Abstract:
A torque transmitting assembly includes an actuator for engaging a torque transmitting element. A mechanism is connected to the actuator. The mechanism is operable to selectively allow fluid communication therethrough. The mechanism communicates between two separate fluid spaces located on opposite sides of the actuator. During movement of the actuator, a fluid is allowed to transfer through the mechanism between the two separate fluid spaces.

Description:
FIELD 
       [0001]    The invention relates generally to a clutch assembly, and more particularly to a multi-area clutch assembly having a quick fill mechanism. 
       BACKGROUND 
       [0002]    The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
         [0003]    A typical multi-speed automatic transmission uses a combination of torque transmitting devices, such as clutches, dog clutches/synchronizers, or brakes, to achieve a plurality of forward and reverse gear or speed ratios as well as a Neutral and a Park. Selection of speed ratios is typically accomplished by a microprocessor transmission control module that employs various vehicle parameters, for example vehicle speed, and various driver input signals, for example accelerator pedal position, to select the appropriate speed ratios. The transmission then engages a combination of the toque transmitting devices to provide the desired speed ratios. 
         [0004]    In order to engage the torque transmitting devices, a typical automatic transmission includes a hydraulic clutch control system that employs a hydraulic fluid to selectively actuate pistons within the torque transmitting devices. Actuation of a piston in turn engages the torque transmitting elements within the torque transmitting device. One piston design, known as a dual-area piston, includes two areas located on the piston that are hydraulically isolated from one another. One area is pressurized by the hydraulic fluid from the hydraulic clutch control system in order to stroke the piston. The non-pressurized area is typically connected to an exhaust backfill circuit to help prevent the creation of a vacuum within the non-pressurized area as the piston strokes. However, if the exhaust backfill circuit is unable to adequately provide a fluid to fill the non-pressurized area, issues with fluid pressure control and air entrainment may arise. Accordingly, there is a need in the art for a multi-area clutch assembly that is designed to minimize the creation of a vacuum in the non-pressurized area to thereby improve pressure control and prevent air entrainment, and that is also inexpensive and automatic. 
       SUMMARY 
       [0005]    The present invention provides a torque transmitting assembly that includes an actuator for engaging a torque transmitting element. A mechanism is connected to the actuator. The mechanism is operable to selectively allow fluid communication therethrough. The mechanism communicates between two separate fluid spaces located on opposite sides of the actuator. During movement of the actuator, a fluid is allowed to transfer through the mechanism between the two separate fluid spaces. 
         [0006]    An embodiment of the torque transmitting assembly of the present invention includes a housing that defines a cavity, an actuator slidably disposed within the cavity of the housing, wherein the actuator includes a first surface that cooperates with the housing to define a first space, a second surface that cooperates with the housing to define a second space, and a third surface that cooperates with the housing to define a third space, wherein the third space is located on a side of the actuator opposite the first and second spaces, and wherein a fluid is located within the third space, a torque transmitting element interconnected to the housing that is selectively engageable by the actuator, and a mechanism connected to the actuator for selectively communicating the fluid located in the third space between the third space and the first space. The torque transmitting element is engaged by the actuator when a pressurized fluid enters the second space and contacts the second surface of the actuator to move the actuator towards the torque transmitting element, and wherein the fluid within the third space communicates through the mechanism into the first space as the actuator moves. 
         [0007]    In one aspect of the present invention, the mechanism is a valve. 
         [0008]    In another aspect of the present invention, the mechanism is at least one of a ball valve and a check valve. 
         [0009]    In yet another aspect of the present invention, the mechanism permits the fluid to flow in only one direction through the mechanism. 
         [0010]    In yet another aspect of the present invention, the mechanism permits the fluid to pass through the mechanism when a pressure of the fluid in the third space exceeds a threshold value. 
         [0011]    In yet another aspect of the present invention, a plurality of mechanisms are located in the actuator and are located equidistant apart from one another. 
         [0012]    In yet another aspect of the present invention, the first space is hydraulically isolated from the second space. 
         [0013]    In yet another aspect of the present invention, the third space is hydraulically isolated from the first space and the second space. 
         [0014]    In yet another aspect of the present invention, a biasing member is located within the third space and is in contact with the actuator to bias the actuator away from the torque transmitting element. 
