KR20070058490A - Rotor armature of an electric starter motor with partial impregnation and motor vehicle starter comprising one such armature - Google Patents

Abstract

The invention relates to a rotor armature of an electric motor, comprising a rotor winding which is partially impregnated with an impregnating agent along a pre-determined axial distance (v) which extends from the rear coil (43) in the weld zone (44) in which the ends of the conductors (41) are welded to the bars (45) of the commutator (23) as far as an intermediate position of the magnetic circuit (39), such as to leave the front coil (42) free from impregnation in order to increase the heat exchange surface thereof. The invention is suitable for motor vehicle starters.

Description

ROTOR ARMATURE OF AN ELECTRIC STARTER MOTOR WITH PARTIAL IMPREGNATION AND MOTOR VEHICLE STARTER COMPRISING ONE SUCH ARMATURE}

The present invention relates to a rotor having a semi-open notch, a current collector, a rotating output shaft supporting a magnetic circuit with a starter head, a leading out wire located on the starter head side; A rotating armature of an electric starter motor comprising a winding of a rotor having conductors projected to each side of a magnetic circuit and housed in a semi-opened notch to construct a rear leading out wire disposed on the current collector side.

According to the known technique, the conductor wires belonging to the windings of the armature of the rotating electric machine, in particular for the starter of the internal combustion engine of the motor vehicle, are in the notch and front end of the bundle of metal sheets in the notch of the magnetic circuit consisting of the bundle of metal sheets. It is fixed by an impregnation lacquer that causes adhesion between the wire and the housing.

The document EP-A-881747 refers to an alternator stator that is fixed when the conductor part housed in the notch is affected during the impregnation operation and is not affected by centrifugal forces. The impregnant occupies the total axial length of the notch, and the insulated layer is less thick in the leading out wire than in the conductors in the notch.

Use a hoop of fiberglass on the front and / or rear leading-out wire on the collector side on the starter head side, or as described in document FR-A-2721769, cream the inlet of the notch to secure the conductor. Further other fastening means of crimping are sometimes used to reinforce the mechanical strength of the wires in the notches.

The means of inserting the impregnating lacquer are extremely limited and there are expensive costs of lacquer, electrical energy supplied to the impregnation machine and heating oven, complex maintenance operations, and in the front leading-out wire, the lacquer is placed around the copper conductor Two problems arise: creating a kind of obstacle to soften the roughness and blocking the gap to reduce the heat exchange surface between the wire and the surrounding air, thereby weakening the heat resistance of the starter with the risk of excessive heating.

It is an object of the present invention, in particular, to propose a rotating armature of an electric starting motor which does not have an internal gearbox and compensates for this drawback.

The rotating armature of the electric starter motor according to the present invention has a predetermined length in which the winding of the rotor extends from the rear leading out wire in the conductor end soldering area to the blade of the current collector so as not to impregnate the front leading out wire and increase its heat exchange surface. It is characterized in that it is partially impregnated with the impregnant up to the distance of the middle point of the magnetic circuit along the axial length of the. The axial winding impregnation length is shorter than the total length of the magnetic circuit.

The impregnation agent generally consists of a lacquer which is deposited only on the armature rear portion on the collector side. Lack of lacquer deposited on the front leading-out wire on the starter head side increases the fluctuations of the ambient air in this area and results in less significant loss of power than in the leading-out wire impregnated in the heating experiment. Therefore, the thermal resistance of the starter is improved. Another advantage is that the lacquer can be saved without reducing the resistance of the centrifugal force during the armature rotation.

In a preferred embodiment, the intermediate point at which the impregnation is stopped is located between one half and two thirds of the axial length of the bundle of metal sheets constituting the magnetic circuit. The conductor is held in the notch by fastening means actuated by crimping the magnetic circuit to narrow the inlet of the notch.

The fastening means is constructed by crimping the nose at at least one or more latching points of the magnetic circuit, the intermediate front and rear ends of the magnetic circuit on the collector side being closer to the unimpeded front leading out wire than the impregnated rear leading out wire. Other technical features of the invention may be used alone or in combination, provided with an elastic washer separated by an axial distance from the fixation point, supported by a cover to protect the rotating armature, and closing the brush housing to filter vibrations. .

