WO2015043590A1

WO2015043590A1 - Hydrostatic clutch actuator

Info

Publication number: WO2015043590A1
Application number: PCT/DE2014/200448
Authority: WO
Inventors: Matthias Ehrlich
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2013-09-24
Filing date: 2014-09-08
Publication date: 2015-04-02
Also published as: CN105579728A; JP2016532060A; DE112014004374A5

Abstract

The invention relates to a hydrostatic clutch actuator (1) for at least one friction clutch operatively arranged in a clutch bell (4) between a crankshaft of an internal combustion engine and a transmission input shaft of a transmission. In particular, the invention relates to two friction clutches of a double clutch containing at least one electrical drive unit (10, 11), at least one transmission (16, 17) that changes a rotational movement of the drive unit into a linear movement, at least one master cylinder (30, 31) actuated by the transmission, and at least one slave cylinder (34, 35) that is actuated by the master cylinder via a hydraulic section, concentrically arranged about the transmission input shaft and actuates the at least one friction clutch. In order to reduce costs and advantageously exploit the available assembly space, master cylinders and slave cylinders are arranged inside the clutch bell, and drive units and transmissions are arranged outside the clutch bell, and the at least one master cylinder is driven in a linear manner through a feed-through of the clutch bell.

Description

Hydrostatic clutch actuator

The invention relates to a hydrostatic clutch actuator for at least one in a clutch bell between a crankshaft of an internal combustion engine and a transmission input shaft of a transmission operatively arranged friction clutch, in particular two friction clutches of a dual clutch containing at least one electric drive unit, at least one rotational movement of the drive unit in a linear motion converting gear, at least a master cylinder actuated by the transmission and at least one slave cylinder actuated by the master cylinder via a hydraulic circuit and actuating the at least one friction clutch, arranged concentrically around the transmission input shaft.

In powertrains of motor vehicles friction clutches between the crankshaft of an internal combustion engine and the transmission input shaft of a transmission are used to decouple the engine from the transmission in the state of the motor vehicle, compensate for gearshifts differential gears and at frictional engagement of the friction clutch, the applied torque of the internal combustion engine via the transmission to transmit the drive wheels. In drive trains with dual-clutch transmission, two friction clutches combined in a double clutch and arranged between in each case one transmission input shaft of a partial drive train of the dual-clutch transmission and the crankshaft continue to distribute the torque of the internal combustion engine to the two partial drive trains. In such drive trains, the friction clutches are each operated automatically by the friction clutches are opened, closed or slipping operated depending on control signals of a control unit by means of a clutch actuator. Here, for example, hydrostatic clutch actuators have proved advantageous, as they are known for example from DE 10 201 1 014 932 A1. Here, a unit of a drive motor, a Planetenwälzgetriebe and a master cylinder outside a arranged between the engine and the transmission clutch bell which receives the friction clutch is arranged. Via a hydraulic line such as pressure line, a slave cylinder arranged around the transmission input shaft is actuated depending on the pressure generated in the master cylinder. The master cylinder is actuated by the drive motor, wherein the planetary gear reduction converts the rotary drive of the drive unit such as drive motor converts into a linear movement, which linearly displaces a piston rod and thus a piston of the master cylinder. Such units require, especially when using two copies in a drive train with dual clutch transmission in the engine compartment of the motor vehicle, a large space.

The object of the invention is the advantageous development of a hydrostatic clutch actuator with improved space utilization and to reduce manufacturing costs.

The object is solved by the device of claim 1. The dependent of the claim 1 claims give advantageous embodiments of the device again.

The proposed hydrostatic clutch actuator is provided for the actuation of at least one, in particular two designed as a double clutch, in a clutch bell between a crankshaft of an internal combustion engine and one or two concentrically nested transmission input shafts of a transmission effectively arranged friction clutches. The hydrostatic clutch actuator contains at least one, in the case of a double clutch to be actuated, two electric drive units, for example drive motors with a stator and a rotor rotatable relative thereto. The rotational movement of the rotor is converted by means of a gear in a linear movement. In this way, the drive unit actuates a master cylinder via the transmission, wherein, for example, a master cylinder piston received in a master cylinder housing is displaced linearly by means of a piston rod and a pressure medium enclosed in a master cylinder piston and master cylinder housing pressure medium is compressed. Via a hydraulic line, for example a pressure line, the pressure volume is connected to a friction clutch actuated, concentrically arranged around the transmission input shaft slave cylinder so that a slave cylinder piston is displaced depending on the applied pressure and thus the friction clutch is actuated by, for example by means of an actuating bearing such as or release bearing lever elements such as plate or lever spring tongues are acted upon axially.