         [0015]    Another embodiment of the torque transmitting assembly of the present invention includes a housing that defines a cavity, an actuator slidably disposed within the cavity of the housing, wherein the actuator includes a first surface that cooperates with the housing to define a first space, a second surface that cooperates with the housing to define a second space, and a third surface that cooperates with the housing to define a third space, wherein the third space is located on a side of the actuator opposite the first and second spaces, and wherein a fluid is located within the third space, a torque transmitting element interconnected to the housing that is selectively engageable by the actuator, a mechanism connected to the actuator for selectively communicating the fluid located in the third space between the third space and the first space, a first fluid passage in communication with the first space and the third space, and a second fluid passage in communication with the second space. The torque transmitting element is engaged by the actuator when a pressurized fluid is communicated by the second fluid passage to the second space and the pressurized fluid contacts the second surface of the actuator to move the actuator towards the torque transmitting element, and wherein the fluid within the third space communicates through the mechanism into the first space and the fluid within the third space communicates through the first fluid passage to the first space as the actuator moves. 
         [0016]    In one aspect of the present invention, a valve assembly is in communication with the second fluid passage for selectively communicating the pressurized fluid into the second fluid passage. 
         [0017]    In another aspect of the present invention, the mechanism is a valve. 
         [0018]    In yet another aspect of the present invention, the mechanism is at least one of a ball valve and a check valve. 
         [0019]    In yet another aspect of the present invention, the mechanism permits the fluid to flow in only one direction through the mechanism. 
         [0020]    In yet another aspect of the present invention, the mechanism permits the fluid to pass through the mechanism when a pressure of the fluid in the third space exceeds a threshold value. 
         [0021]    In yet another aspect of the present invention, a plurality of mechanisms are located in the actuator, wherein the mechanisms are located equidistant apart from one another. 
         [0022]    In yet another aspect of the present invention, the first space is hydraulically isolated from the second space. 
         [0023]    In yet another aspect of the present invention, the third space is hydraulically isolated from the first space and the second space. 
         [0024]    In yet another aspect of the present invention, a biasing member is located within the third space and is in contact with the actuator to bias the actuator away from the torque transmitting element. 
         [0025]    Still another embodiment of the torque transmitting assembly of the present invention includes a housing that defines a cavity, an actuator slidably disposed within the cavity of the housing, wherein the actuator includes a first surface and a second surface, wherein the first surface cooperates with the housing to define a first space and a second space, and the second surface cooperates with the housing to define a third space, wherein the third space is located on a side of the actuator opposite the first and second spaces, and wherein the first space is hydraulically isolated from the second space, a fluid located within the third space, a torque transmitting element interconnected to the housing that is selectively engageable by the actuator, and a mechanism having a first port in fluid communication with the first space and a second port in fluid communication with the third space, wherein the mechanism is operable to selectively allow fluid communication between the first port and the second port. The torque transmitting element is engaged by the actuator when a pressurized fluid enters the second space and contacts the second surface of the actuator to move the actuator towards the torque transmitting element, and wherein movement of the actuator towards the torque transmitting element allows fluid communication between the first port and the second port and the fluid within the third space communicates through the first port and the second port to the first space. 
         [0026]    Further objects, aspects and advantages of the present invention will become apparent by reference to the following description and appended drawings wherein like reference numbers refer to the same component, element or feature. 
     
    
     
       DRAWINGS 
         [0027]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0028]      FIG. 1  is a diagrammatic cross-sectional view of a portion of an embodiment of a multi-area clutch assembly and hydraulic control system according to the principles of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0030]    With reference to  FIG. 1 , a top-half of a multi-area clutch assembly or torque transmitting assembly is generally indicated by reference number  10 . The multi-area clutch assembly  10  is employed in the present embodiment within a transmission (not shown) of a motor vehicle. The multi-area clutch assembly  10  may be either a stationary clutch assembly or a rotating clutch assembly without departing from the scope of the present invention. The multi-area clutch assembly  10  generally includes a housing  12 , a hub  14 , a clutch pack  16 , an actuator  18 , and a quick fill mechanism  19 . The housing  12  is preferably annular and includes an inner surface  20  and a backing plate  21 . The inner surface  20  and the backing plate cooperate to define a central space or cavity  22  within the housing  12 . The housing  12  may be coupled to various components within the transmission, such as, for example, gear sets, a torque converter, shafts or coupling members, or a ground such as a transmission housing or other fixed component. 
