DE102020122668A1 - transmission component - Google Patents

Abstract

The invention relates to a transmission component (1) with a shaft section (2) and a hub section (3), the shaft section (2) and the hub section (3) having a radial shape (7a) in the radial direction and an axial shape (7a) in the axial direction 5) are positively connected to one another, with both the radial shape (4) and the axial shape (5) being non-circular in the circumferential direction.

Description

The invention relates to a transmission component with a shaft section and a hub section connected to it in a form-fitting manner.

In transmissions, components are used in which a power flow occurs between a shaft and a hub during operation. Shaft-hub connections are subject to high requirements in terms of their moment strength as well as their manufacture and assembly.

the EP 3 263 936 B1 shows a shaft-hub connection with a spline. A spline is a multiple driver connection. The torques are usually transmitted by the tooth flanks. The shaft is splined on the outside and the hub is splined on the inside. Drivers protrude outside of the shaft or inside of the hub. Corresponding recesses are then located on the respectively opposite element. Such splines are known as involute, parallel or serrations, depending on the formation and contour of the teeth. Key splines, round press connections or other connections with intermediate elements are very common in conventional shaft-hub connections. The contact contour required for torque transmission is to be ensured by the intermediate elements. Other fitting connections known in the prior art also have carriers with polygonal outer contours, which include, for example, the so-called H or P3G profiles. The connections have a full-surface form fit.

A shaft-hub connection with polygon shapes of the shaft and hub, where the polygon is a hypotrochoid or is composed of hypotrochoid sections, is made of DE 10 2004 004 456 A1 famous.

The invention is based on the object of proposing a transmission component which, with a high torque robustness, has advantages during manufacture and assembly.

This object is achieved by a transmission component having the features of claim 1. Preferred or advantageous embodiments of the invention result from the dependent claims, the following description and the attached figures.

The invention is based on the finding that, contrary to popular belief, a form-fitting shaft-hub connection can be advantageous not only in terms of particularly high torque strength but also in terms of cost-effective manufacture and assembly. This applies in any case if welding can be completely dispensed with when making the connection. A form fit both for forces in the circumferential direction and for an axial force effect creates such a connection, with a non-round contour of the radial shape producing the form fit in the circumferential direction and the axial shape producing the form fit in the axial direction being provided on the one hand. These out-of-roundnesses are now offset from one another in such a way that an axial stop is formed in a simple and space-saving manner. “Out of round” here means that a respective contour of the radial and axial shape does not have a constant radial distance to the axis of the shaft-hub connection over the circumference. There is thus in particular a smallest and a largest radial distance.

Preferably, the radial shape runs along its contact surface forming the form fit with a contour whose curvature is essentially constant, with the contour being more preferably designed as a complex trochoid. A particularly favorable introduction of force is produced by such a contour, since the continuous contour entails particularly low notch forces. “Constant” here means that the contour does not show such a strong local change in its radius of curvature that it could be described as erratic when considering the dimension of the transmission component. A contour that corresponds to a complex trochoid is particularly favorable for a continuous course. A contour in the form of a trochoid arises with the locus of a point on a circle, which runs on the circumference of another circle (inside or outside), whereby this locus can be compressed or stretched in the running direction. If further eccentricities are built in, a complex trochoid results.

The axial shape is preferably offset with its out-of-roundness compared to the out-of-roundness of the radial shape in the circumferential direction such that a maximum radius of the out-of-roundness of the axial shape is opposite a minimum radius of the out-of-roundness of the radial shape.
In this way, a radial overhang of the axial shape with respect to the radial shape for the shaft section is formed on the hub section and thus the axial form fit is formed in a first axial direction.

More preferably, an axial fixation of the shaft section relative to the hub section in a second axial direction, opposite the first axial direction, is realized by caulking.

The radial shape on the hub side is preferably stamped or fine-blanked, while the radial shape on the shaft side is machined. The radial shape has the contour that creates the form fit. The contact surface runs along this contour running in the circumferential direction in an axial extension, which lies in the positive fit of the shaft section and hub section. The shaft and hub sections therefore each have a mutually directed, uniform contact surface.

Machining a surface with a complex shape is typically complex and expensive in terms of manufacturing technology. A shaft-hub connection is therefore often joined and welded with a very simple contact surface. According to the knowledge of the invention, however, the manufacturing process for the transmission component can be designed more favorably overall if further processing of the shaft is completed in a single clamping process. Together with a higher machine flexibility of a machine that works by cutting, there are surprisingly high overall economic advantages, which make the machining process, which is expensive per se, advantageous for the shaft section. The contact surface on the hub portion can then be made by cheap stamping or fine blanking.

