Torque limiter

Abstract

To provide a novel torque limiter in which an inner member (6a to 6d) does not shake in the axial direction in an inner space (16a to 16d) having a side in the axial direction closed by a shield member (10a to 10d) even if the length of the inner space (16a to 16d) in the axial direction is longer than the length of the inner member (6a to 6d) in the axial direction.SOLUTION: The inner member (6a to 6d) or a braking member (8a to 8d) in close contact with the inner member is biased in the axial direction against an outer member (4a to 4d) and the shield member (10a to 10d).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a torque limiter.

Background Art

[0002] Patent Document 1 below discloses a torque limiter including an outer member having an inner space that is closed on one axial side and open on the other side, an inner member and a braking member (coil spring) housed in the inner space, and a shield member that is combined with the outer member after the inner member and the braking member are housed in the inner space to close the other side of the inner space. The outer member and the inner member are relatively rotatable, and the braking member is disposed between the outer member and the inner member to apply a required braking torque to the relative rotation. Since the other side of the inner space is closed by the shield member after the inner member and the braking member are housed in the inner space, the axial length of the inner space closed by the shield member on the other side is longer than the axial length of the inner member.

[0003] In the torque limiter disclosed in Patent Document 1, both the outer member and the inner member are rotatable, but either one of them may be fixed. When either one of them is fixed, the torque limiter can be used, for example, as an angular position holding device when rotating and driving a hatchback of a vehicle by a driving means such as an electric motor. In such an angular position holding device, an electromagnetic brake is usually used, but since the electromagnetic brake has a complicated configuration and is expensive, it is desired to use a mechanical torque limiter having a simple configuration and low cost. In this case, the outer member is fixed to the vehicle as a housing, and the inner member is connected to a shaft connecting the electric motor and the hatchback. Further, as shown in Japanese Patent No. 7035254, which was previously filed by the applicant of the present application and has already been patented, the inner member may be used as a joint member connecting a shaft extending from the electric motor and a shaft extending from the hatchback.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the torque limiter disclosed in the above Patent Document 1, since the axial length of the inner space closed by the shield member on the other side is longer than the axial length of the inner member, the inner member has axial play in the inner space, and there is a risk of generating an unfavorable abnormal noise during operation due to such play.

[0006] The present invention has been made in view of the above facts, and its main technical problem is to provide a novel and improved torque limiter in which the inner member does not have axial play in the inner space even when the axial length of the inner space closed by the shield member on the other side is longer than the axial length of the inner member.

Means for Solving the Problems

[0007] As a result of intensive studies, the inventors of the present invention have found that the main technical problem can be solved by axially biasing the inner member or the braking member in close contact therewith with respect to the outer member and the shield member. elastically That is, according to the first aspect of the present invention, as a torque limiter for solving the above main technical problem, an outer member having an inner space that is closed on one axial side but open on the other side, an inner member and a braking member accommodated in the inner space, and a shield member that is combined with the outer member after the inner member and the braking member are accommodated in the inner space to close the other side of the inner space,

[0008] the axial length of the inner space closed by the shield member on the other side is longer than the axial length of the inner member, ​In the torque limiter in which the outer member and the inner member are relatively rotatable, and the braking member is disposed between the outer member and the inner member to apply a required braking torque to the relative rotation, the inner member is axially biased against the outer member and the shield member by a biasing means. elastically There is provided a torque limiter, characterized in that.

[0009] In this case, it is preferable that the biasing means is a wave washer housed in the inner space.

[0010] According to a second aspect of the present invention, as a torque limiter for solving the above main technical problem, an outer member having an inner space that is closed on one axial side but open on the other side, an inner member and a braking member housed in the inner space, and a shield member that is combined with the outer member after the inner member and the braking member are housed in the inner space to close the other side of the inner space. The axial length of the inner space closed by the shield member is longer than the axial length of the inner member. In the torque limiter in which the outer member and the inner member are relatively rotatable, and the braking member is disposed between the outer member and the inner member to apply a required braking torque to the relative rotation, The braking member is in close contact with the inner member and is axially biased against the outer member and the shield member. elastically There is provided a torque limiter, characterized in that.

