DE9407975U1 - Shift rail - Google Patents

Description

Kochendörfer & Kiep

Punching and fine punching plant GmbH
Maybachstrasse 3
78467 Constance

Shift rail

The invention relates to a shift rail for a manual transmission for transmitting the movement of a shift finger on a shift lever to a shift sleeve via an engagement fork.

When manufacturing manual transmissions for cars, for example, the very tight conditions within a manual transmission must be taken into account. There is very little space available for the individual transmission elements, which means that the elements are very closely nested within one another and therefore have very irregular contours. Even today, shift rails of the type mentioned above are manufactured as cast parts, with bearing points on both sides requiring complex machining. This subsequent machining is disadvantageous because it takes a considerable amount of time and also requires subsequent, complex checking of the correct fit. Furthermore, the shape of the rails made from a cast part cannot be changed later.

The present invention is based on the object of creating a shift rail of the above-mentioned type, the manufacture of which is significantly simplified.

This task is solved by having strips protrude from both sides of a central part with a recess for accommodating a shift finger, with both ends of the strips being overmolded with plastic and this plastic forming bearing points.

This means that the time-consuming work of working out bearing points is no longer necessary and at the same time the plastic or the bearing points are very well secured to the strips. The retention of the bearing points on the strips is further improved by the fact that the strips have constrictions into which the plastic flows during injection molding. The plastic then forms locking lugs with the constrictions.

During the injection molding process of the plastic, it is now also possible according to the invention to assign additional functions to the bearing points that were previously only performed by the metal base body.

This primarily means that the engagement fork itself is made of plastic. This is done during the production of one of the bearing points by injection molding in the corresponding injection mold. The bearing points and engagement fork are a single piece, with this engagement fork later engaging in a selector shaft. The engagement fork also serves to prevent rotation.

Preferably, the base body, consisting of the middle part and the two strips, is formed from a sheet metal part. The sheet metal part has the advantage that it can be formed easily by folding, cranking or bending. Here

Very precise dimensions can be maintained or inaccuracies can be corrected. In the present example, the two side strips are bent away from the middle part. This is a very simple manufacturing process.

Furthermore, the base body can be inductively hardened before or after forming. This increases its strength, as does the use of steel as the material for the base body.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing, which shows in
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Figure 1 shows a cross section through a shift rail according to the invention;

Figure 2 is a plan view of the shift rail according to Figure 1;

Figure 3 shows a section through the shift rail according to Figure 1 along line III-III;

Figure 4 shows a cross section through the shift rail according to Figure 1 along line IV-IV.

A shift rail R according to the invention has a base body 1, preferably made of sheet metal, according to Figures 1 and 2. This base body 1 has a middle part 2 with a recess 3 for receiving a shift finger 4 indicated in Figure 2. On both sides of this middle part 2, strips 5 and 6 are formed, onto which bearing points 7 and 8 made of plastic are injection-molded. To better hold the bearing points 7 and 8 on the strips 5 and 6, the strips 5 and 6 each have constrictions 9 and 10 on both sides, which are also filled with plastic after the injection-mold process for the bearing points 7 and 8. Otherwise, both ends of the strips 5 and 6 are completely surrounded by the plastic.

The bearing point 8 also has an obliquely running flattened portion 11 produced during the injection molding process, which is shown in more detail in Figure 3.
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At the opposite bearing point 7, an engagement fork 12 is formed, which is used to transmit a

• · — You- · ···

Switching movement to a shift sleeve not shown in detail

a corresponding manual transmission and anti-twisting device

The engagement fork is more clearly visible in Figure 4.

The strips 5 and 6 are bent upwards from the middle part 2, as can be seen in Figure 1. Furthermore, the recess 3 has an inner contour that is adapted to the function of the shift finger 4. Therefore, a more detailed description is omitted.

Claims (6)

PROTECTION CLAIMS 1. Shift rail for a manual transmission for transmitting the movement of a shift finger (4) on a shift lever to a shift sleeve via an engagement fork (12), characterized, that strips (5, 6) protrude from both sides of a central part (2) with a recess (3) for receiving a shift finger (4), both ends of the strips (5, 6) being overmolded with plastic and this plastic forming bearing points (7, 8). 2. Shift rail according to claim 1, characterized in that the strips (5, 6) have constrictions (9, 10) which are also filled with the plastic. 3. Shift rail according to claim 1 or 2, characterized in that a bearing point (8) has an obliquely extending flattening (11). 4. Shift rail according to one of claims 1 to 3, characterized in that the engagement fork (12) is connected in one piece to the bearing point (7). 5. Shift rail according to one of claims 1 to 4, characterized in that the middle part (2) together with the strip (5, 6) is formed in one piece from a sheet metal. 6. Shift rail according to claim 5, characterized in that the strips (5, 6) are bent in front of the central part (2).