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 holding device including a joint member that interconnects an input-side device and an output-side device, a braking torque applying means that applies a required braking torque to the joint member, and a support means that supports the braking torque applying means.

Background Art

[0002] Patent Document 1 below discloses a device that is mounted on a shaft for transmitting rotational torque from an input-side device such as an electric motor to an output-side device such as a hatchback of a vehicle. When rotational torque is input from the input-side device, the shaft is allowed to rotate against a required braking torque, while when no rotational torque is input from the input-side device, the shaft is held by the required braking torque, that is, the angular position of the output-side device is held even when the driving of the input-side device is stopped. An angular position holding device is disclosed.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the angular position holding device disclosed in the above Patent Document 1, the shaft extending from the input-side device was directly connected to the output-side device. However, depending on the configurations of the input-side device and the output-side device, there may be cases where both the input-side device and the output-side device are provided with shafts for transmitting rotation. In this case, the two shafts are connected by the angular position holding device. That is, the angular position holding device also functions as a joint, and the shaft extending from the input-side device and the shaft extending from the output-side device are connected via the angular position holding device. Here, when both the shaft extending from the input-side device and the shaft extending from the output-side device are provided with male engaged portions, the joint member is provided with a female engaged portion that engages with the male engaged portion. When both shafts are provided with female engaged portions, the joint member is provided with a male engaged portion that engages with the female engaged portion. On the other hand, when the shaft extending from the input-side device and the shaft extending from the output-side device are respectively provided with male and female engaged portions, the joint member is provided with female and male engaged portions that engage with the male and female engaged portions. The female engaged portion and the male engaged portion are arranged coaxially.

[0005] Also, the braking torque applying means included in the angular position holding device disclosed in the above Patent Document 1 is a coil spring, which is mounted on the outer peripheral surface of an inner ring through which the above shaft passes inside. And the inner ring rotates against the braking torque caused by the tightening force of the coil spring, that is, the inner ring slides relative to the coil spring. Therefore, the inner ring needs to have a considerable strength including wear resistance and is manufactured by powder metallurgy. The braking torque applying means is not limited to a coil spring, and there may also be a leaf spring or a so-called ring spring, etc.

[0006] Incidentally, when using the above-described joint member, that is, the joint member in which the female engaging portion and the male engaging portion are coaxially arranged respectively, as the inner ring of the angular position holding device disclosed in Patent Document 1, since it is necessary to provide a cylindrical portion for mounting a coil spring on the joint member, the female engaging portion and the male engaging portion cannot be arranged at the same position in the axial direction on the same axis, and it is necessary to arrange them at different positions in the axial direction on the same axis. The same applies when the braking torque applying means is other than a coil spring. Therefore, such a joint member includes an intermediate plate arranged perpendicular to the axial direction, a cylindrical one-sided bearing portion extending axially from one axial side surface of the intermediate plate, and the other axial bearing portion extending axially from the other axial side surface of the intermediate plate. The one-sided bearing portion and the other axial bearing portion have a common central axis, a female engaging portion is formed on the inner peripheral surface of the one-sided bearing portion, and a male engaging portion is formed on the outer peripheral surface of the other axial bearing portion respectively.

