JP2001186746A - Eddy current reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a ferromagnetic part and a nonmagnetic part (or weak magnetic part) on the opposite sidewalls of a guide tube made of a thick ferromagnetic stainless steel plate by grooving and heat treatment. SOLUTION: The eddy current reduction gear comprises a pair of left and right brake discs 3 coupled with a rotary shaft 2, a guide tube 5 disposed between the pair of brake discs 3, at least one magnet supporting ring 8 supported rotatably in the cavity of the guide tube 5 having rectangular cross-section, a large number of magnets 12 carried on the magnet supporting ring 8 at a constant interval in the circumferential direction, and ferromagnetic parts 6 provided on the opposite sidewalls 16 of the guide tube 5 while facing each magnet 12 wherein a brake force is induced in the brake discs 3 with eddy currents based on the field of the magnets 12. The opposite sidewalls 16 of the guide tube 5 made of a thick ferromagnetic stainless steel plate is sectioned by a narrow radial groove 30 into a ferromagnetic part 6 facing the magnet 12 and a nonmagnetic part 6a not facing the magnet 12. The nonmagnetic part 6a is formed through quenching from high temperature molten 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 which is simple in construction and easy to manufacture. It is.

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Publication No. 6-101922, a magnet support wheel having a permanent magnet (hereinafter simply referred to as a magnet) is provided between a pair of left and right braking disks connected to a rotating shaft. In the eddy current reduction device, the ferromagnetic plate (pole piece) covering the magnet is made quite thick (generally 10 to 16) so that the magnetic field from the magnet does not leak outside during non-braking.
mm). For this reason, a ferromagnetic plate is cast into a guide cylinder made of an aluminum casting, or a non-magnetic stainless steel plate is formed into a disk shape by a die press, and a large number of openings are provided at equal intervals in the circumferential direction. The magnetic plate was fitted and welded. The former method has a high defective casting rate of the ferromagnetic plate with respect to 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, it is an object of the present invention to form both side walls of a guide cylinder from a thick stainless steel plate, which is a ferromagnetic material, and leave a ferromagnetic portion facing a magnet, An object of the present invention is to provide an inexpensive eddy current reduction device in which a nonmagnetic or weak magnetic portion which does not face a magnet is formed by heat treatment and characteristics between the two are clarified, and which is easy to manufacture and inexpensive.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a configuration of the present invention is provided on a pair of left and right braking disks coupled to a rotating shaft and on a non-rotating portion between the pair of left and right braking disks. A guide cylinder having an inner space portion having a rectangular cross section, and at least one magnet support wheel rotatably supported by the inner space portion of the guide tube;
A large number of magnets supported at equal circumferential intervals on the magnet support wheel,
An eddy current reduction device having a ferromagnetic portion facing each of the magnets provided on both side walls of the guide cylinder and generating a braking force on the braking disk by eddy current based on a magnetic field from the magnet; By forming both side walls of the guide cylinder from a thick stainless steel plate which is a ferromagnetic material, a part of the both side walls which does not oppose the ferromagnetic part opposing the magnet is solutionized and rapidly cooled from a high temperature state. It is non-magnetic or weakly magnetic, and a narrow radial groove is provided at the boundary between the non-magnetic or weakly magnetic portion and the ferromagnetic portion of the both side walls facing the magnet.

[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 support wheel are made of a thick stainless steel plate which is a ferromagnetic material. The non-facing portion is heated to a temperature of 800 to 1350 ° C. to form a solution, then rapidly cooled to non-magnetic or weak magnetic, and a small amount is formed at the boundary between the ferromagnetic portion facing the magnet and the non-magnetic or weak magnetic portion not facing the magnet. Both process radial grooves. In other words, portions of the guide cylinder that are not opposed to the magnets on both sides are heated to a temperature of 800 to 1350 ° C., turned into a solution, and rapidly cooled, and then transformed into a nonmagnetic or weakly magnetic austenitic phase. Since both side walls of the guide tube are made of thick stainless steel plate and only groove processing and heat treatment are performed on both side walls, the production is simple, which helps to reduce the production cost.

