JP2000245134A - Eddy current decelerating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eddy current decelerating apparatus, whose thick part equivalent to a conventional ferromagnetic plate is integrally formed to a guide tube formed out of a soft magnetic body or ferromagnetic body, and which can be manufactured easily at a low cost. SOLUTION: This eddy current decelerating apparatus is provided with a nonmagnetic guide tube 5, which is disposed between a pair of braking discs 3 connected to a rotating shaft 2 and attached to the nonrotating part of a vehicle or the like, and whose cross section in the direction of the rotating shaft has a rectangular inner air gap, a pair of internal external magnet support rings 8 which is disposed in the inner air-gap in the guide tube 5 and at least either of which rotates, a plurality of magnets 12 disposed circumferentially in the magnet support rings 8 at regular intervals, and a plurality of magnetic plate 6, each of which is formed out of a soft magnetic body and disposed at positions to face the magnets 12 on both sidewalls of the guide tube 5, and generates braking force on the braking disc 3 by eddy current, based on a magnetic field from the magnets 12. The magnetic plates 6 are formed on a thick-wall part facing the magnet 12 either on the inner or on the outer surfaces of both sidewalls formed out of the soft magnetic body of the guide tube 5, and a thin-wall part is formed at a part, which does not face magnets 12 either on the inner or on the outer surfaces of both side-walls.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current reduction device for assisting, for example, a friction brake of a vehicle, and more particularly to an eddy current reduction device having a magnetic plate and an integrated guide cylinder which is simple in construction and easy to manufacture. .

[0002]

2. Description of the Related Art An eddy current reduction device having a magnet support wheel having a permanent magnet (hereinafter simply referred to as a magnet) between a pair of braking disks connected to a rotating shaft as disclosed in Japanese Patent Publication No. 6-101922. Then, the ferromagnetic plate covering the magnet must be made quite thick (generally 10 to 16 mm) so that the magnetic field from the magnet does not leak out during non-braking. A ferromagnetic plate was cast or non-magnetic stainless steel was formed into a disk shape by a metal mold press, and a number of openings were provided at equal intervals in the circumferential direction. The ferromagnetic plate was fitted into the openings and then welded. . The former method requires a lot of trouble in welding, so that it is difficult to reduce the processing cost, and the latter method has a high defective casting rate to the aluminum casting.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to form a thick portion corresponding to a conventional ferromagnetic plate integrally with a guide cylinder made of a soft magnetic material or a ferromagnetic material. An object of the present invention is to provide an inexpensive eddy current reduction device which is simple to manufacture.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a construction of the present invention comprises a pair of brake discs connected to a rotating shaft, and mounted between the brake discs to a non-rotating portion such as a vehicle body. A guide cylinder made of a non-magnetic material having a hollow space having a rectangular cross section in the direction of the rotation axis, a pair of inner and outer magnet support wheels, at least one of which rotates around the hollow space of the guide tube; The magnet support wheel includes a plurality of magnets disposed at equal intervals in a circumferential direction inside the magnet support wheel, and a plurality of magnetic plates made of a soft magnetic material disposed at positions opposite to the magnets on both side walls of the guide cylinder. In an eddy current reduction device for generating a braking force by an eddy current based on a magnetic field from the magnet in the braking disk, both side walls of the guide cylinder are formed of a soft magnetic material and provided on the inner surface or the outer surface of both side walls. The magnetic plate is formed by the thick portion facing the magnet, Characterized in that the formation of the thin-walled portion of the inner or outer surface the magnet facing parts not.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, both side walls of a guide cylinder which covers the side surfaces of a magnet are made of a soft magnetic material, the thickness of a portion corresponding to a magnetic plate is increased, and the thickness of a portion not facing the magnet is reduced. make it thin. It is preferable that the thick portion is configured to protrude from the inner surface of the side wall of the guide cylinder, but it is arranged at the center of the thickness of the side wall of the guide cylinder, or is protruded from the outer surface of the side wall of the guide cylinder. It may be provided. Specifically, the side wall of the guide cylinder is forged into an annular plate made of a soft magnetic material to form a thick portion corresponding to the magnetic plate and a thin portion between the magnetic plates. Further, the thick portion and the thin portion may be formed by casting.

