JP2013002557A - Connecting rod assembling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connecting rod assembling method that regulates displacement of a body and a bearing cap in a shaft-hole radial direction parallel to the division surface between the body and the bearing cap by utilizing split bearings without using a positioning member such as a knock pin.SOLUTION: The connecting rod assembling method is configured as follows. Split bearings 7a, 7b are respectively set into a cap side shaft hole 9b of a bearing cap 12 and a body side shaft hole 9a of a body 11 in a state that the straight line connecting both ends of the split bearing is rotated by a prescribed amount in a circumferential direction of the shaft hole from the division surface (a) of the shaft holes. A crank pin 4a is fitted into either one of the cap side shaft hole and the body side shaft hole respectively into which the split bearing is set. Then, the ends protruding from the division surface are respectively inserted to the inner surface of the shaft hole in which the end of the split bearing on the mating side retreats, thereby assembling a connecting rod 5. The method regulates displacement of the body and the bearing cap of the connecting rod in a shaft-hole radial direction parallel to the division surface (a) of the body and the bearing cap by the ends of the split bearings inserted into the inner surfaces of the shaft holes.

Description

  The present invention relates to a method for assembling a connecting rod that is connected to a crank pin via a bearing metal.

A reciprocating engine mounted on an automobile connects the large end of a connecting rod extending from a piston to a crank pin of a crankshaft so as to be rotatable, and converts the reciprocating motion of the piston into rotational motion and transmits it to the crankshaft. Yes.
In general, the large end portion of the connecting rod is connected to a crank pin through an annular bearing metal. These connecting rods are equally divided (divided in two) into the main body and bearing cap, with the center of the shaft hole through which the crank pin is inserted, and the bearing metal is divided into two semicircular shapes. The bearings are set in the main body side shaft hole and the cap side shaft hole, respectively, and the main body side shaft hole and the cap side shaft hole in which the divided bearings are set are fitted to the crank pins one by one.

By the way, the main body of the connecting rod and the bearing cap may be displaced in the axial hole radial direction parallel to the split surface of the main body and the bearing cap when assembled.
Therefore, in the connecting rod, a positioning member such as a knock pin disclosed in Patent Document 1 is used to restrict the connecting rod main body and the bearing cap from being displaced in the radial direction parallel to the dividing surface. Yes.

Japanese Utility Model Publication No. 1-96519

However, the regulation of the split bearing using a positioning member such as a knock pin has a problem that the cost is high and the workability is also poor.
Therefore, an object of the present invention is to provide a connecting rod assembling method that uses a split bearing without using a positioning member such as a knock pin and regulates a shift in a shaft hole radial direction parallel to the split surface of the main body and the bearing cap. It is to provide.

  In order to achieve the above object, the method of assembling the connecting rod according to claim 1, the divided bearing caps, the cap-side shaft holes and the body-side shaft holes of the main body are divided into semicircular shapes, respectively. Set with the straight line connecting both ends of the split bearing rotated by a predetermined amount in the circumferential direction of the shaft hole from the split surface of the shaft hole, either the cap side shaft hole or the body side shaft hole where the split bearing is set After fitting the crankpins, the connecting rods were assembled by inserting the end portions protruding from the split surfaces into the inner surfaces of the shaft holes from which the respective split bearing ends were recessed.

By this method, the displacement of the connecting rod main body and the bearing cap in the axial hole radial direction parallel to the divided surface of the main body and the bearing cap is regulated by the end of the split bearing inserted into the inner surface of the shaft hole.
According to the second aspect of the present invention, the predetermined amount is positioned in the vicinity of the protruding end of the split bearing and the other end of the split bearing so that the position adjustment of the split bearing is not required when further fitting to the crankpin. The opening width formed by the end of the dividing surface is set to be larger than the diameter of the crankpin.

  According to a third aspect of the present invention, in order to further reduce the resistance between the assembled bearing metal and the crank pin, one end of the split bearing is formed with a thin wall in which the thickness in the radial direction is thinner from the inner peripheral side than the other end. The split bearings are set on the bearing cap and the main body so that the thin end portion is located on the end portion and on the delay side of the crank pin in the rotation direction.

According to the first aspect of the present invention, the main body of the connecting rod and the bearing cap to be assembled are divided by the ends of the divided bearings inserted from the main body side shaft hole to the cap side shaft hole and from the cap side shaft hole to the main body side shaft hole. Deviation to the axial hole radial direction parallel to the surface is restricted.
Therefore, by using a split bearing without using a positioning member such as a knock pin, it is possible to restrict the main body and the bearing cap from shifting in the axial hole diameter direction parallel to the split surface, thereby reducing costs and improving workability. I can plan.

