Frictional engagement device

Abstract

To provide a frictional engagement device that enables energy saving.SOLUTION: A friction engagement device comprises an armature, a friction disc, a permanent electromagnet, and a support member. The armature is arranged so as to be movable in an axial direction. The friction disc is arranged so as to be rotatable relative to the armature. The friction disc faces the armature in the axial direction. The permanent electromagnet is configured to move the armature in the axial direction. The support member supports the permanent electromagnet.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a friction engagement device.

Background Art

[0002] As a friction engagement device such as a brake device or a clutch device, an electromagnetic brake or an electromagnetic clutch using electromagnetic force is widely used. For example, an excitation operation type electromagnetic brake is configured such that the brake operates while current is applied to a coil. Also, a non-excitation operation type electromagnetic brake is configured such that the brake operates when no current is applied to the coil (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described excitation operation type electromagnetic brake, it is necessary to apply current while the brake is operating, and in the non-excitation operation type electromagnetic brake, it is necessary to apply current while the brake is not operating. That is, it is necessary to apply current while the armature is attracted by the electromagnetic brake.

[0005] An object of the present invention is to provide a friction engagement device capable of power saving.

Means for Solving the Problems

[0006] The friction engagement device according to the first aspect includes an armature, a friction disk, a permanent magnet, and a support member. The armature is arranged to be movable in the axial direction. The friction disk is arranged to be relatively rotatable with respect to the armature. The friction disk faces the armature in the axial direction. The permanent magnet is configured to move the armature in the axial direction. The support member supports the permanent magnet.

[0007] According to this configuration, the permanent magnet is configured to move the armature in the axial direction. Here, the permanent magnet can move the armature in the axial direction by energizing only when switching between the adsorbed state and the non-adsorbed state, so power saving is possible.

[0008] The friction engagement device according to the second aspect is configured as follows in the friction engagement device according to the first aspect. The permanent magnet has a pair of yokes, a first magnet, a second magnet, and a coil. The pair of yokes are arranged at intervals from each other. The first magnet is arranged between the pair of yokes. The second magnet is arranged between the pair of yokes. The second magnet has a lower coercive force than the first magnet. The coil is wound around at least the second magnet. Note that the coil may be wound around both the first magnet and the second magnet.

[0009] The friction engagement device according to the third aspect is configured as follows in the friction engagement device according to the second aspect. The pair of yokes are arranged at intervals in the circumferential direction.

[0010] The friction engagement device according to the fourth aspect is configured as follows in the friction engagement device according to the second or third aspect. The first magnet and the second magnet are arranged in the radial direction.

[0011] The friction engagement device according to the fifth aspect is configured as follows in the friction engagement device according to any one of the second to fourth aspects. The friction engagement device includes a plurality of permanent magnets arranged in the circumferential direction. Each first magnet has a magnetization direction along the circumferential direction. In a pair of adjacent permanent magnets, each first magnet is arranged such that the magnetization directions are different from each other. That is, the magnetization directions of the first magnets are in directions facing each other or away from each other.

[0012] The friction engagement device according to the sixth aspect is configured as follows in the friction engagement device according to any one of the second to fifth aspects. The armature is arranged between the permanent magnet and the friction disk in the axial direction. The yoke protrudes from the support member in the axial direction.

[0013] The friction engagement device according to the seventh aspect further includes a biasing member in the friction engagement device according to any one of the first to sixth aspects. The biasing member biases the armature toward the friction disk in the axial direction. The armature is arranged between the permanent magnet and the friction disk in the axial direction.

[0014] The friction engagement device according to the eighth aspect is configured as follows in the friction engagement device according to the seventh aspect. The friction engagement device includes a plurality of permanent magnets arranged in the circumferential direction. The biasing member is arranged between a pair of adjacent permanent magnets in the circumferential direction.

[0015] The friction engagement device according to the ninth aspect is configured as follows in the friction engagement device according to the seventh or eighth aspect. The support member has a first accommodation recess and a second accommodation recess. The first accommodation recesses are arranged at intervals in the circumferential direction. The second accommodation recess is arranged between the first accommodation recesses in the circumferential direction. The permanent magnet is arranged in the first accommodation recess. The biasing member is arranged in the second accommodation recess.

