JPH0574191U - Eddy current reducer rotor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a rotor for an eddy current type speed reducer, which is composed of a single material and has excellent magnetic characteristics and low electric resistance while maintaining high-temperature strength. A rotor ring 1 is fitted to one end of a rotary shaft 11, and a plurality of permanent magnets 8 are provided around the support ring 13 so that the polarities of adjacent magnets are opposite to each other. In the reduction gear transmission, in which the pole surface of the permanent magnet 8 is movable in the axial direction of the rotor 11 from the position where it is magnetically opposed to the rotor 1 to the position where it is completely separated in the required gap, the outer cylinder 2 of the rotor 1 is provided. Is an eddy current type speed reducer in which a decarburized layer 18 is provided on the inner peripheral surface of the. [Effect] The braking efficiency can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement in the rotor of an eddy current type speed reducer used in large vehicles such as buses and trucks.

[0002]

[Prior Art]

 As a deceleration device or braking device for large vehicles, in addition to the main brake, the foot brake, the auxiliary brake, the exhaust brake, stable deceleration when descending a long slope and preventing burnout of the foot brake Therefore, an eddy current type speed reducer is used. The eddy current type speed reducer includes one using an electromagnet and one using a permanent magnet.

In the former, an electromagnet having an electromagnetic coil wound around an iron core is used as a magnetic pole, and a large number of the magnetic poles are arranged on both sides of the disk. A magnetic field is generated by energization from a battery power source, and an eddy current phenomenon causes the disk. The torque is generated in the direction of decelerating the vehicle to obtain the braking force (Japanese Patent Laid-Open No. 615774/50). Since the eddy current type speed reducer uses an electromagnet having an electromagnetic coil wound around an iron core as a magnetic pole, it is heavy and has a large outer dimension, and therefore it is disadvantageous to be mounted on a vehicle with a limited space.

The latter was developed in order to eliminate the above-mentioned problems of the eddy current type speed reducer using the electromagnet, and a plurality of permanent magnets are provided by making the polarities of adjacent magnets opposite to each other. A support ring around which a magnet is provided is provided so that the magnetic pole surface of the permanent magnet can move back and forth in a required gap from a position where it is magnetically entirely opposed to the cylindrical portion of the rotor to a position where it is completely separated. An eddy current generated in a cylindrical portion of a rotor is turned on / off by a magnetic circuit of a permanent magnet (Japanese Patent Laid-Open No. 1-234043).

Since the eddy current type speed reducer is a device that obtains a braking force by passing an eddy current through the rotor, a material having excellent magnetic characteristics is used for the rotor. In addition, the resistance of the eddy current during braking causes the rotor to reach a temperature of 600 ° C or higher during high rotation and braking for a long time. Therefore, it is necessary to use a material having excellent high-temperature strength for the rotor.

[0006]

[Problems to be solved by the device]

 As described above, for the rotor of the eddy current type speed reducer, it is desirable to use a material having excellent magnetic properties and high temperature strength. However, magnetic properties and high temperature strength are in conflict with each other, and it is difficult for both of them to provide a single-layer rotor with excellent properties.

Further, in order to suppress Joule heat generation of eddy current, a two-layer structure rotor having a copper film having a low electric resistance on the inner surface of the rotor has been devised. However, there is a risk of deterioration and peeling of the coating due to repeated thermal fatigue due to on / off of the brake and difference in linear expansion coefficient.

In order to eliminate the above-mentioned drawbacks, the present invention provides a rotor for an eddy current type speed reducer, which is made of a single material and has high magnetic strength, excellent magnetic characteristics, and low electric resistance. ..

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the rotor of the eddy current type speed reducer of the present invention has a plurality of permanent magnets in which a rotor is fitted to one end of a rotary shaft so that the polarities of adjacent magnets are opposite to each other. The support ring that is installed around the rotor is provided in the axial direction of the rotary shaft so that the pole surface of the permanent magnet can move forwards and backwards from the position where it completely faces the rotor magnetically in the required air gap to the position where it completely separates from the rotor. In the eddy current type speed reducer, the rotor of the eddy current type speed reducer is provided with a decarburized layer on the inner peripheral surface of the rotor.

[0010]

[Action]

 A decarburized layer is formed on the inner peripheral surface of the rotor cylinder, and as the carbon content decreases, the electrical resistance decreases and the magnetic permeability increases, so while maintaining high-temperature strength, increasing the magnetic permeability and The electric resistance can be reduced. Therefore, the braking torque is improved by the improvement of the magnetic permeability and the suppression of the eddy current resistance heat generation due to the decrease of the electric resistance.

[0011]

【Example】

 An embodiment of this invention will be described with reference to FIGS. The mounting disk 6 of the rotor 1 is attached to the support member 16 fitted to one end of the rotary shaft 11 by a plurality of bolts 9. In this rotor 1, an outer cylinder 2 and an inner cylinder 3 are opposed to each other with a required space to form a cylindrical portion, and the outer cylinder 2 and the inner cylinder 3 are connected at their cylinder ends by a large number of arms 4 to form an outer cylinder 2 A large number of cooling fins 5 are circumferentially arranged at equal intervals on the outer peripheral surface of the inner cylinder 3, and a mounting disc 6 is provided on one end surface of the inner cylinder 3.

