Electric motor

Abstract

The present invention relates to an electric motor (1) having at least one housing (2), at least one rotor (3) and at least one stator (4), wherein the rotor (3) has at least one rotor shaft (5), and the rotor shaft (5) is supported by means of at least one first shaft bearing (8) and at least one second shaft bearing (9). An electric motor (1) in which an axial play of the rotor (3) can be easily determined after the assembly process is achieved by virtue of at least one bearing sleeve (10) being arranged between the first shaft bearing (8) and the rotor shaft (5), the bearing sleeve (10) having at least one flange (11), and the flange (11) of the bearing sleeve (10) being arranged between the rotor (3) and the first shaft bearing (8).

Description

[0001] Dr. Fritz Faulhaber GmbH & Co. KG, Faulhaberstraße 1, 71101 Schönaich

[0002] “Electric motor”

[0003] The invention relates to an electric motor comprising at least one housing, at least one rotor, and at least one stator. The rotor has a rotor shaft supported by at least one first shaft bearing and at least one second shaft bearing, in particular in the housing.

[0004] Electric motors are known in the prior art in a wide variety of designs. Some applications, such as aerospace engineering, require reliable and precise control using electric motors, which necessitates calibrating the operating axial play of an electric motor, particularly the rotor, within very narrow limits. This is the case, for example, when electric motors are used to control flaps, rudders, and other moving parts. With the motors known from the prior art, determining and, in particular, adjusting the axial play of the rotor is always associated with increased manufacturing and assembly effort.

[0005] The invention is therefore based on the object of providing an electric motor in which an axial play of the rotor can be determined in a simple manner after assembly.

[0006] The object is achieved in a generic electric motor with the features of the characterizing part of claim 1, namely in that at least one bearing sleeve is arranged, in particular radially, between the first shaft bearing and the rotor shaft, in that the bearing sleeve has at least one flange, and in that the flange of the bearing sleeve is arranged, in particular axially, between the rotor and the first shaft bearing.

[0007] The electric motor is also referred to simply as the motor below and has at least one housing. At least the rotor and the stator are arranged in the housing. The rotor has at least one rotor shaft, which is preferably fixedly connected to the rotor. The rotor preferably has at least one rotor magnet or a plurality of rotor magnets. The rotor magnet or magnets are advantageously embedded in a matrix, for example a matrix made of a plastic. The rotor, in particular with the matrix, is at least partially formed onto the rotor shaft, for example injection-molded, cast, or pressed onto it.

[0008] The rotor shaft is supported in the housing by at least one first shaft bearing and at least one second shaft bearing. The first shaft bearing and the second shaft bearing are spaced apart from each other along a longitudinal axis of the rotor shaft. The first shaft bearing and / or the second shaft bearing are designed, for example, as ball bearings or spherical roller bearings. The rotor shaft protrudes from the housing at at least one end of the housing.

[0009] The housing advantageously has a cylindrical outer shape. The housing is preferably made at least partially, in particular entirely, of a metal. Depending on the weight requirements of the electric motor, the housing is made in particular of aluminum or stainless steel.

[0010] In order to be able to determine the axial play of the rotor very precisely and, if necessary, calibrate it, the present invention advantageously provides for at least one bearing sleeve to be arranged, particularly in the radial direction, between the first shaft bearing and the rotor shaft. The bearing sleeve has at least one flange, which, in the assembled state, is arranged at least partially between the rotor and the first shaft bearing, particularly in the axial direction.

[0011] The bearing sleeve is preferably pushed directly onto the rotor shaft. In particular, the inner diameter of the bearing sleeve essentially corresponds to the outer diameter of the rotor shaft. In a first section, the bearing sleeve advantageously has an outer diameter that essentially corresponds to the inner diameter of the first shaft bearing, in particular the inner diameter of an inner ring of the first shaft bearing. The flange has a diameter that is larger than the first section. The flange is advantageously supported on its surface facing towards the first section against the first shaft bearing, in particular the inner ring of the first shaft bearing. The flange preferably extends at least over part of a height of the inner ring of the first shaft bearing. The first shaft bearing is preferably at least partially mounted in a housing flange formed integrally with the housing.The housing flange has at least one recess through which the bearing flange and the rotor shaft pass at least partially. The housing flange is preferably arranged at the end of the housing where the rotor shaft protrudes from the housing.

