JP2857518B2 - Battery-powered three-wheeled 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 battery-powered three-wheel forklift in which steering torque of a steering wheel is transmitted to a torque detector provided in a rear wheel power steering device through a transmission device having a simple structure.

[0002]

2. Description of the Related Art In order to improve the operability of a steering wheel, a three-wheel forklift using a power steering device is being used.

On the other hand, a battery-powered three-wheeled forklift driven by a battery is used to protect the surrounding environment.
The battery-driven three-wheel forklift is loaded with a battery reaching the bottom at the center of the vehicle body, which is often used instead of the internal combustion engine driven type.

Further, in this battery-type three-wheel forklift, a front-wheel drive type for driving the front wheels and a rear-wheel drive type for driving the rear wheels are conceivable. Turn the rear wheel mainly.

[0005] By the way, there is a battery type three-wheel forklift having an electric power steering device as a type for driving the rear wheels.

[0006]

However, since this type employs a rear-wheel drive type, the volume of equipment around the rear wheel, such as a drive motor, becomes large. A power steering device such as a steering motor, deceleration unit, torque detector, etc. is arranged on the front wheel side,
The rear wheel steering shaft and the power steering device are connected by a chain type transmission.

As a result, the torque to be transmitted by the chain becomes extremely large, and the chain size, the chain wheel, and the like become large in order to withstand the chain tension. The turning of the steering shaft was not smooth. Since the space below the battery is small, if the chain size is not increased accordingly, durability is poor and maintainability is impaired.

[0008] For this reason, when a hydraulic power steering system is employed, the motor always rotates, the noise and the energy loss are large, and the reference position of the handle, which is the position of the knob when the vehicle is traveling straight, is determined. There is a problem that the rotational position changes with use.

The present invention is a battery-powered three-wheeled forklift, which has been completed as a result of various developments to improve the electric power steering system described above. It is an object of the present invention to provide a battery-powered three-wheel forklift with improved power steering performance and improved durability based on the provision of a device.

[0010]

SUMMARY OF THE INVENTION The present invention comprises a vehicle body, a battery mounted at the center of the vehicle body and reaching the bottom of the vehicle body, front wheels disposed on and driven by the vehicle body on both front sides of the battery, and a rear side of the battery. A battery-powered three-wheel forklift having a rear wheel that is disposed on a vehicle body and that is not driven at a center, the vehicle-backed three-wheel forklift having a rear wheel steering shaft that supports the rear wheel and a motor behind the vehicle body, and turning the rear wheel steering shaft. A power steering device comprising a steering driver for generating an assist torque and a torque detector for detecting a steering torque from the steering wheel acting on an input shaft connected to a steering wheel in front of the vehicle body via a transmission device; The transmission has a first chain wheel at the lower end of the handle and a second chain at the upper end of the intermediate shaft vertically pivoted in front of the battery. , A first-stage transmission means for connecting the first and second shafts, a third shaft at the lower end of the intermediate shaft, and a lower end of a first vertical shaft which is vertically supported by a first bearing box disposed behind the battery. Second transmission means connected to the fourth chain wheel by a chain passing under the battery, and a fifth chain wheel at the upper end of a second vertical shaft vertically supported by a second bearing box at the upper rear part of the vehicle body. And a sixth stage connected to the input shaft by a chain, and a connecting shaft connecting the first and second vertical shafts via a universal joint. This is a battery-powered three-wheeled forklift.

[0011]

By providing front wheel drive and rear wheel steering, a space is secured in the rear wheel portion, so that a power steering device can be provided in the space.

Also, by linking the handle shaft to the input shaft of the torque detector of the power steering device via a chain-based transmission device, the transmission device transmits a small torque for turning the input shaft of the torque detector. Therefore, the transmission torque of the transmission device is reduced, and the transmission device is reduced in size. As described above, it becomes easier to provide the transmission device below the battery. The shaft is directly driven by the steering driver without passing through the chain, so that turning is smooth.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, a battery-type three-wheel forklift T includes two front wheels 4 and 4 at the front of a vehicle body 3 and one
Along with the two rear wheels 5, a battery B reaching the bottom is supported and accommodated in the center of the vehicle body 3 by holding means (not shown).

The battery type three-wheel forklift T is
The front wheel 4 is driven by mounting a motor with a reduction gear (not shown) for traveling, which is driven and braked by operating an accelerator pedal and a brake pedal, on the front wheel 4.

The rear wheel 5 is for steering and has no driving device, so that a space around the rear wheel 5 is secured.

A power steering device 1 is arranged behind the vehicle body 3 and the power steering device 1
Is connected to the handle 6 by a transmission device 7 using a chain.

