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

Abstract

The invention relates to a system 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] System comprising an electric motor and a transmission driven by the electric motor

[0002] Description:

[0003] The invention relates to a system comprising an electric motor and a transmission 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 11 2009 001 968 T5, a variable valve control device is known as the closest prior art.

[0006] A shaft-hub connection is known from DE 102016209 819 B3.

[0007] A transmission is known from US 2009 / 0270215 A1.

[0008] A motor arrangement with a speed reducer is known from DE 11 2012 003 027 T5.

[0009] The invention is therefore based on the object of designing a gear motor that is as compact and powerful as possible.

[0010] According to the invention, the object is achieved in the geared motor according to the features specified in claim 1.

[0011] Important features of the system are that the system has a device drivable by a geared motor and a geared motor, comprising 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 eccentric gear stage has a rotatably mounted cage, characterized in that the cage has a continuous recess into which a shaft of a device to be driven can be inserted and connected in a rotationally fixed manner to the cage, wherein a sealing cover is inserted into the recess, in particular is received in the recess, in particular wherein the sealing cover is spaced apart from the shaft in the axial direction, wherein the axis of rotation of the shaft and the axis of rotation of the cage are aligned coaxially with one another.

[0012] The advantage here is that the interior of the eccentric gear is sealed from the output side of the eccentric gear. To this end, the sealing cover closes the continuous recess of the cage. It is spaced apart from the shaft, which is connected to the cage in a rotationally fixed manner. It is preferably positioned against a step, particularly the inner step, of the cage.

[0013] In an advantageous embodiment, the recess is designed as a stepped bore, with the sealing cover positioned against a step of the recess. This advantageously involves the sealing cover being positioned against the step, particularly the inner step, and thus being limited in the axial direction. The sealing cover is thus prevented from falling out of the recess by both the step and the shaft.

[0014] In an advantageous embodiment, the rotor shaft of the electric motor is connected in a rotationally fixed manner, particularly by means of a keyway, to an eccentric disc of the eccentric gear stage. This is advantageous because the drive of the eccentric disc is reliably guaranteed. This is because the keyway is a proven connection that is simple and cost-effective to manufacture.

[0015] In an advantageous embodiment, the cage has a plug-in internal toothing for connecting to the shaft of a driven device, and the shaft has a corresponding plug-in external toothing. This is advantageous in that a high torque can be transmitted. In an advantageous embodiment, a plug-in internal toothing is formed on the cage, into which the shaft is inserted and to which the shaft is positively connected. This is advantageous in that a high torque can be transmitted from the cage to the shaft.

[0016] In an advantageous embodiment, the recess has an area in the axial direction, particularly in the direction parallel to the rotational axis of the rotor shaft, between the sealing cover and the internal spline, whose largest clear inner diameter is larger than the largest clear inner diameter of the spline and also larger than the largest outer diameter of the sealing cover and / or the largest clear inner diameter of the cage receiving area that accommodates the sealing cover. This has the advantage that dangerously high air pressure cannot develop when inserting the shaft into the cage, thus preventing a defect.

[0017] In an advantageous embodiment, a bearing is accommodated in a housing part of the gearbox, which rotatably supports the cage, in particular, with an inner ring of the bearing being mounted on a cylindrical extension of the cage. Advantageously, the outer ring of the bearing is received and / or inserted into a receiving bore of the housing part, and the inner ring of the bearing is mounted on the cage, in particular on the cylindrical extension of the cage. The bearing can be designed as a ball bearing, cylindrical roller bearing, or other rolling bearing.

[0018] In an advantageous embodiment, the eccentric disc has, in particular on both sides, an axially directed recess which is interrupted in the circumferential direction by a respective thickened portion of the eccentric disc, in particular wherein the two thickened portions are arranged offset from one another by 180° in the circumferential direction. The advantage here is that this recess is formed on both axial end faces, whereby an offset of the two recesses from one another of 180° reduces or even prevents imbalance. By means of the recesses, not only can material be saved and the moment of inertia of the eccentric disc reduced, but more lubricant can also be absorbed in the interior of the eccentric gear, thus achieving improved lubrication. The thickened portion enables balancing of the eccentric construction. In addition, axial bores can also be introduced into the thickened portions in order to optimize mass distribution.In an advantageous embodiment, the area covered by the thickened portion in the axial direction encompasses the area covered by the recess in the axial direction. This is advantageous because the recess is completely interrupted. Furthermore, the imbalance of the eccentric design of the eccentric disc can be compensated for without requiring additional installation space in the axial direction.

