JP2701390B2 - Eddy current type reduction gear - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an eddy current type reduction gear used for a large vehicle such as a bus or a truck.

2. Description of the Related Art In addition to the foot brake as the main brake and the exhaust brake as the auxiliary brake, the deceleration or braking device for heavy-duty vehicles performs stable deceleration when descending on a long hill, etc. To prevent this, an eddy current type speed reducer is used.

This eddy current type speed reducer has an electromagnet in which an electromagnetic coil is wound around an iron core as a magnetic pole, and a large number of the magnetic poles are arranged on both sides of the disk. A torque is generated in the direction of decelerating the disk to obtain a braking force (Japanese Patent Application Laid-Open No.
50-61574).

Since the above-mentioned eddy current type reduction gear uses an electromagnet in which an electromagnetic coil is wound around an iron core as a magnetic pole, the weight is heavy,
Moreover, since the external dimensions are large, it is disadvantageous to mount the vehicle in a limited space. When the brake is ON, it is necessary to continuously supply power, and the power consumption of the battery is severe, so that it is necessary to increase the battery capacity and the power generation function.

In order to eliminate such a problem, the applicant has developed an eddy current type speed reducer using a permanent magnet (JP-A-63-1276).
No. 95).

In this eddy current type speed reducer, a pair of rotors whose disk surfaces are opposed to each other at a distance are fitted to a rotating shaft, and a plurality of fan-shaped ferromagnetic switch plates opposed to each other with an air gap on the disk surface are provided. A pair of switch plate supporting frames made of a magnetic material and supported by the rotating shaft are installed at a distance apart from each other, and the individual switch plates are circumferentially arranged magnetically insulated from each other. A plurality of permanent magnets of the same shape as the switch plate are circumferentially arranged in a donut-shaped non-magnetic permanent magnet support frame pivotally supported by the switch plate support frame between the plate groups with opposite polarities to switch both magnetic pole surfaces. The switch plate support frame and the permanent magnet support frame are provided so as to be rotatable relative to each other by a predetermined angle.

Problems to be Solved by the Invention The eddy current type speed reducer using permanent magnets described above was able to solve the problems of the conventional electromagnet type speed reducer.

However, when the switch is turned off, a magnetic circuit is formed by the switch plates on both sides and the adjacent permanent magnets without generating an eddy current in the disk. For this purpose, it is necessary to make the switch plate sufficiently thick so that magnetic flux does not flow to the disk side.

SUMMARY OF THE INVENTION An object of the present invention is to provide an eddy current type speed reducer in which the above points are changed and a thin switch plate is used.

Means for Solving the Problems In order to achieve the above object, an eddy current type speed reducer according to the present invention is characterized in that a pair of rotors whose disk surfaces are opposed to each other at a distance are fitted to a rotating shaft, and a gap is formed in the disk surface. A pair of switch plate groups each composed of a plurality of thin fan-shaped ferromagnetic switch plates opposed to each other are assembled into a pair of switch plate support frames made of a non-magnetic material and supported by the rotation shaft. And at least two sets of donut-shaped non-magnetic members supported on the switch plate support frame between the two side switch plate groups. A plurality of permanent magnets of the same shape as the switch plate are circumferentially arranged on the permanent magnet support frame with opposite polarities, so that the inner magnetic pole faces face different poles when braking is ON, and face the same poles when braking OFF. And the outer pole face is Respectively to face the switch plate group, formed by providing a switch plate support frame and the permanent magnet support frame freely relatively rotated by a predetermined angle.

It is desirable that there is no gap between the switch plate and the magnetic pole surface of each permanent magnet in terms of the magnetic circuit configuration. However, if the contact is strong, the rotation becomes difficult. In addition, a thin plate of a ferromagnetic oilless metal can be adhered to the magnetic pole surface to eliminate a gap with the switch plate and to ensure smooth rotation.

According to the above configuration, in the braking ON state where the permanent magnets and the switch plate overlap each other, the magnetic circuit including the adjacent switch plates on both sides and the disk surface of the rotor is provided between the adjacent permanent magnets as shown in FIG. Is formed, and an eddy current phenomenon occurs, whereby a braking torque is generated, and the speed is reduced according to the braking torque. In the braking OFF state in which one of the permanent magnet support frame and the switch plate support frame is rotated from the overlapping position, the permanent magnets straddle the adjacent switch plate as shown in FIG. If it is set to be in a state of being overlapped by half, a magnetic circuit is formed between adjacent permanent magnets, including one switch plate on each side,
Since no magnetic flux generated from the permanent magnet acts on the disk surface, no eddy current flows and no braking torque is generated. At the time of braking OFF, the magnetic flux repelled by the S pole and the S pole or the same pole surface of the N pole and the N pole being overlapped, and the magnetic flux flowing through the switch plate is weakened. Therefore, even if the switch plate is thinned, the magnetic flux does not leak to the rotor. When the switch plate is formed to be thin in this way, a decrease in magnetic flux at the switch plate when braking is ON is reduced, and braking can be performed efficiently.

Embodiment An embodiment of the present invention will be described with reference to FIG. 1 and FIG.

A switch plate support frame (2) is pivotally supported at the center of the rotating shaft (1) via a bearing (8), and a relatively thin fan-shaped ferromagnetic material is provided on the outer periphery of the switch plate support frame (2). A plurality of switch plates (3-1) and (3-2) are paired at a distance from each other, and each switch plate (3-1) (3-2) is a second switch plate. As shown in FIG. C, magnetically insulated and arranged circumferentially with a frame member (2-1) interposed. The switch plate can be integrally formed with a support frame made of aluminum, for example, by casting.

