JPH07646Y2 - Rocker arm - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a loker arm, and more particularly to a rocker arm having improved mounting means for a valve or push rod pressure contact pin.

[Prior Art] For intake and exhaust of an engine, for example, as described in Japanese Utility Model Publication No. 58-122710, the vertical movement of a push rod driven by a cam is used to open and close an intake or exhaust valve via a rocker arm. I am doing it. The outline of this valve operating mechanism will be described with reference to FIG. 10 attached herewith. Adjusting screws 3 and 4 are attached to both arms of a rocker arm 2 pivotally supported on a rocker arm shaft 1. The adjusting screw 3 is in contact with the valve 6 via the cup 5 attached to the tip of the adjusting screw 4, and the tip of the adjusting screw 4 is in contact with the push rod 8 which moves up and down in response to the cam 7. In the figure, 9 is a valve spring, 10 is an upper spring seat, and 11 is a lifter provided at the upper and lower ends of the push rod 8, respectively.

The adjusting screws 3 and 4 are for adjusting the valve clearance, and FIG. 12 shows the screw 3,
It is a locking nut for 4. By the way, the valve clearance can be adjusted by adjusting one of the adjusting screws 3 and 4, so that one in which the pin is fixed to the rocker arm 2 by press fitting, welding, brazing, etc. without screwing one is there.

However, the screw-shaped one has a problem that the number of parts and the number of processing steps are increased and there is a risk of loosening the screw. Further, among the pin type, it is difficult to control the tightening margin of 8 by the press-fitting means,
In addition, loosening is likely to occur during use, and there is a risk of breaking the tip portion of the rocker arm due to excessive pressure input. Further, the welding or brazing means has a problem that deterioration of the welded or brazed portion causes troubles and that the contact surface hardened by heat treatment is tempered and worn.

[Purpose of device]

The present invention has been made focusing on the above problems,
The purpose of the present invention is to provide a rocker arm in which a valve that is mounted on a rocker arm or a pin that comes into pressure contact with a push rod has high dimensional accuracy and dimensional stability after mounting with a simple mounting means and that does not easily fall out or rattle. I am trying.

[Constitution of device]

The rocker arm of the present invention for achieving the above object is provided with a hole into which a push rod or a pin for press-contacting a valve is fitted in the main body of the loker arm, and the hole is provided at the back of the hole at the outside of the hole. A widening expanded portion is formed, and a deformed portion made of metal that is plastically deformed by press fitting is provided at the tip of the pin.The expanded portion is press-fitted into the hole and plastically deformed into the expanded portion. The pin is coupled and fixed to the rocker arm body by the deformed portion that has entered the widening portion.

It is preferable that the pin and the hole for mounting the pin are manufactured to have a fitting degree such as a clearance fitting. Further, it is preferable that the expanding portion formed in the deep part of the hole has a shape that easily penetrates into the expanding portion by a metal flow generated by plastic deformation of the deformed portion provided at the tip of the pin. ,
It can be provided in various forms, such as a plurality of expanding portions provided in the shape of a bonnet.

The shape of the plastically deformable portion of the pin provided on the rocker arm is preferably manufactured to have a crushing allowance that is compatible with the expanded portion. The pin to be used usually has a circular cross section, but since the present invention is mounted by pushing, the pin can be applied to other shapes, such as a square shape.

The material of the pin is usually a steel material such as S20, but it is preferable to use a material that easily causes metal flow, for example, a soft metal such as copper or aluminum, for the portion that causes the plastic deformation. The soft metal and the steel material can be joined by means such as mechanical fitting, welding, brazing and the like.

The above-mentioned configuration in which the pin is attached to the rocker arm by causing a metal flow in the hole having the widened portion enables firm assembly by a simple processing means.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings according to an embodiment.

FIG. 1 is a sectional view of an essential part of the rocker arm of the first embodiment, in which a hole-shaped bottom portion of the hole 15 formed in the rocker arm 2 is provided with a ring-shaped expanded portion 17 which is expanded in the circumferential direction. The pin 18 is attached in such a state that the tip of the pin 18 is inserted into the expanding portion 17.

The spherical portion 19 of the pin 18 is pressed against a valve or push rod (not shown), usually via a cup, a lifter or the like, and can be formed in a usual shape. Therefore, in order to improve wear resistance, the front surface on the tip side of the spherical portion 19 is quenched, and in this embodiment, as shown in FIG. 2, the pin body 20 and the fixing portion 21 made of copper or the like that causes metal flow are formed. Are attached by mechanical fitting so as to have mechanical strength such as wear resistance and easy plastic deformability. Note that this joining can also be performed by other means such as welding or brazing means.

