Patent Publication Number: US-2011073428-A1

Title: Non-planar pressurized oil routing

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to British Patent Application No. 0916972.3, filed Sep. 28, 2009, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     This application relates to a clutch actuation device for clutches of a Dual Clutch Transmission. In particular, it relates to a clutch casing with pressurized oil routes for the clutch actuation device. 
     BACKGROUND 
     A Double Clutch Transmission comprises two input shafts that are connected to and are actuated by two clutches separately. The Double Clutch Transmission is also known as Dual Clutch Transmission. The two clutches are often combined into a single device that permits actuating any of the two clutches at a time. The two clutches are connected to two input shafts of the DCT separately for providing driving torques. 
     At least one object of this application is to provide an improved clutch actuation device that is cost efficient. In addition, other objects, desirable features, and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background. 
     SUMMARY 
     The clutch selectively transmits turning motion of an engine to the transmission whilst the transmission transmits the received turning motion to wheels. The engine uses fuel to produce turning motion or mechanical power. The wheels are attached usually to a vehicle that is used in transportation. 
     One of the main thoughts of the application is to provide a device casing with routes for pressurized liquid, such as lubricating oil, is needed to support concentric slave cylinders (CSC) that actuates a clutch release system for a dual clutch transmission. The dual clutch transmission can provide a manual or an automatic transmission. 
     The routes do not intersect or communicate so that the concentric slave cylinders can work independently. Put different, the routes does not allow working liquid or fluid within each route to mix with working liquid in another route. The device casing supports a tight packaging that has space for the clutch release system and space for retention bolts of input shaft bearing. In practice, the working liquid can include gas. The bolts are used for fastening components together. 
     The application provides a device casing or housing for a dual clutch actuation device of an engine transmission. The device casing encloses the clutch actuation device, which is fixed usually to a clutch casing. The device casing encloses parts of the concentric slave cylinders whilst the clutch casing encloses clutches and the clutch actuation device. 
     The dual clutch actuation device includes concentric slave cylinders that comprise an inner chamber and an outer chamber, wherein the outer chamber surrounds either a portion of the inner chamber or the entire inner chamber. The inner chamber and the outer chamber share essentially the same axis. The outer chamber usually has an annular shape. It should be understood that the term “annular”, as used here, refers essentially to a band with an essentially circular shape. The inner chamber can have the annular shape or a cylindrical shape. The inner chamber is used for receiving a working liquid under pressure for actuating a first clutch disc whilst the outer chamber is used for receiving the working liquid under pressure for actuating a second clutch disc. 
     Specifically, the outer chamber surrounds either a portion of the inner chamber or the entire inner chamber. The working liquid can include lubricating oil. The pressure of the liquid is used to actuate the first clutch disc or the second clutch disc. The first clutch disc and the second clutch disc selectively couple or connect an engine to the Dual Clutch Transmission. 
     The device casing includes an internal inner liquid supply passage and an internal outer liquid supply passage. The inner liquid supply passage and the outer liquid supply passage are placed within walls of the device casing or the clutch casing. In other words, they are positioned internal to the device casing or the clutch casing. This reduces space requirement of the device casing as the clutch casing. 
     The internal inner liquid supply passage is intended for connecting to the inner chamber. Put differently, the inner liquid supply passage provides a path so that the working liquid can be introduced to the inner chamber. The inner liquid supply passage comprises a first inner straight section and a second inner straight section, wherein the second inner straight section is intended for connecting to the inner chamber. The first inner straight section and the second inner straight section are connected so that a liquid the first inner straight section can flow to the second inner straight section. 
     In a similar manner, the internal outer liquid supply passage is used for connecting to the outer chamber. The outer liquid supply passage includes a first outer straight section and a second outer straight section. The second outer straight section is intended for connecting to the outer chamber. The first outer straight section and the second outer straight section are connected so that a liquid in the first outer straight section can flows into the second outer straight section. 
     The provision here of two liquid supply passages within the device casing instead of one liquid supply passage has the benefit of enabling the concentric slave cylinders to function correctly. The outer chamber can function independent of the inner chamber. As an example, the outer chamber can receive a clutch actuation oil pressure whilst the inner chamber can receive a lower working oil pressure. 
     Further, the internal inner liquid supply passage can be provided essentially or mostly adjacent to the internal outer liquid supply passage so that the internal inner liquid supply passage does not intersect with the internal outer liquid supply passage. An intersection between the liquid supply passages would cause the inner chamber and the outer chamber to be dependent on each other and thus not work properly. This adjacent placement has the advantages of easier routing design and of easier production of the device casing. 
