FR2749907A1 - Linear and rotary sensors of position of control shaft in motor vehicle gearbox - Google Patents

Abstract

The detector for a gearbox consists of a body (9) carrying two sensors (3,4) for producing a signal representing the position of the control shaft. The sensors are the image one of the other and that the body is in the form of a tube. This tube has inside it a operating sleeve (13) which drives in rotation an input element (8) of one of the sensors called the primary sensor (3), mounted coaxially with this sleeve. This operating sleeve (14) is so formed to drive in rotation a rotary piece (17-20) forming the input to the other sensor (4) which is placed perpendicular in relation to the primary sensor (3). It is coupled to the control shaft of the gearbox by an attachment (20).

Description

 The present invention relates to a device for detecting the linear angular position of the control shaft of a gearbox, in particular of a vehicle.

 As is known, the control shaft of a gearbox is mounted to slide longitudinally and to rotate about its longitudinal axis with respect to a part of the gearbox housing to occupy any one of several predetermined relative positions, each of which corresponds to the engagement of one of the stepped ratios of the gearbox.

 This gearbox has, in known manner, pinions and shift and selection means for changing the transmission ratio.

 The gear change is carried out using a gear shift lever connected by a transmission to the control shaft.

 The gearshift lever can be moved angularly and axially by means of a gearshift grid provided with engagement slots to usually define five forward positions, one position for reverse and a neutral line. , knowing that the passage, for example, from the first to the second speed is effected by means of the passage means and the level change, for example, from the second to the third speed is effected by means of the selection means, with a neutral line.

 As is known, the control shaft includes at least one control finger belonging to the passage and / or selection means.

 This finger is adapted to cooperate with sliders each associated with a synchronizer-dog clutch assembly.

 It is necessary to detect, in certain cases, the position of the control shaft, in particular to ensure, in a reliable manner, an automatic control of the clutch associated with the gearbox.

 Indeed, it is necessary for example to prohibit a vehicle start when the gear engaged is other than first gear or reverse gear.

 In general, this automatic control depends on the driving conditions of the vehicle and therefore on the gear engaged.

 Such a detection device is described in document FR-A-2 643 316.

 This device is not compact.

 We can then consider creating a detection device comprising a body forming a housing and carrying two sensors capable of producing signals representative of the position of the control shaft and intended in particular to be operated by the control circuit of a control mechanism. control of a clutch associated with the gearbox.

 In general, the detection device is a specific piece integrating the measurement of the two movements in a single case. The development of such a device is long and expensive.

 In addition, the risk of jamming must be avoided so that the device is reliable.

 It is therefore an object of the invention to create a compact detection device using inexpensive sensors.

 It is another object of the invention to minimize the risk of jamming of the constituent parts of the detection device.

 According to the invention, a detection device of the above-mentioned type is characterized in that the sensors are filed one from the other, in that the body has a generally tubular shape and internally receives a clean operating sleeve to rotate an input element of one of the sensors, said first sensor, mounted coaxially with respect to said sleeve, in that the operating sleeve is shaped to rotate a rotary part forming the element d input of the other sensor, called the second sensor, in that the second sensor extends perpendicularly to the first sensor, and in that the operating sleeve carries means for its coupling to the control shaft of the gearbox.

 Thanks to the invention, the detection device is compact and makes it possible to use standard sensors sold in millions of copies.

 These sensors are in the image of each other thanks to the sleeve and the rotating part.

 The risk of jamming is reduced because the number of parts required to drive the sensors is reduced.

 In addition, these parts are simple and economical.

 In one embodiment, the body is advantageously obtained by molding and laterally has an appendage for fixing the second sensor.

 The first sensor delimits with the body a blind cavity inside which moves in rotation and in translation the operating sleeve carrying at its free end coupling means for its coupling to the control shaft of the gearbox. speeds.

 Thus, thanks to the appendix and by providing the body at its rear end for example with a fixing flange, it is easy to install the casings of the sensors, advantageously identical, perpendicularly to one another.

