The invention pertains to a parallel crank drive, particularly to a parallel crank drive for an internal combustion engine with a variable compression ratio, to an internal combustion engine with a variable compression ratio and to a manual transmission, particularly to a manual transmission for an internal combustion engine with a variable compression ratio.
EP 1 082 548 B1 describes a parallel crank drive that is referred to as a clutch element and designed for an internal combustion engine with a displaceable crankshaft in order to vary the compression ratio, wherein this parallel crank drive features a first and a second clutch body that are referred to as rotary bodies and coupling elements that are referred to as crank elements. The rotary bodies can be respectively connected to a first and a second shaft. The respective crank elements are rotatably supported on both rotary bodies. In this known clutch element, the two rotary bodies are aligned in parallel planes of rotation and can be respectively connected to the mutually assigned shaft ends of the crankshaft and the output shaft. The crankshaft and the output shaft are arranged one behind the other in an axially parallel fashion with an eccentricity, and the crank elements that connect both rotary bodies have a crank radius that corresponds to the eccentricity and are spaced apart from one another in the circumferential direction. The second rotary body that is connected to the output shaft features two partial bodies that are rigidly connected to one another and referred to as disk elements, wherein the first rotary body that is connected to the crank shaft and also realized in a disk-shaped fashion is arranged between said partial bodies. The two disk elements are rigidly connected to one another on their outer edges by means of screws. The crank elements are supported on the first rotary body and the two disk elements of the second rotary body by means of rolling bearings or even sliding bearings. Due to this housing-like design of the second rotary body, the interior space defined by the two disk elements is realized in the form of an oil chamber that is connected to the engine oil circuit. During operation, this space is filled across the entire circumference under the influence of centrifugal force such that oil is supplied through lubricating channels assigned to the individual bearings of the crank elements.
This known parallel crank drive has the disadvantage that the oil remains in the interior space of the second rotary body up to almost the center of the crankshaft and therefore generates correspondingly high friction during the operation.
The invention is based on the objective of developing a parallel crank drive that features lower frictional losses.
This objective is attained with a parallel crank drive according to claim 1 or according to claim 9 or according to claim 11. Other embodiments are described in the dependent claims.
The invention proposes a parallel crank drive, particularly for an internal combustion with variable compression ratio, featuring a first and a second clutch body that can be connected to a first and a second shaft, respectively, at least one coupling element that is rotatably supported on both clutch bodies, and a housing that encloses the clutch bodies and the coupling element.
The housing makes it possible, for example, to modify the above-described parallel crank drive according to EP 1 082 548 B1, the full disclosure of which is incorporated herein by reference, in such a way that the known closed, housing-like design of the second clutch body is replaced with an open design. Starting with the known closed, housing-like design, this open design can be achieved in that the first disk element or partial body situated near the second shaft and/or the second disk element or partial body situated near the first shaft features at least one opening. The oil can exit the interior space defined by the two disk elements through this opening. The openings are preferably arranged in the end faces and/or circumferential surfaces of the disk elements. The openings furthermore result in a reduction of the mass and of the moment of inertia of the second clutch body and of the parallel crank drive. In addition, the recessed bores for the clutch elements in the two disk elements can now be realized in the form of through-bores, wherein this represents a significant simplification in comparison with the blind bores provided in known disk elements for tightness reasons. Furthermore, a seal is no longer required between the two disk elements. The housing also makes it possible, for example, to modify the above-described parallel crank drive known from EP 1 082 548 B1 in such a way that the known two-part design of the second clutch body featuring the two disk elements is replaced with a one-part design, in which the second disk element situated near the first shaft is eliminated.
The housing may be realized in any required fashion. For example, it may be formed by a crankcase of the internal combustion engine or a transmission case of a manual transmission. In this case, the parallel crank drive consequently is situated in the interior of the crankcase or transmission case. However, the housing may also be formed by a wall of a crankcase of an internal combustion engine or a wall of a transmission case of a manual transmission and by a cover that is connected to the wall. In this case, it would be possible, for example, to realize the cover integrally with the wall or to screw the cover to the wall.
It would be possible to support the second clutch body on the housing in the region of the first shaft and/or in the region of the second shaft. This may be realized, for example, with the aid of sliding bearings and/or rolling bearings. The bearings preferably consist of single-row or double-row bearings. The two-sided support, i.e., the support in the region of the first shaft and in the region of the second shaft, is preferably utilized if the parallel crank drive is realized in the form of a dual mass flywheel, in which the first and the second clutch body respectively form the primary flywheel mass and the secondary flywheel mass of the dual mass flywheel.
