JP2000188858A - Eddy current reducer - Google Patents

Abstract

(57) [Problem] To provide an eddy current reduction device that is completely coupled to a ferromagnetic plate and has a small finishing amount by using a non-magnetic material instead of aluminum for an outer cylinder portion of a guide cylinder. . A braking drum (13) coupled to a rotating shaft (4),
An inner space 16 having a rectangular cross section inside the braking drum 13.
A stationary guide cylinder 18 made of a nonmagnetic material having at least one movable magnet support cylinder 1 inside the guide cylinder 18;
9, a plurality of magnets 20 connected to the outer circumferential surface of the magnet support tube 19 at equal intervals in the circumferential direction, and a ferromagnetic plate 21 cast in the outer tube portion 18a of the guide tube 18 at a position facing the magnet 20. And
The magnetic field reaching the braking drum 13 from the magnet 20 causes the braking drum 13 to generate a braking force based on the eddy current. The periphery of the ferromagnetic plate 21 of the guide cylinder 18 is made of austenitic ductile iron or austenitic cast steel.

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 using an austenitic ductile cast iron or an austenitic cast steel for an outer tube portion of a guide tube.

[0002]

2. Description of the Related Art In a conventional eddy current speed reducer, a ferromagnetic plate (pole piece) made of a soft magnetic material such as steel is cast using aluminum for an outer tube portion of a guide tube. Specifically, the ferromagnetic plate is heated to a temperature of 200 ° C. or more and cast into aluminum. Aluminum having a higher coefficient of thermal expansion has a higher temperature, a higher shrinkage ratio upon cooling, and a lower ferromagnetic plate In some cases, sink marks or voids may be formed between them, or a gap may be formed between the edge of the ferromagnetic plate and the aluminum, so that sufficient coupling may not be obtained. This tendency tends to occur in the inner and outer peripheral portions where cooling is fast. To avoid the above mentioned defects, 2
Although the sink is reduced by casting into a rough shape that is about twice as thick, the amount of machining and machining time of the inner and outer peripheral surfaces of the outer cylinder part of the guide cylinder are long, and the machinability is reduced due to intermittent turning of steel and aluminum. Well done.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the object of the present invention is to use a non-magnetic material instead of aluminum for the outer cylinder portion of the guide cylinder so that the coupling with the ferromagnetic plate is complete and the finish processing is completed. An object of the present invention is to provide an eddy current reduction device having a small volume.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a brake drum connected to a rotating shaft and a non-magnetic material having a rectangular cross section inside the brake drum. An at least one movable magnet support tube inside the guide tube, a large number of magnets connected to the outer peripheral surface of the magnet support tube at equal circumferential intervals, and An eddy current reduction device having a ferromagnetic plate cast in an outer cylinder portion of the guide cylinder at an opposing position, and generating a braking force based on an eddy current on the braking drum by a magnetic field reaching the braking drum from the magnet. Wherein the periphery of the ferromagnetic plate of the guide cylinder is made of austenitic ductile cast iron or austenitic cast steel.

The present invention also provides a stationary disk made of a non-magnetic material having a rectangular hollow section facing the braking disk, a braking disk coupled to the rotating shaft, and a stationary cylinder. At least one movable magnet support tube inside, a large number of magnets connected to the outer peripheral surface of the magnet support tube at equal intervals in the circumferential direction, and an outer cylinder portion of the guide tube at a position opposed to the magnet. An eddy current reduction device having a cast ferromagnetic plate and generating a braking force based on an eddy current in the braking drum by a magnetic field reaching the braking drum from the magnet; Is made of austenitic ductile iron or austenitic cast steel.

[0006]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a non-magnetic casting, for example, austenitic cast steel (SCH13) or austenitic ductile cast iron (ductile cast iron equivalent to FCDA-NiCr2O2) is used for the outer tube portion of the guide tube instead of aluminum. Then, a ferromagnetic plate made of steel, which is a soft magnetic material, is heated to about 700 ° C. (100 ° C. higher for austenitic cast steel) and cast. The coefficients of thermal expansion of the two are not so different from those of aluminum, and they are easily welded due to the high temperature.

[0007]

1 is a front sectional view of an eddy current reduction device to which the present invention is applied, and FIG. 2 is a side sectional view of the same. The eddy current reduction device couples the braking drum 13 to the rotating shaft 4. For this reason, the spline hole 5a is formed in the output rotary shaft 4 supported by the bearing 3 on the end wall of the gear box 2 of the transmission and protruding from the end wall.
The mounting flange 5 having the above is fitted and fastened by a nut 6 so as not to come off. The end wall of the brake drum 7 of the parking brake and the flange portion 9a integral with the boss 9 of the brake drum 13 of the eddy current reduction device are superimposed on the mounting flange 5 and fastened with a plurality of bolts 10 and nuts 10a. .

