JP2007151369A - Eddy current-type reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eddy current-type reduction gear where magnetic short-circuit of a permanent magnet can be suppressed, when the permanent magnet of a magneto ring is made to be comparatively thin. <P>SOLUTION: The eddy current-type reduction gear includes a braking rotor 1, fitted to a rotation axis and the magneto ring 6 arranged so as to face the braking rotor 1. The magneto ring 6 includes a plurality of permanent magnets 8, which are arranged in a circumferential direction by leaving prescribed intervals and in which the magnetic poles are formed on a braking rotor 1-side and a side opposite to the braking rotor 1, and with a magnetic member 9 coupling the magnetic poles directed to a side opposite to the braking rotor 1 among the magnetic poles of the permanent magnets 8. Eddy current is caused in the braking rotor 1, and the rotation axis is slowed down and braked by supplying magnetism from the permanent magnet 8 to the braking rotor 1. A groove 11 is arranged in a face 10, facing the braking rotor 1 of the permanent magnet 6, by making it position in between the permanent magnets 8 in the circumferential direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an eddy current type reduction device that assists a friction brake of a vehicle, and more particularly to an eddy current type reduction device that uses a permanent magnet as a magnetic source.

  As an eddy current type speed reducer using a permanent magnet as a magnetic source, those described in Patent Documents 1 to 4 are known.

  For example, as shown in FIGS. 8 and 9, an eddy current reduction device using a permanent magnet as a magnetic source includes a drum-shaped braking rotor 41 attached to a rotating shaft (not shown) and a fixed system (not shown). And a stator 42 (magnetic force source) disposed inside the brake rotor 41. The stator 42 includes a magnet ring 43 provided so as to be rotatable in the circumferential direction, a magnetic ring 44 interposed between the brake rotor 41 and the magnet ring 43, and an actuator (not shown) that rotates the magnet ring 43. )).

  The magnet ring 43 includes an annular magnetic member 45 made of a magnetic material and a plurality of permanent magnets 46 attached to the outer peripheral surface of the magnetic member 45 at a predetermined interval in the circumferential direction. Each permanent magnet 46 has magnetic poles at both ends in the radial direction, and the magnetic poles facing the braking rotor 41 side are alternately reversed and aligned.

  The magnetic ring 44 includes an annular magnetic member 47 made of a magnetic material and a plurality of permanent magnets 48 embedded in the magnetic member 47 at a predetermined interval. Each permanent magnet 48 has magnetic poles at both ends in the circumferential direction, and the magnetic poles facing in the circumferential direction are set to have the same polarity.

  When decelerating and braking the rotating shaft (when braking is ON), as shown in FIG. 8, the magnetic poles facing the braking rotor 41 are between the permanent magnets 48 of the magnetic rings 44 adjacent in the circumferential direction. The magnet ring 43 is rotated by the actuator so that the permanent magnet 46 of the magnet ring 43 having the same polarity as the magnetic poles 48 is positioned (braking position). Then, a magnetic circuit W31 that connects the N pole and the S pole is formed between the permanent magnet 46 of the magnet ring 43 and the brake rotor 41, and N between the permanent magnet 48 of the magnetic ring 44 and the brake rotor 41 is formed. A magnetic circuit W32 connecting the pole and the S pole is formed. By these magnetic circuits W31 and W32, an eddy current is generated in the braking rotor 41, and the rotating shaft is decelerated and braked.

  On the other hand, when releasing deceleration braking (when braking is OFF), as shown in FIG. 9, the magnetic poles facing the braking rotor 41 between the permanent magnets 48 of the magnetic rings 44 adjacent in the circumferential direction are permanent magnets of the magnetic ring 44. The magnet ring 43 is rotated by the actuator so that the permanent magnet 46 of the magnet ring 43 that is different from the magnetic poles 48 is positioned (non-braking position). Then, a short-circuited magnetic circuit W33 (blocking circuit for the braking rotor 41) connecting the N pole and the S pole is formed between the permanent magnet 46 of the magnet ring 43 and the permanent magnet 48 of the magnetic ring 44, and the rotation shaft Deceleration braking is released.