[0007] In order to integrally manufacture such a joint member by powder metallurgy, it is common to use a molding die M as shown in FIG. 6. Referring to FIG. 6 for explanation, such a 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 member P, a one-sided punch Pa that enters from one end of the through-hole provided in the die D, a the other-sided punch Pb that enters from the other end of the through-hole provided in the die D, and a shaft-shaped 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 the axial one-sided end face of the one-sided bearing portion Ba, and a one-sided inner punch Pa2 whose axial end face defines the axial one-sided face of the intermediate plate MP and whose outer peripheral surface defines the female engaging portion FE. The other-sided punch Pb further includes a the other-sided outer punch Pb1 whose axial end face defines the axial other-sided face of the intermediate plate MP and whose inner peripheral surface defines the male engaging portion ME, and a the other-sided inner punch Pb2 whose axial end face defines the axial other-sided end face of the other-sided bearing portion Bb. After the inside of the die D is filled with a powder material and the one-sided punch Pa and the other-sided punch Pb are combined as required, the one-sided punch Pa and the other-sided punch Pb are moved in a direction approaching each other inside the die D, so that the powder material filled inside the die D is compression-molded into the shape of the joint member P. At this time, due to the relatively short distance between the outer peripheral edge portion of the one-sided inner punch Pa2 and the inner peripheral edge portion of the other-sided outer punch Pb1 when viewed in the axial direction, there is a risk that the load concentrates on the corner portion between the outer peripheral surface of the other-sided bearing portion Bb and the axial other-sided face of the intermediate plate MP and the corner portion between the inner peripheral surface of the one-sided bearing portion Ba and the axial one-sided face of the intermediate plate MP, and the molding die M may be damaged. Further, even if the molding die M is not damaged, there is a risk that the above-mentioned corner portion may break when the molded product taken out from the molding die M is sintered.

[0008] The present invention has been made in view of the above facts, and its main technical problem is to provide a novel and improved angular position holding device including a joint member that can be integrally molded by powder metallurgy despite the female engaging portion and the male engaging portion being arranged at different positions on the same axis in the axial direction.

Means for Solving the Problems

[0009] As a result of intensive studies, the inventors of the present invention have found that the main technical problem can be solved by providing an annular thick portion at the corner between the outer peripheral surface of the other bearing portion having the male engaging portion and the axially other side surface of the intermediate plate to which the base ends of the female engaging portion and the male engaging portion are respectively connected in the joint member.

[0010] That is, according to the present invention, as an angular position holding device for solving the above main technical problem, it includes a joint member that connects an input-side device and an output-side device to each other, a braking torque applying means for applying a required braking torque to the joint member, and a supporting means for supporting the braking torque applying means. When a rotational torque is input from the input-side device, the joint member rotates with respect to the braking torque applying means against the required braking torque. When no rotational torque is input from the input-side device, in the angular position holding device where the joint member is held by the required braking torque, the joint member includes an intermediate plate disposed perpendicular to the axial direction, a cylindrical one-side bearing portion extending axially from one axial side surface of the intermediate plate, and another-side bearing portion extending axially from the axially other side surface of the intermediate plate. The one-side bearing portion and the another-side bearing portion have a common central axis. A female engaging portion is formed on the inner peripheral surface of the one-side bearing portion, and a male engaging portion is formed on the outer peripheral surface of the another-side bearing portion, and an annular thick portion is provided at the corner between the outer peripheral surface of the another-side bearing portion and the axially other side surface of the intermediate plate. An angular position holding device is provided, which is characterized by this.

[0011] Preferably, the outer peripheral surface of the thick-walled portion has a tapered shape that inclines radially inward toward the other side in the axial direction. Preferably, an auxiliary thick-walled portion is provided inside the female engaging portion on one axial side surface of the intermediate plate. Preferably, circular through holes that communicate with the inside of the one-sided bearing portion are formed in the intermediate plate and the other-side bearing portion. The intermediate plate has a disc shape, the one-sided bearing portion has a cylindrical shape extending axially on one side from the outer peripheral edge of the intermediate plate, and the braking torque applying means is preferably a coil spring disposed on the outer peripheral surface of the one-sided bearing portion and / or the outer peripheral surface of the intermediate plate. Preferably, the supporting means is a fixed housing, and the braking torque applying means is accommodated inside the housing. The male engaging portion and the female engaging portion are preferably both serrations or splines. In this case, it is preferable that the pitch circle diameters of the male engaging portion and the female engaging portion are about the same.

