Title of Invention

STATOR OF MAGNET-TYPE ROTATIONAL ELECTRICAL MACHINE AND PRODUCTION METHOD THEREOF

Abstract

(57) Abstract The present invention relates to a stator of a magnet-type rotational electrical machine that has main poles famed of permanent magnetic material, and auxiliary magnetic poles famed of soft steel material, which are adjacent to each other in the circumference direction and are fixed on an inner circumference of a cylindrical yoke, characterized in that said auxiliary magnetic poles are fixed to said yoke by welding projections provided on connection surfaces of said auxiliary magnetic poles and a method of manufacturing the stator of a magnet-type rotational electrical machine. PRICE: THIRTY RUPEES

Full Text

The present invention relates to a stator of a magnet-type rotational electrical machine, and more particularly, relates to a fixing method for auxiliary magnetic poles. DESCRIPTION OF THE RELATED ART Figure 8 is a conceptual diagram showing a known welding method for auxiliary magnetic poles of a stator of a magnet-type rotational electrical machine that is disclosed, for example, in Japanese Utility Model No. Sho 59-56975. In addition. Figure 9 is a cross-sectional view taken on line IX-IX of Figure 8. In this figure, a stator 8 comprises main poles 4 made of permanent magnetic material, and auxiliary magnetic poles 9 made of soft steel members, which are fixed on an inner circumference of a hollow cylindrical yoke 2. The auxiliary magnetic poles 9 are formed on thin plate portions 9b, which are rib-shaped, and whose thicknesses are thin in the radial direction. In addition, contact surfaces 9a of the auxiliary magnetic poles 9 are made to contact to the inner circumference 2a of the yoke 2. Therefore, by applying a voltage between an electrode 7a electrically connected to the thin plate portion 9b and an electrode 6a electrically connected to the outer circumference of the yoke 2 where the thin plate portion 9b is located, the thin plate portion 9b is welded and fixed to the yoke 2. In the known stator of the magnet-type rotational electrical machine that is constructed as above-described, the connection surfaces 9a of the auxiliary magnetic poles 9 fully contacts to the inner circumference surface 2a of the yoke 2. Therefore, the area of the welded surface connecting both surfaces by welding is large. Thus, since the concentrated current does not flow at the time of voltage application between the electrodes 6a and 7a, melting of the welded surfaces is sometimes not complete, and hence welding is not secure. Therefore, since fixing is not secure, this method has an issue that quality is not stable. SUMMARY OF THE INVENTION The present invention is intended to solve the above-described issue, and the object of the present invention is to obtain a stator of a magnet-type rotational t electrical machine that can be securely welded and controlled in stable quality. The present invention is characterized in a stator of a magnet-type rotational electrical machine that comprises main poles 4 made of permanent magnetic material, and auxiliary magnetic poles 9 made of soft steel material, which are adjacent to each other in the circumference direction and are fixed on the inner circumference of a cylindrical yoke 2, the auxiliary magnetic poles being fixed and welded with projections 19b provided on the connection surfaces 19a of the auxiliary magnetic poles. Accordingly the present invention provides a stator of a magnet-type rotational electrical machine that has main poles formed of permanent magnetic material, and auxiliary magnetic poles formed of soft steel material, which are adjacent to each other in the circumference direction and are fixed on an inner circumference of a cylindrical yoke, characterized in that said auxiliary magnetic poles are fixed to said yoke by welding projections provided on connection surfaces of said auxiliary magnetic poles. The present invention also provides a method of manufacturing a stator of a magnet-type rotational electrical machine as herein above described comprising the steps of preparing at least one welding projection on a connection surface of said auxiliary magnetic poles; placing said welding projection of said supporting magnetic pole into contact with an inner circumference of a cylindrical yoke; and causing an electrical current to flow through said welding projection in contact with