Electromagnetic brake device

Abstract

To provide an electromagnetic brake device which can manually release a brake state regardless of whether or not a space is limited in an axial direction of the electromagnetic brake device.SOLUTION: An electromagnetic brake device 10 has: a brake stator 31; a rotary shaft 15; a brake plate 35; a brake armature 32; a suction mechanism which is energized to suction the brake armature 32; a fixed plate 33 which sandwiches and presses the brake plate 35 with the brake armature 32 in a brake state; and a forcing release mechanism 50 which forcibly releases the brake state. The forcing release mechanism 50 has: a ring member which is provided at an outer periphery part of the brake stator 31 and may be displaced along an axial direction of the rotary shaft 15; and a releasing piece 52 which is provided at the ring member 51 and inserted into a space between the fixed plate 33 and the brake armature 32. The outer periphery part has a male screw part 40. An inner periphery part of the ring member 51 has a female screw part 53 which threadedly engages with the male screw part 40.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to an electromagnetic brake device.

Background Art

[0002] As a prior art of an electromagnetic brake device, for example, a non-excitation operation type electromagnetic brake equipped with a manual release device disclosed in Patent Document 1 is known. In the non-excitation operation type electromagnetic brake disclosed in Patent Document 1, a manual release device is provided. The manual release device is composed of a release cam, a manual release arm, an arm holding fitting, and an arm stopper. The release cam moves the armature against the spring force of the brake spring and separates it from the brake lining. The manual release arm rotates the release cam. The arm holding fitting holds the manual release arm at the brake operating position. The arm stopper restricts the rotation range of the manual release arm at the brake release position.

[0003] According to the non-excitation operation type electromagnetic brake disclosed in Patent Document 1, the position of the manual release arm during brake operation and brake release is clear, and the manual release operation is simple and reliable.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the electromagnetic brake device disclosed in Patent Document 1, when the manual release arm is in the brake release position by operation, the tip of the manual release arm is axially separated from the end of the electromagnetic brake device. That is, in this type of electromagnetic brake device, there is a problem that a space for the tip of the manual release arm to rotate is required in the axial direction of the electromagnetic brake device. Therefore, for example, when the space for the manual release arm to rotate in the axial direction of the electromagnetic brake device is restricted, such as when a motor with an electromagnetic brake device is mounted between the suspensions of an industrial vehicle, it cannot be adopted.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide an electromagnetic brake device capable of manually releasing the braking state regardless of the presence or absence of space constraints in the axial direction of the electromagnetic brake device.

Means for Solving the Problems

[0007] In order to solve the above problems, the present invention includes a brake stator, a rotating shaft rotatable with respect to the brake stator, a brake plate fixed to the rotating shaft, a brake armature interposed between the brake stator and the brake plate, an adsorption mechanism for adsorbing the brake armature to the brake stator by energization, a fixing plate for sandwiching the brake plate together with the brake armature in a braking state, a biasing member for biasing the brake armature in a direction away from the brake stator, and a forced release mechanism for separating the brake armature from the brake plate when the adsorption mechanism is inoperative and forcibly releasing the braking state. In the electromagnetic brake device, the forced release mechanism includes a ring member provided on an outer peripheral portion of the brake stator or the fixing plate and displaceable along the axial center direction of the rotating shaft, and a release piece provided on the ring member and inserted between the fixing plate and the brake armature. The outer peripheral portion has a male screw portion, and the inner peripheral portion of the ring member has a female screw portion that engages with the male screw portion.

[0008] In the present invention, the ring member is provided on the outer peripheral portion of the brake stator or the fixed plate, and the female screw portion on the inner peripheral portion of the ring member is screwed with the male screw portion on the outer peripheral portion of the brake stator or the fixed plate. Therefore, when the ring member is rotated in the circumferential direction, the ring member is displaced in the axial direction with respect to the brake stator or the fixed plate. Accordingly, even when the brake is actuated in the non-energized state, the release piece abuts against the brake armature due to the displacement of the ring member, and the brake armature can be separated from the brake plate. According to the present invention, it is possible to manually release the braking state regardless of the presence or absence of the axial space of the electromagnetic brake device.

