Abstract:
A centrifugal debris trap is provided for collecting debris within various parts of the transmission. The debris trap includes a porous material that disposed in various parts of the transmission. For example, the debris trap may be located within or on any transmission component that rotates or is stationary and that contacts automatic transmission fluid. Particular locations of the debris trap include but are not limited to the torque converter, damper, one or more clutch hubs, one or more clutch pistons, one or more clutch piston dams, including rotating hubs, rotating housings and rotating pistons, gears, gear carriers, electric motors, sprockets, bearings, and flanges.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/721,163, filed on Nov. 1, 2012, which is herein incorporated by reference in its entirety. 
     
    
     FIELD 
       [0002]    The present invention relates to an apparatus for filtering fluid, and more specifically to a debris trap for use in an automotive transmission. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present invention and may or may not constitute prior art. 
         [0004]    A typical automatic transmission includes an electronically controlled hydraulic control circuit or system that uses a hydraulic fluid to actuate torque transmitting mechanisms, as well as to lubricate and cool the transmission. The hydraulic fluid is typically stored in a fluid reservoir, or sump, disposed at a bottom of the transmission. A pump connected to the sump is used to draw the hydraulic fluid from the sump and communicate the hydraulic fluid throughout the hydraulic control system. Engines also use fluids for lubrication and cooling, which may be filtered through a canister filter or other means. 
         [0005]    In order to prevent damage to the control system or other components due to unwanted contaminants that may be present in the powertrain fluid, a filter is generally connected to the pump. The filter includes a filter element surrounded by a filter body having an inlet for incoming fluid and an outlet for outgoing fluid. The filter removes some of the contaminants from the fluid prior to entering the pump. In other words, the pump draws in fluid through the filter. 
         [0006]    However, the filter only traps debris after it has returned to the sump, and some debris may pass through the filter even after the debris has collected in the sump. Accordingly, the filter is ineffective to trap debris immediately after the debris is generated and before the debris collects in the sump, or when the debris escapes from the sump. Debris can cause issues within the transmission hydraulic system. Therefore, additional debris collection apparatus or systems are desired. 
       SUMMARY 
       [0007]    In an example of the present invention, a centrifugal debris trap is provided for collecting debris within various parts of the transmission. The debris trap includes a porous material that disposed in various parts of the transmission. For example, the debris trap may be located within or on any transmission component that rotates or is stationary and that contacts automatic transmission fluid. Particular locations of the debris trap include but are not limited to the torque converter, damper, one or more clutch hubs, one or more clutch pistons, one or more clutch piston dams, including rotating hubs, rotating housings and rotating pistons, gears, gear carriers, electric motors, sprockets, bearings, and flanges. 
         [0008]    In one form, which may be combined with or separate from other forms described herein, a filtering assembly for collecting sediment particles from fluid of a powertrain device is provided. The filtering assembly includes a transmission part selected from the group consisting of: torque converter, damper, clutch hub, clutch piston, clutch housing, clutch piston dam, gear, gear carrier, electric motor, sprocket, bearing, flange, wall of pump housing, and pressure plate assembly. The filtering assembly also includes a sediment trap having a porous surface. The sediment trap is attached to the transmission part. 
         [0009]    In another form, which may be combined with or separate from the other forms described herein, a filtering assembly for collecting sediment particles from fluid of a powertrain device is provided, and the filtering assembly includes a transmission part disposed in one of a main transmission case and a bell housing. A sediment trap having a porous surface is also provided. The sediment trap defines a plurality of pores and surrounding structures. The plurality of pores is configured to allow sediment particles to enter the sediment trap through the pores. The surrounding structures are configured to trap the sediment particles. The plurality of pores have an open cell configuration wherein the pores are interconnected with each other. The sediment trap is attached to the transmission part. 
         [0010]    In yet another form, which may be combined with or separate from the other forms described herein, a method for collecting sediment from fluid of an automotive transmission is provided. The method includes receiving sediment particles through a porous surface of a sediment trap disposed in a cavity formed by one of a transmission case and a bell housing, wherein the porous surface of the sediment trap is configured to receive the sediment particles from transmission fluid. The method further includes trapping the sediment particles within the sediment trap. 
         [0011]    Further examples and aspects 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. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0013]      FIG. 1  is cross-sectional view of a transmission torque converter assembly having a debris trap, in accordance with the principles of the present disclosure; 
           [0014]      FIG. 2  is a plan view of the debris trap of  FIG. 1 , according to the principles of the present disclosure; 
           [0015]      FIG. 3  is a schematic cross-sectional side view of a transmission assembly including the transmission torque converter assembly of  FIG. 1 , in accordance with the principles of the present disclosure; 
           [0016]      FIG. 4  is a schematic cross-sectional side view of the transmission assembly of  FIG. 3 , having additional debris traps, according to the principles of the present disclosure; and 
           [0017]      FIG. 5  is a schematic cross-sectional side view of the transmission assembly of  FIGS. 3 and 4 , having still additional debris traps, in accordance with the principles of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The present disclosure provides a debris trap within rotating and non-rotating transmission components. The debris trap is comprised of one or more porous materials and is intended to catch and retain debris present in automatic transmission hydraulic systems. The debris trap may also be used in an engine or other powertrain component that uses hydraulic fluid. 
