JPH0695826B2 - Eddy current type speed reducer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current type speed reducer mainly for assisting a friction brake of a large vehicle, and more particularly to an eddy current type speed reducer capable of shortening an axial dimension.

[0002]

2. Description of the Related Art In an eddy current type speed reducer disclosed in Japanese Patent Laid-Open No. 1-234043, a magnet supporting ring for coupling a large number of permanent magnets at equal intervals in the circumferential direction is attached to a fixed frame protruding inside a braking drum by an actuator. The magnet support ring protrudes into the braking drum so that the permanent magnet exerts a magnetic field on the inner peripheral surface of the braking drum, and the permanent magnet retracts from the braking drum to cause the permanent magnet to move inside the braking drum. It is switched to a non-braking position where no magnetic field is applied to the peripheral surface.

In the above-mentioned eddy current type speed reducer, the axial dimension of the fixed frame is long, and for example, the speed reducer and the parking brake are installed in a narrow mounting space of the connecting portion between the output rotary shaft and the propulsion shaft of the transmission under the floor of the vehicle body. There are various difficulties in arranging in. Further, if the inner diameter of the braking drum is not changed and the circumferential dimension of the permanent magnets is increased in order to increase the braking ability, the amount of magnetic leakage due to the mutual approach of the permanent magnets increases. Therefore, if the dimension of the permanent magnet in the axial direction is lengthened, not only the fixed frame but also the actuator that drives the magnet support ring needs to have a long stroke. Not preferable. Further, there is a disadvantage in that the permanent magnet of the magnet supporting ring exerts a magnetic force on the constituent members during the assembly of the apparatus, which hinders the assembly work.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an eddy current type speed reducer in which a movable component can be stably assembled without being affected by the magnetic force of a permanent magnet and the overall axial dimension can be shortened. Especially.

[0005]

In order to achieve the above object, the structure of the present invention is such that a magnet support is disposed between the braking rotor and the circuit switching member, and the magnet support is circumferentially equidistant. A large number of V-shaped magnetic pole members are arranged side by side so that their base ends face the braking rotor, and permanent magnets are coupled to one leg of the bifurcated tip of the magnetic pole members so that their polarities alternate in the circumferential direction. U-shaped ferromagnetic materials, both ends of which are opposed to the forked ends of each magnetic pole member, are arranged in parallel in the circuit switching member at equal intervals in the circumferential direction, and both ends of each ferromagnetic material of the circuit switching member are bifurcated. The rotary drive means for causing relative rotation between the magnet support and the circuit switching member is provided at a non-braking position facing the tip of the magnetic pole member and a braking position facing the tip of the adjacent magnetic pole member across the magnetic pole member.

[0006]

A large number of magnetic poles that are V-shaped integrally with the permanent magnet are provided between the rotary braking body and the circuit switching member that connects the plurality of U-shaped ferromagnetic materials facing the rotary braking body at equal intervals in the circumferential direction. A magnet supporting member that connects the members at equal intervals in the circumferential direction is coaxially arranged, and the circuit switching member is rotatable with respect to the magnet supporting member by a half pitch. At the non-braking position where the bifurcated tips of the magnetic pole members of the magnet support face the opposite ends of the ferromagnetic members of the circuit switching member, the V-shaped magnetic pole member including the permanent magnet and the U-shaped ferromagnetic member are short-circuited. Since the magnetic circuit is generated and does not exert a magnetic field on the rotary braking body, the rotary braking body is not subjected to the 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 straddling the rotary braking body is generated between the base ends of the adjacent magnetic pole members. When the rotary braking body crosses the magnetic field from the magnetic pole material, an eddy current flows through the rotary braking body, and the rotary braking body receives a braking force.

[0008]

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

The inner peripheral surface of the braking drum 13 and the braking drum 16
A cylindrical fixed frame 17 made of a non-magnetic material is arranged in a space between the outer peripheral surface and the outer peripheral surface. Therefore, the circular frame plate 15 having the reinforcing ribs 15 a is fixed to the rear end wall of the transmission 2 via the mounting plate 14, and the fixed frame 17 is fixed to the frame plate 15.
The fixed frame 17 is configured 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 a right half portion and a right end wall 17a of the outer cylinder 17b. It The circuit switching member 37 is supported by the pair of bearings 18 on the right half of the inner cylinder 17c.

