Abstract:
A piston engine includes a crankshaft bearing member and a bearing bushing which receive and rotatably support a crankshaft. The engine also includes a lubricant distribution sleeve which is mounted in the crankshaft bearing member for communicating with an engine lubrication system. The sleeve has an end which engages the bearing bushing and positions the bearing bushing within the crankshaft bearing member. The sleeve also includes a central bore and a radial port which communicate lubricant to the sleeve end and to the bearing bushing.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a crankshaft bearing and bushing assembly for a piston engine. 
     U.S Pat. No. 5,896,656 shows a lubricating arrangement for pistons or piston heads of a piston engine or an internal combustion engine. The lubricant is supplied through lubrication channels which supply the bearings or the bearing bushings of the crankshaft with lubricant. Lubricant supply channels which supply lubricant to the piston heads are formed in the cylinder block near the crankshaft bearings. It is known to mount spray nozzles into such lubricant supply channels in order to direct the lubricant to the piston heads for lubrication and cooling. Such nozzles are shown in Component Technical Manual, John Deere Usine de Saran, CTM3274 (Jul. 1, 1999). The aforementioned Component Technical Manual also shows such crankshaft bearings which provide positioning devices in the form of projections or depressions that can interact with corresponding depressions or projections on the cylinder block. Such designs require a costly configuration of the piston engine and the bearing bushings. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of this invention is to provide a low cost configuration for a piston engine and bearing bushings. 
     These and other objects are achieved by the present invention, wherein a piston engine includes a crankshaft bearing member and a bearing bushing which receive and rotatably support a crankshaft. The engine also includes a lubricant distribution sleeve which is mounted in the crankshaft bearing member for communicating with an engine lubrication system. The sleeve has an end which engages the bearing bushing and positions the bearing bushing within the crankshaft bearing member. The sleeve also includes a central bore and a radial port which communicate lubricant to the sleeve end and to the bearing bushing. 
     Preferably, the bearing bushing has a port formed therein which receives and engages the end portion of the sleeve. The bearing bushing also preferably includes an inner annular lubrication groove for distributing lubricant over the entire circumference of the bearing. Preferably, the lubrication groove is connected with the sleeve through the port, so that lubricant can flow from the sleeve to the lubrication groove or from the channel into the lubrication groove, depending upon how lubricant is provided. Lubricant is also supplied through the sleeve to the cylinder and piston or piston heads, to the crankshaft bearing, the bearing bushing. The end of the sleeve facing the cylinder forms a spray nozzle which can spray or distribute lubricant or coolant into regions of the cylinder block, so that these can be supplied uniformly with lubricant or coolant. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified sectional view of a piston engine showing a crankshaft supported in a crankshaft bearing. 
     FIG. 2 is a sectional view through a crankshaft bearing, a bearing bushing and a crankshaft in a direction perpendicular to the axis of the crankshaft and showing the lube distribution sleeve of the present invention. 
    
    
     DETAILED DESCRIPTION 
     A piston engine  10 , such as a compressor or an internal combustion engine, includes a cylinder block  12  in which one or more cylinders  14  are provided. Pistons  16  slide in the cylinders  14  and are connected to a crankshaft  20  by connecting rods  18  which are coupled to piston heads  19 . The crankshaft  20  is supported for rotation by crankshaft bearings  24 . Each bearing  24  includes a pair of bearing sections or parts  26 ,  28  which are bolted together by bolts (not shown). 
     Each crankshaft bearing  24  has a bore  36  extending therethrough which receives and supports a bearing bushing  29 . The bearing bushing  29  may have a one-piece configuration, but preferably has a two-piece design, and includes an upper bushing part  30  and a lower bushing part  32 . In the assembled condition the bushing parts  30 ,  32  are clamped together between the bolted bearing parts  26 ,  28  so that no movement of the bushing  29  is possible. The bearing bushing  29  and its parts  30 ,  32  must be positioned during the assembly in order to prevent any rotation or sliding during the installation, so that a correct fit is obtained and so that an unrestricted lubricant supply is assured. A relief port  54  extends radially through bushing part  30 . 
     The upper bearing part  26  is formed from a portion of the cylinder block  12 , and a lubrication channel  34  extends through part  26 . Channel  34  extends from the wall of bore  36  to a wall  38  of the bearing part  26  which faces the cylinder  14 . Channel  34  has larger and smaller diameter portions forming and separated by an annular shoulder  58 . Channel  34  is communicated through an opening  40  with the lubricating system (not shown) of the  10 , so that lubricant can reach the lubrication channel  34 . 
