JPH0633799Y2 - Operating angle detection sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an operation angle for detecting an angle at which a rotating shaft rotatably supported is rotated with respect to a bearing body of the rotating shaft. Regarding improvement of a detection sensor.

[Conventional technology]

A conventional operating angle detection sensor of this type is shown in FIGS. 3 and 4, which will be described below.

In the figure, reference numeral 1 is a rotating shaft, and 2 is a case supporting the rotating shaft. A contact holder 3 having a movable contact 4 is fixed to the upper end of the rotating shaft 1, and the movable contact 4 is attached to the upper surface of the case 2. The cover 9 is in contact with the fixed contact plate 8, and the movable contact 4 and the fixed contact plate 8 are turned off depending on the rotation angle of the rotating shaft 1.

A part of the rotating shaft 1 is cut to have a D-shaped cross section, and the spring 6 is provided between the case 2 and the spring retainer 7.
The cylinder 5 mounted with is attached to the D-shaped flat portion by pressure.

Therefore, when the rotating shaft 1 is rotated, the D-shaped flat portion compresses the spring 6 via the cylinder 5, and when the rotating angle becomes a certain value or more, the gap between the movable contact 4 and the fixed contact plate 8 is increased. Is turned off, and it is detected that the rotation of the rotation shaft 1 has reached a predetermined angle or more.

When the force that rotates the rotating shaft 1 is released, the D-shaped flat surface portion is pressed by the pressing force of the spring 6 against the cylinder 5, and the whole end surface of the cylinder 5 is rotated until the entire D-shaped flat surface contacts. The moving shaft 1 rotates and returns to the initial position.

[Problems to be solved by the invention]

In the conventional operating angle detection sensor, the cylinder 5 is required, so that the whole size becomes large.

The allowable rotation angle of the rotary shaft 1 varies depending on the D-shaped cutting depth, and is 90 degrees or less and half or less when the cutting residue of the rotary shaft 1 up to the D-shaped plane is more than half. As a result, the allowable angle becomes larger, but the rotating shaft 1 becomes weaker and the risk of breakage increases.

Also, the moment l of the returning force by the cylinder 5 is
Is less than or equal to the radius of, and since this l is small, the force of the spring 6 must be increased in order to obtain a reliable restoring force, and as a result, the operating torque for rotating the rotating shaft 1 becomes heavy. There is.

The present invention solves the above-mentioned drawbacks of the conventional motion angle detection sensor and enables not only detection of a large rotation angle, but also
Provided is an operation angle detection sensor having a large rotation angle and a low operation torque, such as a detection sensor having a large rotation angle until the completion of passage of rice, such as a rice detection sensor of a rice harvester. Is intended.

[Means for solving problems]

In order to achieve the above object, the motion angle detection sensor according to the present invention is fixed to a case having a rotary shaft, a bearing for supporting the rotary shaft, and a rotary shaft end protruding outside the case. A detection arm, a contact holder having a movable contact fixed to the end of the rotating shaft protruding into the case, and wound around the bearing portion in the case, and between the contact holder and the case. A first spring mounted so as not to apply an urging force to the rotating shaft at a neutral position of the rotating shaft, and a hole formed in a side surface of the contact holder facing the inner surface of the case. And a second spring that is housed in the hole and is biased by the second spring so that the inner surface of the case is brought into sliding contact with the inner surface of the case by the rotation of the rotation shaft. Thrust And a recess having a predetermined inclination angle formed on the inner surface of the case so that the ball falls at a neutral position of the rotating shaft. The first spring is wound or unwound by the rotation of the rotation shaft by the detection arm, and the rotation of the rotation shaft, which constitutes detection means such as a switch and a variable resistor operated by rotation. An urging force that returns the rotating shaft to the neutral position is generated by an urging force of the second spring, which is compressed to move the ball up the recessed portion by movement.

[Action]

In the above structure, when the rotation shaft is rotated from the neutral position by the detection arm, the first spring is wound or unwound in the rotation direction, so that the first spring neutralizes the rotation shaft. The restoring force that tries to return to the position is generated. Further, when the rotation shaft rotates and the ball accommodated in the hole of the rotation shaft moves together with the rotation shaft, the ball rides up the recess and the second spring is compressed, Second when the ball is in the inclined part of the recess
The spring generates a restoring force that tends to return the rotary shaft to the neutral position, so that by selecting the strengths of the first and second springs, it is possible to easily obtain a small operating torque.

Further, the restoring force of the first spring is extremely small when the turning angle of the turning shaft is small, and increases as the turning angle increases, whereas the restoring force of the second spring completely rides on the recess. It is the largest at a small rotation angle until it rises, and the restoring force becomes 0 when the rotation angle becomes large.

Moreover, since the first spring is wound around the bearing portion of the rotary shaft and the second spring is housed in the hole of the contact holder, the space can be effectively used.

[Example of device]

An example of the implementation of the present invention will be described below with reference to FIGS.

This operation angle detection sensor is used as a sensor that operates the rice harvesting mechanism and stops the rice harvesting mechanism when it runs out.

