US3134306A - Piston construction - Google Patents

Piston construction Download PDF

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Publication number
US3134306A
US3134306A US138144A US13814461A US3134306A US 3134306 A US3134306 A US 3134306A US 138144 A US138144 A US 138144A US 13814461 A US13814461 A US 13814461A US 3134306 A US3134306 A US 3134306A
Authority
US
United States
Prior art keywords
piston
skirt
wrist pin
cylinder wall
straight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US138144A
Other languages
English (en)
Inventor
Robert C Schmidt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cummins Inc
Original Assignee
Cummins Engine Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cummins Engine Co Inc filed Critical Cummins Engine Co Inc
Priority to US138144A priority Critical patent/US3134306A/en
Priority to ES0280401A priority patent/ES280401A1/es
Priority to DK382762AA priority patent/DK105245C/da
Priority to SE9548/62A priority patent/SE302219B/xx
Priority to GB34149/62A priority patent/GB967767A/en
Priority to CH1086062A priority patent/CH399825A/de
Application granted granted Critical
Publication of US3134306A publication Critical patent/US3134306A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J1/00—Pistons; Trunk pistons; Plungers
    • F16J1/10—Connection to driving members
    • F16J1/14—Connection to driving members with connecting-rods, i.e. pivotal connections
    • F16J1/16—Connection to driving members with connecting-rods, i.e. pivotal connections with gudgeon-pin; Gudgeon-pins
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J1/00—Pistons; Trunk pistons; Plungers
    • F16J1/02—Bearing surfaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J1/00—Pistons; Trunk pistons; Plungers
    • F16J1/04—Resilient guiding parts, e.g. skirts, particularly for trunk pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • This invention relates to a piston, and more particularly to a piston for use in a rnulti-cyclinder internal combustion engine of the diesel type.
  • the general object of the invention is to provide an improved piston construction for use in a multi-cylinder internal combustion engine.
  • Another object is to provide an improved piston construction for use in an engine of the foregoing character, which permits a reduction in the over-all height and weight of the engine.
  • a further object is to provide an improved piston construction for use in an internal combustion engine of the diesel type which eliminates concentration of forces at the bottom of the skirt of the piston against the cylinder wall and consequently prevents scoring of the cylinder wall.
  • FIGURE 1 is a side elevational view of a piston and a portion of a connecting rod, the former embodying the features of the present invention.
  • FIG. 2 is a longitudinal sectional view taken along the line 22 of FIG. 1.
  • the piston construction of the present invention achieves the desired engine height and weight reduction in that it employs a novel short skirt construction and also avoids any concentration of forces.
  • the skirt portion of the piston is constructed so as to distribute the forces of the piston against the cylinder wall over a substantial area of contact rather than merely an edge contact. The unit stress on the cylinder wall is thus decreased, thereby reducing the tendency of the piston to score the cylinder wall.
  • the skirt of the present piston comprises upper and lower inwardly tapered end "ice portions and an intermediate straight portion, the angle of taper of the upper and lower portions being greater than the greatest angle of inclination of the piston in relation to the associated cylinder wall.
  • the skirt In addition to the tapered upper and lower end portions of the skirt, a novel relationship between the diameter of the wrist pin bore and the straight portion of the skirt is contemplated, the latter having an axial length such as to fall within the transverse projection of the wrist pin bore.
  • Such relationship provides a force system which reduces the tendency of the piston to tilt and contact the cylinder wall only at an edge. Instead, the piston engages the cylinder wall substantially throughout the area of the straight intermediate portion. Consequently, the forces are distributed over such area and result in a low unit stress, thereby avoiding chance of scoring the cylinder wall.
  • the skirt may be made only long enoughto provide support for the wrist pin.
  • FIGS. 1 and 2 a piston construction embodying the features of the present invention and indicated generally at 10 is illustrated.
  • the piston 10 in the present instance is shown operably disposed in a cylinder having a cylinder wall 11.
  • the piston 10 comprises a crown 12 and skirt 13.
  • the crown 12 is provided with one or more piston ring grooves, four such grooves 14 being shown.
  • the upper grooves are shown as shaped to receive rings 15 of the keystone type and the lower groove receives an oil ring 16.
  • the skirt 13 includes interior bosses 17 having a transverse bore 18 therethrough adapted to receive a wrist pin 19.
  • the wrist pin 19 serves to connect the piston 10 to the upper end, indicated at 22, of an associated connecting rod 23 connected to the crankshaft (not shown) of the engine.
  • the force due to combustion in the cylinder is exerted axially downwardly on the piston and is opposed by the reaction force of the crankshaft exerted through the connecting rod 23 on the wrist pin 19. Because of the angular position of the crankshaft during such power stroke, the connecting rod 23 moves to a position angularly relatedto the axis of the cylinder, as illustrated in FIG. 1. By such angular relationship, the force exerted on the wrist pin 19 has a transverse component tending to force the piston 10 against the cylinder wall 11, at one side thereof.
