JPH044360A - Structure for tip end section of connecting rod - Google Patents

Abstract

PURPOSE:To facilitate the work of a bearing plate, and thereby reduce the cost by forming a screw hole to which a screw shaft at the tip end section of a connecting rod is freely threaded, in the boss section of the bearing plate which is engaged with a projecting section at the back side of a piston crown section. CONSTITUTION:A boss section 11 projecting downward is formed at the center of a bearing plate 12 in a semi-circular shape in cross section which is engaged with a projecting section 4 in a semi-circular shape in cross section at the back side of a piston crown section 2a. In the second place, a screw shaft 19 formed at the tip end section of a connecting rod 13 is threadedly connected to the screw hole 18 of the boss section 17, so that the desired tip end section of the connecting rod can thereby be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention can be incorporated into the cylinder body of an internal combustion engine or an air compressor, which has a limited height.
- This relates to a connecting rod that can lengthen the rake, particularly the structure of the tip of the connecting rod.

[Conventional technology] Internal combustion engine or air pressure 1? In order to increase the displacement or discharge amount without changing the specifications of the cylinder body of the i-machine, it is economical to lengthen the stroke of the piston. For this reason, in a structure in which the tip of the connecting rod is connected to the piston by a piston pin (see, for example, Jitsuma No. 11164-47958), the crank arm is lengthened and the connecting rod is shortened accordingly. However, in this case, the shorter the connecting rod is, the more the connecting rod will be tilted with respect to the cylinder center axis, and the screw slip will become more pronounced, causing wear on the piston rings, an increase in slapping noise, and a decrease in fuel efficiency. figure.

Therefore, in Japanese Patent Application No. 1999, the applicant has proposed a method in which a receiving plate having a concave portion having a semicircular cross section formed at the tip of the connecting rod is slid onto a convex portion having a semicircular cross section formed on the back surface of the piston crown. A patent application was filed for a connection structure between a piston and a connecting rod that are movably engaged. With this connection structure, the center of oscillation of the connecting rod relative to the piston is closer to the crown surface of the piston compared to conventional ones, and the crank arm can be made sufficiently long without changing the length of the connecting rod. I can do it.

In the case of an internal combustion engine, the weight of the screws 1 or 2 above the center of swing of the connecting rod is lighter, so the impact (slap) on the cylinder due to the swing of the screw 1 is suppressed, and the relationship between the piston ring and cylinder is reduced. The sealing performance of the gap between the parts is stable, the amount of blow-high gas is reduced, and fuel efficiency is improved. The surface pressure on the receiving plate that supports the explosive load from the piston of the connecting rod is reduced, which is advantageous in terms of strength and lubrication.

[Problems to be solved by the invention] In general, connecting rods are processed by forging, but the connecting rod with the double-joint structure shown in above) is different from the conventional one and has a cylindrical or spherical surface. There are various difficulties in forming a thin-walled receiving plate integrally with the tip of the connecting rod by forging, and the cost increases.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a structure for a connecting rod tip that is easy to apply T and can be manufactured at low cost.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention is such that the structure of the present invention is such that the center of the receiving plate having a semicircular cross section is engaged with the convex portion having a semicircular cross section on the back side of the piston crown. A protruding boss is formed, and a screw shaft formed at the tip of the connecting rod is screwed into a screw hole in the boss.

i° Effect] Since the connecting rod main body and the receiving plate that engages with the piston are formed separately by forging or the like, forming and finishing are facilitated. The connecting rod body and the receiving plate are connected with screws.

[Embodiments of the Invention] Fig. 3 is a front sectional view of a connecting structure of a screw I and a connecting rod to which the present invention is applied, and Fig. 4 is a side sectional view of the same. Vis 1-2 shown as an example of a T building engine are bis l
A combustion chamber 3 is formed by providing a recess in the crown surface 2a of the engine, while a known piston ring is attached to the outer peripheral wall, and a mechanical
The interior of parts 1 to 7 is hollow, which is almost the same as the conventional one.

A convex portion 4 having a spherical surface 5 projecting downward is formed on the back surface of the piston crown. The periphery of the convex portion 4 is defined by an annular cavity 6, and the annular cavity 6 is filled with lubricating oil for cooling or supplied from the outside.

The spherical surface 5 of the convex portion 4 is provided with a cavity 5a that holds oil for cooling and lubrication. A bowl-shaped receiving plate 12 is integrally formed at the tip of the connecting rod 13. Spherical recess 1 of receiving plate 12
2a is slidably engaged with the spherical surface 5.

In order to maintain the engagement between the convex portion 4 and the receiving plate 12, the receiving plate 12
An annular presser foot 8 having a spherical concave portion 8a is brought into contact with the back surface of the presser foot 8. The presser foot 8 is supported by a cylindrical nut 9 screwed onto the skirt portion 7. The nut 9 is prevented from loosening by a retaining ring 10 engaged with the mechanisms 1 to 7.

