JP2003047232A - Eddy current decelerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eddy current decelerator whose magnet support cylinder can be made at a low cost and which can use a limited space efficiently for the arrangement of magnets. SOLUTION: A guide cylinder 6, made of nonmagnetic material and having a hollow part 20 with a rectangular cross-section in it, is placed in a brake drum 15 made of conductive material and coupled with a rotary shaft 2. A magnet support cylinder 25 having a large number of magnets 21 is supported in the hollow part 20 of the guide cylinder 6 so as to be movable axially. A braking torque is generated in the brake drum 15 by eddy currents induced by magnetic fields reaching the brake drum 15 from the magnets 21 via the outer cylinder 6a of the guide cylinder 6. In the magnet support cylinder 25, the magnets 21 whose circumferential ends are poles and ferromagnetic members 22 are alternately arranged circumferentially between a pair of left and right annular plates 23 and 24 made of nonmagnetic material and both the pair of plates 23 and 24 are tied with each other by bolts laid in the same direction as the rotary shaft 2.

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 reduction device for assisting a friction brake of a vehicle, and more particularly, to increase a braking ability by accommodating a large number of magnets in a limited inner space of a guide cylinder. The present invention relates to the eddy current speed reducer.

[0002]

2. Description of the Related Art In a conventional eddy current speed reducer, a guide cylinder made of a non-magnetic material is arranged inside a braking drum made of a conductor.
A large number of permanent magnets (hereinafter, simply referred to as magnets) are coupled to the outer peripheral surface of the magnet supporting cylinder made of a magnetic material housed in the inner space of the guide cylinder at equal circumferential intervals, and the outer cylinder part of the guide cylinder ( The magnetic poles facing the inner peripheral surface of the braking drum via the ferromagnetic member (pole piece) are arranged so as to be alternately different in the circumferential direction. When the magnet supporting cylinder is pushed into the braking drum during braking, the magnetic field from the magnet forms a magnetic circuit between the braking drum and the magnet supporting cylinder. When the rotating braking drum traverses the magnetic field from the magnet, a braking force based on eddy current is generated in the braking drum. During non-braking, the magnet support cylinder is retracted from the inside of the braking drum, and the outer surface of the magnet is covered with a ferromagnetic material so that the magnetic field does not reach the braking drum. In the above-mentioned eddy current speed reducer, the ferromagnetic member is restricted in length and shape in order to avoid interference between the braking drum and the ferromagnetic member (pole piece). Moreover, the space limited to the arrangement of the magnets is not effectively used.

In the eddy current speed reducer disclosed in FIGS. 8 to 9 of Japanese Patent Laid-Open No. 2001-8436, a guide cylinder made of a non-magnetic material having an inner space with a rectangular cross section is arranged inside the braking drum. The inner half of a large number of magnets arranged alternately in the circumferential direction and the ferromagnetic member are joined by means such as adhesion to a support tube having a groove-shaped cross section housed in the inner space of the outer side of the magnet and the ferromagnetic member. The end portion faces the inner peripheral surface of the braking drum through the outer cylindrical portion of the guide cylinder.

In the above-mentioned eddy current speed reducer, a large number of magnetic poles are opposed to the inner peripheral surface of the braking drum, so that a large braking ability can be obtained especially in the low speed range of the braking drum. Is difficult to mount, and if the axial dimension of the braking drum is increased in order to obtain a large braking ability, the coupling strength between a large number of magnets and the ferromagnetic member with respect to the support cylinder becomes a problem.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an eddy current speed reducer in which the manufacturing cost of the magnet supporting cylinder is low and the magnet can be effectively used in the limited inner space of the guide cylinder. It is in.

Another object of the present invention is to easily magnetize each magnet, and even if the axial dimension of the magnet support cylinder is lengthened according to the braking drum, a large number of magnets and ferromagnetic members are provided for the support cylinder. An object of the present invention is to provide an eddy current speed reducer having no problem with the coupling strength of the above.

[0007]

In order to solve the above-mentioned problems, the structure of the present invention is a guide made of a non-magnetic material having a hollow section having a rectangular cross section inside a braking drum made of a conductor coupled to a rotating shaft. A cylinder is arranged, a magnet support cylinder having a large number of magnets is supported in the inner space of the guide cylinder so as to be movable in the axial direction, and a magnetic field extending from the magnet to the braking drum via the outer cylinder of the guide cylinder, In the eddy current speed reducer in which the braking drum generates a braking torque based on an eddy current, the magnet support cylinder is a pair of left and right annular plates made of a non-magnetic material, and a magnet having a magnetic pole at its circumferential end is a strong member. The magnetic members and the magnetic members are alternately arranged in the circumferential direction and fastened by bolts in the same direction as the rotating shaft.

