CA1112910A - Drive mechanism for piston engines - Google Patents

Drive mechanism for piston engines

Info

Publication number
CA1112910A
CA1112910A CA346,850A CA346850A CA1112910A CA 1112910 A CA1112910 A CA 1112910A CA 346850 A CA346850 A CA 346850A CA 1112910 A CA1112910 A CA 1112910A
Authority
CA
Canada
Prior art keywords
gear
secured
drive
drive mechanism
gears
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
Application number
CA346,850A
Other languages
French (fr)
Inventor
Arnold J. Schwemin
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.)
Energy Dynamics Inc
Original Assignee
Energy Dynamics 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 Energy Dynamics Inc filed Critical Energy Dynamics Inc
Priority to CA346,850A priority Critical patent/CA1112910A/en
Priority to SE8001696A priority patent/SE8001696L/en
Priority to GB8008225A priority patent/GB2071260B/en
Priority to FR8005780A priority patent/FR2478195B1/en
Priority to DE19803010933 priority patent/DE3010933A1/en
Application granted granted Critical
Publication of CA1112910A publication Critical patent/CA1112910A/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01BMACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B9/00Reciprocating-piston machines or engines characterised by connections between pistons and main shafts and not specific to preceding groups
    • F01B9/04Reciprocating-piston machines or engines characterised by connections between pistons and main shafts and not specific to preceding groups with rotary main shaft other than crankshaft
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00Other engines
    • F02B75/06Engines with means for equalising torque
    • F02B75/065Engines with means for equalising torque with double connecting rods or crankshafts
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02GHOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
    • F02G1/00Hot gas positive-displacement engine plants
    • F02G1/04Hot gas positive-displacement engine plants of closed-cycle type
    • F02G1/043Hot gas positive-displacement engine plants of closed-cycle type the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H21/00Gearings comprising primarily only links or levers, with or without slides
    • F16H21/10Gearings comprising primarily only links or levers, with or without slides all movement being in, or parallel to, a single plane
    • F16H21/16Gearings comprising primarily only links or levers, with or without slides all movement being in, or parallel to, a single plane for interconverting rotary motion and reciprocating motion
    • F16H21/18Crank gearings; Eccentric gearings
    • F16H21/22Crank gearings; Eccentric gearings with one connecting-rod and one guided slide to each crank or eccentric
    • F16H21/30Crank gearings; Eccentric gearings with one connecting-rod and one guided slide to each crank or eccentric with members having rolling contact
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02GHOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
    • F02G2270/00Constructional features
    • F02G2270/42Displacer drives
    • F02G2270/425Displacer drives the displacer being driven by a four-bar mechanism, e.g. a rhombic mechanism

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transmission Devices (AREA)
  • Hydraulic Motors (AREA)

Abstract

Abstract of the Disclosure A drive mechanism for linking the pistons of a heat engine to a rotating drive shaft includes a housing through which the drive shaft extends in rotatable fashion. Secured to the drive shaft within the housing is a main bevelled gear. A plurality of bevelled drive gears engage the main gear, each drive gear being secured to a gear shaft which extends through the exterior of the housing. Secured to the exterior end of each gear shaft is a gear wheel, which meshes with a similar, free-wheeling gear wheel. A pair of eccentric arms are secured to each pair of meshing gear wheels, their distal ends being secured to a block. A piston rod is also secured to the block, so that the reciprocal motion of the piston rod may be transferred through the eccentric arms and the gear wheels to the drive gear and the main gear.

Description

In the field of heat engines, the piston engine has gained wide acceptance in the past century, primarily because of its reliability, control-lability, and its desirable power output characteristics. Recently, interest has increased in external combustion piston engines, such as the Stirling cycle and Rankine cycle engines.
Typically, a piston is linked to a mechanism for transforming the reciprocating motion of the piston to smooth rotary motion. Often, this mechanism includes a piston rod extending from the piston to a crank on the crankshaft. The eccentric disposition with respect to the shaft enables it to accommodate the translational motion of the piston rod, and transform the periodic, reciprocating force provided by the piston into smooth rotational motion. Other mechanisms include swash plate and wobble plate devices.
It is well known in the art that the eccentric disposition of the crank of a crankshaft and the motion of a swash plate also causes the piston rod to undergo lateral motion as well as translational motion. This lateral motion is generally accommodated by a wrist pin which links the piston to the respective end of the piston rod. This mechanical system, however, does not entirely alleviate the side thrust which is attendant with the lateral motion of the piston rod. This side thrust, exerted on the piston through the wrist pin, causes uneven wearing of the piston rings, or similar seal, and a deg-radation of the seal disposed between the piston rod and the end of the cylinder. The side thrust also contributes to the wear of the main bearings which support the crank shaft.
Although the wear which is associated with the side thrust of the piston rod has been minimized by superior design, balancing, and machining, it still remains a significant factor in limiting the life span of an engine.
The end of this lifespan is often determined by the time at which the engine must be re6uilt, including new piston rings, seals bearings, and the like.