[0012] The use of the bearing sleeve offers the advantage over the prior art that the first shaft bearing can be removed after the rotor has been installed. This allows the rotor's axial play to be measured and, if necessary, calibrated or adjusted to a minimum. Minimal axial play of the rotor is particularly advantageous in applications where the motor is accelerated in directions parallel to the longitudinal axis of the rotor shaft or with portions parallel to the longitudinal axis of the rotor shaft, as minimal axial play reduces the impact forces between the rotor and other motor components, such as the ball bearing. This applies both to forward accelerations in the direction of the rotor's exit from the housing and to backward accelerations in the opposite direction. Furthermore, the bearing sleeve allows for the installation of a larger and / or more robust ball bearing, thereby increasing the permissible axial force.

[0013] According to a further embodiment, the adjustment or calibration of the axial play is advantageously carried out by arranging at least one calibration disk between the bearing sleeve, in particular the flange of the bearing sleeve, and the rotor. During assembly, a plurality of calibration disks of different thicknesses are advantageously kept on hand and the use of a calibration disk with a specific thickness is selected in order to set a desired axial play. For example, calibration disks with a thickness of 1 / 10 mm or 5 / 100 mm are available. A calibration disk, for example, has at least one recess and is pushed onto the rotor shaft with the recess and arranged between the rotor and the bearing sleeve. The bearing sleeve is then remounted on the housing, in particular the housing flange, together with the first shaft bearing.

[0014] It is particularly advantageous if the remaining axial play after adjustment or calibration is between 5 / 100 mm and 15 / 100 mm, preferably 5 / 100 mm.

[0015] In order to advantageously remove the bearing sleeve from the rotor shaft after assembly to determine the axial play, a further embodiment provides that the bearing sleeve has at least one extraction groove. The extraction groove is arranged, for example, on the end of the bearing sleeve opposite the flange and completely surrounds the bearing sleeve on its outer circumference. The extraction groove is arranged on the bearing sleeve in such a way that the bearing sleeve, together with the first shaft bearing, can be removed from the rotor shaft using the extraction groove.

[0016] In order to advantageously make the motor even more resistant to damage in the event of strong axial acceleration, it has proven advantageous according to a further embodiment if at least one first support disk is arranged on a first end side of the rotor and at least one second support disk is arranged on a second end side of the rotor. Axial acceleration is understood to be an acceleration in a direction parallel to the longitudinal axis of the rotor shaft or with components parallel to the longitudinal axis of the rotor shaft. The first support disk and the second support disk are, for example, glued to the rotor. In particular, the first and second support disks are glued to the matrix surrounding the rotor magnet or the rotor magnets, e.g. made of a plastic. The first support disk advantageously rests on the flange of the bearing sleeve or on a calibration disk arranged between the flange of the bearing sleeve and the rotor.

[0017] It has proven particularly advantageous if the first support disc and the second support disc are made of a metal, preferably bronze. The outer diameter of the first support disc and the second support disc preferably corresponds substantially to the outer diameter of the rotor.

[0018] The presence of the first support disc and the second support disc on the opposite ends of the rotor ensures an improved contact area between the first shaft bearing and the second shaft bearing and the rotor during axial acceleration. Furthermore, the presence of the support discs prevents direct contact or impact on the rotor.

[0019] According to a further embodiment of the electric motor, the first support disk has at least one section that tapers conically in the axial direction of the motor. This advantageously ensures that the first support disk can engage both the flange of the bearing sleeve and the rotor with an optimal contact surface.