Further, the characteristics of the ferromagnetic portion and the non-magnetic or weak magnetic portion are clearly separated by the boundary grooves, so that the short-circuit magnetic circuit during non-braking and the magnetic circuit during braking are efficiently formed. , Leakage flux is reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an 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 rotating shaft 2 of a vehicle transmission, and a pair of braking circles. A stationary guide cylinder 5 disposed between the plates 3 and a pair of inner and outer magnet support wheels 8 and 10 made of a nonmagnetic material rotatably supported in an inner space of the guide cylinder 5 having a rectangular cross section; It has. The braking disk 3 is fixed by spline-fitting the boss 3a to the rotating shaft 2, and includes, for example, the boss 3a, a plurality of spokes 3b extending radially from the boss 3a, and a disk portion having a plurality of ventilation passages 3c extending radially. It is formed integrally by casting.

The guide cylinder 5 may be formed by connecting the outer cylinder 21 and the inner cylinder 22 between a pair of left and right annular side walls 16 to form an inner space having a rectangular cross section. An annular plate is connected to a cylindrical body having a groove-shaped cross section. Inner cylinder 22 is boss 5a
The boss 5 a is formed integrally with a plurality of spokes 5 b extending radially from the shaft 5, 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 transmission. An inner magnet support wheel 8 that supports a large number of magnets 12 at equal intervals in the circumferential direction is rotatably supported by a bearing 7 inside the guide cylinder 5. The outer magnet support wheel 10 that supports the same number of magnets 13 as the magnets 12 at equal intervals in the circumferential direction is rotatably supported by the bearing 9 on the outer peripheral wall of the inner magnet support wheel 8. Since the bearings 7, 9 are for obtaining relative rotation of the magnet support wheels 8, 10, only one of them may be used. Thin sliding plate 14 impregnated with lubricating oil on both sides of magnet support wheels 8 and 10
Are superimposed on each other, and can slide on the inner surfaces of both side walls 16.

As shown in FIGS. 1 to 3, 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 side wall 16 and have a polarity with respect to the side wall 16 in the circumferential direction. Are arranged so as to be alternately different. Preferably, the magnet 12 is cast into the magnet support wheel 8. The outer magnet support wheel 10 also has a large number of sector-shaped magnets 13.
However, they are arranged so as to face the side walls 16 and have polarities alternately different from each other in the circumferential direction. Although not shown,
A pinion shaft of an electric motor fixed to the outer cylinder 21 of the guide cylinder 5 meshes with a partial gear formed on the outer peripheral wall of the magnet support wheel 10, and the magnet support wheel 10 can rotate forward and backward by the arrangement pitch p of the magnet 13. It is said. However, instead of the magnet support wheel 10,
The magnet support wheel 8 may be supported by the arrangement pitch p of the magnet 12 so as to be able to rotate forward and backward. The ferromagnetic part 6 is a pair of magnets 1 inside and outside.
It is a fan-shaped one having an area covering the side surfaces 2 and 13.

As shown in FIGS. 2 and 3, in the present invention, both side walls 16 of the guide tube 5 are formed of a thick stainless steel plate which is a ferromagnetic material such as 13 chrome (Cr) stainless steel.
Ferromagnetic portions 6 facing magnets 12 and 13 on both side walls 16
At the boundary between the magnet 6 and the portion 6a that does not face the magnets 12 and 13,
A narrow radial groove 30 is provided. A portion 6a of the inner surfaces of the side walls 16 which does not face the magnets 12 and 13 has a temperature of 800 ° C.
By heating as described above to form a solution and rapidly cooling from a high temperature state, it is formed to be non-magnetic or weakly magnetic. That is, portions 6a of the side walls 16 of the guide cylinder 5 that do not face the magnets 12, 13
Is a thick stainless steel plate which is a ferromagnetic material such as 13 chromium (Cr) stainless steel.
By quenching after heating to 50 ° C to form a solution,
It is transformed into a non-magnetic or weakly magnetic austenitic phase. Preferably, grooves 30 are also provided on the outer surfaces of both side walls 16.
The grooves 30a are also provided on the outer peripheral surface and the inner peripheral surface, respectively, so that the pair of grooves 30 and the pair of grooves 30a surround the boundary between the ferromagnetic portion 6 and the nonmagnetic or weak magnetic portion 6a. Side wall 1
The grooves 30 and 30a of No. 6 may be processed after the heat treatment. However, the grooves 30 and 30a are processed before the heat treatment, and a coolant is charged into the grooves 30 and 30a, so that the grooves 30 and 30a do not face the magnets 12 and 13. It is preferable to heat-treat only the portion 6a.

As shown in FIG. 1, at least one of the inner and outer peripheral edges of the braking disk 3 which does not face the ferromagnetic portion 6 is connected with annular members 23 and 24 made of a good conductor such as copper. The eddy currents flowing inside the braking disk 3 are spread in the radial direction by the annular bodies 23 and 24, and the braking torque is increased.

