JPH039123A - Magnetic grain type electromagnetic coupler device - Google Patents

Abstract

PURPOSE:To prevent slip of a driven element due to over load by mounting an armature, which has the friction face opposite to the axial end face of a driver and adsorbs the driver corresponding to magnetic force of an exciting coil, on the driven element. CONSTITUTION:The rotation of a driver 3 is transfered to a driven shaft 8 by an armature which is made up with a plate 24 fixed to the driven shaft 8 and a friction plate 22 supported via a plate spring 23. The armature 21 is located on the axial end face of the driver 3. When the exciting coil 2 is electrified during the rotation of the driver 3, magnetic flux is produced and magnetic grains 11 are magnetized and joined with a driven element 10 in an axial direction to rotate the driven shaft 8. When the driven shaft 8 is given over load, the magnetic flux is formed into a dotted line (B) and the friction plate 22 is magnetically adsorbed to a drive member 5 to cause greatly increased torque and prevent the occurrence of slip.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coil stationary magnetic particle type electromagnetic coupling device.

[Conventional technology]

A conventional electromagnetic coupling device of this type was constructed as shown in FIG.

FIG. 2 is a sectional view showing a conventional magnetic particle type electromagnetic coupling device. In the figure, reference numeral 1 denotes a fixed frame made of a magnetic material. An excitation coil 2 is built into the fixed frame 1, and a flange 1a for attachment to a fixed part (not shown) is integrally provided. Reference numeral 3 denotes a driving body connected to a driving source (not shown), and this driving body 3 includes a pair of cylindrical driving members 4.5 on both sides made of a magnetic material arranged at a predetermined interval in the axial direction, and both of these cylindrical driving members 4.5. It is composed of a coupling ring 6 made of a non-magnetic material that integrally connects the side movement member 4.5, and its outer circumferential surface faces the inner circumferential surface of the fixed frame 1 with an air gap g interposed therebetween. It is rotatably supported by the fixed frame l via a pair of bearings 7 in this state. Reference numeral 8 denotes a driven wheel, and this driven shaft 8 is rotatably supported on the inner peripheral portion of the driving body 3 via a pair of bearings 9. Reference numeral 10 denotes a driven member for transmitting the rotation of the driving member 3 to the driven shaft 8. This driven member 10 is formed into a disk shape from a magnetic material, and its outer peripheral portion is connected between the driving members 4 and 5. facing into the gap and both sides 10a.

10b is fixed to the driven shaft 8 while facing the inner end surfaces 4a, 5a of the driving members 4, 5 through small air gaps g+, gt in the axial direction, respectively. 11
are magnetic particles filled in the air gap g + + g z. Reference numeral 12 denotes a sealing member for preventing the magnetic particles 11 from scattering, and this sealing member 12 is fixed to the inner peripheral part of the driving body 3, and the elastic seal part is in sliding contact with the outer peripheral surface of the driven shaft 8. It is configured to 13
14 is a retaining ring that is fitted onto the driven shaft 8 and restricts the axial movement of the bearing 9; and 14 is a retaining ring that is fitted onto the drive body 3 and restricts the axial movement of one of the bearings 7. . Note that Φ in the figure indicates magnetic flux.

Next, the operation of the conventional magnetic particle type electromagnetic coupling device configured as described above will be explained. When an exciting current is applied to the exciting coil 2 while the driving body 3 coupled to the driving source is being rotated, a magnetic flux Φ is generated as shown by the dotted line in the figure. Due to this magnetic flux Φ, the magnetic particles 11 in the air gaps g+ and gz are magnetized and connected in a chain shape in the axial direction, and the driven body 1
0 is rotated together with the driving body 3 or while sliding. This causes the driven shaft 8 to rotate. The torque is controlled by controlling the excitation current, and it can be used in a continuous sliding state within the allowable temperature rise range.

Note that even when the drive body 3 is rotated, the driven shaft 8 is normally connected to a load device (not shown) until excitation starts as described above.
is not driven by mechanical losses.

[Problem to be solved by the invention]

However, in the conventional magnetic particle type electromagnetic coupling device configured as described above, when the driving body 3 and the driven shaft 8 are connected by the magnetic particles 11 and rotated integrally, an excessive force is applied to the driven shaft 8. When a load is applied, torque becomes insufficient and slip occurs at the connecting portion between the driving body 3 and the driven body 10. If this slip state continues for a long time, there is a problem in that the magnetic particles 11 and the like are burned out.

Further, even if no special overload is applied, the magnetic particles 11 deteriorate due to long-term use, and the driving body 3 and driven body 10, which were completely connected, gradually start to slip.
It is easy to burn out in the same way as above.

[Means to solve the problem]

The magnetic particle type electromagnetic coupling device according to the present invention has an armature attached to the driven body, which has a friction surface facing the axial end face of the driving body, and is magnetically attracted to the driving body according to the magnetic force of the excitation coil. It is something.

[For production]

When the magnetic force of the excitation coil is increased and the driving body and driven body are rotated together, the armature is magnetically attracted to the driving body, and torque is also transmitted through this armature.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG.

FIG. 1 is a sectional view showing a magnetic particle type electromagnetic coupling device according to the present invention. In the same figure, the same or equivalent members as those explained in FIG. Omitted.

