JP2000299974A - Eddy current reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an eddy current reduction gear, the guide pipe of which can be worked easily and is helpful for weight reduction and for cost reduction of the reduction gear. SOLUTION: An eddy current reduction gear is provided with a pair of brake discs 3 coupled with a rotating shaft 2, an immobile guide pipe 4 arranged between the discs 3 and made of a nonmagnetic material, and at least one magnet support ring 10 which is supported in the internal space section, having a rectangular cross section of the guide pipe 5 rotatable in normal and reverse states. The reduction gear is also provided with many magnets 13 coupled with the ring 10 at regular peripheral intervals and ferromagnetic plates 6, respectively coupled with the portions facing the magnets 13 of both sidewalls 6a of the guide pipe 5. Therefore, the brake discs 3 generate braking forces, when eddy currents based on the magnetic field from the magnets 13 are supplied to the discs 3. Both sidewalls 6a of the guide pipe 5 are constituted of thin ferromagnetic stainless steel sheets, and ferromagnetic plates 6 are coupled with the portions facing the magnets 13 of either the internal or external surfaces of the sidewalls 6a. In addition, the portion of the guide pipe 3, which does not come into contact with the ferromagnetic plates 6, is changed into a nonmagnetic austenitic phase by quenching the portion from a high-temperature state.

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 guide tube integrated with a ferromagnetic plate (pole piece) which is simple in construction and easy to manufacture. It relates to a reduction gear.

[0002]

2. Description of the Related Art A vortex provided with 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. In the current reduction device, the ferromagnetic plate covering the magnet has to be considerably thick (generally 10 to 16 mm) so that the magnetic field from the magnet does not leak out when the brake is not applied. A ferromagnetic plate is cast into the guide cylinder, or non-magnetic stainless steel is formed into a disk shape by a metal mold press, and a large number of openings are provided at equal intervals in the circumferential direction. Was. The former method has a high defective casting rate of the ferromagnetic plate into the aluminum casting, and the latter method requires a lot of trouble in welding the ferromagnetic plate, so that it is difficult to reduce the processing cost.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an eddy current reduction device in which the processing of a guide cylinder is easy, which is useful for reducing the weight and cost.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a pair of brake discs connected to a rotating shaft, and a non-rotating body such as a car body provided between the pair of brake discs. A guide cylinder which is attached to a portion and which is formed of a non-magnetic material and has a hollow space having a rectangular cross section in the direction of the rotation axis, and at least one magnet support wheel which is supported by the hollow space of the guide tube so as to be capable of rotating forward and reverse. And a plurality of magnets coupled to the magnet support wheel at equal intervals in the circumferential direction, and a ferromagnetic plate coupled to portions of both side walls of the guide cylinder opposed to the respective magnets. In an eddy current reduction device that generates a braking force by an eddy current based on a magnetic field from a magnet, both side walls of the guide tube are formed of a ferromagnetic stainless steel thin plate, and one of the magnets on one of inner and outer surfaces of the both side walls is provided. The ferromagnetic plate is coupled to a portion facing and
A portion of the guide cylinder not in contact with the ferromagnetic plate is rapidly cooled from a high temperature state to a nonmagnetic austenitic phase.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a magnet support wheel is supported in a rectangular hollow inner space of a guide tube made of a non-magnetic material so as to be able to rotate forward and backward, and both side walls of the guide tube covering the outer surface of the magnet are provided. It is made of a ferromagnetic stainless steel thin plate, and a ferromagnetic plate (pole piece) is connected to the inner or outer surface of each side wall facing the magnet by welding or the like. A portion of the side wall of the guide cylinder that is not in contact with the ferromagnetic plate is locally heated by a method such as high-frequency heating and rapidly cooled from a high temperature state of 800 ° C. or higher to form a nonmagnetic austenite phase. As a result, the same function as that of the conventional guide cylinder can be obtained. The ferromagnetic stainless steel is, for example, 13 chromium (Cr) stainless steel.

A good conductor such as copper may be attached to a portion of the braking drum that does not face the ferromagnetic plate so that an eddy current can easily flow.

[0007]