According to the second aspect of the present invention, it is not necessary to adjust the position of the split bearing when fitting to the crankpin, so that the workability at the time of assembly can be further improved.
According to the invention of claim 3, since the end located on the rotation direction delay side of the crankpin is thinner than the adjacent end on the dividing surface, even if there is an assembly error or a manufacturing error, It can suppress that the same edge part protrudes in an axial hole radial inside rather than the edge part adjacent on a division surface, and can suppress the increase in resistance of the bearing metal and crank pin at the time of rotation of a crank pin.

The perspective view which shows the connecting rod which concerns on one Embodiment of this invention with the piston of an internal combustion engine, and a crankshaft. FIG. The disassembled front view of the connecting rod explaining the method of assembling the connecting rod. The front view of the connecting rod which shows the becon rod assembled to the cylinder shape.

Hereinafter, the present invention will be described based on an embodiment shown in FIGS.
1 shows the crankshaft around the reciprocating engine (internal combustion engine), FIG. 2 shows the connecting rod attached to the crankshaft, FIG. 3 shows the details of the connecting rod and the assembly method of the bear rig metal, and FIG. The entire connecting rod is shown.
First, FIG. 1 and FIG. 2 will be explained. In the figure, 1 is a cylinder block, 2 is a cylinder formed in the cylinder block 1, and 3 is housed in the cylinder 2 so as to be able to reciprocate. 4 is a crankshaft assembled to the cylinder block 1 corresponding to the cylinder 2, and 5 is a connecting rod (connecting rod) connecting the piston pin 3a of the piston 3 and the crankpin 4a of the crankshaft 4. ).

2 and 4, the connecting rod 5 is a rod member having a small end 5a at the upper end (one end) and a large end 5a at the lower end (the other end). It is formed. The small end portion 5a is fitted to the piston pin 3a of the piston 4, and the large end portion 5b is fitted to the crank pin 4a so as to convert the reciprocating motion of the piston 4 into a rotational motion.
The large end 5b is rotatably connected to the crank pin 4a by a structure using an annular bearing metal 7 as shown in FIG. The large end 5b uses a rod main body 11 (corresponding to the main body of the present application) and a bearing cap 12 which are divided into two equal parts, with the coaxial hole 9 being equally divided at the center of the shaft hole 9 through which the crank pin 4a is inserted. Two semi-circular shaft holes 9a (corresponding to the main body side shaft holes) of the rod body 11 and two semicircular shaft holes 9b (corresponding to the cap side shaft holes) of the bearing cap 12 A structure in which divided bearings 7a and 7b divided into circular shapes are set is used. That is, the connecting rod 5 is assembled when the shaft holes 9a and 9b in which the split bearings 7a and 7b are set are fitted to the crank pins 4a existing between the vertical walls 4b such as a counterweight. a indicates a split surface between the rod body 11 and the bearing cap 12, and b indicates a split surface (contact surface) of the split bearings 7a and 7b.

In the connecting rod assembling method for assembling the connecting rod 5, the rod body 11 and the bearing cap 12 are mounted in the axial hole radial direction parallel to the dividing surface a by using the divided bearings 7a and 7b without using a positioning member such as a knock pin. A method of assembling so as not to shift is used. The same method is shown in FIG.
This assembly method will be described. The split bearings 7a and 7b are respectively inserted into the shaft hole 9a (main body side shaft hole) of the rod body 11 and the shaft hole 9b (cap side shaft hole) of the bearing cap 12, respectively. 7b is set in a state where a straight line L (shown by a one-dot chain line on one side in FIG. 3) is rotated by a predetermined amount in the circumferential direction from the dividing surface a of the shaft holes 9a, 9b. Here, the split bearings 7a and 7b are set in the shaft holes 9a and 9b, respectively, in such a posture that the end 7c opposite to the rotation direction of the crank pin 4a protrudes from the split surface a of the shaft hole 9a by a predetermined amount. . That is, in the split bearing 7a set in the shaft hole 9a, one end portion 7c (left side in the figure) protrudes outward from the split surface a of the shaft hole 9a, and the other end portion 7d (right side in the figure) has the shaft hole. Retreat inward from the dividing surface 9a. The split bearing 7b set in the shaft hole 9b is opposite to the rod body 11 side, and the other (right side in the figure) end 7f protrudes outward from the split surface a of the shaft hole 9b, and the other (left side in the figure). The end portion 7e retracts inward from the split surface a of the shaft hole 9b.

Thereafter, one of the shaft hole 9a and the shaft hole 9b in which the split bearings 7a and 7b are set, here, the shaft hole 9a is fitted into the crank pin 4a.
At this time, as shown in FIG. 3, the opening width H formed by the protruding end 7c of the split bearing 7a and the end of the split surface a located near the other end of the split bearing 7a is the diameter of the crank pin 4a. It is set to be larger than the dimension D. For this reason, the split bearing 7a can be fitted without adjusting the position of the split bearings 7a and 7b. Here, each of the split bearings 7a is set so as to be shifted by about 10 degrees with respect to the split surface a, thereby securing a front opening through which the crankpin 4a can enter and exit. The same applies to the split bearing 7b of the bearing cap 12.

