WO2004065825A1 - Control system for a gear selector drum of an automatic gear transmission of a motor vehicle - Google Patents

Abstract

During gear shift from an initial gear to a target gear the rapid synchronization of the transmission input shaft to the synchronous speed of the target gear may result in unpleasantly perceptible synchronization knocks. The aim of the invention is therefore to provide a control system which allows for fast yet comfortable gear shifts. The inventive control system is provided with a position control which controls a modulator, thereby bringing the gear selector drum into the position required for engaging the target gear. The required control behavior is not constant over the entire course of gear shifting. According to the invention, control parameters of the position control depend on a deviation of the actual position from a desired position of the gear selector drum, thereby making it possible to adapt the control behavior to the respective requirements.

Description

 Control system for a shift drum of a gear change transmission of a motor vehicle

The invention relates to a control system for a shift drum of a gear change transmission of a motor vehicle according to claim 1.

Shift drums for actuating shifting elements, for example sliding sleeves, of gear change transmissions are generally known. A shift drum has control cams in which so-called shift pins engage. The switching pins are operatively connected with sliding sleeves. When the shift drum is rotated, one or more sliding sleeves are actuated depending on the position of the shift drum, thus engaging or disengaging one gear of the gear change transmission. To engage a gear, a specific position of the shift drum must be set.

DE 28 08 894 AI describes a gear change transmission with a shift drum, in which gears are sequentially engaged and disengaged by rotating the shift drum. EP 0 741 258 B1 describes a gear change transmission with a shift drum, in which the positive coupling between shift drum and shift pin can be canceled. This means that when the shift drum rotates, the engagement and disengagement of individual gears can be skipped; sequential shifting of the gears is no longer necessary.

The invention has for its object to provide a control system for a shift drum, which is comfortable and enables rapid gear changes of the gear change transmission. According to the invention the object is achieved by a control system having the features of claim 1.

The control system according to the invention has an actuator for changing the position of the shift drum and a position controller which regulates the position of the shift drum when changing from an original gear to a target gear. The control system controls the actuator for this purpose. To engage the target gear, the shift drum must be set to a specific target or target position. The position controller has the position of the shift drum as the control variable and the control signal for the actuator as the manipulated variable and thus indirectly the rate of change of the position, that is to say the rotational speed, of the shift drum. The setpoint corresponds to the target. or target position of the shift drum in the target gear. The position of the shift drum is thus given as an angular position relative to a neutral position.

According to the invention, controller parameters of the position controller are dependent on a deviation of an actual position from the target position of the shift drum, that is to say on the control deviation of the position controller. The position controller is thus designed as a so-called adaptive controller. The position controller can be composed of various components, such as a proportional component (P component) and / or a differential component (D component) and / or an integral component (I component) and / or a constant component. The controller parameters determine the behavior of the position controller. Controller parameters are, for example, a gain or proportional factor of the proportional component, the level of the constant component or parameters of the D or I component. One or more components can also be deactivated, so that the component or components no longer have any influence on the controller behavior. The actuator can be designed, for example, as an electric motor or a hydraulic or pneumatic piston-cylinder unit. The term original gear is also understood to mean a neutral position of the gear change transmission, that is to say a position without a gear engaged.

A gear change from an origin to a target gear consists of several phases. An exemplary phase curve during a gear change is shown below. Depending on the phases, the position of the shift drum changes or remains constant. In a first phase, the torque delivered by a drive machine is reduced. At the same time, a clutch arranged between the drive machine and the gear change transmission can be opened at least partially; the position of the shift drum remains unchanged. In a second phase, the original route is laid out. This is achieved by rotating the shift drum. In a third phase, a transmission input shaft is synchronized to a synchronous speed in the target gear. In a so-called synchronized gear change transmission, this is done with a synchronizing device, for example synchronizing rings, which is each assigned to a gear. During the synchronization, a force is exerted on the synchronizing device by the shift drum without the position of the shift drum changing or with a change in position with the interposition of spring elements in the force flow. After synchronization, in a fourth phase the target gear is engaged by a further change in the position of the shift drum in the target or target position. Finally, the output torque of the drive machine is built up again and the clutch, if it was opened previously, closed again. The position of the shift drum remains unchanged. The phases mentioned above may overlap. According to the invention, the controller behavior required for fast and comfortable shifting is not constant in the phases of the gear change mentioned and in the transitions between the phases. It changes depending on the controller deviation. By adapting the controller parameters depending on the controller deviation, the controller behavior can be changed according to the requirements in the individual phases and the phase transitions.

A comparable behavior of the control device can also be achieved by controlling the control signal for the actuator. The control would depend on the angle of rotation of the shift drum in this case. This can be determined based on the position in the source corridor. Alternatively, the twist angle still required to engage the target gear can be used. This corresponds to the described deviation of the actual position from the target position of the shift drum when using a position controller.