A plurality (three in the figure) of permanent magnet supporting frames (6 shown in the figure) rotatably supported by the switch plate supporting frame (2) via bearings (12) between the left and right switch plate groups.
-1) (6-2) and (6-3) are provided in an overlapping manner, and the switch plate (3-1) (3-
Inner permanent magnet (4) and outer permanent magnet (5-
1) A plurality of (5-2) are insulated from each other by frame members (4-1) and (6-3) and circumferentially arranged (portions A and B in FIG. 2). As the permanent magnets (4), (5-1) and (5-2), it is desirable to use rare earth magnets having excellent magnetic properties, such as rare earth cobalt magnets and rare earth / iron / boron magnets.

The cylinder (9) is attached to the switch plate support frame (2), and the spherical tip (10) formed on the piston rod is attached to the permanent magnet support frame (6-1) (6-2) (6-3). The cylinder (9) is actuated to allow a set of permanent magnets (4) (5-1) to be loosely fitted to the joined and protruded seats (11).
(5-2) is adjacent to two switch plates (3-1) (3
-2) It is provided so as to be able to rotate so as to overlap both by half. In addition, although the case where two cylinders are provided is shown in the drawings, the rotation can be similarly performed by one cylinder.

Instead of the rotating mechanism using the cylinder, a rack is attached to the peripheral surface of the permanent magnet support frame, and a pinion that meshes with the rack is pivotally supported on the switch plate support frame, and the rotation of the pinion causes the permanent magnet support frame to rotate. It can also be provided rotatably. A small gap is provided between the magnetic pole surfaces of the outer permanent magnets (5-1) and (5-2) and the switch plate (3) as long as rotation between them is not hindered. An oilless metal thin plate made of a material such as, can be attached to the outer magnetic pole surface of the permanent magnet.

Then, a pair of rotors (7-1) and (7-2) are fitted to the rotating shaft (1) with the disk surfaces facing the outer surfaces of the switch plate groups on both sides.

In the eddy current type speed reducer configured as described above, the mounting seat (13) protruding from the switch plate support frame (2) is attached to the vehicle body, and both ends of the rotating shaft (1) are connected to the propeller via the cross joint. Connect in the middle of the shaft.

A pair of outer permanent magnets (5-1), inner permanent magnets (4), and outer permanent magnets (5-2) are halved across two adjacent switch plates (3-1) and (3-2). In the overlapping state, as shown in FIG. 4, two sets of adjacent permanent magnets and one switch plate (3-1) (3
-2) constitutes a magnetic circuit, and the rotors (7-1) (7)
Since the magnetic flux generated from the permanent magnet does not act on the disk surface of -2), no eddy current is generated on the disk surface. Therefore, in this state, the reduction gear transmission is in the OFF state.

While the vehicle is running with the speed reduction device turned off as described above, the cylinder (9) of the rotating mechanism is operated by remote control from the driver's cab, and as shown in FIG. If (3-1) and (3-2) overlap, two adjacent permanent magnet groups and the adjacent switch plates (3-1) (3-1) and (3-2) (3--2) 2) and the disk surfaces of the rotors (6-1) and (6-2) form a magnetic circuit, and the outer permanent magnets (5-1) (5)
Since the magnetic flux from -2) acts to generate an eddy current, a braking torque corresponding to the eddy current is generated, and the vehicle is decelerated. Therefore, in this state, the reduction gear transmission is in the ON state.

The above is a case where the permanent magnet is constituted by a group of three permanent magnets in which the outer permanent magnets are superimposed on both magnetic pole surfaces of the inner permanent magnets. However, a combination of two or more magnets has the same operation and effect.

Effect of the Invention The present invention has the above-described structure, and generates a braking force on a rotor by a simple operation of slightly turning either the permanent magnet support frame or the switch plate support frame to change the overlapping state of the permanent magnet and the switch plate. Can be controlled. Further, power is not consumed during braking, which is economically advantageous.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a reduction gear transmission according to the present invention, and FIG. 2 is a side view of FIG. 1 which is divided into A, B, C and D parts, and A, B, C and D in FIG.
FIG. 3 is a side view or a cross-sectional view on each line. FIG. 3 is an explanatory view showing the magnetic circuit configuration of the permanent magnet in the braking ON state.
The figure is an explanatory view showing the magnetic circuit configuration of the permanent magnet in the braking OFF state. DESCRIPTION OF SYMBOLS 1 ... Rotating shaft 2 ... Switch board support frame 2-1 ... Frame member 3-1 and 3-2 ... Switch board 4 ... Inner permanent magnet 5-1 and 5-2 ... Outer permanent magnet 6 1,6-2,6-3 ... Permanent magnet support frame 6-4 ... Frame member 7-1,7-2 ... Rotor 8,12 ... Bearing 9 ... Cylinder 10 ... Spherical tip 11 ... Receiving seat 13: Mounting seat

Claims (1)

(57) [Claims] A pair of rotors, each having a disk surface opposed to each other at a distance, are fitted to a rotating shaft, and are formed of a plurality of thin fan-shaped ferromagnetic switch plates opposed to each other with a gap in the disk surface. A pair of switch plate groups are provided with a built-in distance from a pair of switch plate support frames made of a non-magnetic material and supported by the rotation shaft, and the individual switch plates are magnetically insulated from each other. A plurality of permanent magnets of the same shape as the switch plate are circularly arranged on two or more pairs of permanent magnet support frames of donut-shaped non-magnetic material which are circumferentially disposed and are supported by the switch plate support frame between the switch plate groups on both sides. The inner magnetic pole faces are configured so that different poles face each other when braking is ON, and the same poles face each other when braking is OFF.The outer magnetic pole faces face the switch plate group, respectively, and Match each permanent magnet support frame Eddy current retarder device provided freely rotated by a predetermined angle in manner.