Angle position maintaining device

Abstract

The present invention provides a novel angle position maintaining device having a joint member (4) that can be integrally formed by powder metallurgy, even though the female fitting part (16) and the male fitting part (18) are positioned at different axial positions on the same axis. In the joint member (4), an annular thick section (21) is installed on the outer surface of the other side bearing part (14) having the male fitting part (18) and on the corner of the other side of the axial direction of the intermediate plate (10).

Description

Technology Field

[0001] The present invention relates to an angle position maintaining device comprising a joint member connecting 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 support means for supporting the braking torque applying means. Background Technology

[0002] Patent Document 1 below discloses an angle position maintaining device that is mounted on a shaft that transmits rotational torque from an input device, such as an electric motor, to an output device, such as a hatchback of a vehicle, and allows the shaft to rotate in resistance to the required braking torque when rotational torque is input from the input device, while maintaining the shaft by the required braking torque when rotational torque is not input from the input device, that is, maintaining the angle position of the output device even when the driving of the input device is stopped. Prior art literature

[0003] Japanese Patent Publication No. 6815567 The problem to be solved

[0004] In the angle position maintaining device disclosed in the above patent document 1, the shaft extending from the input device was directly connected to the output device; however, depending on the configuration of the input device and the output device, both the input device and the output device may be equipped with a shaft that transmits rotation. In this case, both shafts are connected by an angle position maintaining device. That is, the angle position maintaining device also functions as a joint, and the shaft extending from the input device and the shaft extending from the output device are connected through the angle position maintaining device. Here, if both the shaft extending from the input device and the shaft extending from the output device are equipped with a male-type engaging part, the joint member is equipped with a female-type engaging part that engages with the male-type engaging part, and if both shafts are equipped with a female-type engaging part, the joint member is equipped with a male-type engaging part that engages with the female-type engaging part. Meanwhile, in the case where a shaft extending from an input device and a shaft extending from an output device each have a male engaging part and a female engaging part, the joint member has a female engaging part and a male engaging part that engage with said male engaging part and female engaging part. The female engaging part and the male engaging part are arranged coaxially.

[0005] In addition, the braking torque imparting means provided by the angle position maintaining device disclosed in the above patent document 1 is a coil spring. The coil spring is mounted on the outer circumference of an inner ring through which the shaft passes. The inner ring rotates in resistance to the braking torque resulting from the clamping force of the coil spring; that is, the inner ring slides relative to the coil spring. For this reason, the inner ring needs to possess considerable strength including wear resistance and is manufactured by powder metallurgy. The braking torque imparting means is not limited to a coil spring and may be a leaf spring or a so-called ring spring, etc.

[0006] However, when the joint member described above, that is, the joint member in which the female and male parts are respectively arranged coaxially, is used as the inner ring of the angle position maintaining device disclosed in Patent Document 1, since it is necessary to install a cylindrical part for mounting a coil spring in the joint member, the female and male parts cannot be arranged at the same position in the axial direction coaxially, and thus need to be arranged at different positions in the axial direction coaxially. The same applies when the braking torque imparting means is other than a coil spring. Accordingly, such a joint member comprises an intermediate plate arranged perpendicular to the axial direction, a cylindrical one-sided bearing part extending axially from one axial side of the intermediate plate, and a other-sided bearing part extending axially from the other axial side of the intermediate plate, and the one-sided bearing part and the other-sided bearing part have a common central axis, and the female part is formed on the inner circumference of the one-sided bearing part and the male part is formed on the outer circumference of the other-sided bearing part.

