JPS645168B2 - - Google Patents

Description

Detailed Description of the Invention The present invention utilizes the shear resistance of the powder generated by enclosing magnetic powder in a gap formed by a pair of rotating bodies or a rotating body and a fixed body and magnetizing the powder. The present invention relates to a magnetic coupling device that transmits torque or performs a braking action.

This type of coupling device is a friction type disc clutch,
Although it is superior to brakes in that it has anti-slip characteristics, its torque capacity at the same outer diameter is about 1/3 to 1/4, making it dimensionally larger for the same torque.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic coupling device of this type that is compact and capable of generating high torque.

First, a generally known device of this type will be explained with reference to FIG. In the figure, 1 is a yoke that accommodates a coil 2 and is supported by left and right brackets 3 and 4. Reference numeral 5 denotes an outer rotary body connected to the rotating shaft 6 by a right side wall portion, and has a cylindrical portion 7, and this portion is magnetically divided into left and right sides by a non-magnetic blocking ring 8 interposed in the center. The rotating shaft 6 is supported by the right bracket 4 via a bearing 9.
Reference numeral 10 denotes an inner rotating body surrounded by an outer rotating body 5, and there is a gap between the outer peripheral surface and the inner circumferential surface of the cylindrical part 7 of the rotating body 5, and the magnetic powder 11 is inside this gap. Enclosed. The illustrated device is used as a brake, and the inner rotating body 10 is attached to the left bracket 3 in order to function as a braking body.
The bracket is integrally connected to the brake and is secured in place on the machine in which the brake is used so that it does not rotate during operation. Further, in this case, the rotating shaft 6 becomes a braked shaft and is connected to a braked body (not shown).

The conventional coupling device is constructed as described above, and when a current is supplied to the coil 2, a magnetic flux is generated, which is shown by the broken line in the figure, and the magnetic flux flows between the particles of the magnetic powder 11 as well as between the powder and the magnetic powder contained therein. A magnetic attraction force is generated between the circumferential walls constituting the gap, which causes shear resistance between the magnetic powder particles and applies braking to the inner rotating body 10 and, therefore, to the braked body connected to the rotating shaft 6 integral therewith. is applied.

In such a conventional coupling device, the inner rotating body 10
Since the contact surface with the magnetic powder 11 is only the outer peripheral surface of the rotating body, only a restraining force on the rotating body 10 when the magnetic powder 11 is magnetized, and hence only a small braking force can be exerted.

In view of this, the present invention doubles the braking force or torque capacity when used as a clutch by creating a magnetic coupling force on both the inner and outer peripheral surfaces of a member corresponding to one rotating body. An embodiment in which the present invention is applied to a brake will be described below with reference to FIG. In the figure, reference numeral 12 denotes a yoke that accommodates the coil 13, and magnetic pole portions 14, 1 are provided on the inner circumference of the yoke, each extending toward the center from both sides of the yoke.
4' is the same as the structure of the conventional yoke described above, but in this embodiment, a non-magnetic cutoff ring 15 is joined across the tips of both magnetic pole parts, and this ring and the inner peripheral surface of both magnetic pole parts are joined. It constitutes one wall surface of a gap for enclosing magnetic powder, which will be described later. 16,17
The left and right brackets are made of non-magnetic material and support both ends of the yoke 12 at their peripheral edges, and one of the brackets is fixed in place on the machine in which the brake is used, so that it does not rotate together with the yoke portion during operation. ing. Reference numeral 18 denotes a rotating body having a T-shaped cross section, which is integrated with the rotating shaft 19 at the boss portion of the disk-shaped portion, and a permanent magnet ring 20 in the center of the cylindrical portion.
A gap is formed between the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the magnetic pole portions 14, 14', and the magnetic powder 21 is filled in this gap. Rotating axis 1
9 connects each bracket 16, via bearings 22, 22'.
Supported by 17. In the above description, the permanent magnet ring 20 may be interposed only in the center of the cylindrical portion of the rotating body 18, but it may also be provided over a part of the disc-shaped portion. Reference numerals 23 and 23' denote annular magnetic pole bodies fixed to the insides of the brackets 16 and 17, forming a gap between each outer peripheral surface and the inner peripheral surface of the cylindrical part of the rotating body 18, and magnetic powder is placed in this gap. A body 24 is enclosed. 25, 25' and 26, 26' are seals, and the seals 25, 25' are inserted into recesses on the inner surfaces of the magnetic pole bodies 22 and 22', and lightly contact the disc-shaped portion of the rotating body 18. 26' is the magnetic pole body 22
and 22' into the recesses on the inner circumferential surface of the rotary shaft 1.
9 and prevents the magnetic powder 24 from flowing out together with the seals 25 and 25'.

The embodiment of the present invention is configured as described above, and the coil 13
When power is supplied, a magnetic flux flows in the magnetic path shown by the broken line, and the magnetic powders 24 and 21 sealed in the gap on the inner and outer circumferential surface of the cylindrical part of the rotating body 18 are magnetized. The rotation of the rotating body 18 is restrained by the shear resistance acting between the particles of the magnetic powder, and therefore, a brake is applied to a braked body (not shown) connected to the rotating body via the rotating shaft 19.

