CA1039516A - Hot-gas reciprocating engine - Google Patents
Hot-gas reciprocating engineInfo
- Publication number
- CA1039516A CA1039516A CA238,907A CA238907A CA1039516A CA 1039516 A CA1039516 A CA 1039516A CA 238907 A CA238907 A CA 238907A CA 1039516 A CA1039516 A CA 1039516A
- Authority
- CA
- Canada
- Prior art keywords
- swashplate
- rods
- spring
- tilting
- shaft
- 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
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G1/00—Hot gas positive-displacement engine plants
- F02G1/04—Hot gas positive-displacement engine plants of closed-cycle type
- F02G1/043—Hot 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
- F02G1/044—Hot 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 having at least two working members, e.g. pistons, delivering power output
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G1/00—Hot gas positive-displacement engine plants
- F02G1/04—Hot gas positive-displacement engine plants of closed-cycle type
- F02G1/043—Hot 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
- F02G1/045—Controlling
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G2244/00—Machines having two pistons
- F02G2244/50—Double acting piston machines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G2270/00—Constructional features
- F02G2270/20—Plural piston swash plates
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
- Transmission Devices (AREA)
- Reciprocating Pumps (AREA)
Abstract
ABSTRACT:
A hot-gas reciprocating engine having at least three reciprocable piston-like members each having a driving rod which co-operates, via a sliding member, with a plate which is provided on a rotatably journal-led shaft in such manner that said plate cannot perform a rotation relative to the shaft but can tilt about a tilting shaft extending transversely to the centre line of the shaft, means being furthermore present to tilt the plate and the plate being also coupled to a spring mechanism which exerts a torque on the plate, said tor-que being directed opposite to, being as large as, and varying in the same manner with the angle which the plate encloses with the shaft as the torque exerted on the plate by the pistons.
A hot-gas reciprocating engine having at least three reciprocable piston-like members each having a driving rod which co-operates, via a sliding member, with a plate which is provided on a rotatably journal-led shaft in such manner that said plate cannot perform a rotation relative to the shaft but can tilt about a tilting shaft extending transversely to the centre line of the shaft, means being furthermore present to tilt the plate and the plate being also coupled to a spring mechanism which exerts a torque on the plate, said tor-que being directed opposite to, being as large as, and varying in the same manner with the angle which the plate encloses with the shaft as the torque exerted on the plate by the pistons.
Description
~ )39516 The invention relates to a spring compensation mechanism for a swash-plate drive. A known hot-gas reciprocating engine has at least three recipro-cable piston-like members each having a driving rod which, via a sliding mem- ~`~
` ber, co-operates with a plate. The plate is provlded on a rotatably journalled shaft in such a manner that the splate connot perform a rotation relative to the shaft but can tilt about a tilting shaft extending transversely to the centre line of the shaft. Means are also provided to tilt the plate.
Hot-gas reciprocating engines of the above-mentioned type are known ; from the United States Patent Specification 3,511,102. -~
In said known hot-gas reciprocating engine, a variation in the stroke of the pistons co-operating with said plate is effected by tilting the plate about the tilting shaft. This results in a variation of the supplied power in engines and in a variation of the cooling capacity in refrigerators.
During operation of a hot-gas reciprocating engine, a torque always acts on the plate which tries to rotate the plate to the position at right angles to the shaft. The torque is directly proportional to the angle which the plate encloses with the plane perpendicular to the shaft and is substan-tially not dependent on the number of revolutions.
In controlling the power of these machines, the torque co-operates or counteracts, dependent on the increase or decrease of the power.
In order to increase the power tha plate should be moved against the torque. In order to be able to do this rapidly, much power is required which, in certain circumstances, is not available. On the contrary, when .;
decreasing the power, with co-operating torque, there is excessive power.
The excessive power should be stored temporaril~ so that it can be used afterwards.
; . ~
!.
~ 2-.
~3~ 6 I~ is an object of the invention to provide a spring compensation mechanism for a hot-gas reciprocating engille which can be controlled rapidly and with little power.
Accordingly, the apparatus of the invention is a spring compensa-tion mechanism for a swashplate drive, said drive including a drive shaft mounted for rotation about its center line, a tilting shaft extending trans-versely to the center line of the drive shaft, a swashplate tiltably mounted about said tilting shaft and coupled to said drive shaft for rotation there-with, a plurality of driving rods mounted for reciprocating movement r01ative to said drive shaft, said drive rods being coupled to said swashplate such that, the swashplate being tilted at an oblique angle with respect to the drive shaft center line, driving force exerted by said rods against said swashplate imparts rotational torque to said swashplate for rotating said drive shaft, said force also tending to tilt said swashplate toward a position perpendicular to said center line, and means for tilting said swashplate about said tilting shaft, wherein said mechanism comprises a pair of compensating rods, means for coupling one end of each of said rods to the swash plate and for guiding said one ends for movement in a first direction in response to tilting of said swash plate, the other ends of said rods being guided for movement in a direction transverse to said first direction and a spring coupled to said other ends and arranged to be resiliently stressed by movement of said rod other ends in response to tilting of the swashplate, ~;
the spring constant and orientation of said spring being such ~hat stressing -: of the spring produces a change in force proportional to the force change caused by the tendency of said driving rods to tilt said swashplate toward said perpendicular position.
