JP2010120465A - Steering angle detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the installation space from requiring a large space and to improve detection accuracy of a steering angle in a steering angle detection device applied to a cargo handling vehicle such as a forklift and used for detection of a steering angle of a steering wheel. <P>SOLUTION: The steering angle detection device includes a support member 2, a king pin 3, a cam 4, and a linear position detection sensor 5. The cam 4 is coaxially arranged in the upper part of the king pin 3, and the linear position detection sensor 5 including an input shaft 24 abutting upon a peripheral surface 23 of the cam 4 and linearly moved and a return spring returning it to an original position at all time is attached to the support member 2. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an improvement in a steering angle detection device that is applied to a cargo handling vehicle such as a forklift and used to detect the steering angle of a steering wheel.

  Conventionally, as this type of steering angle detection device, for example, as described in Patent Documents 1 to 6, a device in which a rotation sensor is disposed above a king pin is known.

JP-A-10-310077 Japanese Patent Laid-Open No. 11-5555 (Japanese Patent No. 3574854) Japanese Patent Laid-Open No. 11-23207 (Japanese Patent No. 3175645) JP 2004-106564 A JP 2004-354355 A (Patent No. 3999702) JP 2007-78554 A

However, such a device has a problem in that the installation space is bulky and obstructive because the rotation sensor is disposed so as to protrude greatly above the king pin.
In addition, since the input shaft of the rotation sensor and the king pin are basically connected by the fitting of the unevenness, the detection accuracy of the steering angle is improved unless the fitting accuracy of both the unevenness is increased. I could n’t. In particular, in the case of using an elastic member, this is remarkable because it deforms or deteriorates with time.

  The present invention has been devised in view of the above-mentioned problems, and has been devised to solve this problem. The problem is that the installation space is not bulky and the steering angle detection accuracy is improved. It is in providing an angle detection device.

  The steering angle detection device according to the present invention basically corresponds to a support member, a king pin rotatably provided on the support member, a cam coaxially provided on the top of the king pin, and a peripheral surface of the cam. It is characterized in that it is constituted by an input shaft that is linearly moved and a return position spring that always returns the input shaft to its original position and is attached to a support member.

  The king pin is rotatably supported by the support member, and the linear position detection sensor is attached to the support member. The input shaft of the linear position detection sensor is always in contact with the circumferential surface of the cam by a return spring. Therefore, the rotation of the king pin is transmitted as a linear motion to the input shaft of the linear position detection sensor via the cam, and the steering angle of the steered wheels can be detected by the linear position detection sensor.

Since the rotation of the king pin is converted into a linear motion using a cam and transmitted to the input shaft of the linear position detection sensor, the linear position detection sensor can be arranged on the side rather than above the king pin. As a result, the installation space is not bulky and does not get in the way.
Since the return shaft of the linear position detection sensor is used to always engage the input shaft with the cam, the dedicated return means can be omitted, and the structure can be simplified and the cost can be reduced accordingly.
Since only the cam is provided on the upper part of the king pin, the grease vertical hole can be easily drilled, and the greasing structure can be simplified accordingly.
The input shaft of the linear position detection sensor and the king pin are linked together by engaging the input shaft of the linear position detection sensor with the peripheral surface of the cam via the cam, so only the peripheral surface of the cam (cam surface) It is possible to improve the detection accuracy of the steering angle only by increasing the machining accuracy.

  The cam is preferably integrally formed by cutting the upper part of the king pin. In this way, the number of parts is reduced, so that assembly and structure can be simplified accordingly.

  The linear position detection sensor is preferably a linear potentiometer having a return spring that always returns the input shaft to the original position. In this way, a commercially available linear potentiometer can be used as it is, and the cost can be reduced accordingly.

