JP2001078426A - Eddy current decelerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eddy current decelerator with high strength and a low cost outer cylinder part by a method, where the outer cylinder part is made of cast steel which is a ferromagnetic material, ferromagnetic parts of the outer cylinder corresponding to ferromagnetic plates are left as they are, and the nonmagnetic parts are austenitized by casting and diffusing nickel into those parts. SOLUTION: An eddy current decelerator comprises a brake drum 7 connected to a rotary shaft 1, a guide cylinder 10 which is placed in the brake drum, is attached to a nonrotary part such as a body, etc., has a hollow part 13 with a rectangular cross section and is made of a nonmagnetic material, a magnet support cylinder 14 which is housed in the hollow part 13 of the guide cylinder 10 to have at least its one side movable, a large number of magnets 24 arranged on the outer circumferential surface of the magnet support cylinder 14 in the circumferential direction at the same intervals and the outer cylinder part 10a of the guide cylinder 10, which has ferromagnetic parts 15 facing the respective magnets 24 and nonmagnetic parts which do not face the magnets 24. A braking force is generated in the brake drum 7 by eddy currents induced by magnetic fields from the magnets 24. The outer cylinder part 10a is made of cast steel, which is a ferromagnetic material, and the phase of the nonmagnetic parts are turned into an austenite phase by casting and diffusing nickel into those parts.

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 which is mainly mounted on a large vehicle and assists a friction brake. In particular, a magnetic member is provided on an outer cylinder portion of a guide cylinder interposed between a braking drum and a magnet support cylinder. The present invention relates to an eddy current reduction device in which a non-magnetic portion is formed by using a single metal and partially adding another metal.

[0002]

2. Description of the Related Art As disclosed in, for example, Japanese Patent Publication No. 6-81487, a guide cylinder having a rectangular hollow section is disposed inside a brake drum, and the brake drum is provided inside the guide cylinder. It accommodates a plurality of magnet support cylinders in which a large number of magnets whose polarities with respect to the inner peripheral surface are alternately changed in the circumferential direction are accommodated, and one magnet support cylinder is rotated forward / reverse by the arrangement pitch of the magnets, so that the outside of the guide cylinder is In an eddy current reduction device that switches between a braking position in which magnets of the same polarity arranged in the axial direction oppose the ferromagnetic plate in the cylindrical portion and a non-braking position in which magnets of different polarities face each other, the outer cylindrical portion is made of aluminum or the like. When casting from a non-magnetic material, a ferromagnetic plate made of low-carbon steel with high magnetic permeability such as SS400 is cast.

[0003] The outer cylinder part cast as described above has a weak joint between the ferromagnetic plate and the aluminum body, and is reinforced by filling an impregnating material or the like in the gap between the two. In addition, in order to finish the outer peripheral surface and the inner peripheral surface of the outer cylindrical portion to a smooth cylindrical surface after casting, there is a problem that a large cutting allowance has to be taken in order to remove the surface distortion, and the processing cost increases. .

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention comprises an outer cylinder made of cast steel which is a ferromagnetic material, leaving a ferromagnetic portion corresponding to a ferromagnetic plate as it is, and a non-magnetic portion being nickel. It is an object of the present invention to provide an eddy current reduction device provided with a strong and inexpensive outer cylinder portion formed by casting and melting austenite.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a brake drum connected to a rotating shaft and a cross-section inside the brake drum and attached to a non-rotating portion such as a vehicle body. A guide cylinder made of a non-magnetic material having a rectangular inner space, a magnet support cylinder at least one of which is accommodated in the inner space of the guide cylinder, and an outer circumferential surface of the magnet support cylinder at regular intervals in the circumferential direction; A plurality of magnets coupled to each other, and an outer cylinder portion of the guide cylinder having a ferromagnetic portion facing each of the magnets and a non-magnetic portion not facing the magnet, and an eddy current caused by a magnetic field from the magnets In the eddy current reduction device for generating a braking force based on the braking drum, the outer cylindrical portion is formed of a ferromagnetic cast steel, and the non-magnetic portion is cast and melted by nickel into a non-magnetic austenitic phase. It is characterized by having done.

