CN110925320A

CN110925320A - System comprising a rotor shaft and an output shaft, output shaft and method of manufacturing a system comprising a rotor shaft and an output shaft

Info

Publication number: CN110925320A
Application number: CN201910862758.9A
Authority: CN
Inventors: 汉斯-威利·雷德特
Original assignee: Hirschvogel Umformtechnik GmbH
Current assignee: Hirschvogel Umformtechnik GmbH
Priority date: 2018-09-20
Filing date: 2019-09-12
Publication date: 2020-03-27
Also published as: DE102018123116A1

Abstract

The invention relates to a system (1) comprising an output shaft (10) and a rotor shaft (20), the output shaft being connectable to the rotor shaft (20), in particular of an electric machine, for transmitting torque, the output shaft comprising: a base body (11) extending along a longitudinal direction and having: a first end face (S1) and a second end face (S2); and a flank (M) which, when viewed in the longitudinal direction, extends between the first end face (S1) and the second end face (S2), characterized in that a first toothing (31) for connection to the rotor shaft (20) is formed on the first end face (S1) and a second toothing (32) for transmitting the torque is formed on the flank (M).

Description

System comprising a rotor shaft and an output shaft, output shaft and method of manufacturing a system comprising a rotor shaft and an output shaft

Technical Field

The invention relates to a system comprising a rotor shaft and an output shaft, an output shaft and a method of manufacturing a system comprising a rotor shaft and an output shaft.

Background

Rotor shafts are well known in the art and are, for example, a basic component of an electric machine used in a hybrid vehicle. Such rotor shafts are described, for example, in DE 102014223390 a1 and DE 10016639C 1. In order to transmit the torque of the rotor shaft, which rotates during operation about the axis of rotation, during operation, an output shaft is provided, which is connected to the rotor shaft in the direction of the axis of rotation and which serves as a drive shaft for driving the other shafts.

Disclosure of Invention

In view of the prior art, it is an object of the present invention to provide a system comprising an output shaft (i.e. a drive shaft) and a rotor shaft, which system is improved compared to output shafts for rotor shafts of electric machines known in the prior art, in particular in terms of manufacturing and/or installation costs or in terms of weight.

According to the present invention, there is provided a system comprising an output shaft and a rotor shaft, the output shaft being connectable to the rotor shaft for transmitting or transferring torque, the output shaft comprising a base body extending in a longitudinal direction, the base body comprising:

a first end face and a second end face; and

a flank, which extends between a first end face and a second end face when viewed in the longitudinal direction, wherein a first toothing for connection to the rotor shaft is formed on the first end face and a second toothing for torque transmission is formed on the flank.

In contrast to the systems known from the prior art, in the present invention the first and second teeth are an integrated component of the output shaft. Thus, a plurality of functions, preferably the connection to the rotor shaft and the transmission to a further element that can be coupled to the output shaft (in particular the second toothing), are integrated in an easy-to-use assembly. In particular, the output shaft is simpler and smaller in size than systems known from the prior art and requiring complex plugging systems or the like. Here, smaller dimensions prove beneficial because the output shaft can be surface hardened with less delay. Preferably, the first and second teeth may be case hardened in a common processing step.

Preferably, the rotor shaft is an electric machine integrated in a vehicle, in particular a hybrid vehicle. During operation, the rotor shaft now rotates about the axis of rotation. The output shaft is directly connected to the rotor shaft in a longitudinal direction extending in parallel with the rotation axis. That is, the output shaft is directly connected to the rotor shaft through the first tooth portion. Here, it is to be understood that the first toothing of the interface between the rotor shaft and the output shaft serves in particular as a shift lever for rotating the output shaft together with the rotor shaft. The second tooth then transmits this rotation to another consumer component. Furthermore, the total length of the output shaft measured in the longitudinal direction is less than 0.3 times, preferably less than 0.2 times, particularly preferably less than 0.15 times the total length of the rotor shaft. For weight reduction, the rotor shaft is formed at least partially as a hollow body. In particular, the rotor shaft has an annular end face facing the output shaft in the mounted state, which end face is provided with a rotor shaft-side toothing. The first toothing is preferably designed to be compatible with the rotor shaft-side toothing. The first toothing can also be formed in a ring shape on the first end face or extend over the entire area on the first end face. In this case, in particular, the person skilled in the art understands the area of the first end face other than the hole (aussaprun) or opening for the passage of the fastener on the first end face as the entire area.

