JP2008082875A - Mounting structure for rotation type sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation type sensor mounting structure capable of ensuring sufficient reliability of a sensor by simplifying the structure to facilitate assembling, while ensuring detection precision of the sensor, and preventing an excessive load from being applied to the sensor. <P>SOLUTION: A lift arm 7 has spring pins 25, 25 at two points in a region different from the axis of rotation of the lift arm 7, and an angle sensor 23 has a detecting shaft 23a urged by a spring force in one direction of rotation. To the detecting shaft 23a, a plate 24 is fixed, and the plate 24 has cutouts 24a, 24a at two spots in a region different from the axis of rotation of the detecting shaft 23a. The cutouts 24a, 24a at the two spots are formed with an arrangement equal in distance and angle to the relation between the axis of rotation of the lift arm 7 and the spring pins 25, 25 which the lift arm 7 has at the two points, and the angle sensor 23 is so structured that the cutouts 24a, 24a at the two spots and the spring pins 25, 25 at the two points come in touch with. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sensor mounting structure for mounting a rotation type sensor such as an angle sensor for detecting a rotation angle of a rotating member to a fixed portion.

In general, an angle sensor is well known as a rotary sensor. The angle sensor includes a rotation shaft for coupling with a target member that detects a rotation angle, and the rotation shaft rotates together with the rotation of the target member to detect the rotation angle of the target member. Yes. A signal corresponding to the detected rotation angle is output from the angle sensor, and this signal is used to control the rotation operation of the target member.
Conventionally, for such an angle sensor mounting structure, for example, a technique related to an angle sensor mounting structure for detecting a lift arm angle of an agricultural tractor is disclosed in Patent Document 1 and is publicly known.
In Patent Document 1 in the prior art, an inlay that matches the central axis of a pin (or a frame having a through hole that serves as a bearing for the pin) that is a target member for detecting an angle is formed, and an angle sensor case (or angle sensor) is formed. An angle sensor mounting structure that enables easy positioning of the main body is disclosed.
In addition, an angle sensor mounting structure in which a hole having substantially the same diameter as the detection shaft of the angle sensor is formed in the rotation axis of the lift arm, which is a rotation angle detection target member, and the detection shaft is fitted in the hole, A lever is fixed on both sides of the detection shaft of the angle sensor and the rotation axis of the lift arm, and the lever on the angle sensor side is pressed by the lever on the lift arm side that rotates together with the rotation of the lift arm. A mounting structure for a rotating angle sensor is also widely used and publicly known.
JP-A-9-68420

  However, in the angle sensor mounting structure disclosed in Patent Document 1, the detection axis of the angle sensor and the rotation axis of the detection target (pin) can be accurately aligned, so that the detection accuracy of the rotation angle is good. On the other hand, there is a need for a space for mounting the angle sensor on the detection target member or the like (pin or the bearing frame of the pin). For example, a lift arm that is a detection target member from the case frame like an agricultural tractor. When protruding, the sensor mounting space could not be secured.

  In addition, in the structure in which a hole having substantially the same diameter as the detection shaft of the angle sensor is formed in the rotation axis of the lift arm, which is a rotation angle detection target member, and the detection shaft is fitted in the hole, Adjusting the position makes it easy to adjust the position of the angle sensor and provides good detection accuracy of the rotation angle. However, if the detection shaft of the angle sensor and the hole are eccentrically fitted, extra detection is required. The load on the angle sensor could shorten the life of the angle sensor.

In addition, levers are fixed on both sides of the detection shaft of the angle sensor and the rotation axis of the lift arm, and the lever on the angle sensor side is pressed by the lever on the lift arm side that rotates together with the rotation of the lift arm. In the structure that rotates, there is no risk of applying an extra load to the detection shaft, but the positioning of the angle sensor is difficult, and the accuracy of rotation angle detection and reproducibility when attaching / detaching the angle sensor are ensured. It was difficult to do.
That is, in the conventional angle sensor mounting structure, it has been difficult to achieve both rotation angle detection accuracy, assembling workability, and reliability.