[0016] The friction engagement device according to the tenth aspect further includes a non-magnetic friction material and a magnetic friction material in the friction engagement device according to any one of the second to sixth aspects. The non-magnetic friction material is attached to the friction disk. The magnetic friction material is attached to the tip surface of the yoke. The friction disk is disposed between the permanent magnet and the armature in the axial direction. The friction disk has a through hole extending in the axial direction. The yoke is exposed toward the armature through the through hole.

[0017] The friction engagement device according to the eleventh aspect further includes a biasing member in the friction engagement device according to any one of the first to tenth aspects. The biasing member biases the armature away from the friction disk in the axial direction. The friction disk is disposed between the permanent magnet and the armature in the axial direction.

[0018] The friction engagement device according to the twelfth aspect is configured as follows in the friction engagement device according to any one of the first to eleventh aspects. The armature and the friction disk are rotatably disposed.

[0019] The friction engagement device according to the thirteenth aspect is configured as follows in the friction engagement device according to the twelfth aspect. The permanent magnet is disposed radially outside the friction disk. The permanent magnet is disposed on the same side as the friction disk with respect to the armature in the axial direction.

[0020] The friction engagement device according to the fourteenth aspect is configured as follows in the friction engagement device according to any one of the first to thirteenth aspects. The friction disk has a boss portion and a disk body portion. The disk body portion is disposed radially outside the boss portion. The disk body portion is movably attached to the boss portion in the axial direction.

Advantages of the Invention

[0021] According to the present invention, power saving is possible.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0023] Hereinafter, the friction engagement device 100 according to the present embodiment will be described with reference to the drawings. In the following description, the axial direction is the direction in which the rotation axis O of the friction engagement device 100 extends. Also, the circumference is the circumference of a circle centered on the rotation axis, and the diameter is the diameter of a circle centered on the rotation axis.

[0024] <Friction Engagement Device> As shown in FIGS. 1 and 2, the friction engagement device 100 includes an armature 2, a friction disk 3, a plurality of permanent magnets 4, a support member 5, side plates 6, a plurality of biasing members 7, and a plurality of collars 8. In the present embodiment, the friction engagement device 100 is used as a brake device.

[0025] <Armature> The armature 2 is disc-shaped. The armature 2 has a plurality of notch portions 21 on the outer peripheral portion. The respective notch portions 21 are arranged at intervals in the circumferential direction. Each notch portion 21 opens radially outward.

[0026] The armature 2 is arranged to be axially movable. Specifically, the armature 2 moves towards the friction disk 3 or moves away from the friction disk 3. The armature 2 is arranged to be non-rotatable. Specifically, the armature 2 is arranged to be non-rotatable with respect to the support member 5. The armature 2 is arranged axially between the friction disk 3 and the permanent magnet 4.

[0027] The armature 2 is made of a magnetic material. Specifically, the armature 2 is made of steel. More specifically, the armature 2 is made of carbon steel for machine structures (e.g., S45C), hot-rolled steel for general structures (e.g., SS400), or cold-rolled steel (e.g., SPCC), etc.

[0028] <Friction disk> The friction disk 3 is disc-shaped. The friction disk 3 is arranged to be rotatable. That is, the friction disk 3 is arranged to be relatively rotatable with respect to the armature 2. The friction disk 3 is configured to rotate together with a rotating member (not shown) to be braked. The friction disk 3 faces the armature 2 axially.

[0029] The friction disk 3 is made of a non-magnetic material. Specifically, the friction disk 3 is made of stainless steel. More specifically, the friction disk 3 is made of austenitic stainless steel (e.g., SUS303, SUS304, SUS316), etc.

[0030] The friction disk 3 has a boss portion 31 and a disk body portion 32. The boss portion 31 is cylindrical. The rotating member fits into the boss portion 31. For example, the rotating member fits into the boss portion 31 and rotates integrally with the boss portion 31 by a key and a keyway.

