JPH04281361A - Electromagnetic coupling unit - Google Patents

Abstract

PURPOSE:To enhance brake force without enlarging the framework of electromagnetic coupling unit. CONSTITUTION:An electromagnetic coupling unit 1 comprises an exciting means 3 comprising a core 5 and a coil 6, and a permanent magnet 4. The exciting means 3 is arranged such that the end face of the pole 5a of the core 5 opposes through a predetermined air gap G to the inner peripheral face of a cup type rotor 2. A permanent magnet 4 abuts on the side face of a circumferentially adjacent pole 5a at the end of each pole 5a. The permanent magnet 4 is disposed so that the polarity thereof matches with that of the adjacent pole 5a.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic coupling device for braking a rotating body or transmitting driving force to another rotating body.

0002

2. Description of the Related Art In large buses, trucks, etc., foot brakes, engine brakes, exhaust brakes, etc. are used as deceleration means. However, on long downhill slopes, the foot brake is used more frequently, and there is a risk that the braking force will decrease due to wear of the brake lining. Therefore, in order to ensure safety during braking, retarders have begun to be installed as a fourth auxiliary brake.

[0003] Until now, this retarder used a coil type electromagnet or a fluid type, both of which were large and heavy and required major modifications to the vehicle, making it difficult to install them on a vehicle. Met. Therefore, retarders that use permanent magnets to reduce size and weight have been proposed.

0004

[Problems to be Solved by the Invention] This permanent magnet type retarder uses an air piston to move a permanent magnet in and out of the drum.In order to improve the braking force,
The body size increases accordingly.

The present invention was made based on the above-mentioned circumstances, and its object is to provide an electromagnetic coupling device that improves braking force without increasing its size.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention comprises an iron core constituting a magnetic circuit and a coil wound around the iron core, and the iron core is magnetized by energizing the coil. The tip of the magnetic pole constitutes a magnetic pole, and the excitation means is arranged such that the tip surface of the magnetic pole has a predetermined gap with the rotating circumferential surface of the rotating body, and magnetically connects between the magnetic poles on the side of the rotating body from the coil. a permanent magnet disposed in contact with a side surface of the magnetic pole so as to short-circuit the permanent magnet,
The technical means is that the polarity thereof is arranged to be the same as the polarity of the adjacent magnetic pole.

[0007]

In the electromagnetic coupling device of the present invention constructed as described above, when no current flows through the coil, the magnetic flux of the permanent magnet is short-circuited by the iron core and circulates internally. Therefore, no magnetic flux flows through the rotating body that faces the magnetic poles with a predetermined gap therebetween. Therefore, no magnetic force acts on the rotating body and no braking force is generated.

When the coil is energized, magnetic flux due to its magnetomotive force flows between the iron core and the rotating body through the air gap. At this time, the magnetic flux generated by the permanent magnet is repelled by the coil magnetomotive force and cannot circulate internally, but instead flows between the tip of the magnetic pole and the rotating body through the air gap. Therefore, braking force is generated by the magnetic force acting on the rotating body.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electromagnetic coupling device of the present invention will be explained based on an embodiment shown in the drawings. FIG. 1 is a sectional view of an electromagnetic coupling device. The electromagnetic coupling device 1 of this embodiment is used as a braking device for a rotating body 2.

The rotating body 2 is a bowl-shaped ferromagnetic material that rotates by receiving a driving force from a driving source (not shown). The electromagnetic coupling device 1 includes an excitation means 3 that generates magnetic flux during braking, and a permanent magnet 4. The excitation means 3 includes an iron core 5 constituting a magnetic circuit and a coil 6 wound around the iron core 5.

The iron core 5 has a cross-shaped cross section, and becomes a four-pole electromagnet when it is magnetized by energizing the coil 6. The iron core 5 is arranged such that the tip end surface of each magnetic pole 5a faces the inner circumferential surface of the rotating body 2 with a predetermined air gap G (air gap according to the present invention) therebetween.

The permanent magnet 4 is disposed between circumferentially adjacent magnetic poles 5a on the tip side of each magnetic pole 5a (on the rotating body 2 side from the coil 6), and is used to magnetically short-circuit between the magnetic poles 5a. ,
Each is in contact with the side surface of the magnetic pole 5a. This permanent magnet 4 is arranged so that its polarity is the same as that of the adjacent magnetic pole 5a. For example, if one magnetic pole 5a of the iron core 5 magnetized by energizing the coil 6 is an S pole, the permanent magnet 4 is arranged so that the polarity of the side adjacent to this magnetic pole 5a is the S pole. Ru.

Next, the operation of this embodiment will be explained. coil 6
When no current flows, the magnetic flux Φ1 of the permanent magnet 4 is short-circuited by the iron core 5 and circulates internally as shown by the broken line Φ1 in FIG. Therefore, magnetic flux does not flow to the rotating body 2 facing each other through the air gap G, and no magnetic force acts on the rotating body 2, so no braking force is generated on the rotating body 2.

