JPH06286446A - Suspension control device for vehicular construction machine - Google Patents

Abstract

PURPOSE:To improve the comfortableness during the front work by effectively damping the pitching vibration caused by the operation of a front work device. CONSTITUTION:A suspension control device is provided with a pressure switch 25 opened or closed by the pilot pressure of a pilot valve 20 operating a front work device FW. When it is detected that the pressure switch 25 is opened by the pilot pressure and the front work device is in operation, solenoid valves 8L, 8R are closed, accumulators 4L, 4R and suspension cylinders 3L, 3R are cut off, and a suspension is locked. When it is detected that the operation of the front work device FW is stopped, the solenoid valves 8L, 8R are opened, the accumulators 4L, 4R and the suspension cylinders 3L, 3R are communicated, and the lock of the suspension is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control device for a vehicle construction machine having a selectively lockable suspension between a chassis and an axle.

[0002]

2. Description of the Related Art As a self-propelled loading and unloading vehicle such as a truck crane, as disclosed in Japanese Utility Model Laid-Open No. 63-12417, a vehicle is mounted between a chassis and an axle in order to improve riding comfort during traveling. 2. Description of the Related Art Conventionally, a suspension equipped with a vibration damping function including a spring and a damper is known. In such a conventional self-propelled cargo handling vehicle,
Usually, the vehicle is fixed to the ground by an outrigger or the like during a suspended load operation with the vehicle stopped, and the suspension and the axle are fixedly connected to each other to lock the suspension to ensure stability when the suspended load is traveling. .

On the other hand, a digging and loading vehicle such as a wheel shovel, as shown in FIGS.
It has a lower traveling structure LC and an upper revolving structure US, and the front working device FW is mounted on the upper revolving structure US. The lower traveling body LC is an axle 2 having traveling tires 1L, 1R.
And a chassis 5. The chassis 5 is suspended on the axle 2 by a suspension having suspension lock cylinders 3L, 3R and accumulators 4L, 4R connected to the suspension lock cylinders 3L, 3R, and is used for traveling. The riding comfort is improved. In an excavation loading vehicle such as a wheel shovel, in order to make the most of the mobility of the vehicle, a fixing means such as an outrigger is hardly used during excavation work, and the suspension is locked to perform work.

[0004]

FIG. 7 shows a model diagram when the suspension of the wheel shovel is locked. A front working device in an excavation loading vehicle such as a wheel shovel has a higher operating speed than a crane or the like. For example, the front working device F shown in FIG.
When the boom B of W is rotated upward and stopped suddenly, the inertia moment of the front working device FW is large, and therefore the inertia causes the torque around the center of gravity of the vehicle body (the lower traveling body LC and the upper swinging body US). T1 and T2 act. Under this front working condition, the suspensions are locked as described above, so that the torques T1 and T2 are absorbed only by the running tires 1L and 1R.

However, since the running tires 1L, 1R generally have a high spring constant and a small damping performance, pitching vibration occurs in which the front and rear wheels alternately vibrate vertically, and it takes time for the vibrations to converge. Deteriorates ride comfort during front work.

An object of the present invention is to effectively damp pitching vibration caused by the operation of a front working device,
An object of the present invention is to provide a suspension control device for a vehicle construction machine that improves riding comfort during front work.

[0007]

The present invention will be described with reference to FIGS. 1 to 6 showing an embodiment. According to the present invention, the suspension 3L which can be selectively locked between a chassis 5 and an axle 2 is provided. Self-propelled vehicle body LC, US having (4L), 3R (4R) and self-propelled vehicle body LC, US
The present invention is applied to a suspension control device for a vehicle-type construction machine equipped with a front working device FW that is mounted on a vehicle and performs excavation and loading. The suspension control device for a vehicle-type construction machine according to claim 1 detects the operation of the front working device FW and the operation detecting device 25 operates the front working device FW. Suspension 3L (4
L), 3R (4R) are locked, and front working device FW
Suspension 3L when the suspension of the
The above object is achieved by including suspension lock control means 8L and 8R for unlocking (4L) and 3R (4R). A suspension control device for a vehicle-based construction machine according to claim 2 is a front working device FW.
An operation detecting means 25 for detecting whether or not the
Suspensions 3L (4L), 3R when the front work device FW is detected to be operating by the load detection means 28 for detecting the load applied to the front work device FW and the motion detection means 25. (4R) is locked, and the suspensions 3L (4L), 3L at a speed corresponding to the load weight detected by the load weight detection means 28 when the operation stop of the front working device FW is detected.
The above object is achieved by including suspension lock control means 29, 9L, 9R for unlocking R (4R).