[0020] It is further preferred if the second support disk at least partially overlaps the rotor. For example, the rotor magnet has a circumferential recess on its outer circumference at its second end, into which the second support disk at least partially extends. As a result, the second support disk not only rests against the axial end of the rotor, but also overlaps or encompasses the rotor at least partially.

[0021] In order to advantageously dissipate forces during axial acceleration and at the same time ensure the disassembly of the first shaft bearing after assembly of the rotor, a further embodiment provides for the first shaft bearing to bear against a housing flange formed integrally with the housing. The first shaft bearing is, for example, at least partially inserted into the housing flange, for example up to approximately half of its axial extent. The first shaft bearing advantageously bears against the housing flange on a side of the housing flange facing away from the rotor, i.e., is arranged on the housing flange from the outside.

[0022] The first shaft bearing is preferably oversized. The first shaft bearing is therefore larger than necessary to absorb the radial and axial forces that occur during operation. The oversizing is advantageous because it allows for the absorption of larger forces during axial acceleration of the motor, particularly when the motor is switched off and in reverse. The first shaft bearing is designed, for example, as an angular contact ball bearing, particularly as a shielded angular contact ball bearing.

[0023] In particular, to fix the first shaft bearing to the housing, it has proven advantageous according to a further embodiment if at least the first shaft bearing is arranged between the housing flange and a front flange detachably connected to the housing. The first shaft bearing is at least partially inserted into the front flange. The front flange is screwed to the housing flange, for example, with a plurality of screws. Due to the detachable fastening, the front flange can be removed even after the rotor has been installed in the housing of the electric motor, which also allows the first shaft bearing to be disassembled together with the bearing sleeve.

[0024] As an alternative to using a front flange, the first shaft bearing is arranged between the housing flange of the housing and a gear housing of a transmission connected to the electric motor. The first shaft bearing is, for example, at least partially inserted into the housing flange and partially into the transmission housing. This allows the transmission housing to be advantageously aligned using the first shaft bearing. Preferably, the transmission housing is also detachably connected to the housing flange. When a transmission housing is provided, the front flange is dispensable.

[0025] The resistance of the motor to damage during axial acceleration can be further increased by providing, according to a further embodiment of the electric motor, that the second shaft bearing rests against a support element connected to the housing, in particular a welded and / or screwed one. The support element is particularly advantageously screwed and welded in order to dissipate the greatest possible forces. The support element is also made of a metal, e.g., aluminum or stainless steel. The support element extends between the housing and the second shaft bearing and has at least one recess into which the second shaft bearing can be at least partially inserted.

[0026] Preferably, at least a portion of the motor electronics, e.g., Hall sensors, etc., is attached to the support element. For example, the support element has at least one feedthrough for electrical cables. Furthermore, it is particularly provided that the motor electronics are at least partially or completely encapsulated on the support element with a potting compound to advantageously increase resistance to impacts and vibrations.

[0027] To ensure advantageous power transmission, a further embodiment provides that an outer ring of the second shaft bearing has at least one shoulder, and that the shoulder rests in a corresponding groove on the support element. This secures the second shaft bearing against axial movement on the support element, allowing very large forces to be transmitted from the second shaft bearing to the support element.

[0028] According to a further embodiment, it has proven particularly advantageous if the rotor is preloaded in the direction of the flange of the bearing sleeve by at least one spring, in particular at least one spiral spring. The spiral spring is arranged, for example, such that the spring surrounds the rotor shaft. The spring preferably extends at least partially in a recess within the rotor, in particular within the rotor matrix. Furthermore, the spiral spring is supported on the second end side of the rotor against an inner ring of the second shaft bearing.

[0029] When the motor is accelerated in a forward direction, i.e., in the direction in which the rotor shaft exits the housing, the spring is fully compressed, so that the rotor bears against the support element and / or the second shaft bearing, in particular the outer ring of the second shaft bearing. Preferably, the rotor bears against the support element with its second support plate. The spring is preferably selected such that the rotor is preloaded with sufficient force toward the flange of the bearing sleeve to ensure that the rotor or the first support plate bears against the bearing sleeve during motor operation.

