WO2001010003A1 - End shield for rotary electric machine - Google Patents

Abstract

The invention concerns a rotary electric machine comprising an axial end shield (10) generally shaped like a metal plate (12) extending in a plane perpendicular to the axis (A) of rotation of the machine rotor which bears at one of its axial ends a header extending through a central opening (14) of the end shield, and wherein the flange (10) carries various electrical elements and components, in particular two brushes (34) extending radially to co-operate with the header, and which includes at least a conductive metal circuit element embedded in an insulating plastic material part (30) extending axially at least partly through catching bores of the end shield and produced moulded around said circuit element and through the catching holes. The invention is characterised in that said moulded plastic part (30) comprises housing (36) for guiding the brushes (34).

Description

 FLANGE FOR ROTATING ELECTRIC MACHINE

The present invention relates to a rotating electrical machine. The invention relates more particularly to an electric motor, in particular of reduced dimensions.

The invention thus relates to a rotary electric machine of the type comprising an axial end flange in the general form of a metal plate which extends in a plane perpendicular to the axis of rotation of the rotor of the machine which carries one of its axial ends a manifold which extends through a central opening of the flange, and of the type in which the flange carries different electrical elements and components, in particular at least two brushes which extend in the radial direction to cooperate with the manifold.

An exemplary embodiment of such a rotary electric machine acting as a wiper motor is in particular described and represented in document US-A-5,309,053 in which the end flange carries a plastic component which is an injection molded part, substantially outside the flange, and in which at least one strip of electrically conductive metal, cut from a metal blank and placed outside, is partially embedded in the overmolding plastic material for constituting electrical connection means comprising areas or parts not covered with the conductive strip for constituting pads or terminals for electrical connection. In known manner, the brushes which cooperate with the collector must be guided radially in a part made of insulating material, each brush being electrically connected to an electric circuit of the motor. It is thus desirable to be able to produce industrially, in particular by allowing mass production and at reduced cost, means forming guide housing for the brushes made of insulating material, in particular plastic, while ensuring mounting and fixing. of these brush guides on the axial end flange so that the latter constitutes a brush-carrying plate, also called contact-carrying plate, in the form of a unitary element.

It has thus already been proposed to produce the entire body of the flange in the form of a plate by plastic molding, in one or more parts, and to fix on this plastic flange other electrical elements and components, as well as electrically conductive elements for making different electrical connection circuits. Such a design is satisfactory from the point of view of the production of the brush holder plate itself, but it has the drawback of reducing the heat dissipation capacity of the flange.

It is of course possible to use a plastic material having improved capacities to dissipate heat, but such a material is expensive and more difficult to mold.

Furthermore, in general, it is desirable to reduce the costs of manufacture, assembly and assembly, in particular by simplifying the assembly and assembly operations, to improve the reliability and the quality of the assembly, in particular from the point of view of its subsequent resistance to vibration, and it is also desirable to propose a design which makes it possible to adapt to the passage of strong currents.

For this purpose, the invention provides a rotary electrical machine of the type mentioned above, characterized in that it comprises at least one conductive metallic circuit element which is embedded in a plastic part insulator which extends at least partly axially through the attachment holes of the flange and which is produced by molding around the said circuit element and through the attachment holes, and in that said plastic part molded includes brush guide housings. According to other characteristics of the invention:

- Each guide housing of a brush is formed inside a box-shaped part which comprises hooking elements which extend axially through a cutout in the metal flange and which are produced from material by molding through the cut;

- Said housing-shaped part comprises an adjacent finger, of axial orientation, produced integrally by molding forming a support for a brush spring; - Said molded plastic part includes supports for an electrical component associated with the brush;

