JP3249105B2 - Work vehicle with traversing system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle having a traversing system capable of switching to traversing.

[0002]

2. Description of the Related Art Conventionally, working vehicles having a traversing system are found in large-sized transport vehicles, some loaders, and the like. In forklifts, they are present in reach-type electric vehicles. There is also a side forklift in which a mast or a fork is mounted laterally with respect to the movement of a vehicle and handles long objects. However, there is no counter-type forklift capable of traversing and having the same function as a side fork, in addition to ordinary work. In order to establish such a forklift, it is necessary to steer the front wheels, which are the drive wheels, so as to face right beside.

That is, the conventional forklift 1 shown in FIG. 8 is provided with a pair of left and right front wheels (drive wheels) 3 at a front portion of a vehicle body 2 and a pair of left and right rear wheels 4 at a rear portion. The driver's seat 5 at the front of the body 2
Is provided. At the front end of the vehicle body 2, a mast 6 that can expand and contract in the vertical direction is attached via a connecting shaft 7 in the vehicle width direction so as to be rotatable in the front-rear direction, and a tilt cylinder 8 that rotates back and forth is provided. It is provided between the vehicle body 2 and the mast 6.

The mast 6 comprises a pair of left and right outer frames 9 on the forklift 1 side, and a pair of left and right inner frames 10 which are guided by the outer frame 9 and can move up and down.
0 is provided with a lift cylinder 11. In addition, a lift bracket 12 that is guided by the inner frame 10 and that can move up and down is provided.
A pair of left and right forks 13 is provided via a pair of upper and lower finger bars.

[0005] The driver's seat 5 is provided with a seat 15 and a handle 16 positioned in front of the seat 15.
A head guard 19 is disposed above the head guard 19 via a front pipe 17 and a rear pipe 18 erected from the main body 2 side. Further, a counterweight 20 is provided on the main body 2 behind the seat 15.

[0006]

In the conventional forklift 1 described above, since the left and right front wheels 3 are driven by a common traveling drive device, it is not possible to steer the front wheels 3 so as to face right beside. No, so traversing is not possible.

Therefore, the invention according to claim 1 of the present invention can steer the drive-type front wheel so as to be directed to the side, and furthermore, at the time of traversing, assist in straight-ahead traveling and change the direction of the vehicle body (vehicle). It is an object of the present invention to provide a work vehicle having a traversing system capable of controlling a posture at a constant speed.

[0008]

According to a first aspect of the present invention, there is provided a working vehicle having a traversing system, wherein a front wheel and a rear wheel are provided on a vehicle body so as to be capable of turning. The front wheels are a pair of left and right wheels, each of which is interlockingly connected to a drive shaft on the traveling drive device side, and both traveling drive devices are attached to a turning member provided rotatably around a vertical axis with respect to the vehicle body side. In addition, a turning means for turning the turning member is provided, and the turning means is configured to turn both the turning members in opposite directions by a hydraulic operating device, and includes a hydraulic pump and a work control valve. A switching valve means is provided in the piping with the valve, and the piping switched by the switching valve means is connected to a control valve for a hydraulic actuator via a flow divider. It is obtained by the.

Therefore, according to the first aspect of the present invention, the switching valve means is in the one-way switching state during normal traveling, and the entire flow rate of the pressure oil from the hydraulic pump flows to the working control valve. Then, the hydraulic operating device directs the left and right front wheels in the front-rear direction at the neutral position. Such a working vehicle can travel back and forth and can operate various working parts via working control valves.

When switching from normal traveling to traversing traveling, the switching valve means is set to the other switching state. Thus, the entire flow rate of the pressure oil from the hydraulic pump is sent to the flow divider, and the flow rate is controlled by the flow divider, so that a constant flow rate of the pressure oil can flow to the control valve for the hydraulic actuator. That is, by the flow divider,
A fixed amount of pressure oil can flow through the control valve for the hydraulic actuator regardless of the flow rate of the pressure oil from the hydraulic pump.

In this control valve for a hydraulic operating device, only the hydraulic oil required for turning is controlled to flow to the hydraulic operating device, whereby the hydraulic operating device is operated to one side, and the two turning members are moved around the longitudinal axis. To turn the two front wheels 90 degrees relative to the vehicle body (directly to the side). Here, since both front wheels are respectively integrated with the traveling drive device, the 90-degree turning can be easily and smoothly performed. After the front wheels have been turned right and left in this manner, the traveling vehicle can be controlled to rotate the front wheels in opposite directions so that the work vehicle can travel laterally in the left and right directions. At that time, the rear wheel is forcibly changed in the following direction by a turning caster type or in the same manner as the front wheel.