     The first inner straight section, the second inner straight section, the first outer straight section, and the second outer straight section are formed usually by machining or drilling. The internal inner liquid supply passage and the internal outer liquid supply passage can be provided or be positioned at different levels or heights. The different levels provide a means for the internal inner liquid supply passage and the internal outer liquid supply passage to avoid intersecting with each other. Other means for providing the said avoidance is also possible. The first outer straight section can have an incline or a slight angle relative to the first inner straight section. The incline facilitates passage routing for certain device casing structures such that the respective section does not intersect with each other. 
     The second inner straight section and the second outer straight section can be substantially perpendicular to an axis of the concentric slave cylinders. The perpendicular connection can allow for easier production of the second inner straight section with the inner chamber and easier production of the second outer straight section with the outer chamber. A section or channel seal can block one end of the second inner straight section so that the working liquid does not leak out of the device casing. The first inner straight section can be substantially perpendicular to the second inner straight section for easier production of these said sections. The first outer straight section can be connected to the second outer straight section passage via a connecting straight section. The additional connecting straight section allows easier bypass of the internal inner liquid supply passage. A section or channel seal can block one end of the connecting straight section to prevent leak of working liquid from the device casing. The first outer straight section can be substantially perpendicular to the connecting straight section. The second outer straight section can be substantially perpendicular to the connecting straight section. These said perpendicular connection allows easier alignment for connecting during production of the said connection. 
     The application provides a clutch actuation device for dual clutches of a Dual Clutch Transmission. The dual clutches act as coupling devices between a combustion engine and the Dual Clutch Transmission. The Dual Clutch Transmission comprises gearwheels with teeth around its outer edges for controlling mechanical power from the combustion engine to wheels of a vehicle and for providing speed-changing gears for a user of the vehicle. 
     The clutch actuation device comprises a cylinder assembly that is fixed to the above-mentioned device casing. In particular, the device casing comprises an internal inner liquid supply passage and an internal outer liquid supply passage. The internal inner liquid supply passage and the internal outer liquid supply passage are placed within the device casing. 
     The cylinder assembly includes an inner chamber and an inner piston that is slidably disposed in the inner chamber as well as an outer chamber and an outer piston that is slidably disposed in the outer chamber. The inner chamber is used for receiving liquid under pressure via the inner liquid supply passage. The inner chamber comprises an inner inlet. Likewise, the outer chamber is used for receiving liquid under pressure via the outer liquid supply passage. The outer chamber comprises an outer inlet. Either a portion of the inner chamber or the entire of the inner chamber is surrounded by the outer chamber. The inner piston is used for actuating a first clutch disc whilst the outer piston is intended for actuating a second clutch disc. 
     The clutch actuation device can further comprise an inner piston seal that is fixed to the inner piston and an outer piston seal that is fixed to the outer piston. The inner piston seal and the outer piston seal prevent the liquid within from leaking or keep the liquid within the respective chamber. The clutch actuation device can include a hydraulic circuit that comprises a liquid source, a pump, and an operating valve. The pump is connected to the liquid source and to the operating valve. In particular, the liquid source is positioned usually in a lower part of the Dual Clutch Transmission. The liquid source stores or receives liquid for later use by another component. In application, the liquid source can include a sump. The sump is used for containing liquids in a vehicle. The pump supplies the liquid under pressure from the liquid source to the outer annular chamber via the operating valve and to the inner annular chamber via the operating valve. 
     The operating valve regulates the flow of liquid. The regulation may stop the flow or restrict the flow such that the pressure of the liquid changes. Operationally, the liquid flows through the operating valve selectively engage one of the outer piston and the inner piston as to release the other. The outer piston is disposed in the outer chamber whilst the inner piston is disposed in the inner chamber. Further, the operating valve controls the pressure of the liquid to engage selectively one piston and to release of the other piston. The selected piston can refer to the outer annular piston or to the inner annular piston. The selected chamber receives a clutch actuation pressure for actuating the corresponding selected piston and clutch. 
     The clutch actuation device can also include a pressure relief valve and a conduit means. The conduit means provides liquid passageway and it is connected to a discharge side of the pressure relief valve and to the liquid source. The relief valve maintains a minimum fluid pressure level. The relief valve is arranged with the operating valve such that a predetermined clutch actuation pressure is established in the chamber of the engaged piston whilst a relatively lower pressure is established in the chamber of the unengaged or the disengaged piston. The lower pressure is in reference to the clutch actuation pressure. The lower pressure allows the chamber of the unengaged piston to be filled or be occupied with liquid. 