[0019] In an advantageous embodiment, the respective recess is bounded radially inward by an inner collar projecting axially on the eccentric disc, in particular axially on both sides, and radially outward by an outer collar projecting axially on the eccentric disc, in particular axially on both sides. Advantageously, the two collar areas function as a contact surface for the respective components, in particular the rolling bearing or the rotor shaft with a keyway connection. This enables these components to engage over an extended axial area.

[0020] In an advantageous embodiment, axially directed bores are introduced into the thickened portion, in particular their bore axes are arranged on a mathematical cylinder surface. This is advantageous in that the axial bores serve as lubricant reservoirs, and during operation of the geared motor, lubricant can be pumped radially outward from the axial bores to the rolling bearings by centrifugal force.

[0021] Advantageously, the geared motor according to the invention has a gear stage integrated into the electric motor. This allows for a high gear ratio. Since this requires extremely little space, the motor is designed to be efficient and powerful.

[0022] A commercially available standard motor can be connected to the gearbox to form the geared motor. The eccentric disc is rotatably mounted via roller bearings, which are supported and / or mounted radially outwardly via rollers on the inside of the housing. By connecting the rotor shaft of the electric motor to the eccentric disc, the rotor shaft is supported not only by the electric motor bearings, but also by the roller bearings and the rollers. However, the tolerances of the rollers can be selected appropriately, thus counteracting mechanical overdetermination.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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 executes a circular movement around the rotational axis of the rotor shaft during operation of the eccentric gear stage. It is advantageous in this case that the second rolling bearing is arranged eccentrically and thus rolls on the second rollers, which then drive the cage. It is advantageous in this case that the rotational axis of the second rolling bearing is spaced from the rotational axis of the first rolling bearing and is preferably arranged diametrically opposite.

[0030] 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.

[0031] 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.

[0032] The advantage here is that if the motor has two bearings, the rotor shaft can be supported by these bearings. An overly precise additional support via the rollers can be avoided by adjusting the tolerances of the roller diameters.

[0033] 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. In an advantageous embodiment, the eccentric disc is spaced axially from the motor housing. This is advantageous because the eccentric disc is surrounded by the gear unit housing, yet the geared motor can still be designed very compactly.

[0034] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.

[0035] The invention will now be explained in more detail using schematic illustrations:

[0036] Figure 1 shows a gear motor according to the invention in a cut-away oblique view.

[0037] Figure 2 shows the gear motor in side view.

[0038] Figure 3 shows an eccentric disc of the gear motor in an oblique view from a first viewing direction.

[0039] Figure 4 shows the eccentric disc of the gear motor in an oblique view from a second viewing direction.

[0040] As shown in the figures, the geared motor comprises a gearbox whose housing part 5 is connected to the motor housing 1 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 1. 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.

[0041] The housing part 5 surrounds an eccentric gear stage of the transmission driven by the rotor shaft 4, wherein the eccentric gear stage drives a device not shown in the figures, such as another transmission.

[0042] For this purpose, a shaft of the device to be driven is connected in a rotationally fixed manner to a cage 2 of the eccentric gear stage. Either a keyed connection or a spline connection, as shown in Figure 2, can be used as the rotationally fixed connection. For this purpose, the cage 2 has a spline internal toothing into which the shaft of the device to be driven can be inserted with its corresponding spline external toothing.

[0043] The eccentric gear stage has the hollow eccentric disc 3, which is slipped onto the rotor shaft 4 and is connected to the rotor shaft 4 in a rotationally fixed manner, in particular by means of a keyway connection. A first bearing 8 is slipped onto the eccentric disc 3, the axis of rotation of which is aligned parallel to the axis of rotation of the rotor shaft 4 and whose axis of rotation is spaced from the axis of rotation of the rotor shaft 4. 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 delimited in the circumferential direction and / or in the axial direction by a recess in a cage 2, which can be connected to the shaft of the device to be driven in a rotationally fixed manner. For this purpose, the shaft of the device to be driven has a plug-in external toothing, which is inserted into the plug-in internal toothing 6 of the cage 2.

[0044] Due to the eccentric arrangement of the first bearing 8, the distance between the rollers 7 is variable during the rotational movement of the cage 2.

[0045] 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.

[0046] 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 3, although the eccentric position is shifted by 180° in the circumferential direction. The further rollers 10 of the second row are also each delimited 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.

[0047] If the rotor shaft 4 now drives the eccentric disc 3, the cage is set in rotation and in this way the shaft of the device to be driven, which is not shown in the figures and is connected to the cage 2, is driven, whereby a very high transmission ratio can be achieved with little space requirement.

