Drive unit with a planetary gearbox

Abstract

Drive unit (10) with a planetary gear (1) comprising a sun gear (3) rotatable about a first axis (2) and a ring gear (5) rotatable about a second axis (4), and at least two planet gears (6) meshing with the sun gear (3) and the ring gear (5), wherein the two axes (2, 4) are arranged parallel and spaced apart from each other, wherein the planetary gear (1) comprises two planet gears (6), and wherein the planetary gear (1) comprises a first housing part and a second housing part, wherein the sun gear (3) and the planet gears (6) are mounted in the first housing part, wherein the sun gear (3) and the planet gears (6) are mounted in a common bearing part which is mounted in the first housing part, wherein the bearing part is designed as a bearing bracket (32) which has two receptacles (33) for bearing shafts (8) of the planet gears (6) and between the receptacles (33) a receptacle (34) for a shaft (9) of the sun gear (3),wherein the first housing part is designed as a cover (25) and the second housing part as a pot (26), wherein screws (35) serve to fasten the bearing bracket with bearing sections (36) of the cover (25), characterized in that the bearing sections (36) are axially projecting bearing sections (36), wherein the ring gear (5) is mounted in the second housing part, wherein the cover (25) is provided with three openings (37) for the passage of the bearing shafts (8) of planet gears (6) and the shaft (9) of sun gear (3).

Description

[0001] The invention relates to a drive unit with a planetary gear, wherein the planetary gear has a sun gear rotatable about a first axis and a ring gear rotatable about a second axis as well as at least two planet gears meshing with the sun gear and the ring gear.

[0002] Drive units require increasingly higher transmission forces when using transmissions. This is the case, for example, when the transmission interacts with an electrical machine, be it an electric motor or an electric generator.

[0003] The electric motor drives the transmission; the transmission drives the electric generator to generate electricity.

[0004] Given the relatively limited installation space available, the required transmission forces cannot be handled by gearboxes with spur gear stages or planetary gearboxes with a single ring gear stage. For example, a spur gear gearbox has an insufficient center distance for the required forces. A ring gear gearbox results in gear loads that are too high for the required forces.

[0005] A drive unit is known from DE 36 40 947 A1. The drive unit comprises a transmission for a steerable wheel of a motor vehicle. The transmission contains an input gear for reducing the speed, which, via two two-stage intermediate gears, rotates a ring gear connected to a wheel hub. In this way, only low torques can be transmitted to the wheel hub.

[0006] DE 10 2009 002 089 A1 describes a transmission unit for driving a vehicle wheel. A drive shaft and an output shaft of the transmission unit are transversely movable relative to each other. Specifically, a planetary transmission is provided in which both ends of the axis of a planetary gear are each held in their own planetary carrier. In this way, the planetary gear is constantly guided by the two planetary carriers, which are pivotally coupled by means of their common planetary axis, so that the planetary gear is in permanent use both with an input change and with an output ring gear.

[0007] DE-A 20 33 222 describes a gear transmission with power split for the final drive of heavy motor vehicles, particularly tracked vehicles. Intermediate gears are rotatably mounted on a carrier between a ring gear connected to the output shaft and a drive shaft, and a pinion connected to the drive shaft or the output shaft. The ring gear or pinion is unsupported to balance the load. It is arranged eccentrically to the ring gear, in which unequal-sized intermediate gears are provided. The intermediate gears are evenly distributed around the circumference of the unsupported gear and mesh with the relocated gear at the same pressure angle.

[0008] DE 23 63 106 C2 describes a load balancing device for a planetary gear final drive of a heavy motor vehicle. A wheel body, to which the rim is usually attached, is bolted to the ring gear of the planetary gear. DE 23 63 106 C2 discloses the features of the preamble of patent claim 1.

[0009] The object of the present invention is to design the planetary gear in a drive unit in such a way that it ensures acceptable gearing loads for high required transmission forces or torques with optimal use of installation space and structurally simple mounting of the sun gear and planet gears.

