FR3075501A1 - ROTATING ELECTRIC MACHINE HAVING A DEVICE FOR HOLDING A SENSOR SUPPORT FOR MEASURING THE ANGULAR POSITION OF THE ROTOR - Google Patents

Abstract

 The invention relates mainly to a rotary electrical machine comprising a rotor mounted on a shaft extending along an axis corresponding to the axis of rotation of the rotor and at least one bearing (18) comprising a housing receiving a bearing for mounting at shaft rotation,  - said rotary electrical machine further comprising a device for measuring the angular position of the rotor comprising:  - a target washer mounted around the tree,  - a support (47) of at least one magnetic field measurement sensor, and  a support washer (51) for the support (47), said support washer (51) being fixed to the bearing (18),  characterized in that the measuring device comprises an axial deformation means (61) of the retaining washer (51) to compensate for deformations of the sensor support (47) in particular due to temperature variations.

Description

ROTATING ELECTRIC MACHINE PROVIDED WITH A DEVICE FOR HOLDING A SUPPORT FOR SENSORS FOR MEASURING THE ANGULAR POSITION OF THE ROTOR

The present invention relates to a rotary electrical machine provided with a device for holding a support for sensors for measuring the angular position of the rotor.

In a manner known per se, rotary electrical machines comprise a stator and a rotor secured to a shaft. The rotor may be integral with a driving and / or driven shaft and may belong to a rotating electrical machine in the form of an alternator, an electric motor, or a reversible machine capable of operating in both modes.

The stator is mounted in a casing configured to rotate the shaft on bearings by means of bearings. The rotor comprises a body formed by a stack of sheets of metal sheets held in the form of a package by means of a suitable fixing system. The rotor has poles formed for example by permanent magnets housed in cavities formed in the magnetic mass of the rotor. Alternatively, in a so-called salient pole architecture, the poles are formed by coils wound around the rotor arms.

Furthermore, the stator comprises a body constituted by a stack of thin sheets forming a crown, the inner face of which is provided with notches open towards the inside to receive phase windings. These windings pass through the notches in the stator body and form buns protruding from either side of the stator body. The phase windings are obtained for example from a continuous wire covered with enamel or from conductive elements in the form of pins connected together by welding.

A device for monitoring the angular position of the rotor of the electric machine comprises a target secured to the shaft of the electric machine associated with at least one magnetic field measurement sensor mounted on a support generally made of a plastic material.

In order to maintain the sensor support, it is known that this support is mounted tight, by means of screws, between a metal washer and the bearing of the machine. However, it has been observed that the plastic of the sensor support tends to deform with the significant variations in temperature undergone by the bearing, so that this causes the tightening torque applied by the washer to the support to be lost. The support can then move relative to the bearing, this causes a loss of precision in the measurement of the angular position of the rotor.

The present invention aims to effectively remedy this drawback by proposing a rotary electric machine comprising a rotor mounted on a shaft extending along an axis corresponding to the axis of rotation of the rotor and at least one bearing comprising a housing receiving a bearing for rotational mounting of the shaft,

- said rotary electrical machine further comprising a device for measuring the angular position of the rotor comprising:

- a target washer mounted around the tree,

- a support for at least one magnetic field measurement sensor,

- a support retaining washer, said retaining washer being fixed on the bearing, characterized in that the measuring device comprises a means of axial deformation of the retaining washer to compensate for deformations of the sensor support, in particular due to variations of temperature.

The invention thus makes it possible, by virtue of the presence of the means for axial deformation of the retaining washer, to guarantee that the sensor support is maintained in position whatever the thermal variations undergone by the bearing of the rotary electric machine.

According to one embodiment, the deformation means comprises at least one stud formed on the sensor support, the stud being arranged to locally deform the retaining washer when the retaining washer is fixed to the bearing.

According to one embodiment, the deformation means comprises a plurality of studs.

According to one embodiment, the studs are arranged circumferentially on the support, so as to be located between two adjacent fixing members of the retaining washer on the bearing.

According to one embodiment, the retaining washer comprises a domed portion intended to come to deform the retaining washer axially, by pressing said domed portion on the sensor support when said retaining washer is fixed on the bearing.

In certain embodiments, it is conceivable to provide a combination of studs formed in the sensor support and curved portions formed in the retaining washer.

According to one embodiment, said rotary electric machine is arranged so that the bearing carried by the bearing, the target washer, then the sensor support is encountered successively, in the direction of the axis of rotation of the rotor.

