 side, and is configured to detect the vehicle height of the cab 12. The operation motor 51 that operates the electric oil pump 40 is on / off controlled by an operation relay 46. The parking switch 48 is incorporated in series with the sustain switch 43. Solenoid switching valve 37
Is the sustain switch 43 and parking switch
Turned on and off by 48.

The parking switch 48 releases the parking brake so that the sustain switch 43 is erroneously turned on when the vehicle is traveling, or the level sensor 42 detects traveling displacement while the vehicle is traveling and the electric oil pump 40 does not operate. If so, the hydropneumatic suspension system 50 is incorporated into the circuit to deactivate it.

Regarding the hydraulic circuit, the conduit 30 communicating with the extension oil chamber 6 of the actuator 10 connects the extension oil chamber 6 to the electric oil pump 40 or the reserve tank 39 via the pilot check valve 35, the electromagnetic switching valve 37 and the manual switching valve 38. Link. The conduit 32 communicating with the pressure-reduced oil chamber 7 of the actuator 10 connects the pressure-reduced oil chamber 7 to the electric oil pump 40 or the reserve tank via the pilot check valve 36, the electromagnetic switching valve 37 and the manual switching valve 38.
Connect to 39.

The terminal of the level sensor 42 is connected to the operation relay 46 of the electric oil pump 40 via the diode 45, and the other terminal is grounded to the vehicle body via the coil terminal of the sustain switch 43, the parking switch 48 and the operation relay 46. There is. The power supply 49 is connected to the operation motor 51 of the electric oil pump 40 via the operation terminal 54 in the operation relay 46 of the electric oil pump 40, and the current of the power supply 49 is the operation terminal of the sustain switch 43, the parking switch 48 or the operation relay 46. It is made conductive or non-conductive by 54.

Furthermore, the line 22 connecting the level sensor 42 and the operation relay 46
And the line 21 with the built-in sustain switch 43.
A circuit 25 including a cab tilt auto-stop is installed between and.

Although not shown, the circuit 25 including the cab tilt auto stop is not shown in the present application.
A circuit similar to that disclosed in the publication may be used, or a circuit without a lost link down-limit switch in the circuit may be used. Here, the detailed description of the circuit disclosed in Japanese Utility Model Laid-Open No. 60-75179 will be omitted.

Circuit 25 including auto stop for cab tilt is manual tilt main switch 27, tilt alarm buzzer 2
8. The power is restored because the cab stay up-limit switch 29, the tilt-down end switch 33, and the tilt-down end switch 33 at the time of tilting are turned off to bend and stretch following the tilt movement of the cab 12 and support the weight of the cab. It has a power restoration switch 47.

The circuit including the electric circuit and the hydraulic circuit is configured as described above, and operates as follows.

First, a case where the vehicle height of a cab-over type vehicle in a normal state is set will be described. Turn the sustain switch 43 on to the suspension side. The parking switch 48 is turned on only when the parking brake is activated. The level sensor 42 is configured to be turned on until the vehicle height reaches a set height. An electric circuit is formed by turning on the sustain switch 43 and the parking switch 48. The electromagnetic switching valve 37 is turned on, and the electromagnetic switching valve 37 is switched to the hydraulic circuit in the illustrated state.

At the same time, the operation relay 46 of the electric oil pump 40 is operated and the operation motor 51 is operated by the battery, that is, the power source 49,
The electric oil pump 40 starts supplying oil. The manual switching valve 38 is switched to the illustrated down circuit, that is, the cab tilt down circuit (normal traveling state). Oil pipeline
It is supplied to the extension oil chamber 6 of the actuator 10 through 30. Since the valve opening pressure acts on the pilot check valve 36 through the pipe 60, the pilot check valve 36 opens, the free piston 4 of the actuator 10 moves downward, and the oil in the compressed oil chamber 7 passes through the pilot check valve 36 to the reserve tank. It is discharged to 39. Free piston 4 is second
When the actuator 10 comes into contact with the stopper 14 and finishes descending, the actuator 10 receives the load of the cab 12, the oil supply pressure rises, the cylinder 2 extends from the cylinder 1, and the cab 12 is lifted.

The lift operation of the cab 12 ends when the level sensor 42 reaches the set height and is turned off. The supply of oil from the electric oil pump 40 is stopped, the pilot check valve 36 is closed, and the oil is trapped in the actuator 10. This makes hydropneumatic
Functions as the actuator 10 of the suspension. Since the parking switch 48 is provided so as to be turned off when the parking brake is released when the vehicle is running, the vehicle height is not adjusted and it is safe.