[0030] According to a further embodiment of the electric motor, the support element has at least one bearing ring, and the rotor, in particular with the second support disk, bears against the bearing ring upon axial acceleration in a forward direction under compression of the spring. Preferably, the rotor bears only against the support element, in particular against the bearing ring of the support element, during acceleration in the forward direction, and in particular not against the outer ring of the second shaft bearing.

[0031] In particular, to protect the motor electronics from damage during axial acceleration, a further embodiment of the electric motor provides for a potting compound to be arranged between the support element and a motor cover. Preferably, at least part of the motor electronics, in particular including sensors, preferably Hall sensors, and / or the electrical connections of the motor are arranged at least partially or completely in the potting compound. This makes them more robust and able to withstand shocks and vibrations. A motor having the features of one or more of the described exemplary embodiments is suitable for withstanding forward-directed axial accelerations, i.e. accelerations in the exit direction of the rotor shaft from the housing and essentially parallel to the longitudinal axis of the rotor shaft, of approximately 10,000 g to 20,000 g, in particular 14,000 g, without damage when switched off.In the opposite direction, i.e. in reverse, such a motor can withstand accelerations of between 5,000 g and 10,000 g, in particular 8,000 g, without damage when switched off.

[0032] Further advantageous embodiments of the invention emerge from the following description of the figures and the dependent subclaims.

[0033] They show:

[0034] Fig. 1 shows an embodiment of an electric motor in perspective view, and

[0035] Fig. 2 shows the embodiment according to Fig. 1 in a section along the longitudinal axis of the rotor shaft.

[0036] In the various figures of the drawing, identical parts are always provided with the same reference symbols.

[0037] With regard to the following description, it is claimed that the invention is not limited to the exemplary embodiments and thereby not to all or a plurality of features of the described combinations of features; rather, each individual partial feature of the / each exemplary embodiment is also important for the subject matter of the invention, independently of all other partial features described in connection therewith, and also in combination with any features of another exemplary embodiment. Fig. 1 and Fig. 2 show an exemplary embodiment of an electric motor 1. Fig. 1 shows the exemplary embodiment of the electric motor 1 in a perspective view, Fig. 2 shows the exemplary embodiment of the electric motor 1 in a section along the longitudinal axis L of a rotor shaft 5. The electric motor 1 has at least one housing 2 in which the components of the electric motor 1 are arranged. The electric motor 1 further has a rotor 3 and a stator 4.The rotor 3 has at least one rotor shaft 5, wherein the rotor shaft 5 is firmly connected to the rotor 3. The rotor 3 also has a plurality of rotor magnets 6 encapsulated in a plastic matrix 7. The rotor magnets 6 are preferably designed as permanent magnets. The rotor shaft 5 is mounted on the housing 2 by a first shaft bearing 8 and a second shaft bearing 9.

[0038] In order to be able to determine and, if necessary, adjust the axial play of the rotor 3 along the longitudinal axis L of the rotor shaft 5 after the rotor 3 has been mounted in the housing 2, the electric motor 1 has at least one bearing sleeve 10 in the radial direction between the first shaft bearing 8 and the rotor shaft 5. The bearing sleeve 10 also has at least one flange 11 which is arranged in the axial direction between an inner ring 8a of the first shaft bearing 8 and the rotor 3. The rotor 3 is supported in the axial direction via the bearing sleeve 10 and its flange 11 on the inner ring 8a of the first shaft bearing 8. At least one calibration disk 12 is arranged between the bearing sleeve 10 and the rotor 3 and has been introduced to reduce the axial play of the rotor 3.

[0039] So that the bearing sleeve 10 can be removed from the rotor shaft 5 after assembly, for example to determine the axial play of the rotor 3, the bearing sleeve 10 has a withdrawal groove 13 running around its outer circumference. A tool designed for this purpose - not shown - can engage in the withdrawal groove 13, for example, in order to remove the bearing sleeve 10 together with the first shaft bearing 8 from the rotor shaft 5. For power transmission in the housing 2, it has proven advantageous if the first shaft bearing 8 rests against a housing flange 14 formed integrally with the housing 2 on a side of the housing flange 14 facing away from the rotor 3. This allows the shaft bearing 8 to be advantageously removed from the outside during disassembly.