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 portion 6, a short-circuit magnetic circuit z is generated between the two pairs of right and left ferromagnetic portions 6, and no magnetic field is applied to the braking disk 3. Since the pair of left and right ferromagnetic portions 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 does not receive drag torque.

During braking, the electric motor drives the outer magnet support wheel 1
When 0 is rotated by the arrangement pitch p of the magnet 13, as shown in FIG. 2, the polarities of the inner and outer magnets 12, 13 with respect to the ferromagnetic portion 6 become the same. Accordingly, the inner and outer magnets 12 and the magnets 13 (see FIG.
, A magnetic field is applied to the braking disk 3. Rotating brake disk 3
When the traverses the magnetic field, an eddy current is generated in the braking disk 3, and the braking disk 3 receives a braking torque. At this time, from each magnet 12, the ferromagnetic portion 6, the braking disk 3, the adjacent ferromagnetic portion 6, the adjacent magnet 12, the opposite ferromagnetic portion 6, the opposite braking disk 3, the adjacent ferromagnetic portion 6, a magnetic circuit w is generated. The magnet 13 also generates a similar magnetic circuit w between the pair of left and right braking disks 3.

As described above, the inner and outer magnet support wheels 8, 10
The rotational differential of the arrangement pitch p of the magnets 12 and 13 is such that the ferromagnetic portions 6 of the side walls 16 of the guide cylinder 5 form a short-circuited magnetic circuit z on the plane including the rotating shaft 2 and the non-braking state. A magnetic field is applied to the braking disk 3 from the side wall 16 of the cylinder 5 to switch to a braking state in which a magnetic circuit w is formed.

Ferromagnetic part 6 and non-magnetic or weak magnetic part 6
By providing the groove 30 at the boundary with
The magnetic characteristics of “a” are clearly defined, the short-circuit magnetic circuit during braking and the magnetic circuit during braking are efficiently formed, the leakage magnetic flux is reduced, and the drag torque during non-braking is suppressed.

In the embodiment shown in FIGS. 4 and 5, both side walls 16 made of a thick stainless steel plate which is a ferromagnetic material of the guide cylinder 5 are used.
A large number of ferromagnetic portions 6 and non-magnetic or weak magnetic portions 6a
Are alternately formed in the circumferential direction. A pair of left and right magnet support wheels 8, which support the same number of magnets 12, 12a as the ferromagnetic portion 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 can slide on the inner surface of the side wall 16. 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 portion 6 face the ferromagnetic portion 6 of the right side wall 16 and have a polarity relative to the ferromagnetic portion 6. They are arranged so as to be alternately different in the direction. Preferably, the magnet 12a is cast into the magnet support wheel 8a. Similarly, the left magnet support wheel 8
Is also made of a non-magnetic material such as aluminum and has a ferromagnetic portion 6
Are arranged in such a manner as to face the ferromagnetic portion 6 of the left side wall 16 and to have the polarity to the ferromagnetic portion 6 alternately different in the circumferential direction. The magnet support wheel 8a is shown in FIG.
By means similar to those shown in (1), the magnet 12a can be rotated forward and backward by the arrangement pitch of the magnet 12a. Although not shown, each ferromagnetic portion 6 has substantially the same shape as the magnets 12 and 12a.

The both side walls 16 of the guide tube 5 are made of 13 chrome (C
r) A ferromagnetic thick steel plate such as a series stainless steel or the like, which is made of a thick stainless steel plate.
A non-magnetic or weak magnetic material is provided by providing a narrow radial groove 30 and heating a portion 6a of the inner surface of both side walls 16 which is not opposed to the magnets 12 and 12a to a temperature of 800 ° C. or more to a solution and rapidly cooling from a high temperature state. To form Preferably, grooves 30 are formed on the outer surfaces of both side walls 16 and grooves 30a are formed on the outer and inner circumferential surfaces.
Are provided so that the pair of grooves 30 and the pair of grooves 30a surround the boundary between the ferromagnetic portion 6 and the nonmagnetic or weak magnetic portion 6a. 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 12, the opposite magnets 12 and 12a have the same polarity, 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 right and left magnets 12 and 12a integrally apply a perpendicular magnetic field to the pair of left and right braking disks 3 via the pair of right and left ferromagnetic portions 6. When the rotating pair of left and right braking disks 3 crosses the magnetic field, an eddy current is generated in the pair of left and right braking disks 3, and the pair of left and right braking disks 3 receives braking torque.
At this time, as shown in FIG. 5, from the magnets 12 and 12a, the ferromagnetic portion 6, the braking disk 3, the adjacent ferromagnetic portion 6, the adjacent magnets 12a and 12, the opposite ferromagnetic portion 6, and the opposite ferromagnetic portion 6. A magnetic circuit w is generated in the braking disk 3 and the adjacent ferromagnetic portion 6.

