JP7205319B2 - Rotation angle detector - Google Patents

Description

The present invention relates to a rotation angle detection device having a sensor that detects the rotation angle of a rotating member and a coil spring that exerts a biasing force to return the rotating member to a predetermined rotation angle.

As a rotation angle detection device having the above configuration, Patent Document 1 discloses that a rotating member that rotates together with a shaft member supports a magnet, is equipped with a magnetic sensor that detects the magnetic flux of the magnet, and returns the rotated rotating member to a predetermined rotational posture. A configuration in which a coil spring (coil spring in the literature) is provided and a rotating member is accommodated in a housing (housing in the literature) is described.

In Patent Document 1, when a rotating member rotates in conjunction with the operation of an operation pedal or the like of a vehicle, a change in magnetic flux accompanying this rotation is detected by a magnetic sensor, and the rotation angle of the operation pedal, etc. dynamic angle) can be detected. Further, when the operating pedal or the like is not operated, the rotating member is held in the initial posture by the urging force of the coil spring. The torsion spring described in Patent Document 1 also functions as an alignment mechanism for aligning a rotating member.

In Patent Document 2, as a rotation angle detection device (rotation angle detection device in the document), a rotating member is housed in a case, a magnet is provided in the rotating member (rotating body in the document), and a magnetic detecting element that detects the magnetic flux of the magnet. and a coil spring (a spring in the literature) that exerts a biasing force on the rotating member in the rotational direction.

This patent document 2 describes that the rotation angle detection device is used to detect the rotation angle of the brake pedal of an automobile.

JP 2007-139458 A JP 2012-73231 A

When the vehicle is equipped with the rotation angle detection devices described in Patent Documents 1 and 2, the coil spring may vibrate due to vibration during running, and the wire rods of the coil spring may come into contact with each other, causing abnormal noise. there were. In particular, in vehicles such as hybrid and EV vehicles, which are very quiet, the noise generated by the coil springs can be annoying to the driver or even make the driver feel uncomfortable. it was thought.

In the rotation angle detection devices described in Patent Documents 1 and 2, one end of the wire of the coil spring is locked to the housing (the case in Patent Document 2), and the other end of the wire is locked to the rotating member. configured. Therefore, when an external vibration force acts on the wire, the wire at the position farthest from the locking position in the radial direction of the coil spring is displaced the most, causing the wires to come into contact with each other and generate abnormal noise. was also considered.

In other words, when the wires of the coil spring are displaced due to vibration, the gap between the wires at positions facing each other across the coil axis of the coil spring (at 180° in the circumferential direction) changes greatly with respect to the locking position. As a result of this change, it was thought that abnormal noise was generated.

In particular, in a coil spring having end turns formed at both ends of an effective winding portion, the distance between the wire rods of the end turn portion and the effective winding portion is shorter than the distance between the wire rods of the effective winding portions. Therefore, it was thought that the wires would come into contact with each other and generate abnormal noise.

For these reasons, there is a need for a rotation angle detection device capable of suppressing the occurrence of abnormal noise even with a configuration using a coil spring that exerts an urging force on the rotating member in the rotational direction.

A rotation angle detection device according to the present invention is characterized by a rotating member supported rotatably around a rotation axis with respect to a housing, and rotating the rotating member from a reference posture to a rotating posture with respect to the housing. a rotation angle sensor for detecting a rotation angle when the rotating member is rotated; an engaging portion at one end engages the rotating member to return the rotating posture of the rotating member to the reference posture; The engaging portion includes a coil spring that engages with the housing, and the coil spring is formed at least one end of an effective winding portion formed by spirally forming a wire rod at a predetermined pitch and at least one end of the effective winding portion. The coil spring is twisted by a predetermined angle in a tension direction and compressed by a predetermined ratio with reference to a free state in which no load is applied, and the effective winding portion and the seat are in a state of compression. Using the boundary with the winding portion as a boundary position, a position separated by 180° from this boundary position in the winding direction to the effective winding portion, and a position separated by 180° from the boundary position in the winding direction to the end turn portion. is set to 0.42 times or more of the inner width of the wire rods in the effective winding portion, and the coil spring is accommodated in the case in the above state.

In the coil spring, the wire at a position separated by 180° in the winding direction of the wire relative to the boundary between the effective winding portion and the end turn portion can be relatively freely displaced. Further, in the conventional coil spring, the inner width between the wire rods at positions separated from each other by 180° in the winding direction of the wire rod with respect to the boundary between the effective winding portion and the end turn portion is the inner width between the wire rods of the effective winding portion. Because it is an extremely small value (less than 1%) compared to the .