According to one embodiment, the bearing comprises a housing for the support of sensors.

According to one embodiment, the retaining washer is configured to press an annular flange of the support against a shoulder formed in the housing of the bearing.

According to one embodiment, the device for measuring the angular position comprises means for blocking the support in rotation relative to the bearing. The rotation locking means may include a recess formed in the bearing intended to receive a stud on the support or be constituted by a projection produced in the bearing intended to be inserted in a correspondingly shaped recess formed in the support.

According to one embodiment, the sensor support is made of a plastic material.

According to one embodiment, the retaining washer is made of a metallic material.

According to one embodiment, the target washer extends in a plane perpendicular to the axis of rotation of the rotor.

According to one embodiment, the magnetic field measurement sensor is arranged to measure the magnetic field generated by the target washer in the direction of the axis of rotation of the rotor. In other words, the device for measuring the angular position of the rotor is of the axial reading type.

According to one embodiment, the support carries a plurality of magnetic field measurement sensors.

According to one embodiment, the magnetic field measurement sensor (s) are Hall effect sensors.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

Figure 1 is a perspective view of a rotary electrical machine according to the present invention;

Figure 2 is a perspective view of a rotary electrical machine according to the present invention without the protective cover;

FIG. 3 is a view in longitudinal section of the rotary electric machine according to the present invention;

Figure 4 is a perspective view of the stator and the rotor of the rotary electric machine according to the present invention;

FIG. 5 is a perspective view of the rear part of the electric machine illustrating the mounting of the support for magnetic field measurement sensors according to the invention;

Figure 6 is the same view as that of Figure 5 but without the retaining washer;

FIG. 7 is an exploded perspective view of the rear part of the rotary electric machine comprising the device for measuring the angular position of the rotor according to the present invention;

Figure 8 is a side view showing the axial deformation of the retaining washer by a stud formed in the sensor support according to the present invention.

Identical, similar, or analogous elements retain the same reference from one figure to another.

In the following description, the term “front element” means an element situated on the side of the end of the shaft projecting from the machine (cf. FIG. 3) and by “rear element” an element situated on the opposite side.

Figure 1 shows a rotary electrical machine 10 comprising a polyphase stator 11 surrounding a rotor 12 mounted on a shaft 13 extending along an axis X corresponding to the axis of rotation of the rotor 12. The stator 11 surrounds the rotor 12 with presence an air gap between the internal periphery of the stator 11 and the external periphery of the rotor 12. The stator 11 is mounted in a casing provided with a front bearing 17 and a rear bearing 18. The front bearings 17 and rear 18 comprise each a housing 16 for receiving a bearing in order to ensure rotational mounting of the shaft 13 relative to the casing 14 of the electric machine.

This electric machine 10 could for example be intended to be coupled to a gearbox belonging to a traction chain of a motor vehicle. The electric machine 10 is able to operate in an alternator mode in particular to supply energy to the battery and to the on-board network of the vehicle, and in an engine mode, not only to ensure the starting of the heat engine of the vehicle, but also to participate in the traction of the vehicle alone or in combination with the engine. The power of the machine 10 can be between 10 kW and 50 kW. Alternatively, the electric machine 10 may be installed on an axle of the motor vehicle, in particular a rear axle.

More specifically, as can be seen in Figures 3 and 4, the rotor 12 has a body 19 in the form of a pack of sheets. Permanent magnets 20 are implanted in cavities 21 of the body 19. In the example shown, the magnets 20 are implanted in a V configuration. Alternatively, the magnets 20 are implanted radially inside the cavities 21, the faces in vis-à-vis two adjacent magnets 20 having the same polarity. It is then a configuration with flux concentration.

The magnets 20 may be made of rare earth or ferrite depending on the applications and the desired power of the machine 10.

In addition, the rotor 12 comprises two flanges 22 each fixed against an axial end face of the rotor 12. These flanges 22 provide an axial retention of the magnets 20 inside the cavities 21 and also serve to balance the rotor 12. A spring 25 can be inserted inside each cavity in order to radially hold the magnets 20 inside the cavities 21.

Furthermore, the stator 11 comprises a body 23 constituted by a pack of sheets as well as a coil 24, as shown in FIG. 4. The body 23 is formed by a stack of sheets of sheets independent of each other and maintained in the form of a package by means of a suitable fixing system, such as rivets. The body 23 is provided with teeth 27 defining two by two of the notches 28 for mounting the winding 24 of the stator 11.