[0031] The disk main body 32 is disposed radially outward with respect to the boss portion 31. The disk main body 32 is attached to the boss portion 31 so as to be axially movable. Specifically, the boss portion 31 is spline-fitted to the disk main body 32. Therefore, the disk main body 32 rotates integrally with the boss portion 31 and is axially movable with respect to the boss portion 31.

[0032] <Support member> FIG. 3 is a plan view of the friction engagement device 100 with the armature 2, the friction disk 3, and the side plate 6 removed. As shown in FIGS. 2 and 3, the support member 5 supports the permanent magnet 4. Specifically, the support member 5 has a plurality of first accommodation recesses 51 and a plurality of second accommodation recesses 52. The support member 5 supports the permanent magnet 4 by accommodating the permanent magnet 4 in the first accommodation recess 51. Further, the support member 5 supports the biasing member 7 by accommodating the biasing member 7 in the second accommodation recess 52.

[0033] The first accommodation recesses 51 are arranged at intervals in the circumferential direction. The second accommodation recess 52 is arranged between a pair of adjacent first accommodation recesses 51 in the circumferential direction. In the present embodiment, the plurality of first accommodation recesses 51 and the plurality of second accommodation recesses 52 are alternately arranged in the circumferential direction.

[0034] The first accommodation recess 51 opens axially toward the armature 2. Further, the first accommodation recess 51 also opens radially inward. The second accommodation recess 52 opens axially toward the armature 2.

[0035] The support member 5 is fixed to a fixed member. The fixed member is a member that does not move easily, such as a vehicle body frame, for example. The support member 5 is fixed to the fixed member by bolts 13. For this reason, the support member 5 is non-rotatable. Further, the support member 5 is non-axially movable.

[0036] The support member 5 is made of a non-magnetic material. For example, the support member 5 is made of stainless steel, aluminum, or an aluminum alloy, etc.

[0037] <Side plate> As shown in FIG. 2, the side plate 6 is arranged at a distance from the support member 5 in the axial direction. The armature 2 and the friction disk 3 are arranged between the side plate 6 and the support member 5 in the axial direction.

[0038] The side plate 6 is disc-shaped. The side plate 6 is fixed to the support member 5. For example, the side plate 6 is fixed to the support member 5 by a plurality of bolts 9. Therefore, the side plate 6 is non-rotatable relative to the support member 5 and non-movable in the axial direction.

[0039] The side plate 6 is made of a magnetic material. Specifically, the side plate 6 is made of steel. More specifically, the side plate 6 is made of carbon steel for mechanical structures (e.g., S45C), hot-rolled steel for general structures (e.g., SS400), or cold-rolled steel (e.g., SPCC), etc. Note that the side plate 6 may be made of a non-magnetic material. In this case, the side plate 6 can be made of stainless steel. Specifically, the friction disk 3 can be made of austenitic stainless steel (e.g., SUS303, SUS304, SUS316), etc.

[0040] <Collor> The collor 8 is arranged between the side plate 6 and the support member 5 in the axial direction. The collor 8 is cylindrical. The bolt 9 extends through the collor 8. The distance between the side plate 6 and the support member 5 is maintained by this collor 8. Also, the collor 8 is arranged within the notch 21 of the armature 2. Therefore, the armature 2 is non-rotatable due to interference with the collor 8.

[0041] <Biasing member> As shown in FIGS. 2 and 3, the biasing member 7 biases the armature 2 toward the friction disk 3 in the axial direction. The biasing member 7 is, for example, a coil spring. The biasing member 7 is disposed between a pair of permanent magnets 4 adjacent to each other in the circumferential direction. Specifically, the biasing member 7 is disposed in the second accommodation recess 52 of the support member 5. A part of the biasing member 7 protrudes from the second accommodation recess 52 toward the armature 2.

[0042] The biasing member 7 is disposed radially inward with respect to the bolt 9 for fixing the side plate 6 and the bolt 13 for fixing the support member 5. In a radial view, the biasing member 7 overlaps with the bolt 9 or the bolt 13.

[0043] The biasing member 7 is preferably made of a magnetic material. Note that the biasing member 7 may be made of a non-magnetic material.

