JPH0775988B2 - Steering device for traveling vehicle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for a traveling vehicle, and more particularly to a steering device for a traveling vehicle that operates a cylinder by operating a steering switch to steer a drive wheel. .

[Conventional technology]

A conventional steering device for a traveling vehicle is disclosed in, for example, JP-A-61
JP-A-285129 discloses that a vehicle body of a traveling vehicle is provided with two drive wheels each provided with a drive motor for traveling on an axle and two driven wheels, which are arranged diagonally to each other so as to be pivotable on a pivot axis. Both drive wheels can rotate 90 degrees at the same time by the respective rotation axis drive motors to enable forward / backward / left traverse / right traverse straight travel, and simultaneously rotate at desired angles to turn left / right. Some have made it possible to run diagonally.

However, since the steering device for the traveling vehicle has the traveling drive motor and the turning axis drive motor installed on the vehicle body, the luggage space on the upper surface of the vehicle body is occupied accordingly.
The area used as a cargo space is reduced.

Therefore, for example, in Japanese Patent Laid-Open No. 53-114134, one steering wheel, one driving wheel, and another steering wheel and one driven wheel are diagonally arranged on a vehicle body of a traveling vehicle. It is supported by a turning axis so that it can turn around, and two steering wheels can turn 90 degrees at the same time in one cylinder via a link to enable forward / backward / left traverse / right traverse straight travel. One steering wheel, one driving wheel and two driven wheels are diagonally arranged and supported so that they can be swiveled by a swivel axis, and one steered wheel is swung 90 degrees by a cylinder to move forward / backward. The one that enables straight running of left traverse and right traverse, one steering wheel, one drive wheel and two driven wheels are diagonally arranged, respectively, and are supported so that they can be turned by a turning axis. Steering wheels and two driven wheels are turned 90 degrees with three cylinders each, and go straight forward for forward / backward / left traverse / right traverse. Steering system of the traveling vehicle is disclosed that enables.

[Problems to be Solved by the Invention]

However, in the above steering device, since the drive wheels are arranged only in one corner of the vehicle body, it is difficult to drive straight unless the steering operation is always performed, and the drive wheels are not steered directly but are steered. Since the direction is gradually changed as the wheels travel after steering, when the vehicle is steered from one straight running or turning running state to another straight running or turning running state, the vehicle immediately shifts to the desired running state. Cannot be operated and requires skill in steering operation.

Therefore, according to the present invention, it is possible to easily switch between forward traveling, backward traveling, left traverse, and right traverse straight traveling, and when performing the turning steering in this straight traveling state, the steering can be performed easily without being concerned about the turning restriction. It is intended to provide a steering device.

[Means for Solving the Problems]

In order to achieve the above object, the invention according to claim 1 has two drive wheels, which are provided with a drive source for traveling on an axle, arranged diagonally on a vehicle body of a traveling vehicle, and is supported rotatably by a turning axis. In a traveling vehicle that can drive the drive wheels 90 degrees each forward and backward, left traverse, right traverse straight traveling, connect a cylinder to the turning axis of each drive wheel to move forward, backward, left traverse, right A driving direction changeover switch for instructing traverse and a steering switch for instructing left turning and right turning are provided on the driver's cab, and a plurality of limit switches are engaged with the cam plates fixed to the respective turning shafts. Turn on these limit switches
A turning state detection mechanism for detecting the turning state of the drive wheels by a combination of off signals is provided, and the operation of both cylinders and the drive wheels are controlled based on the information of the turning state detection mechanism based on the command of the traveling direction changeover switch. Forward / reverse
Either left traverse or right traverse is performed, and one of the cylinders is operated based on the information of the turning state detection mechanism based on the instruction of the steering switch to perform left turn or right turn. The invention is further characterized in that the steering angle is restricted to the left turn or the right turn, and the steering switch is switched from one of the turning traveling positions to the neutral position. In this case, the cylinder of the driving wheel that is turning is operated based on the information of the turning state detection mechanism to restore the straight traveling state before the turning traveling.

[Work]

With this configuration, the invention according to claim 1 operates the two cylinders based on the information of the turning state detection mechanism based on the command of the traveling direction changeover switch to turn the drive wheels by 90 degrees and at the same time set the drive wheels to normal. It is possible to reverse the vehicle to drive it straight, either forward / backward, left traverse, or right traverse.In addition, in any straight traveling direction, the information of the turning state detection mechanism is displayed based on the steering switch command. Based on this, either one of the cylinders can be operated to make a left turn or a right turn, and the turning angle at this time can be limited.