The cylindrical portion of the rotor 1 is generally made of S45C carbon steel or chrome-molybdenum steel in order to have the required strength, but in this invention, the outer cylinder 2 is decarburized to remove its inner surface. A coal bed 18 is provided. Next, an example of the decarburization treatment will be shown. Non-treated material: S45C carbon steel Treatment method: Hold in a temperature range of 600 to 900 ° C for 0.5 to 4 hours in wet hydrogen having a dew point of 40 to 70 ° C. Decarburization depth: 0.5-1.0 mm

In a space between the outer cylinder 2 and the inner cylinder 3, a support ring 13 having a width commensurate with the cylinder length is interposed. The support ring 13 is attached to a support plate 15 axially supported by the rotary shaft 11 via a bearing 14, and is supported by a plurality of guide rods (17) projecting in the axial direction of the rotary shaft 11 and supported. By moving the rod 7 that penetrates the ring 13 in the width direction forward and backward by the cylinder 10, the length from the position facing the rotor cylindrical portion to the magnetically offset position is provided so as to be forward and backward.

On the outer peripheral surface of the support ring 13, a plurality of permanent magnets 8 made of rare earth magnets are circumferentially arranged so that the magnetic poles of adjacent magnets are opposite to each other. The permanent magnet group is housed in the magnetic shield case 12 attached to the support plate 15 to prevent magnetic leakage. Further, a pole piece 19 is arranged in the magnetic shield case 12 so as to face the permanent magnet 8.

The speed reducer is used, for example, by attaching a mounting bracket (not shown) provided on the support plate 15 to the vehicle body and connecting the rotary shaft 11 to the propeller shaft.

When the support ring 13 is retracted and the permanent magnet group is magnetically separated from the cylindrical portion of the rotor 1, no eddy current flows in the rotor, so the rotor 1 rotates with a predetermined torque. The brake is off. When the cylinder 10 is started in this brake-off state, the rod 7 advances, the support ring 13 advances, and the pole pieces attached to the permanent magnet 8 with a predetermined gap on the inner surface of the outer cylinder 2 face each other. Then, a magnetic circuit is formed between the adjacent permanent magnets 8, the outer cylinder 2, and the support ring 13, and the so-called brake is turned on. At this time, the maximum braking torque is generated, and the vehicle is greatly decelerated.

As described above, the magnetic permeability of the inner peripheral surface of the outer cylinder 2 increases as the carbon content decreases due to the decarburization treatment, and the electric resistance decreases. Moreover, the high temperature strength of the outer cylinder as a whole can be maintained.

In the durability test, the eddy current type speed reducer shown in FIG. 1 to which the above rotor is attached is mounted on an actual truck, the rotor speed is fixed at 3800 rpm on a bench tester, and braking is turned on / off. The operation was repeated. At this time, changes in temperature of the center of the inner surface of the rotor (highest temperature site) and the center of the outer surface (cooling fin V-shaped apex root) were examined. The result is shown in FIG. From this figure, it can be seen that the maximum temperature at the center of the inner surface of the rotor is about 680 ° C and the minimum temperature is about 100 ° C.

In the eddy current type speed reducer shown in FIG. 1, an inner surface decarburizing drum provided with a decarburizing layer 18 on the outer cylinder 2 by the implementation of the present invention and an untreated drum which is not decarburized for comparison are used. A braking torque test was conducted. The result is shown in FIG. From this figure, it can be seen that the inner decarburizing drum according to the present invention has a better braking ability than the untreated drum, and an excellent braking torque can be obtained especially in a low rotational speed range.

[0020]

[Effect of the device]

 According to this invention, a decarburization layer is provided on the inner surface of the outer cylinder of the rotor cylindrical portion of the eddy current type speed reducer using a permanent magnet. It is possible to improve the braking efficiency.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a state of a decarburized layer by enlarging a part of an outer cylinder of a rotor according to an embodiment of the present invention.

FIG. 3 is a graph showing a comparison of braking characteristics between an eddy current type speed reducer having an internal decarburizing drum and an eddy current type speed reducer having an untreated drum according to an embodiment of the present invention.

[Explanation of symbols]

 1 Rotor 2 Outer Cylinder 3 Inner Cylinder 4 Arm 5 Cooling Fin 6 Mounting Disc 7 Rod 8 Permanent Magnet 9 Bolt 10 Cylinder 11 Rotating Shaft 12 Magnetic Shield Case 13 Support Ring 14 Bearing 15 Support Plate 16 Support Member 17 Guide Rod 18 Decarburization Layer 19 pole pieces

Claims (1)

[Scope of utility model registration request] 1. A rotor is fitted to one end of a rotary shaft,
A support ring, in which a plurality of permanent magnets are arranged so that the polarities of the adjacent magnets are opposite to each other, is magnetically entirely opposed to the rotor in the axial direction of the rotating shaft with the pole faces of the permanent magnets having a required gap. A rotor for an eddy current type speed reducer, characterized in that a decarburization layer is provided on the inner peripheral surface of the rotor in a speed reducer that can be freely moved back and forth from the position where it is fully removed.