As shown in FIG. 3, the magnet support 20 made of a non-magnetic material is composed of a large number of permanent magnets 32 and V-shaped magnetic pole members 31 which are integrally formed with each other at regular intervals in the circumferential direction. The base end of the magnetic pole material 31 faces the inner peripheral surface of the braking drum 13, and the bifurcated front end faces the outer peripheral surface of the circuit switching member 37. Permanent magnet 32
Is connected to one end of the magnetic pole member 31 and is arranged such that the polarity of the circuit switching member 37 with respect to the outer peripheral surface is alternately different in the circumferential direction. Preferably, the permanent magnet 3 of the magnetic pole material 31
One end including 2 extends radially inward (axial center). The circuit switching member 37 connects the same number of U-shaped ferromagnetic materials 35 as the above-described magnetic pole material 31 at equal intervals in the circumferential direction, and both ends of the ferromagnetic material 35 are attached to the tip of the magnetic pole material 31 in two positions or switching positions. 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 relational position between the magnetic pole material 31 and the ferromagnetic material 35. In addition, the rotation driving means 50 is arranged 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 which is rotationally driven by an electric motor 41 supported by a.
Is meshed with the gear 37b. Next, the operation of the eddy current type speed reducer according to the present invention will be described. The braking drum 13 rotates together with the rotary 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 31.
In the non-braking position opposed to the bifurcated tip of the, the short-circuit magnetic circuit is generated 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 exerted on the braking drum 13. The braking drum 13 does not receive the braking force.

During braking, the circuit switching member 3 is driven by the electric motor 41.
When 7 is rotated by a half pitch of the arrangement pitch p of the ferromagnetic material 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 having different polarities alternately in the circumferential direction, and as shown by a chain line in FIG. 4, each ferromagnetic material 35 passes through a pair of adjacent magnetic pole materials 31 to the braking drum 13. Form a magnetic circuit that extends. When the rotating braking drum 13 crosses the magnetic field from the magnetic pole material 31, an eddy current flows through the braking drum 13, and the braking drum 13 receives a braking force.

Contrary to the above-mentioned embodiment, the same effect can be obtained by disposing the circuit switching member on the outer peripheral side of the magnet support 20 and the braking drum on the inner peripheral side.

In the embodiment shown in FIGS. 5 and 6, a circuit switching member 37A for coupling a large number of ferromagnetic materials 35A at equal intervals in the circumferential direction.
And a braking disc 13A serving as a rotation braking body, a plurality of V-shaped magnetic pole members 31A and permanent magnets 32A are coaxially arranged with a magnet support 20A for coupling the permanent magnets 32A at equal intervals in the circumferential direction. One of the circuit switching members 37A is fixed, and the other is rotatable by a half pitch. In the speed reducer of this embodiment, at the time of braking, on the surface substantially parallel to the peripheral surface of the braking disc 13A,
A magnetic circuit shown by a chain line in FIG. 6 is generated between the ferromagnetic material 35A, the magnetic pole material 31A, and the braking disk 13A.

[0015]

As described above, according to the present invention, the magnet support is disposed between the braking rotor and the circuit switching member, and a large number of V-shaped magnetic pole members are provided at the base of the magnet support at equal intervals in the circumferential direction. Are arranged side by side so as to face the braking rotor, and a permanent magnet is coupled to one leg of the bifurcated tip of the magnetic pole member so that the polarities are alternately different in the circumferential direction. 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 in phase with the non-braking position where they oppose the bifurcated tips of the magnetic pole members. Since a rotation drive means for causing relative rotation between the magnet support and the circuit switching member is provided at a braking position across the tips of the adjacent magnetic pole members and facing each other, switching between non-braking and braking is supported by the magnet. It is reached by the rotation of the circuit switching member regardless of the axial movement of the body, and therefore the overall axial direction. Law is greatly reduced as compared with the conventional example, it is easy to mount on the vehicle.

Compared with the conventional example, there is more room in the mounting space of the vehicle, the braking force can be increased by lengthening the dimension of the permanent magnet, and products with different specifications (braking force) can be obtained without changing the rotary braking body. It can be manufactured and is advantageous in terms of cost and weight.

By assembling the device after previously combining the circuit switching member in the non-braking position on the magnet support with a suitable spacer interposed therebetween, that is, in a state where a short-circuiting magnetic circuit is generated between the two, The magnetic force of the permanent magnet does not reach the constituent members of (1) and the assembly of the constituent members is not hindered.

[Brief description of drawings]

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

FIG. 2 is a front sectional view showing a rotation driving means of the apparatus.

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

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

FIG. 5 is a perspective view of an eddy current type speed reducer according to a second embodiment of the present invention.

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

[Explanation of symbols]

4: Rotating shaft 13, 13A: Braking drum 20, 20
A: magnet support 31, 31A: magnetic pole material 32, 32
A: Permanent magnet 35, 35 A: Ferromagnetic material 37, 37
A: Circuit switching member 50: Rotational drive means

Claims (1)

[Claims] 1. A magnet support is provided between a braking rotor and a circuit switching member, and a large number of V-shaped magnetic pole members are provided on the magnet support at equal intervals in the circumferential direction so that the base end faces the braking rotor. U-shaped ferromagnets that are arranged side by side and have permanent magnets connected to one leg of the bifurcated tips of the pole pieces so that their polarities are alternately different in the circumferential direction, and both ends face the bifurcated tips of the pole pieces. The materials 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 straddle the tip of the magnetic pole material adjacent to the non-braking position facing the bifurcated tip of each magnetic pole material. An eddy current type speed reducer characterized by comprising rotation drive means for causing relative rotation of the magnet support and the circuit switching member at braking positions facing each other.