EP2178428A2

EP2178428A2 - Process for producing a drive shaft

Info

Publication number: EP2178428A2
Application number: EP08802945A
Authority: EP
Inventors: Roman Sabec; Jurij Pesec; Aleksander Oblak
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2007-08-14
Filing date: 2008-07-30
Publication date: 2010-04-28
Also published as: DE102007038370A1; WO2009021843A2; DE102007038370B4; US20110200405A1; WO2009021843A3; US8651779B2

Abstract

In a process for producing a shaft (1), in particular the drive shaft of a food processor, having an end-side, splined-shaft-like toothing (3) which can be moved into positively locking engagement with a complementarily formed clutch (2), the toothing is produced by machining the drive shaft by means of a milling cutter (10). According to the invention, it is provided that the milling cutter (10) acts on the shaft (1) substantially from the radial direction with respect to the longitudinal axis of the shaft. The process according to the invention makes it possible to easily provide a more symmetrical toothing (3) of the shaft (1). The invention makes it possible to provide a food processor which operates particularly smoothly and with little vibration.

Description

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Method for producing a drive shaft

description

Background of the invention

The invention relates to a method for producing a shaft, in particular the drive shaft of a food processor, with an end-side, spline-like toothing, which can be brought into positive engagement with a complementarily shaped coupling, wherein the toothing is produced by machining the drive shaft by means of a milling cutter, and a food processor with a coupling, in which a provided with a splined toothing, shaft, preferably a drive shaft, can be used in positive engagement.

State of the art

A generic food processor is described in the document DE 35 32 038 C2. The prior art food processor has a vertical drive shaft, which is at its lower end in operative connection with an electric drive. The upper end of the drive shaft is provided with a splined toothing on which the complementarily shaped coupling of a disc-like tool can be placed.

From practice it is known to manufacture the teeth of such waves by machining the shaft. For this purpose, a cylindrical milling cutter is guided through the material of the shaft, wherein its radial surface moves along a wall of the toothing and the axial surface along the adjacent wall of the toothing. The axis of rotation of the milling cutter is perpendicular to a wall to be machined, aligned parallel to the other wall and offset from the longitudinal axis of the shaft, so that one wall on the end face and the other on the peripheral surface of the cutter. Small displacements of the axis of rotation of the milling cutter relative to the longitudinal axis of the shaft, in particular due to the unfavorable - -

The introduction of force from the cutter into the shaft results in considerable asymmetrical shape deviations of the teeth. During later insertion of the shaft into the coupling, which is usually designed with a marked excess, such teeth tend to displace the longitudinal axis of the shaft relative to the longitudinal axis of the coupling from a coaxial orientation, with the result that vibrations and run-out occur when operating the food processor can.

The problem underlying the invention

The invention has for its object to provide an improved method for producing a shaft, in particular for a food processor, as well as an improved food processor .. When operating the wave produced with the improved process and the improved food processor should also without deliberately adjusting the clutch low-vibration and smooth running.

Inventive solution

The object is achieved by methods of the type mentioned above with the features of claim 1. The fact that the cutter, relative to the longitudinal axis of the shaft, in

Essentially attacks from the radial direction of the shaft (1), the introduction of force into the shaft takes place symmetrically to the forming this Verzahnungsflanken. With the

The invention is achievable in that the shaft is less prone to dodge asymmetrically relative to the cutter. Likewise, form tolerances of the teeth are smaller for possible positional deviations of the milling cutter.

In a generic food processor, the object is further achieved in that in the transmission of torque, the positively acting contact areas between the toothing and the complementary recess of the coupling are arranged substantially on an axis of the coupling equidistantly surrounding cylinder jacket surface. - -

Preferred embodiment of the invention

Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

In a preferred embodiment of the invention, the axis of rotation (13) of the milling cutter (10) is inclined relative to the machined walls (6, 6 ') of the toothing (3). When carrying out the method according to the invention, the axis of rotation of the milling cutter is advantageously inclined with respect to the radial extent of the machined walls of the toothing by an angle which essentially corresponds to half the opening angle of the toothing. In a cross-shaped toothing with mutually perpendicular Verzahnungswandungen the inclination angle of the milling cutter is therefore preferably 45 °.

According to a preferred embodiment of the invention, the axis of rotation of the milling cutter is positioned outside the shaft to be machined. The tool is designed as a side milling cutter with a V-shaped radial surface, in which the cutting edges are incorporated.

