US3532080A - Device for driving poppet valves of an engine - Google Patents

Device for driving poppet valves of an engine Download PDF

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Publication number
US3532080A
US3532080A US725474A US3532080DA US3532080A US 3532080 A US3532080 A US 3532080A US 725474 A US725474 A US 725474A US 3532080D A US3532080D A US 3532080DA US 3532080 A US3532080 A US 3532080A
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US
United States
Prior art keywords
poppet valve
rocker arm
poppet
cam
driving
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
US725474A
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English (en)
Inventor
Yoshikazu Saruta
Kisaku Ohta
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.)
Nissan Motor Co Ltd
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Nissan Motor Co Ltd
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 Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Application granted granted Critical
Publication of US3532080A publication Critical patent/US3532080A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L1/185—Overhead end-pivot rocking arms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/14—Tappets; Push rods
    • F01L1/16—Silencing impact; Reducing wear

Definitions

  • This invention relates to a device for driving poppet valves of an engine, more particularly to a device for driving poppet valves of an overhead cam engine which is characterized by having a reduced operative noise.
  • poppet valves are driven by rocker arms, which rocker arms are in turn rotated around pivotal supporting means by cams located above a cylinder head.
  • cams located above a cylinder head.
  • suitable gaps in the driving mechanism of the poppet valves. Such gaps often cause the so-called tappet noise problem due to the frequent collision between the cams and the rocker arms, or between the rocker arms and the pop pet valves.
  • an object of the present invention is to minimize the noise level of the poppet valve driving mechanism due to collisions of various parts thereof, by providing a new poppet valve driving device which is much simpler than the hydraulic lifter, yet capable of materially reducing the noise level.
  • a bias spring is mounted on each rocker arm, in such manner that each rocker arm is always kept in slidable tight contact with the corresponding cam.
  • FIG. 1 is an elevation, partly in section, of a known poppet valve driving mechanism
  • FIG. 2 is a partial side view of the poppet valve driving mechanism, taken from the direction as shown by arrows Il-ll ofFlG. 1;
  • FIG. 3 is an elevation of a device for driving poppet valves, according to the present invention.
  • FIG. 4 is a plan view of the device of FIG. 3;
  • FIG. 5 is an elevation similar to FIG. 3, illustrating another embodiment of the present invention.
  • FIG. 6 is a plan view of the device of FIG. 5.
  • FIG. 7 is a sectional view of the device according to the present invention, shown in the state as mounted on an engine cylinder head.
  • a spring 6 is mounted on each rocker arm 2 in such manner that the rocker arm 2 is biased in a clockwise direction around a pivot 5. Accordingly, the poppet valve actuating portion 2a of each rocker arm is always kept in tight contact with the upper end of the poppet valve 3.
  • a gap A between the cam contact surface 2b of the rocker arm 2 and the cam 1 during each operative cycle of the engine.
  • Such gap'A is indispensable for absorbing the thermal expansion of the stem of the poppet valve 3, due to the high temperature rise at the engine cylinder by fuel combustion therein. In this case, the tappet noise is generated by the collision between the cam l and the rocker arms 2.
  • FIGS. 3 and 4 illustrate a device for driving poppet valves, according to the present invention.
  • the improvement achieved by the present invention is in the particular manner of mounting a spring 6 on a rocker arm 2. More particularly, the spring 6 is used so as to apply a bias force to the rocker arm 2 in a direction to keep the rocker arm 2 always in contact with a driving cam 2, while allowing a gap B between the poppet valve actuating end portion 2a of the rocker arm 2 and a cap 4 secured to the upper end of each poppet valve 3.
  • the rocker arm 2 is biased in a counterclockwise direction around a pivot head 5.
  • the spring has a pair of coiled portions bonded together by an intermediate portion 6a.
  • Both end portions 6b of the spring 6 are operatively held by a clip means 10 secured to a guide cylinder 9 supporting the pivot head 5.
  • the intermediate portion 6a of the spring 6 engages a shoulder 2c of the rocker arm 2, which shoulder 2c is formed at one end of an elongated portion of the rocker arm 2, which end of the elongated portion is located at a position over the pivot head 5.
  • the position of the shoulder 20 is opposite to the poppet valve actuating end portion 2a, with respect to the pivot head 5, as actually shown in FIG. 3 and FIG. 4. Due to the counterclockwise bias force of the spring 6, a cam contact surface 2b of the rocker arm 2 is always kept in operative contact with the driving cam 1 throughout the entire rotation thereof.
  • a gap B can be provided between the poppet valve actuating end 2a of the arm 2 and the cap 4 secured to the tip of the poppet valve 3, when the actuating portion 2a is brought to the proximity of its uppermost operative position thereof.
  • the thermal expansion of the poppet valve 3 can safely be absorbed by such gap B between the actuating end portion 2a of the rocker arm 2 and the cap 4 secured to the tip of the poppet valve 3.
  • the rocker arm 2 when the poppet valves are operated, the rocker arm 2 is struck only by individual poppet valves 3 at the gap B, while in the case of known poppet valve drive mechanism, the rocker arm 2 is struck at the gap A by the driving cam I integral with a journal shaft carrying a number of such cams. Due to the fact that the mass of an individual poppet valve 3 is far smaller than that of the driving cam means inclusive of the journal shaft having all the cams l integrally secured thereto, the energy of noise caused by striking of the rocker arms by individual poppet valves in the device of the present invention is greatly reduced, as compared with the corresponding noise energy of known driving mechanism caused by striking of the same rocker arms by much heavier driving cam means. The inventors confirmed such reduction in the noise level by carrying out a number of experiments.
  • FIGS. 5 and 6 show another embodiment of the poppet valve driving device, according to the present invention, including rocker arms rotatably carried by rocker shafts 11.
  • rocker arms 2 are rotatably mounted in two rows along a pair of rocker shafts l1, respectively.
  • a spring 6 is inserted between a stationary portion of the poppet valve driving device and each rocker arm 2, so as to apply a bias force to the rocker arm 2 in such direction that the cam contact surface 2b of each rocker arm 2 is always kept in slidable tight contact with the corresponding cam 1, respectively.
  • a gap B can be formed between the poppet valve actuating portion 2a of each rocker arm 2 and the upper end of the poppet valve 3, when the actuating portion 2a is brought into the proximity of its uppermost position. Accordingly, the level of the operating noise caused by the collision of the rocker arms 2 with individual poppet valves 3 is kept low.
  • P16. 7 shows a typical manner in which a poppet valve driving device, according to the present invention, is mounted on an engine cylinder head.
  • Each poppet valve 3 is slidably fitted in a valve guide 63 mounted on an engine cylinder head 61, so that the disk-shaped lower end valve portion of the poppet valve 3 can selectively engage the corresponding valve seat 62, which is integrally formed on the cylinder head 61.
  • a valve spring retainer 65 is secured to the upper end of each poppet valve 3, so as to retain a valve spring 64 inserted between the valve spring retainer 65 and a valve spring seat formed on the upper surface of the cylinder head 61.
  • a pivot head 5 is secured atop a threaded bolt, which is in turn screwed in a tapped boss formed on the upper surface of the cylinder head 61, so that each rocker arm 2 can be pivotally supported by the pivot head 5.
  • a cam shaft 12 to carry driving cams 1 is supported by a cam bracket 66 secured to the cylinder head 61 by a suitable means, such as bolts.
  • the poppet valve driving device including such rocker arms 2 and cams 1, as well as other parts associated therewith, are covered by a rocker cover 67, which is fastened to the cylinder head 61 with a gasket 68 inserted therebetween.
  • a device for driving poppet valves of an overhead cam engine comprising, in combination:
  • rocker arm having a poppet valve actuating portion at one end of said rocker arm, a middle portion, and an elongated end portion having a pivot head and guide cylinder on one side thereof, said rocker arm rotatably engaging said pivot head inside said elongated portion;
  • a cam means rotatably supported on a cam shaft and engageable with said cam contact surface to move said poppet valve actuating portion into either a valve opening or closing position;

