WO2020108686A1

WO2020108686A1 - Actuator and method for assembling an actuator

Info

Publication number: WO2020108686A1
Application number: PCT/DE2019/100929
Authority: WO
Inventors: Dominik Kohlhaas; Markus Dietrich
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2018-11-29
Filing date: 2019-10-29
Publication date: 2020-06-04
Also published as: CN113169605A; DE102018130270A1

Abstract

The present invention relates to a rotor (1) for a motor vehicle actuator comprising an inner rotor ring (2) and, attached thereto, rotor segments (3), which are separated from one another in the circumferential direction by gaps (4), wherein the gaps (4) are made of such a size as to each receive a magnet (5) and are configured such that, during operation, the magnets (5) point substantially in a radial direction in the manner of spokes, wherein at least one of the rotor segments (3) is attached to the inner rotor ring (2) by way of an arm (6), which has such material properties and deformation characteristics that, after lengthening (ΔL) as a result of a positional displacement (ΔD) of the rotor segment (3) radially outwards, it reverts to its original form when the force responsible for the positional change no longer occurs. The present invention also relates to an actuator or an electric machine having such a rotor (1) and also to an associated assembly method.

Description

Actuator and method for assembling an actuator

The present disclosure relates to a rotor for a motor vehicle actuator with a rotor inner ring and attached rotor segments, which are separated from one another in the circumferential direction by gaps, the gaps being dimensioned and equipped for receiving one magnet each, so that the magnets are in operation in the manner of a spoke Point essentially in the radial direction. Furthermore, the present disclosure relates to an actuator or an electric machine with such a rotor and a method for assembling them.

Motor vehicle actuators, in particular brushless DC motors, are to be operated in liquids (for example an oil or a brake fluid). In motor vehicle actuators in a spoke arrangement, magnets are arranged in the manner of a spoke in a laminated core (rotor or rotor part). According to the current state of the art who inserted the magnets into the laminated cores during the manufacture of such an actuator, disadvantageously the sharp-edged corners of the laminations can lead to damage to the protective layer on the magnet. As a result, it is accepted that contact with liquids such as oil or brake fluid can corrode or powder the magnets at these points. This can impair the function of the engine or even destroy the engine completely.

The object of the invention is therefore to provide a rotor which avoids or at least reduces disadvantages of the prior art. In particular, it is an object of the invention to enable reliable, simple and damage-free attachment of the magnets to the rotor, in particular with regard to the coating of the magnets.

The object on which the invention is based is achieved in the case of a generic rotor in that at least one of the rotor segments is attached to the rotor inner ring via a web, the web having material properties and deformation properties such that after an elongation due to a position displacement of the rotor segment radially outside returns to its original shape when a force responsible for the position shift is lost. In particular the bridge has elastic properties. Since the gap becomes wider on both sides of the rotor segment when a web and the associated positional displacement, i.e. the actuation path of the rotor segment, are elongated, it is possible in a simple, reliable manner to insert the corresponding magnets into the column without contact and then, when the force is lost, between the gaps pinch adjacent rotor segments, thereby avoiding the problems of the prior art described above.

The web advantageously has a single or multiple curved shape or configuration, for example S-shaped or Z-like. This is particularly advantageous compared to an alternative design with non-curved webs, which can ultimately be elongated due to their material elasticity or stretch, since greater elongation can be achieved with comparatively little force.

According to one aspect of the invention, each rotor segment can be connected to the one-piece or multi-piece rotor inner ring via a web. In addition, all the webs, or at least every second web seen in the circumferential direction, which have the same properties, in particular with regard to material properties, material properties and / or reset behavior. If only every second web has the same properties, a stiffer structure and greater strength of the rotor can be achieved. Otherwise, if all the webs have the same properties, a greater widening of the gaps is achieved during assembly with the same actuation path, which makes it easier to use the magnets without contact.

It has proven to be useful that one of the rotor segments or all of the rotor segments has a recess for inserting a tool, such as a dome, in order to introduce a force and to force a radial displacement of the rotor segment or the rotor segments. As a result, a simply designed tool can easily and securely engage in the rotor segments in the course of an assembly process in order to apply the force for shifting the position, no outwardly protruding structures being necessary. According to a preferred embodiment of the invention, all webs have a constant thickness. This can ensure that the elongation behavior of each web can be calculated easily and evenly and that manufacturing costs are also reduced.

It is also advantageous if the recess has a shape approximating an ellipse or an egg. Alternatively, the recess can also have an angular shape, for example the shape of a rectangle or a triangle. Simply put, it is preferred if the recess has a non-circular shape. Mathematically speaking, it is advantageous if the recess has the shape of a flat, geometric figure in which at least two points of the figure have a different distance from the center of the figure. This makes it possible to use and / or anchor a tool to each rotor segment during an assembly process in a specific position, in particular secured against rotation.