According to a first preferred embodiment of the invention, the first toothing is a face toothing (Hirth-Verzahnung) and/or the second toothing is a helical toothing. By means of the face toothing, a simple connection between the rotor shaft and the output shaft can advantageously be achieved, in particular without the use of a plug-in system which would otherwise be required. Furthermore, the rotor shaft may be conventionally manufactured without the need for a hardening process. In particular, the use of helical gearing has proven to be advantageous in terms of smoothness and relatively low noise. In particular, a helical toothing is to be understood as: in the helical toothing, the tooth tips of the individual teeth of the toothing, which extend in the longitudinal direction, are inclined relative to the rotor shaft, preferably by an angle of between 45 ° and 90 °. In addition, a face tooth is understood to mean an axially effective flat-sided or face tooth. Another advantage of using face teeth is that, without further encircling assemblies, self-centering and a relatively space-saving interface between the rotor shaft and the output shaft is possible.

In another embodiment, the output shaft is integrally formed. By the integral design, an output shaft can advantageously be provided which is compact and can be manufactured in one manufacturing step. In particular, integral is to be understood as meaning material-identical or as meaning integral components which are not composed or formed from several components by a positive-fit connection, a force-fit connection or a material-bonded connection. Advantageously, the output shaft is made of metal, and in particular by molding. Particularly preferably, the output shaft and its first and second toothing are forged in one piece in unison. For example, the output shaft is manufactured by hot forming, semi-hot forming and/or thixoforging (Thixoschmieden). Here, the deformation of the forged form is reflected in the altered crystal structure of the forged component. Therefore, the structure and mechanical characteristics of the output shaft are significantly changed.

Preferably, the output shaft has a hole formed between the first end face and the second end face and preferably concentric with the side face, through which the fastener passes in the mounted state of the output shaft. With the fastener passing through the aperture, stress may advantageously be provided on the face teeth of the first end face. That is to say, the output shaft is clamped in the mounted state between the head element of the fastening element and the rotor shaft. For example, the fastener is a bolt, in particular a hexagon head bolt or a socket head bolt. Preferably, the fasteners passing through the apertures engage in corresponding threads in the rotor shaft. Furthermore, it is conceivable for the second end face for forming the contact surface to be stepped, as a result of which the fastener, in particular the head element of the fastener, can be at least partially recessed into the second end face.

In particular, the second tooth section extends over a first length when viewed in the longitudinal direction, wherein the ratio of the first length to the total length of the output shaft measured in the longitudinal direction has a value between 0.3 and 0.8, preferably between 0.4 and 0.75, and particularly preferably between 0.4 and 0.55. It has proven to be advantageous if the second toothing does not extend over the entire length or the entire length of the output shaft, since the material and the corresponding weight of the output shaft can thereby be reduced. At the same time, such a second toothing with a first length can be formed in the above-mentioned dimensions, which second toothing is particularly suitable as a bevelled toothing in order to achieve an optimum smoothness and a minimum of noise.

Preferably, the second tooth is spaced apart from the first end face by a first spacing when viewed in the longitudinal direction, wherein the ratio of the first spacing to the total length of the output shaft measured in the longitudinal direction has a value of between 0.2 and 0.5, preferably between 0.3 and 0.45, and particularly preferably between 0.3 and 0.4. That is, the second tooth portion does not directly abut the first end face, but is sufficiently spaced from the first end face. This proves to be advantageous because space is thereby provided for the elements for receiving the torque from the output shaft. Furthermore, due to the given relatively small size of the first distance, the torsional effect does not significantly affect the output shaft, since the distance to the first toothing (i.e. the distance to the first end face) is relatively small.

In particular, a contact surface for a head element of the fastener is formed in the base body, wherein preferably a ratio of a second distance measured in the longitudinal direction between the contact surface and the end face to the first distance is between 0.7 and 1.3, preferably between 0.8 and 1.2, and particularly preferably between 0.9 and 1.1. By forming the contact surface in the basic body, in particular in the half area of the output shaft facing the first end face, a relatively short fastening element can advantageously be used. This contributes positively to the total weight of the system comprising the output shaft, the fasteners and the rotor shaft. In particular, the bore is dimensioned such that a cross-sectional dimension of the bore, measured perpendicularly with respect to the longitudinal extension, can cause the head element of the fastener to be pushed all the way to the contact face in the basic body. Preferably, the ratio of the bore cross section to the cross section of the output shaft measured in the same plane, in particular in the region outside the second toothing, has a value of between 0.3 and 0.8, preferably between 0.4 and 0.7, and particularly preferably between 0.5 and 0.65. By means of the relatively large bore cross section, as much material and weight as possible can be saved for the output shaft. At the same time, the wall of the output shaft formed by the through-hole is dimensioned such that no shear forces lead to a rotation of the output shaft when a torque occurs. Furthermore, the head element of the fastening element preferably has a recess, wherein the recess is preferably formed on the end face, so that a tool can be engaged through the hole in the output shaft until it engages in the recess of the fastening element in order to fix the fastening element on the rotor shaft.

