WO2001071222A1

WO2001071222A1 - Non-machined shift lever

Info

Publication number: WO2001071222A1
Application number: PCT/EP2001/001665
Authority: WO
Inventors: Peter Jennes
Original assignee: Ina-Schaeffler Kg
Priority date: 2000-03-21
Filing date: 2001-02-15
Publication date: 2001-09-27
Also published as: DE10013878A1; DE10191073D2; DE10191073B4

Abstract

The invention relates to a shift lever (1a) for selecting gears, which is configured as one-piece and has a rotationally symmetrical shift profile (4a) and which is produced by a non-machined shaping process.

Description

Chipless shaft

Field of the Invention

The invention relates to a selector shaft which is intended for a gear shift of a gear change transmission. The shift shaft, which is displaceable and rotatable in the gear housing, enables a gear change, i.e. a gear change, with which the speed and torque of a transmission output shaft can be varied. For this purpose, the selector shaft is in operative connection with drivers or transmission elements, which preferably engage in a form-fitting manner in a selector profile or a detent profile of the selector shaft. Such circuits are common in today's vehicles and known to every driver. This gear shift can be operated either manually or automatically.

Switching shafts of the previous type are usually solid shafts with partial cutouts to show the locking profile or the switching profile. A complex and costly copy milling or contour milling is usually used for the production of this profile. These measures ensure the required position and location of the profile combs of the switching profile. The partial milling, which extends partially over the center of the shaft, causes a significant weakening, as a result of which the required strength of the selector shaft is no longer guaranteed. As a result, the selector shaft exceeds limit values for the deflection, with the result that hardness distortions occur and the selector shaft becomes unusable.

DE 198 05 924 A1 shows a section of a known transmission circuit. This circuit comprises a selector shaft, which is designed as a tubular body, a pin fixed to the transmission housing engaging in each of the two tube ends, on which the selector shaft can be rotated and axially rotated via a bearing. is slidably arranged. The selector shaft is provided with selector fingers that engage a driver for actuating a selector fork. The known control shaft, which is designed as a hollow body, is further provided with a separate locking sleeve which interacts with a ball catch arranged next to the control shaft, in order to limit the switching travel or to fix the position of a control shaft position. This known selector shaft comprises many individual parts which are permanently connected to the selector shaft by a welded connection. The welding requires a lot of effort to avoid stress cracks or to maintain the required position and shape tolerances. This disadvantageously increases the manufacturing costs of this known control shaft.

Object of the invention

Starting from the disadvantages of the known selector shaft, it is the object of the present invention to provide a selector shaft which includes inexpensive manufacture and improved strength.

Summary of the invention

To solve the aforementioned problem, the selector shaft according to the invention is provided with a switching profile or a latching profile, which comprises non-cutting, radially oriented beads and / or walls. The beads arranged in pairs axially delimit a guide groove, which can also be referred to as an annular groove, in which transmission elements arranged next to the selector shaft engage in a form-fitting manner. For example, a shift fork or a locking device can be used as the transmission element, which engages in a form-fitting manner in the guide groove.

The invention, which relates to a rotationally symmetrical, non-cutting switching shaft profile, improves the strength of the sound wave due to a material hardening that occurs in the forming process for producing the switching profile. The rotationally symmetrical arrangement of the Switching profile furthermore does not require a precise mounting of the switching shaft, which can consequently be inserted into the transmission automatically, which results in a further cost advantage.

The invention thus realizes the demand for a cost-effective production of the entire selector shaft, wherein the switching or locking profiles can be positioned at any point on the selector shaft. The invention also offers a further potential for savings, since switching shafts with different latching or switching profiles can be produced starting from a hollow body profile.

Further advantageous embodiments of the invention are the subject of dependent claims 2 to 11.

A circular kneading method is advantageously suitable for producing the switching profile according to the invention, by means of which the switching or latching profile of the switching shaft is shaped out of the wall of the hollow body by means of an informal kneading. The plastic deformation of the material during rotary kneading results in a structural change, grain stretching, combined with an increase in mechanical strength and hardness. The elastic limit is increased in the direction of loading and the microstructure changes into a kind of texture, with a favorable fiber course improving the strength especially at the points of the greatest deformation, the profile transitions. With the circular kneading process, an increase in tensile strength of approx. 20% can be achieved.