     The application provides a clutch actuation device for a Dual Clutch Transmission. The clutch actuation device comprises a cylinder assembly that includes a first hydraulic motor and a second hydraulic motor. The first hydraulic motor is used for actuating a first clutch of the Dual Clutch Transmission whilst the second hydraulic motor is used for actuating a second clutch of the Dual Clutch Transmission. In particular, the first hydraulic motor and the second hydraulic motor are arranged such that either a part of the first hydraulic motor or the entire first hydraulic motor is enclosed by the second hydraulic motor. In addition, the cylinder assembly is fixed to the above-mentioned device casing. The small size of the device casing allows the entire clutch actuation device also to have a small size. In some implementation, the first hydraulic motor comprises an inner liquid chamber, wherein an inner piston is disposed in the inner liquid chamber. In a similar manner, the second hydraulic motor also comprises an outer liquid chamber and an outer piston is disposed in the outer liquid chamber. Either a part of the inner chamber or the entire inner chamber is enclosed by the outer chamber. 
     The application provides a Dual clutch Transmission for an engine, such as combustion engine. The Dual clutch Transmission comprises a first clutch disc that is connected to an inner input shaft and one or more input gearwheels that are provided on the inner input shaft. The gearwheels have teeth around its outer edges for controlling mechanical power from a combustion engine to one or more wheels of a vehicle. The first clutch disc is used for selectively connecting the inner input shaft to the combustion engine. The input gearwheels are connected or engaged to output gearwheels that are placed on an output shaft. 
     Furthermore, the Dual clutch Transmission includes a second clutch disc that is connected to an outer input shaft and one or more input gearwheels that are provided on the outer input shaft. The second clutch disc is used for selectively connecting the outer input shaft to the combustion engine. The inner input shaft and the outer input shaft are arranged such that either a portion of or the entire the inner input shaft is surrounded by the outer input shaft. The above clutch actuation device selectively actuates the first clutch disc and the second clutch disc to engage a combustion engine. In practice, turning motions of the combustion engine is transmitted via either the inner or the outer input shaft to the input gearwheels, to the output gearwheels, to the output shaft, and to one or wheels of a vehicle. 
     The application provides a powertrain and a vehicle with the power train. The powertrain is used for transmitting mechanical power to one or more wheels of the vehicle. The powertrain includes an internal combustion engine and the above-mentioned Dual Clutch Transmission. The Dual Clutch Transmission is engageable or is connectable to the internal combustion engine. The vehicle includes the powertrain and one or more wheels that are selectively connected to the powertrain. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and. 
         FIG. 1  illustrates a three-dimensional cross-sectional view of an embodiment of a clutch actuation device; 
         FIG. 2  illustrates a two-dimensional view cross-sectional of the clutch actuation device of  FIG. 1 ; 
         FIG. 3  illustrates a schematic view of a hydraulic system for operating the clutch actuation device of  FIG. 1  and  FIG. 2 ; 
         FIG. 4  illustrates a front view of a clutch casing of the clutch actuation device of  FIG. 1 ; 
         FIG. 5  illustrates a perspective view of the clutch actuation device of  FIG. 4 ; 
         FIG. 6  illustrates a transparent view of another embodiment of a clutch actuation device; 
         FIG. 7  illustrates a perspective view of the clutch actuation device of  FIG. 6 ; 
         FIG. 8  illustrates a sectional view of the clutch actuation device of  FIG. 6 ; 
         FIG. 9  illustrates a first oil supply path of the clutch actuation device of  FIG. 6 ; 
         FIG. 10  illustrates a second oil supply path of the clutch actuation device of  FIG. 6 ; 
         FIG. 11  illustrates an exposed view of oil passages of the clutch actuation device of  FIG. 6 ; and 
         FIG. 12  illustrates a transparent view of the clutch actuation device of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description. 
       FIG. 1  and  FIG. 2  depict cross-sectional views of a device  10  for actuating dual clutches of a Dual Clutch Transmission. The dual clutches allow a turning force from a combustion engine to be sent to a powertrain or to wheels of a vehicle. The Dual Clutch Transmission has gears that comprise wheels with teeth around outer edges of the wheels for controlling mechanical power from the combustion engine to the powertrain or to the wheels of the vehicle. The vehicle provides a means of transport. 
     A control member  57 , as shown in  FIG. 3 , actuates the clutch actuation device  10  for engaging or for acting on a first clutch release device  18  and a second clutch release device  19 . The term “acting” is also called “bearing”. In particular, the drive member  14  is adapted to operate on clutch release devices  18  and  19 , when the maneuvering member  13  acts or urges on the drive member  14  in the axial direction. The maneuvering member  13  is adapted for engaging or for acting by the control member  57 . 