1 is an axial sectional view of a starter having an armature rotor according to the present invention,

2 is an axial cross-sectional view of the armature rotor of FIG. 1 showing the distribution of latching of a thin metal sheet for mechanical strengthening of conductive wires in a notch, FIG.

3 shows a partial impregnation area of the armature rotor of FIG. 1, FIG.

4 is a radial cross-sectional schematic diagram of an armature leading out wire with impregnation lacquer according to the prior art,

5 shows the armature without impregnation lacquer and leading out wire according to the invention in the same manner as in FIG.

In FIG. 1, the starter 10 for starting the heat engine of the motor vehicle includes a support 11 which is designed to be fixed to a fixed part of the motor vehicle. The support 11 has a nose 12 for mounting a front bearing 13, for example a needle bearing, which is coaxially belonging to the starter head 15.

The front end of the tubular sleeve 14 is formed to constitute a control pinion 16 protruding from the nose portion 12 to engage with an associated starting ring (not shown) for starting the heat engine of the motor vehicle.

The rear end of the tubular sleeve 14 of the starter head 15 is arranged in a circular inner track for the roller 17 belonging to the freewheel inserted between the pinion 16 and the drive 18.

The drive 18 has an internal flute 19 which is engaged with an external flute 20 which is integral with the output shaft 21 of the rotor 22 belonging to the electric motor M of the starter. . The flutes 19 and 20 have a complementary spiral.

On the shaft 21 of the rotor 22 opposite the starter head 15, a shaft type current collector 23 described in, for example, French Patent Application Publication No. FR-A-2 722 037 is conventionally used. Provided in a manner. The radially actuated brush 24 rubs the conductive axial blades of the current collector 23.

For this purpose the brush 24 is mounted in a housing of a brush holder comprising a body (not shown in FIG. 1) configured to act as a spring support, each spring being radially mounted in a housing of the brush holder, Associated with the brush 24, the brush is pressed in the direction of the electrically conductive blade of the current collector 23.

The rear end of the output shaft 21 is rotatable to the rear bearing 25, such as a plain bearing, supported by a central sleeved portion of the cover 26 described as an example of FR-A-2726701 document. Is mounted.

The casing 27 is arranged between the cover 26 and the support 11 and mounts the stator 28 with an induction coil 28 which coaxially surrounds the rotor 22 with a radial air gap. Contribute. A tie rod 30 connects the cover 26 and the casing 27 to the support 11.

More precisely, as described in the document FR-A-2726701, the stator includes a bundle of cut metal sheets that defines the housing (not shown) of the electrical coil 29.

Each of the two end faces of the axial end of the metal sheet bundle of the stator has a cheek made from a plastic material (not shown in FIG. 1). The cheek portion contributes to winding the coil 29. Washers (not shown) serve to close the housing of the brush 24. Therefore, the housing is bounded by a plastic body (not shown) of the brush holder and a local nose portion of the cover 26 and a washer supported in the body. The main body of the brush holder is in contact with an adjacent side surface. The washer filters the axial vibration and is also elastic. For further information refer to the document FR-A-2726701 (especially FIG. 1). Therefore, the washer protects the brush and the rotating armature described below.

The support 11 also serves to mount the cell 31 belonging to the electromagnetic contactor CT located parallel to the electric motor M. In a known manner, the contactor CT has a fixed terminal 32, at least one excitation winding 33, a movable core 34 and a fixed terminal 36, 37 for supplying electricity to the electric motor M. FIG. A movable contact 35 designed to cooperate. The fork shaped control lever 38 is pivotally mounted to the shaft of the rod elastically coupled to the movable core 34. The lower part of the fork comprises two fingers mounted in an annular groove in the drive 18 of the starter head 15.

The rotor 22 is formed of a magnetic circuit 39 formed of a stack of essentially thin metal plates, for example forcibly fitted by at least one node of the shaft 21 to be mounted in the axial direction of the output shaft 21. ). Each metal sheet includes a plurality of notches 40 semi-open in the radial direction from the outer circumference to the outside. The notches 40 are distributed at regular intervals and form an axial groove along the metal sheet.

