Electromagnetic brake system

Abstract

The present invention provides an electromagnetic brake device that can prevent the lining from rotating while in frictional contact with other components. [Solution] The electromagnetic brake device 1 comprises a lining holder 10, a friction disc 20, an armature 30, a biasing member 40, an electromagnet 50, and a lining 60, wherein the electromagnet 50 has a yoke 52 on the armature 30 side having an inner circumferential annular end face 55 and an outer circumferential annular end face 54 centered on the central axis 3a, the lining holder 10, the armature 30, and the yoke 52 are made of magnetic material, the lining holder 10 has a convex portion 12 that protrudes toward the inner circumferential annular end face 55 at a position opposite to the inner circumferential annular end face 55 of the yoke 52, and both the convex portion 12 and the armature 30 have a region that overlaps with the inner circumferential annular end face 55 of the yoke 52 when viewed from a direction along the rotation axis 3.

Description

Technical Field

[0001] The present invention relates to an electromagnetic brake device.

Background Art

[0002] Conventionally, there is known an electromagnetic brake device in which when an electromagnetic coil is in a non-energized state, a brake is applied by the biasing force of a biasing means (spring body), and when it is in an energized state, the brake is released (see, for example, Patent Document 1).

[0003] FIG. 6 is a cross-sectional view showing an electromagnetic brake device 900 (hereinafter referred to as a conventional electromagnetic brake device 900) described in Patent Document 1. As shown in FIG. 6, the conventional electromagnetic brake device 900 includes a lining holder 910 that rotates integrally with a rotating shaft 903 and is slidable in the direction of the central axis 903a of the rotating shaft, a friction disk 920 that is coaxially opposed and fixed to one side of the lining holder 910, an armature 930 that is coaxially opposed to the other side of the lining holder 910 and is slidable in the direction of the central axis 903a, and a biasing member 940 that presses the armature 930 against the friction disk 920 with the lining holder 910 interposed therebetween to restrain the rotation of the rotating shaft 903, and an electromagnet 950 that can generate a magnetic force to attract the armature 930 in a direction away from the lining holder 910 against the biasing force of the biasing member 940 in order to release the rotation restraint state of the rotating shaft 903.

[0004] In the conventional electromagnetic brake device 900, linings 960 are provided on the surfaces of the friction disk 920 facing the lining holder 910 and on the surfaces of the armature facing the lining holder 910, respectively.

[0005] The electromagnet 950 has a ring shape centered on the central axis 903a and includes a yoke 952 having an annular recess 953 having a certain depth from the armature 930 side, and an electromagnetic coil 951 arranged in the annular recess 953. The armature 930 and the yoke 952 are made of ferromagnetic material.

[0006] The operation of the conventional electromagnetic brake device 900 is as follows: In other words, when the electromagnetic coil 951 is not energized, the biasing force of the biasing member 940 (for example, a spring) presses the armature 930 against the lining holder 910, and consequently, the lining holder 910, which is pressed against the armature 930, presses against the lining 960 of the friction disc 920, thereby applying a brake.

[0007] Furthermore, when the electromagnetic coil 951 is energized, a magnetic path is formed through the yoke 952 and armature 930, which are made of ferromagnetic material, and a magnetic force is generated in the direction that attracts the armature 930 to the yoke 952. This magnetic force overcomes the biasing force of the biasing member 940, releasing the lining holder 910 from being pressed against the friction disc 920. As a result, the lining holder 910 separates from the lining 960 of the friction disc 920, and the armature 930 separates from the lining holder 910, releasing the brake. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 11-82574 [Patent Document 2] Japanese Patent Publication No. 2008-39107 [Overview of the project] [Problems that the invention aims to solve]

[0009] However, when the electromagnetic coil 951 is energized and the lining holder 910 is released from being pressed against the friction disc 920, the lining holder 910 becomes slidable in the direction along the central axis 903a of the rotation shaft 903. However, because the sliding position of the lining holder 910 becomes uncertain, there is a problem that the lining 960 provided on the lining holder 910 may rotate while in frictional contact with the armature 930 or friction disc 920. When the lining holder 910 (lining 960) rotates while in frictional contact with the armature 930 or friction disc 920, noise (e.g., friction noise or rubbing noise) may be generated, and wear particles may be produced, which is undesirable.