Further, according to the structure of the present invention, a guide cylinder made of a non-magnetic material having a hollow section having a rectangular cross section is arranged inside a braking drum made of a conductor coupled to a rotary shaft, and the inner hollow section of the guide tube is arranged. A stationary magnet support cylinder having a large number of magnets and a magnet support cylinder rotatable forward and reverse, and the braking drum is swirled by a magnetic field extending from the magnet to the braking drum through the outer cylinder of the guide cylinder. In an eddy current reduction device that generates a braking torque based on an electric current, each magnet support cylinder includes a pair of left and right annular plates made of a non-magnetic material, and the magnet and the ferromagnetic member whose circumferential ends form a magnetic pole. It is characterized in that they are arranged alternately in the circumferential direction and fastened by bolts in the same direction as the rotating shaft.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a ferromagnetic member (pole piece) is joined to both circumferential end portions forming the magnetic poles of a large number of magnets to form an annular body. A pair of left and right annular plates consisting of are laminated and fastened with a plurality of axial bolts to form a magnet support cylinder. The ferromagnetic members arranged in an annular shape as a whole have a structure in which a magnetic field is generated from both the outer peripheral portion and the inner peripheral portion, and it is easy to magnetize the magnet after forming the magnet supporting cylinder. Even if the axial dimension is increased, a high coupling strength between a large number of magnets and the ferromagnetic member with respect to the support cylinder can be obtained by the plurality of axial bolts.

During braking, when the magnet support cylinder is moved in the axial direction and pushed into the inside of the braking drum, the ferromagnetic member (pole piece) of the magnet support cylinder becomes a ferromagnetic member or a non-magnetic member of the outer cylinder portion of the guide cylinder. A magnetic field is applied to the braking drum through the thin plate. When a rotating braking drum traverses the magnetic field from a ferromagnetic member (pole piece),
A braking force based on the eddy current is generated in the braking drum. During non-braking, the magnet support cylinder is retracted to the outside of the braking drum.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an eddy current speed reducer according to the present invention comprises a braking drum 15 made of a conductor such as iron, a guide cylinder 6 made of a non-magnetic material, and a magnet support cylinder 25.
The braking drum 15 having the cooling fins 15a has a base end portion,
It is connected to the tips of a large number of spokes 16 that extend radially from the boss portion 4 connected to the rotating shaft 2. The tip of the braking drum 15 is opened in a conical shape. On both ends of the inner peripheral surface of the braking drum 15, an annular good conductor 13, such as copper, having a small electric resistance,
13a is coupled. The guide cylinder 6 is arranged inside the braking drum 15 and is supported by a non-rotating portion of the vehicle. The guide cylinder 6 has a thick outer cylinder portion 6a made of a magnetic material, and an outer cylinder portion 14 made of a non-magnetic thin plate.
The inner cylindrical portion 6c made of a non-magnetic material and both end walls 6b, 6d made of a non-magnetic material define an inner hollow portion 20 having a rectangular cross section. The thick outer cylinder portion 6 a has a conical surface 36 formed at a portion facing the conical tip portion of the braking drum 15. The conical portion formed at the end of the outer cylindrical portion 14 made of a non-magnetic thin plate is superposed on the conical surface 36 and is joined by the bolt 12.

The magnet support cylinder 25 is supported by the actuator A in the inner space 20 of the guide cylinder 6 so as to be movable in the axial direction.
The magnet support cylinder 25 is composed of a pair of left and right annular plates 23, 24 made of a non-magnetic material such as aluminum or stainless steel, and a large number of magnets 21 and ferromagnetic members 22 alternately coupled in the circumferential direction. . In the actuator A, a piston 32 is fitted in a cylinder 31 to define fluid chambers 33 and 34, and a magnet support cylinder 25 is connected to a rod 7 extending from the piston 32 to the inner space 20 through the end wall 6b. The rod 7 of the actuator A has a small diameter portion on the front end side, and a bolt 12 to be described later.
It is preferable that the nut penetrates through one of the through holes, and a nut is screwed to the tip portion of the rod 7 for fastening.