Japanese Patent Publication No. 6-14782 Japanese Patent Publication No. 6-83571 Japanese Patent Publication No.7-118901 JP 2004-32927 A

  By the way, in the eddy current type reduction gear shown in FIG. 8 and FIG. 9, the weight (volume) of the eddy current type reduction gear can be reduced by reducing the volume of the permanent magnet 46 of the magnet ring 43. Is possible.

  That is, the thickness (see reference symbol T in FIG. 3), circumferential length (see reference symbol L in FIG. 3) or width (see reference symbol W in FIG. 3) or width (see reference symbol W in FIG. 3) of the magnet ring 43 is made thin (short). Thus, weight reduction and cost reduction of the eddy current type reduction gear can be achieved.

  However, if the circumferential length or width of the permanent magnet 46 of the magnet ring 43 is shortened, the area of the magnetic pole of the permanent magnet 46 (that is, the area where the magnetic flux lines come out) becomes small, and the flow of magnetic flux becomes insufficient. The improvement (or maintenance) of the braking performance of the eddy current type reduction gear cannot be expected.

  Therefore, in order to reduce the weight and reduce the cost without degrading the braking performance of the eddy current type speed reducer, the magnetic pole area of the permanent magnet 46 of the magnet ring 43, that is, the circumferential length and width of the permanent magnet 46 is set. It is effective to reduce only the thickness of the permanent magnet 46 without changing it.

  However, as shown in FIG. 10, if the thickness of the permanent magnet 46 of the magnet ring 43 is simply made relatively thin, the distance between the N pole and the S pole is shortened, and a part of the magnetism from the N pole to the S pole is obtained. May be short-circuited through the magnetic member 45 (see S2 in FIG. 10), and the braking performance of the eddy current type reduction gear may be reduced.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an eddy current type speed reducer that can suppress a magnetic short circuit of a permanent magnet when the thickness of the permanent magnet of the magnet ring is relatively thin.

  In order to achieve the above object, an invention according to claim 1 includes a braking rotor attached to a rotating shaft and a magnet ring disposed so as to face the braking rotor, and the magnet ring is arranged in a circumferential direction. A plurality of permanent magnets arranged at predetermined intervals and having magnetic poles formed on the braking rotor side and the opposite side of the braking rotor, and a magnetic pole facing the opposite side of the braking rotor among the magnetic poles of the permanent magnets In an eddy current type reduction device that includes a magnetic member that connects each other and supplies the magnetism from the permanent magnet to the braking rotor, thereby generating an eddy current in the braking rotor and decelerating and braking the rotating shaft. An eddy current type speed reducer characterized in that a groove is provided on a surface of the magnet ring facing the brake rotor so as to be positioned between the permanent magnets adjacent in the circumferential direction.

  A second aspect of the present invention is the eddy current reduction device according to the first aspect, wherein the groove is provided on the entire facing surface located between the permanent magnets adjacent in the circumferential direction.

  According to the present invention, when the permanent magnet of the magnet ring is formed to be relatively thin, the magnetic short of the permanent magnet can be suppressed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a partial front sectional view showing a state of braking of an eddy current reduction device according to an embodiment of the present invention. FIG. 2 is a partial front cross-sectional view showing the eddy current type reduction gear according to the embodiment of FIG.

  As shown in FIGS. 1 and 2, a drum-shaped braking rotor (braking drum) 1 in which eddy current is generated is attached to a rotating shaft (not shown) such as an output shaft of the transmission. The brake rotor 1 is made of a conductive material and a magnetic material (ferromagnetic material, soft magnetic material, etc., the same applies hereinafter) (for example, low carbon steel, cast iron, etc., the same applies hereinafter). On the outer peripheral surface of the brake rotor 1, there are provided heat radiating fins 2 for radiating heat generated by the eddy current.

  A stator 3 attached to a stationary system (not shown) such as a casing of the transmission is disposed inside (inward in the radial direction) of the braking rotor 1. The stator 3 is supported by a fixed system, and is disposed opposite to the hollow annular casing 4 made of a non-magnetic material (for example, a low magnetic permeability material such as aluminum, the same applies hereinafter) and the braking rotor 1. Is disposed between the magnet ring 6 and the brake rotor 1, and is provided integrally with the outer periphery of the casing 4. The ring 7 and an actuator (not shown) for rotating the magnet ring 6 are included.