     The clutch actuation device  10  comprises a maneuvering member  13  and a drive member  14 . The maneuvering member  13  is placed towards a gearbox side of the vehicle whilst the drive member  14  is placed towards a motor or a clutch side of the vehicle. The gearbox is also known as transmission casing. The motor is also known as combustion engine. 
     Referring to the maneuvering member  13 , the maneuvering member  13  comprises a concentric slave cylinders assembly  21  with a set of pistons. The concentric slave cylinders assembly  21  is fixed or is secured to a clutch casing  16  or housing of the dual clutches. The clutch casing  16  encloses inner parts of the dual clutches and the concentric slave cylinders assembly  21 . The concentric arrangement of the slave cylinders assembly  21  allows the clutch actuation device  10  to be implemented with less space as compared to other implementation arrangement or design. 
     The slave cylinders assembly  21  includes a first cylinder  23 , a second cylinder  24 , and a third cylinder  25 . These cylinders  23 ,  24 , and  25  share a same axis. The first cylinder  23  surrounds the second cylinder  24  as well as the third cylinder  25  whilst the second cylinder  24  surrounds the third cylinder  25 . An outer annular piston  27  is disposed slidably between the first cylinder  23  and the second cylinder  24 . The outer annular piston  27  has a first end and a second end. The first end is directed towards the gearbox side whilst the second end is directed towards the clutches side. 
     The first end of the outer annular piston  27  together with the first cylinder  23  and the second cylinder  24  form an outer annular chamber  30 . The outer annular chamber  30  has an outer inlet  31 . The first end of the outer annular piston  27  also forms essentially a hermetic seal with the first cylinder  23  and with the second cylinder  24  such that any liquid in the outer annular chamber  30  does not leak towards the second end of the outer annular piston  27 . In a special embodiment, the hermetic seal is achieved by providing the first end of the outer annular piston  27  with a rubber seal. Further, the second end of the annular piston  27  is adapted for engaging or for acting on the drive member  14 . Similarly, an inner annular piston  33  is disposed slidably between the second cylinder  24  and the third cylinder  25 . The inner annular piston  33  has a first end and a second end. The first end is directed towards the gearbox side whilst the second end is directed towards the clutches side. 
     The first end of the inner annular piston  33  together the second cylinder  24  and the third cylinder  25  form an inner annular chamber  34 . The inner annular chamber  34  has an inner inlet  35 . The first end of the inner annular piston  33  also forms essentially a hermetic seal with the second cylinder  24  and with the third cylinder  25  such that any liquid in the inner annular chamber  34  does not leak to the second end of the inner annular piston  33 . In an alternative embodiment, the hermetic seal is achieved by placing a rubber seal on the inner annular piston  33 . Moreover, the second end of the inner annular piston  33  is adapted for engaging or for acting on the drive member  14 . Further, the outer annular piston  27  surrounds the inner annular piston  33  such that the outer annular piston  27  and the inner annular piston  33  share the same axis. Likewise, the outer annular chamber  30  surrounds the inner annular chamber  34  so that the outer annular chamber  30  and the inner annular chamber  34  share the same axis. In a generic sense, the inner annular piston  33  and the second annular chamber  24  functions as part of a hydraulic motor. The outer annular piston  27  and the outer annular chamber  30  also functions as part of a hydraulic motor. 
     Referring to the drive member  14 , the drive member  14  includes a first clutch bearing  36  and a second clutch bearing  37 . The clutch bearings  36  and  37  are also known as clutch release bearings. The first clutch bearing  36  includes a ball bearing  40  and two generally annular members. The annular members comprises an inside ring  41  and an outside ring  42  that together encloses the ball bearing  40 . A deflector  44  is placed between one end of the inside ring  41  and one end of the outside ring  42 . The outside ring  42  is adapted for engaging or for acting by the second end of the outer annular piston  27  of  FIG. 2 . The inside ring  41  is adapted to bear on the clutch release device  18 , when the outside ring  42  is acted on by the outer annular piston  27 . 
     In a similar manner, the second clutch bearing  37  comprises a ball bearing  46 , an inside ring  47  and an outside ring  48 . The inside ring  47  and the outside ring  48  surrounds the ball bearing  46 . A deflector  50  is positioned between one end of the inside ring  47  and one end of the outside ring  48 . The outside ring  48  is adapted for engaging or for acting by the second end of the inner annular piston  33  of  FIG. 2 . The inside ring  47  is adapted to bear on the clutch release device  19 , when the outside ring  48  is acted on by the inner annular piston  33 . Moreover, the ball bearings  40  and  46  each comprises a ball cage, which is not shown, for retaining or keeping the ball bearings  40  and  46  in position. Lubricating grease is employed on the ball bearings  40  and  46  to ensure its anti-friction characteristic. 