- Said electrical component associated with the brush is a coil comprising a cylindrical core whose axis is parallel to the general plane of the flange, and said supports are forks which extend in parallel planes perpendicular to the general plane of the flange and which are open axially to allow the establishment of the core by axial introduction, in particular of its two opposite ends; said molded plastic part comprises a series of centering and guiding studs for the flange in a stator and / or abutment jacket for ferrites of the stator cylinder head of the machine, which are distributed angularly in the vicinity of the outer radial periphery of the flange and which extend axially from an internal transverse face of the flange;

the axial length of said studs is known to be greater than the axial height of all the other elements and components arranged on said internal transverse face of the flange; - The central part of said molded plastic part defines a cylindrical cavity which receives a mounting and retaining element for a spherical ball for guiding an axial end of the rotor shaft; - Said mounting and retaining elements of the guide ball joint comprises a metal cup comprising an annular cylindrical peripheral skirt which is received in said cavity in which it is mounted axially to trap the ball joint axially; - The metal plate of the flange comprises, in line with the radially inner end of each brush, an axial through hole allowing the introduction, in the radial direction, of a temporary locking finger of the corresponding brush, all of the temporary locking fingers belonging to a removable temporary locking piece;

- The guide ball has a cylindrical opening bore, and the temporary blocking piece comprises a central lug for angular positioning of the ball which, when the temporary blocking piece is mounted on the flange, is received in said bore of the ball guiding;

- Said molded plastic part comprises a portion molded around a peripheral recess of the plate of the flange which receives a complementary part belonging to electrical connection means. Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

- Figure 1 is a perspective view which shows an axial end flange of a rotary electric machine produced in accordance with the teachings of the invention, which is shown with its internal transverse face oriented upwards when considering the figure; - Figure 2 is a perspective view from below of the flange of the fig 1;

- Figure 3 is a perspective view similar to that of Figure 1 su r which is shown only the metal plate constituting the body of the flange and the conductive elements of electrical circuits which are shown exploded above the plate ;

- Figure 4 is a detail view on a larger scale of Figure 1 that i illustrates in particular a brush with its associated choke shown exploded;

- Figure 5 is a detail view on a larger scale of the central part of the flange of Figure 1, in partial section through a vertical axial plane passing through the sliding plane of two opposite brushes, with the temporary blocking part of the brushes in mounted locking position under the flange;

- Figure 6 is a perspective view of the temporary blocking piece of the brushes;

- Figure 7 is a simplified view similar to that of Figure 6;

- Figure 8 is a perspective view of the metal cup for mounting and retaining the ball joint for guiding the rotor shaft;

- Figure 9 is a detail view on a larger scale of a portion of the flange shown in Figure 2 and on which there is also shown the additional electrical connection means of the machine, in particular for its power supply, these means being shown in exploded position relative to the flange; - Figure 1 0 is a view similar to that of Figure 9 on which the electrical connection means are shown in the connected position; and - Figures 1 1 and 12 are two schematic views in axial section illustrating two modes of guidance and electrical connection of the brushes.

In the description which follows, identical, similar or analogous components will be designated by the same reference numbers.

The terms horizontal, vertical, bottom, top, top, bottom, top, etc. will be used, without limitation, to facilitate understanding of the description. in particular with reference to FIG. 1.

There is shown on the figures a flange 1 0 of known general design in the general form of a plate which is intended to constitute the cover or axial closing bearing of an electric motor of which the other components, and in particular the carcass or liner stator and armature rotor, are not shown completely in the figures.

In accordance with the teachings of the invention, the main body of the flange 10 is a metal plate 12 in the general shape of a disc having a circular central opening of axis A perpendicular to the general plane of the plate

12.

The plate 12 is delimited on the outside by a circular edge 1 6, which is folded axially towards the inside of the engine, that is to say upwards when considering FIG. 1, on the one hand to rigidify and the plate 12 and, on the other hand, to constitute means for guiding and centering the flange 10 on the carcass of the engine.

In the embodiment shown in the figures, the plate 12 has three fixing lugs 18 which extend radially outwards, which are angularly distributed evenly around the axis A, and which each has holes 20 fixing. According to a variant not shown, it is possible to overmold in or autou r the holes 20 of the spacers or damping elements.

