JPH04344164A - Eddy-current type retarder - Google Patents

Abstract

PURPOSE:To stably assemble movable components without receiving any influence from the magnetic force of permanent magnets and, in addition, to reduce the overall dimension of an eddy-current type retarder in the axial direction. CONSTITUTION:A magnet supporting body 20 is provided between a brake drum 13 and a circuit switching member 37. A large number of V-shaped magnetic pole members 31 are arranged on the supporting body 20 at regular intervals in the peripheral direction so that the base ends of the members 31 can be respectively faced to the drum 13 and permanent magnets 32 are coupled with one side of the forked front ends of the members 31 so that the polarity of the magnets 32 can be alternately changed in the peripheral direction. Then U-shaped ferromagnetic members 35 both ends of which are faced to the forked front ends of the members 31 are arranged on a circuit switching member 37 at regular intervals in the peripheral direction. In addition, a rotationally driving means 50 which rotates the member 37 is provided at a non-braking position where both ends of the ferromagnetic members 35 of the member 37 are faced to the forked front ends of the magnetic pole members 31 and a braking position where both ends of the members 35 are faced to the spaces between each adjacent front ends of the members 31.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current speed reduction device that mainly assists the friction brake of large vehicles, and more particularly to an eddy current speed reduction device that can shorten the axial dimension.

0002

[Prior Art] The eddy current reduction gear according to Japanese Patent Application Laid-open No. 1-234043 has a fixed frame that projects into the inside of a brake drum.
A magnet support ring that connects a large number of permanent magnets at equal intervals in the circumferential direction is supported movably in the axial direction by an actuator,
The magnet support ring protrudes into the inside of the brake drum in a braking position where the permanent magnet applies a magnetic field to the inner circumferential surface of the brake drum, and in a non-braking position where it is retired from the brake drum and the permanent magnet does not apply a magnetic field to the inner circumferential surface of the brake drum. The position can be switched.

The above-mentioned eddy current type reduction gear has a long fixed frame in the axial direction, so the reduction gear can be installed together with the parking brake in a narrow installation space, for example, at the connection between the output rotating shaft and the propulsion shaft of the transmission under the floor of the vehicle body. There are various difficulties in arranging it. Further, in order to increase the braking capacity, for example, if the circumferential dimension of the permanent magnets is increased without changing the inner diameter of the brake drum, the amount of magnetic leakage due to the proximity of the permanent magnets to each other increases. Therefore, if the axial dimension of the permanent magnet is lengthened, not only the fixed frame but also the actuator that drives the magnet support ring will need to have a long stroke, so many components will have to be changed, and this will reduce weight and cost. Undesirable. Further, when assembling the device, the permanent magnet of the magnet support ring exerts a magnetic force on the component members, which is disadvantageous in that the assembly work is hindered.

0004

[Problems to be Solved by the Invention] An object of the present invention is to provide an eddy current reduction gear in which movable components are stably assembled without being affected by the magnetic force of permanent magnets, and in which the overall axial dimension can be shortened. There is a particular thing.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention has a structure in which a magnet support is disposed between the braking rotor and the circuit switching member, and the magnet support is arranged at equal intervals in the circumferential direction. A large number of V-shaped magnetic pole materials are arranged in parallel so that their base ends face the brake rotor, and permanent magnets are coupled to one leg of the bifurcated tip of the magnetic pole materials so that the polarity alternately differs in the circumferential direction. U-shaped ferromagnetic materials with both ends facing the bifurcated tip of each magnetic pole material are arranged side by side at equal intervals in the circumferential direction on the circuit switching member, and both ends of each ferromagnetic material of the circuit switching member are arranged in the bifurcated shape of each magnetic pole material. A rotation drive means for causing relative rotation between the magnet support and the circuit switching member is provided in a non-braking position facing the tips of the magnetic poles and in a braking position facing the tips of the adjacent magnetic pole materials.

[0006]

[Operation] A large number of V-shaped magnetic poles are integrally formed with a permanent magnet between the rotating brake body and a circuit switching member that connects a large number of U-shaped ferromagnetic members facing the rotating brake body at equal intervals in the circumferential direction. A magnet support that connects the members at equal intervals in the circumferential direction is coaxially arranged, and the circuit switching member can be rotated by a half pitch with respect to the magnet support. In the non-braking position where the bifurcated tip of each magnetic pole material of the magnet support faces both ends of each ferromagnetic material of the circuit switching member, a short circuit occurs between the V-shaped magnetic pole material containing the permanent magnet and the U-shaped ferromagnetic material. Since a magnetic circuit is created and no magnetic field is exerted on the rotary brake body, the rotary brake body is not subjected to any braking force.

