DE102019216803A1 - Electric motor for a gear actuator - Google Patents

Abstract

Disclosed is an electric motor, in particular for an actuator, having a stator with at least one stator coil and having a rotor, the rotor being rotationally symmetrical and having at least one permanent magnet for interacting with the at least one stator coil, the rotor having a shaft for driving a Transmission is connected, wherein the stator has a coil section with the at least one stator coil and a compensation section, wherein the coil section and the compensation section are designed as circular ring segments and are axially spaced apart by spacers. An actuator and an expansion valve are also disclosed.

Description

The invention relates to an electric motor, in particular for an actuator, having a stator with at least one stator coil and having a rotor. The invention also relates to an actuator.

State of the art

Electromechanically driven actuators are used in various technical areas. For example, actuators are used in vehicles for adjusting exterior mirrors, for operating a headlight range control, for adjusting seats or for controlling throttle valves. In the case of the known actuators, commercially available electric motors with a gear are used. Such an arrangement of the electric motor with a transmission can, however, have disadvantageous effects with regard to the installation space requirement and thus also to the weight of the actuator.

In the case of electrically powered vehicles in particular, the available electrical energy of a traction battery is limited. Therefore, the lowest possible vehicle mass and a compact design of the components used are essential for an increased range of the electrically powered vehicle. The actuators currently used in vehicles are inadequate in terms of energy efficiency and can have a detrimental effect on the vehicle mass.

Disclosure of the invention

The object on which the invention is based can be seen in proposing an electric motor and an actuator which have a reduced mass and a reduced space requirement.

This object is achieved by means of the respective subject matter of the independent claims. Advantageous refinements of the invention are the subject matter of the respective dependent subclaims.

According to one aspect of the invention, an electric motor, in particular for an actuator, is provided. The electric motor has a stator with at least one stator coil and a rotor. The rotor is preferably designed to be rotationally symmetrical and has at least one permanent magnet for interacting with the at least one stator coil. The at least one stator coil can act on the at least one permanent magnet of the rotor in a radial direction or an axial direction, for example, in order to set the rotor in rotation or to maintain a rotation of the rotor.

The rotor is connected to a shaft for driving a gearbox. At the same time, the shaft forms an axis of rotation of the rotor. Starting from the axis of rotation of the rotor, the axial direction runs parallel to or congruent with the axis of rotation. The radial direction extends perpendicularly from the axis of rotation.

The stator preferably has a coil section with the at least one stator coil and a compensating section, the coil section and the compensating section being designed as circular ring segments and being axially spaced from one another by spacers. The annulus segment of the coil section can, for example, encompass an angular range of 140 ° of the stator. The compensation section can take up an angular range of 220 °, as a result of which the compensation section and the coil section together form a circular ring segment of 360 °.

The coil section and the compensation section thus form an axially graduated circular ring. As a result of the gradation, a first receiving space for the at least one coil is formed axially between the rotor and the coil section. In this case, the gradation forms a second receiving space or a free space for receiving a gear or parts of a gear on a side of the compensating section axially facing away from the rotor.

Due to the axially stepped design of the stator, a particularly compact design of the electric motor and an actuator with such an electric motor can be realized. In particular, through the gradation of at least two circular ring segments, the stator can provide receiving space for stator coils and for a gear, so that a gear can be arranged axially below the compensating section. As a result, a space usually taken up by the electric motor can be partially used by a transmission.

The compensation section can be designed without stator coils. By means of such a one-sided or regional coil arrangement, the stator coils are mainly positioned in the annulus segment of the stator configured as a coil section. Such a reduction in the number of stator coils leads to a weight reduction and a saving in installation space. Furthermore, the compensation section can have smaller dimensions and a reduced material thickness than the coil section in order to enable a further reduction in weight.

The electric motor can preferably be used to drive transmissions and components be applicable. For example, the electric motor can be used for valve control and valve control. In principle, the electric motor can be used with any type of actuator.

According to one embodiment, stator structures are arranged on the coil section, which stator structures extend axially from the coil section. At least one stator structure is preferably designed as a stator core for the at least one stator coil. The stator structures can extend parallel to the spacers and parallel to the axis of rotation of the electric motor and can be fastened to the coil section or configured integrally with the coil section. The stator structures can be shaped as columns which have a uniform or non-uniform cross section. For example, the stator structures can have a rectangular, round or oval cross section. The stator structures can serve as stator cores for stator coils. Depending on the design of the electric motor, stator coils can be arranged on all stator structures or at least one stator structure can be provided as a spacer between two adjacent stator coils.