  As shown in FIGS. 1 to 3, the magnet ring 6 is arranged at a predetermined interval in the circumferential direction of the braking rotor 1, and the magnetic pole is on the braking rotor 1 side (radially outer side) and the opposite side of the braking rotor 1 ( A plurality of permanent magnets 8 formed on the inner side in the radial direction), and magnetic poles of the permanent magnets 8 that are directed to the opposite side of the braking rotor 1 are connected to each other, and a magnetic member 9 made of a magnetic material is used. It is configured. That is, the permanent magnet 8 of the magnet ring 6 has magnetic poles formed at both ends in the radial direction. In the present embodiment, the magnetic member 9 of the magnet ring 6 is formed in an annular shape, and each permanent magnet 8 is attached to the facing surface 10 (the outer peripheral surface in the present embodiment) facing the braking rotor 1 of the magnetic member 9. ing. In the present embodiment, each permanent magnet 8 is set such that the magnetic poles facing the braking rotor 1 are alternately reversed in the circumferential direction.

  The permanent magnet 8 of the magnet ring 6 of this embodiment is formed so that its width W (see FIG. 3) is substantially equal to the width of the magnetic member 9.

  Here, the permanent magnet 8 of the magnet ring 6 of the present embodiment has a thickness T (see FIG. 3) compared to the thickness of the permanent magnet 46 used in the eddy current type speed reducer shown in FIGS. It is formed to be thin.

  Further, the permanent magnet 8 of the magnet ring 6 of the present embodiment has a circumferential length L and a width W (see FIG. 3) of the permanent magnet 46 used in the eddy current type speed reducer shown in FIGS. It is formed so as to be approximately equal to the circumferential length and width. That is, the permanent magnet 8 of the magnet ring 6 of the present embodiment is formed so that the area of the magnetic pole is substantially equal to the area of the magnetic pole of the permanent magnet 46 used in the eddy current type speed reducer shown in FIGS. Has been.

  Furthermore, the permanent magnet 8 of the magnet ring 6 of the present embodiment is set so that its coercive force is larger than the coercive force of the permanent magnet 46 used in the eddy current type speed reducer shown in FIGS. ing. When the thickness T of the permanent magnet 8 is relatively thin, if a permanent magnet 8 having a strong coercive force is used, a strong magnetic force can be obtained even if the thickness T of the permanent magnet 8 is relatively thin. It is possible to improve (or maintain) the braking performance of the eddy current type reduction gear.

  On a facing surface 10 (outer peripheral surface) of the magnet ring 6 (magnetic member 9) facing the braking rotor 1, a groove 11 having a predetermined depth is positioned between the permanent magnets 8 of the magnet ring 6 adjacent in the circumferential direction. It is provided along the axial direction. In this embodiment, each groove | channel 11 is provided in the opposing surface 10 whole of the magnet ring 6 adjacent in the circumferential direction. Each groove 11 is set so that the side surface 12 thereof is flush with the side surface 13 of the permanent magnet 8.

  As shown in FIGS. 1 and 2, the magnetic ring 7 is adjacent to the plurality of permanent magnets 14 having a predetermined interval in the circumferential direction and the magnetic poles facing the circumferential direction being set to the same polarity in the circumferential direction. It has a magnetic member 15 interposed between these permanent magnets 14 and made of a magnetic material. That is, the permanent magnet 14 of the magnetic ring 7 has magnetic poles formed at both ends in the circumferential direction. In the present embodiment, the magnetic member 15 of the magnetic ring 7 is formed in an annular shape, and each permanent magnet 14 is embedded in the magnetic member 15.

  In the present embodiment, the permanent magnets 8 of the magnet ring 6 and the permanent magnets 14 of the magnetic ring 7 are set to the same number. In the present embodiment, the permanent magnet 8 of the magnet ring 6 and the permanent magnet 14 of the magnetic ring 7 are made of rare earth such as neodymium.