In the present embodiment, the power steering device 1 includes a rear wheel steering shaft 10, a steering driving tool 11 having a motor M for steering and capable of turning the rear wheel steering shaft 10, and the transmission device 7. And a torque detector 14 having an input shaft 13 linked to the steering wheel 6, and in this example, as shown in FIGS.
Housing 15 for supporting rear wheel steering shaft 10
And the input shaft 13 is linked to the speed reduction portion 16 of the steering driving tool 11.

As shown in FIG. 3, the housing 15 has a base 17 having a flange 20 fixed to the horizontal portion 19 of the vehicle body 3, and a rear wheel steering shaft provided by a bearing and a seal (not shown) provided on the base 17. 11 is pivoted vertically and a nut 22 protrudes from the housing 15.
It is stopped by.

As shown in FIG. 4, a cam plate 23 for fixing a turning range of the rear wheel steering shaft 10 to the rear wheel steering shaft 10 using micro switches S, S is fixed to the protruding end. As shown in FIG. 3, an L-shaped wheel bracket 26 to which a support shaft of the rear wheel 4 is attached and a large gear 27 which is ported to the upper surface thereof are fixed to the projecting portion downward from the housing 15. I have.

As shown in FIG. 5, the steering driving tool 11 includes the steering motor M fixed on the upper surface of the housing 15 and the speed reduction unit 16 disposed in the housing 15.

The speed reducer 16 includes an output shaft 32 provided with gears, a hollow intermediate shaft 33 provided with gears and pinions, and a gear shaft supported above the output shaft 32 in parallel with the motor shaft 31 provided with pinions. The intermediate gears 34 having pinions are sequentially meshed, and the rotation speed of the motor M is reduced by, for example, three-stage gear means, so that the output shaft 32 can be rotated at a low rotation speed and a high torque.

At the lower end of the output shaft 32, a small gear 35 meshing with the large gear 27 of the rear wheel steering shaft 10 is provided.
Is fixed.

The torque detector 14 is connected to the housing 1
5, the input shaft 13, which is upward and perpendicular to the input shaft 4, is disposed concentrically below the input shaft 4, and a downwardly projecting portion from the case 40 is provided with the hollow intermediate shaft 33. The input shaft 13 is provided with a sliding shaft 42 that can move up and down in parallel with the input shaft 13 and the connecting shaft 41.

The lower end of the input shaft 13 is provided with a first spur gear G1.
A helical gear G2 having substantially the same pitch circle diameter as the first spur gear G1 is arranged at the upper end of the connecting shaft 41, and the first spur gear G1 and the first helical gear G2 are arranged on the sliding shaft 42. The second spur gear g1 and the second helical gear g2 meshing with each other are integrally and integrally pivotally connected to the slide shaft 42 so as not to be movable in the axial direction, whereby the first spur gear G1 and the first helical gear A well-known subtraction mechanism that takes out the rotational deviation between G2 as the vertical movement of the slide shaft 42 and detects the amount of movement by a potentiometer 45 is formed.

As the torque detector 14, various sensors such as a differential transformer can be used in place of the potentiometer 45, and the torque detector 14 can detect a steering torque, such as a torque meter using a strain gauge. Various things can be used as long as they are provided.

In this embodiment, the first spur gear G1 and the first helical gear G2 are connected via an elastic coupling C.

The elastic coupling C transmits the rotation of the input shaft 13 to the connecting shaft 41 via the elastic piece 44, thereby reducing the force acting on the second spur gear g1 and the second helical gear g2. The smoothness of the vertical movement of the sliding shaft 42 enhances the detection accuracy of the potentiometer 45.

In this embodiment, the elastic coupling C is provided as shown in FIG.
, The first helical gear G of the first spur gear G1
The center pin 46 and the circumferential wall 47 are provided concentrically on the surface facing 2 and the four arc-shaped operating pieces 49A to 49D provided inside the circumferential wall 47 at substantially equal angular pitches, and two regulating pieces 50, 50. And the operation piece 49A and the operation piece 49B, and the operation piece 49C and the operation piece 4 passing through both sides of the center pin 49.
The elastic piece 44 is provided in the form of a leaf spring and held at each of the opposed edges of the 9D.

The first helical gear G2 is provided with four arcuate driven pieces 51A to 51D indicated by dashed lines and concentric with the working pieces 49A to 49D and radially inside.
The facing edges of the driven pieces 51A and 51B and the driven pieces 51C and 51D are in contact with the elastic pieces 44.

As a result, the one-way rotational torque acting on the input shaft 13, ie, the first spur gear G1, is applied to the elastic pieces 44 by the operating pieces 49A and 49C as shown in FIG.
While being bent, the driven pieces 51B, 5
While transmitting the rotational torque to 1D, a rotational displacement occurs,
By transmitting the rotational torque to the connecting shaft 41 via the elastic piece 44, the force acting on the spur gear g1 and the second helical gear g2 is reduced.

