JP4431445B2 - Air suspension device - Google Patents

Description

  The present invention relates to an air suspension device for a vehicle.

Some vehicle air suspension devices can maintain the vehicle height at a target level by supplying and discharging compressed air from an air spring suspended between a vehicle body and wheels. Patent Document 1 discloses a control unit that controls the vehicle height to a target level, and a controller that can arbitrarily manually adjust the target level of the front and rear axles of the vehicle height. In Patent Document 2, in order to deal with jack-up, when compressed air of the air spring is discharged to reduce the vehicle height and the vehicle height is rising regardless of this, it is determined that the jack is up. Disclosed is a control in which the control for reducing the vehicle height to the target level (reference vehicle height) (vehicle height down control for discharging compressed air from the air spring) is stopped.
JP2002-1992928 JP-A-7-246820

  In an air suspension device for a vehicle equipped with an outrigger such as a crane vehicle, when the vehicle body is lifted by the operation of the outrigger, the wheels are suspended from the vehicle body via an air spring. When the air suspension device is equipped with a control unit (control unit) that supplies and discharges compressed air from the air spring so that the vehicle height matches the target level, the compressed air from the air spring is discharged to prevent the vehicle height from rising due to the operation of the outrigger. The air spring is stretched between the vehicle body and the wheel. When the outrigger operation is released, the air spring is now compressed as the vehicle height decreases.When the vehicle height falls below the target level, the supply of compressed air to the air spring is started. An air spring that is deformed unnaturally due to the escape of air may generate a loud noise when it is returned to its original shape even when it is supplied with compressed air. In other words, it is considered that the operation of the outrigger and the release thereof may place a burden on the air spring that causes a loud noise, which may cause early breakage of the air spring.

  An object of this invention is to provide an effective means for solving such a problem.

The first invention includes an air spring suspended between a vehicle body and a wheel, a valve mechanism interposed in an air circuit connecting the air spring and the air tank, means for detecting the vehicle height, and a target level of the vehicle height. PTO connected to a hydraulic pump that supplies driving force such as outriggers, means for controlling the valve mechanism to supply and discharge compressed air from the air spring so that the detected value of the vehicle height matches the target level , Means to keep the target level of the vehicle height at the maximum adjustable state during the PTO operation, and when the detected value of the vehicle height reaches the target level during the PTO operation, the air is released until the PTO operation is released Means for controlling the valve mechanism to cut off the supply and discharge of the compressed air to and from the spring.

The second invention is an air spring suspended between the vehicle body and the wheel, a valve mechanism to be controlled by the control unit, a means for detecting the vehicle height, a means for selecting a target level of the vehicle height, a drive for an outrigger, etc. PTO connected to the hydraulic pump supplying power, PTO switch for operating PTO intermittently, brake switch for detecting brake operation, wiring connecting brake signal terminal of control unit and PTO switch, PTO switch Means for maintaining the target level of the vehicle height at a selectable state of the highest level that can be adjusted when is ON, while the control unit performs normal leveling control that matches the detected value of the vehicle height with the target level. to means for controlling the valve mechanism so as to supply and discharge the compressed air in the air springs, brake signal terminal and PTO switch is oN during PTO actuation Means input is turned ON therebetween for controlling the valve mechanism so as to cut off the supply and discharge of compressed air to the air springs in order to execute a vehicle body attitude change suppressing control, the brake signal terminal PTO switch is ON during PTO actuation When the vehicle height target level is switched to the highest adjustable level at the same time as the vehicle input is turned on, priority is given to the execution of normal leveling control , while the vehicle body posture change suppression control is executed, the vehicle height detection value reaches the target level. Means for delaying until it is reached.

The third invention is the first invention or the second invention, the valve mechanism during the Kyuhaiben, an air spring and the supply and discharge valves interposed air circuit connecting between the air spring and air tank A normally closed shut-off valve interposed in an air circuit connecting the two.

