JP2010208448A - Steering angle detecting device of steer-by-wire type steering - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering angle detecting device with simple and inexpensive configuration accurately detecting the steering angle of a handle. <P>SOLUTION: The steering angle detecting device includes: a steering axis 10, directly coupled with the handle, and which, when a steering angle of the handle changes by an angle, axially rotates by the angle; a rotation angle detector 11, having a detection axis 12a disposed on the extension line of the steering axis 10, and which, when the detection axis 12a axially rotates, outputs electric signals in accordance with the rotation; and a transmission member 14a having a clip shape, sandwiching the steering axis 10 being fixed to the detection axis 12a, transmitting the axial rotation of the steering axis 10 to the detection axis 12a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a steering angle detection device that is provided in a steer-by-wire type steering and detects a steering angle of a steering wheel and outputs an electric signal corresponding to the steering angle.

  In recent years, steer-by-wire type steering, in which at least a part of the steering wheel operation amount is electrically transmitted to a steered wheel, instead of mechanically transmitting the steering wheel as it is, has come to be frequently used. According to this method, since it is not necessary to provide a mechanical link mechanism, cost and vehicle weight can be greatly reduced.

  FIG. 6 shows a walkie forklift as an example of a vehicle that employs steer-by-wire steering. The walkie forklift 1 includes a vehicle main body 4, a grip arm 2 provided at an upper portion of the vehicle main body 4, and a fork 3 for placing a load provided at a rear portion of the vehicle main body 4. As shown in this figure, when the worker W grasps the grip arm 2 and moves forward, the grip arm 2 that has stood up tilts forward. The wheels 5 are driven by a motor (not shown) according to the inclination (angle). Thereby, the operator W can carry a load easily without feeling much weight.

The grip arm 2 also serves as a handle that indicates the traveling direction. Specifically, when the worker W changes the traveling direction, the handle 2 (= grip arm 2) turns from the root, and the steering shaft 10 directly connected to the handle 2 also rotates. The shaft rotation angle of the steering shaft 10, that is, the steering angle θ _H of the handle 2 is detected by the potentiometer 11, and the potentiometer 11 outputs an appropriate electrical signal corresponding to the steering angle θ _H. And EPS motor 30 changes the angle of wheel 5 according to the electric signal.

That is, in the walkie forklift 1, the steering angle θ _H of the handle 2 is once converted into an electric signal. And the angle of the wheel 5 is changed based on the electrical signal.

  FIG. 7 is an exploded perspective view of a connecting portion between the steering shaft 10 and the potentiometer 11 (hereinafter, this portion is referred to as “steering angle detection device”). As shown in this figure, the steering shaft 10 has a prismatic shape. The potentiometer 11 has a potentiometer shaft 12 protruding from the upper surface thereof, and outputs an electric signal corresponding to the axial rotation angle of the potentiometer shaft 12.

  The steering shaft 10 and the potentiometer shaft 12 are connected by a transmission member 20 that is formed by bending a single metal plate into a U-shape. A shaft fixing hole 20b for inserting the steering shaft 10 is formed on the surface of the transmission member 20 on the steering shaft 10 side. A shaft fixing hole 20a for inserting the potentiometer shaft 12 is formed on the surface of the transmission member 20 on the potentiometer 11 side.

  FIG. 8 shows a front view (A) and a left side view (B) when the steering angle detection device is viewed from the front side of the walkie forklift 1. The potentiometer shaft 12 is fixed to the transmission member 20 by tightening the nut 13 after being inserted into the shaft fixing hole 20a. On the other hand, the steering shaft 10 is not fixed with a nut or the like in consideration of replacement of the handle 2 or ease of maintenance.

Eventually, in this steering angle detection device, the rotation of the steering shaft 10 is transmitted to the potentiometer shaft 12 by the transmission member 20. Then, the potentiometer 11, the axial rotation angle of the potentiometer shaft 12, i.e., detects the steering angle theta _H of the steering wheel 2, and outputs an electrical signal corresponding thereto. In addition, the thing of patent document 1 is known as a walkie forklift provided with steer-by-wire type steering.

JP 2003-171095 A

In order to obtain a linear steering feeling, the steering angle detection device is generally required to detect the steering angle θ _H with high accuracy. However, in the conventional steering angle detection device, the shaft rotation of the steering shaft 10 may not be transmitted to the potentiometer shaft 12 on a one-to-one basis due to the dimensional deviation of the steering shaft 10 and / or the shaft fixing hole 20b. Further, in order to prevent the dimensional deviation, it is necessary to increase the processing accuracy of both members, which requires labor and cost for processing and dimensional management.

  Accordingly, an object of the present invention is to provide a steering angle detection device that can detect the steering angle of a steering wheel with high accuracy with a simple and inexpensive configuration.