.~
~1 .~
.
1~3~35~6 So in this manner, with downward controlJ a quantity of energy will be stored in the spring mechanism, which energy can be used when increasing the power to vary the position of the plate. As a result of this the control can be carried out rapidl~ and with little power. The spring mechanism may comprise both mechanic and gas spring constructions.
; The rod of the spring mechanism in this construction is in equilib-rium of forces ~balanced) in any position. When the position varies, trans- ;
port of energy will take place from the spring which acts on one end of the rod to the spring co-operating with the other end of the rod. The spring which co-operates with one end of the rod has as it were a negative spring characteristic. ;
In a favourable embodiment the spring mechanism comprises at least one pair of identical rods which are pivotall~ coupled together and in which the free ends of the two rods are straight-guided in the same direction, the pivot being coupled to the plate and the two free ends being each coupled to a spring, or conversely, the spring constant of the two springs together being ^ ' '.
,.
;
s-~6 substantially equal to the spring constant of the gas forces acting on the plate via the piston-like members.
In a further embodiment the spring mechanism comprises at least four identical rods which are pivo-tally connected together and form a diamond of rods, two opposite pivots being connected to the plate and the two other pivots each co-operating with a spring.
A favourable embodiment of the hot-gas reci-procating engine according to the invention is character-ized in that two structural components are guided on the shaft, so as to be slidable on said shaft, one of said components being coupled to a point of the plate which is present on one side of the tilting shaft, the other component being coupled to a point of the plate which is present on the other side of the tilting shaft, the two structural components being coupled together by at least two pivotally connected rods of equal length, a spring acting on each of the pivots, the spring constant of all the springs together being substantially equal to `~
the spring constant of the gas forces acting on the plate via the pistons.
So in this manner a mechanical coupling is obtained between the spring mechanism and the plate, -which coupling can give good satisfaction when the centrifugal forces do not play too large a part.
In a further favourable embodiment, the plate is coupled to the spring mechanism via one or more .. - . . . . .
,~:. - : ,- , . . : , ~3S~5~6 liquid columns.
The great advantage of such a hydraulic coupl-ing is that the spring mechanism can he arranged sepa~
rately from the driving mechanism.
In a further favourable embodiment of the engine according to the invention, each of the said springs on its side remote from the spring mechanism is supported by an element wh$ch can be moved in the direction of the spring, means being present to move the spring mecha-nism and plate connected thereto by a displacement of each of the said elements, the spring constant of all the springs together differlng slightly from the spring constant of the gas forces acting on the plate via the pistons. By a displacement of the said elements, a move~
ment of the spring mechanism and the plate coupled there- .'.'!
to takes place.
According to a further embodiment, the movable elements may be constituted by pistons which limit a space to which liquid can be supplied or from which liquid can be removed. In this manner the engine can be con-trolled hydraulically.
In a further embodiment the relevant liquid spaces furthermore comprise a narrow liquid outlet aper-ture. As a result of this, in the stationary condition, the plate can nevertheless be moved again to its posi-I
tion at right angles to the shaft, due to the occurring gas ~orces.
~ ,~
~ ' The invention will now be described in greater detail with reference to the drawing, in which Flg. 1 is a diagrammatic cross-sectional view of a hot-gas engine having a so-called l'swash-plate"
driving mechanism.
Fig. 2 shows diagrammatically an example of a compensation mechanism, and Fig. 3 shows diagrammatically another embodi-ment in which the compensation mechanism is also com-bined with a displacement mechanism.
The hot-gas engine shown in Fig. 1 comprises a number, at least three, of double acting pistons 1 which reciprocate in cylinders 2. Below each of the said pistons there is a cold compression space 3 while above each of the pistons there is a hot expansion space 4.
A number of units each comprising a cooler 5 and a regenerator 6 are arranged between the cylinders 2.
Each of the said units communicates on the cooler side with one cold space 3 in one of the cylin-ders 2 and communicates on the regenerator side with a warm space 4 in another cylinder 2 via a heater 7. In this manner a double-acting hot-gas engine is obtained which is described in detail in Dutch Patent Specifica-; tion 65813, so that further explanation need not be given.
Each of the pistons 1 comprises a driving rod 8 which co-operates with a plate 10 via sliding members 9.
.
, ~3~516 The plate 10 is connected to a shaft 11 in such manner that it can-not rotate relative to the shaft 11 but can tilt about a tilting shaft 12.