 To reduce the radial size, the rotary part comprises a finger engaged in a groove made at the outer periphery of the operating sleeve.

 The finger is preferably cylindrical in shape, which reduces the risk of jamming, the finger coming into local contact with the sides of the throat.

 For simplification of the rotary part, the latter comprises an arm forming a link and carrying the finger. This arm is integral with a rod with an upper end in the form of a grooved tree.

 The arm is housed at angular movement in a recess made in the appendix of the body and closed by the second sensor.

 Thus the translational movement of the sleeve is transformed into rotation by the link which activates, via the rod with a grooved end, the second sensor.

 The rotational movement of the operating sleeve is taken up directly by the first sensor.

 For example, the input element of the first sensor consists of a splined shaft engaged in a grooved internal bore formed in said sleeve.

 It follows that the input or actuation elements of the sensors have a different shape.

 The detection device is reliable, compact and inexpensive. I1 thus comprises a reduced number of parts of simple and economical shape, namely two standard sensors, two sensor actuating elements, an operating sleeve and a body advantageously made of moldable plastic material with low coefficient of friction to facilitate the movements of the operating sleeve.

 Of course, the invention is also applicable in the case where the operation of the gearbox control shaft is carried out using actuators.

The following description illustrates the invention with reference to the accompanying drawings in which
- Figure 1 is an exploded perspective view of a detection device according to the invention
- Figure 2 is a view similar to Figure 1 in exploded perspective
- Figure 3 is a view along arrow 3 of Figure 2
- Figures 4 and 5 are partial views of the front end of the detection device for other embodiments.

 The detection device 1 shown in these figures is intended to detect the linear and angular position of the control shaft (not shown) of a gearbox, here mechanical, with pinions and stepped transmission ratios, for a motor vehicle.

 This device comprises, for this purpose, coupling means 2 for its coupling in rotation and in translation to said control shaft.

 As is known, a clutch forming a cutoff and starting member is interposed between the output shaft (the crankshaft) of the internal combustion engine of the vehicle and the input shaft of the gearbox.

 The detection device 1 is suitable for sending signals to a computer belonging to a control circuit of an automatic or semi-automatic clutch control mechanism, usually with a diaphragm, associated with the gearbox in the aforementioned manner.

 For example, the computer is capable of activating an electric motor which, via a mechanical transmission, acts on the piston of a hydraulic cylinder of a transmitter connected by a pipe to a hydraulic receiver cylinder whose piston moves in translation a clutch release bearing acting on the internal end of the diaphragm fingers which, when the clutch is engaged, acts on a reaction plate to tighten a friction disc, locked in rotation on the input shaft of the gearbox, between the pressure and reaction plates integral in rotation with the crankshaft of the vehicle engine. To do this, the pressure plate is linked in rotation - with axial mobility - to a cover, on the one hand integral with the reaction plate and, on the other hand, providing support to the diaphragm.

 Elastic assistance means act in parallel with respect to the electric motor, on one of the transmission members, while mechanical compensation means ensure controlled modulation of the action of the elastic assistance means.

 We can, for more explanations, refer for example to document FR-A-2 721 264.

 The clutch control mechanism further includes a broken type shift lever.

 To do this, the lever comprises a force detector interposed between a front section and a downstream section connected to a control linkage of the control shaft of the gearbox. The force sensor also sends a signal to the computer in order to activate the electric motor and to move the clutch release bearing in order to tilt the diaphragm to cancel its action on the pressure plate, release the friction disc and disengage the clutch. .

 The activation of the electric motor depends on the gear engaged and this is the reason why it is important to know the position of the control shaft.

 It is therefore important to detect the linear angular position of said shaft to, for example, avoid starting the vehicle when a gear, other than the first or reverse gear, is engaged.

 To do this, the aforementioned detection device 1 carries a first sensor 3 and a second sensor 4.