As shown in FIG. 2, a block-shaped magnet 21 is provided.
A ferromagnetic member 22 having a trapezoidal or wedge-shaped side cross-section is sandwiched between both end faces in the circumferential direction of the magnetic pole face, that is, the magnetic pole faces.
2 is an annular plate 23, 2 by means of axial bolts 26 and nuts.
It is concluded in 4. The ferromagnetic member 22 is formed with a projecting piece that projects radially outward from between the annular plates 23 and 24 and that faces the outer cylindrical portion 14. When the opposite magnetic poles of the pair of magnets 21 arranged in the circumferential direction have the same polarity, as shown in FIGS. 2 and 3, the polarities of the protrusions of the ferromagnetic member 22 are alternately arranged in the circumferential direction. .

When the magnet support cylinder 25 is pushed into the braking drum 15 as shown in FIG. 1, each magnet 21 exerts a magnetic field on the braking drum 15 via the ferromagnetic member 22 and the outer cylinder portion 14. When the rotating braking drum 15 traverses the magnetic field from the ferromagnetic member 22, eddy current-based braking torque is generated.
At this time, a magnetic circuit z (FIG. 2) is formed between the magnet 21, the ferromagnetic member 22 and the braking drum 15.

In the embodiment shown in FIG. 4, a groove 21b extending in the axial direction is provided on the outer surface of the ferromagnetic member 22 facing the outer cylindrical portion 14 or the inner peripheral surface of the braking drum 15, and each magnet 21 is provided with a braking drum. The magnetic flux density of the magnetic circuit formed between the magnetic poles 15 and 15 is increased. The cross-sectional shape of the groove 21b on the outer surface of the ferromagnetic member 22 is not limited to the rectangular shape, and may be a triangular shape as shown in FIG.

In the embodiment shown in FIG. 6, the magnets 21 of the magnet support cylinder 25 shown in FIG. 2 are halved (the array pitches of the magnets 21 are doubled), and the magnets 21 are attached to both end faces (pole faces) in the circumferential direction. The ferromagnetic members 22 are coupled to each other, and an empty space is provided between the adjacent ferromagnetic members 22 or a spacer 21a made of a non-magnetic material is provided. The braking torque is slightly weaker, but it helps to reduce the weight.

As shown in FIG. 7, a pair of left and right annular plates 2
By making the radial dimension of 3, 24 the same as that of the ferromagnetic member 22, the coupling strength between the annular plates 23, 24 and the ferromagnetic member 22 can be increased.

In the embodiment shown in FIG. 8, a bolt 43 is formed radially from the inside of the recess 42 formed on the outer surface of the ferromagnetic member 22.
Is screwed into a cylindrical body 45 made of a non-magnetic material or a magnetic material, and a plurality of axial bolts 41, 44 and nuts are used to connect the ferromagnetic member 22, the magnet 21, and the cylindrical body 45 to a pair of annular plates 23. , 24. Annular plate 23,
The coupling strength between the magnet 24 and the ferromagnetic member 22 is further increased, and there is no problem even if the axial dimension of the magnet support cylinder 25 is lengthened.

In the above embodiment, the pair of magnets 21 arranged in the circumferential direction have opposite magnetic poles having the same polarity.
As shown in, even if the polarities of all the magnets 21 are arranged in the same direction in the circumferential direction, the same effect as that of the embodiment of FIGS. Further, when the outer cylinder portion 14 of the guide cylinder 6 is cast from aluminum, a ferromagnetic plate 9 facing each ferromagnetic member 22 may be cast into the outer cylinder portion 14 at equal intervals in the circumferential direction. .

The present invention can also be applied to an eddy current reduction device that switches between braking and non-braking by rotating the magnet support cylinder forward and backward. As shown in FIG. 10, a movable magnet support cylinder 25 and a stationary magnet support cylinder 25A are housed inside the guide cylinder 6. The movable magnet support cylinder 25 includes a magnet 21 and a ferromagnetic member 22 inside a U-shaped frame in which a pair of left and right annular plates 23 and 24 made of a non-magnetic material such as aluminum and a cylinder body 29 are integrally formed. Are alternately arranged side by side in the circumferential direction, and nuts are screwed into and fastened to bolts (not shown) penetrating the annular plate 23, the ferromagnetic member 22, and the annular plate 24. The ferromagnetic member 22 projects radially outward from the frame and faces the outer cylinder portion 14 made of a non-magnetic thin plate. The magnet support cylinder 25 is 1 on the left and right
The pair of bearings 28 are supported by the inner cylindrical portion 6c so as to be able to rotate forward and backward. The actuator A is supported by the end wall 6b, and the arm 18 protruding from the annular plate 23 to the outside through the opening of the end wall 6b is connected to the piston rod 7.

