JPH0767203B2 - Eddy current type speed reducer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an eddy current type speed reducer for assisting a friction brake of a large vehicle, and particularly to generate an intermediate braking torque not only in a conventional braking position and a non-braking position but also in an intermediate braking position. The present invention relates to an eddy current type speed reducer.

[0002]

2. Description of the Related Art In an eddy current type speed reducer disclosed in Japanese Patent Application No. 2-201817, an inner space made of a non-magnetic material and having a rectangular cross section is provided between a pair of braking disks coupled to a rotating shaft. An annular fixed frame is provided, and a large number of ferromagnetic plates are coupled to both end walls of the fixed frame at equal intervals in the circumferential direction, so that a pair of inner and outer magnet support wheels can be relatively rotated in the inner space of the fixed frame. Supported. A large number of permanent magnets (hereinafter simply referred to as magnets) are arranged on each magnet support ring so that the polarities of the respective ferromagnetic plates are alternately different in the circumferential direction.

At the time of braking, when the directions of the magnets of the pair of inner and outer magnet supporting wheels sandwiched between the pair of ferromagnetic plates are reversed,
A short-circuiting magnetic circuit occurs between the pair of ferromagnetic plates and does not exert a magnetic field on the braking disc. On the other hand, at the time of braking, if the magnets of the pair of inner and outer magnet supporting wheels sandwiched between the pair of ferromagnetic plates are made to have the same direction, the magnets adjacent in the circumferential direction penetrate the ferromagnetic plate and reach the braking disc. When a rotating braking disc forms a magnetic circuit and crosses a magnetic field, an eddy current flows through the braking disc, and the braking disc receives a braking torque.

However, the above-mentioned eddy current type speed reducer merely switches the operating position between non-braking and braking by providing a rotational differential between the pair of inner and outer magnet supporting wheels by the arrangement pitch of the magnets. Therefore, the intermediate braking torque cannot be applied to the braking disc at the intermediate braking position.

When a vehicle travels on a long downhill, a braking torque suitable for a road gradient and a vehicle speed is required, and when an intermediate braking torque is sufficient, it is vortex to continuously brake with the intermediate braking torque. The amount of heat generated by the electric current is small, there is no fear that the braking disc will overheat, and driving becomes easier.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide an intermediate braking position between a braking position and a non-braking position for a pair of inner and outer magnet supporting wheels in order to satisfy the above-mentioned requirements. An object of the present invention is to provide an eddy current type speed reducer in which a magnet of one magnet supporting wheel applies an intermediate braking torque to a braking disc.

[0007]

In order to achieve the above-mentioned object, the structure of the present invention has a pair of braking discs connected to a rotary shaft, and an inner space made of a non-magnetic material and having a rectangular cross section. An annular fixed frame is arranged, a large number of ferromagnetic plates are connected to both end walls of the fixed frame at equal intervals in the circumferential direction, and a pair of inner and outer magnet support wheels are supported in the inner space of the fixed frame so as to be relatively rotatable. However, in each magnet support wheel, two permanent magnets are arranged on each ferromagnetic plate so as to face each other with a circumferential interval, and the polarities of the two permanent magnets are different from each other in the circumferential direction.

[0008]

An annular fixed frame having a rectangular cross section and made of a non-magnetic material is disposed between a pair of braking discs, and a plurality of ferromagnetic plates facing the braking discs are provided on both end walls of the fixing frame. Are arranged at equal intervals in the circumferential direction. A pair of inner and outer magnet support wheels are supported in the inner space of the fixed frame so as to be relatively rotatable. In each magnet support wheel, two magnets are arranged on each ferromagnetic plate so as to face each other with a circumferential interval, and the polarities with respect to the ferromagnetic plates are different by two in the circumferential direction. In this case, the two magnets of one magnet support ring may be integrated into one.

During non-braking, two sets of magnets of the inner and outer magnet supporting wheels are sandwiched between a pair of ferromagnetic plates of the fixed frame, and two magnets of the outer magnet supporting wheel and two magnets of the inner magnet supporting wheel. The directions (polarity) of the two magnets are opposite to each other. Inside and outside 2
The pair of magnets forms a short-circuit magnetic circuit with the pair of ferromagnetic plates and does not exert a magnetic field on the braking disc.

During semi-braking, when one magnet supporting wheel is rotated by an amount corresponding to the arrangement pitch of the magnets, the two magnets of the rotated magnet supporting wheel are sandwiched between the pair of ferromagnetic plates of the fixed frame. Reverse to each other and form a short-circuit magnetic circuit between the pair of ferromagnetic plates. However, the two magnets of the magnet support ring that are sandwiched between a pair of ferromagnetic plates and do not rotate have the same direction, and two magnets that are adjacent in the circumferential direction pass through the two pairs of ferromagnetic plates and the braking circles. A magnetic circuit is formed between the plate and the plate. When the rotating braking disc traverses the magnetic field, eddy currents flow in the braking disc and the braking disc receives an intermediate braking torque.