Each notch 40 receives a coiled electrical conductor 41 that passes through the magnetic circuit 39 of the rotor 22. The conductor 41 is axially formed on each side of the magnetic circuit 39 to form the front leading out wire 42 on the starter head 15 side and the rear leading out wire 43 on the collector 23 side, respectively. Protrudes and extends. The front leading out wire 42 is composed of the head of the conductor 41 and the rear leading out wire 43 includes the end of the conductor 41 designed to be connected to the conductive blade of the current collector 23.

Advantageously, the notch insulator is particularly between the conductor 41 and the cross section that borders the notch 40 in order not to damage the conductor or more precisely the electrical insulator such as the sheath or enamel 47 shown in FIGS. 4 and 5. Is inserted. The insulator 47 surrounds the conductor 41, for example made of copper.

The notch insulator is integral with the bundle of metal sheets constituting the body of the rotor 22, which is a component of the magnetic circuit 39 or more precisely the shaft 21.

In FIGS. 1-3 a series of superimposed conductors 41 are provided per notch 40 to produce the rotor windings. For example, four conductors 41 are provided per winding and superimposed in the notch 40 during the winding operation. The wire is initially crushed with a circular cross section as can be clearly seen in FIGS. 4 and 5 after the compression operation with a plate-shaped tool with a crimpim punch. The thin metal lamination of the magnetic circuit 39 is, for example, latched onto each wire by crimping punches of the plate-shaped tool, in particular at three, one or more latching points A, B, C in FIG. 2. . Latching is achieved by the crimping method described, for example, in the document FR-A-2721769, which consists of locally bending the steel part over the notch 40 to narrow the notch's inlet to prevent the wires from escaping. It is.

Mechanical reinforcement of the conductor 41 in the notch 40 is thus provided by the adhesion of the three peripheral latching points A, B, C and the contact of the conductors, which are inserted into each other and press the inner wall of the notch 40, respectively. do. According to the invention it is supplemented by partially impregnating the rotor windings with a lacquer. Referring to FIG. 3, the impregnation part is located behind the armature on the side of the current collector 23, that is, the point where the mechanical strength of the wire on which the centrifugal force acts during the rotation of the current collector 23 reaches a threshold. The amount of lacquer deposited on the notch 40 is reduced.

The front leading out wire 42 of the starter head 15 has no lacquer or other impregnating agent except the insulating sheath of the wire. The impregnation area of the conductor 41 with lacquer is the magnetic circuit 39 over the axial distance v from the end soldering area 44 of the conductor 41 to the electrically conductive blade 45 of the current collector 23. Extends to a distance of approximately 1/2 or 2/3 of the total length z. The active area u of the blade 45 of the current collector 23 also does not have an impregnation lacquer coating.

The latching points A, B, and C are separated from the rear part of the magnetic circuit 39 on the current collector side by the predetermined distances I1, I2, and I3, respectively, and the middle fixing point B is the rear of which the lacquer is impregnated. It is closer to the unleashed front leading out wire 42 than the leading out wire 43.

Lack of lacquer in the front leading out wire 42 results in an increase in the exchange surface between the conductor and the ambient air. 4 shows that the heat exchange surface S of the leading out wire with the impregnation lacquer 46 according to the known art is smaller than the heat exchange surface S 'of the leading out wire without the impregnation lacquer shown in FIG. 5. have. In both cases each conductor 41 is electrically insulated in a normal manner by an insulating sheath 47 or by an enamel layer for electrical insulation between the various wires.

Increasing the exchange surface of the front leading out wire 42 provides for better internal ventilation of the starter and improves heat resistance while at the same time saving lacquer and simplifying the impregnation device when the electric motor M is manufactured. The use of an additional hoop to radially retain the conductive wire 41 in the leading out wires 42, 43 is not essential.

