DE102015212161A1 - Hydraulic system of an automatic transmission - Google Patents

Hydraulic system of an automatic transmission

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Publication number
DE102015212161A1
DE102015212161A1 DE102015212161.5A DE102015212161A DE102015212161A1 DE 102015212161 A1 DE102015212161 A1 DE 102015212161A1 DE 102015212161 A DE102015212161 A DE 102015212161A DE 102015212161 A1 DE102015212161 A1 DE 102015212161A1
Authority
DE
Germany
Prior art keywords
pressure
pressure circuit
valve
hydraulic
valve unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
DE102015212161.5A
Other languages
German (de)
Inventor
Thilo Schmidt
Tim Rose
Markus Herrmann
Horst Rögner
Rolf Braun
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZF Friedrichshafen AG
Original Assignee
ZF Friedrichshafen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ZF Friedrichshafen AG filed Critical ZF Friedrichshafen AG
Priority to DE102015212161.5A priority Critical patent/DE102015212161A1/en
Publication of DE102015212161A1 publication Critical patent/DE102015212161A1/en
Pending legal-status Critical Current

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H61/00Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/68Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for stepped gearings
    • F16H61/684Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for stepped gearings without interruption of drive
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H61/00Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/0021Generation or control of line pressure
    • F16H61/0025Supply of control fluid; Pumps therefore
    • F16H61/0031Supply of control fluid; Pumps therefore using auxiliary pumps, e.g. pump driven by a different power source than the engine
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H61/00Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/02Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
    • F16H61/0202Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric
    • F16H61/0204Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal
    • F16H61/0206Layout of electro-hydraulic control circuits, e.g. arrangement of valves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H61/00Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/02Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
    • F16H61/0202Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric
    • F16H61/0251Elements specially adapted for electric control units, e.g. valves for converting electrical signals to fluid signals

Abstract

A hydraulic system (1) with at least two pressure circuits (2, 3) is described. A valve device (4) has a first valve unit (8) and a second valve unit (9), against which in each case the pressure (pHD) of a primary pressure circuit (2) is applied. The pressure (pHD) of the primary pressure circuit (2) acts on the first valve unit (8) counter to a control force (F8) in the direction of a first operating state, in which a first hydraulic pump (6) via the first valve unit (8) with a secondary pressure circuit ( 3), while the pressure (pHD) of the primary pressure circuit (2) acting on the second valve unit (9) against a control force (F9) in the direction of an operating condition of the second valve unit (9) can be applied, in which a second hydraulic pump (5 ) is connected to both the primary pressure circuit (2) and a low pressure circuit (10), wherein a response limit of the first valve unit (8), from which the first valve unit (8) from the pressure (pHD) in the primary pressure circuit (2) in the direction first operating state is performed, is smaller than a response limit of the second valve unit (9), from which the second valve unit (9) from the pressure (pHD) in the primary pressure circuit (2) in the direction of the first operating condition over is heard.

Description

  • The invention relates to a hydraulic system of an automatic transmission according to the closer defined in the preamble of claim 1. Art.
  • A system for optimizing the efficiency of an oil supply with at least two different oil pressure levels is out of the DE 100 41 386 A1 known. The system comprises at least two conveyors and at least one control slide with at least two sidepieces. Each of the sidepieces is assigned to one of the conveyors. Corresponding to the position of the waistings in the control slide, a division of the respective volume flows into the at least two pressure levels as a function of the oil requirement in the respective pressure level is carried out automatically for each of the delivery devices.
  • In the known system or hydraulic system of an automatic transmission, a primary pressure circuit via the control slide or a valve device is supplied with promoted by the two conveyors or hydraulic pumps hydraulic fluid with higher priority than a secondary pressure circuit. The delivery volume flow of the first hydraulic pump provided for supplying the secondary pressure circuit flows at positive pressure gradient between the delivery side of the first hydraulic pump and the primary pressure circuit at least partially via a check valve in the primary pressure circuit and is above a pressure in the primary pressure circuit at least partially feasible via the valve means in the secondary pressure circuit while the Connection between the first hydraulic pump and the primary pressure circuit is blocked at a positive pressure gradient between the primary pressure circuit and the delivery side of the first hydraulic pump via the check valve device.