[0010] The invention proposes a drive unit having the features of patent claim 1.

[0011] The planetary gear set comprises two planetary gears. These, in particular, have the same diameter. The axes of the sun gear and ring gear are arranged parallel and spaced apart from each other.

[0012] The planetary gear is structurally particularly advantageous since it has a first housing part and a second housing part, wherein the sun gear and the planet gears are mounted in the first housing part and the ring gear is mounted in the second housing part.

[0013] The two housing parts are designed in particular as interacting components, for example in the form of a pot and a lid closing the pot.

[0014] In particular, the cover serves to hold the sun gear and planetary gears, while the pot serves to hold the ring gear.

[0015] According to the invention, a structurally simple mounting of the sun gear and planetary gears is achieved, as they are mounted in a common bearing component located in the first housing part. The sun gear and planetary gears are thus mounted indirectly in the first housing part or in the cover.

[0016] To ensure a secure connection between the two housing parts, they are screwed together.

[0017] Preferably, the planetary gear is designed as a single unitary cartridge connected to a bearing element that forms part of the drive unit. Accordingly, the planetary gear can be completely assembled from its individual parts, and it is then only necessary to connect the thus formed cartridge to the bearing element. This significantly reduces the manufacturing and assembly effort of the drive unit.

[0018] The planetary gear is connected, in particular, in a torque-transmitting manner to an electrical machine configured as an electric motor and / or a generator. Thus, an electric motor can drive the planetary gear directly or indirectly, and a component connected to an output of the planetary gear can be driven via the planetary gear. Alternatively, it is possible to drive the generator using the planetary gear. The component drives the planetary gear via the input of the planetary gear, and the planetary gear drives the generator. The planetary gear can interact with an electrical machine that combines the functions of both an electric motor and an electric generator.

[0019] In the context of the variants described above, for example, in the planetary gear system, the first axle is a drive axle and the second axle is an output axle. In this case, the sun gear is preferably driven by an electric motor. In particular, a wheel, preferably a wheel of a vehicle, can be driven by the ring gear.

[0020] Alternatively, the second axle can be a drive axle and the first axle an output axle. In this case, the ring gear can be driven by a wheel, preferably a vehicle wheel or a wind turbine. The electric generator can then preferably be driven by the sun gear.

[0021] Further features of the invention emerge from the subclaims, the attached drawing and the description of the preferred embodiment shown in the drawing, without being limited to this.

[0022] It shows: Fig. 1 a schematic diagram of a first embodiment of a planetary gear used in the drive unit, Fig. 2 a schematic diagram of a modified embodiment of a planetary gear used in the drive unit, Fig. 3 a spatial representation of the components of the planetary gear comprising the gear wheels according to the embodiment according to Fig. 1, Fig. 4 a spatial representation of the drive unit having the planetary gear, which is used in connection with a rear swing arm of a motorcycle, Fig. 5 a side view of the drive unit according to Fig. 4 planetary gear used, which is designed as a cartridge, with the drive gear assigned to the sun gear of the gear, Fig. 6 a sectional view through the arrangement according to Fig. 5, Fig. 7 a spatial view of a pot forming part of the gearbox housing, Fig. 8 a spatial view of the pot according to Fig. 7 and the ring gear of the planetary gear, illustrated in an exploded view, Fig. 9 a spatial view of a cover forming part of the gearbox housing, Fig. 10 a spatial view of the Fig. 9 shown cover with bearings for the two planetary gears and the sun gear and drive gear connected to the sun gear, Fig. 11 a spatial view of the meshing gears of the planetary gear including the drive gear connected to the sun gear and the output gear connected to the ring gear, Fig. 12 a spatial view of a bearing part forming part of the drive unit, which is designed as a rocker, Fig. 13 a view of the drive unit according to arrow A in Fig. 4.