The metal plate 12 is thus delimited by a flat and smooth external face 22 and by an internal face 24 from which extends axially inwards, that is to say upwards when considering FIG. 3, a flange central reinforcement 26 internally delimiting the opening, or seat, 14 which is produced integrally by deformation with the metal plate 12 and its folded edge 16.

As can be seen in FIG. 3, the central part of the metal plate 12 of the flange 10 has four rectangular cutouts 28 which are angularly distributed at right angles in a regular manner around the axis A and which are arranged centrally at near the circular opening 14.

In accordance with the teachings of the invention, an assembly constituting a molded plastic part

30 is produced by molding on the metal plate 12 according to the injection molding technique in "offset", that is to say that the part 30 with its different functional parts and for attachment and fixing is produced in a single injection molding operation of insulating plastic material by placing the metal plate 12 in an injection mold.

According to one aspect of the invention, the plastic molded part 30 delimits four housings 32 each of which receives a brush 34.

To this end, the part 30 comprises four parts 36 angularly distributed in a regular manner, each of which is formed by molding in line with a cutout 28 of the plate 12. Each part 36 constitutes a box of generally rectangular parallelepiped shape which extends vertically above the internal face 24 of the plate 12.

Each housing 32 has a shape complementary to that of the brush 34 which it receives and it opens out radially to its two opposite radial ends, inner and outer relative to the axis A.

The plastic material for molding the part 30, and in particular the housings 36 extends vertically through the cutouts 28 to constitute, as can be seen in FIG. 2, elements or parts 38 for hooking, each of which is produced here. in the form of a horizontal plate of rectangular outline and of dimensions greater than those of the corresponding cutout 28 so as to extend opposite the parts facing the external face 22 of the plate 12.

The plates 38 therefore constitute, in the embodiment illustrated in the figures, the essential hooking and fixing elements of the plastic molded part 30, these elements being produced at the level of the housings 36 for guiding the brushes 34 which are subjected to efforts.

In order to strengthen the holding of the boxes 36 and to stiffen them, each box 36 comprises, in the vicinity of its inner radial end face 40 through which the brush 34 projects radially inward, two reinforcing wings 44 which s 'extend transversely on both sides and which take support i vertically against the internal face opposite 24 of the plate 12.

Each brush 34 is, in known manner, permanently resiliently urged radially inwards, by a brush spring 46 whose helical body 48, see FIG. 4, is mounted threaded axially on a mounting finger 50 which is read i also produced integrally by plastic molding with the part 30. The flange 10 thus comprises four fingers 50 which are angularly distributed in a regular manner and each of which carries a brush spring 46, 48 of which a branch 52 biases the face of outer radial end of the corresponding brush 34 and the other branch 54 of which is in fixed support in being received in a complementary notch 58 of an adjacent reinforcement wing 44, see FIG. 4.

In known manner, each brush 34 is of course electrically connected by a conductor 60 to an element 62 of the electrical circuit of the flange.

According to a characteristic of the invention, and as can be seen in particular in FIG. 3, the conductive elements 62 of electrical circu it are here produced in the form of two cut metal strips which are initially connected together, this is that is to say before the molding operation of the plastic part 30, by connection zones 64 which are subsequently cut out.

During the molding operation of the plastic part 30, the conductive elements 62 are partially embedded over their longest lengths in parts 66 of shape complementary to those of the strips 62 for isolating the latter, in particular with respect to the metal plate 12.

Each brush 32 is also associated with a choke 68 constituted, in a known manner, by a central cylindrical core 70 and by a peripheral winding 72.

Each of the opposite axial ends 74 of the core

70 constitutes a mounting end, in the same way as the wound body, each of which is received in a bearing fork 76 while the body with its winding 72 is received in two other mounting forks 78.

As can be seen in more detail in FIG. 4, the two pairs of forks associated with each choke 68 are also produced integrally by molding with the part 30.

The forks 76 and 78 thus make it possible to maintain the inductors 68 during their mounting on the brush holder plate, before carrying out the electric welding operations, and this without complicating the mounting process.