According to an alternative method, the axis of rotation of the milling cutter is positioned crossing with respect to the longitudinal axis of the shaft. In a preferred variant of this

Method, the axis of rotation of the cutter is aligned orthogonal to the longitudinal axis of the shaft. The preferably used end mill runs at its free

End tapered to, the cone tip can be made rounded. In another variant of the method, the longitudinal axis of the milling cutter is inclined to the longitudinal axis of the shaft in such a way that the two axes enclose an angle of less than 90 °, preferably between 15 ° and 75 °, particularly preferably between 30 ° and 60 °, more preferably substantially 45 °. In this variant of the method, the milling cutter is preferably in cylindrical milling cutters. The cross section of the groove is substantially elliptical and is determined by the angle of inclination of the axes to one another and the diameter of the milling cutter.

In a preferred embodiment of the method according to the invention, the milling cutter is guided in the longitudinal direction of the shaft so that it has a longitudinal groove in the peripheral surface of the shaft - -

formed. By attaching a plurality of longitudinal grooves on the peripheral surface of the teeth of the teeth are created in the areas between the longitudinal grooves. Preferably, a shaft is provided with four longitudinal grooves, but other embodiments of the invention are conceivable, in particular the formation of 3 or 5 longitudinal grooves.

In the kitchen appliance designed according to the invention, the profile of the toothing of the shaft and the complementary recess of the coupling are in particular approximately cross-shaped. Moreover, this toothing, which is particularly easy to produce using the method according to the invention, is sufficiently robust and insensitive to soiling for use in the kitchen.

The mechanical strength and the cleaning behavior can be further improved by a rounding of the groove base of the toothing, wherein the radius of the groove bottom, for example, 0.05 times to 0.2 times, more preferably about 0.125 times the outer diameter of the toothing. If the rounding of the groove base extends far radially outwards, the orientation of the walls in the sense of the present invention is to be understood as the tangents to the radially outer point of the walls.

The inner diameter of the toothing, which forms the groove base, is advantageously 0.5 times to 0.75 times, in particular 0.625 times, the outer diameter of the toothing.

The constructive predetermined game between teeth of the shaft and recess of the coupling is further designed according to an advantageous embodiment of the invention that the toothing of the shaft when transmitting a torque against the complementary, formed with excess recess of the coupling along the common longitudinal axis by an angle of 15 ° to 20 °, preferably about 17.5 ° turned is aligned. As a result, in addition to a speedy self-centering of the shaft in the coupling easy joining even with impurities in the coupling area causes. - -

Brief description of the drawings

The invention is explained in more detail below with reference to schematic drawings of an exemplary embodiment with further details.

Show it:

Fig. 1: a side view of an inventively designed coupling portion with a longitudinally-cut coupling in design position;

2 shows a cross section A-A through the coupling region shown in FIG

Design position;

FIG. 3 shows the cross section according to FIG. 2 immediately after the shaft has been joined into the coupling; FIG.

4 shows the cross section according to FIGS. 2 and 3 during the transmission of a torque;

5 shows an enlarged detail of the illustration according to FIG. 4;

Fig. 6: the production of a toothing according to the prior art;

FIG. 7 shows a first method according to the invention for producing the toothing; FIG.

Fig. 8: a manufacturing method according to another embodiment of the invention.

Detailed description based on embodiments

In the following description of preferred embodiments of the present invention, like reference characters designate like or similar components. - -

As shown in FIGS. 1 and 2, the transmission of the drive torque to the shaft 1, which is in operative connection with a tool, also not shown, from a motor, not shown, of the food processor into a clutch 2. The shaft 1 is at her in the coupling 2 insertable end provided with extending in the longitudinal direction, a cross-shaped toothing 3, which in a complementary, but enlarged recess 4 of the clutch 2 can be used. In the design position of the coupling region, the shaft 1 is spaced from the coupling 2 by an approximately equidistantly extending radial gap 5. With an outer diameter D of the shaft 1, for example, 12 mm, the gap width s, for example, be 1, 5 mm. The adjoining walls 6, 6 'of the toothing 3 are aligned approximately at right angles to each other and go into each other in a generously rounded groove bottom 7.

When inserting the shaft 1 into the coupling 2, an eccentric alignment of the longitudinal axis 8 of the shaft 1 with respect to the longitudinal axis 9 of the coupling 2 will generally set (FIG. 3). Due to the generously dimensioned in design position radial gap 5 joining is easily possible even in case of any form or positional deviations of these components and their contamination. When a torque M is introduced into the shaft 1, centering of the shaft 1 in the clutch 2 takes place immediately, as shown in FIG. 4. The contact areas P between the toothing 3 of the shaft 1 and the recess 4 of the coupling 2 are then, as can be seen from FIG. 5, arranged on a cylinder jacket surface Z surrounding the longitudinal axis of the coupling 2.

