Geared motor having an electric motor and a transmission driven by the electric motor

Abstract

The invention relates to a geared motor having an electric motor and a transmission driven by the electric motor, the transmission having an eccentric gear stage driven by a rotor shaft of the electric motor, which eccentric gear stage drives a planetary gear stage of the transmission.

Description

[0001] Geared motor comprising an electric motor and a gearbox driven by the electric motor

[0002] Description:

[0003] The invention relates to a geared motor comprising an electric motor and a gear driven by the electric motor.

[0004] It is generally known that a gearbox has gear stages and can be driven by an electric motor.

[0005] From DE 102023 118 253 A1, a rotor arrangement for an electric motor is known as the closest prior art.

[0006] A positive-locking planetary roller gear is known from DE 102006 023 962 A1.

[0007] A controllable transmission is known from FR 548 909 A.

[0008] The invention is therefore based on the object of designing a gear motor that is as compact and powerful as possible.

[0009] According to the invention, the object is achieved in the geared motor according to the features specified in claim 1.

[0010] Important features of the invention in the geared motor are that the geared motor has an electric motor and a gear driven by the electric motor, wherein the gear has an eccentric gear stage driven by a rotor shaft of the electric motor, which drives a planetary gear stage of the gear.

[0011] The advantage here is that the geared motor is compact, as an eccentric gear stage is arranged upstream of a planetary gear stage. This allows for a high gear ratio. Since this requires extremely little space, the geared motor is efficient and powerful. A commercially available standard motor can be connected to the gearbox to form the geared motor. The eccentric disc is rotatably mounted via rolling bearings, which are supported and / or mounted radially outwards via rollers on the inside of the housing part. By connecting the rotor shaft of the electric motor to the eccentric disc, the rotor shaft is supported not only by the bearings of the electric motor but also by the rolling bearings and the rollers. However, the tolerances of the rollers can be selected accordingly, thus counteracting mechanical overdetermination.

[0012] Alternatively, one of the two bearings of the rotor shaft located in the electric motor is omitted or removed, so that the rotor shaft is supported by only a single bearing in the motor. In this way, the rotor shaft is rotatably supported via this bearing and the rotatably mounted eccentric disc of the gearbox. Mechanical overdetermination is thus strictly avoided.

[0013] In an advantageous embodiment, the rotor shaft is connected in a rotationally fixed manner, in particular by means of a keyway, to an eccentric disc of the eccentric gear stage. This is advantageous in that the rotor shaft can be precisely inserted into a bore in the eccentric disc and is thus not only rotationally fixed to the eccentric disc, but is also rotatably mounted by the eccentric disc.

[0014] In an advantageous embodiment, a first rolling bearing mounted on the eccentric disc is accommodated in a cage driven by first rollers, which roll on the radial outer circumference of the first rolling bearing and on the other hand on a shaft contour formed on the inside of a housing part, thus driving the cage. The advantage here is that, thanks to the eccentric arrangement of the rolling bearing, the rollers enable a rotational movement of the cage with a high gear ratio.

[0015] In an advantageous embodiment, the sun gear is mounted on the eccentric disc on one side and via the planetary gears on the other. This is advantageous because the sun gear requires no additional bearings and is accordingly aligned to the tolerances of the planetary gears and the gearbox housing.In an advantageous embodiment, a spline of the sun gear projects through the cage and / or is plug-connected to the cage, in particular to an internal toothing of the cage, wherein a running toothing of the sun gear, axially spaced from the spline, engages with planet gears which engage with a ring gear of the housing part or a ring gear received in the housing part, in particular wherein the planet gears are rotatably mounted on planet pins, in particular by means of respective bearings, and the planet pins are inserted into axial bores of a planet carrier, wherein the planet carrier is rotatably mounted at least by means of a bearing received in the housing part. It is advantageous in this case that the sun gear is connected to the cage in a rotationally fixed manner and thus the cage drives the sun gear.

[0016] In an advantageous embodiment, the rotor shaft is supported not only by a bearing in the electric motor, but also by the first rolling bearing and the first rollers. This is advantageous because the rotor shaft is stably supported and the eccentric disc can also be supported together with the rotor shaft.

[0017] In an advantageous embodiment, a second rolling bearing mounted on the eccentric disc is housed in a cage driven by second rollers, which roll on the radial outer circumference of the second rolling bearing and on a shaft contour formed on the inside of a housing part, driving the cage. Advantageously, the second rolling bearing is arranged eccentrically offset by 180° in the circumferential direction, thus reducing the imbalance.

[0018] In an advantageous embodiment, the shaft contour has a radial spacing that runs periodically in the circumferential direction. This is advantageous because it allows for simple manufacturing.

