JP2007205214A - Crankshaft bearing structure for multiple cylinder engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing structure facilitating attachment of a bearing pivotally supporting a crank shaft of a multiple cylinder engine. <P>SOLUTION: This crankshaft intermediate bearing structure for the multiple cylinder engine is provided with bearing holes 6F, 6B through a front and a rear end wall 4, 5 of a cylinder block 3, and pivotally supports both end parts of the crank shaft 7 at the bearing hole 6. An end surface center part of a crank chamber partition wall 15 positioned in the crank chamber 14 in the cylinder block 3 is depressed to a cylinder side to form a semicircular crankshaft insertion through part 16. A semicircular bearing holder 17 is fitted in the crankshaft insertion through part 16 and a bearing cap 18 is fixed on the crank chamber partition wall 15 by a plurality of bolts 21, 21. The bearing holder 17 is fixed on the bearing cap 18 by a plurality of bolts 22, 22. The intermediate bearing part of the crankshaft is composed of the bearing holder 17 and the bearing cap 18. A journal part of the crankshaft 7 is born by the bearing fitted in the intermediate bearing part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a crank bearing structure in a multi-cylinder engine, and more particularly to a bearing structure that supports an intermediate portion of a crank shaft in a multi-cylinder engine of a type in which both ends of the crank shaft are supported by a so-called tunnel structure.

  In an engine having a piston / crank mechanism, the piston receiving the explosion pressure inside the cylinder is pushed down, and the crankshaft connected to the piston via a connecting rod is rotated to obtain power. In the bearing portion of the crankshaft, the crankshaft is supported so as to rotate at high speed while receiving a complicated force resulting from pressure fluctuations inside the cylinder.

Conventionally, in a multi-cylinder engine, in order to hold the crankshaft firmly, bearing holes are provided in the front and rear end walls of the cylinder block and the partition walls partitioning the crank chamber corresponding to the cylinder walls. There is known a tunnel-type bearing system in which a crankshaft is pivotally supported in a bearing hole via a bearing box (bearing case). (Patent Document 1)
JP-A-8-31457

  When the intermediate bearing portion of the crankshaft is supported by a bearing hole that is formed through the partition wall of the crank chamber via the bearing box, the positioning of the set screw for mounting and fixing the bearing box in the bearing hole is troublesome. There was a problem that it took time to set the bearing box in the section.

  Also, since a set screw is used when mounting and fixing the bearing housing in the bearing hole, the bearing housing is pulled or pressed by the tightening force, and the shaft core of the bearing housing and the crankshaft There is also a problem that a deviation tends to occur due to the relationship between the core and the shaft core of the bearing hole.

  The present invention has been made paying attention to such a point, and an object thereof is to provide a bearing structure in which a bearing for pivotally supporting a crankshaft of a multi-cylinder engine can be easily attached.

  In order to achieve the above-described object, the present invention provides a cylinder block in a multi-cylinder engine in which bearing holes are formed through the front and rear end walls of the cylinder block and both ends of the crankshaft are pivotally supported by the bearing holes. The center of the end face of the crank chamber partition wall located in the inner crank chamber is recessed toward the cylinder side to form a semicircular crankshaft insertion portion, and a semicircular bearing holder is fitted into this crankshaft insertion portion, The bearing cap is fixed to the wall with a plurality of bolts, and the bearing holder is fixed to the bearing cap with a plurality of bolts. The bearing holder and the bearing cap constitute an intermediate bearing portion of the crankshaft, and are fitted into the intermediate bearing portion. It is characterized in that the journal part of the crankshaft is supported by a worn bearing.

  In the present invention, the intermediate bearing portion of the crankshaft has a so-called hanger type bearing structure constituted by a bearing holding portion and a bearing cap formed at the center of the end face of the crank chamber partition wall located in the crank chamber. Easy to set. Further, the crank shaft core and the bearing hole shaft core are unlikely to shift.

  Furthermore, since both ends of the crankshaft are bearings having a tunnel structure, the cylinder block wall has a higher strength and is less likely to vibrate compared to a split structure such as a hanger type.

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a sectional view of a main part, FIG. 2 is an overall longitudinal front view, and FIG. 3 is a longitudinal side view.
In this engine, a bearing hole (6) is formed through the front and rear end walls (4) and (5) of a cylinder block (3) in which a cylinder case (1) and a crankcase (2) are integrally formed. The front and rear ends of the crankshaft (7) are rotatably supported in the bearing hole (6).