[0010] Specifically, if the lining holder 910, which rotates integrally with the rotating shaft 903, slides toward the armature 930, there is a risk that the lining holder 910 (lining 960) will rotate while making frictional contact with the armature 930. Conversely, if the lining holder 910 slides toward the friction disk 920, there is a risk that the lining holder 910 (lining 960) will rotate while making frictional contact with the friction disk 920.

[0011] This is a problem that can occur not only when the lining 960 is provided on the lining holder 910, but also when the lining 960 is provided on the friction disc 920 or the armature 930.

[0012] The present invention was made to solve the above-mentioned problems, and aims to provide an electromagnetic brake device that can prevent the lining from rotating while in frictional contact with other components. [Means for solving the problem]

[0013] According to the electromagnetic brake device of the present invention, a lining holder that rotates integrally with the rotating shaft and is slidable in the direction of the central axis of the rotating shaft; a friction disk that is coaxially opposed to and fixed on one side of the lining holder; an armature that is coaxially opposed to and slidable in the direction of the central axis on the other side of the lining holder; a biasing member that restrains the rotation of the rotating shaft by pressing the armature against the friction disk while sandwiching the lining holder; and a magnetic force that attracts the armature away from the lining holder in the opposite direction to the biasing force of the biasing member in order to release the rotational restraint of the rotating shaft. The device comprises an electromagnet capable of generating a magnetic field, and a lining formed on both sides of the lining holder, or on the surface of the friction disk and the armature on the lining holder side, wherein the electromagnet has a yoke on the armature side having an inner annular end face and an outer annular end face centered on the central axis, the lining holder and the armature are made of a magnetic material, the lining holder has a convex portion projecting toward the inner annular end face at a position opposite the inner annular end face of the yoke, and both the convex portion and the armature have a region that overlaps with the inner annular end face of the yoke when viewed from a direction along the rotation axis. [Effects of the Invention]

[0014] According to the electromagnetic brake device of the present invention, the lining holder, armature, and yoke are made of magnetic material, and the lining holder has a protrusion that projects toward the inner annular end face of the yoke at a position opposite to the inner annular end face of the yoke, and both the protrusion and the armature are located in a position that overlaps with the inner annular end face of the yoke when viewed from a direction along the axis of rotation, so when the electromagnetic coil is energized, a magnetic path is formed extending from the yoke to the armature, and a magnetic path is also formed extending from the yoke to the lining holder. Therefore, a magnetic force is generated that attracts not only the armature but also the lining holder to the yoke, and the sliding position is fixed, so that the lining does not rotate while in frictional contact with other members. As a result, it is possible to prevent the generation of noise (e.g., friction noise or rubbing noise) and wear particles. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing an electromagnetic brake device 1 according to an embodiment. [Figure 2] This is an enlarged cross-sectional view of the main part of the electromagnetic brake device 1 according to the embodiment. [Figure 3] This is a cross-sectional view illustrating the magnetic path and magnetic force of the electromagnetic brake device 1 according to this embodiment. [Figure 4] This is a cross-sectional view shown to illustrate the magnetic path and magnetic force of the electromagnetic brake device 200 related to the background technology. [Figure 5] This figure shows the results of the magnetic force analysis of the electromagnetic brake device 1 according to the embodiment. [Figure 6] This is a cross-sectional view showing a conventional electromagnetic brake device 900. Reference numeral 980 indicates a fastening screw. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments of the electromagnetic brake device according to the present invention will be described with reference to the drawings. Each drawing is a schematic diagram showing an example, and does not necessarily strictly reflect actual dimensions, ratios, etc. Further, in each embodiment, for the same components as those in the embodiment in terms of the basic configuration and features, the same reference numerals as those in the embodiment are used, or the attachment of reference numerals is omitted, and the description of those components is omitted.

