JPH05221214A - Hydraulic suspension device for wheel crane - Google Patents

Abstract

PURPOSE:To make leveling operation automatically without impairing safety in traveling only in the condition where an operator does not feel any trouble, when a vehicle height varies during traveling. CONSTITUTION:Cylinder control parts C1 and C2 for controlling the delivery and exhaust of pressure oil to and from suspension cylinders 1 to 4 are operated and controlled by a controller 11. The controller 11, when vehicle height comes out of a reference value specified for traveling, outputs a cylinder operation request signal to return the vehicle height to the reference value to cylinder control parts C1 and C2, provided that vehicle speed is within a specified low speed range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic suspension device for supporting a vehicle body by a suspension cylinder in a wheel type crane.

[0002]

2. Description of the Related Art In a wheeled crane equipped with a hydraulic suspension device, a suspension cylinder is reduced to lower the vehicle height in order to lower the center of gravity during crane work, or conversely, an approach angle or departure is used when driving on site. An operation such as increasing the vehicle height is performed to increase the angle. On the other hand, during normal (public road) traveling, it is necessary to correct the vehicle height to a legally regulated value (reference value).

Therefore, conventionally, during normal traveling (while traveling is stopped), a cylinder control unit is operated by a switch operation to extend or contract the suspension cylinder to perform a leveling operation for returning the vehicle height to a reference value. ing.

[0004]

However, according to the conventional hydraulic suspension device, since the leveling operation is performed only when the vehicle is stopped, the following problems occur.

(A) During traveling, the hydraulic oil in the suspension cylinder rises in temperature due to exhaust heat of the radiator, brake heat, etc., and expands, so that the suspension cylinder may expand and the vehicle height may increase.

(B) Oil that has become hot during crane operation may enter the suspension cylinder during leveling, which may cool and cool during traveling, causing the cylinder to shrink and lowering the vehicle height.

(C) There is a case where the cylinder is contracted during traveling due to internal leakage of oil in the suspension cylinder or the cylinder control valve, and the vehicle height is lowered.

Since the conventional apparatus cannot cope with such a variation of the vehicle height during traveling, the vehicle height exceeds the reference value, the traveling stability is deteriorated, and the bottoming of the suspension cylinder occurs, so that the vehicle rides. There was a problem of feeling extremely uncomfortable.

Therefore, according to the present invention, when the vehicle height deviates from the reference value during traveling, it is possible to automatically perform the automatic leveling operation for returning the vehicle height to the reference value. (EN) Provided is a hydraulic suspension device for a wheeled crane, which can be operated only under a condition that does not impair the safety and does not make the operator feel uneasy.

[0010]

According to a first aspect of the present invention, there is provided a suspension cylinder provided between an axle and a vehicle body for supporting the vehicle body, and a cylinder control section for controlling supply / discharge of pressure oil to / from the suspension cylinder. A vehicle height detecting means for detecting a vehicle height, a vehicle speed detecting means for detecting a vehicle speed during traveling, and a controller to which a signal from each of these detecting means is input, the controller being (A) On the basis of an input signal from the vehicle height detection means, a vehicle height determination means for determining whether or not the vehicle height deviates from a reference value during traveling, and (B) based on an input signal from the vehicle speed detection means. The vehicle speed discriminating means for discriminating whether or not the vehicle speed deviates from a value set in a predetermined range of the low speed range, and (C) an output means for inputting the discrimination results of these both discriminating means. The output means When the vehicle height deviates from the reference value, the cylinder control unit outputs a cylinder operation command signal in a direction in which the vehicle height returns to the reference value, provided that the vehicle speed is within the set value. It is composed.

According to a second aspect of the present invention, in the structure of the first aspect, the gear shift stage detecting means for detecting the gear shift stage of the transmission and the gear shift stage at the time of starting based on an input signal from the gear shift stage detecting means. A shift speed determination means for determining whether or not the shift speed is other than the shift speed is added, and the cylinder operation command signal from the output means to the cylinder control unit is transmitted to the shift speed other than the shift speed at the start. It is configured so that a certain thing is output as an additional condition.

According to a third aspect of the present invention, in the structure of the first or second aspect, a suspension cylinder is provided for each wheel, and the vehicle height detecting means detects the length of each suspension cylinder. However, pairing the suspension cylinders of two wheels that are diagonally related,
Output the cylinder operation command signal to the cylinder control unit only when the length of the suspension cylinder of this pair deviates from the value set corresponding to the vehicle height reference value in the same direction +-. It is composed.

[0013]

According to the above construction, when the vehicle height deviates from the reference value during traveling, the vehicle height is automatically returned to the reference value by the control operation of the controller based on the signal from the vehicle height detection means. For this reason, it is possible to comply with laws and regulations during traveling, and there is no fear that traveling stability and riding comfort will deteriorate due to vertical variations in vehicle height.