Appropriately, on one side or on both sides in the circumferential direction, at least every second rotor segment, preferably each rotor segment, has a projection extending in the circumferential direction on its radially outer edges. This is advantageous because the magnets are redundant, i.e. that is, in addition to a friction-based clamping between the rotor segments, can be held positively in the direction of the radially outer side.

It has also proven to be advantageous to design the gaps and recesses in such a way that they are shaped, arranged and dimensioned as a function of a magnetic flux when the rotor is in operation, in order to be able to operate the rotor in the most energy-efficient manner. In particular, an elliptical shape of the recess has advantageously proven to optimally direct the magnetic flux.

The object underlying the invention is further achieved by an actuator or an electric machine for a motor vehicle with a rotor as described above, wherein magnets are or are inserted between the rotor segments. It has proven useful that the magnets are covered with a protective layer or stratification are covered. This protects the magnets from corroding, powdering or other wear.

According to a preferred aspect of the invention, a liquid, such as oil or brake fluid, can be present between the magnet, the rotor segments and the rotor inner ring during operation. This advantageously enables maximum flexibility with regard to an installation situation of the rotor, in particular with regard to cooling and lubrication.

In addition, the object of the invention is achieved by a method for assembling an actuator or an electric machine with a rotor described above, wherein a tool is inserted into the recess of a rotor segment, then an external force is applied and the rotor segment is shifted position in the radial direction , then a mag net is inserted into the gap next to the rotor segment, the external force subsequently disappearing and then the elongated web, which acts, for example, on the radial inside of the rotor segment, reduces the gap again and clamps the magnet between two adjacent rotor segments by he moves the rotor segment back to its (almost) original position or withdraws it.

In other words, the object is achieved in that elastic webs are provided between individual (rotor) segments and a (rotor) inner ring, which can be expanded in the radial direction. The webs are stretched by an external force. Due to the expansion in the radial direction, gaps (between the segments, alternatively also referred to as recesses / intermediate space / space) for the magnets are larger and the magnets can be used without damage. If the external force is removed, the webs return to their original shape and clamp the magnets. An inner sheet metal ring (inner rotor ring), in which, for example, a shaft is pressed in, is connected to the individual rotor segments via the deformable webs (designed as an S-lay in one embodiment). The magnets are inserted in the space between the segments. Recesses in the sheet metal segments can be made as desired, taking into account the magnetic flux. The procedure for inserting the magnets is as follows: The (rotor or) sheet metal segments are pulled radially outwards (by a tool) external force). The elastic connections between the segments and the inner ring are stretched. Due to the radial displacements, spaces (gaps) for inserting the magnets become larger. The magnets can now be used in the now larger windows (gaps / rooms) almost without touching and damaging the coating. If the external force is reduced or completely removed, the elastic webs pull the segments radially inward again to their original position. The sheet metal segments lay against the magnets used and fix them in place.

The webs between the individual segments and the inner ring can be designed in different shapes. In addition to the S-shaped webs mentioned above, e.g. curved bars possible. It is important that the ridges are only elastically deformed in the event of a radial displacement of the rotor segments, since the segments no longer return to their original shape when the radial force is removed when the radial force is removed.

The invention is explained in more detail below with the aid of figures, in which a preferred embodiment is shown.

1 is a partial top view of a rotor according to the invention.

Fig. 2 represents an operation of the rotor.

3 illustrates mounting magnets on the rotor.

Fig. 4 shows the rotor with mounted magnets.

The figures are merely schematic in nature and are used to understand the invention. Furthermore, the same reference numerals are used below for the same or corresponding components. 1, like FIGS. 2, 3 and 4, is a partial top view of an embodiment of the rotor 1 according to the invention. The rotor 1 has an inner rotor ring 2 which forms a shaft seat on an inner peripheral surface for mounting on an input or output shaft. A number of rotor segments 3 are separated from one another by gaps 4 or spaces which are provided for inserting magnets 5, the rotor segments 3 being elastically connected to the inner ring 2 of the rotor by means of webs 6. The webs 6 are designed as S-shaped curved springs.

Centrally in the rotor segments 3, elliptical or egg-shaped recesses 7 are provided as tool holders, in which a tool can be used to assemble the rotor 1. A corresponding assembly process is described in more detail later with reference to FIGS. 3 and 4. Furthermore, the rotor segments 3 are viewed in the rotor axial direction (that is to say in the plan view shown here) essentially in the form of a trapezoid in such a way that the gaps 4 or (interstices) are rectangular, or in other words that adjacent side walls of the rotor segments in the circumferential direction 3 are parallel to each other. At radially outer edges of the rotor segments 3, d. that is, at transitions between circumferentially aligned side walls 8 and an outer surface 9 of each rotor segment 3 projecting, preferably rounded projections 10 are arranged in the circumferential direction. The outer surfaces 9 of the rotor segments 3 are part of an outer peripheral surface of the rotor 1.