[0007] In order to manufacture such joint members integrally by powder metallurgy, it is common to use a forming die (M) as shown in FIG. 6. Referring to FIG. 6, the forming die (M) comprises a die (D) that penetrates in the axial direction and whose inner surface defines the outer surface of the joint member (P), a one-sided punch (Pa) that enters from one side of the through hole provided by the die (D), a other-sided punch (Pb) that enters from the other end of the through hole provided by the die (D), and an axial core (C) that is inserted and passes through the one-sided punch (Pa) and the other-sided punch (Pb). One-sided punch (Pa) further comprises a one-sided outer punch (Pa1) whose axial end surface defines the axial end surface of the one-sided bearing part (Ba), and a one-sided inner punch (Pa2) whose axial end surface defines the axial end surface of the intermediate plate (MP) and whose outer surface defines the female fitting part (FE). The other-sided punch (Pb) additionally comprises a other-sided outer punch (Pb1) whose axial end surface defines the axial end surface of the intermediate plate (MP) and whose inner surface defines the male fitting part (ME), and a other-sided inner punch (Pb2) whose axial end surface defines the axial end surface of the other-sided bearing part (Bb). After the powder material is filled into the inner side of the die (D) and the one-sided punch (Pa) and the other-sided punch (Pb) are combined as needed, the one-sided punch (Pa) and the other-sided punch (Pb) are moved in a direction approaching each other within the inner side of the die (D), thereby compression molding the powder material filled into the inner side of the die (D) into the shape of a joint member (P). At this time, due to the relatively short distance between the outer edge of the one-sided inner punch (Pa2) and the inner edge of the other-sided outer punch (Pb1) when viewed in the axial direction, the load is concentrated on the outer surface of the other-sided bearing part (Bb) and the corner of the axial side of the intermediate plate (MP), and the inner surface of the one-sided bearing part (Ba) and the corner of the axial side of the intermediate plate (MP), so there is a risk that this corner may break or the molding die (M) may be damaged.In addition, even if the corner portion does not break or the molding die (M) is not damaged during compression molding, there is a risk that the corner portion may break when the molded product removed from the molding die (M) is sintered.

[0008] The present invention has been made in consideration of the above facts, and its main technical problem is to provide a novel and improved angle position maintaining device having a joint member that can be integrally molded by powder metallurgy, even though the female fitting and the male fitting are positioned at different axial positions on the same axis. means of solving the problem

[0009] As a result of careful examination, the inventors have discovered that the above-mentioned main technical problem can be solved by installing an annular thick section at the corner of the axial side of the other side of the bearing part having a male fitting part in the joint member and the outer surface of the other side bearing part having a male fitting part.

[0010] That is, according to the present invention, an angle position maintaining device solving the above main technical problem comprises a joint member connecting 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 support means for supporting the braking torque applying means, wherein when a rotational torque is input from the input-side device, the joint member rotates relative to the braking torque applying means in resistance to the required braking torque, and when a rotational torque is not input from the input-side device, the joint member is maintained by the required braking torque.

[0011] The joint member comprises an intermediate plate arranged perpendicular to the axial direction, a tubular unilateral bearing portion extending axially from one axial side of the intermediate plate, and a unilateral bearing portion extending axially from the other axial side of the intermediate plate, wherein the unilateral bearing portion and the unilateral bearing portion have a common central axis, and a female-shaped interlocking portion is formed on the inner surface of the unilateral bearing portion, and a male-shaped interlocking portion is formed on the outer surface of the unilateral bearing portion.

[0012] An angle position maintaining device is provided, characterized in that an annular thick section is installed on the outer surface of the other bearing part and on the corner portion of the other side in the axial direction of the intermediate plate.

[0013] Preferably, the outer surface of the thick section has a tapered shape that slopes inward in the radial direction toward the other axial side. Suitablely, an auxiliary thick section is installed on the inner side of the female engagement section on one axial side of the intermediate plate. It is preferable that a circular through hole is formed in the intermediate plate and the other bearing section to communicate with the inner side of the one-sided bearing section. The intermediate plate is in the shape of a disc, and the one-sided bearing section is in the shape of a cylinder extending axially in one direction from the outer edge of the intermediate plate; and the braking torque applying means is preferably a coil spring installed on the outer surface of the one-sided bearing section and / or the outer surface of the intermediate plate. Preferably, the support means is a fixed housing, and the braking torque applying means is received inside the housing. It is preferable that both the male engagement section and the female engagement section have serrations or splines. In this case, it is preferable that the pitch circle diameters of the male engagement section and the female engagement section are approximately the same. Effects of the invention