  Therefore, in the present invention, in view of such a current situation, while ensuring the detection accuracy of the sensor, the structure is simplified to facilitate assembly, and the reliability of the sensor is ensured by applying no extra load to the sensor. It is an object of the present invention to provide a rotation sensor mounting structure that can be made.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, according to the first aspect of the present invention, in the rotary sensor mounting structure including a rotary sensor that is connected to the rotary member and detects a rotation angle of the rotary member, and a fixing member that fixes the rotary sensor. The rotating member has two protrusions at a portion different from the rotation axis of the rotating member, and the rotary sensor has a detection shaft biased by a spring force in one rotation direction, and the detection A plate is fixed to the shaft, and the plate has two notches in a portion different from the rotation axis of the detection shaft, and the two notches are provided at two points provided on the rotating member. The protrusion and the rotation axis are arranged so that the distance and the angle are equal, and the rotary sensor is attached so that the two notches and the two protrusions are in contact with each other. Is.

  According to a second aspect of the present invention, the two notches are formed in an arc shape.

  According to a third aspect of the present invention, the two notches are formed in a V shape.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, even when the rotation member that is the detection target of the rotation angle is arranged so as to protrude from the frame, or when there is no space for mounting the rotation type sensor on the detection target itself, the rotation type sensor is accurately Can be attached. Further, the rotary sensor can be attached and detached while maintaining accurate positioning without using a jig or the like.

  According to the second aspect of the present invention, it is possible to accurately adjust the mounting position of the rotary sensor by forming an arc-shaped notch in accordance with the shape of the pin that the plate contacts. This also facilitates assembly and improves the detection accuracy of the sensor.

  According to the third aspect of the present invention, it is possible to reduce the detection error of the sensor when the axial deviation occurs. In addition, the detection accuracy of the sensor can be improved.

Hereinafter, embodiments of the present invention will be described.
In addition, the following embodiment is an example which actualized this invention, Comprising: It is not the thing of the character which limits the technical scope of this invention.
FIG. 1 is a side view showing the overall configuration of an agricultural tractor to which one embodiment of the present invention is applied, FIG. 2 is a side view showing an angle sensor mounting structure according to one embodiment of the present invention, and FIG. 4 is a partially enlarged side view showing the mounting structure of the angle sensor according to the first embodiment of the present invention, FIG. 5 is a partially enlarged side view showing an axial misalignment state in the first embodiment, and FIG. 6 is a second embodiment of the present invention. FIG. 7 is a partially enlarged side view showing a shaft misalignment state in the second embodiment, showing a mounting structure of the angle sensor according to the embodiment.

First, the overall configuration of a tractor that is an example of an agricultural work vehicle to which the present invention is applied will be described with reference to FIG.
The tractor 1 is provided with front wheels 2 and 2 and rear wheels 3 and 3 at the front and rear portions of the airframe, respectively, and a hydraulic cylinder case 21 is fixedly provided on the rear upper part of the transmission case 4. A single-acting hydraulic cylinder is provided in the hydraulic cylinder case 21, and lift arms 7 and 7 that are rotated by expansion and contraction of the hydraulic cylinder are disposed on both the left and right sides of the hydraulic cylinder case 21.
A rotary tiller 14 as an example of a ground working machine is connected to a rear end portion of the three-point link mechanism 12 including the top link 10 and the lower links 11 and 11 by lift arms 7 and 7 so as to freely move up and down. Yes.
Therefore, the rotary tiller 14 connected to the lift arms 7 and 7 is controlled to be lifted or lowered by expanding and contracting the single-acting hydraulic cylinder.
A lift rod 15 and a tilt cylinder 18 are interposed between the lift arms 7 and 7 and the lower links 11 and 11.

Further, the tilting cylinder 18 is expanded and contracted by switching the control valve, so that the rotary tiller 14 can be tilted in the rolling direction (left and right direction), and the horizontal (posture) control of the rotary tiller 14 can be performed. .
Reference numeral 17 denotes a means for detecting the left-right relative between the machine and the work machine, which is composed of a stroke sensor that detects a relative rotation amount between the tractor 1 and the rotary tiller 14, and specifically, It consists of a linear potentiometer.
The stroke sensor 17 is disposed on the lateral side of the tilt cylinder 18 and detects the relative rotation amount by detecting the amount of expansion / contraction of the tilt cylinder 18.
The tilt sensor 16 is an example of a ground detection unit that is attached to an arbitrary position of the machine, for example, a lateral side portion of the hydraulic cylinder case 21 and detects a left and right tilt angle (that is, a ground angle) of the tractor 1.