According to the present invention 1:here is provided a drive mechanism for linking the reciprocating pistons of an engine to a rotating shaft, comprising a main gear disposed on saicl rotating shaft; at least one drive gear engaging said main gear; a piston rod extending from each of said pistons; a plurality of paired eccentric armsJ each pair of which is joined at one end thereof to one of said piston rods; a plurality of gear wheels, each joined to one of said drive gears in common rotation therewith; a plurality of idler gears, each meshing with one of said gear wheels in paired relationship; and wherein each of the other ends of said each pair of eccen-tric arms is joined to one of a pair of said idler gears and said gear wheels.
The present invention generally comprises a drive mechanism forlinking the pistons of a heat engine to the rotary output shaft thereof, and for converting the reciprocating motion of the pistons to the rotary power output of the output shaft. A significant aspect of the present invention is that it virtually eliminates the side thrust exerted on the piston rod and on the piston, and thereby eliminates a major cause of wear and prolongs the life of the engine. It also allows a simple slide seal on the piston rod to seal hydrogen or helium gas below the piston, as used in Stirling cycle engines.
A preferred embodiment of the invention includes a housing having an output shaft extending therethrough, the shaft being supported by bearings journalled in the housing. A main bevel gear is secured to the output shaft within the housing, and it engages a plurality of drive gears also disposed within the housing. Each of the drive gears is secured to the proximal end of a gear shaft, the gear shaft extending through the wall of the housing to the exterior thereof and being supported by bearings journalled therein.
Secured to the distal end of each gear shaft is a gear wheel, which meshes with an idler gear disposed directly adjacent thereto. Extending ec-centrically from the gear wheel and the idler gear are a pair of eccentric r 2 r Li;) arms, which are secured at their other ends to a connecting block.
Also secured to the connecting block is the distal end of the piston rod, the proximal end being secured to the piston itself. As the piston re-ciprocates the reciprocal motion is transferred through the piston rod to the connecting block. The block drives the eccentric arms which cause the gear wheel and idler gear to rotate. This rotational motion is transferred through the gear shaft to the drive gear and thence to the main gear. In this way the output shaft of the drive mechanism is driven in continuous rotational motion.
The piston rod undergoes direct translational motion along its axis, due to the equal arm effect of the eccentric linking members. Thus there is no side thrust exerted on the piston rod, or on the piston itself; and the wear of the piston, the piston rod, the piston rings or seals, and the cylinder walls is greatly reduced.
In the accompanying drawings:
Figure 1 is a plan view of a drive mechanism embodying the present invention, shown in conjunction with a piston engine;
Figure 2 is an end view of the drive mechanism;
Figure 3 is a detailed, cross-sectional view of a portion of the drive mechanism;
2Q Figure 4 is a detailed plan view of the dual eccentric arm feature of the present invention, shown in a disposition commensurate with the mid-point of the piston excursion;
Figure 5 is a detailed plan view as in Figure 4, shown in a position commensurate with the top dead center position of the piston excursion;
Figure 6 is a detailed plan view as in Figures 4 and 5, shown in a disposition commensurate with the midpoint of the piston excursion; and Figure 7 is a schematic depiction of various piston positions within its respective cylinder.

The present invention generally comprises a drive mechanism, for use in conjunction with a piston engine, which links the pistons of the engine to the rotary output shaft thereof. The drive mechanism converts the recip-rocal motion of the pistons to smooth rotary motion of the output shaft, and it exhibits the significant advantage of imparting no side thrust to the pis-tons or connecting rods of the engine. In describing the preferred embodiment, reference will be made to a four-cylinder heat engine, and the preferred em-bodiment will be described in relation thereto. However, the invention is not limited by the number of cylinders in the engine, nor by the type of heat en-gine with which it is used.
As shown in Figures 1 and 2, the drive mechanism embodying the present invention includes a generally rectangular housing 11 which is secured to one side of a base plate 12. Joined to the other side of the base plate are a plurality of cylinders 13. Within each cylinder 13 there is disposed a piston 14 which is driven by expanding gasses provided by external combustion of a fuel.
As shown in Figure 3, within the housing 11 there is a cavity 16.
Disposed in this cavity and extending out of the upper end of the housing 11 is a rotary output shaft 17. The shaft 17 is supported by at least a pair of bearings 18 and 19 to provide free rotation of the shaft 17. Supported on the shaft 17 within the cavity 16 is a main gear 21, of the bevel type, as shown in Figure 3.
Extending into each side 22 of the rectangular housing 11 is a gear shaft 24, which is supported by needle bearings journalled in the side 22.
Secured to the inner end of each gear shaft 24 is a bevelled drive gear 26 which meshes with the main gear 21. The gears 21 and 26 all have an even num-ber of teeth. Thus all of the gears 26 and the shafts 24 rotate in synchron-ism with the gear 21 and the output shaft 17. The gears 21 and 26 may alter-;23 ~ ~