Further, when the steering switch is switched from the turning traveling position to the neutral position at the time of turning in a desired direction, the cylinder of the drive wheel that is turning based on the information of the turning state detection mechanism is set. It can be activated to return to the straight traveling state before turning.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

The traveling vehicle 20 has two drive wheels 22, 23 and 2 under the vehicle body 21.
The two driven wheels 24 and 25 are arranged diagonally to each other, and the hydraulic motors 26 and 27, which are drive sources for traveling provided on the wheels of the drive wheels 22 and 23, are driven to travel.

The drive wheels 22 and 23 are rotatably supported on the vehicle body 21 by the turning shafts 28 and 29, respectively, and the driven wheels 24 and 25 are rotatably supported on the vehicle body 21 by the turning shafts 30 and 31, respectively. There is.

The rod 32a of the cylinder 32 is mounted on the arm 28a of the swivel shaft 28 of the drive wheel 22, and the cylinder 32 is mounted on the arm 29a of the swivel shaft 29 of the drive wheel 23.
The rods 33a of the cylinder 33 are connected to each other, and as shown in FIG. 1, the rod 32a of the cylinder 32 and the rod 33a of the cylinder 33 are connected.
When each of the driving wheels 22 and 23 is maximally extended, the driving wheels 22 and 23 are in a straight traveling state in a forward direction (left direction in the figure) and a backward direction (right direction in the figure), and as shown in FIG. , Rod 32a of cylinder 32 and rod 3 of cylinder 33
When 3a is reduced to the minimum, respectively, the drive wheels 22 and 23 turn 90 degrees to be in a straight traveling state in the left transverse direction (downward in the figure) and the right transverse direction (upward in the figure).

The operation panel 34 of the cab above the vehicle body 21 is provided with a traveling direction changeover switch 35 having four positions of forward, backward, left traverse, and right traverse. This traveling direction changeover switch 35 has a lever at a predetermined position. When commanding forward / backward / left traverse / right traverse when it is switched to, when switching from the left / right traverse position to the forward / backward position or from the forward / backward position to the left / right traverse position by operating the traveling direction changeover switch 35. , Rods 32a, 3 of cylinders 32, 33
3a expands and contracts, and the drive wheels 22 and 23 turn 90 degrees.

Further, the operation panel 34 is provided with a steering switch 36 having three positions of neutral, right turn and left turn. This steering switch 36 is an electric lever switch, which is switched off at the lever neutral position, and is switched on when the lever is switched to the right turning position or the left turning position to instruct the right turning or the left turning. , By this command, rod 32a of cylinder 32 or rod 3 of cylinder 33
3a expands and contracts and turns either the drive wheel 22 or the drive wheel 23. Then, when the hand is released from the lever at the right turning position or the left turning position, the lever automatically returns to the neutral position and is switched off.

The hydraulic motors 26, 27 and the cylinders 32, 33 are driven by a hydraulic circuit 37 shown in FIG.
Is composed of a hydraulic motor side circuit 38 and a cylinder side circuit 39, and an electric motor 40 rotates a hydraulic motor side pump 41 and a cylinder side pump 42. The hydraulic motor side circuit 38 has a traveling direction changeover switch 35. By the command in the position of
A traveling drive source control circuit 43 for rotating the hydraulic motors 26, 27 in the forward and reverse directions is provided.

In addition, the cylinder side circuit 39 includes the rod 32a of the cylinder 32.
Solenoid type switching valve 44 for switching expansion and contraction of the cylinder and cylinder 33
A cylinder control circuit 46 having a solenoid type switching valve 45 for switching the expansion and contraction of the rod 33a is provided, and by a command at the position of the traveling direction switching switch 35 and a command at the position of the steering switch 36,
The solenoid type switching valves 44 and 45 are actuated to expand and contract the cylinders 32 and 33.

At the lever neutral position, the steering by the steering switch 36 is in a straight traveling state in any of forward, backward, left traverse, and right traverse directions, and in the case of a forward traveling state (left in FIG. 1), the lever is operated. Is switched from the neutral position to the left turning position, the rod 32a of the cylinder 32 contracts and only the drive wheel 22 turns to make a left turn, and when the lever is changed to the right turning position, the rod 33 of the cylinder 33 is rotated.
a shrinks and only the drive wheel 23 turns to make a right turn.