       FIG. 3  shows a schematic view of a hydraulic system  55  for operating the clutch actuation device  10  of  FIG. 1  and  FIG. 2 . The hydraulic system  55  does not include levers. The hydraulic system  55  includes a control member  57 . The control member  57  includes a gear pump  66  for controlling or for actuating the clutch actuation device  10  using an operating valve  72  and a relief valve  74 . Specifically, the control member  57  comprises a sump  58 . The sump  58  is disposed in a lower portion of a transmission casing or housing. A first conduit  101  connects a sump outlet  60  to a filter inlet  61  whilst a second conduit  102  connects a filter outlet  63  to an inlet  64  of the gear pump  66 . A third conduit  103  connects a gear pump outlet  68  to an inlet  70  of the operating valve  72  and to an inlet  73  of the relief valve  74 . 
     A fourth conduit  104  connects a first operating valve outlet  76  to the outer inlet  31  of the outer annular chamber  30  whilst a fifth conduit  105  connects a second operating valve outlet  77  to the inner inlet  35  of the inner annular chamber  34  of the slave cylinders assembly  21 . A sixth conduit  106  connects a relief valve outlet  80  to an operating valve inlet  81  and to an inlet  84  of a cooler  85 . A seventh conduit  107  connects a cooler outlet  87  to a sump inlet  90 . 
     In practice, the sump  58  contains or holds a working liquid, which usually is in the form of lubricating oil. The working liquid provides a medium for transmitting clutch actuation pressure to the clutch actuation device  10 . The outer inlet  31  of the outer annular chamber  30  and the inner inlet  35  of the inner annular chamber  34  of the clutch actuation device  10  of  FIG. 1  and  FIG. 2  receive the clutch actuation pressure. 
     The lubricating oil is drawn from the sump  58  through the filter  62  by the gear pump  66  and it is forced under pressure through the relief valve  74  and through the operating valve  72  to the clutch actuation device  10 . The filter  62  removes contaminants or foreign particles from the working liquid to keep these contaminants from reaching the relief valve  74  and the operating value  72 . 
     The relief valve  74  is arranged or configured such that the relief valve  74  allows a relatively low pressure, for example, about five pounds per square inch, to be applied or transmitted to the clutch actuation device  10 . This insures that the annular chambers  30  and  34  are filled constantly with the lubricating oil. The constant filling compensates for any leakage and allows for a rapid increase in the pressure of the lubrication oil in either outer annular chamber  30  or inner annular chamber  34  upon movement or activation of pressure by the operating valve  72 . 
     When the Dual Clutch Transmission is in a neutral state, the operating valve  72  is also arranged to be in a neutral state. The neutral state is also called a neutral position. In the neutral state, the operating valve  72  does not transmit a pressure to the clutch actuation device  10 . In this state, the clutches of the Dual Clutch Transmission are not engaged. In a case of a vehicle that has the Dual Clutch Transmission, a combustion engine of the vehicle is not connected to powertrain or to wheels of the vehicle, since the clutches are not engaged. 
     If a forward or a reverse gear of the Dual Clutch Transmission is selected, the pressure from the operating valve  72  is increased to actuate the appropriate clutch that corresponds to the selected gear. The selected gear relates to a particular gear ratio of the Dual Clutch Transmission. One gear would correspond to only one clutch of the dual clutches of the Dual Clutch Transmission. In most implementation, the forward gear of an odd number relates to one clutch of the dual clutches whilst the forward gear of an even number relates to the other clutch of the dual clutches. 
     The actuation of the clutch is achieved by transmitting the actuating clutch pressure from the gear pump  66 , to the appropriate outlet  76  or  77  of the operating valve  72  via the lubricating oil. The actuating clutch pressure is also transmitted to the corresponding annular chamber  30  or  34 . The corresponding annular chamber  30  or  34  experiences an increased rapidly pressure to the actuating clutch pressure of, for example, about one hundred pounds per square inch, while pressure of the other non-selected annular chamber  30  or  34  remains the low pressure of about five pounds per square inch. 
     The clutch actuation pressure is then exerted on the corresponding annular piston  27  or  33 . This pressure actuates or moves the corresponding annular piston  27  or  33  to bear on the corresponding clutch bearing  36  or  37 , and thus on the corresponding clutch release device  18  or  19  for engaging the appropriate selected clutch. If the clutch actuation pressure is removed or is reduced from the annular chamber  30  or  34 , the corresponding clutch of the dual clutches is also released. Lubricating oil that does not reach the clutch actuation device  10  is passed through the cooler  85  en route to the sump  58 , thus completing the cycle. 
