Angle position holding device

Abstract

To provide a novel angle position holding device 2 including a joint member 4 that can be integrally molded with powder metallurgy despite the fact that a female engagement part 16 and a male engagement part 18 are coaxially arranged in axially different positions.SOLUTION: A joint member 4 is provided with an annular thick wall part 21 in a corner part between an outer peripheral surface in the other side bearing part 14 including a male engagement part 18 and the other side surface in an axial direction of an intermediate plate 10 to which a female engagement part 16 and a proximal end of the male engagement part 18 are connected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an angular position maintaining device comprising a coupling member that connects an input side device and an output side device to each other, braking torque applying means that applies a required braking torque to the coupling member, and support means that supports the braking torque applying means. [Background technology]

[0002] Patent Document 1 listed below discloses an angular position holding device that is attached to a shaft that transmits rotational torque from an input device such as an electric motor to an output device such as a vehicle hatchback, and that allows the shaft to rotate against a required braking torque when rotational torque is input from the input device, but holds the shaft by the required braking torque when no rotational torque is input from the input device; in other words, the angular position of the output device is held even when the drive of the input device is stopped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6815567 Summary of the Invention [Problem to be solved by the invention]

[0004] In the angular position maintaining device disclosed in Patent Document 1, the shaft extending from the input side device is directly connected to the output side device. However, depending on the configuration of the input side device and the output side device, both the input side device and the output side device may have shafts for transmitting rotation. In this case, the two shafts are connected by the angular position maintaining device. In other words, the angular position maintaining device also functions as a coupling, and the shaft extending from the input side device and the shaft extending from the output side device are connected via the angular position maintaining device. Here, if the shaft extending from the input side device and the shaft extending from the output side device both have male engaged portions, the coupling member has female engaged portions that engage with the male engaged portions. If both shafts have female engaged portions, the coupling member has male engaged portions that engage with the female engaged portions. On the other hand, if the shaft extending from the input side device and the shaft extending from the output side device each have male engaged portions and female engaged portions, respectively, the coupling member has female engaged portions and male engaged portions that engage with the male engaged portions and female engaged portions. The female engaging portion and the male engaging portion are arranged coaxially.

[0005] Furthermore, the braking torque applying means provided in the angular position maintaining device disclosed in Patent Document 1 is a coil spring, which is attached to the outer peripheral surface of the inner ring, the inside of which is penetrated by the shaft. The inner ring rotates against the braking torque caused by the tightening force of the coil spring, i.e., the inner ring slides against the coil spring. For this reason, the inner ring must have considerable strength, including wear resistance, and is manufactured using powder metallurgy. The braking torque applying means is not limited to a coil spring, and leaf springs, so-called ring springs, etc., are also possible.

[0006] However, when the above-mentioned coupling member, i.e., a coupling member in which the female engaging portion and the male engaging portion are arranged coaxially, is used as the inner ring of the angular position maintaining device disclosed in Patent Document 1, the coupling member needs to be provided with a cylindrical portion for mounting a coil spring, and therefore the female engaging portion and the male engaging portion cannot be arranged at the same axial position on the same axis, but must be arranged at different axial positions on the same axis. The same applies when the braking torque applying means is not a coil spring. Therefore, such a coupling member includes an intermediate plate arranged perpendicular to the axial direction, a cylindrical one-side bearing portion extending axially from one axial side surface of the intermediate plate, and an other-side bearing portion extending axially from the other axial side surface of the intermediate plate, the one-side bearing portion and the other-side bearing portion having a common central axis, and the female engaging portion is formed on the inner peripheral surface of the one-side bearing portion, and the male engaging portion is formed on the outer peripheral surface of the other-side bearing portion.