         [0019]    Referring now, to  FIG. 1 , a cross-section of a portion of automatic transmission assembly  10  is illustrated. The automatic transmission assembly  10  includes a bell housing  12  attached to an end, which includes a torque converter assembly  13  including a pump housing  17  and a torque converter  14  disposed therein. A debris trap  16  is disposed in the bell housing  12  to collect any debris present in automatic transmission fluid flowing past the debris trap  16 . 
         [0020]    The debris trap  16  may be formed of a porous material, to collect debris. Referring to  FIG. 2 , the porous material may be open cell, wherein the debris trap  16  contains portions forming a plurality of pores  18  that are interconnected with each other. In the alternative, the porous material used for the debris trap  16  may have closed cell pores that are not interconnected with each other. Though the debris trap  16  is shown as solid in  FIG. 1  for simplicity of illustration, it should be understood that the debris trap  16  of  FIG. 1  is actually porous as illustrated more particularly in  FIG. 2 . 
         [0021]    Various different materials could be used for the debris trap  16 . For example, the debris trap  16  could comprise a powdered metal sintered material, which may include a ferrous material, aluminum, steel, such as stainless steel, bronze, nickel-based alloys, nickel, titanium, copper, platinum, silver, tungsten, molybdenum, and/or magnesium. The various metals may be combined with each other or other materials. The debris trap  16  could comprise a powdered metal foam material, such as a powdered aluminum foam. In one variation, the debris trap  16  could comprise a metal matrix composite (MMC) material. One example of an acceptable material for the debris trap  16  is marketed under the trademark Duocell®, which is a porous structure or open-celled foam including a network of solid struts and which may include about 5-40 pores per inch (for metals) and 5-100 pores per inch (for other materials). The debris trap  16  could also or alternatively include a plastic or composite material, a fibrous material, or another cellular structure material. In some variations, the debris trap  16  may be formed by casting or any other suitable process. 
         [0022]    The pores  18  of the debris trap  16  may be of a uniform size throughout the debris trap  16 , or the size of the pores  18  may vary with depth. For example, the debris trap  16  may have an outer layer of 100 micron diameter pores  18 , a second layer immediately beneath and adjacent to the top layer of 50 micron diameter pores  18 , a third layer immediately beneath and adjacent to the second layer of 25 micron diameter pores  18 , a fourth layer immediately beneath and adjacent to the third layer of 10 micron diameter pores  18 , and an inner layer immediately beneath and adjacent to the fourth layer having 1 or ½ micron diameter pores  18 . The debris trap  16  could have any combination of the layers described, in another variation. For example, the debris trap  16  could simply have an outer layer with 25 micron diameter pores  18  and an inner layer of 1 or ½ micron diameter pores  18 . In some variations, the debris trap  16  may be about 90% or more porous. 
         [0023]    Referring now to  FIG. 3 , the debris trap  16  is illustrated within the transmission assembly  10 . As described above with respect to  FIG. 1 , the debris trap  16  is located in the torque converter  14  near the pump housing  17 . The debris trap  16  is attached to a wall  20  of the pump housing  17  so that the debris trap  16  collects debris in the automatic transmission fluid that flows through the torque converter  14 . Additional debris traps  16 A,  16 B,  16 C are located in the torque converter  14 , which are also configured to collect debris from the automatic transmission fluid that flows through the torque converter  14 . For example, the debris trap  16 C is attached to the stator  22  of the torque converter  14 ; debris trap  16 B is attached to the converter housing cover  23 ; and debris trap  16 A is attached to the pressure plate assembly  25 . The additional debris traps  16 A,  16 B,  16 C may be identical to the debris trap  16 , or the debris traps  16 A,  16 B,  16 C may embody any variation of the debris trap  16  described herein. 
         [0024]    Further, additional debris traps  16 D,  16 E,  16 F,  16 G may be located inside the main transmission case  28  of the transmission assembly  10 . Each of the debris traps  16 D,  16 E,  16 F,  16 G is located in or on a rotating clutch hub  30  or another rotating hub  32 . The debris traps  16 D,  16 E,  16 F,  16 G are configured to collect debris from the automatic transmission fluid that flows through or around the rotating clutches  34 . The additional debris traps  16 D,  16 E,  16 F,  16 G may be identical to the debris trap  16 , or the debris traps  16 D,  16 E,  16 F,  16 G may embody any variation of the debris trap  16  described herein. 