     In a generic sense, the embodiment can include a coupling means to provide an appropriate axial linkage between the drive member  14  and the maneuvering member  13 . Moreover, the outer annular piston  27  can comprise a transverse flange, which may be a simple collar, for engaging or for bearing on the first clutch bearing  36 . The first clutch bearing  36  can comprise a radial rim and an axially acting annular spring. The axially acting annular spring is intended for engaging or for bearing on the radial rim to urge the radial rim towards the transverse flange of outer annular piston  27  in an axial direction. In this manner, the first clutch bearing  36  is retained axially or is secured relative to the outer annular piston  27 . 
     Similarly, the inner annular piston  33  can comprise a transverse flange for engaging or for bearing on the second clutch bearing  37 . The second clutch bearing  37  can also include a radial rim and an axially acting annular spring. The axially acting annular spring is intended for engaging or for bearing on the radial rim to urge the radial rim towards the transverse flange of inner annular piston  33  in an axial direction. In this way, the second clutch bearing  37  is retained axially relative to the inner annular piston  33 . 
     In short words, the concentric slave cylinders assembly  21  actuates the two clutches of a Dual Clutch Transmission using a hydraulic system. The concentric slave cylinders assembly  21  is located in the clutch casing  16  as well as being fixed to the clutch casing  16 . Each annular piston  27  or  33  of the slave cylinders assembly  21  applies or actuates the two clutches and release the two clutches through the application or release of bearings  36  and  37 . Working liquid under adequate pressure is injected into the annular chambers  30  and  34  of the concentric slave cylinders assembly  21 . 
     This embodiment operates the clutches in an innovative manner and requires less space in comparison with other piston actuation implementation. The embodiment also avoids usage of levers to actuate the clutches. 
       FIG. 4  depicts a front view of the clutch casing  16  of the clutch actuation device  10  of  FIG. 1 . The clutch casing  16  has attachment points  110  and  111 , bearing plate points  113 ,  114 , and  115 , and a travel sensor  117 . The attachment points  110  and  111 , the bearing plate points  113 ,  114  and  115 , together with the travel sensor  117  are placed next to the clutch actuation device  10 . The clutch case clearance geometry is as indicated in the  FIG. 4 . 
     Functionally, the attachment points  110  and  111  are intended for the connected the clutch casing  16  to a gearbox casing of a transmission. The attachment points  110  and  111  have bolt openings or holes to secure the clutch casing  16  to the gearbox casing. The clutch-side bolt openings are formed at a lower side of the clutch casing  16  and are formed with internal threads to threadably engage setting bolts. The setting bolts can have screw-like metal objects that are used to fasten components together. 
     The bearing plate points  113 ,  114 , and  115  are used for attaching a bearing retainer plate of the clutch casing  16  that is placed internally in the transmission. The bearing retainer plate is intended for supporting reaction loads form gears or gearwheels of the transmission. The travel sensor  117  is intended for indicating position of a clutch disc. 
       FIG. 5  shows a perspective view of a device casing  118  of the clutch actuation device  10  of  FIG. 4 . The device casing  118  encloses parts of the concentric slave cylinders assembly  21  with a set of pistons of  FIG. 1 . The clutch actuation device  10  has a device casing or housing that comprises a first passageway and a second passageway. The first passageway provides a working liquid to the inner annular chamber  34  whilst the second passageway provides a working liquid to the outer annular chamber  30  such that both passageways do not intersect with each other even though both passageways may be placed adjacent to each other. 
     Within the device casing  118  of the clutch actuation device  10  is formed an inner liquid supply passage  120  and an outer liquid supply passage  121 . The inner liquid supply passage  120  is used to provide a working liquid to the inner annular chamber  34  whilst the outer liquid supply passage  121  is used to provide a working liquid to the outer annular chamber  30 . The inner liquid supply passage  120  does not intersect with the outer liquid supply passage  121  even though the inner liquid supply passage  120  is provided adjacent to the outer liquid supply passage  121 . A portion of the outer liquid supply passage  121  has an incline relative to the inner liquid supply passage  120  for avoiding the said intersection. 
     The inner liquid supply passage  120  comprises a first inner supply channel  123  and a second inner supply channel  124 , which are extending essentially in a linear manner and are provided essentially in a same plane. The first inner supply channel  123  and the second inner supply channel  124  have an essentially longish or straight profile. One end of the first inner supply channel  123  is connected to a central portion of the second inner supply channel  124  so that a liquid in the first inner supply channel  123  can flow into the second inner supply channel  124 . 