[0014] In an angle position maintaining device configured according to the present invention, an annular thick section is installed at the corner portion of the axial side of the intermediate plate and the outer surface of the other bearing portion having a male fitting portion in the joint member. Since the outer surface of this thick section is defined by the inner circumferential edge portion of the axial front surface of the other outer punch of the molding die, the outer circumferential edge portion of the axial front surface of the one inner punch and the inner circumferential edge portion of the axial front surface of the other outer punch are spaced apart, thereby mitigating the load acting on the powder material present therebetween. Consequently, during compression molding, the load is prevented from concentrating on the corner portion, thereby preventing the corner portion from breaking or the molding die from being damaged, and also prevents the corner portion from breaking when the molded product removed from the molding die is sintered. Brief explanation of the drawing

[0015] FIG. 1 is a drawing showing a suitable embodiment of an angle position maintaining device configured according to the present invention. Figure 2 is a drawing showing the joint member of the angle position maintaining device shown in Figure 1 as a single unit. Figure 3 is a drawing showing the housing of the angle position maintaining device shown in Figure 1 as a single unit. Figure 4 is a drawing illustrating the process of forming the joint member shown in Figure 2. Figure 5 is an enlarged view of a portion of the drawing explaining the compression process in Figure 4. FIG. 6 is a drawing showing a molding die for forming one embodiment of a joint member. Specific details for implementing the invention

[0016] Hereinafter, a suitable embodiment of an angle position maintaining device configured according to the present invention will be described in more detail with reference to the attached drawings. In addition, in the following description, the terms "axial side" and "axial other side" shall be defined as follows, based on the state shown in the cross-section AA of FIG. 1, where "axial side" is the left side and "axial other side" is the right side.

[0017] Referring to FIG. 1, the angle position maintaining device, denoted as number 2, comprises a joint member (4), a braking torque applying means (6), and a support means (8).

[0018] The joint 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 side, thereby rotating the shaft (S1) and the shaft (S2) together. This is indicated by the rotation axis (o) of the joint member (4). The joint member (4) is integrally formed by powder metallurgy. The forming method will be described later. Referring to FIG. 2 together with FIG. 1, the joint member (4) is provided with an intermediate plate (10) arranged perpendicular to the axial direction (this is indicated by a dotted line for convenience in the cross-sectional view of FIG. 2 AA line), a unilateral bearing part (12) extending axially from one axial side of the intermediate plate (10), and a unilateral bearing part (14) extending axially from the other axial side of the intermediate plate (10), and the unilateral bearing part (12) and the unilateral bearing part (14) have a common central axis. This central axis is also common with the rotation axis (o). Additionally, a female-shaped engagement part (16) is formed on the inner surface of the one-sided bearing part (12), and a male-shaped engagement part (18) is formed on the outer surface of the other-sided bearing part (14). In the illustrated embodiment, the intermediate plate (10) is in the shape of a disc, and a circular through hole (19) is formed in the intermediate plate (10) and the other-sided bearing part (14) to penetrate in the axial direction and communicate with the inside of the one-sided bearing part (12). The through hole (19) is formed in the center of the intermediate plate (10). The one-sided bearing part (12) is cylindrical in shape, extending axially from the outer edge of the intermediate plate (10). An annular support projection (20) extending in the circumferential direction is formed on the outer edge of the axial cross-section of the one-sided bearing part (12). The female fitting part (16) and the male fitting part (18) are both serrated, and the pitch circle diameters are about the same. In the illustrated embodiment, the pitch circle diameter of the female fitting part (16) is slightly larger than the pitch circle diameter of the male fitting part (18), and the difference is 2.0%.The above difference is preferably within 20%, and more preferably within 10%. The female-type engaging part (16) and the male-type engaging part (18) are respectively engaged with the male-type engaging part (S1a) formed by serrations formed at the end of the shaft (S1) and the female-type engaging part (S2a) formed by serrations formed at the end of the shaft (S2). Here, in the angle position maintaining device configured according to the present invention, it is important that an annular thick section (21) is installed on the outer surface of the other side bearing part (14) of the joint member (4) and the corner of the axial other side of the intermediate plate (10). In the illustrated embodiment, the outer surface of the thick section (21) is tapered in a radial inward shape toward the axial other side. In the illustrated embodiment, an auxiliary thick section (22) is also formed on the inner side of the female-shaped fitting section (16) on one side in the axial direction of the intermediate plate (10). The auxiliary thick section (22) is an annular shape surrounding the outer edge of the through hole (19) and is spaced apart from the female-shaped fitting section (16). The thick section (21) and the auxiliary thick section (22) will be described later together with the molding process of the joint member (4).

