DE19917215A1 - Electric motor control arrangement for vehicle automated gearbox-clutch unit has electronically commutated electric servomotor with electrical commutation device - Google Patents

Abstract

The control arrangement has an electric control motor supplied by the on-board supply and coupled or able to be coupled on the driven side to an element (27,43) of the gearbox-clutch unit (5,7) to be actuated. The motor (25,33,35) is an electronically commutated electric servomotor with an electrical commutation device (31,37) for commutating the motor drive currents.

Description

The invention relates to an electromotive actuator arrangement for a Automated transmission-clutch assembly of a vehicle, with one fed from an on-board network of the vehicle and on the output side with a Coupled or actuated organ of the transmission-clutch assembly connectable electric servomotor.

In automated transmission-clutch assemblies are increasing Electromotive actuators are used, as compared to hydraulic actuators require less design effort, are therefore cheaper and also enable higher efficiencies. So far, however, those with electromotive actuators have been problematic achievable shift speeds in manual transmissions. Fast Shifting operations are desirable in order to offer a high level of driving comfort. While with hydraulic actuators switching times of less than 200 ms for a complete switching process, i.e. disengagement, Gear changes and clutch engagement are possible, allow electromotive Actuators so far only have switching times, which in the best possible case are around 500 ms lie. The clumsiness of the previous electromotive Actuators have the following reason: To actuate the selector shaft of a Manual gearbox or the release of a friction clutch must comparatively high actuating forces are applied. For example the force required to adjust the selector shaft easily in 1200 Newton range, especially if the resistance overcome a synchronization mechanism of the manual transmission  must become. It therefore becomes a correspondingly powerful servomotor needed. In order to meet the performance requirements, So far, only DC brush motors have been used, however by their comparatively high moment of inertia and that with the given performance requirements relatively high weight just a bad one Offer dynamics and also build comparatively large volumes. Disadvantageous on DC brush motors is also due to brush wear conditional maintenance.

The object of the invention is therefore an electromotive Actuating arrangement of the type described in such a way that faster shift times of the gear-clutch assembly can be achieved.

In solving this problem, the invention is based on the consideration that in modern vehicle construction increasingly to higher electrical system voltages than the previously used 12 or 24 V is thought. There will be advantages especially in improved efficiencies of the various seen electrical and electronic components of the vehicle. Special attention is paid to on-board electrical systems, the different vehicle electrical system voltages supply, one of which is still 12V, but others higher lie, for example at 42 V or above. Please refer to this on an article "Future energy supply systems in motor vehicles" by R. Schöttle, D. Schramm, J. Schenk in VDI Report No. 1287, 1996, pages 295-317.

To solve the problem, the invention now proposes that the Servomotor is designed as an electronically commutated servo motor and An electronic commutation of the driver currents of the servomotor Commutation device is provided. Servomotors are designed that they have a low moment of inertia and a accordingly have high dynamics. They show very short Start-up times and enable correspondingly quick adjustment processes. At  Design for higher operating voltages than the usual ones Vehicle electrical system voltages can now also be sufficiently powerful Servomotors are provided that are designed for use in automated Gear coupling assemblies are suitable and the required there can apply comparatively high actuating forces. By an increased Operating voltage of more than 30 V, for example about 40 V, 80 V or 100 V, the performance of the servo motors can be increased, without having to increase their power consumption. This enables small Maintain wire cross sections of the winding wires and the electrical ones Losses, the total weight and the size are accordingly small hold.

Because of the electronic commutation fall in DC motors also mechanical friction losses away, which on the brushes from DC brush motors occur. This also promotes high dynamics of the servo motor and helps achieve the desired high switching speeds to reach.

The servomotor can be designed as a brushless DC motor. Alternatively, it can be designed as an AC motor. In the latter case training as a synchronous motor is also possible Training as an asynchronous motor.

The actuating arrangement according to the invention can of course also in Connection to electrical systems are used, the voltage level moved in the usual range of 12 or 24 V. To nevertheless the to benefit from the advantages of higher motor operating voltages mentioned above , it is then recommended that the commutation device Upstream voltage converter, which is a lower one Converts the vehicle electrical system voltage to a higher engine operating voltage. For the Installation in the vehicle, it is assembly technology favorable if the  Voltage converter with the commutation device and / or the Actuator is combined into a structural unit.

