WO2000076053A1

WO2000076053A1 - Electric motor

Info

Publication number: WO2000076053A1
Application number: PCT/FR2000/001599
Authority: WO
Inventors: Vincent Emmanuel Laurent Boitel; Frédéric Christian BONNEFOY; Eric Serge Fournier
Original assignee: Siemens Automotive Moteurs Electriques S.A.
Priority date: 1999-06-09
Filing date: 2000-06-09
Publication date: 2000-12-14
Also published as: FR2794910A1; FR2794910B1; AU6285200A

Abstract

The invention concerns an electric motor comprising a generally cylindrical stator and a rotor mounted rotatable in said stator between two bearings integral with the stator. The stator comprises an electrically insulating plastic part formed with an overmoulded component, said part comprising: 1) a first flange shaped to support one of the bearings of the rotor and 2) means configured to contribute to the support of the motor itself in the apparatus housing said motor. A second flange (55) incorporates: a) carbon housings (561, 562) for powering the motor, b) an electrical connector box (57) and c) a housing for an electronic module (58) for controlling the rotational speed of the motor.

Description

ELECTRIC MOTOR The present invention relates to an electric motor of the type comprising a) a generally cylindrical stator and b) a rotor rotatably mounted in said stator between two bearings integral with the stator There is shown in Figure 1 of the accompanying drawing a motor of this well-known type, with direct current supply for example, comprising a stator generally referenced 1 and a rotor generally referenced 2, mounted in rotation in bearings 3,4 integral with the stator.

The stator consists of a metal carcass 5ι, 5 generally cylindrical on the inner wall of which are fixed at least two permanent magnets 6ι, 6 ₂ by two or four staples such as 7ι, 7 _2l 7 ₃ , 7 ₄ for example, and / or by bonding. Each magnet takes the form of a curved tile like the carcass wall on which it is fixed, and the two magnets are placed opposite, inside the carcass, in the annular space separating the latter from the surface. rotor 2.

This conventionally comprises an electric winding 8 crossed by a shaft 9 supported at its ends by the bearings 3,4, themselves supported by flanges 10,11 respectively, each fixed on one of the two axial ends of the motor. There is also found in the motor a set of brushes 13 suitable for establishing electrical contact with a collector 14 connected to the winding 8 for the supply thereof, as is well known.

The flanges 10,11 can be produced by stamping, molding, etc., then assembled to the carcass 5ι, 5 ₂ , by crimping or other well-known fixing means. The need to provide forms or cutouts on the carcass necessary for mounting these flanges makes the manufacture of this carcass more difficult.

To support the engine in the device which receives it, for example a ventilation, heating, and / or air conditioning device of the passenger compartment of a motor vehicle, an annular disc such as 15 is used, pierced with holes 16ι, 16 _2> etc .. for the passage of bolts or screws for fixing the motor to this device, this disc being itself fixed to the carcass 5ι, 5 ₂₎ by crimping, welding, bonding, etc. or integrated into the one of the bearing support flanges 10.11.

The motor can thus be fixed in a molded plastic housing provided in the device with, possibly, the interposition of vibration dampers. It is understood that the assembly and mounting of a motor thus constituted calls for a large number of parts and assembly operations which obviously increase the costs of manufacturing the device equipped with this motor. This is particularly harmful when it is a mass-market device such as that mentioned above, forming part of the equipment of a motor vehicle, which must be manufactured at a contained cost to remain accessible to a large clientele.

The object of the present invention is therefore to produce an electric motor of the type described in the preamble to the present description, which is designed so as to reduce its manufacturing and mounting cost in the apparatus which accommodates it, by reducing the number of engine assembly and mounting operations.

The present invention also aims to achieve such an engine with increased manufacturing precision promoting the improvement of engine performance, with fewer parts and reducing the number of sources of vibration present in the engine. These objects of the invention are achieved, as well as others which will appear on reading the description which follows, with an electric motor of the type described in the preamble to the present description, remarkable in that the stator of this motor comprises an electrically insulating plastic part, formed in one piece by overmolding, said part comprising 1) a first shaped means for supporting one of the bearings of the rotor and 2) a second shaped means for participating in the support of the motor itself in a device accommodating said motor.

As will be seen below in detail, a part is thus formed, by a single overmolding operation, which fulfills several functions previously performed by several different parts, which makes it possible to lower the manufacturing cost price of the engine.

According to other characteristics of the motor according to the invention, the first support means takes the form of a flange protecting an axial end of said rotor The second support means takes the form of a flange extending radially from the stator and pierced with a circular distribution of holes for the passage of fastening members of the engine on the receiving device.