According to a further embodiment, compensating structures spaced apart from one another on the circumferential side are formed on the compensating section, the compensating structures being shaped as axial end sections of the stator structures. By means of such compensating structures, a surface of the compensating section in the area of the rotor can be shaped similar to or identical to a surface of the coil section. The stator can thus have a uniform structure or shape over the entire circumference, by means of which the rotor is magnetically attracted uniformly along the entire circumference. This measure results, in particular, in a uniform rotation of the rotor and reduces unbalance of the rotor.

According to a further exemplary embodiment, the rotor is spaced apart from the stator structures in the axial direction. The rotor preferably covers at least some areas of the stator structures in the radial direction. As a result, the rotor is arranged along the axis of rotation vertically above the stator or the poles of the stator. The stator coils can thus interact axially with the permanent magnets of the rotor. As a result of this measure, the rotor can have a larger diameter, so that a higher torque can be generated on the shaft by the electric motor.

The rotor can have a diameter which corresponds to a diameter of the stator or which projects beyond the diameter of the stator. In this embodiment, the permanent magnets of the rotor can have magnetic field lines which pass through the rotor in the axial direction or emerge from the rotor. The permanent magnets can, for example, be glued to the rotor or inserted into corresponding recesses in the rotor with a force fit.

According to a further embodiment, the rotor is spaced apart from the stator structures in the radial direction and is arranged rotatably in the area of the axial end sections of the stator structures. The rotor can thus be arranged in the axial direction parallel to the stator structures. In particular, the permanent magnets of the rotor can be arranged on the rotor in such a way that the magnetic field lines emerge from the rotor in the radial direction. The stator coils can thus interact electromagnetically with the permanent magnets of the rotor laterally or radially in the direction of the axis of rotation.

The stator coils can be wound or aligned in such a way that the generated magnetic field lines emerge from the stator coils in the axial direction. The stator structures can be used to deflect the magnetic field lines and / or to guide them in the direction of the rotor. Alternatively, the stator coils can be oriented radially in the direction of the axis of rotation.

The rotor can have a diameter which is smaller than the diameter of the stator. In particular, the diameter of the rotor can be dimensioned such that the stator surrounds the rotor on the circumferential side. In this embodiment, the permanent magnets of the rotor can have magnetic fields which emerge from the rotor in the radial direction. An electric motor configured in this way can be manufactured with a particularly compact overall height.

According to a further exemplary embodiment, a free space or a second receiving space, in particular for receiving a gear, is formed below the compensating section in the axial direction. As a result of this measure, a partial volume of the electric motor can be used to accommodate a transmission, as a result of which an electromechanically driven transmission actuator can be implemented with a reduced installation space requirement.

According to a further embodiment, the coil section has at least two stator coils, the stator coils being attached to adjacent stator structures or being spaced apart from one another by at least one stator structure. Such an arrangement of stator coils in the coil section can create redundancy in the drive of the electric motor, so that there are always at least two coils with current pulses simultaneously or one after the other can be acted upon in order to allow a uniform rotation of the rotor. The electric motor can have an odd number of stator coils, such as three, five, seven, new ones, or an even number of stator coils, such as two, four, six, eight.

According to a further embodiment, the at least one stator coil is designed as an air-core coil or is wound around at least one stator structure. The stator coils can be wound directly onto the respective stator structures or pre-wound and plugged onto the stator structures. As a result, a flexibly designed arrangement and design of the stator coils can be selected depending on the field of application of the electric motor.

According to a further exemplary embodiment, the stator structures and / or the coil section and / or the compensation section are designed as solid material or as a laminated core. The stator can be formed in one piece or in several pieces. In particular, the stator can be produced by a casting process or consist of a sintered material. For example, the stator can consist of a hard magnetic or soft magnetic metallic material. Alternatively, the stator can be composed of one or more stamped and bent parts to reduce eddy current losses.

According to a further embodiment, the rotor has a plurality of permanent magnets arranged on the circumference or a multi-pole permanent magnet in the form of a circular ring. For example, the ring-shaped permanent magnet can consist of a sintered magnetized material. Alternatively, several permanent magnets distributed around the circumference can be arranged on the rotor. The permanent magnets can be oriented to act in the axial direction or in the radial direction.

According to a further aspect of the invention, an actuator, in particular an electromechanical transmission actuator, is provided. The actuator has an electric motor according to the invention, the electric motor being arranged in a housing. The housing can have a hexahedral shape or be adapted to a shape of the electric motor.

Due to the stepped stator, the electric motor is configured in such a way that a gearbox can be efficiently positioned together with the electric motor in a preferably hexahedral housing. The electric motor can be screwed, clipped, caulked or glued to the housing. In particular, bearings for receiving the shaft can be arranged on housing walls, a housing base and / or on a housing cover. As an alternative or in addition, the stator can have at least one bearing for receiving and for radially guiding the shaft.

In particular, such an electric motor can be integrated into a corner of a gear housing and thus create space for a gear.

An actuator configured in this way can have a particularly compact shape and thus require little installation space.