The design of the forks is such that they are flexible enough to allow the mounting of each self by elastic deformation of the forks with a slight tightening, and sufficiently rigid to avoid any subsequent vibrations during engine operation.

At its periphery, the plastic molded part 30 also comprises a series of four studs 80 produced integrally by molding and each of which is shaped as an arc of a cylinder for constituting means for guiding and centering the flange 10 to the 'interior of the stator frame, not shown, of the electric motor and / or means for positioning certain parts of the stator, in particular acting as stops for the ferrites of the cylinder head which are generally held in place by clips which, during shocks, can move out of the staples. The presence of the pads makes it possible to limit these displacements and to guarantee their maintenance by the staples.

The four studs 80 are distributed angularly in a regular manner, and their axial length, that is to say their height, considering FIG. 1, is such that it is known above the height of all the other components. and elements of the flange arranged on the internal face 24 of the plate 12.

Thus, in the manufacturing and storage cycle, it is possible to stack several flanges 10 vertically one above the other with the external face 22 of each flange which rests vertically on the free ends 82 of the studs 80 of the adjacent flange , and this without damaging the other elements and components.

Generally known, it is necessary to radially retain the brushes 34 in u rad radially retracted position outward as the flange 10 is not mounted on the motor.

Indeed, as shown schematically in Figure 5, it is necessary that the manifold 84 carried by the axial end 86 of the shaft 88 of the rotor, not shown, of the machine rotating electric can be introduced axially between the brushes 34, that is to say in particular by penetrating between the four end faces 40 of the housings 36, without interfering with the brushes 34 which must then be released in order to cooperate radially towards the inside in contact with the external convex cylindrical surface 85 of the collector r 84.

To this end, each housing 36 comprises, at the right of the corresponding cutout 28, a hole or bore 90 of axial orientation which i opens vertically downwards, considering FIG. 5, outside the flange, and vertically upwards inside the housing 36.

Each hole 90 can be produced integrally by molding with the part 30, 36 and it is capable of temporarily receiving an additional blocking finger 94 which, in the mounted blocking position, extends axially upward, considering the figure. 5, through the hole 90 projecting vertically upwards inside the housing 36 to extend opposite the inner radial face 35 of the corresponding brush 34 and thus to retain the brush 34 which i is elastically stressed by its brush spring 46.

Advantageously, the four locking fingers 94 belong to a temporary locking piece 96 comprising a lower body r in the form of a disc 98 and which is for example a molded plastic part. After the assembly of the motor, that is to say in particular when the manifold 84 is in the axial position relative to the housings 36 and to the brushes 34, it suffices to remove the temporary blocking part 96, axially downwards considering FIG. 5, for simultaneously extracting the four locking fingers 94 outside the holes 90, and therefore for simultaneously releasing the four brushes 34 which, under the action of the springs 46, cooperate with the surface 85 of the manifold 84. In its central part, the temporary blocking piece

96 comprises a cylindrical central pin 1 00 which is designed to be received axially in a cylindrical opening bore 102 formed inside a ball 104 constituting a bearing for guiding in rotation the end 86 of the shaft 88.

Thus, as can be seen in FIG. 5, the pin 1 00 angularly orientates the spherical ball joint 104 in a position such that its bore 102 is oriented axially substantially along the axis A so as to pre-position the ball joint 1 04 relative to the flange 1 00 to facilitate assembly operations, and in particular the axial introduction of the end 86 of the shaft 88 into the bore 102, an operation which is carried out blind.

Thus, the part 96, when it is in position on the flange 10, provides a double function of temporary retention of the brushes 34 and of orientation of the bearing ball 104.

We will now describe the means of mounting and retaining the ball 1 04 inside the flange 1 0.

These means consist essentially of two metal cups 106 and 108.

The first metal cup 106 is a fixed cup forming a seat and the central part of which is shaped to cooperate with the external surface of the ball 104.

This first cup 106 is said to be fixed insofar as it belongs to the flange 10, that is to say that it is permanently fitted in its central part, for example being produced in the form of the central part of the plate 1 2 with its central opening 14.

