DEVICE FOR THE SEQUENTIAL CONTROL OF GEARBOXES WITH HAND-OPERATED SELECTION AND ENGAGEMENT OF GEARS FOR MOTOR VEHICLES

Abstract: The device for the sequential control of gearboxes with hand-operated selection and engagement of gears for motor vehicles comprises: a drum (11, 26, 29) equipped with cams (12, 30) for the control of the forks (1) of the corresponding groups of gearwheels; an angle selector (15, 16); studs (13) for following the said cams, in the motion axial to the said drum, connected to organs actuating the said forks; plates (3, 4) with openings (5) each connected to a respective fork (1) to control the engagement of the group of gearwheels, and has the said actuating organs consisting of cursors (9, 31, 33) and/or forks (7), each bearing one of the said studs (13), axially mobile on at least one pin (10) parallel to the said drum (11, 26, 29) and to the axial pins (2) of the said forks (1), and separate from them; finally, the extremity of each cursor and/or fork features a detent (6, 8) engaging in the opening (5) of the corresponding plate (3, 4) so as render the axial motion to its own stud (13) integral with that of the plate, and hence of the relative fork, to which it is coupled.

Description: DEVICE FOR THE SEQUENTIAL CONTROL OF GEARBOXES WITH HAND-OPERATED SELECTION AND ENGAGEMENT OF GEARS FOR MOTOR VEHICLES The invention concerns a device that enables the driver of a motor vehicle to control sequentially a gearbox of a traditional type, that is, with hand-operated selection and engagement of gears. A gearbox of this type, hereafter referred to as a gate transmission, is generally actuated by a selector lever which, by means of rotations with successive traverses, is capable of selecting and engaging the required gear by shifting the corresponding gearwheels by means of a detent. Devices for the sequential control of gate transmissions are described for example in the European patent application EP 0 616 153 and in the international patent application WO 96/23995. In the said European document a control device is proposed that envisages the use of radial positive cams capable of engaging the gearwheels corresponding to the selected gear thanks to the rota- tion of a camshaft; a jack selector controls the stepwise rotation of the said shaft towards a higher or lower gear in accordance with the command given by the operator using the gear selector lever. This solution presents considerable mechanical complexity, involves the contemporaneous use of all the cams and requires ad- ditional linkages to enable the cams to select and engage the desired gear. In the above-mentioned international patent, on the other hand, a device is described that controls the double actuating levers of a traditional gate transmission in which the rods connected to the said levers are actuated by arms that are in turn connected to a rotating drum featuring a pair of axial cams with which pins on the said arms engage. The stepwise rotation of the drum, achieved in this case too by means of a jack selector, enables each of the two cams constantly to control the position of one of the levers and hence the position of the group of gearwheels of the transmission connected to it. This solution also has the disadvantage of considerable mechanical complexity in that it involves the use of supplementary mechanical organs in addition to the existing con- trols. Also, it can be applied only to transmissions operated by means of a double lever, unless a further mechanical gearbox is introduced to combine the movements of the various actuating organs. What is more, the engine compartment of the vehicle is encumbered with the linkages and the housing of the cam-bearing drum, which has to be positioned externally to and separately from the gearbox itself. The purpose of the present invention is to provide a device for the sequential control of a gate transmission, representing an im- provement over prior art, that is simple and easy to construct, uses few components and can be readily operated in completely automatic mode or with a choice of control mode (automatic or manual) . The invention resolves the said technical problem by adopting a device for the sequential control of gearboxes with manually operated selection and engagement of gears for motor vehicles as described in Claim 1. Further advantageous characteristics are described in the dependent claims . As will be described in more detail below, a control device according to the present invention offers the following advantages: the space taken up in the engine compartment is reduced to a minimum; mechanical performance is optimised; the forks of the gear- wheel groups of the transmission can be actuated directly; operation can be readily automated. The invention will now be illustrated, purely by way of example, with reference to the attached drawings, in which Figure 1 is a partial perspective view of the device for the sequential control of a gate transmission according to the invention; Figure 2 is a view similar to that of Figure 1 but from a different angle and with two of the external forks not represented; Figure 3 is a view of the control device of Figure 1 sectioned diametrically to the drum along the axial cam; Figure 4 is a view along a partially sectioned axial plane of the drum angle selector of the control device of Figure 1; Figure 5 is a perspective view of the control device according to the invention in which the drum is actuated by an electric reduction unit; Figure 6 is a perspective view of the actuator for the sequential control of the drum of the control device; Figure 7 is a perspective view of the jack mechanism positioned internally to the drum of the control device according to the invention; and Figure 8 is a perspective view of a drum for a control device, according to the invention, equipped with a plurality of axial cams, each of which is arranged so as to actuate a single cursor and thus control the respective fork of the gearbox. With particular reference to Figures 1 and 2 to 4, a fork 1, designed to shift a corresponding group of gearwheels of a gate transmission, is rigidly connected to an axial pin 2. The said pin, in order to be integral with the motion of axial traverse (where the term iaxiali will henceforth indicate a direction parallel to the axis of the drum) , is in turn connected to an external toothed plate 3 for the transmission of motion to the respective fork 1. Toothed plates 4, internal to plates 3, are connect- ed to analogous axial pins and forks (not shown in that they are themselves known in prior art) . In plates 3 and 4 there are openings 5 in which the detents 6 and 8 of, respectively, external forks 7 and cursors 9 engage. 