EP2769460A2

EP2769460A2 - Method for producing a bldc motor

Info

Publication number: EP2769460A2
Application number: EP12784498.3A
Authority: EP
Inventors: Thomas Hannewald
Original assignee: Continental Automotive GmbH
Current assignee: Continental Automotive GmbH
Priority date: 2011-10-18
Filing date: 2012-10-15
Publication date: 2014-08-27
Also published as: WO2013057064A3; CN103875167B; US9356496B2; US20140259637A1; DE102011084702A1; CN103875167A; WO2013057064A2

Abstract

A stator with coils (3) associated with at least two different phases is provided. A rotor comprising a shaft (5) and rotor magnets (7) arranged on the latter is provided. The rotor is arranged in a cavity of the stator. The shaft (5) is mounted using a first bearing (23) which is arranged between the shaft (5) and the stator. A carrier element (13) is provided, the latter having a recess which is penetrated by the shaft (5) and has a surface which is formed orthogonally with respect to the shaft (5) and on which a plurality of Hall sensors (15) are arranged with an angular offset to one another with respect to the centre point of the shaft (5). The carrier element (13) is arranged such that it is fixed with respect to the stator. A permanent magnet wheel (9) with transducer magnets (11) arranged with an angular offset is prefixed on the shaft (5). The shaft (5) is caused to rotate. Measurement signal profiles of the Hall sensors (15) are recorded and measurement signal profiles which are representative of voltages induced in the coils (3) on the basis of the rotor magnets (7) are recorded. An adjustment angle for the permanent magnet wheel (9) is determined on the basis of the measurement signal profiles of the Hall sensors (15) and the temporally correlating measurement signal profiles which are representative of voltages induced in the coils (3). The permanent magnet wheel (9) is rotated with respect to the shaft (5) according to the adjustment angle determined. The permanent magnet wheel (9) is then fixed on the shaft (5).

Description

description

Method of making a BLDC motor

Electric motors regularly have a rotor and a stator. Particularly in the field of vehicle technology, so-called brushless DC motors, which are also referred to as BLDC motors, are becoming increasingly popular. Such BLDC motors are synchronous machines driven by direct current and having electrical commutation rather than mechanical commutators and brushes.

In this way, a lower friction is guaranteed compared to motors with commutators and brushes, which thus has a positive effect on the efficiency. In addition, a so-called brush fire can be avoided, which on the one hand leads to electrical losses and on the other hand also contributes to increased mechanical wear.

The rotor of the BLDC motor has rotor magnets, which are designed as permanent magnets. Due to the fact that there are no windings of coils on the rotor, they are not exposed to centrifugal forces. Further, windings are arranged only on the stator, with the result that for cooling no air cooling in the region of the rotor is required and thus the inner region, in particular the region of the rotor in which the rotor magnets are arranged, can be encapsulated outwardly and so can be protected from dirt particles and other external particles.

The object underlying the invention is to provide a method of manufacturing a BLDC motor that contributes to high efficiency during operation of the BLDC motor thus produced. The object is solved by the features of the independent claims. Advantageous embodiments are characterized in the subclaims. According to a first aspect, the invention is characterized by a method of manufacturing a BLDC motor in which a stator is provided with coils associated with at least two different phases. A rotor is provided which comprises a shaft and comprises rotor magnets arranged on the shaft. The rotor is arranged in a cavity of the stator. The shaft is supported by means of a first bearing, which is arranged between the shaft and the stator. A carrier element is provided which has a recess which is penetrated by the shaft and an orthogonal to the shaft, ie in particular their

Center axis, has trained surface on which a plurality of Hall sensors are angularly offset with respect to the center of the shaft to each other. The carrier element is arranged fixed to the stator.