In the above-described embodiment, the right magnet support wheel 8a may be fixed, and the left magnet support wheel 8 may be rotated forward and backward by an electric motor or an actuator by an arrangement pitch of the magnets 12.

In the embodiment shown in FIGS. 6 to 8, both side walls 16 made of a thick stainless steel plate which is a ferromagnetic material of the guide cylinder 5 are used.
A large number of ferromagnetic portions 6 and non-magnetic or weak magnetic portions 6a
Are alternately formed in the circumferential direction. A single magnet support wheel 8 is supported in the inner space of the guide cylinder 5 by a bearing 7 so as to be able to rotate forward and backward. 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 the ferromagnetic portions 6 of the left and right side walls 16 by two, and are disposed so that the polarities of the magnets 6 are different from each other by two in the circumferential direction. A thin sliding plate 14 impregnated with lubricating oil is connected to both side surfaces of the magnet support wheel 8, and can slide on the inner surface of the side wall 16. Although not shown, partial gears formed on the outer peripheral wall of the magnet support wheel 8 include:
The pinion of the electric motor fixed to the guide tube 5 is engaged with the motor, and the magnet support wheel 8 can be rotated forward and backward by the arrangement pitch p of the magnet 12.

The both side walls 16 of the guide tube 5 are made of 13 chrome (C
r) The boundary between the ferromagnetic portion 6 facing the magnet 12 and the nonmagnetic or weak magnetic portion 6a not facing the magnet 12 on both side walls 16 which is made of a thick stainless steel plate which is a ferromagnetic material such as a series stainless steel. A narrow radial groove 30 is provided, and the portions 6a of both side walls 16 are heated to a temperature of 800 ° C. or more to form a solution, and rapidly cooled from a high temperature state to a nonmagnetic or weak magnetic austenitic phase. Preferably,
Grooves 30 are also provided on the outer surface of both side walls 16, and grooves 30a are also provided on the outer peripheral surface and the inner peripheral surface, respectively. One pair of grooves 30 and one pair of grooves 30a
Surrounds the boundary between the ferromagnetic portion 6 and the nonmagnetic or weak magnetic portion 6a. Other configurations are the same as those of the embodiment of FIG.

When no braking is applied, two magnets 1 adjacent in the circumferential direction
In the arrangement in which the polarities of the two common ferromagnetic portions 6 are different from each other, a short-circuit magnetic circuit z is generated between the pair of right and left ferromagnetic portions 6 as shown in FIG. Absent. 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 portion 6 have the same polarity. Accordingly, as shown in FIG. 7, the two magnets 12 equally apply a magnetic field to the pair of left and right braking disks 3 via the ferromagnetic portion 6. Rotating left and right 1
When the pair of braking disks 3 cross the magnetic field, an eddy current is generated in the pair of left and right braking disks 3, and the pair of left and right braking disks 3 receives a braking torque. At this time, from the magnet 12, the ferromagnetic portion 6, the braking disk 3, the adjacent ferromagnetic portion 6, the adjacent magnet 12, the opposite ferromagnetic portion 6, the opposite braking disk 3, the adjacent ferromagnetic portion 6 A magnetic circuit w is generated.

The embodiment shown in FIG. 9 differs from the embodiment shown in FIGS. 6 to 8 in that two magnets 12 of the same polarity arranged in the circumferential direction are integrated into one. The two side walls 16 of the guide cylinder 5 are made of a thick stainless steel plate which is a ferromagnetic material such as 13 chrome (Cr) stainless steel. A radial groove 30 having a small width is provided at the boundary with the portion 6a which does not face
Is heated to a temperature of 800 ° C. or higher to form a solution, and rapidly cooled from a high temperature state to form a nonmagnetic or weak magnetic austenitic phase. Preferably, grooves 30 are also provided on the outer surface of both side walls 16 and grooves 30a are also provided on the outer peripheral surface and the inner peripheral surface, respectively, so that a pair of grooves 30 and a pair of grooves 30 It surrounds the boundary with the part 6a. Other configurations are the same as those of the embodiment of FIG.