natively comprise spur gears, worm gears, or helical gears having any de-sired ratio of increase or decrease.
Extending outwardly from each of the sides 22 is a support arm 23.
An idler gear shaft 27 is rotatably supported by the arm 23, and an idler gear 28 secured to the outer end of the shaft 27. Secured to the outer end of each of the shafts 24 is a gear wheel 29, which is disposed to mesh with the gear 28. The diameter and number of teeth of the gears 29 and 28 are identical.
Secured to each of the gear wheels 29 and idler gears 28 is an ec-centric arm 31, all of the arms 31 being identical in length. Each of the arms 31 is secured to its respective idler gear or gear wheel by means of a stub shaft extending therefrom, and a needle bearing which provides for free rotation of the eccentric arm about the stub shaft. For each gear wheel and idler gear pair, there is provided one connecting block 32, to which the ec-centric arms 31 of the respective gear pair are secured. The connecting block 32 is also provided with a pair of stub shafts and needle bearing assemblies -so that the eccentric arms 31 may freely rotate with respect to the connecting block.
Also secured to each connecting block 32 is a piston rod 33 which extends from the connecting block to the piston 14 disposed in the cylinder 13 which is axially aligned with the respective connecting block. A suitably aligned port 15 in the plate 12 is provided for each rod 33 so that it may pass therethrough in freely rotation fashion. Each port 15 is provided with a sleeve or gland seal 25, such as those fabricated from lubricant impregnated plastic material.
It may be appreciated that the differential in pressure exerted on the opposed sides of the piston 14 causes it to reciprocate in the cylinder 13, as is well known in the art. The piston drives the associated piston rod 33 in reciprocal motion, translating along the axis of the piston rod. Like-~, - 5 -~S 23f~~~

wise, the connecting block 32 is driven reciprocally by the piston rod 33.
It should be noted that each pair of eccentric arms 31 are secured to their respective gear wheel and idler gear pair in exactly opposed relationship.
That is, the shafts which connect the eccentric arms to their respective gears define a line which is always parallel to the line defined by the axes of rotation of the gear wheel and idler gear pair. Furthermore, each piston rod 33 extends along an axis which is midway between the rotational axes of its associated gear wheel and idler gear pair. Due to these symmetrical re-lationships, each connecting block 32 is maintained by its eccentric arms 31 on the axis which falls midway between its respective gear pair 29 and 28.
Thus as the connecting block 32 and the piston rod 33 translate reciprocally and drive the gear pair 29 and 28 through the eccentric arms 31, they are prevented from undergoing any lateral, non-axial motion due to the action of the equally opposed eccentric arms.
As the piston 14 translates from top dead center through inter-mediate positions to the bottom dead center, as shown in Figure 7, the gears 29 and 28 are driven by the eccentric arms 31 through commensurate rotational angles, as shown in Figures 4, 5 and 6. That is, the block 32 drives the eccentric arms 31 which cause the gear wheel 29 and the idler gear 28 to rotate. This ~otational motion is transferred through the gear shaft 27 to the drive gear 26 and thence to the main gear 21. In this way the output shaft 17 of the drive mechanism is driven in continuous rotational motion.
In all cases, however, the connecting block 32 and the piston rod 33 are maintained by the eccentric arms 31 on the same axis, so that the piston rods and connecting blocks undergo axial translation only. Thus, there is no side thrust imparted to the connecting block or piston rod, or piston rod seal 25, and therefore no side thrust is imparted by the piston rod 33 to the piston 14 itself.

:

The direction of rotation of output shaft 7 may be reversed by exchanging the phase angle of any two opposed gear~s 26.
Thus the mechanism of the present invention not only converts the reciprocal motion of the pistons 1~l to rotational motion of the output shaft 17, it also alleviates any side thrust which might be exerted on the pistons and piston rod seals by the piston rods. In this way, a major cause of wear of the pistons, cylinder walls, and intermediate seals, is eliminated. Thus, the efficiency of the engine is increased, since compression within the cylinder is maintained over the operating life of the engine. Furthermore, the operating life of the engine is greatly extended, since the elimination of side thrust on the piston greatly reduces the wear thereof.
It should also be noted that each gear assembly 29 and 28 is dyna-mically balanced to alleviate any undue vibrational effects which might occur when the drive mechanism is operating at speed. Furthermore, each pair of eccentric arms 31 are also dynamically balanced, and close machine tolerances are observed in all phases of the construction of the present invention.
A significant advantage of the present invention is that the marked reduction in side thrust on the pistons and rods also reduces the lubrication requirements of the engine. Thus the gears and seals of the device may be permanently lubricated with suitable coatings or impregnations, and the typical oil pump, splash, or spray lube system eliminated. This is a significant advance for Stirling cycle engines in which the heat exchangers are often clogged and contaminated by lubricating oil leaking past the seals.
It should be emphasized that the piston engine forms no part of the present invention. Furthermore, the drive mechanism of the present invention may be employed with any form of reciprocating piston engine, including external combustion engines, steam engines, and the like.

