Brake device

Abstract

To provide a brake device easily thinned and further easily suppressing power consumption.SOLUTION: A brake device 1 includes a shaft 2, a wrap spring unit 5 having a wrap spring 3 and a pair of tongues 4, a stator 6, an electromagnetic coil 7, a magnetic part 8, a magnet 9 and a hub 10. The hub 10 includes: a bearing part 100 by which the shaft 2 is rotatably supported; a connection part 101 unrotatably connected to the magnetic part 8; and a stopper part 102 located between the pair of tongues 4. When power is supplied to the electromagnetic coil 7, the tongues 4 are moved in a direction extending the inner diameter of the wrap spring 3 to release the shaft 2. When power is not supplied to the electromagnetic coil 7, the tongues 4 move to a direction narrowing the inner diameter of the wrap spring 3, the wrap spring 3 is wound around the shaft 2 to be integrated, the pair of tongues 4 which rotate so as to be integrated to the shaft 2 abut to the stopper part 102 to regulate the rotation, and thereby a brake is applied to the shaft 2.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 mounted on the motor shaft so as not to rotate relative to the motor shaft, an armature 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. The side plate is fixed to the stator with bolts that are inserted into the stator up to the outer periphery of the coil.

[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, the negative action brake described in Patent Document 1 has an armature that moves in the axial direction, and requires an internal space for the armature to move. Therefore, the negative action brake described in Patent Document 1 has a problem in that it is difficult to make it thinner in the axial direction.

[0007] Furthermore, in the negative action brake described in Patent Document 1, bolts for fixing the side plate to the stator are inserted into the outer peripheral portion of the coil of the stator, limiting the space available for arranging the coil. As a result, the negative action brake described in Patent Document 1 has the problem that the power consumption required to generate the electromagnetic force required to attract the armature tends to be large.

[0008] In view of the above circumstances, an object of the present disclosure is to provide a brake device that can be easily made thinner and that consumes less power. [Means for solving the problem]

[0009] A brake device according to one aspect of the present disclosure includes a wrap spring unit having a shaft extending in one direction, 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 stator surrounding the wrap spring unit, an electromagnetic coil built into the stator, and an annular magnetic portion aligned in the one direction relative to the stator. The brake device further includes a magnet provided on the stator and magnetically attracting the magnetic portion to the stator, and a hub. The hub has a bearing portion that rotatably supports the shaft, a connecting portion non-rotatably connected to the magnetic portion, and a stopper portion located between the pair of tongues. When the electromagnetic coil is energized, the magnetic attraction force of the electromagnetic coil causes the pair of tongues to move in a direction that expands the inner diameter of the wrap spring, 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 and integrate with the shaft.The pair of tongues, which rotate integrally with the shaft, then come into contact with the stopper portion, restricting their rotation and applying a brake to the shaft. [Effects of the Invention]

[0010] A brake device according to one aspect of the present disclosure can be easily made thinner and consumes less power. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a brake device according to one 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 another exploded perspective view showing the brake device. [Figure 5]FIG. 5 is an exploded perspective view showing a stator and a bracket provided in the brake device. [Figure 6] FIG. 6 is a side view showing a magnet and a stator included in the first modification of the brake device. [Figure 7] FIG. 7 is a side view showing a magnet and a stator included in the second modification of the brake device. [Figure 8] FIG. 8 is a cross-sectional view showing a third modification of the brake device. DETAILED DESCRIPTION OF THE INVENTION

[0012] (One embodiment) 1. Overview A brake device 1 according to one embodiment shown in FIGS. 1 to 4 includes a shaft 2 extending in one direction D1 and a wrap spring unit 5. The wrap spring unit 5 includes a wrap spring 3 wound around the shaft 2 and a pair of magnetic tongues 4 fixed to both ends of the wrap spring 3 in the winding direction. The brake device 1 further includes an annular stator 6 surrounding the wrap spring unit 5, an electromagnetic coil 7 built into the stator 6, and an annular magnetic portion 8 aligned with the stator 6 in the one direction D1. The brake device 1 further includes a magnet 9 provided on the stator 6 for magnetically attracting the magnetic portion 8 to the stator 6, and a hub 10. The hub 10 includes a bearing portion 100 that rotatably supports the shaft 2, a connecting portion 101 non-rotatably connected to the magnetic portion 8, and a stopper portion 102 located between the pair of tongues 4. When the electromagnetic coil 7 is energized, the pair of tongues 4 move in a direction that expands the inner diameter of the wrap spring 3 due to the magnetic attraction force of the electromagnetic coil 7, thereby releasing the shaft 2. When the electromagnetic coil 7 is not energized, the pair of tongues 4 move in a direction that narrows the inner diameter of the wrap spring 3 due to the spring force of the wrap spring 3, causing the wrap spring 3 to wrap around and become one with the shaft 2. Then, the pair of tongues 4, which rotate integrally with the shaft 2, come into contact with the stopper portion 102, restricting the rotation and applying a brake to the shaft 2.