 The first sensor 3 is intended to detect the linear position of the control shaft, while the second sensor 4 is intended to identify the angular position of the control shaft.

 According to a characteristic of the invention, the sensors 3,4 are in the image of one another, which makes it possible to reduce the number of reference parts that the detection device 1 comprises.

 These sensors 3,4 are intended to send signals to the computer while being connected to the latter by connecting lines, here electrical wires.

 For this reason, the sensors 3,4 each have a connector 5 here with terminals 6. The connectors 5 are each suitable for being connected to a complementary connector constituting the terminal part of the electrical wires connected to the computer.

 Here, the connectors 5 are integral with the housing 7 that each sensor 3,4 has.

 Each housing 7 is closed by a cover 12 for forming the casing 7, 12 inside which the sensor parts are housed.

 The sensors 5 constitute the output elements of the sensors 3,4 each comprising an input element 8,20 forming an actuating element of the sensor.

 The sensors ", 4 are mounted perpendicularly to each other by being attached to a body 9 which comprises the detection device 1 which is thus very compact according to a characteristic of the invention.

 The body 9 has a simple shape. Here it is generally tubular in shape. It has an appendage 10 laterally with a recess 11.

 Appendix 10 presents holes not referenced for fixing members, such as screws or bolts, used to fix the casing 7, 12 of the second sensor 4 to the body 9, and this perpendicular to the first sensor 3.

 For this purpose the body 9 has at its rear end a flange 13 provided with holes not referenced serving to fix the casing 7, 12 of the first sensor 3 to the body 9 by means of fixing members such as screws or bolts. .

 The body 9 is made of moldable material, so that the flange 13 and the appendix 10 adapt to the shape of the casings 7, 12 of the sensors 3, 4.

 This body 9, forming a support for the sensors 3, 4 also serves for fixing the detection device 1 to the casing of the gearbox.

 Its tubular shape makes it possible to house within it an operating sleeve 14, the external periphery of which is in internal contact with the internal periphery of the body 9. This body 9 therefore forms a guide member for the sleeve 14 and this is the reason for which it is advantageously made of plastic, advantageously with a low coefficient of friction.

 The body 9 defines with the first sensor 3 a blind cavity inside which slides and rotates the sleeve 14 as described below.

 The sleeve 14 has, here in one piece, a front end 15 projecting axially relative to the body 9. This front end is in the form of a rod carrying at its free end a transverse finger carrying a ball joint belonging to the coupling means 2 from device 1 to the gearbox control shaft. The ball 2 is intended to be mounted in a seat coupled to the control shaft.

 Internally, the sleeve 14 is provided with a blind hole or longitudinal bore 21 open at its rear end opposite the first sensor 3, the input element 8 of which is mounted coaxially with respect to the body 9 and to the sleeve 14.

 The first sensor 3 forms a shutter for the rear end of the body 9.

 The sleeve 9 has, at its outer periphery, a groove 16.

 In the groove 16 is mounted a cylindrical finger 17.

 The finger 17 is carried cantilevered by an arm 18 forming a link, integral with a rod 19, here of vertical orientation, mounted with articulation at its two ends respectively in the recess 11 and in the second sensor 4 closing in the end the recess 11. The rod 19 extends perpendicularly to the arm 18 on either side of the latter.

Its lower end is rotatably mounted in a hole 30, here blind, of the recess 11 for its rotary mounting, while its upper end 20 forms a portion of splined shaft and the input and actuation element of the second sensor 4 here rotatingly carrying the shaft 20.

 The finger 17 extends vertically over a small height and perpendicular to the arm 18 and parallel to the rod 19.

 Here the finger 17, the arm 18 and the rod 19,20 are in one piece and belong to a rotary part for transforming translation movement into rotation. This part is advantageously made of moldable synthetic material. The rod 18 generally has a triangular shape with rounded angles. The rod 19 is located near the base of the triangle and the finger 17 near the top. The recess 11 is in the form of an annular sector to allow the housing and the angular movement of the arm 18 in the recess 11.