[0008]

[Action]

-Claim 1- The suspension 3L when the operation detecting means 25 detects that the front working device FW is operating.
(4L) and 3R (4R) are locked, and the suspensions 3L (4L) and 3R (4R) are unlocked when the operation stop of the front working device FW is detected. -Claim 2 -The suspensions 3L (4L) and 3R (4R) are unlocked at a speed corresponding to the loaded load acting on the front work device FW detected by the loaded load detecting means 28.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. It is not limited to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIGS. In the embodiments of the present invention, the same components as those in the above-described conventional example are designated by the same reference numerals as those in the above-described conventional example, and the description thereof will be omitted. FIG. 1 shows an embodiment of a suspension control device for a vehicle construction machine according to the present invention. In FIG. 1, reference numeral 10 denotes a boom driving hydraulic circuit of the front working device FW, and the boom driving hydraulic circuit 10 supplies hydraulic pressure to the bottom chamber 12 and the rod chamber 13 of the boom cylinder 11 that raises and lowers the boom B. It has a hydraulic pilot type control valve 14 for controlling discharge.

The control valve 14 is provided in the bottom chamber 12
Is connected to the hydraulic oil supply passage 16 by the main hydraulic pump 15 to connect the rod chamber 13 to the drain oil passage 17, and the bottom chamber 12 is connected to the drain oil passage 17 to supply hydraulic pressure to the rod chamber 13. The boom lowering operation position connected to the oil passage 16 and the boom operation stop position where both the bottom chamber 12 and the rod chamber 13 are separated from the hydraulic pressure supply oil passage 16 and the drain oil passage 17 to block the bottom chamber 12 and the rod chamber 13 It is a hydraulic pilot type switching valve that switches to three positions. The control valve 14 is switched to a boom ascending operation position when hydraulic pressure is supplied to the pilot conduit 18 and to a boom descending operating position when hydraulic pressure is supplied to the pilot conduit 19, and thus any one of the pilot conduits 18 and 19 is selected. When the hydraulic pressure is not supplied, the neutral boom operation is switched to the stop position.

Hydraulic pressure is supplied to the pilot lines 18 and 19 by a pilot valve 20. The pilot valve 20 is provided in the operator's cab and is provided with an operating lever 21.
When the operating lever 21 is in the neutral position shown in the drawing, both pilot lines 18 and 19 are connected to the drain oil line 17, and the operating lever 21 is tilted upward in the drawing to operate the pilot line. 18 is connected to the hydraulic oil supply passage 23 by the pilot hydraulic pump 22 and the pilot pipe passage 19 is connected to the drain oil passage 17, while the operation lever 21 is tilted downward in the drawing to open the pilot pipe passage 19 The hydraulic oil supply passage 23 is connected to connect the pilot pipe 18 to the drain oil passage 17.

Suspension lock cylinders 3L, 3R
In the middle of the passages 7L, 7R connecting the bottom chambers 6L, 6R to the accumulators 4L, 4R, the passages 7L, 7R
Electromagnetic cutoff valves 8L and 8R that selectively cut off the communication of R are provided. A power source 24 is selectively connected to the solenoid portions of the electromagnetic cutoff valves 8L and 8R according to opening and closing of the pressure switch 25, and the pressure switch 25 is opened when hydraulic pressure is supplied to the oil passage 26, It is a normally closed pressure switch that is closed when hydraulic pressure is not supplied to the oil passage 26. The electromagnetic shutoff valves 8L and 8R establish communication between the passages 7L and 7R when the pressure switch 25 is closed and energize, and shut off communication between the passages 7L and 7R when the pressure switch 25 is open and not energized. The oil passage 26 is connected to the pilot pipe passages 18 and 19 via the shuttle valve 27.

