FR3075300A1 - ARRANGEMENT FOR DETECTING ANGULAR DISPLACEMENTS OF AN INTERNAL ELEMENT OF A MOTOR VEHICLE GEARBOX - Google Patents

Abstract

 The invention provides an arrangement for the detection, in a gearbox, of an internal element (10, 20) which is mounted movable, relative to the casing (13) of the gearbox, around an axis ( A) pivoting between at least two distinct angular positions, and which comprises an angular position sensor (26) carried by the casing (13), and a target (24) which is linked in angular displacement to said movable element (10, 20 ), characterized in that the target (24) comprises a stepped cam profile whose profile varies angularly, and in that the sensor (26) comprises an actuator (40) which is mounted movable radially relative to the housing (13) and of which a radially internal detection end (42) cooperates with the cam profile to detect said at least two distinct angular positions of the internal element (10, 20) each of which is associated with a stage of the stepped cam profile.

Description

Arrangement for detecting the angular displacements of an internal element of a motor vehicle gearbox

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an arrangement for the detection, in a motor vehicle gearbox, of an internal element such as a key for controlling the selection of a gear line, which is mounted so as to pivot in relation to a gearbox housing element, around an axis.

TECHNICAL BACKGROUND OF THE INVENTION

In a mechanical gearbox, gear changes are caused by axial movements of different components, and in particular pinions along parallel shafts, these axial movements of passage or engagement being preceded by a selection of a line of shifting reports.

This selection is carried out by means of a key, also called an interlocking key, which is rotatably mounted relative to the casing or housing of the gearbox about an axis relative to which it is likely to occupy. at least two distinct angular positions, and for example three adjacent angular positions.

When gear changes are carried out by means of a control system comprising controlled actuators, it is necessary to know precisely, reliably and repeatedly the angular position of the interlock key and to detect the changes of angular positions.

By way of nonlimiting example, the two speed or gear lines are angularly spaced by 15 degrees of angle.

Within this range, it is for example desirable to distinguish three consecutive angular ranges among which:

a) a first range between 0 and 5 degrees corresponding to the selection of the first gear shift line and in which the control system allows gear shifts;

b) a second intermediate range between 5 and 10 degrees in which the control system prohibits any gear change; and

c) a third following range between 10 and 15 degrees corresponding to the selection of the second gear shift line and in which the control system allows gear shifts.

In order to detect angular positions (as well as adjacent axial positions), it has already been proposed to use sophisticated devices using a magnetic target carried by a target holder integral with the component whose movements are to be detected and distinguished different positions, and using an associated fixed sensor, for example of the Hall effect type, carried by the gearbox casing, and which is for example arranged outside the casing.

Such an arrangement is for example described and represented in the document FR-A1 -3,044,065.

However, in the case of the detection of angular positions, the precision of such a magnetic device is between plus or minus 2 degrees of angle.

For the aforementioned detection of three ranges of approximately 5 degrees, such a level of precision is insufficient and results in refusals to shift gears when the control system wishes to cause actuations of gear shifts in angular zones located nearby. positions at 5 or 10 degrees of angle.

In the operation which has just been described, it is not so much the precision of the angular position which is essential, but rather the detection of the three consecutive ranges.

The invention aims to propose a solution which makes it possible to obtain this information in a precise, reliable and repetitive manner.

BRIEF SUMMARY OF THE INVENTION

The invention provides an arrangement for the detection, in a motor vehicle gearbox, of an internal element which is mounted movable, relative to the gearbox casing, around a pivot axis (A) between at least two distinct angular positions, and which comprises:

- an angular position sensor carried by the casing; and

a target which is linked in angular displacement to said mobile element, characterized in that:

- The target comprises a stepped cam profile whose profile varies angularly;

- And the sensor comprises an actuator which is mounted to move radially relative to the casing and one detection end of which cooperates with the cam profile to detect said at least two distinct angular positions of the internal element, each of which is associated with a stage of the cam profile.

According to other characteristics of the arrangement:

- the actuator is elastically biased in contact with the cam profile;

- each stage of the cam profile is delimited radially by a portion of the convex active surface in an arc of cylinder of axial orientation;

- Each stage of the cam profile is delimited radially by a portion of planar active surface of axial orientation parallel to the pivot axis;

- two consecutive active surface portions are connected together by a surface potion forming a ramp.

BRIEF DESCRIPTION OF THE FIGURES

Other characteristics and advantages of the invention will appear during the reading of the detailed description which will follow for the understanding of which reference will be made to the appended drawings in which:

- Figure 1 is a perspective view, with cutaway, which illustrates an internal control device of a gearbox which incorporates a detection arrangement according to the invention;

- Figure 2 is a detail view on a larger scale of the interlocking key of the control device of Figure 1;

- Figure 3 is a detail view on a larger scale and with partial cutaway which illustrates the angular position sensor, carried by the gearbox housing, belonging to the detection arrangement according to the invention; and

- Figures 4A to 4C are three axial end views which illustrates three angular positions of the interlocking key and the two main components of the detection arrangement according to the invention.

DETAILED DESCRIPTION OF THE FIGURES

In the following description, elements having an identical structure or analogous functions will be designated by the same references.

In the following description, longitudinal, vertical and transverse orientations indicated by the trihedron L, V, T in the figures will be adopted without limitation. A horizontal plane is also defined which extends longitudinally and transversely.

