JPS6257804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a push rod used in a valve train of an internal combustion engine.

[Conventional technology] Conventional push rods have been made of SC steel, which has excellent strength, but is extremely heavy, which increases the inertia of the valve train, making it difficult to increase the speed of the engine. This has the disadvantage of increasing the jump and bounce associated with this.

In order to overcome such drawbacks,
Japanese Patent No. 113713 proposes a push rod in which a cylindrical body is made of reinforcing fibers, metal pressing members (rod ends) are fitted to both ends of the rod, and the upper structure is bonded with a structural adhesive.

However, in such a push rod, in order to further reduce the weight of the rod and increase the wear resistance of the pressing member in response to higher speeds of the engine, the pressing member is made of ceramic, which is lighter than steel and has excellent wear resistance. However, if a ceramic pressing member is simply bonded to a reinforcing fiber cylindrical body with adhesive, as in the case of the above-mentioned push rod, it will be heated to about 160 to 200°C during engine operation. There is a possibility that a peeling phenomenon may occur at the radial joint surface between the two members due to the difference in thermal expansion between the two members.

On the other hand, Japanese Utility Model Application Publication No. 55-78704 proposes a push rod in which a holding protrusion is formed at both ends of a metal shaft tube body, and a ceramic end fitting (rod end) is fixedly secured by caulking.

However, in such a push rod, the end fitting is made of ceramic in order to reduce the weight in order to adapt to the higher speed of the engine.
It is conceivable to make only the tube body made of carbon fiber reinforced resin, but since it is impossible to form holding edges for caulking at both ends of the tube body due to the nature of the material, it is possible to make only the tube body made of carbon fiber reinforced resin. A join cannot be performed.

Furthermore, even if members with significantly different coefficients of thermal expansion, such as ceramic members and carbon fiber-reinforced resin members, are directly joined together by caulking, if they are heated to high temperatures as described above, Due to the difference in thermal expansion between the two members, the caulked portion may become loose, or a large thermal load may be applied to one of the members, causing damage.

Furthermore, if the caulked portion loosens and causes play, there is a risk that the ceramic end fitting will be immediately damaged by the mechanical impact force, and holding edges must be formed at both ends of the metal shaft tube body. The pipe body is limited to a hollow material, which may reduce the degree of freedom in designing the push rod and valve mechanism.

Furthermore, Japanese Utility Model Application Publication No. 53-82606 proposes a piston in which a heat-resistant coagulant is injected and solidified into a space formed between a fitting portion of a ceramic piston head portion and an aluminum piston body. However, since not only the inner and outer circumferential wall surfaces of the head portion and the piston body but also the inner and outer end surfaces are solidified, the heat of both members increases in the radial direction between the inner and outer end surfaces as the temperature increases during engine operation. There is a risk that a peeling phenomenon may occur due to the difference in expansion, and the circumferential wall of the inlet end of the fitting hole of the head portion and the base end of the fitting protrusion of the piston body are directly and tightly fitted. Since this tight fitting part applies a radial tensile force to the head part due to the difference in thermal expansion of the piston body, there still remains the problem that the head part is easily broken, and such a structure cannot be applied to push rods. Can not.

