Hollow connecting rod

• US 5,140,869 A
• Filed: 06/24/1991
• Issued: 08/25/1992
• Est. Priority Date: 07/31/1989
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Mrdjenovich, Robert, Yeager, David A.
• Primary Examiner(s): LUONG, VINH
• Application Number:
  US07/720,276
• Time in Patent Office: 428 Days
• Field of Search: 74/579 R, 74/579 E, 74/579 F, 123/197 AB, 123/197 AC
• US Class Current: 74/579.00E
• CPC Class Codes: B22D 25/02 by its peculiarity of shape; of works of art cylinders, pistons B22D15/02
• CPC Class Codes: F16C 7/023 for piston engines, pumps or the like
• CPC Class Codes: Y10T 74/2142 Pitmans and connecting rods
• CPC Class Codes: Y10T 74/2162 Engine type

Abstract

A precision cast connecting rod which has an elongate tubular shank member defining a hollow section for producing desired stiffness to weight characteristics. Piston and crankpin connecting members are attached to opposite ends of the shank member. The connecting members are provided with passages which extend axially therewithin from the hollow section. Defined within the elongate tubular shank member is a radially extending central aperture.

Claims

1. A connecting rod for use in an engine including a piston wrist pin and a crankpin, the connecting rod comprising:

an elongate tubular shank member with two opposite ends;

a piston connecting member formed as one piece with one of the ends, the piston connecting member including a cylindrical surface adapted to cooperate with the piston wrist pin and defining a single first passage extending axially with respect to the shank member to the cylindrical surface;

a crankpin connecting member formed as one piece with the opposite end of the shank member, the crankpin connecting member including a generally semi-cylindrical surface having edges connected by an imaginary line disposed orthogonally to the shank member, the semi-cylindrical surface being adapted to cooperate rotatably with the crankpin, the crankpin connecting member defining a second passage extending axially with respect to the shank member to the semi-cylindrical surface; and

a pair of bolt holes extending through the crankpin connecting member for receiving bolts therethrough which attach the crankpin connecting member to the crankpin,

wherein the elongate tubular shank member, the piston connecting member, and the crankpin connecting member define therebetween an annular, hollow, section of generally constant diameter having an inner diameter which exceeds that of either passage, the section having a continuous outer convex curvilinear surface in the portion defined by the elongate tubular shank member for producing desired stiffness to weight characteristics in the connecting rod;

wherein the elongate tubular shank member is provided with a central aperture extending transversely therethrough proximate the crankpin connecting member.

2. The connecting rod of claim 1, wherein the elongate tubular shank member is provided with a wall having a minimum thickness of no more than about 3 millimeters.

3. The connecting rod of claim 1, in which the thin wall has a thickness of about 1 mm.

4. The connecting rod of claim 1, in which the tubular shank portion has an outside diameter of about 25 mm.

5. The connecting rod of claim 1 in which the tubular shank member is provided with a thin wall which has a thickness of about 0.5 mm.

6. The connecting rod of claim 1, in which the connecting rod is made from a material selected from the group consisting of a medium carbon alloy steel, a medium carbon steel, austempered iron, and ductile iron.

7. The connecting rod of claim 1, wherein the connecting rod is made of steel.

8. The connecting rod of claim 1, wherein at engine speeds up to about 10,000 RPM, the tensile loads withstood range up to about 6000 pound weight and the compressive loads withstood range up to about 10,000 pound weight without discernable degradation of the connecting rod.

9. The connecting rod of claim 1, wherein the tubular shank member has a thin wall of substantially the same thickness over its length.

10. The connecting rod of claim 1, in which the thin wall has a thickness of about 2 mm.

11. The connecting rod of claim 1, in which the tubular shank member has an outside diameter of about 15 mm to enable the elongate tubular shank member to withstand tensile and compressive loads while exhibiting favorable fatigue properties.