Accordingly, the steering torque acting on the steering wheel 6 is transmitted to the input shaft 13 by the transmission device 7 and a positive / negative torque signal obtained by detecting the steering torque by the torque detector 14 is transmitted to a control device (not shown). The control device rotates the motor M of the steering driving tool 11 at a predetermined auxiliary torque and speed to rotate the rear wheel steering shaft 10 to perform electric power steering.

As described above, in the present embodiment, the battery type three-wheel forklift T is a front-wheel drive, and the housing 15 for supporting the rear-wheel steering shaft 10 is integrally assembled with the steering drive 11 and the torque detector 14. Since the power steering device 1 is used, the size of the device is reduced.

The input shaft 13 of the torque detector 14 is linked to the intermediate shaft 33 of the speed reducer 16 of the steering driving tool 11 via the elastic coupling C and the connecting shaft 41, so that the assisting torque by the steering driving tool 11 is provided. Is transmitted to the steering wheel sensitively, and a high-precision auxiliary torque can be applied. In addition, by linking to the intermediate shaft 33, even in the event of a failure of the motor M, the steering wheel 6 allows the rearward rotation of the motor M with a large torque via the speed reduction unit 16. The shaft steering shaft 10 can be turned.

Further, since the steering driving tool 11 is located on the rear wheel 4 side, the transmission torque of the chain type transmission device 7 between the steering wheel 6 and the torque detector 14 can be reduced, and the size can be reduced. It is easy to attach to

As described above, the transmission device 7 connects the handle shaft 52 connected to the handle 6 in front of the vehicle body 3 and the input shaft 13 of the torque detector 14.

The handle shaft 52 is inserted into a bearing barrel 53 supported at the front of the vehicle body 3 so as to be tiltable, and has a lower end having a lower end fixed to the vehicle body 3 using a universal joint. A lower handle shaft 54 coupled to the upper end of the shaft 54;
A first chain wheel S1 is fixed to the lower end.

Further, a bearing cylinder 57 for vertically supporting the intermediate shaft 55 is fixed to a vertical lower plate disposed in front of the battery B of the vehicle body 3, and a second chain wheel is provided at the upper end of the intermediate shaft 55. S
2 is fixed.

The first and second chain wheels S1 and S2 are shown in FIG.
As shown in the figure, the first-stage transmission means P1 is constituted by being connected by a chain C1 via three idle chain wheels SA, SB, SC.

As shown in FIG. 1, the idle chain wheel SA has a slide fitting 5 fixed so that the front and rear positions can be changed.
9 functions as a tensioner for adjusting the tension of the chain C1. Note that the idle chain S
B and SC may be tensioners.

The lower end of the intermediate shaft 55 extends below the lower surface of the battery B, and the third chain wheel S3 is fixed to the lower end.

Further, behind the battery B, a first bearing box 61 on a lower plate 60 of the vehicle body 3 and a second bearing box 62 above the first bearing box 61 are arranged.

As schematically shown in FIG. 8, the first bearing housing 61 has a front wall left on both sides of the bottom plate 64 to raise the side wall 65, and a rear end of the upper end of the side wall 65 is pivoted about a first vertical shaft 67. It is covered by a bearing cylinder 69 that supports it.

In the bottom plate 64 are elongated holes 70, 70 extending back and forth, and fixing the bottom plate 64 at the front and rear positions variably with bolts.
And a screw shaft 71 in the front-rear direction, which is screwed to a standing piece rising at the front edge, presses the contact piece 72 of the lower plate 60 as the screw is retracted, and forms a tensioner that moves the first vertical shaft 67 backward. I do.

A fourth chain wheel S4 at the lower end of the first vertical shaft 67
And the third chain wheel S3 and the chain C2 surrounding the third chain wheel S3 constitute a second-stage transmission means P2, and the tension can be absorbed and the tension adjusted by the tensioner.

As shown schematically in FIG. 9, the second bearing housing 62 has a second vertical shaft provided at one end of a lever plate 76 pivotally supported at the center by a horizontal projection 74 provided on the vehicle body 3. The bearing box 62 that pivotally supports 77 is provided. At the other end of the lever plate 76, there is provided a screw shaft 90 which is screwed to the standing piece.
Forms a tensioner that separates the first vertical shaft 77 from the input shaft 13 of the torque detector 14 by bringing the first vertical shaft 77 into contact with the contact piece 91 of the vehicle body 3.

The projecting ends of the first and second vertical shafts 67 and 77 are connected via two universal joints and a joint shaft 94. A fifth chain wheel S5 at the upper end of the second vertical shaft 77;
The sixth chain wheel S6 of the input shaft 13 and the chain C3 that goes around them form a third-stage transmission means P3.

