GB2039158A - An eddy current coupling - Google Patents

Abstract

The ferromagnetic output member 60 of an eddy current coupling is disposed axially between two spaced toothed input members mechanically connected to a flywheel 13 mounted on the input shaft 10. The speed of the output member is controlled by varying the current in winding 15 in response to the output of a tachogenerator 90. The apparatus is suitable for use in a sewing machine. <IMAGE>

Description

SPECIFICATION An electricmagnetic driving mechanism As far as the convention driving mechanism of clutch type is concerned, the transmission force rests solely on the lining plate on the clutch member, grasping its coupling means by the friction force existing on both contacting surfaces thereof. This coupling means transfer the exerted torque to the transmission shaft and then further to the utilization device.

This mechanism of clutch type, which involves friction, can easily allow the deterioration of the machine components, especially during partial contact. Therefor, it results in frequent replacements of deteriorated parts which are not economical and efficient.

Summary of this Invention It is the object of this invention to overcome the disvantages found in the conventional driving mechanism of clutch type and to provide a frictionless electricmagnetic driving mechanism which employs the eddy current created by a revolving magnetic field to revolve an annular magnetic conductive member, thereby driving the transmission shaft.

Another object of this invention is to provide an electricmagnetic driving mechanism which is compact in construction and economical in manufactruing.

Still another object of this invention is to provide an electricmagnetic driving mechanism which is smooth in operation and durable in use.

This invention will be more fully understood from the description of the preferred embodiments with the following accompanying drawings.

Brief Description of the Drawings Figure 1 is an exploded view of a preferred embodiment of a revolving assembly and a flywheel core according to this invention wherein the upper magnetic conductive disc is partly taken away; Figure 2 is an oblique projection of a preferred embodiment of a revolving assembly according to this invention, wherein the revolving assembly in semi-assembled position beneath the upper magnetic conductive disc is partly taken away; Figure 3 is a fragmentary axial sectional view of a preferred embodiment according to this invention.

As shown in Fig. 3, the motor shaft 10 is held within the bearing 1 2 of the motor housing 11 and the flywheel core 1 3 is axially mounted on the motor shaft 1 0. Provided with two sets of induction winding 15-15 therein the iron core 14 is secured to the motor housing 11 the outer diameter of said iron core 14 being larger than that of said flywheel core 3. As shown in Fig. 1, the inner magnetic conductive disc 20 comprises a ring 22 with threaded holes on its periphery and eight sets of outward extensive magnetic conductive plates 21-21 with threaded holes 211-211 at their ends, each of the latter being generally in L shape. It will be understood that eight sets of outward extensive magnetic conductive plates 21-21 are horizontally secured to the ring 22 in a way that they are spaced in equal distance.The outer magnetic conductive member 30 has an outer diameter larger than that of said iron core 14 and is horizontally provided with eight sets of inward extensive magnetic conductive plates 31-31 upon one side thereof, said inward extensive magnetic conductive plates 31-31 being spaced likewise in equal distance. In assembling, the outward extensive magnetic conductive plates 21-21 are respectively positioned between the inward extensive magnetic conductive plates 31-31. And, also as shown in Fig. 1, an insulating ring 40 is inserted into the outer conductive member 30 from the free end thereof until it is stopped by the inward extensive magnetic conductive plates 31-31.On the heels of the insulating ring 40, the flywheel core 1 3 is received within the outward magnetic conductive member 30, wherein the flywheel core 1 3 is fixedly secured on to the ring 22 by means of the screws (not shown in the drawing) through the threaded holes of both parts.