[0017] [Embodiment] 1. Configuration of the electromagnetic brake device 1 according to the embodiment FIG. 1 is a cross-sectional view showing the electromagnetic brake device 1 according to the embodiment. FIG. 2 is an enlarged cross-sectional view of the main part of the electromagnetic brake device 1 according to the embodiment. As shown in FIG. 1, the electromagnetic brake device 1 according to the embodiment is attached to, for example, the rotating shaft 3 of the motor 2, and is used to switch the rotating shaft 3 between a rotation-restrained state (brake state) and a freely rotatable state (brake release state).

[0018] As shown in FIGS. 1 and 2, the electromagnetic brake device 1 according to the embodiment includes a lining holder 10, a friction disk 20, an armature 30, a biasing member 40, an electromagnet 50, a lining 60, and a driving boss 70, and the electromagnet 50, the armature 30, the lining holder 10, and the friction disk 20 are arranged in this order from the motor 2 side. Linings 60 are provided on the surfaces of the friction disk 20 facing the lining holder 10 and on the surface of the armature facing the lining holder 10, respectively. The lining holder 10 and the driving boss 70 rotate integrally with the rotating shaft 3.

[0019] The electromagnet 50 has an annular shape centered on the central axis 3a, and includes a yoke 52 having an annular recess 53 with a certain depth on the armature 30 side, and an electromagnetic coil 51 annularly mounted in the annular recess 53, and is sealed by a sealing body 54.

[0020] The electromagnetic coil 51 is positioned within the annular recess 53 and wound around the central axis 3a. When current is passed through the electromagnetic coil 51, a magnetic field is generated in the yoke 52, and a magnetic path is formed in the yoke 52 and the armature 30. This generates a magnetic force that attracts the armature 30 to the electromagnet 50.

[0021] The yoke 52 has an inner ring portion 55 that forms the side wall of the annular recess 53 on the side of the rotation axis 3, an outer ring portion 56 that forms the side wall on the outer circumference side of the annular recess 53, and a bottom portion 57, and the annular recess 53 is formed by the inner ring portion 55, the outer ring portion 56 and the bottom portion 57. An inner circumferential annular end face 55a is formed on the surface of the inner ring portion 55 on the armature 30 side, and an outer circumferential annular end face 56a is formed on the surface of the outer ring portion 56 on the armature 30 side.

[0022] The outer ring portion 56 of the yoke 52 has circular recesses 58 for mounting springs, which extend in the direction of the central axis 3a at predetermined angular intervals and have a predetermined depth. A biasing member 40 (for example, a coil spring) is housed in these circular recesses 58. The tip of the biasing member 40 protrudes above the height of the inner circumferential annular end face 55a and the outer circumferential annular end face 56a and is connected to the armature 30. In addition, bolt insertion holes 59 are formed in the outer ring portion 56 of the yoke 52 between the circular recesses 58 along the outer edge. The circular recesses 58 are formed at predetermined angular intervals along the outer edge when viewed in plan.

[0023] The armature 30 is positioned coaxially opposite the lining holder 10 on the other side and is configured to slide in the direction of the central axis 3a (up and down direction in Figure 1). The armature 30 has an annular shape with a central hole 31 in the center, through which the rotating shaft 3 passes. The stopper 72 of the driving boss 70 and the protrusion 12 of the lining holder 10 are positioned between the rotating shaft 3 and the side wall of the central hole 31, and are spaced apart from each other. A biasing member 40 extending from the yoke 52 is connected to a predetermined position on the outer circumference of the armature 30, and the position of the armature 30 is adjusted according to the expansion and contraction of the biasing member 40. The lining 60 is positioned on the side of the armature 30 opposite to the electromagnet 50. The armature 30 is made of a ferromagnetic material. Furthermore, the armature 30 has a region that overlaps with the inner annular end face 55a of the yoke 52 when viewed from a direction along the rotation axis 3. When the radial length of the inner annular end face 55a is a, and the radial length of the region where the armature 30 and the inner annular end face 55a of the yoke 52 overlap is J, the condition 0.25 ≤ J / a ≤ 0.8 is satisfied.