The circular kneading process is advantageously suitable for rotationally symmetrical shapes. Pipes in seamless drawn or welded design are preferably used as the starting material. In the area of cross-sectional transitions, the switching profile according to the invention is designed in such a way that sharp edges or jagged transitions are avoided. The kneading process provided for the production enables the production of switching shafts according to the invention in large numbers and in ongoing production processes. processes. The circular kneading process is therefore also suitable for large series production, as is required for selector shafts in vehicles, in particular passenger cars.

The circular kneading process enables the production of switch profiles in a quality that corresponds to fine machining, which can only be achieved with great effort during machining. Due to the structural changes that occur during the kneading process, which at the same time results in improved strength, an additional heat treatment of the control shaft can be dispensed with. The circular kneading process used to manufacture the switching profile is suitable for both external profiles and internal profiles.

The savings in material through lossless reshaping of the workpiece and the higher resistance of cold-hardened surfaces to wear and corrosion are a further advantage compared to machining the selector shaft to form the selector profile. Compared to solid solid material shift shafts, the shift shaft according to the invention, designed as a hollow body, offers a weight advantage of up to 75%.

The invention further includes hydraulic high-pressure forming for producing the selector shaft according to the invention. An internal high pressure process (IHV) is particularly suitable for this, with which almost any material forming can be achieved. This stretch forming technology, for example working with high water pressure, is suitable for free shaping in metal, but also for a predetermined contour, for example a switching profile.

The precise execution of such molded parts in the tightest tolerances can be mass-produced. Since the production is wear-free, the switching profile or the switching shaft is highly precise and does not require any rework. Hydraulic high-pressure forming is also a rational method because different radii and different The contours of the switching profile on a selector shaft can be formed in just one operation.

The invention also includes control shafts in which the switching profile is molded into the wall of the hollow body at any point. Alternatively, the switching profile can be combined with a tubular body as a separate component produced without cutting. To fasten such a switching profile, it advantageously has axial lugs arranged on both end faces or axially aligned fastening tabs arranged in sections, by means of which the separate switching profile is permanently attached to the tubular body.

The geometric design of the switching profile is preferably in the form of a trapezoidal cross section. Depending on the arrangement of the transmission elements that are adjacent to the selector shaft, the selector profile can be designed as an inner or outer profile. The non-cutting forming processes according to the invention enable both a switching profile emerging radially from the lateral surface of the hollow body and a profiling oriented in the direction of a longitudinal axis of the switching shaft. Furthermore, the invention includes a control shaft with geometrically differently configured and aligned switching profiles, i. H. In addition to a switching profile designed as an external profile, the control shaft also has an internal profile.

The non-cutting manufacturing process of the selector shaft according to the invention also extends to areas of the selector shaft which are arranged offset to the selector profile, such as a bearing seat or a bearing raceway, with which the selector shaft is rotatably and displaceably arranged in the transmission housing. Such a bearing seat can be designed, for example, as a cylindrical extension which is arranged radially offset from the rest of the outer surface of the selector shaft. The manufacturing process results in a largely identical wall thickness in all areas of the selector shaft designed according to the invention. However, the wall thickness in the cylindrical region of the selector shaft exceeds the wall thickness in the region of the selector profile.

A cold-formable metal or a cold-formable alloy is provided as the material for the selector shaft according to the invention. This can be, for example, a suitable carbon-containing steel that can be heat-treated but is also sufficiently extensible to enable it to be formed without cracking. Suitable materials are, for example, 15CR3, 32CrMo4, 38CrSiV66 or 10 S 20.

In principle, all materials can be formed well, the initial strength of which does not exceed the limit of 120 kp / mm ² . It is essential for good production results that the highest possible stretch, which is in a range of 8 to 10%.

Brief description of the drawings

Advantageous exemplary embodiments of the invention are shown in the drawings, which are described in more detail below. Show it:

Figure 1 shows a control shaft according to the invention in a half section with a radially outwardly directed switching profile;

Figure 2 shows a section of a control shaft, the switching profile is directed radially inwards;

Figure 3 shows a section of a two-part shift shaft, in which a separate switching profile is placed on a tubular body. Detailed description of the drawings