As a variant, not shown, a fixed cup forming a seat 1 06 could be produced in the form of a metal insert embedded in the plastic part 30. The latter, in its central part, delimits a cylindrical annular recess or cavity 1 10, constituted by the inside of an annular cylindrical plastic collar, which i is open axially upwards and which allows the mounting, axially downwards, of the holding and fixing cup 1 08.

As can be seen in particular in FIGS. 7 and 8, the cup 1 08 is a metal part which i comprises at its lower part a peripheral annular cylindrical skirt 1 12 of shape and dimensions complementary to those of the housing 1 10 , and which is extended centrally by petals 1 14 which pinch elastically the ball 104 in abutment against its lower seat 106, while allowing a relative movement of orientation of the sphere 1 04 around its center.

The petals 1 14 are connected to the skirt 1 12 by u a flat annular flange 1 16 that i, when the movable fixing cup 108 is mounted in place in the housing 1 10, see Figure 7, is in axial support i towards low against a part opposite the lower seat r 106.

Maintaining the cup 108 in the mounted position can be ensured for example by the effect of a force fitting of the skirt 1 12 in the housing 1 10. The fixing can also be completed by other means, for example by gluing, and / or by elastic tabs, not shown, made integrally with the housing 1 10 in the vicinity of the upper axial edge of the latter, and which come to lock axially iller the skirt 1 12 in position in the housing 1 10, by elastic deformation in the manner of clips.

As can be seen in Figure 3, the metal plate 12 has a notch or rectangular window 120 which opens in its circular edge 16. After the molding operation of the plastic part 30, the notch 120 is su rmoulée with plastic material for constituting an electrical connection zone 122 comprising a plate or bottom 124 substantially coplanar with the plate 12 and in which projecting axially outward from the flange 10 of the tabs 126 for electrical connection of the circuits of the flange.

More precisely, as can be seen in FIG. 9, the connection area 122 is in the form of a housing or of a generally closed cavity in the internal axial direction of the motor, a portion of which has been represented diagrammatically. 128 of the stator carcass.

The plastic material molded around the notch 120 for delimiting the cavity 122 extends along the peripheral portions of the external face 22 in the form of a hooking plate 130 which joins the plates 38 of the adjacent housings 36 .

The cavity 1 22 is designed to receive a complementary electrical connection element 1 32 which is generally in the form of a connector comprising in particular two tabs 135 designed to be welded to the tabs 126.

The connection element, or electrical connector, 132 comprises a body of insulating material 1 34 and a first cheek, or plate 1 36, fixed with a generally axial orientation, which is intended to obturate a complementary cut 140 formed in the carcass 128, and a second cheek, or plate 142, of generally horizontal orientation, that is to say perpendicular to the axis A, which is mounted articulated on the body 1 34 to occupy an open position illustrated in Figure 9 and a closed position illustrated in Figure 1 0.

In the open position, the articulated cheek 142 releases access to the connection lugs 134 for the welding operation and it is kept open, in the position shown in FIG. 9, by lugs or clips 144 which are hooked in complementary notches 146.

After electrical connection and welding, the connector 134 is in its position illustrated in FIG. 10 and the horizontal cheek 142 is closed to close the cavity. 122, while being held in the closed position by a clip 148 which cooperates with the edge facing the cheek 142 forming a cover, the articulation of the cheek 142 relative to the body of the connector 1 34 being provided by a thinned part forming film or hinge 1 50 produced integrally by molding with the body 134 of the connector 132 and with the cheek 142.

There is shown schematically in Figure 1 1 a brush 34 of the type described and shown above, that is to say a brush whose body is slidably mounted directly in the complementary housing 32 formed in the housing 36 of plastic material.

In the case of high powers, the plastic material may be insufficient to resist overheating which results from the cooperation of the brush 34 with the collector.

