JPH06247334A - Reach forklift - Google Patents

Abstract

PURPOSE:To provide an enhanced driving feel by permitting rotation of the input and output shafts of a steering wheel to be switched between normal and reverse directions, in a steering unit which can control the steering angle of a road wheel in phase with that of a drive wheel. CONSTITUTION:When a forklift is in the normal mode, no power is transmitted to a rotary solenoid 33, and rotation of an arm piece 29 due to a spring force causes rotation of an arm piece 53 which is integrated with a rotating shaft 25, so that a ring gear 17 and an internal gear 10 are locked by the lower claw portion of the arm piece 53, and that the upper claw portion of the arm piece 53 is unlocked from the toothed portion 4A of a carrier 4. In this state, rotation of the input shaft 2 of the steering wheel causes rotation of an output shaft (sprocket) 21 in the same direction as that in which the input shaft 2 is rotated. In the in-phase mode, power is transmitted to the rotary solenoid 33 and thereby the carrier 4 is locked, the lower claw portion unlocks the gears, and the output shaft 21 is rotated in the direction opposite to that in which the input shaft 2 is rotated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reach-type forklift truck, and more particularly to a reach-type forklift truck equipped with a steering unit capable of switching the rotation directions of an input shaft and an output shaft of a steering wheel according to circumstances.

[0002]

2. Description of the Related Art In recent years, as represented by Japanese Patent Application No. 3-306767 previously proposed by the present applicant, a forklift has been proposed which is an improved reach type forklift and is capable of various driving modes. ing.

As shown schematically in FIG. 5, the forklift 61 has a body 62 and left and right straddle arms 68, 68 projecting from the body 62. The body 6
2 is provided with a drive wheel 52 that can be steered by a steering wheel 3.

The drive wheel 52 is supported on a main body portion 62 by a swivel swivel gear 49 mechanically linked to the handle 3, and a potentiometer 50 capable of detecting the amount of rotation is attached to the swivel gear 49. Accordingly, the steering angle of the drive wheel 52 can be detected. still,
Although not shown, caster wheels are provided on the side of the drive wheel 52 to ensure traveling stability.

Between the straddle arms 68, 68 is mounted a cargo handling tool 74 which can slide forward and backward and can be moved up and down by a lift cylinder (not shown).

The road wheels 64 and 65 are rotatably supported by swivel brackets 66 and 67 which are swivelable with respect to a straddle arm 68, and the steering motor 7 is provided via conductive members 69 and 69 such as chains or belts.
0 and 71 are attached respectively. Therefore, the left and right road wheels 64 and 65 can be steered by rotating the steering motors 70 and 71.

The output shafts of the steering motors 70 and 71 are provided with potentiometers 7 capable of detecting the amount of rotation thereof.
2, 73 are attached, left and right road wheels 64, 65
Is configured to detect the steering angle of the vehicle.

The forklift 6 constructed as described above
1 operates the switches A and B of the driving mode selection device 63 to execute a desired driving mode based on a control pattern stored in a control device (not shown).

For example, when the switch A is selected, as shown in FIG.
As shown in (A), the steering angle θ of the drive wheel 52
Is detected and feedback control is performed so as to match this with the steering angles of the road wheels 64 and 65, so that the so-called in-phase mode capable of moving without changing the attitude of the vehicle can be selected.

On the other hand, when the switch B is selected, as shown in FIG.
As shown in (B), the steering angles θ of the drive wheels 52 are set with the steering angles of the left and right road wheels 34 and 35 both set to zero.
It is possible to switch to the normal mode in which the steering is carried out only along the line.

[0011]

By the way, in the reach type forklift 61, in order to make the rotation direction of the steering wheel 3 coincide with the traveling direction of the vehicle, the rotation of the steering wheel 3 is changed to the steering pinion as shown in FIG. A pair of spur gears 48 and a turning gear 49 are configured to be transmitted to the drive wheel 52. That is, since the steering system is the rear wheel steering system, the rotation direction of the steering wheel 3 is opposite to the steering direction of the drive wheel 52.