[0011] In this case, the braking member is a compression coil spring that is compressed from both axial sides by the outer member and the shield member, and includes a winding portion around which a wire is wound and a hook portion that extends in a direction in which the wire is separated from the winding portion. The outer peripheral surface of the inner member has a cylindrical shape, and the winding portion of the compression coil spring is mounted on the outer peripheral surface. The diameter of the outer peripheral surface is preferably larger than the inner diameter of the winding portion when the compression coil spring is in a free state. Further, the braking member is a coil spring that includes a winding portion around which a wire is wound and a hook portion that extends in a direction in which the wire is separated from the winding portion. The outer peripheral surface of the inner member has a cylindrical shape, and the winding portion of the coil spring is mounted on the outer peripheral surface. The diameter of the outer peripheral surface is larger than the inner diameter of the winding portion when the coil spring is in a free state, and urging means for axially urging the coil spring may be integrally formed on the shield member and / or the outer member. Furthermore, the braking member is a coil spring that includes a winding portion around which a wire is wound and a hook portion that extends in a direction in which the wire is separated from the winding portion. The outer peripheral surface of the inner member has a cylindrical shape, and the winding portion of the coil spring is mounted on the outer peripheral surface. The diameter of the outer peripheral surface is larger than the inner diameter of the winding portion when the coil spring is in a free state, and urging means for axially urging the coil spring may also be accommodated in the inner space.

[0012] In both the first aspect and the second aspect of the present invention, the outer member is a fixed housing, and the inner member is connected to an external device and can be used as an angular position holding device.

Advantages of the Invention

[0013] In the torque limiter configured according to the first aspect of the present invention, the inner member is axially elasticallyBy being biased, in the inner space where the other axial side is closed by the shield member, both axial ends of the inner member are supported by either the biasing means and the axial side surface of the outer member or the axial side surface of the shield member, or simultaneously by the biasing means arranged on both axial sides. Therefore, the generation of abnormal noise due to axial play is prevented.

[0014] In the torque limiter configured according to the second aspect of the present invention, the braking member is axially biased with respect to the outer member and the shield member. elastically By being biased, in the inner space where the other axial side is closed by the shield member, both axial ends of the braking member are supported simultaneously by the axial side surface of the outer member and the axial side surface of the shield member, by either the axial side surface of the outer member or the axial side surface of the shield member and the biasing means, or by the biasing means arranged on both axial sides. Since the inner member is in close contact with the braking member, when both axial ends of the braking member are supported simultaneously in the inner space, the inner member is also supported in the inner space without axial play. That is, the inner member is supported via the braking member. At this time, since the inner member is not axially biased, there is no change in the so-called hitting strength between the inner member and the outer member or the shield member, that is, the magnitude of the resistance caused by the friction between the inner member and the outer member or the shield member. Also, since the required braking torque is set between the inner member and the braking member, the magnitude of the required braking torque does not change. Therefore, the variation in the required braking torque between individuals is suppressed.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] Hereinafter, with reference to the accompanying drawings showing preferred embodiments of a torque limiter configured according to the present invention, it will be described in more detail. In the following description, the “one side” and “the other side” in the axial direction are, unless otherwise specified, based on the state shown in the A-A cross section of FIG. 1, where the “one side” is the left side in the figure and the “the other side” is the right side in the figure.

[0017] FIG. 1 shows the configuration of a preferred embodiment of a torque limiter configured according to a first aspect of the present invention. The torque limiter, indicated as a whole by the number 2a, includes an outer member 4a, an inner member 6a, a braking member 8a, and a shield member 10a, and has a common central axis o. In the B-B cross-sectional view of FIG. 1, the braking member 8a is shaded for easy understanding.

[0018] Referring to FIG. 2 together with FIG. 1, the outer member 4a made of synthetic resin has a circular end plate 12a disposed perpendicular to the axial direction and a cylindrical outer peripheral wall 14a extending from the outer peripheral edge of the end plate 12a toward the other side in the axial direction. An inner space 16a is formed inside the outer peripheral wall 14a. That is, one side in the axial direction of the inner space 16a is closed while the other side is open. A circular through hole 18a penetrating in the axial direction is formed at the center of the end plate 12a. Four arc-shaped recesses 20a 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 12a. A circular support recess 22a is formed at the central portion of the other axial side surface of the end plate 12a, and an annular support ridge 24a surrounding the outer peripheral edge of the through hole 18a is formed on the bottom surface of the support recess 22a. Six concave grooves 26a having an arcuate cross section extending linearly over the entire axial direction are formed on the outer peripheral surface of the outer peripheral wall 14a at equal angular intervals in the circumferential direction. A pair of locking walls having an arcuate cross section extending axially to a required extent from the other axial side surface of the end plate 12a are provided at intervals in the circumferential direction on the inner peripheral surface of the outer peripheral wall 14a (each locking wall is denoted by 28a1 and 28a2), and a pair of gaps 30a1 and 30a2 exist between the pair of locking walls 28a1 and 28a2. An annular locking groove 32a extending in the circumferential direction is formed at the other axial end portion of the inner peripheral surface of the outer peripheral wall 14a.