A permanent magnet wheel with encoder magnets arranged angularly offset is prefixed on the shaft, specifically on a side of the carrier element facing away from the rotor magnet. The permanent magnet wheel is axially spaced from the carrier element in such a way that upon a rotational movement of the shaft caused by the magnetic fields of the transmitter magnets correspondingly desired measurement signal profiles in the Hall sensors are produced. The shaft is set in a rotary motion and measuring signal characteristics of the Hall sensors are detected. Furthermore, measurement signal waveforms are also detected which are representative of voltages induced in the coils as a function of the rotor magnets, that is to say of the magnetic fields generated by them. Dependent on the measurement signal profiles of the Hall sensors and the time-correlated measuring signal curves, which are representative of voltages induced in the coils, becomes Adjustment angle for the magnetic wheel determined. The permanent magnet wheel is rotated in accordance with the determined adjustment angle with respect to the shaft and then the permanent magnet wheel is fixed on the shaft.

In this way, a contribution can be made in a particularly effective and simple manner so that the relative position of the rotor to the stator can be determined very precisely in a later operation of the BLDC motor, in particular with regard to the relative position of the respective coils on the stator and the respective rotor magnet on the rotor. In this way, a control of the coils which is dependent on the respective measurement signal profiles of the Hall sensors can then be particularly precise and thus an important contribution can be made to a high efficiency in the operation of the BLDC motor.

According to a second aspect, the invention is characterized by a method of manufacturing a BLDC motor in which a stator is provided with coils associated with at least two different phases. A rotor is provided which comprises a shaft and comprises rotor magnets arranged on the shaft. The rotor is arranged in a cavity of the stator. The shaft is supported by means of a first bearing, which is arranged between the shaft and the stator. A carrier element is provided, which has a recess which is penetrated by the shaft and has a surface orthogonal to the shaft, thus in particular its center axis, on which several Hall sensors are arranged angularly offset with respect to the center of the shaft relative to one another. The carrier element is arranged fixed to the stator.

The shaft is set in a rotational movement and temporally correlated therewith measuring signal waveforms are detected, which are representative of voltages induced in the coils. dependent on the rotor magnets and in particular on the magnetic fields caused by them.

Upon detection of a reference angular position of the shaft relative to the stator, which is detected as a function of the measurement waveforms representative of voltages induced in the coils, the shaft is held in the detected reference angular position. Subsequently, a permanent magnet with angularly arranged arranged encoder magnet is applied to the shaft, on a side facing away from the rotor magnet side of the support member. In principle, the permanent magnet wheel can also be applied to the shaft even before the displacement of the shaft in a rotational movement for detecting the reference angular position.

The permanent magnet wheel is rotated with respect to the shaft until a predetermined condition is met, which depends on a detected measurement waveform of the Hall sensors during rotation, during this rotation, the shaft is still held in the reference angular position. To

Meeting the predetermined condition, the permanent magnet is fixed on the shaft and lifted the holding of the shaft in the reference angular position. The advantages of the second aspect basically correspond to those of the first aspect.

According to an advantageous embodiment, the fulfillment of the predetermined condition depends on the measurement signal characteristic of at least one of the Hall sensors representing a switching point. The respective switching point correlates in particular with pole changes of the magnetic wheel rotating relative to the carrier element. In this case, the respective switching point may relate to one of the Hall sensors or also relate to the switching points of several Hall sensors and have a predetermined interaction of the respective switching points to the condition. According to a further advantageous embodiment, the fixing of the permanent magnet wheel on the shaft comprises a laser welding. In this way, the permanent magnet can be FITS precise and easily fixed in the respective position, and indeed permanently fixed.

According to a further advantageous embodiment, after fixing the permanent magnet wheel, a bearing plate is mounted with a bearing and the shaft is mounted on the bearing. The bearing is arranged on a side facing away from the rotor magnet of the permanent magnet wheel. In this way, then before fixing the permanent magnet wheel on the shaft this can be easily accessible for appropriate tools and then the shaft can be stored reliably and optionally carried out at the same time a corresponding seal of the cavity of the stator.