[0007] To manufacture such joint parts integrally by powder metallurgy, a molding die M as shown in Fig. 6 is generally used. Explaining with reference to Fig. 6, the molding die M includes a die D that penetrates in the axial direction and whose inner peripheral surface defines the outer peripheral surface of the joint part P, a one-sided punch Pa that enters from one end of a through hole provided in the die D, a other-sided punch Pb that enters from the other end of the through hole provided in the die D, and an axial core C that is inserted inside the one-sided punch Pa and the other-sided punch Pb. The one-sided punch Pa further includes a one-sided outer punch Pa1 whose axial end face defines one axial end face of the one-sided bearing part Ba, and a one-sided inner punch Pa2 whose axial end face defines one axial side face of the intermediate plate MP and whose outer peripheral surface defines the female engaging part FE. The other-side punch Pb further includes an other-side outer punch Pb1 whose axial end face defines the other axial side surface of the intermediate plate MP and whose inner peripheral surface defines the male engaging portion ME, and an other-side inner punch Pb2 whose axial end face defines the other axial end face of the other-side bearing portion Bb. After powder material is filled inside the die D and the one-side punch Pa and the other-side punch Pb are combined as required, the one-side punch Pa and the other-side punch Pb are moved in directions approaching each other inside the die D, whereby the powder material filled inside the die D is compression-molded into the shape of the joint part P. At this time, because the distance between the outer peripheral edge of the one-side inner punch Pa2 and the inner peripheral edge of the other-side outer punch Pb1 when viewed in the axial direction is relatively short, there is a risk that load will be concentrated at the corner between the outer peripheral surface of the other-side bearing portion Bb and the other axial side surface of the intermediate plate MP, and at the corner between the inner peripheral surface of the one-side bearing portion Ba and one axial side surface of the intermediate plate MP, causing damage to the molding die M. Even if the molding die M is not damaged, there is a risk that the corners will break when the molded product removed from the molding die M is sintered.

[0008] The present invention has been made in view of the above circumstances, and its main technical object is to provide a new and improved angular position retaining device having a coupling member that can be integrally molded by powder metallurgy, even though the female engaging portion and the male engaging portion are coaxially arranged at different axial positions. [Means for solving the problem]

[0009] As a result of extensive research, the inventors have discovered that the above-mentioned main technical problem can be solved by providing an annular thick portion at the corner of the coupling member between the outer peripheral surface of the other bearing part having the male engaging portion and the other axial side surface of the intermediate plate to which the base ends of the female engaging portion and the male engaging portion are respectively connected.

[0010] That is, according to the present invention, there is provided an angular position holding device that solves the above-mentioned main technical problem, comprising a coupling member that interconnects an input side device and an output side device, braking torque applying means that applies a required braking torque to the coupling member, and support means that supports the braking torque applying means, wherein when rotational torque is input from the input side device, the coupling member rotates relative to the braking torque applying means against the required braking torque, and when rotational torque is not input from the input side device, the coupling member is held in position by the required braking torque, wherein: the coupling member includes an intermediate plate disposed perpendicular to the axial direction, a cylindrical one-side bearing portion extending in the axial direction from one axial side surface of the intermediate plate, and an other-side bearing portion extending in the axial direction from the other axial side surface of the intermediate plate, The intermediate plate, the one-side bearing portion, and the other-side bearing portion are integrally molded, the one-side bearing portion and the other-side bearing portion have a common center axis, and a female engaging portion is formed on an inner peripheral surface of the one-side bearing portion, and a male engaging portion is formed on an outer peripheral surface of the other-side bearing portion, The angular position maintaining device is characterized in that an annular thick portion is provided at a corner between the outer peripheral surface of the other-side bearing portion and the other axial side surface of the intermediate plate.

[0011] Preferably, the outer peripheral surface of the thick portion has a tapered shape that slopes radially inward toward the other axial side. Preferably, an auxiliary thick portion is provided inside the female engagement portion on one axial side of the intermediate plate. It is preferable that the intermediate plate and the other-side bearing portion have circular through-holes that communicate with the inside of the one-side bearing portion. It is preferable that the intermediate plate is disk-shaped, the one-side bearing portion is cylindrical and extends axially from the outer peripheral edge of the intermediate plate to one side, and the braking torque applying means is a coil spring disposed on the outer peripheral surface of the one-side bearing portion and / or the outer peripheral surface of the intermediate plate. Preferably, the support means is a fixed housing, and the braking torque applying means is accommodated inside the housing. Both the male engagement portion and the female engagement portion are preferably serrated or splined. In this case, it is preferable that the pitch circle diameters of the male engagement portion and the female engagement portion are approximately the same. [Effects of the Invention]