In Figure 1, there is shown an internal control arrangement belonging to a gearbox which, in known manner, essentially comprises a control member 10 which is rotatably mounted, or pivotally, in both directions around the axis A , a shaft 12, in order to occupy several angular positions.

The shaft A is mounted in opposite portions 13 of the gearbox housing.

The first angular position, called the first selection position, which is illustrated in particular in FIGS. 1 and 4A, is determined by a lug 14 of radial orientation belonging to the control member 10 which cooperates with fixed elements of angular stop belonging by example at the gearbox housing.

The control member 10 is returned elastically to this first position by an elastic return means 16 which is here produced in the form of a wire spring when the control member 10 is rotated in the direction S indicated in Figures 4B and 4C.

For its rotational drive in the direction S, against the return force applied to it by the spring 16, the control member 10 comprises a radial actuating tab not shown in detail on which acts a controlled actuator which is for example an electromagnetic cylinder.

When the actuator is controlled, it causes rotation, in the S direction, of the control member 10 towards its intermediate angular position illustrated in FIG. 4B, then towards its second angular selection position illustrated in FIG. 4C.

When the control and the power supply to the electromagnetic actuator are interrupted, the control member 10 is returned elastically under load, by the return spring 16, to its first angular position.

To allow the passage of different ratios, in one or the other of the two selection lines previously selected, two radial passage arms 18-1 and 18-2 are provided which rotate in both directions and move axially with the control member 10. In the first selection position, it is the first radial passage arm 18-1 which is received in a not shown dog clutch connected, in known manner, to a first line of pinions of the gearbox speeds.

The second passage arm 18-2 is released from a second associated dog clutch, not shown, itself connected, in known manner, to a second line of pinions of the gearbox.

When, under the action of the electromagnetic actuator, the control member 10 has angularly pivoted from its first angular selection position to its second angular selection position, the first passage arm 18-1 is released circumferentially from the first dog, while, in turn, the second passage arm 18-2 is engaged in the second dog.

Finally, the arrangement comprises a component called an interlocking key which is mounted to rotate with the control member 10 and which comprises two unrepresented locking blocks, each of which cooperates alternately with its associated dog clutch to block it when the line of corresponding selection is not selected.

The interlocking key comprises a cylindrical annular bell-shaped portion 20 of axial orientation which is delimited by a convex cylindrical outer wall 22 which carries a cam 24 formed in relief which belongs to the detection arrangement according to the invention and which constitutes a detection target with which cooperates a sensor 26 for detecting the angular positions of the interlocking key and of the control member 10 of which it is integral in rotation about the axis A.

The cam 24 is here delimited by two parallel radial sides 28 and by an upper cam profile P comprising three consecutive active surface portions 30, 32 and 34 each of which is in the general shape of a flat of axial orientation.

Each active surface portion 30, 32 and 34 can also be slightly convex in the shape of an axially oriented cylinder arc.

The two active surface portions 30 and 32 are interconnected by a first connecting surface portion 36 forming a ramp, of axial orientation, while the two active surface portions 32 and 34 are interconnected by a second portion connecting surface 38 forming a ramp, of axial orientation.

Thus, the first active surface portion 30 extends along an average radius R1, the second active surface portion 32 extends along an average radius R2, and the third active surface portion 34 extends along an average radius R3 (See Figure 4C).

The angular position sensor 26 can be of any type capable of providing a signal representative of the radial position of its actuator 40 in the form of a radial actuating finger which is capable of moving radially in both directions.

The radially internal free end 42 of the actuator 40 is of convex rounded profile and it is able to cooperate with the cam profile P of the cam 24.

To this end, the actuator is permanently elastically urged into contact support by its free end 42 against the cam profile P of the cam 24.

Thus, the actuator constitutes a cam follower element associated with the cam profile P of the cam 24.

Depending on the angular position of the cam 24 around the axis A, the actuator is able to cooperate with one of the surface portions 5, 30, 36, 32, 38 or 34.

Claims (5)

1. Arrangement for the detection, in a gearbox (13) of a motor vehicle, of an internal element (10, 20) which is mounted movable, relative to the gearbox casing, about an axis ( A) pivoting between at least two distinct angular positions, and which comprises: - an angular position sensor (26) carried by the casing (13); and - a target (24) which is linked in angular displacement to said mobile element (10, 20), characterized in that: - The target (24) comprises a stepped cam profile (P) whose profile varies angularly; - And the sensor (26) comprises an actuator (40) which is mounted to move radially relative to the casing (13) and one detection end (42) of which cooperates with the cam profile (P) to detect said at least two positions angular distinct from the internal element (10, 20) each of which is associated with a stage (30, 32, 34) of the cam profile (P). 2. Arrangement according to claim 1, characterized in that the actuator (40) is resiliently biased in contact with the cam profile (P). 3. Arrangement according to claim 1, characterized in that each stage of the cam profile (P) is delimited radially by a portion of active convex surface (30, 32, 34) in an arc of cylinder of axial orientation. 4. Arrangement according to claim 1, characterized in that each stage of the cam profile (P) is delimited radially by a portion of planar active surface (30, 32, 34) of axial orientation parallel to the pivot axis ( AT). 5. Arrangement according to claim 1, characterized in that two consecutive active surface portions (30-32, 32-34) are connected together by a surface potion forming a ramp (36, 38).