[0019] Referring to FIG. 1, in the illustrated embodiment, the braking torque applying means (6) is a coil spring (hereafter, the coil spring may be denoted by number 6), and is provided with a coil portion (23) in which a metal wire is wound in a spiral shape, and a pair of hook portions (24a and 24b) in which the wire extends outward in the radial direction from the coil portion (23). The pair of hook portions (24a and 24b) are formed by both ends of the wire. Accordingly, the pair of hook portions (24a and 24b) are each installed at both ends in the axial direction of the coil 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 coil portion (23) is smaller than the outer diameter of the one-sided bearing portion (12) of the joint member (4), and the coil spring (6) is mounted in close contact with the outer surface of the one-sided bearing portion (12) with the inner diameter of the coil portion (23) expanded. If necessary, the coil spring (6) may be mounted on the outer surface of the one-sided bearing portion (12) and / or the outer surface of the intermediate plate (10).

[0020] In the illustrated embodiment, the support means (8) is a fixed housing, and the joint member (4) and the braking torque imparting means (coil spring (6)) are accommodated inside the housing. Referring to FIGS. 1 and FIGS. 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 wall (32) extending axially from the outer edge of the end plate. A circular through hole (34) penetrating axially is formed in the center of the end plate (30). Four arc-shaped retaining concave portions (36) having a required circumferential width are formed at intervals in the circumferential direction on the outer edge portion of the axial side of the end plate (30). On the axial side of the single plate (30), a ring-shaped supporting projection (38) is formed to surround the outer edge of the through hole (34). The supporting projection (38) is located inside the supporting projection (20) of the joint member (4) to support it and also supports the axial side cross section of the joint member (4). On the outer surface of the outer wall (32), six arc-shaped retaining grooves (40) are formed at equal intervals in the circumferential direction, extending in a straight line shape across the entire axial direction. The housing body (26) is fixed through the retaining grooves (36) and the retaining grooves (40). On the inner surface of the outer wall (32), a pair of cross-sectional arc-shaped locking walls are installed at intervals in the circumferential direction, extending axially from the other side of the plate (30) in the axial direction (each locking wall is denoted as 42a and 42b), and a pair of gaps (44a and 44b) exist between the pair of locking walls (42a and 42b). The inner surface of the pair of locking walls (42a and 42b) faces the outer surface of the coiling portion (23) of the coil spring (6), and a pair of hook portions (24a and 24b) are fitted in common into the gap (44b).In this way, the coil spring (6) is supported with respect to the support means (8) in a state where it cannot rotate. An annular locking groove (46) extending in the circumferential direction is formed at the other axial end of the inner circumferential surface of the outer wall (32).

[0021] The shield (28) includes a circular shield plate (48) positioned perpendicular to the axial direction. A circular through hole (50) is formed in the center of the shield plate (48) and penetrates in the axial direction, and the axial end of the other bearing part (14) is inserted and passes through the through hole (50). An annular support wall (52) is formed on the axial side of the shield plate (48) to surround the outer edge of the through hole (50). A cylindrical mounting wall (54) is formed on the axial side of the shield plate (48) to extend axially from the outer edge. An annular circumferential groove (56) is formed in the mounting wall (54) and is open toward the axial side, and six ribs (57) are arranged and installed in the circumferential groove (56) at equal angular intervals in the circumferential direction. On the outer surface of the mounting wall (54), a ring-shaped fixing projection (58) extending in the circumferential direction is formed, and the fixing projection (58) is fixed by being caught in a fixing groove (46) formed on the inner surface of the outer wall (32) of the housing body (26), thereby the shield (28) is assembled to the housing body (26). In this way, the axial side of the shield plate (48) supports the other axial side of the intermediate plate (10) in the joint member (4) in the axial direction, and the inner surface of the support wall (52) supports the outer surface of the intermediate plate (10) in the radial direction.