  According to the first aspect of the invention, the valve mechanism is normally controlled so that the compressed air of the air spring is supplied and discharged so that the vehicle height matches the target level, and the vehicle height is maintained at the target level. When the PTO is activated, the target level of the vehicle height is kept at the highest level that can be adjusted, and when the vehicle height falls below the maximum level, compressed air is supplied to the air spring. The supply / exhaust of compressed air is shut off until is released. In this state, when the outrigger is activated, the vehicle body is lifted to a predetermined holding position by the extension of the outrigger. However, since the air spring is extended from the longest adjustment range, the deformation caused by the extension (lift-up) of the outrigger is reduced. It can be suppressed. When the operation of the outrigger is released, the air spring naturally returns to its original shape (longest state) as the vehicle body descends due to contraction of the outrigger. When the PTO operation is released, the highest level is released and the original target level is restored, so the compressed air from the air spring is discharged and the vehicle height is lowered to the target level. This control keeps the vehicle height at the maximum adjustable level while the PTO is in operation, so that the deformation (load) of the air spring that accompanies the operation of the outrigger and its release (shrinkage) can be kept small. The effect that durability can be ensured favorable is acquired.

  According to the second aspect of the invention, the valve mechanism is normally controlled so as to supply and discharge the compressed air of the air spring so that the detected value of the vehicle height matches the selected target level, and the vehicle height is maintained at the target level. . When the input of the brake signal terminal is turned on by the operation of the brake, the valve mechanism is controlled to cut off the supply and discharge of the compressed air during that period, and the change in the posture of the vehicle body caused by braking can be suppressed to a small level. When the PTO switch is turned on (ON) when the PTO is activated and the brake signal terminal input is turned on, at the same time the target level of the vehicle height is switched to the maximum adjustable level, control is performed to match the vehicle height with the target level. Priority is given to the execution of the control that shuts off the supply and discharge of compressed air. The vehicle is delayed until the vehicle height reaches the target level, so compressed air is supplied to the air spring, and when the maximum level is reached, the PTO operation is released. In the meantime, the supply and discharge of compressed air is cut off. In this state, when the outrigger is activated, the vehicle body is lifted to a predetermined holding position by the extension of the outrigger. However, since the air spring is extended from the longest adjustment range, the deformation caused by the extension (lift-up) of the outrigger is reduced. It can be suppressed. When the operation of the outrigger is released, the air spring naturally returns to its original shape (longest state) as the vehicle body descends due to contraction of the outrigger. When the PTO operation is released, the highest level is released and the original target level is restored, so the compressed air from the air spring is discharged and the vehicle height is lowered to the target level. By such control, as in the first aspect of the invention, the deformation (load) of the air spring accompanying the operation of the outrigger and its release (shrinkage) can be kept small, and the effect that the durability can be secured satisfactorily can be obtained.

According to the second aspect of the invention, the control unit controls the valve mechanism so as to supply and discharge the compressed air of the air spring so as to execute normal leveling control for matching the detected value of the vehicle height with the target level, the brake signal In the air suspension device comprising a means for controlling the valve mechanism so as to shut off the supply and discharge of compressed air to the air spring so as to execute the vehicle body posture change suppression control when the input of the terminal is turned on, the brake of the control unit The wiring that connects the signal terminal and the PTO switch, the means to keep the target level of the vehicle height at the highest level that can be adjusted when the PTO switch is ON, and the brake signal terminal input are turned ON When switched to the highest target level is adjustable in height at the same time that excellent execution of normal Riberingu control The simple and easy corresponding execution of the vehicle body attitude change suppressing control while setting the means for delaying until the detection value of the vehicle height reaches the target level to the control unit, the deterioration of the air spring associated with actuation and release of outrigger It can be prevented appropriately.

According to the third aspect of the invention, the valve mechanism that can switch the air circuit connecting the air spring and the air tank in three ways of the supply state, the exhaust state, and the cutoff state by the supply / discharge valve and the normally closed cutoff valve. Can be realized easily and inexpensively.

  The figure explains an embodiment relating to application of the present invention to a rear wheel 2-shaft crane truck. In FIG. 1, reference numeral 10 denotes a frame (vehicle body), and air springs 13La to 13Ld and 13Ra to 13Rd (air bellows) are interposed between the vehicle body 10 and the rear front wheel 11 and the rear rear wheel 12. The air springs 13La to 13Ld and 13Ra to 13Rd are arranged in a pair of left and right on the front and rear of the rear front shaft and on the front and rear of the rear rear shaft. Outriggers 14La, 14Lb, 14Ra, and 14Rb for supporting the vehicle body 10 (frame) on the road surface during crane work are provided in pairs of left and right.

