Lubrication oil supply structure

Abstract

A main journal 25 a of a crank-shaped swinging shaft 25 which swings in a range of a predetermined angle is supported by bearing metals 51 and 52 each divided into two pieces. In supplying a lubrication oil through an oil bore 51 b in the bearing metal 51 to a sliding surface of the main journal 25 a and to inlet openings of lubrication oil passages P 1 and P 2 of the swinging shaft 25 open to the sliding surface, the inlet openings of the lubrication oil passages P 1 and P 2 of the swinging shaft 25 are designed so that they do not move past division portions 55 of the bearing metals 51 and 52 upon swing of the swinging shaft 25 in the range of the predetermined angle. Therefore, it is possible to prevent the lubrication oil to be supplied to the lubrication oil passages P 1 and P 2 from leaking from the division portions 55 of the bearing metals 51 and 52, thereby reliably lubricating a pin journal 25 b of the swinging shaft 25 by the lubrication oil supplied from the lubrication oil passages P 1 and P 2.

1 . A lubrication oil supply structure in which a lubrication oil passage formed within a rotary shaft is open to a journal which is supported by a bearing member divided into a plurality of pieces, wherein an opening of the lubrication oil passage of the rotary shaft is designed so that the opening does not stop at division portions of the bearing member.  
   
   
       2 . A lubrication oil supply structure in which a lubrication oil passage formed within a swinging shaft, which swings in a range of a predetermined angle, is open to a journal which is supported by a bearing member divided into a plurality of pieces, wherein an opening of the lubrication oil passage of the swinging shaft is designed so that the opening does not stop at division portions of the bearing member.  
   
   
       3 . A lubrication oil supply structure comprising: a crankshaft whose main journal is rotatably supported in an engine block; a control shaft whose main journal is supported in the engine block so as to swing in a range of a predetermined angle; a lower link swingably supported on a pin journal of the crankshaft; an upper link connecting the lower link to a piston; and a control link which connects the lower link or the upper link to a pin journal of the control shaft, the main journal of the control shaft being supported by a bearing metal divided into a plurality of pieces, a lubrication oil being supplied through the bearing metal to a sliding surface of the main journal of the control shaft and to an inlet opening of a lubrication oil passage which is formed within the control shaft and open to the sliding surface of the main journal of the control shaft, wherein the range of swing of the control shaft is determined so that the inlet opening of the lubrication oil passage of the control shaft does not move past division portions of the bearing metal divided into the plurality of pieces.  
   
   
       4 . A lubrication oil supply structure according to  claim 3 , wherein the lubrication oil passage of the control shaft is divided into a first lubrication oil passage open to the main journal of the control shaft, and a second lubrication oil passage open to the pin journal of the control shaft, the first and second lubrication oil passages being formed to intersect each other at a predetermined angle as viewed in an axial direction of the control shaft.