CN114788148A - Rotating electric machine including temperature sensor - Google Patents

Abstract

The invention proposes a rotating electrical machine with an axis X, comprising: a shaft (13) supporting a rotor (12) surrounded by a stator (15) supported internally by a front bearing (16) and a rear bearing (17) connected to each other; an electronic assembly (36) axially mounted on the rear bearing (17) comprising power electronics (37) and control electronics (38); a sensor (50) for sensing the rotor position, the sensor being associated with an object (51), the object (51) being fixed on an object carrier (510) which is rotatably wedged in the rotor (12) and axially implanted between the rotor (12) and the rear bearing (17), the position sensor (50) comprising a detection portion (52) designed to detect the passage of the magnetic object (51) and a portion for electrical connection of the position sensor to electronics (53), the detection portion of the position sensor (52) being supported by the electronic assembly (36); temperature sensor (40) comprising a measuring probe (401) designed to locally measure a temperature, and an electrical connection portion (402) for electrically connecting the temperature sensor to the electronics, characterized in that the temperature sensor (40) is supported by a position sensor (50).

Description

Rotating electric machine including temperature sensor

Technical Field

The technical field of the present invention relates to rotating electrical machines, in particular for motor vehicles, wherein a temperature sensor is positioned to provide a reliable temperature measurement.

The invention is applicable in the field of rotating electrical machines, such as alternators or reversible machines that can operate as generators or as motors.

Background

As is well known, a rotary electric machine includes a stator and a rotor integrated with a shaft. The rotor may be rigidly connected to the drive shaft and/or the driven shaft and may form part of a rotating electrical machine in the form of an alternator, an electric motor or a reversible electrical machine of the alternator-starter type that can operate in both modes.

The stator is mounted in a housing configured to rotate the shaft on bearings via roller bearings. For example, the rotor is of the "claw rotor" type and comprises two magnetic wheels, each having claws which are imbricated inside each other to form magnetic poles and a core on which the rotor coils are wound. According to another example, the rotor comprises a body formed by a stack of metal plates, which are held in groups by means of a suitable fixing system. The rotor comprises poles, for example formed by permanent magnets, which are housed in cavities provided in the magnetic body of the rotor. Alternatively, in the so-called "salient" pole architecture, the poles are formed by coils wound on the rotor arm.

Appropriately positioned temperature sensors may measure or estimate the temperature of various components as the motor and electronic assembly are cooled by ambient air, thereby preventing overheating of the motor. These sensors are typically located within the electronic assembly. In the case of electronic components cooled by liquid, for example for cooling the electric circuit of a vehicle in which the electric machine is installed, and in the case of electric machines cooled by ambient air, the temperature sensor located in the electronic component may no longer give sufficiently reliable information from the outside air. In this case, the estimation of the temperature of the motor, in particular of the rotor and stator, may no longer be performed with the required accuracy. Since a rather high accuracy is necessary in order to avoid unnecessarily inhibiting the performance of the motor, another solution has to be determined to estimate or measure the temperature of the motor.

In the motor according to the prior art described in patent document FR3046507, the temperature sensor is clamped on the stator winding. The installation of this type of temperature sensor is difficult to achieve and expensive. In fact, the form of the bun formed by the stator winding may not have an area that easily incorporates a temperature sensor. Most implemented solutions require that resin be placed in place on the stator bun, which increases the risk during production, especially the risk of contamination of the rotor or stator. Furthermore, the temperature measurement obtained by positioning this type of temperature sensor is difficult to represent the motor temperature.

Disclosure of Invention

The present invention aims to make it possible to avoid the drawbacks of the prior art.

To this end, it is an object of the invention to integrate a temperature sensor into a sensor that has been used to determine the position of the rotor of an electric machine.

According to the invention, a rotary electric machine having an axis X comprises: a shaft supporting the rotor surrounded by a stator, the stator being supported at an inside thereof by a front bearing and a rear bearing connected to each other; an electronics assembly axially mounted on the rear bearing, including power electronics and control electronics; a sensor for the position of the rotor, the sensor being associated with an object, the object being fixed on an object carrier, the object carrier being rotatably wedged onto the rotor and being axially implanted between the rotor and the rear bearing, the position sensor comprising a detection portion designed to detect the passage of the magnetic object, and a portion for electrically connecting the position sensor to the electronics, the detection portion of the position sensor being supported by the electronic assembly; a temperature sensor comprising a measuring probe designed to locally measure a temperature and a portion for electrically connecting the temperature sensor to the electronic device, characterized in that the temperature sensor is supported by a position sensor.