The braking drum 13 is made of a conductor such as iron or aluminum. Preferably, a copper cylinder 35 formed by molding a thin copper plate into a cylindrical shape on the inner peripheral surface 13c in order to improve the flow of eddy current. Be combined. The braking drum 13 has a base end formed with a number of spokes 12 extending radially from the boss 9.
Is combined with A large number of cooling fins 13a are integrally provided on the outer peripheral wall of the braking drum 13 at equal intervals in the circumferential direction.

A guide cylinder 18 having an inner space 16 having a rectangular cross section is coaxially arranged inside the braking drum 13. The stationary guide cylinder 18 is fixed by bolts 32 and 33 to a frame plate 31 externally fitted and fixed to the protruding wall 2 a of the gear box 2. Guide tube 1
The guide tube 8 may be formed by connecting an annular end wall plate to both ends of an outer tube portion 18a and an inner tube portion 18b, but the illustrated guide tube 18 has a U-shaped cross section of a left half made of ordinary iron or the like. And a right half portion made of a nonmagnetic material and having an inverted L-shaped cross section are connected by a number of bolts 14.

A large number of openings 21a (see FIG. 3) are provided at equal intervals in the circumferential direction in an outer cylinder portion 18a of the guide cylinder 18 facing the inner peripheral surface 13c of the braking drum 13, and each opening 21a has a ferromagnetic plate. 21 is fitted and fixed. In practice, the ferromagnetic plate 21
Is cast when the outer cylindrical portion 18a is cast.

A plurality of actuators (not shown) are supported on the frame plate 31 having the reinforcing ribs 31a at equal intervals in the circumferential direction. Referring to FIG. 6, actuator 34 has piston 36a fitted to cylinder 36 to define a pair of fluid pressure chambers, and is provided at the end of rod 17 projecting from piston 36a to inner space 16 of guide cylinder 18. The magnet support cylinder 19 is connected.
The magnet support tube 19 is supported by the inner space 16 of the guide tube 18 so as to be movable in the axial direction. Magnets 20 facing the respective ferromagnetic plates 21 are coupled to the outer peripheral surface of the magnet support cylinder 19 so that the polarities are alternately different in the circumferential direction.

At the time of braking, as shown in FIG. 1, the magnet supporting cylinder 19 is moved by the actuator rod 17 to the braking drum 13 as shown in FIG.
Of the magnet 2, the rotating braking drum 13
When crossing the magnetic field from 0 to the brake drum 13 via the ferromagnetic plate 21, an eddy current is generated in the brake drum 13 and the brake drum 13 generates a braking torque. The braking drum 13 generates heat due to the eddy current, and is cooled by the outside air directly or via the cooling fin 13a. At the time of braking, a magnetic circuit z is formed between the magnet support cylinder 19 and the braking drum 13 as shown in FIG. At the time of non-braking, if the magnet support cylinder 19 is moved leftward in FIG. 1 by the actuator and is withdrawn from the braking drum 13, the magnet 20 does not apply a magnetic field to the braking drum 13, and the braking drum 13 does not generate a braking torque. .

As shown in FIG. 3, according to the present invention, a ferromagnetic plate 2 made of steel having a predetermined shape and provided with a retaining projection 30 on the periphery.
1 is cast in advance. The ferromagnetic plate 21 is heated to a temperature of about 700 ° C. and arranged at equal intervals in the circumferential direction in a cylindrical mold, and is made of austenitic cast steel (SCH13) or austenitic ductile iron (FCDA-NiCr2O2).
The molten metal of considerable ductile cast iron) is poured into a mold to obtain an outer tube portion 18a of the guide tube 18 into which the ferromagnetic plate 21 is cast.
In order to suppress an increase in the weight of the guide tube 18, a portion of the outer tube portion 18a of the guide tube 18 that is in contact with the periphery of the ferromagnetic plate 21 is thickened, and the other portions are provided with grooves 21b on the outer peripheral surface, for example. The thickness of the outer cylindrical portion 18a is reduced. Outer tube part 1 of guide tube 18
The inner peripheral surface of 8a is a smooth cylindrical surface. Conversely, the outer cylinder 18
The outer peripheral surface of a may be a cylindrical surface, and a groove may be provided on the inner peripheral surface.

