EP0975904A1

EP0975904A1 - Gear with central control shaft

Info

Publication number: EP0975904A1
Application number: EP98948995A
Authority: EP
Inventors: Erich Bollmann; Frank Melchers; Siegfried GÖRNITZ
Original assignee: Kochendorfer and Kiep Metallverarbeitung GmbH
Current assignee: Kochendorfer and Kiep Metallverarbeitung GmbH
Priority date: 1998-02-13
Filing date: 1998-09-30
Publication date: 2000-02-02
Also published as: DE19882218B4; WO1999041529A1; AU9541698A; DE29814943U1; DE19805924A1; DE19882218D2

Abstract

The invention relates to a gear comprising a central control shaft (2) positioned in a housing (1) and actuating elements assigned to said shaft for the axial displacement and rotation of the central control shaft (2) on which shift fingers (8, 9) are mounted for actuating shift forks (11, 13). According to the invention the central control shaft (2) consists of a tube.

Description

TRANSMISSION WITH A CENTRAL SHIFT SHAFT

The invention relates to a transmission with a central shift shaft in a housing and actuating elements associated therewith for axially displacing and rotating the central shift shaft, on which shift fingers are arranged for actuating shift forks.

Such transmissions are used in a variety of vehicles today. With them, the gear shift known to every driver takes place. This can be done either manually or automatically.

High demands are placed on such a transmission. The space requirement is very small because a circuit should have every possible comfort for the operator. Furthermore, the transmission should get by with the least possible components.

A part of such a transmission is shown for example in DE-AS 11 22 385, where it is mentioned that - 2 - The shift fork can either be actuated by a shift shaft that moves the shift rod with the attached shift fork by means of a lever, or the shift actuation can also be initiated directly into the shift fork, as is common with the so-called stick shift.

The object of the present invention is to improve a transmission of the type mentioned above in such a way that the components are minimized and made lighter and the comfort is increased.

The solution to this task is that the central control shaft consists of a tube.

So far, the central selector shaft has been made of solid material. In contrast, a tube has the advantage that, on the one hand, weight is saved, so that the diameter of the central selector shaft can be kept larger despite the reduced weight when selecting a tube. Furthermore, it is possible to provide an inner bearing of the central shift shaft in the tube, so that all bearing parts for the tube itself have already disappeared from the area of the other elements of the transmission.

The tube is preferably at least partially hardened, so that its strength is completely sufficient for its function.

Another essential idea of the present invention relates to the functional reliability of the transmission. There is an increasing demand that only one shift fork be actuated when shifting the transmission, while the other shift forks are fixed. However, such a definition is not yet known. - 3 -

According to the present invention, the shift forks are fixed by the central shaft itself. For this purpose, supports are provided on the drivers on which the shift forks are fixed, which are seated on the circumference of the central shift shaft when the shift forks are not actuated. These supports preferably lie opposite one another in a region of the elbow and, in the position of use in which they are not actuated, maintain a distance from the longitudinal axis of the central shift shaft which corresponds approximately to the radius of the central shift shaft. This means that the drivers cannot move in this position of use, so that the shift forks assigned to them are at rest.

If, on the other hand, a driver comes into a recess for actuating the shift fork, the supports also reach a region of recesses which are provided in the central shift shaft in the plane of the shift finger. This means that the supports can slide into this recess when the shift finger is moved, so that the shift fork is now able to move.

This idea of the present invention can also be used with a central shift shaft made of solid material, but should preferably be used with a central shift shaft which is designed as a tube.

Another idea of the present invention relates to an improvement in the setting options of the transmission. Settings must be made on the gearbox that relate, for example, to the arrangement of the actuating elements, the arrangement of the gear wheels, the arrangement of the shift forks, etc. In many such activities, it is desirable that the central shift shaft be fixed. - 4 -

For this purpose, a pin is provided according to the invention, which can be inserted into a hole in this central switching shaft in order to fix the central switching shaft. For the sake of simplicity, this insertion takes place against the force of a spring and upon rotation of the bolt by approximately 90 °, a transverse bolt sliding like a bayonet into a notch in a guide sleeve at the tip of a sloping surface of this guide sleeve.