[0012] In the angular position-holding device constructed according to the present invention, annular thickened portions are provided at corners between the outer peripheral surface of the other-side bearing part having the male engaging part of the coupling member and the other axial side surface of the intermediate plate, and the outer peripheral surface of these thickened portions is defined by the inner peripheral edge of the axial tip surface of the other-side outer punch of the molding die, so that the outer peripheral edge of the axial tip surface of the one-side inner punch and the inner peripheral edge of the axial tip surface of the other-side outer punch are spaced apart, thereby mitigating the load acting on the powder material present therebetween.This prevents load concentration at the corners during compression molding, which could damage the molding die during molding, and prevents the corners from fracturing when the molded product is removed from the molding die and sintered. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing a preferred embodiment of an angular position maintaining device constructed in accordance with the present invention; [Figure 2] 2 is a view showing a joint member of the angular position maintaining device shown in FIG. 1 alone. FIG. [Figure 3] FIG. 2 is a view showing the housing of the angular position maintaining device shown in FIG. 1 alone. [Figure 4]3A to 3C are diagrams illustrating a process for forming the joint member shown in FIG. 2. [Figure 5] 5 is an enlarged view of a part of the diagram illustrating the compression step in FIG. 4. FIG. [Figure 6] FIG. 2 is a diagram showing a molding die for molding an embodiment of a joint member. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a more detailed description will be given with reference to the accompanying drawings showing preferred embodiments of an angular position maintaining device constructed according to the present invention. In the following description, the terms "one axial side" and "other axial side" refer to the left side and the right side in the state shown in the AA cross section of Figure 1, unless otherwise specified.

[0015] Referring to FIG. 1, an angular position maintaining device generally designated by the numeral 2 comprises a joint member 4, a braking torque applying means 6, and a support means 8.

[0016] The coupling member 4 connects a shaft S1 extending from either the input-side device or the output-side device with a shaft S2 extending from the other, allowing the shafts S1 and S2 to rotate integrally. The coupling member 4 is indicated by a rotation axis o. The coupling member 4 is integrally molded using powder metallurgy. The molding method will be described later. Referring to FIG. 1 and FIG. 2, the coupling member 4 includes an intermediate plate 10 (shown by a two-dot chain line in the cross-sectional view taken along line AA in FIG. 2) arranged perpendicular to the axial direction, a one-side bearing portion 12 extending axially from one axial side surface of the intermediate plate 10, and an other-side bearing portion 14 extending axially from the other axial side surface of the intermediate plate 10. The one-side bearing portion 12 and the other-side bearing portion 14 share a common central axis. This central axis is also the rotation axis o. A female engaging portion 16 is formed on the inner peripheral surface of the one-side bearing portion 12, and a male engaging portion 18 is formed on the outer peripheral surface of the other-side bearing portion 14. In the illustrated embodiment, the intermediate plate 10 is disk-shaped, and a circular through-hole 19 is formed in the intermediate plate 10 and the other-side bearing portion 14 in the axial direction, communicating with the inside of the one-side bearing portion 12. The through-hole 19 is formed in the center of the intermediate plate 10. The one-side bearing portion 12 is cylindrical and extends axially from the outer periphery of the intermediate plate 10 to one side. A ring-shaped support protrusion 20 extending circumferentially is formed on the outer periphery of one axial end face of the one-side bearing portion 12. The female engagement portion 16 and the male engagement portion 18 are both serrated and have approximately the same pitch circle diameter. In the illustrated embodiment, the pitch circle diameter of the female engagement portion 16 is slightly larger than the pitch circle diameter of the male engagement portion 18, the difference being 2.0%. The difference is preferably within 20%, more preferably within 10%. The female engaging portion 16 and the male engaging portion 18 are respectively engaged with a male engaged portion S1a consisting of serrations formed on the end of the shaft S1 and a female engaged portion S2a consisting of serrations formed on the end of the shaft S2. Here, in the angular position maintaining device constructed according to the present invention, it is important that an annular thick portion 21 is provided at the corner between the outer circumferential surface of the other-side bearing portion 14 of the coupling member 4 and the other axial side surface of the intermediate plate 10. In the illustrated embodiment, the outer circumferential surface of the thick portion 21 has a tapered shape that slopes radially inward toward the other axial side.In the illustrated embodiment, an auxiliary thick portion 22 is also formed on one axial side surface of the intermediate plate 10 inside the female engagement portion 16. The auxiliary thick portion 22 has an annular shape that surrounds the outer periphery of the through hole 19 and is spaced apart from the female engagement portion 16. The thick portion 21 and the auxiliary thick portion 22 will be described later together with the molding process of the joint member 4.

