JPH0242207A - Connecting rod connecting device - Google Patents

Abstract

PURPOSE:To aim at making a large end part of a link lightweight and at reducing an inertial mass thereof by maximizing the inner diameter of the inner peripheral section of an integral type plain bearing at a part which is orthogonal to an axial line connecting between a small and large end parts of the link. CONSTITUTION:In order to couple a link 25 with a crank shaft 22, an integral type plain bearing 33 is fitted on a large end part 31 of the link, and a crank pin 38 on the crank shaft 22 is inserted into the plain bearing. The inner peripheral part of the plain bearing 33 which receives therein a large end part 31 of the link 25 in association with reciprocation of a piston is maximized at a part which is orthogonal to an axial line connecting between small and large end parts 30, 31 of the link 25. Accordingly, even though it is pulled in the reciprocating direction of the piston so as to be deformed, no chaffing part is presented between the inner peripheral part of the plain bearing 33 and the outer peripheral part of the crank pin, and a sufficient amount of lubrication oil is fed therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a connecting device for a connecting rod, and more particularly to a connecting device for connecting a connecting rod and a crankshaft.

[Prior Art] Generally, in an engine, the large end of a connecting rod is connected to the crank pin of the crankshaft via a large end bearing, and the piston is connected to the small end of the connecting rod via a piston pin. This allows the reciprocating motion of the piston caused by the explosion pressure within the cylinder to be converted into rotational motion of the crankshaft via the connecting rod. Here, a large load is applied to the crank pin of the crankshaft due to the explosion pressure within the cylinder, and at the same time, during high-speed rotation, a large inertial force is applied due to the respective masses of the crank pin itself, the connecting rod, the piston pin, and the piston. . Further, a large load due to the explosion pressure within the cylinder acts on the big end bearing, and a large inertial force based on the respective masses of the connecting rod, piston pin, and piston acts on the large end bearing during high-speed rotation.

By the way, conventionally, the big end of a connecting rod using a flat bearing is divided into two parts, and the flat bearing serving as the big end bearing is also divided into two parts, and these two divided big ends and the flat bearing are connected to each other when cranking. It is attached to the outer circumference of the pin, and the two halves of the large end are joined together by bolting.

In addition, in the morning stand type crankshaft, the undivided large end of the connecting rod is connected via a needle bearing to a crank pin that can be extended vertically to the web.

[Problems to be Solved by the Invention] In the former known engine, the weight of the large end of the connecting rod increases by the weight of the bolts, increasing the inertia weight, so that the former is not suitable for use in high-speed rotation engines. do not have. In addition, in the latter case, since the outer diameter of the needle bearing is relatively large, the shape of the large end of the connecting rod is forced to be large, and the weight of the large end becomes large. The problem was that it was not suitable as a

This invention has been made in view of the problems of the prior art, and its purpose is to reduce the weight and inertial mass of the large end of the connecting rod, and to prevent seizure. The purpose of the present invention is to provide a connection device for a connecting rod that does not require a connecting rod.

[Means for Solving the Problems] In order to achieve the above object, the connecting rod connecting device of the present invention has the following features: A flat bearing is inserted into the large end of the connecting rod, and the large end is connected to the crankshaft. In a connection device for a connecting rod connected to a crank pin, the flat bearing is integrated, and the inner diameter of the inner circumferential portion thereof is the largest at a portion perpendicular to an axis connecting the small end and the large end. It is something that was done.

[The flat bearing inserted into the big end of the connecting rod is an integrated type, so in order to connect the connecting rod to the crankshaft, insert the flat bearing into the big end of the connecting rod and connect it to the crankshaft. It is sufficient to insert the crank pin into the plain bearing.

Furthermore, even if the flat bearing inserted into the large end of the connecting rod is pulled and deformed in the direction of the piston's reciprocating motion, the inner diameter of the inner periphery of the flat bearing will not reach the small end. Since the maximum is at the part perpendicular to the axis connecting the and big end, there is no rubbing area between the inner circumference of the plain bearing and the outer circumference of the crank pin, and there is sufficient lubricating oil between the two. is supplied, and no burn-in phenomenon occurs.

[Example] Embodiments of the invention will be described below with reference to the drawings.