[0040] At least one first support disk 16 is arranged on a first end 15 of the rotor 3, and at least one second support disk 18 is arranged on a second end 17 of the rotor 3. The first support disk 16 and the second support disk 18 are made of bronze and glued to the rotor 3. The first support disk 16 bears against the flange 11 of the bearing sleeve 10. The first support disk 16 has a section that tapers conically in the axial direction of the motor 1 in order to advantageously bear against the flange 11 of the bearing sleeve 10 with a substantially matching diameter. The second support disk 18 is designed on the second end 17 such that it continuously engages at least partially over the rotor 3, here in particular in the area of ​​the matrix 7.

[0041] In the exemplary embodiment, the first shaft bearing 8, particularly as shown in Fig. 2, is arranged between the housing flange 14 and a front flange 19 detachably connected to the housing 2. The front flange 19 is screwed to the housing flange 14 with screws 20, so that it is detachable. After removing the front flange 19, the first shaft bearing 8 can be pulled off the rotor shaft 5 with the bearing sleeve 10.

[0042] For power transmission during acceleration of the motor 1 in the forward axial direction, a support element 21 is arranged in the housing 2 and is welded to the housing 2 and screwed to the housing 2. The support element 21 is advantageously made of a metal. The support element 21 is advantageously inserted at least partially into the cylindrical housing 2 in a form-fitting manner. The second shaft bearing 9 is at least partially arranged in a recess 22 in the support element 21. An outer ring 9b of the second shaft bearing 9 has a shoulder 23 which rests in a corresponding groove 24 in the support element 21 in order to be able to advantageously transmit forces during acceleration in the forward direction - i.e. in the direction in which the rotor shaft 5 exits the housing 2.

[0043] The rotor 3 is preloaded toward the flange 11 of the bearing sleeve 10 by a spring 25, which is designed here as a spiral spring. The spring 25 is supported on the second end 17 of the rotor 3 against an inner ring 9a of the second shaft bearing 9. Upon axial acceleration along the longitudinal axis L in a forward direction, the spring 25 is fully compressed, so that the rotor 3, with its second support disk 18, subsequently bears against the outer ring 9b of the second shaft bearing 9 and / or a bearing ring 26 of the support element 21 when the spring 25 is fully compressed.

[0044] At least a portion of the motor electronics 28, including Hall sensors, is arranged between the support element 21 and a motor cover 27 and is enclosed by a potting compound 29. The electrical connections 30 of the motor electronics 28 and the electrical connections 31 of the stator 4, here the phase connections, are led downwards out of the housing 2. The electrical connections 31 of the stator 4 are also at least partially enclosed by a further potting compound 32.

[0045] The invention is not limited to the illustrated and described embodiments, but also encompasses all equivalent embodiments within the meaning of the invention. It is expressly emphasized that the embodiments are not limited to all features in combination; rather, each individual partial feature can also have an inventive significance in itself, independently of all other partial features. Furthermore, the invention is not yet limited to the combination of features defined in claim 1, but can also be defined by any other combination of specific features of all the individual features disclosed as a whole. This means that, in principle, practically every individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application.