Opposing each ferromagnetic portion 6 of the side wall 16 of the guide tube 5, one magnet 12 is coupled to the magnet support wheel 8 such that the polarity of the ferromagnetic portion 6 is alternately different in the circumferential direction. By rotating the magnet support wheel 8 by a half pitch of the magnets 12, two magnets 12 arranged in the circumferential direction are partially opposed to the ferromagnetic portion 6 of the side wall 16 of the guide cylinder 5 so that the short-circuit magnetic circuit z And the side wall 16 of the guide tube 5
One magnet 12 entirely opposes the ferromagnetic portion 6 and switches to a braking position in which a magnetic circuit is formed between the ferromagnetic portion 6 and the braking disk 3.

[0025]

As described above, the present invention has a pair of left and right brake discs connected to a rotating shaft, and a hollow space having a rectangular cross section disposed at a non-rotating portion between the pair of left and right brake discs. A guide cylinder and at least one rotatably supported inner space of the guide cylinder;
One magnet support wheel, a large number of magnets supported at equal intervals in the circumferential direction on the magnet support wheel, and a ferromagnetic portion facing each of the magnets provided on both side walls of the guide cylinder; In an eddy current reduction device that generates a braking force on the braking disk by eddy current based on a magnetic field, both side walls of the guide cylinder are formed of a thick stainless steel plate that is a ferromagnetic material, and the magnets on the both side walls are The non-magnetic or weak magnetic portion is formed by partially quenching from a high temperature state by partially solutionizing the non-facing ferromagnetic portion and the non-facing portion, and the non-magnetic or weak magnetic portion and the ferromagnetic portions facing the magnets on both side walls. A narrow radial groove is provided at the boundary of, the structure is simple, the manufacture of the guide tube is easy, and the same braking performance as that of the conventional structure can be obtained, and the manufacturing cost can be reduced. .

The groove at the boundary between the ferromagnetic portion and the non-magnetic or weak magnetic portion clearly distinguishes the respective magnetic characteristics of the two, so that the short-circuit magnetic circuit during non-braking and the magnetic circuit during braking are more efficient. And the leakage magnetic flux is reduced.

An annular body made of a good conductor such as copper is connected to at least one of the inner and outer peripheral edges not facing the ferromagnetic portion of the braking disk. The eddy current flowing inside the braking disk is radially spread by the annular body, and the braking torque is increased.

[Brief description of the drawings]

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

FIG. 2 is a plan sectional view showing the eddy current reduction device in a developed state.

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

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

FIG. 5 is a cross-sectional plan view showing the eddy current reduction device in a developed state.

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

FIG. 7 is a cross-sectional plan view showing the non-braking state of the eddy current reduction device in an unfolded state.

FIG. 8 is a cross-sectional plan view showing the braking state of the eddy current reduction device in a developed state.

FIG. 9 is an exploded plan sectional view showing a non-braking state of the eddy current reduction device according to the fourth embodiment of the present invention.

[Explanation of symbols]

2: Rotary shaft 3: Brake disk 4: Bearing 5: Guide cylinder
6: Ferromagnetic part 6a: Non-magnetic or weak magnetic part
8a: Magnet support wheel 9: Bearing 10, 10a: Magnet support wheel 12, 12a: Magnet 13: Magnet 14: Sliding plate
16: Side wall 21: Outer cylinder 22: Inner cylinder 23: Good conductor ring 24: Good conductor ring 30, 30a: Groove

Claims (2)

[Claims] A pair of left and right braking disks coupled to a rotating shaft;
A guide cylinder having an inner space with a rectangular cross section disposed in a non-rotating portion between a pair of left and right braking disks, and at least one magnet support wheel rotatably supported in the inner space of the guide cylinder; It has a number of magnets supported at equal intervals in the circumferential direction on the magnet support wheel, and a ferromagnetic portion provided on both side walls of the guide cylinder and facing each of the magnets, and an eddy current based on a magnetic field from the magnet. In the eddy current reduction device that generates a braking force on the braking disk, both side walls of the guide cylinder are formed of a thick stainless steel plate that is a ferromagnetic material, and a ferromagnetic portion of the both side walls facing the magnet is provided. Non-magnetic or weak magnetic by quenching from the high temperature state by partially solutionizing the non-opposed parts,
An eddy current reduction device, wherein a narrow radial groove is provided at a boundary between the nonmagnetic or weak magnetic portion and the ferromagnetic portion of the both side walls facing 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 of the inner and outer peripheral edges of the braking disk not facing the ferromagnetic portion. .