JPH01158217A - Sliding member of internal combustion engine - Google Patents

Abstract

PURPOSE:To make a sliding member light-weighted to operate at a high speed so as to aim at improvement in its durability by applying Ni plating on the sliding face of a sliding member made of titanium or titanium alloy, forming an uneven face on its surface by shot peening and applying fluorine group resin coating on the same. CONSTITUTION:Ni plated layers P1, P2 are formed by plating on a rod 13 and the side surface 10a of a cap 14 which form the large end portion 10 of a connecting rod 5 made of titanium or titanium alloy and arranged at a crank shaft. Uneven surfaces P11, P21 are formed by shot peening on these surfaces and fluorine group resin coating layers C1, C2 are formed thereon. Accordingly, the adhesive strength of fluorine group resin coating layer is increased and also sliding performance, conforming performance and the durability of the connecting rod 5 are improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to sliding members used in internal combustion engines.

(Prior art) Materials used in internal combustion engines that have sliding surfaces are required to have heat resistance and wear resistance, so conventionally, materials made of iron-based alloy steel with carburized surfaces were used. It had been.

(Problem to be Solved by the Invention) However, the above-mentioned materials are becoming insufficient as members for connecting rods, etc. used in recent high-speed internal combustion engines, and lighter materials are being developed. There is a need for a sliding member that has excellent heat resistance and wear resistance.

Titanium or titanium alloys are suitable materials for such uses, but these titanium materials have the disadvantage of accelerating the wear of mating parts due to their high galling properties.To improve this, the surface of the titanium material Even if Ni plating is applied to the surface, the Ni plating layer has the drawback of being relatively easily worn and peeling off.

Therefore, it has been desired to obtain a member that has good sliding properties while retaining the advantages of titanium material such as light weight and heat resistance.

(Means for Solving the Problem) The present invention has been made in view of the above circumstances to solve the problem, and the present invention provides a means for solving the problem on the sliding surface of a sliding member made of titanium or titanium alloy. It is characterized in that Ni plating is applied, shot beaning is applied to the surface of the N] plating layer to form an uneven surface, and then a fluororesin coating is applied.

(Function) Since the above means is used, fine irregularities are formed on the surface of the Ni layer by shot peening, the adhesion of the resin coating layer is improved, and peeling of the resin layer is prevented.

Furthermore, compressive residual stress is generated on the surface of the Ni layer by shot peening, and the fatigue strength of the N1 layer is improved, so that the peeling resistance of the core layer can be improved. The fluorine-based fat layer is
In addition to acting as a sliding member with wear resistance, it also provides a slight buffering effect and can prevent galling or wear even if there is a minute step on the sliding surface.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cutaway of the main part of a V-type 4-cylinder 4-cycle engine, and the present invention is implemented at the large end of the connecting rod of the engine, and between two adjacent large ends and between the large end. This improves the sliding properties between the crank web and the crank web.

In the figure, reference numeral 1 is a crankcase, 2 is a crankshaft, and 3 is a cylinder. Only two of the cylinders 3 on one side are shown. 4 is a piston slidably fitted in the cylinder 3; 5 is a connecting rod that transmits the reciprocating motion of the piston 4 to the crankshaft 2; and 6 is a group of cam gears that transmits the rotation of the crankshaft 2 to the camshaft 7. The present invention is implemented in the above-mentioned connecting rod 5.

Two connecting rods 5 are connected to the left and right crank pins 2a, 2a of the crankshaft 2, and their large ends 10 are in contact with each other, and the connecting rods 5 are connected to the side surface 2b of the crank web.

2b, and these adjacent connecting rods 5 are connected to respective pistons 4 of two cylinders arranged with a predetermined included angle.

As shown in FIG. 2, the connecting rod 5 has a large end IO connected to the crankshaft 2, a small end 11 connected to the piston 4 via a piston pin, and both ends 1011.
It is composed of a trunk 12 that connects 1 to 1. The large end IO is constructed by fixing the cap 14 with bolts l-5 to the open side of the rod 13 in which the small end 11 and the trunk 12 are integrated, and the inner peripheral surface thereof has a white A semi-circular bearing metal (not shown) made of a soft material such as metal is fitted.