However, although such a configuration is suitable in the normal mode, when the in-phase mode as described above is selected, the rotation direction of the handle 3 and the traveling direction of the forklift 61 are completely opposite, It causes a problem of extremely bad driving feeling.

The present invention has been devised to solve such a problem, and an object thereof is to provide a forklift equipped with a steering unit capable of freely switching the rotation directions of an input shaft and an output shaft of a steering wheel between forward and reverse directions. To provide.

[0014]

SUMMARY OF THE INVENTION According to the present invention, a load wheel that is steerably supported in the vicinity of the tip of each of the left and right straddle arms, and a drive means that can steer the load wheel are housed in the straddle arm. A drive wheel, which is arranged and is steered by a steering wheel, is provided at the rear of the vehicle body, and the left and right road wheels and steering angle detection means capable of detecting the steering angle of the drive wheel are provided to drive the steering angle of the road wheel. A reach type forklift capable of switching control in the same phase as a wheel steering angle, the input shaft fixed to a steering wheel, and an output shaft provided coaxially with the input shaft. Is linked to a drive wheel, and the input shaft is provided with two planetary gear mechanisms such that two sun gears are vertically arranged side by side. The internal gear and the carrier of the other planetary gear mechanism are fixed to each other, and the carrier or the internal gear of each planetary gear mechanism is formed with a toothed portion on its outer peripheral edge, and the lock lever meshes with each toothed portion. Is rotatably supported at a position in which the center of the rotary shaft is closely attached to the pitch circle of the toothed portion, and the arm piece fixed to the rotary shaft is connected to the rotary solenoid. In addition, when the rotary solenoid is de-energized, the steering unit has a steering unit in which a spring for urging one of the lock levers to engage with one of the toothed portions is connected to the arm piece. It is a characteristic reach type forklift.

[0015]

When the forklift is currently selected in the normal mode, the rotary solenoid 33 is de-energized. In this state, the rotary solenoid 33 is in a free state, but due to the restoring force of the spring 32,
The arm piece 29 rotates the rotary shaft 25 in the direction of arrow R about the axis XX. As a result, the ring gear 17 and the internal gear 10 are locked by the lower claw portion 40 of the arm piece 53, and at the same time, the upper claw portion 39 of the arm piece 29 is disengaged from the tooth-shaped portion 4A of the carrier 4 and unlocked. .

Here, the torque of the input shaft 2 is the same as the sun gear 14, the planetary gear 11, and the planetary gear 11 of the second planetary gear mechanism G2.
Through the planetary shaft 12 and the carrier 18, it is transmitted to a sprocket 21, which is an output shaft fastened to the carrier 18 with a key 22.

However, the direction of rotation of the sprocket 21 is
Since the ring gear 17 of the second planetary gear mechanism G2 is fixed, it becomes a planetary type and rotates in the same direction as the input shaft 2 (normal rotation). At this time, the ring gear 17
The inner surface of the sprocket 21 can support the carrier 18 and prevent the rotation of the sprocket 21 from becoming unstable.

Further, in the transmission system after the sprocket 21,
As described above, there is only one pair of spur gears, and therefore the handle 3 and the drive wheel 52 rotate in opposite directions.
Since the first planetary gear mechanism G1 is in the free state, it is in the idling state.

Next, when the forklift is in the same phase mode, the rotary solenoid 33 is energized. As a result, the rotary plate 36 of the rotary solenoid 33 rotates in the direction of arrow E (see FIG. 3), resisting the restoring force of the spring 32, and the arm piece 29 moves the rotary shaft 25 about the axis X-X. Rotate in the direction of arrow L. As a result, the carrier 4 is locked by the upper claw portion 39 of the arm piece 29, and at the same time, the lower claw portion 40 of the arm piece 53 is disengaged from the tooth-shaped portion 17A of the ring gear 17 to be unlocked.