On the other hand, according to the above-described characteristic configuration, with the boundary between the effective winding portion and the end winding portion as the boundary position, a position separated by 180° in the winding direction from the boundary position to the effective winding portion and the end winding portion from the boundary position By setting the inner width between the wire rods at positions separated by 180 ° in the winding direction to 0.42 (42%) times or more of the inner width between the wire rods in the effective winding part, the inner width between the wire rods It is made sufficiently large to enable suppression of contact between wires. In particular, FIG. 7 shows a graph of the noise level of abnormal noise generated when the same vibration is applied to the conventional coil spring and the coil spring of this characteristic configuration. As shown in the figure, with the noise characteristics of the conventional coil spring (conventional product), the noise level is high even at low vibration acceleration, but with the coil spring having this characteristic configuration (product of the present embodiment), it can withstand high vibration acceleration. The noise level does not increase greatly even when the temperature reaches the maximum, and the effect of suppressing the generation of abnormal noise can be confirmed.
As a result, a rotation angle detection device capable of suppressing the generation of abnormal noise even with a configuration using a coil spring that exerts an urging force on the rotating member in the rotation direction has been constructed.

As another configuration, the end turn portion may be formed at both end positions of the effective turn portion.

According to this, although the end turn portion is formed at both ends of the effective turn portion, it is possible to prevent the wire rods from contacting each other between the end turn portion and the effective turn portion at both end portions.

As another configuration, the predetermined angle may be 100° and the predetermined ratio may be 73-77%.

Normally, in the rotation angle detection device, the coil spring is accommodated in the housing in a compressed state. Therefore, according to this configuration, the biasing force of the coil spring extending in the direction of the spring axis rotates the rotating member, for example. It is also possible to maintain high detection sensitivity and detection accuracy by holding at a position close to the angle sensor.

1 is a cross-sectional view of a rotation angle detection device; FIG. FIG. 3 is a cross-sectional view of the rotation angle detection device in an exploded state; 1 is an exploded perspective view of a rotation angle detection device; FIG. 4 is a perspective view of a torsion spring in a state of being twisted by a predetermined angle from a free state and compressed by a predetermined ratio; FIG. FIG. 4 is a cross-sectional view of a torsion spring in a state of being twisted by a predetermined angle from a free state and compressed by a predetermined ratio; 5 is a graph showing the distance between wire rods in the free length and the distance between wire rods in the tension state of the conventional torsion spring and the torsion spring of the present embodiment. 5 is a graph showing noise levels of a conventional torsion spring and a torsion spring of the present embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
[Basic configuration]
As shown in FIGS. 1 to 3, the housing A includes a housing 10, a housing cover 20, a rotating member 30, a rotation angle sensor 2, and a torsion spring 40 (an example of a coil spring). A rotation angle detection device S is constructed by

As shown in FIGS. 1 and 2, the rotary member 30 is housed inside the housing 10 so as to be rotatable around the rotation axis X with respect to the housing A. As shown in FIG. The rotating member 30 includes a shaft 32 assembled coaxially with the rotation axis X, and an operating arm 1 connected to the outer end of the shaft 32. When the operating arm 1 is operated, the rotating member 30 rotates. A rotation angle sensor 2 for detecting an angle is provided in the housing 10 . A torsion spring 40 is accommodated in the housing cover 20 to exert a biasing force to return the rotating member 30 to the reference posture when the operating arm 1 is not operated.

This rotation angle detection device S is used for detecting the operation angle of an accelerator pedal, a brake pedal, or the like in a vehicle such as an automobile. That is, the rotating member 30 is provided with a permanent magnet M, and the rotation angle sensor 2 is provided with a magnetic detection element such as a Hall element for detecting the density and direction of the magnetic flux acting from the permanent magnet. 2 is supported on the substrate 3 .

With this configuration, the operation amount of the accelerator pedal or the like can be detected by the rotation angle detection device S by supporting the housing A on the vehicle body frame or the like and linking the accelerator pedal or the like with the operating arm 1 . Specifically, when the operation arm 1 rotates about the rotation axis X, the magnetic flux density and magnetic flux direction acting on the rotation angle sensor 2 from the permanent magnet M change along with this rotation. A rotation angle of the rotating member 30 is detected. The permanent magnet M may be a samarium-cobalt magnet, a rare earth magnet such as a neodymium magnet, an alnico magnet, a ferrite magnet, or the like.

