Brake device

Abstract

To provide a brake device easily suppressing power consumption or easily downsized.SOLUTION: A brake device 1 includes a shaft 2, a wrap spring unit 3, a stator 4, an electromagnetic coil 5, a magnetic part 6, a friction plate 7, a side plate 8, a hub 9, and a pressing member 10. The wrap spring unit 3 includes a wrap spring 30 and a tongue 31. The pressing member 10 presses the side plate 8 and the magnetic plate 6 to the friction plate 7. The hub 9 includes a bearing part 90, a connection part 91 and a stopper part. The tongue 31 moves to a direction extending the inner diameter of the wrap spring 30 to release the shaft 2 when the electromagnetic coil 5 is energized. The tongue 31 moves in a direction narrowing the inner diameter of the wrap spring 30, and abuts to the stopper part and the rotation is regulated to brake the shaft 2 at the time of non-energization of the electromagnetic coil 5. The pressing member 10 is disposed to the outside of the stator 4.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a brake device, and more particularly to a brake device having a wrap spring unit wrapped around a shaft. [Background technology]

[0002] Patent document 1 describes a negative action brake as a means for quickly stopping the motor shaft when the power supply to the motor is suddenly stopped, or for fixing the motor shaft when the motor is not powered.

[0003] This negative action brake includes a brake disc that is attached to the motor shaft in a state where it is constrained in the rotational direction (i.e., so as to rotate integrally with the motor shaft), an armature that is movable in the axial direction of the motor shaft, and a spring that presses the armature against the brake disc. The negative action brake also includes a side plate that sandwiches the brake disc between the armature and the side plate, and a coil that attracts the armature when energized, thereby separating the armature from the brake disc.

[0004] In this negative action brake, when the coil is energized, the armature overcomes the pressing force of the spring and is attracted to the brake disc, releasing the brake. When the coil is de-energized, the armature is pressed against the brake disc by the force of the spring, applying the brake. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-152560 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the negative action brake described in Patent Document 1, a spring is arranged in the inner peripheral portion of the stator of the coil (i.e., inside the stator), which limits the space available for arranging the coil. As a result, this negative action brake has the problem of consuming a lot of power to generate the magnetic attraction force required to attract the armature.

[0007] In view of the above circumstances, an object of the present disclosure is to provide a brake device that can easily reduce power consumption or can be easily made smaller. [Means for solving the problem]

[0008] A brake device according to one aspect of the present disclosure includes a shaft extending in one direction, a wrap spring unit, an annular stator surrounding the wrap spring unit, and an electromagnetic coil built into the stator. The wrap spring unit includes a wrap spring wound around the shaft and a pair of magnetic tongues fixed to both ends of the wrap spring in the winding direction. The brake device further includes an annular magnetic portion and an annular friction plate aligned in the one direction relative to the stator, a side plate capable of sandwiching the friction plate between the magnetic portion, a hub, and a pressing member. The hub has a bearing portion that rotatably supports the shaft, a connecting portion that is non-rotatably connected to the friction plate, and a stopper portion located between the pair of tongues. The pressing member presses the side plate and the magnetic portion against the friction plate. When the electromagnetic coil is energized, the pair of tongues move in a direction that expands the inner diameter of the wrap spring due to the magnetic attraction force of the electromagnetic coil, thereby releasing the shaft. When the electromagnetic coil is de-energized, the pair of tongues move in a direction narrowing the inner diameter of the wrap spring due to the spring force of the wrap spring, causing the wrap spring to wrap around the shaft and become one with it. The pair of tongues, which rotate integrally with the shaft, then hit the stopper portion, restricting their rotation, thereby applying a brake to the shaft. The pressing member is disposed outside the stator.

[0009] According to another aspect of the present disclosure, a brake device includes a shaft extending in one direction, a wrap spring unit, an annular stator surrounding the wrap spring unit, and an electromagnetic coil built into the stator. The wrap spring unit includes a wrap spring wound around the shaft and a pair of magnetic tongues fixed to both ends of the wrap spring in the winding direction. The brake device further includes an annular friction plate and side plate aligned in the one direction relative to the stator, a hub, and a pressing member that presses the friction plate against the side plate. The hub includes a bearing portion that rotatably supports the shaft, a connecting portion that is non-rotatably connected to the friction plate, and a stopper portion located between the pair of tongues. When the electromagnetic coil is energized, the pair of tongues move in a direction that expands the inner diameter of the wrap spring due to the magnetic attraction force of the electromagnetic coil, thereby releasing the shaft. In the brake device, when the electromagnetic coil is de-energized, the pair of tongues move in a direction narrowing the inner diameter of the wrap spring due to the spring force of the wrap spring, causing the wrap spring to wrap around and become one with the shaft. The pair of tongues, which rotate integrally with the shaft, then hit the stopper portion, restricting their rotation, thereby applying a brake to the shaft. The pressing member is composed of a spring embedded in a portion of the hub and pressing the friction plate against the side plate. [Effects of the Invention]

[0010] In the brake device according to one aspect and another aspect of the present disclosure, it is easy to reduce power consumption or to achieve miniaturization. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a brake device according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 3 is an exploded perspective view showing the brake device. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a main part of the brake device. [Figure 5] FIG. 5 is a cross-sectional view that schematically shows a main part of a brake device according to a second embodiment of the present disclosure. [Figure 6] FIG. 6 is a side view showing a magnetic portion provided in the brake device. [Figure 7] FIG. 7 is a cross-sectional view that schematically shows a main part of a brake device according to a third embodiment of the present disclosure. [Figure 8] FIG. 8 is a cross-sectional view that schematically shows a main part of a brake device according to a fourth embodiment of the present disclosure. [Figure 9] FIG. 9 is a cross-sectional view that schematically shows a main part of a brake device according to a fifth embodiment of the present disclosure. [Figure 10] FIG. 10 is a cross-sectional view that schematically shows a main part of a brake device according to a sixth embodiment of the present disclosure. [Figure 11] FIG. 11 is a cross-sectional view that schematically shows a main part of a brake device according to a seventh embodiment of the present disclosure. [Figure 12] FIG. 12 is a side view showing a modified example of the magnetic portion of the brake device of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Embodiment 1) 1. Overview 1 to 4, the brake device 1 of the first embodiment includes a shaft 2 extending in one direction D1, a wrap spring unit 3, an annular stator 4 surrounding the wrap spring unit 3, and an electromagnetic coil 5 built into the stator 4. The wrap spring unit 3 includes a wrap spring 30 wound around the shaft 2 and a pair of magnetic tongues 31 fixed to both ends of the wrap spring 30 in the winding direction. The brake device 1 further includes an annular magnetic portion 6 and an annular friction plate 7 aligned in one direction relative to the stator 4, a side plate 8 capable of sandwiching the friction plate 7 between the magnetic portion 6, a hub 9, and a pressing member 10 that presses the side plate 8 and the magnetic portion 6 against the friction plate 7. The hub 9 includes a bearing portion 90 that rotatably supports the shaft 2, a connecting portion 91 that is connected to the friction plate 7 so as not to rotate relative to the side plate 8, and a stopper portion 92 located between the pair of tongues 31. When the electromagnetic coil 5 is energized, the brake device 1 releases the shaft 2 by causing the pair of tongues 31 to move in a direction that increases the inner diameter of the wrap spring 30 due to the magnetic attraction force of the electromagnetic coil 5. When the electromagnetic coil 5 is not energized, the brake device 1 causes the pair of tongues 31 to move in a direction that decreases the inner diameter of the wrap spring 30 due to the spring force of the wrap spring 30, causing the wrap spring 30 to wrap around and become one with the shaft 2. Then, the pair of tongues 31, which rotate integrally with the shaft 2, come into contact with the stopper portion 92, restricting their rotation, thereby applying a brake to the shaft 2. The pressing member 10 is disposed outside the stator 4.

