JP2000185534A - Axle fixing control device for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow an operator to select, at his or her discretion as necessary, between locking and unlocking an axle by providing means of selecting the function between an automatic control of locking axle by means of a lock command and a manual forced unlocking of the axle according to vehicle operating conditions. SOLUTION: When an auto mode is selected on a selector switch 14, a controller 10 issues a drive command to open or close a solenoid valve 3, automatically controlling locking or unlocking an axle according to vehicle operating conditions. This ensures stabilized turning and straight-ahead running regardless of a lift value and a side force. When a manual mode is selected on the selector switch 14, a close command voltage is forcibly applied to the solenoid valve 3, thus locking the axle. When a manual unlocking mode is selected, an open command voltage is applied forcibly to the solenoid valve 3, thus unlocking the axle. This allows an operator to make his or her own decision to ensure stabilized running even under conditions that would otherwise make running unstable if the automatic control was used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axle fixing control device for an industrial vehicle in which an axle is swingably attached to a vehicle body.

[0002]

2. Description of the Related Art Conventionally, industrial vehicles such as forklifts have adopted a technology for supporting an axle so as to be swingable with respect to a vehicle body in order to improve running performance and riding comfort. And when such an industrial vehicle turns while traveling, the centrifugal force acts and the vehicle body swings in the left and right direction, and therefore, the stability during traveling decreases and the vehicle speed cannot be increased, There has been a problem that the ride comfort is reduced due to the roll of the vehicle body and the like, and many proposals have been made to solve this problem.

For example, Japanese Patent Application Laid-Open No. 9-142120 discloses that an axle supported to be swingable with respect to a vehicle body frame is provided between the vehicle body frame and the axle, and the swing of the axle can be fixed. An axle fixing mechanism, a lateral force detecting means provided in an industrial vehicle for detecting a lateral force (lateral direction of the vehicle) acting on the vehicle, and a lateral force detected by the lateral force detecting means. Based on the magnitude of the directional force,
When the size becomes larger than the reference value, a control device for an industrial vehicle including a control means for operating the axle fixing mechanism and outputting a fixed operation signal for fixing the axle and the body frame is provided. It has been disclosed.

[0004]

However, the above-mentioned conventional industrial vehicle control device has the following problems. That is, since the axle is fixed based on the magnitude of the lateral force, even when traveling on a rough road surface, the axle may be fixed to the body frame, and the rough road surface with the axle fixed may be When the vehicle runs, the rocking of the vehicle due to the unevenness of the road surface increases, and the stability, running performance and riding comfort of the vehicle deteriorate. Therefore, there is a strong demand that the axle can be fixed or released manually at the discretion of the operator according to the road surface condition of the industrial vehicle. further,
If the control device breaks down, it will not be possible to fix and release the axle. Even if the control device breaks down, if the vehicle can be run and unloaded, it may continue to be used until a request for repair is made. In such a case, if the axle breaks down to a fixed state, the riding comfort on a rough road surface deteriorates. In such a case, it is better to release the axle fixation. In addition, when the axle breaks down to a state where it is constantly released, the stability of the vehicle during turning and during cargo handling deteriorates. Even in such a case, there is a strong demand to use the axle fixing function effectively to drive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an axle fixing control device for an industrial vehicle which enables an axle to be fixed or released when necessary by an operator. The purpose is.

[0006]

In order to achieve the above object, an invention according to claim 1 comprises an axle mounted to be vertically swingable with respect to a vehicle body; And an axle fixing device disposed between the axle and capable of locking swinging of the axle, and comparing the state value and allowable value of the cargo handling and traveling of the vehicle with each other, and locking the axle fixing device based on the comparison result. In an axle fixing control device for an industrial vehicle including a determination unit that outputs a lock command and an axle lock control unit that controls the axle fixing device in response to the lock command, automatic control of axle fixing by a lock command of the determination unit; A configuration is provided in which a function selecting means for switching between manual and forcible release is provided.

According to the first aspect of the present invention, since the function selecting means for switching between automatic control for fixing the axle and forcible release by manual operation is provided, the force is manually forced according to the condition of the road surface. Can be fixedly released. As a result, even in the case of a road surface condition that is likely to be unstable when the automatic control for fixing the axle is performed, the vehicle can be unlocked manually by the judgment of the operator and the vehicle can run stably.

