JP2024516805A - Method for determining contact points of a torque transmitting device - Patents.com - Google Patents

Abstract

The present invention relates to a method for determining a contact point of a torque transmission device (10), the torque transmission device (10) being configured to transmit a transmission torque that depends on an operating state of an actuating element (20) connected to a hydraulic actuating device (18), the method having a torque transmission characteristic curve (50, 52) that shows a relationship between transmission parameters that at least characterize a maximum transmittable transmission torque and operating parameters of the operating state, characterized in that, starting from a detection time, the contact point is determined by taking as operating parameter a fluid quantity (V) that fills the actuating element (20) and causes a fluid pressure (p) in the actuating element (20), the torque transmission characteristic curve (50, 52) being detected as a function of the fluid quantity (V) and the contact point being calculated as a function of the torque transmission characteristic curve (50, 52).

Description

The present invention relates to a method according to the preamble of claim 1.

The torque transmission device is described, for example, in DE 10 2019 130 158 A1. The torque transmission device is implemented as a dual clutch and has a first clutch and a second clutch, each of which can be actuated by fluid pressure and is hydraulically connected via a respective fluid line to a pump device which supplies the fluid pressure. The actuation control of the respective clutch is carried out by a clutch valve assigned to the respective clutch.

The objective of the present invention is to detect the contact point of a torque transmission device as accurately and easily as possible.

At least one of the problems is solved by a method having all the features of claim 1. Thereby, the contact point of the torque transmission device can be detected more accurately and simply. Environmental influences on the contact point determination can be better adjusted and taken into account. For example, the influence of leakage and temperature during operation of the torque transmission device can be taken into account.

As the contact point of the torque transmission device, in particular the operating state of the actuating device is grasped, in which operating state the torque transmission device, starting from an open state, begins to be able to transmit a transmission torque, for example a transmission torque of 5 Nm.

The torque transmission device may be disposed within a vehicle. The vehicle may be an electric vehicle.

The torque transmission device may be implemented as a clutch. The clutch may transmit the torque of a driving element, for example an internal combustion engine and/or an electric motor, to a driven element, for example a transmission, depending on the operating state of the actuation device. The clutch may be implemented as a first clutch, in addition to which a second clutch may be arranged. The first clutch and the second clutch may be assigned to a dual clutch. The dual clutch may be mounted in front of the load shifting transmission.

The torque transmission device may be implemented as a brake. The transmission torque may be a brake torque of the brake. The brake may support the torque of the driving element and/or the driven element with a fixed reference element depending on the operating state of the actuation device. The reference element may be a housing, in particular a transmission housing.

The detection time may occur when the vehicle is stopped or in operation, particularly when it is moving.

In a preferred embodiment of the invention, it is advantageous if the fluid quantity is delivered by the pumping device and depends on the pump speed of the pumping device. The fluid quantity and the pump speed are mutually temperature-dependent. The higher the temperature of the fluid, the lower the pump speed required for a simultaneously conveyed fluid quantity. The pumping device may have an electrically driven pump. The pump may be a gear pump. The pump may be driven by an electric motor.

In a particular embodiment of the invention, it is advantageous if the operating parameter is detected as a function of the pump speed. The pump speed may be measured. If the pump device is operated by an electric motor, the pump speed depends on the motor speed of the electric motor.

In a particular embodiment of the invention, it is advantageous if the fluid volume delivered by the pump device is only transmitted to the actuating element from the time of detection and during the duration of the contact point determination. Thereby, a transmission parameter can be uniquely assigned to the fluid volume.

In a particular embodiment of the present invention, it is advantageous if the torque transmission device is open at the time of detection. The actuator may be empty based on the fluid volume. If the torque transmission device is open, the transmission of the transmitted torque is interrupted.

In an advantageous embodiment of the invention, it is provided that during the determination of the contact point, the fluid volume is constantly increased starting from the detection time to at least the cut-off point. The fluid flow rate, which increases the fluid volume, can be constantly decreased, preferably already starting from the detection time to the cut-off point, at least in parts, preferably continuously during the determination of the contact point. This allows pressure peaks of the fluid pressure in the actuating element to be reduced. Also, hysteresis effects during pressure increase can be better taken into account.