The invention thus makes it possible to obtain a more reliable temperature measurement, in view of the positioning of the temperature sensor in the vicinity of the position sensor in the axial air flow of the electrical machine, as will be described hereinafter. The invention thus makes it possible to obtain temperature measurements that are much simpler to combine and therefore considerably limit the costs. Furthermore, the connection of the temperature sensor to the electronic device is thus made easy, and the cost thereof is limited.

According to an embodiment, the detection portion of the position sensor and the measuring probe of the temperature sensor are positioned in an angular sector around the motor axis, which is less than 180 °, advantageously less than 90 °.

According to an embodiment of the invention, the measurement probe of the temperature sensor is positioned axially between the rear bearing and the electronic assembly.

According to an embodiment of the present invention, the measurement probe of the temperature sensor is supported by the detection portion of the position sensor.

According to an embodiment of the invention, the electric machine comprises a sensor carrier in which the sensing part of the position sensor and the measuring probe of the temperature sensor are enclosed.

According to an embodiment of the invention, the sensor carrier comprises at least one first portion and one distinct second portion, the first and second portions being circumferentially adjacent around the axis of the electrical machine and being connected to each other by a third portion, the first portion overmoulding the sensing portion of the position sensor, the second portion overmoulding the measurement probe of the temperature sensor.

According to an embodiment, the measuring probe of the temperature sensor is supported by the connecting portion of the position sensor.

According to an embodiment, the connection portions of the temperature sensor and the position sensor have a common ground, which is electrically connected to the ground of the control electronics.

Drawings

Fig. 1 schematically and partially shows a cross-sectional view of a rotating electric machine according to an embodiment of the invention.

Fig. 2 is a perspective view of the electronics of the motor containing the position sensor.

FIG. 3 is a cross-sectional view of the position sensor.

Fig. 4 shows an electrical assembly of a position sensor with control electronics according to a first embodiment of the invention.

Fig. 5 schematically shows the air flow in the motor.

Fig. 6 is an assembly view of a temperature sensor on a position sensor according to a second embodiment of the present invention.

Detailed Description

In the following description, "axial" means extending along the axis of the machine, while "orthogonal radial" means extending according to an angular sector around the axis of the machine, in a plane transverse to the axis of the machine.

Fig. 1 shows a compact multiphase alternator 10, particularly for a motor vehicle. Such alternators convert mechanical energy into electrical energy and are reversible. The reversible alternator, known as the alternator-starter, can convert electrical energy into mechanical energy, in particular in order to start the thermal engine of the vehicle.

The alternator 10 comprises a housing 11, and inside the housing a claw rotor 12 and a stator 15, the claw rotor 12 rotating directly or indirectly integrally with the shaft 13, the stator 15 surrounding the rotor 12 and presenting an air gap. The axis X-X of the shaft 3 forms the axis of rotation of the rotor 12.

In the following description, the radial, transverse and axial directions are considered relative to the axis X-X.

The stator 15 comprises a body in the form of a set of metal plates 27, which metal plates 27 are provided with notches, for example of the semi-closed type, which are equipped with notch insulation for fitting the stator phases, each phase comprising at least one winding, which passes through the notches of the stator body and forms, together with all phases, a front bun 29 and a back bun 30 on both sides of the stator body.

The windings are obtained, for example, from continuous wires covered with enamel, or from conductive elements in the form of bars, such as pins connected to each other, for example, by welding.

These windings 28 are, for example, three-phase windings connected in star or delta form, the outputs of which are electrically connected to electronic components 36 described below.

The rotor 12 comprises two magnet wheels 31. Each wheel 31 has a transversely oriented plate 32, which plate 32 is provided on its periphery with claws 33, the claws 33 having, for example, a trapezoidal shape and an axial orientation. The claws 33 of one magnetic wheel 31 face axially towards the plate 32 of the other wheel, the claws 33 penetrating into the space existing between two adjacent claws 33 of the other magnetic wheel, so that the claws 33 are imbricated.