  In order to solve the above problems, a steering angle detection device according to the present invention is a steering angle detection device that detects a steering angle of a steering wheel and outputs an electrical signal corresponding to the steering angle, and is directly connected to the steering wheel. Rotation that has a steering shaft that rotates by the angle when the steering angle changes, and a detection shaft that is arranged in an extension line of the steering shaft, and outputs an electrical signal in response to the detection shaft rotating An angle detector and a transmission member that has a clip shape, sandwiches one of the steering shaft and the detection shaft, is fixed to the other shaft, and transmits shaft rotation of the steering shaft to the detection shaft And.

  According to this configuration, since one of the steering shaft and the detection shaft is sandwiched by the transmission member having the clip shape, the shaft of the steering shaft can be obtained even if the processing accuracy of each member is somewhat poor. The rotation can be transmitted to the rotation angle detector (potentiometer) side with high accuracy.

  Specifically, the one shaft and the transmission member may be configured as follows. That is, the one shaft has at least a pair of parallel surfaces along an axial center line, and the connecting member includes a base portion having a shaft fixing hole for engaging with the other shaft, and the base A pair of clip portions extending across the one shaft from opposite ends of the material portion, and each tip portion of the clip portion is urged in a direction approaching each other and disposed between the tip portions. The one axis may be held between the parallel surfaces.

  Moreover, it is preferable that the said connection member bends one metal plate.

  The shape of the shaft fixing hole and the cross-sectional shape of the other shaft are preferably shapes other than a perfect circle.

  ADVANTAGE OF THE INVENTION According to this invention, the steering angle detection apparatus which can detect the steering angle of a steering wheel with high precision with a simple and cheap structure can be provided.

1 is an exploded perspective view of a steering angle detection device according to Embodiment 1. FIG. It is a figure which shows the assembly process of the steering angle detection apparatus which concerns on Example 1. FIG. It is a figure of the steering angle detection apparatus which concerns on Example 1, Comprising: (A) is the front view seen from the front side of the walkie forklift, (B) is the left view of (A). FIG. 5 is a diagram of a steering angle detection device according to a second embodiment, where (A) is an exploded perspective view and (B) is an enlarged view showing a shape of a shaft fixing hole. It is a disassembled perspective view of the steering angle detection apparatus which concerns on a modification. It is a figure which shows the use condition of a walkie forklift. It is a disassembled perspective view of the conventional steering angle detection apparatus. It is a figure of the conventional steering angle detection apparatus, Comprising: (A) is the front view seen from the front side of the walkie forklift, (B) is the left view of (A).

  Hereinafter, preferred embodiments of a steering angle detection device according to the present invention will be described with reference to the accompanying drawings. In each embodiment, it is assumed that the steering angle detection device is provided in the steer-by-wire type steering of the walkie forklift.

  FIG. 1 shows a steering angle detection apparatus according to the first embodiment. In this embodiment, the steering shaft 10 is a prismatic member having at least a pair of parallel surfaces 10a and 10b. The potentiometer 11 (corresponding to the “rotation angle detector” of the present invention) has a potentiometer shaft 12a (corresponding to the “detection shaft” of the present invention) protruding from its upper surface, and corresponds to the rotational angle of the potentiometer shaft 12a. Outputs electrical signals.

  A screw thread (groove) is formed in the potentiometer shaft 12a so that it can be screwed into a nut described later. The potentiometer shaft 12a is disposed on an extension line of the steering shaft 10 so that the rotation shaft of the steering shaft 10 and the rotation shaft of the potentiometer shaft 12a coincide with each other.

  The transmission member 14a is formed by bending a single metal plate and has a clip shape as a whole. More specifically, the transmission member 14a includes a base member 16 having a shaft fixing hole 15a for inserting the potentiometer shaft 12a, and a pair of base members 16 extending from opposite ends of the base member 16 with the steering shaft 10 interposed therebetween. It consists of clip portions 17 and 18.

  As shown in FIG. 2, the tip portions of the clip portions 17 and 18 are urged toward each other, and when the steering shaft 10 is inserted between the clip portions 17 and 18, the parallel surfaces 10 a and 10 b. Thus, the clip portions 17 and 18 are pushed and expanded. That is, the steering shaft 10 is clamped by the urging force of the clip portions 17 and 18. Moreover, since the steering shaft 10 has the parallel surfaces 10a and 10b, the steering shaft 10 does not idle with respect to the transmission member 14a.

  FIG. 3 is a front view (A) and a left side view (B) when the steering angle detection device according to the present embodiment is viewed from the front side of the walkie forklift. As described above, the steering shaft 10 is sandwiched between the clip portions 17 and 18. On the other hand, after the potentiometer shaft 12a is inserted into the shaft fixing hole 15a, the potentiometer shaft 12a is fixed to the base member 16 of the transmission member 14a by the nut 13.