In order to cause the plate 13 to move about the tilting shaft, the plate is pivotally connected to a pair of pistons 14-15 at the area 13 on one side of the tilting shaft and to a pair of pistons 17-18 on the other side of the tilting shaft at the area 16.
The pistons 14 and 18 which are present on one side of the plate ld limit a space 19, while the pistons 15-17 present on the other side of the plate lO limit a space 20.
The spaces 19 and 20 can be made to communicate, via a duct 21, with .
- a device which is not shown and with which liquid can be supplied to or removed from the relevant spaces.
During operation of hot-gas engines a gaseous working medium under high pressure is present in the spaces 3 and 4 and the communicatlons there-between, which medium reciprocates between the cold and warm spaces as a result of the movements of the pistons.
The gas forces exerted on the pistons are transferred to the plate 10 via the driving rods 8 and the sliding members 9. Said forces exert on the plate 10 ~: -"' ',~
~`' -,''': ': `'~ ' "`" ~ '.
.~ :
~)3~316 a torque ~Jhich tries to force the plate lO to a position normal to the shaft, Said torque varies substantially linearly with the angleo~and is zero when~ = 0 and is maximum when ~= max, for example 22.
In order to control the supplied power of the engine, either the plate 10 must be moved against the torque or with the torque. In one case this will cost power, whereas in the other case an excess of power is available.
It is the object of the invention to provide a solution in that sense that the plate 10 is balanced in any position, so at any angle ~, so that the move-ment neither in one direction nor in the other direction costs power or provides an excess of power.
This has been achieved by connecting the pair of pistons 14-15 to a structural component 22 which is slidably connected to the shaft 11~ while piston pair ;~
17-18 is connected to a structural component 23 which is also guided on the shaft 11 so as to be slidable.
The structural components 22 and 23 are coupled together by one or more pairs of rods 24-25 which are pivotally coupled together at point 26.
Each of the pivots 26 is connected to a spring 27 which bears at its other end against a dish spring 23 which is rigidly secured to the shaft 11.
The springs 27 are constructed so that together they show a spring characteristic which is equal to the -;: : - ~ . .
~L~3'3.;:~16 characteristic oE the forces exertecl on the structural components 22 and 23 by the piston pairs 14-15 ancl 17-18.
In this manner a compensation mechanism is obtained in ~hich upon moving the plate 10 to its posi-tion at right angles to the shaft, the structural com- -ponents 22 and 23 move towards each other which involves that the springs 27 are compressed so that the energy originating from the plate 10 is stored in said springs.
The energy stored in the springs 27 may afterwards be used again upon moving the plate 10 in the opposite ~ ;~
direction.
The compensation mechanism may be compared with a diamond in the corners of which four identical springs engage. It can be proved theoretically that such a dia-mond is balanced in any position.
This means that the hydraulic liquid which upon moving is supplied to or withdrawn from the spaces 20~ 19 via duct 21, need substantially not supply any movement work ~not couhting friction)~ so that the hot-gas engine can hence be controlled very rapidly.
Instead of a hydraulic system for moving the plate, mechanical means may also be used for this pur-.
pose~ if desired? Due to the direct coupling of the -piston pairs 14-15 and 17-18 with the compensation me chanism, the latter must necessarily also rotate with ;`~
the shaft 11. At high numbers of revolution, such large :
;~
~' .. , ~ . .
. ,. . ,,' :'- '- , ' ''',, ~'; , ', , .' . ` ~: ' centrifugal ~orces may occur as a result~ th~t the compensation effect is adversely influenced. In order to avoid this, a hydraulic coupling may be provided between the plates 10 and the compensation mechanism.
In this case a compensation mechanism as is shown in Fig. 2 may be used. This comprises a diamond of four pivotally connected rods 24~25. Two opposite corners 26 of said diamond are each connected to a spring 27. The two other corners each comprise a piston 30 which limits a space 31 in a cylinder 32. Each of the spaces 31 communicates with the duct 21 via a pipe 33.
For moving the~plate, a ~separate hydraulic system or mechanical means may be used. -The construction is proportioned so that the characteristic of the springs corresponds at least sub-stantially with the variation of the forces exerted by the pistons 30 when said pistons move.
When moving the plAte 10, the volume of the spaces 20 and 19 will vary. This means that the liquid column between the spaces and the pistons 30 moves so that the pistons 30 experience a displacement. When the plate 10 assumes a more inclined position, the pistons 30 will move apart and, conversely3 when moving to the position normal to the shaft, the~pistons move towards each other. The forces exerted by the pistons 30 vary proportionally with the variation of the angle ~5. By ; giving the springs 27 a characteristic which corresponds .~ ` ' .
, . .