Embodiments of the invention are explained in more detail below with reference to the schematic drawings. Show it:

FIG. 1 shows a BLDC motor that is finished,

Figure 2 is a plan view of a permanent magnet of

BLDC motor according to FIG. 1,

3 shows a first flow chart of a method in connection with a production of the BLDC motor and

FIG. 4 shows a second flow chart in connection with FIG

Making the BLDC motor.

Elements of the same construction or function are identified across the figures with the same reference numerals.

A BLDC motor has a stator with a stator housing 1 (see FIG. 1) in which coils 3 are arranged. The coils 3 are associated with at least two different phases, for example, three different phases. Furthermore, the BLDC motor comprises a rotor which comprises a shaft 5 and rotor magnets 7 arranged thereon. The rotor magnets 7 may, for example, be glued to the shaft and / or fixed on it by means of a cage, for example a block cage. The rotor is arranged in a cavity of the stator. The shaft 5 is supported by means of a first bearing 23, which is arranged between the shaft 5 and the stator, in particular the stator housing 1. The first bearing 23 is preferably arranged in a first end region of the shaft 5.

Furthermore, a carrier element 13 is provided, which has a recess which is penetrated by the shaft 5 and has an orthogonal to the shaft 5, in particular its central axis, formed surface on which a plurality of Hall sensors 15, 17, 19, 21 (Figure 2) angularly offset with respect to the center of the shaft 5 to each other. The carrier element 13 is arranged fixed to the stator. The carrier element preferably comprises a printed circuit board with electrical conductor tracks and / or electrical or electronic components and / or sensors. The sensors are designed, for example, as the Hall sensors 15, 17, 19, 21.

Further, on a side facing away from the rotor magnet 7 of the support member 13, a permanent magnet 9 is arranged, which is fixed in the finished manufactured BLDC motor on the shaft 5. The permanent magnet 9 has angularly arranged encoder magnets 11 (see FIG. 2), which are designed as permanent magnets, and is arranged axially spaced from the carrier element 13 such that the magnetic fields generated by the transmitter magnets 11 are applied to the Hall sensors 15, 17 in the desired manner , 19, 21 act on a relative rotational movement between the permanent magnet 9 and the carrier element 13.

In FIG. 2, only one encoder magnet is provided with the reference numeral 11. However, the permanent magnet 9 has preferably a plurality of encoder magnets 11, as is also more apparent from the figure 2.

The Hall sensors 15, 17, 19, 21 are shown in FIG. 2 in their position which they have relative to one another on the carrier element 13, without the carrier element 13 being illustrated in FIG. Their position in the radial direction starting from the center of the shaft 5 with respect to the permanent magnet wheel 9 can be seen in FIG. 2, whereby, of course, the representation in FIG. 2 merely represents a position which the permanent magnet wheel 9 places relative to that on the carrier element 13 Hall sensors 15, 17, 19, 21 occupies. The carrier element 13 has power switches, by means of which a power supply to the coil 3 is controlled. The circuit breakers are in particular switched as a function of characteristic measurement signal profiles of their respective associated Hall sensors 15, 17, 19 and thus cause a power supply or current interruption to the respective coils and thus with respect to the respective phases. The characteristic measuring signal course is in particular a strong change of the measuring signal, which is also referred to as a switching point, which is caused by a strong change in the magnetic field passing through the Hall sensor 15, 17, 19.

Furthermore, the BLDC motor has a bearing plate 25, with a second bearing 27, in which the shaft 5 is also mounted. The bearing plate 25 supports the shaft 5 on a side facing away from the rotor magnet 7 side compared to the first

Bearing 23. The second bearing 27 is further arranged on a side facing away from the rotor magnet 7 side of the permanent magnet wheel 9. Preferably, the end shield 25 also includes a seal which seals the cavity of the stator.