With this manufacturing strategy, a complex form fit with its favorable torque introduction can now also be used for a transmission component for which this was typically not an option for cost reasons. In particular, the transmission component is suitable for a planetary gear in an electric drive train of a motor vehicle.

• 1 Eine Aufsicht auf Getriebekomponente
• 2 Eine 3d-Ansicht einer Getriebekomponente eines Planetengetriebes
• 3 einen Schnitt entlang der Achse der Getriebekomponente aus 3
• 4,5 3d Ansichten eines Wellenabschnitts einer Getriebekomponente

Further features, advantages and effects of the invention result from the following description of a preferred exemplary embodiment of the invention and the attached figures. show:

• 1 A top view of transmission component
• 2 A 3d view of a gear component of a planetary gear
• 3 Cut out a section along the axis of the transmission component 3
• 4 , 5 3d views of a shaft section of a transmission component

the 1 shows a plan view of a transmission component 1, comprising a shaft section 2 and a hub section 3. The shaft section 2 and the hub section 3 are positively connected in the circumferential direction by a radial shape 4. The radial form 4 runs in the circumferential direction in the contour of a complex trochoid. A form fit is also produced in an axial direction between the shaft section 2 and the hub section 3, specifically by means of an axial mold 5.

Both the radial shape 4 and the axial shape 5 are non-circular, ie they run in the circumferential direction along a contour whose points are not all at the same distance from an axis Z of the shaft section 2 . Then the contour would be circular, i.e. round. Thus, the radial shape has 4 points at the smallest distance from the axis Z, ie a minimum radius 8a, and points at the greatest distance, ie a maximum radius 8b. The axial form 5 has points at the smallest distance from the axis Z, ie a minimum radius 7a, and points at the greatest distance, ie a maximum radius 7b. The points with the minimum radius 8a of the radial shape 4 face points with the maximum radius 7b of the axial shape 4 in the circumferential direction. Thus, points with a maximum radius 8b of the radial shape 4 also face points with a minimum radius 7b of the axial shape 4 in the circumferential direction. As a result, an axial stop 9 is formed, which represents an axial form fit between the shaft section 2 and the hub section 3 . This is explained in more detail using the 2 and 3 explained.

2 shows a 3d view of a transmission component 1 designed as a planetary carrier with a shaft section 2 and a hub section 3. A section along the Z axis of the shaft section 2 is shown in FIG 3 shown. It is clear here how the different recesses of the respective contours of the radial shape 4 and axial shape 5 in the circumferential direction form an axial stop 9 which forms a positive fit between the shaft section 2 and the hub section 3 in a first axial direction. In a second axial direction, which is opposite to the first axial direction, an axial fixation is achieved in that a material section 10 of the shaft section 2 is calked with a calking force V to the hub section 3 .

the 4 and 5 show views of the shaft section 2 with the radial shape 4 and the axial shape 5.

Reference List

1

transmission component

2

wave section

3

hub section

4

radial shape

5

axial shape

6

housing

7a

maximum radius axial form

7b

minimum radius axial shape

8a

maximum radius radial shape

8b

minimum radius radial shape

9

Projection / axial stop

Z

axis

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 3263936 B1 [0003]
• DE 102004004456 A1 [0004]

Claims (8)

Transmission component (1) with a shaft section (2) and a hub section (3), the shaft section (2) and the hub section (3) being positively connected to one another in the radial direction by a radial shape (7a) and in the axial direction by an axial shape (5). are connected, both the radial shape (4) and the axial shape (5) are non-circular in the circumferential direction. Transmission component (1) after claim 1 , characterized in that the radial shape (4) runs along its form-fitting contact surface with a contour whose curvature is substantially constant. Transmission component (1) after claim 2 , in which the contour is formed as a complex trochoid. Transmission component (1) according to one of the preceding claims, in which the axial shape (5) with its out-of-roundness is offset relative to the out-of-roundness of the radial shape (4) in the circumferential direction such that a maximum radius (7a) of the out-of-roundness of the axial shape (5) corresponds to a minimum Radius (8a) faces the out-of-roundness of the radial shape (4). Transmission component (1) after claim 4 , in which a radial overhang (9) of the axial shape (5) relative to the radial shape (4) forms an axial stop (9) for the shaft section (2) on the hub section (3) and thus the axial form fit in a first axial direction. Transmission component (1) after claim 5 , in which an axial fixation of the shaft section (2) relative to the hub section (3) in a second axial direction opposite to the first axial direction is realized by caulking. Transmission component (1) according to one of the preceding claims, in which the radial shape (4) is stamped or fine-blanked on the hub side, while the radial shape (4) is machined on the shaft side. Planetary gear with a gear component (1) according to one of the preceding claims.

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