said yoke. The invention will now be described more in detail with reference to the accompanying drawings, in which; Figure 1 is a front view showing a supporting magnetic pole of a stator of a magnet-type rotational electrical machine according to the present invention; Figure 2 is a conceptual view showing a welding method for a supporting magnetic pole; Figure 3 is a cross-sectional view taken on line Ill-Ill of Figure 2; Figure 4 is a front view showing a welding state of a supporting magnetic pole; Figure 5 is a side view showing a welding state of the supporting magnetic pole; Figure 6 is a cross-sectional view taken on line VI-VI of Figure 4; Figure 7 is a front view showing another shape of a supporting magnetic pole; Figure 8 is a conceptual diagram showing a known welding method for auxiliary magnetic poles of a stator of a magnet-type rotational electrical machine; and Figure 9 is a cross-sectional view taken on line IX-IX of Figure 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 is a front view showing a supporting magnetic pole of a stator of a magnet-type rotational electrical machine according to the present invention. Figure 2 is a conceptual view showing a welding method for a supporting magnetic pole, and Figure 3 is a cross-sectional view taken on line Ill-Ill of Figure 2. Figures 4 and 5 are a front view and a side view showing a welding state of a supporting magnetic pole, and Figure 6 is a cross-sectional view taken on line VI-VI of Figure 4. In addition, Figure 7 is a front view showing another shape of a supporting magnetic pole. The same parts or corresponding parts as those of the known stator of the magnet-type rotational electrical machine that are shown in Figures 8 and 9 are marked the same numerals, and description on them are omitted. In Figure 1, at both ends of the connection surface 19a of a supporting magnetic pole 19, projections 19b are formed respectively. The supporting magnetic pole 19 is produced by blanking a steel plate with a press and the like. Here, a conceptual welding method for the auxiliary magnetic poles 19 will be described with reference to Figures 2 and 3. First, a supporting magnetic pole 19 is located so that the projections 19b may contact to predetermined positions of the inner circumference of a cylindrical yoke 2. Then, in the state of pressing the auxiliary magnetic poles 19 to the inner circumference of the yoke 2, a voltage is applied between an electrode 7 electrically connected to the supporting magnetic pole 19 and an electrode 6 electrically connected to the outer circumference of the yoke 2 where the auxiliary magnetic poles 19 are disposed. In this time, since the current passed between the electrodes 6 and 7 concentrates upon the projections 19b, the projections 19b are melted so that the supporting magnetic pole 19 is welded to the yoke 2. When the connection surface 19a is made to contact to the yoke 2, a gap occurs between the connection surface 19a and the yoke 2 due to the projections 19b. However, since the projections are rpelted in welding, the connection surface 19a closely contacts to the inner circumference of the yoke 2 to get rid of the gap. Next, a concrete welding method in case of actually welding the auxiliary magnetic poles 19 will be described with reference to Figures 4, 5, and 6. An electrically insulating cylindrical base 36 having a flange-shaped leg in the lower edge is fixed to a supporting table and the like (not shown). The base 36 has an axial notch 36a at a portion of its cylindrical surface, for slidably receiving therein a wedge 37 which is arranged such that where the wedge 37 is moved to the right direction In Figure 6, its outer side surface is raised from a side surface of the base 36. On the outer circumference of the base 36, the hollow cylindrical yoke 2, auxiliary magnetic poles 19 disposed at regular intervals on the inner circumference of the yoke 2, electrically conductive guides 34 having U-shaped cross-sections and covering the auxiliary magnetic poles 19, electrically insulating spacers 35 inserted between the guide 34 and the adjacent guide 34 for positioning are disposed so that they can rotate in one body about the cylindrical base 36. Since the stator in this example is used for a six-pole type of magnet-type rotational electrical machine, six auxiliary magnetic poles 19 are disposed at 60' pitches. A welding process is performed after