The tip end shaft portion of the arm of the crankshaft 16 is connected between the semicircular recess 14a of the base end portion 14 of the connecting rod 13 and the semicircular recess 15a of the bearing cap 15. The configuration of the proximal end of the connecting rod 13 is similar to that of the conventional one. The receiving plate 12 at the tip of the connecting rod 13 engages with the convex portion 4 on the back side of the screw crown, and the connecting rod 13 swings when the crankshaft 16 (represented by the axis) rotates.

According to the above structure, compared to the conventional structure in which the tip of the connecting rod is connected to the piston by a piston pin, the center of swing a of the connecting rod 13 is arranged very close to the piston crown surface 2a. be done. In other words, the swing center a and the piston crown surface 2
Since the dimension p between the
The stroke of the cylinder 2 is increased, and the displacement is greatly increased without changing the height h of the cylinder body 21.

By the way, if necessary, the reduction in the dimension p between the piston crown surface 2a and the swing center a can be distributed to the extension of the arm length r of the crankshaft 1G and the length Q of the connecting rod 13. and Q j,
/ r value can be maintained as before, the inclination (maximum inclination angle) of the connecting rod '13 when the crankshaft '16 is rotated 1/4 from the top dead center of the piston can be maintained as before, and the screw 1-
Slap is suppressed.

FIG. 1 is a side sectional view of the distal end of the connecting rod, showing an exploded view of a connecting rod main body and a receiving plate according to the present invention, and FIG. 2 is a front view thereof. According to the present invention, the boss portion 17 protruding downward is integrally formed at the center or bottom of the receiving plate 12, which includes the spherical recess 12a and the spherical convex portion 12b, and the boss portion 17 has a screw hole. 18 are provided. Preferably, a flat surface 17a is formed on the outer peripheral surface of the boss portion 17 and has a substantially hexagonal cross section for engaging a tool.

On the other hand, a threaded shaft 19 is integrally formed on the connecting rod main body 13a and projects in the longitudinal direction from a distal end surface 19a.

By configuring the connecting rod main body 13a and the receiving plate 12 separately, forming by forging and machining of the recessed portion 12a and the convex portion 12b are made very easy.

As shown in FIG. 2, the connecting rod main body 13a and the receiving plate 12 are
The threaded shaft portion 19 of the connecting rod body 13a is inserted into the threaded hole 1 of the receiving plate 12.
8, and connect the tip end surface 19a of the connecting rod body 13a to the receiving plate 1.
The second boss portion 17 is brought into contact with the end surface 17b of the second boss portion 17 and is integrally coupled.

In the above embodiment, the receiving plate 12 at the tip of the connecting rod supports the spherical convex portion 4 of the piston with the spherical recess 12a, but the present invention is not limited to this. The receiving plate of the piston may support the shaft portion of the piston (a convex portion having a semicircular cross section) with a concave portion having a semicircular cross section (cylindrical surface parallel to the crankshaft).

[Effects of the Invention] As described above, the present invention forms a downwardly protruding boss portion at the center of a receiving plate having a semicircular cross section that is engaged with a convex portion having a semicircular cross section on the back side of the piston crown, and The threaded shaft formed at the tip of the rod is screwed into the screw hole in the boss part, and the connecting rod is divided into a main body and a receiving plate that is engaged with the screw 1. Forming by forging the plate and machining the concave and convex parts of the receiving plate are facilitated, which helps reduce costs.
.

By using an upper die that forms concave parts and a lower die that forms convex parts in the @ structure of the receiving plate, there is no wasted material due to mold separation, and the cutting edge F allowance for machining can be reduced. It becomes less.

It becomes possible to use a material for the receiving plate that has excellent wear resistance, heat resistance, and lubricity for engagement with the piston.

[Brief explanation of the drawing]

Fig. 1 is an exploded side sectional view showing the structure of the connecting rod tip according to the present invention, Fig. 2 is a front sectional view of the connecting rod tip, and Fig. 3 is the connection structure of the screw ring and the connecting rod. FIG. 4 is a side sectional view of the same. 4: Convex portion 12: Receiving plate 12a; Concave portion 13: Connecting rod
17: Boss part 18: Drilled hole 19: Screw shaft Fig. 1 (0) Fig. 1 (1)) Fig. 2 Fig. 1 [ Fig. 3E Fig. 4

Claims (1)

[Claims] A boss part protruding downward is formed at the center of a receiving plate with a semicircular cross section that is engaged with a convex part with a semicircular cross section on the back side of the piston crown, and a screw shaft formed at the tip of the connecting rod is connected to the boss part. The structure of the connecting rod tip is characterized by being screwed into a screw hole.