In the reverse running state (rightward in FIG. 1), when the lever is switched from the neutral position to the left turning position, the cylinder
The rod 33a of 33 contracts and only the drive wheel 23 turns to make a left turn, and when the lever is switched to the right turning position, the rod 32a of the cylinder 32 contracts and only the drive wheel 22 turns. Turn right.

In the case of a right lateral traveling state (upward in FIG. 2),
When the lever is switched from the neutral position to the left turning position, the rod 33a of the cylinder 33 extends and only the drive wheel 23 turns to make a left turn, and when the lever is changed to the right turning position, the rod of the cylinder 32 moves. 32a extends and only the drive wheel 22 turns to make a right turn.

In the case of the left lateral traveling state (downward in FIG. 2),
When the lever is switched from the neutral position to the left turning position, the rod 32a of the cylinder 32 extends and only the drive wheel 22 turns to make a left turn, and when the lever is changed to the right turning position, the rod of the cylinder 33 moves. 33a extends and only the drive wheel 23 turns to make a right turn.

A turning state detection mechanism 47 is provided on each of the drive wheels 22 and 23. Since the turning state detecting mechanism 47 has the same structure, the turning state detecting mechanism 47 will be described based on the turning state detecting mechanism 47 of the drive wheels 22 shown in FIGS. 6 and 7.

The turning state detection mechanism 47 includes a cam plate 48 fixed to the turning shaft 28 of the drive wheel 22 and rotating integrally with the turning shaft 28, and a straight traveling state of the drive wheel 22 engaged with the cam plate 48. The cam plate 48 is composed of a first limit switch LS1 and a second limit switch LS2 for detecting the turning traveling state, and the cam plate 48 operates the first limit switch LS1 and the second limit switch LS2 in the straight traveling state and the turning traveling state. It is an operating part that makes the situation different.

A first cam surface 48a, a second cam surface 48b, a third cam surface 48c and a fourth cam surface 48d are continuously formed on the cam plate 48.
The limit switch LS1 and the second limit switch LS2 are
It is arranged so as to face the cam surface of the cam plate 48 with a 90-degree phase shift, and detects the straight traveling state and the turning traveling state of the drive wheel 22 by the combination of the ON / OFF signals of these limit switches LS1, LS2. .

That is, the first cam surface 48a is the first limit switch from the forward / backward straight traveling state until the cam plate 48 rotates by 65 degrees.
Turn on LS1.

The second cam surface 48b is
When the second limit switch LS2 is turned off and the cam plate 48 rotates from 65 degrees to 95 degrees, the first limit switch LS1 is turned off.

The third cam surface 48c turns on the second limit switch LS2 when the cam plate 48 rotates from 5 degrees to 85 degrees.

The fourth cam surface 48d turns off the second limit switch LS2 when the cam plate 48 rotates from 85 degrees to 95 degrees.

As a result, as shown in FIGS. 8 and 9, in the forward / backward straight traveling state, the first limit switch LS1 is turned on and the second limit switch LS2 is turned off, so
In the turning traveling state in the backward traveling state, both the first limit switch LS1 and the second limit switch LS2 are turned on from the straight traveling state until the drive wheels 22 turn 65 degrees.
When the turning of the drive wheel 22 exceeds 65 degrees, only the first limit switch LS1 is turned off.

Further, in the left traverse / right traverse straight traveling state, both the first limit switch LS1 and the second limit switch LS2 are turned off, and from the straight traveling state until the drive wheel 22 turns 25 degrees,
Only the second limit switch LS2 turns on.

Therefore, when only the first limit switch LS1 is on, the drive wheels 22 are in the forward / backward straight traveling state, and when both the first limit switch LS1 and the second limit switch LS2 are on, Drive wheel 22 moves forward
It is possible to detect that the vehicle is in the turning traveling state in the backward traveling state.

When both the first limit switch LS1 and the second limit switch LS2 are off, the drive wheel 22 is in the left traverse / right traverse straight traveling state, and the second limit switch
When only LS2 is turned on, it can be detected that the drive wheels 22 are in the turning traveling state in the left traverse / right traverse traveling states.

