Shift device having rotational free travel for the shift shaft, and motor vehicle transmission having such shift device

Abstract

A shift device for a motor vehicle transmission, in particular for a motor vehicle automatic transmission, includes a shift shaft operatively connected to the transmission and a shift lever for actuating the shift shaft, wherein the shift shaft and the shift lever are connected to one another by way of a spline connection. The spline connection is formed with rotational play, permitting a restricted rotational free travel of the shift shaft when the shift lever is stationary. A motor vehicle transmission having a shift device of this type is also disclosed.

Claims

1. A shift device for a transmission of a motor vehicle, comprising: a shift shaft operatively connected to the transmission, a shift lever for actuating the shift shaft, wherein the shift lever is connected to the shift shaft by a first spline connection having rotational play, thereby enabling limited rotational free travel of the shift shaft when the shift lever is in a fixed position, a shift sensor connected to the shift shaft in a rotationally fixed arrangement by way of a second spline connection, wherein the second spline connection comprises an inner spline formed on the shift sensor and having a circular cylindrical contour and a plurality of radially outwardly directed and mutually circumferentially spaced notches, and an outer spline formed on the shift shaft and having a circular cylindrical contour and a plurality of radially outwardly directed and mutually circumferentially spaced teeth, and a double tooth formed on the outer spline and a double notch formed on the inner spline, with the double tooth and the double notch defining a precise angular alignment between the shift sensor and the shift shaft.

2. The shift device of claim 1, wherein the transmission is an automatic transmission of a motor vehicle.

3. The shift device of claim 1, wherein the limited rotational free travel has an angle of rotation of between 40 and 60.

4. The shift device of claim 1, wherein the first spline connection comprises an inner spline formed on the shift lever and having a circular cylindrical contour and a plurality of radially inwardly directed, mutually circumferentially spaced teeth, and an outer spline formed on the shift shaft and having a plurality of radially outwardly directed and mutually circumferentially spaced teeth.

5. The shift device of claim 4, wherein the teeth of the outer spline and the teeth of the inner spline are spaced apart in the circumferential direction by uniform gaps.

6. The shift device of claim 4, wherein the outer spline and the inner spline have each between 4 and 8 teeth.

7. The shift device of claim 6, wherein the outer spline and the inner spline have each 6 teeth.

8. A transmission of a motor vehicle, comprising a shift device with a shift shaft operatively connected to the transmission, and a shift lever for actuating the shift shaft, wherein the shift lever is connected to the shift shaft by a first spline connection having rotational play, thereby enabling limited rotational free travel of the shift shaft when the shift lever is in a fixed position, a shift sensor connected to the shift shaft in a rotationally fixed arrangement by way of a second spline connection, wherein the second spline connection comprises an inner spline formed on the shift sensor and having a circular cylindrical contour and a plurality of radially outwardly directed and mutually circumferentially spaced notches, and an outer spline formed on the shift shaft and having a circular cylindrical contour and a plurality of radially outwardly directed and mutually circumferentially spaced teeth, and a double tooth formed on the outer spline and a double notch formed on the inner spline, with the double tooth and the double notch defining a precise angular alignment between the shift sensor and the shift shaft.

9. The transmission of claim 8, wherein the transmission is an automatic transmission of a motor vehicle.

10. The transmission of claim 8, wherein the transmission is a shift-by-wire transmission.

11. The transmission of claim 8, wherein the first spline connection comprises an inner spline formed on the shift lever and having a circular cylindrical contour and a plurality of radially inwardly directed, mutually circumferentially spaced teeth, and an outer spline formed on the shift shaft and having a plurality of radially outwardly directed and mutually circumferentially spaced teeth.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) It is shown schematically and by way of example in:

(2) FIG. 1 a shift device according to the invention in an exploded perspective view;

(3) FIG. 2 the shift lever associated with the shift device of FIG. 1 in an axial plan view;

(4) FIG. 3 the shift sensor associated with the shift device of FIG. 1 in an axial plan view;

(5) FIG. 4 the front axial end of the shift shaft associated with the shift device of FIG. 1 in a perspective view; and

(6) FIG. 5 the shift lever of FIG. 2 connected to the shift shaft of FIG. 4 via a spline connection in an axial plan view.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(7) FIG. 1 shows a shift device according to the invention generally designated with 100. The shift device 100 includes a shift shaft 110, a shift lever 120 and a shift sensor or shift position sensor 130, respectively. The exemplary one-piece components 110, 120 and 130 are for illustrative purposes shown separately by pulling them apart along the common rotation or swivel axis L.

(8) The shift lever 120 and the shift sensor 130 can be connected to the shift shaft 110, for which purpose the shift shaft 110 is pushed in the direction of the axis L onto the front axial end 11 of the shift shaft 110 (which is in particular the axial end facing away from the transmission of the motor vehicle). The connection is established by way of a spline connection, wherein the front axial end 111 of the shift shaft 110 is formed with an outer spline or an outer spline section 112, as will be explained in more detail below. Correspondingly, the shift lever 120 is formed with an inner spline 122 and the shift sensor 130 is formed with an inner spline 132. The inner splines 122 and 132 of the shift lever 120 and the shift sensor 130 are constructed differently, as will be explained in more detail below with reference to FIGS. 2 and 3.