Other characteristics and advantages of the present invention will appear on reading the description which follows and on examining the appended drawing in which:

FIG. 1 is a view in axial section of an electric motor of the prior art, described in the preamble to this description, FIGS. 2 and 3 are perspective views and in axial section, respectively, of an embodiment of the stator of the motor according to the invention,

FIGS. 4 and 5 are perspective views of variants of this stator, FIGS. 6 and 7 are perspective views, from two different angles, of another variant of the stator of an engine according to the invention, and

- Figure 8 is a perspective view of a complementary housing forming part of an engine equipped with the stator of Figures 6 and 7

Reference is made to FIGS. 2 and 3 of the appended drawing in which a part of the stator of an embodiment of the motor according to the invention has been shown, the parts not shown of this motor being able to conform to the corresponding parts of the motor shown. in Figure 1. This is partially shown in Figure 3 a flange 11 'generally corresponding to the flange 11 of the motor of Figure 1, this flange supporting one of the bearings of the motor rotor and a set of brushes which allows the electrical supply of the rotor of the motor according to the invention. Like that of Figure 1, the stator of Figure 2 comprises a generally cylindrical metal carcass 25 against the inner face of which are fixed two permanent magnets 26ι, 26 ₂ , arranged opposite one another in the meantime ring which separates the stator from the motor rotor.

According to the present invention, the stator further comprises a part 27 of an insulating plastic material, formed in one piece by molding on the metal carcass 25 To facilitate the attachment of this part 27 on this carcass 25, holes 28ι, 28 ₂ , etc. (see Figure 3) can be drilled in the carcass to be filled with the molding material during overmolding, as shown.

By way of illustrative and nonlimiting example, the plastic material for forming part 27 may consist of a polyamide such as PA6, PA66, a polyester such as PBT (polybutylene terephthalate), etc., this material being responsible for fibrous reinforcements.

Part 27 of the stator has several sub-parts associated with different functionalities. Thus it has a sub-portion 27a which takes the form of a flange acting as the flange 10 of the motor of Figure 1, and therefore constituting a shaped means to also support one of the bearings 28 through which passes the motor rotor shaft. This bearing can take the form of the bearing 3 shown in Figure 1 or, advantageously, that described in French patent application No. 97 04964 filed on April 22, 1997 by the applicant. As shown in Figure 3, the bearing then includes an elastic member 29 damping of vibrations interposed between the bearing and the sub-part 27a It will be noted that this sub-part or flange 27a can be provided with radial stiffening ribs such as 30ι, 30 ₂ , etc. capable of reinforcing the mechanical resistance of this subpart 27a. Openings may also be provided in this sub-section for ventilation and cooling of the engine.

Part 27 of the motor has another sub-part 27b, for example in the form of a flat circular collar, placed in a plane perpendicular to the axis X of the motor to act as the disk 15 of the motor in FIG. 1, c ' that is to say participate in the support and fixing of the engine in a device or equipment which receives it, such as the volute of a fan forming part, for example, of a heating, ventilation and / or air conditioning group of the passenger compartment of a motor vehicle, the engine then serving to rotate a set of fins pumping air to create a current of air.

For this purpose, the flange 27b is pierced with holes 31ι, 31 ₂ , 31 ₃ , possibly surrounded by vibration damping washers 32ι, 32 ₂ , 32 ₃ respectively, fixing members such as bolts, screws, etc. being passed in these holes to secure the motor in the device mentioned above, by way of illustrative and non-limiting example only.

Advantageously, the flange 27b is arranged in line with the center of gravity g of the engine so as to promote its balance and facilitate its mounting.

The flange 27b can be provided with a circular distribution of axial lugs such as 33ι, 33 ₂ , etc. molded in one piece with the part 27 and arranged so as to pass in corresponding holes drilled around the base of the flange 11 ′, as shown in FIG. 3, during assembly of the engine. The rotor being passed through the part of the stator shown in this figure, the flange 11 ′ is thus fixed on the part 27 by deformation of the lugs 33, in said holes, by means of ultrasound for example.

Alternatively, as shown in Figure 2, a sub-portion 27c in the form of a ring of the portion 27, attached to the carcass 25, may be provided with radial lugs 34ι, 34 ₂ , etc. to allow mounting to bayonet of the flange 11 ', as described in French patent No. 2,726,700 of the applicant. Such bayonet mounting could also be obtained with axial lugs such as lugs 33, and combined, after assembly, with a deformation of these lugs as explained above. To manufacture the stator shown in Figures 2 and 3, first of all the permanent magnets 26ι, 26 ₂ are fixed in the carcass 25 by any of the means mentioned above for the motor magnets of Figure 1, then place the assembly thus formed in a mold and the part 27 is overmolded on this assembly, the mold being suitably shaped for this purpose

It is understood that this manufacturing process is particularly expeditious in that it offers a reduction in the number of parts to be produced and a reduction in the number of manufacturing operations, therefore a lowering of the cost price of this manufacturing. The precise mounting of the part 27 and the arrangement of anti-vibration members at the level of the bearing 28 and of the crown 27b also ensure an improvement in the quality of the product produced.