2 illustrates a functional principle of the rotor 1 according to the invention. Exactly he expressed two views of the rotor 1 are superimposed in this representation. A ne first view (dashed lines) shows the rotor 1 in its normal state, in which the rotor segments 3 are each arranged in their starting position (at their original positions), in which the webs 6 are relaxed or not elongated. A second view (solid lines) shows the rotor 1 in a Montagezu stand, in which the rotor segments 3 are each in their mounting position. The webs 6 are elongated in the assembled state compared to the normal state by a specific length AL and the rotor segments 3 are each radially outwardly displaced by a corresponding distance AD. Due to the positioning of the rotor segments 3 radially outwards, the gaps 4 between the rotor segments 3 are widened by a certain width AS in the assembled state. 3 shows an assembly process of the rotor according to the invention, in which the magnets 5 are inserted into the column 4 between the rotor segments 3. During such an assembly process, at least one tool, for example one or more mandrels, is inserted into one or, as shown here, several elliptical or egg-shaped recesses 7 of the rotor segments 3, and the tool exerts a radially outward external force on the rotor segments 3 applied, which is opposite to an elastic restoring force of the webs 6 and through which the rotor segments 3 are displaced radially outward. The assembly state shown here is thereby achieved. Since the column 4 between the Ro torsegmenten 3 are widened by the width AS, these are now wider than the Mag nete 5, which thus, as shown here, can be used in the column 4 without having sharp edges or the like of the rotor segments in To come into contact or slide along it.

Fig. 4 shows a rotor in which the magnets 5 are assembled. That is, after the insertion of the magnets 5 shown in FIG. 3, the external force was reduced or canceled and the tool was removed if necessary, whereupon the webs 6 (again) due to their spring force or elastic material and deformation properties returned to their starting position and thereby the rotor segments 3 (almost) have retracted into their starting position. As a result, the magnets 5 are each with opposite side walls 8 of two rotor segments 3 in contact and clamped between them. In this starting position, the magnets are arranged radially within the projections 10 in such a way that they partially protrude beyond the magnets in the circumferential direction and thereby limit their position in the radially outer direction. Reference list

AL elongation of a web

AD position shift of a rotor segment

AS widening of a gap

1 rotor

2 inner rotor ring

3 rotor segment

4 gap or (space)

5 magnet

6 bridge

7 recess

8 side wall

9 outer surface

10 head start

Claims

1.Rotor (1) for a motor vehicle actuator with a rotor inner ring (2) and rotor segments (3) attached to it, which are separated from one another in the circumferential direction by gaps (4), the gaps (4) for receiving each magnet (5 ) are dimensioned and equipped so that during operation the magnets (5) point essentially radially in the manner of spokes, characterized in that at least one of the rotor segments (3) is attached to the rotor inner ring (2) via a web (6) which has such material properties and has deformation properties that it returns to its original shape after elongation (AL) due to a positional shift of the rotor segment (3) radially outwards when the force responsible for the positional shift (AD) ceases to exist.

2. Rotor (1) according to claim 1, characterized in that the web (6) has elastic properties.

3. Rotor (1) according to one of claims 1 and 2, characterized in that the web (6) has a curved shape.

4. Rotor (1) according to one of the preceding claims, characterized in that each rotor segment (3) via a web (6) with the one-piece or multi-piece rotor inner ring (2) is connected.

5. Rotor (1) according to any one of the preceding claims, characterized in that all the webs (6) or at least in the circumferential direction, every second web (6) have or have the same properties.

6. rotor (1) according to any one of the preceding claims, characterized in that one of the rotor segments (3) or all rotor segments (3) a Ausspa- tion (7) for inserting a tool or has to introduce force and to overcome a radial displacement of the rotor segment (3) or the rotor segments (3).

7. rotor (1) according to any one of the preceding claims, characterized in that all the webs (6) have a constant thickness.

8. Rotor (1) according to one of claims 6 and 7, characterized in that the recess (7) has a shape approximating an ellipse or a rectangular shape or a triangular shape.

9. Actuator or electric machine for a motor vehicle with a rotor (1) according to one of claims 1 to 8, wherein magnets (5) are inserted between the rotor segments (3).

10. A method for assembling an actuator or an electric machine with a rotor (1) according to one of claims 1 to 8, wherein a tool is inserted into the recess (7) of a rotor segment (3), then an external force is applied and that The rotor segment (3) is shifted in the radial direction, then a magnet (5) is used in the gap (4) next to the rotor segment (3), the external force subsequently disappearing and the elongated web (6) thereby closing the gap (4 ) reduced again and the magnet (5) clamped between two adjacent rotor segments (3) by moving the relocated rotor segment (3) back to its original position.