[0019] In an advantageous embodiment, the rotational axis of the second rolling bearing is aligned parallel to the rotational axis of the rotor shaft and spaced from the rotational axis of the rotor shaft, in particular wherein the rotational axis of the second rolling bearing is aligned parallel to the rotational axis of the rotor shaft during operation of the

[0020] The eccentric gear stage performs a circular motion around the rotational axis of the rotor shaft. The advantage here is that the second roller bearing is arranged eccentrically and thus rolls on the second rollers, which then drive the cage. The advantage here is that the rotational axis of the second roller bearing is spaced apart from the rotational axis of the first roller bearing and is preferably diametrically opposite.

[0021] In an advantageous embodiment, each of the second rollers extends radially through a respective recess in the cage. This advantageously allows the second rollers to drive the cage when the eccentric disc is set in rotation, causing the second rolling bearing to roll against the second rollers.

[0022] In an advantageous embodiment, either the rotor shaft is rotatably mounted by means of two bearings arranged in the motor housing and the rotor shaft is additionally rotatably mounted via the first rolling bearing and the first rollers, in particular wherein the stator winding of the electric motor is arranged in the axial direction between the two bearings, or the rotor shaft is rotatably mounted by means of a single bearing arranged in the motor housing and is additionally rotatably mounted via the first rolling bearing and the first rollers, in particular wherein the stator winding of the electric motor is arranged in the axial direction between the bearing and the eccentric disc.

[0023] The advantage here is that if there are two bearings in the motor, the rotor shaft is additionally supported via the rollers and is therefore over-supported if the tolerances of the diameters of the rollers are not adjusted accordingly.

[0024] In an advantageous embodiment, the housing part of the gear unit is centered on a flange part, in particular the bearing flange, of the motor housing and is fastened, in particular, with screws. This is advantageous because the gear unit is centered relative to the motor and the eccentric disc is aligned coaxially with the rotor shaft. This ensures sufficient concentricity in the eccentric gear unit.

[0025] In an advantageous embodiment, the eccentric disc is spaced axially from the motor housing. This advantageously allows the eccentric disc to be surrounded by the gear housing, yet the geared motor can still be designed very compactly. Further advantages are evident from the subclaims. The invention is not limited to the combination of features in the claims. Those skilled in the art will recognize further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures, particularly from the problem and / or the problem posed by comparison with the prior art.

[0026] The invention will now be explained in more detail using schematic illustrations:

[0027] Figure 1 shows a longitudinal section through a region of a gear motor according to the invention.

[0028] In Figure 2, the gear motor is partially transparent and shown in an oblique view.

[0029] As shown in the figures, the geared motor comprises a gearbox whose housing part 5 is connected to the motor housing 11 of the electric motor driving the gearbox. In particular, the housing part 5 is centered and secured to a flange part, in particular a bearing flange, of the motor housing 11. The flange part is connected, on its side facing away from the housing part 5, to a stator housing. On the side facing away from the flange part, a bearing flange is arranged for receiving a bearing of the rotor shaft of the electric motor.

[0030] The housing part 5 surrounds an eccentric gear stage of the transmission driven by the rotor shaft 14, wherein the eccentric gear stage drives a planetary gear stage of the transmission.

[0031] For this purpose, the eccentric gear stage has a hollow eccentric disc 13 which is placed on the rotor shaft 14 and is connected to the rotor shaft 14 in a rotationally fixed manner, in particular by means of a key connection.

[0032] A first bearing 8 is mounted on the eccentric disc 13, the axis of rotation of which is parallel to, but spaced from, the axis of rotation of the rotor shaft 14. Rollers 7 of a first row of rollers, spaced apart from one another in the circumferential direction, roll on the radial outer circumference of the first bearing 8. The rollers 7 are circumferentially and / or axially delimited by a recess in a cage 2, which is connected in a rotationally fixed manner to a sun gear 1. For this purpose, the sun gear 1 has a spline 16, spaced apart in the axial direction from a running gear 15 of the sun gear 1, onto which spline the cage 2 is mounted.

[0033] A bearing 12 housed in the eccentric disc 13 acts as an axial bearing for the sun gear 1. For this purpose, the outer ring of the bearing 12 is housed in the eccentric disc 13, and the end face of the sun gear 1 facing the bearing 12 rests against the inner ring of the bearing 12. The contact surface between this inner ring and the sun gear 1 thus has a single axial position and extends in the radial and circumferential directions.

[0034] The rotational axis of sun gear 1 is coaxial with the rotational axis of the rotor shaft. Due to the eccentric arrangement of the first bearing 8, the distance between the rollers 7 varies during the rotational movement of the cage 2.

