JP2000069739A - Eddy current reducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an eddy current reduction gear inexpensively by jointing a thin stripe plate having heat dissipation fins formed by raising the thin plate at an interval in the longitudinal direction to the outer circumferential surface of a brake drum thereby enhancing heat dissipation efficiency, preventing deterioration of fuel consumption and decreasing air resistance of the heat dissipation fins. SOLUTION: In order to reduce machining cost of heat dissipation fins 2b for a brake drum 2 while enhancing heat dissipation performance, a thin stripe plate having heat dissipation fins 32c is wound around the straight cylindrical brake drum 2 or a heat dissipation tube 32 made of a thin stripe plate is fitted thereto. The heat dissipation tube 32 is made by cutting three sides of a large number of plates from a thin stripe plate 32a at a specified interval in the longitudinal direction and then bending one remaining side at right angle. More specifically, the heat dissipation fins 32c are formed by bending a raised piece from an opening 32b perpendicularly to the plate surface. The heat dissipation tube 32 is formed by bending the thin plate 32a tubularly.

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 mainly using a permanent magnet or an electromagnet for assisting a friction brake of a vehicle, and more particularly to an eddy current reduction device which is easy to process a braking drum and has excellent heat dissipation. is there.

[0002]

2. Description of the Related Art For example, in a conventional eddy current reduction device of the type in which a magnet support cylinder is switched between braking and non-braking by rotating the magnet support cylinder forward and backward by an arrangement pitch of magnets, a magnet support cylinder shown in FIG. The guide drum 4 contains the guide cylinders 16 and 17 and the braking drum 2 that covers the outer peripheral surface of the guide cylinder 4 shown in FIG. The guide cylinder 4 having an inner space with a rectangular cross section is made of a non-magnetic material, and a number of ferromagnetic plates 5 are integrally connected to the outer cylinder at equal intervals in the circumferential direction. The cylinder 16 and the stationary magnet support cylinder 17 are supported. Magnets 6, 7 entirely facing the ferromagnetic plate 5 are coupled to the support cylinders 16, 17. The polarities of the magnets 6 and 7 facing the ferromagnetic plate 5 are alternately arranged in the circumferential direction. The guide cylinder 4 has a mounting flange 4d coupled to the left end supported by a non-rotating portion of the vehicle body.

An actuator 22a is supported on the left end of the guide cylinder 4 to rotate the movable magnet support cylinder 16 forward and backward by the pitch of the arrangement of the magnets 6. The actuator 22a has a fluid chamber defined at both ends by inserting a piston into the cylinder 23a, and an outer end of a rod connected to the piston is connected to the magnet support cylinder 16 via an arm. Actuator 22a
The fluid chambers are connected to conduits 34 and 35 for introducing pressurized air. When pressurized air is introduced from an air tank (not shown) to one of the conduits 34 and 35 through a directional switching valve, the pistons are used. A non-braking position in which the magnet support cylinder 16 is rotated forward and reverse, and the polarities of the magnets 6 and 7 facing the common ferromagnetic plate 5 are different;
The polarity of the magnets 6 and 7 switches to the same braking position. When the rotating braking drum 2 crosses the magnetic field from the magnets 6 and 7 at the braking position of the magnet support cylinder 16, a braking force based on the eddy current is generated in the braking drum 2. The eddy current is converted to heat and dissipated outside.

As shown in FIG. 7, a brake drum 2 made of a conductor such as iron has a heat radiation fin 2b integrally formed on an outer peripheral surface thereof, and has a right end formed by a number of spokes 9 extending radially outward from a mounting flange 10. Supported. In the conventional braking drum 2, since the heat radiation fin 2 b is cut from the thick braking drum 2, there is a problem that the selection of the material is restricted and the processing cost increases.

[0005] As disclosed in Japanese Patent Application Laid-Open No. 3-86062, in a brake drum which is divided into a main body portion in which eddy current is generated and a heat radiating portion for removing heat due to eddy current, the heat radiating portion is not provided. Since it is cast from aluminum or the like, it is difficult to reduce the thickness, and there is a problem in strength such as cracking when the thickness is reduced.