The amount of fluid increases with the first fluid flow rate starting from the detection time and may decrease with the second fluid flow rate during further changes during the contact point determination. Preferably, the pump speed of the pump device is decreased at least temporarily starting from the detection time or permanently during the entire duration of the contact point determination.

In a preferred embodiment of the invention, the cut-off point corresponds to the amount of fluid delivered, at which the fluid pressure advantageously assumes a first pressure value. The cut-off point may have a deviation before the contact point, in particular based on the amount of fluid delivered, so that overshoots of the fluid pressure can be reduced. The deviation may be temperature-dependent and/or may be determined in advance. The deviation may be determined by the aforementioned measurements.

In a preferred embodiment of the present invention, it is advantageous if the fluid pressure applied to the actuating element is employed as the transmission parameter. The transmitted torque can also be employed as the transmission parameter. For example, the transmitted torque can be detected at the torque transmission device when the torque is being applied.

In a particular embodiment of the invention, the contact point is a contact point position on the torque transmission characteristic curve, which is advantageous if it is in the transition between a first characteristic curve portion having at least one first slope and a second characteristic curve portion having at least one second slope that is greater than the first slope. The first characteristic curve portion may have a constant first slope. The second characteristic curve portion may have a constant second slope. The first characteristic curve portion and/or the second characteristic curve portion may also have a non-linear course. At least one of the two characteristic curve portions may be characterized as being linear. The contact point position may be a crossover position between a linear or non-linear course characterizing the first characteristic curve portion and a linear course characterizing the second characteristic curve portion. The linear course of the first characteristic curve portion may have a first slope. The linear course of the second characteristic curve portion may have a second slope.

In a particular embodiment of the invention, it is contemplated that the torque transmission characteristic curve is formed by measurement data points, the first characteristic curve portion being a first regression of the measurement data points assigned to the first characteristic curve portion, and the second characteristic curve portion being a second regression of the measurement data points assigned to the second characteristic curve portion. The regression may be performed with the aim of reducing the squared error between the measurement data points and the approximated course associated with the measurement data points.

Further advantages and advantageous embodiments of the present invention will become apparent from the description and drawings.

The present invention is described in detail below with reference to the drawings.

FIG. 2 is a diagram of a hydraulic actuator for actuating a torque transmission device according to a specific embodiment of the present invention. 4 is a torque transmission characteristic curve of a torque transmission device according to a specific embodiment of the present invention.

Figure 1 shows a hydraulic actuator 18 for operating a torque transmission device 10 of a specific embodiment of the present invention. The torque transmission device 10 includes a first clutch 12 and a second clutch 14, each of which can transmit a transmission torque. The transmission torque can be a driving torque of a driving element, for example, an internal combustion engine and/or an electric motor, and can be transmitted via the torque transmission device 10 to a driven element, for example, a transmission, preferably a load-shifting transmission.

The first clutch 12 and the second clutch 14 are preferably assigned to a dual clutch 16, and the transmission is preferably a dual clutch transmission. The transmission can have at least two transmission stages. In the case of an electric motor as the drive element, this also makes it possible to achieve an increase in the drive efficiency through a large driven speed range of the transmission.

The torque transmission device 10 is connected to an actuating device 18, which has a first actuating element 20 for actuating the first clutch 12 and a second actuating element 22 for actuating the second clutch 14. The transferable torque through the first clutch 12 depends on the actuation state of the first actuating element 20. The transferable torque through the second clutch 14 depends on the actuation state of the second actuating element 22. The first actuating element 20 and the second actuating element 22 are actuable independently of each other and are assigned to a hydraulic actuating device 18, which supplies a fluid pressure and a fluid flow rate by a pump device 24.

The pump device 24 is connected to the fluid reservoir 26 via a fluid filter 28 and to a first clutch branch 32 hydraulically connected to the first actuating element 20 via a system pressure branch 30 and to a second clutch branch 34 hydraulically connected to the second actuating element 22. The operating state of the first clutch 12 depends on the fluid pressure in the first clutch branch 32 and the operating state of the second clutch 14 depends on the fluid pressure in the second clutch branch 34.

The system pressure branch 30 is connected to the first clutch branch 32 via a first check valve 36 and a first clutch valve 38, and to the second clutch branch 34 via a second check valve 40 and a second clutch valve 42. The system pressure valve 44 allows control of the system pressure by a return connection of the system pressure branch 30 to the fluid reservoir 26.