[0006]

1 is a front sectional view of an eddy current reduction device according to the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a developed sectional view thereof. The eddy current reduction device according to the present invention includes, for example, a braking disk 3 composed of a pair of conductors coupled to an output rotation shaft 2 of a vehicle transmission, and a soft magnetic body disposed between the braking disks 3. The guide cylinder 5 includes a pair of inner and outer magnet support wheels 8 and 10 made of a non-magnetic material and supported in the inner space of the guide cylinder 5 so as to be relatively rotatable. The braking disk 3 is fixed by spline-fitting the boss 3a to the rotating shaft 2, and has a boss 3a, a plurality of spokes 3b extending radially from the boss 3a, and a plurality of ventilation passages 3c extending radially. Are integrally formed, for example, by casting. Annular bodies or annular plates 23 and 24 made of a good conductor such as copper are joined to portions of the braking disk 3 that are not opposed to the magnetic plate (pole piece) 6 at the outer peripheral edge and the inner peripheral edge. Each of the annular plates 23 and 24 gives the eddy current flowing inside the braking disk 3 a radial expansion so as to increase the braking torque.

The guide cylinder 5 has an inner space having a rectangular cross section. Specifically, an outer cylinder 21 and an inner cylinder 22 are connected to a pair of left and right annular side wall plates. The inner cylinder 22 is formed integrally with a plurality of spokes 5 b extending in the radial direction from the boss 5 a, and the boss 5 a is supported on the rotating shaft 2 by the bearing 4. The guide tube 5 is fixed by a suitable means, for example, to a gearbox of a transmission. A large number of thick portions, that is, magnetic plates (pole pieces) 6 are formed at equal intervals in the circumferential direction on both side wall plates of the guide cylinder 5.
An inner magnet support wheel 8 that supports a number of magnets 12 is rotatably supported by a bearing 7 inside the guide cylinder 5. An outer magnet support wheel 10 that supports a large number of magnets 13 is rotatably supported by a bearing 9 on an outer peripheral wall of an inner magnet support wheel 8. A thin sliding plate 14 impregnated with lubricating oil is sandwiched between both side surfaces of the magnet support wheels 8 and 10, and slides on the inner surface of the magnetic plate 6.

As shown in FIG. 2, the inner magnet support wheel 8 is made of a non-magnetic material such as aluminum, and a large number of sector-shaped magnets 12 are opposed to the magnetic plate 6 and have a polarity with respect to the magnetic plate 6 in the circumferential direction. Are arranged so as to be alternately different. Preferably, the magnet 12 is cast into the magnet support wheel 8. Similarly, a large number of magnets 13 are arranged on the outer magnet support wheel 10 so as to face each magnetic plate 6. A pinion 15 of an electric motor 16 fixed to the guide cylinder 5 meshes with a partial gear 18 formed on the outer peripheral wall of the magnet support wheel 10, and the magnet support wheel 10 can be rotated forward and backward by an arrangement pitch p of the magnet 13. You. However, the magnet support wheel 8 may be supported so as to be able to rotate forward and backward by the arrangement pitch p of the magnets 12.

The magnetic plate 6 has a fan shape with an area covering the side surfaces of the pair of magnets 12 and 13 inside and outside. As shown in FIG.
Both side walls of the guide tube 5 are made of a soft magnetic material, and the inner surfaces of both side walls have thick portions facing the magnets 12 and 13 so that the magnetic plate 6
Are formed, and thin portions are formed in portions not facing the magnets 12 and 13.

Next, the operation of the eddy current reduction device according to the present invention will be described. While a pair of braking disks 3 are rotated together with the rotating shaft 2, as shown in FIG.
In the arrangement in which the polarities of the inner and outer magnets 12 and 13 with respect to the magnetic plate 6 are different, the short-circuit magnetic circuit z
Occurs and does not apply a magnetic field to the braking disk 3. Since the pair of magnetic plates 6 sandwich the magnets 12 and 13 from both sides, almost no magnetic flux leaks to the braking disk 3, and the braking disk 3 receives no drag torque.

When the outer magnet support wheel 10 is rotated by the electric motor 16 by the arrangement pitch p of the magnets 12 and 13 during braking, as shown in FIG. 2, the polarities of the inner and outer magnets 12 and 13 with respect to the magnetic plate 6 are the same. become. Therefore, as shown in FIG. 3, the inner and outer magnets 12 and 13 (see FIG. 2) equally apply a magnetic field to the braking disk 3 via the magnetic plate 6. When the rotating brake disc 3 crosses the magnetic field, an eddy current is generated in the brake disc 3 and the brake disc 3 receives a braking torque. At this time, the magnetic plate 6, the braking disk 3, the adjacent magnetic plate 6,
A magnetic circuit w is generated between the adjacent magnet 12, the opposite magnetic plate 6, the opposite braking disk 3, and the adjacent magnetic plate 6. Magnet 13
A similar magnetic circuit is generated between the pair of left and right braking disks 3.