When performing such traversing, that is, in a traversing mode in which both front wheels are turned at 90 degrees with respect to the vehicle body, the hydraulic operating device is slightly operated to move both front wheels inward or forward. By turning outwards to a small angle (range of about 5 degrees), the road surface condition and weight balance (load fluctuation before and after)
It is possible to easily correct the deviation of the straightness coming from. By turning (moving) both front wheels in and out, it is also possible to slightly change the direction of the work vehicle during traversing,
In addition, the vehicle can be turned during traversing.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. In the embodiment, the same components or almost the same components as those in the above-described conventional example (FIG. 8) are denoted by the same reference numerals, and the details are omitted. That is, 1 is a forklift which is an example of a work vehicle, 2 is a vehicle body, 3 is a front wheel, 4 is a rear wheel, 5 is a driver's seat, 6 is a mast, 7 is a connecting shaft, 8 is a tilt cylinder, 9 is an outer frame, 10 is an inner frame, 11 is a lift cylinder,
12 is a lift bracket, 13 is a fork, 15 is a seat, 16 is a handle, 17 is a front pipe, 18 is a rear pipe, 19 is a head guard, and 20 is a counterweight.

A pair of left and right front wheels 3 and a pair of right and left rear wheels 4
Are provided so as to be able to turn 90 degrees with respect to the vehicle body 2 (turning right beside). That is, the pair of left and right front wheels 3 has their rims 3A connected to the rotating flanges (drive shafts) 22 of hydraulic motors (traveling driving devices) 21 by connecting members 23, respectively.
, So that it is linked to the motor 21 side.

The mount of the motor 21 is mounted horizontally on the vertical plate portion of the inverted L-shaped turning member 24, and the horizontal plate portion of the turning member 24 is mounted on the bearing 25.
And a vertical axis 26, and is provided rotatably about a vertical axis 27 with respect to the vehicle body 2 side. At that time, the vertical axis 27
Is configured to be located directly above the front wheel 3.

A turning means 30 for turning the turning member 24 is provided. The turning means 30 is configured to turn both the turning members 24 in opposite directions by a common hydraulic operating device. ing. That is, the two turning members 24
Are provided with vertical pins 31 respectively. At this time, both vertical pins 31 are located in opposite directions in the front-rear direction with respect to the longitudinal axis 27.

A link member 32 in the vehicle width direction is provided, and both ends of the link member 32 are connected to the vertical pin 31 so as to be relatively rotatable. A turning cylinder that moves the link body 32 in the vehicle width direction (an example of a hydraulic actuator)
Reference numeral 33 is disposed in the vehicle width direction, and its cylinder main body is connected to one side of the main body 2 so as to be relatively rotatable, and the piston rod is relatively rotated by a bracket 34 connected from the turning member 24 on the other side. They are freely connected. Above 3
An example of the rotating means 30 is constituted by 1 to 34 and the like.

The rims 4A of the pair of left and right rear wheels 4 are respectively attached to the vertical plate portions of the revolving member 35 so as to freely rotate, and the horizontal plate portions of the revolving member 35 are connected via bearings 36 and longitudinal axes 37. And the longitudinal axis 3
8 is provided so as to be rotatable. In this case, the longitudinal axis 38 is configured to be located directly above the rear wheel 4. In other words, the pair of left and right rear wheels 4 are configured to follow in a turning caster type.

An engine 40 is provided on the vehicle body 2 side, and a pair of pumps 41 and a hydraulic pump 50 driven by the engine 40 are provided. Then, the corresponding pump 41 and the hydraulic motor 21 are connected to a pipe (so that the pump 41 corresponds to one hydraulic motor 21, ie, a two-pump two-motor type hydraulic drive system (HST system)). (A hydraulic hose or the like) 42.

The hydraulic pump 50 is connected to a work control valve 51 for controlling the tilt cylinder 8 and the lift cylinder 11 via a pipe 52. A solenoid valve (an example of a switching valve means) 53 is provided in the pipe 52, and a pipe 54 on the side switched by the solenoid valve 53 is connected to a control valve 5 for a hydraulic operating device via a flow divider 55.
6 is connected.

The return pipe 57 through which the excess flow in the flow divider 55 flows is connected to the working control valve 5.
1 and a return valve 57 is interposed with a check valve 58. Reference numeral 59 denotes a tank.

The operation of the above embodiment will be described below. 1, 3 and 4 and FIG. 5 show a normal running state. At this time, the solenoid valve 5
Reference numeral 3 denotes an off state, and the entire flow rate of the pressure oil from the hydraulic pump 50 is flowing to the working control valve 51 via the pipe 52. The turning cylinder 33 is set at the center position, and the left and right front wheels 3 and the left and right rear wheels 4 are oriented in the front-rear direction by moving the link body 32 to the center. Such a forklift 1 has a seat 1 of a driver's seat 5.
The worker sitting at 5 can move by operating the handle 16.