[Problems to be Solved by the Invention] The present invention was invented in view of the above-mentioned drawbacks, and the push rod body is made of carbon fiber reinforced resin, the rod end is made of ceramic, and the push rod body is made of carbon fiber reinforced resin. The rear end recesses of the ceramic rod ends are fitted into the respective ends of the push rod body through a cylindrical elastic member, and both end surfaces of the push rod body and the inner end surfaces of the rear end recesses of each of the rod ends are brought into contact with each other in a non-adhered state. , by bonding the outer circumferential surface of both ends of the rod body to the inner circumferential surface of the elastic member, and the outer circumferential surface of the elastic member and the inner circumferential surface of the rear end recess of each rod end, respectively. radial tensile force due to thermal expansion of both end surfaces of the push rod body is prevented from being applied to the inner end surface of the push rod body, and
It also prevents the peeling phenomenon caused by the difference in thermal expansion that occurs when adhesive is applied and fixed between the two, and the elastic member prevents thermal strain in the radial direction of the push rod body due to the difference in thermal expansion between the push rod body and the rod end. The weight of the push rod is reduced without compromising its strength.
It reduces jumps and bounces that occur when the inertia of the valve train increases during high-speed engine operation, and prevents damage to the engine's operating timing and valve train components, and also prevents contact with other valve train components. As mentioned above, the rod end is made of ceramic to provide wear resistance and
The objective is to provide a push rod that has improved durability and productivity and is suitable for mass production.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention includes a push rod main body made of carbon fiber reinforced resin with
The rear end concave portion of each ceramic rod end is fitted through a cylindrical elastic member, and both end surfaces of the push rod body and the inner end surface of the rear end concave portion of each rod end are brought into contact with each other in a non-adhered state, and the rod body The outer circumferential surface of both ends of the rod end, the inner circumferential surface of the elastic member, and the outer circumferential surface of the elastic member and the inner circumferential surface of the rear end concave portion of each rod end are bonded to each other.

[Function] Inner end surfaces 24, 34 of the rear end recess of each rod end
This prevents the application of radial tensile force due to thermal expansion of both end surfaces 13 and 14 of the push rod main body 1, and also prevents the peeling phenomenon that would occur when adhesive is applied between the two and fixed. The cylindrical elastic member 4 absorbs and alleviates thermal strain in the radial direction of the push rod body 1 due to the difference in thermal expansion between the push rod body 1 and the rod ends 2 and 3.

[Embodiments of the invention] Hereinafter, one embodiment will be described with reference to the drawings.

1 is the rod body of the push rod, with a specific gravity of approximately
It is made of a carbon fiber reinforced resin material that is lightweight (about 1.7 mm), has high strength, and has a high modulus of elasticity.

2 and 3 are made of a ceramic material having a thermal expansion coefficient of, for example, about 6× ^10-6 /°C and a specific gravity of about 3.0, and are sliding portions 21 formed in arc-shaped concave portions and convex portions, respectively. , 31, and rear end recesses 23, 33 into which the ends 11, 12 of the rod end body 1 are inserted are formed inside the rear ends of the shaft parts 22, 32.

Reference numeral 4 denotes a cylindrical elastic member fitted between the inner circumferential surface of the rear end recesses 23 and 33 of the rod end and the outer circumferential surface of each end portion 11 and 12 of the rod body, and is preferably made of hard rubber. .

Then, no adhesive is applied between the end surfaces 13, 14 of the rod body 1 and the inner end surfaces 24, 34 of the rear end recesses 23, 33 of the rod ends 2, 3, so that they abut in a non-adhered state. , the joining surfaces of the outer peripheries of each of the members, more specifically, the outer periphery of the ends 11 and 12 of the rod body, the inner periphery 41 of the elastic member 4, and the outer periphery 42 of the elastic member 4 and the rod end 2. , 3, the inner peripheral surface 2 of each rear end recess 23, 33
3a and 33a are each coated with an appropriate thermosetting adhesive and bonded together.

In the push rod constructed as described above, the rod body 1 except for the rod ends 2 and 3 made of ceramic material is made of carbon fiber reinforced resin material, so it is significantly lighter than the conventional push rod made of steel. This makes it possible to reduce the inertial force of the valve train, thereby significantly improving the performance against jumps and bounces that occur as the engine speeds up, as described above.

In addition, since the cylindrical elastic member 4 is interposed at the joint between the ends 11 and 12 of the rod body and the rear end recesses 23 and 33 of the rod ends 2 and 3, the coefficient of thermal expansion during operation is 35 to 45 × Rod body 1 has a larger coefficient of thermal expansion than rod ends 2 and 3 at ^10-6 /°C.
Even if thermal expansion occurs, it is absorbed and relaxed by the elastic member 4, so that the rod ends 2 and 3, which are made of ceramic material with an extremely small coefficient of thermal expansion of, for example, 6 x ^10-6 /°C, will not be damaged. There isn't.

