Lubricating system for engine

• US 5,617,822 A
• Filed: 08/11/1995
• Issued: 04/08/1997
• Est. Priority Date: 07/26/1993
• Status: Expired due to Fees

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Masuda, Tatsuyuki
• Primary Examiner(s): Solis, Erick R.
• Application Number:
  US08/514,312
• Time in Patent Office: 606 Days
• Field of Search: 123/196 R, 123/196 W, 123/193.6, 184/6.5, 184/6.6, 92/158, 92/159, 92/160
• US Class Current: 123/196.00R
• CPC Class Codes: F01M 1/06 Lubricating systems characterised by the provision therein of crankshafts or connecting rods with lubricant passageways, e.g. bores crankshafts, connecting-rods, per se F16C
• CPC Class Codes: F01M 1/16 Controlling lubricant pressure or quantity rendering machines or engines inoperative or idling on lubricant pressure failure F01M1/22
• CPC Class Codes: F01M 11/02 Arrangements of lubricant conduits
• CPC Class Codes: F01M 9/00 Lubrication means having pertinent characteristics not provided for in, or of interest apart from, groups F01M1/00 - F01M7/00
• CPC Class Codes: F01M 9/06 Dip or splash lubrication
• CPC Class Codes: F01M 9/108 of auxiliaries
• CPC Class Codes: F02B 2075/025 two
• CPC Class Codes: F02B 2075/1812 three
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F05C 2201/021 Aluminium
• CPC Class Codes: F05C 2201/0448 Steel
• CPC Class Codes: F16N 2230/02 Microprocessor; Microcomputer
• CPC Class Codes: F16N 39/002 by deaeration degasification of liquids B01D19/00
• CPC Class Codes: F16N 7/26 Splash lubrication mist lubrication F16N7/32

Abstract

An improved lubrication system for a two-stroke engine having a lubrication path from an oil sump directly to an induction valve assembly for noise reduction. The oil sump is divided into two chambers with a restricted passage therebetween to ensure lubrication of transmission gears upon startup while reducing drag during operation. A cross-drilled lubrication passage through each crankshaft throw terminates in a second passage proximate a dead-end plug, the second passage being in communication with the piston rod bearing. Each piston skirt includes at least one axial groove in registration with an oil supply passage. Circumferential grooves distribute the oil around the piston skirt from the axial grooves. The pistons may include ceramic top layers for heat insulation to increase the compression ratio possible by raising the ring positions. The engine incorporates an air/oil mixture separator within a balancer shaft chamber and air from the chamber is directed to the intake system.

Claims

1. An arrangement for lubricating the crankshaft connecting rod journal of a reciprocating machine having a crankshaft journalled for rotation about a crankshaft axis and having a throw with a bearing portion eccentric relative to said axis for receiving the big end of a connecting rod, a first straight lubrication passage extending transversely and completely through said throw between an opening in the external surface of said throw and an inlet, a closure for closing said opening, and a second straight lubricating passage extending from said bearing portion to said first lubricating passage and intersecting said first lubricating passage adjacent said closure for minimizing the dead volume of said first lubricating passage between the point of intersection and said closure.

2. A lubricating arrangement as set forth in claim 1 further including means for introducing lubricant at a low pressure to the inlet.

3. A lubricating arrangement as set forth in claim 2 wherein the inlet is disposed in a side of the throw opposite the opening and the source of lubricant is lubricant which has been delivered to a main bearing of the crankshaft on the side where the inlet is disposed.

4. A lubricating arrangement as set forth in claim 3 wherein the inlet is disposed in alignment with the main bearing.

5. A lubricating arrangement as set forth in claim 4 wherein the connecting rod is journalled on the bearing portion by means of roller bearings.

6. A lubricating arrangement as set forth in claim 1 wherein the reciprocating machine comprises a two-stroke crankcase compression internal combustion engine.

7. A lubricating arrangement as set forth in claim 6 wherein the connecting rod is journalled on the bearing portion by means of roller bearings.

8. A lubricating arrangement as set forth in claim 7 wherein the first lubricating passage is disposed at an acute angle to the crankshaft rotational axis with the opening being disposed radially outwardly of the inlet so that centrifugal force pressurizes the lubricant delivered to the second lubricating passage.

9. A lubricating arrangement as set forth in claim 8 wherein the inlet is disposed in a side of the throw opposite the opening and the source of lubricant is lubricant which has been delivered to a main bearing of the crankshaft on the side where the inlet is disposed.

10. A lubricating arrangement as set forth in claim 9 wherein the inlet is disposed in alignment with the main bearing.

11. A lubricating arrangement as set forth in claim 6 further including a piston connected to the other end of the connecting rod by a piston pin and slidably supported within a cylinder bore.

12. A lubricating arrangement as set forth in claim 11 wherein the piston is provided with an axially extending groove terminating at its opposite ends and circumferentially extending grooves for distributing lubricant to the skirt of said piston.

13. A lubricating arrangement as set forth in claim 12 wherein there are grooves provided on opposite sides of the piston skirt in an area disposed substantially perpendicularly to the axis of the piston pin.

14. A lubricating arrangement as set forth in claim 12 further including an oil delivery hole extending through the cylinder block and intersecting its cylinder bore in a position swept by a skirt of the piston and in registry with the axially extending groove.

15. A lubricating arrangement as set forth in claim 14 wherein there is a groove arrangement and oil delivery passage on the sides of the piston disposed between the piston pin.

16. A lubricating arrangement for a reciprocating machine comprising a cylinder block defining a cylinder bore, a piston reciprocating in said cylinder bore, a lubricating passage extending through said cylinder block and intersecting said cylinder bore at a position swept by a skirt of said piston, and a lubricant distributing groove formed in said piston skirt comprising a first portion extending axially along said skirt and having at its ends circumferentially extending portions.

17. A lubricating arrangement as set forth in claim 16 wherein the circumferentially extending portions are inclined relative to the axis of the cylinder bore.

18. A lubricating arrangement as set forth in claim 17 wherein the inclined circumferentially extending portions extend from the respective ends of the first portion axially toward each other.

19. A lubricating arrangement as set forth in claim 18 wherein there are lubricant delivery grooves formed on diametrically opposite sides of the piston and each supplied with lubricant from a respective lubricating passage extending through the cylinder block and generally aligned with the first portions of the groove.

20. A lubricating arrangement as set forth in claim 16 wherein there are lubricant delivery grooves formed on diametrically opposite sides of the piston and each supplied with lubricant from a respective lubricating passage extending through the cylinder block and generally aligned with the first portions of the groove.