  • However, the system or hydraulic system provided for reducing the pump receiving torque is disadvantageously conditionally adaptable to available installation spaces. The planned for the two conveyors common control slide is spatially separated by space arranged spatially arranged conveyors only in the vicinity of one of the conveyors and then connected via possibly undesirably long hydraulic fluid with the other remote from the control slide conveyor connected. Furthermore, the control slide is only conditionally adaptable to the hydraulic fluid volume requirements of the pressure circuits to be supplied via the control slide with hydraulic fluid, which has an overall limiting effect on the design of a hydraulic system to an undesired extent.
  • The present invention is therefore based on the object to provide a hydraulic system of an automatic transmission with at least two pressure circuits are available with the available space optimally usable and the interpretation of the desired extent to the hydraulic fluid volume requirements of at least two pressure circuits can be performed.
  • According to the invention, this object is achieved with a hydraulic system having the features of patent claim 1.
  • The hydraulic system of an automatic transmission according to the invention comprises at least two pressure circuits. A primary pressure circuit can be supplied with higher priority than a secondary pressure circuit via a valve device with hydraulic fluid delivered by two hydraulic pumps. The delivery volume flow of the provided for supplying the secondary pressure circuit first hydraulic pump flows at a positive pressure gradient between the delivery side of the first hydraulic pump and the primary pressure circuit at least partially via a check valve in the direction of the primary pressure circuit and is above a pressure of the primary pressure circuit at least partially feasible via the valve means in the secondary pressure circuits while the connection between the first hydraulic pump and the primary pressure circuit is blocked at a positive pressure gradient between the primary pressure circuit and the delivery side of the first hydraulic pump via the check valve device.
  • According to the invention, the valve device has a first valve unit and a second valve unit to which in each case the pressure of the primary pressure circuit is applied. The pressure of the primary pressure circuit acts on the first valve unit counter to a control force in the direction of a first operating state of this, at which the first hydraulic pump via the first valve unit to the secondary pressure circuit is connected, while the pressure of the primary pressure circuit to the second valve unit against a control force in the direction an operating state of the second valve unit can be applied acting in which the second hydraulic pump is connected to both the primary pressure circuit and with a low pressure circuit. A response limit of the first valve unit, from which the first valve unit is transferred from the pressure in the primary pressure circuit in the direction of the first operating state, is smaller than a response limit of the second valve unit, from which the second valve unit is converted by the pressure in the primary pressure circuit in the direction of the first operating state.
  • By the execution of the valve device with two valve units, the hydraulic system according to the invention with respect to the arrangement in the range of available space in the Compared to the known from the prior art hydraulic system with higher degree of freedom can be arranged. Thus, in the case of spatially separated hydraulic pumps, it is possible to arrange the respective valve unit assigned to a hydraulic pump directly in the region of the associated hydraulic pump and to carry out the hydraulic system according to the invention in a space-saving manner with short hydraulic lines in the area between the valve units and the hydraulic pumps.
  • Furthermore, the two valve units can be dimensioned independently of one another to the desired extent as a function of the hydraulic fluid volume requirements of the pressure circuits to be supplied with hydraulic fluid via the valve units and adapted to the delivery volume of the hydraulic pumps, which is not the case with the hydraulic system known from the prior art due to the one-piece design of the valve device is feasible.
  • According to the applied to the valve units control forces at least partially spring forces acting on the valve units spring means are the valve units over the entire operating range of the hydraulic system with a defined valve characteristic available.
  • If the control forces applied to the valve units result at least partially from pressures applied to the valve units, the valve characteristic of the valve units can be changed to the desired extent.
  • If, in each case, a pressure signal acting in the direction of the first operating states of the valve unit can be applied to the valve units, the valve characteristic of the valve units can again be adapted as required and adapted to the respectively present operating point of an automatic transmission.