Here, the torque of the input shaft 2 passes through the sun gear 13, the planetary gear 6, the internal gear 7, the planetary shaft 12, the carrier 18 of the first planetary gear mechanism G1, and the carrier 18 and the key. It is transmitted to the sprocket 21, which is the output shaft fastened at 22.

However, the direction of rotation of the sprocket 21 is
Since the carrier 4 of the first planetary gear mechanism G1 is fixed, it becomes a star type and rotates in the direction opposite to the input shaft 2.

In this case, finally, the handle 3 and the drive wheel 52 rotate in the same direction. Also, the second
Since the planetary gear mechanism G2 is in a free state, it is in an idling state.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. According to the present invention, the torque is applied to the steering shaft of the input shaft 2 fixed to the steering wheel 3.
Is transmitted to the sprocket 21, which is an output shaft, and is connected to the sprocket 21 by a chain parallel to the sprocket 21, a steering pinion 48 driven in the same direction as the sprocket 43, and a turning engagement with the steering pinion 48. The gear 49 and the swing gear 4
9 and a gear case 51 that supports a drive wheel 52. In addition, a torque sensor 44 for power steering, a universal joint 45,
An electric motor 46 and a speed reducer 47 are provided.

The steering unit 1 has a first
The planetary gear mechanism G1, the second planetary gear mechanism G2, and the switching device 60. The switching device 60 receives a control signal from the traveling mode selection device 70 in this example.

The first planetary gear mechanism G1 includes a carrier 4 rotatably supported on the input shaft 2 via a ball bearing 23,
A planetary shaft 5 fixed downward to the carrier 4, a planetary gear 6 rotatably mounted on the planetary shaft 5 via a bush, an internal gear 7 meshed with the planetary gear 6, and an internal gear. It comprises a carrier 8 for fixedly supporting the gear 7 and a sun gear 13 which meshes with the planetary gear 6 and is connected to the input shaft 2 by a key.

The internal gear 7 is the sun gear 1.
It is rotatably supported via a ball bearing 15 mounted on the outer peripheral edges of the members 3 and 14. A toothed portion 4A is formed on the outer peripheral edge of the carrier 4. It is desirable that the tooth groove portion 4A of the carrier 4 is a standard gear having a pressure angle of 20 degrees and a large number of teeth.

Similarly, the second planetary gear mechanism G2 includes a planetary shaft 12 projecting downward from the carrier 8, and a planetary gear 11 rotatably mounted on the planetary shaft 12 via a bush. An internal gear 10 meshed with the planetary gear 11, and an outer carrier 17 for fixedly supporting the internal gear 10,
The inner carrier 18 slidable with respect to the outer carrier 17
Composed of and.

Tooth-shaped portions 17A having the same pitch circle as the carrier 4 are formed on the outer peripheral edge of the outer carrier 17. The inner carrier 18 is rotatably attached to the input shaft 2 via a ball bearing 24.

A sprocket 21, which is an output shaft, is fitted into and mounted on the inner carrier 18 via a key 22, and an outer peripheral surface of the sprocket 21 is supported by a bearing portion 20 and a ball bearing 19.
It is rotatably supported by. The planetary shaft 12 projects to the inner carrier 18.

The switching device 60 includes a rotary shaft 25 rotatably supported by bearings 37 and 38 in a vertically rotatable manner, and the rotary shaft 25.
It is composed of arm pieces 29 and 53 arranged above and below, and a rotary solenoid 33 capable of swinging the arm piece 29.

The rotary shaft 25 has a cutout surface 26 of approximately half in a part thereof, and is constructed so as to be as close as possible to the pitch circle of the toothed portion 4A of the carrier 4. In this way, the center of rotation of the rotary shaft 25 is set to the toothed portion 4A of the carrier 4.
By approaching the carrier 4, the moment that allows the arm piece 29 received from the carrier to be disengaged from or caught in the carrier 4 is reduced, and smooth switching can be performed. Moreover, since the rotary solenoid 33 for driving the rotary shaft can employ a small output, the size can be reduced. The rotary shaft 25
Both end portions 27, 28 of the are rotatably supported by bearings 37, 38.