At the time of full braking, when one magnet supporting wheel is rotated from the non-braking position by two pitches of the magnet arrangement pitch, the two magnet supporting wheels of the inner and outer sides are sandwiched between the pair of ferromagnetic plates of the fixed frame. The magnets (all) in the set have the same orientation, and two sets of magnets adjacent to each other in the circumferential direction form a magnetic circuit between the pair of magnets and two pairs of ferromagnetic plates and the braking disc. When the rotating braking disc traverses the magnetic field, eddy currents flow in the braking disc and the braking disc receives braking torque.

[0012]

1 is a front sectional view showing a lower half portion of an eddy current type speed reducer according to the present invention, and FIG. 2 is a side sectional view of the same eddy current type speed reducer. The eddy current type speed reducer according to the present invention includes, for example, a braking disc 3 formed of a pair of conductors coupled to an output rotary shaft 2 of a vehicle transmission, and a non-magnetic body disposed between the braking discs 3. Fixed frame 5 consisting of
And a pair of inner and outer magnet supporting wheels 8 and 10 rotatably supported in the inner space. The braking disc 3 has a disc portion having an air passage 3c integrally connected to a spoke 3b radially extending from a boss 3a fixed to the rotary shaft 2 by a spline.

The fixed frame 5 is an annular one having an inner space with a rectangular cross section, and is specifically constructed by connecting an annular end plate 5c to a cylindrical body having a C-shaped cross section. Fixed frame 5 is boss 5
The boss 5a is formed integrally with the spoke 5b extending in the radial direction from a, and the boss 5a is supported by the rotating shaft 2 by the bearing 4. The fixed frame 5 is fixed to the gear box of the transmission by any suitable means. A large number of openings are provided at equal intervals in the circumferential direction on both end walls of the fixed frame 5, and a ferromagnetic plate (pole piece) 6 is fitted and fixed in each opening. Preferably, the ferromagnetic plate 6 is cast during molding of the fixed frame 5.

A magnet support wheel 8 for supporting a large number of magnets 12.
Is rotatably supported by the bearing 7 in the inner space of the fixed frame 5. The magnet support wheel 10 has a bearing 9 on the outer peripheral wall of the magnet support wheel 8.
Is rotatably supported by. A thin sliding plate 14 impregnated with lubricating oil is coupled to both end surfaces of the magnet supporting wheels 8 and 10,
And it is slidably contacted with the ferromagnetic plate 6.

As shown in FIG. 2, the magnet support ring 8 made of a non-magnetic material is coupled with a large number of magnets 12. Specifically, the magnets 12 are arranged so as to face each of the ferromagnetic plates 6 by two and have polarities different from each other by two in the circumferential direction. Preferably, the magnet 12 is cast around the magnet support wheel 8. Partial gear 18a formed on the inner peripheral wall of the magnet support wheel 8
Further, the small gear 15a of the electric motor 16a fixed to the fixed frame 5 is meshed with the magnet supporting wheel 8 so that the magnet supporting wheel 8 can be rotated forward and backward by an amount corresponding to the arrangement pitch of the magnets 12.

The magnet support wheel 10 also has a large number of magnets 13 coupled thereto. The small gear 15 of the electric motor 16 fixed to the fixed frame 5 is meshed with the partial gear 18 formed on the outer peripheral wall of the magnet supporting wheel 10, so that the magnet supporting wheel 10 can be rotated forward and backward by the arrangement pitch of the magnets 13. To be done. However, the magnet support wheels 8, 1
It suffices that one of 0s can rotate by 2 pitches of the arrangement pitch of the magnets. Each ferromagnetic plate 6 has two pairs of inner and outer magnets 12, 1
It is a fan-shaped one that covers 3.

Next, the operation of the eddy current type speed reducer according to the present invention will be described. While the pair of braking discs 3 rotates together with the rotary shaft 2, as shown in FIGS. 1 and 2, the direction (polarity) of the two magnets 12 and 13 with respect to each ferromagnetic plate 6 is set when the braking is not performed. ) Are opposite to each other. Two sets of magnets 12, 1
3 forms a short-circuit magnetic circuit indicated by a chain line between the pair of ferromagnetic plates 6 and does not exert a magnetic field on the braking disc 3.

As shown in FIG. 3, when the magnet support wheel 10 is rotated counterclockwise by an electric motor 16 by a pitch corresponding to the arrangement of the magnets during the half braking, the orientation of the two magnets 13 with respect to each ferromagnetic plate 6 is changed. Opposite of each other, the two magnets 13 form a short-circuit magnetic circuit with the pair of ferromagnetic plates 6, as shown by the chain line in FIG. However, the directions of the two magnets 12 with respect to each ferromagnetic plate 6 are the same, and as shown by the chain line in FIG. 5, two magnets 12 adjacent in the circumferential direction pass through two pairs of ferromagnetic plates 6 and form one pair. A magnetic circuit is formed between the braking disc 3 and the braking disc 3. When the rotating braking disc 3 crosses the magnetic field, an eddy current flows in the braking disc 3 and the braking disc 3 receives an intermediate braking torque.

