JPH0577748A - 3-wheel battery type fork lift - Google Patents

Abstract

PURPOSE:To provide a steering device which is compact and simple in construction and with which a large space for arrangement of auxiliary devices can be obtained. CONSTITUTION:In a 3-wheel battery type fork lift in which one steering wheel 73 is provided at the rear and the steering wheel is rotated by a steering device, the steering device is provided with a pinion 1 provided on a steering wheel 73, a rack 2 engaged with the pinion, and actuators (hydraulic cylinders 231 and 232) for moving the rack 2 in axial direction. By moving the rack 2 right and left, the pinion 1 is rotated to rotate the steering wheel 73 right and left through a steering shaft.

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 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 has two front wheels 7 at the front of a chassis 75.
1, 72 and one steering wheel 73 at the rear. Then, by operating the steering wheel 86,
As shown below, the steered wheels 73 are rotated in the left-right direction to turn in the desired traveling direction. In both figures, reference numeral 76 is a fork, and 77 is a battery case.

Next, a steering mechanism between the steering wheel 86 and the steered wheels 73 will be described with reference to FIGS. 4 to 6. 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. This will be described in detail below.

That is, as shown in FIG. 5 and FIG.
A sprocket wheel 97 is provided on the upper portion of 3 via a steering shaft 74. On the other hand, the cylinder tube 94 has a piston 93 therein, 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). Also, the piston rod 9
Reference numerals 1, 92 denote oil passages 910, 9 whose one end is opened to the right hydraulic chamber 941 or the left hydraulic chamber 942 of the cylinder tube 94.
Have twenty. The oil passages 910 and 920 are connected to the hydraulic hoses 81 and 82 (Fig. 4).

Below the cylinder tube 94,
As shown in FIG. 6, brackets 945 and 946 are provided. In addition, on the chassis 75, via the 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.
Between idle sprocket wheels 961, 96
The chain 95 is provided via the two. Further, as shown in FIG. 4, the oil tank 8 is connected to the hydraulic hoses 81 and 82 via a steering control valve 85.
3. A power steering pump 84 is connected.

Next, by the steering wheel 86,
When steering the steered wheels 73, the steering wheel 86 is rotated in the 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 hydraulic control hose 81 is pressurized by the operation of the steering control valve 85. 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.
Goes in.

Therefore, the pressure in the right hydraulic chamber 941 rises, 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 turns to the left, and the steered wheels 73 connected thereto turn to the left. Therefore, the battery-powered forklift 7 turns to the right. On the other hand, when the battery-powered forklift 7 is turned to the left, the reverse operation is performed.

[0008]

However, the conventional steering device 9 for a three-wheel battery-powered forklift is of the type that moves the cylinder tube 94 in the left-right direction, and therefore has the following problems. That is, the battery-powered forklift truck, as described above, has the chassis 75, 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 above conventional steering device 9
Is a type that moves the cylinder tube 94 to the left and right.
The above accessory cannot be placed. In particular, in recent years, various types of auxiliary equipment have increased in number, and it has been required to secure a space for disposing them, and it is desired that the steering device be as compact as possible.

Further, the conventional steering device 9 is designed to change 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 are used.
62, chain 95, sprocket wheel 97 are required, and the device is large. Further, the cylinder tube 94, which is a drive source, and the steering shaft 74 are separated from each other. Therefore, the mechanism of the steering device is complicated. Also, the chain 95
If looseness occurs, steering transmission 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 device includes a pinion provided on a steering shaft of a steered wheel, a rack provided on a chassis side and meshed with the pinion, and an actuator for moving the rack in an axial direction thereof. Located on a forklift. In the present invention, the actuator is a device for moving the rack in its axial direction and turning the steered wheels via the pinion. Such actuators include hydraulic cylinders, pneumatic cylinders,
There are electric step motors and the like. Further, the actuator 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 actuator 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 rotates, the steered wheels turn,
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-right direction, the rack is arranged adjacent to the pinion provided on the steering shaft. Therefore, the entire steering system is compact and does not require a large space unlike the conventional steering system. Therefore, it is possible to take a large space for arranging the auxiliary equipment.

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, the idle sprocket wheel, chain and sprocket wheel are connected between them, but in the present invention, the pinion and the rack are connected. The steering mechanism is extremely simple because it only engages. Therefore, according to the present invention, it is possible to provide a three-wheel battery-type forklift truck that has a large space for arranging auxiliary equipment, is compact, and has a steering device with a simple mechanism.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-wheel battery forklift according to an embodiment of the present invention will be described with reference to FIGS. The steering device in the three-wheel battery-powered forklift of this example is
The pinion 1 provided on the steering shaft 61 of the steering wheel 73,
It comprises 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 direction 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 on the 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 have pistons 21 mounted in hydraulic cylinders 231 and 232, respectively.
It is connected to 0,220. Pistons 210, 220
Oil seals 215 and 225 are provided 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 a mounting hole 251 for fixing to the bracket 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 in the conventional example.

Next, the function and effect will be described. In the three-wheel battery forklift of this example, the steering wheel 86 is rotated in the 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). 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 to the right.

In the steering apparatus of this embodiment, although the rack 2 moves in the left-right direction, the rack 2 is arranged adjacent to the pinion 1 provided on the steering shaft 61. Therefore, the entire steering system can be made compact and does not require a large space unlike the conventional steering system. Therefore, it is possible to take a large space for arranging auxiliary equipment.

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

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, which facilitates the maintenance of the rack. 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 a 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 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 according to 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 type forklift truck.

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

[Explanation of symbols]

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

Claims (1)

[Claims] 1. A three-wheel battery forklift having two front wheels in the front part and one steering wheel in the rear part, and a steering device connected to the steering shaft of the steering wheel, wherein the steering device is a steering wheel. A three-wheel battery-powered forklift having a pinion provided on a wheel steering shaft, a rack provided on a chassis side and meshing with the pinion, and an actuator for moving the rack in an axial direction thereof.