[0009] Further, in the above electromagnetic brake device, the brake stator has a plurality of bolts arranged in the circumferential direction for fixing the fixed plate to the brake stator, and the release pieces are provided in a plurality in the circumferential direction in the ring member and are arranged so as not to interfere with the plurality of bolts. In this case, since a plurality of release pieces are provided in the circumferential direction of the ring member, when the release pieces separate the brake armature from the brake plate during brake operation, it is possible to hardly cause uneven load on the brake armature. Further, even when the ring member is rotated, a non-braking state can be realized without causing the release pieces to interfere with the bolts.

[0010] Further, in the above electromagnetic brake device, the release piece may be configured to be continuously formed over the circumferential direction of the ring member. In this case, since the release piece is continuously formed over the circumferential direction of the ring member, it is possible to suppress uneven load on the brake armature due to the contact of the release piece.

[0011] Further, in the above electromagnetic brake device, the release piece may be formed of a non-magnetic material. In this case, since the release piece is formed of a non-magnetic material, the release piece is not magnetized, and the brake armature is not attracted to the brake plate due to the magnetization of the release piece.

[0012] Further, in the electromagnetic brake device described above, the ring member may be configured to cover the outer periphery of the brake plate. In this case, since the ring member covers the outer periphery of the brake plate, it is possible to prevent foreign matter from entering the brake plate from the periphery of the electromagnetic brake device.

Effect of the Invention

[0013] According to the present invention, it is possible to provide an electromagnetic brake device that can manually release the braking state regardless of the presence or absence of space constraints in the axial direction of the electromagnetic brake device.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0015] (First Embodiment) Hereinafter, the electromagnetic brake device according to the first embodiment will be described with reference to the drawings. The electromagnetic brake device of this embodiment is a non-excitation braking type electromagnetic brake device that becomes a braking state in a non-excited state. Further, the electromagnetic brake device of this embodiment is an electromagnetic brake device provided in a traveling electric motor mounted on a vehicle, and the vehicle is a forklift as an industrial vehicle. The traveling electric motor is mounted, for example, with a motor with an electromagnetic brake device between the suspensions of the industrial vehicle.

[0016] As shown in FIG. 1, the electromagnetic brake device 10 of this embodiment is provided in the electric motor 11. First, the electric motor 11 will be described. The electric motor 11 includes a rotor 12 and a stator 13. The rotor 12 has a rotor core 14 and a rotating shaft 15 that is fixed through the rotor core 14. The rotating shaft 15 protrudes from both ends of the rotor 12. The stator 13 includes a cylindrical stator core 16 and a stator coil 17. Coil ends 18 of the stator coil 17 are formed at both ends of the stator core 16. In FIG. 1, the coil end 18 at one end is not shown, and only the coil end 18 at the other end is shown.

[0017] The electric motor 11 includes an output side bracket 19 attached to one end of the stator 13 and a brake side bracket 21 on the electromagnetic brake device 10 side attached to the other end of the stator 13. The output side bracket 19 rotatably supports one end of the rotating shaft 15 via a bearing (not shown). The brake side bracket 21 rotatably supports the other end of the rotating shaft 15 via a bearing 22. The output side bracket 19 and the brake side bracket 21 are connected by a through bolt (not shown). A part of the rotating shaft 15 protrudes from the output side bracket 19 as an output shaft 23. Further, an electromagnetic brake device 10 is attached to the other end of the brake side bracket 21. Details of the electromagnetic brake device 10 will be described later.