[0013] In one embodiment of the brake device 1 having the above configuration, the wrap spring 3, which moves radially of the shaft 2, can brake and release the shaft 2. Furthermore, in this brake device 1, the magnetic portion 8, which is non-rotatably connected to the hub 10 that stops the rotation of the shaft 2 when the electromagnetic coil 7 is de-energized, is attracted to the stator 6 by the magnetic force of the magnet 9 and does not move in the axial direction of the shaft 2. Therefore, unlike conventional brake devices, the brake device 1 does not require a component that moves in the axial direction of the shaft 2, and does not require internal space for such movement, making it easy to achieve a thin design. Furthermore, because the magnetic portion 8 is attracted to the stator 6 by the magnet 9, the brake device 1 does not require a fastener to secure the magnetic portion 8 to the stator 6, eliminating the need for a fastener that would limit the space available for the electromagnetic coil 7. Therefore, in this brake device 1, the winding area of ​​the electromagnetic coil 7 can be easily expanded radially of the shaft 2, making it easy to reduce power consumption required to generate the electromagnetic force required to attract the pair of tongues 4. Therefore, the brake device 1 is easy to achieve a thin design and consumes less power.

[0014] 2.Details Next, the brake device 1 of one embodiment shown in Figures 1 to 5 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] 1 to 4, the brake device 1 includes a shaft 2, a wrap spring unit 5 having a wrap spring 3 and a pair of tongues 4, a stator 6, an electromagnetic coil 7, a magnetic portion 8, a magnet 9, and a hub 10. The brake device 1 further includes a bracket 11 and a fixture 12, as shown in FIG.

[0016] 2-1. Shaft 1 to 4, 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 5 is wound around the shaft 2, and the shaft 2 is supported by a hub 10 so as to be rotatable or non-rotatable.

[0017] 2-2. Wrap spring unit As shown in FIG. 3, the wrap spring unit 5 includes a wrap spring 3 wound around a shaft 2, and a pair of tongues 4 fixed to both ends of the wrap spring 3 in the winding direction.

[0018] The wrap spring unit 5 is configured so that, when the electromagnetic coil 7 is energized, the pair of tongues 4 move in a direction that expands the inner diameter of the wrap spring 3 due to the magnetic attraction force of the electromagnetic coil 7, thereby releasing the shaft 2. Furthermore, the wrap spring unit 5 is configured so that, when the electromagnetic coil 7 is not energized, the pair of tongues 4 move in a direction that narrows the inner diameter of the wrap spring 3 due to the spring force of the wrap spring 3, thereby causing the wrap spring 3 to wrap around the shaft 2.

[0019] In this embodiment, the wrap spring 3 has a spiral main body 30 wound around the shaft 2, and a pair of arm portions 31 extending linearly from one end and the other end of the main body 30 in the winding direction and fixed to a pair of tongues 4.

[0020] The wrap spring 3 has a rectangular cross section perpendicular to the winding direction. The main body 30 is a cylindrical coil spring. The main body 30 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 31 extend linearly from one end and the other end of the main body portion 30 in the winding direction so as to be parallel to the tangent lines at these ends. The pair of arm portions 31 are positioned at a distance in one direction D1 (i.e., the axial direction of the shaft 2). The pair of arm portions 31 protrude to the same side from the main body portion 30 when viewed in the one direction D1. When viewed in the one direction D1, the pair of arm portions 31 extend linearly so that the distance between them becomes narrower toward the tip end.