[0024] The lining holder 10 rotates integrally with the rotating shaft 3 and is configured to slide in the direction of the central axis 3a of the rotating shaft 3. The lining holder 10 has a substantially annular shape with a central hole 15 of a predetermined shape in the center. The cylindrical portion 71 of the driving boss 70 is inserted through the central hole 15 of the lining holder 10, and the driving boss 70 and the lining holder 10 rotate in accordance with the rotation of the rotating shaft 3, and the lining holder 10 is configured to slide in the direction along the rotating shaft. The lining holder 10 is made of a magnetic material. The outer diameter of the lining holder 10 is shorter than the outer diameter of the friction disk 20 and the lining holder 10.

[0025] The lining holder 10 has a main body portion 11, a protrusion 12 that projects toward the inner annular end face 55a of the yoke 52 at a position opposite to the inner annular end face 55a, an inner circumferential portion 13 that contacts the driving boss 70, and an outer circumferential portion 14.

[0026] The main body portion 11 and the inner circumference portion 13 have an annular disc shape with a predetermined thickness. The lining holder 10 is configured to slide in a direction along the central axis 3a of the rotation shaft 3, but when the armature 30 is attracted to the electromagnet 50, the inner circumference portion 13 comes into contact with the stopper 72 of the driving boss 70, preventing the lining holder 10 from sliding any further toward the yoke 52, thereby preventing the lining holder 10 from coming into contact with the lining 60, armature 30, or yoke 52.

[0027] The outer periphery 14 is formed in a position opposite to the lining 60 provided on the armature 30 and friction disc 20. When the electromagnetic coil 51 is not energized, the outer periphery 14 is in frictional contact with the lining 60 provided on the armature 30 and friction disc 20, resulting in a rotationally restrained state (braking state).

[0028] The protrusion 12 is positioned opposite the inner circumferential annular end face 55a of the yoke 52 (positioned to overlap with the inner circumferential annular end face 55a of the yoke 52 when viewed from the direction along the axis of rotation) and protrudes toward the inner circumferential annular end face 55a, forming an annular shape. When the radial length of the inner circumferential annular end face is a and the radial length of the protrusion is b, the condition 0.25 ≤ b / a ≤ 0.75 is satisfied.

[0029] The protrusion 12 is positioned between the armature 30 and the stopper 72 of the driving boss 70, at a distance from each of them. The height of the protrusion 12 from the main body 11 is such that the tip of the protrusion 12 does not come into contact with the inner annular end face even when the lining holder 10 is closest to the electromagnet 50. It is preferable that the protrusion 12 is formed around the entire circumference, but it is not necessary that it be formed around the entire circumference.

[0030] The friction disc 20 is an annular disc fixed to one side of the lining holder 10 in a coaxial position opposite to it. A through hole 21 is formed in the center of the friction disc 20, and the rotating shaft 3 and the driving boss 70 pass through the through hole 21. Screw holes 22 are formed along the outer edge of the friction disc 20 at predetermined angular intervals, and fastening screws 80 are screwed into bolt insertion holes 59 of the yoke 52 through these screw holes and cylindrical spacers 82 placed inside the screw holes. An annular lining 60 is formed on the lining holder 10 side of the friction disc 20.

[0031] The linings 60 are formed on the friction disk 20 and the surface of the armature 30 on the side facing the lining holder 10. When the electromagnetic coil 51 is not energized, the two linings 60 are in frictional contact with the lining holder 10, sandwiching it between them, and the lining holder 10 is rotationally restrained.

[0032] The driving boss 70 has a cylindrical portion 71 and a stopper 72 positioned at the bottom of the cylindrical portion 71 and protruding outward. A central through-hole 73 is formed in the center of the cylindrical portion 71 and the stopper 72, large enough to accommodate the rotating shaft 3. The rotating shaft 3 passes through the central through-hole 73. The driving boss 70 is fixed to the rotating shaft 3 with an adhesive (not shown).

