JP2709821B2 - 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 a 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).

Problems to be Solved by the Invention Since the conventional eddy current type speed reducer 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. In addition, when braking is ON, it is normally necessary to 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.

The present invention aims to eliminate such problems,
It is an object of the present invention to provide an eddy current type speed reducer that requires only a short period of time for braking.

Means for Solving the Problems To achieve the above object, in an eddy current type reduction gear transmission, a rotor is fitted to one end of a rotating shaft, and a magnetic shield casing having a cylindrical portion separated from the rotor is attached to the rotor. A support ring in which a plurality of permanent magnets are provided so as to be adjacently fixed and arranged so that the polarities of the adjacent magnets are opposite to each other, and the pole faces of the permanent magnets in the axial direction of the rotation shaft are provided with a required gap. An object of the present invention is to provide a length from a position entirely opposed to the rotor to a position of a magnetic shield casing detached entirely from the rotor so as to be movable forward and backward.

It is desirable to use a rare earth magnet having excellent magnetic properties, such as a rare earth cobalt magnet or a rare earth / iron / boron magnet, as the permanent magnet.

Action When the support ring surrounding the permanent magnets of the speed reducer constructed as described above is moved to make the permanent magnets face the rotor entirely, a vortex is generated in the rotor by a magnetic circuit configured between adjacent permanent magnets. Electric current flows and a large braking torque is generated.

If the permanent magnet facing the rotor is gradually retracted, the generated braking torque is gradually reduced, and the braking force is reduced. If the permanent magnet is completely retracted and completely separated from the rotor, braking is released.

Embodiment An embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, a rotor (3) having a U-shaped cross section and having cooling fins (2) on its outer peripheral surface is fitted to one end of the rotating shaft (1). ), A plurality (three in the drawing) of support members (5) projecting radially and axially extending from the bearing housing (4) supported by
Guide rails (6) are attached to the top surfaces of the support members (5). A slide saddle (8) is provided on the inner peripheral surface of a support ring (7) having a cylinder length corresponding to the cylindrical portion of the rotor (3) so as to extend over the guide rail (6). (6) It is provided so that it can move up and down with respect to the rotor (3). On the outer peripheral surface of the support ring (7), a plurality of permanent magnets (10) made of a rare earth magnet with a pole piece (9) adhered thereto (in the drawing,
Twelve (even number) cases are provided so that the magnetic poles of adjacent magnets are opposite to each other.

On the extension of the cylindrical portion of the rotor (3), a cylinder (11) having the same inner diameter is provided on a lid plate (12) attached to the end face of the bearing housing (4) separately from the rotor (3). , Cylindrical (1
1) and cover plate (12) form a magnetic shield casing,
It is configured so that magnetism does not leak out of the device.

In addition, the rotor (3) and the cylinder (11) forming the casing are both made of a material (for example, Fe, etc.) that easily transmits magnetic flux.
, The permanent magnet (10) can smoothly move forward and backward. The configuration of the casing is not limited to the one shown in the embodiment, but has a magnetic shielding effect and a permanent magnet (1
Any configuration can be arbitrarily selected as long as the configuration does not hinder advance / retreat of 0). And, 3 provided on the inner peripheral surface of the support ring (7)
A nut (13) protrudes from each intermediate point of the two slide saddles (8), and one end of a screw rod (14) screwed to this nut is connected to a bearing (15) attached to the cover plate (12). Support. A gear (16) is provided near the shaft support end of the screw rod (14), and meshes with a large-diameter intermediate gear (18) that is supported by a bearing (17) in a bearing housing (4). In addition, the intermediate gear (18) is
Drive gear (2) provided on the main shaft of motor (19) attached to 2)
0) (see FIG. 4).

The speed reducer is a mounting bracket (21) provided on the cylinder (11).
Is attached to the vehicle body, and both ends of the rotating shaft (1) are connected to the middle of the propeller shaft via a cross joint.

As shown in FIG. 3, when the support ring (7) is retracted and the group of permanent magnets is separated from the rotor (3), no eddy current flows in the rotor (3). The rotor (3) is rotating with a predetermined torque and is in a so-called brake OFF state.

When the motor (19) is started with the brake off, the screw rod (14) rotates via the drive gear (20), the intermediate gear (18) and the gear (16) and is supported via the nut (13). The ring (7) advances toward the rotor (3), and finally the entire surface of the pole piece (9) faces the cylindrical inner surface of the rotor (3) via a predetermined gap. At this time, the maximum braking torque is obtained, and the vehicle is greatly decelerated.

The motor (1
When the support ring (7), that is, the group of permanent magnets is retreated, the braking torque is reduced as the facing area between the rotor and the permanent magnet is reduced, and the brake shown in FIG. Return to the OFF state.

Therefore, when the braking force is small, it is only necessary to increase or decrease the movement of the magnet so that the facing area between the permanent magnet and the rotor is located at an intermediate position between the overall correspondence and the entire separation. The control may be performed by incorporating various position sensors (not shown) and controlling the driving of the motor. In the above embodiment, the configuration in which the pole piece is adhered to the magnet pole surface is shown, but the pole piece is not an indispensable member for achieving the present invention.

FIG. 5 shows the results of the control torque test. That is, at each vehicle speed, the braking torque was measured for the case where the rare earth magnet was made to correspond to the entire surface, the case where it was made to correspond to the 3/4 surface, and the case where it was made to correspond to the 1/2 surface.

Further, although the forward and backward movement of the permanent magnet utilizes the screw force by the screw rod and the nut, other mechanisms can be used without being limited to this.

Effect of the Invention The present invention is configured as described above, and the braking torque generated by changing the corresponding area between the rotor and the permanent magnet can be adjusted, so that the braking force can be easily controlled and can be applied to a wide range of deceleration.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a speed reduction device according to an embodiment of the present invention in a braking state, FIG. 2 is a side view on line AA in FIG. 1, FIG. 3 is a longitudinal sectional view in an unbraking state, and FIG. FIG. 1 is an explanatory view schematically showing a drive system for moving a support ring having a group of permanent magnets back and forth in a right side view of FIG. 1, and FIG. 5 is a graph showing a relationship between a vehicle speed and a braking torque of a speed reducer using a rare earth magnet. It is. DESCRIPTION OF SYMBOLS 1 ... Rotating shaft 2 ... Cooling fin 3 ... Rotor 4 ... Bearing box 5 ... Support member 6, Guide rail 7 ... Support ring 8, Slide saddle 9 ... Pole piece, 10 ... permanent magnet 11 ... cylinder, 12 ... lid plate 13 ... nut, 14 ... threaded rod 15 ... bearing, 16 ... gear 17 ... bearing, 18 ... intermediate gear 19 ... motor, 20 ...... Driving gear

Continued on the front page (72) Inventor Takashi Kobayashi 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Sumitomo Special Metals Co., Ltd. Yamazaki Works 40-327 (JP, B1) Jiko 53-9810 (JP, Y1)

Claims (1)

(57) [Claims] 1. A rotor is fitted to one end of a rotating shaft, and a magnetic shield casing having a cylindrical portion separated from the rotor is fixedly arranged adjacent to the rotor, and the polarity of adjacent magnets is opposite to each other. The length of the support ring, in which a plurality of permanent magnets are provided in a circumferential direction, from the position where the pole faces of the permanent magnets are completely opposed to the rotor with a required gap in the axial direction of the rotation shaft to the position of the magnetic shield casing where the entire surface is separated. An eddy current type reduction gear that is provided so that it can move forward and backward.