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Valve Device For Special Equipments (AREA)
US725474A 1967-08-08 1968-04-30 Device for driving poppet valves of an engine Expired - Lifetime US3532080A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1967068014U JPS4619043Y1 (enrdf_load_stackoverflow) 1967-08-08 1967-08-08

Publications (1)

Publication Number Publication Date
US3532080A true US3532080A (en) 1970-10-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
US725474A Expired - Lifetime US3532080A (en) 1967-08-08 1968-04-30 Device for driving poppet valves of an engine

Country Status (6)

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US (1) US3532080A (enrdf_load_stackoverflow)
JP (1) JPS4619043Y1 (enrdf_load_stackoverflow)
BE (1) BE715392A (enrdf_load_stackoverflow)
FR (1) FR1580449A (enrdf_load_stackoverflow)
GB (1) GB1187545A (enrdf_load_stackoverflow)
NL (1) NL6806509A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3791355A (en) * 1972-02-24 1974-02-12 Johnson Products Inc Mechanical lash adjuster for overhead cam engines
US4658770A (en) * 1984-09-27 1987-04-21 Honda Giken Kogyo Kabushiki Kaisha Supporting structure for rocker arms for engine valves
US5738054A (en) * 1995-12-22 1998-04-14 Hyundai Motor Company Engine valve having adjustable lift
US8056518B1 (en) 2009-04-08 2011-11-15 Brunswick Corporation Valve lash adjustment nut
CN113482740A (zh) * 2021-07-29 2021-10-08 东风商用车有限公司 一种摇臂总成回位结构及可变气门升程机构

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6114407A (ja) * 1984-06-29 1986-01-22 Honda Motor Co Ltd 内燃機関の動弁装置
DE102016220394B3 (de) * 2016-10-18 2017-12-28 Schaeffler Technologies AG & Co. KG Zwischenhebel eines variablen Ventiltriebs

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3791355A (en) * 1972-02-24 1974-02-12 Johnson Products Inc Mechanical lash adjuster for overhead cam engines
US4658770A (en) * 1984-09-27 1987-04-21 Honda Giken Kogyo Kabushiki Kaisha Supporting structure for rocker arms for engine valves
US5738054A (en) * 1995-12-22 1998-04-14 Hyundai Motor Company Engine valve having adjustable lift
US8056518B1 (en) 2009-04-08 2011-11-15 Brunswick Corporation Valve lash adjustment nut
CN113482740A (zh) * 2021-07-29 2021-10-08 东风商用车有限公司 一种摇臂总成回位结构及可变气门升程机构
CN113482740B (zh) * 2021-07-29 2022-06-10 东风商用车有限公司 一种摇臂总成回位结构及可变气门升程机构

Also Published As

Publication number Publication date
NL6806509A (enrdf_load_stackoverflow) 1969-02-11
GB1187545A (en) 1970-04-08
BE715392A (enrdf_load_stackoverflow) 1968-10-16
DE1751448B2 (de) 1972-08-03
FR1580449A (enrdf_load_stackoverflow) 1969-09-05
DE1751448A1 (de) 1971-11-18
JPS4619043Y1 (enrdf_load_stackoverflow) 1971-07-02

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