[0013] In the brake device 1 of embodiment 1 having the above configuration, the pressing member 10 is disposed outside the stator 4, and therefore the winding area of ​​the electromagnetic coil 5 inside the stator 4 can be easily increased in the radial direction of the shaft 2. Therefore, in the brake device 1 of embodiment 1, it is easy to reduce the power consumption required to obtain the magnetic attraction force required to attract the pair of tongues 31. Alternatively, in the brake device 1 of embodiment 1, the winding area of ​​the electromagnetic coil 5 inside the stator 4 can be increased in the radial direction of the shaft 2, and therefore it is easy to reduce the winding area of ​​the electromagnetic coil 5 in one direction D1, and it is easy to miniaturize the electromagnetic coil 5 and the stator 4 in one direction D1.

[0014] 2.Details Next, the brake device 1 of the first embodiment shown in Figures 1 to 4 will be described in more detail with reference to the drawings. The brake device 1 is mounted on a motor for an articulated robot, for example, and is used to hold the robot arm when the power is turned off or for emergency braking in case of danger.

[0015] The brake device 1 includes a shaft 2, a wrap spring unit 3, a stator 4, an electromagnetic coil 5, a magnetic portion 6, a friction plate 7, a side plate 8, a hub 9, and a pressing member 10.

[0016] 2-1. Shaft The shaft 2 is a rod-shaped member extending in one direction D1. The shaft 2 is rotatable around its central axis. The wrap spring unit 3 is wound around the shaft 2, and the shaft 2 is supported by a hub 9 so as to be rotatable or non-rotatable.

[0017] 2-2. Wrap spring unit As shown in FIGS. 2 and 3, the wrap spring unit 3 includes a wrap spring 30 wound around the shaft 2, and a pair of tongues 31 fixed to both ends of the wrap spring 30 in the winding direction.

[0018] The wrap spring unit 3 is configured so that, when the electromagnetic coil 5 is energized, the pair of tongues 31 move in a direction that expands the inner diameter of the wrap spring 30 due to the magnetic attraction force of the electromagnetic coil 5, thereby releasing the shaft 2. Furthermore, the wrap spring unit 3 is configured so that, when the electromagnetic coil 5 is not energized, the pair of tongues 31 move in a direction that narrows the inner diameter of the wrap spring 30 due to the spring force of the wrap spring 30, thereby causing the wrap spring 30 to wrap around the shaft 2.

[0019] In this embodiment, the wrap spring 30 has a spiral main body portion 300 wound around the shaft 2, and a pair of arm portions 301 extending linearly from one end and the other end of the winding direction of the main body portion 300 and fixed to a pair of tangs 31.

[0020] The wrap spring 30 has a rectangular cross section perpendicular to the winding direction. The main body 300 is a cylindrical coil spring. The main body 300 is spirally wound so as to be in frictional contact with the shaft 2, and is attached coaxially to the shaft 2.

[0021] The pair of arm portions 301 extend linearly from one end and the other end of the main body portion 300 in the winding direction so as to be parallel to the tangent lines at these ends. The pair of arm portions 301 are positioned at a distance in one direction D1 (i.e., the axial direction of the shaft 2). When viewed in the one direction D1, the pair of arm portions 301 protrude to the same side from the main body portion 300. When viewed in the one direction D1, the pair of arm portions 301 extend linearly so that the distance between them becomes narrower towards the tip end.

[0022] Each of the pair of tongues 31 is made of a magnetic material. Each of the pair of tongues 31 has an arc shape that follows the inner circumferential surface of the stator 4. In this embodiment, the pair of tongues 31 have the same size and shape and are provided point-symmetrically. The pair of tongues 31 have arm portions 301 fixed to their ends on the same side when viewed in one direction D1.

[0023] Each of the pair of tongues 31 has a length in the one direction D1 that is approximately the same as that of the wrap spring 30. One of the tongues 31 has an arm portion 301 fixed to one end in the one direction D1, and the other tongue 31 has an arm portion 301 fixed to the other end in the one direction D1.

[0024] In this embodiment, when the electromagnetic coil 5 is energized, the magnetic attraction force of the electromagnetic coil 5 causes the pair of tongues 31 to move radially outward from the shaft 2 so as to increase the gap between the tip ends of the pair of arm portions 301, thereby increasing the inner diameter of the wrap spring 30. When the electromagnetic coil 5 is not energized, the magnetic attraction force of the electromagnetic coil 5 no longer acts on the pair of tongues 31, and the spring force of the wrap spring 30 causes the pair of tongues 31 to move radially inward from the shaft 2 so as to decrease the gap between the tip ends of the pair of arm portions 301. This decreases the inner diameter of the wrap spring 30, causing the wrap spring 30 to wrap around the shaft 2. When the wrap spring 30 is wound around the shaft 2, the wrap spring unit 3 rotates integrally with the shaft 2.

[0025] 2-3. Stator and electromagnetic coil 1 to 4 is an annular member that surrounds the wrap spring unit 3. The stator 4 is made of a magnetic material. An electromagnetic coil 5 is built into the stator 4.