In the embodiment shown in FIG. 4, the ferromagnetic plate 21 is provided with axial grooves 21b and 21c on both the inner and outer surfaces except for the peripheral portion, so that the outer tube portion 18a of the guide tube 18 is made thinner. .

According to the present invention, the guide cylinder 18 and the ferromagnetic plate 2
Since the difference in the coefficient of thermal expansion from 1 is small, if the ferromagnetic plate 21 is preliminarily heated to 700 ° C. and placed inside the mold, and molten ductile cast iron is injected, a tight weld between the two can be obtained. The mechanical strength of the guide tube 18 is improved, and the increase in weight can be minimized by reducing the wall thickness.

In the above-described embodiment, the magnet support cylinder 19 is reciprocated in the axial direction with respect to the braking drum 13 so that the braking position where the magnet 20 faces the ferromagnetic plate 21 and the magnet 20 faces the ferromagnetic plate 21 Although the eddy current reduction device of the type that switches to the non-braking position is described, the present invention is not limited to this, and the magnet 20 opposed to each ferromagnetic plate 21 is provided on the outer peripheral surface of the magnet support cylinder 19. The magnets are rotated so that their polarities are alternately different in the circumferential direction, and the magnet support cylinder 19 is rotated in half the pitch of the magnets 20 in the forward and reverse directions. Two magnets 20 on plate 21
The present invention can also be applied to an eddy current reduction device of a type that switches to a non-braking position that is partially opposed.

Further, as shown in FIG.
Two magnets 20 oppose each ferromagnetic plate 21 and are coupled so that the polarities to the ferromagnetic plate 21 are different from each other by two in the circumferential direction. The magnet 2 of the same polarity is rotated forward and reverse to the ferromagnetic plate 21.
The present invention can also be applied to an eddy current reduction device of a type in which a braking position where 0 is opposed to a non-braking position where a magnet 20 of a different polarity faces the ferromagnetic plate 21.

As shown in FIG. 6, a guide cylinder 18 having a ferromagnetic plate 21 is provided inside the braking drum 13 and
An immovable magnet support tube 19A and a movable magnet support tube 19 are disposed in the inner space of the magnet 8, and the magnet support tube 19 supported on the inner tube portion 18b by the bearing 15 is rotated forward and reverse by the actuator 34, and the magnet The same polarity magnets 20 of the support cylinders 19 and 19A,
A braking position in which the magnet 20A is entirely opposed to the common ferromagnetic plate 21, and magnets 20 and 2 having different polarities in the magnet support cylinders 19 and 19A.
The present invention can also be applied to an eddy current reduction device of a type in which 0A is switched to a non-braking position where the common ferromagnetic plate 21 entirely faces the common ferromagnetic plate 21.

In the embodiment shown in FIGS. 7 and 8, the eddy current reduction device comprises a conductor connected to the rotating shaft 4 and has a ventilation passage 53.
a pair of brake discs 53 having a, a stationary guide cylinder 58 made of a non-magnetic material disposed between the brake discs 53, and a forward and reverse rotation supported by the inner space of the guide cylinder 58. And a magnet support ring or magnet support cylinder 59. The guide cylinder 58 is formed integrally with a spoke 55 extending radially from the boss 56, and the boss 56 is supported on the rotating shaft 4 by a bearing 57.
The guide tube 58 is fixed by a suitable means to, for example, a gearbox of a transmission. A large number of ferromagnetic plates 6 are provided on both end walls of the guide cylinder 58.
1 are connected at equal intervals in the circumferential direction. The magnet support cylinder 59 is rotatably supported from outside by a bearing 54 in the inner space of the guide cylinder 58. A large number of magnets 60 are arranged in the magnet support cylinder 59 at equal intervals in the circumferential direction. Two magnets 60 are opposed to each ferromagnetic plate 61. A thin sliding plate 41 a impregnated with lubricating oil is connected to both side surfaces of the magnet support cylinder 59, and is brought into sliding contact with the ferromagnetic plate 61.

As shown in FIG. 8, a large number of fan-shaped magnets 60 are mounted on the magnet support cylinder 59 so that each of the ferromagnetic plates 6 having an area approximately twice as large.
The ferromagnetic plates 61 are arranged so that the polarities of the ferromagnetic plates 61 are different from each other by two in the circumferential direction. Magnet support cylinder 5
The small gear of the electric motor fixed to the guide cylinder 58 meshes with the partial gear formed on the outer cylinder 51 of the ninth, and the magnet support cylinder 59 can be rotated forward and backward by the pitch of the magnets 60 arranged.