[0033] The cylindrical portion 71 has a shape in which a part of its outer circumference has been flattened, and its side surface has both an arced portion and a straight portion. The central hole 15 of the lining holder 10 has a shape corresponding to the outer shape of the cylindrical portion 71, and the lining holder 10 is positioned to fit into the cylindrical portion 71. As a result, the driving boss 70 and the lining holder 10 can rotate together, and the lining holder 10 can slide in the direction along the rotation axis 3.

[0034] The stopper 72 has a structure that protrudes from the cylindrical portion 71 to the outer peripheral side. In the embodiment, it has the same thickness as the armature 30, but it does not necessarily have to be the same thickness. The upper surface of the stopper 72 is on the same plane as the upper surface of the armature 30 when the brake is applied. When the distance between the inner peripheral portion 13 of the lining holder 10 and the stopper 72 of the driving boss 70 is A, and the distance between the convex portion 12 of the lining holder 10 and the inner peripheral annular end face 55a of the yoke 52 is B, the stopper 72 satisfies the relationship A < B. Thereby, the stopper 72 can prevent the convex portion 12 of the lining holder 10 from contacting the yoke 52 or the lining holder 10 from contacting the lining 60 when the electromagnetic coil 951 is in an energized state.

[0035] 2. Magnetic Circuit in the Electromagnetic Brake Device 1 in the Embodiment Before explaining the state of the magnetic circuit in the electromagnetic brake device 1 according to Embodiment 1, the state of the magnetic circuit in the electromagnetic brake device 200 according to the background art will be explained. FIG. 3 is a cross-sectional view shown for explaining the magnetic circuit and magnetic force of the electromagnetic brake device 1 according to the embodiment. FIG. 4 is a cross-sectional view shown for explaining the magnetic circuit and magnetic force of the electromagnetic brake device 200 according to the background art.

[0036] The electromagnetic brake device 200 according to the background art basically has the same configuration as the electromagnetic brake device 1 according to the embodiment. However, as shown in FIG. 4, the convex portion 212 of the lining holder 210 is formed over substantially the entire area of the inner peripheral annular end face 255a of the yoke 252, and the armature 230 is different from the electromagnetic brake device 1 according to the embodiment in that it is not (does not overlap) at a position overlapping the inner peripheral annular end face 255a of the yoke 252 when viewed from the direction along the rotation axis 203. The electromagnetic brake device 200 according to the background art is an electromagnetic brake device having the same configuration as Patent Document 2.

[0037] In the electromagnetic brake device 200 relating to the background technology, when the electromagnetic coil 251 is energized, a magnetic flux is formed on the yoke 252. When viewed from a direction along the rotation axis 203, the protrusion 212 of the lining holder 210 is formed over almost the entire inner annular end face 255a of the yoke 252. Therefore, almost all of the magnetic field lines extending from the inner annular end face 255a of the yoke 252 enter the protrusion 212. Then, a portion of the magnetic flux extending to the protrusion 212 extends from the side surface of the protrusion 212 to the armature 230, and the remainder extends to the armature 230 near the outer circumference via the lining holder 210. The magnetic field lines extending to the armature 230 return to the yoke 252 through the gap between the armature 230 and the yoke 252.

[0038] Therefore, when the electromagnetic coil 251 is energized, a magnetic force is generated that attracts the armature 230 to the outer annular end face 256a of the yoke 252. However, on the inner annular end face 255a side, almost no magnetic force is generated that attracts the armature 230 to the yoke 252, and there is a risk that it will not be able to sufficiently overcome the biasing force of the biasing member 240. Therefore, it is thought that the armature 230 may not be sufficiently separated from the lining holder 210, and the brake may not be reliably released.