[0026] In this embodiment, the stator 4 has a base portion 40 that is annular when viewed in one direction D1, and a peripheral wall portion 41 that protrudes from the outer periphery of the base portion 40 to one side in the one direction D1. The stator 4 further has an inner cylindrical portion 42 that is arranged inside the electromagnetic coil 5 in the radial direction of the shaft 2. The inner cylindrical portion 42 is a separate member from the base portion 40 and is used in combination with the base portion 40. The electromagnetic coil 5 is housed in a space surrounded by the base portion 40, the peripheral wall portion 41, and the inner cylindrical portion 42 (see FIG. 2). The stator 4 does not necessarily have to have the inner cylindrical portion 42.

[0027] As shown in Fig. 3, the electromagnetic coil 5 is provided in an annular shape when viewed in one direction D1. The inner circumferential surface and both surfaces of the electromagnetic coil 5 in the one direction D1 are covered with insulating members. When energized, the electromagnetic coil 5 generates a magnetic attraction force in a direction that attracts the pair of tongues 31 (i.e., radially outward from the shaft 2). In this embodiment, the electromagnetic coil 5 can be arranged in the stator 4 with an expanded winding area so as to extend from the radially inner end to the radially outer end of the stator 4.

[0028] 2-4.Magnetic part As shown in FIGS. 1 and 2, the magnetic portion 6 is an annular member that is aligned with the stator 4 in one direction D1.

[0029] In this embodiment, the magnetic portion 6 has a main body portion 60 that is annular when viewed in one direction D1, and a plurality of protrusions 61 that protrude from the outer peripheral surface of the main body portion 60. The plurality of protrusions 61 are positioned at intervals (equally spaced in this embodiment) in the circumferential direction.

[0030] The main body 60 is positioned so as to cover the electromagnetic coil 5 from one side in the direction D1. The plurality of protrusions 61 face the peripheral wall 41 of the stator 4.

[0031] 2-5.Friction plate The friction plate 7 is connected to the hub 9 so as to be movable in one direction D1 but non-rotatable relative to the hub 9. The friction plate 7 has an annular main body 70 having a fitting hole 700 into which the connecting portion 91 of the hub 9 fits, and a pair of annular ring portions 71 attached to both sides of the main body 70 in the one direction D1. The main body 70 is made of metal. The pair of ring portions 71 are formed of a friction material. Note that the main body 70 of the friction plate 7 may also be formed of a friction material.

[0032] The fitting hole 700 has a rectangular shape with four chamfered corners when viewed in the direction D1. The outer peripheral surface of the main body 70 is circular. The connecting portion 91 of the hub 9 is connected to the fitting hole 700 so as to be movable in the direction D1 but not rotatable relative to the fitting hole 700.

[0033] 2-6.Side plate The side plate 8 is a member capable of sandwiching the friction plate 7 between itself and the magnetic part 6. The side plate 8 is made of, for example, metal.

[0034] In this embodiment, the side plate 8 is an annular plate when viewed in the direction D1. The inner peripheral portion of the surface of the side plate 8 facing one side in the direction D1 faces the friction plate 7.

[0035] The side plate 8 is provided with a plurality of insertion holes 80 through which fasteners 11 such as screws are inserted to fix the side plate 8 to the stator 4. The plurality of insertion holes 80 are positioned at intervals in the circumferential direction (at equal intervals in this embodiment). Each of the plurality of insertion holes 80 penetrates the outer peripheral portion of the side plate 8 in one direction D1.

[0036] Hub The hub 9 is attached to a part of the shaft 2 in one direction D1, and supports the shaft 2 so that it can rotate freely or non-rotatably.

[0037] As shown in Figures 2 and 3, the hub 9 has a bearing portion 90 that rotatably supports the shaft 2, a connecting portion 91 that is connected to the friction plate 7 so that it cannot rotate relative to the friction plate 7, and a stopper portion 92 that is located between the pair of tangs 31.

[0038] The hub 9 further has a base portion 93 that is positioned more inward than the stator 4 and is annular when viewed in one direction D1, and a guide portion 94 that is arc-shaped when viewed in one direction D1 and guides the movement of the pair of tongues 31.

[0039] The base portion 93 has a thickness in one direction D1. A bearing portion 90 is provided inside the annular base portion 93. The bearing portion 90 is a ball bearing. In this embodiment, the base portion 93 is disposed inside the ring portion 71 on one side of the friction plate 7 (more specifically, on the magnetic portion 6 side).

[0040] The connecting portion 91 protrudes from the base portion 93 toward one side in the direction D1. The connecting portion 91 has a shape that fits into the fitting hole 700 of the friction plate 7 so as not to rotate relative to the friction plate 7, and in this embodiment, is octagonal. The connecting portion 91 fits into the fitting hole 700 with four edge sides of the connecting portion 91 abutting against the inner circumferential surface of the rectangular fitting hole 700.

[0041] A stopper portion 92 and a guide portion 94 protrude from the base portion 93 toward the other side in the direction D1. The stopper portion 92 is provided on a portion of the circumference of the base portion 93. In this embodiment, the stopper portion 92 is a block having a rectangular cross section perpendicular to the direction D1.

[0042] The guide portion 94 is provided at a part of the circumferential direction of the inner circumferential end portion of the base portion 93. The circumferential center portion of the guide portion 94 is provided integrally with the stopper portion 92.

[0043] The hub 9 is positioned so that the connecting portion 91 fits into the fitting hole 700 of the friction plate 7, and the stopper portion 92 and the guide portion 94 are located inside the stator 4 and the magnetic portion 6. The shaft 2 is rotatably supported by the bearing portion 90.

[0044] The connecting portion 91 of the hub 9 is fitted into the fitting hole 700 of the friction plate 7, so that the hub 9 cannot rotate relative to the friction plate 7. When the friction plate 7 is sandwiched between the magnetic portion 6 and the side plate 8 and its rotation is restricted, the rotation of the hub 9 is restricted.

[0045] 1, the hub 9 is disposed so that the stopper portion 92 is located between the pair of tongues 31 of the wrap spring unit 3. A guide portion 94 is disposed between the main body portion 300 of the wrap spring 30 and the pair of tongues 31.

[0046] The hub 9 does not necessarily have to have the guide portion 94.

[0047] 2-8.Pressing member The pressing member 10 is a member that presses the side plate 8 and the magnetic portion 6 against the friction plate 7. In this embodiment, the pressing member 10 is arranged between the side plate 8 and the magnetic portion 6 and is composed of a magnet 10a that generates a magnetic force in a direction that attracts the side plate 8 and the magnetic portion 6. The magnet 10a is a permanent magnet.