The control shaft 1a shown in a half section in FIG. 1 comprises a rotationally symmetrical hollow body 2a. A switching profile 4a, which comprises two guide grooves 5, 6, is formed in a lateral surface 3 of the hollow body 2a by a non-cutting forming process. The guide grooves 5, 6 are axially delimited by walls in the form of beads. In Figure 1, the walls 8a, 8b limit the guide groove 5 and the further guide groove 6 is laterally delimited by the walls 8b and 8c. Common to all walls 8a, 8b, 8c is a trapezoidal cross-sectional profile, which together form a profile comb 10. The geometrical design of the walls 8a, 8b, 8c with regard to the radial height and their longitudinal extent can be both the same and different, the shaping taking place as a function of the transmission element which engages in the guide groove 5a, 6a, or latches therein , Axially offset to the switching profile 4a by a cylindrical section 9, the switching shaft 1a is provided on both sides with a bearing seat 11, 12, which forms a length-limited, cylindrical receiving surface, for example for a roller bearing or a roller guide, in order to thereby cause an axial displacement and / or a rotary movement of the Enable shift shaft 1.

FIG. 2 shows a section of the control shaft 1b, the switching profile 4b of which, in contrast to the control shaft 1a, radially inwards, i. H. is oriented pointing in the direction of a longitudinal axis 13. The non-cutting forming process according to the invention also enables the production of a selector shaft 1b with a selector profile 4b designed as an inner profile, which according to FIG. 2 is provided with a total of three guide grooves 5, 6, 7, each of which has a trapezoidal shaped cross-sectional profile.

FIG. 3 shows a two-part construction of a switching shaft 1c. For this purpose, a switching profile 4c designed as a separate component is arranged on a tubular hollow body 2c. The design of the switching profile 4c corresponds to the switching profile 4a shown in FIG. 1. To attach the switching profile 4c the lateral surface 3 of the hollow body 2c is served by a preferably cylindrical extension 14, 15, which is non-detachably, preferably by means of a weld, connected to the lateral surface 3 of the hollow body 2c. As an alternative to the two-part shift shaft 1 c shown, this can also be provided with further separate shift profiles.

reference numerals

a control shaft b control shaft c control shaft a hollow body b hollow body c hollow body

Lateral surface a switching profile b switching profile c switching profile

guide

Guide groove a wall b wall c wall cylindrical section 0 profile comb 1 bearing seat 2 bearing seat 3 longitudinal axis 4 shoulder 5 shoulder

Claims

claims

1.Switching shaft for a transmission circuit of a gear change transmission, in particular a mechanically switchable gearbox, the shift shaft (1 a, 1 b, 1c) is displaceably and rotatably arranged in a transmission housing and is designed as a rotationally symmetrical, non-cutting metallic hollow body (2a, 2b, 2c) with at least a switching profile (4a, 4b, 4c) and / or a locking profile, the profile comprising a plurality of radially oriented, in particular paired and axially spaced walls (8a, 8b, 8c) which delimit a guide groove (5, 6, 7) zen, in which the control shaft (1a, 1b, 1c) has secondary transmission elements.

2. Switching shaft according to claim 1, whose switching profile (4a, 4b, 4c) is produced by means of a circular kneading process, with which the rest of the switching shaft (1a, 1b, 1c) is also designed.

3. shift shaft according to claim 1, the entire contour is produced by a hydraulic high-pressure forming.

4. Switching shaft according to claim 1, with a one-piece structure, which comprises a hollow body (4a, 4b), in the outer surface (3) of which the switching profile (4a, 4b) is introduced (FIG. 1, FIG. 2).

5. Switching shaft according to claim 1, which comprises at least two components, a hollow body (2c) to which a switching profile (4c) designed as a separate component is assigned (FIG. 3).

6. selector shaft according to claim 5, wherein the separate switching profile (4c) is provided on both sides with a cylindrical extension (14, 15) with which the switching profile (4c) is fastened to the lateral surface (3) of the hollow body (2c) (FIG. 3).

7. control shaft according to claim 1, the switching profile (4a) radially from the outer surface (3) of the switching shaft (1a) emerging walls (8a, 8b, 8c) which form a profile comb (10) (Figure 1).

8. selector shaft according to claim 1, wherein the switching profile (4b) has radially inwardly in the direction of a longitudinal axis (13) of the selector shaft (1b) aligned walls (Figure 2).

9. Switching shaft according to claim 1, which has at least one bearing seat (11, 12) which is arranged axially offset to the switching profile (1a) and radially to a lateral surface (3) of the switching shaft (1a) (Figure 1).

10. Switching shaft according to claim 1, the wall thickness in a cylindrical section (9) of the hollow body (2a) exceeds the wall thickness in the region of the switching profile (4a).

11. Switching shaft according to claim 1, the hollow body (2a, 2b, 2c) is made of a cold-formable material or a cold-formable alloy.