JP3094136B2 - 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 battery-powered forklift equipped with a power steering device for reducing the impact of a steering wheel at the moment when the steering end is reached and improving the operation feeling.

[0002]

2. Description of the Related Art A vehicle body, a battery mounted 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 disposed and driven on the vehicle body at a rear center of the battery. A rear wheel steering shaft for supporting the rear wheel behind the vehicle body, a steering driver having a motor for generating an auxiliary torque for turning the rear wheel steering shaft, and a transmission device for a steering wheel in front of the vehicle body A power steering device comprising a torque detector for detecting a steering torque from the steering wheel acting on an input shaft connected via the power steering device is disposed, while the transmission device is connected to a first chain wheel at a lower end of the steering wheel and the front of the battery. First-stage conducting means for connecting a second chain wheel at the upper end of the intermediate shaft pivotally supported with a first chain by a chain, the intermediate shaft, and a lower end of the lower end of the intermediate shaft. Second-stage transmission means in which a chain wheel of the vehicle and a fourth wheel chain at the lower end of a first vertical shaft vertically supported by a first bearing box disposed behind the battery are connected by a chain passing under the battery; Third-stage conduction means for connecting a fifth chain wheel at the upper end of a second vertical shaft vertically supported by a second bearing box at the rear upper portion with a sixth wheel shaft attached to the input shaft by a chain. And a lever plate 101 which is pivotally connected at the middle to a horizontal protruding piece 100 provided on the vehicle body 3 as shown in FIG. At one end, the bearing box 62 that supports the second vertical shaft 77 is fixed, and a screw shaft 103 that is screwed to the upright piece 102 at the other end of the lever plate 101 is provided. It is configured to touch.

[0003]

Conventionally, since the above-mentioned structure is employed, the chain, when the steering wheel is vigorously rotated, reaches the end of the steering wheel.
Impact is applied to the mechanism that transmits the steering torque of the bearings and joints, and the above-mentioned chains, bearings, joints, etc. need to have sufficient strength to withstand the impact repeatedly. There is a problem that the impact is unfavorable in the feeling of steering operation.

The present invention is a battery-powered forklift, which has been completed as a result of various developments to improve the above-mentioned electric power steering device, and has been completed. As a basic rule, the impact force at the moment when the steering reaches the end is weakened, and the elements of the chain, bearings, joints, and other mechanisms that transmit steering torque are downsized.
Further, it is an object of the present invention to provide a battery-type forklift having a good handle operation feeling even when the impact is applied.

The present invention is directed to a vehicle body, a battery loaded at the center of the vehicle body and reaching the bottom of the vehicle body, front wheels disposed on the vehicle body on both front sides of the battery, and disposed at the rear center of the battery and not driven. Has a rear wheel,
Acts on a rear wheel steering shaft supporting the rear wheels behind the vehicle body, a steering driver having a motor to generate an auxiliary torque for turning the steering shaft, and an input shaft connected via a steering wheel transmission device in front of the vehicle body. A power steering device comprising a torque detector for detecting a steering torque from the steering wheel is disposed, and the transmission device is provided at a first chain wheel at a lower end of the steering wheel and at an upper end of an intermediate shaft pivotally supported vertically in front of the battery. A first-stage transmission means for connecting the second chain wheel with a first chain, the intermediate shaft, a third chain wheel at a lower end of the intermediate shaft, and a lower end of a first vertical shaft vertically supported behind the battery; Second-stage transmission means connected to the fourth chain wheel by a second chain passing under the battery, a fifth chain wheel at the upper end of a second vertical shaft supported vertically in the rear of the vehicle body A third-stage transmission means for connecting a sixth chain wheel attached to the input shaft with a third chain, and a joint for connecting the first and second vertical shafts via a universal joint; A bearing that supports the upper end of the second vertical shaft is swingably supported via a lever provided on the vehicle body,
Further, the present invention relates to a battery-type forklift, wherein the bearing is oscillated to apply tension to the third chain by interposing a spring between the lever and the vehicle body.

[0006]

The shock torque generated by the inertia of the steering wheel and other rotating parts can be absorbed and alleviated by the deflection of the spring at the moment when the steering wheel is vigorously rotated to reach the steering end.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings, taking a battery type three-wheel fork as an example. In FIGS. 1 and 2, the battery-powered three-wheeled forklift T is
Two front wheels 4, 4 are arranged forward and one rear wheel 5 is arranged rearward. At the center of the vehicle body 3, a battery B reaching the bottom is supported and accommodated by holding means (not shown).

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

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

[0010] Behind the vehicle body 3, a power steering device 1 is arranged.
The handle 6 is linked by a transmission device 7 using a chain.

In the present embodiment, the power steering apparatus 1 includes a rear wheel steering shaft 10, a steering driving tool 11 having a steering motor M 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 the 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 flange 20 fixed to a horizontal portion 19 of the vehicle body 3 on the vehicle body 19, and the rear wheel steering shaft is provided by a bearing and a seal (not shown) provided on the vehicle body 19. 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 by using micro switches S, S is fixed to the projecting 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 bolted to the upper surface thereof are fixed to the projecting portion downward from the housing 15. I have.

As shown schematically in FIG. 5, the steering driving tool 11 comprises the motor M for steering fixed on the upper surface of the housing 15 and the speed reducing portion 16 disposed in the housing 15.

The speed reducer 16 includes an output shaft 32 provided with a gear, a hollow intermediate shaft 33 provided with a gear and a pinion, and a gear shaft supported above the output shaft 32 in parallel with a motor shaft 31 provided with a pinion. 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.