[0048] In this embodiment, the brake device 1 further includes a spacer 12 that is disposed between the stator 4 and the side plate 8 and maintains a constant distance between the stator 4 and the side plate 8. A part of the spacer 12 constitutes the magnet 10a.

[0049] The spacer 12 has a spacer body 120 that is annular when viewed in one direction D1, and a plurality of protrusions 121 that protrude from the spacer body 120 to one side in the one direction D1 (more specifically, toward the stator 4). The plurality of protrusions 121 are arranged at intervals (more specifically, at equal intervals) in the circumferential direction.

[0050] Each of the multiple protrusions 121 has a through hole 122 that penetrates in one direction D1. The through hole 122 penetrates the protrusion 121 and the spacer main body 120. The spacer 12 is disposed between the side plate 8 and the stator 4, with the friction plate 7 disposed radially inside the spacer main body 120 and the protrusion 61 of the magnetic part 6 disposed between two protrusions 121 adjacent in the circumferential direction.

[0051] Fixing device 11 for fixing side plate 8 is inserted into insertion hole 80 of side plate 8 and through hole 122 of spacer 12, and fastened to peripheral wall portion 41 of stator 4, thereby attaching spacer 12 between side plate 8 and stator 4. Spacer body 120 contacts side plate 8, and multiple protrusions 121 contact peripheral wall portion 41 of stator 4.

[0052] The length of the plurality of protrusions 121 in one direction D1 is longer than the length of the protrusions 61 of the magnetic part 6 in one direction D1. Therefore, the magnetic part 6 is arranged so as to be movable in the one direction D1.

[0053] In this embodiment, the entire spacer body 120 is made up of the magnet 10a. Therefore, the portion of the spacer body 120 that faces the protrusion 61 of the magnetic part 6 is made up of the magnet 10a. Note that only the portion of the spacer body 120 that faces the protrusion 61 of the magnetic part 6 may be made up of the magnet 10a, or the entire spacer 12 may be made up of the magnet 10a.

[0054] The magnet 10a uses its magnetic force to attract the protruding portion 61 of the magnetic portion 6 to one side in one direction D1 (more specifically, to the side plate 8 side). This causes the magnetic portion 6 to move toward the side plate 8, and the friction plate 7, which is pushed by the magnetic portion 6, presses against the side plate 8, thereby sandwiching the friction plate 7 between the magnetic portion 6 and the side plate 8 and restricting the rotation of the friction plate 7, thereby restricting the rotation of the hub 9. As a result, the rotation of the hub 9 is always restricted (that is, regardless of whether the electromagnetic coil 5 is energized or not).

[0055] 3. Brake device operation Next, the operation of the above-mentioned brake device 1 will be described.

[0056] When the electromagnetic coil 5 starts to be energized, the magnetic attraction force of the electromagnetic coil 5 acts on the pair of tongues 31 , causing the pair of tongues 31 to move radially outward of the shaft 2 .

[0057] As a result, the pair of arms 301 of the wrap spring 30 are displaced in a direction that widens the gap between their tip ends, the inner diameter of the main body 300 of the wrap spring 30 widens, and a gap is formed between the main body 300 and the shaft 2. This releases the wrap spring unit 3 from its pressure-contact state with the shaft 2, and the brake on the shaft 2 is released.

[0058] When the electromagnetic coil 5 is de-energized, the magnetic attraction force of the electromagnetic coil 5 against the pair of tongues 31 ceases. Then, due to the spring force (more specifically, the restoring force) of the wrap spring 30, the pair of arm portions 301 of the wrap spring 30 are displaced in a direction narrowing the gap between their tips, narrowing the inner diameter of the main body portion 300, and the main body portion 300 is wrapped around and pressed against the shaft 2. At this time, the pair of tongues 31 are in contact with the stopper portion 92 of the hub 9 or positioned with a small gap therebetween. In this state, if the shaft 2 with the wrap spring unit 3 wrapped around it attempts to rotate, one of the pair of tongues 31 will come into contact with the stopper portion 92. Here, because the rotation of the hub 9 with the stopper portion 92 is restricted relative to the stator 4, the rotation of the shaft 2 is restricted by the hub 9. As a result, a brake is applied to the shaft 2 when the electromagnetic coil 5 is de-energized.

[0059] 4. Effects In the brake device 1 of this embodiment described above, the pressing member 10 (more specifically, the magnet 10a) that presses the side plate 8 and the magnetic portion 6 against the friction plate 7 is located outside the stator 4, not inside the stator 4 as in the conventional example.

[0060] Therefore, in the brake device 1 of this embodiment, it is easy to increase the winding area of ​​the electromagnetic coil 5 inside the stator 4 in the radial direction of the shaft 2. As a result, in the brake device 1 of this embodiment, it is easy to reduce the power consumption required to obtain the magnetic attraction force required to attract the pair of tongues 31. Alternatively, in the brake device 1 of this embodiment, because the winding area of ​​the electromagnetic coil 5 inside the stator 4 can be increased in the radial direction of the shaft 2, it is easy to reduce the winding area of ​​the electromagnetic coil 5 in one direction D1, and it is easy to miniaturize the electromagnetic coil 5 and the stator 4 in one direction D1.

[0061] Furthermore, in the brake device 1 of this embodiment, the magnetic force of the magnet 10a attracts the magnetic portion 6 toward the side plate 8, and the friction plate 7 is sandwiched between the side plate 8 and the magnetic portion 6, so that the rotation of the friction plate 7 and the hub 9 can be constantly restricted. Therefore, in the brake device 1 of this embodiment, when the electromagnetic coil 5 is not energized, the rotation of the shaft 2 around which the wrap spring unit 3 is wound can be stopped by the hub 9, and the shaft 2 can be braked.

[0062] (Embodiment 2) Next, the brake device 1 of the second embodiment shown in Figures 5 and 6 will be described in detail with reference to the drawings. In the following, the components of the brake device 1 of the second embodiment that are common to the first embodiment will be denoted by the same reference numerals in the drawings and detailed description will be omitted, and the components that differ from the first embodiment will be described in detail.

[0063] In the brake device 1 of the second embodiment, the pressing member 10 is configured by a magnet 10b that constitutes part of the magnetic portion 6 and generates a magnetic force in a direction that attracts the side plate 8 to the magnetic portion 6.