FIG. 4 shows a variant of the stator of FIG. 3, which is essentially distinguished by the structure of the assembly constituted by the metal carcass and the elements which it supports. In this variant, this assembly conforms to that described in the French patent application filed on November 17, 1998 by the applicant and entitled "Inductor stator for rotary electric machine, in particular for electric motor".

Such an assembly is then constituted by one or more pairs of metal parts in the shape of a tile 40ι, 40 ₂ , arranged opposite and constituting the metal carcass of the assembly, these parts being embedded by overmolding in a powder 41 of orientable magnetic material with plastic binder, the assembly taking a cylindrical shape on which the part 27 is itself overmolded as described above for the embodiment of FIGS. 2 and 3.

The metal parts can themselves be obtained by compression or fnttage of an iron powder in a mold As- described in the aforementioned French patent application, to which reference will be made for more details, this series of fnttage steps and molding makes it possible to manufacture the engine according to the invention while saving on assembly times and on the material used to manufacture the necessary parts, while improving the quality of the engines obtained thanks to the improvement in dimensional precisions that the molding makes it possible to obtain, precision which makes it possible, in particular, to eliminate games generating vibrations

FIG. 5 shows another variant of the stator of the motor according to the invention, which is distinguished by the shape of the means provided for participating in the support of the motor in the device which receives it. The flange 27b of the previous embodiment is HERE replaced by protrusions 42ι, 42 ₂ , .... cruciform, by example, as shown in the drawing, distributed circularly around the sub-part 27c of the overmolded part 27, in place of the flange 27c These cruciform protuberances are capable of receiving, possibly by overmolding, dampers of elastic material interposed in the mounting between the engine and the host device, to reduce the transmission of vibrations from one to the other. There is shown in Figures 6 and 7 of the accompanying drawing another variant of the stator of the motor according to the invention comprising, like those of Figures 2 to 5, an overmolded part formed of a sub-part 27a constituting a bearing support for the rotor, a ring-shaped sub-part 27c and a set of radial ears 50ι, 50 ₂ , 50 ₃ playing the role of sub-part 27b of the embodiments of FIGS. 3 and 4, for fixing the stator to the device that receives it, or on a piece of interface with this device

To this end, the ears 50ι, 50 ₂ , and 50 ₃ carry lugs 51ι, 51 ₂ , 51 ₃ respectively, arranged so as to pass to mounting in complementary holes of said device or said interface piece, to be fixed in these holes by bolting or using claw washers (not shown).

The perspective view of Figure 7 shows the internal arrangement of the molded part 27. This is molded both on the metal carcass of the stator, which can be made up of two complementary half-rings (not shown), and on two permanent magnets (not shown) Figure 7 shows one (52) of the two overmolded housings on these magnets.

In FIG. 7, axial holes 53 also appear _! , 53 ₂ , ... 53 ₆ provided in the molded part to additionally accommodate axial pins 54ι, 54 ₂ , 54 _3l ... 53 ₆ formed on a flange 55 shown in Figure 8 and complementary to the stator of Figures 6 and 7, for fixing of this flange on this stator, by bolting for example. This flange thus plays the role of the second flange 11 ′ of the motor of FIG. 3.

In the perspective view of FIG. 8, it appears that the flange 55 further comprises various equipment, in particular coal cages 56 _! , 56 ₂ , a connector housing 57 for the electrical power supply to the motor and a housing for an electronic module 58 consisting of an electronic card 59 carrying various electronic components 60, 61, 62 and 63. Such a module can advantageously be integrated to a motor constituted by the stator of FIGS. 6 and 7, a rotor mounted for rotation in this stator and the flange 55 of FIG. 8, to allow the rotation speed of the motor to be varied, by a PWM type control for example . It will be noted that the rotor of the motor is perfectly protected by the enclosure formed by the meeting of the stator and the flange 55 In this regard, it will be noted that the stator of FIG. 6 has two axial ears 64ι, 64 ₂ arranged so as to come cover the open outer ends of the coal cages 56ι, 56 ₂ .The ears 64χ, 64 ₂ thus also provide a retaining function for the springs (not shown) which conventionally charge the coals to the stator.

The flange 55 can be formed from a plastic part, this part thus advantageously integrating a plurality of functional members of the engine.