10 indicates a pair of axial pins on which forks 7 and cursors 9 slide. A rotating selection drum 11 is equipped with an axial cam 12 with which a plurality of studs 13 (in this case four, one for each fork or cursor) engage with a sliding motion. One end of drum 11 presents splines 15 which, in conjunction with a spring-loaded dog 16, serve to select the angle position, detectable by means of a sensor 17. The opposite end of the drum receives the external commands imparted by the operator using a sequential-type selection lever. In the embodiment illustrated in Figure 5, an external housing 19 of the control device is equipped with a cover 20 on which is mounted a reduction unit 21. In that illustrated in Figure 6, the external housing 22 of the control device supports a lever 23 actuating drum 11, connected to an electromechanical actuator 25, which at each cycle, starting from a central position, is shifted to and fro along a straight path substantially perpendicular to the drum axis. Figure 7, in particular, shows a drum 26 equipped internally with a bi-directional jack 27 of known type, designed to return lever 23 to a central position after each act of selection; 28 indicates an extremity of jack 27. Finally, with reference to Figure 8, a drum 29 is equipped with a plurality of axial cams 30, in this case four, so arranged as to control cursors 31 and 33, respectively, by means of corresponding studs 13, as in the case of drum 11 equipped with a single cam 12 and described with reference to Figures 1 and 2 to 4. 32 indi- cates a detent of cursors 31 and 33, which are preferably placed side by side in pairs on the same axial pin 10. An intermediate detent 34 in the form of an axial check ring is located between the hubs of plates 3 and 4 (only that relating to one of the plates 3 is illustrated) , between which the respective axial pin 2 slides. A pair of springs 35 is placed between the detent 34 and the said hubs to afford elastic coupling between the respective plate and the corresponding unit consisting of a pin 2 and a fork 1. The functioning of the control device according to the invention will now be described. The operator operates sequentially the gearbox selection lever (not illustrated) and, by means of a linkage of known type, acts on lever 23 or on the control micro- switches of the reduction unit 21 or of the electromechanical ac- tuator 25. Both the manual and the interlocked action cause the drum 11, 29 to rotate through one step such that the axial cam 12 or one of the axial cams 30 engage with the corresponding stud 13 to bring about the axial displacement of pin 2 and of the relative fork 1, by means of the whole consisting of the respective cursor 9, 31, 33 or fork 7 and of the respective plate 3 or 4, in such a way that the fork 1 engages the group of gearwheels of the transmission corresponding to the chosen gear. The different circumferential position of the four studs 13 that engage the single axial cam 12 of drum 11 ensures that the said studs are controlled sin- gly, thereby reducing notably the overall dimensions of the mechanism. The angle selector 15,16 determines the precise rotation to be imposed on drum 11, 29 in order to select the gears in a pre- established sequence. The angle sensor 17 reads the rotation of the drum to verify that the rotation imposed on it by means either of the manual command or of the electromechanical actuator 25 is sufficient to guarantee the engagement of the gear selected. In the case in which the control device is equipped with reduction unit 21 or with electromechanical actuator 25, its functioning can be made completely automatic while guaranteeing the possibility of manual intervention. In the case of control by means of a reduction unit, operation must always be electrical and may be effected either manually, by means of a pair of buttons (for the engagement, respectively, of a higher or lower gear) , or automatically, by means of a control box capable of deciding, on the basis of operational parameters of the vehicle, which gear to engage. Finally, the elastic axial coupling afforded by the springs 35 and by the detent 34 located between the pins 2 and the hubs of the plates 3, 4 ensures a more supple operation of the gearwheel groups of the transmission. The main advantages offered by a control device according to the present invention are as follows: firstly, it is extremely compact and can be inserted in the place of the detent lever and linkages generally used in gearboxes of this type; secondly, it can be fitted to gate transmissions already mounted on the vehicle using a kit of replacement components to enable the gearbox to be modified from traditional to sequential : this is particularly advantageous in mass production in that it avoids the need to design new gearboxes directly with sequential control and offers the purchaser the chance of having a vehicle already equipped with a sequential control device in a shorter space of time; thirdly, with regard to known solutions, it has a more direct action in that a single cam, or part of a cam, is always engaged without there being any increase in overall size: the remaining cams or part of cam do no more than position the corresponding cursor in neutral, thereby avoiding errors or malfunctioning of the gearwheel groups of the transmission. Of course, while respecting the principle of the invention, the forms adopted and the details of realisation can vary considerably from what has here been described and illustrated, purely by way of example, without departing from the juridical domain of the in- vention as defined in the attached claims .

Claims: CLAIMS 1. Device for the sequential control of gearboxes with hand- operated selection and engagement of gears for motor vehicles of the type comprising: a drum (11, 26, 29) equipped with at least one cam (12, 30) for the control of a plurality of forks (1) capable of actuating corresponding groups of gearwheels of the said gearbox; an angle selector (15, 16) of the said drum; a plurality of studs (13) following the said at least one cam (12, 30) , therein/and contemporaneously engaged, with axial motion in a direction parallel (10) to the said drum (11, 26, 29) ; means of actuation (2, 3, 4, 7, 9; 2, 3, 4, 31, 33) of the said forks (1) connected to the said studs (13); the said means of actuation, already present in the said gearbox, consisting of primary means (3, 4) of transmission of axial motion to the said forks with a mobile axial pin (2) , each connected to a respective fork (1) ; characterised in that the said means of actuation also consist of secondary means (7, 9; 31, 33) interposed and connected to a respective stud (13) and to a respective primary means of actuation (3, 4) , and integral with them in the axial traverse in a direction parallel (10) to the said drum but distinct from those of the axial pins (2) of the said forks (1) . 2. Device, according to the previous claim 1, characterised in that the said secondary means of actuation consist of cursors (9; 31, 33) and/or forks (7) axially mobile on a respective pin (10) parallel to the axis of the drum (11, 26, 29) . 3. Device, according to one of the previous claims 1 or 2, characterised in that the said primary (3, 4) and secondary (7, 9; 31, 33) means of actuation are connected one with another and con- trol the single fork (1) by a means of engagement (6, 8; 32) in one of the said means of actuation and by a corresponding opening (5) in the other of the said means of actuation. 4. Device, according to the previous claim 3, characterised in that each cursor (9; 31, 33) and/or fork (7) is equipped, so as to constitute the said means of engagement between the primary and secondary means of actuation, with a terminal detent (6, 8) inserted in the opening (5) fashioned in the corresponding primary means (3, 4) of actuation, thereby rendering the axial motion of its own stud (13) integral with that of the said primary means and hence of the relative fork (1) to which it is coupled. 5. Device, according to one of the previous claims from 2 to 4, characterised in that the said cursors (9, 31) and/or forks (7) , constituting the said secondary means of actuation, are disposed in pairs on the same axial pin (10) . 6. Device, according to one of the previous claims from 1 to 5, characterised in that the said secondary means of actuation, cursors (9, 31) and/or forks (7), with the respective studs (13) are offset at an angle in the circumference of the drum (11, 26, 29) within a single axial cam (12) in which they engage. 7. Device, according to one of the previous claims from 1 to 6, characterised in that the drum (11, 29) is set rotating by an electric reduction unit (21) . 8. Device, according to one of the previous claims from 1 to 6, characterised in that the drum (26) of the device interlocks with an electromechanical actuator (25) with reciprocating rod (24) . 9. Device, according to one of the previous claims from 1 to 5, 7 or 8 characterised in that the drum (29) is equipped with a plurality of axially spaced cams (30) , in each of which engages a single stud (13) corresponding to the respective secondary means of actuation (31, 33). 10. Device, according to one of the previous claims, charac- terised in that, in the above means of actuation, there is an axial elastic connection (32, 33, 34) of the corresponding fork (1) to the said primary means of actuation (3, 4) . 11. Kit for modification of the control of a gearbox with hand-operated selection and engagement of gears for motor vehicles, comprising a device for the sequential control of the said gearbox according to any one of the previous claims . 12. Motor vehicle, equipped with a gearbox with hand-operated selection and engagement of gears, comprising a device for the sequential control of the said gearbox according to one of the previous claims from 1 to 11. AMENDED CLAIMS [received by the International Bureau on 15 January 2002 (15.0102); original claims 1-12 replaced by amended claims 1-8 (3 pages)] 1. Device for the sequential control of gearboxes with hand- operated selection and engagement of gears for motor vehicles, that may be assembled as substitute of the hand operated mechanism, of the type comprising: - a drum (11, 26, 29) equipped with at least one cam (12, 30) for the control of a plurality of forks (1) capable of actuating corresponding groups of gearwheels of the said gearbox; - an angle selector (15, 16) of the said drum; - a plurality of studs (13) following the said at least one cam (12, 30) , therein/and contemporaneously engaged, with axial motion in a direction parallel (10) to the said drum (11, 26, 29) ; - means of actuation (2, 3, 4, 7, 9; 2, 3, 4, 31, 33) of the said forks (1) connected to the said studs (13); - the said means of actuation, already present in the said gearbox, consisting of primary means (3, 4) of transmission of axial motion to the said forks with a mobile axial pin (2) , each connected to a respective fork (1) ; characterised in that - the said means of actuation also consist of secondary means (7, 9; 31, 33) interposed and connected to a respective stud (13) and to a respective primary means of actuation (3, 4), and integral with them in the axial traverse in a direction parallel (10) to the said drum but distinct from those of the axial pins (2) of the said forks (1) ; - the said secondary means of actuation consist of cursors (9; 31, 33) and/or forks (7) axially mobile on a respective pin (10) parallel to the axis of the drum (11, 26, 29); - the said primary (3, 4) and secondary (7, 9; 31, 33) means of actuation are connected one with another and control the single fork (1) by a means of engagement (6, 8; 32) in one of the said means of actuation and by a corresponding opening (5) in the other of the said means of actuation; - so as to constitute the said means of engagement between the primary and secondary means of actuation, is provided a terminal detent (6, 8) inserted in the opening (5) fashioned in the corresponding primary means (3, 4) of actuation, thereby rendering the axial motion of its own stud (13) integral with that of the said primary means and hence of the relative fork (1) to which it is coupled. 2. Device, according to the previous claim, characterised in that the said cursors (9, 31) and/or forks (7) , constituting the said secondary means of actuation, are disposed in pairs on the same axial pin (10) . 3. Device, according to one of the previous claims 1 or 2 , characterised in that the said secondary means of actuation, cur- sors (9, 31) and/or forks (7), with the respective studs (13) are offset at an angle in the circumference of the drum (11, 26, 29) within a single axial cam (12) in which they engage. 4. Device, according to one of the previous claims from 1 to 3, characterised in that the drum (11, 29) is set rotating by an electric reduction unit (21) . 5. Device, according to one of the previous claims from 1 to 3, characterised in that the drum (26) of the device interlocks with an electromechanical actuator (25) with reciprocating rod (24) . 6. Device, according to one of the previous claims, characterised in that, in the above means of actuation, there is an ax- ial elastic connection (32, 33, 34) of the corresponding fork (1) to the said primary means of actuation (3, 4) . 7. Kit for modification of the control of a gearbox with hand-operated selection and engagement of gears for motor vehi- cles, comprising a device for the sequential control of the said gearbox according to any one of the previous claims. 8. Motor vehicle, equipped with a gearbox with hand-operated selection and engagement of gears, comprising a device for the se- quential control of the said gearbox according to one of the previous claims from 1 to 6.

Inventors: BIGI MAURIZIO, BIGI, MAURIZIO
Applicants: AUTOMAC S A S DI BIGI ING MAUR, BIGI MAURIZIO, AUTOMAC S.A.S. DI BIGI ING. MAURIZIO, BIGI, MAURIZIO
Application year: 2001
Main classification: F16H63
IPC codes: F16H61, F16H63