In particular, the rotor shaft and the output shaft are designed such that they form an interface in the region of the first end face of the output shaft and the rotor shaft-side toothing, by means of which the connection of the rotor shaft and the output shaft can be achieved. In particular, in the interface region formed here, the outer side of the rotor shaft is dimensioned such that, when viewed in the longitudinal direction, the outer side of the rotor shaft and the side surface of the output shaft merge flush with one another. That is, the rotor shaft and the output shaft form a common outer surface without steps. Thus, for example, the co-formed outer surfaces may form bearings or the like. Alternatively, it is conceivable that the bearing region is formed only in the connection region of the rotor shaft. In particular, the flush transition between the rotor shaft and the output shaft has the advantage that a sealing ring, which would otherwise surround the rotor shaft and the drive shaft (i.e. the output shaft), for example in this region, can be dispensed with. This has a positive effect on the space economy and weight of the system.

According to a further embodiment of the invention, the side faces are, in the mounted state, connected flush to the outside of the rotor shaft, as seen in the longitudinal direction.

Another aspect of the invention is an output shaft for a system according to the invention. All features described for the system may be applied to the output shaft and vice versa.

Another aspect of the invention is a method for producing an output shaft, in particular an output shaft according to the invention, wherein the output shaft, in particular the first and second toothing, is produced by a forming process, in particular forging. All features and advantages described for the output shaft and the system may similarly be applied to the method of manufacturing the output shaft and vice versa. In particular, the forging process makes it possible to produce a compact and load-bearing output shaft, by means of which torque can be transmitted from the rotor shaft to the other element via the output shaft. Furthermore, it is also conceivable that only the first tooth or only the second tooth is hardened in the hardening step. Preferably, the first and/or second toothing are hardened in a common machining step.

Further advantages and features are given in the following description of preferred embodiments of the invention with reference to the drawings. The individual features of each embodiment can be combined with one another within the scope of the invention.

Drawings

Fig. 1 shows an exploded view of a system comprising a rotor shaft and an output shaft according to a first preferred embodiment of the present invention.

Fig. 2 shows the system of fig. 1 in the installed state.

Fig. 3 shows a cross-sectional view of the system of fig. 1 and 2.

Fig. 4 shows a cross-sectional view of a system comprising a rotor shaft and a transition element according to a second preferred embodiment of the invention.

Detailed Description

In fig. 1 to 3, a system 1 according to a first preferred embodiment of the present invention is shown, the system 1 comprising a rotor shaft 20 and an output shaft 10. Fig. 1 shows an exploded view of the system 1, fig. 2 shows an assembled state of the system 1, and fig. 3 shows a cross-sectional view of the assembled system 1. For example, the rotor shaft 20 is a basic component of an electric machine used in, for example, a hybrid engine of a vehicle. In order to transmit the rotational torque of the rotor shaft 20, an output shaft 10 is preferably provided on the rotor shaft 20. Here, the output shaft 10 is directly connected to the rotor shaft 20 along a longitudinal direction L extending parallel to the rotation axis R. The output shaft 10 has a base body 11 extending in the longitudinal direction L. The base 11 terminates at a first end face S1 and a second end face S2 when viewed in the longitudinal direction L. Thus, in the mounted state, the first end face S1 faces the rotor shaft 20 and preferably abuts the rotor shaft 20 in the longitudinal direction L. In particular, the first end surface S1 forms an interface for connecting the output shaft 10 and the rotor shaft 20. For this purpose, a first toothing 31 is preferably provided on the first end face S1, the first toothing 31 meshing with the complementary rotor shaft-side toothing 33 in the installed state. Thus, the first tooth 31 may be formed entirely on the first end surface S1 (i.e., formed entirely on the first end surface S1), or partially on the first end surface S1. For example, the proportion of the first tooth 31 to the total area of the first end face S1 has a value of between 25% and 100%, preferably between 40% and 90%, and particularly preferably between 60% and 80%. For example, it is also conceivable for the first toothing 31 to be formed along one ring or along a plurality of rings arranged concentrically to one another. For example, the at least one connection region 34 of the rotor shaft 20 is formed hollow in order to further reduce the weight of the system 1.

