JP2009273356A - Method for manufacturing stator housing of electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture the stator housing of an electric motor by an easy method. <P>SOLUTION: The stator housing 1 has a polar housing 2, formed of plastics and at least one magnet 3, and the polar housing 2 is manufactured through an injection molding process or a press process for manufacturing the stator housing of the electric motor, wherein plastics containing at least permeable plastics or permeable materials is used in part with respect to the polar housing 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a method for manufacturing a stator housing for an electric motor which is advantageously used in an auxiliary machine provided in an automobile, the stator housing comprising a magnetic pole housing made of plastic and at least one magnet. The present invention relates to a method for manufacturing a stator housing of an electric motor by manufacturing a magnetic pole housing by an injection molding method or a pressing method.

  Furthermore, the present invention advantageously provides a stator housing for an electric motor used in an auxiliary machine provided in an automobile, the stator housing having a magnetic pole housing made of plastic, and at least in the magnetic pole housing. The present invention relates to a type in which one magnet is accommodated.

  International Publication No. 2006/039341 pamphlet describes a stator housing of an electric motor. The stator housing includes a plastic magnetic pole housing. The plastic magnetic pole housing contains a return path forming ring and a magnet attached to the return path forming ring, and can be manufactured by an injection molding method. In this case, the return path forming ring and the magnet are inserted into the magnetic pole housing after the magnetic pole housing is completed. According to another configuration described in WO 2006/039341, a return forming ring including a magnet is embedded in the housing wall during the pole housing injection molding process.

International Publication No. 2006/039341 Pamphlet

  An object of the present invention is to easily manufacture a stator housing of an electric motor, and in this case, to ensure that components housed in the stator housing are firmly fixed to the wall at the same time.

  In order to solve this problem, in the method of the present invention, at least a part of a magnetically conductive plastic or a plastic containing a magnetically conductive material is used for the magnetic pole housing.

  Further, in order to solve the above-mentioned problems, in the first stator housing of the present invention, the plastic of the magnetic pole housing is at least partially magnetic or includes a magnetic material. .

  Further, in order to solve the above problems, in the second stator housing of the present invention, the magnet is made of a plastic-bonded injection moldable or pressable material.

  Furthermore, in an advantageous embodiment of the invention, the magnet is embedded in the material of the pole housing during the injection molding process for the manufacture of the pole housing.

  Furthermore, in an advantageous embodiment of the invention, conductive metal particles are included in the plastic.

  Furthermore, in an advantageous embodiment of the invention, the magnetic pole housing has an expansion coefficient that at least approximately corresponds to the expansion coefficient of the magnet by the addition of a magnetically conductive material.

  Furthermore, in an advantageous embodiment of the invention, at least one magnet is magnetized only after being embedded in the pole housing.

  Furthermore, in an advantageous embodiment of the invention, the magnet is formed as an annular magnet, which is embedded in the plastic of the magnetic pole housing.

  Furthermore, in an advantageous embodiment of the invention, the magnet is formed as a magnet segment, which is embedded in the plastic of the pole housing.

  Furthermore, in an advantageous embodiment of the invention, at least one magnetic flux guiding element arranged corresponding to the magnet is embedded in the wall of the pole housing in the course of the injection molding or pressing process.

  Furthermore, in an advantageous embodiment of the invention, at least one bearing point for the armature shaft is formed on the wall of the pole housing in the course of the injection molding or pressing process.

  Furthermore, in an advantageous embodiment of the invention, the magnetically conductive material is only partially mixed into the plastic of the pole housing.

  Furthermore, in an advantageous embodiment of the invention, the section of the pole element containing the magnetic conducting material has a higher wall thickness than the section containing no magnetic conducting material.

  Furthermore, in an advantageous embodiment of the invention, the magnet is made of a plastic-bonded pressable or injection-mouldable material and is fixed to the inner wall of the pole housing by pressing or injection molding.

  Furthermore, in an advantageous embodiment of the invention, the magnet is produced by a sintering process, the sintering process is carried out directly in the pole housing, and the magnet is pressed against the inner wall of the pole housing during sintering, To join.