  On the surface of the magnetic ring 7 (magnetic member 15) on the side of the magnet ring 6 (in the radial direction), that is, on the inner peripheral surface of the magnetic ring 7, it is positioned between each permanent magnet 14 of the magnetic ring 7 and the magnet ring 6. Thus, a plurality of grooves 16 are provided at predetermined intervals in the circumferential direction and along the axial direction. That is, each groove 16 is provided to be positioned on the radially inner side of the permanent magnet 14 embedded in the magnetic member 15 of the magnetic ring 7.

  On the inner peripheral surface of the magnetic ring 7 (magnetic member 15), a plurality of protrusions 17 that are partitioned by the grooves 16 and extend toward the magnet ring 6 are provided at predetermined intervals in the circumferential direction.

  The actuator switches the relative position between the magnet ring 6 and the magnetic ring 7 between a braking position and a non-braking position. The braking position of the present embodiment is such that the magnetic poles of the permanent magnets 14 and the radially outer magnetic poles facing the braking rotor 1 have the same polarity on the protrusions 17 between the permanent magnets 14 of the magnetic rings 7 adjacent in the circumferential direction. The permanent magnet 8 of the ring 6 is opposed (see FIG. 1). The non-braking position of the present embodiment is such that the relative position of the magnet ring 6 and the magnetic ring 7 is shifted from the braking position by a predetermined rotation width in the circumferential direction. The permanent magnets 8 of the magnet ring 6 in which the magnetic poles of the permanent magnets 14 and the magnetic poles on the radially outer side facing the braking rotor 1 are different from each other are opposed to the protrusions 17 between the permanent magnets 14 (FIG. 2). reference).

  Next, the operation of this embodiment will be described.

  When the brake is ON (when the rotating shaft is decelerated and braked), the magnet ring 6 is rotated by a predetermined width in the circumferential direction from the non-braking position by the actuator, and the relative position between the magnet ring 6 and the magnetic ring 7 is shown in FIG. Switch to the braking position shown in. At this time, a magnetic circuit W11 connecting the N pole and the S pole is formed between the permanent magnet 8 of the magnet ring 6 and the braking rotor 1, and between the permanent magnet 14 of the magnetic ring 7 and the braking rotor 1. A magnetic circuit W12 connecting the N pole and the S pole is formed. As a result, the magnetism from the permanent magnets 8 and 14 is supplied to the braking rotor 1, and an eddy current is generated in the braking rotor 1 to decelerate and brake the rotating shaft.

  Here, in the present embodiment, the groove 11 is provided on the facing surface 10 of the magnet ring 6 facing the braking rotor 1 so as to be positioned between the permanent magnets 8 adjacent in the circumferential direction. When the groove 11 is provided, the distance of the magnetic short (see reference numeral S1 in FIG. 4) when a part of magnetism is short-circuited from the N pole to the S pole through the magnetic member 9 does not provide the groove 11 (FIG. When the thickness T of the permanent magnet 8 of the magnet ring 6 is relatively thin, the magnetic short circuit can be suppressed. As a result of analysis, it was found that when the groove 11 was provided, the amount of magnetic short circuit was significantly different from that when the groove 11 was not provided.

  By providing the groove 11, the magnetic flux may flow to the side surface 12 of the groove 11 as indicated by reference numeral 18 in FIG. 4. However, as a result of the analysis, the magnetic flux flowing to the side surface 12 contributes to the braking performance of the eddy current reduction device. It was found to be so small that it had no effect.

  Moreover, in this embodiment, since the groove | channel 11 of the magnet ring 6 was provided in the opposing surface 10 whole of the magnet ring 6 located between the permanent magnets 8 adjacent to the circumferential direction, the magnetic short of the permanent magnet 8 is suppressed more effectively. can do.

  On the other hand, at the time of braking OFF (when releasing deceleration braking), the magnet ring 6 is rotated by a predetermined width in the circumferential direction from the braking position by the actuator, and the relative position between the magnet ring 6 and the magnetic ring 7 is shown in FIG. Switch to the non-braking position. At this time, a short-circuit magnetic circuit W13 (blocking circuit for the braking rotor 1) connecting the N pole and the S pole is formed between the permanent magnet 8 of the magnet ring 6 and the permanent magnet 14 of the magnetic ring 7, and the rotating shaft The deceleration braking is released.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various other embodiments can be adopted.