When no braking is performed, two magnets 6 adjacent in the circumferential direction
In an arrangement in which the polarities of the zero ferromagnetic plate 61 are different from each other, a short-circuit magnetic circuit is generated between the pair of left and right ferromagnetic plates 61, and no magnetic field is applied to the braking disk 53. Since the pair of left and right ferromagnetic plates 61 sandwich the two magnets 60 from both sides, almost no magnetic flux leaks to the braking disk 53. When the magnet support cylinder 59 is rotated by the pitch of the arrangement of the magnets 60 during braking, the two magnets 60 have the same polarity with respect to the ferromagnetic plate 61. Thus, the two magnets 60 equally exert a magnetic field on the braking disk 53 via the ferromagnetic plate 61. When the rotating brake disk 53 crosses the magnetic field, an eddy current is generated in the brake disk 53 and the brake disk 53 receives a braking torque.
At this time, a magnetic circuit z is generated between the pair of braking disks 53.

In the above-described eddy current reduction gear, the guide cylinder 58 is divided into a C-shaped main body and a cover plate 58a, and is provided on the end wall of the guide cylinder 58 made of austenitic ductile cast iron or austenitic cast steel in the circumferential direction. A large number of ferromagnetic plates 61 are cast at intervals. In this case, the end wall of the guide cylinder 58 is formed to be thin by providing a radial groove at a portion between the ferromagnetic plates 61. Similarly, the lid plate 58a is formed to be thin by providing a radial groove in a portion between the ferromagnetic plates 61.

The present invention relates to the embodiment shown in FIGS.
Instead of the two magnets 60, a magnet having the same size as the ferromagnetic plate 61 is coupled to the magnet support tube 59 so that the polarity with respect to the ferromagnetic plate 61 is alternately different in the circumferential direction. An eddy current of a type in which the magnet is rotated forward and backward by the arrangement pitch to switch between a braking position in which the magnet entirely faces the ferromagnetic plate 61 and a non-braking position in which two magnets partially face the ferromagnetic plate 61. It can also be applied to reduction gears.

As shown in FIGS. 9 and 10, the present invention can also be applied to an eddy current reduction device that supports two inner and outer magnet support cylinders 59 and 59A inside a guide cylinder 58. The eddy current reduction device is composed of a braking disk 53 made of a conductor coupled to the output rotation shaft 4 of the vehicle transmission by a spline 71 and a pair of guides made of a non-magnetic material disposed on both sides of the braking disk 53. Cylinder 58
And a pair of inner and outer magnet support cylinders 59 and 59A supported in the inner space of the guide cylinder 58. The braking disk 53 is fixed to the rotating shaft 4 by a spline 71. Each guide tube 58 has an inner space portion having a rectangular cross section, and the boss is connected to the bearing 6.
It is supported on a rotating shaft 4 by 3 and fixed by suitable means, for example, to a gearbox of a transmission. Bearing 63 is nut 6
2, the movement in the axial direction can be suppressed. A large number of recesses are provided at equal circumferential intervals on the wall surface of the guide cylinder 58 made of austenitic ductile iron or austenitic cast steel facing the braking disk 53, and each recess has a substantially rectangular or sector-shaped ferromagnetic plate made of steel. (Pole piece) 61 is fitted and fixed. The ferromagnetic plate 61 is cast when the guide cylinder 58 is formed. A pair of inner and outer magnet support cylinders 59 and 59A made of a magnetic material supporting a large number of magnets 60 and 60A
8 so as to be relatively rotatable. In the illustrated embodiment, the magnet support cylinder 59 is fixed to the guide cylinder 58, and the magnet support cylinder 59A is supported so as to be able to rotate forward and backward.

The magnet support cylinders 59, 59A made of a magnetic material connect a large number of magnets 60, 60A, respectively. More specifically, the magnets 60 and 60A are arranged so as to face the ferromagnetic plates 61 one by one, and to have the polarities to the ferromagnetic plates 61 alternately different in the circumferential direction. The magnets 60 and 60A are magnet support cylinders 5
It is cast into 9,59A. A small gear (not shown) of an electric motor fixed to the guide cylinder 58 meshes with a partial gear 64 formed on the outer peripheral wall of the magnet support cylinder 59A.
A can be rotated forward and backward by the arrangement pitch of the magnet 60A.