Further, the structure of the present invention comprises a brake drum connected to a rotating shaft, and a non-magnetic material having a rectangular cross-section inside the brake drum and attached to a non-rotating portion such as a vehicle body. A guide tube, a magnet support tube housed in the inner space of the guide tube so as to be able to rotate forward and backward, and a circumferential direction such that the outer circumferential surface of the magnet support tube has two different polarities with respect to the inner circumferential surface of the braking drum. An outer cylinder portion of the guide cylinder having a large number of magnets coupled at equal intervals, a ferromagnetic portion facing the two magnets, and a non-magnetic portion not facing the magnet, and a magnetic field from the magnets In the eddy current reduction device for generating a braking force based on an eddy current on the braking drum, the outer cylinder portion is made of cast steel which is a ferromagnetic material, and the non-magnetic portion is made by casting and melting nickel. The austenitic phase of And butterflies.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, when an outer cylinder portion of a guide cylinder interposed between a braking drum and a magnet is cast from a ferromagnetic material or cast steel which is a magnetic material, it corresponds to a conventional ferromagnetic plate. The part is left as it is, and nickel is cast into the non-magnetic part to austenitize the structure. During the casting of the outer cylinder portion, the nickel melts into the cast steel to form austenite, and the non-magnetic portion is integrated with the nickel, so that the strength does not decrease, and the entire outer cylinder portion has a uniform strength. Also,
Machine processing of the inner and outer peripheral surfaces of the outer cylinder after casting requires a minimum processing allowance for smooth finishing.

[0008]

FIG. 1 is a front sectional view of an eddy current reduction device according to the present invention, and FIG. 2 is a side sectional view taken along line 2A-2A in FIG. The eddy current reduction device according to the present invention includes, for example, a braking drum 7 made of a conductor coupled to the output rotation shaft 1 of a vehicle transmission, and a guide cylinder 10 made of a non-magnetic material disposed inside the braking drum 7. , The inner space 13 of the guide tube 10 having a rectangular cross section
And a movable magnet support tube 14 and an immovable magnet support tube 14A housed in the housing. The brake drum 7 overlaps the flange 5a of the boss 5 together with the end wall of the brake drum 3 of the parking brake on the mounting flange 2 which is spline-fitted and fixed to the rotating shaft 1, and is fastened with a plurality of bolts 4 and nuts. You. The base end of a brake drum 7 provided with a cooling fin 7a is connected to a number of support arms 6 extending radially from the boss 5. Annular bodies 51 and 52 made of a good conductor such as copper are connected to both ends of the inner peripheral surface 7b of the braking drum 7 to increase the braking force by spreading the eddy current flow of the braking drum 7 in the axial direction.

The guide tube 10 has a left end wall 11a and an inner tube portion 10b.
The right end wall 11b made of an annular plate and the outer cylindrical portion 10a are connected to, for example, a cylindrical body having an L-shaped cross section integrally provided with the inner space portion 13 having a rectangular cross section. The guide tube 10 is fixed by a suitable means to a non-rotating part, for example, a gearbox of a vehicle transmission.

A movable magnet support tube 14 made of a magnetic material is supported by an inner tube portion 10b by a bearing 12 so that the movable magnet support tube 14 is rotatable in the forward and reverse directions. The arm 16 projecting from the magnet support tube 14 in the axial direction is connected to the left end wall 11 of the guide tube 10.
a through the slit 18a provided in the actuator 20a.
Is connected to the rod. The magnet support tube 14 is provided on the outer peripheral surface with the magnet 2 facing the left half of each ferromagnetic portion 15 of the outer tube portion 10a.
4 are coupled such that the polarity for the ferromagnetic portion 15 is circumferentially alternately different. The stationary magnet support tube 14A made of a magnetic material is attached to the inner space 13 of the guide tube 10 and the inner tube portion 10b.
And a magnet 24A facing the right half of each ferromagnetic portion 15 on the outer peripheral surface is coupled so that the polarity with respect to the ferromagnetic portion 15 is alternately different in the circumferential direction. The actuator 20 coupled to the left end wall 11a of the guide cylinder 10 is a cylinder 1
A piston 17 is fitted on the arm 8, and a rod projecting from the piston 17 to the outside is connected to the arm 16.