  The cranes and outriggers 14La, 14Lb, 14Ra, and 14Rb are driven by power (hydraulic pressure) generated by a hydraulic pump. A PTO (power take-off device) is provided in the power transmission path of the engine, and a hydraulic pump is connected to the output shaft. A PTO switch for operating PTO is provided. When the PTO is connected by turning on the PTO switch, power is transmitted from the power transmission path to the hydraulic pump. When the PTO switch is turned off, the PTO connection is released and power is transmitted. Transmission of power from the path to the hydraulic pump is interrupted.

  In FIG. 2, reference numeral 15 denotes a compressed air supply source (air tank), and a valve mechanism 20 is interposed in a circuit 16 (air circuit) connecting the air springs 13 La to 13 Ld, 13 Ra to 13 Rd and the air tank 15. The circuit 16 is formed from a merging pipe 16a on the air tank 15 side and branch pipes 16b and 16c branched to the left and right air springs 13La to 13Ld and 13Ra to 13Rd. The valve mechanism 20 includes a two-position three-port electromagnetic supply / discharge valve 21 interposed in the merging pipe 16a, a normally closed electromagnetic shut-off valve 22a interposed in the branch pipe 16b, and a branch pipe 16c. And a pilot shut-off valve 22b. The electromagnetic shut-off valve 22a includes a pilot pressure generating mechanism that opens and closes the pilot shut-off valve 22b in synchronization with ON / OFF of the solenoid.

  The valve mechanism 20 includes an air tank 15 and air springs 13La to 13Ld and 13Ra to 13Rd when the electromagnetic supply / discharge valve 21 is turned on when the normally closed electromagnetic shut-off valve 22a is ON (the shut-off valves 22a and 22b are both opened). The air supply state communicates with the air supply, the exhaust state in which the compressed air of the air springs 13La to 13Ld and 13Ra to 13Rd is released when the electromagnetic supply / discharge valve 21 is turned off, and the normally closed electromagnetic shutoff valve 22a is turned off (cut off) When the valves 22a and 22b are both closed), the circuit 16 is selectively switched to a shut-off state in which supply and discharge of compressed air to the air springs 13La to 13Ld and 13Ra to 13Rd are stopped. An orifice 18 is provided between the branch pipe 16b and the branch pipe 16c to suppress a change in the posture of the vehicle body from side to side.

  The control unit 25 controls the switching of the valve mechanism 20 and includes a signal terminal 26a of the height sensor 26, a brake signal terminal 27a, and a standard level terminal 31a connected to the vehicle height adjusting relay 31. The height sensor 26 is attached to the vehicle body 10 and detects the vehicle height from the rotation angle of the sensing lever 39 that swings according to the distance from the axle side, and outputs an electric signal corresponding to the vehicle height to the control unit 25. To do.

  In FIG. 3, a stop lamp circuit 27 of the vehicle is connected to a brake signal terminal 27a of the control unit 25. The stop lamp circuit 27 includes stop lamp switches 28 and 29 (brake switches) that are turned on when the brake is operated, a stop lamp relay 30 in which the coil is operated (contacts are closed) when the stop lamp switch 28 is turned on, and a stop lamp switch. 28 and 29, and a stop lamp (not shown) that is turned on when energized via the stop lamp relay 30, and an ON-OFF signal of the stop lamp switch 28 is sent to the brake signal terminal 27a of the control unit 25. Entered.

  The vehicle height adjusting relay 31 constitutes a means for selecting a target level of the vehicle height together with a vehicle height adjusting device (not shown). When the target level is selected by the vehicle height adjusting device, the contact point is selected accordingly. Closed. In the case shown in the figure, the control unit 25 determines that the standard level selection state is established by closing the contact 4 of the standard level terminal 31a. It is determined that

  Reference numeral 35 denotes a PTO relay interposed in the electric circuit of the PTO. When the clutch switch is turned on by disconnection of the clutch (interposed in the power transmission path of the engine), the coil is activated (contacts are closed). When the PTO switch (not shown) is turned on while the clutch is stopped, the PTO magnetic valve 36 is energized, and the hydraulic pump connected to the output shaft of the PTO is driven. When the PTO switch is turned OFF, the energization of the PTO magnetic valve 36 is stopped, and the power transmission to the PTO hydraulic pump is interrupted.