  An electric motor with a stator housing produced by one of the methods according to the invention is preferably used for auxiliary equipment provided in an automobile, for example a window lifter motor, wiper motor, seat adjustment motor or starter motor Also used as

  According to a first aspect of the invention, a method is provided for the manufacture of a stator housing for an electric motor. In this case, the stator housing has a magnetic pole housing made of plastic and at least one magnet. The pole housing is manufactured by injection molding and the magnet is coupled to the wall of the pole housing. This takes place in an advantageous configuration already during the injection molding process for the production of the pole housing.

  Furthermore, it has been proposed for the pole housing to use at least partially magnetically conductive plastics or plastics containing magnetically conductive materials. The magnetically conductive material serves to guide the magnetic flux starting from the magnet in the desired direction. Thereby, it is basically possible to omit the magnetic flux elements formed as separate components. Nevertheless, it is possible to use such a flux element when using a magnetically conductive material for the plastic pole housing.

  If one or more magnets are already embedded in the pole housing wall during the pole housing injection molding process, additional securing means for the one or more magnets can be omitted. Thereby, structural simplification is achieved. Furthermore, the manufacturing process is speeded up and simplified. This is because the manufacture of the magnetic pole housing and the embedding of the magnet in the wall of the magnetic pole housing can be carried out in one common work step. A further advantage is achieved, in part, between the pole housing and the abutment surface of the magnet and, on the other hand, a smaller spacing and coaxiality error between the magnet and the rotating armature. It is to be done. This reduces the air gap in the magnetic action circuit and improves the overall efficiency of the electric motor. Furthermore, this configuration can also reduce the overall weight of the stator.

  The addition of a magnetically conductive material to the pole housing material can produce an expansion coefficient that is approximately the same as the expansion coefficient of the magnet. This has the advantage that internal stresses do not actually occur, both during temperature changes and during shrinkage and expansion in conjunction with this temperature change. This is because the pole housing and the magnet are exposed to the same expansion, and thus there is no or little difference in expansion.

  According to an advantageous configuration, the plastic pole housing contains only a part or part of a magnetically conductive material, and thus the plastic pole housing has another region or section that is non-magnetic. It has been proposed that The magnetic section is in particular in direct contact with the magnet in order to allow the best possible return path. On the other hand, according to another configuration, it has been proposed that the entire magnetic pole housing is made of a magnetically conductive material, or that the magnetically conductive material is mixed in the plastic of the housing.

  As the magnetic conductive material, for example, metal particles are considered. The metal particles are mixed in the plastic and thus already contained in the plastic during the injection molding process.

  According to another advantageous configuration, a permanent magnet made of, for example, ferrite or NdFeB is used. In some cases, these magnets may be inserted into the pole housing first without being magnetized. The magnetizing process is then carried out, ie after joining or embedding permanent magnets in the wall of the pole housing.

  If the magnet is embedded in the inner wall of the pole housing, it is basically sufficient if only the face directed to the inner wall, and possibly also the end face, partially penetrates the plastic material of the pole housing. However, it is basically also possible to at least partly provide a plastic cover made of the material of the pole housing on the surface of the magnet that is opposite the inner wall.

  The magnets may be formed as individual magnet segments or may be formed as closed magnet rings.

  In accordance with another aspect of the present invention, a method for manufacturing a stator housing for an electric motor is provided. In this case, the stator housing has a magnetic pole housing made of plastic and at least one magnet, the magnet being made of a plastic-bonded injection moldable material, which material is the inner wall of the magnetic pole housing. Fixed by injection molding. In this configuration, the production steps of the magnetic pole housing and the manufacture or attachment of the magnet are basically carried out separately from each other. The pole housing, preferably made of plastic, is preferably manufactured in the first working step. Then, in a second working step, a magnet made of an injection moldable material is secured to the inner wall of the pole housing by injection molding. During this process, the lines of magnetic force can be pre-directed in the case of a plastic-bonded magnet (plastic magnet) already in the injection mold. Thereby, a higher magnetic field strength is achieved. The lines of magnetic force can be guided to the coil within the magnet itself or to a magnetic return path forming member in contact with the magnet. The magnetic field lines are returned from the return path forming member to the magnet and guided to the coil.