By operating the lift lever and operating the lift cylinder 11 via the work control valve 51, the fork 13 can be moved up and down along the mast 6 via the lift bracket 12 and the like. To perform the intended fork work. By operating the tilt lever and operating the tilt cylinder 8 via the work control valve 51, the mast 6 can be rotated (tilted) around the connection shaft 7, and thus the mast 6 can be rotated via the lift bracket 12 or the like. Thus, the attitude of the fork 13 can be changed.

When switching from such normal running to traversing running, first, a lever type traversing mode switch (not shown) is operated to input a signal to the solenoid valve 53, and as shown in FIG. Switch to the ON state. As a result, the total flow rate of the pressure oil from the hydraulic pump 50 is
Via the flow divider 55. The flow rate of the pressure oil is controlled by the flow divider 55, so that a constant flow rate of the pressure oil flows to the control valve 56 for the hydraulic actuator via the pipe 54. Note that the flow divider 55
The surplus flow rate other than the oil whose flow rate is controlled by the above flows through the return pipe 57 to the working control valve 51.

The control valve 5 for the hydraulic operating device
At 6, only the pressure oil necessary for turning is controlled by the control lever and flows to the turning cylinder 33. This allows
For example, when the turning cylinder 33 is contracted,
With the movement of 2, the turning member 24 is turned around the longitudinal axis 27. At this time, since the link body 32 is positioned in a cross shape with respect to the left and right front wheels 3, as shown in phantom lines in FIGS. 2, 3 and 4, and in FIG. After being turned around the vertical axis 27 in opposite directions, the two front wheels 3 are turned 90 degrees (directly sideways) with respect to the vehicle body 2.

Here, the front wheels 3 are
Since it is integrated with the front wheel 3, the 90-degree turning can be easily and smoothly performed. Further, since the longitudinal axis 27 is located right above the front wheel 3, the front wheel 3 and the like can be made compact. Thus, a 90-degree turning can be performed.

The sensor detects that the front wheel 3 has been turned in this way, that is, that the front wheel 3 has been turned right and left, and turns on the indicator lamp, thereby enabling the traversing mode. Become. Therefore, engine 4
By supplying the hydraulic pressure from a pair of pumps 41 driven by the front wheel 3 to the corresponding hydraulic motor 21 through a pipe 42 by forward / reverse control in the driver's seat 5, the front wheels 3
Can be driven in the opposite direction, so that the forklift 1 can be traversed right and left.

At this time, the hydraulic motors 21 corresponding to the left and right front wheels 3 are controlled so that their rotation directions are reversed. The pair of left and right rear wheels 4 in the form of a turning caster follow and turn around a vertical axis 38.

When performing such traversing, that is, in a traversing mode in which both front wheels 3 are turned 90 degrees (directly to the side) with respect to the vehicle body 2, the turning cylinder 3 is turned.
7 is slightly extended, and as shown in FIG. 7 (a), the front wheels 3 are turned inward (C-shape) at a small angle (range of about 5 degrees).
7 and the turning cylinder 33 is slightly contracted, and as shown in FIG. 7 (b), the front wheels 3 are turned outward (inverted C-shape) to a small angle (about 5 degrees). Or range). This makes it possible to easily correct a deviation in straightness due to road surface conditions and weight balance (load fluctuations before and after) in traversing travel.

By turning (moving) the front wheels 3 inward and outward at a small angle (in the range of about 5 degrees), it is possible to slightly change the direction of the forklift 1 during traversing. In addition, if possible, the turning angle of the front wheels 3 can be increased to 5 degrees or more to enable the vehicle to make a turn during traversing.

As described above, the flow divider 55 allows a certain amount of pressure oil to flow to the hydraulic operating device control valve 56 regardless of the engine speed.
Posture control when turning or traversing the front wheel 3 (straightness correction)
Can be easily and smoothly performed at a constant speed. For example, when the vehicle travels sideways at a very low speed, the amount of depression of the accelerator pedal is small and the engine speed is low, but the attitude can be controlled sufficiently. Even if the engine speed is increased to the maximum, there is no sudden turning.

As described above, the traversing can be performed, so that a long object can be easily transported through the fork 13, for example. In addition, since the two-pump two-motor type hydraulic drive system is adopted as the drive type of the forklift 1, the above-described turning during the normal traveling is performed as follows.
The rotation direction and the rotation speed difference of the front wheels 3 are determined by a handle wheel. When the vehicle travels in a transverse direction, the turning system is electrically stopped.

In the above-described embodiment, the hydraulic cylinder 33 for the left and right sides is used as the hydraulic actuator 33 of the rotating means 30.
Although 3 is shown, it may be of the left and right separate type.

In the above-described embodiment, the solenoid valve 53 is shown as the switching valve means, but it may be a valve mechanically switched by a lever.

In the above-described embodiment, the counter type forklift 1 is shown as a work vehicle. However, a work vehicle such as a large-sized transport vehicle, a loader, a side forklift, or the like can similarly function. It is.