In the rotation angle detection device S, the housing 10 and the housing cover 20 are made of insulating resin. The rotation axis X is the center of rotation of the rotating member 30 and does not indicate a specific position of the housing 10 or the like. In the specification, the positional relationship of each member constituting the rotation angle detection device S and the posture of each member are described with reference to the rotation axis X. FIG.

[Chassis]
As shown in FIGS. 1 and 2, the housing 10 is internally formed with a partition 11 having a posture orthogonal to the rotation axis X, and a portion adjacent to the housing cover 20 from the partition 11 is centered on the rotation axis X. A concave accommodation space 10R is formed in which the rotary member 30 is accommodated. A sensor space 10S is formed in a portion adjacent to the outside of the partition wall 11 (on the side opposite to the housing cover 20).

The housing 10 is integrally formed with a connector portion 12 protruding outward perpendicular to the rotation axis X. As shown in FIG. Further, the housing 10 is detachably provided with a cover plate 13 that covers the opening outside the sensor space 10S. Further, the housing 10 accommodates the rotation angle sensor 2 supported by the substrate 3 in the sensor space 10S, and exposes the lead wire (not shown) conducting to the rotation angle sensor 2 to the inner space of the connector portion 12. ing.

As shown in FIGS. 1 to 3, the housing 10 has a connecting wall 14 formed at a position surrounding the edge of the opening of the accommodation space 10R, and a plurality of position fixing members protruding outward from a part of the outer surface of the connecting wall 14. A piece 15 is formed.

A fitting wall 21 projecting toward the housing 10 is formed in a region of the housing cover 20 facing the housing 10 along the outer peripheral edge. The fitting wall 21 is formed at a position surrounding the outer surface of the protruding end of the connecting wall 14 of the housing 10. At a plurality of locations of the fitting wall 21, there are fitting recesses 21a into which the position fixing pieces 15 can be fitted. is formed.

Further, the housing cover 20 has a bulging wall 22 that protrudes outward (the side opposite to the housing 10). A space 20S is formed. A through hole 22b is formed coaxially with the rotation axis X in a flat bulge inner wall surface 22a perpendicular to the rotation axis X at the protruding end portion of the inner surface of the bulge wall 22 . Further, a fixed-side protrusion 23 having a posture along the rotation axis X is formed on the bulging inner wall surface 22a.

A guard wall 24 is formed on the outer peripheral portion of the housing cover 20 on the opposite side of the housing 10 so that a portion of the guard wall 24 opens sideways (in a direction perpendicular to the rotation axis X). As shown in FIG. 3, the housing cover 20 is formed with a pair of flanges 25 protruding outward from positions outside the guard wall 24 . In particular, as shown in FIG. 1, the operation arm 1 is arranged in a posture in which the proximal end portion is connected to the shaft 32 and extends outward from the open portion of the guard wall 24 . As a result, one opening edge of the open portion of the guard wall 24 is used as a stopper 24a, and the posture of the operating arm 1 in contact with this stopper 24a is the reference of the operating arm 1 (rotating member 30). Posture.

[Rotating member]
As shown in FIGS. 1 to 3, the rotating member 30 includes a rotating body 31 having a cylindrical shape centered on a rotating shaft center X, and a shaft connected to the rotating body 31 and arranged coaxially with the rotating shaft center X. 32 and a permanent magnet M embedded in the rotating body 31 .

The base end of the shaft 32 is inserted into the rotating body 31 so as to rotate together with the rotating body 31 . The shaft 32 protrudes from the rotating body 31 toward the housing cover 20, and a bushing 33 is rotatably fitted onto the shaft 32. As shown in FIG. The bush 33 may be made of either a resin material or a metal material.

A rotation-side protrusion 34 that protrudes in a posture parallel to the rotation axis X is formed on the facing surface 31 a of the rotation body 31 that faces the housing cover 20 . When the rotating member 30 is installed in the rotation angle detecting device S, the facing surface 31a of the rotating member 30 is positioned perpendicular to the rotation axis X and parallel to the bulging inner wall surface 22a of the housing cover 20. Posture.

[Torsion spring]
As shown in FIGS. 1 to 5, the torsion spring 40 (an example of a coil spring) has an effective winding portion 41 formed by spirally forming a wire made of spring steel at a predetermined pitch, and formed at both ends of the effective winding portion 41. and an end turn portion 42 . Further, the torsion spring 40 has an engaging portion 43 formed by bending the end of each end turn portion 42 into a hook shape.