[0018] The brake-side bracket 21 is provided with a terminal block 24. A lead wire 25 is drawn out from the other coil end 18 of the stator coil 17, and the drawn lead wire 25 is drawn into the terminal block 24. The terminal block 24 has a terminal portion (not shown) that is connected to the lead wire 25 and can be connected to external wiring for connecting to an external device (for example, an inverter). The lead wire 25 is wiring for supplying power to the electric motor 11.

[0019] Next, an electromagnetic brake device 10 that can brake the rotation of the rotor 12 will be described. As shown in FIG. 2, the electromagnetic brake device 10 includes a brake stator 31, a brake armature 32, a brake hub 34, a brake plate 35, and a fixing plate 36.

[0020] The brake stator 31 has an annular stator main body portion 37. The stator main body portion 37 is provided with a through hole 38 in the center for accommodating the other end of the rotating shaft 15 and a part of the brake hub 34. An annular electromagnetic coil 39 as an attracting mechanism is built into the stator main body portion 37. The electromagnetic coil 39 energizes the brake stator 31 when energized and de-energizes the brake stator 31 when the energization stops. The outer peripheral portion of the stator main body portion 37 has a male screw portion 40 formed with male threads.

[0021] The stator main body portion 37 has a through hole (not shown) through which a bolt (not shown) for fixing the electromagnetic brake device 10 to the electric motor 11 is inserted. The brake-side bracket 21 is provided with a screw hole (not shown) that faces the through hole and allows the bolt to be screwed in. The electromagnetic brake device 10 is fixed to the brake-side bracket 21 by screwing a bolt inserted through the through hole of the stator main body portion 37 into the screw hole of the brake-side bracket 21.

[0022] The stator main body 37 has a plurality of bottomed holes 44 located on the inner circumferential side of the electromagnetic coil 39. The plurality of bottomed holes 44 are arranged at equal intervals in the circumferential direction of the stator main body 37. A coil spring 45 is built into the bottomed hole 44. The central axis of each coil spring 45 is along the axis P of the rotating shaft 15. The coil spring 45 is a biasing member that biases the brake armature 32.

[0023] The brake armature 32 faces the brake stator 31 in the direction of the axis P of the rotating shaft 15. The brake armature 32 is disk-shaped, and the rotating shaft 15 and the brake hub 34 penetrate through the central portion. The brake armature 32 is movable in the direction of the axis P of the rotating shaft 15. Also, one axial end of the coil spring 45 built into the brake stator 31 abuts against the brake stator 31, and the other axial end protruding from the brake stator 31 abuts against the brake armature 32. The coil spring 45 biases the brake armature 32 in a direction away from the brake stator 31 along the axial direction of the rotating shaft 15.

[0024] When the brake stator 31 is excited by energizing the electromagnetic coil 39, the brake armature 32 is attracted to the brake stator 31 against the biasing force of the coil spring 45. When the electromagnetic coil 39 is not energized and the brake stator 31 is non-excited, the brake armature 32 moves in a direction away from the brake stator 31 under the biasing force of the coil spring 45.

[0025] The electromagnetic brake device 10 includes a disk-shaped fixing plate 36. The fixing plate 36 is an annular member, and a through hole 36A is formed at the center of the fixing plate 36. Near the outer peripheral edge of the fixing plate 36, bolt holes 36B for inserting bolts 41 are formed. In the brake stator 31, screw holes 42 that face the bolt holes 36B and allow the bolts 41 to be screwed in are formed. The fixing plate 36 is fixed to the brake stator 31 via bolts 41 and sleeves 46 through which the bolts 41 are inserted. The plurality of bolts 41 penetrate the brake armature 32 and the fixing plate 36 respectively, and fix the brake stator 31 to the electric motor 11. The sleeve 46 is a member for positioning the brake stator 31 in the axial direction of the axis P with respect to the brake side bracket 21. Also, the sleeve 46 defines the movement range of the brake armature 32. The fixing plate 36 is fixed so as to be located at a certain distance from the brake stator 31 along the axial direction of the rotating shaft 15. The brake stator 31 and the fixing plate 36 are arranged side by side in the axial direction of the axis P of the rotating shaft 15. The brake armature 32 is disposed between the brake stator 31 and the fixing plate 36 in the axial direction of the rotating shaft 15.