As described above, the magnetic plates 6 on both side walls of the guide cylinder 5 are short-circuited on the surface including the rotating shaft 2 by the rotational differential of the magnet arrangement pitch of the inner and outer magnet support wheels 8 and 10. z
And a braking state where a magnetic circuit w for applying a magnetic field from the side wall surface of the guide cylinder 5 to the braking disk 3 is formed.

As shown in FIGS. 4 to 6, a short-circuit magnetic circuit z
If the thickness of the magnetic plate 6 at the center in the radial direction is made thicker than the inner and outer peripheral portions when forming the magnetic plate 6, the magnetic flux density at the center in the radial direction becomes denser than the others, so that more efficient short-circuiting is possible. The magnetic circuit z is formed, and the leakage magnetic flux reaching the braking disk 3 can be reduced more efficiently. In the modified embodiment shown in FIG. 4, the thickness of the magnetic plate 6 at the central portion in the radial direction is increased, and the magnets 12 and 13 are tapered so as to be thinner at the portions in contact with each other (the portions adjacent to the bearing 9). It was done.
In the modified embodiment shown in FIG. 5, the magnetic plate 6 is stepped so that the thickness of the central portion is thick and the thickness of the inner and outer peripheral edges is thin. 12,
Reference numeral 13 has a T-shaped cross section. In the modified embodiment shown in FIG. 6, the inner surface of the magnetic plate 6 is projected in an arc shape. In the modified embodiment shown in FIG. 7, the outer surface of the magnetic plate 6 protrudes in a mountain shape, and a V-shaped annular groove 19 is formed in the braking disk 3 corresponding to the outer surface of the magnetic plate 6.

As shown in FIGS. 8 to 10, the side wall plate of the guide cylinder 5 made of a soft magnetic material such as a steel material has a thick magnetic plate 6 protruding on both inner and outer surfaces, and a thin portion 6a located at an intermediate position. You may comprise. The magnetic circuit w generated between the braking magnets 12 and 13 and the pair of magnetic plates 6 is dragged in the direction of rotation of the braking disk 3 as indicated by the arrow x as the rotation speed of the braking disk 3 increases. Since the shape of the magnetic plate 6 is distorted, the shape of the plane cross section of the magnetic plate 6 is smaller than that of the rectangular shape shown in FIG.
Are preferred. In the embodiment shown in FIG.
The outer surface of the front end surface (the end surface in the rotation direction front of the braking disk 3) is cut to form the inclined surface 26a, and the outer surface of the rear end surface is similarly cut to form the inclined surface 26b.
The magnetic flux from 2 and 13 can be squeezed (to increase the magnetic flux density) and guided to the braking disk 3 to increase the braking torque. FIG.
In the embodiment shown in FIG. 0, the rear end face is further inclined in the rotation direction indicated by the arrow x of the braking disk 3 to form the inclined surface 26b, so that the magnetic flux from the magnets 12 and 13 when the braking disk 3 rotates at high speed. Can be narrowed down to the front end of the magnetic plate 6 (in the rotation direction of the braking disk 3).

In the embodiment shown in FIGS.
A large number of magnetic plates (pole pieces) 6 composed of thick portions and thin portions 6a are formed alternately in the circumferential direction and at regular intervals in the circumferential direction on both side walls made of the soft magnetic material. A pair of left and right magnet support wheels 8, which support the same number of magnets 12, 12a as the magnetic plate 6,
8a is rotatably supported in the inner space of the guide cylinder 5 by bearings 7, 7a. A thin sliding plate 14 impregnated with lubricating oil is connected to the outer surfaces of the magnet support wheels 8 and 8a, and is slidably contacted with the magnetic plate 6. The right magnet support wheel 8a is made of a non-magnetic material such as aluminum, and has the same number of fan-shaped magnets 1 as the magnetic plate 6.
2a is disposed so as to face the magnetic plate 6 and to have the polarity to the magnetic plate 6 alternately different in the circumferential direction. Preferably,
The magnet 12a is cast into the magnet support wheel 8a. Similarly, the magnet support wheel 8 on the left side has the same number of magnets 12 as the magnetic plate 6 disposed opposite the magnetic plate 6. The magnet support wheel 8a can be rotated forward and backward by the arrangement pitch of the magnets 12a by means similar to that shown in FIG. Although not shown, each magnetic plate 6 has substantially the same shape as the magnets 12 and 12a. Other configurations are the same as those of the embodiment of FIG.