As shown in Fig. 2, with the provision of a hub 54, the upper magnetic conductive disc 50 is further provided with two different kinds of segregated protrusive plates on its back surface: eight ones with flat surface are referred to as first protursive magnetic conductive plates 53-53, while the other eight ones each with a pair of flanges 51-51 at the end thereof are referred to as second protrusive magnetic conductive plates 52-52. And between each pair of flanges 51-51, a threaded hole 511 is still further provided. Attention should be drawn to the feature that the outer diameter of the upper magnetic conductive disc 50 is generally the same as the outer diameter constituted by the outward extensive magnetic conductive plates 21-21 of the inner magnetic conductive disc 20.In assembling, firstly the upper magnetic conductive disc 50 is placed upon the inner magnetic conductive disc 20 whereby eight pairs of flanges 51-51 respectively stand rightly upon the edges of eight outward extensive magnetic conductive plates 21-21 and eight first protrusive magnetic conductive plates 53-53 lie respectively rightly upon eight inward extensive magnetic conductive plates 31-31; Secondly eight fixing members are employed to insert through the threaded holes 511-511 and the threaded holes 211-211 so as to secure the upper magnetic conductive disc 50 and the inner magnetic conductive disc 20 together.It will then be understood that the inner magnetic conductive disc 20 is secured on to the flywheel core 13; the inner magnetic conductive disc 20, the outer magnetic conductive member 30 and upper magnetic conductive disc 50 are securedly assembled together; and the iron core 14 is disposed spacedly between the flywheel core 1 3 and the periphery of the hollow column 32 of the outer magnetic conductive disc 30. Thus, when the flywheel core 1 3 is driven by the motor shaft 10, the inner magnetic conductive disc 20, the outer magnetic conductive member 30 and upper magnetic conductive disc 30 will revolve coaxially thereby.

The foregoing members inclusively of the inner magnetic conductive disc 20, the outer magnetic conductive member 30 and upper magnetic conductive disc 50 are the main parts of the revolving assembly. As shown in Fig. 3, an annular magnetic conductive member 60 is disposed within said revolving assembly, i,e; on the one side of said annular magnetic conductive member 60 are the outward extensive magnetic conductive plates 21-21 and inward extensive magnetic conductive plates 31-31, while on the other side thereof are the first protrusive magnetic conductive plates 52-52 and second protrusive magnetic conductive plates 53-53. The magnetic conductive revolving member 60 is fastened on to the supporting flange 61 which is, as indicated in Fig. 3, mounted fixedly upon the transmission shaft 70.Thus, the annular magnetic conductive member 60 when driven to revolve will drive the transmission shaft 70 to move revolvingly. The transmission shaft 70 is provided within the bearing 1 7 of the outer housing 16, the bearing 54 of the upper magnetic conductive disc 50 and the bearing 18 of the flywheel core 1 3.

Accordingly, the transmission shaft 70 may carry, for example, a pulley (which is not shown), and the pulley may be connected over a V-belt to a utilization device, such as the main shaft of a sewing machine.

When two sets of induction winding 15-15 are energised, a magnetic force flow or path is created as indicated in the drawing by the dotted line 80 which encircles two sets of induction winding 1 5-1 5, passing through the iron core 14, over the hollow column portion 32 of the outer magnetic conductive member 30 and the inward extensive magnetic conductive plates 31-31, and from there over the annular magnetic conductive member 60, over the second protrusive magnetic conductive plates 53-53 and first protrusive magnetic conductive plates 52-52 of the upper magnetic conductive disc 50, and returning over the annular magnetic conductive member 60, and over the outward extensive magnetic plates 21-21 and the ring 22 of the inner magnetic conductive disc 20 and from there through the flywheel core 13, back to the iron core 14.Meanwhile, a revolving magnetic field is also created during "energi- zation", for altogether the inner magnetic conductive disc 20, the outer magnetic conductive member 30 and upper magnetic conductive disc 50 are driven to revolve by the flywheel core 1 3. Now, due to the inductive action of the revolving magnetic field, there is an eddy current, induced on the annular magnetic conductive member 60 which revolves therein to drive the transmission shaft 70 to move revolvingly. The braking thereof can be obtained by means of an additional braking member and as may be found it is not described here detailedly.

As shown in Fig. 3, a speed generator 90 is further secured on the transmission shaft 70 for detecting the speed of the revolution of the transmission shaft 70 itself and regulating its speed. The method of speed regulation employed here is to adjust the current of two sets of inductive winding 1 5-1 5 so as to change the power of the revolving magnetic field whereby the speed of the annular magnetic conductive member 60 and that of the transmission shaft 70 are under control.