[0023] In the drive unit described in more detail below, as is generally the case Fig. 1 illustrates the use of a planetary gear 1. This comprises a sun gear 3 rotatable about a first axis 2 and a ring gear 5 rotatable about a second axis 4. Furthermore, the planetary gear comprises two planet gears 6 meshing with the sun gear 3 and the ring gear 5. Perpendicular to the plane of the sheet according to Fig. 1 axes 2 and 4 of the planetary gear 1 are arranged parallel and spaced apart from each other. This center distance is in Fig. 1 is illustrated by the distance dimension B. This distance dimension B is a specified center distance. Within the framework of this specified center distance, the aim is to ensure acceptable gear loads in the planetary gear unit 1 for the high required forces in order to better utilize the installation space. It is assumed that in normal operation of the planetary gear unit 1, which is understood to mean motor operation, the first axis 2 is assigned to the drive and the second axis 4 is assigned to the output. The planetary gear unit 1 can certainly be operated in the opposite direction, in conjunction with a generator. In this case, forces are introduced via the second axis 4 and derived via the first axis 2. For the sake of simplified designation of the components of the planetary gear unit and the drive unit to be described in more detail below, the first axis 2 is assumed to be the drive axis and the second axis 4 is assumed to be the output axis.

[0024] In the planetary gear 1, the power is transmitted from an input shaft via the sun gear 3 to the two planetary gears 6, and from there to the ring gear 5 and its output. Because the output stage is a ring gear, only a small amount of space is required.

[0025] The axes of the planet gears 6 are designated by the reference number 7.

[0026] The embodiment of the planetary gear 1 according to the Fig. 2 differs from the embodiment according to Fig. 1 only in that a third planetary gear 6 is provided, which can rotate about an axis 7 and meshes with the sun gear 3 and the ring gear 5. This ring gear is arranged on the side of the ring gear 5 facing away from the two planetary gears 6 of equal diameter and has a significantly larger diameter than the sun gear 3 and the two equally sized planetary gears 6.

[0027] In this embodiment, the torque introduced into the planetary gear 1 is not introduced via two planetary gears 6, but via three planetary gears 6 from the sun gear 3 into the ring gear 5.

[0028] In this embodiment, the same predetermined center distance can be used as in the embodiment according to Fig. 1 realize.

[0029] Fig. 3 illustrates the elements of the embodiment according to Fig. 1 in constructive details; the reference numbers used here correspond to those according to Fig. 1.

[0030] Also shown are the bearing shafts 8 for the two planetary gears 6 and the shaft 9 which is non-rotatably connected to the sun gear 3.

[0031] Fig. Figure 4 illustrates the drive unit designated by reference number 10, which is used in conjunction with a rear axle of a motorcycle. The drive unit 10 has a bearing element designed as a swing arm 11. This is a cast part. The swing arm 11 has, in the region of one of its ends, a bearing receptacle 12 for the frame-side axle of the motorcycle, so that the swing arm 11 can swing about this axis. Spaced apart from the bearing receptacle 12, the swing arm 11 has, on its upper side, a further bearing receptacle 13. It serves to receive an axle, which is connected to a spring element, so that the swing arm 11, when moving about the bearing receptacle 12 in a counterclockwise direction, relative to the orientation according to Fig. 4, is moved against the force of the spring.

[0032] How complementary the Fig. 12, the rocker arm 11 is provided with a bearing receptacle 14 adjacent to the bearing receptacle 12 on one side of the rocker arm 11 and with a bearing receptacle 15 in the area of ​​the end facing away from the bearing receptacle 12 on the other side of the rocker arm 11. As can be seen from the illustration of the Fig. 4, the bearing support 14 serves to accommodate an electrical machine 16, which can be operated as an electric motor when power is supplied and as an electric generator when power is received.

[0033] The bearing mount 14 is provided with various bores 17 for receiving screws (not shown) that serve to connect the swing arm 11 and the electric motor 16. A pinion 19 is mounted in a rotationally fixed manner in an output shaft 18 of the electric motor 16. The pinion 19 is thus arranged on the side of the swing arm 11 facing away from the mounting side of the electric motor 16 in the swing arm 11.

