TWO-PIECE FRICTION-WELDED PISTON
First Claim
1. A piston for use in an internal combustion engine, said piston comprising:
- an upper member, wherein said upper member is precision cast to net final dimensions, and said upper member includes a crown and a combustion surface extending radially inward from said crown, said upper member further including a first upper connecting surface and a second upper connecting surface, wherein said first and second upper connecting surfaces are concentrically oriented; and
a lower member, wherein said lower member is precision cast to net final dimensions, said lower member having a pair of opposing skirts, each skirt having a bore formed therethrough, and said lower member further including a first lower connecting surface and a second lower connecting surface, wherein said first and second lower connecting surfaces are concentrically oriented;
wherein said lower member is integrally connected to said upper member by friction welding such that said first upper connecting surface and said first lower connecting surface form a first welded joint therebetween and said second upper connecting surface and said second lower connecting surface form a second welded joint therebetween.
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Accused Products
Abstract
A two-piece piston is formed by friction welding an upper member to a lower member, wherein the upper and lower members are precision cast to net final dimensions such that no post-casting machining is required prior to the friction-welding process. The upper member includes a substantially flat crown and combustion surface extending radially inward from the crown. The lower member includes a pair of opposing skirts, each having a bore formed therethrough for receiving a connecting rod pin. The upper member and lower member each include at least two corresponding connecting surfaces that form a welded joint therebetween when the upper and lower members are friction welded together. The finished piston includes an integral cooling oil reservoir adjacent to the combustion surface.
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Citations
20 Claims
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1. A piston for use in an internal combustion engine, said piston comprising:
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an upper member, wherein said upper member is precision cast to net final dimensions, and said upper member includes a crown and a combustion surface extending radially inward from said crown, said upper member further including a first upper connecting surface and a second upper connecting surface, wherein said first and second upper connecting surfaces are concentrically oriented; and a lower member, wherein said lower member is precision cast to net final dimensions, said lower member having a pair of opposing skirts, each skirt having a bore formed therethrough, and said lower member further including a first lower connecting surface and a second lower connecting surface, wherein said first and second lower connecting surfaces are concentrically oriented; wherein said lower member is integrally connected to said upper member by friction welding such that said first upper connecting surface and said first lower connecting surface form a first welded joint therebetween and said second upper connecting surface and said second lower connecting surface form a second welded joint therebetween. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A piston for use in an internal combustion engine, said piston comprising:
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an upper member, said upper member being precision cast to net final dimensions, said upper member having a combustion surface and at least two concentrically positioned upper connecting surfaces spaced apart from said combustion surface; and a lower member, said lower member being precision cast to net final dimensions, said lower member having a pair of bores formed therethrough for receiving a connecting rod pin, and said lower member having at least two concentrically positioned lower connecting surfaces; wherein said lower member is attached to said upper member by way of friction welding such that each upper connecting surface of said upper member forms a welded joint with one of said lower connecting surfaces. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method of manufacturing a piston comprising:
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precision casting to net final dimensions an upper member, wherein said upper member includes a combustion surface and at least two upper connecting surfaces concentrically arranged and spaced apart from said combustion surface; precision casting to net final dimensions a lower member, wherein said lower member includes a pair of opposing skirts having a bore formed through each of said skirts, said lower member also including at least two lower connecting surfaces concentrically arranged; and friction welding said lower member to said upper member, wherein a welded joint is formed between each of said upper connecting surfaces of said upper member and a corresponding lower connecting surface of said lower member. - View Dependent Claims (19, 20)
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Specification