According to one embodiment, a gear is arranged in a free space in the housing formed by a compensating section. The compensating section, which is axially stepped by spacers, can thus create optimal access to the shaft of the rotor and enable an arrangement of the transmission which protrudes into the electric motor or into a volume of the electric motor.

According to a further exemplary embodiment, the transmission is designed as a gear transmission and / or a worm gear. As a result, the electric motor can transmit a rotational movement of the rotor via the shaft to the gearbox and provide a gear ratio for moving or deflecting components or parts.

• 1 eine perspektivische Darstellung eines Elektromotors mit einem Getriebe gemäß einer Ausführungsform,
• 2 eine Draufsicht auf den Elektromotor aus 1,
• 3 eine Draufsicht auf einen Aktuator mit einem Elektromotor aus 1,
• 4 eine schematische Schnittdarstellung eines Elektromotors gemäß der in 1 gezeigten Ausführungsform und
• 5 eine schematische Schnittdarstellung eines Elektromotors gemäß einer weiteren Ausführungsform.

In the following, preferred exemplary embodiments of the invention are explained in more detail with the aid of greatly simplified schematic representations. Show here

• 1 a perspective view of an electric motor with a transmission according to an embodiment,
• 2 a top view of the electric motor 1 ,
• 3 a plan view of an actuator with an electric motor 1 ,
• 4th a schematic sectional view of an electric motor according to the in 1 embodiment shown and
• 5 a schematic sectional view of an electric motor according to a further embodiment.

The 1 shows a perspective view of an electric motor 1 with a gear 2 according to one embodiment. The electric motor 1 has a stator 4th and a rotor 6th on.

The rotor 6th is disc-shaped and has a shaft 8th connected. The wave 8th runs congruently with an axis of rotation W of the rotor 6th . By the rotation of the rotor 6th becomes the wave 8th driven or rotated. Further points the rotor 6th Permanent magnets 7th on which in the 4th and 5 are illustrated.

The stator 4th is parallel to the rotor in an axial direction A. 6th arranged. The stator 4th has a coil section 10 or a yoke and a compensation section 12th . The coil section 10 and the compensation section 12th are shaped as circular ring segments. The coil section 10 is on two end-side sections by a spacer each 14th in axial direction A of the electric motor 1 from the compensation section 12th spaced. Together they form the coil section 10 with the compensation section 12th a stator 4th which is shaped as a stepped annulus.

The axial direction A is aligned parallel to the axis of rotation W or congruent with the axis of rotation W. A radial direction R extends transversely to the axial direction A. A circumferential direction U follows an outer edge 5 of the rotor 6th .

The coil section 10 has several stator structures 16 , 17th or so-called stator teeth in a first receiving space 25th on, which are designed as axially extended columns with a rectangular cross-section. The first recording room 25th is axially between the rotor 5 and the coil section 10 educated. The stator structures 16 , 17th extend in the axial direction A from the coil section 10 of the stator 4th .

The stator 4th has according to the embodiment three in the first receiving space 25th arranged stator coils 18th on. The stator coils 18th are on three stator structures 16 arranged and use these stator structures 16 as coil cores. The number of stator coils 18th can be any. The electric motor preferably has 1 at least two stator coils 18th on.

Between every two stator coils 18th is an optional stator structure 17th provided as a spacer. The spacers 14th have a shape that matches a shape of the stator structures 16 , 17th corresponds. The coil section 10 and the compensation section 12th are exemplary at right angles to the spacer 14th arranged. Alternatively, all stator structures 16 , 17th with stator coils 18th be wound or provided.

On the compensation section 12th are circumferentially spaced compensation structures 20th educated. The compensation structures 20th are as axial end sections of the stator structures 16 , 17th shaped, which in the axial direction A of the compensation section 12th towards the rotor 6th stick out. The compensation structures 20th and the stator structures 16 , 17th are evenly distributed in the circumferential direction U on the stator 4th arranged.

The wave 8th serves to drive the gearbox 2 . This is what the wave is for 8th with a first exemplary gear 22nd of the transmission 2 connected. By the rotation of the rotor 6th is about the wave 8th the first gear 22nd driven. The first gear 22nd can in turn other components of the transmission 2 such as a second gear 24 drive. The gear 2 protrudes into a free space 26th or a second receiving space into it, which through the axially spaced compensation section 12th is trained.

In the 2 FIG. 3 is a top plan view of the electric motor of FIG 1 shown. It is illustrated here that the coil section 10 and the compensation section 12th together a stator 4th form with a circular ring shape. The figure also shows that the transmission 2 due to the lateral or regional arrangement of the coils 18th in the free space 26th can protrude. This allows the transmission 2 with the electric motor 1 can be nested.