To loosen the bolt and thus to release the central shift shaft, the bolt is again rotated by approximately 90 °, and is withdrawn from the bore of the central shift shaft under the force of the spring. In this position, however, the bolt preferably remains in a backdrop that limits the switching path of the central shift shaft. This backdrop is in turn molded into a pot that is placed on the central control shaft. The pot also has detents that interact with a corresponding ball catch so that the central shift shaft can be fixed in individual gears.

The transmission according to the invention can have two types of actuating elements. One type is the actuation by means of log trains. In this case, these building trains are connected with levers that allow axial displacement and rotation of the central shift shaft. A lever is clamped with an end piece between two ends of a metal strip that is folded around the central selector shaft. This sheet metal strip is fixed in this position by two plates pushed onto the central selector shaft from each side, which are in engagement with parts of the sheet metal strip. An end piece of the other lever can in turn be clamped between these two plates. Such a connection is easy to make and very functional. - 5 -

If, on the other hand, actuation via a shift rod is desired, this shift rod is articulated with a pipe piece in the context of the present invention. In the pipe piece there is in turn a ball head which is connected to the central switching shaft via a connecting element.

Although protection is sought for individual elements of the present invention, protection relates primarily to the combination of all of these elements. Above all, it should be mentioned that the essential actuation elements can be fixed on the tubular central selector shaft without difficulty. If welding is not possible, such as with a brass component on a steel bushing, this component can be flanged onto the central control shaft.

Above all, it should also be mentioned that essential components are neither made from solid material nor from cast material, but are simply punched components that are then bent accordingly. This also simplifies and reduces the cost of manufacture.

- 6 -

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

1 shows a cross section through a transmission according to the invention;

FIG. 2 shows a cross section through a section of the transmission according to FIG. 1, in particular from the area of a central shift shaft;

Figures 3a and 3b plan views of the central selector shaft from two directions;

Figures 4a and 4b sections of the transmission from the area of the coupling between a shift finger on the central shift shaft and a driver in two positions of use;

FIG. 5 shows an enlarged section of the transmission from the area of a device for fixing the central shift shaft;

Figures 6a to 6d different views of a pot to limit a switching path or a detent;

Figures 7a to 7c top views of individual parts and a synopsis of an actuating element for a central switching shaft.

According to FIG. 1, a transmission has a housing 1 in which a central shift shaft 2 is located. This central control shaft 2 is designed as a tube, a bolt 3 or 4 engaging in the central control shaft 2 at each end. Each bolt 3 or 4 is supported - 7 - an inner bearing 5 or 6 against an inner wall 7 of the central shift shaft 2.

Shift fingers 8 and 9 are located on the central shift shaft 2, the shift finger 9 being in engagement with a driver 10 for actuating a shift fork 11. The shift finger 8 is outside of an engagement in a driver.

The shift finger 9 can also be brought into engagement with a further driver 12, via which a further shift fork 13 can be moved on a shift rod 14.

The central shift shaft 2 is movable in the direction of its longitudinal axis A; it is also rotatable to a certain extent about its longitudinal axis A. Two options are indicated for these movements in the present exemplary embodiment. On the one hand, the movement can take place via a shift rod 15, which is inserted into a pipe piece 16 and secured there by means of a cross bolt 17. Compared to the shift rod 15, the tubular piece 16 rotates a spherical head 18 which is fixed to the central shift shaft 2 via a connection 19.