According to a second aspect of the present invention, based on the first aspect of the invention, the function selecting means can be further switched to manually forcibly fixing the axle.

According to the second aspect of the present invention, when the automatic control for fixing the axle becomes impossible, the operator can forcibly fix the axle manually by judging the condition of the road surface or the like. In addition, stability during cargo handling can be ensured.

According to a third aspect of the present invention, based on the first aspect, the function selecting means is a changeover switch.

According to the third aspect of the present invention, since the function selecting means can be configured with a simple structure by the changeover switch, the control device can be manufactured at low cost.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an axle fixing control device for an industrial vehicle according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view of a forklift 50 as an industrial vehicle to which the axle fixing control device according to the present invention is applied. In the figure, a pair of left and right front wheels 55, 55 are provided at the front of a body 51 of the forklift 50, and a pair of rear wheels 56, 56 are provided at the rear. The pair of left and right front wheels 55, 55 is connected to an engine via a transmission (not shown), and is driven by the engine. A mast 52 is provided at the front end of the vehicle body 51 so as to be vertically expandable and contractible.
A fork 53 which can be moved up and down is attached. A driver's seat 58 is provided substantially at the upper center of the vehicle body 51, and a steering handle 57 is provided near the driving panel in front of the driver's seat 58. The steering handle 57 is connected to the rear wheels 56,
56 can be steered. Therefore, the rear wheel 56,
Reference numeral 56 denotes a steering wheel.

A description will be given based on the hardware configuration diagram of the first embodiment shown in FIG. A rear axle 61 extending in the width direction of the vehicle is provided at the rear lower portion of the body 51 of the forklift 50 so as to be swingable in the vehicle vertical direction about a center pin (not shown). Rear wheels 56, 56 are rotatably connected to left and right ends of the rear axle 61 in the vehicle traveling direction, respectively.
6 axles. A steering cylinder 65 is mounted between the rear wheels 56, 56 via a steering link. Further, between the vehicle body 51 and the rear axle 61, an axle fixing device 63 that supports the axle so as to be swingable and fixable with respect to the vehicle body 51 is attached. The axle fixing device 63 in the present embodiment has a hydraulic cylinder 62 and the solenoid valve 3.
1 and the rear axle 61 are rotatably mounted.
The head chamber and the bottom chamber of the hydraulic cylinder 62 communicate with each other via the solenoid valve 3, and the solenoid of the solenoid valve 3 is connected to the controller 1 via a changeover switch 14 described later.
Connected to 0.

The solenoid valve 3 comprises a four-port two-position switching valve. The head chamber and the bottom chamber of the hydraulic cylinder of the axle fixing device 63 are connected to two output ports P1 and P2 of the solenoid valve 3, respectively. Two input ports A1, A2
Are connected to each other. When a swing command from the controller 10 is input to the solenoid of the solenoid valve 3, the solenoid valve 3 is switched to the position a, and the oil passage between the head chamber and the bottom chamber is communicated between the vehicle body 51 and the rear axle 61 (axle). Buffer.
When a fixed command from the controller 10 is input to the solenoid of the solenoid valve 3, the solenoid valve 3 is switched to the position b, the oil path between the head chamber and the bottom chamber is cut off, and the connection between the vehicle body 51 and the rear axle 61 (axle) is established. Fix (lock) the gap. The solenoid valve 3 may be constituted by two 2-port 2-position switching valves.

The vehicle speed sensor 4 detects the traveling speed of the forklift and outputs a vehicle speed signal to the controller 10. The vehicle speed sensor 2 can detect the vehicle speed by, for example, detecting the number of rotations of the rotating shaft of the front wheel 55. In the present embodiment, the change in the magnetic field of the magnet rotating in synchronization with the wheel is detected by the induction current of the coil. And an electromagnetic pickup configured to output a pulse having a frequency proportional to the number of revolutions per unit time. This pulse signal is supplied to the F / V converter 12 and the A / D converter 11 of the controller 10.
, And the frequency of the pulse is converted into a vehicle speed value. Note that the vehicle speed sensor 4 is not limited to this, and may be configured by, for example, a tacho generator or the like.