[0034] The bearing mount 15 serves to accommodate the planetary gear 1. The planetary gear 1 is designed as a cartridge forming a unit, which is therefore also designated below with the reference number 1. The pre-assembled planetary gear or the pre-assembled cartridge is inserted into the bearing mount 15 and screwed to the rocker 11 in this area by means of screws 20. The shaft 9 of the sun gear 3 extends out of the housing 22 of the planetary gear 1 and there rotatably receives a drive gear 23. This and the pinion 19 are designed as gears around which a toothed belt 24 wraps. A toothed chain could easily be provided instead, which interacts with the pinion 19 and the drive gear 23.

[0035] The detailed structure of the planetary gear 1 or the cartridge as well as the components that interact directly with the planetary gear 1 is explained below using the illustration of the Fig. 5 to 11 described: The planetary gear or cartridge comprises a first housing part, designed as a cover 25, and a second housing part, designed as a cup 26. The sun gear 3 and the planetary gears 6 are mounted in the cover 25, and the ring gear 5 is mounted in the cup 26. The cover 25 and the cup 26 are screwed together. Threaded holes 27 in the cover 25 and corresponding bores 28 in the cup 26 are shown. The cover 25 and the cup 26 are connected by means of screws (not shown in detail) that pass through the bores 28 and are screwed into the threaded holes 27.

[0036] In particular, the representation of the Fig. 8 shows that the ring gear 5 and an output shaft 29 designed as a splined shaft form a single component. When the ring gear 5 is mounted relative to the cup 26, the output shaft 29 passes through an opening 30 in the cup 26. Fig. Figure 6 illustrates that an output flange 31 is mounted in the output shaft 29, outside the cartridge, in a rotationally fixed and axially fixed manner. The rear wheel of the motorcycle is attached to this output flange 31.

[0037] The Fig. 9 and Fig. 10 illustrate that the sun gear 3 and the two planet gears 6 are mounted in a common bearing part, which is designed as a bearing bracket 32. The bearing bracket 32 ​​has two receptacles 33 for the bearing shafts 8 of the planet gears 6. Between the receptacles 33, the bearing bracket 32 ​​also has a receptacle 34 for the shaft 9 of the sun gear 3. Screws 35 serve to fasten the bearing bracket 32 ​​to axially projecting bearing sections 36 of the cover 25. The cover 25 is provided with three openings 37 for the passage of the bearing shafts 8 of the planet gears 6 and the shaft 9 of the sun gear 3.

[0038] Again Fig. 12, the bearing receptacle 15 of the rocker arm 11 is provided with a circular opening 38 in the area of ​​the base of the bearing receptacle. This opening serves to accommodate the rotationally symmetrical projection 39 of the cup 26 with minimal radial play. Concentric to the opening 38, the bearing receptacle 15 is provided with inward-facing bearing surfaces 40, whereby the cup 26 is placed in the bearing receptacle 15 between the bearing surfaces 40 with minimal radial play. If the cartridge is inserted into the bearing receptacle 15 and not screwed to the rocker arm 11, the latter can thus pivot about the axis of the circular opening 38. Due to the offset of the axes 2 and 4 of the sun gear 3 and the ring gear 5, the first axis 2 of the sun gear 3 can be moved parallel to the rocker 11 when the cartridge rotates, as the second axis 4 of the ring gear 5 cannot be changed due to the geometric conditions.Rotating the cartridge in the bearing holder 15 by a certain, small pivoting angle results in the toothed belt 24, which wraps around the pinion 19 and the drive wheel 23, being tensioned or relaxed more strongly depending on the direction of rotation of the cartridge.

