JPH08218445A - Joint structure of angle detector - Google Patents

Abstract

PURPOSE: To provide a joint structure which is inexpensive, small-sized, easy in assembling and simple in adjustment in an angle detector for detecting the relative angle of a front angle attended with the actuation of a power shovel or the like. CONSTITUTION: About semicircular slots 111,112 which extend axially centering around an opening hole 110 and its edge and symmetrically about an axial center are provided coaxially to the central hole 502 of a main body 500 which can be attached to the attaching face of the front member of a working machine on the side opposite to an attached lever of a rotary shaft 100 where a lever for transmitting the relative angle of a front member can be attached at its one end. Both the ends of a U-shape plate-shaped spring member 200 are inserted in slots 111, 112 so that its parallel part may be axially parallel, and the width across flat part of the detector shaft 301 of a rotary angle detector 300 is fittedly inserted in the above parallel part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure of an angle detector which is provided in a construction machine such as a power shovel and detects a relative angle of a front angle when the working machine operates.

[0002]

2. Description of the Related Art Generally, a construction machine, for example, a small excavator, is equipped with an angle detector for detecting a relative angle of a front angle. The angle detector used for such a construction machine is required to faithfully transmit the rotation angle transmitted from the front lever to the rotation shaft to the potentiometer or the like. Further, it is required to reduce the height of the angle detector so that the angle detector does not protrude as much as possible so that the work tool and other objects do not collide. However, the strength of the rotation angle detector itself, such as a potentiometer for detecting the rotation angle, is generally weak, so the joint structure was designed so that it would not be mechanically difficult during manufacture and assembly. Also,
Since the rotation angle detector rotation shaft is not directly connected to the lever of the front member in terms of strength, only the rotation angle can be transmitted through a joint or the like.

For example, in Japanese Utility Model Laid-Open No. 3-99304, as shown in FIGS. 11 and 12 which is a view taken along the line EE in FIG. 11, the rotation of a rotary shaft 31 to which a lever 37 for transmitting a relative angle is attached. Connection-side end face portion 31a of the angle detector 33
A groove portion 31b that passes through the axis of the rotary shaft is formed, an elastic clamp 32 having a substantially U-shaped side view is provided in the groove, and the shaft 33a of the rotation angle detector is inserted into the elastic clamp. Discloses that only the angle is transmitted to the axis of the rotation angle detector. The rotating shaft 31 is supported by a rolling bearing 36 attached to the body 35, and the rotation angle detector 33 is attached to the body 35 and the mounting body 34.
It is covered with.

Further, in Japanese Utility Model Laid-Open No. 4-17455, as shown in FIG. 13, an arm 4 supporting both ends of a rotary shaft 41 is provided.
7, the strength is strengthened, and the groove 41a at the end of the rotary shaft, the joint member 42 having concave and convex portions orthogonal to each other at both ends, and the rod-shaped elastic member 49 attached to the shaft 33a of the rotation angle detector 33 are Oldham. The joint is configured so that only the angle of the rotation axis is transmitted to the axis of the rotation angle detector,
The rotation angle detector is supported by the elastic support member 46 and the case 4
It is mounted on the arm body so as to be housed in the arms 4 and 45 and partially buried in the arm 47.

Further, in Japanese Unexamined Patent Publication No. 6-316948, as shown in FIGS. 14 and 15 which is a view taken along the line FF of FIG. 14, from the inner end surface of the rotary shaft 51, along the axial center thereof. A fitting hole 51a is formed, and a rubber coupling 52 is fitted and fixed in the fitting hole, and an engagement hole 52a having a D-shaped cross section is formed in the shaft center of the coupling 52. On the other hand, the detection shaft 53a of the potentiometer 53, which is a rotation angle detector, is formed in a D-shaped cross section, and the detection shaft 53a is provided with the engagement hole 52a.
By inserting and engaging with the
The rotation shaft 51 and the detection shaft 53a are integrally rotatable.

However, in Japanese Utility Model Laid-Open No. 3-99304, as shown in FIG. 12, the dimension in the axial direction is small, but the parallel hole 31b is provided in the rotary shaft, so that the machining is difficult. Furthermore, although the axial misalignment between the rotation shaft 31 and the detection shaft 33a of the rotation angle detector 33 is absorbed by the substantially U-shaped elastic clamp 32 in the twisting direction, U from the parallel hole 31b.
Stopper 3 to prevent falling of the elastic gripping tool
Need 8 Therefore, there is a possibility that the elastic clamp 32 is mechanically unreasonable due to the tolerance of the stopper position and the width W of the elastic clamp 32. Also, a U-shaped elastic clamp 32
Has a complicated shape, and there are problems such as dimensional control as parts and mold costs until the shape is fixed.

