JPH08216898A - Steering mechanism of fork-lift truck - Google Patents

Abstract

PURPOSE: To minimize a space for setting up a transmission device and a steering driver or the like in the lower part of a battery by installing a manual torque transfer mechanism of a fork-lift truck in the lowermost part of a car body, and setting up an electric torque transfer mechanism in a rear axle. CONSTITUTION: When a driver of a fork-lift truck A rotates a steering wheel 1, torque of a steering wheel shaft 2 changes its rotational direction at a first joint 3 and it is transmitted to a first sprocket wheel 4, and then transmitted to a second sprocket wheel 6 via a chain 5. In addition, the torque transmitted to a shaft of a steering torque detector 7 changes its rotational direction at a second joint 8, and it is transmitted to a first bevel gear 9A and a second bevel gear 9b, and further transmitted to the rear of a car body via a third joint 10. The torque transmitted to an input shaft 11 of a steering driver in addition is transmitted to a pinion 12, and another torque from the steering wheel 1 is outputted to a rack 13. Subsequently an actuator 15 shifts this rack 13 according to the extent of steering detecting torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering mechanism for a forklift of a type in which a battery space is expanded to almost the bottom of a vehicle body.

[0002]

2. Description of the Related Art Conventionally, in the electric power steering mechanism of a forklift, the rotation of the steering wheel is converted into the swing of the pitman arm by the steering gear box, and the swing of the pitman arm moves a drag ring that penetrates the lower part of the battery back and forth. Through the manual mechanism that is transmitted to the bell crank of the rear steering mechanism via the actuator, and the front-back expansion and contraction of the rod that is the output of the actuator composed of the motor, speed reducer, and ball screw, is transmitted to the bell crank almost in parallel with the drag ring. The structure is composed of a power mechanism part.

The actuator of the steering drive is an electric cylinder composed of a motor, a speed reducer and a ball screw as described above, which is attached to a frame below the battery substantially parallel to the front-rear direction of the vehicle body. The tip of the rod is connected to the bell crank of the steering mechanism at the rear of the vehicle body. The ball screw rod expands and contracts back and forth in accordance with the rotation of the motor to swing the bell crank, and this swing swings the steering wheel via the tie rod and the knuckle arm.

[0004]

In order to meet the demands for higher performance and longer time, recent forklift trucks are of a type in which the battery space is expanded to almost the bottom of the vehicle body in order to increase the capacity of the battery. There is a forklift, and in such a vehicle, the space for arranging the transmission device and the steering drive device associated with the electric power steering in the lower part of the battery becomes very small. It was difficult.

[0005]

According to the present invention, a vehicle body, a battery mounted in the center of the vehicle body and reaching near the bottom of the vehicle body, two front wheels arranged on and driven by the vehicle body in front of the battery, and a battery Has two rear wheels which are arranged on the vehicle body and are turned behind, and which rotates a steering wheel in front of the driver seat disposed on the upper surface of the battery, and detects the driving force transmitted through the transmission device and the steering torque of the steering wheel. In a forklift that combines a driving force of a torque detector, a steering driving tool including a motor, and a speed reducer and turns the rear wheel, the transmission device includes a handle shaft rotated by a handle via a first joint. Steering torque fixed to the first sprocket wheel connected and the frame near the front of the battery below the driver's floor. A second sprocket wheel integrated with the input shaft of the output device, a chain connecting the two sprocket wheels, a first bevel gear connected to the output shaft of the steering torque detector via a second joint, and the first A manual torque transmission mechanism consisting of a second bevel gear that meshes with the second bevel gear and a third joint that transmits the rotation of the second bevel gear horizontally to the input shaft of the steering mechanism at the rear of the vehicle body at the bottom of the battery,

Further, the steering driving tool includes a cylinder supporting a rack on a bucket-shaped rear axle frame composed of a substantially rhombic bottom member and a rib member surrounding the member so that the rack can be swung left and right, and a motor for the cylinder. A rack-and-pinion type steering mechanism is characterized in that an actuator is integrally fixed to a drive mechanism including a drive mechanism and a speed reducer. The rack also serves as a relay rod of the steering mechanism, and tie rods are swingably connected to both left and right ends of the rack, and the steering wheel is swung by the swing of the rack left and right through the tie rod and the knuckle arm. The rack meshes with a counter gear driven by an output pinion from the speed reducer and swings left and right as the counter gear rotates. Further, the end portion of the output pinion shaft opposite to the pinion side serves as a spline shaft and projects from the speed reducing portion to serve as an input end for steering torque from the steering wheel in front of the vehicle body. It is a solution to the problem.