In the motorcycle shown in Fig. 1, the frame 11 has a V
A 4-cylinder engine 12 is mounted, a front wheel 14 is pivotally supported at the front of the frame 11 via a front fork 13, and a steering handle I5 is provided, and the rear of the frame 11 is attached downward by a lever cushion 16. A rear wheel 18 is pivotally supported by the biased rear arm 17. A fuel tank 19 and a seat 20 are attached to the upper part of the frame 11, and a passenger can sit on the seat 20.

As shown in FIG. 2, in the engine 12, a crankshaft 22 is rotatably supported by a crankcase 21, and pistons 24 are installed in cylinder liners 23 provided for each of the four cylinders, two front and rear. It is housed so that it can be reciprocated by the pressure of the explosion. The reciprocating motion of the piston 24 rotates the crankshaft 22 via the connecting rod 25, which in turn rotates the crankshaft 22 through the connecting rod 25, and the crank gear 26, clutch gear 27, . Clutch 28. The rear wheels 18 are rotatable via a transmission or the like.

As shown in FIG. 3, the connecting rod 25 includes a main body 29, a small end 30, and a large end 31. A bearing 32 is press-fitted into the small end 30 of the connecting rod 25, and the piston 24 is connected to the piston 24 via a piston pin pivotally supported by the bearing 32. The large end portion 31 of the connecting rod 25 is integrally formed in an undivided manner, a flat bearing 33 is press-fitted therein, and the large end portion 31 of the connecting rod 25 is connected to a crank pin of the crankshaft 22 as will be described in detail below.

Here, the flat bearing 3 press-fitted into the large end 31 of the connecting rod 25
3 is manufactured according to the manufacturing process shown in FIGS. 4(A) to 4(E). That is, the raw material 33A, which is obtained by cutting a bimetallic material in which white metal, kelmet metal, etc. is applied to the back metal of an iron plate, is cut from FIG. 4(A) to FIG. 4(
After forming into a cylindrical shape as shown in B) and determining the width, the outer periphery is polished to obtain an intermediate molded product 33B. This intermediate molded product 3
3B, as shown in FIG. 4(C), the long axis is Ll.
, is press-fitted into an oblong or elliptical hole mold 34 whose short axis is L2. The intermediate molded product 33B press-fitted into the hole mold 34 is
As shown in FIG. 4(D), the inner diameter portion is subjected to a polling process, and the inner diameter d is finished into a perfect circular shape. That is, the intermediate molded product 33B subjected to the polling process in FIG. 4(D) has a large wall thickness in the vertical direction and a small wall thickness in the horizontal direction. This intermediate molded product 33
By removing B from the hole mold 34, the restriction of the hole mold 34 is removed, and as shown in FIG. The circumferential shape is made into an oval or elliptical shape in which the inner diameter d2 in the horizontal direction is larger than the inner diameter d1 in the vertical direction in the figure, and is further subjected to necessary treatments such as plating to become the plain bearing 33 as a final product. .

When the flat bearing 33 is press-fitted into the perfectly circular inner diameter portion of the large end 31 of the connecting rod 25, as shown in FIG. It is set to be larger than the inner diameter d1 in the direction. That is, connecting rod 2
5, the inner diameter of the inner circumference is the same as that of the connecting rod 2.
d2 is maximum at a portion perpendicular to the axis connecting the small end 3° and the large end 31 of 5. Therefore, when the plain bearing 33 is connected to the crank pin as described later, a large oil clearance is formed between the bearing and the crank pin at the maximum inner diameter 62, resulting in an excessive bearing load. Even when the plain bearing 33 is deformed in the vertical direction under the action of , this clearance in the horizontal direction does not disappear.