At this time, if the permanent magnet ring 20 is magnetized so that its polarity is opposite to the direction in which the magnetic flux flows from the coil, the magnetic flux in the cylindrical part of the rotating body having a T-shaped cross section will be permanent near the periphery of the disc-shaped part. Because it is blocked by the magnet ring 20, the flow passes through the magnetic powder 24, the magnetic pole bodies 23, 23', and the center portion of the disc-shaped portion of the rotating body 18, as shown by the arrow, and exerts a predetermined restraining force. Occur.

In addition, if the direction of the current is switched to feed the coil 13 and the direction of the magnetic flux generated by the coil is reversed to that shown in the figure, the magnetic flux will be in the same direction as the magnetic flux caused by the permanent magnet shown by the dashed line in the figure. When the cross section of the cylindrical part of the rotating body 18 is sufficiently large, almost all of the magnetic flux generated by the coil is transferred to the ring 2.
If the design is such that it can pass through the 0 part, the magnetic flux from the coil will flow through the magnetic powder 24, the magnetic pole bodies 23, 2
3', and the magnetic circuit formed by the central part of the disc-shaped part of the rotating body 18, that is, the magnetic circuit with a large reluctance with an intervening air gap. The force is weak, and the binding force at this time is generated only by the magnetic powder 21.

Comparing the two energization states to the coil, in the former there are four working gaps on the left and right outer peripheries of the cylindrical part of the rotating body 18, and in the latter there are two working gaps on the left and right outer peripheries of the cylindrical part. The generated torque is 1/2 in the latter compared to the former.

The embodiment has been described in the case of a brake, but when used as a clutch, the yoke side is not fixed, and the yoke side is connected to the driven side, for example, and at the same time, the rotating shaft 19, which is the other rotating side, is connected to the driving side. Therefore, it goes without saying that when supplying current to the coil 13 or cutting off the power supply, power transmission is performed or interrupted.

In the present invention, as described above, the rotating body 18 is formed to have a T-shaped cross section, and the left and right cylindrical wings, which are the left and right cylindrical wings, are magnetically divided by a ring of permanent magnets, and both sides of the disc-shaped part of the rotating body are A magnetic pole body is provided respectively in the
A gap is formed between the outer circumferential surface of the magnetic pole body and the inner circumferential surface of the cylindrical portion of the rotating body, and magnetic powder is sealed in this gap, and at the same time, the outer circumferential surface of the cylindrical portion of the rotating body is connected to the yoke. The working gap that generates a restraining force on the rotating body 18 when the magnetic powder is magnetized is the There are two locations on the inner and outer circumferential surfaces of the cylindrical part of the rotating body, and magnetic coupling forces are generated on both the inner and outer circumferential surfaces of the cylindrical part of the rotating body, thereby preventing the conventional outward rotation shown in Fig. 1. Compared to the case where magnetic bonding force is generated only at one place on the inner circumferential surface of the body, the constraint is twice as strong when the average diameter of the peripheral wall that makes up the gap, the shear resistance due to magnetization, and the gap width are the same. It is possible to provide a small magnetic coupling device with a large capacity, which can have a braking force or torque capacity, and furthermore, by reversing the direction of excitation of the coil, the generated torque can be halved. Therefore, the current adjustment range is doubled,
At the same time, the torque adjustment range is doubled, and at the same time, the adjustment range of the current adjustment device can be reduced, making it easier to downsize and simplify the control device.

Furthermore, since the rotating body is formed with a T-shaped cross section, the cylindrical part of the rotating body is supported by the disk-shaped part at the center, that is, the cylindrical part of the rotating body has a dimension smaller than that of the supporting part. This means that the cylindrical part is distributed equally to the left and right sides, and the roundness and concentricity of this cylindrical part are easily maintained over the entire width with respect to the support part. This type of electromagnetic coupling device is easy to use and can reduce processing costs.Although this type of electromagnetic coupling device can be used in a slip state, on the other hand, the amount of heat generated in the operating gap that encloses the magnetic powder is large, making it particularly difficult to use. If the generated torque is large, such as the device according to the present invention, the amount of generated heat will further increase, but the heat flow path for the dissipation of this generated heat is distributed almost equally on both sides of the bracket because the configuration of each part is symmetrical. It is also advantageous in terms of heat dissipation ability.

[Brief explanation of drawings]

FIG. 1 is a front view with the upper half of a conventional magnetic coupling device in cross section, and FIG. 2 is a front view of an embodiment of the present invention with the upper half in cross section. 12... Yoke, 14, 14'... Magnetic pole part, 1
5...Nonmagnetic blocking ring, 18...Rotating body, 19
... Rotating shaft, 20 ... Permanent magnet ring, 21,2
4...Magnetic powder, 23, 23'...Magnetic pole body.

Claims (1)

[Claims] 1 A yoke that has a pair of cylindrical magnetic pole parts with a non-magnetic blocking ring located in the center in between and abutting their tips. separated,
and a rotating body that forms a gap for enclosing magnetic powder between the outer periphery of the cylindrical part and the magnetic pole part, and is mechanically connected to a rotating shaft such as a braked shaft or an input/output rotating shaft in the disc-shaped part. , and magnetic powder is fixed to each bracket located on the left and right sides of the disc-shaped portion of the rotating body and supporting the yoke, and between each outer circumferential surface and the inner circumferential surface of the cylindrical portion of the rotating body. A magnetic coupling device comprising a pair of magnetic pole bodies constituting an enclosing gap, and generating a magnetic coupling force on both the inner and outer circumferential surfaces of a cylindrical portion of a rotating body, or selectively only on the outer circumferential surface.