The steering angle sensor 6 detects a steering angle (hereinafter, referred to as a steering angle) θ of a steering wheel (the rear wheel 56 in the present embodiment), and outputs a steering angle signal to the CPU 20 via the A / D converter 11. I do. The steering angle sensor 6 may detect a stroke of the steering cylinder 65 corresponding to the steering angle θ, or may detect a rotation angle of the steering handle 57 (see FIG. 1). In the present embodiment, the steering angle sensor 6 is configured by a potentiometer. However, it may be constituted by, for example, a pulse encoder.

The CPU 20 is an arithmetic processing unit including a computer device such as a microcomputer and a high-speed arithmetic processing unit, and has a memory 20a for storing data such as predetermined control constant data and a control table. The CPU 20 receives the above-mentioned vehicle speed value and steering angle value, performs predetermined arithmetic processing, determines whether the axle is fixed or released, and determines whether the solenoid valve driving unit 1
The lock command and the swing command are output to 3. In the present embodiment, the CPU 20 determines the lateral force as a vehicle state value based on the vehicle speed value v and the steering angle value θ. That is,
The turning radius r is calculated from the steering angle value θ, and the lateral force F is calculated by the formula “F = v · v / r” based on the turning radius r and the vehicle speed value v. As the lateral force allowable value, a predetermined value set in advance or a correction allowable value obtained by correcting the predetermined value according to a vehicle state value (for example, a lift value of a lift) is used. The determined lateral force F is compared with the lateral force allowable value to determine whether the axle is fixed or released.

The solenoid valve drive unit 13 outputs an open / close command to the operation solenoid unit of the solenoid valve 3 via a changeover switch 14 based on the input drive commands (lock command and swing command). Switch. The solenoid valve 3 is driven by the opening / closing command from the solenoid valve driving unit 13 and controls the axle fixing device 63 to control the vehicle body to a swingable state or a fixed state.

The changeover switch 14 controls whether the axle is fixed or unlocked automatically according to a command from the controller 10 (that is, an opening / closing command from the solenoid valve driving unit 13).
Alternatively, it is an example of a function selection unit that switches whether to manually operate by an operator. The common terminal 14d of the changeover switch 14 is connected to the operation solenoid unit of the solenoid valve 3, and an opening / closing command of the solenoid valve driving unit 13 is input to the first terminal 14a of the three changeover terminals. Further, a closing command voltage and an opening command voltage to the operation solenoid of the solenoid valve 3 are input to the other second terminal 14b and the third terminal 14c, respectively. It is connected to the. First to third terminals 14a
To 14c are automatic modes of the changeover switch 14,
It corresponds to manual axle fixing mode and manual fixing release mode.

Next, the operation of the above configuration will be described.
When the automatic mode of the changeover switch 14 is selected, the solenoid valve 3 is driven to open and close by a drive command from the controller 10, and the axle fixing and releasing are automatically controlled according to the state of the vehicle. Thereby, stable turning and running can be performed according to the lift value and the lateral force. When the manual axle fixing mode of the changeover switch 14 is selected, the closing command voltage is forcibly input to the solenoid valve 3 irrespective of the driving command from the controller 10, and the axle is fixed. When the manual release mode is selected, the controller 1
Regardless of the drive command from 0, the open command voltage is forcibly input to the solenoid valve 3 to release the axle fixation. Therefore, the axle fixation release can be manually performed according to the road surface condition or the cargo handling condition at the work site by the judgment of the operator. Thus, the vehicle can run stably even under running conditions that tend to be unstable under automatic control, such as when running on a rough road. Further, even when the automatic fixing control becomes ineffective due to the failure of the controller 10 of the vehicle, the control can be performed manually. Thereby, even if the controller 10 cannot be controlled, the axle can be fixed and released without fail, and the vehicle can run stably.

Next, a second embodiment will be described with reference to FIG. FIG. 3 shows a block diagram of the hardware configuration, and the same components as those in FIG. In the present embodiment, the changeover switch 14 is the controller 1
0, and can be switched by an operation lever 15 between automatic mode, manual axle fixing, and manual fixing release. A circuit ground is connected to a common terminal 14 d of the changeover switch 14, and the first to third terminals 14 a to 14 c are connected to the CPU 20 via an input interface unit (hereinafter, referred to as an input I / F unit) 16 of the controller 10. Have been. Note that the input I / F unit 16 is connected to each of the first to third terminals 1.
The contact on / off signals from 4a to 14c are converted into digital input signals of CPU 20. First to third terminals 14a
To 14c are automatic modes of the changeover switch 14,
It corresponds to manual axle fixing mode and manual fixing release mode. The drive command signal of the solenoid valve drive unit 13 is directly input to the solenoid of the solenoid valve 3.