The hydraulic lift lever 20 is a position control lever, and a pivot base of the hydraulic lift lever 20 is provided with a potentiometer for setting the height of the rotary tiller 14 connected to the rear portion of the tractor 1 to the ground. A ground height setter (not shown) is attached. On the other hand, an angle sensor 23 is provided at the rotation base of the lift arm 7, and the height to the ground is detected by the angle sensor 23, and the lift arms 7 and 7 are placed at positions set by the hydraulic lift lever 20. It is configured to rotate and stop at the set position.
The angle sensor 23 is composed of a rotary potentiometer, a rotary encoder, or the like, and detects the height of the rotary tiller (work machine) 14 by detecting the rotation angle of the lift arm 7.
The above is description about the whole structure of the tractor which is an example of the agricultural work vehicle to which this invention is applied.

Next, an angle sensor mounting structure according to the first embodiment of the present invention will be described with reference to FIGS.
In this embodiment, an angle sensor will be described as an example of a rotary sensor, but the type of sensor to which the present invention is applied is not limited to this.
As shown in FIG. 2 or 3, the angle sensor 23 has a detection shaft 23 a serving as a rotation detection shaft, and a fixed plate 23 b for fixing the angle sensor 23. And it is set as the structure fastened with the screw | screw and nut with respect to the bracket 26 using the hole provided in the fixed plate 23b.
A female thread for attaching the plate 24 is provided on the end axis of the detection shaft 23a, and the plate 24 is fixed by fastening a bolt using the female thread.
Further, the detection shaft 23a is constantly urged in one rotation direction by a spring (not shown) built in the angle sensor 23, and is constant in a state where the detection shaft 23a does not receive a binding force in the rotation direction from the outside. It is a structure that returns to the position. That is, a spring force is always urged in the counterclockwise direction in FIG. 2 on the detection shaft 23a, and when the lift arm 7 is rotated (raised) counterclockwise, it is in contact with the spring pin 25. It is configured to rotate counterclockwise.

As described above, the angle sensor 23 is fixed with the plate 24 that contacts the detection target. The plate 24 is a lever-like member extending in two directions with the detection shaft 23a as a central axis, and a notch 24a is formed in each direction. That is, the plate 24 is formed in a long plate shape, and a bolt hole for inserting a fixing bolt is opened at the center in the longitudinal direction, and a spring is formed on the front surface (front side) in a direction rotated by being biased by springs on both sides thereof. Arc-shaped notches 24a and 24a are formed to match the outer diameter of the pin 25.
On the other hand, two spring pins 25 serving as protrusions are provided on the lift arm 7 serving as a rotating member to be detected. In other words, the spring pins 25 and 25 are protruded laterally on the side surface of the rotation base (lift arm shaft 7a) of the lift arm 7 as columnar protrusions at diametrical positions away from the rotation center by a predetermined distance. The plate 24 is disposed so as to be able to contact the tip of the spring pins 25.

  As shown in FIG. 4, when the notches 24a and 24a and the spring pins 25 and 25 formed in the plate 24 are in contact with each other at two locations, the lift arm shaft 7a for fixing the lift arm 7 and the detection shaft 23a are fixed. The dimensions are set so that the axes coincide. As a result, positioning is performed so that the notches 24a and 24a are in contact with the spring pins 25 and 25, and the bracket 26 is fixed to the cylinder case 21 with the bolts 27, so that the angle can be easily adjusted without using a mounting jig or the like. The sensor 23 can be positioned and adjusted. The bracket 26 has a plate bent in a crank shape in a rear view, one end fixed to the cylinder case 21, an angle sensor 23 attached to the other end, and a detection shaft 23a protruding toward the lift arm shaft 7a. However, the plate may be attached to the lift arm shaft side and the pin may be attached to the angle sensor 23 side.

  Further, since the lift arm shaft 7a and the detection shaft 23a are in contact with each other via the spring pins 25 and 25 and the plate 24, the detection shaft 23a is in contact with the lift shaft 7a even if a shaft misalignment occurs between the both 7a and 23a. There is no extra load.

That is, the mounting of the angle sensor 23 provided with the lift arm 7 fixed on both sides of the lift arm shaft 7a and the angle sensor 23 that is fixed to the cylinder case 21 on the machine side and detects the rotation angle of the lift arm 7. In the structure, the lift arm 7 has two spring pins 25 and 25 at portions different from the rotational axis of the lift arm 7, and the angle sensor 23 is a detection shaft that is biased by a spring force in one rotation direction. 23a, and a plate 24 is fixed to the detection shaft 23a. The plate 24 has two cutout portions 24a and 24a at portions different from the rotational axis of the detection shaft 23a. The notches 24a and 24a have the same distance and angle in the relationship between the rotational axis of the lift arm 7 and the two spring pins 25 and 25 provided on the lift arm 7 and the rotational axis. Placed in the angle sensor 23, the spring pin 25, 25 of the notch portion 24a-24a and the two points at two positions are the so mounted structure in contact.
As a result, the angle sensor can be accurately attached even when the rotation member that is the detection target of the rotation angle is arranged so as to protrude from the frame, or even when there is no space to attach the angle sensor to the detection object itself. is there. Further, the angle sensor can be attached and detached while maintaining accurate positioning without using a jig or the like.