Moreover, since the leveling operation is performed only when the vehicle speed is within the predetermined range of the low speed range, the leveling operation is performed during high speed traveling, which deteriorates the running stability, and the leveling operation causes the driver to feel uncomfortable. There is no fear of anxiety. That is, no adverse effect is caused by the vehicle height correction during traveling.

Further, according to the second aspect of the present invention, the leveling operation is not performed even when the vehicle is traveling at a low speed when the vehicle starts, that is, when the center of gravity moves backward and the rear side is low and the front side is high. On the other hand, according to the third aspect of the invention, leveling is not performed on a slope or a road in which the road surface inclines in the left-right direction in which both cylinders of a pair having a diagonal relationship are deviated from the set value to + and-opposite sides.

That is, according to the structure of the second aspect, it is possible to prevent the erroneous leveling operation at the time of starting, and the structure of the third aspect can prevent the erroneous leveling operation on the slope.

[0017]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the overall construction of the hydraulic suspension system according to this embodiment.

As shown in the figure, suspension cylinders 1, 2, 3 and 4 are provided between the axle and the vehicle body for each of the front left and right wheels and the rear left and right wheels. As a pair, different cylinder control units C1,
Expansion / contraction is controlled by C2.

That is, the pair of front right and rear left cylinders 1 and 4 are controlled by the first cylinder control section C1, and the pair of front left and rear right cylinders 2 and 3 are controlled by the second cylinder control section C2. It

Further, the suspension cylinders 1 to 4 are provided with length sensors 5, 6, 7 and 8 for detecting the lengths of the cylinders 1 to 4 as vehicle height detecting means. The length sensors 5 to 8 are composed of a pair of upper and lower proximity switches, and when the cylinder length is a value set corresponding to the vehicle height reference value, both switches are turned on, and + is set from this set value. When the switch is released to the side or the-side, one of the upper and lower switches is turned off accordingly.

On the other hand, as other detecting means, a vehicle speed sensor 9 for detecting a vehicle speed during traveling and a shift sensor 10 for detecting a gear position (shift position) of the transmission are provided, and these sensors 5 to 8 and 9 are provided. , 10 are input to the controller 11.

As the shift sensor 10, in the case of a crane equipped with an automatic transmission, the shift sensor originally installed for torque converter control can be used. On the other hand, in a crane equipped with a manual transmission, a sensor for detecting the position of the shift lever may be provided.

Both first and second cylinder control units C1 and C
2 has the same configuration. Front right and rear left cylinders 1,
The first cylinder control unit C1 for 4 will be described as an example.

As shown in FIG. 2, the head-side oil chamber 1a of the front right cylinder 1 and the rod-side oil chamber 4b of the rear left cylinder 4 form a pipe line 12, and the rod-side oil chamber 1b of the front right cylinder 1 and the rod-side oil chamber 1b. The head-side oil chamber 4a of the rear left cylinder 4 is connected to each other by a pipe line 13, and the first accumulator 1 is connected to the pipe line 12.
4, the second accumulator 15 is connected to the pipeline 13, and first electromagnetic switching valves (hereinafter, simply referred to as the first switching valves) 16 and 16 are provided in the pipelines 12 and 13, respectively.

The first switching valves 16 and 16 are connected to the pipe 12,
13 and a locked position a for shutting off 13 and a traveling position b for opening the pipelines 12 and 13 are operated by switching.
With the 16 being set to the traveling position b, the vibration during traveling is absorbed by the action of oil in and out (so-called spring action) between the accumulators 14 and 15 and the cylinders 1 and 4. It

On the other hand, during crane work, the switching valve 1
When 6 and 16 are set to the lock position B, the inflow and outflow of the oil is stopped, both cylinders 1 and 4 are locked inoperable, and the vehicle body is fixed to the axle.

Further, between the pipe lines 12 and 13 and the pump circuit 17 and the tank circuit 18, both the second and third electromagnetic switching valves 19, 19 and 20, 20 (hereinafter, simply the second switching valve and the third switching valve) are provided. Valve) is provided.

The second switching valves 19 and 19 block the flow of oil from the pump P to the cylinders 1 and 4 in the first position a, which is a steady position in which the solenoid is not energized, and the cylinders 1 and 4 to the tank are blocked. Only allow oil flow towards T. In the second position (b), on the contrary, only the flow of oil from the pump P toward the cylinders 1, 4 is allowed.

On the other hand, the third switching valves 20, 20 move from the pump P to the cylinders 1 and 1 in the first position a, which is the steady position.
4 performs a check function of allowing only the oil flow toward the tank 4, and allows the oil flow from the cylinders 1 and 4 toward the tank T in the second position B.