At the time of non-braking, the left magnet support wheel 8 is fixed,
When the right magnet support wheel 8a is rotated by the arrangement pitch, the polarities of the opposed magnets 12, 12a become the same, and the magnetic circuit is canceled, so that no magnetic field is applied to the braking disk 3.
At the time of braking, the pair of magnet support wheels 8, 8a is held at a position where the opposite left and right magnets 12, 12a have opposite polarities.
Accordingly, the left and right magnets 12 and 12a integrally apply a magnetic field perpendicular to the braking disk 3 via the magnetic plate 6. When the rotating brake disc 3 crosses the magnetic field, an eddy current is generated in the brake disc 3 and the brake disc 3 receives a braking torque. At this time, FIG.
As shown in FIG. 2, for example, the magnetic plates 6, the braking disk 3, the adjacent magnetic plates 6, and the adjacent magnets 12a, 12a,
12, a magnetic circuit w is generated on the opposite magnetic plate 6, the opposite braking plate 3, and the adjacent magnetic plate 6.

In the above embodiment, the right magnet support wheel 8a may be fixed, and the left magnet support wheel 8 may be rotated by the motor 16 or the fluid pressure actuator by the arrangement pitch of the magnets 12.

In the embodiment shown in FIGS.
A large number of thick magnetic plates 6 and thin portions 6a are formed alternately in the circumferential direction and at equal intervals in the circumferential direction on both side walls made of the soft magnetic material. The magnet support wheel 8 is rotatably supported by the bearing 7 in the inner space of the guide cylinder 5. A large number of magnets 12 are connected to the magnet support wheel 8 at equal intervals in the circumferential direction. The magnets 12 are opposed to each magnetic plate 6 by two, and are disposed so that the polarities with respect to the magnetic plate 6 differ by two in the circumferential direction. A thin sliding plate 14 impregnated with lubricating oil is sandwiched between both side surfaces of the magnet support wheel 8, and is slid on the magnetic plate 6. 2, a pinion 15 of an electric motor fixed to the guide cylinder 5 meshes with a partial gear formed on the outer peripheral wall of the magnet support wheel 8, and
The magnet support wheel 8 can be rotated forward and backward by the arrangement pitch p of the magnets 12. Other configurations are the same as those of the embodiment of FIG.

When no braking is performed, two magnets 1 adjacent in the circumferential direction
In an arrangement in which two magnetic plates 6 have different polarities from each other, a short-circuit magnetic circuit z is generated between the pair of magnetic plates 6 and no magnetic field is applied to the braking disk 3, as shown in FIG. When the magnet support wheel 8 is rotated by the arrangement pitch p of the magnets 12 during braking, the two magnets 12 facing the common magnetic plate 6 have the same polarity. Therefore, as shown in FIG.
Two magnets 12 equally apply a magnetic field to the braking disc 3 via the magnetic plate 6. When the rotating brake disc 3 crosses the magnetic field, an eddy current is generated in the brake disc 3 and the brake disc 3 receives a braking torque. At this time, a magnetic circuit is transferred from the magnet 12 to the magnetic plate 6, the braking disk 3, the adjacent magnetic plate 6, the adjacent magnet 12, the opposite magnetic plate 6, the opposite braking disk 3, and the adjacent magnetic plate 6. w occurs.

The embodiment shown in FIG. 16 is different from the embodiment shown in FIGS. 13 to 15 in that two magnets 12 of the same polarity are arranged in the circumferential direction.
Is one. A large number of magnetic plates 6 composed of thick portions and thin portions 6 on both side walls composed of a soft magnetic material of the guide cylinder 5
a are formed alternately in the circumferential direction and at equal intervals in the circumferential direction. One magnet 12 facing each magnetic plate 6 is coupled to the magnet support wheel 8 such that the polarity with respect to the magnetic plate 6 is alternately different in the circumferential direction. By rotating the magnet support wheel 8 by the pitch of the arrangement of the magnets 12, the two magnets 12 arranged in the circumferential direction partially oppose the magnetic plate 6 of the guide tube 5, and the non-braking to form the short-circuit magnetic circuit z One magnet 12 entirely opposes the position and the magnetic plate 6 of the guide cylinder 5, and switches to a braking position where a magnetic circuit is formed on the braking disk 3.