1~''3.~
to the forces characteristic, the rod diamond 24~ 25 is balanced in any position. This means that for displacing ; the diamond and plate 10 connected thereto substantially no forces are necessary so that the displacement can be carried out very rapidly. The displacement should be car-ried out hydraulically or mechanically with a separate mechanism.
Fig, 3 shows diagrammatically another embodiment in which the compensation mechanism is also combined with -la displacement mechanism.
The compensation mechanism comprises the same components as that of Fig. 2. The only difference in this case is that the springs 27 are connected to pis-tons 33 which bound a space 34 in a cylinder 35. Further-more,~the spring characteristic of the springs 27 has now been chosen to be slighly different from the forces characteristic exerted~by the pistons 30. ;
When due to the supply of liquid via ducts 36 the pistons 33 are move~, the prestress of-the springs 27 varieS thereby and the rod diamond 24~ 25 is unbalanced, As a result of this the pistons 30 will be displaced until a new equilibrium state is reached.
In order to ensure that with stationary engine `~
the gas forces can force the plate 10 to its position ~ ;
normal to the shaft, each of the cylinders 35 has a narrow aperture 38 through which liquid can leak away so that in the stationary condition the liquid can flow -~
`' .. ,. .. ~ .
:. -. - - , ~ .
~1~3~
away from the spaces 34. This means that the pistons 33 are moved apart as a result of which unbalance of the cliamond rod occurs. In order to restore this, the pis-tons 30 move towards each other so that the plate 10 moves to its position normal to the shaft.
From the above it will be obvious that the above-described invention provides a hot-gas engine having a movable swash-plate driving mechanism of which the plate is coupled to a compensation mechanism which exerts on the plate a torque which is equally large as, is opposite to and vaies in the same manner with the position of the plate as the torque exerted on the plate by the gas forces. This compensation mechanism balances the plate in any position so that the displacement can be carried out without work and hence very rapidly.
In the embodiments the springs are shown as being real mechanical springs; it will be obvious, how-ever, that the springs may also be formed by gas springs, i.e. a piston supported by a gas buffer. ~;~
:
:,:- .. .
:' . : . '., . :.
` ber, co-operates with a plate. The plate is provlded on a rotatably journalled shaft in such a manner that the splate connot perform a rotation relative to the shaft but can tilt about a tilting shaft extending transversely to the centre line of the shaft. Means are also provided to tilt the plate.
Hot-gas reciprocating engines of the above-mentioned type are known ; from the United States Patent Specification 3,511,102. -~
In said known hot-gas reciprocating engine, a variation in the stroke of the pistons co-operating with said plate is effected by tilting the plate about the tilting shaft. This results in a variation of the supplied power in engines and in a variation of the cooling capacity in refrigerators.
During operation of a hot-gas reciprocating engine, a torque always acts on the plate which tries to rotate the plate to the position at right angles to the shaft. The torque is directly proportional to the angle which the plate encloses with the plane perpendicular to the shaft and is substan-tially not dependent on the number of revolutions.
In controlling the power of these machines, the torque co-operates or counteracts, dependent on the increase or decrease of the power.
In order to increase the power tha plate should be moved against the torque. In order to be able to do this rapidly, much power is required which, in certain circumstances, is not available. On the contrary, when .;
decreasing the power, with co-operating torque, there is excessive power.
The excessive power should be stored temporaril~ so that it can be used afterwards.
; . ~
!.
~ 2-.
~3~ 6 I~ is an object of the invention to provide a spring compensation mechanism for a hot-gas reciprocating engille which can be controlled rapidly and with little power.
Accordingly, the apparatus of the invention is a spring compensa-tion mechanism for a swashplate drive, said drive including a drive shaft mounted for rotation about its center line, a tilting shaft extending trans-versely to the center line of the drive shaft, a swashplate tiltably mounted about said tilting shaft and coupled to said drive shaft for rotation there-with, a plurality of driving rods mounted for reciprocating movement r01ative to said drive shaft, said drive rods being coupled to said swashplate such that, the swashplate being tilted at an oblique angle with respect to the drive shaft center line, driving force exerted by said rods against said swashplate imparts rotational torque to said swashplate for rotating said drive shaft, said force also tending to tilt said swashplate toward a position perpendicular to said center line, and means for tilting said swashplate about said tilting shaft, wherein said mechanism comprises a pair of compensating rods, means for coupling one end of each of said rods to the swash plate and for guiding said one ends for movement in a first direction in response to tilting of said swash plate, the other ends of said rods being guided for movement in a direction transverse to said first direction and a spring coupled to said other ends and arranged to be resiliently stressed by movement of said rod other ends in response to tilting of the swashplate, ~;
the spring constant and orientation of said spring being such ~hat stressing -: of the spring produces a change in force proportional to the force change caused by the tendency of said driving rods to tilt said swashplate toward said perpendicular position.
.~
~1 .~
.