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 is, 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 non-magnetic disposed between the pair of braking disks 3. And a pair of inner and outer magnet support wheels 8 and 1 made of a non-magnetic material rotatably supported in the inner space of the guide cylinder 5.
0. 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. An annular body or an annular plate 2 made of a good conductor such as copper is provided on the outer peripheral edge and the inner peripheral edge of the braking disk 3 at a portion not facing the ferromagnetic plate (pole piece) 6.
3, 24 are combined. 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 tube 5 has an annular inner space having a rectangular cross section. Specifically, the outer cylinder 21 made of a non-magnetic material
And an end portion of the inner cylinder 22 and a side wall 6a formed of an annular plate. The side wall 6a is made of a ferromagnetic stainless steel thin plate such as 13 chromium (Cr) stainless steel or the like, and the ferromagnetic plate (pole) is welded to a portion of the inner surface of both side walls 6a facing the magnets 12 and 13. Pieces) 6 are joined. A portion 6b of the side wall 6a of the guide cylinder 5 which is not in contact with the ferromagnetic plate 6 is locally heated by a method such as high-frequency heating and rapidly cooled from a high temperature state of 800 ° C. or higher to form a nonmagnetic austenite phase. 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 to, for example, a gearbox of a vehicle transmission. An inner magnet support wheel 8 supporting a large number of magnets 12 is fixed inside the guide cylinder 5 or a bearing 7.
To be rotatably supported. 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. Thin sliding plate 14 impregnated with lubricating oil on both sides of magnet support wheels 8 and 10
Are coupled to each other so that the inner surface of the ferromagnetic plate 6 can slide.

As shown in FIG. 2, the inner magnet support wheel 8 is made of a non-magnetic material such as aluminum, and a fan-shaped magnet 12 is opposed to each ferromagnetic plate 6 and has a polarity around the ferromagnetic plate 6. They are arranged so as to be alternately different in the direction. Preferably, the magnet 12 is cast into the magnet support wheel 8. Similarly, the outer magnet support wheel 10 is also provided such that a large number of magnets 13 face each ferromagnetic plate 6 and that the polarities with respect to the ferromagnetic plate 6 are alternately different in the circumferential direction. A pinion 15 of an electric motor 16 fixed to the guide tube 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 the arrangement pitch p. However, instead of the magnet support wheel 10, the magnet support wheel 8 may be supported by the arrangement pitch p of the magnets 12 so as to be able to rotate forward and backward. Each ferromagnetic plate 6 has a fan shape with an area covering the side surfaces of the pair of magnets 12 and 13 inside and outside.

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 an arrangement in which the inner and outer magnets 12 and 13 have different polarities with respect to the ferromagnetic plate 6, a short-circuit magnetic circuit z is generated between the pair of left and right ferromagnetic plates 6, and no magnetic field is applied to the braking disk 3. Since the pair of ferromagnetic 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 13 during braking, FIG.
As shown in FIG. 7, the polarities of the inner and outer magnets 12 and 13 with respect to the ferromagnetic plate 6 become the same. Therefore, as shown in FIG. 3, the inner magnet 12 and the outer magnet 13 (the magnet 12 is
) Equally apply a magnetic field to the braking disk 3 via the ferromagnetic 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, from each magnet 13, the ferromagnetic plate 6, the braking disk 3, the adjacent ferromagnetic plate 6, the adjacent magnet 13, the opposite ferromagnetic plate 6, the opposite braking disk 3, and the adjacent ferromagnetic plate 6, a magnetic circuit w is generated. The magnet 12 also generates a similar magnetic circuit between the pair of left and right braking disks 3.

As described above, the ferromagnetic plates 6 on both side walls 6a of the guide cylinder 5 are short-circuited on the surface including the rotating shaft 2 due to the rotational differential of the magnet arrangement pitch of the inner and outer magnet support wheels 8, 10. Switching is made between a non-braking state in which the magnetic circuit z is formed and a braking state in which a magnetic circuit w for applying a magnetic field to the braking disk 3 via the side wall 6a of the guide cylinder 5 on the circumferential surface is formed.

As shown in FIGS. 4 to 6, a short-circuit magnetic circuit z
Is formed, the thickness of the radially central portion of the ferromagnetic plate 6 is
If it is thicker than the inner and outer peripheral edges, the magnetic flux density in the radial center becomes denser than the others, so that a more efficient short-circuit magnetic circuit z is formed, and the leakage magnetic flux reaching the brake disk 3 is further reduced. Can be reduced. In the modified embodiment shown in FIG. 4, the thickness of the radially central portion of the ferromagnetic plate 6 is increased, and the magnets 12 and 13 are tapered so as to be thinner by the corresponding portion (the portion adjacent to the bearing 9). It was made. In the modified embodiment shown in FIG. 5, the ferromagnetic 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, and corresponds to the inner surface of the ferromagnetic plate 6. The magnets 12 and 13 have a T-shaped cross section. 6, the inner surface of the ferromagnetic plate 6 is projected in an arc shape. FIG.
In the modified embodiment shown in FIG. 5, the ferromagnetic plate 6 is coupled to the outer surface of the side wall 6a, and the outer surface of the ferromagnetic plate 6 is projected in a mountain shape. Is formed with a V-shaped annular groove 19.