Furthermore, a side surface M, in particular a substantially cylindrical side surface M, is formed between the first end surface S1 and the second end surface S2 along the longitudinal direction L. A second tooth portion 32 is formed on the side surface M, and the second tooth portion 32 is provided for transmitting or transmitting the torque of the output shaft 10 to another consumer. Here, the second tooth 32 is preferably radially distant from the side face M. Particularly preferably, the second toothing 32 is formed as a helical toothing

Here, the tooth tips of the individual teeth extend substantially parallel to one another, wherein the tooth tips extending longitudinally between the first end face S1 and the second end face S2 are inclined with respect to the rotational axis R or the longitudinal direction L, preferably form a helix angle of between 0 and 45 °, preferably between 5 ° and 35 ° and particularly preferably between 10 ° and 25 °. Furthermore, the second tooth portion 32 does not extend over the total length L2 of the output shaft 10 measured in the longitudinal direction L. Preferably, the ratio of the first length L1 of the second tooth 32 measured in the longitudinal direction L to the total length L2 is between 0.3 and 0.8, preferably between 0.4 and 0.75, and particularly preferably between 0.45 and 0.55. Further, the second tooth portion 32 is offset from the first end surface S1 by the first pitch a1 when viewed in the longitudinal direction L. In this case, for example, the ratio of the first distance a1 to the total length L2 of the output shaft 10 measured in the longitudinal direction L is between 0.2 and 0.5, preferably between 0.3 and 0.45, and particularly preferably between 0.3 and 0.4.

Furthermore, in the mounted state, the side face M of the output shaft 10 merges flush with the outer side 21 of the rotor shaft 20, in particular in the region of the first end face S1, when viewed in the longitudinal direction L. It is thus conceivable that the output shaft 10 and the rotor shaft 20 advantageously form a common bearing region. Alternatively, the bearing region is formed only in the connection region 34 of the rotor shaft 20.

In particular, the output shaft 10 and its first and

second toothing

31, 32 are manufactured in one piece, preferably in a common forming process (in particular a forging process). Preferably, the output shaft 10 and its first and

second toothing

31, 32 are made of the same metal. Preferably, the first toothing 31, in particular as a face toothing (Hirthverzahnung), is produced using the "net shape" technique, and the second toothing 32, in particular as a helical toothing, is produced using the "near net shape" technique, and is then converted into the final shape by machining.

In addition to the output shaft 10 and the rotor shaft 20, the system 1 preferably comprises a fastener 30 which, in the mounted state, passes through the hole 15 in the output shaft 10, starting from the second end face S2. For example, the fastener 30 is a bolt that passes through the hole 15 in the output shaft 10, protrudes from the first end surface S1, and is threadedly engaged with the rotor shaft side in the rotor shaft 20 with its thread. In particular, the fastener 30 comprises a head element 38 (e.g. a screw head), wherein the output shaft 10 is clamped between the rotor shaft 20 and the head element 38 in the mounted state. Here, the head element 38 abuts against a contact face 39 of the output shaft 10, which contact face 39 is formed on the second end face S2 of the output shaft 10 in the embodiment shown in fig. 1 to 3.

Fig. 4 shows a system 1 comprising a rotor shaft 20 and an output shaft 10 according to a second preferred embodiment of the invention. The output shaft 10 in fig. 4 differs from the embodiment of fig. 1 to 3 substantially as follows: the contact surface 39 is not part of the second end surface S2, but is recessed with respect to the second end surface S2 toward the first end surface S1, in particular arranged in the base body 11. Thus, a shorter fastener 30 may be used than in the embodiment of fig. 1-3. In particular, the inner side of the hole 15 is designed such that the hole cross-section gradually narrows when viewed in the longitudinal direction L. In the example shown, the inner side is designed step-like so as to form a contact surface 39 substantially perpendicular to the longitudinal direction L. However, it is also conceivable for the contact surface 39 to be designed conical or inclined, and for the head element 38 to be sunk into such a conical contact surface 39 in the mounted state. Furthermore, a recess 37 is preferably embedded in the head element 38, in which recess 37 a corresponding tool can be engaged in order to fix or tighten the fastener 30. For example, the fastener 30 is a hexagon socket head bolt. Thus, no additional nut need be inserted into the bore 15 to secure or tighten the fastener 30 during installation.