1~3~35~6 So in this manner, with downward controlJ a quantity of energy will be stored in the spring mechanism, which energy can be used when increasing the power to vary the position of the plate. As a result of this the control can be carried out rapidl~ and with little power. The spring mechanism may comprise both mechanic and gas spring constructions.
; The rod of the spring mechanism in this construction is in equilib-rium of forces ~balanced) in any position. When the position varies, trans- ;
port of energy will take place from the spring which acts on one end of the rod to the spring co-operating with the other end of the rod. The spring which co-operates with one end of the rod has as it were a negative spring characteristic. ;
In a favourable embodiment the spring mechanism comprises at least one pair of identical rods which are pivotall~ coupled together and in which the free ends of the two rods are straight-guided in the same direction, the pivot being coupled to the plate and the two free ends being each coupled to a spring, or conversely, the spring constant of the two springs together being ^ ' '.
,.
;
s-~6 substantially equal to the spring constant of the gas forces acting on the plate via the piston-like members.
In a further embodiment the spring mechanism comprises at least four identical rods which are pivo-tally connected together and form a diamond of rods, two opposite pivots being connected to the plate and the two other pivots each co-operating with a spring.
A favourable embodiment of the hot-gas reci-procating engine according to the invention is character-ized in that two structural components are guided on the shaft, so as to be slidable on said shaft, one of said components being coupled to a point of the plate which is present on one side of the tilting shaft, the other component being coupled to a point of the plate which is present on the other side of the tilting shaft, the two structural components being coupled together by at least two pivotally connected rods of equal length, a spring acting on each of the pivots, the spring constant of all the springs together being substantially equal to `~
the spring constant of the gas forces acting on the plate via the pistons.
So in this manner a mechanical coupling is obtained between the spring mechanism and the plate, -which coupling can give good satisfaction when the centrifugal forces do not play too large a part.
In a further favourable embodiment, the plate is coupled to the spring mechanism via one or more .. - . . . . .
,~:. - : ,- , . . : , ~3S~5~6 liquid columns.
The great advantage of such a hydraulic coupl-ing is that the spring mechanism can he arranged sepa~
rately from the driving mechanism.
In a further favourable embodiment of the engine according to the invention, each of the said springs on its side remote from the spring mechanism is supported by an element wh$ch can be moved in the direction of the spring, means being present to move the spring mecha-nism and plate connected thereto by a displacement of each of the said elements, the spring constant of all the springs together differlng slightly from the spring constant of the gas forces acting on the plate via the pistons. By a displacement of the said elements, a move~
ment of the spring mechanism and the plate coupled there- .'.'!
to takes place.
According to a further embodiment, the movable elements may be constituted by pistons which limit a space to which liquid can be supplied or from which liquid can be removed. In this manner the engine can be con-trolled hydraulically.
In a further embodiment the relevant liquid spaces furthermore comprise a narrow liquid outlet aper-ture. As a result of this, in the stationary condition, the plate can nevertheless be moved again to its posi-I
tion at right angles to the shaft, due to the occurring gas ~orces.
~ ,~
~ ' The invention will now be described in greater detail with reference to the drawing, in which Flg. 1 is a diagrammatic cross-sectional view of a hot-gas engine having a so-called l'swash-plate"
driving mechanism.
Fig. 2 shows diagrammatically an example of a compensation mechanism, and Fig. 3 shows diagrammatically another embodi-ment in which the compensation mechanism is also com-bined with a displacement mechanism.
The hot-gas engine shown in Fig. 1 comprises a number, at least three, of double acting pistons 1 which reciprocate in cylinders 2. Below each of the said pistons there is a cold compression space 3 while above each of the pistons there is a hot expansion space 4.
A number of units each comprising a cooler 5 and a regenerator 6 are arranged between the cylinders 2.
Each of the said units communicates on the cooler side with one cold space 3 in one of the cylin-ders 2 and communicates on the regenerator side with a warm space 4 in another cylinder 2 via a heater 7. In this manner a double-acting hot-gas engine is obtained which is described in detail in Dutch Patent Specifica-; tion 65813, so that further explanation need not be given.
Each of the pistons 1 comprises a driving rod 8 which co-operates with a plate 10 via sliding members 9.
.
, ~3~516 The plate 10 is connected to a shaft 11 in such manner that it can-not rotate relative to the shaft 11 but can tilt about a tilting shaft 12.
In order to cause the plate 13 to move about the tilting shaft, the plate is pivotally connected to a pair of pistons 14-15 at the area 13 on one side of the tilting shaft and to a pair of pistons 17-18 on the other side of the tilting shaft at the area 16.
The pistons 14 and 18 which are present on one side of the plate ld limit a space 19, while the pistons 15-17 present on the other side of the plate lO limit a space 20.
The spaces 19 and 20 can be made to communicate, via a duct 21, with .