[0017] Referring to FIG. 1, in the illustrated embodiment, the braking torque application means 6 is a coil spring (hereinafter, the coil spring may be designated by the numeral 6), and includes a winding portion 23 in which a metal wire is wound in a spiral shape, and a pair of hook portions 24a and 24b where the wire extends radially outward from the winding portion 23. The pair of hook portions 24a and 24b are formed by both ends of the wire. Therefore, the pair of hook portions 24a and 24b are provided at both axial ends of the winding portion 23. When the coil spring 6 is in a free state, that is, when the coil spring 6 is not receiving any external force, the inner diameter of the winding portion 23 is smaller than the outer diameter of the one-side bearing portion 12 of the joint member 4, and the coil spring 6 is mounted in close contact with the outer peripheral surface of the one-side bearing portion 12 with the inner diameter of the winding portion 23 expanded. If desired, the coil spring 6 may be mounted on the outer peripheral surface of the one-side bearing portion 12 and / or the outer peripheral surface of the intermediate plate 10 .

[0018] In the illustrated embodiment, the support means 8 is a fixed housing, and the coupling member 4 and braking torque applying means (coil spring 6) are housed inside the housing. Referring to FIGS. 1 and 3, the housing is made of synthetic resin and includes a housing body 26 shown in FIG. 3(a) and a shield 28 shown in FIG. 3(b). The housing body 26 has a circular end plate 30 arranged perpendicular to the axial direction and a cylindrical outer peripheral wall 32 extending from the outer peripheral edge of the end plate to the other axial direction. A circular through-hole 34 is formed in the center of the end plate 30, penetrating it in the axial direction. Four arc-shaped retaining recesses 36 having a required circumferential width are formed circumferentially at intervals on the outer peripheral edge of one axial side of the end plate 30. A ring-shaped supported ridge 38 is formed on the other axial side of the end plate 30, surrounding the outer peripheral edge of the through-hole 34. The supported ribs 38 are positioned inside the supporting ribs 20 of the coupling component 4 to support them and also support one axial end surface of the coupling component 4. Six retaining grooves 40, each arc-shaped in cross section and extending linearly over the entire axial length, are formed on the outer circumferential surface of the outer circumferential wall 32 at equiangular intervals in the circumferential direction. The housing body 26 is fixed via the retaining recesses 36 and the retaining grooves 40. A pair of locking walls, each arc-shaped in cross section, are provided circumferentially spaced apart on the inner circumferential surface of the outer circumferential wall 32 (respective locking walls are designated 42a and 42b) extending axially from the other axial side surface of the end plate 30 to a required extent. A pair of gaps 44a and 44b are present between the pair of locking walls 42a and 42b. The inner circumferential surfaces of the pair of locking walls 42a and 42b face the outer surface of the wound portion 23 of the coil spring 6, and the pair of hook portions 24a and 24b are commonly fitted into the gap 44b. Thus, the coil spring 6 is supported in a state where it cannot rotate relative to the support means 8. An annular locking groove 46 extending in the circumferential direction is formed on the other axial end of the inner peripheral surface of the outer peripheral wall 32.

[0019] The shield 28 includes a circular shield plate 48 disposed perpendicular to the axial direction. A circular through-hole 50 is formed in the center of the shield plate 48, penetrating in the axial direction. One axial end of the other-side bearing portion 14 is inserted into the through-hole 50. An annular support wall 52 surrounding the outer periphery of the through-hole 50 is formed on one axial side of the shield plate 48. A cylindrical mounting wall 54 extending axially from the outer periphery is formed on the other axial side of the shield plate 48. A circular annular circumferential groove 56 opening toward the other axial side is formed in the mounting wall 54, and six ribs 57 are disposed equiangularly in the circumferential direction. A circular annular locking rib 58 extending in the circumferential direction is formed on the outer periphery of the mounting wall 54. The locking rib 58 is engaged with the locking groove 46 formed in the inner circumferential surface of the outer circumferential wall 32 of the housing main body 26, thereby assembling the shield 28 to the housing main body 26. In this way, one axial side surface of the shield plate 48 axially supports the other axial side surface of the intermediate plate 10 of the joint member 4, and the inner peripheral surface of the support wall 52 radially supports the outer peripheral surface of the intermediate plate 10.