In the above-described embodiment, a pair of right and left rear wheels 4 is of a swivel caster type that is adapted to follow. However, similarly to the front wheels 3, the rear wheels 4 are forcibly changed by a cylinder or the like. Oriented format may be adopted.
Also, of the pair of left and right rear wheels 4, one of the rear wheels 4 may be of a steering wheel type and the other of the rear wheels 4 may be of a turning caster type. Is forcibly turned by a cylinder or the like.

In the above-described embodiment, a pair of right and left rear wheels 4 is shown, but this is a form in which left and right paired rear wheels 4 are arranged at a central portion of the vehicle width. There may be.

[0038]

According to the first aspect of the present invention, the switching valve means is in the one-way switching state during normal running, so that the entire flow rate of the hydraulic oil from the hydraulic pump can flow to the working control valve. Then, the hydraulic operating device directs the left and right front wheels in the front-rear direction at the neutral position. Such a working vehicle can move back and forth and can operate various working parts via working control valves.

When switching from normal traveling to traversing traveling, by setting the switching valve means to the other switching state, the entire flow rate of the pressure oil from the hydraulic pump is sent to the flow divider, and the flow rate is controlled by the flow divider.
A constant flow of pressure oil can flow to the control valve for the hydraulic actuator.

In this control valve for a hydraulic operating device, only the hydraulic oil required for turning is controlled and flowed to the hydraulic operating device, whereby the hydraulic operating device is operated to one side, and the two turning members are moved around the longitudinal axis. , And both front wheels can be turned 90 degrees relative to the vehicle body (directly turned sideways). Here, since both front wheels are respectively integrated with the traveling drive device, the 90-degree turning can be easily and smoothly performed. After turning both front wheels in a sideways manner in this way, the working vehicle can be traversed right and left by controlling and rotating the front wheels in opposite directions by a traveling drive device. The turning direction can be changed by following the turning direction of the caster or forcedly changed in the same manner as the front wheels.

Further, when the vehicle travels in a transverse direction, that is, in a transverse mode in which both front wheels are turned at 90 degrees to the vehicle body, the hydraulic operating device is slightly operated to move the front wheels inward or outward. By changing the angle to a small angle, it is possible to easily correct the deviation of the straightness due to the road surface condition and the weight balance (load fluctuation before and after). By turning both front wheels inward and outward, it is possible to slightly change the direction of the work vehicle at the time of traversing or to turn at the time of traversing.

As described above, the flow divider allows a fixed amount of pressure oil to flow through the control valve for the hydraulic operating device regardless of the flow rate of hydraulic oil from the hydraulic pump. Posture control (straightness correction) can be easily and smoothly performed at a constant speed.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention, and is a system explanatory diagram of a work vehicle having a traversing system during normal traveling.

FIG. 2 is a system explanatory diagram of a work vehicle having the traversing system when the vehicle traverses.

FIG. 3 is a side view of a work vehicle having the traversing system.

FIG. 4 is a partially cutaway rear view of a front wheel portion of the work vehicle having the traversing system.

FIG. 5 is a schematic plan view of the work vehicle having the traversing system during normal traveling.

FIG. 6 is a schematic plan view of the work vehicle having the traversing system during traversing.

FIG. 7 is a schematic plan view of a work vehicle having the traversing system at the time of traversing traveling adjustment.

FIG. 8 is a side view of a forklift, showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Forklift (work vehicle) 2 Body 3 Front wheel 4 Rear wheel 5 Driver's seat 8 Tilt cylinder 11 Lift cylinder 13 Fork 16 Handle 21 Hydraulic motor (traveling drive device) 22 Rotating flange (drive shaft) 24 Revolving member 27 Vertical axis 30 Rotating means 32 Link body 33 Rotating cylinder (hydraulic operating device) 35 Revolving member 38 Vertical axis 40 Engine 41 Pump 50 Hydraulic pump 51 Working control valve 52 Piping 53 Solenoid valve (switching valve means) 54 Piping 55 Flow divider 56 Control valve for hydraulic actuator 57 Return piping

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B66F 9/075 B62D 7/14

Claims (1)

(57) [Claims] 1. A front wheel and a rear wheel are respectively provided on a vehicle body so as to be able to turn. A pair of left and right front wheels are respectively connected to a driving shaft on a traveling driving device side, and both traveling driving devices are connected to the vehicle body side. On the other hand, there is provided a turning means attached to a turning member rotatably provided around the longitudinal axis and for turning the turning member, and the turning means is provided by a hydraulic operating device. Are switched in opposite directions, switching valve means is provided in the piping between the hydraulic pump and the working control valve, and the piping switched by the switching valve means is connected to the hydraulic pressure through the flow divider. A work vehicle having a traversing system connected to a control valve for an actuator.