- a device which is not shown and with which liquid can be supplied to or removed from the relevant spaces.
During operation of hot-gas engines a gaseous working medium under high pressure is present in the spaces 3 and 4 and the communicatlons there-between, which medium reciprocates between the cold and warm spaces as a result of the movements of the pistons.
The gas forces exerted on the pistons are transferred to the plate 10 via the driving rods 8 and the sliding members 9. Said forces exert on the plate 10 ~: -"' ',~
~`' -,''': ': `'~ ' "`" ~ '.
.~ :
~)3~316 a torque ~Jhich tries to force the plate lO to a position normal to the shaft, Said torque varies substantially linearly with the angleo~and is zero when~ = 0 and is maximum when ~= max, for example 22.
In order to control the supplied power of the engine, either the plate 10 must be moved against the torque or with the torque. In one case this will cost power, whereas in the other case an excess of power is available.
It is the object of the invention to provide a solution in that sense that the plate 10 is balanced in any position, so at any angle ~, so that the move-ment neither in one direction nor in the other direction costs power or provides an excess of power.
This has been achieved by connecting the pair of pistons 14-15 to a structural component 22 which is slidably connected to the shaft 11~ while piston pair ;~
17-18 is connected to a structural component 23 which is also guided on the shaft 11 so as to be slidable.
The structural components 22 and 23 are coupled together by one or more pairs of rods 24-25 which are pivotally coupled together at point 26.
Each of the pivots 26 is connected to a spring 27 which bears at its other end against a dish spring 23 which is rigidly secured to the shaft 11.
The springs 27 are constructed so that together they show a spring characteristic which is equal to the -;: : - ~ . .
~L~3'3.;:~16 characteristic oE the forces exertecl on the structural components 22 and 23 by the piston pairs 14-15 ancl 17-18.
In this manner a compensation mechanism is obtained in ~hich upon moving the plate 10 to its posi-tion at right angles to the shaft, the structural com- -ponents 22 and 23 move towards each other which involves that the springs 27 are compressed so that the energy originating from the plate 10 is stored in said springs.
The energy stored in the springs 27 may afterwards be used again upon moving the plate 10 in the opposite ~ ;~
direction.
The compensation mechanism may be compared with a diamond in the corners of which four identical springs engage. It can be proved theoretically that such a dia-mond is balanced in any position.
This means that the hydraulic liquid which upon moving is supplied to or withdrawn from the spaces 20~ 19 via duct 21, need substantially not supply any movement work ~not couhting friction)~ so that the hot-gas engine can hence be controlled very rapidly.
Instead of a hydraulic system for moving the plate, mechanical means may also be used for this pur-.
pose~ if desired? Due to the direct coupling of the -piston pairs 14-15 and 17-18 with the compensation me chanism, the latter must necessarily also rotate with ;`~
the shaft 11. At high numbers of revolution, such large :
;~
~' .. , ~ . .
. ,. . ,,' :'- '- , ' ''',, ~'; , ', , .' . ` ~: ' centrifugal ~orces may occur as a result~ th~t the compensation effect is adversely influenced. In order to avoid this, a hydraulic coupling may be provided between the plates 10 and the compensation mechanism.
In this case a compensation mechanism as is shown in Fig. 2 may be used. This comprises a diamond of four pivotally connected rods 24~25. Two opposite corners 26 of said diamond are each connected to a spring 27. The two other corners each comprise a piston 30 which limits a space 31 in a cylinder 32. Each of the spaces 31 communicates with the duct 21 via a pipe 33.
For moving the~plate, a ~separate hydraulic system or mechanical means may be used. -The construction is proportioned so that the characteristic of the springs corresponds at least sub-stantially with the variation of the forces exerted by the pistons 30 when said pistons move.
When moving the plAte 10, the volume of the spaces 20 and 19 will vary. This means that the liquid column between the spaces and the pistons 30 moves so that the pistons 30 experience a displacement. When the plate 10 assumes a more inclined position, the pistons 30 will move apart and, conversely3 when moving to the position normal to the shaft, the~pistons move towards each other. The forces exerted by the pistons 30 vary proportionally with the variation of the angle ~5. By ; giving the springs 27 a characteristic which corresponds .~ ` ' .
, . .
1~''3.~
to the forces characteristic, the rod diamond 24~ 25 is balanced in any position. This means that for displacing ; the diamond and plate 10 connected thereto substantially no forces are necessary so that the displacement can be carried out very rapidly. The displacement should be car-ried out hydraulically or mechanically with a separate mechanism.
Fig, 3 shows diagrammatically another embodiment in which the compensation mechanism is also combined with -la displacement mechanism.