The pump device 24 is actuated by an electric motor 46 and is preferably connected to the electric motor 46 in such a way that it cannot rotate relative to it. The rotational speed of the electric motor 46 is then linked to the rotational speed of the pump device 24. If the rotational speed of the electric motor 46 is known, then the rotational speed of the pump device 24 is also known. By actuating the pump device 24, the system pressure increases, and by controlling the first clutch valve 38, the fluid pressure in the first clutch branch 32 and thus also at the first actuating element 20 increases, so that the first clutch 12 for transmitting the transmission torque can be actuated. By controlling the second clutch valve 42, the fluid pressure in the second clutch branch 34 and thus at the second actuating element 22 increases, so that the second clutch 14 for transmitting the transmission torque can be actuated.

In order to be able to transmit the transmission torque through the first clutch 12 as accurately and economically as possible, knowledge of the contact point of the first clutch 12 is necessary. The contact point is defined by means of a torque transmission characteristic curve of the first clutch 12, which shows the relationship between a transmission parameter that characterizes at least the maximum transmittable transmission torque through the first clutch and an operating parameter of the operating state. The transmission parameter can be the fluid pressure in the first clutch branch 32 or the transmission torque of the first clutch 12. The torque transmission characteristic curve is determined by a number of measured data points, and then the contact point is calculated by regression from the torque transmission characteristic curve.

The method for determining the contact point of the first clutch 12 starts, for example, from a detection time point at which the first clutch 12 is open and the torque transmission through the first clutch 12 is interrupted. The system pressure valve 44 is closed or remains closed, and the second clutch valve 42 is closed or remains closed. As a result, the fluid pressure supplied from the pump device 24 is directed only to the first clutch branch 32.

As an operating parameter, the fluid volume that fills the first operating element 20 and causes the fluid pressure of the pump device 24 therein is adopted. At the time of detection, the first clutch branch is preferably empty and the pump device 24 starts to convey the fluid volume into the system pressure branch 30 and to the first clutch branch 32 by the closed system pressure valve 44 and the closed second clutch valve 42. The fluid pressure measured by the pressure sensor 48 in the first clutch branch 32 and the assigned fluid volume are recorded as measured measurement data points and are used for the regression of the torque transmission characteristic curve.

The amount of fluid that is constantly increased in the system pressure branch 30 and thus in the first clutch branch 32 depends on the time point when the pump speed of the pump device 24 and the motor speed of the electric motor 46 are detected. The amount of fluid is preferably detected by the pump speed or the motor speed and increases, for example, up to a cut-off point corresponding to the amount of fluid conveyed, at which the fluid pressure in the first actuating element 20 has assumed or exceeded the first pressure value.

Starting from the detection time, the fluid quantity is increased by two possible procedures. In a first procedure, the first clutch branch 32 is filled with a very high fluid flow rate until the fluid pressure reaches or exceeds a first pressure value. In a second procedure, the first clutch branch 32 is filled with a very high fluid flow rate and, at the beginning of the pressure action of the first clutch 12, with an increasing fluid pressure by reducing the fluid flow rate. The second procedure lasts longer than the first procedure, but the dynamic pressure in the first clutch branch and therefore the pressure peaks are reduced, improving the accuracy of the contact point determination. Also, the influence of moments and pressure hysteresis in the system is reduced by the slow movement of the first actuating element 20.

2 shows the torque transmission characteristic curves of a torque transmission device according to a specific embodiment of the invention. In FIG. 2, the torque transmission characteristic curve 50 of a torque transmission device implemented as a clutch, for example as a first clutch, and the further torque transmission characteristic curve 52 of a torque transmission device implemented as a brake are shown in comparison. For both torque transmission characteristic curves 50, 52, the fluid pressure p in the actuating element and the fluid volume V of the pump device delivered to the actuating element are used as the transmission parameter.

Based on the torque transmission characteristic curve 50 of the clutch, a contact point is calculated from the torque transmission characteristic curve 50 as a contact point position 54, which is in the transition between a first characteristic curve portion 56 having at least one first slope and a second characteristic curve portion 58 having at least one second slope greater than the first slope. Via the measurement data points 60, the first characteristic curve portion 56 is illustrated by a first regression of the measurement data points 60 assigned thereto, and the second characteristic curve portion 58 is illustrated by a second regression of the measurement data points 60 assigned thereto.