[0039] The Fig. 4, Fig. 10, Fig. 12 and Fig. 13 illustrate the means for securing the cartridge to the rocker 11 in different relative positions of the cartridge with respect to the rocker 11, as well as the means for pivoting and securing the cartridge with respect to the rocker 11: Fig.Figure 10 illustrates that the cover 25 and the cup 26 are provided with several, specifically four, elongated holes 41, which are arranged in the region of an outer flange section 42 of the cover 25 and the outer flange section 21 of the cup 26, respectively. Viewed along a circle, the elongated holes, which are curved in a circular arc, are evenly distributed. The circle on which the elongated holes 41 are arranged is concentric with a circle that passes through the bearing surfaces 40 of the bearing receptacle 15. The screws 20 pass through the elongated holes 41 and are screwed into threaded holes 43 in the rocker arm 11 in the region of the bearing receptacle 15. The screws 20 thus serve to fasten the cartridge to the rocker arm 11.

[0040] In the area of ​​a screw 20, specifically the one located between the upper and lower runs of the toothed belt 24, an angled bridge element 44 is connected to the cover 25 of the cartridge. This bridge element 44 is fastened by means of two screws 45 that pass through holes in a leg section of the bridge element 44 and are screwed into threaded holes in the flange section 21 of the cover 25. In the area of ​​a leg of the bridge element 44 facing away from this leg, the bridge element 44 is arranged parallel to the end face of the drive wheel 23 and, in the area of ​​its end associated with the shaft 9, accommodates a roller bearing 46 for supporting the outer free end of the shaft 9. At a distance from the shaft 9, this section of the bridge element 44 has a square opening 47 for inserting a square attachment of a tool.

[0041] The toothed belt 24 can be tensioned by inserting the tool with its square end into the square opening 47 of the bridge element 44, with the cartridge loosely screwed to the rocker arm 11 using the screws 20, and rotating the cartridge, which is mounted in the bearing surfaces 40 of the rocker arm 11, relative to the bearing receptacle 15 of the rocker arm 11 by slightly pivoting the tool and thus pivoting the bridge element 44. Due to the axial offset of axes 2 and 4 of the planetary gear 1, the toothed belt 24 is more strongly tensioned when the cartridge is pivoted in the corresponding direction. Relative rotation of the cartridge with respect to the rocker arm 11 is possible because the screws 20 penetrate the elongated holes 41 in the cover 25 and cup 26. The bridge element 44 is held in the desired clamping position of the cartridge by means of the tool, and the screws 20 are then firmly tightened.

[0042] Alternatively, the tool can be used, with the screws 20 relatively loose, to preset the rotational position of the cartridge relative to the rocker arm 11 via a coarse adjustment, and a fine adjustment can be made using a clamping screw 48 that is rotatably mounted in a correspondingly threaded receptacle 49 that is connected to the rocker arm 11. This clamping screw 48 can be unscrewed far enough that it rests against a stop 42 of the bridge element 44 and positions the bridge element 44 and consequently the cartridge in the desired pivot position relative to the rocker arm 11, thereby setting the desired pretension in the toothed belt 24. Only then are the screws 20 fully tightened.

[0043] If the electric machine 16 is used to drive the motorcycle, and thus functions as an electric motor, the drive force is transmitted via the electric motor and the pinion 19 interacting with it to the toothed belt 24, which interacts with the drive wheel 23. This drive wheel 23 drives the sun gear 3, which drives the ring gear 5 via the two planetary gears 6. The rear wheel of the motorcycle, which is connected to the output flange 31, is driven via the output shaft 29 assigned to the ring gear 5 and the output flange 31 interacting with it. When the power is reversed, for example when the motorcycle is braking, a torque is introduced in the opposite direction and thus introduced via the rear wheel of the motorcycle. In this case, the electric machine 16 acts as an electrical generator, which can be used to charge the motorcycle's battery.