[0019] Referring to FIG. 3 together with FIG. 1, the inner member 6a made of metal is cylindrical. In the illustrated embodiment, the outer peripheral surface of the inner member 6a is cylindrical. An annular supported ridge 34a is formed at the outer peripheral edge portion of one axial side surface of the inner member 6a. A female engaging portion 36a formed of serrations is formed at a portion of the inner peripheral surface of the inner member 6a excluding the other axial end portion, and a female locking portion 38a formed of splines is formed at one axial end portion.

[0020] Referring to FIG. 1, in the illustrated embodiment, the braking member 8a is a coil spring (hereinafter, the coil spring may also be denoted by the number 8), and includes a winding portion 40a in which a metal wire is spirally wound and a pair of hook portions 42a1 and 42a2 that extend radially outward from the winding portion 40a. The winding portion 40a is attached to the outer peripheral surface of the inner member 6a. The coil spring 8a may be either a compression coil spring or a tension coil spring. The inner diameter of the winding portion 40a in the free state where no load is applied to the coil spring 8a is smaller than the diameter of the outer peripheral surface of the inner member 6a (in other words, the diameter of the outer peripheral surface of the inner member 6a is larger than the inner diameter of the winding portion 40a when the coil spring is in the free state), and the coil spring 8a is attached in close contact with the outer peripheral surface of the inner member 6a in a state where the inner diameter of the winding portion 40a is expanded. The pair of hook portions 42a1 and 42a2 are constituted by both ends of the wire. Therefore, the pair of hook portions 42a1 and 42a2 are respectively provided at both axial ends of the winding portion 40a.

[0021] Continuing the description with reference to FIG. 1, the inner member 6a and the coil spring 8a (braking member) are housed in the inner space 16a of the outer member 4a. At this time, the outer peripheral surface of one axial end portion of the inner member 6a is supported radially outward by the inner peripheral surface of the outer member 4a that defines the support recess 22a, and the inner peripheral surface of the supported ridge 34a of the inner member 6a is supported radially inward by the outer peripheral surface of the support ridge 24a of the outer member 4a. The outer surface of the winding portion 40a of the coil spring 8a faces the inner peripheral surfaces of the pair of locking walls 28a1 and 28a2, and the pair of hook portions 42a1 and 42a2 are commonly fitted into the gap 30a1. Thus, the coil spring 8a is supported in a non-rotatable state with respect to the outer member 4a.

[0022] Referring to FIG. 4 together with FIG. 1, the shield member 10a made of synthetic resin includes a circular shield plate 44a disposed perpendicular to the axial direction. A circular through hole 46a penetrating in the axial direction is formed at the center of the shield plate 44a. An annular support wall 48a surrounding the outer peripheral edge of the through hole 46a is formed on one axial side surface of the shield plate 44a. A cylindrical mounting wall 50a extending axially from the outer peripheral edge is formed on the other axial side surface of the shield plate 44a. An annular circumferential groove 52a open toward the other axial side is formed in the mounting wall 50a, and six ribs 54a are arranged in the circumferential direction at equal angular intervals in the circumferential groove 52a. An annular locking protrusion 56a extending in the circumferential direction is formed on the outer peripheral surface of the mounting wall 50a, and the shield member 10a is combined with the outer member 4a by locking the locking protrusion 56a to a locking groove 32a formed on the inner peripheral surface of the outer peripheral wall 14a of the outer member 4a, thereby closing the other axial side of the inner space 16a. Thus, as shown in the cross-sectional view taken along line A-A of FIG. 1, one axial side surface of the shield plate 44a axially supports the other axial side surface of the inner member 6a, and the inner peripheral surface of the support wall 48a radially supports the outer peripheral surface of the other axial side end of the inner member 6a. However, the axial length of the inner space 16a whose other axial side is closed by the shield member 10a is longer than the axial length of the inner member 6a. The above-mentioned "axial length of the inner space 16a whose other axial side is closed by the shield member 10a" is the length from the bottom surface of the support recess 22a of the outer member 4a to one axial side surface of the shield plate 44a of the shield member 10a. In the illustrated embodiment, it is the axial length from the portion excluding the support protrusion 24a on the other axial side surface of the support recess 22a to the portion excluding the support wall 48a on one axial side surface of the shield plate 44a.