Furthermore, since each end surface 13, 14 of the rod body 1 and the inner end surface 24, 34 of each rear end recess 23, 33 of the rod end 2, 3 are in contact with each other in a non-adhered state, the inner end surfaces 24, 34 has each end face 13,1
4 is prevented from being applied in the radial direction due to thermal expansion, and also the peeling phenomenon caused by thermal expansion that occurs when an adhesive is applied and fixed between the two is also prevented.

Further, since the expansion and contraction of the rod body 1 due to thermal expansion in the axial direction is self-adjusted by the rod body 1 itself, no tensile force due to thermal expansion from the rod body 1 is applied to each rod end 2, 3.

Furthermore, since the rod ends 2 and 3 are made of ceramic material and have excellent wear resistance, the durability of the sliding parts 21 and 31 where each end slides with other related parts of the valve mechanism, such as the rocker arm and cam, is improved. It has the effect of improving significantly.

Furthermore, since the rod main body 1 is made of a carbon fiber reinforced resin material having high strength and high modulus of elasticity, it is hardly inferior in strength to conventional push rods made of steel.

[Effects of the Invention] As described above, in the push rod according to the present invention, the rear end recesses of the ceramic rod ends are fitted into both ends of the push rod main body made of carbon fiber reinforced resin through cylindrical elastic members, and the push rod main body is made of carbon fiber reinforced resin. and the inner end surface of the rear end concave portion of each rod end are brought into contact with each other in a non-adhered state, and the outer peripheral surface of both ends of the rod body, the inner peripheral surface of the elastic member, the outer peripheral surface of the elastic member, and the outer peripheral surface of each rod end are brought into contact with each other in a non-adhered state. Since the inner circumferential surfaces of the rear end recesses are bonded to each other, the following effects can be obtained.

First, both end surfaces of the push rod main body and the inner end surfaces of the rear end recesses of the respective rod ends are brought into contact with each other in a non-adhered state, and the outer peripheral surfaces of both ends of the rod main body, the inner peripheral surface of the elastic member, and the outer peripheral surface of the elastic member are brought into contact with each other in a non-adhered state. and the inner peripheral surface of the rear end recess of each rod end, so that a radial tensile force is applied to the inner end surface of the rear end recess of each rod end due to thermal expansion of both end surfaces of the push rod body. At the same time, it is also possible to prevent the peeling phenomenon caused by thermal expansion that occurs when an adhesive is applied and fixed between the two, and the elastic member prevents the peeling phenomenon of the push rod main body and the rod end due to the difference in thermal expansion between the push rod main body and the rod end. Since it can absorb thermal strain in the radial direction, it has the effect of preventing damage to the ceramic rod end and providing a durable and reliable push rod.

The push rod body is made of carbon fiber reinforced resin and the rod end is made of ceramic, making it possible to reduce weight without sacrificing strength compared to conventional steel push rods, reducing the inertia of the valve train during high-speed engine operation. This has the effect of reducing jumps and bounces associated with increased force, thereby preventing damage to engine operating timing and valve train components.

Furthermore, since the rod end, which operates in constant contact with other valve train components, is made of ceramic, its wear resistance and durability are improved, and a reliable rod end can be provided.

In addition, since a cylindrical elastic member is simply interposed between the push rod main body and the recessed portion at the rear end of the rod end, the push rod is easy to manufacture, improving productivity, and providing a push rod suitable for mass production. There is an effect that can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a front view showing an embodiment of the present invention;
3 are partially enlarged vertical cross-sectional views showing essential parts of the same embodiment. 1: Rod body, 2, 3: Rod end, 4:
Elastic member, 21, 31: sliding portion, 23, 3
3: Rear end recess.

Claims (1)

[Claims] 1 Rear end recesses of ceramic rod ends are fitted into both ends of a push rod body made of carbon fiber reinforced resin through cylindrical elastic members, and both end surfaces of the push rod main body and inner end surfaces of the rear end recesses of each of the rod ends are fitted. are in contact with each other in a non-adhered state, and the outer circumferential surfaces of both ends of the rod body are bonded to the inner circumferential surface of the elastic member, and the outer circumferential surface of the elastic member and the inner circumferential surface of the rear end concave portion of each rod end are bonded, respectively. Pushyurotsudo.