An improved installation situation is achieved by a hydraulic unit formed from at least one master cylinder and at least one slave cylinder within the clutch bell and one from at least one drive unit and at least one transmission formed mechanical unit are arranged outside the clutch bell and the at least one master cylinder is linearly driven by a passage of the clutch bell. In this way, available space can be used in the clutch bell, so that outside the clutch bell only the mechanical or electrical components of the clutch actuator are to be accommodated, so that the space available in the engine compartment of the motor vehicle space is less stressed by the clutch actuator. Furthermore, the hydraulic distance between the master cylinder and the slave cylinder is shorter, so that, for example, an improved pressure transmission, for example an improved temperature dependency, lower cable widening and the like, can be achieved.

In a particularly advantageous manner, at least one slave cylinder and at least one master cylinder can be accommodated in a common housing. In this way, a pressure line completely and two housings can be saved, so that a cost reduction can be achieved. The common housing may be made of plastic in accordance with the individual housings of donor and slave cylinders preferably made by injection molding. The housing may be formed integrally or in several parts to avoid complicated injection molds. The housing may be attached to the transmission housing, so that only once attachment means are provided. The housing preferably supports the actuating forces of the friction clutch (s) against the transmission housing.

To convert the rotational movement of the drive unit into a linear movement, the at least one gear can be configured as a spindle drive with a rotationally fixed and axially displaceable spindle rotatably mounted by the at least one drive unit, axially fixed for example by means of at least one axial fixed bearing mounted rotatably in a motor housing. In this case, the spindle can drive a piston rod of the at least one master cylinder linear. Between spindle and piston rod, a joint such as ball or calotte joint can be arranged to compensate for any existing angular misalignments between the spindle and piston rod. Ideally, the spindle is coaxial with the piston rod and thus arranged coaxially with the master cylinder piston.

In addition to a conversion of the rotary motion into a linear motion one

Reduction of the transmission can provide the spindle drive as Planetenwälz- gearbox be formed with a rotor of the drive unit forming and by means of Planetenwalzkorpern the spindle driving spindle nut. In this case, planetary rolling bodies arranged distributed over the circumference roll by means of a straight toothing without a pitch relative to the spindle nut driven by the drive unit and by means of a thread toothing on the spindle. For detailed construction of a Planetenwälzgetriebes reference is made, for example, to DE 10 201 1 014 932 A1 and DE 10 2010 047 801 A1.

It can be provided an electromechanical unit of the clutch actuator formed from the drive unit and the transmission, which is housed in a separate housing outside the clutch bell and fixed to the housing, for example, received on the engine housing of the internal combustion engine or on the transmission housing of the vehicle transmission. In addition, in this case, one of the electromechanical unit associated control board may be provided, which forms a clutch control unit or communicates with this and controls the drive unit. Due to the direct kinematic assignment of spindle, piston rod and slave cylinder piston via the hydrostatic path, an absolute displacement sensor can be provided on the control board, which detects an absolute linear path of the spindle. In addition, the piston paths of slave and master cylinder can be detected absolutely. It is understood that between the slave and master cylinder, a sniffer may be provided, compensated in the temperature-related volume expansions of the pressure medium by temporarily starting a compensation opening and possibly resulting gas bubbles are removed from the hydraulic path. Furthermore, for monitoring the rotational characteristics such as rotational angle, rotational speed and rotational acceleration between rotor and housing, a rotational angle sensor, for example, a Drehwinkelinkremente detecting rotational angle sensor may be provided to control, for example, designed as electronically commutated electric motor drive unit and / or the rotational characteristics of the spindle nut relative to the spindle to detect and thus detect, for example, in conjunction with the Absolutwegsensor slippage of Planetenwälzgetriebes. The rotation angle sensor may be provided axially extended on the rotor, so that a relative rotation between markings of the rotor and on the control board provided detection elements of the rotation angle sensor can be provided. Furthermore, a so-called target can be provided to form the absolute travel sensor on the spindle, which interacts with detection elements of the absolute travel sensor on the control board. The piston of the slave cylinder may be formed as arranged around the transmission input shaft coaxial annular piston. Alternatively, a plurality of cylindrical individual pistons arranged around the circumference and arranged on two or a single pitch circle may be provided around the transmission input shaft, said individual pistons communicating with a common pressure volume of the slave cylinder. The slave cylinder piston contains an actuating bearing or is applied to an actuating bearing and acts on the friction clutch depending on the training as a depressed or compressed friction clutch in the open or closed position.

In a preferred embodiment, two electromechanical and hydrostatic units which are essentially identical in terms of their function and structure are provided, in order to actuate a respective friction clutch of a double clutch independently of one another. For this purpose, two drive units and two gearbox are accommodated in a housing outside of the clutch bell and each two master cylinder and two arranged around two concentrically arranged transmission input shafts, each provided a friction clutch slave cylinder provided within the clutch bell.