  • the present piston 10 utilizes a skirt 13 constructed so that it does not contact the cylinder wall at the lower edge of the skirt, but instead, contacts the wall only along a generally cylindrical or straight wall portion intermediate of its length.
  • the skirt 13 comprises a generally cylindrical or straight Wall portion 31 positioned intermediate the ends of the skirt and within the transverse projection of the wrist pin bore 18.
  • the axial center line, indicated at 32 :3 in FIG. 1, of the straight portion 31 in this instance is disposed somewhat below the center, indicated at 33 (FIGS. 1 and 2), of the wrist pin 19.
  • the skirt 13 of the present piston has a length only sufficient to provide enough material in the bosses 17 to support the wrist pin 19.
  • the lower and upper portions of the skirt, indicated at 34 and 36, respectively, below and above the straight portion 31, are relieved in order to provide clearance from the cylinder wall for these portions.
  • Such relieved portions 34 and 36 in this instance are tapered inwardly from the straight intermediate portion 31, the upper tapered portion 36 preferably being somewhat longer than the lower tapered portion 34.
  • the angles of taper indicated at A and B in FIG. 1, respectively, of the portions 34 and 36 are greater than the greatest angle of inclination to which the piston may be tilted in relation to the cylinder wall 11. This angle of inclination is quite small and consequently the angles A and B may also be small.
  • the total length of the skirt 13 is desirably as short as practical and preferably has a length only sufficient to provide enough material for the bosses 17 to support the wrist pin 19.
  • the lower end, indicated at 37, of the skirt 13' is disposed below the wrist pin bore 18 a sufficient distanceto provide enough metal in the bosses 17 and the upper end, indicated at 38, of the skirt 1.3 is located so as to space the wrist pin bore 18 below the lowermost piston ring groove 14 so that the groove is complete.
  • the novel skirt construction employed in the piston itl of the present invention results in a piston of reduced size and a connecting rod of shorter length, both of which permit reduction of the overall height and weight of the engine.
  • the present piston construction reduces any tendency of the piston to score the cylinder wall, both from the fact the forces are not concentrated at a line, and also because better lubrication is obtained.
  • the inwardly tapered portions 34 and 36 avoid a scraping action on the oil film on the cylinder wall, and the oil film is maintained on the cylinder wall.
  • the better lubrication permits use of a piston having less clearance from the cylinder wall with a consequent reduction in noise of operation.
  • a piston comprising a crown and skirt, said crown having at least one groove therearound adapted to receive a ring and said skirt having a bore therethrough adapted to receive a connecting rod wrist pin, said skirt having a straight intermediate portion and upper and lower end portions tapered inwardly from said intermediate portion, said straight portion being axially positioned within the transverse projection of said rwrist pin bore, the taper of said end portions being such that the side thrust from the connecting rod is confined to and distributed over said straight portion.
  • a piston according to claim 1 in which said straight portion has an axial length less than the diameter of said wrist pin bore.
  • a piston according to claim 1 in which the axial center of said straight portion is disposed below the center of said wrist pin bore.
  • a piston according to claim 1 in which the angle of taper of said upper and lower portions is greater than the greatest angle of inclination of said piston in relation to its associated cylinder wall.
  • a piston according to claim 1 in which said skirt has a length only sufficient to provide support for said wrist pin.
  • a piston comprising a crown and skirt, said crown having at least one groove therearound adapted to receive a ring and said skirt having a bore therethrough adapted to receive a wrist pin, said skirt having a straight intermediate portion and end portions tapered inwardly from said intermediate portion, said skirt also having wrist pin bosses formed therein, the bottom edge of the lower portion of said skirt being located substantially at the lowermost portion of said bosses.
  • a piston according to claim 8 in which the upper end of said skirt has a length only sufiicient to provide support for said wrist pin and to space said wrist pin bore below said groove.
  • a piston according to claim 9 in which the angle of taper of said upper and lower end portions is greater than the greatest angle of inclination of said piston in relation to its associated cylinder wall.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
US138144A 1961-09-14 1961-09-14 Piston construction Expired - Lifetime US3134306A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US138144A US3134306A (en) 1961-09-14 1961-09-14 Piston construction
ES0280401A ES280401A1 (es) 1961-09-14 1962-08-30 Mejoras introducidas en la fabricaciën de pistones
DK382762AA DK105245C (da) 1961-09-14 1962-08-31 Motorstempel med tilspidsende endedele.
SE9548/62A SE302219B (da) 1961-09-14 1962-09-04
GB34149/62A GB967767A (en) 1961-09-14 1962-09-06 A piston
CH1086062A CH399825A (de) 1961-09-14 1962-09-12 Kolben