[0064] The brake device 1 of the second embodiment does not include the spacer 12. The side plate 8 has an annular plate body 81 when viewed in one direction D1, and an extension portion 82 that protrudes from a portion of the circumferential direction of the plate body 81 toward the magnet 10b. The protruding length of the extension portion 82 is set so as to create a gap between the side plate 8 and the magnet 10b. The side plate 8 is made of a magnetic material.

[0065] Some of the multiple protrusions 61 of the magnetic part 6 are configured with magnets 10b. In this embodiment, of the multiple protrusions 61, two protrusions 61 that protrude in opposite directions are configured with magnets 10b. Magnets 10b are permanent magnets.

[0066] In the brake device 1 of embodiment 2, the magnetic force of the magnet 10b can attract the side plate 8 toward the magnetic part 6, thereby sandwiching the friction plate 7 between the side plate 8 and the magnetic part 6 and restricting the rotation of the friction plate 7 and the hub 9.

[0067] Furthermore, in the brake device 1 of the second embodiment, the side plate 8 is provided with the extension 82 that protrudes toward the magnet 10b, which makes it easier for the side plate 8 to be attracted by the magnetic force of the magnet 10b.

[0068] (Embodiment 3) Next, the brake device 1 of the third embodiment shown in Fig. 7 will be described in detail with reference to the drawings. In the following, the components of the brake device 1 of the third embodiment that are common to the first embodiment will be denoted by the same reference numerals in the drawings and detailed description will be omitted, and the components that differ from the first embodiment will be described in detail.

[0069] In the brake device 1 of the third embodiment, the pressing member 10 is configured by a screw 10c that fastens the side plate 8 to the magnetic portion 6.

[0070] The side plate 8 is provided with an insertion hole 83 through which the screw 10c is inserted. The spacer body 120 of the spacer 12 is provided with an insertion hole 123 through which the screw 10c is inserted. The protruding portion 61 of the magnetic portion 6 is provided with a screw hole 610 through which the screw 10c is fastened. The screw hole 610 is a blind hole that does not pass through the protruding portion 61. Note that the screw hole 610 may also be a through hole that passes through the protruding portion 61.

[0071] The screw 10c is inserted through the insertion hole 83 of the side plate 8 and the insertion hole 123 of the spacer 12, and fastened to the screw hole 610 of the magnetic part 6. The magnetic part 6 is fixed to the side plate 8 in a state where it is pulled toward the side plate 8 by the screw 10c.

[0072] In the brake device 1 of embodiment 3, the magnetic part 6 can be pulled toward the side plate 8 by the screw 10c, and the friction plate 7 can be sandwiched between the magnetic part 6 and the side plate 8, thereby restricting the rotation of the friction plate 7 and the hub 9.

[0073] In the brake device 1 of the third embodiment, the magnetic portion 6 and the side plate 8 can be easily fixed in position, and the state in which the friction plate 7 is sandwiched between the magnetic portion 6 and the side plate 8 can be easily maintained.

[0074] (Embodiment 4) Next, the brake device 1 of the fourth embodiment shown in Fig. 8 will be described in detail with reference to the drawings. In the following, the components of the brake device 1 of the fourth embodiment that are common to the first embodiment will be denoted by the same reference numerals in the drawings and detailed description will be omitted, and the components that differ from the first embodiment will be described in detail.

[0075] In the brake device 1 of the fourth embodiment, the pressing member 10 is provided on the outer side of the side plate 8 in the one direction D1 and is composed of a spring 10d that presses the side plate 8 against the friction plate 7. The brake device 1 includes a receiving member 13 that is arranged on the outer side of the side plate 8 in the one direction D1. The receiving member 13 is provided with a recess 130 that accommodates the spring 10d. The brake device 1 of the fourth embodiment does not include a spacer 12 (see FIG. 3), and the side plate 8 is provided so as to be movable in the one direction D1.

[0076] The receiving member 13 is, for example, an annular plate when viewed in one direction D1. The receiving member 13 is provided with two recesses 130 aligned in the radial direction of the shaft 2. The receiving member 13 is provided with a plurality of sets of two recesses 130 spaced apart in the circumferential direction.

[0077] The receiving member 13 is attached to the outside of the side plate 8 by screws (not shown) that pass through the receiving member 13 and the side plate 8 and are fastened to the peripheral wall portion 41 of the stator 4 or the magnetic portion 6. The side plate 8 is pressed against the friction plate 7 by a spring 10d housed in a recess 130 of the receiving member 13.

[0078] In the brake device 1 of embodiment 4, the side plate 8 is pressed against the friction plate 7 by the spring 10d, so that the friction plate 7 can be sandwiched between the magnetic part 6 and the side plate 8, thereby restricting the rotation of the friction plate 7 and the hub 9.

[0079] (Embodiment 5) Next, the brake device 1 of the fifth embodiment shown in Fig. 9 will be described in detail with reference to the drawings. In the following, the components of the brake device 1 of the fifth embodiment that are common to the first embodiment will be denoted by the same reference numerals in the drawings and detailed description thereof will be omitted, and the components that differ from the first embodiment will be described in detail.

[0080] In the brake device 1 of the fifth embodiment, the pressing member 10 is arranged between the side plate 8 and the magnetic portion 6 and is configured with a spring 10e that biases the side plate 8 and the magnetic portion 6 in a direction that draws them together.

[0081] A through hole 124 for accommodating the spring 10e is provided in a portion of the spacer body 120 of the spacer 12 between two circumferentially adjacent protrusions 121 (see FIG. 3). The through hole 124 penetrates the spacer body 120 in one direction D1. A plurality of through holes 124 are provided in the spacer body 120 at intervals in the circumferential direction. A spring 10e is accommodated in each of the plurality of through holes 124.

[0082] One end of the spring 10e in the winding direction is fixed to the side plate 8, and the other end of the spring 10e in the winding direction is fixed to the protruding portion 61 of the magnetic portion 6. The spring 10e biases the side plate 8 and the magnetic portion 6 in a direction that attracts them to each other.

[0083] In the brake device 1 of embodiment 5, the spring 10e can pull the side plate 8 and the magnetic part 6 toward each other, thereby sandwiching the friction plate 7 between the side plate 8 and the magnetic part 6 and restricting the rotation of the friction plate 7 and the hub 9.