Assuming a spring axis C as shown in FIGS. 4 and 5, the effective winding portion 41 is formed by spirally winding a wire around the spring axis C at a predetermined pitch. On the other hand, the pair of end turn portions 42 are formed by winding a wire in such a manner that the outer ends thereof are orthogonal to the spring axis C. As shown in FIG.

The torsion spring 40 is twisted by a predetermined angle in the tension direction from a free state where no load is applied, and is compressed by a predetermined ratio in the compression direction from the free state. 31a and the bulging inner wall surface 22a of the housing cover 20 (see FIG. 1).

During this accommodation, one end turn portion 42 abuts against the bulging inner wall surface 22 a , and the engaging portion 43 of this end turn portion 42 engages with the fixed-side projecting portion 23 . The other end turn portion 42 abuts against the facing surface 31 a of the rotating member 30 , and the engaging portion 43 of this end turn portion 42 engages with the rotation-side projection 34 .

As a specific value of the predetermined angle, in this embodiment, the torsion spring 40 is twisted by 100° in the tension direction based on the free state where no load acts. As a specific value of the predetermined ratio, the torsion spring 40 is compressed to 73% in the compression direction based on the free state where no load acts.

As shown in FIG. 5, the torsion spring 40 has a wire diameter d of 0.9 mm, and is twisted at a predetermined angle (100° in this embodiment) in the direction of tension from a state where no load is applied. The average diameter D (the diameter of the circle drawn by the center of the wire) is 18 mm, the number of turns of the effective winding portion 41 is 2.5, and the number of turns of the end winding portion 42 is 1.

In this rotation angle detection device S, since the torsion spring 40 is twisted in the direction of tension, the operation arm 1 reliably abuts against the stopper 24a when no operation force acts on the operation arm 1, and the rotation member is rotated. 30 is maintained in the reference posture. At this time, the torsion spring 40 is in a state of being twisted by 70° in the tension direction from the free state and in a state of being compressed by 73% in the compression direction from the free state.

In this rotation angle detection device S, as described above, the torsion spring 40 is compressed so that the outer surface of the rotating member 30 (opposite side of the facing surface 31a in the direction along the rotation axis X) is aligned with the partition wall 11 of the housing 10. is maintained in close proximity to As a result, fluctuations in the magnetic flux density acting on the rotation angle sensor 2 from the rotating member 30 can be suppressed to achieve highly accurate detection, and the detection angle of the rotation angle sensor 2 can be increased.

In addition, in the torsion spring 40, the spacing (inner width) between the wires is set so as to suppress the generation of abnormal noise due to contact between the wires when vibrations act from the outside.

As shown in FIGS. 4 and 5, when the torsion spring 40 is twisted by 100° in the tension direction and compressed by 73% in the compression direction, the boundary between the effective winding portion 41 and the end winding portion 42 is positioned at the boundary position. Let P. A position separated by 180° in the winding direction from the boundary position P to the effective winding portion 41 is defined as a first intermediate position Q1, and a position separated by 180° in the winding direction from the boundary position P to the end turn portion is defined as a first intermediate position Q1. 2 to the middle position Q2.

In this state, the inter-wire distance Gm (inner width between the two intermediate positions) between the first intermediate position Q1 and the second intermediate position Q2 is the inter-wire distance of the effective winding portion 41. It is set to be 0.42 times or more of the effective portion interval Ga (the inner width between the wire rods of the adjacent effective winding portions 41).

The angle that can be detected by the rotation angle detection device S is set to about 110° from the reference posture in which the operating arm 1 contacts the stopper 24a. In other words, the torsion spring 40 is configured to be twistable by a maximum of 180 degrees in the tension direction from the natural state.

As described above, each end turn portion 42 is formed by one turn of wire in a state of being twisted by 100° in the tension direction from the free state and compressed by 73% in the compression direction. A wire rod 41 is formed so as to have 2.5 turns.

Due to the structure of the torsion spring 40 as described above, the end turn portion 42 is a region of the wire from the tip position of the end turn portion 42 where the engaging portion 43 is formed to the position reaching 360° along the wire. In addition, the effective winding portion 41 includes a region exceeding 360° along the wire from the tip of the wire, and the position of this 360° is the boundary position P between the effective winding portion 41 and the end turn portion 42. Become.

As shown in FIGS. 1 and 2, the torsion spring 40 is housed in the spring space 20S of the housing cover 20 at a position surrounding the bush 33. As shown in FIG.