[0023] In the torque limiter configured according to the first aspect of the present invention, the inner member 6a is axially biased with respect to the outer member 4a and the shield member 10a by a biasing means elasticallyIt is important that it is biased. In the illustrated embodiment, the biasing means is a wave washer 58a housed in the inner space 16a, which is disposed inside the support ridge 24a of the outer member 4a and biases the inner member 6a axially toward the other side. If desired, the wave washer 58a may be disposed outside the support ridge 24a.

[0024] At this time, in the torque limiter configured according to the first aspect of the present invention, the inner member 6a is axially biased with respect to the outer member 4a and the shield member 10a by the wave washer 58a which is the biasing means. elastically By being biased, in the inner space 16a whose axial other side is closed by the shield member 10a, both axial ends of the inner member 6a are simultaneously supported by the wave washer 58a and the axial side surfaces of the shield member 10a, so that the generation of abnormal noise due to axial play is prevented. In this aspect, since it is only necessary that the inner member 6a is axially biased with respect to the outer member 4a and the shield member 10a by the biasing means, the braking member may be of any type. That is, the coil spring 8a may be in close contact with the inner peripheral surface of the outer member 4a instead of the outer peripheral surface of the inner member 6a. When the coil spring 8a is in close contact with the inner peripheral surface of the outer member 4a, the gap (30a1) into which the pair of hook portions 42a1 and 42a2 are fitted is formed on the outer peripheral surface of the inner member. Further, since it is only necessary that the braking member imparts a braking torque to the relative rotation between the outer member 4a and the inner member 6a, other means such as a leaf spring or a tolerance ring may be used instead of the coil spring. Furthermore, the biasing means may be disposed between the inner member 6a and the shield member 10a. In this case, both axial ends of the inner member 6a are simultaneously supported by the biasing means and the axial side surface of the outer member 4a. Also, the biasing means may be disposed on both axial sides of the inner member 6a, that is, between the inner member 6a and the outer member 4a and between the inner member 6a and the shield member 10a. In this case, both axial ends of the inner member 6a are simultaneously supported by the biasing means.

[0025] Here, in the illustrated embodiment, the outer member 4a is a fixed housing held via the recess 20a and the concave groove 26a, and the inner member 6a is connected to an external device and used as an angular position holding device. A male locking portion 102 formed of a spline of a connecting member 100 shown by a two-dot chain line in FIG. 1 is locked to the female locking portion 38a of the inner member 6a, and the inner member 6a and the connecting member 100 rotate integrally. A male engaging portion 104 is further formed coaxially with the female engaging portion 36a of the inner member 6a on the connecting member 100. Then, either one of the female engaging portion 36a of the inner member 6a and the male engaging portion 104 of the connecting member 100 is connected to an input-side device such as an electric motor (not shown), and the other is connected to an output-side device such as a vehicle hatchback (not shown). Therefore, when rotational torque is applied from the input-side device, the inner member 6a tries to rotate together with the coil spring 8a. At this time, as described above, since the coil spring 8a cannot rotate with respect to the outer member 4a, either one of the pair of hook portions 42a1 and 42a2 is pushed in a direction in which the coil spring 8a is loosened by the circumferential side surface of either one of the pair of locking walls 28a1 and 28a2 within the gap 30a1 formed in the outer member 4a, and the inner member 6a rotates with respect to the coil spring 8a against the required braking torque by the tightening force of the coil spring 8a. 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 inner member 6a is held by the required braking torque by the coil spring 8a. Thus, the angular position of the output-side device is held.

[0026] Subsequently, a torque limiter configured according to the second aspect of the present invention will be described. In the torque limiter configured according to the first aspect of the present invention described above, the inner member was axially biased with respect to the outer member and the shield member by the biasing means. elastically However, in the torque limiter configured according to the second aspect of the present invention described below, the braking member in close contact with the inner member is axially biased with respect to the outer member and the shield member. elasticallyIn terms of biasing, the torque limiter configured according to the second aspect of the present invention is different from the torque limiter configured according to the first aspect of the present invention. Figures 5 to 7 respectively show the first to third embodiments of the torque limiter configured according to the second aspect of the present invention. Since the overall configuration of the torque limiters according to the illustrated first to third embodiments is the same as that of the torque limiter shown in Figure 1, in the following description, the same components are respectively assigned the same numbers with any of the letters b to d (b in the first embodiment, c in the second embodiment, and d in the third embodiment), and detailed descriptions thereof are omitted, and only the different components will be described. In the illustrated first to third embodiments, a coil spring is also adopted as the braking member. Therefore, when the coil spring is in a free state, the inner diameter of the winding portion is smaller than the outer diameter of the inner member, and the coil spring is mounted with the inner peripheral surface of the winding portion in close contact with the outer peripheral surface of the inner member. In Figures 5 to 7, the shield members 10b to 10d are separated from the outer members 4b to 4d for reasons of convenience, but in reality, they are combined by locking with the locking ridges 56b to 56d and the locking grooves 32b to 32d.