As mentioned above, one of the important functions of the braking drum 2 is to dissipate the heat generated during the braking action of the eddy current reduction device into the air. For this reason, a radiation fin 2b is provided on the outer peripheral surface to dissipate the heat of the braking drum 2 to the atmosphere. When the braking drum 2 is cooled by the radiating fins 2b, the shape of the radiating fins 2b is such that (a) the radiating efficiency is high. (B) The wind noise caused by the heat radiation fin 2b is not loud. (C) In order to prevent deterioration of fuel efficiency, the air resistance due to the heat radiation fin 2b is not large. …… 3
It is necessary to satisfy two design conditions.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an eddy current reduction device in which a braking drum satisfies the above three requirements and has a radiation fin which can be manufactured at low cost.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a construction of the present invention comprises a braking drum which rotates integrally with a rotating shaft, and a non-rotating portion of a vehicle which faces an inner peripheral surface of the braking drum. In the eddy current reduction device comprising the magnets arranged,
A band-shaped thin plate formed by cutting and raising a heat radiation fin at intervals in a longitudinal direction is joined to an outer peripheral surface of the braking drum.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a braking drum is divided into a main body portion in which eddy current is generated and a heat radiating portion for removing heat due to eddy current, and both are joined by brazing or the like. For the heat radiating part, use a band-shaped thin plate made of a material with excellent heat dissipation. And then fitted over the body.

[0010]

1 is a front sectional view of an eddy current reduction device according to the present invention. The brake drum 2 has its right end connected to, for example, the tip of a number of spokes 9 extending radially outward from a mounting flange 10 connected to the output shaft of the vehicle transmission. The guide cylinder 4 having an inner space 4c having a rectangular cross section is fixed to a non-rotating portion of the vehicle such that the outer cylinder 4a faces the inner peripheral surface 2a of the brake drum 2. A large number of ferromagnetic plates 5 are provided at equal intervals in the circumferential direction on an outer tube portion 4a of the guide tube 4, and a movable magnet support tube 17 is rotatably supported by a bearing 19 on an inner tube portion 4b. An immobile magnet support tube 16 is supported by a bearing 18 on a thin-walled cylindrical portion 17a extending from 17, and is fixed to the left end wall of the guide tube 4 by a bolt (not shown).

The arm 2 protruding leftward from the thin cylindrical portion 17a
Actuator 22 protrudes outside through slit 13a on the left end wall of guide tube 4 and is integral with guide tube 4.
a is connected to a rod 21a projecting from a. The actuator 22a is formed by inserting a piston 24a into a cylinder 23a, and a rod 21a connected to the piston 24a protrudes from the cylinder 23a to the outside.

According to the present invention, in order to reduce the processing cost of the heat radiation fin 2b for the braking drum 2 and to enhance the heat radiation performance, the radiation drum 3
A band-shaped thin plate having 2c is wound around or a heat radiation tube 32 formed from the band-shaped thin plate is fitted.

As shown in FIG. 2, the heat dissipating tube 32 is formed by cutting out three sides of a large number of rectangular plates at predetermined intervals in the longitudinal direction on a thin band-shaped thin plate 32a, and leaving the rectangular plates at the remaining one side. Bend at right angles. That is, the heat radiation fin 32c is formed by bending the piece cut and raised from the opening 32b perpendicularly to the plate surface. The heat dissipation tube 32 is formed by bending the thin plate 32a into a cylindrical shape. By using a material having a high thermal conductivity, such as copper, for example, for the thin plate 32 a, the heat of the braking drum 2 is
2, and heat exchange with the outside air is performed by the radiation fin 32c.

In the above embodiment, the stationary magnet support tube 16 and the movable magnet support tube 17 are disposed inside the guide tube 4, and the movable magnet support tube 17 is rotated forward and reverse to disengage from the braking position. Although the case of the eddy current reduction device of the type switching to the braking position has been described, the present invention is not limited to this,
As shown in FIG. 3, inside the guide cylinder 4, one magnet support cylinder 17 that couples the magnets 7 to the ferromagnetic plate 5 so that the polarities thereof are alternately different in the circumferential direction is rotatably supported. By rotating the cylinder 17 forward and backward, a braking position in which each magnet 7 entirely faces each ferromagnetic plate 5 and a non-braking position in which a pair of magnets 7 having different polarities partially face the common ferromagnetic plate 5. The present invention can also be applied to an eddy current reduction device of a type that switches to a braking position (the state shown).