Next, the retracting operation or the tilting operation of the actuator 10 is performed by setting the stilt changeover switch 43 to the tilt side off state. The parking switch 48 is on, but the sustain switch
43 is in the tilt side OFF state, the electromagnetic switching valve 37 is in the OFF state, and the solenoid switching valve 37 is switched to the upper portion. Further, the manual switching valve 38 is switched so that the upper portion is in the communicating state.
At the same time, the power restoration switch 47 provided on the selector lever 34
Turns on. The up-limit switch 29 is in the on state because the cab stay is folded.

In this state, the tilt alarm buzzer 28 sounds. By turning on the tilt main switch 27, the electric oil pump 40
And the electric oil pump 40 starts supplying oil. Oil from the electric oil pump 40 is used for manual switching valve 38, solenoid switching valve 37 and pilot check valve.
It is supplied to the extension oil chamber 6 of the actuator 10 via 35. The valve opening pressure acts on the pilot check 36 through the conduit 30 and the conduit 60, and the pilot check valve 36 opens. The free piston 4 of the actuator 10 moves to the lower end, and the oil in the compressed oil chamber 7 is stored in the pilot check valve 36,
Reserve tank through electromagnetic switching valve 37 and manual switching valve 38
It is discharged to 39. Oil is supplied and flows from the extending oil chamber 6 through the orifice 3 into the oil chamber 9 of the cylindrical body 2 to overcome the gas pressure of the partition piston 5 and push it down, so that the actuator 10 continues to extend. The cylinder 2 of the actuator 10 extends from the cylinder 1, and the cab 12 is lifted.

When the cab 12 is lifted to a predetermined height, in other words, when the cab 12 is rotated to a predetermined tilt angle, a limit switch (not shown) provided on the cab stay portion is provided.
The tilt condition is detected by the circuit (line 2
2) turns off and the tilt operation ends. The circuit is turned off and the tilt alarm buzzer 28 is turned off. The electric oil pump 40 stops, oil is sealed in the actuator 10, and the tilted state of the cab 12 is maintained. The diode 45 is incorporated in the circuit in order to prevent current from flowing backward and the solenoid directional control valve 37 from operating.

Next, a case will be described in which the cab 12 is lowered to bring the tilt state to the normal state. The manual switching valve 38 is switched to the down side (lower side) passage by the switching lever 34.
The electromagnetic switching valve 37 is inoperative like the above, and the upper passage is in conduction. The switch of the cab stay section, that is, the up limit switch 29 is manually turned on. The tilt down end switch 33 is ON in the cab tilt state. When the tilt main switch 27 is turned on manually,
The operation relay 46 of the electric oil pump 40 operates and the electric oil pump 40 starts supplying oil. Oil is supplied from the electric oil pump 40 to the reduced oil chamber 7 of the actuator 10 via the manual switching valve 38, the electric switching valve 37 and the pilot check valve 36. The valve opening pressure acts on the pilot check 35 through the pipe 32 and the pipe 44, the pilot check valve 35 is opened, and the extension oil chamber 6 is opened to the atmosphere.

The free piston 4 of the actuator 10 moves to the upper end,
The oil in the extension oil chamber 6 is discharged to the reserve tank 39 through the pilot check valve 35, the electromagnetic switching valve 37 and the manual switching valve 38. The free piston 4 moves upward, and the free piston 4 moves to the first stopper 13 of the orifice block 26.
, A contracting force is generated in the actuator 10, and the cylinder 2 is inserted into the cylinder 1.

The down operation of the cab 12 is a tilt down end switch.
33 turns off and ends. The tilt alarm buzzer 28 is stopped by the end of the tilt operation. Here, when the cab lock mechanism 111 (see FIG. 5) is not locked, the tilt lock buzzer 28 may be configured to give an alarm when the cab lock switch is turned on.
In this state, the free piston 4 remains in contact with the orifice block 26 of the tubular body 2 and performs the vehicle height adjustment operation of the cab 12.

〔The invention's effect〕

The cab tilt suspension device according to the present invention is
With the above configuration, the following effects are obtained. That is, the cab tilt / suspension device is a cylinder that is slidably disposed in a cylinder and that houses a partition piston that divides a gas chamber and an oil chamber and that has an orifice that communicates with the oil chamber and the extended oil chamber. A body, a free piston slidably fitted between the cylinder and the cylinder to partition the inside of the cylinder into the compressed oil chamber and the extended oil chamber, a cylinder inner end of the cylinder and the free piston. An actuator having first and second stoppers respectively provided on the end of the cylinder on the side of the compressed oil chamber and for restricting the movement of the free piston is provided, and one end of the actuator is pivotally attached to the tilt center and the cab foot. Since it is rotatably attached to the link arm and the other end of the actuator is attached to the vehicle body frame, vibration of the vehicle body is caused by the flow of liquid. And by the elasticity of the gas it can be absorbed, thereby improving the comfort performance of the cab. Further, by controlling the supply of hydraulic pressure to the actuator from the hydraulic circuit, the cab can be forcibly tilted and restored. Moreover, since the actuator has the retracting function, even if the center of gravity of the cab may exceed the tilt center at the time of tilting the cab, the cab tilt down operation, that is, the restoring operation can be easily performed.