  A rigid joint can likewise be achieved through the fixing of the magnet by injection molding to the inner wall of the pole housing, thereby eliminating additional fixing means for fixing the position of the magnet to the pole housing. be able to. In addition, errors and air gaps are reduced, which improves overall efficiency.

  As material for the pole housing, plastic is preferably used. The manufacture of the magnetic pole housing is preferably carried out by pressing or injection molding. In the magnetic pole housing material, in some cases, a magnetically conductive material may be mixed so that the magnetic field lines are guided directly through the wall of the magnetic pole housing to form a magnetic return path. The However, it is also possible to use a plastic that does not contain a magnetically conductive material. In this case, in this case, the magnetic return path is guided directly via the magnet itself or via a return path forming member formed as a separate component. This return forming member is similarly inserted into the magnetic pole housing.

  In some cases, the pole housing is also made of a material different from plastic, such as a metallic material.

  According to another aspect of the present invention, there is provided a stator housing for an electric motor having a pole housing and at least one magnet, wherein the magnet is manufactured by a sintering process. A method is provided. The sintering process is performed directly in the pole housing. In this case, during sintering, the magnet is pressed toward the inner wall of the pole housing and coupled to the inner wall.

  This arrangement also has the advantage of a reduced air gap between the armature and the magnet, which achieves a smaller coaxiality error and, consequently, a higher efficiency. Furthermore, the fixing means for fixing the position of the magnet to the inner wall of the magnetic pole housing can be omitted. Furthermore, heat extraction is improved based on the lack of an air gap between the magnet and the housing. Since the manufacturing process of the magnet is combined with the fixing of the position of the magnet to the inner surface of the magnetic pole wall, the assembly work is also reduced.

  The magnet manufactured by the sintering method and directly attached to the inner wall of the magnetic pole housing may be formed in a circular shape or a segment shape.

  The plastic housing may be made of plastic as in the configuration described above, and is manufactured in particular by a plastic injection molding method. In this case, in some cases, a magnetic conductive material is mixed in the plastic material. However, this is not always necessary. However, it is also possible to construct a magnetic pole housing made of a material different from plastic, for example, metal.

  Magnetization is achieved with a suitable magnetizing tool after sintering of the permanent magnet.

  Further advantages and advantageous configurations can be taken from the further claims, the description of the drawings and the drawings.

It is a longitudinal cross-sectional view of the stator housing | casing of an electric motor provided with the plastic magnetic pole housing and the magnet embedded by injection molding on the wall of this magnetic pole housing. FIG. 2 is a cross-sectional view with respect to the longitudinal axis of the stator housing of FIG. 1. It is a figure which shows another Example of the stator housing in which the magnet is cyclically | annularly formed in the inner surface of the magnetic pole housing. A separate magnetic pole housing containing a magnetically conductive plastic and a magnet disposed on the inner surface of the magnetic pole housing and made of an injection moldable material and secured to the inner wall of the pole housing by injection molding. It is a figure which shows the stator housing of. It is a longitudinal cross-sectional view of the stator housing of FIG. It is a figure which shows another Example of the stator housing provided with the magnet formed in the circular shape fixed to the inner surface by injection molding. It is a longitudinal cross-sectional view of the stator housing of FIG. It is a figure which shows another stator housing of an electric motor provided with the magnetic pole housing and the segment-shaped magnet manufactured inside the magnetic pole housing by a sintering method. It is a longitudinal cross-sectional view of the stator housing of FIG. FIG. 9 is a view corresponding to FIG. 8 including the tools necessary for the sintering process. FIG. 10 is a view corresponding to FIG. 9 including the tools necessary for the sintering process.

  In the drawings, the same components are denoted by the same reference numerals.

  In the following, embodiments for carrying out the invention will be described in detail with reference to the drawings.