In this case, without departing from the scope of the invention, it is possible to use the assembly shown diagrammatically in FIG. 12 in which the molded plastic part 36 serves as a support for a metal insert 160, around which is molded the plastic material, and which constitutes a guide member of the brush 34 which is slidably mounted on the metal insert 160 which is more resistant to heating than the plastic material mentioned above.

Claims

1. Rotating electric machine, of the type comprising a flange (1 0) of axial end generally in the form of a metal plate (12) which extends in a plane perpendicular to the axis (A) of rotation of the rotor of the machine which carries at one of its axial ends a collector which extends through a central opening (14) of the flange, and of the type in which the flange (10) carries different electrical elements and components, in particular at least two brushes ( 34) that i extend in the radial direction for cooperating with the collector, characterized in that it comprises at least one conductive metallic circuit element that is embedded in a piece of insulating plastic material (30) which s 'extends at least partially axially through the attachment holes of the flange and which is produced by molding autou r of said circuit element and through the attachment holes, and in that said molded plastic part (30) features l brush guiding ogements (36) (34). 2. Rotating electric machine according to the preceding claim, characterized in that each housing for guiding a brush (34) is formed inside a housing-shaped part (36) which comprises hooking elements ( 38) which extend axially through a cutout (28) of the metal flange (10, 12) and which are produced integrally by molding through the cutout. 3. Rotating electric machine according to the preceding claim, characterized in that said box-shaped part (36) comprises an adjacent finger (50), of axial orientation, produced integrally by molding, forming a support for a spring ( 46) broom (34). 4. Rotating electric machine according to any one of the preceding claims, characterized in that said molded plastic part (30) comprises supports for an electrical component associated with the brush. 5. A rotating electrical machine according to the preceding claim, characterized in that said electrical component associated with the brush is a coil (68) comprising a cylindrical core (70) whose axis is parallel to the general plane of the flange, and in that that said supports are forks (76, 78) which i extend in parallel planes perpendicular to the general plane of the flange (1 0) and which are axially open to allow the establishment of the core (70) by axial introduction from its two opposite ends (74). 6. rotary electric machine according to any one of the preceding claims, characterized in that the lad ite molded plastic part (30) comprises a series of studs (80) for centering and guiding the flange in a stator jacket and / or abutment for ferrites of the stator yoke of the machine, which are angularly distributed in the vicinity of the external radial periphery (1 6) of the flange (1 0) and which i extend axially from an internal transverse face (24 ) of the flange. 7. Rotating electric machine according to the preceding claim, characterized in that the axial length of said studs (80) is greater than the axial height of all the other elements and components arranged on said internal transverse face of the flange. 8. Rotating electric machine according to any one of the preceding claims, characterized in that the central part of said molded plastic part delimits a cylindrical cavity (1 0) that i receives an element 1 08 for mounting and retaining a spherical ball joint (104) for guiding an axial end (86) of the shaft (88) of the rotor. 9. rotary electric machine according to the preceding claim, characterized in that said mounting element and retaining the guide ball (104) comprises a metal cup (108) comprising an annular cylindrical peripheral skirt (1 12) which is received in said cavity (1 10) in which it is mounted axially to trap axially the ball joint (104). 1 0. Rotating electric machine according to any one of the preceding claims, characterized in that the metal plate (12) of the flange comprises, in line with the radially inner end of each brush (34), an axial through hole ( 90) allowing the introduction, in the radial direction, of a finger (94) for temporary blocking of the corresponding brush, the set of temporary blocking fingers (94) belonging to a removable part (96) of temporary blocking. 1 1. Rotating electric machine according to the preceding claim taken in combination with the one of claims 8 or 9, characterized in that the guide ball joint (1 04) has a through cylindrical bore (102), and in that the blocking part temporary (96) comprises a central lug (100) for angular positioning of the ball which, when the temporary blocking piece is mounted on the flange, is received in the bore of the guide ball. 12. Rotating electric machine according to any one of the preceding claims, characterized in that the lad ite molded plastic part comprises a molded portion (122, 124) around a peripheral notch (120) of the plate (12) of the flange (10) which receives a complementary part belonging to electrical connection means (132).