Furthermore, the BLDC motor has a plug element 29, which for electrically contacting the BLDC motor with a external control and supply unit is provided and which has contacts which are electrically conductively coupled to the carrier element 13. According to a first embodiment of manufacturing the BLDC motor, the stator is provided with the coils 3 in a step Sl. Furthermore, the rotor is provided with the shaft 5 and the rotor magnet 7 arranged thereon. In this case, the rotor is arranged in the cavity of the stator, and the shaft 5 is supported by means of the first bearing 23.

Further, in the step Sl, the support member 13 is provided, already in its mounted state in the stator. In a step S3, the permanent magnet 9 is pre-fixed on the shaft 5. It is thus mounted on the shaft 5, that it moves with a rotation of the shaft 5 with this without a relative movement to execute this but without being firmly fixed, which gives the possibility, in particular by means of a suitable tool

Permanent magnet 9 still to rotate relative to the shaft 5.

In a step S5, the shaft 5 is set in a rotational movement, and measurement signal waveforms of the Hall sensors 15, 17, 19, 21 are detected. Furthermore, measured signal waveforms which are representative of voltages induced in the coils 3 as a function of the rotor magnets 7 and their magnetic fields are also detected in a time-correlated manner. This can be done, for example, by appropriately detecting the current in the coils 3 caused by the induced voltages.

The displacement of the shaft 5 in the rotational movement takes place by means of an external drive provided for this purpose, which acts on the shaft 5. Furthermore, during the execution of step S5, the shaft is preferably also supported by means of an auxiliary bearing which is mounted on a rotor magnet 7. less than the permanent magnet 9 side facing away from the shaft 5 acts.

In a step S7, an adjustment angle for the permanent magnet wheel 9 is determined as a function of the measured signal profiles of the Hall sensors 15, 17, 19, 21 and the time-correlated measuring signal curves, which are representative of voltages induced in the coils 3. In this context, the knowledge is used that the measurement signal curves which are representative of voltages induced in the coils are characteristic of the respective angular position of the stator to the rotor and the temporally associated measurement signal profiles of the Hall sensors are in turn representative of the respective angular position between the permanent magnet 9 and the stator. The adjustment angle is preferably determined in this context such that the measurement signal profiles of the Hall sensors 15, 17, 19, 21 in particular with regard to their switching points have the respective desired reference to the respective relative angular position between the stator and the rotor.

In a step S9, the permanent magnet wheel 9 is rotated with respect to the shaft 5 in accordance with the determined adjustment angle.

In a step Sil, the permanent magnet wheel 9 is then fixed on the shaft 5. This is preferably done for example by means of laser welding. Subsequently, in a step S12, the first

Removed auxiliary bearing and the external drive and then mounted the bearing plate 25.

A second exemplary embodiment for producing the BLDC motor is explained in more detail with reference to the flowchart of FIG. The step S13 corresponds to the step S1. In a step S15, the shaft 5 is rotated. sets and thereby detects measurement signal waveforms that are representative of induced in the coil 3 voltages. The displacement of the shaft 5 into a rotational movement takes place in step S15 by means of a drive external to the BLDC motor, which is coupled to the shaft 5 for these purposes. Furthermore, in carrying out the steps, an auxiliary bearing is preferably provided according to the procedure according to FIG. 3.

In a step S17, upon detection of a reference angle position of the shaft 5 relative to the stator, which is detected as a function of measuring signal curves which are representative of voltages induced in the coils 3, the shaft 5 is then held in this detected reference position, namely via the processing of step S17 addition.

In a step S19, the permanent magnet wheel 9 is applied to the shaft 5. In a step S21, the permanent magnet wheel 9 is rotated relative to the shaft 5 until a predetermined condition is met, which depends on the detected measurement signal profile of the Hall sensors 15, 17, 19, 21 during rotation. In this case, the fulfillment of the predetermined condition preferably depends on the measurement signal profile of at least one of the Hall sensors representing the switching point.