As shown in FIG. 8, the thick ferromagnetic plate 6 coupled to the side wall 6a of the guide cylinder 5 made of a thin plate such as 13 chromium (Cr) stainless steel may have a rectangular cross section in plan view. Is a pair of ferromagnetic plates 6 with the magnets 12 and 13 during braking.
The magnetic circuit w generated between the two becomes distorted in the rotational direction of the braking disk 3 as indicated by an arrow x as the rotation speed of the braking disk 3 increases, so that the shape shown in FIGS. Is preferred. In the embodiment shown in FIG. 9, the outer surface side of the front end surface (the end surface in the rotation direction front of the braking disk 3) is cut off to form the inclined surface 2.
6a, and similarly, by cutting off the outer surface side of the rear end surface to form the inclined surface 26b, the magnetic flux from the magnets 12 and 13 is narrowed (to increase the magnetic flux density) and guided to the braking disk 3, and the braking is performed. The torque can be increased. In the embodiment shown in FIG. 10, the rear end surface of the ferromagnetic plate 6 is formed with an inclined surface 26 b that is further inclined in the rotation direction of the braking disk 3 indicated by the arrow x, so that the magnet at the high speed rotation of the braking disk 3 is formed. The magnetic flux from 12 and 13 can be narrowed down to the front end of the ferromagnetic plate 6 (the rotation direction of the braking disk 3). 8 to 10, the portion 6b of the side wall 6a of the guide cylinder 5 which is not in contact with the ferromagnetic plate 6 is formed into a non-magnetic austenite phase by rapidly cooling from a high temperature state of 800 ° C. or higher.

In the embodiment shown in FIGS.
The thick ferromagnetic plate 6 is joined to the inner surfaces of both side walls 6a made of a thin plate of 13 chromium (Cr) stainless steel or the like.
The portions 6b of the side walls 6a which are not in contact with the ferromagnetic plate 6 have a temperature of 8
A non-magnetic austenitic phase is formed by rapid cooling from a high temperature state of 00 ° C. or higher. A pair of left and right magnet support wheels 8, 8a supporting the same number of magnets 12, 12a as the ferromagnetic plate 6
Are supported by bearings 7 and 7a in the inner space of the guide cylinder 5 so as to be able to rotate forward and backward. A thin sliding plate 14 impregnated with lubricating oil is connected to the outer surfaces of the magnet support wheels 8 and 8a, and can slide on the ferromagnetic plate 6. The right magnet support wheel 8a is made of a non-magnetic material such as aluminum, and the same number of fan-shaped magnets 12a as the ferromagnetic plate 6 are opposed to the ferromagnetic plate 6 and the polarity with respect to the ferromagnetic plate 6 alternates in the circumferential direction. Arranged differently.
Preferably, the magnet 12a is cast into the magnet support wheel 8a. Similarly, the magnet support wheel 8 on the left side is provided such that the same number of magnets 12 as the ferromagnetic plate 6 face the ferromagnetic plate 6 and the polarity with respect to the ferromagnetic plate 6 is alternately different in the circumferential direction. 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 ferromagnetic 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 pitch of the arrangement of the magnets 12a, the opposite magnets 12 and 12a have the same polarity, and the magnetic circuit is cancelled, 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 right and left magnets 12 and 12a integrally apply a magnetic field perpendicular to the braking disk 3 via the ferromagnetic plate 6. When the rotating brake disk 3 crosses the magnetic field, the brake disk 3
Generates an eddy current, and the braking disk 3 receives a braking torque.
At this time, for example, as shown in FIG.
a to the ferromagnetic plate 6, the braking disk 3, the adjacent ferromagnetic plate 6, the adjacent magnets 12a and 12, the opposite ferromagnetic plate 6, the opposite braking disk 3, and the adjacent ferromagnetic plate 6. A magnetic circuit w results.

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 ferromagnetic plates 6 are joined at equal intervals in the circumferential direction to the inner surfaces of both side walls 6a made of a thin plate made of 13 chrome (Cr) stainless steel or the like. Portion 6 of sidewall 6a not in contact with ferromagnetic plate 6
b is formed into a nonmagnetic austenite phase by rapidly cooling from a high temperature state of 800 ° C. or higher. The magnet support wheel 8 is supported by a bearing 7 in the inner space of the guide cylinder 5 so as to be capable of rotating forward and backward. The magnets 12 are coupled to the magnet support wheel 8 at equal intervals in the circumferential direction. The magnets 12 are arranged two by two with respect to each ferromagnetic plate 6, and are arranged such that the polarities with respect to the ferromagnetic plate 6 differ by two in the circumferential direction. A thin sliding plate 14 impregnated with lubricating oil is supported on both side surfaces of the magnet support wheel 8, and is brought into sliding contact with the ferromagnetic 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 Only forward and reverse rotation is possible. Other configurations are the same as those of the embodiment of FIG.

