Actuating device and method for operating fluid device and actuating device

Abstract

The invention relates to a method for operating a fluid device (10) of a vehicle, to a method for operating an actuating device (20), and to an actuating device (20).

Description

Technical Field

[0001] This invention relates to a method for operating a fluid device according to claim 1. The invention also relates to a method for operating an actuating device and an actuating device itself. Background Technology

[0002] DE 10 2020 111 970 A1 describes a hydraulic device that supplies actuating fluid pressure to an actuating device. A hybrid-mode clutch is actuated according to the actuating fluid pressure. A release valve is actuated to open the hybrid-mode clutch, thereby creating a pressure drop under the actuating fluid pressure. Summary of the Invention

[0003] The purpose of this invention is to limit excessively high actuation fluid pressure. During this process, the actuating device should be kept in an actuated state as much as possible.

[0004] At least one of the above objectives is achieved by a method for operating an actuating device having the features described in claim 1. This limits the upper limit of the actuating fluid pressure. Pressure increases in the actuating fluid due to temperature effects can be limited.

[0005] Fluid equipment can be hydraulic equipment. The fluid can be hydraulic fluid. The fluid can be oil, especially hydraulic oil.

[0006] The vehicle can be a motor vehicle, especially a hybrid vehicle or an electric vehicle.

[0007] The fluid pump can be a gear pump. The fluid pump can be a reversible pump. In a first pump operation, the fluid pump can generate a fluid volumetric flow rate for establishing actuating fluid pressure. In a second pump operation, the fluid pump can supply a fluid volumetric flow rate to at least one cooling device. The fluid pump can alternately switch between the first and second pump operations. The fluid pump can be driven by an electric motor.

[0008] The actuating device can be a clutch, especially a friction clutch or a claw clutch. The clutch can be a disengaged clutch, especially a K0 clutch in a hybrid powertrain. The actuating device can have a concentric driven cylinder (CSC) actuator.

[0009] The actuating fluid pressure can be the clutch actuating pressure.

[0010] The first actuation state enables the clutch to be engaged. The second actuation state enables the clutch to be disengaged.

[0011] A pressure relief valve can be a release valve.

[0012] The first pressure relief valve state corresponds to a fully open pressure relief valve. The third pressure relief valve state is neither fully open nor fully closed.

[0013] Overpressure valves are not required in fluid equipment, or at least not for limiting the pressure of the actuating fluid.

[0014] In a preferred embodiment of the invention, it is advantageous that the actuating fluid pressure is at least higher than a first actuating pressure value throughout the first actuation state and at least lower than a second actuating pressure value throughout the second actuation state. If the actuating fluid pressure is lower than the first actuating pressure value, the system can exit the first actuation state and move towards the second actuation state. If the actuating fluid pressure is higher than the second actuating pressure value, the system can exit the second actuation state and move towards the first actuation state.

[0015] A preferred design of the present invention has the following advantages: when the actuating fluid pressure reaches or exceeds a third actuating pressure value, which is greater than the first actuating pressure value, a third pressure relief valve state is set. When the actuating pressure value reaches or falls below a fourth actuating pressure value, the third pressure relief valve state can be deactivated, particularly the first pressure relief valve state can be used. The fourth actuating pressure value can be greater than or equal to the first actuating pressure value. The fourth actuating pressure value is less than the third actuating pressure value.

[0016] In a particular embodiment of the invention, it is advantageous to set the third pressure relief valve state based on the state of the first pressure relief valve. Therefore, the third pressure relief valve state can be set based on a closed pressure relief valve.

[0017] A preferred embodiment of the invention has the advantage of maintaining the first actuation state during the third pressure relief valve state. For example, the clutch can remain closed during the third pressure relief valve state. With the third pressure relief valve state, the actuation fluid pressure can be slowly reduced without falling below the first actuation pressure value. The third pressure relief valve state can be adopted and maintained without leaving the first actuation state. The third pressure relief valve state can be maintained for a predetermined period of time.

[0018] In a preferred embodiment of the invention, it is advantageous that the set time period for the third pressure relief valve state depends on the change in actuation fluid pressure. If the actuation fluid pressure does not drop to a predetermined actuation pressure value within the predetermined time period, a second pressure relief valve state can be adopted based on the third pressure relief valve state. In this case, an error may be output.

[0019] During the third pressure relief valve state, the pressure relief valve can be in a constant partially open state or in a partially open state that varies over time.

[0020] A preferred embodiment of the present invention has the following advantages: the pressure relief valve is electrically operated to change its state. The pressure relief valve can be controlled by current regulation. The third pressure relief valve state can be set by electrically operating the pressure relief valve, particularly based on the first pressure relief valve state.

[0021] In a preferred embodiment of the invention, the electrical control for employing the third pressure relief valve state has at least one electrical operating variable that differs from the electrical control for employing the first pressure relief valve state. Thus, the third pressure relief valve state can be employed in a controlled manner.