[0020] The angular position maintaining device 2 operates as follows. Specifically, because the shaft S1, the coupling member 4, and the shaft S2 are integral, when rotational torque is input from the input-side device, the coupling member 4 attempts to rotate together with the coil spring 6. At this time, since the coil spring 6 cannot rotate relative to the support means 8 (housing) as described above, one of the pair of hook portions 24a and 24b is pressed relatively in a direction that loosens the coil spring 6 by the circumferential side surface of one of the pair of locking walls 42a and 42b within the gap 44b formed in the housing main body 26. As a result, the coupling member 4 rotates relative to the coil spring 6 against the required braking torque due to the tightening force of the coil spring 6. In other words, the rotational torque from the input-side device is transmitted to the output-side device, driving it. On the other hand, when rotational torque is not input from the input-side device, the coupling member 4 is maintained by the required braking torque of the coil spring 6. Thus, the angular position of the output-side device is maintained.

[0021] Next, the process of integrally molding the above-mentioned joint member 4 by powder metallurgy will be described with reference to Figures 4 and 5. Figure 4 shows an overall view of the molding process, and Figure 5 shows a view of the compression process shown in Figure 4.

[0022] First, a molding die 100 for molding the joint part 4 will be described with reference to Figure 5. The molding die 100 includes a die 102 penetrating in the axial direction, a one-sided punch 104 that enters a through hole provided in the die 102 from one end, a other-sided punch 106 that enters from the other end, and a shaft-shaped core 107 that is inserted inside the one-sided punch 104 and the other-sided punch 106. The inner peripheral surface of the die 102 defines the outer peripheral surface of the joint part 4, and the core 107 defines the through hole 19 of the joint part 4. The one-sided punch 104 further includes a one-sided outer punch 108 whose axial end face defines one axial end face of the one-sided bearing part 12, and a one-sided inner punch 110 whose axial end face defines one axial side face of the intermediate plate 10 and whose outer peripheral surface defines the female engagement part 16. The other-side punch 106 further includes an other-side outer punch 112 whose axial end face defines the other axial side surface of the intermediate plate 10 and whose inner peripheral surface defines the male engaging portion 18, and an other-side inner punch 114 whose axial end face defines the other axial end face of the other-side bearing portion 14. The axial tip face of the one-side outer punch 108 faces the axial tip face of the other-side outer punch 112, and the axial tip face of the one-side inner punch 110 faces the axial tip face of the other-side inner punch 114, and the one-side outer punch 108, the one-side inner punch 110, and the other-side outer punch 112, the other-side inner punch 114 can all advance and retreat relative to the die 102.

[0023] Next, with reference to FIG. 4, a process for molding a joint member 4 using a molding die 100 will be described. First, as shown in FIG. 4(a), a metal powder material P is filled inside the die 102. At this time, either the one-side punch 104 or the other-side punch 106 closes one end of the through hole provided in the die 102. In the illustrated embodiment, the other-side punch 106 first closes the other end of the through hole, and after the powder material P is introduced inside the die 102, the one-side punch 104 closes one end of the through hole as shown in FIG. 4(b). Next, from the state shown in FIG. 4(b), the one-side outer punch 108 and one-side inner punch 110 constituting the one-side punch 104 and the other-side outer punch 112 and other-side inner punch 114 constituting the other-side punch 106 each move as required without applying excessive pressure to the powder material P, thereby forming the space filled with the powder material P into a shape similar to that of the joint member 4 to be molded. This process is called transfer and is well known to those skilled in the art. Figure 4(c) shows the state after transfer. After the transfer is completed, as shown in Figure 4(d), the one-sided punch 104 and the other-sided punch 106 are moved toward each other inside the die 102, thereby compressing and molding the powder material P filled inside the die 102 into the shape of the joint part 4. Thereafter, as shown in Figure 4(e), the one-sided punch 104 and the other-sided punch 106 are moved relative to the die 102, and the compressed joint part green body 4' is removed. The removed joint part green body 4' is then sintered in an appropriate furnace to form the joint part 4.