  • In a space-saving operable and with little operating effort embodiment of the hydraulic system according to the invention, the valve units are mounted in a bore in series and have the same pressure characteristics.
  • Corresponds to the low pressure region of the suction side of the first hydraulic pump and / or the second hydraulic pump, the hydraulic system according to the invention with low power losses is operable.
  • In a further advantageous embodiment of the hydraulic system according to the invention, the low pressure region is connected to an oil sump of the automatic transmission, whereby preferably a temperature of the hydraulic fluid with little effort is possible and a dirt entry is reduced in the range of hydraulic pumps.
  • In order to avoid impermissibly high and an operation of an automatic transmission over the secondary pressure circuit supplied with hydraulic fluid assemblies, in a further advantageous embodiment of the hydraulic system according to the invention downstream of the first valve unit and upstream of the secondary pressure circuit designed as a constant pressure pressure relief valve or as a variable pressure relief valve provided which establishes a connection between the first valve unit and the low-pressure area above a defined or variable pressure limit.
  • If the same pressure signal can be applied to the valve units and to the valve, the hydraulic system according to the invention can be operated with little operating effort.
  • A pump receiving torque is particularly low in a main operating range of an automatic transmission formed with the hydraulic system according to the invention and the automatic transmission is therefore operable with high efficiency if at least approximately 70% of the total hydraulic pump and at least approximately 30% of the total hydraulic fluid volume flow that can be supplied to the hydraulic system via the second hydraulic pump Is available adjustable.
  • In the cost-effective embodiment of the hydraulic system according to the invention, the hydraulic pumps are designed as constant pumps.
  • If the hydraulic pumps are separate structural units which have a common drive, the hydraulic system according to the invention can again be adapted to existing installation spaces to the desired extent.
  • In a space-saving and executable as a compact module embodiment of the hydraulic system according to the invention, the hydraulic pumps form a structural unit.
  • A particularly space-saving embodiment of the hydraulic system according to the invention comprises hydraulic pumps which form a double-vane cell pump with separate delivery chambers.
  • In a structurally simple and space-saving embodiment of the hydraulic system according to the invention, the delivery volumes of the double vane pump via the contour of a cam ring are adapted to the hydraulic fluid volume requirements of the multi-pressure circuit of the secondary pressure circuit.
  • By means of the system according to the invention and at least one dual-circuit system, the system takes place Pressure supply of the automatic transmission such that the primary pressure circuit having a high pressure level, serves only to cover the primary leakage, while the secondary pressure circuit assumes a low pressure level in static operation. In this case, the secondary pressure circuit is maintained at the pressure level of the primary pressure circuit until the hydraulic fluid volume requirement of the primary pressure circuit is covered solely by the hydraulic pump assigned to the primary pressure circuit.
  • During switching operations in the region of an automatic transmission, during which the hydraulic fluid volume requirement in the region of the primary pressure circuit increases or is high, the pressure of the secondary pressure circuit via the associated valve unit in turn to the pressure level of the pressure in the primary pressure circuit can be raised, so that the higher hydraulic fluid volume requirement of the primary pressure circuit in turn by the Hydraulic pump is covered, over which in the saturated operating state of the primary pressure circuit of the secondary pressure circuit is supplied with hydraulic fluid volume.
  • In principle, the hydraulic system according to the invention comprises two separate pressure circuits, each supplied with a hydraulic pump, each pressure circuit being regulated by a separate slide.
  • Since the pressure level in the area of the pressure circuits is very different in most driving cycles, the pressure of the primary pressure circuit and the secondary pressure circuit to a desired extent, a reduction of the pump pickup torque, for example, compared to a so-called single-circuit pump achieved by a separate pressure control.
  • In a preferred embodiment, the two valve units, preferably designed as limiting valves, can be varied in their pressure level via one or more pilot valves, wherein they have a similar characteristic or dependence on their pilot pressure.