[0022] A preferred design of the present invention has the following advantages: the electrical operating variable is a pulse width modulation (PWM) or a PWM parameter. The electrical operating variable can be current. Pulse width modulation allows setting the desired current.

[0023] Furthermore, within the scope of this invention, in order to achieve at least one of the above-mentioned objectives, a method for operating an actuation device for a vehicle is proposed, the method being operated according to an actuation fluid pressure set by a method for operating a fluid device having at least one of the above-mentioned features.

[0024] Furthermore, within the scope of this invention, in order to achieve at least one of the above objectives, an actuation device for a vehicle is proposed, the actuation device being configured to operate by the previously described method for operating the actuation device.

[0025] Other advantages and advantageous designs of the invention are apparent from the accompanying drawings. Attached Figure Description

[0026] The present invention will now be described in detail with reference to the accompanying drawings. Specifically, it is shown that: Figure 1 A fluid device according to a specific embodiment of the present invention.

[0027] Figure 2 A diagram illustrating a method for operating a fluid device in a particular embodiment of the invention. Detailed Implementation

[0028] Figure 1 A fluid device according to a specific embodiment of the invention is shown. The fluid device 10 is arranged in a vehicle and is implemented as a hydraulic device 12 having hydraulic fluid. The fluid device 10 includes a fluid pump 14 driven by an electric motor 16, which is electrically controlled by a motor controller 18.

[0029] The fluid device 10 also includes an actuation device 20, which can switch between a first actuation state 22 and a second actuation state 24 based on an actuation fluid pressure p formed by the fluid volume flow rate provided by the fluid pump 14. In the first actuation state, the actuation device 20 is in an actuated state (shown in the dashed area in the figure), and in the second actuation state, the actuation device 20 is in a non-actuated state. The actuation device 20 is, for example, a clutch actuation device 26 of a clutch 28, and the actuation fluid pressure p is the clutch actuation pressure. The actuation device 20 includes a CSC actuator having a driven cylinder piston 30 that is displaceable according to the actuation fluid pressure p.

[0030] The fluid volumetric flow rate is drawn from the fluid reservoir 32 by the fluid pump 14. At this time, a suction-side filter 34 is arranged between the fluid reservoir 32 and the fluid pump 14. The fluid pump 14 is implemented as a reversible pump, which, in a first pump operation, forms a fluid volumetric flow rate for forming an actuating fluid pressure p, and in a second pump operation, forms a fluid volumetric flow rate for supplying other vehicle components, such as, in particular, the cooling device 36 for cooling the ring gear teeth 38, the hollow shaft bearing 40, and the electric motor 42. The fluid is cooled by a heat exchanger 44.

[0031] An electrically operable switching valve 46 is arranged between the fluid pump 14 and the actuating device 20. The switching valve 46 controls the fluid volume flow rate between the fluid pump 14 and the actuating device 20, as well as another actuating device 48 assigned to the parking lock device 50.

[0032] The fluid device 10 includes a controllable pressure relief valve 52, which can be switched at least between a first pressure relief valve state C1 (when pressure relief valve 52 is closed) and a second pressure relief valve state C2 (when pressure relief valve 52 is open). In the first actuation state 22, pressure relief valve 52 has the first pressure relief valve state C1, i.e., pressure relief valve 52 is closed. To enable a second actuation state 24 based on the first actuation state 22, pressure relief valve 52 has the second pressure relief valve state C2, i.e., open, thereby reducing the actuating fluid pressure p, and clutch 28 is disengaged. In the first actuation state 22, clutch 28 is engaged, and because pressure relief valve 52 is closed, the actuating fluid pressure p remains above a first actuation pressure value, from which the first actuation state 22 begins. Switching valve 46 prevents fluid backflow into fluid reservoir 32 and prevents a drop in actuating fluid pressure p. Temperature effects may cause the actuating fluid pressure p to increase.

[0033] During the first actuation state 22, the third pressure relief valve state is set according to the actuation fluid pressure p, at which time the pressure relief valve 52 is partially opened. This allows the excessively high actuation fluid pressure p to be reduced without changing the actuation state.

[0034] Figure 2A diagram is shown illustrating a method for operating a fluid device in a particular embodiment of the invention. Figure 2 a) Shows the time curve of the actuating fluid pressure p. Figure 2 b) shows the time curve of the fluid temperature T with the actuating fluid pressure p. Figure 2 c) shows the time-varying current I as an electrical operating variable used to control the pressure relief valve. Figure 2 d) shows the pressure relief valve state C as it changes over time.

[0035] Before time t0, the pressure relief valve is in the open state, i.e., in the second pressure relief valve state C2. The current I used to operate the pressure relief valve is zero. Starting from time t0, the pressure relief valve is operated, and the current I increases. Therefore, the pressure relief valve is in the first pressure relief valve state C1, i.e., closed. By operating the fluid pump and closing the pressure relief valve, the actuating fluid pressure p further increases and exceeds the first actuation pressure value p1 at time t1. From this point onward, the first actuation state is adopted, and for example, the clutch is engaged.