[0044] <Permanent magnet> The permanent magnet 4 is configured to move the armature 2 in the axial direction. The permanent magnet 4 switches between an adsorbed state and a non-adsorbed state. That is, by applying a signal from the outside, the permanent magnet 4 can be set to the adsorbed state or the non-adsorbed state. The permanent magnet 4 is configured to adsorb the armature 2 and move it in the axial direction when in the adsorbed state. In the present embodiment, the permanent magnet 4 moves the armature 2 away from the friction disk 3 in the axial direction.

[0045] The permanent magnets 4 are arranged in the circumferential direction. The permanent magnets 4 are disposed in the first accommodation recess 51 of the support member 5.

[0046] The permanent magnet 4 includes a first magnet 41, a second magnet 42, a pair of yokes 43, and a coil 44. The pair of yokes 43 are arranged at intervals from each other. Specifically, the pair of yokes 43 are arranged at intervals from each other in the circumferential direction. Each yoke 43 is plate-shaped. Each yoke 43 is arranged so as to face the circumferential direction.

[0047] The yoke 43 protrudes axially from the support member 5 toward the armature 2. Although not particularly limited, the protruding amount of the yoke 43 from the support member 5 is, for example, about 0.1 to 0.2 mm. Note that the yoke 43 may not protrude from the support member 5 and may be flush with the support member 5.

[0048] The yoke 43 protrudes radially inward from the first housing recess 51. Although not particularly limited, the protruding amount of the yoke 43 from the first housing recess 51 is, for example, about 2 to 3 mm. Note that the yoke 43 may not protrude radially inward from the first housing recess 51.

[0049] The yoke 43 is made of a magnetic material. The yoke 43 is made of, for example, steel. More specifically, the yoke 43 is made of carbon steel for machine structural use (for example, S45C, S50C), or hot-rolled steel for general structure (for example, SS400), etc.

[0050] The first magnet 41 is disposed between the pair of yokes 43. The first magnet 41 is in contact with each yoke 43. The first magnet 41 has a larger coercive force than the second magnet 42. The first magnet 41 is configured not to reverse magnetization even when a pulse current is passed through the coil 44. The first magnet 41 is, for example, a neodymium magnet, or a samarium cobalt magnet, etc.

[0051] The magnetization direction of the first magnet 41 is along the circumferential direction. That is, the magnetization direction of the first magnet 41 is from one yoke 43 of the pair of yokes 43 toward the other yoke 43. In a pair of adjacent permanent electromagnets 4, the first magnets 41 are arranged such that the magnetization directions are different from each other. For example, in one first magnet 41, the pole on the side closer to the other first magnet 41 is the N pole, and in the other first magnet 41, the pole on the side closer to the one first magnet 41 is the N pole. By arranging them in this way, it is possible to suppress the flow of magnetic flux between a pair of adjacent permanent electromagnets 4.

[0052] The second magnet 42 is disposed between a pair of yokes 43. The second magnet 42 is in contact with each yoke 43. The second magnet 42 has a lower coercive force than the first magnet 41. The second magnet 42 is configured to reverse its magnetization by passing a pulsed current through the coil 44. The second magnet 42 is, for example, an alnico magnet or the like.

[0053] The first magnet 41 and the second magnet 42 are arranged in the radial direction. In the present embodiment, the first magnet 41 is disposed radially inside the second magnet 42. Note that the first magnet 41 may be disposed radially outside the second magnet 42.

[0054] The coil 44 is wound around the first magnet 41 and the second magnet 42. Note that the coil 44 may be wound only around the second magnet 42 and not around the first magnet 41. The coil 44 is disposed between the pair of yokes 43.

[0055] The coil 44 is completely accommodated within the first accommodation recess 51 in the axial direction. On the other hand, in the radial direction, the coil 44 protrudes radially inward from the first accommodation recess 51. Note that the coil 44 may be completely accommodated within the first accommodation recess 51 in the radial direction.

[0056] The coil 44 is connected to an external power source. The coil 44 is configured to reverse the magnetization of the second magnet 42 by passing a pulsed current through the coil 44. Note that the magnetization of the first magnet 41 does not reverse even when a pulsed current is passed through the coil 44.

