JP2689784B2 - Three-wheel battery-powered forklift - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-wheel battery type forklift having one rear wheel as a steering wheel, and more particularly to a mechanism of a steering device for the steering wheel.

[0002]

2. Description of the Related Art As shown in FIGS. 7 and 8, a three-wheel battery-powered forklift 7 includes two front wheels 7 at the front of a chassis 75.
1 and 72, and one steering wheel 73 at the rear. Then, by operating the steering wheel 86,
As shown below, the steering wheel 73 is rotated left and right to turn in a desired traveling direction. In both figures, reference numeral 76 denotes a fork, and 77 denotes a battery case.

Next, the steering mechanism between the steering wheel 86 and the steered wheels 73 will be described with reference to FIGS. First, as shown in FIG. 4, a cylinder tube 94 is connected to a sprocket wheel 97 provided above the steered wheels 73 via a chain 95. A steering control valve 85 is connected to the cylinder tube 94 via hydraulic hoses 81 and 82. Then, by operating the steering wheel 86,
The cylinder tube 94 is moved left and right by hydraulic pressure, and the steered wheels 73 are steered via the chain 95 and the sprocket wheel 97. Hereinafter, this will be described in detail.

That is, as shown in FIG. 5 and FIG.
A sprocket wheel 97 is provided on the upper part of the wheel 3 via a steering shaft 74. On the other hand, the cylinder tube 94 has a piston 93 inside, and piston rods 91 and 92 are connected to both sides of the piston 93. The base ends 911 and 921 of the piston rods 91 and 92 are fixed to the chassis 75 (FIGS. 4 and 6). In addition, the piston rod 9
Oil passages 910, 9 open at one end into the right hydraulic chamber 941 or the left hydraulic chamber 942 of the cylinder tube 94.
20. The oil passages 910 and 920 are connected to the hydraulic hoses 81 and 82 (Fig. 4).

On the lower side of the cylinder tube 94,
As shown in FIG. 6, brackets 945 and 946 are provided. Further, the chassis 75 is connected to the chassis 75 via shaft pins 96, 96.
Idle sprocket wheels 961 and 962 are provided. Then, the sprocket wheel 97 and the left and right brackets 945, 946 of the cylinder tube 94.
The idle sprocket wheels 961 and 96
2, a chain 95 is interposed. Further, as shown in FIG. 4, the oil tank 8 is connected to the hydraulic hoses 81 and 82 through a steering control valve 85.
3. The power steering pump 84 is connected.

Next, by the steering wheel 86,
In steering the steered wheels 73, the steering wheel 86 is turned in a desired traveling direction to the right or left. Here, in the case of advancing the battery type forklift to the right, when the steering wheel 86 is turned to the right, the operation of the steering control valve 85 pressurizes the hydraulic hose 81 side. for that reason,
As shown in FIG. 6, pressure oil 80 flows from the oil passage 910 of the piston rod 91 to the right hydraulic chamber 941 of the cylinder tube 94.
Enters.

As a result, the pressure in the right hydraulic chamber 941 increases, and the cylinder tube 94 moves rightward along the fixed piston rods 91 and 92. Then, the chain 95 is pulled rightward via the idle sprocket wheel 961. As a result, the sprocket wheel 97 rotates to the left, and the steered wheels 73 connected thereto rotate to the left. Therefore, the battery-powered forklift 7 turns rightward. On the other hand, when turning the battery-powered forklift 7 to the left, the reverse operation is performed.

[0008]

However, the conventional steering device 9 for a three-wheel battery type forklift has the following problems since it is of the type in which the cylinder tube 94 is moved in the left-right direction. That is, as described above, the battery type forklift has the battery case 77,
Various accessories such as the oil tank 83, the power steering pump 84, and a motor 843 for operating the pump must be mounted. However, the conventional steering device 9
Is a type in which the cylinder tube 94 is moved right and left.
The accessory cannot be placed. In particular, in recent years, various types of accessory devices have been increasing, and it is required to obtain a space for arranging them, and it is required that the steering device be as compact as possible.

Further, the conventional steering device 9 changes the linear motion of the cylinder tube 94 into the rotational motion of the steering shaft 74, so that the idle sprocket wheels 961, 9
62, a chain 95, and a sprocket wheel 97 are required, and the device is large. Further, the distance between the cylinder tube 94 as the driving source and the steering shaft 74 is apart. Therefore, the mechanism of the steering device is complicated. In addition, chain 95
When the steering is loosened, the transmission of steering becomes slow and inaccurate. In view of the above conventional problems, the present invention aims to provide a three-wheel battery-powered forklift truck that has a large space for arranging accessories, has a compact steering mechanism, and has a simple mechanism.