As shown in FIG. 6, at the time of full braking, the electric motor 16
When the magnet supporting wheel 8 is rotated clockwise from the semi-braking position by a, the polarity of the two magnets 12 and 13 with respect to each ferromagnetic plate 6 becomes the same. Therefore, as in the case of the magnet 12 shown in FIG.
Also applies a magnetic field to the braking disc 3 via the ferromagnetic plate 6. When the rotating braking disc 3 crosses the magnetic field, an eddy current is generated in the braking disc 3 and the braking disc 3 receives the total braking torque.

In the above-mentioned embodiment, even if the magnets 12 of the stationary magnet support wheel 8 are integrally formed of magnets of the same polarity which are adjacent to each other in the circumferential direction, the same effect can be obtained.

In the embodiment shown in FIG. 7, the circumferential dimension of the magnet 12a of the stationary magnet support ring 8 is set to the movable magnet support ring 10.
Of the two magnets 13 (when developed in the circumferential direction), the polarities of the magnets 12a with respect to the ferromagnetic plate 6 are arranged so as to be alternately different in the circumferential direction. In the illustrated semi-braking position, the polarities of the two magnets 13 facing each ferromagnetic plate 6 are opposite to each other, so that a short-circuit magnetic circuit is formed between the pair of ferromagnetic plates 6 and the braking disc 3 Does not exert a magnetic field on However, FIG.
As shown in FIG. 5, the magnets 12a adjacent to each other in the circumferential direction form a magnetic circuit indicated by a chain line between the magnets 12a which are adjacent to each other via the ferromagnetic plate 6 and the pair of braking discs 3, and the rotating braking disc 3 has an intermediate braking torque. Exert.

In the embodiment shown in FIG. 9, contrary to the embodiment shown in FIG. 7, the magnet support wheel 10 is immovable, and the magnets 13a corresponding to the two magnets 12 of the magnet support wheel 8 are integrated into one. To do. In the illustrated semi-braking position, the magnets 13a adjacent to each other in the circumferential direction of the magnet support wheel 10 form a magnetic circuit similar to FIG. 8 between the magnet 13a and the pair of braking discs 3 via the ferromagnetic plate 6 to rotate. An intermediate braking torque is exerted on the braking disc 3 that operates.

[0023]

As described above, according to the present invention, a pair of inner and outer magnet support wheels are rotatably supported by the inner space of a fixed frame having a large number of ferromagnetic plates on both end walls at equal intervals in the circumferential direction. However, since each magnet supporting wheel has two magnets connected to each ferromagnetic plate and two magnets are connected so as to have different polarities in the circumferential direction, the magnets of the inner and outer magnet supporting wheels for each ferromagnetic plate are connected to each other. Three different arrangement patterns occur in the non-braking position, a semi-braking position in which only one magnet of the magnet supporting wheel exerts a braking torque on the braking disc, and magnets of both the inner and outer magnet supporting wheels brake the braking disc. Operates in all braking positions that exert torque.

For example, when traveling on a long downhill, continuous braking can be performed with an intermediate braking torque suitable for the road gradient and the vehicle speed, driving becomes easy, and there is no fear that the braking disc will overheat.

[Brief description of drawings]

FIG. 1 is a front sectional view of an eddy current type speed reducer according to the present invention.

FIG. 2 is a side sectional view showing a state of a magnet supporting wheel of the same eddy current type speed reducer when not braking.

FIG. 3 is a side cross-sectional view showing a state of a magnet support wheel of the same eddy current type speed reducer during half braking.

FIG. 4 is a plan cross-sectional view showing the outer magnet support ring in the circumferential direction.

FIG. 5 is a plan cross-sectional view showing the inner magnet support ring in the circumferential direction.

FIG. 6 is a side sectional view showing a state of the magnet support wheels of the same eddy current type speed reducer at the time of full braking.

FIG. 7 is a side sectional view showing a state of a magnet supporting wheel during half braking of the eddy current type speed reducer according to the second embodiment of the present invention.

FIG. 8 is a plan cross-sectional view showing the inner magnet support ring in the circumferential direction.

FIG. 9 is a side sectional view showing a state of a magnet supporting wheel during half braking of an eddy current type speed reducer according to a third embodiment of the present invention.

[Explanation of symbols]

2: Rotating shaft 3: Braking disc 5: Fixed frame 6: Ferromagnetic plate 8, 10: Magnet support ring 12, 13: Permanent magnet

Claims (2)

[Claims] 1. Between a pair of braking discs connected to a rotating shaft,
An annular fixed frame made of a non-magnetic material and having a rectangular cross section is arranged, and a large number of ferromagnetic plates are connected to the both end walls of the fixed frame at equal intervals in the circumferential direction. An inner and outer pair of magnet support wheels are supported so as to be rotatable relative to each other, and two permanent magnets are opposed to each ferromagnetic plate at a circumferential interval and the polarities of the ferromagnetic plates are circumferential. 2. An eddy current type speed reducer characterized in that two different arrangements are provided. 2. Two magnets of the same polarity which are adjacent to each other on one magnet supporting wheel.
The eddy current type speed reducer according to claim 1, wherein two permanent magnets are integrated into one.