The connecting rod 25 is connected to the crankshaft as shown in FIG. That is, as shown in FIG. 5, the crankshaft 22 has an intermediate journal part 35 and wears 36 on both sides thereof integrally formed, and each journal part 37 at both ends, each crank pin 38, and a web 39 are integrally formed. , each crank pin 3 is inserted into a fitting hole 4o provided in a wear 36 integrally formed with the intermediate journal portion 35.
The intermediate journal portion 35 and each journal portion 37 at both ends are pivotally supported by a main bearing 41 formed in the crankcase 21. Further, before each crank pin 38 is press-fitted into the fitting hole 4o of the wear 36 integrally formed in the intermediate journal portion 35 of the crankshaft 22, the large end portion 31 of the connecting rod 25 is press-fitted. Plain bearing 33
It is connected to each crank pin 38 via. Sunawachi,
An undivided large end 31 of the connecting rod 25 and a flat bearing 33 can be attached to each crank pin 38 of the crankshaft 22 . Note that since this engine 12 is V-shaped, two connecting rods 25 can be connected to each crank pin 38. Furthermore, an oil passage 42 is formed in the intermediate journal portion 35 of the crankshaft 22, and an oil passage 43 is formed on the axis of each crank pin 38, so that the oil passage 42 and the oil passage 43 are communicated with each other. There is. Further, an oil passage 44 is formed in the intermediate journal portion 35, and the oil passage 44 allows lubricating oil pumped by an oil pump to be introduced into the oil passage 42 from an oil passage formed in the crankcase 21. Each crank pin 38 has two connecting rods 2
An oil passage 45A and an oil passage 45B respectively corresponding to the flat bearing 33 press-fitted into the large end 31 of 5 are provided, and each of the flat bearings 33 can be lubricated via each oil passage 45A, 45B. .

According to this embodiment, as the engine 12 operates, the piston 24. Connecting rod 25. Crankshaft 22° Crank gear 26. Clutch gear 27. The rear wheel 18 is driven via a clutch 28, a transmission, etc., and due to the reciprocating motion of the piston 24, a flat bearing 33 inserted into the large end 31 of the connecting rod 25 is driven in the direction of the reciprocating motion of the piston 24. Even if the plain bearing 33 is pulled and deformed by the There is no rubbing area between the periphery and the outer periphery of the crank pin 38, and sufficient lubricating oil is supplied between the two, so that seizure does not occur.

Incidentally, in the above-mentioned embodiment, the description has been given of the case where the invention is applied to a type engine, but the present invention can also be applied to an in-line type engine.

[Effects of the Invention] In this invention, since the flat bearing inserted into the large end of the connecting rod is integrated, it is difficult to connect the connecting rod to the crankshaft.
All you need to do is insert a flat bearing into the big end of the connecting rod and insert the crank pin of the crankshaft into the flat bearing, and there is no need for a bolt to secure the big end integrally by bolting as in the conventional example. In addition, the use of flat bearings reduces the overall shape of the large end, which reduces the weight of the connecting rod and reduces the inertial force that acts on the crank pin, flat bearings, etc. during high-speed rotation. This makes it possible to reduce the rotational speed of the engine.

Furthermore, even if the flat bearing inserted into the large end of the connecting rod is pulled and deformed in the direction of the piston's reciprocating motion, the inner diameter of the inner periphery of the flat bearing will not reach the small end. Since the maximum is at the part perpendicular to the axis connecting the and big end, there is no rubbing area between the inner circumference of the plain bearing and the outer circumference of the crank pin, and there is sufficient lubricating oil between the two. is supplied and no seizure occurs, so the service life of the plain bearing can be greatly extended.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a motorcycle to which this invention is applied, Fig. 2 is a plan view showing an embodiment of this invention with main parts cut away, and Fig. 3 is a connecting rod of the embodiment taken out. 4(A) to 4(E) are process diagrams showing the process of manufacturing the large end bearing of the connecting rod in the same embodiment, and FIG.
The figure is a sectional view showing the state of connection between the crankshaft and the connecting rod in the same embodiment. 22... Crankshaft, 25... Connecting rod, 30...
Small end, 31... Large end, 33... Plain bearing, 38...
... Crank pin, di, d2...inner diameter. Patent issuer Yamaha Motor Co., Ltd. agent Patent attorney Art supplies Mikio Figure 2

Claims (1)

[Claims] In a connection device for a connecting rod in which a flat bearing is inserted into a large end of a connecting rod and the large end is connected to a crank pin of a crankshaft, the flat bearing is integrally formed and the inner circumferential portion thereof is integrated. A connecting rod connecting device characterized in that the inner diameter of the connecting rod is maximized at a portion perpendicular to an axis connecting the small end and the large end.