As shown in FIG. 5, when the lift arm shaft 7a and the detection shaft 23a are misaligned, one spring pin 25 is not in contact with the plate 24, so that no extra load is applied to the detection shaft 23a. Yes.
For convenience of explanation, FIG. 5 shows a state where the shaft misalignment is large, but as described above, the shaft misalignment can be generated by attaching the notches 24a and 24a and the spring pins 25 and 25 so as to be in proper contact. Since it can be minimized, a situation in which the detection accuracy is significantly reduced can be easily avoided by carrying out daily inspection work such as visual confirmation.

In the first embodiment, the shape of the notch 24a is formed in an arc shape in accordance with the outer shape of the spring pin 25, so that the notch 24a and the spring pin 25 are in contact with each other accurately. It is easy to adjust.
As a result, the angle sensor 23 and the lift arm shaft 7a can easily fix the sensor at substantially the same position so as to obtain the necessary detection accuracy, and the result of repeated rotational movement due to the axial displacement of the minute detection shaft 23a. An extra load is not applied to the sensor and the life of the sensor is not impaired.

That is, the two notches 24a and 24a are formed in an arc shape, and thus the notch portion 24a is an arc-shaped notch that matches the shape of the pin with which the plate contacts, It is possible to accurately adjust the mounting position of the angle sensor.
This also facilitates assembly and improves the detection accuracy of the angle sensor.
The above is the description of the angle sensor mounting structure according to the first embodiment of the present invention.

Next, an angle sensor mounting structure according to a second embodiment of the present invention will be described with reference to FIG. 6 or FIG.
As shown in FIG. 6, the basic structure of the second embodiment is the same as that of the first embodiment, but differs from the first embodiment in that the shape of the notch 24b is V-shaped. . Moreover, the notch 24b is formed so that the angle between the valleys formed by the V-shape is an obtuse angle.

  As shown in FIG. 7, by making the angle between the valleys formed by the V-shaped obtuse, the error between the position where the spring pin 25 is in contact with the notch 24b at the time of axial misalignment and the position where there is no axial misalignment is the first. Since the detection angle error can be reduced as compared with the first embodiment, the detection angle error can be further reduced as compared with the first embodiment.

That is, the two notches 24b and 24b are formed in a V-shape, which makes it possible to reduce the error in the sensor detection angle when an axial shift occurs compared to the first embodiment. It is. In addition, the detection accuracy of the angle sensor can be further improved compared to the first embodiment.
The above is the description of the angle sensor mounting structure according to the second embodiment of the present invention.

The side view which shows the whole structure of the agricultural tractor to which one Example of this invention is applied. The side view which shows the attachment structure of the angle sensor which concerns on one Example of this invention. Similarly rear view. The partial expanded side view which shows the attachment structure of the angle sensor which concerns on the 1st Example of this invention. The partial expanded side view which shows the axial shift | offset | difference state in a 1st Example. The partial expanded side view which shows the attachment structure of the angle sensor which concerns on the 2nd Example of this invention. The partial expanded side view which shows the axial shift | offset | difference state in 2nd Example.

Explanation of symbols

7 Lift arm 23 Angle sensor 23a Detection shaft 24 Plate 24a Notch 25 Spring pin

Claims (3)

A rotary sensor connected to the rotary member for detecting the rotation angle of the rotary member;
A fixing member for fixing the rotary sensor;
In the mounting structure of the rotary sensor with
The rotating member is
Having two protrusions at a portion different from the rotational axis of the rotating member;
The rotational sensor is
Having a detection shaft biased by a spring force in one rotation direction,
A plate is fixed to the detection shaft,
The plate
Having two notches in a portion different from the rotational axis of the detection shaft,
The two notches are
The distance and the angle are equal in the relationship between the two projections provided on the rotating member and the rotation axis,
The rotational sensor is
The two notches and the two protrusions are attached so as to contact each other;
The mounting structure of the rotary sensor characterized by the above. The two notches are
Formed in an arc shape,
The rotation type sensor mounting structure according to claim 1. The two notches are
Formed into a V-shape,
The rotation type sensor mounting structure according to claim 1.

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