(9) FIG. 2 shows the shift lever 120 in a plan view along the axis L. The shift lever 120 has a circular cylindrical bore 121. The bore 121 is formed with an inner spline or an inner spline section 122, respectively. The inner spline 122 has a plurality of teeth 123, which are radially inwardly directed starting from the inner wall of the bore or the bore contour and have a mutual spacing in the circumferential direction. In the illustrated exemplary embodiment, six teeth 123 are provided which are arranged with a uniform distribution in circumferential direction on the inner wall of the bore.

(10) FIG. 3 shows the shift sensor 130 in a plan view along the axis L. The shift sensor 130 has a circular cylindrical bore 131. The bore 131 is also formed with an inner spline or an inner spline section 132. Unlike the inner spline 122 of the shift lever 120, the inner spline 132 of the shift sensor 130 has several notches 133 which are directed radially outwardly, starting from the inner wall of the bore or the bore contour and are circumferentially spaced from one another. In the illustrated embodiment, six grooves 133 are provided, which are arranged on the inner wall of the bore with a uniform distribution in the circumferential direction. Furthermore, a double notch 133a/133b is provided for arranging and/or connecting the shift sensor 130 on the shift shaft 110 at a precise angle.

(11) FIG. 4 shows the front axial end 111 of the shift shaft 110. The shift shaft 110 is formed in this end portion with an outer spline or an outer spline section 112. The outer spline 112 has a plurality of teeth 113, which are directed radially outwardly, starting from a circular cylindrical surface, and are spaced relative to each other in the circumferential direction. In the illustrated exemplary embodiment, six teeth 113 are provided, which are uniformly distributed in the circumferential direction on the outer surface of the axial end portion 111. Furthermore, a double tooth 113a/113b is provided for arranging and/or connecting the shift sensor 130 on the shift shaft 110 at a precise angle.

(12) The shift sensor 130 is connected with the shift shaft 110 in a rotationally fixed arrangement due to the positive engagement of the teeth 113 associated with the outer spline 112 of the shift shaft 110 with the notches 133 associated with the inner spline 132 of the shift sensor 130, thereby forming a play-free spline connection. The engagement between the double tooth 113a/113b on the shift shaft 113a/113b in the double notch 133a/133b on the shift sensor 130 results in an angularly precise alignment of the shift sensor 130 on the shift shaft 110.

(13) The shift lever 120 is also connected with the shift shaft 110 by a spline connection; however, this spline connection has rotational play, thereby allowing a limited rotational free travel of the shift shaft 110 relative to the shift lever 120 and/or vice versa. This will be explained below with reference to FIG. 5.

(14) FIG. 5 shows in an axial top view (view along the axis L) the shift lever 120 connected with the shift shaft 110 by way of a spline connection. The spline connection is realized by the positive engagement of the outer spline 112 disposed on the shift shaft 110 and the existing inner spline 122 disposed on the shift lever 120, wherein the teeth 113 and 123 overlap in the radial direction. The tooth heights of the respective teeth 113 and 123 are matched.

(15) As already explained above, both the radially outwardly directed teeth 113 of the shift shaft 110 and the radially inwardly directed teeth 123 on the shift lever 120 have a mutual spacing in the circumferential direction. The gaps between the teeth formed in this way allow limited rotational free travel between the shift shaft 110 and the shift lever 120.

(16) In the diagram shown in FIG. 5, the teeth 113 of the shift shaft 110 are in physical contact with the teeth 123 of the shift lever 120. This illustrated condition can be caused, for example, by applying a spring force to the shift shaft 110. On the one hand, torques can then be transmitted between the shift shaft 110 and the shift lever 120 in one direction. On the other hand, the shift shaft 110 can rotate counterclockwise about the rotation angle or pivot angle a from the illustrated position when the shift lever 120 is stationary, until the teeth 113 the shift shaft 110 contact the adjacent teeth 123 of the shift lever 120 in the direction of rotation of (wherein all the teeth touch simultaneously or at the same time in direct contact). Torques can then be transmitted between the shift shaft 110 and the shift lever 120 in the respective other direction. In a similar way, the shift shaft 110 can return to the illustrated position when the shift lever 120 is stationary.

(17) The spline connection existing between the shift shaft 110 and the shift lever 120 has thus both an entrainment function as well as a restricted or limited free travel function that allows rotational free travel for the shift shaft 110 within the rotation angle a when the shift lever 120 is stationary. (Similarly, the rotational free travel may of course also be used for pivoting the shift lever 120 when the shift shaft 110 is stationary.) The rotation angle a can be structurally specified by the number circumferentially spaced teeth 113 or 123 and/or by the tooth width. The angle of rotation a is dimensioned so as to be adequate for the aforementioned operating conditions (where a relative rotational movement between the shift shaft 110 and the shift lever 120, and in particular a rotation of the shift shaft 110, is required when the shift lever 120 is stationary). In the illustrated example, the rotational angle a is approximately 50. The teeth 113 and 123 have narrow dimensions along the circumference.

(18) Accordingly, both a rotationally fixed connection with the shift sensor 130 and a connection with the shift lever 120 having rotational free travel can be realized with one and the same outer spline 112 on the shift shaft 110, without the need for additional components (e.g. keys, pins, overrunning clutches, etc.). The external spline section 112 on the shift shaft 110 is formed with a corresponding axial length.