     A hollow sleeve  42  is mounted in channel  34 . Sleeve  42  has a central bore  43  and has a spray tip  44  on its outer end which faces the cylinder  14 . Bore  43  has a larger and smaller diameter portions which form an annular shoulder  60 . Sleeve  42  includes a radial relief port  48  which communicates with channel  34 , opening  40 , bore  36  and port  54  of the bushing  29 . The sleeve  42  has a smaller outer diameter end portion  50  which projects into bore  36  and which is received by port  33  of bushing part  30 . Spray tip  44  also has a smaller outer diameter than the main body of sleeve  42 , and tip  44  projects slightly beyond the wall  38  of the bearing part  26 . Spray tip  44  also has a wall thickness which is larger than the wall thickness of the main body of sleeve  42 . End portion  50  preferably forms hook-shaped elements for engaging the bushing part  30 . Alternatively, the sleeve  42  may be bonded or hot bonded to the bushing part  30 . Thus, lubricating or cooling fluid can be supplied to cylinder  14  of engine  10  through the bore  43  of sleeve  42  and the spray tip  44 . Alternatively, sleeve  42  may include circumferental grooves (not shown) for supplying lubricant therethrough. 
     The insertion of sleeve end portion  50  into port  54  of bushing part  30  and the engagement of sleeve end portion  50  with bushing part  30  holds the upper bushing part  30 , and thereby the entire bearing bushing  29 , in position within bore  36  of the bearing part  26 . Alternatively, a positioning spike or similar device (not shown) could be provided on or in the sleeve  42 . But, preferably the sleeve  42  is configured as a one-piece component. The relief port  54  in the bearing bushing  29  may be a depression that is formed or machined into its surface. Preferably, the port  54  is a bore which extends through the bushing  29 . 
     Preferably, the sleeve  42  is made of a plastic material, since the sleeve  42  is subject to only low loads when it is installed in channel  34 . Alternatively, sleeve  42  could be made out of a metallic material and turned on a lathe. 
     In addition, an inner annular groove  56  is formed in both bushing parts  30 ,  32 , so that the groove  56  extends around the entire inner surface of the bushing  29 , in order to distribute the lubricant uniformly. Thus, groove  56  is communicated with opening  40  via port  48 , so that flow of lubricant is possible through the opening  40  in the cylinder block  12  to the lubricating system, through the spray tip  44  to the cylinder  14  and to the piston head  19 , as well as into the bearing bushing  29 . Thus, sleeve  42  distributes lubricant and also positions the bearing bushing  29  during assembly. 
     The assembly of the bearing bushing  29  with the bearing parts  30 ,  32  and the crankshaft  20  is performed by first inserting the sleeve  42  from the wall of bore  36 , preferably with a drive fit, until sleeve shoulder  60  engages shoulder  58 . The sleeve  42  is retained in the bearing part  26  in a friction locking fit. Alternatively, sleeve  42  may be retained by a positive locking fit, such as by a threaded engagement between an external thread (not shown) on the sleeve  42  and an internal thread (not shown) provided in the channel  34 . Following this, the first bushing part  30  is inserted into the bearing part  26 , preferably, while the cylinder block  12  is oriented so that the bushing part  30  and other components, such as the crankshaft  20 , can be placed on the bearing part without being retained by hand. In order to position the bushing part  30 , the end  50  of the sleeve  42  is inserted into the port  54  in the bushing part  30 , to prevent bushing part  30  from rotating or sliding with respect to the bearing part  26 , and the cylinder block  12 . 
     After placing the first bushing part  30 , the crankshaft  20  is placed into it and bushing part  30 , and then the second bushing part  32  is installed so that the position of the entire bearing bushing  29  is determined by the engagement of sleeve  42  through the first bushing part  30  and by the engagement of the crankshaft  20  with the bushing  29 . 
     Finally, the second bearing part  28  is bolted to bearing part  26 , so that the bearing bushing  29  or its parts  30 ,  32  are clamped therebetween with a friction locking fit. Since the bearing bushings  29  are clamped during operation between the bolted bearing parts  26 ,  28 , no or little load is applied to the sleeve  42  during operation of the engine  10 . 
     While the present invention has been described in conjunction with a specific embodiment, it is understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the spirit and scope of the appended claims.