Effect of the Invention

[0012] In the angular position holding device configured according to the present invention, an annular thick-walled portion is provided at the corner between the outer peripheral surface of the other-side bearing portion having the male engaging portion and the other axial side surface of the intermediate plate in the joint member. Since the outer peripheral surface of such a thick-walled portion is defined by the inner peripheral edge portion of the axial front end surface of the other-side outer punch of the molding die, the outer peripheral edge portion of the axial front end surface of the one-sided inner punch and the inner peripheral edge portion of the axial front end surface of the other-side outer punch are separated from each other, and the load acting on the powder material existing therebetween is relaxed. Therefore, it is possible to prevent the load from concentrating on the above-mentioned corner portion during compression molding and the molding die from being damaged during molding, and also to prevent the above-mentioned corner portion from breaking when the molded product taken out from the molding die is sintered.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0014] Hereinafter, with reference to the accompanying drawings showing preferred embodiments of the angular position holding device configured according to the present invention, it will be described in more detail. In the following description, the terms "one axial side" and "the other axial side" are, unless otherwise specified, based on the state shown in the A-A cross section of FIG. 1. "One axial side" means the left side in the figure, and "the other axial side" means the right side in the figure.

[0015] Referring to FIG. 1, the angular position holding device, generally designated by reference numeral 2, includes 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 and a shaft S2 extending from the other, and integrally rotates the shaft S1 and the shaft S2. It is indicated by the rotation axis o of the coupling member 4. The coupling member 4 is integrally formed by powder metallurgy. The forming method will be described later. Referring to FIGS. 1 and 2 for explanation, the coupling member 4 includes an intermediate plate 10 arranged perpendicular to the axial direction (which is shown by a two-dot chain line for convenience in the cross-sectional view taken along line A-A in FIG. 2), a one-sided bearing portion 12 extending axially from one axial side surface of the intermediate plate 10, and the other-sided bearing portion 14 extending axially from the other axial side surface of the intermediate plate 10. The one-sided bearing portion 12 and the other-sided bearing portion 14 have a common central axis. Such a central axis is also common with the above rotation axis o. And, a female engaging portion 16 is formed on the inner peripheral surface of the one-sided bearing portion 12, and a male engaging portion 18 is formed on the outer peripheral surface of the other-sided bearing portion 14, respectively. In the illustrated embodiment, the intermediate plate 10 has a disc shape, and a circular through hole 19 that penetrates axially and communicates with the inside of the one-sided bearing portion 12 is formed in the intermediate plate 10 and the other-sided bearing portion 14. The through hole 19 is formed at the center of the intermediate plate 10. The one-sided bearing portion 12 has a cylindrical shape extending axially from the outer peripheral edge of the intermediate plate 10 to one axial side. An annular support ridge 20 extending in the circumferential direction is formed on the outer peripheral edge of the one axial side end surface of the one-sided bearing portion 12. Both the female engaging portion 16 and the male engaging portion 18 are serrations and have approximately the same pitch circle diameter. In the illustrated embodiment, the pitch circle diameter of the female engaging portion 16 is slightly larger than the pitch circle diameter of the male engaging portion 18, and the difference is 2.0%. It is preferable that the above difference is within 20%, and more preferably within 10%. The female engaging portion 16 and the male engaging portion 18 are respectively engaged with a male engaged portion S1a formed by serrations formed at the end of the shaft S1 and a female engaged portion S2a formed by serrations formed at the end of the shaft S2. Here, in the angular position holding device configured according to the present invention, it is important that an annular thick portion 21 is provided at the corner between the outer peripheral surface of the other-sided bearing portion 14 in the coupling member 4 and the other axial side surface of the intermediate plate 10. In the illustrated embodiment, the outer peripheral surface of the thick portion 21 has a tapered shape that inclines radially inward toward the other axial side.In the illustrated embodiment, an auxiliary wall thickness portion 22 is further formed inside the female engaging portion 16 on one axial side surface of the intermediate plate 10. The auxiliary wall thickness portion 22 has an annular shape surrounding the outer peripheral edge of the through hole 19 and is separated from the female engaging portion 16. The wall thickness portion 21 and the auxiliary wall thickness portion 22 will be described later together with the forming process of the joint member 4.