[0010]

According to the present invention, there is provided a three-wheel battery type forklift having two front wheels at a front portion and one steering wheel at a rear portion, and a steering device is connected to a steering shaft of the steering wheels. The steering system includes a fulcrum shaft provided above the steering shaft of the steered wheels, and a pinion coaxially fixed to the fulcrum shaft.
A rack provided on the chassis side and meshing with the pinion, and a pair of hydraulic cylinders for moving the rack in its axial direction.
The left and right ends of the rack have the hydraulic cylinders.
A three-wheel battery-powered forklift is characterized in that it is connected to the non-pressure receiving surface of the piston of the vehicle . In the present invention, the hydraulic cylinder is a device for moving the rack in its axial direction and turning the steered wheels via the pinion. That is, the left and right ends of the rack are
It is connected to the non-pressure receiving surface of the Linda piston,
It is possible to respond by operating hydraulic pressure in the hydraulic cylinder.
One piston moves and the rack moves to the right or left.
Move. Further, the hydraulic cylinder is configured to operate in conjunction with the operation of the steering wheel (see the embodiment).

[0011]

In the three-wheel battery type forklift of the present invention, when the steering wheel is rotated in accordance with the traveling direction desired by the operator, the hydraulic cylinder operates in conjunction with the rotation operation of the steering wheel. Therefore, the rack moves left and right in the axial direction, and the pinion meshed with the rack rotates. Therefore, the steering shaft connected to the pinion turns, the steered wheels turn, and the battery-powered forklift travels in the desired right or left direction.

In the steering apparatus of the present invention, although the rack moves in the left and right directions, the rack is the steering shaft.
Coaxially pairs fixed pinion fulcrum shaft provided on the top of
They are meshed with each other and arranged adjacent to each other. Therefore, the entire steering device is compact and does not require a large space unlike the conventional steering device. Therefore, the battery case
S, oil tank, power steering pump, pump
It is possible to take up a large space for the installation of auxiliary equipment such as a motor for operating the pump .

Further, conventionally, in order to change the linear motion of the cylinder tube which is the drive source into the rotary motion of the steering shaft via the rack and the pinion, the idle sprocket wheel, the chain and the sprocket wheel are connected between them. In the present invention, since the pinion and the rack are only meshed with each other, the steering mechanism is extremely simple. Ma
Also, the rack is connected to the non-pressure receiving surface of the hydraulic cylinder.
Therefore, the pressure receiving surface of the piston is narrowed by the connection with the rack.
Never be. Therefore, the piston inserted in the hydraulic cylinder is
Ston has a wide pressure receiving surface, and the same cylinder diameter
To obtain a large propulsion force, and to reduce the size of the hydraulic cylinder.
Can be. Therefore, according to the present invention, it is possible to take a large space for arranging the accessory device, and it is compact and
Further, it is possible to provide a three-wheel battery type forklift truck having a steering device with a simple mechanism.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-wheel battery type forklift according to an embodiment of the present invention will be described with reference to FIGS. The steering device in the three-wheel battery type forklift of this example is
A pinion 1 provided on the steering shaft 61 of the steering wheel 73;
A rack 2 provided on a bracket 770 of the chassis and meshing with the pinion 1, and hydraulic cylinders 231 and 232 as actuators for moving the rack 2 in the axial direction (left and right of the chassis). As shown in FIG. 3, the steering shaft 61 rotatably supports a steered wheel 73 on an axle 62 below the steering shaft 61. Further, the steering shaft 61 has a fulcrum shaft 63 at an upper part thereof, and the pinion 1 is coaxially fixed to the fulcrum shaft 63. Also, the fulcrum shaft 63
Is rotatably supported by a support beam 77 provided on the chassis via a bearing 65.

On the other hand, the rack 2 has a tooth portion 20 which meshes with the tooth portion 10 of the pinion 1 as shown in FIGS. Further, both ends 21 and 22 of the rack 2 are connected to pistons 21 mounted in hydraulic cylinders 231 and 232, respectively.
0,220. Pistons 210, 220
Oil seals 215 and 225 are interposed between the hydraulic cylinders 231 and 232. Further, hydraulic hoses 81 and 82 are connected to the hydraulic cylinders 231 and 232. The hydraulic cylinders 231 and 232 are fixed to the frames 25 and 25, respectively.