 As will be understood, the finger 17 being mounted in the groove 16, any movement in translation of the maneuvering sleeve 14 causes rotation of the shaft 20 forming the input and actuation element of the sensor 4 .

 The rotary part 17 to 20 and the groove 16 belong to means for transforming a linear movement into a rotary movement. These means will be referred to below as second means.

 It will be appreciated the simple shape of the rotary part 17 to 20 constituting one of the characteristic elements of the invention.

 The recess 11 is used for housing this rotary part 17 to 20 which carries the cantilever finger 17 penetrating into the groove 16 formed at the external periphery of the sleeve 14. The finger 17 forms the crank pin of the link 18.

 The rotary part 17 to 20 is carried by the appendix 10 while being mounted so rotary on the body 9.

 Thus, as described below, the translational movement of the sleeve 14 inside the body 9 is transformed into rotation by the link 18 which actuates, by the shaft 20 and the second sensor 4.

 The rotation movement of the sleeve 14 is taken up directly by the input element 8 of the sensor 3.

 This input element 8 extends, according to a characteristic of the invention, coaxially with the sleeve 14.

More specifically, the internal bore 21, of axial orientation, of the sleeve 14 is provided with axial grooves 22 for receiving, in a complementary manner, splines belonging to a splined shaft 8 forming the input and actuation element of the first sensor 3. It is thus formed of meshing means, here without circumferential play, between the shaft 8 and the sleeve 14.

 These meshing means form rotational connection means, called first means, intervening between the sleeve 14 and the input element 8 of the first sensor 3.

These means allow axial displacement of the sleeve 14 relative to the shaft 8.

 As will be understood, any linear movement of the control shaft causes, via the coupling means 2, a rotation of the sleeve in the body 9 and an actuation of the first sensor 3, the second sensor 4 is not actuated because the cylindrical finger 17 moves inside the annular groove 16, with the sides of which it is locally in contact due to its cylindrical shape.

 Any angular displacement of the control shaft causes, via the coupling means 2, a translation of the sleeve 14 inside the body 9. During this translation, the first sensor 3 is not actuated because the sleeve 14 slides axially with respect to the shaft 8.

 On the other hand, the movement of the groove 16 causes the finger 17 to move without risk of jamming and a rotation of the rod 19 and of the shaft 20. The sensor 4 is then actuated by its actuating or input element 17 at 20.

 Here the sensors 3, 4 are advantageously identical, apart from the input elements 8 and 19 to 20, and are economical sensors which are commercially available in large series.

 They consist here of rotary potentiometers, so that the shafts 8,20 cause sliders mounted in the housings 7,12 of the sensors 3,4.

 The shafts 8,20 pass through the covers lé and are integral in rotation with the rotary sliders of the potentiometers whose resistance is mounted inside the casing 7,12.

 The cursor moves to the resistor across which a reference voltage is applied.

 As a variant, the sensors are of the optical type and the cursors are replaced by read heads provided with a transmitting diode and a receiving diode, the box 7 internally carrying a track with marks. The rotation of the read head allows a count of the number of marks giving information on the movement of the head.

 As a variant, the rotary cursor is adapted to cooperate with electrical tracks carried by the housing 7. During its rotation, the cursor establishes electrical circuits determined according to the applications.

 Alternatively, the sensors are of the magnetic type.

 In all cases, the detection device is economical because, thanks to its body 9, it can be fitted with inexpensive commercial sensors.

 In addition, the sensors 3,4 are generally identical and are sensors of the rotary type. The groove 16 is easy to produce as well as the movement transformation part 17 to 20.

 The finger 17 is placed at one of the rounded vertices of the rod 18 of generally triangular shape. The cylindrical shape of the finger 17 makes it possible to have punctual contact with the sides of the groove 16.