[0017] Referring to FIG. 1 for explanation, in the illustrated embodiment, the braking torque applying means 6 is a coil spring (hereinafter, the coil spring may also be indicated by the number 6), and includes a winding portion 23 in which a metal wire is spirally wound and a pair of hook portions 24a and 24b extending radially outward from the winding portion 23. The pair of hook portions 24a and 24b are constituted by both ends of the wire. Accordingly, the pair of hook portions 24a and 24b are respectively 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 subjected to 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 in a state where the inner diameter of the winding portion 23 is 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 joint member 4 and the braking torque applying means (coil spring 6) are accommodated 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 disposed perpendicular to the axial direction and a cylindrical outer peripheral wall 32 extending axially from the outer peripheral edge of the end plate to the other side in the axial direction. A circular through hole 34 penetrating axially is formed at the center of the end plate 30. Four arc-shaped holding recesses 36 having a required circumferential width are formed at intervals in the circumferential direction at the outer peripheral edge portion of one axial side surface of the end plate 30. An annular supported ridge 38 surrounding the outer peripheral edge of the through hole 34 is formed on the other axial side surface of the end plate 30. The supported ridge 38 is located inside the support ridge 20 of the joint member 4 to support it and also supports one axial side end surface of the joint member 4. Six arcuate holding grooves 40 extending linearly over the entire axial direction are formed on the outer peripheral surface of the outer peripheral wall 32 at equal angular intervals in the circumferential direction. The housing body 26 is fixed via the holding recesses 36 and the holding grooves 40. A pair of locking walls having a circular arc-shaped cross section extending axially to a required extent from the other axial side surface of the end plate 30 are provided on the inner peripheral surface of the outer peripheral wall 32 at intervals in the circumferential direction (each locking wall is denoted by 42a and 42b), and a pair of gaps 44a and 44b exist between the pair of locking walls 42a and 42b. The inner peripheral surfaces of the pair of locking walls 42a and 42b face the outer surface of the winding portion 23 of the coil spring 6, and a pair of hook portions 24a and 24b are commonly fitted into the gap 44b. Thus, the coil spring 6 is supported in a non-rotatable state with respect to the support means 8. An annular locking groove 46 extending in the circumferential direction is formed at the other axial end portion 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 penetrating axially is formed in the center of the shield plate 48, and one axial end portion of the other-side bearing portion 14 is inserted into the through-hole 50. An annular support wall 52 surrounding the outer peripheral edge of the through-hole 50 is formed on one axial side surface of the shield plate 48. A cylindrical mounting wall 54 extending axially from the outer peripheral edge is formed on the other axial side surface of the shield plate 48. An annular circumferential groove 56 opened toward the other axial side is formed in the mounting wall 54, and six ribs 57 are arranged in the circumferential groove 56 at equal angular intervals in the circumferential direction. An annular locking protrusion 58 extending in the circumferential direction is formed on the outer peripheral surface of the mounting wall 54, and the shield 28 is combined with the housing body 26 by locking the locking protrusion 58 in a locking groove 46 formed on the inner peripheral surface of the outer peripheral wall 32 of the housing body 26. Thus, one axial side surface of the shield plate 48 axially supports the other axial side surface of the intermediate plate 10 in 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 holding device 2 operates as follows. That is, since the shaft S1, the joint member 4, and the shaft S2 are integrated, when a rotational torque is input from the input-side device, the joint member 4 tries to rotate together with the coil spring 6. At this time, as described above, since the coil spring 6 is non-rotatable with respect to the support means 8 (housing), either one of the pair of hook portions 24a and 24b is pushed in a direction in which the coil spring 6 is loosened by one of the circumferential side surfaces of the pair of locking walls 42a and 42b within the gap 44b formed in the housing body 26, and the joint member 4 rotates with respect to the coil spring 6 against the required braking torque due to the tightening force of the coil spring 6. That is, the rotational torque from the input-side device is transmitted to the output-side device to drive it. On the other hand, when no rotational torque is input from the input-side device, the joint member 4 is held by the required braking torque by the coil spring 6. Thus, the angular position of the output-side device is held.