[0084] (Embodiment 6) Next, the brake device 1 of the sixth embodiment shown in Fig. 10 will be described in detail with reference to the drawings. In the following, the components of the brake device 1 of the sixth embodiment that are common to the first embodiment will be denoted by the same reference numerals in the drawings and detailed description will be omitted, and the components that differ from the first embodiment will be described in detail.

[0085] In the brake device 1 of the sixth embodiment, the pressing member 10 is embedded in a part of the hub 9 and is composed of a magnet 10f that generates a magnetic force in a direction that attracts the side plate 8 and the magnetic portion 6 together.

[0086] In the brake device 1 of embodiment 6, the hub 9 has a magnet 10f embedded in the outer peripheral portion of the end of the connecting portion 91 in one direction D1 (specifically, the portion located on the inner peripheral side of the side plate 8). The magnet 10f has an annular shape when viewed in one direction D1. The magnet 10f may be composed of multiple magnetic pieces embedded in the connecting portion 91 at intervals in the circumferential direction. The side plate 8 and the hub 9 are each made of a magnetic material. The magnet 10f generates a magnetic force in a direction that attracts the side plate 8 and the magnetic portion 6 to each other. The brake device 1 of embodiment 6 does not include a spacer 12 (see Figure 3).

[0087] In the brake device 1 of embodiment 6, the magnet 10f can attract the side plate 8 and the magnetic part 6 to each other, thereby sandwiching the friction plate 7 between the side plate 8 and the magnetic part 6 and restricting the rotation of the friction plate 7 and the hub 9.

[0088] (Embodiment 7) Next, the brake device 1 of the seventh embodiment shown in Fig. 11 will be described in detail with reference to the drawings. In the following, the components of the brake device 1 of the seventh embodiment that are common to the first embodiment will be denoted by the same reference numerals in the drawings and detailed description will be omitted, and the components that differ from the first embodiment will be described in detail.

[0089] In the brake device 1 of the seventh embodiment, the pressing member 10 is formed of a spring 10g that is embedded in a part of the hub 9 and presses the friction plate 7 against the side plate 8. The brake device 1 does not include a magnetic portion 6 and a spacer 12 (see FIG. 3).

[0090] A spring 10g is embedded in a surface of the base portion 93 of the hub 9 that faces one side in the direction D1 (more specifically, the side of the side plate 8). The spring 10g biases a portion of the main body 70 of the friction plate 7 that is radially inward of the ring portion 71, thereby pressing the friction plate 7 against the side plate 8.

[0091] In the brake device 1 of the seventh embodiment, the spring 10g can press the friction plate 7 against the side plate 8, thereby restricting the rotation of the friction plate 7 and the hub 9.

[0092] In the brake device 1 of the seventh embodiment, the magnetic portion 6 can be omitted, and therefore the brake device 1 can be easily made smaller in size in one direction D1.

[0093] (Variation) Next, a description will be given of modified examples of the brake device 1 according to the above-described first to seventh embodiments. The modified examples shown below can be combined as appropriate.

[0094] In the brake device 1 of the first embodiment, the magnet 10a is only required to be disposed between the side plate 8 and the magnetic portion 6 and generate a magnetic force in a direction that attracts the side plate 8 and the magnetic portion 6, and does not have to be configured as part of the spacer 12. The brake device 1 does not have to include the spacer 12, and the magnet 10a may be disposed between the side plate 8 and the magnetic portion 6 as a separate member from the spacer 12.

[0095] In the brake device 1 of the second embodiment, the magnet 10b may constitute a part of the magnetic portion 6 and generate a magnetic force in a direction that attracts the side plate 8 to the magnetic portion 6. The magnet 10b may be the entire magnetic portion 6, not just the protruding portion 61 of the magnetic portion 6. Alternatively, only the main body portion 60 of the magnetic portion 6 may be the magnet 10b. Alternatively, the magnet 10b may be provided so as to extend from the protruding portion 61 to the main body portion 60, as in the modified example shown in FIG. 12 . The magnet 10b may be provided on the remaining portion of the magnetic portion 6 excluding both radial ends, or may be provided so as to extend from one radial end to the other radial end of the magnetic portion 6 (i.e., from the inner circumferential end of the main body portion 60 to the outer circumferential end of the protruding portion 61). Alternatively, the magnet 10b may be provided on all of the multiple protruding portions 61. When viewed in one direction D1, two circumferentially adjacent magnets 10b may have a clockwise magnetization direction and the other a counterclockwise magnetization direction. Furthermore, all of the magnets 10b may have a clockwise magnetization direction when viewed in one direction D1, or may have a counterclockwise magnetization direction.

[0096] In the brake device 1 of embodiment 3, the screws 10c may be any screws that fasten the side plate 8 to the magnetic portion 6, and are not limited to the structure and arrangement shown in Fig. 7. The screws 10c may be flat head screws, and may be provided so that the heads of the screws 10c fit within the thickness of the side plate 8. The brake device 1 of embodiment 3 does not need to include the spacer 12.

[0097] In the brake device 1 of the fourth embodiment, the spring 10d is provided on the outside of the side plate 8 in one direction D1 and is not limited to the structure, arrangement, and number shown in Fig. 8 as long as it presses the side plate 8 against the friction plate 7. The spring 10d does not have to be a coil spring, and may be a spring material with another structure such as a leaf spring.

[0098] In the brake device 1 of the fifth embodiment, the spring 10e is not limited to the structure shown in Fig. 9 as long as it is disposed between the side plate 8 and the magnetic portion 6 and biases the side plate 8 and the magnetic portion 6 in a direction that attracts them together. The brake device 1 of the fifth embodiment does not need to include the spacer 12, and the spring 10e may be disposed in the space between the side plate 8 and the magnetic portion 6.

[0099] In the brake device 1 of embodiment 6, the magnet 10f is embedded in a part of the hub 9 and may be embedded in the hub 9 at a position other than the position shown in Figure 10, as long as it generates a magnetic force in a direction that attracts the side plate 8 and the magnetic part 6.

[0100] The brake device 1 of the seventh embodiment is not limited to the structure shown in Fig. 11. The brake device 1 of the seventh embodiment may include a magnetic portion 6.

[0101] Furthermore, the basic structure of the brake device 1 according to the first to seventh embodiments is not limited to the structure shown in FIGS.

[0102] For example, the shape of the pair of tongues 31 is not limited to that shown in Fig. 3 and may be other shapes than arc shapes. Furthermore, the shape of the connecting portion 91 of the hub 9 and the shape of the fitting hole 700 of the friction plate 7 may be other shapes that allow them to fit together.