[0039] Furthermore, in the electromagnetic brake device 200 relating to the background technology, the magnetic field lines that enter the protrusion 212 of the lining holder from the yoke 252 are formed such that a portion of them extend from the side of the protrusion 212 to the armature 230. As a result, magnetic force is generated not in a way that attracts the armature 230 to the inner circumferential annular end face 255a (magnetic force is generated in the vertical direction in Figure 4), but rather in a way that attracts the armature 230 to the side of the protrusion 212 (magnetic force is generated in the horizontal direction in Figure 4). Therefore, it may not be possible to sufficiently attract the armature 230 towards the yoke 252, and the armature 230 may not be sufficiently separated from the lining holder 210. Consequently, it is thought that the brake may not be reliably released.

[0040] On the other hand, in the electromagnetic brake device 1 according to the embodiment, when the electromagnetic coil 51 is energized, a magnetic path is formed in the yoke 52, similar to the electromagnetic brake device 200 in the background art. As shown in Figure 3, both the protrusion 12 and the armature 30 are located in positions that overlap with the inner annular end face 55a of the yoke 52 when viewed from a direction along the rotation axis 3. Therefore, the magnetic field lines extending from the inner annular end face 55a of the yoke 52 are divided into those extending from the tip of the protrusion 12 to the lining holder 10 and those extending to the armature 30 through the region overlapping with the inner annular end face 55a of the armature 30.

[0041] Therefore, in the electromagnetic brake device 1 according to this embodiment, magnetic forces are generated that attract the armature 30 to the outer annular end face 56a and to the inner annular end face 55a. Consequently, the armature 30 can be attracted to the yoke 52 with a stronger magnetic force than in the electromagnetic brake device 200 relating to the background art. Consequently, the biasing force of the biasing member 40 can be sufficiently overcome, and the armature 30 can be sufficiently separated from the lining holder 10. As a result, the brake can be reliably released.

[0042] Furthermore, since a magnetic field path is formed from the yoke 52 to the armature 30, the magnetic field lines (magnetic paths) extending from the protrusion 12 to the lining holder 10 have almost no component extending from the protrusion 12 to the armature 30, and the magnetic force hardly acts between the armature and the protrusion. Therefore, from this viewpoint as well, the armature 30 can be sufficiently separated from the lining holder 10, and the brake can be reliably released.

[0043] 3. Effects of the electromagnetic brake device 1 according to this embodiment According to the electromagnetic brake device 1 of this embodiment, the lining holder 10, armature 30, and yoke 52 are made of magnetic material. The lining holder 10 has a protrusion 12 that projects toward the inner annular end face 55a of the yoke 52 at a position opposite to the inner annular end face 55a of the yoke 52. Both the protrusion 12 and the armature 30 are located in positions that overlap with the inner annular end face 55a of the yoke 52 when viewed from a direction along the central axis 3a of the rotation axis 3. Therefore, when the electromagnetic coil 51 is energized, a magnetic path is formed not only in the yoke 52 and armature 30, but also in the yoke 52 and lining holder 10, generating a magnetic force that causes the armature 30 and lining holder 10 to move toward the yoke 52. Consequently, the lining holder 10 and armature 30 are attracted to the yoke 52 and their sliding positions are fixed, preventing the lining 60 from rotating while in frictional contact with other members. As a result, it becomes possible to prevent noise generation and the generation of wear particles.

[0044] Furthermore, according to the electromagnetic brake device 1 of the embodiment, when viewed from a direction along the central axis 3a of the rotating shaft 3, the armature 30 and the inner circumferential annular end face 55a of the yoke 52 overlap. When the radial length of the inner circumferential annular end face 55a is a, and the radial length of the region where the armature 30 and the inner circumferential annular end face 55a of the yoke 52 overlap is J, the condition 0.25 ≤ J / a ≤ 0.8 is satisfied. Therefore, sufficient magnetic force can be generated to attract the armature 30 to the electromagnet 50, and sufficient magnetic force can also be generated to attract the lining holder 10 to the electromagnet 50.