  • The pressure ranges of the hydraulic system are interconnected by a check valve, wherein the check valve can open the low pressure circuit and the secondary pressure circuit in the direction of the high pressure circuit and the primary pressure circuit. In addition, the pressure relief valve or the first valve unit receives its feedback signal for activating the pressure limiting function from the primary pressure circuit, so that the first valve unit only moves into a Abreglung the excess quantity of the first hydraulic pump when the need of the primary pressure circuit is completely covered by the second hydraulic pump. As long as the first valve unit does not go into the Abregelungsbetriebszustand, all of the funded by the first hydraulic pump hydraulic fluid volume in the first pressure circuit and the primary pressure circuit is initiated. When the primary pressure circuit reaches its full pressure level, the first valve unit moves into the shutdown position. Then, a part of the hydraulic fluid volume delivered by the first hydraulic pump is guided in the direction of the primary pressure circuit, while the other part or the excess quantity is forwarded in the direction of the secondary pressure circuit via the first valve unit. Downstream of the first valve unit, an optional pressure relief valve with a corresponding response limit ensures that the volume of hydraulic fluid supplied in the direction of the secondary pressure circuit is supplied, for example, to the cooling or lubrication of an automatic transmission.
  • The delivery pressure of the first hydraulic pump is in this operating state of the hydraulic system almost at the pressure level of the delivery pressure of the second hydraulic pump. Once the demand of the primary pressure circuit is completely covered by the delivery volume of the second hydraulic pump, the pressure relief valve or the first valve unit is transferred to its end position or its operating state in which the secondary pressure circuit is acted upon by the first hydraulic pump with hydraulic pressure volume. As a result, the pressure level of the secondary pressure circuit drops to the set pressure level of the optional pressure relief valve for cooling and lubrication. This drop in pressure in the secondary pressure circuit in turn causes the check valve means closes the connection between the first hydraulic pump and the primary pressure circuit or between the secondary pressure circuit and the primary pressure circuit and the first hydraulic pump promotes only in the direction of the secondary pressure hydraulic fluid volume, while the primary pressure circuit through the second hydraulic pump is supplied. By reducing the pressure level in the region of the secondary pressure circuit, the pump receiving torque of the first hydraulic pump is reduced abruptly.
  • In their installation position, the two valve units can ideally be arranged close to the respective associated hydraulic pump in order to minimize flow resistances and thus losses of the pump system.
  • In order to be able to reliably ensure the pressure reduction in the secondary pressure circuit, the pressure of the secondary pressure circuit in an embodiment of the hydraulic system according to the invention via the valve is smaller or at least equal to the pressure in the primary pressure circuit.
  • In order to be able to represent a so-called boost function for the non-cycle-relevant area, during which there is an increased volume of hydraulic fluid in the area of the primary pressure circuit, the pressure in the secondary pressure circuit can be varied and adjusted so high that the pressure drop in the secondary pressure circuit is avoided.
  • Both the features specified in the claims and the features specified in the following embodiments of the subject invention are each suitable alone or in any combination with each other to further develop the subject invention.
  • Further advantages and advantageous embodiments of the subject invention result from the claims and the embodiments described in principle below with reference to the drawings.
  • The sole figure of the drawing shows a highly simplified hydraulic schematic of a preferred embodiment of the hydraulic system according to the invention.
  • The figure shows a simplified representation of a hydraulic system 1 an automatic transmission with at least two pressure circuits 2 . 3 , wherein a so-called primary pressure circuit 2 via a valve device 4 with two hydraulic pumps 5 . 6 promoted hydraulic fluid can be supplied with higher priority than a so-called secondary pressure circuit 3 , The delivery volume flow to supply the secondary pressure circuit 3 provided hydraulic pump 6 flows at a positive pressure gradient between the delivery side of the hydraulic pump 6 and the primary pressure circuit 2 at least partially via a check valve device 7 in the direction of the primary pressure circuit 2 and is above a pressure pHD in the primary pressure circuit 2 at least partially via the valve device 4 in the secondary pressure circuit 3 feasible while the connection between the hydraulic pump 6 and the primary pressure circuit 2 at a positive pressure gradient between the primary pressure circuit 2 and the delivery side of the hydraulic pump 6 via the check valve device 7 Is blocked.