The compensation mechanism comprises the same components as that of Fig. 2. The only difference in this case is that the springs 27 are connected to pis-tons 33 which bound a space 34 in a cylinder 35. Further-more,~the spring characteristic of the springs 27 has now been chosen to be slighly different from the forces characteristic exerted~by the pistons 30. ;
When due to the supply of liquid via ducts 36 the pistons 33 are move~, the prestress of-the springs 27 varieS thereby and the rod diamond 24~ 25 is unbalanced, As a result of this the pistons 30 will be displaced until a new equilibrium state is reached.
In order to ensure that with stationary engine `~
the gas forces can force the plate 10 to its position ~ ;
normal to the shaft, each of the cylinders 35 has a narrow aperture 38 through which liquid can leak away so that in the stationary condition the liquid can flow -~
`' .. ,. .. ~ .
:. -. - - , ~ .
~1~3~
away from the spaces 34. This means that the pistons 33 are moved apart as a result of which unbalance of the cliamond rod occurs. In order to restore this, the pis-tons 30 move towards each other so that the plate 10 moves to its position normal to the shaft.
From the above it will be obvious that the above-described invention provides a hot-gas engine having a movable swash-plate driving mechanism of which the plate is coupled to a compensation mechanism which exerts on the plate a torque which is equally large as, is opposite to and vaies in the same manner with the position of the plate as the torque exerted on the plate by the gas forces. This compensation mechanism balances the plate in any position so that the displacement can be carried out without work and hence very rapidly.
In the embodiments the springs are shown as being real mechanical springs; it will be obvious, how-ever, that the springs may also be formed by gas springs, i.e. a piston supported by a gas buffer. ~;~
:
:,:- .. .
:' . : . '., . :.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A spring compensation mechanism for a swashplate drive, said drive including a drive shaft mounted for rotation about its center line, a tilting shaft extending transversely to the center line of the drive shaft, a swash-plate tiltably mounted about said tilting shaft and coupled to said drive shaft for rotation therewith, a plurality of driving rods mounted for recipro-cating movement relative to said drive shaft, said drive rods being coupled to said swashplate such that, the swashplate being tilted at an oblique angle with respect to the drive shaft center line, driving force exerted by said rods against said swashplate imparts rotational torque to said swashplate for rotating said drive shaft, said force also tending to tilt said swashplate toward a position perpendicular to said center line, and means for tilting said swashplate about said tilting shaft, wherein said mechanism comprises a pair of compensating rods, means for coupling one end of each of said rods to the swash plate and for guiding said one ends for movement in a first direction in response to tilting of said swash plate, the other ends of said rods being guided for movement in a direction transverse to said first direction and a spring coupled to said other ends and arranged to be resiliently stressed by movement of said rod other ends in response to tilt-ing of the swashplate, the spring constant and orientation of said spring being such that stressing of the spring produces a change in force proportional to the force change caused by the tendency of said driving rods to tilt said swashplate toward said perpendicular position.
2. A mechanism as claimed in claim 1, wherein said two compensating rods have said other ends pivotally connected together and said means for coupling comprises first and second components guided for axial movement parallel to said drive shaft, the first component coupled to the swashplate at a location to one side of the tilting shaft and the second component coupled to the swashplate at a location to the other side of the tilting shaft so that said components move in opposite directions for a given tilting movement, respective components being each pivotally connected to a respec-tive one end of a compensating rod.
3. A mechanism as claimed in claim 2 wherein said locations are equi-distant from the tilting shaft and said mechanism includes at least four compensating rods of identical length pivotally connected to constitute a diamond of rods, two opposite pivots being connected to respective components, the other pivots being each connected to a respective spring, the spring constant of the springs together being substantially equal to the spring constant of the force tending to tilt the swashplate toward said perpendicular position.
4. A mechanism as claimed in claim 1, wherein said two compensating rods have said other ends pivotally connected together and said means for coupling comprises first and second components guided for axial movement parallel to said drive shaft, the first component coupled to the swashplate at a location to one side of the tilting shaft and the second component coupled to the swashplate at a location to the other side of the tilting shaft so that said components move in opposite directions for a given tilting movement, and single liquid duct means for moving said respective one ends in response to movement of said components with respect to each other.