[0035] Depending on the eccentric position, the rollers 7 roll radially outwards on the radial inside of the housing part 5, which has a wave contour, in particular a clear inner diameter and / or clear radial distance that is periodically dependent on the circumferential position.

[0036] Further rollers 10 of a second row are axially spaced from the rollers 7 of the first row and roll radially inward on the radial outer circumference of a bearing 9, which is also mounted on the eccentric disc 13, although the eccentric position is shifted by 180° in the circumferential direction. The further rollers 10 of the second row are also each limited by the cage 2 in the axial and circumferential directions. The further rollers 10 also roll radially outward on another shaft contour on the inside of the housing part 5.

[0037] When the rotor shaft 14 drives the eccentric disc 13, the cage is set in rotation and in this way the plug-connected sun gear 1 is driven, whereby a very high transmission ratio can be achieved with little space requirement.

[0038] The sun gear 1 driven in this way has a running toothing which is in engagement with planet gears 3 which roll radially outward on a ring gear toothing of the housing part.

[0039] Overall, a very high gear ratio can be achieved in a very small space.

[0040] Since the rotor shaft 14 is supported by two bearings accommodated in the motor housing 11 and, in addition, the rollers 7 and 10 are supported on the inside of the housing part 5 and also press onto the rotor shaft 14 via the bearings 8 and 9, the mechanical overdetermination is mitigated and / or tolerated by suitably designed tolerances. The housing part 5 has the special feature that, on the one hand, a ring gear toothing, in particular involute toothing, of the planetary gear stage and, on the other hand, the shaft contour of the eccentric gear stage are incorporated on its inside. The housing part 5 is formed in one piece. The two gear stages are thus centered relative to one another by means of the manufacture of the housing part. The shaft contour is preferably cycloidal in the circumferential direction and is therefore fundamentally different from the involute-toothed ring gear toothing.

[0041] Preferably, the rollers 7 are offset from the rollers 10 in the circumferential direction.

[0042] The axial bearing 12 is housed in an axially projecting annular collar area of ​​the eccentric disc 13. The collar area is axially spaced from the keyway connection area. In particular, the collar area protrudes in the axial direction of the eccentric disc 13 on the side facing the sun gear 1.

[0043] The planet carrier 4 is rotatably mounted via a bearing 6 accommodated in the housing part 5.

[0044] The planetary gears 3 are rotatably mounted on bolts, in particular by means of needle bearings, wherein the bolts are inserted into bores of a planetary carrier 4, which is rotatably mounted to the housing part 5 via the bearing 6.

[0045] In further embodiments according to the invention, the rotor shaft bearing accommodated in the flange part is omitted, thus constructing the electric motor with only a single bearing for the rotor shaft. When assembling the electric motor with the gearbox, the rotor shaft 14 is inserted into the eccentric disc 13, in particular connected in a rotationally fixed manner by means of a keyway, and is thus also supported within the gearbox via the eccentric disc 13. The tolerance of the rollers (7, 10) can then be selected such that the rotor shaft 13 is supported on the one hand by the rollers 7 and 10, and on the other hand by a bearing, in particular on the B-side of the electric motor, which acts as the sole bearing for the rotor shaft within the motor housing 11 of the electric motor. Therefore, any mechanical overdetermination is avoided. However, the electric motor cannot function without the gearbox.

[0046] In further embodiments according to the invention, the bearing 12 accommodated in the eccentric disc 13 functions as a bearing, in particular not only as an axial bearing, for the sun gear 1. For this purpose, the bearing 12 accommodated in the eccentric disc 13 is mounted on an axial end region of the sun gear 1. The outer ring of the bearing 12 is accommodated in the eccentric disc 13, and the inner ring of the bearing 12 is mounted on the stub-shaped, in particular cylindrical, axial end region of the sun gear 1. The bearing 12, together with the planetary gears 3, thus forms a bearing for the sun gear 1.

[0047] List of reference symbols

[0048] 1 sun gear

[0049] 2 cages

[0050] 3 planetary gear

[0051] 4 planet carriers

[0052] 5 Housing part

[0053] 6 warehouses

[0054] 7 front row roles

[0055] 8 first camp

[0056] 9 second camp

[0057] 10 second-row roles

[0058] 11 Engine housing

[0059] 12 thrust bearings

[0060] 13 Eccentric disc

[0061] 14 Rotor shaft

[0062] 15 Running gear

[0063] 16 spline

Claims

Patent claims:

1. Geared motor comprising an electric motor and a drive unit driven by the electric motor Gearbox, characterized in that the gearbox has an eccentric gear stage driven by a rotor shaft (14) of the electric motor, which drives a planetary gear stage of the gearbox.