In this embodiment, the steering limit is set to 65 degrees when the first limit switch LS1 is turned off in the forward / reverse traveling state, and to 25 degrees when the first limit switch LS1 is turned on in the left traverse / right transverse traveling state. θs is set (determined by the wheelbase and wheelbase), and the steering switch 36
In the operation of, the drive wheel 22 is restricted so as not to turn any more.

The drive wheel 23 also operates in the same manner as the drive wheel 22.

In this way, based on the command of the traveling direction changeover switch 35, based on the information of the turning state detection mechanism 47, the operation of the cylinders 32 and 33 and the driving wheels 22 and 23 are normally and reversely rotated to move forward / backward / leftward / rightward. A turning state detection mechanism 47 is operated based on a command from the steering switch 36 while the vehicle is traveling in either direction.
Based on the information of (1), either one of the cylinders 32, 33 is operated to make a left turn or a right turn, and a left or right turn angle is restricted.

When the hands of the lever of the steering switch 36 are released in the turning traveling state of the drive wheels 22 described above, the lever returns to the neutral position and is switched off, and the control means shown in FIG. 9 causes the control means shown in FIG. If the ON / OFF state of the second limit switch LS2 is detected and both the first limit switch LS1 and the second limit switch LS2 are ON, the drive wheels 22 are in the turning traveling state in the forward / reverse traveling state. The rod 32a of the cylinder 32 is maximally extended to bring the arm 28a of the turning shaft 28 into contact with the stopper 50, and the drive wheel 22 is returned to the forward / reverse straight traveling state. As a result, the drive wheels 22 are brought into the forward / backward straight traveling state, and the first
Only the limit switch LS1 turns on and the second limit switch LS2 turns off.

Further, when only the second limit switch LS2 is turned on and the first limit switch LS1 is turned off, the drive wheel 22 is in the turning traveling state in the left traverse / right traverse traveling state, so the rod 33a of the cylinder 33 is Revolving axis 28 with a minimum reduction
The arm 28a of the abutment is brought into contact with the stopper 51, and the drive wheel 22 is returned to the left traverse / right traverse straight traveling state.
Both the limit switch LS1 and the second limit switch LS2 are turned off.

The drive wheel 23 also operates in the same manner as the drive wheel 22.

As described above, when the steering switch 36 is switched from one of the turning traveling positions to the neutral position, the cylinder of the driving wheel that is turning is operated based on the information of the turning state detection mechanism 47 before the turning traveling. Return to straight running condition.

By configuring the traveling vehicle 20 as described above, the traveling direction selector switch 35 can switch forward traveling, backward traveling, left traverse, and right traverse straight traveling, and the steering switch 36.
Drive wheel 2 by switching the lever to the desired turning position.
You can maneuver forward, backward, left traverse, right traverse by turning either 2, 23, and further, when you release the lever of the steering switch 36 that has been switched to the turning position, the lever will return to the neutral position. Drive wheels 22,2
Detecting the turning situation of 3 and setting the drive wheels 22 and 23 to the changeover switch 35
It is possible to return the vehicle to the straight traveling state in the traveling direction of forward / backward / left traverse / right traverse at the position.

In this embodiment, two limit switches are used for description, but three or more limit switches may be used.

〔The invention's effect〕

As described above, in the steering apparatus of the present invention, two drive wheels each having a drive source for traveling on an axle are diagonally arranged on a vehicle body of a traveling vehicle so as to be pivotally supported by a turning axis. Cylinders are connected to the swivel axes of the
By turning 90 degrees, it is possible to go straight forward / backward / left traverse / right traverse, with a traveling direction changeover switch for commanding forward / backward / left traverse / right traverse and a steering switch for commanding left turn / right turn A slewing system that is installed on the driver's cab, engages a plurality of limit switches with cam plates fixed to each slewing axis, and detects the turning state of the drive wheels by combining the on / off signals of these limit switches. A state detection mechanism is provided, and based on the information from the turning state detection mechanism, based on the information from the turning state detection mechanism, the operation of both cylinders and the drive wheels are rotated in the forward and reverse directions to move forward, backward, left traverse, or right traverse. In addition to driving, one of the cylinders is operated based on the information from the turning state detection mechanism based on the steering switch command to turn left or right, and turn left or right. Since the turning angle is limited, the traveling direction changeover switch is operated, both cylinders are operated and both drive wheels are turned 90 degrees, thereby moving the traveling vehicle forward, backward, left traverse, right traverse. In either straight traveling direction, by switching the steering switch to the side you want to turn right or left, either one of the predetermined cylinders will operate and forward / backward / left traverse -Driving to the right side allows the drive wheels to turn to the turning limit, so you can turn with simple maneuvering without worrying about the turning limit.

