JPH10194693A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb a shock generated in a steering system in a steering end. SOLUTION: In a steering device, a steering action (steering force) based on a steering wheel 3 is transmitted to a rear wheel 5 via a chain 12 wound on a drive sprocket 9 and a driven sprocket 11. In this process, the chain 12 is pressed inward so as to take a substantially L-shape by means of a pair of intermediate sprockets 15 connected together by means of a rod 16, and as a result, predetermined tension is applied. The rod 16 is supported movably in the axial direction (direction crossing the chain 12) by means of a rod receiver 17, and in the steering end, the intermediate sprockets 15 are displaced so that tension on the tensed side of the chain 12 is equalized to that on the loosened side, and consequently, a shock can be absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device used for a battery-powered forklift, for example.
More specifically, the present invention relates to a technique for absorbing a shock at a steering end.

[0002]

2. Description of the Related Art Generally, a forklift is a rear-wheel steering type, and a steering device used for the forklift is a gear box operated by a steering wheel;
There is a type in which a chain transmission device is provided between the rear wheel and a rear wheel, and a steering operation (steering force) by a steering wheel is transmitted to the rear wheels via a chain.

[0003]

In a steering apparatus of the type described above, the maximum steering angle of the rear wheels is regulated by a mechanical stopper, so that the impact at the steering end is directly applied to a chain, sprocket, gear, or the like. Will be transmitted to. Therefore, when designing the components of the steering system, it is necessary to secure a large strength that can withstand the impact, which is an obstacle to downsizing or cost reduction of the steering device.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a steering device capable of absorbing an impact generated in a steering system at a steering end.

[0005]

Means for Solving the Problems In order to solve the above problems, the present invention is configured as follows. That is, the invention of claim 1 is a steering device of a type in which steering operation by a steering wheel is transmitted to steered wheels via a wrapping transmission device, and is always in a lateral direction with respect to a rope member in the wrapping transmission device. A shock absorber that is held at a position where a predetermined tension is applied by pressing from above and that absorbs an impact by moving in a direction that gives a slack to the rope member when a tension exceeding the predetermined tension acts on the rope member. It is characterized by having. Here, the winding transmission device is a device that transmits rotation by winding a bendable rope member such as a chain, a wire, or a belt around a vehicle such as a sprocket or a pulley provided on a driving shaft and a driven shaft.

According to the first aspect of the present invention, when excessive tension acts on the rope member at the steering end, the shock absorbing device moves in a direction in which the rope member is slackened, so that the steering system is moved. Can be absorbed. For this reason, it is possible to secure the necessary strength of the components of the steering system, such as gears, chains, sprockets, shafts, etc., and to reduce the size and cost of the components.

According to a second aspect of the present invention, in the steering device according to the first aspect, the buffering device includes a pair of pressing members for applying tension by applying pressure from a lateral direction to a parallel portion of the cable member, and a pair of pressing members. And a connecting member connected to the pressing member and movably supported together with the pressing member in a direction crossing the cable member in response to a change in tension of the cable member.

Therefore, according to the second aspect of the present invention, when excessive tension acts on the cable member at the steering end, the side pulled by the motor vehicle (hereinafter, referred to as a tension side).
One of the pressurizing members is pushed and displaced by the tension acting on the rope member, and at the same time, the other pressurizing member is displaced in the same direction and tension is applied to the rope member on the side sent out from the motor vehicle (hereinafter referred to as the slack side). Add. That is, the shock generated in the steering system can be absorbed by the pair of pressure members being displaced so that the tension acting on the rope member on the tension side and the tension acting on the rope member on the slack side become equal. Such an absorption system has a simple structure and does not cause slack in the rope member, so that there is no problem that the rope member comes off the driving vehicle or the driven vehicle.

According to a third aspect of the present invention, in the steering device according to the first aspect, the buffering device includes a pair of pressing members for applying tension by pressing a parallel portion of the cable member from a lateral direction, and a pair of pressing members. A connecting member movably connected in a direction traversing the cable member and a connecting member movably supported in a direction traversing the cable member, and a biasing member for urging the both pressing members in a direction of pressing the cable member. And an elastic member.