According to the present invention, the following excellent effects can be achieved.
(1) A support member, a king pin, a cam, and a linear position detection sensor are used. In particular, a cam is provided coaxially on the upper part of the king pin, and an input shaft that is linearly moved in contact with the peripheral surface of the cam. Since the linear position detection sensor including the return spring that always returns to the original position is attached to the support member, the installation space is not bulky and the detection accuracy of the steering angle can be improved.
(2) A linear position detection sensor provided with a cam coaxially on the top of the king pin, and having an input shaft that is linearly moved in contact with the peripheral surface of the cam, and a return spring that always returns the shaft to its original position. Since it is attached to the support member, a grease vertical hole can be drilled from the upper surface of the kingpin or cam, and the greasing structure can be simplified.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal side view of the steering angle detection device of the present invention with the lower half omitted. FIG. 2 is a plan view of the main part of FIG. FIG. 3 is a view similar to FIG. 2 showing a state of steering in one direction. FIG. 4 is a view similar to FIG. 2 showing a state of steering in the other direction.

  The steering angle detection device 1 includes a support member 2, a king pin 3, a cam 4, and a linear position detection sensor 5.

The support member 2 forms a basic part of the steering angle detection device 1, and is a rear axle of a forklift in this example.
The rear axle 2 has a box shape, and includes upper and lower horizontal plates 6, appropriate vertical plates 7 connecting them, and upper and lower bosses (lower portions) provided at both ends of the upper and lower horizontal plates 6 and having a cylindrical shape. 8 is omitted).

The king pin 3 is rotatably provided on the support member 2. In this example, the king pin 3 has a cylindrical shape, and needle bearings (the lower one is not shown) 9 are provided on the upper and lower bosses 8 of the support member 2. Is supported so as to be rotatable around the vertical axis.
A bracket 10 having a substantially L shape is detachably provided on the upper surface of the upper boss 8. An O-ring or the like is provided between the horizontal piece of the bracket 10, the upper boss 8, the needle bearing 9, and the king pin 3. The sealing material 11 is interposed.
A knuckle 12 is inserted and fixed to the king pin 3 so as to prevent rotation, and a thrust bearing 13 is interposed between the knuckle 12 and the upper boss 8 of the support member 2.
A horizontal axle 14 formed on the knuckle 12 is provided with a hub 16 that can rotate about a horizontal axis via a plurality of bearings 15. The hub 16 is provided with a steering wheel 17 composed of a rim, a tire and the like so as to be detachable.

  The king pin 3 is provided with an upper and lower greasing structure. The upper greasing structure includes a grease vertical hole 18 drilled in the axial direction from the upper surface of the cam 4 integral with the king pin 3 to a predetermined depth, an obturator 19 for closing the upper part, and a needle perpendicular to the grease vertical hole 18. An appropriate number of grease horizontal holes 20 communicating with the bearing 9 and the thrust bearing 13, a supply hole 21 drilled in the knuckle 12 and communicating with the lower grease horizontal hole 20, and a grease nipple 22 provided on the outside thereof I have. Although the lower greasing structure is omitted, it is the same as the conventional one (see, for example, Patent Document 1).

The cam 4 is provided coaxially on the upper portion of the kingpin 3. In this example, the upper portion of the kingpin 3 is cut and formed integrally.
The cam 4 protrudes above the upper surface of the upper boss 8 of the support member 2 and penetrates the horizontal piece of the bracket 10 to be rotatable.
The peripheral surface (cam surface) 23 of the cam 4 has a substantially flat egg shape, and its shape is devised so as to convert the rotational motion of the kingpin 3 into a linear motion with high accuracy.

The linear position detection sensor 5 includes an input shaft 24 that is engaged with the peripheral surface 23 of the cam 4 and linearly moves, and a return spring (not shown) that always returns the shaft to its original position, and is attached to the support member 2. In this example, a linear potentiometer having a return spring that always returns the input shaft 24 to the original position is used, and a commercially available one is used.
In addition to the input shaft 24 and the return spring, the linear position detection sensor 5 includes a main body 25 and an attachment portion 26 that support them, and the attachment portion 26 is detachably attached to the vertical piece of the bracket 10. .
Thus, the upper boss 8 of the support member 2 is detachably provided with a cover 27 that covers the cam 4 and the linear position detection sensor 5.