[0026] The electromagnetic brake device 10 includes a brake hub 34 that rotates integrally with the rotating shaft 15, and a brake plate 35 is integrally fixed to the brake hub 34. The brake plate 35 is disk-shaped, and is disposed between the brake armature 32 and the fixing plate 36 in the axial direction of the axis P of the rotating shaft 15 and is movable in the axial direction of the axis P of the rotating shaft 15. The plate surface of the brake plate 35 is provided with a friction material 47 that abuts against the brake armature 32 in the braking state and a friction material 48 that abuts against the fixing plate 36 in the braking state. An annular retaining member 49 for preventing the brake hub 34 from coming off the rotating shaft 15 is mounted near the end of the rotating shaft 15.

[0027] In the electromagnetic brake device 10 configured as described above, when the electromagnetic coil 39 is excited, the brake armature 32 is attracted to the brake stator 31, the brake armature 32 is separated from the brake plate 35, and the pressing of the brake plate 35 against the fixing plate 36 is released. As a result, the rotating shaft 15 is released from the braking state and can rotate freely without being restricted.

[0028] On the other hand, when the electromagnetic coil 39 is not excited, the brake armature 32 is pressed toward the brake plate 35 by the biasing force of the coil spring 45, and the brake plate 35 is pressed against the fixing plate 36. Therefore, the brake plate 35 is sandwiched between the brake armature 32 and the fixing plate 36. As a result, the rotating shaft 15 is brought into a braking state by the frictional force generated between the brake armature 32 and the brake plate 35. That is, the parking brake is actuated.

[0029] In the electromagnetic brake device 10 of the present embodiment, when the electromagnetic coil 39 is excited by energization, a signal indicating the energization of the electromagnetic coil 39 is transmitted from the electromagnetic brake device 10 to a controller (not shown). When the energization of the electromagnetic coil 39 is cut off, the electromagnetic coil 39 is demagnetized, so a signal indicating energization does not occur. That is, the controller determines whether the electromagnetic brake device 10 is in a non-braking state based on the presence or absence of a signal indicating the energization of the electromagnetic coil 39. The controller is mounted on a forklift and controls the electric motor 11 via a motor driver (not shown) and also controls the electromagnetic brake device 10.

[0030] Incidentally, the electromagnetic brake device 10 of the present embodiment has a forced release mechanism 50 that separates the brake armature 32 from the brake plate 35 when the electromagnetic coil 39 is not operating, and forcibly releases the braking state. The forced release mechanism 50 is provided on the outer peripheral portion of the brake stator 31, and includes a ring member 51 that is displaceable in the axial direction of the rotating shaft 15, and a release piece 52 that is provided on the ring member 51 and is inserted between the fixed plate 36 and the brake armature 32. The ring member 51 and the release piece 52 are formed of a non-magnetic material. The non-magnetic material is, for example, a non-magnetic metal material such as a copper alloy, a nickel alloy, an aluminum alloy, or stainless steel, or a non-metal material such as a ceramic material.

[0031] The ring member 51 is a ring-shaped member. The inner peripheral portion of the ring member 51 has an internal thread portion 53 formed with an internal thread. The internal thread portion 53 is screwed with an external thread portion 40 formed on the outer peripheral portion of the stator main body portion 37 of the brake stator 31. Therefore, the ring member 51 is rotatable in the circumferential direction with respect to the brake stator 31 about the axis P. By rotating the ring member 51 in the circumferential direction, the ring member 51 is displaceable along the direction of the axis P.