     The first inner supply channel  123  has a first end and a second end. The first end is placed at a front opening  126  at a front  127  of the device casing  118  of the clutch actuation device  10  whilst the second end is provided at an internal part  129  of the device casing  118  of the clutch actuation device  10 . In contrast, the second inner supply channel  124  has a first end and a second end, wherein the first end is positioned at a first side opening  131  at a side  132  of the device casing  118  of the clutch actuation device  10  and the second end is provided at the inner inlet  35  of the inner annular chamber  34 . A first channel seal  133  later covers the first side opening  131 . A central portion of the second inner supply channel  124  is joined to the second end of the first inner supply channel  123  so that a liquid in the second inner supply channel  124  can flow into the first inner supply channel  123 . 
     The outer liquid supply passage  121  comprises a first outer supply channel  137 , a second outer supply channel  138  and a connecting outer channel  139  that connects the first outer supply channel  137  to the second outer supply channel  138 . The connection allows a liquid in the first outer supply channel  137  to flow to the second outer supply channel  138  via the connecting outer channel  139 . The first outer supply channel  137 , the second outer supply channel  138  and the connecting outer channel  139  extend essentially in a linear manner. The first outer supply channel  137 , the second outer supply channel  138  and the connecting outer channel  139  have an essentially longish or straight profile. In addition, the first outer supply channel  137  has a first end and a second end. The first end is placed at a bottom opening  140  at a bottom  141  of the device casing  118  of the clutch activation device  10  whilst the second end is provided at an internal part of the device casing  118  of the clutch actuation device  10 . 
     In contrast, the second outer supply channel  138  has a first end and a second end, wherein the first end is positioned at a second side opening  143  at the side  132  of the device casing  118  of the clutch actuation device  10  and the second end is provided at the outer inlet  31  of the outer annular chamber  30 . During operations, a second channel seal  145  later covers the second side opening  143 . 
     The second end of the first outer supply channel  137  is joined to a first end of the connecting outer channel  139  whilst a central portion of the second outer supply channel  138  is joined to a second end portion of the connecting outer channel  139 . The second end portion of the connection outer channel  139  is also connected an opening at the bottom of the device casing  118  of the clutch activation device  10 . The opening is closed or is blocked by a channel seal  147 . The arrangement allows a liquid in the first outer supply channel  137  to flow to the second outer supply channel  138  via the connecting outer channel  139 . 
     Comparing the inner liquid supply passage  120  to the outer liquid supply passage  121 , the first inner supply channel  123  is provided adjacent to the first outer supply channel  137 . Moreover, the first inner supply channel  123  is not parallel to the first outer supply channel  137  and is at an incline relative to the first outer supply channel  137 . The second inner supply channel  124  is placed adjacent to the second outer supply channel  138 . The second inner supply channel  124  and the second outer supply channel  138  are positioned essentially in a same plane. 
     In one embodiment, the first inner supply channel  123  and the second inner supply channel  124  of the inner liquid supply passage  120  are formed by machining or by drilling. Then one end of the second inner supply channel  124  is blocked with the first channel seal  133 . The drilling provides the essentially longish profile. Similarly, the first outer supply channel  137 , the second outer supply channel  138  and the connecting outer channel  139  of the outer liquid supply passage  121  are formed by drilling. The second channel seal  145  afterward blocks one end of the second outer supply channel  138 . 
     The above-mentioned incline advantageously enables the first inner supply channel  123  and the second inner supply channel  124  not to intersect with the first outer supply channel  137  and not to intersect with the second outer supply channel  138 . Without the incline or positioning of the supply channels  124  and  137  at different levels, the said intersection would occur and thus preventing the clutch actuation device  10  from working properly. 
     Functionally, the first inner supply channel  123  and the second inner supply channel  124  provide a passageway for a working liquid to the inner annular chamber  34 . The front opening  126  enables the working liquid to be introduced to the inner annular chamber  34 . The first channel seal  133  blocks first side opening  131  such that the working liquid does not leak or flow out of the device casing  118  of the clutch actuation device  10 . 
     Similarly, the first outer supply channel  137 , the second outer supply channel  138  and the connecting outer channel  139  provide a passageway for a working liquid to the outer annular chamber  30 . The bottom opening  140  allows the working liquid to be introduced to the first outer supply channel  137 . The second channel seal  145  blocks the second side opening  143  such that the working liquid does not leak or flow out of the device casing  118  of the clutch actuation device  10 . In a similar manner, the channel seal  147  blocks one end of the connecting outer channel  139  so that the working liquid does not leak or flow out of the device casing  118  of the clutch actuation device  10 . 