When the brake is not applied, the inner and outer 2
The polarities of the two magnets 60, 60A are opposite to each other.
The magnets 60 and 60A are composed of the ferromagnetic plate 61 and the magnet support cylinders 59 and 5,
A short-circuit magnetic circuit w indicated by a chain line is formed between 9A and no magnetic field is applied to the braking disk 53. At the time of braking, the magnet support cylinder 59
When A is rotated by an arrangement pitch of the magnets 60A by an electric motor, the polarities of the two sets of magnets 60, 60A for each ferromagnetic plate 61 become the same, and as shown in FIG. 10, each magnet 60, 60A (shown in FIG. 10). Zu) is a pair of left and right magnet support cylinders 5
A magnetic circuit z is formed between 9, 59A (not shown), and when the rotating braking disk 53 crosses the magnetic field, an eddy current is generated in the braking disk 53, and the braking disk 53 receives a braking torque. .

[0027]

As described above, the present invention provides a brake drum or a brake disk connected to a rotating shaft, and a non-conductive portion having a rectangular cross section inside the brake drum or opposed to the brake disk. An immovable guide tube made of a magnetic material, at least one movable magnet support tube inside the guide tube, a large number of magnets connected to the outer peripheral surface of the magnet support tube at equal intervals in the circumferential direction; An eddy current that has a ferromagnetic plate cast in an outer cylindrical portion of the guide cylinder at a position facing the magnet, and that generates a braking force based on an eddy current in the braking drum by a magnetic field reaching the braking drum from the magnet; In the reduction gear transmission, since the periphery of the ferromagnetic plate of the guide cylinder is made of austenitic ductile cast iron or austenitic cast steel, the guide cylinder becomes slightly heavier, but the difference in the coefficient of thermal expansion between the guide cylinder and the ferromagnetic plate is reduced. The distortion is so small Fence, high bonding strength can be obtained, and since the finishing amount after casting it less, can reduce manufacturing costs.

Even if the thickness of the outer cylinder portion of the guide cylinder is made thinner than the ferromagnetic plate, there is no problem in the strength, and an increase in the weight of the guide cylinder can be minimized.

[Brief description of the drawings]

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

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

FIG. 3 is a side sectional view of a guide cylinder in which a ferromagnetic plate of the eddy current reduction device is cast.

FIG. 4 is a side sectional view of another guide cylinder in which a ferromagnetic plate of the eddy current reduction device is cast.

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

FIG. 6 is a front sectional view of another type of eddy current reduction device to which the present invention is applied.

FIG. 7 is a front sectional view of another type of eddy current reduction device to which the present invention is applied.

FIG. 8 is a developed plan sectional view of the eddy current reduction device.

FIG. 9 is a front sectional view of another type of eddy current reduction device to which the present invention is applied.

FIG. 10 is a developed sectional view of the eddy current reduction device.

[Explanation of symbols]

4: rotating shaft 12: spoke 13: braking drum 1
8: guide cylinder 18a: outer cylinder 18b: inner cylinder 19,
19A: Magnet support cylinder 20, 20A: Magnet 21: Ferromagnetic plate 21b, 21c: Groove 30: Retaining ridge 34:
Actuator 50: Spoke 51: Outer cylinder 52:
Inner cylinder 53: braking disk 55: spoke 58: guide cylinder 58a: lid plate 59, 59A: magnet support cylinder 60, 6
0A: Magnet 61: Ferromagnetic plate

Claims (2)

[Claims] 1. A stationary drum connected to a rotating shaft, a stationary guide cylinder made of a non-magnetic material having an inner space with a rectangular cross section inside the brake drum, and at least a small amount inside the guide cylinder. A movable magnet support cylinder, a number of magnets coupled to the outer peripheral surface of the magnet support cylinder at equal intervals in the circumferential direction, and a ferromagnetic cast in the outer cylinder portion of the guide cylinder at a position opposed to the magnet. An eddy current reduction device for generating a braking force based on an eddy current in the braking drum by a magnetic field reaching the braking drum from the magnet, wherein the periphery of the ferromagnetic plate of the guide cylinder is austenitic ductile cast iron. An eddy current reduction device characterized by comprising austenitic cast steel. 2. An immovable guide tube made of a non-magnetic material having a rectangular hollow section facing the brake disk and a brake disk connected to the rotating shaft, and a small number of internal guide tubes. Tomo 1
Two movable magnet support cylinders, a large number of magnets connected to the outer peripheral surface of the magnet support cylinder at equal circumferential intervals, and a ferromagnetic plate cast in the outer cylinder portion of the guide cylinder at a position opposite to the magnet. Has,
In an eddy current reduction device that generates a braking force based on an eddy current in the braking drum by a magnetic field reaching the braking drum from the magnet, the periphery of the ferromagnetic plate of the guide cylinder is formed of austenitic ductile cast iron or austenitic cast steel. An eddy current reduction device characterized by the following.