[0032] The release piece 52 is integrally formed at the end portion of the ring member 51 on the fixed plate 36 side, and extends toward the axis P in the radial direction of the rotating shaft 15. The tip end portion of the release piece 52 is at a position where it does not interfere with the brake plate 35 in the radial direction of the rotating shaft 15. The end face 54 of the release piece 52 on the brake armature 32 side is a surface substantially parallel to the plate surface of the brake armature 32. The tip end portion of the release piece 52 is at a position where it does not interfere with the brake plate 35 in the radial direction. The end face 55 on the opposite side of the end face 54 of the release piece 52 faces the plate surface of the fixed plate 36. When the electromagnetic brake device 10 is in the braking state, the release piece 52 is separated from the brake armature 32, and when the electromagnetic brake device 10 is in the non-braking state, the position of the ring member 51 with respect to the brake stator 31 is preset so as to be separated from the brake armature 32.

[0033] In this embodiment, the release pieces 52 are arranged at equal intervals in the circumferential direction of the ring member 51. As shown in FIG. 3, the release pieces 52 are located at positions where they do not interfere with the bolts 41. In this embodiment, when the ring member 51 is rotated in one direction (clockwise in FIG. 3), the release pieces 52 approach the brake armature 32 in the direction of the axis P. Further, when the ring member 51 is rotated in the other direction (counterclockwise in FIG. 3), the male screw portion 40 and the female screw portion 53 are set so that the release pieces 52 move away from the brake armature 32 in the direction of the axis P.

[0034] Between a pair of bolts 41 in the circumferential direction, the release pieces 52 are located at positions approaching one of the bolts 41 so that the ring member 51 can rotate in one direction. In this embodiment, since the five bolts 41 are arranged at equal intervals in the circumferential direction, the ring member 51 can be rotated in one direction by a predetermined rotation angle. By the rotation of the ring member 51, the ring member 51 is displaced along the direction of the axis P, the release pieces 52 come into contact with the brake armature 32, and the brake armature 32 separates from the brake plate 35. When the brake armature 32 separates from the brake plate 35, the braking state is released, and the rotating shaft 15 can rotate.

[0035] Next, the procedure for releasing the braking state when the electromagnetic brake device 10 according to this embodiment is de-energized will be described. The operator rotates the ring member 51 in one direction. Since the ring member 51 is screwed with the brake stator 31, when the ring member 51 is rotated in one direction, as shown in FIG. 4(a), the ring member 51 is displaced along the direction of the axis P of the rotating shaft 15. The displacement of the ring member 51 in the direction of the axis P is a displacement in which the release pieces 52 come into contact with and press the brake armature 32. Further, as shown in FIG. 4(b), the release pieces 52 approach from one bolt 41 to the other bolt 41 between the pair of bolts 41 by the rotation of the ring member 51 by a predetermined rotation angle C (for example, about 30 degrees).

[0036] When the release piece 52 contacts and presses against the brake armature 32 due to the rotation of the ring member 51, the brake armature 32 separates from the brake plate 35. When the brake armature 32 separates from the brake plate 35, the braking state is released and the rotating shaft 15 becomes rotatable.

[0037] The electromagnetic brake device 10 of this embodiment has the following effects. (1) Although the ring member 51 is provided on the outer peripheral portion of the brake stator 31, the female screw portion 53 on the inner peripheral portion of the ring member 51 is screwed with the male screw portion 40 on the outer peripheral portion of the brake stator 31. Therefore, when the ring member 51 is rotated in the circumferential direction, the ring member 51 is displaced along the axial center P direction with respect to the brake stator 31. Accordingly, even during braking in the non-energized state, due to the displacement of the ring member 51, the release piece 52 contacts the brake armature 32 and the brake armature 32 can be separated from the brake plate 35. According to this embodiment, it is possible to manually release the braking state regardless of the presence or absence of space in the axial direction of the electromagnetic brake device 10.