Next, the operation of the embodiment configured as described above will be described. When the operating lever 21 is in the neutral position shown in the drawing, both pilot lines 18 and 19 are connected to the drain oil passage 17, the control valve 14 is in the boom operation stop position, and the boom B is in the operation stop state. At this time, since the hydraulic pressure does not act on the pressure switch 25 and the pressure switch 25 is in the closed state, the solenoid portions of the electromagnetic cutoff valves 8L and 8R are energized, and the electromagnetic cutoff valves 8L and 8R are changed to the spring force from the positions shown in the figure. Switch to the left against the passage 7L, 7R
Establish communication. As a result, when the boom B is stopped, the bottom chambers 6L and 6R of the suspension lock cylinders 3L and 3R communicate with the accumulators 4L and 4R, and the suspension lock is released. That is, when traveling without using the boom, the suspension lock cylinders 3L, 3R and the accumulators 4L, 4L
Vibration is absorbed and suppressed by the suspension composed of R, and the ride is comfortable.

When the operating lever 21 is tilted upward or downward from the neutral position shown in the drawing, the pilot pipe line 18,
Alternatively, the hydraulic pressure is supplied to 19, whereby the control valve 14 is switched to the boom raising operation position or the boom lowering operation position, the hydraulic pressure is supplied to the bottom chamber 12 or the rod chamber 13 of the boom cylinder 11, and the boom B is raised. , Or descent operation. At this time, the oil pressure in the pilot line 18 or 19 is changed to the shuttle valve 27.
Acting on the pressure switch 25 via the
Is opened, the energization of the solenoids of the electromagnetic cutoff valves 8L and 8R is stopped, and the electromagnetic cutoff valves 8L and 8R are switched to the right by the return spring to cut off the communication between the passages 7L and 7R. As a result, when the boom B is operating, the bottom chambers 6L of the suspension lock cylinders 3L, 3R,
6R blocks the communication with the accumulators 4L, 4R, and the suspension is locked.

Therefore, when the boom B of the front working unit FW is being moved, the suspension is locked and the state of the model diagram as shown in FIG. 7 is obtained.
Workability such as excavation work by the front working device FW is secured.

When the operating lever 21 is returned to the neutral position while the boom B of the front working device FW is operating as described above, the operation of the boom B is immediately stopped.
At this time, both the pilot pipe lines 18 and 19 are connected to the drain oil line 17 again, the hydraulic pressure does not act on the pressure switch 25, the pressure switch 25 returns to the closed state, and the solenoid portions of the electromagnetic cutoff valves 8L and 8R are connected. When energized, the electromagnetic cutoff valves 8L and 8R are switched to the left against the return spring. As a result, the suspension is unlocked, and the state of the model diagram as shown in FIG. 2 is obtained. Therefore,
When the operation of the boom B is suddenly stopped, the torques T1 and T2 acting on the vehicle body (the lower traveling body LC and the upper swinging body US) due to the inertia of the front working device FW cause pitching vibrations, but the suspension has damping. Depending on the performance, effective vibration absorption and damping are performed.

FIG. 3 shows another embodiment of the suspension control device for a vehicle construction machine according to the present invention. In addition, in FIG. 3, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof will be omitted. In this embodiment, the solenoid valves 8L and 8R are replaced with proportional solenoid valves 9L and 9L.
R is provided. The proportional solenoid valves 9L, 9R are switched to the positions shown in the figure when not energized to cut off communication between the passages 7L, 7R, and when energized, communicate with the passages 7L, 7R with an opening area proportional to the value of the current supplied to the solenoid. Establish. Therefore, the bottom chamber 12 of the boom cylinder 11
Sensor 28 for detecting the hydraulic pressure P supplied to the
And a current value variable power supply device 29 for adjusting the energization current to a current value A corresponding to the hydraulic pressure P detected by the pressure sensor 28.
Are provided, and current is supplied to the proportional solenoid valves 9L and 9R from the variable current value power supply device 29 via the pressure switch 25.