When the circuit switching member is rotated by a half pitch with respect to the magnet support, the ferromagnetic material straddles the bifurcated tips of the adjacent magnetic pole materials. A magnetic circuit that straddles the rotary brake body is created between the base ends of adjacent magnetic pole materials. When the rotary brake body crosses the magnetic field from the magnetic pole material, eddy currents flow through the rotary brake body, and the rotary brake body receives a braking force.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side sectional view showing an embodiment in which an eddy current speed reduction device according to the present invention is disposed at the rear end of a vehicle transmission. A mounting flange 7 is spline-fitted to an output rotating shaft 4 supported by a bearing 3 on the rear end wall of the transmission 2 and fastened with a nut 5 . An end wall of a brake drum 16 of a known parking brake and an end wall 10 of a brake drum 13 of a speed reduction device are superimposed on the mounting flange 7 and fastened with a plurality of bolts 8 and nuts 9. The brake drum 13 constitutes a rotary brake body of the reduction gear according to the invention. A yoke 6, which is a universal joint for connecting the rotating shaft 4 and a known propulsion shaft, is fitted into a mounting flange 7 and connected with bolts (not shown). The brake drum 13 is provided with a large number of cooling fins 12 at equal intervals in the circumferential direction on its outer peripheral wall.

The inner peripheral surface of the brake drum 13 and the brake drum 16
A cylindrical fixed frame 17 made of a non-magnetic material is disposed in the space between the outer circumferential surface and the outer circumferential surface. Therefore, a circular frame plate 15 having reinforcing ribs 15a is fixed to the rear end wall of the transmission 2 via the mounting plate 14, and a fixed frame 17 is fixed to the frame plate 15. The fixed frame 17 is constructed by connecting an annular end wall 17a to both ends of an outer cylinder 17b and an inner cylinder 17c, and a magnet support 20 is integrally connected to the right half of the outer cylinder 17b and the right end wall 17a. Ru. A circuit switching member 37 is supported by a pair of bearings 18 on the right half of the inner cylinder 17c.

As shown in FIG. 3, a magnet support 20 made of a non-magnetic material connects a large number of permanent magnets 32 and integrally V-shaped magnetic pole members 31 at equal intervals in the circumferential direction. The base end of the magnetic pole material 31 faces the inner circumferential surface of the brake drum 13 , and the bifurcated tip faces the outer circumferential surface of the circuit switching member 37 . Permanent magnet 32
are connected to one tip of the magnetic pole material 31, and are arranged so that the polarity with respect to the outer peripheral surface of the circuit switching member 37 is alternately different in the circumferential direction. Preferably, the permanent magnet 3 of the magnetic pole material 31
One tip including 2 extends radially inward (to the axis). The circuit switching member 37 has the same number of U-shaped ferromagnetic materials 35 as the magnetic pole materials 31 described above coupled at equal intervals in the circumferential direction, and both ends of the ferromagnetic materials 35 are attached to the tip of the magnetic pole material 31 in two postures or switching positions. It is said that it is possible to face each other.

As shown in FIG. 1, the circuit switching member 37 is rotated by a half pitch of the arrangement pitch p (FIG. 3) of the magnetic pole material 31 to switch the relative position between the magnetic pole material 31 and the ferromagnetic material 35. A rotational drive means 50 is disposed between the fixed frame 17 and the circuit switching member 37. A cylindrical portion 37a is integrally formed at the left end of the circuit switching member 37, and a gear 37b is formed on the outer peripheral surface of the cylindrical portion 37a. End wall 17 of fixed frame 17
A gear 42 rotationally driven by an electric motor 41 supported at a
is meshed with gear 37b. Next, the operation of the eddy current speed reduction device according to the present invention will be explained. The brake drum 13 rotates together with the rotating shaft 4 as the vehicle travels. As shown in FIG. 3, both ends of each ferromagnetic material 35 are connected to each magnetic pole material 3.
In the non-braking position facing the bifurcated tip of the brake drum 1, a short magnetic circuit is created between the magnetic pole material 31 and the ferromagnetic material 35, as shown by the chain line in FIG. 3, and no magnetic field is applied to the brake drum 13. Therefore, the brake drum 13 does not receive any braking force.