[0048] Since the rotor shaft 4 is supported by two bearings housed in the motor housing 1, and the rollers 7 and 10 are supported on the inside of the housing part 5 and also press against the rotor shaft 4 via the bearings 8 and 9, the mechanical overdetermination is mitigated and / or tolerated by suitably designed tolerances. The housing part 5 has the shaft contour of the eccentric gear stage on its inside. The housing part 5 is formed in one piece. The shaft contour is preferably cycloidal in the circumferential direction and is thus fundamentally different from an involute-toothed ring gear.

[0049] Preferably, the rollers 7 are offset from the rollers 10 in the circumferential direction, in particular by 180° in the circumferential direction. This reduces imbalance.

[0050] The eccentric disc 3 has a recess extending axially, in particular a stepped bore with internal toothing, which encompasses the internal toothing 6. However, since the interior area of ​​the gear comprising the eccentric disc 3 is at least partially filled with lubricant, a sealing cover 11, in particular designed as a rubberized sheet metal part, is inserted into the continuous recess and positioned against a step of the continuous recess.

[0051] In the axial direction, i.e., in the direction parallel to the rotational axis of the rotor shaft 4, between the sealing cover 11 and the spline 6, the recess has a region whose largest clear inner diameter is larger than the largest clear inner diameter of the spline 6 and also than the largest outer diameter of the sealing cover 11 and / or than the largest clear inner diameter of the receiving area of ​​the recess that accommodates the sealing cover 11. This protects the sealing cover 11 from excess pressure that occurs or could occur when the shaft of the device to be driven is inserted into the spline 6.

[0052] The housing of the gearbox is formed by the housing part 5 and a funnel flange 13 connected to the housing part 5, the outer diameter of which increases monotonically, in particular strictly monotonically, with increasing axial distance from the housing part 5. Thus, a driven device that is larger than the gearbox can be connected.

[0053] The contact surface between the funnel flange 13 and the housing part 5 has a flat

[0054] Surface section contained in a mathematical plane that intersects the eccentric disc 3. The eccentric disc 3 is mounted on the rotor shaft 4 and is connected to the rotor shaft 4 in a rotationally fixed manner by means of a keyway.

[0055] As shown in Figures 3 and 4, the eccentric disc 3 has on its radial outer circumference an outer collar 30 projecting axially on both sides and uninterrupted in the circumferential direction and an inner collar 31 projecting axially on both sides and uninterrupted in the circumferential direction.

[0056] The inner collar 31 is arranged radially spaced from the outer collar 30 and / or radially within the outer collar 30. Radially between the inner collar 31 and the outer collar 30, a respective recess 32 is arranged on each side, axially formed in the eccentric disc, which is interrupted in the circumferential direction by a thickened portion 34 of the eccentric disc 3. The respective recess 34 preferably extends over more than 180°. Axial bores 33 are formed in the respective thickened portion 34.

[0057] The thickened portions 34 are diametrically opposed in the circumferential direction, making it easy to avoid imbalance. Alternatively, the thickened portions 34 can also be arranged in the same circumferential angle range, which requires precise balancing, especially for higher torques.

[0058] The recesses 34 are C-shaped.

[0059] Preferably, the axial bores 33 are all arranged at the same radial distance, i.e., at the same distance from the rotational axis of the rotor shaft 4. In particular, the axial bores 33 are evenly spaced from one another in the circumferential direction.

[0060] The respective rolling bearings 8 and 9 are mounted on the outer collar. The inner collar 31 enables an axially expanded connection area with the rotor shaft 4.

[0061] In further embodiments according to the invention, the bearing of the rotor shaft 4 accommodated in the flange part is omitted, and thus the electric motor is designed with only a single bearing for the rotor shaft 4. When assembling the electric motor with the gearbox, the rotor shaft 4 is inserted into the eccentric disc 3, in particular connected in a rotationally fixed manner by means of a keyway, and thus also mounted within the gearbox via the eccentric disc 3. The tolerance of the rollers (7, 10) can then be selected such that the rotor shaft 4 is mounted on the one hand via the rollers 7 and 10 and on the other hand via a bearing of the electric motor, in particular on the B-side, which acts as the only bearing for the rotor shaft within the motor housing 1 of the electric motor. This also avoids any mechanical overdetermination. However, the electric motor cannot function without the gearbox.