The variable current value power supply device 29 includes the pressure sensor 2
When the hydraulic pressure P detected by 8 is less than or equal to the first predetermined value P1, the proportional solenoid valves 9L and 9R are fully opened,
When the hydraulic pressure P is greater than or equal to the first predetermined value P1, the proportional solenoid valves 9L, 9L are gradually increased as the hydraulic pressure P increases.
When the opening degree of R is decreased and the hydraulic pressure P is the second predetermined value P2 which is larger than the first predetermined value P1, the proportional solenoid valve 9L,
The current value A is adjusted according to the hydraulic pressure P with the characteristic that the opening of 9R is fully closed.

Also in this embodiment, when the operating lever 21 is tilted upwards or downwards from the neutral position in the drawing and the boom B is moving up or down, pressure is applied by the hydraulic pressure in the pilot conduit 18 or 19. The switch 25 is opened, the energization of the electromagnetic cutoff valves 8L and 8R is stopped, and the passage 7 is opened by the electromagnetic cutoff valves 8L and 8R.
The communication between L and 7R is cut off, and the suspension is locked. When the operation lever 21 is returned to the neutral position and the operation of the boom B is stopped, the hydraulic pressure does not act on the pressure switch 25, and the pressure switch 25 returns to the closed state, so that the current values are supplied to the electromagnetic shutoff valves 8L and 8R. Electric current is supplied from the variable power supply device 29.

For example, the first predetermined value P1 is the maximum boom cylinder holding pressure when the bucket is empty, and the second predetermined value P2 is the boom cylinder holding pressure when the bucket is fully loaded. If the operation of the boom B is stopped while the earth and sand are loaded in the bucket during excavation, the opening degree of the electromagnetic shutoff valves 8L and 8R is set according to the loading load of the bucket at that time. Is quantitatively controlled.

As a result, when the operation of the boom B is stopped while the bucket is loaded with earth and sand, the electromagnetic shutoff valve 8
L and 8R are not fully opened, that is, the suspension lock is not suddenly released, and the electromagnetic shutoff valve 8
The suspension is gradually unlocked due to the throttling effect of the partially opened state of L and 8R, and it is possible to prevent the vehicle body from suddenly sinking due to the loaded weight of the bucket when the suspension is unlocked.

In each of the above-mentioned embodiments, the case where the suspension control device according to the present invention is applied to the suspension using the gas spring by the accumulator has been described, but the suspension control device according to the present invention is the suspension using the gas spring. The present invention is not limited to the above-mentioned application, but is similarly applied to a suspension using another metal spring as long as it has a suspension lock mechanism.

FIG. 4 shows an embodiment applied to a suspension using a metal spring of a suspension control device for a vehicle construction machine according to the present invention. Note that, also in FIG. 4, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof will be omitted. In this embodiment, the bottom chamber 56a of the suspension lock cylinder 53L, 53R is
Pilot check valves 30L and 30R are connected to L and 56aR and rod chambers 56bL and 56bR, respectively.
The pilot check valves 30L and 30R are closed when the pilot hydraulic pressure is not applied from the oil passage 31, and the chambers 56 of the suspension lock cylinders 53L and 53R are closed.
aL, 56aR, 56bL and 56bR are closed to bring them into a suspension lock state, and when pilot oil pressure is being applied from the oil passage 31, the valve is opened and the suspension lock cylinders 53L and 53R each have a chamber 5
6aL, 56aR, 56bL, 56bR are opened to release the suspension lock.

The oil passage 31 is selectively connected to either one of the hydraulic oil supply passage 23 and the drain oil passage 17 by an electromagnetic switching valve 32. The electromagnetic switching valve 32 is selectively supplied with current from the power source 24 in response to opening / closing of the pressure switch 25, and connects the oil passage 31 to the hydraulic oil supply oil passage 23 when energized, while the oil passage 31 is deenergized when not energized. The drain oil passage 17 is connected for communication.