Since the actuator has both the cab suspension function and the cab tilt function, the number of parts can be reduced, the weight can be reduced, the cost can be reduced, and a highly reliable device can be provided. Further, by using the level sensor, the cab setting position can be kept constant even when the cab weight changes, and the riding comfort performance can be improved. Furthermore, since a cushion rubber is attached near the tilt center at the front end of the link arm, it is possible to absorb a shock when the vehicle bounces, and since a rebound rubber is attached to the rear end of the link arm, a cab is formed. It is possible to absorb a shock at the time of up, and to prevent the cab from rotating backward when the center of gravity of the cab is behind the connecting portion of the link arm and the cab at the time of tilting the cab.

[Brief description of drawings]

FIG. 1 is a sectional view showing an actuator of a hydropneumatic suspension device used in a cab tilt suspension device according to the present invention, FIG. 2 (a), FIG. 2 (b), FIG. 2 (c) and FIG. Figure 2 (d)
Is a schematic sectional view showing an operating state of the actuator of FIG. 1, FIGS. 3 (a) and 3 (b) are schematic sectional views showing an operating state of the actuator of FIG. 2 (c), and FIG. B), FIG. 4 (b), FIG. 4 (c) and FIG. 4 (d)
2 is a schematic sectional view showing an operating state of the actuator of FIG. 2D, FIG. 5 is a schematic view showing a state in which the cab tilt suspension device according to the present invention is applied to a cab-over type vehicle, and FIG. FIG. 5 is a schematic view showing an example of a tilt operation state, FIG. 7 is a circuit diagram showing an electric circuit and a hydraulic circuit of a hydropneumatic suspension device applied to the cab tilt suspension device according to the present invention, and FIG. Sectional view showing a conventional hydropneumatic suspension actuator,
9 is a sectional view showing an actuator of a conventional vehicle height adjusting device, FIG. 10 is a schematic view showing a cab tilt suspension device of a conventional cab-over type vehicle, and FIG.
FIG. 11 is a schematic configuration diagram showing a conventional truck cavitating and suspension device. 1 ... Cylinder, 2 ... Cylindrical body, 3 ... Orifice, 4 ...
… Free piston, 5… Partition piston, 6… Extension oil chamber, 7… Compressed oil chamber, 8… Gas chamber, 9… Oil chamber, 10… Actuator, 12… Cab, 13… No. 1
, 14 …… Second stopper, 18 …… Vehicle frame, 21,22,23,24 …… Line, 35,36 …… Pilot check valve, 37 …… Electromagnetic switching valve, 40 …… Electric oil pump ,
42 …… Level sensor, 100 …… Cab tilt suspension system, 101 …… Cushion rubber, 102 …… Link arm, 104 …… Cab foot, 106 …… Tilt center, 110 …… Rebound rubber.

Claims (6)

[Claims] 1. A link arm pivotally attached at one end to a tilt center of a cab mounted on a vehicle body frame and at the other end to a cab foot attached to the cab, and between the link arm and the vehicle body frame. A hydraulic circuit for supplying oil to a compressed oil chamber and an extended oil chamber formed in a cylinder of the actuator, and the actuator is slidably arranged in the cylinder and includes a gas. A cylinder that accommodates a partition piston that partitions the chamber into an oil chamber and that has an orifice that communicates with the oil chamber and the extending oil chamber; and the cylinder that is slidably fitted between the cylinder and the cylinder. A free piston that divides the inside into the compressed oil chamber and the extended oil chamber, the cylinder inner end of the cylinder and the compressed oil chamber side of the cylinder Parts and cab tilt suspension apparatus characterized by having a first and a second stopper for limiting each movement of the free piston provided in each. 2. The actuator according to claim 1, wherein one end of the actuator is rotatably attached to a pivotally connecting portion between the cab foot and the link arm, and the other end is attached to the vehicle body frame. Cab tilt described in
Suspension device. 3. The hydraulic circuit includes a line that connects the reduced oil chamber and an electric oil pump through an electromagnetic switching valve and a pilot check valve, and the extension oil chamber through the electromagnetic switching valve and a pilot check valve. The cab tilt / suspension device according to claim 1, further comprising a line that communicates with the electric oil pump. 4. The hydraulic circuit is controlled in response to a signal from a level sensor having one end attached to the tilt center of the vehicle body frame and the other end attached to a cab. The cab tilt suspension device according to the third section. 5. The cab tilt / suspension device according to claim 1, further comprising a knottion rubber attached to the front end of the link arm near the tilt center. 6. A rebound rubber is attached to a rear end portion of the link arm.
The cab tilt suspension device according to the item.