WO2021213580A1

WO2021213580A1 - Method and fluid system for the actuation of a transmission component and a disconnecting device

Info

Publication number: WO2021213580A1
Application number: PCT/DE2021/100289
Authority: WO
Inventors: Marco Grethel; Ivo Agner; Carsten Mayer; Reinhard Stehr
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2020-04-21
Filing date: 2021-03-23
Publication date: 2021-10-28

Abstract

The invention relates to a method for the actuation of a transmission component (15) and a disconnecting device (16) in a drive train (10) with the aid of a fluid system which comprises a supply pressure region, in which a supply pressure is provided by way of a fluid pump which is driven by electric motor, a transmission pressure region which is assigned to the transmission component (15), and a disconnecting pressure region which is assigned to the disconnecting device (16). In order to prevent damage or malfunctions of the transmission component, a transmission of torque via the transmission component (15) is limited in an emergency by way of opening of the disconnecting device (16) or by way of a motor operation on a drive unit (70) in the drive train (10).

Description

Method and fluid system for actuating a transmission component and a separating device

The invention relates to a method for actuating a transmission gear component and a separating device according to the preamble of claim 1. The invention also relates to a fluid system for actuating a transmission gear component and a separating device according to the preamble of claim 5.

From the German patent application DE 102018 104093 A1 a fluid system for a continuously variable belt transmission is known, with an electric motor driven first pump and an electric motor driven second Pum pe, wherein a first connection of the first pump is connected to a line section leading to a reservoir and a second connection of the first pump is fluidically connected to a first actuating device assigned to a first set of pulleys of the belt drive and to a first connection of the second pump, and a second connection of the second pump is assigned to a second set of disks of the belt drive , second actuating device is fluidically connected, the first pump being fluidically connected to a pressure accumulator on the part of its first connection.

The object of the invention is to prevent component damage and / or failure of the transmission gear in a drive train.

The task is in a method for actuating a transmission gear component and a separation device in a drive train with the aid of a fluid system that has a supply pressure area in which a supply pressure is provided by an electric motor-driven fluid pump, a transmission pressure range assigned to the transmission gear component and one of the separation Device associated separating pressure range comprises, achieved in that in an emergency a torque transmission via the transmission gear component is limited by opening the separating device or by engine intervention on a drive unit in the drive train. With the transmission gear component, a translation in the drive train can advantageously be changed without a positive fit. The transmission gear component is preferably part of a continuously variable transmission gear. The continuously variable transmission can be designed with or without a belt. If the transmission gear is equipped with a belt, then it is, for example, a variator of a continuously adjustable conical disk benumschlingungsgetriebes. If the transmission gear component is guided without looping, then it is, for example, a frictional transmission gear, such as a friction gear. In an emergency, the main task is to make the transmission gear components in the drive train free of torque. A torque reduction required for this purpose can, for example, take place through an engine intervention in the drive unit, in particular through an engine intervention in an internal combustion engine. Alternatively or additionally, the separating device, which is preferably designed as a coupling, can be opened. The claimed OR variant provides a redundant emergency path for an inherently undesirable emergency.

A preferred exemplary embodiment of the method is characterized in that the pressure in the transmission pressure range is compared with the supply pressure in the supply pressure range in order to identify an emergency situation and initiate emergency measures. The pressure in the transmission pressure area and / or the pressure in the supply pressure area can be recorded, for example, with a pressure sensor device. The pressure or a corresponding pressure difference can, however, also be recorded differently, for example via at least one differential pressure valve. Depending on the design of the fluid system, an existing pressure sensor can be used to detect a noticeable drop in supply pressure. If the supply pressure drop falls below a predefinable lower supply pressure limit, then this can be assessed as an emergency situation in which appropriate emergency measures are then initiated.

