JP2010522301A - Rocker arm with integral internal oil path - Google Patents

Abstract

  A rocker arm and a method of manufacturing the same are disclosed, wherein the rocker arm is manufactured in two halves that are generally symmetrical about a central plane. The mating surfaces of one or both rocker arm halves are provided with a groove, which becomes a passage during assembly, which can follow any desired passage of lubricant and / or reduce mass And / or increase in structural rigidity. The two halves are preferably joined together by metallurgical brazing or by other chemical or mechanical means.

Description

  The present invention relates to a rocker arm for an internal combustion engine having an internal oil passage and a method for manufacturing the same. In particular, the present invention relates to an improved rocker arm comprising an internal oil passage formed by joining together a plurality of prefabricated parts (sections) comprising an oil passage as at least one integral feature.

  Conventional methods of manufacturing rocker arms generally include pressing or casting procedures. Thereafter, the formed part (section) is processed to remove material by machining, for example drilling, milling, etc. to form an oil passage (oil passage) in the rocker arm. Such methods, such as machining, drilling, milling, etc., require material removal to form the necessary oil passages. In addition, the passages thus formed often have low dimensional shapes and placement accuracy. Also, oil passages formed by prior art drilling or machining must in practice contain straight lines and be of a size that is compatible with the drilling process and provide optimal advantages It cannot take the form of a “worm” -like groove formed to do. In addition, to obtain deep holes, for example, holes with a depth greater than about 10 drill diameters, it is necessary to use a time consuming and relatively expensive drilling process, ie gun drilling. is there. Manufacturing to pre-manufacture parts and resulting products with oil passages that are precisely formed and precisely positioned, and to join the parts to form a finished rocker arm, in order to save cost and time The method is advantageous.

  The novel rocker arm of the present invention is characterized by joining prefabricated parts (sections) of sintered metal particles, generally two halves symmetrical about a central plane, to one or both halves. The mating surfaces are provided with grooves that form one or more passages for oil during assembly. The resulting product was found to result in a significant reduction in mass and increased structural rigidity. Preferably the prefabricated parts of the powder metal composition are joined together by any known convenient technique, for example by metallurgical brazing or chemical or mechanical means.

  The rocker arm according to the invention, consisting of separate mating parts, preferably two parts prefabricated, is advantageously formed, for example, preferably of powder metal and provided in one or both mating parts. Are manufactured by brazing together such parts having a plurality of grooves in a furnace. Additional machining or drilling to form the internal passage is avoided.

  A jet of air or water is applied to the molten metal stream and the resulting metal particles are collected, sieved, and atomized by an annealing method. During processing, powdered metal particles containing a mixture of different metals can be made compact, for example by pouring metal powder into a die cavity shaped as a finished part, usually at room temperature, and then applying pressure from above and below. By forming, it is shaped into the desired suitable form. After extrusion from the die, compact heating (sintering) is performed to form a mass that is consistent with the original die configuration and properties associated with the metal used. The applied pressure affects the density and strength of the molded part, the higher the pressure, the higher the strength. A low density porous compact can be formed by pouring the powder into a die and then heating it without first applying pressure. The shape and dimensions of the die cavity should be as accurate as required by the finished product. However, if desired, the scope of the present invention extends to the use of any suitable metal or metal alloy powder and preferably iron or iron alloy powder.

  Referring to the drawings, FIG. 1 shows an essentially fully assembled rocker arm 20 having a rocker arm body 22, a hydraulic lash adjuster cartridge 24, a roller bearing 26 and a roller bearing mandrel 28. ing.

  Referring to FIG. 2, there are shown prefabricated parts (sections) 30, 32 of two sintered metals that form a rocker arm body 22 when sintered together. The rocker arm part (rocker arm section) 32 has grooves 34, 36 as a lubricant path which are combined by the two parts 30, 32, i.e. covered by surfaces 44, 46 during assembly. When formed, an oil passage (oil passage) is formed, which carries the lubricating oil provided by a rocker shaft (not shown) provided in the opening 38. The pre-formed lubricant paths 34, 36 can follow any desired path. The circuitous path consisting of the grooves 34 is easily realized by two rocker arm parts, which further allow the formation of openings 48, 50, 52 that reduce mass and rotational inertia. In addition, the structural beam element 42 can be formed to increase the rigidity of the rocker arm body shown in FIG.

  While the invention has been described in terms of a specific preferred embodiment, many variations and modifications will be apparent to those skilled in the art. Accordingly, the appended claims should be construed as broadly as possible with respect to the prior art to include all such variations and modifications.

A perspective view of a rocker arm assembly formed by joining two separate preformed parts planned according to the present invention attached to a rocker shaft (not shown) and a hydraulic lash adjuster cartridge housed therein FIG. FIG. 2 is a perspective view of two prefabricated mirror image parts of a rocker arm of the present invention. FIG. 3 is a perspective view of the assembled component shown in FIG. 2.

Claims (10)

  A method of manufacturing a sintered metal rocker arm from a prefabricated complementary mating part of metal powder, wherein at least one of said parts has an integrally formed lubricant passage and joins said parts Forming a rocker arm product having the integrally formed internal passage.   The method of claim 1, wherein the rocker arm is made by joining two complementary part halves.   The method of claim 2, wherein the lubricant passage is provided entirely within one or more of the prefabricated parts.   The method of claim 2, wherein the lubricant passage is formed when the complementary parts are joined together.   The method of claim 1, wherein the two complementary part halves are comprised of a powder metal alloy.   The method of claim 1, wherein the component is comprised of a powdered metal selected from iron and iron alloys.   The method of claim 1, wherein the parts are joined by metallurgical brazing.   A rocker arm manufactured by the method according to claim 1.   A rocker arm manufactured by the method according to claim 4.   A rocker arm manufactured by the method according to claim 6.

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