[Assembly of rotation angle detector]
When assembling the rotation angle detection device S, the shaft 32 of the rotating member 30 is fitted in the bush 33, the torsion spring 40 is arranged in a position surrounding the bush 33, and one engaging portion 43 of the torsion spring 40 is engaged. Work is performed to pre-engage the rotation-side protrusion 34 and to pre-engage the other engaging portion 43 with the fixed-side protrusion 23 .

After that, the rotary member 30 is accommodated in the accommodation space 10R of the housing 10, and the torsion spring 40 is accommodated in the spring space 20S of the housing cover 20. As shown in FIG. In this accommodated state, the plurality of position fixing pieces 15 formed on the outer surface of the connecting wall 14 of the housing 10 are fitted into the corresponding ones of the plurality of fitting recesses 21a of the fitting wall 21 of the housing cover 20, The housing 10 and the housing cover 20 are superimposed on each other in the direction along the rotation axis X, and the housing 10 and the housing cover 20 are connected and fixed by a welding technique or an adhesive. In this state, the torsion spring 40 is twisted from the free state by 70° in the tension direction and compressed to 73% in the compression direction.

When the housing 10 and the housing cover 20 are overlapped, the protruding end of the shaft 32 is inserted into the through hole 22b of the housing cover 20, and after the housing 10 and the housing cover 20 are connected and fixed, the bulging wall 22 is formed. The operation arm 1 is connected and fixed to the tip position of the shaft 32 inserted through the through hole 22b.

Further, the step of mounting the rotation angle sensor 2 supported by the substrate 3 in the sensor space 10S of the housing 10 may be performed before or after the housing 10 and the housing cover 20 are connected and fixed. good.

In the assembled rotation angle detection device S, the biasing force of the torsion spring 40 keeps the operating arm 1 in contact with the stopper 24 a of the guard wall 24 . As a result, the operation arm 1 moves away from the stopper 24a when detecting the operation amount of the accelerator pedal or the like.

[Quietness of torsion spring]
In order to compare the torsion spring 40 configured as in this embodiment (this embodiment product) with a conventional torsion spring (conventional product), FIG. A graph is shown in which the angle is plotted on the horizontal axis, the value of the interval (inner width) between adjacent wire rods is measured at each measurement point, and the measurement results are plotted on the vertical axis.

In the graph shown in FIG. 6, the measurement points are displaced at intervals of 30° in the circumferential direction from the tip position of the end turn portion 42 around the spring axis C (see FIGS. 4 and 5). It shows the spacing (inner width) of the wires. In the graph of FIG. 1, two types of graphs, "this embodiment product" indicated by ◯ (white circle) and "conventional product" indicated by Δ (white triangle), show the characteristics in the free state. In addition, two types of graphs, “this embodiment product” indicated by “black circles” and “conventional product” indicated by “black triangles”, are compressed to 73% and twisted by 100° (compressed in the graph). + torsion).

As described above with reference to FIG. 5, the graph shown in FIG. 6 shows that when the torsion spring 40 of the present embodiment and the conventional torsion spring measure the distance between the wires, The wire diameter d is 0.9 mm, the coil average diameter D is 18 mm when it is twisted 100° and compressed to 73%, the number of turns of the effective winding portion 41 is 2.5, and the number of turns of the end winding portion 42 is 1. It shows the measured value using the torsion spring. As explained above, the free state is the state in which no load acts on the torsion spring.

The graph shown in FIG. 6 is a graph of the interval (inner width) between the wire rods for each angle at which the measurement points in the circumferential direction change at intervals of 30° with the boundary position P as the reference around the spring axis C. It is. Therefore, when the outer end position of the end turn portion 42 is 0° as the angle of the measurement point, the adjacent angle in the direction along the spring axis C is 360° ("0°-360°"). description), it can be understood that the value obtained from the horizontal axis for the interval between the wire rods at 0° and 360° (the inner width: the interval at the boundary position P) is approximately “0”.

Thus, in the conventional torsion spring in a compressed and twisted state (compression + torsion), the wire rods in the range of about 150° to 210° in the winding direction of the wire rod from the end position of the end turn portion 42 The inner width (interval) of the wires is extremely short, and the wires are in a state where they are very likely to come into contact with each other. Specifically, the intermediate distance Gm between the wire rods at the first intermediate position Q1 and the second intermediate position Q2 indicated by 180°-540° in FIG. 6 is 0.008 mm, whereas 540° in FIG. The effective part gap Ga, which is the gap between the wire rods in the effective winding part 41 indicated by −900°, is 0.978 mm. That is, the intermediate portion spacing Gm is approximately "0", and the intermediate portion spacing Gm is only 0.008 times the effective portion spacing Ga.