In a further possibility of actuating the central shift shaft 2, two building trains are provided, the entry into the transmission of which is identified by 20 and 21. In Figure 7c only end pieces 22 and 23 of levers can be seen, which are connected to the Baudenzug, the end piece 22 is held by two ends 24.1 and 24.2 of a sheet metal strip 25. This sheet metal strip 25 is shown in FIG. 7a after punching and before folding. It is preferably connected to the central shift shaft 2 via rivets 26. - 8th -

In the bent use position, plates 27 abut the sheet metal strips 25 from both sides, one plate being shown in FIG. 7b. The plate 27 has notches 28.1 and 28.2 which are plugged onto the ends 24.1 and 24.2 of the metal strip 25 in the folded state. Furthermore, the plate 27 has two slots 29.1 and 29.2 into which projections 30.1 and 30.2 of the metal strip 25 are inserted.

The two plates 27 hold the end piece 23 of the second building train between them.

To limit the switching path and for locking the central switching shaft 2, a pot 31 is placed, which is shown in more detail in Figures 6a to 6d. The pot 31 has a shaft 32 which, in the position of use, sits closely on the central switching shaft 2 and is riveted to the latter.

After the shaft 32, the pot opens, a gate 34 for limiting the switching path of the central switching shaft 2 and a detent 35 being formed in its wall 33. It can be seen in FIG. 2 that the detent 35 interacts with a ball catch 36 which is mounted fixed to the housing.

A pin 37 engages in the setting 34, which is at the same time a component of a device 38 for fixing the central shift shaft 2. This bolt 37 not only passes through the link 34, but can also engage in a bore 39 in the central control shaft 2 or in a disc 40, shown in FIG. 5, which is attached to the central control shaft 2. In this way, the central shift shaft 2 is fixed, which is necessary, for example, for various setting operations of the transmission.

The insertion of the bolt 37 into the bore 39 takes place against the pressure of a helical spring 41, which is - 9 -

supported on the one hand against a fixed nut 42 and on the other hand against a support ring 43. The bolt 37 is moved by means of a handle 44.

The bolt 37 also slides in a guide sleeve 45, which ends in the transmission in front of the backdrop 34 with an inclined surface 46. A cross bolt 47, which crosses the bolt 37, is supported against the inclined surface 46. If the handle 44 is rotated by approximately 90 °, the bolt 37 m slides into the bore 39, and the transverse bolt 47 slides into a notch 48 at the tip of the guide sleeve 45, so that the bolt 37 is held in this position.

It can be seen in FIG. 2 that the end pieces 22 and 23 are fixed to levers 49 and 50, these levers 49 and 50 being actuated by the above-mentioned hoist pulls.

According to Figures 3a and 3b, the central switching shaft 2 is designed as a tube. It has holes 51 and 52 for fixing the pot 31 and the sheet metal strip 25. Furthermore, the shift fingers 8 and 9 are welded onto it.

In the area of the shift fingers 8 and 9, the central shift shaft 2 should have recesses 53.1, 53.2 and 54.1, 54.2. These recesses have the following functions:

In Figure 4b it can be seen that the shift finger 9 m engages a receptacle 55 of the driver 10. The central shaft 10 is actuated by rotating the central shift shaft 2, i.e. the shift fork 11 is shifted via it along a shift rod 56 (see FIG. 1), since the shift rod 56 is arranged at approximately a right angle to the central shift shaft 2.

During this movement, a support 57 of the driver 10 slides into the recess 54.1 - 10 -

Recess 54.1 only permits displacement of driver 10 at all.

If the shift finger 9 is rotated in the opposite direction, a further support 58 can be accommodated in the recess 54.2.

Both supports 57 and 58 have a rounded sliding surface 59 and 60.

If the shift finger 9 is outside of the engagement in the receptacle 55, as shown in FIG. 4b, ie if another shift fork is actuated by this shift finger 9 or the other shift finger 8, ie a different gear is actuated, then the driver is in the position shown in Figure 4b, in which the supports 57 and 58 can not penetrate the corresponding recesses 54.1 and 54.2, but the sliding surfaces 59 and 60 sit on the central shift shaft 2. This means that in this position the sliding surfaces 59 and 60 maintain a distance from the longitudinal axis A of the central control shaft 2 which corresponds to the radius r of the central control shaft 2.