[0036] Throughout the first actuation state, the actuation fluid pressure p is at least higher than the first actuation pressure value p1; throughout the second actuation state, the actuation fluid pressure p is at least lower than the smaller second actuation pressure value p2.

[0037] Starting at time t1, the first actuation state is adopted and maintained by sustaining the actuation fluid pressure p. Starting at time t2, the fluid temperature T begins to rise sharply, thereby increasing the actuation fluid pressure p. If the actuation fluid pressure p reaches a third actuation pressure value p3 at time t3, which is greater than the first actuation pressure value p1, then the third pressure relief valve state C3 is set based on the first pressure relief valve state C1, at which point the pressure relief valve is partially open. Here, the first actuation state remains set, i.e., the clutch is in the closed state.

[0038] The third pressure relief valve state C3 is set via an electrically operated pressure relief valve, which is achieved here by changing the electrical operating variable (equivalent to current I in this example). Current I decreases starting at time t3, thus setting the third pressure relief valve state C3 and correspondingly partially opening the pressure relief valve, reducing the actuating fluid pressure p until time t4 reaches the fourth actuating pressure value p4, which is specifically equivalent to the first actuating pressure value p1. Thereafter, by increasing current I, the first pressure relief valve state C1 is set again.

[0039] This process can be repeated multiple times as needed, especially when the actuating fluid pressure p reaches or exceeds the third actuating pressure value p3.

[0040] List of reference numerals 10 Fluid Equipment 12 Hydraulic Equipment 14 fluid pumps 16 electric motors 18 motor controllers 20 Actuation Devices 22 First Actuation State 24 Second Actuation State 26 Clutch Actuation Equipment 28 clutch 30 driven cylinder 32 fluid storage tank 34 filters 36 Cooling Equipment 38 ring gears 40 hollow bearing 42 electric motors 44 heat exchanger 46 Switching Valve 48 Another actuating device 50 parking lock devices 52 pressure relief valve C. Pressure relief valve status C1 First pressure relief valve status C2 Second Pressure Relief Valve Status C3 Third Pressure Relief Valve Status I current T fluid temperature p-actuating fluid pressure p1 First Actuation Pressure Value p2 Second Actuation Pressure Value p3 Third Actuation Pressure Value p4 Fourth Actuation Pressure Value

Claims

1. A method for operating a fluid device (10) of a vehicle, comprising: providing a fluid device (10) having a fluid pump (14), an actuation device (20) switchable between a first actuation state (22) in which the actuation device (20) is in an actuated state and a second actuation state (24) in which the actuation device (20) is in a non-actuated state depending on an actuation fluid pressure (p) formed by a fluid volume flow provided by the fluid pump (14), and having a controllable pressure relief valve (52) switchable at least between a first pressure relief valve state (Cl) in which the pressure relief valve (52) is closed and a second pressure relief valve state (C2) in which the pressure relief valve (52) is open, and having the first pressure relief valve state (Cl) in the first actuation state (22); and for assuming the second actuation state (24) based on the first actuation state (22), having the second pressure relief valve state (C2), wherein during the first actuation state (22), a third pressure relief valve state (C3) is set depending on the actuation fluid pressure (p) in which the pressure relief valve (52) is partially open, thereby reducing the actuation fluid pressure (p).

2. The method of claim 1, wherein, the actuation fluid pressure (p) is at least above a first actuation pressure value (pl) during the entire first actuation state (22) and is at least below a second actuation pressure value (p2) during the entire second actuation state (24).

3. The method of operation according to claim 1 or 2, characterized in that, the third pressure relief valve state (C3) is set when the actuation fluid pressure (p) reaches or exceeds a third actuation pressure value (p3) which is greater than the first actuation pressure value (pl).

4. The method of operation according to any of the preceding claims, characterized in that, the third pressure relief valve state (C3) is set based on the first pressure relief valve state (Cl).

5. The method of operation according to any of the preceding claims, characterized in that, the first actuation state (22) is maintained during the third pressure relief valve state (C3).

6. The method of operation according to any of the preceding claims, characterized in that, the pressure relief valve (52) is electrically controllable to change the pressure relief valve state (C).

7. The method of operation of claim 6, wherein, the electrical controllability for assuming the third pressure relief valve state (C3) has at least one electrical operating variable (I) which is different from the electrical controllability for assuming the first pressure relief valve state (Cl).

8. The method of operation according to any of the preceding claims, characterized in that, a time period of the setting of the third pressure relief valve state (C3) depends on a change of the actuation fluid pressure (p).

9. A method for operating an actuation device (20) of a vehicle, the method being operated depending on an actuation fluid pressure (p) set by a method for operating a fluid device (10) according to any of the preceding claims.

10. An actuation device (20) for a vehicle, the actuation device being configured to be operated by a method for operating an actuation device (20) according to claim 9.

Images