Another preferred embodiment of the method is characterized in that the transmission pressure range in the event of a significant pressure drop in the supply pressure in the fluid system is separated from the supply pressure area as part of a first emergency measure. In this way, an existing pressure level in the transmission pressure range can be kept as long as possible. Damage to the transmission gear component can thereby advantageously be prevented. As part of a second emergency measure, the pressure in the separating pressure area is advantageously reduced at the same time, so that a torque which can be transmitted in the drive train at the separating device is reduced more quickly than a corresponding transmittable torque at the transmission gear component. As part of the second emergency measure, for example, the disconnecting device designed as a coupling is opened. The second emergency measure can be initiated actively or passively.

Another preferred exemplary embodiment of the method is characterized in that the pressure is included in the transmission pressure range. In an emergency, the operation of the transmission gear component in the drive train is advantageously maintained for as long as possible. In the case of a variator of a continuously variable transmission, this means in particular that both pressure and adjustment of the variator are frozen.

In a fluid system for actuating a transmission component described above and a separating device in a drive train, with at least one electric motor-driven fluid pump that provides a supply pressure in the fluid system, and with a transmission pressure valve device, the above-mentioned object is alternatively or additionally achieved by an emergency shut-off valve device , which serves to passively slow down an emergency fluid pressure reduction in a transmission pressure range. As a result, the pressure in the transmission pressure range can be maintained as long as possible, so that damage to a transmission component is avoided.

A preferred exemplary embodiment of the fluid system is characterized in that the emergency shut-off valve device comprises at least one differential pressure valve, via which the transmission pressure area is passively separated from the supply pressure area. With the at least one differential pressure valve, the previously described First emergency measure to protect the transmission gear components can be implemented cost-effectively.

Another preferred exemplary embodiment of the fluid system is characterized in that an emergency opening valve device comprises at least one differential pressure valve, via which the separating pressure area is passively relaxed. With this differential pressure valve, the second emergency measure described above can also be implemented inexpensively.

Another preferred embodiment of the fluid system is characterized in that the first-mentioned and / or the second-mentioned differential pressure valve is / is equipped with position detection in order to trigger an active pressure reduction in the separating pressure range and / or a drive intervention in an emergency. This further increases the safety in the operation of the fluid system, in particular in an emergency situation.

Another preferred exemplary embodiment of the fluid system is characterized in that a pressure return from the transmission pressure range taps off a control pressure upstream or downstream of the transmission pressure valve device. This makes it relatively easy to ensure that the first emergency measure is automatically initiated in an emergency situation.

Another preferred embodiment of the fluid system is characterized in that the transmission pressure valve device comprises two transmission pressure valves, to which an OR valve is assigned, via which only the higher of two transmission pressures in the transmission pressure range is returned. The exemplary embodiment with the OR valve is advantageous, for example, in a variator in which the pressure in the transmission pressure range is used both for adjusting and for pressing the variator.

The method described above and the fluid system described above can advantageously be used in different transmission applications. In the following, preferred embodiments of a transmission application are described in which the transmission ratio component is a variator. The variator belongs to a continuously variable belt drive that includes two sets of pulleys. The pulley sets each include, for example, two bevel gears that are connected to one another for torque transmission by means of a belt such as a push link belt or a chain. Transmissions with continuously variable ratios are also known as CVT transmissions, with the capital letters CVT standing for the English term continuously variable transmission. On the one hand, the fluid system serves to maintain the required pressure in the pulley sets in order to be able to transmit the torque required in each case via the variator, i.e. via the pulley sets and the belt. If the fluid pressure in the fluid system is only provided with the fluid pump driven by an electric motor, then the fluid pump will no longer work if the electrical supply fails. Suitable measures are therefore provided which, in the event of an undesirable failure of the electrically driven fluid pump, prevent damage or even failure of the variator. If the electrically driven fluid pump fails, it is ensured that the torque to be transmitted in the variator is reduced faster than the transmitted torque due to a drop in contact pressure of at least one or both disk sets. The drive train is preferably not a purely electric drive train. The drive train includes, for example, an internal combustion engine and an electric machine as a drive. In addition to the variator, a separating device is provided between the drive and an output. The separating device is, for example, a separating clutch that is designed as a friction clutch. The separating clutch can be arranged in the drive train in front of or behind the variator. With the emergency shut-off valve device that is claimed, in the event of a fault, i.e. if the electrical supply fails, the torque that can be transmitted in the drive train is reduced faster than the corresponding torque that can be transmitted via the variator. The emergency measures serve to passively slow ver the emergency fluid pressure reduction on the disk sets of the variator. Passive means that no valve force has to be applied directly via a valve current supply or indirectly via a pivot valve to close the emergency shut-off valve device. The emergency closing valve device can comprise at least one emergency closing valve. The emergency shut-off valve device can also be integrated into the disk set valve device. A preferred embodiment of the fluid system is characterized in that the emergency shut-off valve device is designed as a differential pressure valve to which at least one disk set pressure and the supply pressure are applied in such a way that the fluid supply to the disk sets is interrupted when the supply pressure is a threshold value less than the disk set pressure . The emergency closing valve device can be designed as a slide valve or a seat valve. The slide valve is designed, for example, as a proportional valve with an open position and a closed position. When designed as a seat valve, the emergency closing valve device is designed, for example, as a simple check valve. The fluid supply to the disk sets is closed with the differential pressure in order to maintain the pressure on the disk sets for as long as possible in an emergency.