One requirement for a gear change transmission is to carry out fast gear changes. One reason for this is that a power flow between the drive machine and the driven vehicle wheels is possible again very quickly. In order to be able to achieve this, the position of the shift drum must be changed very quickly, i.e. rotated very quickly. If the speed of rotation is too high, a so-called, uncomfortably noticeable synchro beat can occur. A synchronous beat occurs when the synchronization is started too quickly, the force on the synchronizing device is too great and the synchronization process is therefore carried out too quickly. In other phases of gear change, however, a higher twisting speed can be possible without sacrificing comfort. With the control system according to the invention, the rotational speed can be adapted to the requirements of the individual phases. For example, this can be done and / or be reduced during the synchronization process in that the position controller controls the actuator with a control signal which is smaller than the maximum control signal.

In other phases, a higher, in particular maximum, rotational speed can be set. For this purpose, the actuator is controlled with a maximum control signal in terms of amount. This can be done without negatively impacting comfort, especially when disengaging the original gear and / or after synchronizing the transmission input shaft, making comfortable and fast gear changes possible.

In an embodiment of the invention, the position controller has a proportional and a constant component. A proportional factor of the proportional component and / or the constant component is dependent on a deviation of an actual position from the target position of the shift drum, that is to say on the control deviation of the position controller. The proportional and / or constant portion can also be zero.

In an embodiment of the invention, the deviation is divided into different sections. The deviation can be negative or positive, depending on whether an upshift or a downshift is carried out. The proportional factor and the constant component are constant within these sections. The sections can at least partially correspond to the phases mentioned during the gear change and transitions between the phases. A simple construction of the controller is thus achieved. This means that the controller can also be tuned particularly quickly in the form of a determination of the controller parameters.

In an embodiment of the invention, the proportional factor is zero in selected sections of the deviation mentioned. This allows a constant in the selected sections Control signal for the actuator are generated. This is particularly advantageous in a first section in which the original gear is designed and / or in a third section in which the synchronization of the transmission input shaft takes place and / or in a fourth section in which engagement of the target gear begins. In the first and fourth sections, the shift drum can be rotated at maximum speed, without this having a negative impact on the comfort of changing gears. This results in particularly fast and at the same time comfortable gear changes if the constant component in these sections corresponds to the maximum control signal in terms of amount, that is to say the position of the shift drum is changed at maximum speed.

In the third section, i.e. during the synchronization, a control signal can be set which allows synchronization without a synchro beat, but which is nevertheless carried out as quickly as possible.

In an embodiment of the invention, the third section begins with a larger deviation compared to a deviation at the start of the synchronization. This means that the speed of the change in the position of the shift drum is limited to the permitted level before the start of synchronization. This reliably avoids a synchro beat. The exact position of the shift drum at the start of synchronization does not have to be known, since a safety distance is maintained. A change in position at the start of the synchronization, for example due to component tolerances or wear, can also be compensated with the safety distance. An extension of the switching time is hardly noticeable.

In an embodiment of the invention, in a fifth section, which follows the fourth section in the direction of a small deviation, and in a sixth section, which follows the fifth section in the same direction, the proportional factor has a non-zero constant value. The amount of the proportionality factor in the sixth section is smaller than the proportionality factor in the fifth section. In a seventh section, which ends with a deviation from zero, the proportional factor and the constant component are zero. In the seventh section, the controller is insensitive to so-called measurement noise when determining the actual position of the shift drum. With such a controller, a stable and steadily accurate control is made possible.

In an embodiment of the invention, the limits of the sections mentioned can be changed. The limits can thus be adapted. The position of the shift drum at the beginning and end of the phases of the gear change mentioned can be determined on the basis of observation of operating variables of the motor vehicle or of the actuator, for example the measured position of the shift drum, the rotational speeds of the gear change transmission or the current through the actuator. The start of the synchronization can be recognized, for example, by a sudden increase in the current strength of the control current for the actuator. By comparing the determined positions with the saved limits of the sections, the limits can be adapted to the actual circumstances.

In an embodiment of the invention, the limits of the sections mentioned and / or the proportionality factors and / or the constant portions depend on the actual and target gear. The optimal controller behavior is not identical for all possible gear changes. This is due, for example, to different geometries or different wear in the different gears. Due to the dependencies mentioned, the controller behavior can be optimally designed for every gear change. As an alternative or in addition to the above-mentioned dependencies, the limits of the above-mentioned sections and / or the proportionality factors and / or the constant components can depend on further state, operating or environmental variables of the motor vehicle.

Further embodiments of the invention are evident from the description and the drawing. Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. The drawing shows:

1 shows a section of a gear change transmission with a shift drum and a control system for the shift drum and

Fig. 2 is a characteristic curve of a position controller

Control system of the shift drum.