  • For this purpose, the valve device 4 a first valve unit 8th and a second valve unit 9 on, at which in each case the pressure pHD of the primary pressure circuit 2 is applied. The pressure pHD of the primary pressure circuit 2 engages the first valve unit 8th against a control force F8 in the direction of a first operating state on the first valve unit 8th in which the hydraulic pump 6 over the first valve unit 8th with the secondary pressure circuit 3 connected is. In addition, the pressure is pHD of the primary pressure circuit 2 at the valve unit 9 against a control force F9 in the direction of an operating state of the valve unit 9 acting applying, in which the hydraulic pump 5 both with the primary pressure circuit 2 as well as with a low pressure area 10 is connected, the present equal to the suction sides of the hydraulic pump 5 and 6 is. The at the valve units 8th and 9 applied control forces F8 and F9 correspond in the present case spring forces of the valve units 8th and 9 attacking spring devices 11 . 12 ,
  • A response limit of the valve unit 8th , starting from the first valve unit 8th from the pressure pHD in the primary pressure circuit 2 is guided in the direction of the first operating state is smaller than a response limit of the valve unit 9 , starting from the valve unit 9 from the pressure pHD in the primary pressure circuit 2 is transferred in the direction of its first operating state.
  • Depending on the particular application, there is also the possibility that the control forces F8 and F9 in the range of spring chambers 13 . 14 the valve units 8th and 9 applied pressure signals result, wherein the control forces can also be generated in each case by a combination of a spring device and a pressure signal.
  • In addition, there is also the possibility that on the valve units 8th and 9 one in each case in the direction of the first operating states of the valve units 8th and 9 acting pressure signal pEDS8 or pEDS9 can be applied to both the response of the valve unit 8th as well as the response of the valve unit 9 in terms of pressure pHD of the primary pressure circuit 2 to change to the desired extent.
  • Downstream of the valve unit 8th and upstream of the secondary pressure circuit 3 is a designed as a constant pressure relief valve or as a variable pressure relief valve 13A provided that above a defined or a variable pressure limit, a connection between the valve unit 8th and the low pressure area 10 manufactures. In an embodiment as a variable pressure relief valve is equivalent to a spring device 15 a pressure signal pEDS13 at the valve 13A Can be applied to the pressure limit or the response of the valve 13A to be able to change.
  • In an operable with little effort embodiment of the hydraulic system according to the invention 1 is at the valve units 8th and 9 and at the valve 13A the same pressure signal can be applied. This means that the pressure signal pEDS8, the pressure signal pEDS9 and the pressure signal pEDS13 correspond to one another and are preferably adjustable in the region of a common electrohydraulic pressure actuator.
  • The following is the operation of the hydraulic system 1 , on the one hand the pressure circuits 2 and 3 Required to be supplied with hydraulic fluid and on the other hand, a pump receiving torque of the hydraulic pumps 5 and 6 is low, explained in more detail with reference to the illustration in the figure:
    Starting from the operating state of the hydraulic system shown in the figure 1 in which both a valve spool 8A the valve unit 8th as well as a valve spool 9A the valve unit 9 from the spring device 11 or of the spring device 12 is shifted to the first end position, promotes both the hydraulic pump 6 as well as the hydraulic pump 5 Hydraulic fluid in the direction of the primary pressure circuit 2 , This results from the fact that each at a return surface 8B respectively. 9B of the valve spool 8A or the valve spool 9A the valve unit 8th respectively. 9 applied pressure pHD in the primary pressure circuit 2 has a level to which a saturation of the primary pressure circuit 2 not reached and all of the hydraulic pumps 5 and 6 provided hydraulic fluid volume in the primary pressure circuit 2 is to be initiated. In this operating state of the hydraulic system 1 lies between the delivery side of the hydraulic pump 6 and the primary pressure circuit 2 a check valve device 7 opening positive pressure gradient before.