2. Geared motor according to claim 1, characterized in that the rotor shaft (14) is rotationally connected, in particular by means of a key connection, to an eccentric disc (13) of the eccentric gear stage.

3. Geared motor according to one of the preceding claims, characterized in that a first rolling bearing placed on the eccentric disc (13) is accommodated in a cage (2) which can be driven by first rollers (7) which roll on the one hand on the radial outer circumference of the first rolling bearing and on the other hand on a shaft contour formed on the inside of a housing part (5) and drive the cage (2).

4. Geared motor according to one of the preceding claims, characterized in that the shaft contour has a radial distance which runs periodically in the circumferential direction.

5. Geared motor according to one of the preceding claims, characterized in that the axis of rotation of the first rolling bearing is aligned parallel to the axis of rotation of the rotor shaft (14) and is spaced from the axis of rotation of the rotor shaft (14), in particular wherein the axis of rotation of the first rolling bearing executes a circular movement around the axis of rotation of the rotor shaft (14) during operation of the eccentric gear stage.

6. Geared motor according to one of the preceding claims, characterized in that each of the first rollers (7) projects in the radial direction through a respective recess of the cage (2).

7. Geared motor according to one of the preceding claims, characterized in that a bearing (6) is accommodated in the eccentric disc (13) and acts as an axial bearing (12) for the sun gear (1), in particular wherein an end face of the sun gear (1) facing the bearing (6) bears against the inner ring of the bearing (6), in particular wherein the axis of rotation of the eccentric disc (13) is aligned coaxially to the axis of rotation of the sun gear (1), and / or that a bearing (6), in particular an outer ring of a bearing (6), is accommodated in the eccentric disc (13) and, in particular the inner ring of the bearing (6), is placed on a cylindrical region of the sun gear (1) of the planetary gear stage.

8. Geared motor according to one of the preceding claims, characterized in that a plug-in toothing (16) of the sun gear (1) projects through the cage (2) and / or is plug-connected to the cage (2), in particular with an internal toothing of the cage (2), wherein a running toothing (15) of the sun gear (1) axially spaced from the plug-in toothing (16) is in engagement with planetary gears, which are in engagement with a ring gear toothing of the housing part (5) or of a ring gear accommodated in the housing part (5), in particular wherein the planetary gears are rotatably mounted on planetary bolts, in particular by means of respective bearings (6), and the planetary bolts are in axial bores of a Planet carrier (4) are inserted, wherein the planet carrier (4) is rotatably mounted at least by means of a bearing (6) accommodated in the housing part (5).

9. Geared motor according to one of the preceding claims, characterized in that the rotor shaft (14) is mounted not only via a bearing (6) present in the electric motor, but also via the first rolling bearing and the first rollers (7).

10. Geared motor according to one of the preceding claims, characterized in that a second rolling bearing placed on the eccentric disc (13) is accommodated in a cage (2) which can be driven by second rollers (10) which roll on the one hand on the radial outer circumference of the second rolling bearing and on the other hand on a shaft contour formed on the inside of a housing part (5) and drive the cage (2).

11. Geared motor according to one of the preceding claims, characterized in that the shaft contour has a radial distance which runs periodically in the circumferential direction.

12. Geared motor according to one of the preceding claims, characterized in that the axis of rotation of the second rolling bearing is aligned parallel to the axis of rotation of the rotor shaft (14) and is spaced from the axis of rotation of the rotor shaft (14), in particular wherein the axis of rotation of the second rolling bearing executes a circular movement around the axis of rotation of the rotor shaft (14) during operation of the eccentric gear stage.

13. Geared motor according to one of the preceding claims, characterized in that each of the second rollers (10) projects in the radial direction through a respective recess of the cage (2).

14. Geared motor according to one of the preceding claims, characterized in that either the rotor shaft (14) is rotatably mounted by means of two bearings (6) arranged in the motor housing (11), and the rotor shaft (14) is additionally rotatably mounted via the first rolling bearing and the first rollers (7), in particular wherein the stator winding of the electric motor is arranged in the axial direction between the two bearings, or that the rotor shaft (14) is rotatably mounted by means of a single bearing (6) arranged in the motor housing (11) and is additionally rotatably mounted via the first rolling bearing and the first rollers (7), in particular wherein the stator winding of the electric motor is arranged in the axial direction between the bearing (6) and the eccentric disc (13).

15. Geared motor according to one of the preceding claims, characterized in that the housing part (5) of the gear is centered on a flange part, in particular bearing flange, of the motor housing (11) and is fastened in particular with screws, and / or that the eccentric disc (13) is spaced apart from the motor housing (11) in the axial direction.

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