Tappet arrangement for engine valve train

• US 4,637,357 A
• Filed: 04/29/1985
• Issued: 01/20/1987
• Est. Priority Date: 04/29/1985
• Status: Expired due to Term

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Ohmi, Masatoshi
• Primary Examiner(s): Lazarus, Ira S.
• Application Number:
  US06/728,094
• Time in Patent Office: 631 Days
• Field of Search: 123/90.48, 123/90.27, 123/90.5
• US Class Current: 123/90.48
• CPC Class Codes: F01L 1/0532 the cams being directly in contact with the driven valve
• CPC Class Codes: F01L 1/143 for use with overhead camshafts
• CPC Class Codes: F01L 1/265 peculiar to machines or engines with three or more intake valves per cylinder
• CPC Class Codes: F01L 2307/00 Preventing the rotation of tappets
• CPC Class Codes: F02B 2275/18 DOHC [Double overhead camshaft]
• CPC Class Codes: F02F 1/4214 specially adapted for four or more valves per cylinder
• CPC Class Codes: F02F 2001/245 the valve stems being orientated at an angle with the cylinder axis

Abstract

A valve arrangement for an internal combustion engine that permits the use of a plurality of closely spaced valves. The valves are all directly actuated by means of thimble tappets that have non-cylindrical cross-sections so as to permit the tappet bodies to be positioned close to each other and yet afford a large area for their sliding support. The tappet bodies are also supported within the cylinder head assembly by means including a separate insert.

Claims

1. In a valve arrangement for an internal combustion engine comprising a cylinder head assembly, a plurality of poppet valves supported by said cylinder head assembly at one side thereof for reciprocation between opened and closed positions, said valves being juxtaposed to each other, a camshaft, and a plurality of slidably supported tappets supported by said cylinder head assembly and each interposed between said camshaft and a respective one of said valves, the improvement comprising at least one of said tappets being non-circular in cross-sections taken perpendicular to its line of reciprocation and having a short dimension extending in the direction of the adjacent valves and a long dimension extending in the perpendicular direction, the distance between said valves being less than said long dimension.

2. In a valve arrangement as set forth in claim 1 wherein the cylinder head assembly comprises a cylinder head that slidably supports the valves and a tappet body affixed to the cylinder head and supporting the tappets.

3. In a valve arrangement as set forth in claim 1 wherein there are three valves and the valves all serve the same function.

4. In a valve arrangement as set forth in claim 3 wherein the valves have non-parallel axes.

5. In a valve arrangement as set forth in claim 4 wherein the axes of the valves all intersect at a common point.

6. In a valve arrangement as set forth in claim 5 wherein the common point of intersection of the valve axes lies coincident with the axis of rotation of the camshaft.

7. In a valve arrangement as set forth in claim 1 wherein adjacent tappet bodies have flattened surfaces extending parallel to each other.

8. In a valve arrangement as set forth in claim 7 wherein the portions of the tappet bodies not adjacent to each other are semi-circular in cross-section.

9. In a valve arrangement as set forth in claim 8 wherein there are three valves and three tappet bodies, the central tappet body having parallel flattened sides connected by curves sections and the remaining tappet bodies have semi-cylindrical sides flattened adjacent to the central tappet body.

10. In a valve arrangement as set forth in claim 1 wherein the tappets have an insert interposed therebetween.

11. In a valve arrangement as set forth in claim 1 wherein the tappet bodies are slidably supported by a body of the cylinder head assembly formed with an opening therein and an insert received within the opening and engaging adjacent sides of the tappet bodies for their slidable support.

12. In a valve tappet arrangement for operating the valves of an internal combustion engine comprising an engine body defining a continuous opening, a pair of tappets disposed in said opening, having flat sides, and adapted to be supported for reciprocation, a single insert received within said opening and having respective surfaces engaged with said flat sides of said tappets for forming a bearing surface therefor.

13. In a valve tappet arrangement as set forth in claim 12 wherein the tappets have surfaces that are engaged with the engine body and other surfaces that are engaged with the insert.