The statements made with regard to the exemplary embodiment according to FIG. 3 are basically also applicable with regard to the exemplary embodiment according to FIG. In a step S23, the permanent magnet 9 is fixed on the shaft 5, for example also by means of laser welding. In a step S25, the holding of the shaft in the reference angular position is then canceled. In a step S27, after removing the external drive and the auxiliary bearing, the end shield is mounted. With regard to the assignment of the relative angular position of the rotor to the stator, a zero crossing of the respective induced voltage can be correspondingly evaluated in the production, in particular with regard to the measurement signal profiles which are representative of voltages induced in the coils 3. In addition, in the context of producing a corresponding adjustment of the axial distance between the permanent magnet 9 and the carrier element 13 take place. By the procedure described, a contribution can be made for very low manufacturing tolerances.

Claims

claims

Method for producing a BLDC motor, in which

providing a stator with coils (3) associated with at least two different phases,

a rotor is provided comprising a shaft (5) and rotor magnets (7) arranged thereon, wherein the rotor is arranged in a cavity of the stator, and the shaft (5) is supported by means of a first bearing (23) which extends between the rotor Shaft (5) and the stator is arranged,

- A support member (13) is provided which has a recess which is penetrated by the shaft (5) and has an orthogonal to the shaft (5) formed surface on which a plurality of Hall sensors (15, 17, 19, 21) angularly offset with respect to the center of the shaft (5) are arranged to each other, wherein the carrier element (13) is arranged fixed to the stator,

a permanent magnet wheel (9) is pre-fixed on the shaft (5) with encoder magnets (11) arranged angularly offset, on a side of the carrier element (13) remote from the rotor magnet (7),

- The shaft (5) is set in a rotational movement and measuring signal waveforms of the Hall sensors (15, 17, 19, 21) are detected and measuring waveforms are detected, which are representative of in the coils depending on the rotor magnet (7) induced voltages,

depending on the measuring signal profiles of the Hall sensors (15, 17, 19, 21) and the time-correlated measuring signal curves which are representative of voltages induced in the coils (3), an adjustment angle for the permanent magnet wheel (9) is determined;

- The permanent magnet (9) is rotated according to the determined adjustment angle with respect to the shaft (5) and - The permanent magnet (9) on the shaft (5) is fixed.

Method for producing a BLDC motor, in which

a rotor is provided comprising a shaft (5) and rotor magnets (7) arranged thereon, wherein the rotor is arranged in a cavity of the stator and the shaft (5) is supported by means of a first bearing (23) arranged between the shaft (5) and the stator is arranged,

- The shaft (5) is set in a rotational movement and thereby measuring signal waveforms are detected, which are representative of in the coils (3) induced voltages depending on the rotor magnet (7),

upon detection of a reference angular position of the shaft (5) relative to the stator, which is detected as a function of the measuring signal curves which are representative of voltages induced in the coils (3), the shaft (5) being held in the reference angular position,

a permanent magnet wheel (9) with angularly arranged transmitter magnets (11) is applied to the shaft (5), specifically on a side of the carrier element (13) facing away from the rotor magnet (7),

- The permanent magnet wheel (9) with respect to the shaft (5) is rotated until a predetermined condition is met, which depends on a detected Meßsignal- course of the Hall sensors (15, 17, 19, 21) during rotation,

- The permanent magnet wheel (9) on the shaft (5) is fixed and

- The holding of the shaft (5) is canceled in the reference angular position.

Method according to Claim 2, in which the fulfillment of the predetermined condition depends on the measurement signal profile of at least one of the Hall sensors (15, 17, 19, 21) being dependent on the measurement signal characteristic of at least one of the Hall sensors (15, 17, 19, 21) represents a switching point.

Method according to one of the preceding claims, wherein the fixing of the permanent magnet wheel (9) on the shaft (5) comprises a laser welding.

Method according to one of the preceding claims, wherein after fixing the permanent magnet wheel (9) a bearing plate (25) is mounted with a bearing and the shaft (5) is mounted on the bearing, wherein the bearing facing away from the rotor magnet (7) Side of the permanent magnet wheel (9) is arranged.