In the production of gears for drive shafts of food processors according to the prior art shown in Fig. 6, a cylindrical cutter 10 is guided along the shaft 1 that its end face 11 at least partially on the wall 6 'and its peripheral surface 12 partially on the wall 6 abut. The axis of rotation 13 is offset relative to the longitudinal axis 8 of the shaft 1 and to the walls 6, 6 'aligned in parallel or at right angles and is moved in the longitudinal direction. The finger-like cutter 10 tends to deviate from the desired milling position by bending. Likewise already introduces - -

low error in the alignment of the cutter 10 to a very asymmetrical formation of the teeth. 3

By contrast, when the method according to the invention is exercised, the axis of rotation 13 of the milling cutter 10 is inclined relative to the walls 6, 6 ', the angle of inclination α being 45 ° in the case of the teeth 3 shown at right angles to one another in the embodiments 6 and 6'. As shown in Fig. 7, the cutter 10 may be formed like a disk with V-shaped peripheral surface 12, wherein the axis of rotation 13 offset from the longitudinal axis 8 of the shaft 1 and out of the cross section of the shaft 1 is aligned, from the cutter 10 to the shaft 1 exerted force F, however, defined in the direction of the longitudinal axis 8 extends.

Alternatively, in the production of the teeth 3, a cutter 10 with a conical end face 1 1 are used (Fig. 8), the axis of rotation 13 is also inclined by an angle α of 45 ° relative to the walls 6, 6 ', but in the direction of the longitudinal axis 8 of the shaft 1 is aligned.

With the method according to the invention, a more symmetrical toothing 3 of the shaft 1 can be created in a simple manner. By the invention, a food processor can be provided with a particularly low-vibration and quiet running.

The features disclosed in the foregoing description, the claims and the drawings may be of importance both individually and in any combination for the realization of the invention in its various forms.

Claims

- Patent claims

1. A method for producing a shaft (1), in particular the drive shaft of a food processor, with an end, splined toothing (3) which can be brought into positive engagement with a complementarily shaped coupling (2), wherein the teeth by machining the

Drive shaft by means of a cutter (10) is made, characterized in that the cutter (10) substantially from the radial direction with respect to the longitudinal axis of the shaft to the shaft (1) engages.

2. The method according to claim 1, characterized in that the rotational axis (13) of the cutter (10) relative to the machined walls (6, 6 ') of the toothing (3) is aligned inclined.

3. The method according to claim 1 or 2, characterized in that the axis of rotation (13) of the milling cutter 10) relative to the radial extent of the machined walls (6, 6 ') of the teeth (3) is inclined substantially at half its opening angle.

4. The method according to any one of the preceding claims, characterized in that the axis of rotation (13) of the cutter (10) outside of the shaft to be machined

(10) is progressively positioned.

5. The method according to any one of the preceding claims, characterized in that the axis of rotation (13) of the cutter (10), the longitudinal axis (8) of the shaft (1) is positioned crossing.

6. The method according to claim 5, characterized in that the rotational axis (13) of the cutter (10) orthogonal to the longitudinal axis (8) of the shaft (1) is aligned. - -

7. Food processor with a coupling (2), in which a with a splined toothing (3) provided, in particular according to one of claims 1 to 5 manufactured shaft (1), preferably a drive shaft, is inserted in positive engagement, characterized in that in the transmission of a torque (M) the positively acting contact areas (P) between the toothing (3) and the complementary recess (4) of

Coupling (2) substantially on a longitudinal axis (9) of the recess (2) equidistantly surrounding cylinder jacket surface (Z) are arranged.

8. Food processor according to claim 7, characterized in that the profile of the toothing (3) of the shaft (1) and the complementary recess (4) of the

Clutch (2) are formed approximately cross-shaped.

9. Food processor according to claim 7 or 8, characterized in that the groove base (7) of the toothing (3) is rounded.

10. Food processor according to claim 9, characterized in that the radius of the groove bottom (7) is 0.05 times to 0.2 times, in particular about 0.125 times the outer diameter (D) of the toothing (3).

11. Food processor according to claim 9 or 10, characterized in that the groove base (7) forming inner diameter (d) of the toothing is 0.5 times to 0.75 times, in particular 0.625 times the outer diameter (D) of the toothing (3) ,

12. Food processor according to one of claims 7 to 1 1, characterized in that the toothing (3) of the shaft (1) upon transmission of a torque (M) relative to the complementary, formed with excess recess (4) of the coupling (2) along the longitudinal axes (8, 9) is aligned by an angle (ß) of 15 ° to 20 °, preferably about 17.5 °.