Therefore, according to the third aspect of the present invention, when excessive tension acts on the rope member at the steering end, one of the pressure members is pushed and displaced by the tension acting on the tension-side rope member. The elastic member is elastically deformed. That is, since the shock generated in the steering system due to the elastic deformation of the elastic member can be absorbed, softer shock absorption becomes possible. Further, the pressing force applied to one pressing member is transmitted as a force to move the other pressing member in the same direction via the elastic member and the connecting member. For this reason, tension is also applied to the cable member on the slack side, and in this case, the problem that the cable member comes off the prime mover or the driven vehicle does not occur.

According to a fourth aspect of the present invention, there is provided a steering device for a battery-powered forklift, wherein a cable member of a wrapping transmission device for transmitting a steering force to a rear wheel is disposed through an upper portion of the battery storage chamber. A pair of pressure members for applying tension by applying inward pressure to parallel portions of the cable member is provided, and both pressure members are connected by a connection member movable in a direction crossing the cable member. And

Therefore, according to the fourth aspect of the invention, similarly to the second aspect of the invention, the shock of the steering system at the steering end can be absorbed, and the tension is always applied to the slack side of the cable member. Since the state is maintained, the space utilization efficiency in the battery storage room can be improved, and interference with the battery case in the battery storage room or a wire harness, a hydraulic hose, or the like located in the vicinity thereof can be avoided.

[0013]

Embodiments of the present invention will be specifically described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 shows an entire battery-powered forklift to which a steering device according to the present embodiment is applied. As shown in the figure, a driver's seat 2 is provided at an upper portion of a machine frame 1, and a steering wheel 3 is disposed in front of the driver's seat 2. A counterweight 4 is mounted on a rear portion of the machine frame 1, and a rear wheel 5 as a steered wheel is attached to the counterweight 4.

FIG. 2 is a side view of the steering device mounted on the forklift, and FIG. 3 is a perspective view of the steering device. As shown in FIG. 2, a battery storage room 6 is provided at the center of the machine base 1, and the battery storage room 6 is provided.
Stores a battery case (not shown) containing a battery.

A gear box 7 having a plurality of gear trains 7a forming a part of a steering system is attached to an upper portion of a front cross plate 6a of the battery storage room 6. The gear box 7 is provided on an input side of the gear train 7a. A steering shaft 8 operated by the steering wheel 3 is connected, and a drive sprocket 9 as a motor vehicle is mounted on the output side.

On the other hand, a steering shaft 10 for steering the rear wheel 5 is mounted on a mounting boss 4a of the counterweight 4 so as to be rotatable around a vertical axis, and a driven sprocket 11 as a driven vehicle is provided at an upper end thereof. Installed.
An endless chain 12 as a rope member is wound around the driving sprocket 9 and the driven sprocket 11 in parallel. Thus, the driving sprocket 9,
A driven transmission is constituted by the driven sprocket 11 and the chain 12, and a steering force generated by rotating the steering wheel 3 is transmitted to the rear wheel 5 via the gear box 7 and the transmitted transmission.

As shown in FIG. 3, the driven sprocket 11
Has a stopper 1 for regulating the steering end.
3 is provided, and this stopper 13 is
The maximum turning angle of the rear wheel 5 is restricted by abutting on the right rotation restricting stopper receiver 14a or the left turning restriction stopper receiver 14b fixed to the side.

The stopper 13 is connected to the stopper receiver 14
When the steering system is strongly contacted with the stopper a or the stopper receiver 14b, an impact is generated in the steering system. Therefore, a shock absorbing device for absorbing the impact at the steering end is provided. The shock absorber according to the present embodiment includes the chain 1
The main member is an intermediate sprocket 15 as an impact-absorbing pressurizing member that constantly applies a constant tension to the second sprocket.

That is, as shown in FIG. 3, a pair of intermediate sprockets 15 for pressing the chain 12 inward are arranged outside the parallel portions of the chain 12 near the driven sprocket 11, respectively. 12 is pressed so as to form a substantially rectangular shape. A support shaft 15a rotatably supporting the intermediate sprocket 15 is connected by a rod 16 as a connecting member extending horizontally in a direction crossing the chain 12, and the rod 16 is supported by a rod receiver 17 fixed to the counterweight 4. It is movably supported in the direction, that is, in the direction crossing the chain 12.