[0022] Each of the pair of tongues 4 is made of a magnetic material. Each of the pair of tongues 4 has an arc shape that follows the inner circumferential surface of the stator 6. In this embodiment, the pair of tongues 4 have the same size and shape and are provided point symmetrically. Each of the pair of tongues 4 has an arm portion 31 fixed to the end on the same side.

[0023] Each of the pair of tongues 4 has a length in one direction D1 that is approximately the same as that of the wrap spring 3. One of the tongues 4 has an arm portion 31 fixed to one end in the direction D1, and the other tongue 4 has an arm portion 31 fixed to the other end in the direction D1.

[0024] In this embodiment, when the electromagnetic coil 7 is energized, the magnetic attraction force of the electromagnetic coil 7 causes the pair of tongues 4 to move radially outward from the shaft 2 so that the gap between the tip ends of the pair of arm portions 31 increases, thereby increasing the inner diameter of the wrap spring 3. When the electromagnetic coil 7 is not energized, the magnetic attraction force of the electromagnetic coil 7 no longer acts on the pair of tongues 4, and the spring force of the wrap spring 3 causes the pair of tongues 4 to move radially inward from the shaft 2 so that the gap between the tip ends of the pair of arm portions 31 decreases. This reduces the inner diameter of the wrap spring 3, causing the wrap spring 3 to wrap around the shaft 2. When the wrap spring 3 is wound around the shaft 2, the wrap spring unit 5 rotates integrally with the shaft 2.

[0025] 2-3. Stator and electromagnetic coil The stator 6 shown in Figs. 1 to 4 is an annular member that surrounds the wrap spring unit 5. The stator 6 is made of a magnetic material. An electromagnetic coil 7 is built into the stator 6. The stator 6 is further provided with a magnet 9.

[0026] As shown in Figures 3 and 4, in this embodiment, the stator 6 has a first part 6a and a second part 6b that sandwich the electromagnetic coil 7 in one direction D1, and a fastener 6c such as a screw that fastens the first part 6a and the second part 6b together.

[0027] The first portion 6a has a cylindrical outer cylinder portion 60, a cylindrical inner cylinder portion 61, and an annular support portion 62 that connects one end of the outer cylinder portion 60 and one end of the inner cylinder portion 61 in one direction D1. The inner cylinder portion 61 is concentrically disposed inside the outer cylinder portion 60. The electromagnetic coil 7 is housed in a space surrounded by the outer cylinder portion 60, the inner cylinder portion 61, and the support portion 62 (see FIG. 2). An extension portion 600 is provided at a portion (three portions in this embodiment) in the circumferential direction of the outer cylinder portion 60, extending to one side in one direction D1 (more specifically, the side opposite to the support portion 62). The extension portion 600 is provided with an insertion hole 601 through which the fixing device 6c is inserted.

[0028] The surface of the support portion 62 opposite to the electromagnetic coil 7 constitutes a support surface 620 that supports the magnet 9. The support surface 620 is provided with a recess 621 in which the magnet 9 is housed. In this embodiment, the support surface 620 is provided with a plurality of recesses 621. Each of the plurality of recesses 621 is a rectangular recess when viewed in one direction D1. The plurality of recesses 621 are positioned at intervals in the circumferential direction of the support portion 62. A through-hole 622 that penetrates the support portion 62 is provided in the bottom of each of the plurality of recesses 621.

[0029] The second portion 6b has an annular base plate 63 when viewed in the direction D1, a cylindrical tube portion 64 protruding from the inner periphery of the base plate 63 to one side in the direction D1, and a plurality of fitting protrusions 65 protruding from the base plate 63 to the other side in the direction D1. As shown in Fig. 2, the position of the tube portion 64 in the radial direction of the shaft 2 is the same as that of the inner tube portion 61 of the first portion 6a.

[0030] As shown in FIG. 3, the multiple fitting protrusions 65 have the same shape. In this embodiment, each of the multiple fitting protrusions 65 has an arc shape when viewed in the direction D1. Each of the multiple fitting protrusions 65 is provided with a fastening hole 650 to which a fixture 12 (see FIG. 5) that fixes the bracket 11 to the stator 6 is fastened. The fastening hole 650 is open only on one side in the direction D1. As shown in FIG. 2, the fastening hole 650 is provided with a length that allows it to fit within the fitting protrusion 65, and is not provided in the base plate 63.