The first characteristic curve portion 56 is formed by linear regression and has a constant first slope. Similarly, the second characteristic curve portion 58 is formed by linear regression and has a constant second slope that is greater than the first slope. Preferably, the density of the measurement data points 60 increases with an increase in the fluid volume V, for example by detecting the fluid volume V and the fluid pressure p at constant, defined time intervals and constantly lowering the pump speed starting from the detection time. Overshoots in the system can thereby also be reduced. The duration of the operating time of the pump device for increasing the fluid volume V during the detection of the contact point preferably depends on the contact point. The cut-off point 62 from which the pump device 24 stops is preferably located before the contact point by a deviation 64 based on the delivered fluid volume V. The deviation 64 can also be selected depending on environmental parameters, for example temperature. These dependencies can be determined by a series of experiments.

10 Torque transmission device 12 First clutch 14 Second clutch 16 Dual clutch 18 Actuating device 20 First actuating element 22 Second actuating element 24 Pump device 26 Fluid storage 28 Fluid filter 30 System pressure branch 32 First clutch branch 34 Second clutch branch 36 First check valve 38 First clutch valve 40 Second check valve 42 Second clutch valve 44 System pressure valve 46 Electric motor 48 Pressure sensor 50 Torque transmission characteristic curve 52 Torque transmission characteristic curve 54 Contact point position 56 First characteristic curve portion 58 Second characteristic curve portion 60 Measurement data point 62 Cut-off point 64 Deviation

Claims (10)

A method for determining a contact point of a torque transmission device (10), the torque transmission device (10) being configured to transmit a transmission torque that depends on an operating state of an actuating element (20) connected to a hydraulic actuating device (18), the torque transmission device (10) having a torque transmission characteristic curve (50, 52) showing a relationship between transmission parameters that characterize at least a maximum transmittable transmitted torque and operating parameters of the operating state, the method comprising:
CHARACTERIZED IN THAT, STARTING FROM A DETECTION TIME, THE TOUCH POINT IS DETERMINED BY TAKING AS AN ACTIVATION PARAMETER A VOLTAGE (V) FULLING THE ACTIVATION ELEMENT (20) AND CAUSING A HYDRAULIC PRESSURE (P) THEREIN, THE TOUCH TRANSMISSION CHARACTERISTICS CURVE (50, 52) DETECTED AS A FUNCTION OF THE VOLTAGE (V) AND THE TOUCH POINT IS CALCULATED AS A FUNCTION OF THE HYDRAULIC PRESSURE (V). The method according to claim 1, characterized in that the fluid volume (V) is supplied by a pump device (24) and depends on the pump speed of the pump device (24). The method according to claim 2, characterized in that the operating parameter is detected according to the pump rotation speed. The method according to any one of claims 1 to 3, characterized in that from the detection time and during the duration of the contact point determination, the volume of fluid (V) delivered from the pump device (24) is transmitted only to the actuating element (20). The method according to any one of claims 1 to 4, characterized in that the torque transmission device (10) is open at the time of detection. The method according to any one of claims 1 to 5, characterized in that during the determination of the contact point, the fluid volume (V) is constantly increased starting from the detection time up to at least a cut-off point (62). The method of claim 6, characterized in that the cut-off point (62) corresponds to a volume of fluid conveyed at which the fluid pressure (p) assumes a first pressure value. The method according to any one of claims 1 to 7, characterized in that the fluid pressure (p) applied to the actuating element (20) is adopted as a transmission parameter. The method according to any one of claims 1 to 8, characterized in that the contact point is a contact point position (54) on the torque transmission characteristic curve (50, 52), the contact point position (54) being in a transition between a first characteristic curve portion (56) having at least one first slope and a second characteristic curve portion (58) having at least one second slope greater than the first slope. The method according to claim 9, characterized in that the torque transmission characteristic curve (50, 52) is formed by measurement data points (60), the first characteristic curve portion (56) is a first regression of the measurement data points (60) assigned to the first characteristic curve portion (56), and the second characteristic curve portion (58) is a second regression of the measurement data points (60) assigned to the second characteristic curve portion (58).

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