According to the present embodiment configured as described above, when an impact occurs on the steering system at the steering end, the pair of intermediate sprockets 15 absorbs excessive tension acting on the tight side of the chain 12. Work like that. This will be described with reference to FIG. FIG. 4A shows a neutral state where the steering operation is not performed, and in this case, both the intermediate sprockets 15 are connected to the chain 1.
2 are pressed with an equal force. (B) shows the time of steering operation. At this time, the tension on the tension side (upper side in the figure) of the chain 12 is larger than the tension on the slack side, so that the intermediate sprocket 15 connected by the rod 16 is The side where the tension on the tension side and the tension on the slack side are equal,
That is, it is moved to the tension side.

(C) shows a steering end. The stopper 13 has one stopper receiver 14a or 14
When an impact is generated by contact with the chain b, an excessive tension acts on the tension side (upper side in the figure) of the chain 12 due to the impact. At this time, the intermediate sprocket 15 bends inwardly into a V shape. The intermediate sprocket 15 is moved outward so that the tight side of the chain 12 is straightened, and the corresponding intermediate sprocket 15 is moved inward so as to increase the degree of bending on the slack side of the chain 12. . That is, the intermediate sprocket 15 absorbs excessive tension acting on the chain 12 by moving the chain 12 so that the tension on the tension side and the tension on the slack side are equal, and the impact is transmitted to the gear box 7 via the chain 12. To prevent

As described above, according to the present embodiment, since the shock generated in the steering system at the steering end can be absorbed, the necessary strength of the components such as the gear box 7, the chain 12, the sprockets 9, 11 in the steering system is required. And the size and cost of the components can be reduced. In addition, the impact input to the driver's hand is reduced, and discomfort is eliminated.

Further, the shock absorber according to the present embodiment has a simple structure and does not cause any slack in the chain 12, so that the problem that the chain 12 comes off from the sprockets 9 and 11 is solved. Moreover, in the case of a battery type forklift, since the chain 12 is disposed above the battery storage chamber 6, not only the battery case but also a wire harness and hydraulic equipment around the machine base are provided around the chain 12. Although there is a hydraulic hose or the like to be connected, according to the present embodiment, since the chain 12 is bent inward and is not slackened, the interference of the chain 12 with the above-described peripheral components is prevented. This can be prevented beforehand, and the space utilization efficiency of the battery storage room 6 can be improved.

Next, a second embodiment will be described with reference to FIG. In the first embodiment described above, a chain transmission system is adopted as the wrapping transmission device for transmitting the rotation of the gear box 7 to the steering shaft 10, but in the second embodiment, the V belt transmission is used. In other words, a V-belt 20 as a cable member is wound around a driving pulley 18 provided on the output side of a gear box (not shown) and a driven pulley 19 provided on the steering shaft 10. A pair of intermediate pulleys 21 as a pressure member for absorbing shock are pressed against the belt 20 from the outside.

The other structures, such as the structure in which the intermediate pulley 21 is connected by the rod 16 and the structure in which the rod 16 is movably supported in the direction crossing the V-belt 20 by the rod receiver 17, are the same as those in the first embodiment. Same as the form. Therefore, in the case of the second embodiment, the same operation and effect as those of the first embodiment can be obtained.

Next, a third embodiment will be described with reference to FIGS. In this embodiment, a part of the shock absorber according to the first embodiment is modified. As shown, a pair of intermediate sprockets 2 for shock absorption
The support shaft 22a of one of the intermediate sprockets 22 is fixed to one end of a rod 24 as a connecting member, and the support shaft 23a of the other intermediate sprocket 23 is slidably fitted to the rod 24. .

A compression coil spring 25 as an elastic member for absorbing shock is attached to the rod 24.
One end of the compression coil spring 25 is in contact with the support shaft 23 a of the movable intermediate sprocket 23, and the other end of the compression coil spring 25 is adjustable by a nut 27 screwed into a threaded portion formed on the other end of the rod 24. And the direction in which the two intermediate sprockets 22 and 23 approach each other, ie, the chain 1
A spring force is applied in a direction to press inwardly and to bend into a dogleg shape. Note that the other components are configured in the same manner as in the first embodiment, and therefore the same reference numerals are given and the description thereof is omitted.