The organ of the gear-clutch assembly to be actuated can in particular be a gear shift shaft or a clutch release.

The invention will now be described with reference to the accompanying drawings explained. They represent:

Fig. 1 shows schematically an automated gear-clutch assembly in a drive train of a vehicle having the required mechanical and electrical components for its actuation,

Fig. 2a shows a first variant of an actuator for actuating a transmission shift shaft,

Fig. 2b is a view in the direction of arrow 11 of FIG. 2a,

Fig. 3 shows a second variant of an actuator for actuating a transmission shift shaft,

Fig. 4 shows a third variant of an actuator for actuating a transmission shift shaft,

Fig. 5a shows a fourth variant of an actuator for actuating a transmission shift shaft, and

Fig. 5b is a view in the direction of arrow V of Fig. 5a.

In Fig. 1, 1 designates an internal combustion engine having a crankshaft rotatably connected to the rotor of an electrical machine 3, which is in turn connected via a friction clutch 5 having a power shift gear 7. The latter, which is an automated manual transmission, is in a torque-transmitting drive connection with driven wheels of a vehicle, not shown. The electric machine 3 works permanently as a generator when the vehicle is in motion. To start the internal combustion engine 1 , it can also be operated by a motor. A converter 11 controlled by a central control unit 9 commutates the possibly multi-phase driver or generator currents of the electrical machine 3 and feeds the generator currents generated in the generator mode of the electrical machine 3 into a storage battery 13 of a DC vehicle electrical system, generally designated 15 . In the exemplary embodiment shown in FIG. 1, this electrical system 15 has two branches of different voltage levels, namely a low-voltage branch 17 and a medium-voltage branch 19 . The voltage level of the low-voltage branch 17 is, for example, 12 V. The low-voltage branch 17 serves to supply energy to small electrical consumers who need a low-voltage supply, for example incandescent lamps of a vehicle lighting system. The voltage level of the medium voltage branch 19 is higher and is, for example, about 40 V, about 80 V or even over 100 V. Electrical consumers 23 are connected to the medium voltage branch 19 and offer efficiency or speed advantages at higher supply voltages. For example, an electrical brake system or an electromechanical valve control can be supplied from the medium-voltage branch 19 .

An electric servomotor 25 is also supplied from the medium-voltage branch 19 and serves as the driving part of a clutch actuator 29 engaging a clutch release mechanism 27 . The electric motor 25 is an electronically commutated servo motor and can be designed as a brushless DC motor, but also as an AC motor. Its driver currents are commutated by an electronic commutation device 31 , the electrical valves of which are also controlled by the control unit 9 .

Furthermore, two electrical servomotors 33 and 35 are supplied from the medium-voltage branch 19 of the vehicle electrical system 15 via a further electronic commutation device 37 , of which the servomotor 33 forms the driving part of a first gear actuator 39 and the servomotor 35 serves as the driving part of a second gear actuator 41 . The two transmission actuators 39, 41 engage on a shift shaft 43 of the transmission 7 and enable a longitudinal adjustment of the control shaft 43 along a so-called switching path and a rotational displacement of the control shaft 43 about its longitudinal axis along a so-called Wählwegs. By suitable mutual coordination of the longitudinal and rotary adjustment of the selector shaft 43 , any gear changes of the manual transmission 7 can be effected with or without a gate change. For this purpose, the commutation device 37 allows the electric motors 33 , 35 to be controlled independently of one another. The electric motors 33 , 35 are also designed as electronically commutated servomotors, with brushless direct current motors as well as alternating current motors also being suitable.

If the driver of the vehicle wants to change gear, he actuates a shift stick 45 by hand , the actuation of which is detected by a sensor 47 and reported to the control unit 9 as an electrical signal. This then controls the servomotor 25 of the clutch actuator 29 and causes the friction clutch 5 to be disengaged. The control unit 9 then brings about the desired gear change by suitable actuation of the transmission actuators 39 , 41 , whereupon the friction clutch 5 is engaged again by means of the clutch actuator 29 . By using highly dynamic servomotors for the servomotors 25 , 33 , 35 , the entire switching process can easily be carried out in 150 ms or even faster.