Further, as shown in FIG. 4, one magnet support cylinder 17 that couples the magnet 7 to the ferromagnetic plate 5 in such a manner that the polarity of the magnet 7 is different by two in the circumferential direction is rotatable inside the guide cylinder 4. And the magnet support cylinder 17 is rotated forward and reverse so that the two magnets 7 facing the common ferromagnetic plate 5 have the same braking position (the state shown) and the magnet 7 facing the common ferromagnetic plate 5. The present invention is also applicable to an eddy current reduction device of a type in which the two magnets 7 are switched to a non-braking position in which the polarities of the two magnets 7 are different from each other.

As shown in FIG. 5, one magnet support cylinder 17 which is coupled inside the guide cylinder 4 so that the polarity of the magnet 7 with respect to the ferromagnetic plate 5 is alternately different in the circumferential direction can be moved in the axial direction. The magnet support cylinder 17 is protruded into the brake drum 2 so that each magnet 7 is completely opposed to each ferromagnetic plate 5 in a braking position (shown in the drawing). The present invention can also be applied to an eddy current reduction device of a type in which each magnet 7 is retired and switched to a non-braking position where each magnet 7 does not face each ferromagnetic plate 5.

Further, the present invention can be applied not only to the permanent magnet type eddy current reduction device but also to a braking drum of an electromagnet type eddy current reduction device.

[0018]

As described above, the present invention provides an eddy current comprising a braking drum which rotates integrally with a rotating shaft and a magnet which is disposed on a non-rotating portion of a vehicle so as to face the inner peripheral surface of the braking drum. In the reduction gear transmission, the belt-shaped thin plate formed by cutting and raising the heat radiation fins at intervals in the longitudinal direction is joined to the outer peripheral surface of the braking drum, and thus the following effects are obtained.

(A) Compared with the conventional example in which the heat radiation fin is cut into the brake drum, a brake drum excellent in heat radiation can be manufactured at low cost.

(B) Since the heat radiation fins are merely formed so as to be cut and raised from the strip-shaped thin plate, the shape of the heat radiation fins can be freely designed.

(C) A material different from the braking drum, for example, a material excellent in heat dissipation such as copper or aluminum, is used for the thin plate forming the heat radiation fin, and the braking drum is combined to form an eddy current reduction device. Performance can be greatly improved.

(D) Since the heat radiation fin can be press-formed, it is useful for weight reduction.

[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 perspective view showing a part of a thin plate on which a radiation fin is formed in a braking drum of the eddy current reduction device.

FIG. 3 is a side sectional view showing another type of eddy current reduction device to which the present invention is applied.

FIG. 4 is a side sectional view showing another type of eddy current reduction device to which the present invention is applied.

FIG. 5 is a front sectional view showing another type of eddy current reduction device to which the present invention is applied.

FIG. 6 is a perspective view of a braking drum of a conventional eddy current reduction device.

FIG. 7 is a perspective view of a braking drum of a conventional eddy current reduction device.

[Explanation of symbols]

2: brake drum 4: guide cylinder 4a: outer cylinder 4b: inner cylinder 4c: inner cavity 5: ferromagnetic plate 6, 7: magnet
9: Spoke 10: Mounting flange 13a: Slit 16, 17: Magnet support cylinder 17a: Thin cylindrical part 1
8, 19: bearing 20a: arm 21a: rod 22
a: Actuator 23a: Cylinder 24a: Piston 32: Heat radiating tube 32a: Thin plate 32b: Opening 3
2c: heat radiation fin

Claims (2)

[Claims] 1. An eddy current reduction device comprising a braking drum which rotates integrally with a rotating shaft and a magnet disposed on a non-rotating portion of a vehicle so as to face an inner peripheral surface of the braking drum. An eddy current reduction device characterized in that a strip-shaped thin plate cut and raised at intervals in the direction is joined to the outer peripheral surface of the braking drum. 2. The eddy current reduction device according to claim 1, wherein the heat radiation cylinder is formed by bending the strip-shaped thin plate, and the heat radiation cylinder is externally fitted to the braking drum.