A bearing hole (6F) formed in the front wall (4) of the cylinder block (3) is formed to have a diameter that allows the sliding bearing (8) mounted on the front journal portion of the crankshaft (7) to be fitted. is there.
On the other hand, the bearing hole (6B) pierced in the rear wall (5) of the cylinder block (3) has a virtual diameter formed by the outer end surface of the counterweight (9) formed in the crankshaft (7). The rolling bearing (10) mounted on the rear journal portion of the crankshaft (7) is inserted into the bearing hole (6B) through a bearing box (bare link case) (11). By mounting, the crankshaft (7) is pivotally supported by the cylinder block (3). Reference numeral (12) in the figure denotes a pressing lid for fixing the bearing housing.

  The crankshaft (7) has an intermediate journal portion supported by an intermediate bearing portion (13). The intermediate bearing portion (13) includes a crankshaft insertion portion (16) formed by cutting a partition wall (15) disposed in a state corresponding to the cylinder wall in the crank chamber (14) into a semicircular shape, A bearing holder (17) fitted in the crankshaft insertion portion (16) and a bearing cap (18) attached and fixed to the lower end surface of the partition wall (15) are configured.

  The crankshaft insertion portion (16) formed in the partition wall (15) disposed in the crank chamber (14) is formed in a lower surface open shape. The bearing holder (17) is formed in a half donut shape, and its outer diameter is formed substantially equal to the inner diameter of the crankshaft insertion portion (16), and the inner diameter is formed in the journal portion of the crankshaft (7). It is formed substantially equal to the outer diameter of the mounted slide bearing (19). The inner diameter of the crankshaft insertion portion (16) is slightly larger than the virtual diameter formed by the outer end surface of the counterweight (9) formed on the crankshaft (7). (7) is made so as not to hinder the insertion.

  The bearing cap (18) has a semicircular recess (20) formed on its upper surface so as to receive the lower half of the slide bearing (19) attached to the journal portion of the crankshaft (7). The bearing cap (18) is provided with two pairs of fixing bolts (21) and (22), and the pair of fixing bolts (21) located outside the bearing cap (18) defines the partition wall ( A pair of fixing bolts (22) fixed to 14) and located inside are used to integrate the bearing holder (17) and the bearing cap (18).

  In the crank bearing structure of the engine thus configured, the crankshaft (7) is set with the oil pan (23) arranged so as to cover the lower surface of the crank chamber (14) removed. Therefore, the fixing bolt (22) mounted between the bearing holder (17) mounted on the journal portion of the crankshaft (7) located in the crank chamber (14) and the bearing cap (18), The operation of the fixing bolt (21) mounted between the partition wall (15) and the bearing cap (18) can be performed in a so-called open space, and the intermediate bearing operation of the crankshaft (7) is easy. This can be done reliably and reliably.

  The present invention can be applied not only to a vertical multi-cylinder engine but also to an intermediate bearing in a crank chamber of various types of multi-cylinder engines.

It is an extraction sectional view of the important section showing one embodiment of the present invention. It is the whole longitudinal front view showing one embodiment of the present invention. It is a vertical side view which shows one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Cylinder block, 4 * 5 ... Front-and-rear end wall, 6 ... Bearing hole, 7 ... Crankshaft, 11 ... Bearing box, 13 ... Bearing holding part, 14 ... Crank chamber, 15 ... Crank chamber partition wall, 16 ... Crank chamber insertion part, 17 ... bearing holder, 18 ... bearing cap, 19 ... bearing, 21/22 ... bolt.

Claims (1)

Bearing holes (6F) and (6B) are formed through the front and rear end walls (4) and (5) of the cylinder block (3), and both ends of the crankshaft (7) are pivotally supported by the bearing holes (6). In a multi-cylinder engine,
The center of the end face of the crank chamber partition wall (15) located in the crank chamber (14) in the cylinder block (3) is recessed toward the cylinder to form a semicircular crank shaft insertion portion (16). A semicircular bearing holder (17) is inserted into the part (16), and the bearing cap (18) is fixed to the crankcase partition wall (15) with a plurality of bolts (21) (21). The bearing holder (17) is fixed with a plurality of bolts (22) and (22), and the bearing holder (17) and the bearing cap (18) constitute an intermediate bearing portion of the crankshaft, which is fitted into the intermediate bearing portion. A crank bearing structure for a multi-cylinder engine, characterized in that the journal portion of the crankshaft (7) is supported by the attached bearing (19).

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