  Wiring 37 connecting between the ON terminal of the PTO relay 35 and the brake signal terminal 27a of the control unit 25, wiring 38 connecting between the ON terminal of the PTO relay 35 and the coil terminal of the vehicle height adjusting relay 31 (PTO switch is ON) In this case, a means for keeping the target level of the vehicle height at a selectable state of the highest level that can be adjusted) is applied. Thus, when the PTO switch is turned on, the signal is input to the brake signal terminal 27a of the control unit 25 via the PTO relay 35 and the wiring 37. At the same time, the coil of the vehicle height adjusting relay 31 is energized via the wiring 38, and the contact 5 is closed or held in that state.

  The control unit 25 controls the valve mechanism 20 to supply and discharge the compressed air of the air springs 13La to 13Ld and 13Ra to 13Rd so that the vehicle height matches the selected target level based on the detection signal of the height sensor 26. (Normal leveling control means), means for controlling the valve mechanism 20 to stop the supply and discharge of compressed air to the air springs 13La to 13Ld, 13Ra to 13Rd during the period when the input of the brake signal terminal 27a is turned on (change in posture of the vehicle body) If the standard level terminal 31a is grounded at the same time as the input of the brake signal terminal 27a is turned ON, the target level is switched, and the vehicle body posture change suppression control is given priority over the execution of the normal leveling control. A means for delaying execution until the vehicle height reaches a target level (maximum level) is set.

  With such a configuration, the vehicle height is maintained constant by the leveling control means during normal times even if the loading amount changes. When the brake is actuated, the change in posture of the vehicle body caused by braking can be suppressed to a small level by the posture change suppression control means of the vehicle body.

  During crane work, the PTO switch is turned on (ON) by the operator while the engine is running and the clutch is stopped. When the PTO switch is turned ON, the input of the brake signal terminal 27a is turned ON by energization from the ON terminal of the PTO relay 35 via the wiring 37, and at the same time, the coil of the vehicle height adjusting relay 31 is energized via the wiring 38, and the contact When the standard level terminal 31a is grounded due to the closing of 5, the control unit 25 gives priority to the execution of the normal leveling control, and the vehicle height is set to the target level (the highest level) in the execution of the vehicle body posture change suppression control. Means to delay until it works.

  Therefore, until the vehicle height reaches the maximum level, the valve mechanism 20 is maintained in the air supply state by the normal leveling control means, and when the vehicle height reaches the maximum level, the brake signal terminal 27a is turned off by turning off the PTO switch. Until the input is turned OFF, the electromagnetic shut-off valve 22a and the pilot shut-off valve 22b are maintained in the shut-off state in which they are closed. The air springs 13La to 13Ld and 13Ra to 13Rd swell to the longest state of the adjustment range and support the vehicle height at the highest level. In this state, when the outriggers 14La, 14Lb, 14Ra, and 14Rb are actuated, the vehicle body is lifted by the extension of the outriggers 14La, 14Lb, 14Ra, and 14Rb. However, the air spring is in a predetermined holding position (see FIG. 1) or more. Since 13La to 13Ld and 13Ra to 13Rd are stretched from the longest state, deformation caused by expansion (lift-up) of the outriggers 14La, 14Lb, 14Ra, and 14Rb can be suppressed to a small level. When the outriggers 14La, 14Lb, 14Ra, and 14Rb are deactivated, the air springs 13La to 13Ld and 13Ra to 13Rd return to their original shape (the longest state) as the vehicle body descends due to the contraction of the outriggers 14La, 14Lb, 14Ra, and 14Rb. ) Will return to nature naturally.