Furthermore, a second distance a2 measured in the longitudinal direction L is provided between the first end face S1 and the contact face 39, wherein the ratio between the second distance a2 and the first distance a1 has a value of between 0.7 and 1.3, preferably between 0.8 and 1.2, particularly preferably between 0.9 and 1.1. That is, the contact face 39 is located at substantially the same height as the end of the second tooth 32 facing the first end face S1, as seen in the longitudinal direction L.

List of reference numerals

1 System

10 output shaft

11 base body

15 holes

20 rotor shaft

21 outer side

30 fastener

31 first tooth

32 second tooth part

33 rotor shaft side tooth part

34 connection region

37 groove

38 head element

39 contact surface

S1 first end face

S2 second end face

R rotating shaft

L longitudinal direction

L1 first length

Total length of L2

A1 first pitch

A2 second pitch

M side

Claims

1. A system (1) comprising a drive shaft (10) and a rotor shaft (20), the drive shaft being connectable to the rotor shaft (20), the drive shaft comprising:

a base body (11) extending along a longitudinal direction (L), the base body having:

-a first end face (S1) and a second end face (S2), and

a side face (M) extending between the first end face (S1) and the second end face (S2) when seen in the longitudinal direction (L),

characterized in that a first tooth (31) for connection to the rotor shaft (20) is formed on the first end face (S1), and a second tooth (32) for transmitting the torque is formed on the side face (M).

2. System (1) according to claim 1, wherein the first teeth (31) are face teeth.

3. System according to claim 1 or 2, wherein the second toothing (32) is a bevelled toothing.

4. System (1) according to claim 1 or 2, wherein the drive shaft (10) is integral.

5. The system (1) according to claim 1 or 2, wherein the drive shaft (10) has a hole (15) between the first end face (S1) and the second end face (S2), through which hole a fastener (30) passes in a mounted state of the drive shaft (10).

6. System (1) according to claim 5, wherein said holes are formed concentrically to said side (M).

7. System (1) according to claim 1 or 2, wherein the second toothing (32) extends over a first length (L1) when seen in the longitudinal direction (L), wherein the ratio of the first length (L1) to the total length (L2) of the drive shaft (10) measured in the longitudinal direction (L) has a value between 0.3 and 0.8.

8. The system (1) according to claim 7, wherein the ratio of the first length (L1) to the total length (L2) has a value between 0.4 and 0.75.

9. The system (1) according to claim 8, wherein the ratio of the first length (L1) to the total length (L2) has a value between 0.45 and 0.55.

10. System (1) according to claim 1 or 2, wherein the second toothing is spaced from the first end face (S1) by a first spacing (A1) when seen in the longitudinal direction (L), wherein the ratio of the first spacing (A1) to the total length (L2) of the drive shaft (10) measured in the longitudinal direction (L) has a value between 0.2 and 0.5.

11. The system (1) according to claim 10, wherein the ratio of the first spacing (a1) to the total length (L2) has a value between 0.3 and 0.45.

12. The system (1) according to claim 11, wherein the ratio of the first spacing (a1) to the total length (L2) has a value between 0.3 and 0.4.

13. System (1) according to claim 10, wherein a contact face (39) for a head element (38) of the fastener (30) is formed in the base body (11).

14. The system (1) according to claim 13, wherein a ratio of a second spacing (a2) between the contact face (39) and the first end face (S1), measured in the longitudinal direction (L), to the first spacing (a1) has a value between 0.7 and 1.3.

15. The system (1) according to claim 14, wherein the ratio of the second pitch (a2) to the first pitch (a1) has a value between 0.8 and 1.2.

16. The system (1) according to claim 15, wherein the ratio of the second pitch (a2) to the first pitch (a1) has a value between 0.9 and 1.1.

17. The system (1) according to claim 1 or 2, wherein the rotor shaft (20) is a rotor shaft (20) of an electrical machine.

18. A drive shaft (10) for a system (1) according to any one of the preceding claims.

19. Method for manufacturing a system (1) comprising a drive shaft (10) and a rotor shaft (20) according to any one of claims 1 to 17, wherein the drive shaft (10) is manufactured by a moulding process.

20. The method of claim 19, wherein the forming process is forging.

21. Method according to claim 19 or 20, wherein the first tooth (31) and the second tooth (32) are manufactured by the forming process.