[0057] <Operation> The friction engagement device 100 configured as described above operates as follows. First, in the permanent magnet 4, when the magnetization direction of the first magnet 41 is different from the magnetization direction of the second magnet 42, a magnetic circuit is formed among the pair of yokes 43, the first magnet 41, and the second magnet 42. For this reason, the permanent magnet 4 is in a non-adsorbed state.

[0058] When the permanent magnet 4 is in a non-adsorbing state, the armature 2 is pressed against the friction disk 3 by the biasing force of the biasing member 7. As a result, the friction disk 3 is sandwiched between the armature 2 and the side plate 6, and rotation is stopped.

[0059] Next, a pulse current is passed through the coil 44 of the permanent magnet 4 to magnetically reverse the second magnet 42 and make the magnetization direction of the second magnet 42 the same as that of the first magnet 41, whereby the permanent magnet 4 enters an adsorbing state. That is, a magnetic circuit is formed among the pair of yokes 43, the first magnet 41, the second magnet 42, and the armature 2. As a result, the armature 2 moves axially away from the friction disk 3 against the biasing force of the biasing member 7. Since the sandwiching of the friction disk 3 between the armature 2 and the side plate 6 is released, the friction disk 3 becomes rotatable. Note that after magnetically reversing the second magnet 42, it is not necessary to pass a current through the coil 44. That is, no power is consumed while the armature 2 is adsorbed by the permanent magnet 4.

[0060] Next, a pulse current is passed through the coil 44 of the permanent magnet 4 in the direction opposite to the above to magnetically reverse the second magnet 42 and make the magnetization direction of the second magnet 42 opposite to that of the first magnet 41, whereby the permanent magnet 4 enters a non-adsorbing state. That is, a magnetic circuit is formed within the first magnet 41, the second magnet 42, and the pair of yokes 43, and no magnetic flux flows to the armature 2. Since the armature 2 is not adsorbed by the permanent magnet 4, the armature 2 moves toward the friction disk 3 side by the biasing force of the biasing member 7. As a result, the friction disk 3 is sandwiched between the armature 2 and the side plate 6 and becomes non-rotatable. Also in this case, it is not necessary to pass a current through the coil 44 after magnetically reversing the second magnet 42.

[0061] [Modification Example] The embodiments of the present invention have been described above, but the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention. Note that the following modification examples can basically be applied simultaneously.

[0062] (a) In the above-described embodiment, the armature 2 is configured to be separated from the friction disk 3 by adsorbing the armature 2 with the permanent magnet 4, but the configuration of the friction engagement device 100 is not limited to this.

[0063] For example, as shown in FIG. 4, the friction engagement device 100 may be configured to press the armature 2 against the friction disk 3 by adsorbing the armature 2 with the permanent magnet 4. Hereinafter, this modification will be described in detail. Note that the description of substantially the same configuration as that of the above-described embodiment will be omitted.

[0064] The armature 2 is rotatably arranged. A rotating member 101 to be braked is attached to the armature 2. The armature 2 rotates integrally with the rotating member 101. The biasing member 7 is arranged between the armature 2 and the rotating member 101. The biasing member 7 is attached to the armature 2 and the rotating member 101. The biasing member 7 biases the armature 2 to be separated from the friction disk 3 in the axial direction. For example, the biasing member 7 is a leaf spring or the like.

[0065] The friction disk 3 is arranged non-rotatably. Specifically, the friction disk 3 is fixed to the support member 5. For example, the friction disk 3 is fixed to the support member 5 by bolts or the like. Note that the friction disk 3 may be integrally formed with the support member 5 by one member.

[0066] The armature 2 is arranged between the rotating member 101 and the friction disk 3 in the axial direction. The friction disk 3 is arranged between the armature 2 and the permanent magnet 4 in the axial direction.

[0067] FIG. 5 is a plan view of the friction engagement device 100 with the rotating member 101, the biasing member 7, and the armature 2 removed. As shown in FIG. 5, the friction disk 3 has a plurality of through holes 33 extending in the axial direction.