Further, in Japanese Utility Model Laid-Open No. 4-17455,
As shown in FIG. 13, the strength is strong and the radial direction can be made small, but the axial dimension becomes excessively large, and it is difficult to process the concave portion of the joint member 42 or the concave portion of the rotary shaft end portion 41a. If so, there was a problem such as occurrence of hysteresis.

[0008]

On the other hand, JP-A-6-31
In the 6948, as shown in FIG. 14, the hysteresis is small and the radial and axial dimensions can be reduced,
Equipment and a mold are required to manufacture the rubber coupling 52 that fits into the fitting hole 51a, and since the material is rubber, there is a possibility that powdery solidification or deterioration such as cracking may occur due to the aging of the rubber. However, there was a problem in strength and the need for handling and repairing, that is, maintenance management.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to facilitate processing, to easily adjust the assembling, and to measure the radial and axial dimensions. The present invention aims to provide a joint structure for an angle detector that is small in size and does not have insufficient strength or deterioration over time.

[0010]

In order to achieve the above object, according to the present invention, there is provided an angle detector for detecting a relative angle of a front member forming a working machine, the angle detector being mounted on a mounting surface of the front member. A main body, a rotary shaft rotatably provided in a central hole of the main body, to which a lever for transmitting a relative angle of the front member can be attached, and a concentric axis of the rotary shaft. In the angle detector having a rotation angle detector attachable to the main body, the rotation shaft is provided with an opening hole which is concentric with the rotation shaft and opens on the side opposite to the lever mounting side. Two slotted holes extending substantially in the axial direction and having a substantially semicircular or semielliptical cross section are provided with the opposite hole edges centering on the central axis of the opening hole.

A plate-like member having a substantially constant axial width across the two groove holes, and both ends thereof are inserted (inserted) or loosely inserted (inserted with a gap) into the outer periphery of the groove hole. A spring member having a parallel portion extending parallel to the slot with the axis of rotation interposed therebetween is provided. Further, a rotation angle detector with a rotation detector shaft is provided which has a width across flats which is larger than the width of a pair of opposing parallel parts of the spring member in a state of being inserted or loosely fitted in the slot. Then, the two-width portion is sandwiched by the parallel portions of the spring member so that the spring member is fixed in the slot. The axial distance between the body-side end of the flat width portion and the bottom of the slot is slightly larger than the axial width of the spring member.

The spring member may have a substantially U-shaped cross section.

The spring member may be a combination of two substantially L-shaped cross sections in the shape of a square.

The spring member may be a combination of two substantially U-shaped cross-sections in a square shape.

It is more reliable if the spring member is substantially oval and one end of the oval end is separated.

[0016]

According to the above, the spring member inserted across the slot in the rotary shaft is locked in the slot by the spring force and fixed in the rotary shaft, or slightly without the spring force. It is inserted with a gap of. Since the opposing distance of at least the axial center of the parallel portion of the spring member is made slightly smaller than the width of the width across flats machined parallel to the shaft end of the rotation detecting shaft, the shaft end of the rotation angle detector is When the surface width portion is sandwiched between the parallel portions of the spring member, a spring force that expands outward is generated in the spring member. Therefore, when the spring member is inserted into the groove hole, it is more firmly fixed, and when the spring member is loosely fitted into the groove hole, a part or all of the both ends of the spring member is not covered with the groove wall or groove. It is fixed to the hole edge by spring force. Then, the rotation shaft, the spring member, and the shaft end width across flats of the rotation detection shaft are fixed by the spring force, and the play is eliminated. When the rotation axis and the rotation detection axis are eccentric, the eccentricity in the direction parallel to the spring member parallel part is absorbed by the relative sliding between the parallel parts of the spring member and the width across flats, and the other direction. Is absorbed by the deformation of the parallel portion of the spring member. Therefore, no mechanical strain is applied to each component. In addition, the misalignment is absorbed and the angle of the rotation shaft is smoothly transmitted to the rotation detector via the rotation detection shaft with no play.