[0022] The angle position maintaining device (2) operates as follows. That is, since the shaft (S1), the joint member (4), and the shaft (S2) are integral, when rotational torque is input from the input side device, the joint member (4) attempts to rotate together with the coil spring (6). At this time, as described above, since the coil spring (6) is unable to rotate relative to the support means (8) (housing), either of the pair of hook parts (24a and 24b) is pushed in a direction in which the coil spring (6) becomes relatively loose by the circumferential side of either of the pair of locking fixed walls (42a and 42b) within the gap (44b) formed in the housing body (26), and the joint member (4) rotates relative to the coil spring (6) by resisting the required braking torque caused by 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 and drives it. Meanwhile, when no rotational torque is input from the input device, the joint member (4) is maintained by the required braking torque of the coil spring (6). In this way, the angular position of the output device is maintained.

[0023] Next, the process of integrally forming the joint member (4) described above by powder metallurgy will be explained with reference to FIGS. 4 and FIG. 5. FIG. 4 shows an overall diagram of the forming process, and FIG. 5 shows a diagram of the compression process shown in FIG. 4.

[0024] First, a molding die (100) for forming a joint member (4) will be described with reference to FIG. 5. The molding die (100) comprises a die (102) that penetrates in the axial direction, a one-sided punch (104) that enters from one end of the through hole provided by the die (102), a other-sided punch (106) that enters from the same other end, and an axial core (107) that is inserted and passes through the inside of the one-sided punch (104) and the other-sided punch (106). The inner surface of the die (102) defines the outer 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) additionally comprises a one-sided outer punch (108) in which the axial cross-section defines the axial cross-section of the one-sided bearing part (12), and a one-sided inner punch (110) in which the axial cross-section defines the axial cross-section of the intermediate plate (10) and the outer surface defines the female fitting part (16). The other-sided punch (106) additionally comprises a other-sided outer punch (112) in which the axial cross-section defines the axial cross-section of the intermediate plate (10) and the inner surface defines the male fitting part (18), and a other-sided inner punch (114) in which the axial cross-section defines the axial cross-section of the other-sided bearing part (14). The axial front surface of the unilateral outer punch (108) faces the axial front surface of the other unilateral outer punch (112), and the axial front surface of the unilateral inner punch (110) faces the axial front surface of the other unilateral inner punch (114), and the unilateral outer punch (108), the unilateral inner punch (110), the other unilateral outer punch (112), and the other unilateral inner punch (114) are all capable of moving back and forth with respect to the die (102).

[0025] Next, referring to FIG. 4, a process for forming 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 into the inside of the die (102). At this time, either one of the one-sided punch (104) and the other-sided punch (106) blocks one end of the through hole provided by the die (102). In the illustrated embodiment, the other-sided punch (106) first blocks the other end of the through hole, and after the powder material (P) is introduced into the inside of the die (102), the one-sided punch (104) blocks one end of the through hole as shown in FIG. 4(b). Next, from the state shown in FIG. 4(b), the one-sided outer punch (108) and one-sided inner punch (110) constituting the one-sided punch (104), and the other-sided outer punch (112) and other-sided inner punch (114) constituting the other-sided punch (106) are each moved as needed without applying excessive pressure to the powder material (P), so as to form a shape similar to the joint member (4) that forms the space filled with the powder material (P). This process is called a transfer and is a well-known technique 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-sided punch (104) and the other-sided punch (106) are moved in a direction that approaches each other inside the die (102), thereby compression molding the powder material (P) filled inside the die (102) into the shape of the joint member (4). After that, as shown in FIG. 4(e), one side punch (104) and the other side punch (106) are moved relative to the die (102) to take out a compression-molded joint member molded body (4'). Then, the joint member (4) is formed by sintering the taken-out joint member molded body (4') in a suitable furnace.