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A drive mechanism for linking the reciprocating pistons of an engine to a rotating shaft, comprising a main gear disposed on said rotating shaft;
at least one drive gear engaging said main gear; a piston rod extending from each of said pistons; a plurality of paired eccentric arms, each pair of which is joined at one end thereof to one of said piston rods; a plurality of gear wheels, each joined to one of said drive gears in common rotation therewith;
a plurality of idler gears, each meshing with one of said gear wheels in paired relationship; and wherein each of the other ends of said each pair of eccentric arms is joined to one of a pair of said idler gears and said gear wheels.
2. The drive mechanism of claim 1, wherein all of said plurality of said eccentric arms are equal in length and are secured to said idler gear wheel pairs in symmetrically opposed relationship.
3. The drive mechanism of claim 1, wherein said gear wheels and said idler gears are all equal in diameter and number of teeth.
4. The drive mechanism of claim 1, further including a connecting block secured to said one end of said eccentric arms and said one end of said piston rods.
5. The drive mechanism of claim 1, wherein said main gear and said drive gears comprise bevel gears, and further including a plurality of gear shafts, each secured to one of said drive gears.
6. The drive mechanism of claim 5, wherein each of said gear wheels is secured to one of said gear shafts.
7. The drive mechanism of claim 1, wherein said drive gears are ar-ranged in opposed, paired relationship, and wherein the phase angles of any of said pairs of drive gears are selectively interchangeable to reverse the direction of rotation of said rotating shaft.
CA346,850A 1980-03-03 1980-03-03 Drive mechanism for piston engines Expired CA1112910A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA346,850A CA1112910A (en) 1980-03-03 1980-03-03 Drive mechanism for piston engines
SE8001696A SE8001696L (en) 1980-03-03 1980-03-05 POWER ENGINE DRIVE MECHANISM
GB8008225A GB2071260B (en) 1980-03-03 1980-03-11 Drive mechanism for a piston engine
FR8005780A FR2478195B1 (en) 1980-03-03 1980-03-14 TRANSMISSION MECHANISM OF THE PISTON MOTION OF AN ENGINE
DE19803010933 DE3010933A1 (en) 1980-03-03 1980-03-21 Drive arrangement for piston engines

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
CA346,850A CA1112910A (en) 1980-03-03 1980-03-03 Drive mechanism for piston engines
SE8001696A SE8001696L (en) 1980-03-03 1980-03-05 POWER ENGINE DRIVE MECHANISM
GB8008225A GB2071260B (en) 1980-03-03 1980-03-11 Drive mechanism for a piston engine
FR8005780A FR2478195B1 (en) 1980-03-03 1980-03-14 TRANSMISSION MECHANISM OF THE PISTON MOTION OF AN ENGINE
DE19803010933 DE3010933A1 (en) 1980-03-03 1980-03-21 Drive arrangement for piston engines

Publications (1)

Publication Number Publication Date
CA1112910A true CA1112910A (en) 1981-11-24

Family

ID=41360110

Family Applications (1)

Application Number Title Priority Date Filing Date
CA346,850A Expired CA1112910A (en) 1980-03-03 1980-03-03 Drive mechanism for piston engines

Country Status (5)

Country Link
CA (1) CA1112910A (en)
DE (1) DE3010933A1 (en)
FR (1) FR2478195B1 (en)
GB (1) GB2071260B (en)
SE (1) SE8001696L (en)

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR745820A (en) * 1933-05-17
FR773098A (en) * 1933-05-10 1934-11-10 New type of internal combustion engine
US2417910A (en) * 1942-06-20 1947-03-25 Robert D Bruegger Internal-combustion engine
US4207774A (en) * 1977-11-04 1980-06-17 Energy Dynamics, Inc. Drive mechanism for piston engines

Also Published As

Publication number Publication date
GB2071260B (en) 1983-10-05
FR2478195A1 (en) 1981-09-18
GB2071260A (en) 1981-09-16
DE3010933A1 (en) 1981-10-01
FR2478195B1 (en) 1987-07-24
SE8001696L (en) 1981-09-06

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