In the event that the vehicle electrical system 15 does not provide different voltage levels and is only designed for a voltage of 12 V or that at least some of the servomotors 25 , 33 , 35 are to be operated with an even higher voltage than that of the medium-voltage branch 19 , the a commutation device (in FIG. 1 the commutation device 31 ) can be connected upstream of a direct voltage converter 49 which transforms the direct voltage of the medium voltage branch 19 to the desired level.

The travel of the actuators 29 , 39 , 41 can be determined with the aid of rotor position sensors integrated in the electric motors 25 , 33 , 35 and, if necessary, additional speed sensors.

In the other figures, the same or equivalent components as in FIG. 1 are provided with the same reference numerals, but supplemented by a lower case letter. Unless otherwise stated below, reference is made to the above explanations for FIG. 1 for the explanation of these components.

In FIGS. 2a and 2b can be seen an actuator arrangement for the switching shaft 43 a of the FIG. Gearbox shown 1, wherein the switching path (shown by an arrow 51 a) and the selection path (shown by an arrow 53 a) of the shift shaft 43 a can be introduced independently of each other by one of the actuators 39 a, 41 a. The servomotors assigned to the two actuators 39 a, 41 a are not shown in FIGS. 2a and 2b. Each of the actuators 39 a, 41 a has a linear slide 55 a or 57 a, of which the linear slide 55 a is linearly movable in the direction of an arrow 59 a on a first guide device 61 a fixed to the vehicle, for example by means of rolling elements. The other linear slide 57 a is saddled on the linear slide 55 a and guided in a linearly movable manner by means of a second guide device 63 a fixedly attached to the linear slide 55 a, again, for example, by means of rolling elements, namely in a direction 59 a of the linear slide 55 a orthogonal direction, which is indicated in Fig. 2b by an arrow 65 a. The two linear slides 55 a, 57 a thus form a cross slide system.

In the upper carriage 57 a with the switching shaft 43 a fixedly connected lever piece 67 a is articulated. For this purpose, the lever piece 67 a engages with a ball joint head 69 a in a recess 71 a in the upper carriage 57 a.

The switching path of the switching shaft 43 a can be realized by adjusting the slide 55 a in the direction of arrow 59 a. Independently of this, the selection path of the control shaft 43 a can be brought about by moving the carriage 57 a relative to the carriage 55 a in the direction of the arrow 65 a. During this adjustment of the slide 57 a, the lever piece 67 a is pivoted in the manner shown in FIG. 2 b, which results in a rotary adjustment of the control shaft 43 a.

It is understood that between the carriage 55 a, 57 a and the servo motors, not shown in FIGS . 2a and 2b, suitable gears, e.g. B. spindle drives will be mounted to implement the rotary movement of the output shafts of the servomotors in a linear movement of the carriage 55 a, 57 a.

The control shaft 43 a is guided in an actuator housing 73 a longitudinally and rotatably, for example by means of a ball guide bush.

The actuator arrangement shown in FIGS. 2a and 2b is characterized in that it allows very high positioning accuracies and that high accelerations and short positioning times can be achieved by the linear slide principle. In addition, the actuator arrangement can be designed in a compact design.

In the actuator arrangement of FIG. 3, the switching path of the control shaft 43 b is initiated (in the direction of arrow 51 b) via the servomotor 33 b of the actuator 39 b. The latter comprises a worm gear 77 b which is fixedly attached to a motor output shaft 75 b and which meshes with a worm gear 79 b (or a worm gear segment), which in turn is coaxially and non-rotatably connected to a spur gear 81 b (or a spur gear segment). This spur gear 81 b meshes with a rotating rack profile 83 b, which is formed on the outer circumference of a rotationally fixed shaft piece 85 b connected to the control shaft 43 b. The shaft piece 85 b has at its end facing the servomotor 35 b an axial recess 87 b, into which an output shaft 89 b of the servomotor 35 b projects. The shaft piece 85 b is longitudinally displaceable relative to the motor output shaft 89 b, but is non-rotatably coupled to the motor output shaft 89 b. For the rotationally fixed coupling, a feather key 91 b, for example, can be used between the shaft piece 85 b and the motor output shaft 89 b. It is also conceivable to design the portion of the motor output shaft 89 b projecting into the axial recess 87 b with a multi-spline profile and to design the axial recess 87 b with a corresponding counter-spline profile.