[0103] (summary) As in the first to sixth embodiments and their modifications described above, the brake device (1) according to the first aspect of the present disclosure has the following configuration.

[0104] That is, a brake device (1) of a first aspect includes a shaft (2) extending in one direction (D1), a wrap spring unit (3), an annular stator (4) surrounding the wrap spring unit (3), and an electromagnetic coil (5) built into the stator (4). The wrap spring unit (3) has a wrap spring (30) wound around the shaft (2) and a pair of magnetic tongues (31) fixed to both ends of the wrap spring (30) in the winding direction. The brake device (1) further includes an annular magnetic portion (6) and an annular friction plate (7) aligned in one direction relative to the stator (4), a side plate (8) capable of sandwiching the friction plate (7) between the magnetic portion (6) and the side plate (8), and a hub (9). The brake device (1) further includes a pressing member (10) that presses the side plate (8) and the magnetic portion (6) against the friction plate (7). The hub (9) has a bearing portion (90) that rotatably supports the shaft (2), a connecting portion (91) that is connected to the friction plate (7) so as not to rotate relative to the shaft (2), and a stopper portion (92) located between the pair of tongues (31). When the electromagnetic coil (5) is energized, the pair of tongues (31) move in a direction that expands the inner diameter of the wrap spring (30) due to the magnetic attraction force of the electromagnetic coil (5), thereby releasing the shaft (2). When the electromagnetic coil (5) is not energized, the pair of tongues (31) move in a direction that narrows the inner diameter of the wrap spring (30) due to the spring force of the wrap spring (30), causing the wrap spring (30) to wrap around and become integrated with the shaft (2). Then, the pair of tongues (31), which rotate integrally with the shaft (2), come into contact with the stopper portion (92), restricting their rotation, thereby braking the shaft (2). The pressing member (10) is disposed outside the stator (4).

[0105] In the brake device (1) of the first aspect having the above configuration, the pressing member (10) is disposed outside the stator (4), making it easy to increase the winding area of ​​the electromagnetic coil (5) in the stator (4) in the radial direction of the shaft (2). Therefore, in the brake device (1) of the first aspect, it is easy to reduce the power consumption required to obtain the magnetic attraction force required to attract the pair of tongues (31). Alternatively, in the brake device (1) of the first aspect, it is easy to increase the winding area of ​​the electromagnetic coil (5) in the stator (4) in the radial direction of the shaft (2), making it easy to reduce the winding area of ​​the electromagnetic coil (5) in one direction (D1). Therefore, in the brake device (1) of the first aspect, it is easy to reduce the size of the electromagnetic coil (5) and the stator (4) in one direction (D1).

[0106] Furthermore, like the above-described first embodiment and its modified example, the brake device (1) of the second aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0107] That is, in the brake device (1) of the second embodiment, the pressing member (10) is arranged between the side plate (8) and the magnetic part (6) and is composed of a magnet (10a) that generates a magnetic force in a direction that attracts the side plate (8) and the magnetic part (6).

[0108] In the brake device (1) of the second aspect having the above configuration, the pressing member (10) consisting of the magnet (10a) is housed between the side plate (8) and the magnetic part (6), so that the brake device (1) can be prevented from becoming larger in one direction (D1).

[0109] Furthermore, like the above-described second embodiment and its modified example, the brake device (1) of the third aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0110] That is, in the brake device (1) of the third aspect, the pressing member (10) is configured with a magnet (10b) that forms part of the magnetic part (6) and generates a magnetic force in a direction that attracts the side plate (8) to the magnetic part (6).

[0111] In the brake device (1) of the third aspect having the above configuration, the pressing member (10) is a magnet (10b) that constitutes part of the magnetic portion (6), so that the brake device (1) can be prevented from increasing in size in one direction (D1).

[0112] Furthermore, like the third embodiment and its modified example, the brake device (1) of the fourth aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0113] That is, in the brake device (1) of the fourth embodiment, the pressing member (10) is composed of a screw (10c) that fastens the side plate (8) to the magnetic portion (6).

[0114] In the brake device (1) of the fourth aspect having the above configuration, the pressing member (10) is the screw (10c) that fastens the side plate (8) to the magnetic portion (6), so that it is possible to prevent the brake device (1) from increasing in size in one direction (D1). In addition, in the brake device (1) of the fourth aspect, the degree of fastening of the screw (10c) is easily changed, and it is easy to adjust the force with which the side plate (8) and the magnetic portion (6) clamp the friction plate (7).

[0115] Furthermore, like the fourth embodiment and its modified example, the brake device (1) of the fifth aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0116] That is, in the brake device (1) of the fifth aspect, the pressing member (10) is provided on the outer side of the side plate (8) in one direction (D1) and is composed of a spring (10d) that presses the side plate (8) against the friction plate (7).

[0117] According to the brake device (1) of the fifth aspect having the above configuration, it is not necessary to change the material or shape of the side plate (8) or the magnetic portion (6) in order to provide the pressing member (10), and therefore it is easy to manufacture.

[0118] Furthermore, like the fifth embodiment and its modified examples described above, the brake device (1) of the sixth aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0119] That is, in the brake device (1) of the sixth aspect, the pressing member (10) is arranged between the side plate (8) and the magnetic part (6) and is composed of a spring (10e) that biases the side plate (8) and the magnetic part (6) in a direction that attracts them together.

[0120] According to the brake device (1) of the sixth aspect having the above configuration, the pressing member (10) consisting of the spring (10e) is housed between the side plate (8) and the magnetic part (6), so that the brake device (1) can be prevented from becoming large in one direction (D1).

[0121] Furthermore, like the sixth embodiment and its modified examples described above, the brake device (1) of the seventh aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0122] That is, in the seventh aspect of the brake device (1), the pressing member (10) is configured with a magnet (10f) embedded in a part of the hub (9) and generating a magnetic force in a direction that attracts the side plate (8) and the magnetic part (6).

[0123] According to the seventh aspect of the brake device (1) having the above configuration, the pressing member (10) made of the magnet (10f) is embedded in a part of the hub (9), so that the brake device (1) can be prevented from becoming large in one direction (D1).

[0124] Furthermore, like the seventh embodiment and its modified example, the brake device (1) of the eighth aspect additionally includes the following configuration.