On the other hand, in the torsion spring 40 of the present embodiment, the intermediate interval Gm between the wire rods at the first intermediate position Q1 and the second intermediate position Q2 is 0.272 mm, and the interval between the wire rods in the effective winding portion 41 is 0.272 mm. The effective portion interval Ga is 0.645. That is, the intermediate space Gm of the product of the present embodiment is larger than the intermediate space Gm of the conventional product, and the intermediate space Gm of the product of the present embodiment is 0.42 times the effective space Ga. . As described above, the torsion spring 40 of the present embodiment has a region including 150° to 210° from the boundary position P in the wire winding direction, as shown in the graph of FIG. The distance between the wire rods is widened, and it is difficult for the wire rods to come into contact with each other.

FIG. 7 is a graph in which the acceleration (vibration acceleration) acting on the conventional product and the product of the present embodiment is taken on the horizontal axis, and the noise when the wires come into contact with each other due to the action of the acceleration is taken on the vertical axis. showing. In this graph, an audible level L of 30 dB, at which the human sense of hearing can hear the noise level at a very low level, is shown.

As described above, in the torsion spring 40 of the present embodiment, the interval between the wire rods at predetermined positions set based on the boundary position P (intermediate portion interval Gm) is the interval between the wire rods in the effective winding portion 41 (effective portion interval By setting it to 0.42 times Ga), it is possible to satisfactorily suppress the generation of abnormal noise due to the contact between the wires. As a result, for example, even if the torsion spring 40 vibrates due to vibration of the vehicle body, the generation of abnormal noise is suppressed.

That is, when acceleration acts on the torsion spring 40 of the present embodiment and the torsion spring of the conventional product, the wires of both torsion springs may come into contact with each other and generate abnormal noise. 2, the noise level of the torsion spring 40 of the present embodiment does not exceed the audible level L (30 db that "sounds very soft").

[Another embodiment]
The present invention may be configured as follows other than the above-described embodiments (components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments).

(a) A torsion spring 40 (an example of a coil spring) is constructed by bending a wire rod at a plurality of locations so as to create an intermediate interval Gm. With such a configuration, the inner width (gap) can be easily managed as compared with the case where the wire rod is gently curved to create the intermediate gap Gm.

(b) As a torsion spring 40 (an example of a coil spring), an end turn portion 42 is formed only at one end, and an intermediate portion interval Gm is created corresponding to the portion where the end turn portion 42 is formed. A wire rod may be molded. As the torsion spring 40, the end turn portion 42 may be formed by winding a wire rod a plurality of times.

INDUSTRIAL APPLICABILITY The present invention can be used in a rotation angle detection device having a coil spring for returning rotation of a rotating member.

2 rotation angle sensor 30 rotating member 40 torsion spring (coil spring)
41 Effective winding portion 42 End winding portion A Housing P Boundary position X Rotation axis center

Claims (3)

a rotating member supported rotatably around a rotation axis with respect to the housing;
a rotation angle sensor for detecting a rotation angle when the rotation member is rotated from a reference posture to a rotation posture with respect to the housing;
a coil spring whose engaging portion at one end engages the rotating member and whose engaging portion at the other end engages the casing in order to return the rotating posture of the rotating member to the reference posture; with
The coil spring has an effective winding portion in which a wire rod is helically formed at a predetermined pitch, and an end winding portion formed at least one end of the effective winding portion,
The coil spring is twisted by a predetermined angle in the tension direction and compressed by a predetermined ratio based on a free state where no load is applied, and the boundary between the effective winding portion and the end turn portion is defined as a boundary position. , the inner width of the wire at a position separated by 180° from the boundary position in the winding direction to the effective winding portion and a position separated by 180° from the boundary position in the winding direction to the end turn portion is the effective It is set to 0.42 times or more of the inner width of the wire rods in the winding part,
The rotation angle detection device, wherein the coil spring is accommodated in the housing in the state described above. 2. A rotation angle detecting device according to claim 1, wherein said end turn portion is formed at both end positions of said effective turn portion. 3. The rotation angle detecting device according to claim 1, wherein said predetermined angle is 100 degrees and said predetermined ratio is 73 to 77%.

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