JPH0695827B2 - 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 An eddy current type speed reducer according to Japanese Patent Application No. 1-218498 uses a actuator to attach a magnet support ring for coupling a large number of permanent magnets at regular intervals in a circumferential direction to a fixed frame protruding inside a braking drum. The magnet support ring is supported so as to be movable in the axial direction, and the magnet support ring protrudes into the inside of the braking drum so that the permanent magnet exerts a magnetic field on the inner peripheral surface of the braking drum. It is switched to a non-braking position where no magnetic field is applied to the inner 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 increased, not only the fixed frame but also the actuator that drives the magnet support ring will need to have a long stroke.
It is not preferable in terms of weight and cost.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the overall axial dimension by not moving the magnet support axially, but by allowing the rotary brake to traverse and cross the magnetic field. An object of the present invention is to provide an eddy current type speed reducer capable of switching to a non-braking state.

[0005]

In order to achieve the above object, the structure of the present invention is such that a magnetic pole support is sandwiched between a braking rotor and a magnet support, and the magnetic pole support is circumferentially mounted. A large number of V-shaped magnetic pole members are arranged in parallel so that their base ends face the braking rotor, and permanent magnets with both poles facing the bifurcated ends of the magnetic pole members are magnetized so that their directions alternate in the circumferential direction. The magnetic pole support and the magnets are arranged side by side on the support body, and at a non-braking position where both poles of each permanent magnet of the magnet support face the tip of each magnetic pole material and at a braking position where the poles of the permanent magnets face each other adjacent to each other. The support is provided with a rotation driving means for causing relative rotation.

[0006]

A magnetic pole support having a large number of V-shaped magnetic pole members at regular intervals in the circumferential direction is provided between the rotary brake and a magnet support having a large number of permanent magnets facing the rotary brake at regular intervals in the circumferential direction. They are arranged coaxially, one of the magnetic pole support and the magnet support is fixed, and the other is rotatable by half a pitch. At the position where the bifurcated tip of each pole member of the pole support faces both poles of each permanent magnet, a short-circuiting magnetic circuit is generated between the pole member and the permanent magnet, and no magnetic field is applied to the rotary braking body, so the rotary braking is performed. The body does not receive braking force.

When the magnetic pole support is rotated by half a pitch with respect to the magnet support, the bifurcated tips of the magnetic pole members straddle the adjacent permanent magnets. That is, since the bifurcated tip of the magnetic pole material faces the magnetic pole having the same polarity, a magnetic circuit straddling the rotary braking body is generated between the magnetic pole materials adjacent to each other. 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 or a magnet support 17 made of a non-magnetic material is arranged in a space between the outer peripheral surface of the magnet support 17 and a large number of permanent magnets 26 in the right half of the magnet support 17 at equal intervals in the circumferential direction. Be combined. The magnet support 17 is fixed to the wall portion of the transmission 2. Therefore, the circular frame plate 15 having the reinforcing ribs 15a is fixed to the rear end wall of the transmission 2 via the mounting plate 14, and the frame plate 1
The magnet support 17 is fixed to the magnet 5.

As shown in FIG. 3, the right half portion of the magnet support 17 is thick and has a horseshoe-shaped permanent magnet 26 embedded therein. Both magnetic poles of the permanent magnet 26 are connected to the outer peripheral surface of the magnet support 17. Exposed. Actually, when casting the magnet support 17, the permanent magnets 26 are cast at equal intervals in the circumferential direction.

As shown in FIG. 1, a magnetic pole support 20 made of a non-magnetic material is rotatably supported by a magnet support 17.
In other words, both end walls 20a and 20b of the magnet support 17 are supported by the magnet support 17 by the pair of bearings 18. The magnetic pole support 20 is provided with an annular groove 22 that straddles the above-mentioned permanent magnet 26 on the inner peripheral wall, and magnetic pole members 25 made of the same number of ferromagnetic materials as the permanent magnets 26 are embedded in the outer peripheral wall at equal intervals in the circumferential direction. As shown in FIG. 3, the pole piece 25 has a V-shaped cross section,
The bifurcated distal end is configured so as to be able to face both poles of each permanent magnet 26, and the proximal end faces the inner peripheral surface of the braking drum 13.

As shown in FIG. 1, in order to rotate the magnetic pole support 20 by a half pitch p of the arrangement pitch of the magnetic pole material 25 and switch the relational position between the magnetic pole material 25 and the permanent magnet 26, the rotation driving means. 50 is the magnet support 17 and the magnetic pole support 2
It is arranged between 0 and. A cylindrical portion 23 is integrally formed at the left end of the magnetic pole support 20, and the gear 2 is provided on the inner peripheral surface of the cylindrical portion 23.
3a is formed. On the other hand, the end wall 17a is integrally formed at the left end of the magnet support 17, and the gear 42 driven to rotate by an electric motor (not shown) supported by the end wall 17a is the gear 2
3a is engaged.