Another preferred exemplary embodiment of the fluid system is characterized in that the emergency shut-off valve device is connected in terms of control to an OR valve to which the disk set pressures of the variator are applied. The OR valve is advantageously arranged between the fluid supply lines of the variator.

Another preferred embodiment of the fluid system is characterized in that the emergency closing valve device comprises a valve closing body which can be moved between at least one closed position and an open position, and a sensor device with which a position of the valve closing body is monitored in order to initiate further emergency measures. The further emergency measures are carried out in addition to the closure of the emergency supply to the disk sets, advantageously immediately when the valve closing body begins to move. The further emergency measures are, for example, an active opening of the separating device and / or a torque reduction on a drive machine of the drive. As an alternative or in addition to a position signal that is detected with the sensor device, a pressure signal in one of the fluid supply lines can also be used to initiate further emergency measures.

Another preferred embodiment of the fluid system is characterized in that the disk set valve devices each have an emergency shut-off valve. is arranged. The two emergency shut-off valves are designed as differential pressure valves, for example.

Another preferred exemplary embodiment of the fluid system is characterized in that the two emergency closing valves are coupled to one another in terms of actuation. For this purpose, the emergency shut-off valves can, for example, comprise a common valve slide. The emergency shut-off valves can, however, also comprise valve slides which are coupled to one another.

According to a further preferred exemplary embodiment, the function of at least one emergency closing valve device is integrated into the disk set valve devices. The emergency shut-off valve function can be implemented, for example, in a further valve position and further return surfaces of the disk set valve devices.

Another preferred embodiment of the fluid system is characterized in that an emergency opening valve device is arranged between the fluid pump and the separating device, which serves to accelerate a passive emergency fluid pressure reduction at the separating device. The emergency opening valve device can be integrated into a clutch valve. The emergency opening valve device advantageously releases a tank connection or a low-pressure connection on the emergency opening valve device, so that a rapid pressure reduction takes place at the separating device in the direction of the tank or low pressure. With regard to the emergency fluid pressure reduction, passive means that no valve force is required directly or indirectly via a pilot valve to open the emergency opening valve device in the direction of the tank or low pressure. The emergency opening function is implemented, for example, via an additional return surface on a clutch pressure valve.

Another preferred exemplary embodiment of the fluid system is characterized in that the emergency opening valve device is designed as a differential pressure valve which is subjected to at least one disk set pressure and the supply pressure. The emergency opening valve device particularly advantageously senses the same pressure difference as the emergency closing valve device. In this case, the emergency closing valve device is advantageously not tied to any sensor signal and is therefore advantageously not delayed by signal processing times. Another preferred exemplary embodiment of the fluid system is characterized in that the emergency closing valve device and the emergency opening valve device are coupled to one another in terms of actuation. The coupling can be realized by a common valve slide. However, different valve slides can also be mechanically coupled to one another in order to implement the actuation-related coupling.