[0045] Furthermore, the reason J / a is set to 0.25 or higher is that if J / a is less than 0.25, the overlapping area between the inner annular end face 55a and the armature 30 is too small, resulting in a small magnetic force acting between the armature 30 and the inner annular end face 55a, which may prevent the armature 30 from being sufficiently attracted to the electromagnet 50. Also, the reason J / a is set to 0.8 or lower is that if J / a exceeds 0.8, the overlapping area between the inner annular end face 55a and the armature 30 is too large, resulting in a small magnetic force acting between the lining holder 10 and the inner annular end face 55a, which may prevent the lining holder 10 from being sufficiently attracted to the electromagnet 50, and may prevent the brake from being released even when the brake is released.

[0046] Furthermore, according to the electromagnetic brake device 1 of this embodiment, when the radial length of the inner circumferential annular end face 55a is a and the radial length of the protrusion 12 is b, the value of 0.25 ≤ b / a ≤ 0.75 is satisfied. Therefore, when the electromagnetic coil 51 is energized, both the lining holder 10 and the armature 30 can be pulled toward the electromagnet 50.

[0047] The reason why b / a is set to 0.25 or higher is that if b / a is less than 0.25, the area where the inner annular end surface 55a and the protrusion 12 overlap is too small, resulting in a small magnetic force acting between the protrusion of the lining holder 10 and the inner annular end surface 55a, which may prevent the lining holder 10 from being sufficiently attracted to the electromagnet 50. Furthermore, the reason why b / a is set to 0.75 or lower is that if b / a exceeds 0.75, the area where the inner annular end surface 55a and the armature 30 overlap becomes too small, resulting in a small magnetic force acting between the armature 30 and the inner annular end surface 55a, which may prevent the armature 30 from being sufficiently attracted to the electromagnet 50.

[0048] Furthermore, according to the electromagnetic brake device 1 of this embodiment, a stopper 72 is provided which is attached to the rotating shaft 3 and prevents the lining holder 10 from coming into contact with the lining 60, armature 30, or yoke 52 when the lining holder 10 is attracted to the electromagnet 50. As a result, when the electromagnetic coil 51 is energized, it is possible to prevent the lining holder 10 from sliding too far towards the electromagnet 50.

[0049] Furthermore, according to the electromagnetic brake device 1 of this embodiment, since the driving boss 70 and the rotating shaft 3 are bonded together using an adhesive, the driving boss 70 and the rotating shaft 3 can be properly joined even when the electromagnetic brake device is used for a motor with large vibrations.

[0050] [Example Test] The test example is designed to confirm that when the electromagnetic coil is energized, a magnetic path is formed extending from the yoke to the armature, as well as a magnetic path extending from the yoke to the lining holder. Figure 5 shows the results of the magnetic force analysis of the electromagnetic brake device 1 according to this embodiment.

[0051] 1. Examination Method An electromagnetic brake device having a configuration similar to the electromagnetic brake device 1 according to Embodiment 1 was used as a test example. Computer simulations were performed to show the magnetic flux density at predetermined points on the yoke 52, protrusion 12, and armature 30 when the electromagnetic coil was energized, using color coding, and the direction of the magnetic field lines was indicated by arrows and plotted. In the test example, the radial width of the region where the armature 30 and the inner annular end face 55a of the yoke 52 overlap is 1:1, and the radial length of the protrusion 12 is approximately half the width of the inner annular end face 55a. In addition, the bottom 57 side of the inner ring portion 55 is cut at an angle.

[0052] 2. Test Results As can be seen from Figure 5, magnetic field lines extending from the inner annular end face 55a extend to the region of the armature 30 that overlaps with the inner annular end face 55a and to the protrusion 12, respectively. Therefore, it was confirmed that many magnetic field lines extend between the armature 30 and the inner annular end face 55a, and that a strong magnetic field is formed between the armature 30 and the inner annular end face 55a. Thus, it was confirmed that a magnetic field is formed that attracts the armature 30 to the inner annular end face 55a.

[0053] Furthermore, many magnetic field lines extended between the protrusion 12 and the inner annular end face 55a, confirming that a strong magnetic field was formed between the protrusion 12 and the inner annular end face 55a. Therefore, it was confirmed that a magnetic field was formed that attracted the lining holder 10 to the inner annular end face 55a. As a result, the sliding position of the lining holder 10 was stabilized, and it was confirmed that the lining holder 10 could be prevented from rotating while in frictional contact with the armature 30 and friction disk 20.