[0062] List of reference symbols

[0063] 1 engine housing

[0064] 2 cages

[0065] 3 eccentric disc

[0066] 4 Rotor shaft

[0067] 5 Housing part

[0068] 6 spline

[0069] 7 front row roles

[0070] 8 first camp

[0071] 9 second camp

[0072] 10 second-row roles

[0073] 11 Sealing cover, especially rubberized sheet metal part

[0074] 12 camps

[0075] 13 Funnel flange

[0076] 30 outer collar

[0077] 31 inner collar

[0078] 32 Deepening

[0079] 33 axial bore

[0080] 34 Thickening

Claims

Patent claims:

1. System, comprising a device drivable by a geared motor and a geared motor, comprising 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 eccentric gear stage has a rotatably mounted cage, characterized in that the cage has a continuous recess into which a shaft of a device to be driven can be inserted and connected in a rotationally fixed manner to the cage, wherein a sealing cover is inserted into the recess, in particular is received in the recess, in particular wherein the sealing cover is spaced apart from the shaft in the axial direction, wherein the axis of rotation of the shaft and the axis of rotation of the cage are aligned coaxially with one another.

2. System according to claim 1, characterized in that the recess is designed as a stepped bore, wherein the sealing cover is positioned against a step of the recess.

3. System according to one of the preceding claims, characterized in that the rotor shaft of the electric motor is connected in a rotationally fixed manner, in particular by means of a key connection, to an eccentric disc of the eccentric gear stage, and / or that the cage has a plug-in internal toothing for connection to the shaft of a device to be driven and the shaft has a corresponding plug-in external toothing.

4. System according to one of the preceding claims, characterized in that an internal plug-in toothing is formed on the cage, into which the shaft is inserted and with which the shaft is positively connected.

5. System according to one of the preceding claims, characterized in that in the axial direction, in particular in the direction parallel to the axis of rotation of the rotor shaft, between the sealing cover and the plug-in internal toothing, the recess has a region whose largest clear inner diameter is larger than the largest clear inner diameter of the plug-in toothing and is also larger than the largest outer diameter of the sealing cover and / or than the largest clear inner diameter of the receiving region of the cage receiving the sealing cover.

6. System according to one of the preceding claims, characterized in that a bearing is accommodated in a housing part of the gear, which bearing rotatably supports the cage, in particular wherein an inner ring of the bearing is placed on a cylindrical extension of the cage.

7. System according to one of the preceding claims, characterized in that the eccentric disc, in particular axially on both sides, each has an axially directed recess which is interrupted in the circumferential direction by a respective thickening of the eccentric disc, in particular wherein the two thickenings are arranged offset from one another by 180° in the circumferential direction, and / or that the area covered by the thickening in the axial direction comprises the area covered by the recess in the axial direction.

8. System according to one of the preceding claims, characterized in that the recess is delimited radially inwards by an inner collar projecting in the axial direction on the eccentric disc, in particular on both sides, and radially outwards by an outer collar of the eccentric disc projecting in the axial direction, in particular on both sides.

9. System according to one of the preceding claims, characterized in that axially directed bores are introduced into the thickening, in particular their bore axes are arranged on a mathematical cylinder jacket.

10. System according to one of the preceding claims, characterized in that a first rolling bearing placed on the outer collar and / or on the eccentric disc is accommodated in the cage which can be driven by first rollers 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 and drive the cage.

11. System according to one of the preceding claims, characterized in that the shaft contour has a radial distance that runs periodically in the circumferential direction, and / or that the axis of rotation of the first rolling bearing is aligned parallel to the axis of rotation of the rotor shaft and is spaced from the axis of rotation of the rotor shaft, 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 during operation of the eccentric gear stage, and / or that each of the first rollers projects in the radial direction through a respective recess of the cage.

12. System according to one of the preceding claims, characterized in that the rotor shaft is mounted not only via a bearing present in the electric motor but also via the first rolling bearing and the first rollers, and / or that a second rolling bearing placed on the outer collar of the eccentric disc and / or on the eccentric disc is accommodated in a cage that can be driven by second rollers, 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 and drive the cage.

13. System according to one of the preceding claims, characterized in that the shaft contour has a radial distance which runs periodically in the circumferential direction, and / or that the axis of rotation of the second rolling bearing is aligned parallel to the axis of rotation of the rotor shaft and is spaced from the axis of rotation of the rotor shaft, 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 during operation of the eccentric gear stage, and / or that each of the second rollers projects in the radial direction through a respective recess of the cage.

14. System according to one of the preceding claims, characterized in that 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 that 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.

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

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