The shaft piece 85 b is, for example, guided in a longitudinally and rotationally displaceable manner by means of ball guide bushings at the points designated by 93 b in FIG. 3.

The selection path of the control shaft 43 b (represented by the rotary arrow 53 b) is initiated via the servomotor 35 b. The rotationally fixed connection of the shaft piece 85 b with the motor output shaft 89 b causes the selector shaft 43 b to be rotated by the desired angle of rotation. Independently of this, a longitudinal adjustment of the control shaft 43 b can be brought about by actuating the servomotor 33 b. The shaft piece 85 b slides on the motor output shaft 89 b of the servomotor 35 b.

An advantage of the actuator arrangement shown in FIG. 3 is its simple construction and its simple operating principle. It manages with a comparatively small number of components, which keeps manufacturing costs low. It enables short positioning times and high positioning accuracy, the latter because of the stable power transmission points in the power transmission path from the actuators 33 b, 35 b to the control shaft 43 b (no joints).

In the actuator arrangement shown in FIG. 4, the switching path of the switching shaft 43 c (along the arrow 51 c) is initiated by the actuator 39 c. This comprises a worm gear 95 c with a worm gear 97 c attached to the output shaft 75 c of the actuator 39 c associated with the actuator, not shown here, and a worm gear segment 99 c meshing with the worm gear 97 c, which sits on the selector shaft 43 c. The selector shaft 43 c is designed in the area of the worm gear segment 99 c with an external part thread in which a complementary internal part thread of the worm gear segment 99 c engages. When the motor output shaft 75 c rotates, the worm gear 95 c and the non-self-locking thread engagement of the worm gear segment 99 c with the selector shaft 43 c cause a longitudinal adjustment of the selector shaft 43 c in the direction of the arrow 51 c.

The selection path of the shift shaft 43 c (in the direction of arrow 53 c) is initiated via the actuator 41 c. This comprises a further worm drive 101 c, which is composed of a worm wheel segment 103 c seated on the selector shaft 43 c and a worm wheel 105 c meshing with the worm wheel segment 103 c, which rotatably on the output shaft 89 c of the actuator 41 c assigned to the actuator (here not shown) is attached. The worm gear segment 103 c is longitudinally displaceable on the selector shaft 43 c. For example, the selector shaft 43 c is designed in the area of the worm wheel segment 103 c on its outer circumference with a multi-spline profile which is in non-rotatable but longitudinally displaceable engagement with a complementary inner spline profile of the worm wheel segment 103 c.

If as a result of rotation of the engine output shaft 89 c is a rotational adjustment of the shift shaft 43 is brought c, inevitably, unless countermeasures are taken, because of the threaded engagement between the worm wheel 99 c and the shift shaft 43 c, a longitudinal adjustment of the shift shaft 43 c about. If only a rotary adjustment of the control shaft 43 c is to be effected, the worm drive 95 c must be driven in opposite directions for compensation. To implement the selection path, a simultaneous actuation of the actuators assigned to the two actuators 39 c, 41 c is therefore necessary.

The actuator arrangement of FIG. 4 is characterized by a simple construction and a simple operating principle. It allows high positioning accuracy and, due to the high-helix principle, also acceptable positioning times for the switching path. It manages with a comparatively small number of components and enables a compact design.