  For example, as shown in FIG. 5, a fixing member 20 made of a non-magnetic material is provided between permanent magnets 8 of magnet rings 6 adjacent in the circumferential direction via bolts 21 and the like. For example, each permanent magnet 8 may be fixed to the magnetic member 9.

  Further, the configuration of the magnetic ring 7 is not limited to the above-described embodiment. For example, as shown in FIGS. 6 and 7, a magnetic ring 30 is formed by connecting an arc-shaped pole piece 31 made of a magnetic material and non-magnetic members 32 made of a non-magnetic material alternately in the circumferential direction. It may be made.

  In the eddy current reduction device shown in FIGS. 6 and 7, the magnet ring 6 is rotated so that the circumferential positions of the permanent magnet 8 and the pole piece 31 are aligned, so that the permanent magnet 8 and the brake rotor 1 are positioned. A magnetic circuit W21 connecting the N pole and the S pole is formed, and an eddy current is generated in the braking rotor 1 to decelerate and brake the rotating shaft (see FIG. 6). On the other hand, by rotating the magnet ring 6 so that the permanent magnet 8 straddles between the pole pieces 31 adjacent in the circumferential direction, an N pole and an S pole are provided between the permanent magnet 8 and the pole piece 31. A short-circuiting magnetic circuit W22 to be connected (breaking circuit for the braking rotor 1) is formed to release the deceleration braking of the rotating shaft (see FIG. 7).

  In the above-described embodiment, the magnet ring 6 is rotated by the actuator. However, the present invention is not limited to this, and the magnetic ring 7 may be rotated instead of the magnet ring 6. The magnetic ring 7 may be rotated together.

  In the above-described embodiment, the stator 3 is disposed on the inner side (radially inner side) of the braking rotor 1. However, the present invention is not limited to this, and the stator is disposed on the outer side (radially outer side) of the braking rotor 1. 3 may be arranged.

  Furthermore, although the brake rotor 1 is formed in a drum shape in the above-described embodiment, the present invention is not limited to this, and the brake rotor 1 may be formed in a disk shape.

It is a partial front sectional view showing at the time of braking of an eddy current type reduction gear device concerning one embodiment of the present invention. It is a partial front sectional view showing the non-braking time of the eddy current type speed reducer according to the embodiment of FIG. It is a perspective view of a magnet ring. It is a partial front sectional view of a magnet ring. It is a partial front sectional view of a magnet ring showing a modification. It is a fragmentary front sectional view which shows the time of braking of the eddy current type reduction gear device which concerns on the modification of a magnetic ring. It is a fragmentary front sectional view which shows the time of non-braking of the eddy current type reduction gear device concerning the modification of a magnetic ring. It is a fragmentary front sectional view which shows the time of braking of the conventional eddy current type reduction gear. It is a fragmentary front sectional view which shows the time of non-braking of the conventional eddy current type reduction gear. It is a partial front sectional view of a magnet ring showing a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Braking rotor 6 Magnet ring 8 Permanent magnet 9 Magnetic member 10 Opposing surface 11 Groove

Claims (2)

A brake rotor attached to the rotating shaft; and a magnet ring disposed so as to face the brake rotor, the magnet ring being disposed at a predetermined interval in the circumferential direction, and a magnetic pole disposed on the brake rotor side. A plurality of permanent magnets formed on the opposite side of the braking rotor, and a magnetic member that connects magnetic poles of the permanent magnets facing toward the opposite side of the braking rotor. In the eddy current type speed reducer that decelerates and brakes the rotating shaft by generating an eddy current in the braking rotor by supplying the magnetism of
An eddy current reduction device, characterized in that a groove is provided on a surface of the magnet ring facing the brake rotor so as to be positioned between the permanent magnets adjacent in the circumferential direction.   2. The eddy current reduction device according to claim 1, wherein the groove is provided on the entire facing surface located between the permanent magnets adjacent in the circumferential direction.

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