Abstract:
A lubrication device for an automatic transmission adapted to change the lubrication of both taper roller bearings rotatably supporting the output shaft of the automatic transmission between the automatic transmission case and torque converter housing. The disclosed device promotes a smooth lubrication in relation to both taper roller bearings even when the operation oil temperature is low and thus improves the durability of the taper roller bearings.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a lubrication device for an automatic transmission, and more particularly, to a lubrication device for transmission taper roller bearings.  
         BACKGROUND OF THE INVENTION  
         [0002]    In a conventional automatic transmission, the output shaft is supported by at least first and second taper roller bearings. In order to provide smooth operation and long life, lubrication is provided to the bearings. Generally, lubrication is provided through passages in the transmission/torque converter housing; flowing first to one bearing and subsequently, upon filling the oil passage, to the other bearing.  
           [0003]    As long as there is a sufficient supply of oil, both bearings are properly lubricated. However, when the viscosity of the oil is relatively high, before the engine and oil temperature rises sufficiently to thin the oil, adequate flow to the second bearing may not be supplied. Thus, a problem may arise with the lubrication of the second bearing, even when there is a sufficient volume of oil and the first bearing is properly lubricated. Such problems can result in the generation of eccentric friction and shortened life of the bearing.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention provides a lubrication device for an automatic transmission employing forced infusion and dispersion to ensure an adequate supply of oil through centrifugal force. The invention avoids decrease in lubrication performance resulting from a lack of mobility due to low lubrication oil temperature, thereby maximizing the durable life of taper roller bearings. Thus, in a preferred embodiment of the present invention, a first lubrication oil passage is formed inside a torque converter housing. A second lubrication oil passage communicates with the first lubrication oil passage within an output shaft rotatably supported via first and second taper roller bearings between the torque converter housing and the automatic transmission case.  
           [0005]    The first lubrication oil passage is provided at an inlet thereof with a first cap seal member equipped with an orifice. The second lubrication oil passage is provided at an inlet thereof with a second cap seal member equipped with a plurality of through holes. Thus, oil ejected under high pressure from the orifice of the first cap seal member passes or is dispersed through the plurality of through holes of the second cap seal member, thereby promoting the lubrication of the first and second taper roller bearings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    For fuller understanding of the nature and objects of the invention, reference should be made to the following detailed descriptions taken in conjunction with the accompanying drawings in which:  
         [0007]    [0007]FIG. 1 is a sectional view partially illustrating an output shaft area supporting the transfer driven gear of an automatic transmission and lubrication oil passages and lubrication device mounted thereto according to an embodiment of the present invention;  
         [0008]    [0008]FIG. 2 is a perspective view illustrating mounted areas of the taper roller bearings mounted at the torque converter housing illustrated in FIG. 1; and  
         [0009]    [0009]FIG. 3 is a plan illustrating through holes formed in the second cap seal member illustrated in FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0010]    Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings.  
         [0011]    As shown in FIG. 1, both ends of output shaft  12 , carrying a transfer driven gear  10 , are rotatably supported by a first taper roller bearing  18  and a second taper roller bearing  20 . The bearings are respectively secured to torque converter housing  14  and automatic transmission case  16 . Outer races  18   a  and  20   a , of the first and second roller bearings  18  and  20 , are respectively secured to the torque converter housing  14  and the automatic transmission case  16 . Inner races  18   b  and  20   b  thereof are respectively fixed at both ends of the output shaft  12 . Taper rollers  18   c  and  20   c  are mounted in a rolling fashion between the outer races  18   a  and  20   a  and the inner races  18   b  and  20   b . The outer race  18   a  of the first taper roller bearing  18  is centrally fixed at a boss  14   a  protrusively formed at the torque converter housing  14 .  
         [0012]    The torque converter housing  14  is preferably formed with a first lubrication oil passage  22 . Passage  22  bends approximately at a right angle to pass through the walls of the housing  14  and opens at a longitudinal end thereof toward the output shaft  12 . The output shaft  12  includes a centrally formed, second lubrication oil passage  24  running lengthwise through the shaft.  
         [0013]    The first and second lubrication oil passages  22  and  24  are arranged to communicate in an area adjacent the torque converter housing  14 . Oil flow is thus provided between gap  26 , formed between the output shaft  12  and the torque converter housing  14 , and gap  26 ′, between the output shaft  12  and the automatic transmission case  16 . At an inlet of the first lubrication oil passage  22  is formed at the torque converter housing  14 . A first cap seal member  40  is centrally equipped with an orifice. A second cap seal member  42 , equipped with a plurality of through holes  42   a  at the inlet of the second lubrication oil passage  24 , is disposed within oil passage  24  in shaft  12 .  
         [0014]    The first lubrication oil passage  22  is formed in boss  14   b , protruding from the wall of the torque converter housing  14 . The first lubrication oil passage  22  is configured to permit a smooth transition along first capsule member  40 , mounted at the inlet side of the first lubrication oil passage  22 . Boss  14   b  may be provided when the thickness of the member defining the torque converter housing  14  is insufficient for installation of the first cap seal member  40 .  
         [0015]    As shown in FIG. 3, the plurality of through holes  42   a  at the second cap seal member  42  are concentrically and radially formed, each being spaced apart from each other in the center of the member  42  in varying distances. A portion of high-pressure oil having passed the orifice  40   a  of the first cap seal member  40  is infused into the gap  26  formed between one end of the output shaft  12  and the torque converter housing  14 . The balance of the oil is introduced into the gap  26 ′ defined between the other end of the output shaft  12  and the automatic transmission case  16 , thereby promoting an equal distribution of the operational oil.  
         [0016]    As a result, the oil discharged by the oil pump (not shown) initially passes through first lubrication oil passage  22  formed in boss  14   b  on the torque converter housing  14 . Oil is then ejected towards one end of the second lubrication oil passage  24  disposed at the output shaft  12  through the orifice  40   a  centrally formed in the first cap seal member  40  mounted at the inlet side of the first lubrication oil passage  22 .  
         [0017]    Oil injected toward the second lubrication oil passage  24  at the output shaft  12  is ejected through the orifice  40   a , and is thereby discharged under high pressure such that part of the oil thus ejected hits the front side of the second cap seal member  42 . The oil is thereafter dispersed and infused into the gap  26 , promoting lubrication of the first taper roller bearing  18 . The balance of the oil passes through holes  42   a  in the second cap seal member  42  and again passes through the second lubrication oil passage  24  to be introduced into the gap  26 ′, thereby promoting lubrication of the second taper roller bearing  20 .  
         [0018]    In one lubrication method according to the invention, high pressure oil passes the orifice  40   a  at the first cap seal member  40  and is supplied respectively to the gaps  26  and  26 ′ formed at both ends of the output shaft  12  by way of forced infusion and dispersion via the second cap seal member  42 . The present invention thereby promotes smooth lubrication of the first and second taper roller bearings  18  and  20  rotatably supporting both ends of the output shaft  12 . Thus, the first and second taper roller bearings  18  and  20  rotatably supporting both ends of the output shaft  12  are smoothly lubricated even before the oil temperature is sufficient to recover mobility, thereby preventing eccentric friction of the bearings and maximizing the durable life of the bearings.