[0038] (2) Since a plurality of release pieces 52 are provided in the circumferential direction of the ring member 51, when the release piece 52 separates the brake armature 32 from the brake plate 35 during brake operation, it is possible to make it difficult for the load on the brake armature 32 to be biased. Further, even when the ring member 51 is rotated, a non-braking state can be realized without the release piece 52 interfering with the bolt 41.

[0039] (3) Since the release piece 52 is formed of a non-magnetic material, the release piece 52 is not magnetized by the energization of the electromagnetic coil 39, and the brake armature 32 is not attracted to the brake plate 35 due to the magnetization of the release piece 52.

[0040] (Second Embodiment) Next, an electromagnetic brake device according to a second embodiment will be described. The configuration of the forced release mechanism of the electromagnetic brake device of this embodiment is different from that of the first embodiment. In this embodiment, for the same configuration as that of the first embodiment, the description of the first embodiment is incorporated and common reference numerals are used.

[0041] As shown in FIG. 5, in the electromagnetic brake device 60 of this embodiment, the bolt 41 is disposed closer to the radial center side. Therefore, the outer diameter of the brake plate 35 is set so as not to interfere with the bolt 41. The forced release mechanism 61 has a ring member 62 and a release piece 63. The ring member 62 and the release piece 63 are formed of a non-magnetic metal. The inner peripheral portion of the ring member 62 has an internal thread portion 64 in which an internal thread is formed. The internal thread portion 64 is screwed with an external thread portion 40 formed on the outer peripheral portion of the stator main body portion 37 in the brake stator 31.

[0042] The release piece 63 is integrally formed at the end portion of the ring member 62 on the fixed plate 36 side, and extends in the direction of the axis P in the radial direction of the rotating shaft 15. The tip of the release piece 63 is at a position where it does not interfere with the brake plate 35 in the radial direction of the rotating shaft 15. The end face 65 of the release piece 52 on the brake armature 32 side is a plane substantially parallel to the plate surface of the brake armature 32. The tip of the release piece 52 is at a position where it does not interfere with the brake plate 35 in the radial direction. The end face 66 on the opposite side of the end face 54 of the release piece 52 faces the plate surface of the fixed plate 36. The bolt 41 is inserted through the sleeve 46.

[0043] In this embodiment, the release piece 63 is continuously formed over the circumferential direction of the ring member 62. As shown in FIG. 6, the release piece 63 is located radially outside the bolt 41 and the sleeve 46 so as not to interfere with the bolt 41 and the sleeve 46. In this embodiment, when the ring member 62 is rotated in one direction (clockwise in FIG. 6), the release piece 63 approaches the brake armature 32. The external thread portion 40 and the internal thread portion 64 are set such that when the ring member 62 is rotated in the other direction (counterclockwise in FIG. 6), the release piece 63 moves away from the brake armature 32.

[0044] According to the electromagnetic brake device 60 of the present embodiment, effects equivalent to the effects (1) and (3) of the first embodiment are achieved. Further, in the present embodiment, since the release piece 63 is continuously formed over the circumferential direction of the ring member 62, it is possible to suppress the deviation of the load on the brake armature 32 due to the contact of the release piece 63. As a result, it is possible to suppress the deformation of the brake armature 32 due to contact with the release piece 63. Furthermore, the rotation angle of the ring member 62 is not restricted by the bolt 41, and the degree of freedom in adjusting the position of the release piece 63 in the axial center P direction with respect to the brake armature 32 is higher than that of the first embodiment.

[0045] (Alternative Example 1) Next, a forced release mechanism 70 according to Alternative Example 1 shown in FIG. 7(a) will be described. The forced release mechanism 70 includes a ring member 71 and a release piece 72. The ring member 71 has an axial length so as to extend toward the fixing plate 36 more than the release piece 72. Therefore, the ring member 71 is positioned across the fixing plate 36 and the brake stator 31 and covers the outer periphery of the brake plate 35. Since the ring member 71 covers the outer periphery of the brake plate 35, it is possible to prevent foreign matter from entering the brake plate 35 from around the electromagnetic brake device.