[0068] A pair of yokes 43 of the permanent magnet 4 extends within the through-hole 33 of the friction disk 3. The tip surface (the upper end surface in FIG. 4) of each yoke 43 is exposed toward the armature 2 through the through-hole 33.

[0069] A non-magnetic friction material 11a is attached to the upper surface of the friction disk 3 (the surface facing the armature 2). For example, the non-magnetic friction material 11a is attached to the friction disk 3 by an adhesive or the like. The non-magnetic friction material 11a is a friction material having no magnetism.

[0070] A magnetic friction material 11b is attached to the tip surface of the yoke 43 (the surface facing the armature 2). For example, the magnetic friction material 11b is attached to the yoke 43 by an adhesive or the like. The magnetic friction material 11b is a friction material having magnetism.

[0071] In the friction engagement device 100 configured as described above, when the permanent magnet 4 is in a non-adsorbed state, the armature 2 is separated from the friction disk 3 by the biasing force of the biasing member 7, so the armature 2 is rotatable. On the other hand, when the permanent magnet 4 is in an adsorbed state, the armature 2 is pressed against the friction disk 3 and thus becomes non-rotatable. Also in this case, after magnetizing and inverting the second magnet 42, it is not necessary to pass a current through the coil 44. That is, while the armature 2 is adsorbed by the permanent magnet 4, no power is consumed.

[0072] (b) In the above embodiment, the friction engagement device 100 has been described as a brake device, but the friction engagement device 100 can also be used as a clutch device. Hereinafter, this modification will be described in detail. Note that the description of substantially the same configuration as that of the above embodiment will be omitted.

[0073] As shown in FIG. 6, in the axial direction, the armature 2 is disposed between the permanent magnet 4 and the first rotating member 101. The permanent magnet 4 is disposed radially outside with respect to the friction disk 3. The permanent magnet 4 faces the armature 2 in the axial direction.

[0074] The armature 2 is rotatably arranged. A first rotating member 101 is attached to the armature 2, and the armature 2 and the first rotating member 101 rotate integrally.

[0075] The biasing member 7 is arranged between the armature 2 and the first rotating member 101. The biasing member 7 is attached to the armature 2 and the first rotating member 101. The biasing member 7 biases the armature 2 to separate from the friction disk 3 in the axial direction. For example, the biasing member 7 is a leaf spring or the like.

[0076] The friction disk 3 is rotatably arranged. A second rotating member 102 is attached to the friction disk 3.

[0077] The permanent magnet 4 is arranged on the same side as the friction disk 3 with respect to the armature 2 in the axial direction. That is, as shown in FIG. 6, the permanent magnet 4 and the friction disk 3 are arranged below the armature 2.

[0078] In the friction engagement device 100 configured as described above, when the permanent magnet 4 is in a non-adsorbed state, the armature 2 is separated from the friction disk 3 by the biasing member 7, so torque is not transmitted between the armature 2 and the friction disk 3. That is, torque transmission between the first rotating member 101 and the second rotating member 102 is blocked. On the other hand, when the permanent magnet 4 is in an adsorbed state, the armature 2 is pressed against the friction disk 3, so the armature 2 and the friction disk 3 rotate integrally. That is, torque is transmitted between the armature 2 and the friction disk 3. Therefore, torque is transmitted between the first rotating member 101 and the second rotating member 102.

[0079] As described above, the friction engagement device 100 according to this modification can cut off torque transmission between the armature 2 and the friction disk 3 by setting the state of the permanent magnet 4 to the non-adsorbed state, and can transmit torque between the armature 2 and the friction disk 3 by setting the state of the permanent magnet 4 to the adsorbed state. That is, the friction engagement device 100 can be used as a clutch device. Also in this case, after inverting the magnetization of the second magnet 42, it is not necessary to flow a current through the coil 44. That is, no power is consumed while the armature 2 is attracted by the permanent magnet 4.

[0080] In this modification, as shown in FIG. 7, the pair of yokes 43 of the permanent magnet 4 may have protrusions 431. The protrusions 431 protrude toward the armature 2 at the outer peripheral portion. Thereby, since the friction disk 3 can be disposed above the yoke 43 excluding the protrusions 431, the diameter of the friction disk 3 can be increased. As a result, the contact area between the armature 2 and the friction disk 3 can be increased.