[0031] 3 and 4, a plurality of (three in this embodiment) fastening holes 630 to which fasteners 6c are fastened are provided on the outer peripheral surface of the base plate 63. As shown in Fig. 2, each of the plurality of fastening holes 630 is provided so as to span the base plate 63 and one of the fitting protrusions 65. The plurality of fastening holes 630 are positioned offset from the plurality of fastening holes 650 in the circumferential direction of the second portion 6b and do not interfere with each other.

[0032] The electromagnetic coil 7 is disposed in a region surrounded by the base plate 63 and the cylindrical portion 64 of the second portion 6b, and the support portion 62, the outer cylindrical portion 60, and the inner cylindrical portion 61 of the first portion 6a.

[0033] 3 and 4, the electromagnetic coil 7 is provided in an annular shape when viewed in one direction D1. The inner circumferential surface and both sides of the electromagnetic coil 7 in the one direction D1 are covered with an insulating member. When energized, the electromagnetic coil 7 generates a magnetic attraction force in a direction that attracts the pair of tongues 4 (i.e., radially outward from the shaft 2).

[0034] 2-4.Magnets 4 is provided on the stator 6 and attracts the magnetic portion 8 to the stator 6 by magnetic force. In this embodiment, the magnet 9 is a permanent magnet. Note that the magnet 9 may be a magnetic body that is magnetized by the magnetic flux generated by the electromagnetic coil 7.

[0035] In this embodiment, the magnet 9 is made up of a plurality of magnet pieces 90 housed in each of a plurality of recesses 621. The number of the recesses 621 and the number of the magnet pieces 90 are the same.

[0036] Each of the magnet pieces 90 has a rectangular plate shape when viewed in the direction D1. The magnet pieces 90 are arranged in an annular shape at intervals in the circumferential direction when viewed in the direction D1. Each of the magnet pieces 90 is fitted into a corresponding one of the recesses 621.

[0037] As shown in Figure 2, each of the multiple magnet pieces 90 is configured so that when housed in a corresponding recess 621, the surface of the magnet piece 90 facing one side in one direction D1 is flush with the surface surrounding the recess 621 on the support surface 620.

[0038] 2-5.Magnetic part 1 and 2, the magnetic part 8 is an annular member aligned in one direction D1 relative to the stator 6. The magnetic part 8 is attracted to the stator 6 by the magnetic force of the magnet 9. The magnetic part 8 is attracted to the stator 6 so as not to move in the rotation direction of the shaft 2. The magnetic part 8 is magnetic.

[0039] In this embodiment, the magnetic part 8 is a plate-like magnetic member 81 having a fitting hole 80 into which the connecting part 101 of the hub 10 fits.

[0040] 3 and 4, the fitting hole 80 has a rectangular shape with four chamfered corners when viewed in one direction D1. The outer circumferential surface of the magnetic member 81 has the same shape as the outer circumferential surface of the first portion 6a of the stator 6, and in this embodiment, is circular.

[0041] Hub The hub 10 shown in FIGS. 2 to 4 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.

[0042] The hub 10 has a bearing portion 100 that rotatably supports the shaft 2, a connecting portion 101 that is non-rotatably connected to the magnetic portion 8, and a stopper portion 102 that is located between the pair of tongues 4.

[0043] The hub 10 further has a base portion 103 that is arranged inside the inner cylindrical portion 61 of the first part 6a of the stator 6 and is annular when viewed in one direction D1, and a guide portion 104 that is arc-shaped when viewed in one direction D1 and guides the movement of the pair of tongues 4.

[0044] The base portion 103 has a thickness in one direction D1. The bearing portion 100 is provided inside the annular base portion 103. The bearing portion 100 is a ball bearing.

[0045] The connecting portion 101 protrudes from the base portion 103 toward one side in the direction D1. The connecting portion 101 has a shape that fits non-rotatably into the fitting hole 80 of the magnetic portion 8, and in this embodiment, is octagonal. The connecting portion 101 fits into the fitting hole 80 with four edge portions of the connecting portion 101 abutting against the inner circumferential surface of the rectangular fitting hole 80.