The 3 shows a plan view of an actuator 28 with an electric motor 1 out 1 . The actuator 28 has a hexahedral housing 30th on. The case 30th encloses an interior volume 32 . In the interior volume 32 of the housing 30th is the electric motor 1 with the gearbox 2 arranged.

The gear 2 protrudes in this way into the electric motor 1 into that a space-saving arrangement of the transmission 2 and the electric motor 1 in the case 30th is made possible.

The 4th illustrates the electric motor in a schematic sectional view 1 according to the in 1 embodiment shown. The rotor 6th has several permanent magnets 7th on. The permanent magnets 7th can also be designed as an annular permanent magnet with a large number of magnetic poles. Here is the permanent magnet 7th designed to act in axial direction A.

The stator coils 18th can be energized to generate magnetic fields, whereby the stator coils 18th with the permanent magnet 7th can interact. Because the rotor 6th in axial direction A from the stator structures 16 is spaced, the stator coils 18th via the stator structures designed as coil cores 16 on the permanent magnet 7th act. The arrows 36 illustrate a magnetic flux from the stator coils 18th about the stator structure 16 to the permanent magnet 7th .

It is also shown that the rotor 6th has an extension in the radial direction R, which is essentially an extension of the stator 4th in the radial direction R.

In the 5 is a schematic sectional view of an electric motor 1 shown according to a further embodiment. In contrast to the in 4th The embodiment shown is the rotor 6th in the radial direction R from the stator structures 16 spaced. In particular is the rotor 6th in the area of axial end sections 34 of the stator structures 16 rotatably arranged.

The rotor 6th In the exemplary embodiment shown, it has an expansion in the radial direction R which is less than an expansion of the stator 4th is. This allows the rotor 6th from the stator 4th and in particular the stator structures 16 , 17th be limited on the circumference.

The at least one permanent magnet 7th of the rotor 6th is here preferably designed to act radially, so that the stator 18th generated magnetic field lines with the permanent magnet 7th can interact optimally. The corresponding magnetic field lines are shown schematically by arrows 38 illustrated.

Claims (14)

Electric motor (1), in particular for an actuator (28), having a stator (4) with at least one stator coil (18) and having a rotor (6), the rotor (6) being rotationally symmetrical and having at least one permanent magnet (7) for interacting with the at least one stator coil (18), the rotor (6) being connected to a shaft (8) for driving a gear (2), characterized in that the stator (4) has a coil section (10) with the has at least one stator coil (18) and a compensating section (12), the coil section (10) and the compensating section (12) being designed as circular ring segments and being axially spaced from one another by spacers (14). Electric motor after Claim 1 wherein stator structures (16, 17) are arranged on the coil section (10) and extend axially from the coil section (10), at least one stator structure (16) being designed as a stator core for the at least one stator coil (18). Electric motor after Claim 1 or 2 , wherein circumferentially spaced compensation structures (20) are formed on the compensation section (12), the compensation structures (20) being shaped as axial end sections (34) of the stator structures (16, 17). Electric motor according to one of the Claims 1 to 3 , the rotor (6) being spaced apart from the stator structures (16, 17) in the axial direction (A), the rotor (6) concealing the stator structures (16, 17) at least in some areas in a radial direction (R). Electric motor according to one of the Claims 1 to 3 wherein the rotor (6) is spaced apart from the stator structures (16, 17) in the radial direction (R) and is rotatably arranged in the region of the axial end sections (34) of the stator structures (16, 17). Electric motor according to one of the Claims 1 to 5 wherein a free space (26), in particular for receiving a gear (2), is formed in the axial direction (A) below the compensating section (12). Electric motor according to one of the Claims 1 to 6th wherein the coil section (10) has at least two stator coils (18), the stator coils (18) being attached to adjacent stator structures (16) or being spaced from one another by at least one stator structure (17). Electric motor according to one of the Claims 1 to 7th , wherein the at least one stator coil (18) is designed as an air-core coil or is wound around at least one stator structure (16). Electric motor according to one of the Claims 1 to 8th , wherein the stator structures (16, 17) and / or the coil section (10) and / or the compensation section (12) are designed as solid material or as a laminated core. Electric motor according to one of the Claims 1 to 9 wherein the rotor (6) has a plurality of permanent magnets (7) arranged on the circumference or a multi-pole permanent magnet (7) in the form of a circular ring. Actuator (28), in particular an electromechanical actuator, having an electric motor (1) according to one of the preceding claims, wherein the electric motor (1) is arranged in a housing (30). Actuator after Claim 11 wherein a gear (2) is arranged in a free space (26) in the housing (30) formed by a compensating section (12). Actuator after Claim 11 or 12th , wherein the transmission (2) is designed as a gear transmission and / or as a worm gear. Expansion valve, which by an actuator (28) according to one of the Claims 11 to 13th can be actuated and / or regulated.

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