  • With increasing delivery volumes of the two hydraulic pumps 5 and 6 the pressure of pHD in the primary pressure circuit rises 2 at. From a defined pressure limit of the pressure pHD of the primary pressure circuit 2 becomes the valve spool 8A the valve unit 8th from that in the area of the control surface 8B applied pressure pHD against the spring force F8 and a force from the pressure signal pEDS8 increasingly shifted from the first end position shown in the figure. This axial adjusting movement of the valve spool 8B causes one with the delivery side of the hydraulic pump 6 connected valve bag 8C over the valve spool 8A with another valve bag 8D is connected, and at least part of the hydraulic pump 6 conveyed hydraulic fluid volume flow through the valve unit 8th in the direction of the secondary pressure circuit 3 to be led.
  • With further increasing pressure pHD of the primary pressure circuit 2 becomes the valve spool 8A increasingly shifted against the spring force F8 and the force from the pressure signal pEDS8. If the pressure reaches pHD of the primary pressure circuit 2 a defined pressure level, to that at the control surface 9B of the valve spool 9A applied pressure pHD the valve spool 9A shifts against the spring force F9 and a force from the pressure signal pEDS9 from the first position shown in the figure, the primary pressure circuit 2 with increasing scope of the hydraulic pump 5 supplied with hydraulic fluid volume.
  • The two valve units 8th and 9 are coordinated so that the valve units 8th from the pressure pHD of the primary pressure circuit 2 only then in a reduction of the excess quantity of the hydraulic pump 6 passes if the need of the primary pressure circuit 2 from the hydraulic pump 5 is covered. That means the valve bag 8C and the valve bag 8D only then be joined together when the pressure pHD of the primary pressure circuit 2 reaches its target pressure level. From this operating condition then becomes part of the flow rate of the hydraulic pump 6 in the direction of the primary pressure circuit 2 promoted while the excess amount in the direction of the secondary pressure circuit 3 over the valve unit 8th to be led. Downstream of the valve unit 8th or the valve bag 8D puts the valve 13A sure that this hydraulic volume of cooling or lubrication of the automatic transmission is performed.
  • The delivery pressure level of the hydraulic pump 6 then corresponds almost to the pressure level of the delivery pressure of the hydraulic pump 5 , Once the need of the primary pressure circuit 2 completely over that of the hydraulic pump 5 funded hydraulic fluid volume is covered, the valve spool 8A against the spring force F8 and the force from the pressure signal pEDS8 transferred to its second fully shifted position, whereby the delivery pressure level of the hydraulic pump 6 to the set pressure level of the valve 13A for the cooling and lubrication of the automatic transmission drops. At the same time closes the check valve device 7 , whereby the primary pressure circuit 2 no longer from the hydraulic pump 6 is supplied with hydraulic fluid volume.
  • With further increasing pressure pHD in the primary pressure circuit 2 will also be the valve spool 9A the valve unit 9 against the spring force F9 and the force shifted from the pressure signal pEDS9, to one with the delivery side of the hydraulic pump 5 connected valve bag 9C with a valve bag 9D communicates with the low pressure area 10 or the suction side of the two hydraulic pumps 5 and 6 is coupled.
  • By reducing the pressure level or the delivery pressure level of the hydraulic pump 6 reduces the pump receiving torque of the hydraulic pump 6 abruptly, so that the automatic transmission can be operated to the desired extent with high efficiency.