Fig. 1 shows a section of a schematically illustrated gear change transmission with a switching device

10 for actuating switching elements for inserting and disengaging the various gears of the gear change transmission. The gear change transmission has several shift elements, only one shift element in the form of a sliding sleeve

11 and is mentioned below as a representative.

The switching device 10 has a switching drum 13 which can be rotated about an axis of rotation 12 and which is driven by an actuator in the form of an electric motor 14. On an output shaft 15 of the electric motor 14, a gear 16 is attached, which meshes with an external toothing 17 molded onto the shift drum 13.

The shift drum 13 has a control cam 18 in which a shift pin 19 engages. The shift pin 19 is connected to a shift fork 21 via a coupling element 20. The shift fork 21 partially encloses the sliding sleeve 11. With a rotation of the shift drum 13, the sliding sleeve 11 can be moved parallel to the axis of rotation 12 of the shift drum 13 in accordance with the course of the control cam 18. By shifting the sliding sleeve 11, a gear in the gear change transmission can be engaged or disengaged in a known manner. The shift drum 13 has a corresponding cam, not shown, for each additional shift element. Each gear of the gear change transmission can thus be engaged or disengaged by rotating the shift drum 13. With the illustrated switching device 10, the gears can be sequentially engaged and disengaged. The switching device can also be designed so that the engagement and disengagement of individual gears can be skipped. This can be achieved, for example, with a shift drum described in EP 0 741 258 B1.

The electric motor 14 is controlled by a control device 22. The control device 22 is in addition to the electric motor 14 with a position sensor 23 and an operating lever 24 in signal connection. The current actual position of the shift drum 13 can be detected by means of the position sensor. Shifts from an original gear into a target gear can be determined by a vehicle driver using the control lever 24 or in a manner known per se by the control device 22 as a function of operating variables of the motor vehicle, such as vehicle speed and position of an accelerator pedal.

The control device 22 contains a position controller which sets the shift drum 13 to the current desired position. For this purpose, the control device 22 changes the polarity and / or the level of the voltage applied to the electric motor 14. By changing the polarity, the direction of rotation and by changing the amount of voltage, the speed of rotation or the torque that can be applied to the electric motor 14 can be changed. The control signal is determined by the position controller from the actual position and the target position of the shift drum 13 according to a characteristic curve.

When a shift from an origin to a target gear is triggered, the control device 22 predefines a new desired position of the shift drum 13. The position controller thus calculates corresponding control signals for the electric motor 14, so that the shift drum 13 is brought into the desired position.

The characteristic curve 32 of the position controller is shown in FIG. 2. The deviation of the actual position from the target position of the shift drum 13 is on an abscissa 30; The ordinate 31 plots the level of the control signal for the electric motor 14 in the form of the applied voltage. The characteristic curve is only shown for positive deviations. For negative deviations, the characteristic curve results from a mirroring of the characteristic curve 32 shown on the ordinate 31. Asymmetrical characteristic curves are also possible. When changing gear, the characteristic curve 32 is traversed by large deviations in the direction of small deviations.

The characteristic curve 32 has a proportional component and a constant component. The proportional component causes an increase in the characteristic curve 32, the size of which corresponds to the proportional factor of the proportional component. The constant component causes the characteristic curve 32 to be displaced along the abscissa 31. The proportional factor and the constant component change as a function of the deviation of the actual position from the target position, the sizes being constant in sections.

The gear change begins with a deviation 33, which corresponds to the angle of rotation between the position of the shift drum 13 in the original gear and the target position in the target gear. At the beginning of the gear change, the torque output of a drive machine, not shown, is reduced and a clutch, also not shown, between the drive machine and gear change transmission is opened. The shift drum 13 is then rotated in the direction of the desired position, so that the deviation decreases. There is no more torque on the sliding sleeve of the original gear, so that in a first section a the original gear is designed by moving the sliding sleeve. The design can take place at the maximum rotational speed, so that the voltage corresponds to a maximum value 34. The proportional factor and thus the proportional component is zero in section a, the constant component corresponds to the maximum value 34.

In the event of a deviation 35, the synchronization of the target gear begins to take effect. When this deviation 35 is reached, the speed of rotation of the shift drum 13 must not be too high, since otherwise a noticeable synchronous beat would occur. For this reason, in a second section b, which follows section a in the direction of smaller deviations, the proportionality factor and the constant component are selected such that in the event of a deviation 36, which is larger by a safety margin than the deviation 35, in which the synchronization begins to act, a voltage 37 is reached at which no synchronous beat occurs. In section b, the characteristic curve 32 connects the maximum value 34 of the voltage with the voltage 37.