[0021]

As described above, according to the present invention, a pair of braking disks connected to a rotating shaft and a non-rotating portion such as a vehicle body which is mounted between the braking disks and has a rectangular cross section in the direction of the rotating shaft. A guide tube made of a non-magnetic material having an inner space, a pair of inner and outer magnet support wheels, at least one of which rotates around the inner space of the guide tube, and a circumference inside the magnet support wheel; A large number of magnets arranged at equal intervals in the direction, and a magnetic plate made of a soft magnetic material arranged in a large number of positions on both side walls of the guide cylinder opposite to the magnet, and the braking disk receives the magnet from the magnet. In an eddy current reduction device that generates a braking force by an eddy current based on a magnetic field, both side walls of the guide cylinder are formed of a soft magnetic material, and a thick portion facing the magnet provided on an inner surface or an outer surface of both side walls is used. The magnetic plate is formed and paired with the magnet on the inner surface or outer surface of both side walls. Is obtained by forming a thin portion in the portion it not, is easy to manufacture the guide tube, approximately the same braking performance as the conventional structure.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an eddy current reduction device to which the present invention is applied.

FIG. 2 is a side sectional view of the same.

FIG. 3 is a planar development sectional view of the eddy current reduction device.

FIG. 4 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 5 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 6 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 7 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 8 is a plan sectional view showing a right side wall of a guide cylinder in an eddy current reduction device according to a modified embodiment of the present invention in a developed manner.

FIG. 9 is an exploded plan sectional view showing a right side wall of a guide cylinder in an eddy current reduction device according to a modified embodiment of the present invention.

FIG. 10 is a cross-sectional plan view showing the right side wall of the guide cylinder in the eddy current reduction device according to the modified embodiment of the present invention in a developed manner.

FIG. 11 is a front sectional view of another eddy current reduction device to which the present invention is applied.

FIG. 12 is a plan sectional view showing the eddy current reduction device in a developed state.

FIG. 13 is a front sectional view of another eddy current reduction device to which the present invention is applied.

FIG. 14 is an exploded plan sectional view showing the eddy current reduction device.

FIG. 15 is a sectional plan view showing the eddy current reduction device in a developed state.

FIG. 16 is an exploded plan view showing another eddy current reduction device to which the present invention is applied.

[Explanation of symbols]

2: Output rotary shaft 3: Brake disk 4: Bearing 5: Guide cylinder 6: Magnetic plate 6a: Thin portion 8: Magnet support wheel 8
a: Magnet support wheel 9: Bearing 10: Magnet support wheel 12:
Magnet 13: Magnet 14: Sliding plate 15: Pinion 1
6: Electric motor 18: Partial gear 19: Annular groove 21: Outer cylinder 22: Inner cylinder 23: Good conductor ring 24: Good conductor ring

[Procedure amendment]

[Submission date] March 5, 1999 (1999.3.5)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (2)

[Claims] 1. A non-magnetic body having a pair of braking disks coupled to a rotating shaft and an inner space between the braking disks and attached to a non-rotating portion such as a vehicle body and having a rectangular cross section in the direction of the rotating shaft. And a pair of inner and outer magnet support wheels, at least one of which rotates at least in the inner space of the guide tube, and a plurality of circumferentially equidistantly arranged inner portions of the magnet support wheels. A magnet,
A plurality of magnetic plates made of a soft magnetic material disposed at positions opposing the magnet on both side walls of the guide cylinder, and a braking force is generated in the braking disk by an eddy current based on a magnetic field from the magnet. In the eddy current reduction device, both side walls of the guide cylinder are formed of a soft magnetic material, and the magnetic plate is formed by a thick portion facing the magnet provided on the inner surface or the outer surface of the both side walls, and the inner surface of the both side walls is formed. An eddy current reduction device characterized in that a thin portion is formed on a portion of the outer surface that does not face the magnet. 2. The eddy current reduction device according to claim 1, wherein an annular body made of a good conductor such as copper is provided on at least one edge of the braking disk not facing the magnetic plate.