  • LIST OF REFERENCE NUMBERS
  • 1
    hydraulic system
    2
    Pressure circuit, primary pressure circuit
    3
    Pressure circuit, secondary pressure circuit
    4
    valve means
    5
    hydraulic pump
    6
    hydraulic pump
    7
    Check valve means
    8th
    valve unit
    8A
    valve slide
    8B
    control surface
    8C, D
    valve pocket
    9
    valve unit
    9A
    valve slide
    9B
    control surface
    9C, D
    valve pocket
    10
    Low pressure area
    11
    spring means
    12
    spring means
    13A
    Valve
    13, 14
    spring chamber
    15
    spring means
    pEDS8
    pressure signal
    pEDS9
    pressure signal
    pEDS13
     pressure signal
    pHD
    Pressure of the primary pressure circuit
  • QUOTES INCLUDE IN THE DESCRIPTION
  • This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
  • Cited patent literature
    • DE 10041386 A1 [0002]

Claims (15)

  1. Hydraulic system ( 1 ) of an automatic transmission with at least two pressure circuits ( 2 . 3 ), wherein a primary pressure circuit ( 2 ) via a valve device ( 4 ) with two hydraulic pumps ( 5 . 6 ) supplied hydraulic fluid with higher priority than a secondary pressure circuit ( 3 ), and wherein the flow rate of the supply to the secondary pressure circuit ( 3 ) provided first hydraulic pump ( 6 ) at a positive pressure gradient between the delivery side of the first hydraulic pump ( 6 ) and the primary pressure circuit ( 2 ) at least partially via a check valve device ( 7 ) in the primary pressure circuit ( 2 ) flows and above a pressure (pHD) in the primary pressure circuit ( 2 ) at least partially via the valve device ( 4 ) in the secondary pressure circuit ( 3 ) is feasible while the connection between the first hydraulic pump ( 6 ) and the primary pressure circuit ( 2 ) at a positive pressure gradient between the primary pressure circuit ( 2 ) and the delivery side of the first hydraulic pump ( 6 ) via the check valve device ( 7 ) is locked, characterized in that the valve device ( 4 ) a first valve unit ( 8th ) and a second valve unit ( 9 ), at which in each case the pressure (pHD) of the primary pressure circuit ( 2 ), wherein the pressure (pHD) of the primary pressure circuit ( 2 ) on the first valve unit ( 8th ) against a control force (F8) in the direction of a first operating state at this attacks, in which the first hydraulic pump ( 6 ) via the first valve unit ( 8th ) with the secondary pressure circuit ( 3 ), while the pressure (pHD) of the primary pressure circuit on the second valve unit ( 9 ) against a control force (F9) in the direction of an operating state of the second valve unit ( 9 ) can be applied effectively, in which the second hydraulic pump ( 5 ) with both the primary pressure circuit ( 2 ) as well as with a low pressure area ( 10 ), wherein a response limit of the first valve unit ( 8th ), from which the first valve unit ( 8th ) from the pressure (pHD) in the primary pressure circuit ( 2 ) is moved in the direction of the first operating state, is smaller than a response limit of the second valve unit ( 9 ), from which the second valve unit ( 9 ) from the pressure (pHD) in the primary pressure circuit ( 2 ) is transferred in the direction of the first operating state.
  2. Hydraulic system according to claim 1, characterized in that on the valve units ( 8th . 9 ) adjoining control forces (F8, F9) at least partially spring forces from at the valve units ( 8th . 9 ) engaging spring devices ( 11 . 12 ) correspond.
  3. Hydraulic system according to claims 1 or 2, characterized in that the control forces applied to the valve units at least partially result from the valve units can be applied to pressures.
  4. Hydraulic system according to one of claims 1 to 3, characterized in that on the valve units ( 8th . 9 ) in each case one opposite to the direction of the first operating states of the valve units ( 8th . 9 ) acting pressure signal (pEDS8, pEDS9) can be applied.
  5. Hydraulic system according to one of claims 1 to 4, characterized in that the valve units are mounted in a bore in series and have the same pressure characteristics.
  6. Hydraulic system according to one of claims 1 to 5, characterized in that the low-pressure region ( 10 ) the suction side of the first hydraulic pump ( 6 ) and / or the second hydraulic pump ( 5 ) corresponds.
  7. Hydraulic system according to one of claims 1 to 6, characterized in that the low-pressure region ( 10 ) is connected to an oil sump of the automatic transmission.