Therefore, according to this embodiment, when excessive tension is generated on the tight side of the chain 12 at the steering end, one of the intermediate sprockets 22
(Or 23) moves outward while compressively deforming the compression coil spring 25, and absorbs excessive tension of the chain 12.
On the other hand, the opposite intermediate sprocket 23 (or 22) moves inward via the compression coil spring 25, and the chain 12
Apply tension to the slack side of. Thus, according to this embodiment, the impact at the steering end can be softly absorbed by the elastic deformation of the compression coil spring 25, and the problem of the slack of the chain 12 is solved.

Next, a fourth embodiment will be described with reference to FIG. In this embodiment, the rod 16 as the connecting member in the above-described first embodiment is changed to a swing type V-arm 28. The V-shaped arm 28 is horizontally rotatably mounted via a pin 30 to an arm receiver 29 as a support member having a bent portion fixed to a counter weight (not shown). A pair of pressurizing intermediate sprockets 15 is provided. Other configurations are the same as those of the first embodiment. Therefore, according to this embodiment,
Except that the movement of the intermediate sprocket 15 is an arc movement about the pin 30 as the rotation center, the same operation and effect as in the first embodiment can be obtained.

Various modifications can be made to the embodiment described above. For example, the pressing direction of the chain 12 or the belt 20 by the intermediate sprocket 15 or the intermediate pulley 21 as the pressing member may be changed from inward to outward. In addition, the rotary member has the advantage that the rotary member has less wear, but the shock absorbing effect can be enjoyed even with the non-rotary member. In addition, although the description has been given of the forklift for rear wheel steering, the present invention is not limited to the rear wheel steering or forklift, and any steering device including a wrapping transmission device can be applied.

[0031]

As described in detail above, according to the present invention,
The shock generated at the steering system at the end of the steering is absorbed, and the components of the steering system can be reduced in size and cost.

[Brief description of the drawings]

FIG. 1 is a side view showing an entire battery-powered forklift.

FIG. 2 is a side view of the steering device mounted on the forklift.

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

4A and 4B are explanatory diagrams of a steering operation, wherein FIG. 4A shows a neutral state, FIG. 4B shows a steering operation state,
(C) shows the state at the time of steering end.

FIG. 5 is an explanatory diagram showing a steering device according to a second embodiment.

FIG. 6 is an explanatory diagram showing a steering device according to a third embodiment.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

FIG. 8 is an explanatory diagram showing a steering device according to a fourth embodiment.

[Explanation of symbols]

 Reference Signs List 3 steering wheel 5 rear wheel 7 gear box 9 driving sprocket 10 steering shaft 11 driven sprocket 12 chain 15 intermediate sprocket 16 rod 17 rod receiver

Claims (4)

[Claims] 1. A steering device for transmitting steering operation by a steering wheel to a steered wheel via a winding transmission, wherein a pressure is always applied to a rope member of the winding transmission from a lateral direction. A steering device having a shock absorber that is held at a position where a predetermined tension is applied and absorbs an impact by moving in a direction in which the rope member is slackened when a tension exceeding the predetermined tension acts on the rope member. . 2. The steering device according to claim 1, wherein the shock-absorbing device connects a pair of pressurizing members for applying tension by pressing laterally the parallel portions of the cable members and applying a tension between the pair of pressurizing members. And a connecting member movably supported together with a pressure member in a direction crossing the cable member in response to a change in tension of the cable member. 3. The steering device according to claim 1, wherein the buffering device includes a pair of pressing members for applying a tension by laterally pressing a parallel portion of the cable member and a cable between the two pressing members. A connecting member that is connected so as to be relatively movable in a direction crossing the member and is supported so as to be movable in a direction crossing the cable member, and an elastic member that urges both the pressing members in a direction of pressing the cable member against the cable member. Steering device. 4. A steering device for a battery-powered forklift, wherein a cable member of a wrapping transmission device for transmitting a steering force to a rear wheel is disposed through an upper part of a battery storage chamber, and is parallel to the cable member. It has a pair of pressure members that apply tension inward by pressing inward at the site,
A steering device in which the two pressing members are connected by a connecting member movable in a direction crossing the cable member.