The principle of partial impregnation can be applied to any kind of wound armature, as well as to hairpin windings of the kind described in document FR-A-2244284. The field of application relates to all types of starters for starting the heat engine. This field relates in particular to starters of all light or heavy duty vehicles, and in particular to starters without internal gearboxes, where the rotor rotation speed is low, thereby minimizing the risk of centrifugal forces of conductive wires.

The elastic washers of the brush holders described above dampen axial vibration to protect the lacquer-free front leading out wire.

It is clear that the collector 23 can be a brush of the forward type and of the axial actuation type. The pinion 16 of the starter head 15 can likewise be mounted in the support 11.

The freewheel operating between the pinion 16 and the drive 18 of the starter head 15 is connected to the concave friction surface belonging to the pinion 16 or the starter head 15 and to one of the components consisting of the starter head and the pinion. It may also be formed as a friction clutch comprising a convex friction surface to which it belongs.

According to another variant, the contactor CT can be mounted perpendicularly to the axis of the output shaft 21 at the rear of the electric motor M. The fork of the control lever 28 is connected to a supplementary rod extending parallel to the electric motor M at its upper end and a return mechanism that operates between the rod coupled to the movable core 34 and the supplementary rod FR-A-2. 843 are combined as described in 427. In a variant, the contactor is mounted in front of the electric motor, and the movable core of the contactor consists of a starter head in which the presence of the control lever 38 is not mandatory.

The number of conductors per notch depends on the application.

Claims (10)

In the rotating armature of the electric starter motor (M), A rotor having a semi-opened notch 40, a current collector 23 and a rotating output shaft 21 for supporting the magnetic circuit 39 with the starter head 15, Semi-open notch protruding to each side of the magnetic circuit 39 to form the front leading out wire 42 located on the starter head 15 side and the rear leading out wire 43 arranged on the collector 23 side. A winding of the rotor having a conductor 41 housed in 40; In order to prevent the front leading out wire 42 from being impregnated to increase its heat exchange surface, the windings of the rotor are connected to the blades of the current collector 23 from the rear leading out wires in the soldering region 44 at the end of the conductor 41. Characterized in that it is partially impregnated with the impregnant up to the intermediate point distance of the magnetic circuit 39 along a predetermined axial length v extending up to 45. Rotating armature of electric starter motor. The method of claim 1, The axial winding impregnation length v is shorter than the total length z of the magnetic circuit 39 Rotating armature of electric starter motor. The method of claim 2, Characterized in that the intermediate point at which the impregnation is stopped is located between 1/2 and 2/3 of the axial length z of the bundle of metal sheets constituting the magnetic circuit 39. Rotating armature of electric starter motor. The method of claim 1, The conductor 41 is characterized in that it is held in the notch 40 by fastening means actuated by crimping the magnetic circuit 39 to narrow the inlet of the notch 40. Rotating armature of electric starter motor. The method of claim 4, wherein The fastening means is characterized in that it crimps the nose at at least one or more latching points A, B, C of the magnetic circuit 39. Rotating armature of electric starter motor. The method of claim 5, The front and rear ends of the magnetic circuit 39 on the side of the current collector 23 are separated by the axial distances I1, I2, and I3 from the fixing points A, B, and C, and the intermediate fixing point B Is closer to the unimpregnated front leading out wire than to the impregnated rear leading out wire. Rotating armature of electric starter motor. The method of claim 1, The impregnant is a lacquer, characterized in that Rotating armature of electric starter motor. The method of claim 7, wherein Said conductor 41 of said rotor winding is formed by a wound wire or hairpin Rotating armature of electric starter motor. In a motor vehicle starter having a rotating armature and comprising an electric motor M controlled by a contactor CT, A rotating armature according to claim 1 is provided Motor vehicle starter. The method of claim 9, A shaft of the rotor 22 in a rear bearing supported by a central portion of the cover 26, comprising a brush holder provided with a body for partitioning the housing for the brush in friction with the conductive blades of the current collector with an elastic washer; A rear end of the 21 is rotatably mounted, and an elastic washer is supported on the cover and closes the brush holder housing to filter vibrations. Motor vehicle starter.

Images