Further, when the steering switch is switched from one of the turning traveling positions to the neutral position, the cylinder of the driving wheel that is turning is operated based on the information of the turning state detection mechanism, and the straight traveling state before the turning traveling is performed. Therefore, if the steering switch is set to neutral when the traveling vehicle turns in the desired direction, the cylinders of the driving wheels that are turning are operated based on the information from the turning state detection mechanism to turn the vehicle. You can return to the previous straight running condition.

Therefore, when the lever of the steering switch is set to the neutral position, the driving wheels are always directed straight, so that the operator's thinking load is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 8 show an embodiment of the present invention, and FIG. 1 is a plan view showing a traveling state of a traveling vehicle in a straight forward and backward direction,
FIG. 2 is a plan view showing a lateral traveling state, FIG. 3 is a side view, FIG. 4 is a plan view of an operation panel, FIG. 5 is a hydraulic circuit diagram of a traveling vehicle, and FIG. 8 is an enlarged plan view showing a turning state detection mechanism in FIG. 7, FIG. 7 is an enlarged plan view showing a turning state detection mechanism in a lateral straight traveling state, FIG.
FIG. 9 is an explanatory view showing the operating condition of the limit switch, and FIG. 9 is a flow chart showing the control means. 20 …… Running vehicle, 21 …… Body, 22,23 …… Drive wheel, 24,25
...... Driven wheels, 28,29 …… Drive wheel swivel axis, 32,33 …… Cylinders, 32a, 33a …… Cylinder rods, 35 …… Running direction changeover switch, 36 …… Steering switch, 37 ……
Hydraulic circuit, 43 ... Drive source control circuit for traveling, 44, 45 ... Solenoid type switching valve, 46 ... Cylinder control circuit, 47 ... Turning state detection mechanism, 48 ... Cam plate, 48a ... 1st cam Face, 4
8b ... 2nd cam surface, 48c ... 3rd cam surface, 48d ... 4th cam surface, LS1 ... 1st limit switch, LS2 ... 2nd limit switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masamasa Nakada 4-6-15 Sendagaya, Shibuya-ku, Tokyo Fujita Industry Co., Ltd. (72) Seiichi Shibayama 4-6-15 Sendagaya, Shibuya-ku, Tokyo Fujita Industry Co., Ltd. (56) Reference JP-A-61-285129 (JP, A) JP-A-53-114134 (JP, A)

Claims (2)

[Claims] 1. A vehicle body of a traveling vehicle, in which two drive wheels having a drive source for traveling on an axle are diagonally arranged and rotatably supported by a turning axis, and both drive wheels are turned by 90 degrees. In a traveling vehicle capable of forward traveling, backward traveling, left transverse traveling, and right transverse traveling, a cylinder is connected to each of the drive shafts and a traveling direction changeover switch for instructing forward traveling, backward traveling, left traveling, and right traveling. A steering switch for instructing a left turn or a right turn is provided in the driver's cab, and a plurality of limit switches are engaged with the cam plates fixedly mounted on the respective turning axes to turn on / off signals of these limit switches. Is provided with a turning state detection mechanism for detecting the turning state of the drive wheels. Based on the information from the turning state detection mechanism, the operation of both cylinders and the forward and reverse rotation of the drive wheels are reversed based on the command from the traveling direction changeover switch. Let me move forward In addition to running backward, left traverse, or right traverse, one of the cylinders is operated based on the information from the turning state detection mechanism based on the command from the steering switch to turn left or right. Let
A steering device for a traveling vehicle, characterized in that a turning angle for turning left or turning right is restricted. 2. When the steering switch is switched from one of the turning traveling positions to the neutral position, the cylinder of the driving wheel that is turning is operated based on the information of the turning state detecting mechanism before the turning traveling. The steering device for a traveling vehicle according to claim 1, wherein the steering device is returned to the straight traveling state.