The frictionless revolving motion according to this invention is very smooth and also can be controlled by simple operation. And, as can be understood from above, this invention has reduced the weights of all components and has increased the speed of reaction.

What has been foregone hereinabove is the preferred embodiment thereof, having the purpose of more expressly describing this invention. Attention should be drawn to the fact that, instead of two sets of inductive winding, one may use one set thereof. And the employed inner magnetic conductive disc, outer magnetic conductive member and upper magnetic conductive disc of similar type to those according to this invention by any person skilled in the art thereof should be considered as within the extent of this invention.

Claims (9)

1. An electricmagnetic driving mechanism comprising a flywheel core to be axially mounted to the motor shaft; a transmission shaft to be mounted to the utilization device; a revolving assembly including an inner magnetic conductive disc, an outer magnetic conductive member, and an upper magnetic conductive disc, said revolving being secured to said flywheel core; an annular magnetic conductive member to be secured to a supporting flange which is axially mounted on said transmission shaft, said annular magnetic conductive member being disposed in spaced relation between said upper magnetic conductive disc and the assembled inner magnetic conductive disc and outer magnetic conductive member; an insulating ring to be disposed between said flywheel core and said inner magnetic conductive disc; and an iron core with at least one set of induction winding therein to be secured on to the motor housing, said iron core being disposed in spaced coaxial relation between sdid flywheel core and the hollow column of said outer magnetic conductive member; having the features that when said induction winding is energised, it creates a magnetic force flow or path which encircles said induction winding, passing through said iron core, over the hollow column of said outer magnetic conductive member and the inner magndtje conductive disc, and from there over the annular magnetic conductive member, over said upper magnetic conductive disc, and returning reversely through said path, back to said iron core to form a revolving magnetic field so that an eddy current is created on said annular magnetic conductive member which revolves as a result to drive said transmission shaft.

2. An electricmagnetic driving mechanism as described in Claim 1, wherein said inner magnetic conductive disc is provided with a ring with threaded holes through the periphery thereof and a plurality of outward extensive magnetic conductive plates with threaded holes through the edges thereof, said outward extensive plates being horizontally secured on to the rim of said ring.

3. An electricmagnetic driving mechanism as described in claim 1, wherein said outer magnetic conductive member is a hollow column in configuration, at on end of which there is horizontally provided a plurality of inward magnetic conductive extensive plates.

4. An electrimagnetic driving mechanism as described as described in claim 1, wherein the outer diameter of said insulating ring is smaller than the inner diameter of said outer magnetic conductive member, while the inner diameter of said insulating ring is smaller than the outer diameter of said flywheel core.

5. An electricmagnetic driving mechanism as described in claim 1, wherein said upper magnetic conductive disc comprises in construction a hub and a disc body, upon one side of said disc body there being provided alternatively two sets of protrusive magnetic conductive plates, on set of which has the provision of pairs of flanges at the edges thereof, between each pair of said flanges there being provided a threaded hole.

6. An electricmagnetic driving mechanism as described in claims 1, 2, 3, 4, and 5, wherein said outward extensive magnetic conductive plates, said inward extensive magnetic conductive plates, either set of said protrusive magnetic conductive plates and pairs of flanges corrrespond to another in number.

7. An electricmagnetic driving mechanism as described in claims 1, 2, 3, 4 and 6, wherein, in assembling, said outward extensive magnetic conductive plates are alternately disposed between said inward extensive magnetic conductive plates and then, on the heels of the insertion of said insulating ring into said outer magnetic conductive member, said flywheel core is inserted therein and then a plurality of fixing members are employed through the threaded holes thereof to secure the ring of said inner magnetic conductive magnetic disc and said flywheel core together.

8. An electricmagnetic driving mechanism as described in claims 1, 2, 3, 4, 5, 6 and 7, wherein, in assembling, the set of protrusive magnetic conductive plates with flanges thereupon are disposed upon said outward extensive magnetic conductive plates and secured on thereto, by means of the fixing members through the threaded holes thereof, while the other set of protrusive magnetic conductive plates are disposed upon said inward extensive magnetic conductive plates.

9. An electricmagnetic driving mechanism substantially as herein described with reference to the accompanying drawings.