As a variant of the embodiment of FIGS. 6 to 8, the carbon cages, the connector housing and the housing of the electronic module itself could be integrated into the flange 27a of the molded part 27 of the stator rather than the flange 55 In this assumption, the latter would then only retain its function of protecting the rotor and supporting the second bearing (not shown) thereof, fixed in an axial opening 65 of this housing. The integration of the connector, the electronic module and the coal cages in a flange of the engine is advantageous, not only from the point of view of space, but also from the point of view of cooling. Indeed, the mixing of the air produced by the rotation of the rotor ensures effective cooling of the electronic module, of the connector and of the cages. Of course, the invention is not limited to the embodiments described and shown which have not been given as an example. Thus, in the case of the use of conventional magnets (see FIGS. 2 and 3), the fixing of these magnets in the metal carcass can be ensured by the overmolding of suitable fixing members, simultaneous with overmolding. of part 27, to thus advantageously replace the clips 7, or the bonding mentioned in connection with the description of the embodiment shown in these figures. Likewise, the shock absorber 29 of the bearing 28 (FIG. 3) can also be formed by overmolding of the part 27, just like the shock absorbers possibly carried by the cruciform protuberances of the embodiment of FIG. 5. This is thus again that the invention is not limited to an engine equipped with any of the described embodiments of the means incorporated in part 27 to participate in the support of the engine in a device accommodating said engine. These means can take many other forms, at the choice of those skilled in the art. They can cooperate with the host device either directly or through an interface part which can also take a wide variety of forms.

Claims

R EV ENDICATIONS 1 Electric motor of the type comprising a) a stator (1) generally cylindrical and b) a rotor (2) rotatably mounted in said stator between two bearings integral with the stator, said stator comprising a part (27) of plastic material electrically insulating, formed in one piece by overmolding, said part comprising 1) a first flange (27a) shaped to support one of the bearings (28) of the rotor (2) and 2) a means (27b, 42j, 42 ₂ ) shaped to participate in the support of the motor itself in a device accommodating said motor, the other bearing (4) of said rotor being supported by a second flange (11 '; 55) mounted on said overmolded part (27), characterized in that one of said flanges (27a; l '; 55) incorporates a) charcoal cages (56 _!, 56 ₂ ) for the electrical supply of the motor, b) an electrical connector box (57) and c) a housing for an electronic module (58) for adjusting the motor rotation speed

2. Motor according to claim 1, characterized in that said charcoal cages (56 _!, 56 ₂ ) have open outer ends, covered by ears (64 ₁ , 64 ₂ ) molded in one piece with said overmolded part (27) stator

(1)

3. Motor according to claim 1 or 2, characterized in that said second flange (the; 55) is mounted on said overmolded part (27) via a distribution of pins (33,; 54 .) integral with one and passing through corresponding holes drilled in the other, said pins (33,; 54,) being deformed after their introduction into the holes to ensure the fixing of said flange (11 ', 55) on said stator

4. Motor according to claim 1 or 2, characterized in that said second flange (11 ') is mounted on said molded part (27) via a distribution of lugs (34,) integral with the one and cooperating with corresponding buttonholes formed in the other to ensure a type ^* bayonet connection "

5. Motor according to any one of the preceding claims, characterized in that said part (27) is overmolded on a metal carcass (25) generally cylindrical on the inner face of which is fixed at least one pair of permanent magnets ( 26 _{1 (} 26 ₂ ).

6. Motor according to claim 5, characterized in that the fixing members of said magnets (26ι, 26 ₂ ) on said carcass (5ι, 5 ₂ ) are constituted by overmolded members formed in one piece with said part (27 ).

7 Motor according to any one of claims 1 to 5, characterized in that said overmolded part (27) is formed on a cylindrical assembly consisting of at least one pair of curved metal parts (40ι, 40 ₂ ) arranged opposite l 'from each other and embedded by overmolding in a powder (41) of orientable magnetic material with plastic binder

8. Motor according to any one of the preceding claims, characterized in that said second flange (55) is formed from a piece of plastic injection molding.

9. Motor according to claim 1, characterized in that vibration damping means (29) are interposed between said bearing (28) and said flange

(27a)

10. Motor according to any one of the preceding claims, characterized in that said support means takes the form of a flange (27b) projecting radially from the stator and pierced with a circular distribution of holes (31.) for the passage of engine fixing members on the host device.

11. Motor according to claim 10, characterized in that said holes (31,) are provided with vibration dampers (32,)

12. Engine according to any one of claims 10 and 11, characterized in that said flange (27b) is placed in a plane passing through the center of gravity (g) of the engine.

13. Stator forming part of the engine according to any one of the preceding claims.