When the coil 6 is energized, a magnetic circuit is formed between the iron core 5 and the rotating body 2, and a magnetic flux Φ2 due to the magnetomotive force is generated.
However, as shown by the solid line Φ2 in Fig. 1, the air gap G
It flows between the iron core 5 and the rotating body 2 via. At this time,
The magnetic flux Φ1 caused by the permanent magnet 4 is repelled by the magnetomotive force of the coil 6 and cannot be circulated internally as described above, and the solid line Φ1 in FIG.
As shown, the air flows between the tip of the magnetic pole 5a and the rotating body 2 via the air gap G.

Therefore, the magnetic force accompanying the magnetic flux Φ2 from the coil 6 and the magnetic flux Φ1 from the permanent magnet 4 acts on the rotating body 2, and the magnetic force acts as a braking force on the rotating body 2, decelerating or stopping the rotating body 2. let

[0016]

As described above, in the present invention, a large braking force can be generated by arranging the permanent magnet 4 between the magnetic poles 5a of the iron core 5 and energizing the coil 6. Therefore,
There is no need to move the permanent magnet 4 in and out using an air piston as in the past, and the structure can be simplified, and the braking force can be improved without increasing the size.

Next, a second embodiment of the present invention will be described. FIG. 2 is a longitudinal (axial direction) cross-sectional view of the electromagnetic coupling device 1. As shown in FIG. This electromagnetic coupling device 1 has an excitation means 3 in which a pair of disk-shaped iron cores 5 are butted against each other in the axial direction, and a coil 6 is wound around a cylindrical portion 5b formed at the center thereof.

The rotating body 2 is made of a bowl-shaped ferromagnetic material, as in the first embodiment. The iron core 5 has a predetermined air gap G between its outer peripheral surface and the inner peripheral surface of the rotating body 2.
It is located with a The permanent magnet 4 is provided between the magnetic poles 5a of the opposing iron cores 5 at the outer periphery of the coil 6, and is arranged so that its polarity is the same as that of the adjacent magnetic pole 5a.

When no current flows through the coil 6, the magnetic flux Φ1 of the permanent magnet 4 is short-circuited by the iron core 5 and circulates internally as shown by the broken line Φ1 in FIG. Therefore, magnetic flux does not flow to the rotating body 2 facing each other through the air gap G, and no magnetic force acts on the rotating body 2, so no braking force is generated on the rotating body 2.

When the coil 6 is energized, a magnetic circuit is formed between the iron core 5 and the rotating body 2, and a magnetic flux Φ2 due to the magnetomotive force is generated.
However, as shown by the solid line Φ2 in Fig. 2, the air gap G
It flows between the iron core 5 and the rotating body 2 via. At this time,
The magnetic flux Φ1 caused by the permanent magnet 4 is repelled by the magnetomotive force of the coil 6 and cannot be circulated internally as described above, and the solid line Φ1 in FIG.
As shown, the air flows between the tip of the magnetic pole 5a and the rotating body 2 via the air gap G.

Therefore, the magnetic force accompanying the magnetic flux Φ2 from the coil 6 and the magnetic flux Φ1 from the permanent magnet 4 acts on the rotating body 2, and the magnetic force acts as a braking force on the rotating body 2, decelerating or stopping the rotating body 2. let

Next, a third embodiment of the present invention will be described. FIG. 3 is a half-sectional view of the electromagnetic coupling device 1 in the axial direction. This electromagnetic coupling device 1 has a structure in which an excitation means 3 and a permanent magnet 4 are arranged around the outer periphery of a rotating body 2.

The annular excitation means 3 is supported by a frame 7 at both ends in the axial direction, and is fastened and fixed with bolts 8. The permanent magnet 4 is arranged at the center of the inner circumferential side of the iron core 5, which has a substantially U-shaped cross section.

The rotating body 2 is rotatably supported by the frame 7 via a bearing 9, and is disposed with a predetermined air gap G between it and the inner circumferential surfaces of the iron core 5 and the permanent magnets 4. In the case of this embodiment as well, by energizing the coil 6, the permanent magnet 4
The magnetic flux of the coil 6 and the magnetic flux of the coil 6 flow to the rotating body 2, and a braking force is applied to the rotating body 2 due to the action of the magnetic force.

In the above embodiment, the electromagnetic coupling device 1 is used as a braking device, but by connecting another rotating body to the excitation means 3, the rotational force of the rotating body 2 can be transmitted to the other rotating body. It is also possible to use it as a driving force transmission device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electromagnetic coupling device.

FIG. 2 is a longitudinal sectional view of an electromagnetic coupling device showing a second embodiment.

FIG. 3 is a half-sectional view of an electromagnetic coupling device showing a third embodiment.

[Explanation of symbols]

1 Electromagnetic coupling device 2 Rotating body 3 Excitation means 4 Permanent magnet 5 Iron core 5a Magnetic pole 6 Coil G Air gap

Claims (1)

[Claims] Claim 1: a) A magnetic circuit is comprised of an iron core and a coil wound around the iron core, wherein the tip of the iron core is magnetized by energizing the coil and forms a magnetic pole, and the tip of the magnetic pole is excitation means arranged with a predetermined gap from the rotating peripheral surface of the rotating body; b) excitation means that is closer to the rotating body than the coil and comes into contact with a side surface of the magnetic poles so as to magnetically short-circuit between the magnetic poles; an electromagnetic coupling device comprising: a permanent magnet arranged so that the polarity of the permanent magnet is the same as that of the adjacent magnetic pole;