Next, as shown in FIGS. 2 to 4, the pin 18 is attached to the rocker arm 2.
The procedure for mounting will be described. Figure 2 shows the pin 18 before deformation.
The state where (diameter D) is inserted into the hole 15 (diameter D + α) of the rocker arm 2 is shown. In the case of a truck engine, for example, the above-mentioned α is usually about 0 to 0.05 mm, but naturally, it can be appropriately determined according to actual circumstances.

The deformed portion 22 has a shape projecting in a thread bottom shape at the tip of the pre-deformation pin 18 on the side where the metal flow is caused, and this portion constitutes a crushing margin. The pin pushing jig 23 is used by covering the spherical portion 19 of the pin 18 as shown in FIG.
As shown in the figure, the surface of the jig 23 that contacts the spherical portion 19
It may have a U-shaped cross-sectional shape that contacts the tip of 19, or may have an appropriate contact condition such as a conical shape that makes a ring-shaped contact as shown in FIG.

When the pin 18 is pushed in by the jig 23, as shown in FIG. 4, the deforming portion 22 causes a metal flow in the direction of the arrow due to the pressing force to enter the expanding portion 17 and The tip flat portion 24 of the above is pressed against the bottom of the hole 15 to fix the pin 18 to the rocker arm 2. In this embodiment, when the pin 18 having a diameter of 8 mm is used, and the height h of the ring-shaped expanding portion 17 is set to 1.5 mm, when S20 is used as the material of the fixing portion 21 that causes the metal flow, it is pushed in. A sufficient pull-out prevention force was generated when the load was 150 to 200 kg and the pushing load when using copper was about 100 kg.

FIG. 5 shows a second embodiment, in which a ring-shaped wedge-shaped projection 25 is provided on the bottom of the hole to facilitate the metal flow.
The flesh of the deformed portion 22 of the pin 18 divided by the protrusion 25 is guided toward the expanded portion 17 along the slope.

FIG. 6 shows a third embodiment, and the expanding portion 17 of this embodiment is formed in a ring shape extending in the pushing direction of the pin 18. The deformed portion 22 formed at the tip of the pin 18 before deformation in this embodiment has a thread bottom shape similar to that of the pin 18 in the first embodiment, but has an inner circumference to facilitate entry into the expanded portion 17. Is slightly inclined. By pushing the pin in, the pin 18 is deformed in the order of FIG. 7 and FIG.
As shown in the figure, it enters the expanding portion 17 and engages / fixes.

FIG. 9 is a perspective view in which the shapes of the hole 15 and the expanded portion 17 of the third embodiment using the pin 17 having a square cross section are seen through. The present invention can be effectively applied to shapes other than the circular shape. In this case, it is preferable that the crush margin, that is, the deformed portion 22 is also formed in a shape that matches the expanded portion 17 of FIG.

[Effect of device]

As described above, in the rocker arm of the present invention, the expanded portion into which the deformed portion provided on the pin is plastically deformed and fitted is inserted into the hole into which the push rod or the valve pressure welding pin provided in the rocker arm body is fitted. Since it is provided at the bottom of the hole, the pin mounted on the rocker arm is firmly fixed in place with high dimensional accuracy and dimensional stability by simple processing and mounting means to engage / fix and remove. As a result, it is possible to prevent the occurrence of depression and backlash during use, and it is also possible to achieve the effect that the cross-sectional shape of the pin does not need to be circular as in the conventional case.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a rocker arm of the first embodiment, FIGS. 2 to 4 are explanatory views of mounting the rocker arm of FIG. 1, and FIG. 5 is a sectional view of an essential part of the second embodiment. 6 to 8 are sectional views of the essential parts of the third embodiment, FIG. 9 is a perspective view of the pin hole of the fourth embodiment seen through, and FIG. 10 is an explanatory view of a conventional valve operating mechanism. 2 ... rocker arm, 6 ... valve, 8 ... push rod, 15 ... hole, 17 ... expansion part, 18 ... pin, 22 ... deformation part.

Claims (1)

[Scope of utility model registration request] 1. A rocker arm main body is provided with a hole into which a push rod or a pin for press-contacting a valve is fitted, and an expanding portion is formed at the inner part of the hole to expand to the outside of the hole. A deformable portion made of metal that is plastically deformed by press-fitting is provided in the portion, and the expanding portion causes the deforming portion that is press-fit into the hole and plastically deformed to enter the expanding portion, and the deforming portion that has entered the expanding portion causes the pin to expand. A rocker arm that is fixed to the rocker arm body.