[0081] Note that the friction engagement device 100 may be configured to cut off torque transmission between the armature 2 and the friction disk 3 by setting the state of the permanent magnet 4 to the adsorbed state, and to transmit torque between the armature 2 and the friction disk 3 by setting the state of the permanent magnet 4 to the non-adsorbed state. In this case, the axial positions of the armature 2 and the friction disk 3 are interchanged. Also, the biasing member 7 biases the armature 2 so as to press it toward the friction disk 3.

[0082] (c) The friction engagement device 100 according to the above-described embodiment or the friction engagement device 100 according to the modification (a) can also be attached to a motor. That is, the friction engagement device 100 can be used as a brake of a motor with a brake.

Description of Reference Numerals

[0083] 2: Armature 3: Friction disk 31: Boss portion 32: Disk main body 4: Permanent magnet 41: First magnet 42: Second magnet 43: Yoke 44: Coil 5: Support member 51: First housing recess 52: Second housing recess 7: Biasing member 11a: Non-magnetic friction material 11b: Magnetic friction material 100: Friction engagement device

Claims

1. An armature arranged to be axially movable; A friction disk arranged to be relatively rotatable with respect to the armature and facing the armature in the axial direction; A permanent magnet configured to axially move the armature; A support member for supporting the permanent magnet; A friction engagement device comprising the above.

2. The permanent magnet includes: A pair of yokes arranged at intervals from each other; A first magnet arranged between the pair of yokes; A second magnet arranged between the pair of yokes and having a lower coercive force than the first magnet; A coil wound around at least the second magnet; and has: The friction engagement device according to Claim 1.

3. The pair of yokes are arranged at intervals in the circumferential direction. The friction engagement device according to Claim 2.

4. The first magnet and the second magnet are arranged in the radial direction. The friction engagement device according to Claim 2.

5. The friction engagement device includes a plurality of the permanent magnets arranged in the circumferential direction, each of the first magnets has a magnetization direction along the circumferential direction, and in a pair of adjacent permanent magnets, each first magnet is arranged such that the magnetization directions are different from each other. The friction engagement device according to Claim 2.

6. The armature is arranged between the permanent magnet and the friction disk in the axial direction, and the yoke projects from the support member in the axial direction. The friction engagement device according to Claim 2.

7. The friction engagement device further includes a biasing member that biases the armature toward the friction disk in the axial direction, and the armature is arranged between the permanent magnet and the friction disk in the axial direction. The friction engagement device according to Claim 1.

8. The friction engagement device includes a plurality of the permanent magnets arranged in the circumferential direction, and the biasing member is arranged between a pair of adjacent permanent magnets in the circumferential direction. The friction engagement device according to Claim 7.

9. The support member has a first accommodation recess arranged at intervals in the circumferential direction and a second accommodation recess arranged between the first accommodation recesses in the circumferential direction, the permanent magnet is arranged in the first accommodation recess, and the biasing member is arranged in the second accommodation recess. The friction engagement device according to Claim 7.

10. A non-magnetic friction material attached to the friction disk; A magnetic friction material attached to the tip surface of the yoke; and further includes: The friction disk is disposed axially between the permanent magnet and the armature. The friction disk has a through hole extending axially. The yoke is exposed toward the armature through the through hole. The friction engagement device according to claim 2.

11. Further provided is a biasing member that biases the armature away from the friction disk in the axial direction. The friction disk is disposed axially between the permanent magnet and the armature. The friction engagement device according to claim 1.

12. The armature and the friction disk are rotatably disposed. The friction engagement device according to claim 1.

13. The permanent magnet is disposed radially outside the friction disk. The permanent magnet is disposed on the same side as the friction disk with respect to the armature axially. The friction engagement device according to claim 12.

14. The friction disk has a boss portion and a disk body portion disposed radially outside the boss portion. The disk body portion is axially movably attached to the boss portion. The friction engagement device according to claim 1.

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