In a method for actuating a variator and a separating device in a drive train with the aid of a previously described fluid system, the above-mentioned object is alternatively or additionally achieved in that a torque that can be transmitted in the drive train at the separating device is reduced more quickly than a corresponding transmittable torque on the variator.

Further advantages, features and details of the invention emerge from the following description in which various exemplary embodiments are described in detail with reference to the drawing. Show it:

FIG. 1 shows a schematic representation of a gear ratio component designed as a variator and a separating device between a drive and an output;

FIG. 2 shows a schematic representation of four torque curves in the event of an error; the

FIGS. 3 to 10 eight exemplary embodiments of a fluid system for actuating the transmission ratio component designed as a variator and the separating device in the drive train from FIG. 1; and

FIG. 11 shows a detailed fluid circuit diagram of the fluid system for actuating the transmission ratio component designed as a variator and the separating device in the drive train from FIG. In Figure 1, a drive train 10 with a drive unit 70 is shown schematically. The drive unit 70 comprises an internal combustion engine 11 and an electrical machine 12. A separating device 14, which is designed, for example, as a clutch, is arranged between the internal combustion engine 11 and the electrical machine 12.

The internal combustion engine 11 and the electrical machine 12, together with the separating device 14, represent a drive 13 in the drive train 10. Between the drive 13 and an output 17, a gear ratio component designed as a variator 15 and a separating device 16 are arranged. The variator 15 and the separating device 16 are actuated via a fluid system, which is shown in the figures

3 to 11 is shown in different exemplary embodiments.

Figure 2 shows schematically four torque curves 21 to 24. The torque curves 21 to 24 show the curves of transmittable torques in the drive train, which is shown in Figure 1, over time in the event of a fault, for example if an electric motor-driven fluid pump in the fluid system has failed is.

The torque curve 21 corresponds to a torque provided on the drive. The torque curve 24 corresponds to a torque provided at the output. The torque curve 22 corresponds to a limited torque on the variator in the event of a fault. The torque curve 23 corresponds to a limited torque on the separating clutch between the variator and the output in the event of a fault.

The fluid system 1 shown in various embodiments in FIGS. 3 to 11 comprises a fluid pump 2 driven by an electric motor.

4 controlled. The disk set valve device 3 is in a fluid supply line

5 arranged in front of the variator 15. The disk set valve device 4 is arranged in a fluid supply line 6 upstream of the variator 15.

The disk set valve devices 3, 4 are actuated electromagnetically and are biased into the valve position shown in each case by a spring device. Both disk set valve devices 3, 4 are assigned to the respective pressure Fluid supply line 5, 6 controlled. In addition to the connections of the fluid supply lines 5, 6, the disk set valve devices 3, 4 each include a tank connection as a third connection.

An emergency closing valve device 7 is arranged between the fluid pump 2 and the disk set valve device 3, 4. In addition, a clutch valve device 8 is arranged between the fluid pump 2 of the separating device 16, which is also referred to for short as a clutch valve.

The clutch valve 8 is electromagnetically actuated and biased into its position shown by a spring. In addition to two connections for an unmarked coupling supply line, the coupling valve 8 includes a tank connection as a third connection.

The same reference numerals are used in FIGS. 3 to 11 to denote the same or similar parts. The differences between the individual exemplary embodiments are discussed below.

In FIG. 3, the emergency closing valve device 7 is designed as a differential pressure valve 25 which passively compares the pressure upstream and downstream of the differential pressure valve 25. The differential pressure valve 25 is designed such that it separates the connection between the fluid pump 2 and the variator 15 or the disk set valve devices 3, 4 as soon as the inlet pressure is lower than the working pressure.