[0054] Furthermore, the magnetic field lines extending from the protrusion 12 showed almost no component extending from the side of the protrusion 12 to the armature 30. Therefore, unlike in the case of Patent Document 2, it was confirmed that no magnetic force was generated that attracted the armature 30 toward the protrusion.

[0055] Although the present invention has been described above based on the embodiments described above, the present invention is not limited to the embodiments described above. It can be implemented in various forms without departing from the spirit of the invention, and for example, the following modifications are also possible.

[0056] (1) The number, material, shape, position, size, etc. of the components described in the above embodiments are illustrative examples and can be changed within the scope that does not impair the effects of the present invention.

[0057] (2) In the above embodiments, the lining was attached to the armature and friction disk, but the present invention is not limited thereto. The lining may also be attached to both sides of the lining holder.

[0058] (3) In each of the above embodiments, the driving boss and the rotating shaft were bonded together using an adhesive, but the present invention is not limited thereto. The driving boss and the rotating shaft may also be connected by screw fastening, shrink fitting, cold fitting, etc. [Explanation of Symbols]

[0059] 1,200,900…Electromagnetic brake device, 2…Motor, 3,203,903…Rotating shaft, 3a,203a,903a…Central axis, 10,210,910…Lining holder, 11…Main body, 12,212…Protrusion, 13…Inner circumference, 14…Outer circumference, 15…Center hole, 20,220,930…Friction disc, 21…Through hole, 22…Screw hole, 30,230,930…Armature, 31…Center hole, 40,240,940…Biasing part Material, 50, 250, 950…Electromagnet, 51…Electromagnetic coil, 52, 252, 952…Yoke, 53…Annular recess, 54…Sealing body, 55…Inner ring, 55a, 255a…Inner circumferential annular end face, 56…Outer ring, 56a…Outer circumferential annular end face, 57…Bottom, 58…Circular recess, 59…Bolt insertion hole, 60, 960…Lining, 70…Driving boss, 71…Cylindrical part, 72…Stopper, 73…Center through hole, 80…Fastening screw, 82…Cylindrical spacer

Claims

1. A lining holder that rotates integrally with the rotating shaft and is slidable in the direction of the central axis of the rotating shaft, A friction disk is coaxially positioned opposite and fixed to one side of the lining holder, An armature is coaxially positioned opposite the lining holder on the other side and is slidable in the direction of the central axis, A biasing member that restrains the rotation of the rotating shaft by pressing the armature against the friction disk while the lining holder is sandwiched between them, An electromagnet capable of generating a magnetic force that attracts the armature away from the lining holder, in order to release the rotational constraint of the rotation shaft, The lining holder has lining formed on both sides, or on the surface of the friction disk and the armature on the lining holder side. The electromagnet has a yoke on the armature side having an inner circular end face and an outer circular end face centered on the central axis, The lining holder, the armature, and the yoke are made of a magnetic material. The lining holder has a protrusion that projects toward the inner circumferential annular end face at a position opposite to the inner circumferential annular end face of the yoke, The electromagnetic brake device is characterized in that both the protrusion and the armature have a region that overlaps with the inner circumferential annular end face of the yoke when viewed from a direction along the rotation axis.

2. The electromagnetic brake device according to claim 1, characterized in that when the radial length of the inner circumferential annular end face is a, and the radial length of the region where the armature and the inner circumferential annular end face of the yoke overlap is J, the condition 0.25 ≤ J / a ≤ 0.8 is satisfied.

3. The electromagnetic brake device according to claim 1 or 2, characterized in that when the radial length of the inner circumferential annular end face is a and the radial length of the protrusion is b, the condition 0.25 ≤ b / a ≤ 0.75 is satisfied.

4. The electromagnetic brake device according to claim 1 or 2, characterized in that a stopper is provided to prevent the lining holder, which is attracted by the magnetic force, from coming into contact with the lining, the armature, or the yoke.

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