These second and third switching valves 19, 20
Is switched by operating a switch (not shown) before traveling, and by a control signal from a controller 11 based on signals from the length sensors 5 to 8, the vehicle speed sensor 9 and the shift sensor 10 during normal traveling. Switching valve 19,
The following operations are performed by the switching operation of 20.

(I) Vehicle body raising action When the solenoid of the second switching valve 19 is energized, the switching valve 1
9 is switched to the second position b, and the pressure oil from the pump P passes through the same position b and the first position a of the third switching valve 20 into the extension side oil chambers 1a and 4a of both cylinders 1 and 4. Supplied. At this time, since the first switching valve 16 is simultaneously energized and switched to the position b, the reduction side oil chambers 1b of the cylinders 1 and 4,
The oil in 4b merges with the pressure oil from the pump P and flows into the extension side oil chambers 1a and 4a of both cylinders 1 and 4. As a result, both cylinders 1 and 4 are extended to raise the vehicle body.

When the energization of the solenoid of the second switching valve 19 is stopped, the switching valve 19 returns to the first position B, so that the supply of pressure oil to the cylinder extension side oil chambers 1a, 4a is stopped. However, at this time, the return of the oil in the oil chambers 1a and 4a is blocked by the third switching valve 20, so that the extension operation of both cylinders 1 and 4 is stopped and the cylinders are held at the positions at this time. ..

(II) Vehicle lowering action The solenoid of the third switching valve 20 is energized and the switching valve 20 is turned on.
Is set to the second position b, the oil in the extension side oil chambers 1a and 4a is moved to the second position of the third switching valve 20 due to the force of the vehicle body weight in the contracting direction which acts on both cylinders 1 and 4. (B) It is discharged to the tank T through the first position (1) of the second switching valve 19. At this time, since the first switching valve 16 is not energized, the oil in the accumulators 15 and 14 is supplied to the reduction side oil chambers 1b and 4b of both cylinders 1 and 4.

Next, the structure and operation of the controller 11 for performing vehicle height adjustment (automatic leveling) during traveling will be described.

As shown in FIG. 3, the controller 11 receives a vehicle height discriminating section 21 to which the cylinder length signals from the length sensors 5 to 8 are input, and a shift speed signal from the shift sensor 10. Shift speed determination unit 22 and vehicle speed sensor 9
The vehicle speed discriminating section 23 to which the vehicle speed signal from the vehicle is inputted, and the second and third switching valves 19, 2 of the cylinder control sections C1, C2 in response to the discrimination results by the respective discriminating sections 21, 22, 23.
The output unit 24 outputs a control signal for 0.

It should be noted that the first switching valve 16 is constantly operated while traveling.
The second position B is set.

In the vehicle height discriminating section 21, either of the pair of front right cylinder 1 and rear left cylinder 4 or the pair of front left cylinder 2 and rear right cylinder 3 is determined based on the cylinder length signal. It is determined whether or not it deviates from the set value in the + and − directions.

On the other hand, in the gear speed discriminating unit 22, the current gear speed of the transmission is a gear speed other than the start gear and a gear speed at low speed running (for example, 2 gears when all gears are 3 gears, hereinafter It will be described in a case).

Further, the vehicle speed discriminating section 23 discriminates whether or not the vehicle speed is within a predetermined range of a low speed region (for example, 3 Km / h or more and less than 10 Km / h, which will be described below in this case).

The output unit 24 is configured to determine the discriminators 21 and 21.
Only when the determination results in 2 and 23 are all YES, the cylinder control command signals to the cylinder control units C1 and C2 for automatic leveling, that is, when the vehicle body needs to be raised, the second switching valve 19 A signal for switching to the position b of 2 or a signal for switching the third switching valve 20 to the second position b is output when the vehicle body needs to be lowered.

Thus, when the vehicle height deviates from the reference value during traveling, the automatic leveling operation for automatically returning the vehicle height to the reference value can be performed. For this reason, it is possible to comply with laws and regulations during traveling, and there is no fear that traveling stability and riding comfort will deteriorate due to vertical variations in vehicle height.

In addition, in this leveling operation, (A) two cylinders in a diagonal relationship are paired, and the lengths of at least one pair of two cylinders deviate from the set value in the + and-directions. (B) Not starting, (C) Low vehicle speed 3km / h or more 10km
Since it is started only when all three conditions of less than / h are satisfied, the following effects are achieved.

I. Due to the condition setting of (A) above, the leveling operation is not performed on a slope road where both cylinders of the pair deviate from the set values to the + and-opposite sides or a road in which the road surface is inclined in the left-right direction. Further, due to the condition setting of (B) above, leveling is not performed even at the time of starting when the center of gravity of the crane moves later.

That is, since the leveling operation is performed only during steady running on a flat road, this leveling can be performed accurately.