The winding 24 comprises a set of phase windings passing through the notches 28 and forming buns 29 projecting on either side of the stator body 23. The phase windings are obtained here from conductive elements in the form of pins, the ends of which are connected together, for example by welding. Alternatively, the phase windings can be obtained from one or more continuous wires.

The phase windings may have a star configuration of the three-phase or double three-phase type. These windings are intended to be connected to an electronic control module via an interconnector 32. This control module comprises a power bridge integrating power elements, such as MOSFET type transistors, as well as a electronic circuit for controlling said power elements.

As can be seen in FIG. 2, the interconnector 32 has connection lugs 33 intended to ensure an electrical connection of the neutral outputs between them, and an electrical connection of each phase output with a terminal 34 of the interconnector 32 corresponding. These terminals 34 are intended to be connected to the aforementioned electronic control module. Alternatively, the interconnector 32 can ensure a triangle connection of the phase windings.

Furthermore, an inlet 37 and an outlet 38 for cooling liquid are arranged to allow the circulation of the liquid inside a chamber 40 extending along the external periphery of the stator 11, as shown in FIG. 3. The liquid could for example be based on water or oil. The chamber 40 is delimited by the external periphery of the front bearing 17 and the internal periphery of the rear bearing 18. Two seals 41 are located at the axial ends of the chamber 40 to ensure its sealing.

The electric machine 10 further comprises a device 44 for measuring the angular position of the rotor 12 of the axial reading type. This measurement device 44, visible in FIG. 3, comprises a target washer 45 mounted around the shaft 13. The target washer 45 extends in a plane perpendicular to the axis of rotation X of the rotor 12. The target washer 45 is made of a magnetic material.

In addition, as can be seen in FIGS. 5 and 6, at least one magnetic field measurement sensor 46 is carried by a support 47 made of a plastic material, in particular made of PA6-6. This sensor 46 is arranged to measure the magnetic field generated by the target washer 45 in the direction of the axis of rotation X of the rotor 12. In other words, the device 44 for measuring the angular position of the rotor 12 is of the type with axial reading. In this case, three sensors 46 are angularly offset from each other in a regular manner. The sensors 46 are advantageously Hall effect type sensors.

Thus, in operation, the rotation of the rotor 12 varies the magnetic field received by the various sensors 46. These sensors 46 transmit to a control unit electrical signals which are a function of the levels of magnetic field received. The control unit processes these signals to deduce therefrom the position of the rotor 12 as well as its speed corresponding to the derivative of the position as a function of time.

As can be seen in FIG. 3, the configuration of the electric machine 10 is such that one successively meets, in the direction of the axis of rotation X of the rotor 12, the bearing carried by the rear bearing 18, the washer target 45, then the sensor support 47.

As can be seen in Figures 6 and 7, the sensor support 47 is located inside a housing 50 of the rear bearing 18. A retaining washer 51 made of a metallic material, advantageously steel, ensures the holding the sensor support 47 against the bearing 18.

To this end, the retaining washer 51 is fixed to the bearing 18 by means of fixing members 53, such as screws, inserted in openings 54 formed in the ears of the washer 51 and corresponding tapped holes 55 formed in balusters 56 of the rear bearing 18. These balusters 56 come from an external periphery of an annular wall delimiting the housing 50.

The sensor support 47 is thus mounted clamped between the washer 51 and the bearing 18. In this case, the retaining washer 51 is configured to press an annular flange 58 of the support 47 against a shoulder 59 formed in the housing 50 of the bearing 18.

Advantageously, as shown in FIGS. 7 and 8, an axial deformation means 61 of the retaining washer 51 makes it possible to compensate for deformations of the support 47 in particular due to temperature variations. Preferably, the deformation means 61 comprises at least one stud 62 formed on the support 47, the stud 62 being arranged to locally deform the washer 51 when the washer 51 is fixed on the bearing 18, as illustrated by FIG. 8 Preferably, a plurality of studs 62 are arranged circumferentially on the support 47, so as to be situated between two adjacent fixing members 53 of the washer 51 on the rear bearing 18.

Alternatively, as illustrated in FIG. 7, the deformation means 61 is constituted by at least one convex portion 64 formed in the washer 51 and intended to come to deform said washer 51 axially by pressing said convex portion 64 on the support 47 when said retaining washer 51 is fixed on the bearing 18.

Of course, in certain embodiments, it is possible to provide a combination of studs 62 formed in the support 47 and curved portions 64 formed in the retaining washer 51.