 All this makes it possible to avoid jamming phenomena. The detection device is therefore reliable and robust. The trees 8.20 are easy to produce and are economical, like the sleeve 14.

 Of course, a play may exist between the finger 17 and the sides of the groove 16, as well as between the grooves of the shaft 18 and the internal grooves 22 of the sleeve 14. This makes it possible to prevent vibrations of the shaft the sliders to the detriment of the life of the sensors 3,4. In this case, the computer takes these clearances into account to determine the displacements of the control shaft via the sensors.

 Of course, the gearbox instead of being controlled manually using a mechanical transmission and the gearshift lever, possibly broken, can be controlled using an actuator. In this case it is also useful to know the gear ratio engaged.

 The coupling means 2 can have another shape.

 For example, in Figure 5, the rod 1 (may have a cutout at its free end and the control shaft 40 a complementary cutout.

 A finger 41 carried by one of the rod-control shaft elements is received in a hole carried by the other of said elements.

 The body 9 can be fixed to the gearbox casing by a bayonet-type assembly 50 (FIG. 6) or by means of a fixing flange carried for example by the front end of the body 9 ( figure 5).

 In FIG. 6, the body 9 carries sections of ramps separated two by two by passages for a lug belonging to a fixed part of the vehicle and suitable for entering a groove delimited by a flange coming from the body 9.

Claims (12)

 1) Detection device for detecting the angular and linear position of a control shaft of a gearbox, in particular of a motor vehicle, comprising a body (9) carrying two sensors (3,4) capable of producing representative signals of the position of the control shaft and intended in particular to be operated by a control circuit for a control mechanism of a clutch associated with the gearbox, characterized in that the sensors (3,4) are at the image of each other, in that the body (9) has a generally tubular shape and internally receives an operating sleeve (13) suitable for rotating an input element (8) of a sensors (3,4), said first sensor (3), mounted coaxially with respect to said sleeve, in that the operating sleeve (14) is shaped to rotate a rotating part (17 to 20) forming the input element of the other sensor (4), said second sensor, in that the second sensor (4) extends perpendicularly to the first sensor (3), and in that the operating sleeve (14) carries means (2) for its coupling to the control shaft of the gearbox.  2) Detection device according to claim 1, characterized in that the rotary part (17 to 20) door overhang a finger (17) penetrating into a groove (16) formed at the outer periphery of the operating sleeve.  3) Detection device according to claim 2, characterized in that the finger (17) is of cylindrical shape for local contact with the sides of the groove (16).  4) Detection device according to claim 2 or 3, characterized in that the finger (17) is secured to an arm (18), forming a link, secured to a rod (19) by means of which the arm (18) is rotatably mounted on the body (9).  5) Detection device according to claim 4, characterized in that the rod (19) is provided at its other end with a grooved portion (20) forming an actuating and input element of the second sensor (4).  6) Detection device according to any one of claims 1 to 5, characterized in that the second sensor (4) is mounted on an appendage that has the body laterally (9).  7) Detection device according to claims 6 and 4 taken together, characterized in that the appendix (10) has a recess (11) in which is housed at angular movement the arm (18).  8) Detection device according to claim 7, characterized in that the rod (19) is rotatably mounted in a hole (30) of the recess).  9) Detection device according to any one of claims 1 to 8, characterized in that the operating sleeve (14) has an internal bore (21) provided with grooves for receiving grooves belonging to a splined shaft element (8) forming the input and actuation element of the first sensor (3).  10) Detection device according to claim 9, characterized in that the internal bore (21) of the operating sleeve (14) is blind and in that said sleeve (14) bears in one piece at its free end of the means (2) for its coupling to the control shaft of the gearbox.  11) Detection device according to claim 2, characterized in that a clearance exists between the finger (17) and the sides of the groove (16).  12) Detection device according to claim 9 or 10, characterized in that a clearance exists between the grooves of the splined shaft (8) and the grooves (22) of the operating sleeve (14).