  Thereafter, the other shaft hole 9b is fitted into the crankpin 4a. At this time, as shown by the arrow γ in FIG. 3, the end portions 7c and 7f of the split bearings 7a and 7b protruding from the split surface a of the shaft holes 9a and 9b are replaced with the shaft holes 9a from which the other end of the bearing metal is retracted. , 9b, and the rod body 11 and the bearing cap 12 are abutted on the dividing surface a. Next, the connecting rod 5 is assembled as shown in FIG. 4 by fastening the rod body 11 and the bearing cap 12 with the cap bolt 14.

At this time, the connecting rod body 11 and the bearing cap 12 are displaced in the axial hole radial direction parallel to the split surface a by the end portions 7c and 7f of the split bearings 7a and 7b inserted into the inner surfaces of the shaft holes 9a and 9b. Not regulated.
Due to the method of assembling the connecting rod 5, a positioning member such as a knock pin is not required, and the displacement of the rod body 11 and the bearing cap 12 in the radial direction of the axial hole parallel to the dividing surface a can be performed only by using the divided bearings 7 a and 7 b. Can be regulated. Therefore, cost can be reduced and workability can be improved. In addition, if the opening width H formed by the ends of the split bearings 7a and 7b is set larger than the diameter of the crank pin 4a, the adjustment work of the split bearings 7a and 7b is not necessary when fitting the crank pin 4a. The workability for assembling the connecting rod 5 is improved.

  In particular, as shown in FIGS. 2 to 4, the split bearings 7a and 7b have one end, here, the radial thickness T1 of the ends 7c and 7f, and the diameter of the ends 7d and 7e serving as the other ends. The connecting rod body 11 is thinner than the thickness T2 in the direction, specifically, from the inner peripheral side so that the end is thin, and the thin ends 7c and 7f are positioned on the rotation direction delay side of the crank pin 4a. By setting the shaft hole 9a and the shaft hole 9b of the bearing cap 12, the resistance between the assembled bearing metal 7 and the crank pin 4a can be reduced. That is, when the connecting rod 5 is assembled, if pressure is applied to the split surface b with the split bearings 7a and 7b due to an assembling error or a manufacturing error, the end portions 7c and 7f are pivoted from the adjacent end portions 7d and 7e. There is a risk of projecting inward in the radial direction of the hole and becoming the resistance of the crank pin 4a. However, the end portions 7c and 7f are formed by reducing the thickness T1 of the ends 7c and 7f from the inner peripheral side in advance. It can suppress that it protrudes in an axial hole direction inner side rather than the edge parts 7d and 7e, and can suppress the increase in the resistance of the bearing metal 9 and the crankpin 4a at the time of rotation of the crankpin 4a.

  Note that the connecting rod assembly method of the present invention is not limited to the above-described embodiment, and may be implemented in various ways without departing from the gist of the present invention.

4a Crank pin 5 Connecting rod 5b Large end 9a, 9b Shaft hole (Main body side shaft hole, Cap side shaft hole)
7 Bearing metal 7a, 7b Split bearing 11 Rod body (main body)
12 Bearing cap a Dividing surface between main body and bearing cap b Bearing metal dividing surface

Claims (3)

A method of assembling a connecting rod that is rotatably connected to a crank pin via a bearing metal,
The connecting rod has a bearing cap and a main body that equally divides a shaft hole through which the crank pin is inserted into a semicircular cap side shaft hole and a main body side shaft hole,
The bearing metal is formed from two semicircular split bearings,
The split bearings are respectively connected to the cap side shaft hole and the main body side shaft hole, and a straight line connecting both ends of the split bearing is rotated by a predetermined amount in the circumferential direction of the shaft hole from the split surface of the shaft hole. After setting the crank pin in one of the cap side shaft hole and the main body side shaft hole in which the split bearing is set, the end projecting from the split surface is set to the other split bearing. A connecting rod assembling method, wherein the connecting rod is assembled by being inserted into an inner surface of a shaft hole whose end is recessed. The predetermined amount is set so that an opening width formed by one end of the split bearing protruding from the end of the split surface located near the other end of the split bearing is larger than the diameter of the crank pin. The connecting rod assembling method according to claim 1, wherein the connecting rod is assembled. One end of the split bearing is a thin-walled end that is formed so that the thickness in the radial direction is thinner from the inner periphery than the other end,
The set of connecting rods according to claim 1 or 2, wherein the split bearing is set on the bearing cap and the main body so that the thin end portion is located on the rotation direction delay side of the crank pin. How to attach.

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