         [0031]    The hub  14  is preferably annular and includes an end portion  24  located radially inward of the housing  12 . The hub  14  may be coupled to various components within the transmission, such as, for example, gear sets, a torque converter, shafts or coupling members, or a ground such as a transmission housing or other fixed component. The hub  14  and housing  12  are rotatable with respect to one another. 
         [0032]    The clutch pack  16  is located radially inward of the housing  12  and includes a first set of reaction discs  26  interleaved with a second set of reaction discs  28 . The reaction discs  26 ,  28  may take various forms, such as, for example, opposing steel discs and fiber faced discs. The first set of reaction discs  26  include an outer radial surface  30  coupled to a spline  32  located in the inner surface  20  of the housing  12 . The second set of reaction discs  28  include an inner radial surface  34  coupled to a spline  36  located in the end portion  24  of the hub  14 . The reaction discs  26 ,  28  are moveable in an axial direction along the splines  32 ,  36 , as will be described in greater detail below. 
         [0033]    The actuator  18  is slidably disposed within the central cavity  22  and includes a piston arm  37 , a radial outer end  38 , a radial inner end  39 , and a radially extending portion  43  that has a first surface or dam side  40  and a second surface or apply side  42 . The radially extending portion  43  extends between the radial outer end  38  and the radial inner end  39 . The piston arm  37  extends through the backing plate  21  out of the central cavity  22 . The radial ends  38 ,  39  are each sealed to the inner surface  20  of the housing  12  such that the actuator  18  divides the inner cavity  22 . The first surface  40  is located on a side of the actuator  18  opposite that of the second surface  42 . The second surface  42  includes a first area  44  and a second area  46 . The first area  44  is hydraulically isolated from the second area  46  by a seal  50  between the actuator  18  and the inner surface  20  of the housing  12 . The first surface  40 , the backing plate  21 , and the inner surface  20  of the housing  12  cooperate to define a dam space  52 . The first area  44  of the second surface  42  and the inner surface  20  of the housing  12  cooperate to define a first apply space  54 . The second area  46  of the second surface  42  and the inner surface  20  of the housing  12  cooperate to define a second apply space  56 . The dam space  52 , the first apply space  54 , and the second apply space  56  are all hydraulically isolated or sealed from one another by a plurality of the seals  50 . 
         [0034]    The actuator  18  is axially moveable within the cavity  22  between an unengaged position, illustrated in  FIG. 1 , and an engaged position. A biasing member  60  is located within the dam space  52  between the backing plate  21  and the actuator  18 . The biasing member  60  biases the actuator  18  into the unengaged position. The biasing member  60  may take various forms, such as, for example, a coil spring or leaf spring. When the actuator  18  is in the unengaged position, the reaction discs  26 ,  28  are not frictionally coupled and therefore torque is not transmitted between the housing  12  and the hub  14 . When the actuator  18  is in the engaged position, the piston arm  37  engages the clutch pack  16  and forces the reaction discs  26 ,  28  to move axially and frictionally engage one another. Accordingly, torque is transmitted between the housing  12  and the hub  14  through the clutch pack  16 . 
         [0035]    The quick fill mechanism  19  is connected to the actuator  18  to allow for selective fluid communication between the dam space  52  and the first apply space  54 . In the present embodiment, the quick fill mechanism  19  is connected to the radially extending portion  43  of the actuator  18 . The quick fill mechanism  19  includes a first port  64  in selective fluid communication with a second port  66 . The first port  64  is in fluid communication with the dam space  52  and the second port  66  is in fluid communication with the first apply space  54 . The quick fill mechanism  19  is preferably a valve, such as, for example, a ball valve having a valve ball for selectively allowing communication between the first port  64  and the second port  66  or a check valve or non-return valve that permits the fluid to pass through the quick fill mechanism in one direction only, such as from the first port  64  to the second port  66 . However, various other mechanisms that allow for selective fluid communication therethrough may be employed without departing from the scope of the present invention. Additionally, the size and capacity of the quick fill mechanism  19  of the present invention may vary, however, in a preferred embodiment the quick fill mechanism  19  is a 4 mm check or ball valve. The quick fill mechanism  19  is preferably in a normally closed state such that when the actuator  18  is in the unengaged position, hydraulic fluid cannot communicate through the quick fill mechanism  19 . However, as will be described in greater detail below, the quick fill mechanism  19  allows fluid to communicate from the dam space  52  to the first apply space  54  when the pressure of the fluid in the dam space  52  exceeds a threshold value. Moreover, while only one quick fill mechanism  19  is depicted in  FIG. 1 , it should be appreciated that a plurality of quick fill mechanisms  19  may be located in the actuator  18 . In a preferred embodiment, four quick fill mechanisms  19  are located in the actuator  18  and are spaced equidistant apart from one another. 