In this embodiment, when the operating lever 21 is tilted upward or downward from the neutral position shown in the drawing and the boom B is moving upward or downward,
The pressure switch 25 is opened by the hydraulic pressure in the pilot conduit 18 or 19, the power supply to the electromagnetic switching valve 32 is stopped, and the oil passage 31 is communicatively connected to the drain oil passage 17. As a result, pilot check valves 30L, 30R
The pilot hydraulic pressure acting on the drain pressure becomes drain pressure, all the pilot check valves 30L and 30R are closed, and each chamber 56aL of the suspension lock cylinders 53L and 53R,
56aR, 56bL, and 56bR are blocked, and the suspension lock state is set.

When the operation lever 21 is returned to the neutral position and the operation of the boom B is stopped, the hydraulic pressure stops acting on the pressure switch 25, and the pressure switch 25 returns to the closed state. When energized, the oil passage 31 is communicatively connected to the oil pressure supply oil passage 23, and the pilot check valve 3
Pilot hydraulic pressure is applied to 0L and 30R. As a result, the pilot check valves 30L and 30R are all opened and the suspension lock is released.

Although the wheel shovel has been described above as an example, the present invention can be applied to any vehicle construction machine having a front working device other than the wheel shovel.

[0029]

As described in detail above, according to the suspension control device for a vehicle construction machine according to the present invention,
The suspension is locked when the operation detecting means such as a pressure sensor detects that the front working device is operating, and the suspension is unlocked when the stop of the operation of the front working device is detected. Pitching vibration resulting from inertia when the work device is stopped is effectively damped, and riding comfort is improved. Further, since the suspension is controlled by the damping force corresponding to the load acting on the front working device detected by the load detecting means to unlock the suspension, the load acting on the front working device when the lock is released. This prevents the vehicle body from suddenly sinking, which also improves riding comfort and safety.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a suspension control device for a vehicle construction machine according to the present invention.

FIG. 2 is a model diagram when a suspension lock of a vehicle construction machine is released.

FIG. 3 is a circuit diagram showing another embodiment of the suspension control device for a vehicle construction machine according to the present invention.

FIG. 4 is a circuit diagram showing another embodiment of a suspension control device for a vehicle construction machine according to the present invention.

FIG. 5 is an overall view showing a general structure of a wheel shovel.

FIG. 6 is a schematic configuration diagram showing a general structure of a wheel shovel suspension.

FIG. 7 is a model diagram of a vehicle construction machine (wheel shovel) when the suspension is locked.

[Explanation of symbols]

 LC Undercarriage US Upper revolving structure FW Front working device 2 Axle 3L, 3R Suspension lock cylinder 4L, 4R Accumulator 5 Chassis 8L, 8R Electromagnetic cutoff valve 9L, 9R Proportional solenoid valve 10 Boom drive hydraulic circuit 11 Boom cylinder 14 Control valve 18, 19 Pilot line 20 Pilot valve 21 Operating lever 25 Pressure switch 28 Pressure sensor 29 Current value variable power supply device 30L, 30R Pilot check valve 32 Electromagnetic switching valve

Claims (2)

[Claims] 1. A self-propelled self-propelled vehicle body having a suspension capable of selectively locking between a chassis and an axle, and a front work device mounted on the self-propelled vehicle body for excavating and loading. In a suspension control device for a vehicle-based construction machine, a motion detection unit that detects whether or not the front work device is operating, and when the operation detection unit detects that the front work device is operating. A suspension control device for a vehicle-based construction machine, comprising: a suspension lock control unit that locks the suspension and unlocks the suspension when an operation stop of the front working device is detected. 2. A self-propelled vehicle body having a suspension capable of selectively locking between a chassis and an axle, and a front working device mounted on the body of the self-propelled vehicle for excavating and loading. In a suspension control device for a vehicle-based construction machine, a motion detection unit that detects whether or not the front work device is operating, a load detection unit that detects a load load acting on the front work device, and The suspension is locked when the operation detecting means detects that the front working device is operating, and the load is detected by the load detecting means when the operation stop of the front working device is detected. Suspension lock control means for unlocking the suspension at a speed according to A suspension control device for a vehicle construction machine, characterized by: