WO2004041582A1

WO2004041582A1 - Electrochemical actuator for the automation of a mechanical gear unit of motor vehicles

Info

Publication number: WO2004041582A1
Application number: PCT/IT2002/000702
Authority: WO
Inventors: Wanni Albertini
Original assignee: SME Srl; Digitek SpA
Current assignee: SME Srl; Digitek SpA
Priority date: 2002-11-07
Filing date: 2002-11-07
Publication date: 2004-05-21
Anticipated expiration: 2005-05-07
Also published as: AU2002353526A8; AU2002353526A1

Abstract

Un attuatore elettromeccanico per l'automatizzazione di un cambio meccanico di veicoli a motore comprende un motore elettrico (1) ed un dispositivo (2), tra i quali si trova generalmente un motoriduttore (13), per transformare il moto rotatorio impartito dal motore elettrico (1) in un moto traslatorio degli organi di comando (3, 4) di frizione e cambio. Il dispositivo (2) comprende un tamburo (5), rotante sotto l'azione del motore elettrico (1) e provvisto de scanalature (6, 7) circonferenziali, nelle quali si impegnano mezzi di interferenza (36, 47) rispettivamente solidali agli organi di comando (3, 4) di frizione e cambio, in modo che quando il tamburo (5) ruota gli organi di comando (3, 4) di frizione e cambio traslino nella direzione dell'asse del tamburo (5).

Description

ELECTROMECHANICAL ACTUATOR FOR THE AUTOMATION OF A

MECHANICAL GEAR UNIT OF MOTOR VEHICLES

Description

Technical field The present invention relates to an electromechanical actuator for the automation of a mechanical gear unit of motor vehicles .

There is a very pressing need in the motoring sector to use remote operating means which allow, on the one hand, unification, in terms of design and operation, of the clutch and gear control system and, on the other hand, if necessary, dual operation - i.e. either manual or automatic

- of these devices.

Prior art The known manual actuating devices envisage mainly the use of actuators consisting of hydraulic cylinders in which the movement of the pistons is determined by variations in the pressure acting thereon.

Other mechanical actuators used for operation of the clutch in the motorcycle or motor car sector allow, by means of lever systems and/or rack-and-pinion transmissions, displacement of the clutch plate; furthermore, a hydraulic actuating system operated directly by the rider or driver by means of hand or pedal-operated levers is known, said system comprising a pump, connected to the actuating lever, which controls a hydraulic cylinder which acts directly on the rod of the clutch plate.

A more recently used solution is one where the abovementioned controls may act directly on the thrust bearing as a result of integration of the latter with the hydraulic cylinder.

Operating by means of remote control, so as to be certain of correct operation, it is appropriate that the gear control system should at the same time also perform actuation of the clutch: the abovementioned devices, however, have design and installation features such as not to allow both manual and automatic operation.

In the motor car sector, devices for actuating the clutch and gear operating system which use electric motors are also known: in some electric clutch actuators, however, it is required to reverse the movement of the electric motor, such that the actuating cycle of the clutch is dependent upon the direction of rotation and also said reversal is to the detriment of rapid operation of the actuator; in other applications, electric motors for controlling the gear unit, combined with reducer mechanisms, act directly on the gear engaging drum or on the gear-unit actuating rod during sequential gear changes.

In other devices, the number of components which must be used and the operational complexity of the mechanisms results in a high probability of seizures and drastically reduces the reliability of these devices and the overall mechanical performance. In these devices, moreover, the play in mating between the various parts tends to increase the wear of said parts: this may create serious problems for the electronic control components as regards correct operation of the device in question. Summary of the present description

The object of the present invention is therefore that of eliminating the abovementioned drawbacks.

The invention, as it is characterized by the claims, achieves the object by means of a device for converting the rotary movement imparted by the electric motor into a translatory movement of the clutch and gear actuating members, comprising a rotating drum directly connected to these actuating members and therefore automatically able to synchronize operation of the clutch and gear unit.

The main advantage obtained by means of the present invention consists essentially in the fact that the number of mechanical parts necessary for transmitting the movement from the electric motor to the clutch and gear unit is reduced to a minimum, consequently limiting the costs of both construction and maintenance and the possible causes of malfunctioning. Moreover, the device can also be installed in vehicles which are already on the roads. Brief description of the drawings

Further advantages and characteristic features of the invention will emerge more clearly from the detailed description which follows, with reference to the accompanying drawings, which show a non-limiting example of embodiment in which:

- Figures 1 and 2 show lateral perspective views of a first embodiment of the invention, rotated through 180° with respect to each other;

- Figure 3 shows a plan view and a front view of the embodiment of the invention according to Figures 1 and 2;

- Figures 4 and 5 show lateral perspective views of a second embodiment of the invention, rotated through 180° with respect to each other;

- Figure 6 shows a plan and a front view of the embodiment of the invention according to Figures 4 and 5;

- Figures 7 and 8 show lateral perspective views of a third embodiment of the invention, rotated through 180° with respect to each other;

- Figure 9 shows a plan view and a front view of the embodiment of the invention according to Figures 7 and 8. Detailed description of the preferred embodiments

As can be seen from the figures, the invention relates to an electromechanical actuator for automation of the mechanical gear unit of motor vehicles, comprising an electric motor (1) and a device (2) for converting the rotary movement imparted by the electric motor (1) into a translatory movement of the clutch and gear actuating members (3,4). The device (2) used here comprises a drum (5) , rotating owing to the action of the electric motor (1) and provided with circumferential grooves (6,7) inside which interference means (36,47) respectively integral with the clutch and gear actuating members (3,4) engage so that, when the drum (5) rotates, the clutch and gear actuating members translate in the direction of the axis of the drum

(5) . The presence of a motor reducer (13) able to regulate the angular velocity of the drum (5) is generally envisaged between the electric motor (1) and the device (2) . Depending on certain parameters, a single gear change may correspond to a rotation of the drum (5) of variable amplitude .

Although the figures show only cases where rotations of the drum through 360° correspond to each gear change, it is possible to obtain the same effect with rotations of the drum (5) through 180°, 90°, or other amplitude, by merely multiplying the number of grooves in the drum (5) . This is mainly dependent upon the specifically designed motor reducers (13) which are commercially available and on the dimensions of the drum (5) ; in fact, on the one hand the reduction in the angle of rotation of the drum (5) corresponding to a gear change results in an increase in the dimensions of the drum (5), so that the linear extension of the grooves have the right length; on the other hand, the use of motor reducers (13) characterized by a high reduction ratio in the angular velocity suggests the use of drums (5) having small dimensions.

In the examples illustrated here and relating to a situation where a single gear change corresponds to a rotation of the drum through 360°, the interference means (36,47) which engage in the grooves (6,7) of the drum (5) comprise a first boss (36) integral with the clutch actuating member (3) and a second boss (47) integral with the gear actuating member (4) , which are preferably provided with a bearing (10) able to reduce the friction.

The groove (6) inside which the boss (36) integral with the clutch actuating member (3) engages comprises a loop (6a) - corresponding to the rest position of the clutch, conventionally called "closed clutch" position which is formed symmetrically with respect to said position, so that displacement of the clutch actuating member (3) is independent of the direction of rotation of the drum (5) . When the electric motor (1) is not under strain, the boss (47) integral with the gear actuating member (4) also remains in its rests position which is situated at a distance of 180° from that of the boss (36) integral with the clutch actuating member (3) .

The groove (7) inside which the boss (47) integral with the gear actuating member (4) engages comprises, instead, two separate tracks (7a, 7b) which are identical to each other, but slightly offset with respect to each other. As a result, they may be made accessible alternatively so that the displacement, in one direction or the other, of the gear actuating member (4) depends on the direction of rotation of the drum (5) . A first track (7a) comprises an access ramp (7') which is accessible solely during rotation of the drum (5) able to effect a gear change from a lower gear to a higher gear, while a second track (7b) comprises an access ramp (7'') which is accessible only during a rotation of the drum (5) able to perform a gear change from a higher gear to a lower gear.

Further shaping of the drum (5) helps ensure that the device according to the present invention is able to satisfy the most frequent requirements of potential users; in particular, these requirements relate mainly to the possibility of combining with automatic control also direct control by the driver as well as driving-related features such as the possibility of performing multiple gear changes, i.e. between non-consecutive gears, or the possibility of changing gears without operating the clutch, as performed by more expert drivers or riders .

In order to allow direct control by the driver, it is necessary for the gear actuating member (4) to be able to perform a translatory movement also when there are no rotations of the drum (5) : for this purpose, the drum (5) itself comprises means (8) for centring the gear actuating member (4) in the rest position: these means, as can be seen in Figures 1, 4 and 7, comprise a recess (81) oriented along the axis of the drum (5) and centred on the rest position of the gear actuating member (4), so as to allow said actuating member (4) to perform movements corresponding to the execution of gear changes by means of direct manual operation.

The possibility of performing multiple gear changes is instead obtained by means of a device (9) for locking the clutch actuating member (3) following translation thereof so as to bring the clutch into a position conventionally called "open clutch" position. Whatever the device (9) used, it is nevertheless necessary for the groove (6) in the drum (5) , inside which the boss (36) integral with the clutch actuating member (3) engages, to comprise a section (6b) which is parallel to the loop (6a) and inside which this boss (36) remains engaged, while the drum (5) continues to rotate and the clutch actuating member (3) is locked. In the example shown here in the figures, the device (9) comprises means for mutual interference between the clutch actuating member (3) and the drum (5), which can be activated by the driver: these means comprise a seat (30) , which is located on the clutch actuating member (3) , and a movable pin (50) , integral with the drum (5) , matching this seat (30) and able to engage with it upon actuation by the driver, having the possibility of doing so only in an "open clutch" situation since only in this condition are the seat (30) and the pin (50) facing each other. To be sure that the clutch actuating member (3) is brought back into its rest position when the device (9) is not activated, i.e. that the boss (36) engages with the loop (6a) instead of with the section (6b) parallel thereto, the presence of a suitably prestressed return spring (15) is envisaged.

Similarly, a device (11) for locking the clutch actuating member (3) in the rest position allows gear to be changed without operating the clutch: for this purpose, it is necessary for the loop (6a) to extend parallel to the remainder of the groove (6) over the whole circumference of the drum (5) so as to house the boss (36) also while gear is being changed in the "closed clutch" condition. This device (11) comprises means (53a) for mutual interference between the clutch actuating member (3) and the drum (5) , which can be activated by the driver: they comprise a seat (30a) , located on the clutch actuating member (3) , and a movable pin (50), integral with the drum (5), matching said seat (30a) and suitable for engagement therewith upon operation by the driver only when in a "closed clutch" situation, since only in this condition are the seat (30a) and the pin (50) facing each other.

Obviously, a single pin (50) integral with the drum (5) is able to perform both the functions described above, as illustrated in Figures 7 to 9. The apparatus also comprises at least one sensor (10) able to detect the angular position of the drum (5) . In the example shown, said sensor consists of a potentiometer (10) connected to an electronic control unit - not shown - able to manage the gradual mechanical approach movement of the clutch into its rest position.

Finally, the presence of at least one sensor (12), able to detect the number of revolutions of the electric motor (1), may be of certain use. This sensor (12) may be used to acquire direct information regarding correct operation of the electric motor (1) as well as verify the presence of any play between the latter and the motor reducer (13) . By way of example, the sensor (12) has been shown in Figures 1 to 3 and 7 to 9 as an encoder incorporated inside the motor reducer (13) positioned between the electric motor (1) and the drum (5) ; while, in Figures 4 to 6, it is shown as a plurality of magnetic sensors (12') positioned between the electric motor (1) and the motor reducer (13) .

It is obvious in the light of the present description that the constructional design of the entire actuator may envisage various embodiments in which the relative position of the various parts forming it is modified: for example, the electric motor (1) may be positioned in parallel with the drum (5) so that the gear unit has more compact overall dimensions; or, different shaping of the drum (5) may allow different positioning of the actuating members which in certain applications could also be greater than two in number.

The essential operation of this actuator may be described as follows: when the driver of the vehicle intends changing gear, power is drawn from the electric motor (1) ; the drum (5) is made to rotate, causing displacement of the bosses (36,47) along the grooves (6,7) inside which they are engaged. The boss (36) integral with the clutch actuating member (3) comes out of the loop (6a) and causes a translatory movement, along the axis of the drum (5) , of the clutch actuating member (3) which produces an "open clutch" situation. Only at this point does the boss (47) integral with the gear actuating member (4) enter into one of the two tracks (7a, 7b) of the groove (7) inside which it is engaged, causing translation of the gear actuating member (4) in the direction of the axis of the drum (5) . During the time necessary for effecting a gear change, the drum (5) performs a complete (or a half, or a quarter) revolution, the potentiometer (10) , which detects the angular position thereof, warns an electronic control unit when the drum (5) is close to returning into the start of cycle position and the control unit brings back the clutch gently into the closed position, while the boss (36) returns into its rest position.

The invention thus conceived may be subject to numerous modifications and variations, all falling within the scope of the inventive idea. Moreover, all the details may be replaced by technically equivalent elements. In practice, obviously modifications and/or improvements are possible, nevertheless within the scope of the following claims .

Claims

CLAIMS 1. Electromechanical actuator for the automation of a mechanical gear unit of motor vehicles, comprising an electric motor (1) and a device (2) for converting the rotary movement imparted by the electric motor (1) into a translatory movement of the clutch and gear actuating members (3,4), characterized in that said device (2) comprises a drum (5) rotating as a result of the action of the electric motor (1) and provided with circumferential grooves (6,7) inside which interference means (36,47) respectively integral with the clutch and gear actuating members (3,4) engage so that, when the drum (5) rotates, the clutch and gear actuating members (3,4) translate in the direction of the axis of the dr'um (5) .

2. Actuator according to Claim 1, characterized in that a single gear change corresponds to a rotation of the drum (5) through 360°.

3. Actuator according to Claim 1, characterized in that a single gear change corresponds to a rotation of the drum (5) through 180°.

4. Actuator according to Claim 1, characterized in that a single gear change corresponds to a rotation of the drum (5) through 90°.

5. Actuator according to Claim 1, characterized in that the interference means (36,47) comprise a first boss (36) integral with the clutch actuating member (3) and a second boss (47) integral with the gear actuating member (4).

6. Actuator according to Claim 1, characterized in that the interference means (36,47) comprise at least one bearing (10) able to reduce the friction.

7. Actuator according to Claim 5, characterized in that the groove (6) inside which the boss (36) integral with the clutch actuating member (3) engages comprises a loop (6a) corresponding to the rest position and formed symmetrically with respect to said position, so that displacement of the clutch actuating member (3) is independent of the direction of rotation of the drum (5) .

8. Actuator according to Claim 5, characterized in that the groove (7) inside which the boss (47) integral with the gear actuating member (4) engages comprises two separate tracks (7a, 7b) which are alternatively accessible so that displacement of the gear actuating member (4) is dependent on the direction of rotation of the drum (5) .

9. Actuator according to Claim 8, characterized in that a first track (7a) comprises an access ramp (7") which is accessible only during rotation of the drum (5) able to effect a gear change from a lower gear to a higher gear, while a second track (7b) comprises an access ramp (7'') which is accessible only during rotation of the drum (5) able to effect a gear change from a higher gear to a lower gear.

10. Actuator according to Claim 1, characterized in that the drum (5) comprises means (8) for centring the gear actuating member (4) in the rest position.

11. Actuator according to Claim 10, characterized in that the centring means (8) comprise a recess (81) oriented along the axis of the drum (5) and centred on the rest position of the gear actuating member (4) so as to allow said actuating member (4) to perform movements corresponding to the execution of gear changes by means of direct manual operation.

12. Actuator according to Claim 7, characterized in that it comprises a device (9) for locking the clutch actuating member (3) following its translation thereof so as to bring the clutch into the open position, in order to perform multiple gear changes, said groove (6) comprising a section (6b) which is parallel to the loop (6a) and inside which the boss (36) integral with the clutch actuating member (3) remains engaged, while changing between non- consecutive gears is performed.

13. Actuator according to Claim 12, characterized in that the device (9) comprises means (53) for mutual interference between the clutch actuating member (3) and the drum (5) , which can be activated by the driver.

14. Actuator according to Claim 13, characterized in that said means (53) comprise a seat (30), located on the clutch actuating member (3) , and a movable pin (50) matching said seat (30) and able to engage with said seat (30) upon actuation by the driver, said seat (30) and said pin (50) facing each other only when the clutch is in the open position.

15. Actuator according to Claim 7, characterized in that it comprises a device (11) for locking the clutch actuating member (3) in the rest position, in such a way as to change gear without operating the clutch, said loop (6a) extending parallel to said groove (6) over the whole circumference of the drum (5) so as to house the boss (36) also while gear is being changed with the clutch in the rest position.

16. Actuator according to Claim 15, characterized in that the device (11) comprises means (53a) for mutual interference between the clutch actuating member (3) and the drum (5) , which can be activated by the driver.

17. Actuator according to Claim 16, characterized in that said means (53a) comprise a seat (30a) , located on the clutch actuating member (3) , and a movable pin (50) matching said seat (30a) and able to engage with said seat

(30a) upon operation by the driver, said seat (30a) and said pin (50) facing each other only when the clutch is in the rest position.

18. Actuator according to Claim 1, characterized in that it comprises a return spring (15) able to bring the clutch actuating member (3) into the rest position when the device (9) is not activated.

19. Actuator according to Claim 1, characterized in that it comprises at least one sensor (10) able to detect the angular position of the drum (5) .

20. Actuator according to Claim 19, characterized in that said sensor (10) consists of a potentiometer.

21. Actuator according to Claim 1, characterized in that it comprises at least one sensor (12) , able to detect the number of revolutions of the electric motor (1) .

22. Actuator according to Claim 21, characterized in that said sensor (12) comprises an encoder incorporated inside a motor reducer (13) positioned between tl^e electric motor (1) and the drum (5) .

23. Actuator according to Claim 21, characterized in that said sensor (12) comprises a plurality of magnetic sensors (12') positioned between the electric motor (1) and a motor reducer (13) located ahead of the drum (5) .

24. Actuator according to Claim 1, characterized in that the electric motor (1) is positioned in parallel with the drum (5) so that the gear unit has more compact overall dimensions.

25. Actuator according to the preceding claims and in accordance with that described and illustrated with reference to the figures of the accompanying drawings and for the objects mentioned.