[0046] A stopper portion 102 and a guide portion 104 protrude from the base portion 103 toward the other side in the direction D1. The stopper portion 102 is provided on a portion of the circumferential direction of the base portion 103. In this embodiment, the stopper portion 102 is a block having a rectangular cross section perpendicular to the direction D1.

[0047] The guide portion 104 is provided on a part of the circumferential direction of the inner periphery of the base portion 103. The central portion of the guide portion 104 in the circumferential direction is provided integrally with the stopper portion .

[0048] The hub 10 is arranged so that the connecting portion 101 fits into the fitting hole 80 of the magnetic portion 8, and the base portion 103, the stopper portion 102, and the guide portion 104 are located inside the stator 6. The shaft 2 is rotatably supported by the bearing portion 100.

[0049] The connecting portion 101 of the hub 10 is fitted into the fitting hole 80 of the magnetic portion 8, so that the hub 10 is unable to rotate relative to the magnetic portion 8. Here, the magnetic portion 8 is attracted to the stator 6 by the attractive force of the magnet 9, and its rotation is restricted. Therefore, the hub 10 is attached to the stator 6 in a state where its rotation is restricted.

[0050] 1, the hub 10 is disposed so that the stopper portion 102 is located between the pair of tongues 4 of the wrap spring unit 5. A guide portion 104 is disposed between the main body portion 30 of the wrap spring 3 and the pair of tongues 4.

[0051] 2-7.Brackets and Fixtures 5 is attached to the stator 6 on the side opposite to the magnetic portion 8, and covers the wrap spring unit 5 (see FIG. 1, etc.). A fixing tool 12 fixes the bracket 11 to the stator 6.

[0052] The bracket 11 has a mating recess 110 into which the mating protrusion 65 fits. In this embodiment, the bracket 11 is provided with a plurality of (more specifically, three) mating recesses 110. Each of the plurality of mating recesses 110 is an arc-shaped recess when viewed in the direction D1. A through hole 111 that penetrates the bracket 11 in the direction D1 is provided at the bottom of each of the plurality of mating recesses 110. The arrangement of the through holes 111 in the mating recess 110 is the same as the arrangement of the fastening holes 650 in the mating protrusion 65. The fixing device 12 is passed through the through hole 111. An insertion hole 112 through which the shaft 2 is inserted is provided at the center of the bracket 11.

[0053] By fixing the bracket 11 to the stator 6 with the fixture 12, the wrap spring unit 5 arranged in the stator 6 is covered and hidden from one side in the one direction D1.

[0054] 3. Brake device operation Next, the operation of the above-mentioned brake device 1 will be described.

[0055] When the electromagnetic coil 7 starts to be energized, the magnetic attraction force of the electromagnetic coil 7 acts on the pair of tongues 4, causing the pair of tongues 4 to move radially outward (that is, radially outward from the shaft 2).

[0056] As a result, the pair of arms 31 of the wrap spring 3 are displaced in a direction that widens the gap between their tip ends, the inner diameter of the main body 30 of the wrap spring 3 widens, and a gap is formed between the main body 30 and the shaft 2. This releases the wrap spring unit 5 from its pressurized state on the shaft 2, and the brake on the shaft 2 is released.

[0057] When the electromagnetic coil 7 is de-energized, the magnetic attraction force of the electromagnetic coil 7 against the pair of tongues 4 ceases. Then, due to the spring force (more specifically, the restoring force) of the wrap spring 3, the pair of arms 31 of the wrap spring 3 are displaced in a direction narrowing the gap between their tips, narrowing the inner diameter of the main body 30, and the main body 30 is wrapped around and pressed against the shaft 2. At this time, the pair of tongues 4 are in contact with the stopper portion 102 of the hub 10 or positioned with a small gap therebetween. In this state, if the shaft 2 with the wrap spring unit 5 wrapped around it attempts to rotate, one of the pair of tongues 4 will hit the stopper portion 102. Here, because the rotation of the hub 10, which includes the stopper portion 102, is restricted relative to the stator 6, the rotation of the shaft 2 is restricted by the hub 10. As a result, a brake is applied to the shaft 2 when the electromagnetic coil 7 is de-energized.