In the subsequent third section c, the voltage 37 remains constant. The proportionality factor is again zero. The shift drum 13 is first rotated until the deviation 35, at which it then remains until the synchronization is complete. The shift drum 13 can then be rotated further and the synchronization switched through. In the case of the deviation 38, the synchronization is safely completed, so that the voltage is set to the maximum value 34 again in the fourth section d beginning with the deviation 38. The shift drum is rotated at maximum speed and the target gear is engaged at maximum speed. The speed must be reduced in good time before the target position is reached, otherwise there would be a strong overshoot.

For this reason, section d is followed by a fifth section e with a proportionality factor greater than zero. The voltage drops with a falling deviation. The constant component in the factor e is chosen such that the characteristic curve 32 is continuous. In the event of a deviation 39, a sixth section f begins, the characteristic curve becoming flatter and the proportionality factor smaller.

In the event of a deviation 40, the target position is virtually reached. For this reason, in a seventh section g that begins with this, the proportionality factor and the constant component become zero, which results in a voltage of zero. The shift drum is therefore no longer rotated. The switching device 10 is designed such that the target gear is securely engaged when the position of the shift drum 13 is within a tolerance range around the desired position. The tolerance range is limited in the positive direction by the deviation 40. The controller behavior in sections d to g allows the position of the shift drum 13 to be controlled stably and precisely.

As soon as the target gear is engaged, the clutch is closed again and the torque of the drive machine requested by the driver is set. The gear change is now complete. In addition to the sections shown, the characteristic curve can also have further sections.

The control system described can also be used for other switching devices, for example with switching rods known per se. These can be rotated and / or shifted so that the position can correspond to an angular position as well as a displacement distance from a neutral position.

Claims

claims 1. Control system for a shift drum (13) of a gear change transmission of a motor vehicle, gears of the gear change transmission being able to be engaged and disengaged by means of a change in position of the shift drum (13) - An actuator (electric motor 14) for changing the position of the shift drum (13) and - A position controller, which controls the position of the shift drum (13) when changing from an original gear to a target gear and that Actuating actuator (electric motor 14), wherein controller parameters of the position controller are dependent on a deviation of an actual position from a target position of the shift drum (13). 2. Control system according to claim 1, so that the position controller controls the actuator (electric motor 14) in selected areas with a maximum control signal (34). 3. Control system according to claim 2, d a d u r c h g e k e n n z e i c h n e t that - when laying out the original duct (section a) and / or - After synchronization of a transmission input shaft (section d) the position controller the actuator (electric motor 14) with the maximum control signal (34). 4. Control system according to claim 1, 2 or 3, so that the position controller controls the actuator (electric motor 14) with a control signal (37) which is smaller than the maximum control signal (34) before the synchronization of the transmission input shaft begins. 5. Control system according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the position controller - a proportional component and - has a constant portion and - a proportional factor of the proportional component and / or - The constant portion of a deviation of an actual position from a target position of the shift drum (13) are dependent. 6. Control system according to claim 5, characterized in that the deviation is divided into different sections (a, b, c, d, e, f, g) and the proportional factor and / or the constant portion in the sections (a, b, c, d, e, f, g) are constant. 7. Control system according to claim 6, characterized in that the proportional factor in selected sections of said deviation is zero. 8. Control system according to claim 7, d a d u r c h g e k e n n z e i c h n e t that - In a first section (a), in which the original passage is laid out and / or - In a third section (c), in which a synchronization of the transmission input shaft takes place and / or - In a fourth section (d), in which the target gear begins to be engaged, the proportional factor is zero. 9. Control system according to claim 8, d a d u r c h g e k e n n z e i c h n e t that in the first section (a) and / or fourth section (d), the constant portion corresponds to the maximum control signal (34) of the position controller. 10. Control system according to claim 8 or 9, so that the third section (c) begins with a larger deviation (36) compared to a deviation (35) at the start of the synchronization. 11. Control system according to claim 8, 9 or 10, d a d u r c h g e k e n n z e i c h n e t that - In a second section (b), which is arranged between the first (a) and third section (c), and / or - In a fifth section (e), which on the fourth section (d) in the direction of small deviation follows, the proportional factor corresponds to a constant non-zero value. 12. Control system according to one of claims 8 to 11, characterized in that the deviation has a sixth section (f) which follows the fifth section (e) in the direction of small deviation and in which the proportional factor is constant and smaller in magnitude than the proportional factor in the fifth Section (e) is. 13. Control system according to one of claims 6 to 12, so that in a seventh section (g), which ends with a deviation from zero, the proportional factor and the constant component are zero. 14. Control system according to one of claims 6 to 13, that the limits of the said sections (a, b, c, d, e, f, g) can be changed. 15. Control system according to one of claims 1 to 14, d a d u r c h g e k e n n z e i c h n e t that - the controller parameters of the position controller and / or, - the proportionality factors and / or - The constant parts and / or - The limits of the mentioned sections (a, b, c, d, e, f, g) depend on the actual and target gear.