Patent Application
20130199480
FIELD OF INVENTION
The present invention relates generally to internal combustion engines and more particularly to a method of manufacture of components of a switchable roller finger follower and to an intermediate assembly of the switchable roller finger follower.
Various methods of producing components for internal combustion engines are known. Some common methods of manufacturing components for internal combustion engines include forming the components individually by, for example, casting or forging. After forming, these components are typically then finished by machining before or after assembly. Alternatively, components for the internal combustion engine can be formed together and then separated by, for example, fracturing, sawing, or cutting. After the components are separated, any excess material can then be removed, and the surfaces connecting the components during forming are typically machined.
See, for example U.S. Pat. No. 7,250,070, which is directed to a method of forming a powder metal connecting rod that has a main body and a separable cap. The main body and cap are separated from each other by fracturing the main body and the cap. To fracture the main body and the cap, a tensile force is applied at a point of fracture between the main body and cap.
Also, see U.S. Patent Application No. 2008/0295789 for an example of a roller finger follower for valve deactivation.
In order to make performance improvements to an internal combustion engine, for example, to reduce fuel consumption, it is desirable to control valve opening events (e.g., cylinder deactivation). Also, for a valve train with a lever system cylinder deactivation, profile switching is accomplished by creating a lever that has lost motion capabilities.
The present invention is directed to a method of manufacturing spring pallets of a roller finger follower and a method of manufacturing an inner arm of a roller finger follower. The present invention is also directed to an intermediate assembly of the roller finger follower.
Spring pallets of a roller finger follower are typically manufactured with the inner arm of a roller finger follower. However, in the present invention the spring pallets are manufactured, for example by MIM or casting, separately from the inner arm. This allows for the inner arm to be manufactured as an individual sheet metal component and the spring pallets to be manufactured separately from the inner arm as a single spring pallet unit. Throughout the manufacturing process, the spring pallets are held together by a web of material. Prior to assembly, the spring pallet unit is separated into two spring pallets, which are mirror images of each other, and the spring pallets are assembled in the roller finger follower.
The manufacturing process of the present invention reduces the cost and time of manufacturing as the complexity of manufacturing the inner arm and the spring pallets is reduced. Moreover, the accuracy of the spring pallets is improved as the spring pallets are formed as mirror images of each other. Further, the manufacturing process allows for adjustment of the spring pallets in a roller finger follower assembly. Thus, by not fixing the spring pallets to the inner arm, the spring pallets can be placed in a more optimal position and orientation in the roller finger follower assembly.
Broadly, the present invention can be defined as a method for manufacturing spring pallets, of a switchable roller finger follower. The spring pallets comprise a first spring pallet, which has a first inner surface and a second spring pallet, which has a second inner surface. The method comprises the steps of forming the first spring pallet and the second spring pallet of the switchable roller finger follower as a single unit, forming a material web between the first spring pallet and the second spring pallet, and separating the first spring pallet from the second spring pallet.
The first spring pallet and the second spring pallet are manufactured by casting, forging or metal injection molding. There is an additional variation of this pallet, a universal fineblanked version, where there would be no mirror images.
The first spring pallet and the second spring pallet are mirror images of each other. Alternatively, the first spring pallet and the second spring pallet are manufactured by fineblanking manufacturing such that the first spring pallet and the second spring pallet are not mirror images of each other.
The spring pallets are separated by cracking, splitting, or cutting.
Also, the material web holding the first spring pallet and the second spring pallet together is a seam.
After being separated from each other, the spring pallets can be assembled with other components of the roller finger follower.
Additionally, the present invention broadly relates to an intermediate assembly of a roller finger follower. The intermediate assembly comprises a first spring pallet having a first inner surface, a second spring pallet having a second inner surface, and a material web extending between the first spring pallet and the second spring pallet. The material web adjoins the first spring pallet and the second spring pallet together.
The spring pallets are manufactured by casting, forging or metal injection molding.
The first spring pallet and the second spring pallet are mirror images of each other. Alternatively, the first spring pallet and the second spring pallet are not mirror images of each other.
The material web holding the first spring pallet and the second spring pallet together is a seam.
Further, the present invention broadly relates to a method for manufacturing an inner arm of a roller finger follower, which comprises the step of forming the inner arm as a sheet metal component. The inner arm can be formed, for example, by stamping.
The present invention will be further understood and appreciated by reading the following description in conjunction with the accompanying drawings, in which:
As shown in
By manufacturing the spring pallets 16, 18 as a single spring pallet unit, the cost of manufacturing and the volume of manufacturing the spring pallets 16, 18 and the inner arm 14 are significantly reduced. Also, the spring pallets 16, 18 are more accurately manufactured.
The present invention has been described with reference to a preferred embodiment. It should he understood that the scope of the present invention is defined by the claims and is not intended to be limited to the specific embodiment disclosed herein.
This application claims the priority of U.S. 61/594,789 filed Feb. 3, 2012, which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61594789 | Feb 2012 | US |