In FIGS. 5a and 5b is finally shown an actuator assembly 39 d in which each of the actuators, 41 a d d from the respective actuating motor 33, or 35 d drivable linear slide 107 d and 109 d includes. The two carriages 107 d, 109 d are each guided linearly by a guide device 111 d or 113 d in a direction 115 d orthogonal to the switching path direction 51 d of the switching shaft 43 d. The carriage of the slides 107 d, 109 d on the guide devices 111 d, 113 d can be implemented, for example, by means of roller bodies. It is understood that between the servo motor 33 d and the carriage 107 d and between the servomotor 35 d and the carriage 109 d each a suitable gear, for example a spindle drive, will be arranged, which rotates the output shaft of the servomotor in question in a linear movement converts.

On the selector shaft 43 d, two lever pieces 117 d and 119 d are fixedly attached, of which the lever piece 117 d engages in a guide link 121 d of the slide 107 d which runs obliquely to the guide direction 115 d and obliquely to the shift travel direction 51 d. The lever piece 119 d, on the other hand, engages in a guide link 123 d of the slide 109 d that extends parallel to the switching path direction 51 d.

To implement the switching path of the control shaft 43 d, the servomotor 33 d is actuated, which leads to an adjustment of the slide 107 d in the direction of the arrow 115 d. The engagement of the lever piece 117 d in the inclined guide link 121 d causes an adjustment of the control shaft 43 d in the direction of arrow 51 d, the inclined position of the guide link 121 d being of course chosen such that no self-locking occurs. In order to implement the selection path, that is to say a rotary adjustment of the control shaft 43 d in the arrow direction 53 d, the servomotor 35 d is actuated, which leads to a linear movement of the slide 109 d in the arrow direction 115 d. Because the lever pieces 119 d has d in the guide link 123 in this direction no movement match, the switching shaft 43 is pivoted around its longitudinal axis d. This causes a simultaneous pivoting of the lever piece 117 d engaging in the oblique guide link 121 d. If only a rotary adjustment of the selector shaft 43 d is to be realized, then the servo motor 33 d must also be driven in a compensating manner in order to prevent a longitudinal adjustment of the selector shaft 43 d being effected by the pivoting of the lever piece 117 d.

The actuator arrangement of FIGS. 5a and 5b is characterized by a simple operating principle, short positioning times and a compact design.

It is understood that in the actuator arrangements explained above not both servomotors of electronically commutated servomotors  must be educated. Depending on the force to be exerted, one can of the servomotors, for example by an electric stepper motor, a electric linear motor, a hydraulic cylinder or a hydraulic Swivel motor to be replaced.

Claims (8)

1. Electromotive actuating arrangement for an automated transmission / clutch assembly ( 5 , 7 ) of a vehicle, with an on-board power supply ( 15 ) of the vehicle and on the output side with an element ( 27 , 43 ) of the transmission / clutch assembly to be actuated ( 5 , 7 ) coupled or couplable electric servomotor ( 25 , 33 , 35 ), characterized in that the servomotor ( 25 , 33 , 35 ) is designed as an electronically commutated servomotor and for commutating the driver currents of the servomotor ( 25 , 33 , 35 ) an electronic commutation device ( 31 , 37 ) is provided. 2. Actuating arrangement according to claim 1, characterized in that the servomotor ( 25 , 33 , 35 ) is designed as a brushless DC motor. 3. Actuating arrangement according to claim 1, characterized in that the servomotor ( 25 , 33 , 35 ) is designed as an AC motor. 4. Actuator according to one of claims 1-3, characterized in that the commutation device ( 31 , 37 ) is connected upstream of a lower vehicle electrical system voltage to a higher engine operating voltage voltage converter ( 49 ). 5. Actuator according to claim 4, characterized in that the voltage converter ( 49 ) with the commutation device ( 31 , 37 ) and / and the servomotor ( 25 , 33 , 35 ) is combined to form a structural unit. 6. Actuating arrangement according to one of claims 1-5, characterized in that the organ to be actuated is a clutch release ( 27 ). 7. Actuating arrangement according to one of claims 1-5, characterized in that the organ to be actuated is a gear shift shaft ( 43 ). 8. Actuating arrangement according to one of claims 1-7, characterized in that the servomotor ( 25 , 33 , 35 ) is operated at a voltage level which is more than 30 V, for example about 40 V or about 80 V.