As shown in FIG. 2, the magnet 24A of the magnet support tube 14A has a cylindrical surface on the inner surface and the outer surface, and a non-magnetic material is inserted between step portions 35 formed at circumferential ends of the magnets 24A. A fixing bracket 31 made of a body and having a T-shaped cross section is engaged, and is fastened to the magnet support cylinder 14A by a bolt 32. Magnet 2
4 is similarly connected to the magnet support tube 14.

When the brake is not applied, as shown in FIG. 1, the magnet 24 of the magnet support tube 14 and the magnet 24A of the magnet support tube 14A are
The polarities facing the ferromagnetic portion 15 are opposite to each other. At this time, the magnets 24 and 24A form a short-circuit magnetic circuit w between each ferromagnetic portion 15 and the magnet support cylinders 14 and 14A, and do not apply a magnetic field to the braking drum 7. At the time of braking, when the magnet support cylinder 14 is rotated by the actuator 20 from the non-braking position to the braking position shown in FIG. 2 by an arrangement pitch of the magnets 24, the magnets 24, 24 A arranged in the axial direction become the ferromagnetic portions 1.
5 has the same polarity, and exerts a magnetic field on the braking drum 7 via the ferromagnetic portion 15. When the rotating brake drum 7 crosses the magnetic field, an eddy current flows through the brake drum 7, and the brake drum 7 generates a braking torque. At this time, each magnet 24,
24A forms a magnetic circuit z between the brake drum 7 and the magnet support cylinders 14 and 14A.

The present invention relates to a brake drum 7 and magnets 24, 24A.
The outer cylinder portion 10a of the guide cylinder 10 interposed between them is made of a ferromagnetic cast steel, and when the outer cylinder portion 10a is cast from the cast steel, nickel is cast into each of the non-magnetic portions 15a, thereby reducing the structure. It transforms into a non-magnetic austenitic phase. As shown in FIG. 2, the ferromagnetic portion 15 and the non-magnetic portion 15a of the outer cylindrical portion 10a are cast as a thick and uniform cylindrical body, and the inner and outer peripheral surfaces are cut into a smooth cylindrical surface.

As shown in FIG. 3, an axial groove 41 is integrally formed on the outer surface of the non-magnetic portion 15a so that the strength of the outer cylindrical portion 10a is not impaired, and the material amount of the non-magnetic portion 15a is reduced. You may reduce it. As shown in FIG. 4, instead of casting the molten nickel into the non-magnetic portion 15a when casting the outer cylindrical portion 10a, the nickel plate 42 is used instead of the non-magnetic portion 1 of the mold.
If the molten cast steel is poured into the mold and placed in advance in a portion corresponding to 5a, the nickel plate 42 melts into the cast steel, and the structure changes to a nonmagnetic austenite phase. The outer cylindrical portion 10a obtained as described above has a left end wall 11a and a right end wall 11b, preferably made of aluminum.
And connected by bolts. In FIGS. 2 and 3, the ferromagnetic portion 15 and the nonmagnetic portion 15a are sectioned by a straight line for convenience. Needless to say, there is a portion exhibiting the property of

[0015] As shown in Figs.
A single magnet support tube 14 is accommodated in the inner space 13 so as to be rotatable in the forward and reverse directions.
In addition, the present invention can be applied to an eddy current reduction device in which two magnets 24 facing each other are coupled so that the polarity with respect to the ferromagnetic portion 15 differs by two in the circumferential direction. The guide cylinder 10 is configured in the same manner as that shown in FIG. 1, in particular, the outer cylinder portion 10 a is made of cast steel, and nickel is cast and diffused in the non-magnetic portion 15 a thinned by the axial groove 41. The same applies to a nonmagnetic austenitic phase.