[0058] 4. Effects In the brake device 1 of the present embodiment described above, the mechanism that applies the brake to the shaft 2 when the electromagnetic coil 7 is de-energized is configured with the wrap spring unit 5 that moves around the shaft 2 in the radial direction of the shaft 2. The hub 10 and magnetic portion 8 that restrict the rotation of the wrap spring unit 5 wrapped around the shaft 2 are provided so as not to move in the axial direction of the shaft 2 (i.e., in one direction D1).

[0059] Therefore, the brake device 1 of this embodiment does not have any components that move in the axial direction of the shaft 2 as in the conventional example, and does not require any internal space for such movement, making it easy to make the device thinner in one direction D1.

[0060] Furthermore, in the brake device 1 of this embodiment, the magnetic part 8 is attracted to the stator 6 by the magnetic force of the magnet 9, so there is no need for a fastener such as a screw to fix the magnetic part 8 to the stator 6, and the stator 6 does not require an insertion space for this fastener to be inserted.

[0061] Therefore, in the brake device 1 of this embodiment, the winding area of ​​the electromagnetic coil 7 in the stator 6 can be increased, and power consumption for obtaining the electromagnetic force required to attract the pair of tongues 4 can be easily reduced.

[0062] Furthermore, in the brake device 1 of this embodiment, the magnet 9 that attracts the magnetic portion 8 to the stator 6 is composed of a plurality of magnet pieces 90 that are spaced apart in the rotational direction of the shaft 2, which makes it easy to reduce the arrangement space for the magnet 9 in one direction D1. Therefore, in this respect as well, it is easy to make the brake device 1 thinner in one direction D1.

[0063] Furthermore, in the brake device 1 of this embodiment, the stator 6 and bracket 11 are attached by fitting the mating convex portion 65 into the mating concave portion 110 and by fixing with the fixing device 12, which makes it possible to reduce the length of the fixing device 12 compared to when fixing is performed only with the fixing device 12. Therefore, in the brake device 1 of this embodiment, it is easy to expand the installation space for the electromagnetic coil 7 inside the stator 6.

[0064] Furthermore, in the brake device 1 of this embodiment, when the electromagnetic coil 7 is energized, the number of contact points between the wrap spring unit 5 and the shaft 2 can be reduced, which makes it easier to reduce mechanical loss.

[0065] 5. Variations Next, a description will be given of modified examples of the above-described brake device 1. The following modified examples can be combined as appropriate.

[0066] The magnet 9 does not have to be configured with a plurality of rectangular plate-shaped magnet pieces 90 as shown in FIGS.

[0067] The magnet 9 may be ring-shaped along the circumferential direction of the annular stator 6, as in Modification 1 of the brake device 1 shown in Fig. 6. In this case, the recess 621 of the stator 6 is provided in a ring shape when viewed in one direction D1. In this modification, it is easy to increase the area of ​​the surface of the magnet 9 facing the magnetic portion 8, and therefore it is easy to make the magnet 9 thinner in one direction D1, and it is easy to make the brake device 1 thinner in one direction D1.

[0068] Furthermore, the magnet 9 may be composed of a plurality of arc-shaped magnet pieces 91 spaced apart in the circumferential direction of the annular stator 6, as in Modification 2 of the brake device 1 shown in Figure 7. In this case, the recess 621 of the stator 6 is composed of a plurality of arc-shaped recesses spaced apart in the circumferential direction of the stator 6, as viewed in one direction D1. In this modification, it is easy to increase the area of ​​the surface of the magnet 9 facing the magnetic portion 8, and it is easy to thin the magnet 9 in one direction D1, so it is easy to thin the magnet 9 in one direction D1, and it is easy to thin the brake device 1 in one direction D1.

[0069] Furthermore, the magnetic portion 8 only needs to have magnetic properties and does not have to be composed of a single plate-shaped magnetic member 81. For example, as in Modification 3 of the brake device 1 shown in FIG. 8, the magnetic portion 8 may be composed of a single plate-shaped magnetic member 81 and a plate-shaped cover material 83 attached to the outside of the magnetic member 81 in one direction D1. The cover material 83 is a member that has weaker magnetic properties than the magnetic member 81 or does not have magnetic properties. The cover material 83 is attached to the magnetic member 81 by, for example, adhesion.