Next, the operation will be described based on such a configuration.
The king pin 3 is supported by the support member 2 via the needle bearing 9 and the thrust door ring 13 so as to be rotatable about the vertical axis, and the linear position detection sensor 5 is attached to the support member 2. The input shaft 24 of the linear position detection sensor 5 is always in contact with the peripheral surface 23 of the cam 4 depending on the elasticity of the return spring.
As shown in FIGS. 2 to 4, when the steering wheel 17 including the knuckle 12 and the like is steered, the kingpin 3 is also rotated in the same direction. Then, the rotation of the king pin 3 is transmitted as a linear motion to the input shaft 24 of the linear position detection sensor 5 via the cam 4, and the steering angle of the steering wheel 17 can be detected by the linear position detection sensor 5.

  Since the cam 4 is used to convert the rotation of the king pin 3 into a linear motion and transmitted to the input shaft 24 of the linear position detection sensor 5, the linear position detection sensor 5 is disposed not on the king pin 3 but on the side. I can do it. That is, the cam 4 is disposed above the kingpin 3, and the linear position detection sensor 5 is disposed on the side of the cam 4. As a result, the installation space is not bulky and does not get in the way.

  Since the return shaft of the linear position detection sensor 5 is used to always engage the input shaft 24 with the cam 4, a dedicated return means can be omitted, and the structure can be simplified and the cost can be reduced accordingly. .

  Since only the cam 4 is provided on the upper part of the king pin 3, the grease vertical hole 18 can be easily drilled, and the greasing structure can be simplified accordingly.

  Since the input shaft 24 of the linear position detection sensor 5 and the king pin 3 are linked by engaging the input shaft 24 of the linear position detection sensor 5 with the peripheral surface 23 of the cam 4 via the cam 4, the cam 4 It is possible to improve the detection accuracy of the steering angle only by increasing the processing accuracy of only the peripheral surface 23.

In the above example, the cam 4 is integrally formed by cutting the upper portion of the king pin 3. However, the cam 4 is not limited to this and is fixed separately to the upper end of the king pin 3 by welding or the like. Or may be detachably attached with a bolt or the like. When the cam 4 is detachably attached, the cam 4 may also be used as an obturator 19 that closes the grease vertical hole 18. In this way, the number of parts can be reduced, so that the structure can be simplified and the cost can be reduced.
In the previous example, the linear position detection sensor 5 is a linear potentiometer. However, the linear position detection sensor 5 is not limited to this, and may be a linear encoder, for example.

The vertical side view which abbreviate | omitted the lower half which shows the steering angle detection apparatus of this invention. The principal part top view of FIG. The same figure as FIG. 2 which shows the state steered to one direction. The same figure as FIG. 2 which shows the state steered to the other direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steering angle detection apparatus, 2 ... Support member, 3 ... King pin, 4 ... Cam, 5 ... Linear position detection sensor, 6 ... Horizontal plate, 7 ... Vertical plate, 8 ... Boss, 9 ... Needle bearing, 10 ... Bracket, DESCRIPTION OF SYMBOLS 11 ... Sealing material, 12 ... Knuckle, 13 ... Thrust bearing, 14 ... Axle, 15 ... Bearing, 16 ... Hub, 17 ... Steering wheel, 18 ... Grease vertical hole, 19 ... Obturator, 20 ... Grease horizontal hole, 21 ... Supply hole , 22 ... grease nipple, 23 ... peripheral surface, 24 ... input shaft, 25 ... main body, 26 ... mounting portion, 27 ... cover.

Claims (3)

  A support member, a king pin rotatably provided on the support member, a cam coaxially provided on the upper portion of the king pin, an input shaft that is linearly moved in contact with the peripheral surface of the cam, and is always in the original position. A steering angle detection device comprising: a linear position detection sensor that is attached to a support member and includes a return spring that returns to a position.   The steering angle detection device according to claim 1, wherein the cam is integrally formed by cutting an upper portion of the king pin.   The steering angle detection device according to claim 1, wherein the linear position detection sensor is a linear potentiometer including a return spring that always returns the input shaft to the original position.

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