The connecting rod 5 is made of titanium or a titanium alloy (TI-6AI-4V), and the side surfaces 10a of the rod 13 and cap 14 forming the large end are plated with Ni as shown in FIG. The Ni plating layers PI and P2 are formed, and the surface thereof is shot peened to form a finely uneven surface Ps+q P21, and on top of that, a fluororesin coating layer C is formed.
1, C2 is formed. The above Ni plating layer PI, P
Preferably, the thickness of layer 2 is about 20 pm, and the thickness tl of the fluororesin coating layers C1 and C2 is about 60 μm, and if it is too thick, it will easily peel off.

In the above-mentioned connecting rod 5, the sliding properties are improved by the resin coating layers C and C2, and galling, seizure, etc. are prevented from occurring, and furthermore, the resin coating layers C and C2
Because it has low rigidity and moderate flexibility, it has good conformability, and even when local surface pressure (edge load) is applied,
By deforming the coating layer C+ %' C2, the surface pressure applied to the titanium or titanium alloy base material can be reduced. By impregnating this coating layer with a lubricant such as molybdenum disulfide, the coefficient of dynamic friction can be reduced and durability can be further improved.

For example, in the case of a two-part connecting rod 5 as shown in FIG. 2, even if the rod 13 and the cap 14 are butted together with high precision so that they are flush, there is a 6jI11 as shown in FIG. It is unavoidable that a gap t0 of some degree will occur. However, in the case of the connecting rod 5 of the present invention, the thickness of the side coating layers CI and C2 is 1. is set to about 60 JIm, so even if lateral pressure is applied from the adjacent connecting rod member or crank web Z, the coating layer CI on the side of the rod 13 or cap 14 that protrudes laterally is deformed and the coating is If the thickness of the layer C2 is slightly reduced, the adjacent component 2 will come into contact with the coating layer C2 on the other side.

Therefore, extreme uneven contact can be prevented.

From the above, the connecting rod 5 of the present invention has increased wear resistance and durability against uneven contact. This is shown in Figure 4.
As shown in FIG. 5, this is also clear in comparison with the conventional one.

Figure 4 shows the sliding time leading to seizure, and Figure 5 shows the load at which seizure occurs, using experimental results for connecting rod A made of conventional carburized steel and connecting rod B having a fluororesin coating layer. Seizure starts in about 10 minutes under a load of about 27 kg, but connecting rod B does not seize for more than 50 hours and can withstand a load higher than the above load.

Also. Even in experiments in which the resin coating layer was slid without oil, due to the presence of the Ni layer, the seizure time was longer than when the titanium material was directly slid, and the seizure was on the same level as when using carburized steel. It was time.

(Effects of the Invention) As described above, the present invention improves sliding properties, conformability, etc. that were lacking in titanium materials by coating with fluororesin, and therefore lightweight titanium materials are used as moving members with sliding parts. This makes it possible to expand the use of titanium materials as parts that need to be lightweight in order to increase speed. In addition, the sliding surface of the titanium material was N1 plated, and the surface of the N1 plating layer was shot peened to form an uneven surface, and then the fluorine resin coating was applied. In addition to increasing the adhesion strength of the coating layer and improving the peeling resistance of the coating layer from the former layer, shot peening generates compressive residual stress on the surface of the Ni layer and improves the fatigue strength of one layer. The peeling resistance from the titanium material of the N1 layer is improved, improving the durability of the connecting rod.

In addition, especially in parts such as the large end of connecting rods where it is unavoidable to have a step on the sliding surface, uneven contact at the step can be prevented by the cushioning properties of the resin coating layer.
It is possible to prevent wear and impact on the stepped portion and the members that come into sliding contact therewith.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an internal combustion engine having a connecting rod according to the present invention, Fig. 2 is an exploded perspective view of the connecting rod, Fig. 3 is a sectional view of the sliding part, and Figs. 4 and 5 show performance performance. It is a comparison diagram. Pl, P2... N1 plating layer Pl, P21... uneven surface C,, C2... fluororesin coating layer stack 1 Fig. 2 Fig. 41 Ru

Claims (1)

[Claims] The sliding surface of a sliding member made of titanium or titanium alloy is plated with Ni, the surface of the Ni plating layer is shot peened to form an uneven surface, and then a fluororesin coating is applied. Sliding parts of internal combustion engines.