[0007]

In the forklift of the type in which the battery space is expanded to almost the bottom of the vehicle body in order to increase the capacity of the battery, a space for arranging the transmission device and the steering driving tool associated with the electric power steering under the battery. It is possible to electrify the steering device with the minimum required.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a forklift A has two front wheels C in front of a vehicle body B and two rear wheels D in the rear thereof, and a battery E reaching a bottom portion in the center of the vehicle body B.
Are supported and stored by holding means (not shown). Further, the forklift A is a motor with a speed reducer for driving, in which the front wheels C are driven and controlled by operating an accelerator pedal and a brake pedal installed on the floor F (neither is shown).
The front wheels are driven by driving the front wheels C. Since the rear wheel D is for steering and is not provided with a driving device such as a motor, a space is secured between the left and right sides of the rear wheel D.

A method of transmitting torque from the steering wheel 1 to the rear wheel D of this embodiment will be described below with reference to the drawings. First,
If the driver of the forklift A wants to make a turn,
Rotate the handle 1. The handle shaft 2 rotates through the handle 1 rotated by the driver. The rotational force of the handle shaft 2 is transmitted to the first sprocket wheel 4 on the lower front side of the floor F by slightly changing the rotational direction at the first joint 3. The rotational force transmitted to the first sprocket wheel 4 is transmitted to the second sprocket wheel 6 below the floor F via the chain 5. Below the second sprocket wheel 6, an input shaft of a steering torque detector 7 fixed to a frame near the front of the battery E is installed integrally with the second sprocket wheel 6. The steering wheel turning force detected by the steering torque detector 7 is input to a controller (not shown) to drive an actuator 15 described later. Steering torque detector 7
The rotational force transmitted to the shaft of the second joint 8 slightly changes the rotation direction, and the first bevel gear 9A at the bottom of the vehicle body is changed.
It is transmitted to. The rotational force transmitted to the first bevel gear 9A is
It is transmitted to the second bevel gear 9B that meshes with the first bevel gear 9A. At this time, the rotation axis changes 90 ° from the vertical direction to the horizontal direction of the vehicle body (FIGS. 4 to 6). The rotational force transmitted to the second bevel gear 9B passes through the lower side of the battery E substantially horizontally in the front-rear direction of the vehicle body.
It is transmitted to the rear of the car body through 0. This third joint 1
The rear part of 0 is the input shaft 1 of the steering drive device at the rear of the vehicle body.
1 is a spline hole for transmitting the rotational force.
The transmission device of the manual torque transmission mechanism extends to the third joint 10 that transmits to the input shaft 11 of the steering drive tool (FIGS. 2 and 3).

The rotational force transmitted to the input shaft 11 of this steering drive is transmitted to the pinion 12 at the end opposite to the input shaft. Rotational force from the handle 1 is output to the rack 13 by the pinion 12. In addition to this, there are a cylinder 14 that supports the rack 13 so as to be swingable to the left and right, and an actuator 15 in which a drive mechanism including a motor 15A and a speed reduction unit 15B is integrally fixed to the cylinder 14 (FIGS. 10 to 13). This actuator 15
Operates according to the torque detected by the steering torque detector 7 to move the rack 13. The rack 13 also functions as a relay rod of a steering mechanism, and has tie rods 16 swingably connected to both left and right ends thereof, and the left and right swings of the rack 13 cause the rear wheel C (steering wheel) via the tie rods 16 and knuckle arms 17. Wheels turn (FIGS. 7-9). The rack 13 meshes with a counter gear 18 driven by the output pinion 12 from the speed reducer 15B and swings left and right as the counter gear 18 rotates. These steering drive tools are substantially diamond-shaped bottom members installed in a space secured between the left and right rear wheels D,
It is built in and fixed to a bucket-shaped rear axle frame 19 composed of rib members surrounding the periphery.