Further, the spring member is provided with a slight gap so that one end in the axial direction can come into contact with the bottom of the slot and the other can come into contact with the main body side end of the width across flats of the rotation detecting shaft. Therefore, the spring member is sandwiched between the bottom of the groove and the end portion of the width across flats with a slight gap, and the spring member is not greatly inclined or separated from the groove.

Upon assembly, the spring member is pushed into the groove of the rotary shaft, and the two-width portion of the rotary detection shaft of the rotary angle detector is inserted into the parallel part of the spring member to mount the rotary angle detector. Only then, concentric fitting is performed. Further, in processing, since the opening hole and the slot hole provided in the rotary shaft are basically circular, they can be processed by a drill or an end mill.

If the spring member has a substantially U-shaped cross section, a U-shaped semicircular portion is fitted into one groove hole properly, and the tip end is brought into contact with the outer circumference of the groove hole at the other end so that the spring member is parallel to the groove. When the width across flats of the angle detector is clamped, a spring force is generated.

If the spring member has a substantially L-shaped cross-section, the short piece side is slightly smaller than the slot hole diameter, and the long piece side is an L-letter shape with a dimension between the opening hole diameter and the distance between both slot holes. It is easy, and if these two are combined in a square shape, the same operation as the U-shaped one can be performed.

If the cross section of the spring member is substantially U-shaped, the positions can be secured with respect to each other, so that the spring member is more stable during assembly than the L-shaped one.

If the spring member is formed into a substantially oval shape and one end of the oval end portion is separated, the both ends are fitted into the groove hole portion,
Position is stable and spring force is also stable. It should be noted that if the spring force is applied in advance so as to spread outward before the spring member is assembled in the groove hole, it will be fixed to some extent even when the spring member is assembled in the groove hole, so it is easy to assemble. Become.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a main part showing a first embodiment of the present invention, FIG. 2 is an exploded perspective view of FIG. 1, FIG.
FIG. 4 is a view on arrow AA of FIG. 3. 1 and 2,
Mounting hole 50 that can be attached to a boom (not shown) with bolts
The plain bearing 6 is fitted in the center hole 502 of the main body 500 having the number 1. The rotary shaft 100 is rotatably inserted into the slide bearing 6, and a small diameter portion 101 to which a boom lever (not shown) is attached is provided at the shaft end of the rotary shaft 100 protruding from the main body 500 to prevent relative sliding with the lever. A key 7 for preventing is attached to the key groove 102. An opening hole 110 is formed in the other end of the rotary shaft 100 along the center of the rotary shaft. Two slots 11 having a semi-elliptical cross section centered on opposite hole edges around the center axis of the opening hole 11
1, 112 are provided along the axial direction of the wall surface of the opening.

A collar 103 is provided on the outer periphery of the other end of the rotary shaft 100.
Is provided, and the main body side 104 of the collar 103 is the main body 5
The sliding surface 503 of 00 is slidable. The adjustment plate 400 sandwiches the collar 103 with the main body 500, and the bolt 1
The end surface side 105 of the flange 103 of the rotary shaft 100 is slidably abutted on the adjusting plate. The adjustment plate 400 is provided with a cocoon-shaped elongated hole 401 through which the bolt 13 penetrates, and the main body 500 and the adjustment plate 400 can be attached at a fixed angle within a certain range. The central hole 402 of the adjusting plate 400 is the central hole 502 of the main body 500.
And a small diameter portion 302 of the rotation angle detector 300.
Has been inserted. By rotating the mounting bolt 12 into the screw hole 403 of the adjusting plate 400, the rotation angle detector 300
Is fixed to the adjusting plate 400.

As shown in FIGS. 3 and 4, the spring member 200, which is a plate-shaped material having elastic force, such as spring steel, and has a U-shaped cross section, is provided with the groove holes 111 and 11 in the rotary shaft.
Two ends of which are loosely fitted and accommodated in the No. 2. The outer diameter 202 of the circular portion of the U-shaped portion is made slightly smaller than the diameter of the slot 111.112, and the tip of the opposite side 203 abuts on the slot wall or is housed with a slight gap. Width across flats of rotation detection shaft 301 H
Is the inner dimension X of the parallel portion 201 of the spring member 200.
It is made slightly larger, and the width across flats of the rotation detection shaft 301 is sandwiched by the spring force inside the parallel portion near the axial center of the spring member 200. Also, the rotation detection shaft 30
1 is provided with a tapered tip portion 303, and the tip width L is the inner dimension X of the parallel portion 201 of the spring member 200.
It is made smaller and the insertion of the width across flats of the rotation detection shaft 301 into the spring member 200 is facilitated.