  When the crane operation is completed and the PTO switch is turned OFF, the vehicle body posture change suppression control is canceled and the vehicle height adjustment relay 31 selection state is also returned to the standard level, so the vehicle height is lowered to the standard level by normal leveling control. Therefore, the compressed air of the air springs 13La to 13Ld and 13Ra to 13Rd is discharged, and the vehicle height is maintained at the standard level.

  By such control, the deformation (load) of the air springs 13La to 13Ld and 13Ra to 13Rd associated with the operation of the outriggers 14La, 14Lb, 14Ra, and 14Rb and their release (shrinkage) can be suppressed to a small level, and the durability can be secured well. The effect that it can be obtained. In the air suspension device in which the control unit 25 includes normal leveling control means and body posture change suppression control means, the wiring 37 and the PTO relay that connect between the ON terminal of the PTO relay 35 and the brake signal terminal 27a of the control unit 25 While the wiring 38 that connects between the 35 ON terminal and the coil terminal of the vehicle height adjusting relay 31 is added, when the input of the brake signal terminal 27a is turned ON and the target level selection state switches to the highest level, Execution of vehicle body posture change suppression control while giving priority to execution of leveling control is a simple and easy response by setting the control unit 25 to delay until the vehicle height reaches the target level, and the outriggers 14La, 14Lb, 14Ra, 14Rb Therefore, it is possible to prevent the air springs 13La to 13Ld and 13Ra to 13Rd from being deteriorated with proper operation and release.

It is a partial side view of a vehicle. It is a partial block diagram of an air suspension apparatus. It is a one part block diagram concerning the input system of a control unit.

Explanation of symbols

10 Body (frame)
13La to 13Ld, 13Ra to 13Rd Air spring
14La, 14Lb, 14Ra, 14Rb Outrigger
15 Air tank
16 Air circuit
20 Valve mechanism
21 Electromagnetic supply / discharge valve
22a Solenoid shut-off valve
22b Pilot shut-off valve
25 Control unit
26 Height sensor
26a Standard level terminal
27 Stop lamp circuit
27a Brake signal terminal
28, 29 Stop lamp switch
31 Height adjustment relay
35 PTO relay
37, 38 wiring

Claims (3)

  An air spring suspended between the vehicle body and the wheel, a valve mechanism interposed in an air circuit connecting the air spring and the air tank, means for detecting the vehicle height, means for selecting the target level of the vehicle height, vehicle During the operation of PTO, PTO connected to a hydraulic pump that supplies driving force such as outriggers, etc., a means to control the valve mechanism to supply and discharge compressed air of the air spring so that the high detection value matches the target level Means to maintain the target level of the vehicle height at the highest level that can be adjusted.When the detected value of the vehicle height reaches the target level during the PTO operation, supply of compressed air to the air spring until the PTO operation is released. An air suspension device comprising: means for controlling a valve mechanism to block exhaust. An air spring suspended between the vehicle body and the wheel, a valve mechanism to be controlled by the control unit, a means for detecting the vehicle height, a means for selecting a target level of the vehicle height, a hydraulic pump for supplying driving force such as an outrigger PTO connected to the PTO, PTO switch for operating the PTO intermittently, brake switch for detecting brake operation, wiring connecting the brake signal terminal of the control unit and the PTO switch, vehicles when the PTO switch is ON Means for maintaining the target level of the high at a selectable state of the highest level adjustable, while the control unit is adapted to carry out the normal leveling control to match the detected value of the vehicle height with the target level. A means to control the valve mechanism so as to supply and discharge the PTO switch when the PTO is activated and the brake signal terminal input is turned on In the meantime, means to control the valve mechanism so as to cut off the supply and discharge of compressed air to the air spring to execute the body posture change suppression control , the PTO switch is turned on when the PTO is activated, and the brake signal terminal input is turned on At the same time, when the vehicle height target level is switched to the maximum adjustable level, the execution of the vehicle body posture change suppression control is delayed until the detection value of the vehicle height reaches the target level while giving priority to the execution of the normal leveling control . Means. An air suspension device comprising: means.   The valve mechanism includes a supply / discharge valve interposed in an air circuit connecting between the air spring and the air tank, and a normally closed shut-off valve interposed in an air circuit connecting between the air spring and the supply / discharge valve. The air suspension device according to claim 1, wherein the air suspension device is provided.

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