The outer circumference of the claws 33 has an axial orientation and defines, together with the inner circumference of the stator body, an air gap between the stator 15 and the rotor 12.

The plate of the wheel 32 has an annular shape.

A cylindrical core 34 is inserted axially between the plates of the wheel.

Between the core and the claw 33, the rotor 12 comprises a coil 35 comprising a hub and an electrical winding on the hub.

In the example described, the hub is made of an electrically insulating material, for example a plastic material, while the magnetic wheel 31 and the core are made of metal, in this case a ferromagnetic material, for example mild steel. The shaft 13 is also metallic and made of a ferromagnetic material, such as steel, which is harder than the core of the magnet wheel and the claw rotor.

The housing 11 includes a front bearing 16 and a rear bearing 17 assembled together. The rear bearing 17 supports the brush holder 24, the voltage regulator and at least one rectifier bridge.

The bearings 16 and 17 have a hollow form and each centrally supports a ball bearing, respectively 18 and 19, for mounting the shaft 13 of the rotor 12 with rotation.

The pulley 20 is fixed to the so-called front end of the shaft 13, for example by means of a nut supported on the base of the cavity of the pulley.

The front end of the shaft 13 supports a pulley belonging to the means for transmitting motion to at least one belt between the alternator and the thermal engine of the motor vehicle, while the rear end 6 of reduced diameter of the shaft 3 supports a slip ring connected by a wired connection to the winding. Brushes belonging to the brush holder are positioned to rub on the slip rings. The brush holder is connected with the voltage regulator.

The slip rings belong to the current collector 22. In addition to the slip ring 21, the collector 22 also comprises an electrical connection lug which is deformable to ensure electrical connection with the winding. These lugs are electrically connected to the slip ring.

When the field winding is energized by the brushes, the rotor 12 is magnetized and becomes an induction rotor, forming north-south magnetic poles on the claws and thus on the claws of the magnet wheel.

When the shaft 13 rotates, the induction rotor generates an alternating current induced current in the induction stator, the rectifier bridge of said electronic assembly 36 then making it possible to convert the induced alternating current into a direct current, in particular for powering the chargers and consumers of the on-board network of the motor vehicle, as well as recharging the batteries of said vehicle.

The rotor 12 may comprise permanent magnets placed between two adjacent claws on the outer circumference of the rotor. As a variant, the rotor 12 may be devoid of such magnets.

The front bearing 16 and the rear bearing 17 comprise substantially transverse openings for the passage of air, in order to allow cooling of the alternator by the circulation of air generated by the rotation of a fan 26 (called rear fan), the fan 26 being on the rear back of the rotor, i.e. at the rear bearing 17. Each fan 25, 26 is fixed to the respective magnetic wheel, for example by screws, rivets or spot welding.

The machine therefore also comprises an electronic assembly 36, in this case an electronic assembly 36 mounted on the casing 11, comprising at least one electronic power module 37, making it possible to control at least one phase of the winding 28. The electronic power module 37 forms a voltage rectifier bridge in order to convert the generated alternating voltage into a direct voltage and vice versa. The electronic power module advantageously comprises a capacitor and a power module consisting of MOSFETs.

The electronics assembly 36 also includes an electronic control module 38 that includes a control panel. Fig. 2 shows the assembly of the electronic power module 37 and the electronic control module 38.

The position of the rotor 12 may be measured by a sensor 50 for the position of the rotor, which is also shown in fig. 2 and is supported by the electronics assembly. The position sensor 50 cooperates with a magnetic target 51 to provide information relating to the angular position of the rotor.

The magnetic target 51 (commonly referred to as a magnetic encoder) is, for example, a magnet. The magnetic element 51 is rotationally wedged into the rotor 12. This wedging may be physically accomplished by positioning the encoder and magnetic wheel relative to each other, or simply by software after the motor is assembled. The target is fixed, for example, on a target carrier that rotates integrally with the rotor 12. The target is axially implanted between the rotor and the rear bearing.

The position sensor axially passes through an opening in the rear bearing to be positioned facing the target.