The stationary magnet support cylinder 25A accommodates the magnets 21 and the ferromagnetic members 22 alternately arranged inside a frame formed by the annular plate 23 made of a non-magnetic material, the end wall 6d and the inner cylinder portion 6c. The annular plate 23 to the ferromagnetic member 22 and the end wall 6d.
A nut is screwed into a bolt 26 penetrating through and is fastened.
In the illustrated embodiment, the left and right ferromagnetic members 22 are axially extended so as to approach each other at the portions projecting from the frame.
Other configurations are similar to those shown in FIG.

When the magnets 21 arranged in the axial direction have different polarities (FIG. 10), the two ferromagnetic members 22 of the movable magnet supporting cylinder 25 and the two ferromagnetic members 2 of the stationary magnet supporting cylinder 25A.
A short-circuiting magnetic circuit is generated between the two and the magnetic field is not applied to the braking drum 15.

On the other hand, during braking, the magnet support cylinder 25 is moved to the magnet 21.
When it is rotated by an amount corresponding to the arrangement pitch of, the polarities of the ferromagnetic members 22 arranged in the axial direction become the same, and the two ferromagnetic members 22 arranged in the circumferential direction of the movable magnet supporting cylinder 25 and the stationary magnet supporting cylinder 25A. Between the two ferromagnetic members 22 arranged in the circumferential direction,
A magnetic circuit z (see FIG. 2) is created which bypasses the braking drum 15. When the rotating braking drum 15 traverses a magnetic field that extends from the magnet 21 of each magnet supporting cylinder 25, 25A through the ferromagnetic member 22 and the outer cylinder portion 14 to the braking drum 15, the braking torque based on the eddy current is applied to the braking drum 15 by the braking torque. Occur. A good conductor 1 made of copper or the like arranged on both ends of the inner peripheral surface of the braking drum 15.
Reference numerals 3 and 13a promote the axial spreading of the eddy current generated in the braking drum 15 and enhance the braking ability.

In the embodiment shown in FIG. 11, the outer cylinder portion 6a, the inner cylinder portion 6c and both end walls 6b and 6d of the guide cylinder 6 are made of a non-magnetic material such as aluminum, and the outer cylinder portion 6a is provided with each ferromagnetic member. The ferromagnetic plate 9 facing 22 is coupled. Specifically, when casting the outer cylinder portion 6a of the guide cylinder 6 from aluminum, the ferromagnetic plate 9 is cast. Other configurations are the same as those shown in FIG. 10, and similar operational effects are obtained.

[0025]

As described above, according to the present invention, a ferromagnetic member is joined to both end surfaces of a magnet whose circumferential end has a magnetic pole between a pair of left and right annular plates whose magnet support cylinder is made of a non-magnetic material. Since it is fastened with a plurality of axial bolts sandwiching the object, it is easy to magnetize the magnet after forming the magnet supporting cylinder, and even if the axial dimension of the magnet supporting cylinder is lengthened, a plurality of magnets can be magnetized. With the axial bolts, high coupling strength between a large number of magnets and the ferromagnetic member with respect to the magnet support cylinder can be obtained.

[Brief description of drawings]

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

FIG. 2 is a side sectional view of the eddy current reduction device.

FIG. 3 is a plan cross-sectional view showing a magnet support cylinder of the same eddy current speed reducer in a circumferential direction.

FIG. 4 is a side sectional view of a magnet support cylinder according to a partially modified embodiment of the present invention.

FIG. 5 is a side sectional view of a magnet support cylinder according to another partially modified embodiment of the present invention.

FIG. 6 is a side sectional view of a magnet support cylinder according to another partially modified embodiment of the present invention.

FIG. 7 is a side sectional view of a magnet support cylinder according to another partially modified embodiment of the present invention.

FIG. 8 is a side sectional view of a magnet support cylinder according to another partially modified embodiment of the present invention.

FIG. 9 is a side sectional view of a magnet support cylinder according to another partially modified embodiment of the present invention.

FIG. 10 is a front sectional view of another type of eddy current speed reducer to which the present invention is applied.