When the brake is not applied, the polarities of the two magnets 12 adjacent to each other in the circumferential direction with respect to the common ferromagnetic plate 6 are different from each other, and as shown in FIG.
A short-circuited magnetic circuit z occurs between them and does not exert a magnetic field on the braking disc 3. 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 ferromagnetic plate 6 have the same polarity. Accordingly, as shown in FIG. 15, the two magnets 12 equally apply a magnetic field to the pair of braking disks 3 via the ferromagnetic plate 6. When a pair of rotating brake disks 3 cross the magnetic field, an eddy current is generated in the brake disks 3 and the brake disks 3 receive a braking torque. At this time, magnet 1
From 2 to a ferromagnetic plate 6, a braking disk 3, an adjacent ferromagnetic plate 6, an adjacent magnet 12, an opposite ferromagnetic plate 6, an opposite braking disk 3, and an adjacent ferromagnetic 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. 13 chrome (Cr) of guide tube 5
Thick ferromagnetic plates 6 are joined to both side walls 6a made of a thin plate of stainless steel or the like at equal intervals in the circumferential direction. One magnet 12 facing each ferromagnetic plate 6 is coupled to the magnet support wheel 8 such that the polarity with respect to the ferromagnetic plate 6 is alternately different in the circumferential direction. By rotating the magnet support wheel 8 by a half pitch of the magnets 12, the two magnets 12 arranged in the circumferential direction partially face the ferromagnetic plates 6 on both side walls 6a of the guide cylinder 5, and a short-circuit magnetic circuit is formed. When one magnet 12 entirely opposes the non-braking position (FIG. 16) forming z and the ferromagnetic plate 6 of the guide cylinder 5,
It switches to a braking position where a magnetic circuit is formed between the pair of braking disks 3.

[0021]

As described above, the present invention relates to a pair of brake discs connected to a rotating shaft and a pair of brake discs, which are mounted on a non-rotating part such as a vehicle body and are disposed between the pair of brake discs in the direction of the rotary shaft. A guide tube made of a non-magnetic material having an inner space portion having a rectangular cross section, at least one magnet support wheel supported in the inner space portion of the guide tube so as to be able to rotate forward and reverse, and a circumferential direction provided on the magnet support wheel; It has a large number of magnets coupled at equal intervals, and a ferromagnetic plate coupled to a portion of each side wall of the guide cylinder opposite to each magnet, and the braking disk has an eddy current based on a magnetic field from the magnet. In the eddy current reduction device for generating a braking force, both side walls of the guide cylinder are formed of a ferromagnetic stainless steel thin plate, and the ferromagnetic plates are provided at portions of the inner and outer surfaces of the both side walls facing one of the magnets. And the part of the guide cylinder that is not in contact with the ferromagnetic plate is Since the non-magnetic austenite phase is obtained by quenching, the processing of the guide tube is simplified, and the yield is better and the processing cost is higher than that of the conventional case where the ferromagnetic plate is cast into an outer guide tube made of aluminum or the like. And saves weight.

[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 cross-sectional plan view showing the left side wall of the guide cylinder in the eddy current reduction device according to the modified example of the present invention in a developed manner.

FIG. 9 is a cross-sectional plan view showing the left side wall of the guide cylinder in the eddy current reduction device according to the modified example of the present invention in a developed manner.

FIG. 10 is a plan sectional view showing the left side wall of the guide cylinder in the eddy current reduction device according to the modified example 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 rotating shaft 3: Brake disk 4: Bearing 5: Guide cylinder 6: Ferromagnetic plate 6a: Side wall 6b: Portion not in contact with ferromagnetic plate 8: Magnet support wheel 8a: Magnet support wheel 9: Bearing 10: Magnet Support wheel 12: Magnet 13: Magnet 14:
Sliding plate 15: Pinion 16: Electric motor 18: Partial gear 19: Annular groove 21: Outer cylinder 22: Inner cylinder 23: Good conductor ring 24: Good conductor ring

Claims (2)

[Claims] A pair of braking disks coupled to a rotating shaft;
A guide cylinder made of a non-magnetic body having a rectangular hollow section with a rectangular cross section in the direction of the rotation axis, which is mounted between a pair of braking disks and attached to a non-rotating portion such as a vehicle body; At least one rotatably supported magnet support wheel, a large number of magnets connected to the magnet support wheel at equal intervals in the circumferential direction, and a strong connection connected to portions of both side walls of the guide cylinder facing the respective magnets. An eddy current reduction device having a magnetic plate and generating a braking force by an eddy current based on a magnetic field from the magnet in the braking disk, wherein both side walls of the guide cylinder are formed of ferromagnetic stainless steel thin plates. The ferromagnetic plate is coupled to one of the inner and outer surfaces of the side walls facing the magnet, and the portion of the guide cylinder not in contact with the ferromagnetic plate is rapidly cooled from a high temperature state to thereby provide a non-magnetic austenitic phase. Eddy current deceleration characterized by Location. 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 of the inner and outer peripheral edges of the braking disk not facing the ferromagnetic plate. .