     In a similar manner, the second opening of the first outer supply channel is used for introducing the working liquid that is pressured by the pump  66  to the outer chamber via the second end of the first outer supply channel and via the second end of the second outer supply channel. The channel seal blocks the first end of the second outer supply channel so that the working liquid does flow out of the device casing  118 . 
       FIG. 6  shows a transparent view of another embodiment of a clutch actuation device  150 . The  FIG. 6  shows a way of providing oil passageways to the clutch actuation device  150 . For better illustration of the embodiment,  FIG. 7  shows a solid perspective view of the clutch actuation device  150 . Similarly,  FIG. 8  shows a sectional view of the clutch actuation device  150 . 
     The clutch actuation device  150  and the clutch actuation device  10  of  FIG. 1  have similar parts. The similar parts have similar names or same part numbers. The description of the similar parts is hereby incorporated by reference.  FIG. 6  shows a device casing  152  of the clutch actuation device  150 . The device casing  152  encloses parts of a concentric slave cylinders assembly. 
     Internally within the device casing  152 , is formed the inner liquid supply passage  120  and the outer liquid supply passage  121 . The inner liquid supply passage  120  does not intersect with the outer liquid supply passage  121  even though the inner liquid supply passage  120  is provided adjacent to the outer liquid supply passage  121 . The inner liquid supply passage  120  is intended for introducing a working liquid to the inner annular chamber  34  whilst the outer liquid supply passage  121  is intended for introducing a working liquid to the outer annular chamber  30 . 
     Further, the outer liquid supply passage  121  and the inner liquid supply passage  120  are positioned at different levels or heights. The difference in levels advantageously allows the liquid supply passages  120  and  121  to be adjacent to each other but yet without intersecting each other. An intersection of the said liquid supply passages  120  and  121  would prevent the clutch actuation device  150  from operating properly. 
     Structurally, the parts of the inner liquid supply passage  120  and the outer liquid supply passage  121  are described above, wherein the both supply passages  120  and  121 , as provided here, are essentially parallel to each other. In addition, the inner liquid supply passage  120  is connected to a bottom opening  154  of the device casing  152  via a vertical connection channel  156 . The working liquid is fed to the inner liquid supply passage  120  via the bottom opening  154  to the vertical connection channel  156 . Similarly, the outer liquid supply passage  121  is connected to the bottom opening  140  of the device casing  152  a vertical connection channel  158 . The working liquid is fed to the outer liquid supply passage  121  via the bottom opening  140  to the vertical connection channel  158 . 
       FIG. 9  shows a first oil supply path or route  160  of the clutch actuation device  150  of  FIG. 6 . The oil supply path  160  provides a passageway for feeding or introducing the working liquid to the outer annular chamber  30 . The oil supply path  160  extends from the bottom opening  140 , via the vertical connection channel  156 , via the first outer supply channel  137 , via the connecting outer channel  139 , and via the second outer supply channel  138  to the outer annular chamber  30 . 
     In a similar manner,  FIG. 10  shows a second oil supply path  162  of the clutch actuation device  150  of  FIG. 6 . The oil supply path  162  provides a way for feeding or introducing the work liquid to the inner annular chamber  34 . The oil supply path  162  extends from the bottom opening  154 , via the vertical connection channel  156 , via the first inner supply channel  123 , and via the second inner supply channel  124  to the inner annular chamber  34 . 
     Comparing  FIG. 9  and  FIG. 10 , the first oil supply path  160  is positioned above the oil supply path  162 . In addition, the oil supply path  160  is not at an incline or at an angle relative to the oil supply path  162 . Put differently, the oil supply paths  160  and  162  are provided at different levels or heights, wherein the oil supply paths  160  and  162  are essentially parallel to each other. This difference of level allows the oil supply paths  160  and  162  not to intersect each other even though they are placed near each other. 
     For easier illustration of the embodiments,  FIG. 11  shows an exposed view of the oil passages of the clutch actuation device  150  of  FIG. 6 .  FIG. 12  shows a transparent or an outline view of the clutch actuation device  150  of  FIG. 6 . 
     Although the above description contains much specificity, these should not be construed as limiting the scope of the embodiments but merely providing illustration of the foreseeable embodiments. Especially the above stated advantages of the embodiments should not be construed as limiting the scope of the embodiments but merely to explain possible achievements if the described embodiments are put into practice. Moreover, while at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.