[0070] Furthermore, the brake device 1 is not limited to the structure shown in FIGS.

[0071] The shape of the pair of tongues 4 is not limited to that shown in Figures 3 and 4. The magnets 9 may be built into the stator 6, and may not be exposed from the support surface 620 of the stator 6.

[0072] Furthermore, the shape of the connecting portion 101 of the hub 10 and the shape of the fitting hole 80 of the magnetic portion 8 may be other shapes that allow them to fit together.

[0073] Furthermore, the electromagnetic coil 7 is not limited to the structure shown in FIG. 3, as long as it is configured to attract the pair of tongues 4 in the direction in which the inner diameter of the wrap spring 3 expands when energized.

[0074] Furthermore, bracket 11 is not limited to the structure shown in FIG. 5 as long as it can be attached to stator 6.

[0075] (summary) As in the embodiment and its modified example described above, the brake device (1) according to the first aspect of the present disclosure has the following configuration.

[0076] That is, a brake device (1) of a first aspect includes a shaft (2) extending in one direction (D1) and a wrap spring unit (5). The wrap spring unit (5) has a wrap spring (3) wound around the shaft (2) and a pair of magnetic tongues (4) fixed to both ends of the wrap spring (3) in the winding direction. The brake device (1) further includes an annular stator (6) surrounding the wrap spring unit (5), an electromagnetic coil (7) built into the stator (6), and an annular magnetic portion (8) aligned in one direction (D1) relative to the stator (6). The brake device (1) further includes a magnet (9) provided on the stator (6) for magnetically attracting the magnetic portion (8) to the stator (6), and a hub (10). The hub (10) has a bearing portion (100) that rotatably supports the shaft (2), a connecting portion (101) that is non-rotatably connected to the magnetic portion (8), and a stopper portion (102) located between the pair of tongues (4). When the electromagnetic coil (7) is energized, the pair of tongues (4) move in a direction that expands the inner diameter of the wrap spring (3) due to the magnetic attraction force of the electromagnetic coil (7), thereby releasing the shaft (2). When the electromagnetic coil (7) is not energized, the pair of tongues (4) move in a direction that narrows the inner diameter of the wrap spring (3) due to the spring force of the wrap spring (3), causing the wrap spring (3) to wrap around the shaft (2) and become one with it. Then, the pair of tongues (4), which rotate integrally with the shaft (2), come into contact with the stopper portion (102), restricting their rotation, thereby braking the shaft (2).

[0077] In the brake device (1) of the first aspect having the above configuration, the wrap spring (3) that moves radially of the shaft (2) can brake and release the shaft (2). Furthermore, in this brake device (1), the magnetic portion (8) to which the hub (10) that stops the rotation of the shaft (2) when the electromagnetic coil (7) is de-energized is non-rotatably connected. The magnetic portion (8) is attracted to the stator (6) by the magnetic force of the magnet (9) and does not move in the axial direction of the shaft (2). Therefore, unlike conventional brake devices, the brake device (1) does not require a component that moves in the axial direction of the shaft (2), and does not require internal space for such movement, making it easy to achieve a slim design. Furthermore, because the magnetic portion (8) is attracted to the stator (6) by the magnet (9), the brake device (1) does not require a fastener to secure the magnetic portion (8) to the stator (6). Therefore, it is possible to prevent a fastener from being placed in the space around the electromagnetic coil (7) of the stator (6), which would limit the space available for the electromagnetic coil (7). This makes it easy to expand the winding area of ​​the electromagnetic coil 7 in the radial direction of the shaft 2, and to reduce the power consumption required to generate the electromagnetic force required to attract the pair of tongues 4. Therefore, the brake device 1 can be easily made thinner and consumes less power.

[0078] As in the embodiment and its modification described above, the brake device (1) of the second aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0079] That is, in the brake device (1) of the second embodiment, the magnetic part (8) is a plate-shaped magnetic member (81) having a fitting hole (80) into which the connecting part (101) of the hub (10) fits non-rotatably.

[0080] In the brake device (1) of the second aspect having the above configuration, the magnetic portion (8) can be easily made thin, and therefore the brake device (1) can be easily made thin.

[0081] As in the embodiment and its modification described above, the brake device (1) of the third aspect additionally includes the following configuration in addition to the configuration of the first or second aspect.