         [0036]    The multi-area clutch assembly  10  is controlled by a hydraulic control system  100 . The hydraulic control system  100  employed with the multi-area clutch assembly  10  may have various configurations and generally includes a plurality of fluid communication channels, solenoids, and valves that operate to actuate the multi-area clutch assembly  10 . For example, the hydraulic control system  100  includes a valve assembly  102  in communication with a supply line or channel  104  and a first fluid communication channel  106 . The supply line  104  is in fluid communication with a pump system (not shown) and delivers a pressurized fluid flow to the valve assembly  102 . The pressurized fluid flow may include any hydraulic fluid, such as, for example, an oil. The valve assembly  102  preferably includes a moveable valve and a plurality of fluid ports, though various other kinds of valve assemblies may be employed without departing from the scope of the present invention. The valve assembly  102  is operable to selectively allow the pressurized fluid flow delivered from the supply channel  104  to communicate through the valve assembly  102  into the first fluid channel  106 . The first fluid channel  106  is in fluid communication with the second apply space  56  of the multi-area clutch assembly  10 . 
         [0037]    The hydraulic control system  100  further includes a second fluid communication channel  108  having a first branch or portion  110  and a second branch or portion  112 . The first portion  110  is in fluid communication with the dam space  52  of the multi-area clutch assembly  10  and the second portion  112  is in fluid communication with the first apply area  54  of the multi-area clutch assembly  10 . In an alternate embodiment, the second portion  112  is selectively pressurized via a hydraulic actuator (not shown) in the event that more torque capacity is needed to keep the clutch pack  16  from slipping under high torque conditions. The hydraulic actuator is in a position that couples the second fluid communication channel  108  to the second portion  112  during engagement of the actuator  18 . A hydraulic fluid, such as an oil, is located within the dam space  52  and the first apply space  54 . 
         [0038]    During operation, the hydraulic control system  100  actuates the multi-area clutch assembly  10  by using the pressurized fluid flow to actuate the actuator  18 . For example, to engage the multi-area clutch assembly  10 , the valve  102  opens and permits the pressurized fluid flow to communicate through the valve  102 , through the first fluid communication channel  106 , and into the second apply space  56 . The pressurized fluid flow contacts the second area  46  of the actuator  18  and moves the actuator  18  against the spring  60  to the engaged position. As noted above, when the actuator  18  is in the engaged position, the piston arm  37  engages the clutch pack  16  and forces the reaction discs  26 ,  28  to move axially and frictionally engage one another. Accordingly, torque is transmitted between the housing  12  and the hub  14  through the clutch pack  16 . As the actuator  18  is urged into the engaged position, the dam space  52  decreases in volume while the first and second apply spaces  54 ,  56  increase in volume. Accordingly, as the volume of the dam space  52  decreases, the hydraulic fluid located within the dam space  52  is urged out into the first portion  110  of the second fluid communication channel  108 . A portion of the hydraulic fluid moves into the second portion  112  of the second fluid communication channel is delivered into the expanding first apply space  54 . Additional hydraulic fluid located in the dam space  52  passes through the quick fill mechanism  19  directly into the first apply space  54  when the pressure of the hydraulic fluid exceeds a threshold value sufficient to open the quick fill mechanism  19 . This prevents a vacuum from forming in the first apply space  54  as the pressurized hydraulic fluid flow urges the actuator  18  to the engaged position. 
         [0039]    The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.