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

[0022] First, the molding die 100 for molding the joint member 4 will be described with reference to FIG. 5. The molding die 100 includes a die 102 penetrating in the axial direction, a one-sided punch 104 entering from one end into the through-hole provided in the die 102, the other-sided punch 106 entering from the other end thereof, and a shaft-shaped core 107 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 member 4, and the core 107 defines the through-hole 19 of the joint member 4. The one-sided punch 104 further includes a one-sided outer punch 108 whose axial end surface defines the axial one-sided end surface of the one-sided bearing portion 12, and a one-sided inner punch 110 whose axial end surface defines the axial one-sided surface of the intermediate plate 10 and whose outer peripheral surface defines the female engaging portion 16. The other-sided punch 106 further includes an other-sided outer punch 112 whose axial end surface defines the axial other-sided surface of the intermediate plate 10 and whose inner peripheral surface defines the male engaging portion 18, and an other-sided inner punch 114 whose axial end surface defines the axial other-sided end surface of the other-sided bearing portion 14. The axial tip surface of the one-sided outer punch 108 faces the axial tip surface of the other-sided outer punch 112, the axial tip surface of the one-sided inner punch 110 faces the axial tip surface of the other-sided inner punch 114, and both the one-sided outer punch 108 and the one-sided inner punch 110 as well as the other-sided outer punch 112 and the other-sided inner punch 114 are all movable forward and backward with respect to the die 102.

[0023] Next, a process of forming the joint member 4 using the molding die 100 will be described with reference to FIG. 4. First, as shown in FIG. 4(a), the inside of the die 102 is filled with a metallic powder material P. At this time, either one of the one-side punch 104 and the other-side punch 106 closes one end of the through-hole provided in the die 102. In the illustrated embodiment, first, the other-side punch 106 closes the other end of the through-hole, and after the powder material P is introduced into the inside of the die 102, as shown in FIG. 4(b), the one-side punch 104 closes one end of the through-hole. Next, from the state shown in FIG. 4(b), the one-side outer punch 108 and the one-side inner punch 110 constituting the one-side punch 104 and the other-side outer punch 112 and the other-side inner punch 114 constituting the other-side punch 106 move as required without applying excessive pressure to the powder material P, and the space filled with the powder material P is shaped into a shape similar to the joint member 4. Such a process is called transfer and is well-known to those skilled in the art. FIG. 4(c) shows the state after the transfer. Then, after the transfer is performed, as shown in FIG. 4(d), the one-side punch 104 and the other-side punch 106 are moved in a direction approaching each other inside the die 102, so that the powder material P filled inside the die 102 is compression-molded into the shape of the joint member 4. Thereafter, as shown in FIG. 4(e), the one-side punch 104 and the other-side punch 106 move relative to the die 102, and the compression-molded joint member molded body 4' is taken out. Then, the taken-out joint member molded body 4' is sintered in an appropriate furnace, whereby the joint member 4 is formed.

[0024] Referring to FIG. 5, in the angular position holding device configured according to the present invention, an annular thick portion 21 is provided at the corner of the outer peripheral surface of the other bearing portion 14 having the male engaging portion 18 in the joint member 4 (4') and the other axial surface of the intermediate plate 10. Since the outer peripheral surface of such a thick portion 21 is defined by the inner peripheral edge portion of the axial front end surface of the other outer punch 112 of the molding die 100, the outer peripheral edge portion of the axial front end surface of the one-sided inner punch 110 and the inner peripheral edge portion of the axial front end surface of the other outer punch 112 are separated, and the load acting on the powder material P existing therebetween is relaxed. Therefore, it is possible to prevent the load from concentrating on the above-mentioned corner portion during compression molding and the molding die 100 from being damaged, and also to prevent the above-mentioned corner portion from breaking when the joint member molded body 4' (molded product) taken out from the molding die 100 is sintered. Thus, an angular position holding device including a joint member 4 integrally moldable by powder metallurgy is obtained, although the female engaging portion 16 and the male engaging portion 18 are arranged at different positions in the coaxial axial direction. In the illustrated embodiment, since the outer peripheral surface of the thick portion 21 has a tapered shape that inclines radially inward toward the other axial side, the other outer punch 112 is easily demolded. In the illustrated embodiment, further, an auxiliary thick portion 22 is provided inside the female engaging portion 16 on one axial side surface of the intermediate plate 10. As a result, the volume in the vicinity of the above-mentioned corner portion increases, and the load acting on the above-mentioned corner portion during compression molding is further relaxed. The auxiliary thick portion 22 also functions as a positioning support for the other axial end surface of the shaft S1. At this time, since the outer peripheral edge portion of the other axial end surface of the shaft S1 is usually chamfered, the auxiliary thick portion 22 is preferably arranged relatively radially inwardly separated from the female engaging portion 16.