Next, the operation of the eddy current type speed reducer according to the present invention will be described. Braking drum 1 as the vehicle runs
3 rotates together with the rotating shaft 4. As shown in FIG. 3, in the non-braking position where the forked ends of each magnetic material 25 face both poles of each permanent magnet 26, as indicated by the chain line in FIG.
Since a short circuit magnetic circuit is generated between the permanent magnet 26 and the magnetic material 25 and does not exert a magnetic field on the braking drum 13, the braking drum 13 is not subjected to the braking force.

During braking, the magnetic pole support 20 is driven by the electric motor 41.
Is rotated by a half pitch p of the arrangement pitch of the magnetic pole members 25, the bifurcated tips of the magnetic pole members 25 straddle the magnetic poles of the same polarity of the adjacent permanent magnets 26, as shown in FIG. Therefore, the base end of the magnetic pole material 25 forms magnetic poles whose polarities are alternately different in the circumferential direction, and as shown by the chain line in FIG. 4, braking is performed from each permanent magnet 26 through a pair of adjacent magnetic pole materials 25. Form a magnetic circuit that spans the drum 13. When the rotating braking drum 13 crosses the magnetic field from the pole piece 25, the braking drum 1
An eddy current flows through the brake drum 3, and the braking drum 13 receives the braking force.

In the above-mentioned embodiment, the magnet support 17 may be rotatable by a half pitch instead of the magnetic pole support 20, and the magnetic support may be provided on the outer peripheral side of the magnetic pole support 20.
Even if the braking drum is arranged on the inner peripheral side, the same effect can be obtained.

In the embodiment shown in FIG. 5, a large number of permanent magnets 2
Between the magnet support 17A having 6A at equal intervals in the circumferential direction and the braking disk 13A, the magnetic pole supports 20A having many magnetic pole members 25A at equal intervals in the circumferential direction are coaxially arranged to form the magnetic pole support 2
One of the magnet support 17A and the magnet support 17A is fixed, and the other is rotatable by a half pitch. In the speed reducer of this embodiment, during braking, a magnetic circuit is generated between the permanent magnet 26A, the magnetic pole member 25A, and the braking disc 13A on a surface substantially parallel to the peripheral surface of the braking disc 13A.

[0017]

As described above, according to the present invention, a magnetic pole support is sandwiched between a braking rotor and a magnet support, and a large number of V-shaped magnetic pole members are provided at equal intervals in the circumferential direction on the magnetic pole support. The base ends are arranged side by side so as to face the braking rotor, and the bifurcated distal ends of the magnetic pole members are provided side by side with permanent magnets with opposite poles arranged side by side on the magnet support body so that their orientations alternate in the circumferential direction. The rotational drive that causes relative rotation between the magnetic pole support and the magnet support at the non-braking position where the two poles of each permanent magnet face the tip of each magnetic pole member and the braking position where the two poles of the permanent magnet face the tip of each magnetic pole member while straddling the adjacent magnetic pole members. Since the switching between non-braking and braking is achieved by the rotation of the magnetic pole support or the magnet support instead of the axial movement of the magnet support, the overall axial dimension is larger than that of the conventional example. It is greatly shortened and it becomes easy to mount it on the vehicle.

Compared with the conventional example, there is more space in the vehicle mounting space, the braking force can be increased by lengthening the axial dimension of the permanent magnet accordingly, and the specifications (braking force) differ even without changing the rotary braking body. A product can be manufactured, which is advantageous in terms of cost, weight, and the like.

[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 front sectional view showing a modified example of a magnetic pole support.

[Explanation of symbols]

4: rotating shaft 13,13A: braking drum 17,17
A: magnet support 20, 20A: magnetic pole support 25, 2
5A: magnetic pole material 26, 26A: permanent magnet 50: rotation drive means

Claims (1)

[Claims] 1. A magnetic pole support is sandwiched between a braking rotor and a magnet support, and a large number of Vs are arranged on the magnetic pole support at equal intervals in the circumferential direction.
-Shaped pole pieces are installed side by side so that the base ends face the braking rotor.
Permanent magnets with both poles facing each other at the bifurcated ends of the pole pieces are arranged side by side on the magnet support so that their orientations are alternately different in the circumferential direction, and both poles of each permanent magnet of the magnet support face the tips of each pole piece. Eddy current type deceleration, characterized in that the non-braking position and the braking position across the adjacent magnetic pole members are provided with rotation driving means for causing relative rotation between the magnetic pole support and the magnet support. apparatus.