         [0025]    Referring now to  FIG. 4 , the transmission assembly  10  is illustrated having debris traps  16 H,  16 I,  16 J,  16 K,  16 L,  16 M disposed in still other locations within the transmission assembly  10 . Though the previously described debris traps  16 ,  16 A,  16 B,  16 C,  16 D,  16 E,  16 F,  16 G are not illustrated in  FIG. 4 , one having ordinary skill should understand that the earlier described debris traps  16 ,  16 A,  16 B,  16 C,  16 D,  16 E,  16 F,  16 G could be disposed in the transmission assembly  10  along with the debris traps  16 H,  16 I,  16 J,  16 K,  16 L,  16 M. Debris traps  16 H,  16 J, and  16 L are attached to rotating clutch pistons  36 ,  38 ,  40  or to components adjacent to the rotating clutch pistons  36 ,  38 ,  40 , respectively. Debris traps  16 I,  16 K, and  16 M are attached to rotating clutch dams  42 ,  44 ,  46 , respectively. The debris traps  16 H,  16 I,  16 J,  16 K,  16 L,  16 M are configured to collect debris from the automatic transmission fluid that flows through the rotating clutches  34  and around and into the pistons  36 ,  38 ,  40  and dams  42 ,  44 ,  46 . The additional debris traps  16 H,  16 I,  16 J,  16 K,  16 L,  16 M may be identical to the debris trap  16 , or the debris traps  16 H,  16 I,  16 J,  16 K,  16 L,  16 M may embody any variation of the debris trap  16  described herein. 
         [0026]    Referring now to  FIG. 5 , the transmission assembly  10  is illustrated having debris traps  16 N,  16 O,  16 P,  16 Q,  16 R disposed in still other locations within the transmission assembly  10 . Though the previously described debris traps  16 ,  16 A,  16 B,  16 C,  16 D,  16 E,  16 F,  16 G,  16 H,  16 I,  16 J,  16 K,  16 L,  16 M are not illustrated in  FIG. 5 , one having ordinary skill should understand that the earlier described debris traps  16 ,  16 A,  16 B,  16 C,  16 D,  16 E,  16 F,  16 G,  16 H,  16 I,  16 J,  16 K,  16 L,  16 M could be disposed in the transmission assembly  10  along with the debris traps  16 N,  16 O,  16 P,  16 Q,  16 R. 
         [0027]    Debris traps  16 N,  16 O are attached to rotating clutch housings  48 ,  50 , respectively. Debris trap  16 P is attached to a rotating gear  52 , which is a ring gear in this variation. Debris traps  16 Q,  16 R are attached to a carrier  54 . The debris traps  16 N,  16 O are configured to collect debris from the automatic transmission fluid that flows through or around the rotating clutches  34  and through around the clutch housings  48 ,  50 . The debris trap  16 P is configured to collect debris from the automatic transmission fluid that flows past or through the ring gear  52 , and the debris traps  16 Q,  16 R are configured to collect debris from the automatic transmission fluid that flows past or through the carrier  54 . The debris traps  16 N,  16 O,  16 P,  16 Q,  16 R may be identical to the debris trap  16 , or the debris traps  16 N,  16 O,  16 P,  16 Q,  16 R may embody any variation of the debris trap  16  described herein. 
         [0028]    The debris traps  16 ,  16 A,  16 B,  16 C,  16 D,  16 E,  16 F,  16 G,  16 H,  16 I,  16 J,  16 K,  16 L,  16 M,  16 N,  16 O,  16 P,  16 Q,  16 R may be centrifugal debris traps through which hydraulic fluid does not flow, but rather, debris is trapped via centrifugal force caused by rotation. In addition, or in the alternative, the debris traps  16 ,  16 A,  16 B,  16 C,  16 D,  16 E,  16 F,  16 G,  16 H,  16 I,  16 J,  16 K,  16 L,  16 M,  16 N,  16 O,  16 P,  16 Q,  16 R may be centrifugal debris filters through which fluid does flow and which strain debris via AP caused by rotation. Accordingly, the debris traps  16 ,  16 A,  16 B,  16 C,  16 D,  16 E,  16 F,  16 G,  16 H,  16 I,  16 J,  16 K,  16 L,  16 M,  16 N,  16 O,  16 P,  16 Q,  16 R may trap or filter debris that is built in or self-generated within a transmission assembly  10 . Centrifugal forces driving the automatic transmission fluid outward may cause the fluid to flow over one or more of the debris traps, and debris to become seated or trapped therein. 
         [0029]    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.