  1 and 2 show a stator housing 1 used for an electric motor. The stator housing 1 includes a plastic magnetic pole housing 2, and the material of the plastic magnetic pole housing 2 is made of plastic containing integrated magnetically conductive particles, for example, metal particles. Thereby, the magnetic pole housing 2 becomes magnetically conductive as a whole.

  A permanent magnet 3 is embedded in the inner wall of the magnetic pole housing 2. The permanent magnet 3 protrudes into the wall of the magnetic pole housing 2, and is thereby housed and fixed in position on the wall of the magnetic pole housing 2. The segmented permanent magnet 3 is completely incorporated into the wall of the magnetic pole housing 2, so that the inner surface of the magnet 3 is flush with the inner wall of the magnetic pole housing 2, that is, the same plane is formed. It's over. The embedding of the permanent magnet 3 in the wall of the pole housing 2 is preferably already carried out during the injection molding process for the manufacture of the pole housing 2, so that the manufacture of the pole housing 2 and the wall of the pole housing 2 are performed. The incorporation of the permanent magnet 3 is integrated into one common work step.

  The magnetically conductive particles, which are formed in particular as metal particles, are preferably distributed uniformly over the entire wall of the pole housing 2. Thereby, the guidance of the magnetic flux starting from the magnet 3 on the wall of the magnetic pole housing 2 is achieved. In the area of the permanent magnet 3, the wall of the magnetic pole housing 2 has a larger thickness than the outside of the permanent magnet 3.

  The material of the magnetic pole housing 2 is made of a relatively hard plastic. This plastic makes it possible to form the bearing points 5 in the region of the end face of the pole housing 2. In some cases, additional bearing members are incorporated into the wall of the pole housing 2. The motor axis is indicated by 6. On the side of the end face opposite to the bearing location 5, the magnetic pole housing 2 is provided with a fixed section 4 formed integrally. Via this fixing section 4, the magnetic pole housing 2 can be fixed, for example, to the transmission device housing.

  As can be seen from FIG. 2, a plurality of ribs 7 are integrally formed on the outer surface of the magnetic pole housing 2 by injection molding.

  Although the embodiment according to FIG. 3 substantially corresponds to the embodiment according to FIG. 1 or FIG. 2, in the embodiment according to FIG. 1 or FIG. The third embodiment has a difference that the permanent magnet 3 is formed in a circular shape. The magnetic field lines starting from the magnet 3 are guided circumferentially directly in the material of the magnet 3, which essentially eliminates the need for an additional return-forming element and, in some cases, conducts magnetism into the material of the pole housing 2. Mixing of these materials can also be omitted.

  In the embodiment according to FIGS. 4 and 5, the stator housing 1 has a magnetic pole housing 2 made of plastic containing a magnetically conductive material. A permanent magnet 3 is fixed to the inner wall of the magnetic pole housing 2 by injection molding of the material. For this purpose, the permanent magnet 3 is made of a plastic-bonded injection moldable material, and after completion of the pole housing 2, a permanent working material is injected into the inner wall of the pole housing 2 in a separate work step. It is fixed. This has the advantage that a direct coupling is achieved between the permanent magnet 3 and the pole housing 2 without the need for providing additional fixing means for the permanent magnet 3. The permanent magnet 3 is not incorporated in the wall of the magnetic pole housing 2 but is simply located on the inner surface of the wall. In this case, the coupling is achieved by a process of injection molding the material of the permanent magnet 3 onto the inner wall of the pole housing 2.

  6 and 7 also, the magnet 3 is fixed to the inner wall of the magnetic pole housing 2 by injection molding. The permanent magnet 3 is formed in a circular shape. The magnetic pole housing 2 is made of plastic and is similarly manufactured by an injection molding method. Magnetic material particles may be mixed in the material of the magnetic pole housing 2. However, in some cases, a conductive material is omitted. This is because, based on the circular shape of the permanent magnet 3, a direct return path of the magnetic flux through the magnet 3 itself is achieved.

