Device for sensing the linear position of a transmission member in the form of a cable attached to a lever of a motor vehicle gearbox

Abstract

A device for detecting the position of a lever includes a member being connected on at least one of its ends to a cable end piece that is fitted sliding into a fixed sheath end piece. The device comprises a magnet fitted inside a pipe that constitutes the cable end piece and a Hall Effect Sensor positioned on one part of the sheath end piece in order to detect the movement between the cable end piece and the sheath end piece, which corresponds to a movement of the lever.

Claims

1. A device for sensing the linear position of a transmission member, comprising: a cable attached to a control lever of a motor vehicle gearbox to detect a position of the control lever, wherein the transmission member is connected on at least one of its ends to an end piece of the cable, the end piece of the cable fitted slidably within a fixed sheath, wherein the end piece of the cable comprises a pipe and a magnet fitted inside the pipe, wherein the magnet is a permanent magnet and a magnetization direction of the magnet varies linearly or sinusoidally depending on the direction of the movement between the end piece of the cable and the fixed sheath, and wherein a Hall Effect Sensor is positioned on the fixed sheath to detect movement between the end piece of the cable and the fixed sheath, the movement corresponding to a change in position of the control lever.

2. The device according to claim 1, wherein the transmission member is fitted between the control lever and the gearbox, for selecting a gear of the gearbox.

3. The device according to claim 1, wherein the magnet is fitted inside the end piece of the cable at a position located next to the control lever.

4. The device according to claim 1, wherein the magnet is fitted inside the end piece of the cable at a position located next to the gearbox.

5. The device according to claim 1, wherein the magnet is a product of having been inserted into the pipe.

6. The device according to claim 1, wherein the magnet is a product of having been molded from a casting inside the pipe.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention is explained in more detail hereinafter, with the help of the figures given in the annex, in which:

(2) FIGS. 1 and 2 are schematic, sectional views showing the principle of the linear measurement of the cable end piece with respect to the sheath end piece.

DETAILED DESCRIPTION

(3) Bear in mind that the lever (not shown) for controlling gear shifting and selection is assembled with angular movement capacity in a support housing. The foot of the lever is connected to the control cables, which are themselves connected to the corresponding members of the gearbox. One of these cables corresponds to the gear selection whereas the other cable corresponds to gear shifting. Always in a known manner, these cables (C) are assembled sliding into a sheath (G) and are interdependent with a cable end piece (1) that is assembled sliding into a sheath end piece (2). The sheath (G) has a coupling sleeve (3) with, for example, a part of the lever support. The end of the cable end piece (1) is also fixed to a coupling member (4) with a part of the gearbox. These different solutions are not described in detail as they are known perfectly by the person skilled in the art.

(4) As indicated, the purpose is to detect the position of a gearbox control, i.e., the position of the lever, by measuring the linear position of the cable end piece (1) with respect to the sheath end piece (2). For this purpose, according to a basic characteristic of the invention, the device for sensing this liner position comprises a magnet (5) fitted inside the cable end piece (1) in the form of a pipe. The bore of the pipe (1) is therefore used for setting the magnet (5) in place. The magnet (5) may either simply be inserted into the pipe, or molded from a casting inside the pipe. Note that this magnet (5) may preferably be a permanent magnet, the direction of which varies linearly or sinusoidally depending on the direction of movement of the end piece (1). This characteristic of the magnet is shown, for example, in the information given in patent EP 1989505.

(5) In combination with the magnet (5), a Hall Effect Sensor (6) is positioned on a part of the sheath end piece (2) in order to detect, as explained before, the movement between the cable end piece (1) and the sheath end piece (2) corresponding to a movement of the lever.

(6) Preferably, the magnet (5) is fitted in the cable end piece (1) corresponding to the gear selection cable.

(7) Note that the magnet (5) may be fitted inside the cable end piece that is located either next to the lever or next to the gearbox.

(8) The advantages are quite evident from the description.

(9) The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.