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US138144A US3134306A (en) 1961-09-14 1961-09-14 Piston construction

Publications (1)

Publication Number Publication Date
US3134306A true US3134306A (en) 1964-05-26

Family

ID=22480630

Family Applications (1)

Application Number Title Priority Date Filing Date
US138144A Expired - Lifetime US3134306A (en) 1961-09-14 1961-09-14 Piston construction

Country Status (6)

Country Link
US (1) US3134306A (da)
CH (1) CH399825A (da)
DK (1) DK105245C (da)
ES (1) ES280401A1 (da)
GB (1) GB967767A (da)
SE (1) SE302219B (da)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3463057A (en) * 1967-03-23 1969-08-26 Int Harvester Co Arrangement of cylinder and piston in engine
US20110011079A1 (en) * 2007-04-23 2011-01-20 New Power Concepts Llc Stirling cycle machine
US11448158B2 (en) 2007-04-23 2022-09-20 New Power Concepts Llc Stirling cycle machine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH493739A (de) * 1968-07-08 1970-07-15 Sulzer Ag Arbeitskolben einer Kolbenbrennkraftmaschine
ZA825602B (en) * 1981-08-11 1984-03-28 Ae Plc Pistons
LU84311A1 (fr) * 1981-08-11 1984-03-23 Ae Plc Pistons

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1561379A (en) * 1924-08-09 1925-11-10 Wilfred G Unger Piston and piston ring
GB582465A (en) * 1944-05-16 1946-11-18 John Ernest Wainwright Improvements in pistons and reciprocating valves
US2483674A (en) * 1945-12-15 1949-10-04 Caterpillar Tractor Co Piston

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1561379A (en) * 1924-08-09 1925-11-10 Wilfred G Unger Piston and piston ring
GB582465A (en) * 1944-05-16 1946-11-18 John Ernest Wainwright Improvements in pistons and reciprocating valves
US2483674A (en) * 1945-12-15 1949-10-04 Caterpillar Tractor Co Piston

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3463057A (en) * 1967-03-23 1969-08-26 Int Harvester Co Arrangement of cylinder and piston in engine
US20110011079A1 (en) * 2007-04-23 2011-01-20 New Power Concepts Llc Stirling cycle machine
US8763391B2 (en) * 2007-04-23 2014-07-01 Deka Products Limited Partnership Stirling cycle machine
US20150047336A1 (en) * 2007-04-23 2015-02-19 New Power Concepts Llc Stirling Cycle Machine
US9797340B2 (en) * 2007-04-23 2017-10-24 New Power Concepts Llc Stirling cycle machine
US11448158B2 (en) 2007-04-23 2022-09-20 New Power Concepts Llc Stirling cycle machine
US12078123B2 (en) 2007-04-23 2024-09-03 Deka Products Limited Partnership Stirling cycle machine
US12104552B2 (en) 2007-04-23 2024-10-01 Deka Products Limited Partnership Stirling cycle machine

Also Published As

Publication number Publication date
CH399825A (de) 1965-09-30
GB967767A (en) 1964-08-26
ES280401A1 (es) 1962-12-16
SE302219B (da) 1968-07-08
DK105245C (da) 1966-09-05

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