Depending on the embodiment, single or multiple master cylinder and slave cylinder may be housed in a predetermined division in one or more separate housings. In a particularly advantageous manner, master cylinder and slave cylinder are accommodated in a single common housing. The housing may be formed in one piece or in several parts. The housing is fastened in a preferred manner to the transmission housing or is supported on this axially to counteract the actuating forces.

Both slave cylinders may have two radially superimposed annular piston. However, it has proved to be advantageous to form at least one slave cylinder piston distributed over the circumference arranged individual piston such as cylindrical pressure piston.

The formation of the pressure lines between the master cylinders and slave cylinders can be carried out in the manner, for example, radially or tangentially, that the two master cylinder are arranged parallel spaced from each other. In this way, two directly juxtaposed outside of the clutch bell electromechanical units, which are arranged space-saving directly next to each other in a single housing can. A common pressure equalization tank can be provided between the donor cylinders to save space.

The invention will be explained in more detail with reference to the embodiment shown in Figures 1 to 3. Showing:

1 shows a hydrostatic clutch actuator in a schematic representation,

Figure 2 shows a mounting situation of the hydrostatic clutch actuator of Figure 1 with

Looking towards gearbox housing

and

Figure 3 shows a mounting situation of the hydrostatic clutch actuator of Figure 1 with

View from the side.

FIG. 1 shows the hydrostatic clutch actuator 1 from the transmission side in a schematic view. The hydrostatic clutch actuator 1 is used to actuate two friction clutches of a double clutch and each has an actuator unit 2, 3 for a friction clutch. The actuator units 2, 3 are each formed of an electromechanical unit 5, 6 arranged outside the clutch bell 4 and a hydrostatic device 7, 8 arranged inside the clutch bell 4. The electromechanical units 5, 6 are accommodated in a common housing 9, which is fixedly connected to the clutch bell 4 or otherwise firmly connected to the internal combustion engine or the vehicle transmission.

The electromechanical units 5, 6 are constructed essentially identically and have the drive unit 10, 11 formed as an electric motor with the stator 12, 13 permanently connected to the housing 9 and the rotor 14, 15. Radially inside the stator 12, 13 is designed as Planetenwälzgetriebe 18, 19 gears 16, 17 arranged to convert the rotational and rotational movement of the rotor 14, 15 in a linear movement. In this case, the rotor 14, 15 by means of the fixed bearing 20, 21, the rotatably and axially firmly received spindle nut 22, 23. Upon rotation of the spindle nut 22, 23 is rotatably and axially displaceably accommodated spindle 24, 25 by means not shown planetary rolling between spindle nut 22, 23 and spindle 24, 25 axially displaced. The spindles 24, 25 respectively pass through a passage 26, 27 in the clutch bell 4 and act on the piston rods 28, 29 of the master cylinders 30, 31 of the hydrostatic units 7, 8 provided coaxially with them. The master cylinders 30, 31 are arranged parallel to one another and spaced apart from one another by the electromechanical units 5, 6, in order in each case to permit a coaxial arrangement of spindles 24, 25 and piston rods 28, 29. The master cylinder 30, 31 and slave cylinder 34, 35 are received in the embodiment shown in a single housing 36, so that the pressure lines 32, 33, the pressure lines 32, 33 act upon the pressure lines 32, 33, respectively, a slave cylinder 34, 35 associated therewith. 33 can be formed short and stiff. Between the master cylinders 30, 31 of the common pressure equalization tank 37 is arranged. The pressure lines 32, 33 are radially or at right angles tangentially into corresponding, non-visible pressure volumes of the slave cylinder 34, 35 out. Here, the master cylinder pistons 38, 39 move perpendicular to the slave cylinder pistons of the slave cylinders 34, 35, which move axially relative to the axis of rotation d of the friction clutches.

The linear movement of the spindles 24, 25 and thus the linear travel of the master cylinder pistons 38, 39 and over the hydraulic distance of the slave cylinder pistons is detected by means of the absolute travel sensors 40, 41. For this purpose, a target 42, 43 is provided on the spindles 24, 25, and a detection element 44, 45 is provided on the control boards 46, 47. The rotational movement of the rotors 14, 15 and thus the spindle nuts 22, 23 is detected by means of the rotation angle sensors 48, 49. For this purpose, an axially expanded rotary encoder 50, 51 is provided on the rotor 14, 15, which interacts with a arranged on the control board 46, 47 detection element 52, 53.