[0012]

According to the present invention, the space under the battery may be small, so that the battery can be dropped to the lower side of the vehicle body and a large capacity battery can be mounted. In addition, the vehicle body can be lowered even when a normal battery is mounted, which makes it easier to get on and off the vehicle and lowers the vehicle height.

[Brief description of drawings]

FIG. 1 shows a side view of a counterbalanced battery-powered forklift.

FIG. 2 shows a side perspective view of a counterbalanced battery forklift.

FIG. 3 shows a top perspective view of a counterbalanced battery forklift.

FIG. 4 shows a top perspective view of a bevel gear.

FIG. 5 shows a side perspective view of a bevel gear.

FIG. 6 shows a rear perspective view of a bevel gear.

FIG. 7 shows a top view of the rear axle.

FIG. 8 shows a rear view of the rear axle.

FIG. 9 shows a side view of the rear axle.

FIG. 10 shows a front view of a steering driving tool.

FIG. 11 is a rear view of the steering driving tool.

FIG. 12 shows a side view of a steering drive tool.

FIG. 13 shows a side perspective view of a steering driver.

[Explanation of symbols]

A counterbalanced battery-powered forklift truck B vehicle body C front wheel D rear wheel E battery F floor 1 handle 2 handle shaft 3 first joint 4 first sprocket wheel 5 chain 6 second sprocket wheel 7 steering torque detector 8 second Joint 9 Bevel Gear 9A First Bevel Gear 9B Second Bevel Gear 10 Third Joint 11 Input Shaft 12 Pinion 13 Rack 14 Cylinder 15 Actuator 15A Motor 15B Reduction Gear 16 Tie Rod 17 Knuckle Arm 18 Counter Gear 19 Rear Axle Frame

Claims (2)

[Claims] 1. A vehicle body, a battery loaded in the center of the vehicle body and reaching near a bottom portion of the vehicle body, two front wheels disposed in front of the battery and driven by the vehicle body, and disposed behind the battery in the vehicle body and A torque detector, a motor, and a decelerator that has two rear wheels that are turned and that rotates a steering wheel in front of the driver seat that is disposed on the upper surface of the battery to detect the driving force transmitted through the transmission device and the steering torque of the steering wheel. In a counterbalanced battery type forklift truck (hereinafter, referred to as a forklift truck) that combines a driving force with a steering driving tool that is composed of a unit, and turns the rear wheels, the transmission device includes a first handle shaft that is rotated by a handle. The first sprocket wheel connected via a joint and the front of the battery under the driver's floor. A second sprocket wheel integral with the input shaft of the near of the steering torque detector that is fixed to the frame, the two
A chain connecting two sprocket wheels, a first bevel gear connected to the output shaft of the steering torque detector via a second joint, a second bevel gear meshing with the first bevel gear, and a rotation of the second bevel gear. Steering mechanism for a forklift, which is a manual torque transmission mechanism consisting of a third joint that transmits the lower part of the battery horizontally to the input shaft of the steering mechanism behind the vehicle body. 2. The forklift according to claim 1, wherein the steering driving tool includes a bucket-shaped rear axle frame including a substantially rhombic bottom member and a rib member surrounding the bottom member, and a cylinder for swingably supporting the rack to the left and right. A rack-and-pinion steering mechanism is characterized in that an actuator in which a drive mechanism including a motor and a speed reduction unit is integrally fixed to the cylinder is fixed internally. The rack also functions as a relay rod of a steering mechanism, and tie rods are swingably connected to the left and right ends of the rack, and the steering wheel pivots via the tie rod and the knuckle arm by the left and right swings of the rack. The rack meshes with a counter gear driven by an output pinion from the speed reducer, and swings left and right as the counter gear rotates. A steering mechanism for a forklift having a structure in which an end portion of the output pinion shaft opposite to the pinion side serves as a spline shaft and projects from the speed reducing portion to serve as an input end for steering torque from a steering wheel in front of the vehicle body.