[0082] That is, the brake device (1) of the third aspect further includes a bracket (11) attached to the stator (6) on the side opposite the magnetic portion (8) and covering the wrap spring unit (5), and a fastener (12) that fastens the bracket (11) to the stator (6). The stator (6) has a mating protrusion (65) that protrudes toward the bracket (11). The bracket (11) has a mating recess (110) into which the mating protrusion (65) fits. A fastening hole (650) into which the fastener (12) is fastened is provided so as to fit within the mating protrusion (65).

[0083] In the brake device (1) of the third aspect having the above configuration, the bracket (11) and the stator (6) can be fixed by fitting the fitting protrusion (65) into the fitting recess (110) and by fixing with the fixture (12), thereby reducing the length of the fixture (12). In the brake device (1) of the third aspect, the fixture (12) can be housed within the fitting protrusion (65), which prevents the space inside the stator (6) from being narrowed by the fixture (12), making it easier to expand the winding area of ​​the electromagnetic coil (7) and reduce power consumption.

[0084] As in the embodiment and its modified example described above, the brake device (1) of the fourth aspect additionally includes the following configuration in addition to the configuration of any one of the first to third aspects.

[0085] That is, in the brake device (1) of the fourth embodiment, the magnet (9) has a ring shape along the circumferential direction of the annular stator (6).

[0086] According to the brake device (1) of the fourth aspect having the above configuration, it is easy to increase the surface area of ​​the face of the magnet (9) facing the magnetic portion (8), and therefore it is easy to reduce the thickness of the magnet (9) in one direction (D1) to obtain the magnetic force necessary to attract the magnetic portion (8) to the stator (6). As a result, the brake device (1) of the fourth aspect can be easily made thinner in one direction (D1).

[0087] As in the embodiment and its modified example described above, the brake device (1) of the fifth aspect additionally includes the following configuration in addition to the configuration of any one of the first to third aspects.

[0088] That is, in the brake device (1) of the fifth aspect, the magnet (9) is composed of a plurality of arc-shaped magnet pieces (91) arranged at intervals in the circumferential direction of the annular stator (6).

[0089] According to the brake device (1) of the fifth aspect having the above configuration, it is easy to increase the surface area of ​​the face of the magnet (9) facing the magnetic portion (8), and therefore it is easy to reduce the thickness of the magnet (9) in one direction (D1) to obtain the magnetic force necessary to attract the magnetic portion (8) to the stator (6). As a result, the brake device (1) of the fifth aspect can be easily made thinner in one direction (D1).

[0090] 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]

[0091] 1 Brake device 2 shafts 3 Wrap Spring 4 Tongue 5 Wrap spring unit 6 Stator 65 mating protrusion 650 fastening holes 7. Electromagnetic Coil 8 Magnetic part 80 fitting hole 81 Magnetic components 9. Magnet 91 Magnet piece 10. Hub 100 Bearing section 101 Connection part 102 Stopper part 11 Bracket 110 Fitting recess 12 Fixtures

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 aligned in the one direction relative to the stator; a magnet provided in the stator and configured to attract the magnetic portion to the stator by magnetic force; a hub having a bearing portion for rotatably supporting the shaft, a connecting portion non-rotatably connected to the magnetic portion, and a stopper portion located between the pair of tongues; Equipped with 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, 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. Brake device.

2. the magnetic portion is a plate-shaped magnetic member having a fitting hole into which the connecting portion of the hub is fitted so as not to rotate, The braking device according to claim 1 .

3. a bracket attached to the stator on the opposite side of the magnetic portion to cover the wrap spring unit; a fastener for fastening the bracket to the stator, the stator has a fitting protrusion that protrudes toward the bracket, the bracket has a fitting recess into which the fitting protrusion fits, The fitting protrusion has a fastening hole to which the fixing tool is fastened, the fastening hole being fitted within the fitting protrusion.

3. A brake device according to claim 1 or 2.

4. The magnet has a ring shape that extends along the circumferential direction of the annular stator.

3. A brake device according to claim 1 or 2.

5. The magnet is composed of a plurality of arc-shaped magnet pieces arranged at intervals in the circumferential direction of the annular stator.

3. A brake device according to claim 1 or 2.

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