Accordingly, the steering torque of the handle 6 is controlled by the handle shaft 52, the lower handle shaft 54, the first-stage transmission means P1,
The torque can be transmitted to the input shaft 13 of the torque detector 14 by the intermediate shaft 55, the second-stage transmission means P2, the joint shaft 94, and the third-stage transmission means P3. The slack in each of the chains C1 to C3 is absorbed by the tensioner, and the steering torque can be transmitted smoothly and correctly.

As a result of such a configuration, the steering driving tool 1
The transmission torque can be greatly reduced and the chain used can be reduced in size as compared with the case where the first steering motor M is provided at the front of the vehicle body.
It becomes easy to arrange the second-stage conduction means P2 including the chain C2 below. In addition, since the chain is reduced in size, it is easy to remove the rotation unevenness due to the polygonal movement of the chain, so that the transmission is smooth and the transmission accuracy is improved. Also, the first vertical shaft 77 is disposed on the first bearing housing 61, and
By covering the fourth wheel S4 with the bearing box 61, the fourth wheel S4 can be prevented from being soiled by mud splashing even when the fourth wheel S4 is disposed near the rear wheel 5.

[0049]

As described above, according to the device of the present invention, the front wheel drive and the rear wheel steering make it possible to secure a space in the rear wheel portion and to provide a power steering device in the space. In addition, by linking the steering wheel to the input shaft of the torque detector of the power steering device via a transmission device using a chain, the transmission device transmits a small torque that turns the input shaft of the torque detector. In addition to making the power transmission device smaller under the battery, it is easier to provide the transmission device underneath the battery, enhancing durability and maintainability, and turning the rear wheel steering shaft by being directly driven by a steering driver without passing through a chain. Becomes smoother.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a vehicle body according to an embodiment of the present invention.

FIG. 2 is a plan view schematically showing a vehicle body according to an embodiment of the present invention.

FIG. 3 is a partially sectional front view illustrating the power steering device.

FIG. 4 is a plan view illustrating a power steering device.

FIG. 5 is a cross-sectional view illustrating a steering driving tool and a torque detector.

FIG. 6 is a perspective view illustrating an elastic coupling used in the torque detector.

FIG. 7 is a plan view showing the operation.

FIG. 8 is a perspective view illustrating a first bearing housing of the transmission device.

FIG. 9 is a perspective view illustrating a second bearing housing of the transmission device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power steering device 3 Body 4 Front wheel 5 Rear wheel 6 Handle 7 Transmission device 10 Rear wheel steering shaft 11 Steering drive 13 Input shaft 14 Torque detector 15 Housing 16 Reduction part 53 Handle shaft 55 Intermediate shaft 61 First bearing box 62 Second bearing housing 67 First vertical shaft 77 Second vertical shaft 94 Joint shaft M Motor C1, C2, C3 Chain P1 First stage conduction means P2 Second stage conduction means P3 Third stage conduction means S1 First Wheel S2 Second wheel S3 Third wheel S4 Fourth wheel S5 Fifth wheel S6 Sixth wheel

Claims (2)

(57) [Claims] 1. A vehicle body, a battery loaded at the center of the vehicle body and reaching the bottom of the vehicle body, front wheels disposed and driven on the vehicle body on both front sides of the battery, and a vehicle body disposed and driven at the rear center of the battery. A battery-powered three-wheel forklift having a rear wheel that is not provided, a rear wheel steering shaft supporting the rear wheel, a motor behind the vehicle body, and a steering driver that generates an auxiliary torque for turning the rear wheel steering shaft, And a power steering device comprising a torque detector for detecting a steering torque from the steering wheel acting on an input shaft connected to a steering wheel in front of the vehicle body via a transmission device, while the transmission device is provided at a lower end of the steering wheel. A chain connecting a first chain wheel and a second chain wheel at the upper end of an intermediate shaft vertically pivotally supported in front of the battery by a chain. A step transmission means, the intermediate shaft, a third wheel at the lower end of the intermediate shaft, and a fourth wheel at the lower end of the first vertical shaft which is vertically supported by a first bearing box disposed behind the battery. A second-stage transmission means connected by a chain passing under the battery, a fifth chain wheel at the upper end of a second vertical shaft vertically supported by a second bearing box at the upper rear portion of the vehicle body, and a fifth attachment wheel attached to the input shaft. A battery type three-wheel forklift comprising: a third-stage conductive means for connecting the chain wheel to a chain wheel of No. 6 with a chain; and a connecting shaft connecting the first and second vertical shafts via a universal joint. Wherein said first, second is the bearing housing battery-powered three-wheeled truck of claim 1, wherein in that the adjustable position back and forth.