[0027] In the torque limiter 2b shown in Figure 5, the braking member 8b is a compression coil spring. Therefore, when in a free state, the wire rods constituting the winding portion 40b have a gap in the axial direction. After the inner member 6b and the compression coil spring 8b are accommodated in the inner space 16b and the other axial side of the inner space 16b is closed by the shield member 10b, the compression coil spring 8b is compressed from both axial sides by the outer member 4b and the shield member 10b. In the illustrated embodiment, the other axial side of the compression coil spring 8b is pressed axially by the support wall 48b of the shield member 10b. Thus, both ends of the compression coil spring 8b are simultaneously supported from both axial sides by the axial side surfaces of the outer member 4b and the axial side surface of the shield member 10b.

[0028] In the torque limiter 2c shown in FIG. 6, a biasing means 58c for axially biasing the coil spring 8c is integrally formed on the shield member 10c. In the illustrated embodiment, the coil spring 8c is a tension coil spring, but it may be a compression coil spring. The biasing means 58c is a wave-shaped elastic piece formed on one axial side surface of the shield plate 44c. When the inner member 6c and the coil spring 8c are housed in the inner space 16c and then the other axial side of the inner space 16c is closed by the shield member 10c, the biasing means 58c abuts against the other axial end of the coil spring 8c and presses it axially to one side. Both axial ends of the coil spring 8c are simultaneously supported from both axial sides by the other axial side surface of the end plate 12c of the outer member 4c and the biasing means 58c. If desired, in this embodiment, the biasing means 58c may be integrally formed on the outer member 4c instead of the shield member 10c. In this case, both axial ends of the coil spring 8c are simultaneously supported from both axial sides by the biasing means and one axial side surface of the shield member. Further, the biasing means 58c may be integrally formed not only on the shield member 10c but also on the outer member 4c. In this case, both axial ends of the inner member 6c are simultaneously supported from both axial sides by the biasing means 58d.

[0029] In the torque limiter 2d shown in FIG. 7, a biasing means 58d for axially biasing the coil spring 8d is accommodated in the inner space 16d. In the illustrated embodiment, the coil spring 8d is a tension coil spring, but it may be a compression coil spring. The biasing means 58d is a rubber-like ring disposed between the axially opposite side surface of the end plate 12d of the outer member 4d and the coil spring 8d. When the axially opposite side of the inner space 16d is closed by the shield member 10d after the inner member 6d and the coil spring 8d are accommodated in the inner space 16d, the biasing means 58d abuts against one axially side end of the coil spring 8d and presses it axially to the other side. Both axially ends of the coil spring 8d are simultaneously supported from both axially sides by the biasing means 58d and the axially one side surface of the support wall 48d of the shield member 10d. If desired, in this embodiment, the biasing means 58d may be disposed between the axially side surface of the support wall 48d of the shield member 10d and the coil spring 8d. In this case, both axially ends of the coil spring 8d are simultaneously supported from both axially sides by the axially opposite side surface of the outer member and the biasing means. Further, the biasing means 58d may be disposed on both axially sides of the inner member 6d, that is, between the inner member 6d and the outer member 4d and between the inner member 6d and the shield member 10d. In this case, both axially ends of the inner member 6d are simultaneously supported by the biasing means 58d.