  8 and 9, the permanent magnet 3 is manufactured by a sintering method. This permanent magnet 3 is located directly on the inner surface of the magnetic pole housing 2 and is held there without additional fixing means. The pole housing 2 is preferably made of plastic as in the previous embodiment. In the material of the magnetic pole housing 2, in some cases, magnetically conductive particles may be mixed.

  The permanent magnet 3 is manufactured inside the magnetic pole housing 2 by a sintering method. For the sake of clarity, FIGS. 10 and 11 show a sintering tool consisting of a core punch 8, a press punch 9 and a counter holder 10. The core punch 8 is inserted into the inner chamber of the magnetic pole housing 2. In this case, a segment-shaped annular chamber for the permanent magnet 3 is left between the outer peripheral surface of the core punch 8 and the inner wall of the magnetic pole housing 2. This segmented chamber is filled with the sintered material of the permanent magnet 3. The press punch 9 is then pressed axially against the sintered material for compression. The counter holder 10 is in contact with the outer surface of the magnetic pole housing 2.

  DESCRIPTION OF SYMBOLS 1 Stator housing, 2 Magnetic pole housing, 3 Permanent magnet, 4 Fixed division, 5 Support location, 6 Motor axis, 7 Rib, 8 Core punch, 9 Press punch, 10 Counter holder

Claims (15)

  A method for producing a stator housing of an electric motor for use in an accessory provided in an automobile, preferably comprising a magnetic pole housing (2) made of plastic and at least one magnet. (3) and manufacturing the magnetic pole housing (2) by an injection molding method or a pressing method to manufacture a stator housing of an electric motor. A method for manufacturing a stator housing, characterized in that it uses a partially conductive plastic or a plastic containing a conductive material.   The method according to claim 1, wherein the magnet (3) is embedded in the material of the pole housing (2) during an injection molding process for the manufacture of the pole housing (2).   The method according to claim 1 or 2, wherein the conductive metal particles are contained in a plastic.   4. The method according to claim 1, wherein the magnetic pole housing has a coefficient of expansion approximately corresponding to that of at least the magnet. .   5. The method according to claim 1, wherein the at least one magnet is magnetized only after being embedded in the pole housing.   6. The method as claimed in claim 1, wherein the magnet (3) is formed as an annular magnet and the annular magnet is embedded in the plastic of the magnetic pole housing (2).   A method according to any one of the preceding claims, wherein the magnet (3) is formed as a magnet segment and the magnet segment is embedded in the plastic of the pole housing (2).   The at least one magnetic flux guiding element arranged corresponding to the magnet (3) is embedded in the wall of the magnetic pole housing (2) in the course of an injection molding or pressing process. Method.   9. A method as claimed in claim 1, wherein at least one bearing point (5) for the armature shaft is formed in the wall of the pole housing (2) in the course of an injection molding or pressing process. .   10. The method according to claim 1, wherein the magnetically conductive material is only partially mixed into the plastic of the pole housing (2).   11. A method according to claim 10, wherein the section of the pole element (2) containing the magnetically conductive material has a higher wall thickness than the section containing no magnetically conductive material.   12. The method according to claim 1, wherein the magnet (3) is made of a plastic-bonded pressable or injection-moldable material and is fixed to the inner wall of the pole housing (2) by pressing or injection molding.   The magnet (3) is manufactured by a sintering method, the sintering process is carried out directly in the pole housing (2), and the magnet (3) is pressed against the inner wall of the pole housing (2) during sintering. The method according to claim 1, wherein the method is coupled to an inner wall.   A stator housing for an electric motor used for an auxiliary machine provided in an automobile is advantageous, and the stator housing has a magnetic pole housing (2) made of plastic. In the type in which at least one magnet (3) is accommodated, the plastic of the pole housing (2) is at least partly magnetic or a magnetic material is contained in the plastic. A stator housing for an electric motor.   Preferably, in the stator housing of an electric motor used for an auxiliary machine provided in an automobile, the stator housing has a magnetic pole housing (2) made of plastic, and at least one in the magnetic pole housing (2). A stator housing for an electric motor, characterized in that, in the form of accommodating two magnets (3), the magnet (3) is made of a plastic-bonded injection-moldable or pressable material.

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