When an automatic mode signal is input from the changeover switch 14, the CPU 20 performs automatic control for fixing the axle based on the input signal from each sensor, as in the first embodiment. When a manual axle fixing mode signal and a manual fixing release mode signal are input, the CPU 20 forcibly outputs an axle fixing command and a fixing releasing command to the solenoid valve driving unit 13 respectively.

According to the configuration of this embodiment, when the automatic mode of the changeover switch 14 is selected, the solenoid valve 3 is driven to open and close by a drive command from the controller 10, and the axle is fixed and released according to the state of the vehicle. Is automatically controlled. Thereby, stable turning and running can be performed according to the vehicle state such as the lift value and the lateral force. When the manual axle fixing mode of the changeover switch 14 is selected, the controller 10
Irrespective of the vehicle state signal from each sensor, forcibly outputs a close command to the solenoid valve 3 to fix the axle, and when the manual release mode is selected, the controller 10 outputs the vehicle state signal. Regardless, an open command is forcibly output to the solenoid valve 3 to release the fixed axle.

Therefore, according to the judgment of the operator,
It is possible to manually fix and release the axle according to the road surface condition and the cargo handling condition at the work site. Thus, the vehicle can run stably even under the running conditions under which automatic running tends to cause unstable running. Further, even when the control of automatic fixing and release of fixing becomes ineffective due to a failure of a sensor or the like, it is possible to perform manual control without falling into axle control inability. Thus, even if the automatic control by the controller 10 becomes impossible, the axle can be fixed and released manually, and the vehicle can run stably.

As described above, according to the present invention, when the axle fixing by the automatic control becomes unstable, the vehicle travels on a road surface where the ride comfort becomes poor, or when the automatic control becomes impossible due to the failure of the controller, etc. In this case, it is possible to forcibly fix or release the axle by switching to manual operation, so that even in such a case, it is possible to improve the stability and the riding comfort during traveling. In the above-described embodiment, the control algorithm in the automatic mode has been described as an example in which the determination of the axle fixing is performed using the lateral force obtained based on the vehicle speed value and the steering angle value as the vehicle state value. It is not limited to the state value, and may be another vehicle state value (for example, lateral acceleration, lateral force change rate, centrifugal force, yaw rate change rate, vehicle speed value, steering angle value, etc.). In short, when the vehicle is likely to become unstable during turning or running by automatic control of axle fixing and unlocking based on vehicle state values, or when riding comfort is poor, forcibly fix or release the axle manually. Thereby, stability and riding comfort can be improved.

[Brief description of the drawings]

FIG. 1 is a side view of a forklift as an industrial vehicle to which an axle fixing control device according to the present invention is applied.

FIG. 2 is a block diagram of a hardware configuration according to the first embodiment.

FIG. 3 is a block diagram of a hardware configuration according to a second embodiment.

[Explanation of symbols]

3 ... solenoid valve, 4 ... vehicle speed sensor, 6 ... steering angle sensor, 10 ...
Controller, 13: solenoid valve drive unit, 20: CPU, 2
0a: memory, 50: forklift, 51: body, 5
2: Mast, 53: Fork, 55: Front wheel, 56: Rear wheel, 57: Steering handle, 58: Driver's seat, 61
... Rear axle, 63 ... Axle fixing device.

Claims (3)

[Claims] An axle attached to a vehicle body so as to be swingable in a vertical direction, an axle fixing device disposed between the body and the axle and capable of locking the swinging of the axle, and loading and unloading of the vehicle. A determination unit that compares the state value of the traveling state with the allowable value and outputs a lock command for locking the axle fixing device based on the comparison result; and an axle lock control unit that receives the lock command and controls the axle fixing device. An axle fixing control device for an industrial vehicle, comprising: a function selection unit that switches between automatic control of axle fixing by a lock command of a determination unit and manual forcible release. Control device. 2. The industrial vehicle axle fixing control device according to claim 1, wherein the function selecting means is further switchable to manually forcibly fixing the axle. Axle fixed control device. 3. The axle fixing control device for an industrial vehicle according to claim 1, wherein the function selecting means is a changeover switch.