[0030] In the torque limiter configured according to the second aspect of the present invention, the braking members 8b to 8d are axially elasticallyBy being biased, in the inner spaces 16b to 16d whose axial other sides are closed by the shield members 10b to 10d, both axial ends of the braking member 8b are by the axial side surfaces of the outer member 4b and the shield member 10b, and both axial ends of the braking members 8c and 8d are by either one of the axial side surfaces of the outer members 4c and 4d and the shield members 10c and 10d and the biasing means 58c and 58d or are simultaneously supported by the biasing means 58c and 58d arranged on both axial sides. Since the inner members 6b to 6d are in close contact with the braking members 8b to 8d, when both axial ends of the braking members 8b to 8d are simultaneously supported in the inner spaces 16b to 16d, the inner members 6b to 6d are also supported in the inner spaces 16b to 16d without axial play. That is, the inner members 6b to 6d are supported via the braking members 8b to 8d. At this time, since the inner members 6b to 6d are not axially biased, there is no change in the so-called hitting strength between the inner members 6b to 6d and the outer members 4b to 4d and the shield members 10b to 10d, that is, the magnitude of the resistance caused by the friction between the inner members 6b to 6d and the outer members 4b to 4d and the shield members 10b to 10d, and also, since the required braking torque is set between the inner members 6b to 6d and the braking members 8b to 8d, the magnitude of the required braking torque does not change either. Therefore, the variation in the required braking torque between individuals is suppressed. In the second and third embodiments in this aspect, the braking member may be in any form as long as it is in close contact with the inner members 6b to 6d, and thus, it may be a leaf spring, a tolerance ring, or the like.

[0031] As described above, the torque limiter 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, the case where the torque limiter is used as an angular position holding device, that is, the case where the outer member is fixed has been described, but there may be a case where the outer member rotates.

Explanation of Reference Numerals

[0032] 2a to 2d: Torque limiter 4a to 4d: Outer member 6a to 6d: Inner member 8a to 8d: Braking member 10a to 10d: Shield member 16a to 16d: Inner space 58a, 58c, 58d: Biasing means

Claims

1. An outer member having an inner space that is closed on one axial side and open on the other side, an inner member and a braking member accommodated in the inner space, and a shield member that is combined with the outer member after the inner member and the braking member are accommodated in the inner space to close the other side of the inner space, wherein the axial length of the inner space closed by the shield member is longer than the axial length of the inner member, wherein the outer member and the inner member are relatively rotatable, and the braking member is disposed between the outer member and the inner member and is a torque limiter that applies a required braking torque to the relative rotation, wherein the inner member is axially biased with respect to the outer member and the shield member by a biasing means, a torque limiter characterized by this.

2. The torque limiter according to claim 1, wherein the biasing means is a wave washer accommodated in the inner space.

3. An outer member having an inner space that is closed on one axial side and open on the other side, an inner member and a braking member accommodated in the inner space, and a shield member that is combined with the outer member after the inner member and the braking member are accommodated in the inner space to close the other side of the inner space, wherein the axial length of the inner space closed by the shield member is longer than the axial length of the inner member, wherein the outer member and the inner member are relatively rotatable, and the braking member is disposed between the outer member and the inner member and is a torque limiter that applies a required braking torque to the relative rotation, wherein the braking member is in close contact with the inner member and is axially biased with respect to the outer member and the shield member, a torque limiter characterized by this.

4. The braking member is a compression coil spring that is compressed from both axial sides by the outer member and the shield member, and includes a winding portion around which a wire is wound and a hook portion that extends in a direction away from the winding portion of the wire, wherein the outer peripheral surface of the inner member is cylindrical, the winding portion of the compression coil spring is mounted on the outer peripheral surface, and the diameter of the outer peripheral surface is larger than the inner diameter of the winding portion when the compression coil spring is in a free state, the torque limiter according to claim 3.

5. The braking member is a coil spring and includes a winding portion around which a wire is wound and a hook portion extending in a direction in which the wire is separated from the winding portion. The outer peripheral surface of the inner member is cylindrical, the winding portion of the coil spring is mounted on the outer peripheral surface, and the diameter of the outer peripheral surface is larger than the inner diameter of the winding portion when the coil spring is in a free state. The torque limiter according to claim 3, wherein biasing means for axially biasing the coil spring is integrally formed on the shield member and / or the outer member.

6. The braking member is a coil spring and includes a winding portion around which a wire is wound and a hook portion extending in a direction in which the wire is separated from the winding portion. The outer peripheral surface of the inner member is cylindrical, the winding portion of the coil spring is mounted on the outer peripheral surface, and the diameter of the outer peripheral surface is larger than the inner diameter of the winding portion when the coil spring is in a free state. The torque limiter according to claim 3, wherein biasing means for axially biasing the coil spring is also accommodated in the inner space.

7. The outer member is a fixed housing, and the inner member is connected to an external device and used as an angular position holding device. The torque limiter according to any one of claims 1 to 6.

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