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

Further, the torque detector 14 is provided in 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 and the sliding shaft 42 that can move up and down in parallel with the input shaft 13 are provided.

A first spur gear G1 is provided at the lower end of the input shaft 13.
At the upper end of the connecting shaft 41, a helical gear G2 having substantially the same pitch circle diameter as the first spur gear G1 is arranged, and the sliding shaft 42 is provided with the first spur gear G1 and the first helical gear G2. The second spur gear g1 and the second helical gear g2 meshing with each other are integrally pivotally connected to the sliding shaft 42 so as to be axially immovable relative to each other, 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 vertical movement of the sliding 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. As the torque detector 14, a steering torque such as a torque meter using a strain gauge can be detected. 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 detection accuracy of the potentiometer 45 is enhanced by smoothing the vertical movement of the sliding shaft 42.

In this embodiment, the elastic coupling C is 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 shown by dashed lines and concentric with the operating pieces 49A to 49D and radially inside thereof.
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, that is, the first spur gear G1, 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 integrally assembled with the steering drive 11 and the torque detector 14 in the housing 15 which is driven by the front wheels and pivotally supports the rear wheel steering shaft 10. 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 drive 11 via the elastic coupling C and the connecting shaft 41, so that the assisting torque of the steering drive 11 is 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 wheel steering shaft 10 can be turned.

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 cylinder 53 supported at the front part 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 tube 57 for vertically supporting the intermediate shaft 55 is fixed to a vertical lower floor 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 schematically in FIG. 1, the idle chain wheel SA is provided with 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, 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 behind the battery B.

As shown schematically in FIG. 8, the first bearing housing 61 rises the side wall 65 while leaving the front edge on both sides of the bottom plate 64, and pivots the first rearward end of the side wall 65 around the first vertical shaft 67. It is covered by a bearing cylinder 69 that supports it.

The bottom plate 64 has elongated holes 70, 70 extending back and forth, and fixing the bottom plate 64 at a variable position in the front-rear direction with bolts.
And a screw shaft 71 in the front-rear direction, which is screwed to a standing piece that rises at the front edge, presses the contact piece 72 of the lower plate 60 as the screw is retracted to form 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.

At the other end of a lever 76 pivotally supported at one end by a horizontal projection 74 provided on the vehicle body 3, the bearing box 62 pivotally supporting a second vertical shaft 77 is provided. A screw 90 having a head fixed to the vehicle body 3 is provided in the middle of the lever 76, and the screw 90 is made to pass through the lever 76, a spring 91 is supported by the screw 90, and a screw 92 is screwed to the screw 90. A tensioner that adjusts the biasing force of the spring 91 to separate the first vertical shaft 77 from the input shaft 13 of the torque detector 14 is formed.

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 stage S6 of the input shaft 13 and the chain C3 surrounding the sixth chainwheel S6 constitute a third-stage transmission means P.

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 intermediate shaft 55, the second-stage transmission means P2, the joint shaft 94, and the third-stage transmission shaft P3. It can be transmitted to the input shaft 13 of the torque detector 14. The slack of the first chain C1 is set to an appropriate constant tension by the slide fitting 59, and the slack of the second chain C2 is set to an appropriate constant tension by the first bearing box 61.

The third link between the fifth chain wheel S5 and the input shaft 13
The tension is applied to the chain C3 by the coil spring 91. The impact when the rear wheel 5 reaches the steering end is first applied to the chain C3. The spring 91 absorbs and reduces the impact, and transmits the impact to the transmission device between the chain and the steering wheel 6. To prevent. The fifth chain wheel S5 swings by the action of the spring 91, but this movement is absorbed by the universal joint 94,
There is no adverse effect on the transmission, in particular on the second bearing housing.

[0043]

As described above, the device of the present invention reduces the impact force at the moment when the steering end is reached,
The elements of the mechanism for transmitting the steering torque, such as the bearings and the joints, can be reduced in size, and the steering wheel operation feeling can be well maintained even if there is an impact.

[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.

FIG. 10 is a perspective view illustrating a second bearing housing of a conventional transmission.

[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 (1)

(57) [Claims] 1. A vehicle body, a battery mounted at the center of the vehicle body and reaching the bottom of the vehicle body, a front wheel disposed on the vehicle body on both front sides of the battery, and a rear wheel disposed on the vehicle body at the rear center of the battery and not driven. A rear wheel steering shaft that supports the rear wheel at the rear of the vehicle body, a steering driver that has a motor and generates an auxiliary torque for turning the steering shaft, and is connected via a steering wheel transmission device at the front of the vehicle body. While a power steering device including a torque detector that detects a steering torque from the steering wheel acting on an input shaft is arranged, the transmission device is
First-stage transmission means for connecting a first chain at a lower end of a handlebar and a second chain at an upper end of an intermediate shaft vertically pivoted in front of the battery by a first chain, the intermediate shaft, and a lower end of the intermediate shaft; A second stage transmission means in which the third chain wheel of the first and second fourth chain wheels at the lower end of the first vertical shaft vertically supported by the battery are connected by a second chain passing below the battery;
A third-stage transmission means for connecting a fifth chain wheel at the upper end of a second vertical shaft supported vertically to the rear of the vehicle body with a sixth chain wheel attached to the input shaft by a third chain; A joint that connects the first and second vertical shafts via a universal joint, and a bearing that supports the upper end of the second vertical shaft is swingably supported via a lever provided on a vehicle body; A battery-type forklift, wherein the bearing is oscillated so as to apply tension to the third chain by interposing a spring between the lever and the vehicle body.