Next, the operation of the first embodiment will be described. When the width across flats of the rotation detecting shaft 301 is inserted into the spring member 200, the width across flats is larger than the width across the parallel portion 201 of the spring member. The spring member 200 spreads in the P and Q directions shown by the arrows in FIGS. 3 and 4, and accordingly, the slot holes 111 and 112 of the rotary shaft and the boundary points 121, 122, 123, and 124 with the opening hole 110 come into contact with each other for mounting. There is no play. Further, the spring member 200 and the width across flats of the rotation detecting shaft 301 are located near the corners across the width across flats 204, 20.
Contact is made at four points 5, 206, 207, and ideally eight points are supported together with the above-mentioned four points. Further, the length of the spring member in the radial direction may be such that at least an appropriate spring force is applied to the sum of the radial depth of the slot for locking the spring member and the shaft diameter of the rotation angle detector shaft. The radial dimension can be reduced. In addition, in the drawings referred to in the present embodiment and the embodiments described later, in actuality, as described above, the groove and the spring member are partially contacted with each other, but a gap is provided for the sake of explanation. There is.

Further, even if the rotation detection shaft 301 attached to the adjusting plate 400 and the axis of the rotation shaft are slightly displaced when assembled,
The P and Q directions are absorbed by the spring effect of the spring member. On the other hand, the directions of the arrows M and N are adjusted by an appropriate spring force, and the axial misalignment is absorbed by the relative sliding of the spring member and the widthwise flat portion of the rotary shaft. Even if the spring member 200 shifts in the direction of the arrow M or N in the rotation shaft 100, the rotation accuracy of the rotation detection shaft is hardly affected. With respect to the deformation in the twisting direction, the angle transmission accuracy is set within a practical range in consideration of the thickness and width of the spring member together with the direction of the arrow M or N. Therefore, the connection between the rotation detection shaft 301 and the rotation shaft 100 has no mechanical play. The spring member 200 forms a step portion 304 at the body-side end portion of the width across flats provided on the rotation detection shaft,
The spring member 200 is housed with a slight gap between the step portion 304, the groove holes 111 and 112, and the bottom portion 113 so that the spring member 200 is not displaced or slipped out in the axial direction due to vibration or impact. Therefore, the rotation detection shaft 30
It is possible to make the depth of the rotary shaft opening hole as small as possible to the very end of the first tip 305.

The features of the entire first embodiment will be described. In operation, when the rotating shaft 100 is rotated by a lever (not shown), the rotation angle detector 300 is rotated by the spring member 200 housed in the rotating shaft. The shaft rotates, and the rotation angle detector outputs a signal corresponding to the rotation angle.
The ring 11 seals the lever side and the rotation angle detector side to prevent dust and the like from entering. Further, since the rotation angle detector 300, the spring member 200, and the rotary shaft 100 can be configured with the adjustment plate 400 as a reference, the rotation angle detector 300 with the adjustment plate 400 as a reference before mounting the main body during assembly. The rotary shaft accommodating the spring member 200 can be assembled, the assembly and the position adjustment of the rotation angle detector are facilitated, the concentricity between the respective parts is easily obtained, and the angle detection accuracy is high. Furthermore, since the adjustment after mounting the main body is only the positional adjustment between the adjusting plate 400 and the main body 500, it is easy to secure the quality.