In the figure, 10 is a rotating shaft, and a detection arm is provided at the lower end thereof.
A rotary shaft 10 is rotatably supported by a case 12, and a contact holder 13 having a movable contact 16 is fixed to the upper end of the rotary shaft 10.

The movable contact 16 contacts the fixed contact plate 17 of the cover 18 attached to the upper surface of the case 12, and when the rotation angle of the rotation shaft 10 becomes a predetermined angle or more, the movable contact 16 and the fixed contact plate.
It is turned off during 17 and it is detected that the rotation angle of the rotation shaft 10 is equal to or larger than a predetermined angle.

That is, in the rice reaper, it is detected that the detection arm 19 is pushed by the rice and the rotary shaft 10 is rotated, and the rice reaper mechanism is activated.

A spring 11 as a first spring is wound around a bearing portion of a case 12 that supports the rotating shaft 10, one end of which is a hole of the contact holder 13 and the other end of which is a case.
Fastened to 12.

Therefore, when the detection arm 19 is rotated, the spring 11 is wound or unwound, and an urging force for returning to the initial state is generated.

Then, a hole is formed in one side surface of the contact holder 13, a spring 15 as a second spring and a ball 14 are accommodated in the hole, and when the rotation shaft 10 rotates, the ball 14 is urged by the spring 15. The inner surface of the case 12 is rubbed by.

A recess 12a having an angle θ is formed on the inner surface of the case 12 that contacts the ball 14 when the rotating shaft 10 is in a neutral state where no force is generated in the spring 11.

Therefore, when the rotation shaft 10 is rotated by the angle α by the detection arm 19, the spring 11 is also wound or unwound by the angle α.
The moment M generated at 11 is However, E: longitudinal elastic modulus d: wire diameter of spring 11 N: number of turns.

In this way, the rotation moment M with respect to the rotation shaft 10 increases in proportion to the rotation angle, and this acts as a restoring force of the rotation shaft 10.

Thus, when the rotation angle of the rotation shaft 10 is small, the restoring force is also small, and the rotation shaft 10 becomes unstable.

The moment M ′ for the ball 14 to ride up the recess 12a is M ′ = PLtan θ where P is the mounting load of the spring 15 L is the distance from the center of the rotating shaft 10 to the center of the ball 14.

With this moment M ', the neutral position of the rotary shaft 10 becomes clear, and in combination with the above-mentioned rotational moment M, a stable restoring mechanism can be obtained.

[Effect of device]

As described above, according to the present invention, when the rotation shaft is rotated from its neutral position by the detection arm, the first spring is wound or unwound in the rotation direction, so that the first spring is rotated. The spring generates a restoring force that tries to return the rotating shaft to the neutral position. In addition, when the rotation shaft rotates and the ball housed in the hole of the rotation shaft moves together with the rotation shaft, the ball rides up the recess and the second spring is compressed, When the ball is in the inclined part of the recess, the second spring generates a restoring force that tries to return the rotation shaft to the neutral position. Therefore, it is easy to select the strength of the first and second springs. It is possible to obtain a small operating torque.

Further, the restoring force of the first spring is extremely small when the turning angle of the turning shaft is small, and increases as the turning angle increases, whereas the restoring force of the second spring completely rides on the recess. It is the largest at a small turning angle until it goes up, and the restoring force becomes 0 when the turning angle becomes large, so both springs can cooperate to surely return the turning shaft to the neutral position. The spring is wound around the bearing portion of the rotating shaft, and the second spring is accommodated in the hole of the contact holder. Therefore, the space can be effectively used and the size and weight can be reduced as compared with the conventional product. Can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line BB of the same as above, FIG. 3 is a vertical sectional view of a conventional operating angle detecting sensor, and FIG. FIG. 10 ... Rotating shaft, 11 ... Spring, 12 ... Case, 12a ... Recess, 13 ... Contact holder, 14 ... Ball, 15 ... Spring, 16 ... Movable contact, 17 ... Fixed contact plate.

Claims (1)

[Scope of utility model registration request] 1. A rotating shaft, a case having a bearing for supporting the rotating shaft, a detection arm fixed to an end of the rotating shaft protruding outside the case, and a rotating protruding inside the case. A contact holder fixed to the shaft end and having a movable contact, and wound around the bearing portion in the case, and between the contact holder and the case, at the neutral position of the rotary shaft, at the rotary shaft. A first spring mounted so as not to apply an urging force; a second spring housed in a hole formed in a side surface of the contact holder facing the inner surface of the case; and a second spring housed in the hole. A ball that is housed and biased by the second spring, and is abutted against the inner surface of the case so that the inner surface of the case is brought into sliding contact with the inner surface of the rotating shaft; In the neutral position A detecting part such as a switch, a variable resistor or the like, which is provided with a recess formed on the inner surface of the case so as to allow the ball to fall and having a predetermined inclination angle, and which is operated by the rotation of the rotation shaft by the movable contact. And is wound by the rotation of the rotation shaft by the detection arm,
Alternatively, the turning shaft is moved to the neutral position by the urging force of the first spring that is released and the second spring that the ball rides up on the recess and is compressed by the turning of the turning shaft. An operation angle detection sensor characterized in that it generates a biasing force to return to.