FIG. 11 is a front sectional view of another type of eddy current speed reducer to which the present invention is applied.

[Explanation of symbols]

A: Actuator z: Magnetic circuit 2: Rotating shaft 3:
Spokes 4: Boss part 6: Guide cylinder 6a: Outer cylinder part 6b: End wall 6c: Inner cylinder part 6d: End wall 7: Rod 9: Ferromagnetic plate 12: Bolt 13: Good conductor 13a: Good conductor 14: Outer cylinder part 1
5: Braking drum 15a: Cooling fin 16: Spoke 18: Arm 20: Inner space 21: Magnet 21a: Spacer 21b: Groove 22: Ferromagnetic member 23: Annular plate
24: Annular plate 25: Magnet support cylinder 25A: Magnet support cylinder 26: Bolt 26a: Hole 28: Bearing 29: Cylindrical body 31: Cylinder 32: Piston 33: Chamber 34: Chamber 36: Conical surface 38: Bolt 4
1: Bolt 42: Recess 43: Bolt 44: Bolt 45: Cylindrical body 46: Bolt

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Makoto Ogawa             Isuzu Motors, 8 Soil Shelf, Fujisawa City, Kanagawa Prefecture             Fujisawa Factory Co., Ltd. (72) Inventor Shin Kobayashi             Isuzu Motors, 8 Soil Shelf, Fujisawa City, Kanagawa Prefecture             Fujisawa Factory Co., Ltd. (72) Inventor Masaki Asano             Isuzu Motors, 8 Soil Shelf, Fujisawa City, Kanagawa Prefecture             Fujisawa Factory Co., Ltd. F term (reference) 5H649 BB02 GG09 GG13 GG16 HH04                       HH06 HH13 HH16 JK02 JK04                       PP02 PP13

Claims (7)

[Claims] 1. A guide cylinder made of a non-magnetic material having an inner space with a rectangular cross section is arranged inside a braking drum made of a conductor connected to a rotating shaft, and a large number of magnets are provided in the inner space of the guide cylinder. An eddy current reduction device that supports a magnet supporting cylinder that is provided so as to be movable in the axial direction, and that causes the braking drum to generate a braking torque based on an eddy current by a magnetic field that extends from the magnet to the braking drum via an outer cylinder portion of the guide cylinder. In the magnet supporting cylinder, the magnets and the ferromagnetic members whose circumferential ends are magnetic poles are alternately arranged in a circumferential direction between a pair of left and right annular plates made of a non-magnetic material, and the magnet supporting cylinders are arranged in the same direction as the rotating shaft. An eddy current speed reducer characterized by being fastened with bolts. 2. A guide cylinder made of a non-magnetic material having an inner space with a rectangular cross section is arranged inside a braking drum made of a conductor coupled to a rotating shaft, and a large number of magnets are provided in the inner space of the guide cylinder. A braking torque based on an eddy current is applied to the braking drum by a magnetic field that supports a stationary magnet supporting cylinder and a magnet supporting cylinder that can rotate forward and backward, and that extends from the magnet to the braking drum through the outer cylindrical portion of the guide cylinder. In the eddy current decelerating device, the magnet support cylinders are arranged between a pair of left and right annular plates made of a non-magnetic material, and the magnets whose end portions in the circumferential direction form magnetic poles and the ferromagnetic members are alternately arranged in the circumferential direction. An eddy current reduction device characterized by being fastened with a bolt in the same direction as the rotating shaft. 3. A cylindrical body made of a non-magnetic material is coupled between a pair of left and right annular plates made of the non-magnetic material, and the magnets and the ferromagnetic members are alternately arranged on the outer peripheral surface of the cylindrical body in the circumferential direction. The eddy current reduction device according to claim 1, wherein the ferromagnetic member is fastened to the cylindrical body by a radial bolt. 4. The eddy current decelerating device according to claim 1, wherein the magnetic poles of the pair of magnets contacting the circumferential ends of the ferromagnetic members have the same polarity. 5. The eddy current decelerating device according to claim 1, wherein every other one of the magnets arranged in the circumferential direction is removed. 6. The eddy current speed reducer according to claim 1, wherein an axial groove is provided on an outer surface of the ferromagnetic member facing the outer cylinder portion of the guide cylinder. 7. The eddy current reduction device according to claim 1, wherein the outer cylinder portion of the guide cylinder is made of a non-magnetic plate that is thinner than the other parts of the guide cylinder.