[0026] Referring to FIG. 5, in the angle position maintaining device configured according to the present invention, an annular thick section (21) is installed on the outer surface of the other side bearing section (14) having a male fitting section (18) in the joint member (4)(4') and on the corner of the axial other side of the intermediate plate (10). Since the outer surface of this thick section (21) is defined by the inner circumferential edge of the axial front surface of the other side outer punch (112) of the molding die (100), the outer circumferential edge of the axial front surface of the one side inner punch (110) and the inner circumferential edge of the axial front surface of the other side outer punch (112) are separated, and the load acting on the powder material (P) present therebetween is relieved. Therefore, during compression molding, the load is concentrated on the corner portion, preventing the corner portion from breaking or the molding die (100) from being damaged, and the corner portion is prevented from breaking when the joint member molded body (4') (molded product) removed from the molding die (100) is sintered. In this way, an angle position maintaining device is obtained that has a joint member (4) that can be integrally molded by powder metallurgy, even though the female fitting portion (16) and the male fitting portion (18) are positioned at different axial positions on the same axis. In the illustrated embodiment, since the outer surface of the thick portion (21) has a tapered shape that slopes inward in the radial direction toward the other axial side, the other outer punch (112) is well detached. In the illustrated embodiment, an auxiliary thick section (22) is installed on the inner side of the female fitting section (16) on one axial side of the intermediate plate (10), and as a result, the volume near the corner section is increased, so the load acting on the corner section during compression molding is further relieved. The auxiliary thick section (22) supports the other axial end of the shaft (S1) and also functions as a positioning element.At this time, since the outer edge of the cross-section on the other side in the axial direction of the shaft (S1) is typically chamfered, it is preferable that the auxiliary thick section (22) be spaced apart from the female fitting section (16) and positioned relatively inward in the radial direction.

[0027] Although the angle position maintaining device configured according to the present invention has been described in detail above with reference to the attached drawings, the present invention is not limited to the embodiments described above, and appropriate modifications or changes are possible within the scope of the present invention without departing from it. For example, in the illustrated embodiment, the female engaging part (16) and the male engaging part (18) were both serrations, but they may also be splines. Furthermore, 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 with various means such as a leaf spring or a so-called ring spring. Also, since the support 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 support means may be, for example, a suitable engaging part that supports a pair of hook parts. Explanation of the symbols

[0028] 2: Angle position holding device 4: Joint member 6: Means of applying braking torque (coil spring) 8: Support means (housing) 10: Intermediate Edition 12: Unilateral bearing section 14: Other side bearing section 16: Female joint 18: Tree shape fitting part 21: Thick section 22: Auxiliary thick section

Claims

Claim 1 A joint member connecting an input device and an output device, a braking torque applying means for applying a required braking torque to the joint member, and a support means for supporting the braking torque applying means. When rotational torque is input from the input device, the joint member rotates relative to the braking torque applying means in resistance to the required braking torque. When rotational torque is not input from the input device, the joint member is an angle position maintaining device maintained by the required braking torque. The joint member comprises an intermediate plate arranged perpendicular to the axial direction, a tubular one-sided bearing portion extending axially from one axial side of the intermediate plate, and a other-sided bearing portion extending axially from the other axial side of the intermediate plate. The one-sided bearing portion and the other-sided bearing portion have a common central axis. A female-shaped engagement portion is formed on the inner surface of the one-sided bearing portion, and a male-shaped engagement portion is formed on the outer surface of the other-sided bearing portion. An annular thick portion is installed at the corner of the outer surface of the other-sided bearing portion and the other axial side of the intermediate plate. Angle position maintaining device featuring Claim 2 An angle position maintaining device according to claim 1, wherein the outer surface of the thick portion is tapered in a diameter direction inward toward the other side in the axial direction. Claim 3 An angle position maintaining device according to claim 1, wherein an auxiliary thick section is installed on the inner side of the female fitting section on one axial side of the intermediate plate. Claim 4 An angle position maintaining device according to claim 1, wherein a circular through hole is formed in the intermediate plate and the other side bearing part that communicates to the inside of the one side bearing part. Claim 5 An angle position maintaining device according to claim 1, wherein the intermediate plate is in the shape of a disc, the unilateral bearing portion is in the shape of a cylinder extending axially in one direction from the outer edge of the intermediate plate, and the braking torque applying means is a coil spring installed by being disposed on the outer surface of the unilateral bearing portion and / or the outer surface of the intermediate plate. Claim 6 An angle position maintaining device according to claim 1, wherein the support means is a fixed housing, and the braking torque applying means is received inside the housing. Claim 7 An angle position maintaining device according to claim 1, wherein the male fitting part and the female fitting part are both serrations or splines. Claim 8 An angle position maintaining device according to claim 7, wherein the pitch circle diameters of the male fitting part and the female fitting part are approximately the same.

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