During braking, the electric motor 41 causes the circuit switching member 3 to
7 is rotated by a half pitch of the arrangement pitch p of the ferromagnetic materials 35, both ends of each ferromagnetic material 35 straddle the tips of the adjacent magnetic pole materials 31, as shown in FIG. The base end of the magnetic pole material 31 forms magnetic poles whose polarity is alternately different in the circumferential direction, and as shown by the chain line in FIG. form a magnetic circuit that extends over the area. When the rotating brake drum 13 crosses the magnetic field from the magnetic pole material 31, an eddy current flows through the brake drum 13, and the brake drum 13 receives a braking force.

Contrary to the above-described embodiment, similar effects can be obtained by arranging the circuit switching member on the outer circumferential side of the magnet support 20 and the braking drum on the inner circumferential side.

In the embodiment shown in FIGS. 5 and 6, a circuit switching member 37A connects a large number of ferromagnetic materials 35A at equal intervals in the circumferential direction.
Magnet supports 20A, which connect a large number of V-shaped magnetic pole materials 31A and permanent magnets 32A at equal intervals in the circumferential direction, are arranged coaxially between the brake disk 13A as a rotational brake and the magnet supports 20A. One of the circuit switching members 37A is fixed, and the other is rotatable by half a pitch. In the speed reduction device of this embodiment, during braking, on a surface substantially parallel to the circumferential surface of the brake disc 13A,
A magnetic circuit shown by a chain line in FIG. 6 is created between the ferromagnetic material 35A, the magnetic pole material 31A, and the brake disc 13A.

[0015]

Effects of the Invention As described above, the present invention includes a magnet support disposed between the braking rotor and the circuit switching member, and a large number of V-shaped magnetic pole materials arranged at equal intervals in the circumferential direction on the magnet support. are arranged in parallel to face the braking rotor, permanent magnets are connected to one leg of the forked tip of each magnetic pole material so that the polarity alternately differs in the circumferential direction, and both ends of the bifurcated tip of each magnetic pole material are connected to U-shaped ferromagnetic materials facing each other are arranged side by side on the circuit switching member at equal intervals in the circumferential direction, and both ends of each ferromagnetic material of the circuit switching member are aligned with the non-braking position facing the bifurcated tip of each magnetic pole material. The braking position, which straddles the tips of adjacent magnetic pole materials and faces each other, is equipped with a rotary drive means that causes relative rotation between the magnet support body and the circuit switching member, so switching between non-braking and braking is possible at the magnet support. This is achieved by the rotation of the circuit switching member without the axial movement of the body. Therefore, the overall axial dimension is significantly shortened compared to the conventional example, making it easier to mount it on a vehicle.

Compared to the conventional example, there is more room for installation in the vehicle, and by increasing the size of the permanent magnet, the braking force can be increased, and the specifications (
It is possible to manufacture products with different braking forces, and is advantageous in terms of cost, weight, etc.

[0017] If the device is assembled by assembling the circuit switching member in the non-braking position on the magnet support with an appropriate spacer in between, that is, in a state where a short magnetic circuit is created between the two, it is possible to The magnetic force of the permanent magnet does not reach the constituent members, and does not interfere with the mutual assembly of the constituent members.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view of an eddy current speed reduction device according to the present invention.

FIG. 2 is a front sectional view showing a rotational drive means of the device.

FIG. 3 is a front sectional view showing the device in a non-braking state.

FIG. 4 is a front sectional view showing the braking state of the device.

FIG. 5 is a perspective view of an eddy current reduction gear according to a second embodiment of the present invention.

FIG. 6 is a plan view showing the device expanded in the circumferential direction.

[Explanation of symbols]

Claims (1)

[Claims] Claim 1: A magnet support is disposed between the brake rotor and the circuit switching member, and a large number of V-shaped magnetic pole members are arranged on the magnet support at equal intervals in the circumferential direction so that the base end faces the brake rotor. U-shaped ferromagnetic magnets are arranged side by side, and permanent magnets are coupled to one leg of the bifurcated tip of the magnetic pole material so that the polarity alternately differs in the circumferential direction, and both ends are opposite to the bifurcated tip of each magnetic pole material. The ferromagnetic materials are arranged side by side on the circuit switching member at equal intervals in the circumferential direction, and both ends of each ferromagnetic material of the circuit switching member straddle the tip of the magnetic pole material adjacent to the non-braking position where it faces the bifurcated tip of each magnetic pole material. What is claimed is: 1. An eddy current speed reduction device comprising: a rotational drive means for causing relative rotation between a magnet support and a circuit switching member at braking positions that face each other.