Figures 2 and 3 show the installation situation of the hydrostatic clutch actuator 1 of Figure 1 with a view of the gear housing 54 with the clutch bell 4. Outside the clutch bell 4, the electromechanical units 5, 6 and within these the hydraulic units 7, 8 are arranged, in the view of the housing 9 (Figure 1) is omitted. As can be seen from FIG. 2, the slave cylinder pistons 55, 56 of the slave cylinders 34, 35 are provided as individual pressure pistons 57, 58 arranged over the circumference, which are alternately arranged on a single pitch circle over the circumference. The mechanical decoupling to form an independent operation of the friction clutches by means of the disengagement between slave cylinder piston 55, 56 and friction clutches. Reference character list hydrostatic clutch actuator

actuator

Kupplungsglocke

electromechanical unit

hydrostatic unit

casing

drive unit

stator

rotor

transmission

Planetenwälzgetriebe

fixed bearing

spindle nut

spindle

execution

piston rod

Master cylinder

Master cylinder pressure line

pressure line

slave cylinder

casing

Pressure balance tank Master cylinder piston Master cylinder piston Absolutwegsensor Absolutwegsensor Target

target

Detector element Detector element Control board

control board

Rotary Angle Sensor Rotary Angle Sensor Rotary Angle Encoder Rotary Encoder Detector Element Detector Gear Case Slave Cylinder Piston Slave Cylinder Piston Pressure Piston

pressure piston

axis of rotation

Claims

claims

1 . Hydrostatic clutch actuator (1) for at least one in a clutch bell (4) between a crankshaft of an internal combustion engine and a transmission input shaft of a vehicle transmission operatively arranged friction clutch comprising at least one electric drive unit (10, 1 1), at least one rotational movement of the drive unit (10, 1 1 ) in a linear motion converting gear (16, 17), at least one of the transmission (16, 17) actuated master cylinder (30, 31) and at least one of the master cylinder (30, 31) actuated via a hydraulic path, the at least one friction clutch actuating, concentrically arranged around the transmission input shaft slave cylinder (34, 35), characterized in that master cylinder (30, 31) and slave cylinder (34, 35) within the clutch housing (4) and drive unit (10, 1 1) and transmission (16, 17) are arranged outside the clutch bell (4) and the at least one master cylinder (30, 31) linearly dur a passage (26, 27) of the clutch bell (4) is driven.

2. Hydrostatic clutch actuator (1) according to claim 1, characterized in that at least one slave cylinder (34, 35) and at least one master cylinder (30, 31) are accommodated in a common housing (36).

3. Hydrostatic Kupplungsaktor (1) according to claim 1 or 2, characterized in that the at least one gear (16, 17) as a spindle drive with one of the at least one drive unit (10, 1 1) rotationally driven axially fixed spindle nut (22, 23) and a rotatably and axially displaceable spindle (24, 25) is formed and the spindle (24, 25) a piston rod (28, 29) of the at least one master cylinder (30, 31) linearly drives.

4. Hydrostatic Kupplungsaktor (1) according to claim 3, characterized in that the spindle drive as Planetenwälzgetriebe (18, 19) with a rotor (14, 15) of the drive unit (10, 1 1) forming and by means of Planetenwälzkörpern the spindle (24, 25) driving spindle nut (22, 23) is formed.

5. Hydrostatic clutch actuator (1) according to claim 3 or 4, characterized in that the at least one drive unit (10, 1 1) and the at least one gear (16, 17) and a control board (46, 47) for controlling the drive unit ( 10, 1 1) are received in a common housing (9) and an absolute travel sensor (40, 41) for detecting an absolute linear travel of the spindle (24, 25) on the control board (46, 47) is arranged.

6. Hydrostatic clutch actuator (1) according to one of claims 1 to 5, characterized in that for actuating two friction clutches of a dual clutch two drive units (10, 1 1) and two gears (16, 17) are accommodated in a housing (9) and two master cylinder (30, 31) and two arranged around two concentrically arranged transmission input shafts, in each case a friction clutch operated slave cylinder (34, 35) are provided.

7. Hydrostatic clutch actuator (1) according to claim 6, characterized in that the master and slave cylinders (30, 31, 34, 35) are accommodated in a common housing (36).

8. Hydrostatic clutch actuator (1) according to claim 6 or 7, characterized in that at least one of the slave cylinder (34, 35) distributed over the circumference arranged cylindrical pressure piston (57, 58).

9. Hydrostatic clutch actuator (1) according to one of claims 6 to 8, characterized in that between the master cylinders (30, 31) a common pressure equalization tank (37) is arranged.

10. Hydrostatic clutch actuator (1) according to one of claims 6 to 9, characterized in that the two master cylinders (30, 31) are arranged spaced from each other in parallel.