[0044] The drive unit allows for a large reduction of the high maximum speed of the electric motor relative to the speed of the motorcycle's rear wheel. For example, the reduction ratio of the belt drive is 1:2, and that of the planetary gear is 1:4, resulting in a total ratio of 1:8. With an electric motor speed of 10,000 rpm, this results in a rear wheel speed of 1,250 rpm.

[0045] The described invention is by no means limited to the application of a motorcycle. For example, it is also possible to use the drive unit 10 in connection with power generation using a wind turbine. In this case, the bearing element is not a swing arm, but a stationary component, and a wind turbine interacts with the output shaft 29 of the planetary gear 1, which drives the electric machine designed as an electric generator via the planetary gear. List of reference symbols 1 planetary gear 2 First axis 3 sun gear 4 Second axis 5 ring gear 6 planetary gear 7 Axis 8 bearing shaft 9 Wave 10 Drive unit 11 Swingarm 12 Bearing recording 13 Stock recording 14 Bearing recording 15 Bearing recording 16 Electric machine 17 Hole 18 Output shaft 19 pinions 20 screw 21 Flange section 22 housings 23 Drive wheel 24 timing belts 25 lids 26 pot 27 threaded hole 28 Hole 29 Output shaft 30 Opening 31 Output flange 32 storage glasses 33 recording 34 recording 35 screw 36 storage section 37 Opening 38 Opening 39 Approach 40 storage space 41 slot 42 stop 43 threaded hole 44 bridge element 45 screw 46 rolling bearings 47 square opening 48 clamping screw 49 recording A Arrow B Distance measurement

Claims

[1] Drive unit (10) with a planetary gear (1) comprising a sun gear (3) rotatable about a first axis (2) and a ring gear (5) rotatable about a second axis (4), as well as at least two planet gears (6) meshing with the sun gear (3) and the ring gear (5), wherein the two axes (2, 4) are arranged parallel and spaced apart from one another, wherein the planetary gear (1) comprises two planet gears (6), and the planetary gear (1) comprises a first housing part and a second housing part, wherein the sun gear (3) and the planet gears (6) are mounted in the first housing part, wherein the sun gear (3) and the planet gears (6) are mounted in a common bearing part which is mounted in the first housing part, wherein the bearing part is designed as a bearing bracket (32) having two receptacles (33) for bearing shafts (8) of the planet gears (6) and, between the receptacles (33), a receptacle (34) for a shaft (9) of the sun gear (3) has,wherein the first housing part is designed as a cover (25) and the second housing part as a pot (26), wherein screws (35) serve to fasten the bearing bracket to bearing sections (36) of the cover (25), , characterized by that the bearing sections (36) are axially projecting bearing sections (36), wherein the ring gear (5) is mounted in the second housing part, wherein the cover (25) is provided with three openings (37) for the passage of the bearing shafts (8) of planet gears (6) and the shaft (9) of the sun gear (3). [2] Drive unit (10) according to claim 1, characterized by that the two housing parts are connected to each other, in particular screwed. [3] Drive unit (10) according to claim 1 or 2, characterized by that the planetary gear (1) is designed as a cartridge forming a unit which is connected to a bearing element forming a component of the drive unit (10). [4] Drive unit (10) according to one of claims 1 to 3, characterized by that the planetary gear (1) is connected in a torque-transmitting manner to an electrical machine (16) which is designed as an electric motor and / or as a generator. [5] Drive unit (10) according to one of claims 1 to 4, characterized by that the first axle (2) is a drive axle and the second axle (4) is an output axle. [6] Drive unit (10) according to claim 4 or 5, characterized by that the sun gear (3) can be driven by means of the electric motor. [7] Drive unit (10) according to one of claims 1 to 4, characterized by that the second axle (4) is a drive axle and the first axle (2) is an output axle. [8] Drive unit (10) according to claim 7, characterized by that the ring gear (5) can be driven by means of a wheel of a vehicle or by means of a wind turbine. [9] Drive unit (10) according to claim 7 or 8, characterized bythat the electric generator can be driven by means of the sun gear (3).

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