II. By setting the condition (C), leveling is not performed during high-speed traveling, so there is no risk of deterioration of high-speed stability due to vertical fluctuation of the center of gravity of the crane.

Further, the leveling is performed in the low speed range of 3 Km / h to 10 Km / h, and the leveling is performed only during the deceleration due to the combination of the set speed and the gear stage (2nd speed) of (B). It is difficult for the operator to feel the fluctuation of the height as an actual feeling, and there is no fear of making the operator feel uneasy.

After the leveling is started under the vehicle speed condition (C), if the vehicle speed deviates from this condition, the leveling may be stopped immediately. However, the traveling without causing the operator to feel uneasy. Stopped state (vehicle speed 0K
m / h), and slight acceleration (for example, 15 Km /
In h), the leveling operation may be continued as it is until completion.

By the way, even when the leveling operation is performed at the time of starting, the vehicle height correction is performed at the stage of shifting to the steady running, so that the condition (B) other than the time of starting is excluded from the starting condition. Good.

Further, even if the leveling operation is performed in a state where the condition (A) is not satisfied, the vehicle height will be corrected again on a flat road. Therefore, the condition (A) is also excluded. Only the vehicle speed may be used as the leveling start condition.

[0051]

As described above, according to the present invention, when the vehicle height deviates from the reference value during traveling, the vehicle height is automatically set to the reference value by the control action of the controller based on the signal from the vehicle height detection means. It is corrected to the value. For this reason, it is possible to comply with laws and regulations during traveling, and there is no fear that traveling stability and riding comfort will deteriorate due to vertical variations in vehicle height.

Moreover, since this automatic leveling operation is performed only when the vehicle speed is within the predetermined range of the low speed range,
There is no fear that the leveling operation will be performed when driving at high speeds and running stability will be deteriorated or that the driver will not feel uneasy. That is, no adverse effect is caused by the vehicle height correction during traveling.

Further, according to the invention of claim 2, the erroneous leveling operation at the time of starting when the center of gravity moves backward, and the invention of claim 3 prevent the erroneous leveling operation on the slope, respectively. The leveling operation can be performed only under the condition that the vehicle height can be accurately detected when traveling at low speed on a flat road.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a hydraulic suspension device according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a cylinder control unit in the same device.

FIG. 3 is a block diagram showing a configuration of a controller in the device.

[Explanation of symbols]

1-4 Suspension cylinder C1, C2 Cylinder control section 5-8 Length sensor as vehicle height detection means for detecting the length of each suspension cylinder 9 Vehicle speed sensor as vehicle speed detection means 10 Shift sensor as gear position detection means 11 Controller 21 Vehicle height discriminating unit (vehicle height discriminating means) 22 Shift stage discriminating portion (shift stage discriminating means) 23 Vehicle speed discriminating portion (vehicle speed discriminating means) 24 Output portion (output means)

Claims (3)

[Claims] 1. A suspension cylinder provided between an axle and a vehicle body for supporting the vehicle body, a cylinder control section for controlling supply and discharge of pressurized oil to and from the suspension cylinder, and a vehicle height detecting means for detecting a vehicle height. A vehicle speed detecting means for detecting a vehicle speed during traveling, and a controller to which signals from the respective detecting means are inputted. This controller is based on (A) the input signal from the vehicle height detecting means. And (B) based on the input signal from the vehicle speed detecting means, the vehicle speed is set within a predetermined range in the low speed range. The vehicle speed discriminating means for discriminating whether or not the vehicle speed deviates from the predetermined value, and (C) the output means for inputting the discrimination results by both of the discriminating means. When it comes off In addition, on condition that the vehicle speed is within the set value, the cylinder control unit is configured to output a cylinder operation command signal in a direction in which the vehicle height returns to a reference value. Crane hydraulic suspension device. 2. The hydraulic suspension device for a wheeled crane according to claim 1, wherein the gear shift stage is started on the basis of a gear shift stage detecting means for detecting the gear stage of the transmission and an input signal from the gear stage detecting means. And a gear shift discriminating means for discriminating whether or not the gear shift gear is other than the gear shift gear at the time of starting the gear shift gear from the output means to the cylinder control unit. A hydraulic suspension device for a wheeled crane, wherein the hydraulic suspension device is configured to be output as an additional condition that it is in a stage. 3. The hydraulic suspension device for a wheeled crane according to claim 1 or 2, wherein a suspension cylinder is provided for each wheel, and a vehicle height detecting means is provided.
The length of each suspension cylinder is detected, and the output means makes a pair of suspension cylinders of two wheels in a diagonal relationship, and the length of the suspension cylinder of this pair corresponds to the reference value of the vehicle height. A hydraulic suspension device for a wheeled crane, which is configured to output a cylinder operation command signal to the cylinder control unit only when the value set by + is deviated in the same direction.