[0025] As described above, the angular position holding device configured according to the present invention has been described in detail with reference to the attached drawings. However, the present invention is not limited to the above-described embodiments, and appropriate modifications and changes can be made without departing from the scope of the present invention. For example, in the illustrated embodiment, both the female engaging portion 16 and the male engaging portion 18 are serrations, but they may be splines. Further, since the braking torque applying means only needs to apply the required braking torque to the joint member, it is not limited to a coil spring and can be replaced by various means such as a leaf spring or a so-called ring spring. Furthermore, since the supporting means only needs to support the braking torque applying means, it is not necessarily limited to being a housing. When the braking torque applying means is a coil spring, the supporting means may be an appropriate engaging portion that supports, for example, a pair of hook portions.

Explanation of Reference Numerals

[0026] 2: Angular position holding device 4: Joint member 6: Braking torque applying means (coil spring) 8: Supporting means (housing) 10: Intermediate plate 12: One-sided bearing portion 14: The other-sided bearing portion 16: Female engaging portion 18: Male engaging portion 21: Thick portion 22: Auxiliary thick portion

Claims

1. An angular position holding device comprising a joint member that interconnects an input-side device and an output-side device, a braking torque applying means that applies a required braking torque to the joint member, and a support means that supports the braking torque applying means. When a rotational torque is input from the input-side device, the joint member rotates relative to the braking torque applying means against the required braking torque. When no rotational torque is input from the input-side device, the joint member is held at an angular position by the required braking torque, wherein the joint member includes an intermediate plate disposed perpendicular to the axial direction, a cylindrical one-side bearing portion extending axially from one axial-side surface of the intermediate plate, and another-side bearing portion extending axially from the other axial-side surface of the intermediate plate. The one-side bearing portion and the another-side bearing portion have a common central axis. An internal engaging portion is formed on the inner peripheral surface of the one-side bearing portion, and an external engaging portion is formed on the outer peripheral surface of the another-side bearing portion, respectively, an annular thick portion is provided at a corner between the outer peripheral surface of the another-side bearing portion and the other axial-side surface of the intermediate plate. The angular position holding device is characterized by this.

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

3. The angular position holding device according to claim 1, wherein an auxiliary thick portion is provided inside the internal engaging portion on one axial-side surface of the intermediate plate.

4. The angular position holding device according to claim 1, wherein circular through-holes that communicate with the inside of the one-side bearing portion are formed in the intermediate plate and the another-side bearing portion.

5. The intermediate plate has a disc shape, the one-side bearing portion has a cylindrical shape extending axially from an outer peripheral edge of the intermediate plate, and the braking torque applying means is a coil spring disposed on an outer peripheral surface of the one-side bearing portion and / or an outer peripheral surface of the intermediate plate. The angular position holding device is characterized by this.

6. The support means is a fixed housing, and the braking torque applying means is housed inside the housing. The angular position holding device is characterized by this.

7. The angular position holding device according to claim 1, wherein both the external engaging portion and the internal engaging portion are serrations or splines.

8. The angular position holding device according to claim 7, wherein pitch circle diameters of the external engaging portion and the internal engaging portion are approximately the same.

Images