first positioning one of the auxiliary magnetic poles 19 to a position of a wedge 37. An arm 38 disposed on the base 36 is moved to the side of the yoke 2, and an end 38a of the arm 38 is pressed against the yoke 2 to establish an electrical contact therebetween. The other end 38b of the arm 38 presses the wedge 37 in the right direction in Figure 6 through a spring 39 and an electrode 31 a,and the wedge 37 is axially depressed with a constant force by the action of the spring 39. As the wedge 37 slides with in the slot 36a, Its side surface pushes the supporting magnetic pole 19 against the yoke 2 through the guide 34. In that state, by using the electrode 31a connected to the wedge 37 and the electrode 31b connected to the yoke 2, an electric current is passed through the supporting magnetic pole 19 and the yoke 2. The current flows in the order of the electrode 31a, wedge 37, guide 34, supporting magnetic pole 19, projection 19b, yoke 2, and electrode 31 b. By means of this, the projection 19b is melted, and hence the supporting magnetic pole 19 is welded to the yoke 2. In addition, the base 36, spacer 35 and arm 38 are made of insulating material members. After that, the yoke 2, guide 34, and spacer 35 are rotated at 60in one body, a next supporting magnetic pole 19 is positioned to a position of a wedge 37, and welding is performed in the same procfess as the above one. This process is repeated to weld six auxiliary magnetic poles 19 to the yoke 2. The stator of the magnet-type rotational electrical machine according to the present invention is similar to the known stator except a welding process. Figure 7 is a front view showing ahother shape of a supporting magnetic pole. The shape of the auxiliary magnetic poles 19 in Figure 7 is used for auxiliary magnetic poles 29 larger than the auxiliary magnetic poles 19 in Figure 1. Since it is necessary for -a connection surtace 29a to closely contact to the inner circumference of the yoke 2, projections 29b should be completely melted in welding. Therefore, each projection 29a does not become large as the supporting magnetic pole 29 becomes large. Accordingly, the four small projections are disposed respectively at four corners of the connection surface 29a. The auxiliary magnetic poles 29 are produced by moulding. In addition, the welding method for the auxiliary magnetic poles 29 is the same as that for the auxiliary magnetic poles 19. In the stator of the magnet-type rotational electrical machine constructed as described above, the current concentrates upon the projections 19b or 29b, and melts the projections 19b or 29b to weld the auxiliary magnetic poles 19 or 29 to the yoke 2. Therefore, the stator of the magnet-type rotational electrical machine can be obtained, the stator securely being welded and controlled in stable quality. WE CLAIM: 1. A stator of a magnet-type rotational electrical machine that has main poles forned of pennanent magnetic material, and auxiliary magnetic poles formed of soft steel material, which are adjacent to each other in the circumference direction and are fixed on an inner circumference of a cylindrical yoke, characterized in that said auxiliary magnetic poles are fixed to said yoke by welding projections provided on connection surfaces of said auxiliary magnetic poles. 2. A method of manufacturing a stator of a magnet-type rotational electrical machine as claimed in claim 1, said method comprising the steps of preparing at least one welding projection on a connection surface of said auxiliary magnetic poles; placing said welding projection of said supporting magnetic pole into contact with an inner circumference of a cylindrical yoke; and causing an electrical current to flow through said welding projection in contact with said yoke. 3. A stator of a magnet-type rotational electrical machine substantially as herein described with reference to the accompanying drawings. 4. A method of manufacturing a stator of a magnet-type rotational electrical machine substantially as herein described with reference to the accompanying drawings.

Documents:

1102-mas-1995 abstract.jpg

1102-mas-1995 abstract.pdf

1102-mas-1995 claims.pdf

1102-mas-1995 correspondence _others.pdf

1102-mas-1995 correspondence _po.pdf

1102-mas-1995 description (complete).pdf

1102-mas-1995 drawings.pdf

1102-mas-1995 form -1.pdf

1102-mas-1995 form -26.pdf

1102-mas-1995 form -4.pdf

1102-mas-1995 form -9.pdf