The position sensor includes a sensing portion 52 supported by the rear bearing. The sensing portion includes, for example, three position probes 520, which are, for example, hall effect probes. These probes are supported by the sensor carrier 54 and are each electrically connected to the control board of the control electronics. The sensor carrier 54 is a container, for example made of plastic, in which the hall effect probe is accommodated, for example by moulding or welding.

These probes are adjacent to each other, positioned orthogonally radially facing the target, forming the detection portion 52 of the sensor. Each hall effect probe comprises three electrodes 521a, 521b, 521c, two of which are measurement electrodes 521a and 521b and one of which is a ground electrode 521 c. As shown in fig. 3, the three electrodes extend substantially axially and are adjacent to each other about the axis X of the machine.

As shown in fig. 4, the probes are orthogonally radially distributed around an angular sector of less than 180 °, advantageously less than 90 °.

The sensor carrier 54 is, for example, a plastic component in which three hall effect probes are housed. Sensor carrier 54 advantageously has the form of a crown about axis X, each of the three electrodes 521a, 521b, 521C being positioned facing the electronics.

As shown in fig. 3, a connector 530 extends from each hall effect probe so that each hall effect probe can be connected to the control electronics. The connection between the probe and the control board is provided by a track, allowing the control board to receive electrical signals emitted by the probe during rotation of the motor. The connection between the probe and the rail and the connection between the control board and the rail are provided, for example, by welding.

As shown in fig. 4, the portion 53 for electrically connecting the position sensor to the control electronics includes a track assembly connecting each of the three hall effect probes to the control electronics.

The detection part 52 of the position sensor, the sensor carrier 54 and the connection part 53 are advantageously overmoulded in a housing 55, for example made of plastic.

The housing 55 includes rails that electrically connect each probe to the control board. These tracks are for example overmoulded in the plastic housing 55 so that it is ensured that they are retained during use of the motor.

Fig. 5 shows the air flow due to the fan positioned on the rotor and to the paths advantageously created by the assembly of the different components. The air entering via the bearing upper opening makes it possible to cool the winding before exiting via the lateral openings.

The motor further comprises a temperature sensor 40, which is designed to measure the temperature of the motor.

The temperature sensor comprises a measuring probe 401 designed to locally measure the temperature, from which two connectors extend, said connectors making it possible to electrically connect the probe to the control electronics 38. Thus, the temperature sensor includes a ground connector 402c and a connector capable of applying a potential difference to the terminals of the probe 402 a.

The temperature sensor is advantageously a negative temperature coefficient sensor, for example. The temperature sensor is, for example, a negative temperature coefficient temperature sensor or a positive temperature coefficient temperature sensor.

The temperature sensor is supported by the position sensor.

The "temperature sensor supported by the position sensor" means that the temperature probe is contained in the housing of the position sensor or mounted on the surface of the housing of the position sensor, and the connection portion of the temperature sensor is shared with the connection portion of the position sensor. In particular, in the case where the temperature probe is contained in the housing of the position sensor, it is conceivable that the temperature probe and the hall effect probe are supported by a single sensor carrier or by two different sensor carriers. Where the temperature probe and the hall effect probe are supported by two different orthogonally radially adjacent sensor carriers, the housing may have two unconnected portions orthogonally radially adjacent about the axis of the motor, the two unconnected portions being connected by a common portion that houses at least the connected portions of the two sensors, as described and illustrated below.

Thus, the temperature sensor is positioned near the position sensor such that it is immersed in the same air flow, the temperature of which represents the motor temperature. By "near …" is meant that the distance between the sensors is small relative to the size of the motor, both axially about the axis X and in the orthogonal radial direction.

In the above embodiment, the sensing portion of the position sensor 52 and the measurement probe 401 of the temperature sensor are positioned orthogonally radially within an angular sector of less than 180 ° about the axis of the motor. As shown in fig. 3, the angular sector is advantageously less than 90 °. Thus, the temperature measured by the temperature sensor is substantially the same as the temperature of the motor air in the vicinity of the position sensor.

According to the first embodiment, the measurement probe of the temperature sensor 401 is supported by the detection portion of the position sensor 52.

The temperature probe is advantageously supported by the sensor carrier 54.

The three hall effect probes 520 and the temperature sensor 401 advantageously extend parallel and parallel to the axis of the motor.