[0024] Explaining with reference to Figure 5, in the angular position maintaining device constructed according to the present invention, an annular thick-walled portion 21 is provided in the coupling member 4 (4') at a corner between the outer peripheral surface of the other-side bearing portion 14 having the male engaging portion 18 and the other axial side surface of the intermediate plate 10, and the outer peripheral surface of this thick-walled portion 21 is defined by the inner peripheral edge of the axial tip surface of the other-side outer punch 112 of the molding die 100. As a result, the outer peripheral edge of the axial tip surface of the one-side inner punch 110 and the inner peripheral edge of the axial tip surface of the other-side outer punch 112 are spaced apart, and the load acting on the powder material P present therebetween is alleviated. This prevents the molding die 100 from being damaged by a load concentrated at the corner during compression molding, and prevents the corner from breaking when the coupling member green body 4' (molded product) removed from the molding die 100 is sintered. Thus, an angular position-holding device including a coupling member 4 that can be integrally molded by powder metallurgy is obtained, even though the female engaging portion 16 and the male engaging portion 18 are coaxially positioned at different axial positions. In the illustrated embodiment, the outer peripheral surface of the thick-walled portion 21 is tapered, inclining radially inward toward the other axial side, allowing the other-side outer punch 112 to be easily released from the mold. Furthermore, in the illustrated embodiment, an auxiliary thick-walled portion 22 is provided inside the female engaging portion 16 on one axial side of the intermediate plate 10. This increases the volume near the corner, further reducing the load acting on the corner during compression molding. The auxiliary thick-walled portion 22 supports and positions the other axial end face of the shaft S1. Because the outer peripheral edge of the other axial end face of the shaft S1 is usually chamfered, it is preferable that the auxiliary thick-walled portion 22 be positioned relatively radially inward, away from the female engaging portion 16.

[0025] The angular position maintaining device constructed according to the present invention has been described above in detail with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiment, and appropriate modifications and variations are possible without departing from the spirit and scope of the present invention. For example, in the illustrated embodiment, both the female engaging portion 16 and the male engaging portion 18 are serrated, but they may be splines. Furthermore, since the braking torque applying means is required to apply the required braking torque to the coupling member, it is not limited to a coil spring and can be replaced by various means such as a leaf spring or a ring spring. Furthermore, since the support means is required to support the braking torque applying means, it is not necessarily limited to a housing. If the braking torque applying means is a coil spring, the support means may be, for example, an appropriate catch portion that supports a pair of hooks. [Explanation of symbols]

[0026] 2: Angle position holding device 4: Joint material 6: Braking torque applying means (coil spring) 8: Support means (housing) 10: Intermediate plate 12: One-sided bearing part 14:Other side bearing part 16: Female engagement part 18: Male engagement part 21:Thick part 22: Auxiliary thick part

Claims

1. An angular position maintaining device comprising a coupling member connecting an input side device and an output side device to each other, braking torque applying means for applying a required braking torque to the coupling member, and support means for supporting the braking torque applying means, wherein when rotational torque is input from the input side device, the coupling member rotates relative to the braking torque applying means against the required braking torque, and when rotational torque is not input from the input side device, the coupling member is maintained in position by the required braking torque, The coupling member comprises an intermediate plate arranged perpendicular to the axial direction, a cylindrical one-side bearing portion extending in the axial direction from one axial side surface of the intermediate plate, and an other-side bearing portion extending in the axial direction from the other axial side surface of the intermediate plate, the intermediate plate, the one-side bearing portion, and the other-side bearing portion being molded integrally, the one-side bearing portion and the other-side bearing portion having a common central axis, a female engaging portion formed on an inner peripheral surface of the one-side bearing portion, and a male engaging portion formed on an outer peripheral surface of the other-side bearing portion, an annular thick portion is provided at a corner between the outer peripheral surface of the other-side bearing portion and the other axial side surface of the intermediate plate;

2. 2. The angular position maintaining device according to claim 1, wherein the outer peripheral surface of the thick portion has a tapered shape that is inclined radially inward toward the other axial side.

3. 2. The angular position maintaining device according to claim 1, wherein an auxiliary thick portion is provided inside the female engagement portion on one axial side surface of the intermediate plate.

4. 2. The angular position maintaining device according to claim 1, wherein the intermediate plate and the other-side bearing portion are formed with a circular through-hole that communicates with the inside of the one-side bearing portion.

5. 2. The angular position maintaining device according to claim 1, wherein the intermediate plate is disk-shaped, the one-side bearing portion is cylindrical and extends axially from the outer peripheral edge of the intermediate plate to one side, and the braking torque applying means is a coil spring disposed on the outer peripheral surface of the one-side bearing portion and / or the outer peripheral surface of the intermediate plate.

6. 2. The angular position maintaining device according to claim 1, wherein said support means is a fixed housing, and said braking torque applying means is accommodated inside said housing.

7. 2. The angular position maintaining device according to claim 1, wherein both the male engaging portion and the female engaging portion are serrations or splines.

8. 8. The angular position maintaining device according to claim 7, wherein the pitch circle diameters of the male engaging portion and the female engaging portion are approximately the same.

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