Further, a spring member 200 is provided in the rotary shaft, and a flange 103 provided at an end of the rotary shaft 100 is attached to the main body 50.
Since it is sandwiched between 0 and the adjusting plate 400 to receive the axial load, it is strong and compact. Further, by using the slide bearing 6, it is made smaller and has higher strength. Further, when some external force is applied to the lever or the like, the external force in the axial direction is received by the adjusting plate 400 or the main body sliding portion 503 via the flange portion 103 of the rotating shaft 100. Also,
External force in the direction perpendicular to the axis is applied to the sliding bearing portion 6 on the outer periphery of the rotary shaft 100.
It is supposed to be received at. Further, the rotation angle detector 300 is protected from external force, rain, etc. by burying the main body in the opening of the frame or by separately providing a mounting main body cover as in the conventional case.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is an explanatory view of a main part of the second embodiment of the present invention, and FIG. 6 is a view taken along the line BB of FIG. In the second embodiment, the U-shaped spring member 2 shown in the first embodiment is used.
Instead of 00, the spring member 220 is made up of two L-shaped spring members 221 and 222 that are easier to process. As in the case of FIG. 3, deviations in the directions of arrows M or N are made so that they can slide with respect to each other so that mechanical strain on the rotation angle detector shaft 301 can be absorbed.
Further, the L-shaped spring members 221 and 22 facing each other.
Even if 22 is displaced in the direction of arrow P or Q, the parallel portion of the rotation detecting shaft of the rotation detector fits, so that it is securely locked in the slot. The L-shaped spring member is so dimensioned that the end on the short piece side abuts the side surface on the long piece side on the mating side when it is assembled, and it is prevented from falling off from the slot.

A third embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is an explanatory view of essential parts of a third embodiment of the present invention, and FIG. 8 is a view taken along the line CC of FIG. In the third embodiment, the L-shaped spring member 22 shown in the second embodiment is used.
Instead of 0, U-shaped spring members 231 and 232 are used. In the case of the second embodiment, although it can be manufactured at a low cost, when a single spring member is assembled, the spring member moves due to no dimensional regulation or spring force, and the spring member is apt to fall off or get caught. In view of this, in the third embodiment, even a single U-shaped spring member is stably inserted into the slot, so that even if there is some shaking, it is unlikely to fall off. Further, after the two spring members are set and attached, the square shape is maintained, and the rotation angle detector shaft 301 can be easily inserted into the U-shaped spring member 230.

Further, FIG. 9 shows the fourth embodiment of the present invention.
And FIG. 10 will be described. FIG. 9 is an explanatory view of a main part of the fourth embodiment of the present invention, and FIG. 10 is a view taken along the line DD of FIG.
In the fourth embodiment, the U-shaped spring member 200 shown in the first embodiment is replaced by a substantially oval spring member 240, and the split groove 243 is formed at one end of the oval end portions 241 and 242.
Are separated by. Oval spring member 240
The shape of the bent portions 241 and 242 at both ends of the
The semicircular portion 12 has a circular shape similar to that of the semicircular portion 12 and can be fitted in the slot with a small gap in the longitudinal direction. Therefore, since the bent portions 241 and 242 at both ends are fitted in the slot holes properly, the spring member 240 is indicated by an arrow M.
Alternatively, the deviation in the N direction is small. Therefore, the fitting contact position between the rotation detection shaft 301 and the spring member 240 can be set at a fixed position, and stable rotation can be transmitted without a change or nonuniformity of the spring force due to the displacement of the spring member. Also, since the fixing of the spring member is stable,
Even if there is shock or vibration, there is no slight wear.

In the joint structure of the angle detector constructed as described above, it may be considered that only the spring member is housed (inserted) in the rotary shaft, and the rotary shaft itself can be easily processed. When the spring member is housed (inserted) in the rotary shaft, the spring effect (spring force) can be used for assembly, so that there is no problem even if the shaft center or concentricity is slightly displaced. Further, since the rotating shaft, the spring member, and the shaft width across flats of the rotation detecting shaft are fixed by the spring force, there is no play, and the eccentricity between the rotating shaft and the rotation detecting shaft is absorbed by the spring force of the spring member. Because it is done, there is little hysteresis and the accuracy is high.

Further, since the opening hole and the slot hole provided in the rotary shaft are circular, they can be formed by drilling or the like.
Further, in the case of end milling, the axial length can be further shortened, and the bottom can be made flat accordingly, and the rotating shaft length can be further shortened. Further, if a spring force is applied to the spring member so that the spring member expands outward, when the spring member is assembled into the groove hole, for example, the U-shaped open side 203 of the spring member 200 is slightly narrowed so that the spring force is increased. Since the holes can be fitted and inserted into the both groove holes 111 and 112 so as to be caught by the hole wall, the position of the spring member is stable in the groove hole, the spring force is also stable, and the subsequent rotation detection shaft is also assembled. It will be easier. In the embodiment, the example in which the present invention is used for the rotation angle detector including the adjusting plate 400, the slide bearing 6, etc. is shown. However, even in the case of a conventional angle detector, the present invention is applied to the joint portion thereof. It goes without saying that it can be applied.