The arm piece 29 is fixed to the upper side of the rotary shaft 25, an upper claw portion 39 is formed on one end side, and a long hole into which the pin 34 of the rotary solenoid 33 can be inserted on the other end side. 30 is formed. Further, in this example, the engaging portion 31 is provided on the rotary solenoid 33 side of the arm piece 29.
Is fixed, and the spring 32 constantly urges the rotating shaft 25 to rotate toward the arrow “R” side.

In this embodiment, the rotary solenoid 33 employs a rotary plate 36 which is in a free state when not energized and which is energized to rotate the rotary plate 36 in the direction of arrow "E". Therefore, when the rotary solenoid 33 is not energized, the rotating shaft 25 tries to rotate in the direction of the arrow R due to the influence of the spring 32, and when energized, the rotating shaft 25 is rotated.
Tries to rotate in the direction of arrow L. A roller 35 is attached to the pin 34.

In this example, the rotary solenoid 33
Is controlled by the above-mentioned running mode selection device so that current is energized when the in-phase mode is being selected and non-energized otherwise.

In this example, the sun gears 13 and 14, the planetary gears 6 and 11, and the internal gears 7 and 10 each have the same module and the same number of teeth. In phase mode,
The reduction ratio becomes small, and the steering response of the drive wheel with respect to the steering angle of the steering wheel can be improved.

[0036]

According to the present invention, by adopting the above-mentioned structure, the rotation directions of the input shaft and the output shaft of the steering wheel can be switched between the forward and reverse directions depending on the driving mode. You can realize the movement of the vehicle according to the operation,
There is an effect that a good driving feeling can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a steering unit of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a perspective view of a switching device.

FIG. 4 is a schematic diagram of the present invention.

FIG. 5 is a plan view of a conventional reach type forklift.

FIG. 6 is a schematic view for explaining the movement of the reach type forklift.

FIG. 7 is a side view for explaining a steering transmission system.

[Explanation of symbols]

 1 Steering Unit 2 Input Shaft 3 Handle 4 Carrier 5 Planetary Shaft 6 Planetary Gear 7 Internal Gear 8 Carrier 9 Socket Screw 10 Internal Gear 11 Planetary Gear 12 Planetary Shaft 13 Sun Gear 14 Sun Gear 17 Ring Gear 18 Carrier 21 Sprocket

Claims (1)

[Claims] 1. A road wheel, which is steerably supported in the vicinity of the tip of each of the left and right straddle arms, and a drive means capable of steering the road wheel are housed and arranged in the straddle arm. A steerable drive wheel is provided at the rear of the vehicle body, and the left and right road wheels and steering angle detection means capable of detecting the steering angle of the drive wheel are provided, and the steering angle of the road wheel is in phase with the steering angle of the drive wheel. A reach type forklift capable of switching control, comprising an input shaft fixed to a handle, and an output shaft provided coaxially with the input shaft, the output shaft being linked to a drive wheel, The input shaft is provided with two planetary gear mechanisms such that two sun gears are vertically arranged side by side, and the internal gear of the one planetary gear mechanism and the other Of the planetary gear mechanism, the carrier or the internal gear of each planetary gear mechanism is formed with a toothed portion on its outer peripheral edge, and lock levers meshing with the toothed portions are vertically fixed side by side. The rotary shaft is rotatably supported at a position where the center of the rotary shaft is close to the pitch circle of the toothed portion, and the arm piece fixed to the rotary shaft is connected to the rotary solenoid. Reach-type forklift including a steering unit in which a spring for urging one of the lock levers to engage with one of the toothed portions when not energized is connected to the arm piece. .