In order to prevent any displacement of the support 47, it is also possible to provide a locking means 65 for locking the support 47 in rotation relative to the bearing 18, as shown in FIG. 8. The locking means 65 may include a recess formed in the bearing 18 intended to receive a stud 62 of the support 47 or be constituted by a projection produced in the bearing 18 intended to be inserted in a correspondingly shaped recess formed in the support 47.

The interconnector 32 and the rear part of the machine 10 carrying the measuring device 44 are housed inside a protective cover 68 visible in FIG. 1. For this purpose, fixing members 69, such as screws, pass through protruding ears 70 with holes formed in the outer periphery of the protective cover 68 and situated opposite protruding ears 71 with holes of corresponding shape formed in the rear bearing 18.

The signals from the sensors 46 of the measuring device 44 are routed to a connector 73 fixed, by means of screws 74, on the rear face of the protective cover 68 near the phase contact terminals 34.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention from which one would not depart by replacing the various elements with any other equivalent.

Furthermore, the various features, variations, and / or embodiments of the present invention can be combined with one another in various combinations, insofar as they are not incompatible or mutually exclusive of each other.

Claims (15)

1. Rotating electric machine (10) comprising a rotor (12) mounted on a shaft (13) extending along an axis (X) corresponding to the axis of rotation of the rotor (12) and at least one bearing (18) comprising a housing (16) receiving a bearing (15) for the rotational mounting of the shaft (13), - said rotary electrical machine (10) further comprising a device (44) for measuring the angular position of the rotor (12) comprising: - a target washer (45) mounted around the shaft (13), - a support (47) of at least one magnetic field measurement sensor (46), - a retaining washer (51) of the support (47), said retaining washer (51) being fixed on the bearing (18), characterized in that the measuring device (44) comprises an axial deformation means (61) of the retaining washer (51) to compensate for deformations of the sensor support (47) in particular due to temperature variations. 2. Rotating electric machine according to claim 1, characterized in that the deformation means comprises at least one stud (62) formed on the support (47) of sensors, the stud (62) being arranged to locally deform the retaining washer (51) when the retaining washer (51) is fixed on the bearing (18). 3. Rotating electric machine according to claim 2, characterized in that the deformation means comprises a plurality of studs (62). 4. rotary electric machine according to claim 3, characterized in that the studs (62) are arranged circumferentially on the support (47), so as to be located between two adjacent fixing members of the retaining washer (51) on the bearing (18). 5. rotary electrical machine according to claim 1, characterized in that the retaining washer (51) comprises a curved portion (64) intended to come to deform the retaining washer (51) axially, by pressing said curved portion (64) on the sensor support (47) when said retaining washer (51) is fixed on the bearing (18). 6. rotary electric machine according to any one of claims 1 to 5, characterized in that it is arranged so that one meets successively, in the direction of the axis (X) of rotation of the rotor (12) , the bearing (15) carried by the bearing (18), the target washer (45), then the sensor support (47). 7. Rotating electric machine according to any one of claims 1 to 6, characterized in that the bearing (18) comprises a housing (50) for the support of sensors (47). 8. rotary electric machine according to any one of claims 1 to 7, characterized in that the retaining washer (51) is configured to press an annular collar of the support (47) against a shoulder (59) formed in the housing of the bearing (18). 9. rotary electric machine according to any one of claims 1 to 8, characterized in that the device for measuring (44) the angular position comprises a means for locking the support in rotation (47) relative to the bearing (18) . 10. Rotating electric machine according to any one of claims 1 to 9, characterized in that the sensor support (47) is made of a plastic material. 11. Rotating electric machine according to any one of claims 1 to 10, characterized in that the retaining washer (51) is made of a metallic material. 12. Rotating electric machine according to any one of claims 1 to 11, characterized in that the target washer (45) extends in a plane perpendicular to the axis of rotation of the rotor (12). 13. rotary electric machine according to any one of claims 1 to 12, characterized in that the magnetic field measurement sensor (46) is arranged to measure the magnetic field generated by the target washer (45) in the direction of the axis (X) of rotation of the rotor (12). 14. Rotating electric machine according to any one of claims 1 to 13, characterized in that the support (47) carries a plurality of sensors (46) for measuring magnetic field. 5 15. Rotating electric machine according to any one of claims 1 to 14, characterized in that the one or more sensors (46) for measuring the magnetic field are Hall effect sensors.