The hall effect probe and the temperature probe are housed in the same sensor carrier. The sensor carrier has the form of, for example, a crown extending orthogonally radially around the axis of the motor. The probe is advantageously overmoulded in the sensor carrier.

According to this embodiment, the temperature probe 401 and the connectors 402a, 402c are also accommodated in the housing 55.

The temperature probe contained in the plastic thus makes it possible to obtain a reliable measurement of the temperature of the air in which it is located, without the plastic preventing its thermalization with the ambient air. Alternatively, a calibration thermal model may be used to calibrate the temperature measurements made at the temperature probe.

According to a variation of this embodiment, as described above, the housing 55 has an axial recess separating the hall effect probe and the temperature probe, as shown in fig. 4.

Thus, the casing 55 comprises two portions 55a and 55b, which are orthogonally radially adjacent about the axis X, each portion having substantially the form of a crown, the two adjacent portions being connected by a connecting portion 55 c.

According to the second embodiment shown in fig. 6, a probe 401 for measuring temperature is supported by the housing 55 at a portion of the housing that encloses the connection portion of the position sensor 53.

According to this second embodiment, the opening is advantageously provided in the housing 55 at a portion of the housing covering the connecting portion 53. This type of opening allows the passage of the electrical wires for the electrical connection of the probe of the temperature sensor 401, which is externally supported by the casing 55, the connectors 402a and 402c being connected to the control electronics 38 extending inside the casing.

The connectors of the temperature sensors 402a and 402c are thus accommodated in the housing 55.

According to the foregoing embodiment, the ground potentials of the position sensor and the temperature sensor are electrically connected to the ground of the control electronics 38. In fact, the ground potentials 521c and 402c are shared at the connection portion 53.

Claims (8)

1. A rotating electrical machine having an axis X, comprising:

-a shaft (13) supporting a rotor (12) surrounded by a stator (15) supported internally by a front bearing (16) and a rear bearing (17) connected to each other,

-an electronic assembly (36) mounted axially on the rear bearing (17) comprising power electronics (37) and control electronics (38),

a position sensor (50) for the rotor position, the sensor being associated with an object (51),

said target (51) being fixed on a target carrier (510) which is rotationally wedged on said rotor (12) and axially implanted between said rotor (12) and said rear bearing (17),

said position sensor (50) comprising a detection portion (52) designed to detect the passage of a magnetic target (51), and a portion (53) for electrically connecting said position sensor to said electronic device,

the sensing portion (52) of the position sensor is supported by the electronics assembly (36),

-a temperature sensor (40),

the temperature sensor comprising a measuring probe (401) designed to locally measure a temperature, and a portion (402) for electrically connecting the temperature sensor to the electronic device,

characterized in that said temperature sensor (40) is supported by said position sensor (50).

2. The electric machine according to claim 1, wherein the detection part (52) of the position sensor and the measuring probe of the temperature sensor (401) are positioned in an angular sector around the axis of the electric machine, said angular sector being less than 180 °, advantageously less than 90 °.

3. The electrical machine according to claim 1 or 2, wherein a measuring probe of the temperature sensor (401) is positioned axially between the rear bearing (17) and the electronic assembly (36).

4. The electric machine according to any of claims 1 to 3, wherein a measuring probe of the temperature sensor (401) is supported by a detecting portion (52) of the position sensor.

5. The electric machine according to claim 4, comprising a sensor carrier (54), the detection portion (52) of the position sensor and the measurement probe of the temperature sensor (401) being enclosed in the sensor carrier (54).

6. The electric machine according to claim 5, wherein the sensor carrier (54) comprises at least one first portion (54a) and one distinct second portion (54b), the first and second portions (54b) being circumferentially adjacent around the axis of the electric machine and being interconnected by a third portion (54c), the first portion (54a) overmoulding the sensing portion (52) of the position sensor and the second portion (54b) overmoulding the measuring probe of the temperature sensor (401).

7. The electric machine according to any of claims 1 to 3, wherein a measuring probe of the temperature sensor (401) is supported by a connecting portion (53) of the position sensor.

8. The electric machine as claimed in any of the preceding claims, wherein the connection portions of the temperature sensor (402) and the position sensor (53) have a common ground, the common ground being electrically connected to a ground of the control electronics (38).

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