Via the symbolically indicated spring on the differential pressure valve 25, a specific pressure difference can also be maintained here, so that the differential pressure valve 25 already switches to its blocking division shown when the pressure drops, but is still certainly sufficient for the function. A pressure drop in the inlet caused by a power failure will thus close the differential pressure valve 25 immediately and maintain the pressure to the variator 15 for a certain time or, for example, slow down a pressure decrease caused by a leak compared to a pressure decrease in the inlet of the differential pressure valve 25. If a pressure drop is detected in one of the supply lines, the coupling valve 8 must be de-energized, provided that this has not already happened automatically as a result of the power failure of the supply. When the coupling valve 8 is not energized, the separating device 16, referred to as the coupling, is connected to the tank. In this way, the clutch torque can be reduced quickly in this position.

The unwanted pressure drop in the supply line can be monitored using a pressure sensor, which is indicated symbolically in FIGS. 3 to 10. As an alternative or in addition, position monitoring (not shown) can take place on an inlet valve of the variator supply. Parallel to the opening of the clutch valve 8, the torque on the prime mover can be reduced if a fault is detected.

In FIG. 4, as an alternative or in addition, an emergency opening valve device 26 is arranged in the actuating path to the separating device 16. The emergency opening valve device 26, like the emergency closing valve device 7, is designed as a differential pressure valve and is controlled with the same pressures as the differential pressure valve 25 of the emergency closing valve device 7. Thus, the emergency opening valve device 26 is switched passively according to the same conditions as the emergency closing valve device 7 in the event of an undesired pressure drop in the supply .

The emergency opening valve device 26 is arranged between the clutch valve 8 and the separating device 16. In an emergency, the coupling line is short-circuited to the tank by the emergency opening valve device 26. This happens almost simultaneously with the closing of the supply line in the variator 2. Since the two valve devices 7 and 26 in FIG. 4 sense the same pressures, they could also be mechanically coupled or combined in one valve.

In FIG. 5, the differential pressure valve 25 of the emergency closing valve device 7 is activated via an OR valve 28. The OR valve 28 is connected between the fluid supply lines 5, 6 of the variator 15. The higher of the two disk set pressures automatically triggers the desired emergency function of the emergency shut-off valve device 7 in the event of a pressure drop in the supply. In FIG. 6, the emergency closing valve device 7 comprises two differential pressure valves 31, 32 which are connected upstream of the disk set valve devices 3, 4. This also ensures that if the supply pressure fails, no volume flow can flow from one set of pulleys to the other, and the variator thus unintentionally changes its gear ratio.

FIGS. 7 and 8 show that the exemplary embodiments shown in FIGS. 5 and 6 can also be combined with one another in different ways. This ensures that the higher consumer pressure always acts simultaneously on the two differential pressure valves 31, 32 via the OR valve 28.

In Figure 7, in contrast to Figure 6, a pressure return of the differential pressure valves 31, 32 via the OR valve 28 is also provided. In FIG. 8, the differential pressure valves 31, 32 of the emergency closing valve device 7 are coupled to one another for the sake of simplicity. This means that two pressure control lines can be omitted. Valve closing bodies 34 of the differential pressure valves 31, 32 are mechanically coupled to one another by a coupling rod, which is indicated by two connecting lines.

FIG. 9 shows that the emergency closing valve device 7 can also be designed as a simple non-return valve 36. The check valve 36 is preloaded, for example by a spring, in such a way that it opens towards the variator 15 and closes in the opposite direction, that is towards the fluid pump 2. The check valve 36 is designed as a seat valve.

In FIG. 10 it is shown that the emergency closing valve device 7 can also be combined with or integrated into the disk set valve devices 3, 4. The pressure control of the emergency shut-off valve device 7 combined with the disk set valve devices 3, 4 takes place via an OR valve 28.

In FIG. 11, the disk set valve devices 3, 4 each include a main valve 41, 42 which is pilot-controlled by a pilot valve 43, 44. By symbols 45 are fluidic capacities indicated, which can optionally be arranged at different points in the fluid system 1. For example, the fluid supply lines 5, 6 are each assigned a fluidic capacity 45. The supply pressure, which is provided with the fluid pump 2 driven by an electric motor, is set via a system pressure valve 46. A main pressure valve 47 is connected upstream of the pilot operated disk set valve devices 3, 4. The separating devices 14, 16, which, like the variator 15, are only indicated by the respective reference characters, are controlled via clutch valves 48, 49.