[0125] That is, the brake device (1) of the eighth aspect includes a shaft (2) extending in one direction, a wrap spring unit (3), an annular stator (4) surrounding the wrap spring unit (3), and an electromagnetic coil (5) built into the stator (4). The wrap spring unit (3) has a wrap spring (30) wound around the shaft (2) and a pair of magnetic tongues (31) fixed to both ends of the wrap spring (30) in the winding direction. The brake device (1) further includes an annular friction plate (7) and side plate (8) aligned in one direction relative to the stator (4), a hub (9), and a pressing member (10) that presses the friction plate (7) against the side plate (8). The hub (9) has a bearing portion (90) that rotatably supports the shaft (2), a connecting portion (91) that is connected to the friction plate (7) so as not to rotate relative to the shaft (2), and a stopper portion (92) located between the pair of tongues (31). When the electromagnetic coil (5) is energized, the pair of tongues (31) move in a direction that expands the inner diameter of the wrap spring (30) due to the magnetic attraction force of the electromagnetic coil (5), thereby releasing the shaft (2). When the electromagnetic coil (5) is not energized, the pair of tongues (31) move in a direction that narrows the inner diameter of the wrap spring (30) due to the spring force of the wrap spring (30), causing the wrap spring (30) to wrap around and become integrated with the shaft (2). Then, the pair of tongues (31), which rotate integrally with the shaft (2), come into contact with the stopper portion (92), restricting their rotation, thereby braking the shaft (2). The pressing member (10) is embedded in a part of the hub (9) and is composed of a spring (10g) that presses the friction plate (7) against the side plate (8).

[0126] According to the brake device (1) of the eighth aspect having the above configuration, the pressing member (10) is disposed on the hub (9) outside the stator (4), which makes it easy to increase the winding area of ​​the electromagnetic coil (5) in the stator (4) in the radial direction of the shaft (2). Therefore, in the brake device (1) of the eighth aspect, it is easy to reduce the power consumption required to generate the magnetic attraction force required to attract the pair of tongues (31). Alternatively, in the brake device (1) of the eighth aspect, the winding area of ​​the electromagnetic coil (5) in the stator (4) can be increased in the radial direction of the shaft (2), which makes it easy to reduce the winding area of ​​the electromagnetic coil (5) in one direction (D1). Therefore, in the brake device (1) of the eighth aspect, it is easy to reduce the size of the electromagnetic coil (5) and the stator (4) in one direction (D1). Furthermore, in the brake device (1) of the eighth aspect, the pressing member (10) made of the spring (10g) is embedded in a part of the hub (9), so that the brake device (1) can be prevented from increasing in size in one direction (D1).

[0127] The present disclosure has been described above based on the embodiments shown in the accompanying drawings, but the present disclosure is not limited to the above embodiments, and appropriate design changes are possible within the intended scope of the present disclosure. [Explanation of symbols]

[0128] 1 Brake device 2 shafts 3 Wrap spring unit 30 Wrap Spring 31 Tongue 4 Stator 5. Electromagnetic coil 6 Magnetic part 7 Friction plate 8 Side Plate 9. Hub 90 Bearing 91 Connecting part 92 Stopper part 10 Pressing member 10a Magnet 10b Magnet 10c screw 10d spring 10e spring 10f Magnet 10g spring D1 One direction

Claims

1. A shaft extending in one direction; a wrap spring unit including a wrap spring wound around the shaft and a pair of magnetic tongues fixed to both ends of the wrap spring in the winding direction; an annular stator surrounding the wrap spring unit; an electromagnetic coil built into the stator; an annular magnetic portion and an annular friction plate arranged in the one direction relative to the stator; a side plate capable of sandwiching the friction plate between itself and the magnetic portion; a hub having a bearing portion for rotatably supporting the shaft, a connecting portion connected to the friction plate so as not to rotate relative to the friction plate, and a stopper portion located between the pair of tongues; a pressing member that presses the side plate and the magnetic portion against the friction plate, When the electromagnetic coil is energized, the pair of tongues move in a direction that expands the inner diameter of the wrap spring due to the magnetic attraction force of the electromagnetic coil, thereby releasing the shaft. When the electromagnetic coil is de-energized, the pair of tongues move in a direction that narrows the inner diameter of the wrap spring due to the spring force of the wrap spring, causing the wrap spring to wrap around the shaft and become one with it, and the pair of tongues, which rotate integrally with the shaft, come into contact with the stopper portion and are restricted from rotating, thereby applying a brake to the shaft, The pressing member is disposed outside the stator. Brake device.

2. The pressing member is disposed between the side plate and the magnetic portion, and is configured by a magnet that generates a magnetic force in a direction that attracts the side plate and the magnetic portion. The braking device according to claim 1 .

3. The pressing member is a magnet that constitutes part of the magnetic portion and generates a magnetic force in a direction that attracts the side plate to the magnetic portion. The braking device according to claim 1 .

4. The pressing member is and a screw for fastening the side plate to the magnetic portion. The braking device according to claim 1 .

5. the pressing member is provided on the outer side of the side plate in the one direction and is configured as a spring that presses the side plate against the friction plate. The braking device according to claim 1 .

6. The pressing member is arranged between the side plate and the magnetic portion and is configured as a spring that biases the side plate and the magnetic portion in a direction that attracts them together. The braking device according to claim 1 .

7. The pressing member is configured by a magnet embedded in a part of the hub and generating a magnetic force in a direction that attracts the side plate and the magnetic portion. The braking device according to claim 1 .

8. A shaft extending in one direction; a wrap spring unit including a wrap spring wound around the shaft and a pair of magnetic tongues fixed to both ends of the wrap spring in the winding direction; an annular stator surrounding the wrap spring unit; an electromagnetic coil built into the stator; an annular friction plate and a side plate arranged in the one direction relative to the stator; a hub having a bearing portion for rotatably supporting the shaft, a connecting portion connected to the friction plate so as not to rotate relative to the friction plate, and a stopper portion located between the pair of tongues; a pressing member that presses the friction plate against the side plate, When the electromagnetic coil is energized, the pair of tongues move in a direction that expands the inner diameter of the wrap spring due to the magnetic attraction force of the electromagnetic coil, thereby releasing the shaft. When the electromagnetic coil is de-energized, the pair of tongues move in a direction that narrows the inner diameter of the wrap spring due to the spring force of the wrap spring, causing the wrap spring to wrap around the shaft and become one with it, and the pair of tongues, which rotate integrally with the shaft, come into contact with the stopper portion and are restricted from rotating, thereby applying a brake to the shaft, The pressing member is formed of a spring that is embedded in a part of the hub and presses the friction plate against the side plate. Brake device.

Images