[0046] (Alternative Example 2) Next, a forced release mechanism 80 according to Alternative Example 2 shown in FIG. 7(b) will be described. The forced release mechanism 80 includes a ring member 81 and a release piece 82. The ring member 81 has an axial length so as to extend toward the fixing plate 83 more than the release piece 82. The fixing plate 83 of the present embodiment has a male screw portion 84 formed on the outer peripheral portion. The inner peripheral portion of the ring member 81 has a female screw portion 85 formed with a female screw. The female screw portion 85 is formed on the fixing plate 83 side more than the release piece 82 and is screwed with the male screw portion 84 formed on the outer peripheral portion of the fixing plate 83. Therefore, when the ring member 81 is rotated in the circumferential direction with respect to the brake stator 31, it is displaceable along the axial center P direction.

[0047] The present invention is not limited to the above-described embodiments (including alternative examples), and various modifications are possible within the scope of the gist of the invention. For example, the following modifications may be made.

[0048] ○ In the above-described embodiments (including alternative examples), other members or other devices adjacent to the brake stator in the axial direction of the electromagnetic brake device were not shown, but other members or other devices approaching the brake stator may exist. ○ In the above-described embodiments (including alternative examples), the release piece was assumed to be formed of a non-magnetic material, but it is not limited thereto. When the influence of magnetization of the release piece is small even if the release piece is a magnetic material, a magnetic material may be used. ○ In the first and second embodiments and alternative examples, the ring member was formed over the entire circumference, but it is not limited thereto. The ring member may have a gap in the circumferential direction.

Explanation of Reference Numerals

[0049] 10, 60 Electromagnetic brake device 11 Electric motor 12 Rotor 13 Stator 15 Rotating shaft 19 Output side bracket 21 Brake side bracket 22 Bearing 23 Output shaft 31 Brake stator 32 Brake armature 36, 83 Fixed plate 34 Brake hub 35 Brake plate 39 Electromagnetic coil 40, 84 Male screw portion 41 Bolt 45 Coil spring 50, 61, 70, 80 Forced release mechanism 51, 62, 71, 81 Ring member 52, 63, 72, 82 Release piece 53, 64, 85 Female screw portion C Rotation angle P-axis center

Claims

1. A brake stator, a rotating shaft rotatable relative to the brake stator, a brake plate fixed to the rotating shaft, a brake armature interposed between the brake stator and the brake plate, an adsorption mechanism for adsorbing the brake armature to the brake stator by energization, a fixing plate that sandwiches the brake plate together with the brake armature in a braking state, a biasing member that biases the brake armature in a direction away from the brake stator, In an electromagnetic brake device having a forced release mechanism that separates the brake armature from the brake plate when the adsorption mechanism is inoperative and forcibly releases the braking state, The forced release mechanism includes a ring member provided on an outer peripheral portion of the brake stator or the fixing plate and displaceable along the axial direction of the rotating shaft, a release piece provided on the ring member and inserted between the fixing plate and the brake armature, The outer peripheral portion has a male thread portion, The inner peripheral portion of the ring member has a female thread portion that engages with the male thread portion. An electromagnetic brake device characterized by this.

2. The brake stator has a plurality of bolts arranged in the circumferential direction and fixing the fixing plate to the brake stator, The electromagnetic brake device according to claim 1, wherein a plurality of the release pieces are provided in the circumferential direction of the ring member and are arranged so as not to interfere with the plurality of bolts.

3. The electromagnetic brake device according to claim 1, wherein the release piece is continuously formed over the circumferential direction of the ring member.

4. The electromagnetic brake device according to any one of claims 1 to 3, wherein the release piece is formed of a non-magnetic material.

5. The electromagnetic brake device according to any one of claims 1 to 3, wherein the ring member covers the outer periphery of the brake plate.

Images