In FIG. 1, 21 is an armature for transmitting the rotation of the driving body 3 to the driven shaft 8. This armature 21 includes a friction plate 22 formed in a disc shape of a magnetic material, and a plate spring that connects this friction plate 22. 23, and a plate 24 fixed to the driven shaft 8, the friction plate 2
2 is disposed inside the fixed frame 1 at a position facing the axial end surface of the drive member 5 with an air gap h in the axial direction therebetween. In addition, 1. The outer diameter of the friction plate 22 is slightly larger than that of the drive member 5, and the distance (air gap) between the drive member 3 and the inner peripheral surface of the fixed frame 1 is larger than that of the drive member 5. It is set to be narrower than the interval. That is, when the excitation coil 2 is excited with a magnetic force greater than a predetermined value, a magnetic circuit is formed in which the magnetic flux passes from the drive member 5 through the friction plate 22 to the fixed frame 1, and the friction plate 22
is magnetically attracted to the drive member 5 against the elastic force of the leaf spring 23. In this embodiment, when the excitation coil 2 is excited so that the transmission torque becomes maximum, the friction plate 22
is set to be magnetically attracted to the drive member 5.

Further, the drive member 5 used in this embodiment is formed to have a reduced cross-sectional area by reducing its axial length, which increases magnetic resistance and makes it more likely to be magnetically saturated. It is possible to easily pass magnetic flux to the friction plate 22 side of 21. 25 is the armature 2
This cover 25 is a cover for preventing dust etc. from entering one part.The outer circumference of this cover 25 is fixed to one end of the fixed frame 1, and the inner circumference is connected to the driven shaft 8 via a bearing 26. has been done. That is, this cover 25 allows the fixed frame 1 to be
One end thereof is rotatably supported relative to the driven shaft 8. Note that 27 is a retaining ring that is fitted onto the driven shaft 8 and restricts movement of the bearing 26 in the axial direction.

Next, the operation of the magnetic particle type electromagnetic coupling device of the present invention will be explained. When the drive body 3 is rotated, the excitation coil 2
When an excitation current is applied to the magnet, a magnetic flux is generated as shown by the dotted line A in the figure. This magnetic flux magnetizes the magnetic particles 11 and connects them in a chain in the axial direction, causing the driven body 10 to rotate together with the driving body 3 or while sliding, thereby rotating the driven shaft 8.

When the excitation current is below a predetermined value, by controlling the current value, the powder clutch's unique characteristic of being able to be used while slipping can be obtained, and the transmitted torque can be controlled. When the current value exceeds a certain value, the magnetic resistance of the driving member 5 is large, and the magnetic saturation is almost reached.
The magnetic flux is passed from the drive member 5 to the fixed frame 1 via the friction plate 22 of the armature 21, as indicated by the dotted line B in the figure. At this time, the friction plate 22, which had been separated from the end surface of the drive member 5 through an air gap due to the elastic force of the plate spring 23, is moved to the drive member 5 by magnetic force against the elastic force of the plate spring 23. It will be magnetically attracted.

When the armature 21 is connected to the drive body 3, the torque transmitted by the magnetic particles 11 and the driven body 10 and the torque transmitted by the connection between the drive member 5 and the friction plate 22 are added, so the torque is significantly increased (half). lockup). Therefore, when the magnetic force of the excitation coil 2 is increased and the driving body 3 and the driven shaft 8 are rotated together, the friction plate 22 of the armature 21 is magnetically attracted to the driving body 3, and the friction plate 22 of the armature 21 is magnetically attracted to the driving body 3. However, torque will still be transmitted.

〔Effect of the invention〕

As explained above, the magnetic particle type electromagnetic coupling device according to the present invention has a friction surface facing the axial end surface of the drive body,
An armature that is magnetically attracted to the drive body according to the magnetic force of the excitation coil is attached to the driven body, so when the magnetic force of the excitation coil is increased and the drive body and driven body are rotated together, the armature It is magnetically attracted to the driving body, and torque is also transmitted through this armature. therefore,
When used in a fully connected state like a selective logging clutch, even if an overload is applied to the driven body, slippage due to insufficient torque is less likely to occur, thus reliably preventing magnetic particles from being burnt out. This has the effect of extending the maintenance and inspection period and the life of the device. In addition, even if the magnetic particles deteriorate and the coupling force between the magnetic particles and the driven object is reduced, the armature can still transmit torque, so it can be used for a long time without slipping. be.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a magnetic particle type electromagnetic coupling device according to the present invention, and FIG. 2 is a sectional view showing a conventional magnetic particle type electromagnetic coupling device. 1...Fixed frame, 2...Exciting coil, 3...
Drive body, 8... Driven shaft, 10... Driven body, 1
1... Magnetic particle, 21... Armature, 22
...Friction plate.

Claims (1)

[Claims] A driving body rotatably installed in a field containing an excitation coil, and a driven body rotatably installed along the same axis at the axial center of the driving body rub magnetic particles sealed between them. In a magnetic particle type electromagnetic coupling device connected as a medium, an armature that has a friction surface facing an axial end face of the driving body and is magnetically attracted to the driving body according to the magnetic force of an excitation coil is connected to the driven body. A magnetic particle type electromagnetic coupling device, characterized in that it is attached to a magnetic particle type electromagnetic coupling device.