[0035]

Since the present invention is configured as described above, it has the following effects.

Since the openings and slots provided in the rotary shaft are basically circular, they can be processed with a drill or end mill,
The spring member has a simple shape such as a U-shape, an L-shape, a U-shape, and an oval shape, and the manufacturing cost can be minimized and the manufacturing cost can be reduced.

If both ends of the spring member are housed (inserted) in the groove in the rotary shaft in advance until they come into contact with the bottom of the groove, and the rotation angle detector shaft is inserted so as to be sandwiched by the joint member. As it is good, the assembly is easy.

Since the spring member is supported in the radial groove in the rotary shaft in the direction perpendicular to the axis, at least the radial dimension is the distance between the groove holes and the radial length of the width across flats of the rotary shaft. However, since the axial length of the opening can be shortened to the rotational shaft length, the radial and axial dimensions are small. Further, in terms of material, spring steel or the like can be used for the spring member, so that the joint structure of the angle detector can be provided without insufficient strength or deterioration over time.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is an explanatory view of a main part of the first embodiment of the present invention.

FIG. 4 is a view taken along the line AA of FIG.

FIG. 5 is an explanatory view of a main part of a second embodiment of the present invention.

6 is a view taken along the line BB of FIG.

FIG. 7 is an explanatory view of a main part of a third embodiment of the present invention.

FIG. 8 is a view taken along line CC in FIG. 7;

FIG. 9 is an explanatory view of a main part of a fourth embodiment of the present invention.

FIG. 10 is a view taken along the line DD of FIG.

FIG. 11 is a sectional view of a main part of a conventional angle detector.

12 is a view taken along the line EE of FIG.

FIG. 13 is a sectional view of a main part of a conventional angle detector.

FIG. 14 is a sectional view of a main part of a conventional angle detector.

FIG. 15 is a view taken along the line FF of FIG.

[Explanation of symbols]

 100 Rotating Shaft 110 Opening Holes 111, 112 Groove Holes 113 Bottom 200 Spring Member (U-shaped) 201 Spring Member Parallel Part 220 Spring Member (L-shaped) 230 Spring Member (U-shaped) 240 Spring Member (substantially Oval) 300 Rotation Angle Detector 301 Rotation angle detector Shaft (width across flats) 304 Step 500 Main body 502 Main body center hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Nishimura 650 Jinritsucho, Tsuchiura City, Ibaraki Prefecture Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd. Company Toyo Company

Claims (5)

[Claims] 1. An angle detector for detecting a relative angle of a front member forming a working machine, the main body being attachable to a mounting surface of the front member, and rotatably provided in a center hole of the main body. Angle detection having a rotation shaft, one end of which is attached with a lever for transmitting the relative angle of the front member, and a rotation angle detector, which is attached to the main body concentrically with the axis of the rotation shaft. In the container, the rotating shaft extends in the axial direction about an opening hole that is concentric with the rotating shaft and opens on the side opposite to the lever mounting side, and a hole edge portion that opposes the opening hole central axis, and extends approximately in a semicircle or semicircle. It has two slotted holes with an oval cross section, both ends of which are inserted or loosely fitted into the slotted holes and has a plate-like shape with a substantially constant axial width, and faces the slotted holes in parallel across the axis of rotation. Between the spring member and the parallel part of the spring member And a rotation detection shaft of a rotation angle detector having a width across flats that is larger than the width of one side of the parallel portion of the spring member before being sandwiched and assembled, and the spring member is fixed in the groove hole. So that the width across flat portion is sandwiched between the parallel portions of the spring member, and the axial distance between the body-side end of the width across flat portion and the bottom of the slot is greater than the axial width of the spring member. The joint structure of the angle detector is characterized in that it is assembled slightly larger. 2. The joint structure for an angle detector according to claim 1, wherein the spring member has a substantially U-shaped cross section. 3. The joint structure for an angle detector according to claim 1, wherein the spring member is a combination of two substantially L-shaped cross sections in a square shape. 4. The joint structure for an angle detector according to claim 1, wherein the spring member is a combination of two substantially U-shaped sections in a square shape. 5. The joint structure for an angle detector according to claim 1, wherein the spring member has a substantially oval shape and one end of an oval end is separated.