When two magnets 24 having different polarities face each ferromagnetic portion 15 during non-braking, a short-circuiting magnetic circuit w is formed between the ferromagnetic portion 15 and the magnet support cylinder 14, and the braking drum 7 Does not exert a magnetic field. At the time of braking, magnet support cylinder 1
4 is rotated by the pitch of the arrangement of the magnets 24, as shown in FIG.
At this time, a magnetic circuit z is formed between the braking drum 7 and the magnet support tube 14. When the rotating brake drum 7 crosses the magnetic field, a braking torque based on the eddy current is generated in the brake drum 7. Although the non-magnetic portion is made non-magnetic by diffusing nickel, substantially the same effect can be obtained even when the non-magnetic portion is not completely non-magnetized and is weakly magnetized.

[0017]

As described above, according to the present invention, a guide cylinder for accommodating a magnet support cylinder is disposed inside a braking drum connected to a rotating shaft, and a magnet of the magnet support cylinder is provided on an outer cylinder portion of the guide cylinder. In an eddy current reduction device having an opposed ferromagnetic portion and a non-magnetic portion not opposed to a magnet, the outer cylinder portion is made of a ferromagnetic cast steel, and the non-magnetic portion is cast and melted by nickel. Since the non-magnetic austenitic phase is used, the production is simple and the strength of the outer cylinder is significantly improved.

Since the outer cylinder is basically made of a single material, there is no distortion during casting, so that the machining of the inner and outer peripheral surfaces of the outer cylinder can be finished with a small cutting allowance. Manufacturing costs can be reduced.

[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 side sectional view of the eddy current reduction device.

FIG. 3 is an enlarged side sectional view showing an outer cylindrical portion according to a modified example of the present invention.

FIG. 4 is a side cross-sectional view of another type of outer cylinder portion according to a modified embodiment of the present invention.

FIG. 5 is a side sectional view showing a non-braking state of another type of eddy current reduction device to which the present invention is applied.

FIG. 6 is a side sectional view showing a braking state of the eddy current reduction device.

[Explanation of symbols]

1: rotating shaft 2: mounting flange 3: braking drum 6:
Support arm 7: braking drum 7a: cooling fin 7b: inner peripheral surface 10: guide cylinder 10
a: Outer tube part 10b: Inner tube part 11a: Left end wall 11
b: Right end wall 13: Interior space 14: Magnet support tube 14A: Magnet support tube 15: Ferromagnetic portion 15a: Non-magnetic portion 20: Actuator 24: Magnet 24A:
Magnet 31: Fixing bracket 41: Groove 42: Nickel plate

Claims (3)

[Claims] A brake drum connected to a rotating shaft, a guide cylinder made of a non-magnetic material having a rectangular cross-section hollow inside the brake drum and attached to a non-rotation part such as a vehicle body; At least one of the movable magnet support cylinders housed in the inner space of the guide cylinder, a large number of magnets coupled to the outer peripheral surface of the magnet support cylinder at equal intervals in the circumferential direction, and a ferromagnetic portion facing each of the magnets. An outer cylinder portion of the guide cylinder having a nonmagnetic portion that does not face the magnet, and an eddy current reduction device that generates a braking force based on an eddy current on the braking drum by a magnetic field from the magnet; An eddy current reduction device, wherein the outer cylinder portion is made of a ferromagnetic cast steel, and the non-magnetic portion is made of a non-magnetic austenitic phase by casting nickel. 2. A guide drum made of a non-magnetic material having a rectangular hollow section and mounted inside a non-rotating part such as a vehicle body inside the brake drum and connected to a rotating shaft. A magnet support cylinder housed in the inner space of the guide cylinder so as to be capable of rotating forward and backward, and an outer peripheral surface of the magnet support cylinder which is coupled to the outer peripheral surface of the brake drum at equal intervals in the circumferential direction such that the polarity with respect to the inner peripheral surface of the braking drum is different by two; A plurality of magnets, an outer tube portion of the guide tube having a ferromagnetic portion facing the two magnets and a non-magnetic portion not facing the magnets, based on an eddy current by a magnetic field from the magnets In the eddy current reduction device for generating a braking force on the braking drum, the outer cylinder portion is made of a ferromagnetic cast steel, and the non-magnetic portion is made of a non-magnetic austenitic phase by casting nickel. Eddy current reduction device. 3. The eddy current reduction device according to claim 1, wherein an axial groove is provided on an outer surface of said non-magnetic portion.