The fluid system 1 can supply other consumers 50 with fluid. An additional fluid pump 52, which, as shown, is advantageously driven by an electric motor together with the fluid pump 2, is used with the system pressure valve 46 to represent a cooling function 51 Assigned inflow.

Bezuqszeichenliste Fluid system Fluid pump Disc set valve device Disc set valve device Fluid supply line Fluid supply line Emergency closing valve device Clutch valve Drive train Internal combustion engine Electric machine Drive Separating device Gear ratio component, in particular variator Separating device output Torque curve Torque curve Torque curve Torque curve Differential pressure valve Emergency opening valve device Or valve Differential pressure valve Differential pressure valve Valve closing valve Check valve Fla main valve Pilot valve fluidic capacities System pressure valve Main pressure valve Clutch valve Clutch valve Additional consumers Cooling function Additional fluid pump Disk set Disk set Supply pressure area Gear pressure area Separation pressure area Gear pressure valve device Differential pressure valve Drive unit

Claims

1. A method for actuating a transmission gear component (15) and a separating device (16) in a drive train (10) with the aid of a fluid system (1) which has a supply pressure area (60) in which an electric motor-driven fluid pump (2) a supply pressure is provided, a transmission pressure area (61) assigned to the transmission gear component (15) and a separation pressure area (62) assigned to the separating device (16), characterized in that in an emergency a torque transmission via the transmission gear component (15) by opening the separating device (16) or by engine intervention on a drive unit (70) in the drive train (10).

2. The method according to claim 1, characterized in that the pressure in the transmission pressure area (61) is compared with the supply pressure in the supply pressure area (60) in order to identify an emergency situation and initiate emergency measures.

3. The method according to claim 1 or 2, characterized in that the transmission pressure area (61) is separated from the supply pressure area (60) at a significant pressure drop in the supply pressure in the fluid system (1) as part of a first emergency measure, with a Second emergency measure at the same time the pressure in the separating pressure area (62) is reduced so that a torque which can be transmitted in the drive train (10) at the separating device (16) is reduced more quickly than a corresponding transmittable torque at the transmission gear component (15).

4. The method according to any one of the preceding claims, characterized in that the pressure in the transmission pressure range (61) is included.

5. Fluid system (1) for actuating a transmission gear component (15) and a separating device (16) in a drive train (10), with at least one electric motor-driven fluid pump (2), which provides a supply pressure in the fluid system (1), and with a transmission pressure valve inlet direction (65), characterized by an emergency shut-off valve device (7) which serves to passively slow down an emergency fluid pressure reduction in a transmission pressure range (61).

6. Fluid system according to claim 5, characterized in that the emergency closing valve device (7) comprises at least one differential pressure valve (25; 31,32) via which the transmission pressure area (61) is passively separated from the supply pressure area (60).

7. Fluid system according to claim 6, characterized in that an emergency valve device (26) comprises at least one differential pressure valve (66), via which the separating pressure area (62) is passively relaxed.

8. Fluid system according to claim 6 or 7, characterized in that the differential pressure valve (25; 31, 32) and / or the differential pressure valve (66) are / is equipped with a position detection system in order to actively reduce the pressure in the separating pressure area (62 ) and / or trigger a drive intervention.

9. Fluid system according to one of claims 5 to 8, characterized in that a pressure return from the transmission pressure area (61) picks up a control pressure upstream or downstream of the transmission pressure valve device (65).

10. Fluid system according to one of claims 5 to 9, characterized in that the transmission pressure valve device (65) comprises two transmission pressure valves (3, 4) to which an OR valve (28) is assigned, via which only the higher of two transmission pressures in the transmission pressure range (61) is fed back.