  As described above, in the steering angle detection device according to the present embodiment, the steering shaft 10 is clamped by the urging force of the clip portions 17 and 18, so that the steering shaft 10 can rotate or rotate even if the processing accuracy is somewhat poor. The axis will not shift. Therefore, according to the steering angle detection device according to the present embodiment, the shaft rotation of the steering shaft 10 can be accurately transmitted to the potentiometer shaft 12a, and the steering angle of the steering wheel can be detected with high accuracy.

  Moreover, in the steering angle detection device according to the present embodiment, the transmission member 14a can be easily and inexpensively made from one metal plate.

  Further, as described above, according to the steering angle detection device according to the present embodiment, the positional deviation between the steering shaft 10 and the transmission member 14a is prevented. Therefore, it is possible to prevent the potentiometer 11 from being damaged by applying an excessive force to the potentiometer shaft 12a due to the displacement of the transmission member 14a with respect to the steering shaft 10.

  Since the potentiometer 11 is a sensor, when the potentiometer shaft 12a is rotated through the transmission mechanism 14a, no reaction force is generated at the connection portion between the steering shaft 10 and the transmission mechanism 14a, that is, the clip portion. Therefore, even with a simple configuration in which the steering shaft 10 is simply sandwiched between the clip portions 17 and 18, no positional deviation occurs between the steering shaft 10 and the transmission mechanism 14a.

  Next, a steering angle detection apparatus according to the second embodiment will be described with reference to FIG. The steering angle detection device according to the present embodiment and the steering angle detection device according to Embodiment 1 (see FIG. 1) are different in the cross-sectional shape of the potentiometer shaft and the shape of the shaft fixing hole. That is, in the steering angle detection device according to the first embodiment, the cross-sectional shape of the potentiometer shaft 12a and the shape of the shaft fixing hole 15a are both round, but in the steering angle detection device according to the present embodiment, the potentiometer shaft 12b. The cross-sectional shape and the shape of the shaft fixing hole 15b are the same shape other than a perfect circle (see FIG. 4B).

  Due to this difference, the steering angle detection device according to the present embodiment makes it difficult for the potentiometer shaft 12b to idle with respect to the transmission member 14b, and the steering angle of the steering wheel can be detected with higher accuracy. Also, the zero point adjustment of the potentiometer 11, that is, the steering angle 0 ° of the steering wheel can be easily associated with the shaft rotation angle 0 ° of the potentiometer shaft 12b.

The preferred embodiments of the steering angle detection device according to the present invention have been described above, but the present invention is not limited to these configurations.
For example, the steering shaft is not limited to a prismatic shape, and may have an arbitrary shape that does not idle with respect to the clip portion. Moreover, the constriction of the front-end | tip part of a clip part can be abbreviate | omitted.

  Further, as shown in FIG. 5, the transmission member 14 a may be used upside down with respect to the first embodiment, and the potentiometer shaft 12 c may be clamped by the urging force of the clip portions 17 and 18. However, in this case, it is necessary to appropriately change the shapes of the potentiometer shaft 12c and the steering shaft 10c.

1 Walky forklift 2 Grip arm (handle)
3 Fork 4 Vehicle body 5 Wheel 10 Steering shaft 11 Potentiometer (rotation angle detector)
12 Potentiometer axis (detection axis)
13 Nut 14 Transmission member 15 Shaft fixing hole 16 Base part 17 Clip part 18 Clip part 30 EPS motor

Claims (4)

A steering angle detection device that detects a steering angle of a steering wheel and outputs an electrical signal corresponding to the steering angle,
A steering shaft that is directly connected to the steering wheel and that rotates when the steering angle changes;
A rotation angle detector that has a detection shaft arranged in an extension line of the steering shaft, and outputs an electrical signal corresponding to the detection shaft rotating;
A transmission member that has a clip shape, sandwiches one of the steering shaft and the detection shaft and is fixed to the other shaft, and transmits the rotation of the steering shaft to the detection shaft;
A steering angle detection device comprising: The one axis has at least a pair of parallel surfaces along the axis center line,
The connecting member includes a base member having a shaft fixing hole for engaging with the other shaft, and a pair of clip portions extending across the one shaft from opposite ends of the base member. Become
2. The steering according to claim 1, wherein each tip portion of the clip portion is biased in a direction in which the tip portions approach each other, and the one shaft disposed between the tip portions is sandwiched between the parallel surfaces. Angle detection device.   The steering angle detection device according to claim 1, wherein the connecting member is formed by bending a single metal plate.   The steering angle detection device according to claim 2, wherein the shape of the shaft fixing hole and the cross-sectional shape of the other shaft are shapes other than a perfect circle.

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