Both frames 25 have mounting holes 251 for fixing to the brackets 770 of the chassis. Also,
As shown in FIG. 4, the hydraulic hoses 81 and 82 are connected to a steering control valve 85 that interlocks with a steering wheel 86. Others are the same as the conventional example.

Next, the function and effect will be described. In the three-wheel battery type forklift of this embodiment, the steering wheel 86 is rotated in a desired traveling direction.
Here, as an example of the case of traveling to the right, when the steering wheel 86 is rotated to the right, pressure oil flows to the hydraulic hose 82 via the steering control valve 85 as in the conventional example (FIG. 4). reference). And
As shown in FIGS. 1 and 2, the pressure oil 80 flows into the left hydraulic cylinder 232 and pushes the piston 220.

Therefore, the rack 2 is pushed rightward.
At this time, the piston 210 on the right side of the rack 2 returns the pressure oil 80 in the hydraulic cylinder 231 to the oil tank via the hydraulic hose 81 and the steering control valve (see FIG. 4). Then, as the rack 2 moves to the right, the pinion 1 meshing with the rack 2 rotates to the left. Therefore, as shown in FIGS. 1 and 3, the steering shaft 61 fixed to the pinion 1 rotates in the same direction, and the steered wheels 61 turn left. Therefore, the battery-powered forklift moves rightward.

In the steering apparatus of this embodiment, the rack 2 moves in the left-right direction, but the rack 2 is arranged adjacent to the pinion 1 provided on the steering shaft 61. Therefore, the entire steering device can be made compact, and a large space is not required unlike the conventional steering device. Therefore, it is possible to increase the arrangement space for the accessory.

Further, since the rack 2 which is the drive source only engages with the pinion, the steering mechanism is extremely simple. In this regard, in the conventional device, the linear motion of the cylinder tube is changed to the rotational motion of the steering shaft, and the interval is connected by an idle sprocket wheel, a chain, and a sprocket wheel, so that the steering mechanism becomes large and complicated. In this example, the hydraulic cylinder 23
1, 232 are attached to the chassis bracket 770 via the frames 25, 25. And each frame 25
Is provided with a mounting hole 251 for inserting a bolt.

Therefore, the engagement between the rack 2 mounted on the hydraulic cylinders 231 and 232 and the pinion 1 can be easily adjusted. That is, the backlash between the rack and the pinion can be adjusted, and the steering response is improved. Further, the hydraulic cylinders 231 and 232 can be removed, and the maintenance of the rack becomes easy. Further, in the conventional cylinder tube, the piston is inserted inside and the piston rods are provided on both sides of the piston, so the pressure receiving area that the piston receives from the hydraulic pressure is small by the area of the diameter of the piston rod.
Therefore, it was necessary to enlarge the shape of the sprocket wheel. However, in this example, the hydraulic cylinders 231 and 23
Since the pistons 210 and 220 inserted into the second cylinder have the entire diameter as the pressure receiving area, a large propulsive force can be obtained with the same cylinder diameter, and the pinion diameter may be smaller than the sprocket wheel diameter.

[Brief description of the drawings]

FIG. 1 is a plan view of a steering device in a three-wheel battery type forklift according to an embodiment.

FIG. 2 is an enlarged plan view of a main part of the steering device in the embodiment.

FIG. 3 is a side view of a steering device and steered wheels in the embodiment.

FIG. 4 is an overall explanatory view of a steering device in a conventional example.

FIG. 5 is a conceptual side view of a steering device in a conventional example.

FIG. 6 is a rear side explanatory view of a steering device in a conventional example.

FIG. 7 is a plan view of a conventional three-wheel battery-powered forklift.

FIG. 8 is a side view of a conventional three-wheel battery type forklift truck.

[Explanation of symbols]

 1. . . Pinion, 2. . . Rack, 210, 220. . . Piston, 231,232. . . Hydraulic cylinder, 61. . . Steering axis, 73. . . Steering wheel, 81, 82. . . Hydraulic hose, 85. . . Steering control valve, 86. . . Steering wheel,

Claims (1)

(57) [Claims] 1. A three-wheel battery type forklift having two front wheels in the front part and one steering wheel in the rear part, wherein a steering device is connected to a steering shaft of the steering wheel, wherein the steering device is a steering wheel. A fulcrum shaft provided above the wheel steering shaft, a pinion coaxially fixed to the fulcrum shaft, a rack provided on the chassis side and meshing with the pinion, and a pair of hydraulic pressures for moving the rack in the axial direction. Has a cylinder and
Ri, left and right end portions of the rack, of the hydraulic cylinder piston
A three-wheel battery-powered forklift that is connected to the pressure-free surface of the engine.