[0046] Reference symbol

[0047] 1 electric motor

[0048] 2 housings

[0049] 3 Rotor

[0050] 4 Stator

[0051] 5 Rotor shaft

[0052] 6 rotor magnet

[0053] 7 Matrix

[0054] 8 First shaft bearing

[0055] 8a inner ring

[0056] 8b Outer ring

[0057] 9 Second shaft bearing

[0058] 9a inner ring

[0059] 9b Outer ring

[0060] 10 bearing sleeve

[0061] 11 Flange

[0062] 12 Calibration disc

[0063] 13 Trigger groove

[0064] 14 Housing flange

[0065] 15 First end page

[0066] 16 First support disc

[0067] 17 Second end page

[0068] 18 Second support disc

[0069] 19 Front flange

[0070] 20 screw

[0071] 21 Supporting element

[0072] 22 Recess

[0073] 23 paragraph

[0074] 24 grooves

[0075] 25 spring

[0076] 26 Contact ring Motor cover Motor electronics Potting compound Motor electronics connections 28 Stator connections 4 Potting compound

Claims

Claims 1. Electric motor (1), comprising at least one housing (2), at least one rotor (3) and at least one stator (4), wherein the rotor (3) has at least one rotor shaft (5), wherein the rotor shaft (5) is mounted by at least one first shaft bearing (8) and at least one second shaft bearing (9), characterized in that at least one bearing sleeve (10) is arranged between the first shaft bearing (8) and the rotor shaft (5), that the bearing sleeve (10) has at least one flange (11), and that the flange (11) of the bearing sleeve (10) is arranged between the rotor (3) and the first shaft bearing (8).

2. Electric motor (1) according to claim 1, characterized in that at least one calibration disc (12) can be or is arranged between the bearing sleeve (10) and the rotor (3).

3. Electric motor (1) according to claim 1 or 2, characterized in that the bearing sleeve (10) has at least one removal groove (13) in order to remove the bearing sleeve (10) from the rotor shaft (5).

4. Electric motor (1) according to one of claims 1 to 3, characterized in that the first shaft bearing (8) bears against a housing flange (14) formed integrally with the housing (2), in particular that the first shaft bearing (8) bears against the housing flange (14) on a side of the housing flange (14) facing away from the rotor (3).

5. Electric motor (1) according to one of claims 1 to 4, characterized in that at least one first support disk (16) is arranged on a first end side (15) of the rotor (3) and at least one second support disk (18) is arranged on a second end side (18) of the rotor (3), advantageously that the first support disk (16) rests on the flange (11) of the bearing sleeve (10), in particular that the support disks (16, 18) are made of a metal, preferably bronze.

6. Electric motor according to one of claims 1 to 5, characterized in that the first support disc (16) has at least one section which tapers conically in the axial direction of the longitudinal axis (L) of the rotor shaft (5) and / or that the second support disc (18) at least partially overlaps the rotor (3) in a circumferential manner.

7. Electric motor (1) according to one of claims 1 to 6, characterized in that at least the first shaft bearing (8) is arranged between the housing flange (14) and a front flange (19) detachably connected to the housing (2), in particular that the front flange (19) is screwed to the housing (2).

8. Electric motor (1) according to one of claims 1 to 7, characterized in that the second shaft bearing (9) rests on a support element (21) connected to the housing (2), in particular welded and / or screwed, or is at least partially arranged in the support element (21).

9. Electric motor (1) according to one of claims 1 to 8, characterized in that an outer ring (9b) of the second shaft bearing (9) has at least one shoulder (23), and that the shoulder (23) rests in a corresponding groove (24) in the support element (21).

10. Electric motor (1) according to one of claims 1 to 9, characterized in that the rotor (3) is prestressed by at least one spring (25), in particular a spiral spring, in the direction of the flange (11) of the bearing sleeve (10), in particular that the spiral spring (25) is supported on the second end side (17) of the rotor (3) on an inner ring (9a) of the second shaft bearing (9).

11. Electric motor (1) according to one of claims 1 to 10, characterized in that the support element (21) has at least one bearing ring (26), in particular that the rotor (3), preferably with the second support disc (18), bears against the bearing ring (26) under compression of the spring (25) when the electric motor (1) is accelerated in the axial direction.

12. Electric motor (1) according to one of claims 1 to 11, characterized in that a potting compound (29) is arranged between a support element (21) and a motor cover (27), in particular that at least part of the motor electronics (28) and / or the electrical connections (30) of the motor (1) is arranged in the potting compound (29).

Images