  8. Hydraulic system according to one of claims 1 to 7, characterized in that downstream of the first valve unit ( 8th ) and upstream of the secondary pressure circuit ( 3 ) designed as a constant pressure relief valve or as a variable pressure relief valve ( 13A ) is provided, which above a defined or variable pressure limit, a connection between the first valve unit ( 8th ) and the low pressure area ( 10 ).
  9. Hydraulic system according to claim 8, characterized in that on the valve units ( 8th . 9 ) and the valve ( 13A ) the same pressure signal (pEDS8, pEDS9, pEDS13) can be applied.
  10. Hydraulic system according to one of claims 1 to 9, characterized in that via the first hydraulic pump ( 6 ) at least approximately 70% and via the second hydraulic pump ( 5 ) at least approximately 30% of the total hydraulic system ( 1 ) supplyable hydraulic fluid volume flow is available.
  11. Hydraulic system according to one of claims 1 to 10, characterized in that the hydraulic pumps ( 5 . 6 ) are designed as constant pumps.
  12. Hydraulic system according to one of claims 1 to 11, characterized in that the hydraulic pumps are separate structural units, which have a common drive.
  13. Hydraulic system according to one of claims 1 to 11, characterized in that the hydraulic pumps form a structural unit.
  14. Hydraulic system according to claim 13, characterized in that the hydraulic pumps form a double-vane pump with separate delivery chambers.
  15. Hydraulic system according to claim 14, characterized in that the delivery volumes of the double vane pump are adapted via the contour of a cam ring to the volume requirements of the primary pressure circuit and the secondary pressure circuit.
DE102015212161.5A 2015-06-30 2015-06-30 Hydraulic system of an automatic transmission Pending DE102015212161A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020099026A1 (en) * 2018-11-13 2020-05-22 Zf Friedrichshafen Ag Hydraulic system for an automatic transmission

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2426975A1 (en) * 1973-07-05 1975-01-23 Automobilwerk Eisenach Veb Control valve for foerderpumpen of an automatic transmission for motor vehicles with hydraulic circuit
DE10041386A1 (en) 2000-08-23 2002-03-07 Daimler Chrysler Ag Oil supply optimizing system has at least one regulating disk with at least two waist points
DE102006055182A1 (en) * 2006-11-23 2008-05-29 Daimler Ag Power-split toroid transmission for motor vehicle, has hydraulic system arranged so that actuation pressure of clutch is dependent on number of rotation of shaft in dry-running operation, where number of rotation decreases in sub-region
DE102008009653A1 (en) * 2007-03-07 2008-09-11 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Hydraulic arrangement for controlling a dual-clutch transmission of a motor vehicle
DE102009019959A1 (en) * 2009-05-05 2010-11-11 Daimler Ag A power train assembly
DE102014114965A1 (en) * 2013-12-18 2015-06-18 Hyundai Motor Company Hydraulic pressure supply system of an automatic transmission for a vehicle

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2426975A1 (en) * 1973-07-05 1975-01-23 Automobilwerk Eisenach Veb Control valve for foerderpumpen of an automatic transmission for motor vehicles with hydraulic circuit
DE10041386A1 (en) 2000-08-23 2002-03-07 Daimler Chrysler Ag Oil supply optimizing system has at least one regulating disk with at least two waist points
DE102006055182A1 (en) * 2006-11-23 2008-05-29 Daimler Ag Power-split toroid transmission for motor vehicle, has hydraulic system arranged so that actuation pressure of clutch is dependent on number of rotation of shaft in dry-running operation, where number of rotation decreases in sub-region
DE102008009653A1 (en) * 2007-03-07 2008-09-11 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Hydraulic arrangement for controlling a dual-clutch transmission of a motor vehicle
DE102009019959A1 (en) * 2009-05-05 2010-11-11 Daimler Ag A power train assembly
DE102014114965A1 (en) * 2013-12-18 2015-06-18 Hyundai Motor Company Hydraulic pressure supply system of an automatic transmission for a vehicle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020099026A1 (en) * 2018-11-13 2020-05-22 Zf Friedrichshafen Ag Hydraulic system for an automatic transmission

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