5. In a hot gas reciprocating engine, a drive shaft mounted for rotation about its center line, a tilting shaft extending transversely to the center line of the drive shaft, a swashplate tiltably mounted about said tilting shaft and coupled to said drive shaft for rotation therewith, a plurality of piston-like members, a corresponding plurality of driving rods mounted for reciprocating movement relative to said drive shaft, said driving rods being coupled to said swashplate such that, the swashplate being tilted at an oblique angle with respect to the drive shaft center line, driving force exerted by said rods against said swashplate imparts rotational torque to said swashplate for rotating said drive shaft, said force also tending to tilt said swashplate toward a position perpendicular to said center line, and means for tilting said swashplate about said tilting shaft, a spring compensation mechanism comprising two compensating rods each having one end and another end, said other ends pivotally connected together; means for coupling said one ends of said compensating rods to the swashplate and for guiding said one ends for movement in a first direction in response to tilting of said swashplate, said coupling means comprising first and second components guided for axial movement parallel to said drive shaft, the first component coupled to the swashplate at a location to one side of the tilting shaft and the second component coupled to the swashplate at a location to the other side of the tilting shaft so that said components move in opposite directions for a given tilting movement, means for coupling said components to move said one ends toward each other in response to tilting of the swash-plate toward the perpendicular position; means for guiding said other ends of said rods for movement in a direction transverse to said first direction;
and a spring coupled to said other end and arranged to be resiliently stressed by movement of said rod other end in response to tilting of the swashplate, the spring constant and orientation of said spring being such that stressing of the spring produces a change in force proportional to the force change caused by the tendency of said driving rods to tilt said swashplate toward said perpendicular position.
and a spring coupled to said other end and arranged to be resiliently stressed by movement of said rod other end in response to tilting of the swashplate, the spring constant and orientation of said spring being such that stressing of the spring produces a change in force proportional to the force change caused by the tendency of said driving rods to tilt said swashplate toward said perpendicular position.
6. An engine as claimed in claim 5, wherein said locations are equally distant from the tilting shaft, comprising at least four compensating rods of identical length pivotally connected to constitute a diamond of rods, two opposite pivots being pivotally connected to said respective components, the other pivots being each connected to a respective spring, the spring constant of the springs together being substantially equal to the spring constant of the force tending to tilt the swashplate toward said perpendicular position.
7. An engine as claimed in claim 5, wherein said means for coupling said components includes single liquid duct means for moving said respective one ends in response to movement of said components with respect to each other.
8. An engine as claimed in claim 7, comprising at least four compensat-ing rods of identical length pivotally connected to constitute a diamond of rods, means connected to said single liquid duct means for moving two opposite pivots in said first direction, the other pivots being each connected to a respective spring, the spring constant of the springs together being sub-stantially equal to the spring constant of the force tending to tilt the swashplate toward said perpendicular position.
9. An engine as claimed in claim 5, wherein said spring mechanism includes a plurality of springs, each of said springs at an end remote from said compensating rods being supported by an element which can be moved in the direction of the spring; and means for displacing said spring mechanism and tilting said swashplate by displacing each of said elements, the spring constant of all the springs together differing slightly from the spring con-stant of the gas forces acting on the plate by said pistons.
10. An engine as claimed in claim 5, wherein each of said elements includes means for displacing the respective spring responsive to supply and removal of liquid from a space; and said elements further include a bleeding aperture connected to said space through which liquid can flow away from the space.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7414457A NL7414457A (en) | 1974-11-06 | 1974-11-06 | HOT GAS VACUUM MACHINE. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1039516A true CA1039516A (en) | 1978-10-03 |
Family
ID=19822399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA238,907A Expired CA1039516A (en) | 1974-11-06 | 1975-11-03 | Hot-gas reciprocating engine |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5426654B2 (en) |
| CA (1) | CA1039516A (en) |
| DE (1) | DE2547831C3 (en) |
| FR (1) | FR2290577A1 (en) |
| GB (1) | GB1531136A (en) |
| IT (1) | IT1048757B (en) |
| NL (1) | NL7414457A (en) |
| SE (1) | SE421817B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6993950B2 (en) * | 2018-09-28 | 2022-01-14 | Ｋｙｂ株式会社 | Hydraulic rotary machine |
-
1974
- 1974-11-06 NL NL7414457A patent/NL7414457A/en not_active Application Discontinuation
-
1975
- 1975-10-25 DE DE19752547831 patent/DE2547831C3/en not_active Expired
- 1975-10-27 GB GB4410975A patent/GB1531136A/en not_active Expired
- 1975-11-01 JP JP13207775A patent/JPS5426654B2/ja not_active Expired
- 1975-11-03 IT IT2897575A patent/IT1048757B/en active
- 1975-11-03 SE SE7512276A patent/SE421817B/en not_active IP Right Cessation
- 1975-11-03 CA CA238,907A patent/CA1039516A/en not_active Expired
- 1975-11-05 FR FR7533823A patent/FR2290577A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE2547831B2 (en) | 1977-08-25 |
| DE2547831A1 (en) | 1976-05-20 |
| SE421817B (en) | 1982-02-01 |
| DE2547831C3 (en) | 1978-04-27 |
| GB1531136A (en) | 1978-11-01 |
| FR2290577A1 (en) | 1976-06-04 |
| IT1048757B (en) | 1980-12-20 |
| NL7414457A (en) | 1976-05-10 |
| JPS5426654B2 (en) | 1979-09-05 |
| SE7512276L (en) | 1976-05-07 |
| JPS5169739A (en) | 1976-06-16 |
| FR2290577B1 (en) | 1980-09-12 |
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