It would be possible to provide a seal relative to the first shaft, preferably with the aid of a rotary shaft seal, and to provide the coupling element with a lifetime grease filling. The rotary shaft seal prevents oil from being admitted into the parallel crank drive from the main bearing of the first shaft that lies closest to the parallel crank drive. The lubrication of the coupling element bearings with such oil is also unnecessary due to the lifetime grease filling. In this case, the housing that encloses the clutch bodies and coupling elements may also be completely eliminated.
It would be possible to provide the housing with at least one oil drain opening. The oil drain opening is preferably connected to an oil pan of an internal combustion engine or to a transmission case of a manual transmission.
The invention furthermore proposes a parallel crank drive, particularly for an internal combustion with variable compression ratio, featuring a first and a second clutch body that can be connected to a first and a second shaft, respectively, at least one coupling element that is rotatably supported on both clutch bodies, and an oil collector that completely encloses the clutch bodies in the circumferential direction.
Analogous to the above-described housing, this oil collector makes it possible, for example, to realize the above-described open design of the second clutch body featuring the two disk elements and the above-described one-part design of the second clutch body, in which the second disk element is eliminated.
The oil collector is preferably sealed relative to the clutch bodies by means of a labyrinth and/or by means of slip rings.
The invention furthermore proposes a parallel crank drive, particularly for an internal combustion engine with variable compression ratio, featuring a first and a second clutch body that can be connected to a first and a second shaft, respectively, at least one coupling element that is rotatably supported on both clutch bodies, and an oil collector that partially encloses the clutch bodies in the circumferential direction, wherein the first and/or the second clutch body feature(s) at least one oil outlet opening, and wherein a closing device for the oil outlet opening is provided and realized in such a way that the oil outlet opening is opened when it sweeps over the oil collector and is otherwise closed.
Analogous to the above-described housing and the above-described oil collector, this oil collector makes it possible to realize, for example, the above-described open design of the second clutch body featuring the two disk elements and the above-described one-part design of the second clutch body, in which the second disk element is eliminated.
The oil collector may be arranged in any required position in the circumferential direction. It is preferably arranged underneath the two clutch bodies. In this case, the oil collector is also able to collect the oil flowing out of the oil outlet opening while the clutch bodies are at a standstill.
Each of the proposed oil collectors may feature at least one oil drain opening. The oil drain opening is preferably connected to an oil pan of an internal combustion engine or to a transmission case of a manual transmission.
In each of the proposed parallel crank drives, at least one oil supply channel may extend up to the coupling element in the first shaft and the first clutch body. The oil supply channel may be connected, for example, to the oil supply for a bearing of the first shaft such that the oil reaches the coupling element and its bearings in the two clutch bodies directly through this oil supply channel.
In each of the proposed parallel crank drives, the first and/or the second clutch body may feature at least one opening. This opening was already described in greater detail above.
In each of the proposed parallel crank drives, the second clutch body may feature a first partial body situated near the first shaft and a second partial body situated near the second shaft that are mounted one on the other with at least one mounting element, wherein this mounting element extends between the surfaces of the partial bodies that face one another and its radial distance from the second shaft is smaller or equal to the radial distance of at least one coupling element from the second shaft, and wherein the first clutch body is arranged between the partial bodies and features at least one opening through which the mounting element protrudes. The two partial bodies may be shaped as required and are preferably realized in a disk-shaped fashion. The second clutch body featuring the two partial bodies is also realized in two parts, wherein this two-part design was already described in greater detail above. In contrast to the above-described two-part design according to EP 1 082 548 B1 in which the two disk elements or partial bodies are rigidly connected to one another at their outer edges with the aid of screws, the two partial bodies of the proposed second clutch body are mounted one on the other at locations that lie farther radially inward with the aid of mounting elements. Consequently, the outside diameter of the proposed partial bodies can be significantly reduced in comparison with these known disk elements such that the mass and the moment of inertia of the second clutch body and of the parallel crank drive are reduced accordingly.
Each of the proposed parallel crank drives may be realized in the form of a flywheel, preferably a dual mass flywheel. The first and the second clutch body preferably form the primary flywheel mass and the secondary flywheel mass of the dual mass flywheel.
The invention furthermore proposes an internal combustion engine with variable compression ratio featuring a pivotably supported crankshaft, an output shaft and one of the proposed parallel crank drives between the crankshaft and the output shaft.
The invention also proposes an internal combustion engine with variable compression ratio featuring a pivotably supported crankshaft, an output shaft, a parallel crank drive between the crankshaft and the output shaft and a housing that encloses the parallel crank drive.
In each of the proposed internal combustion engines, the housing may be formed by a crankcase of the internal combustion engine.
In each of the proposed internal combustion engines, the housing may be formed by a wall of a crankcase of the internal combustion engine and a cover that is connected to the wall. In this case, it would be possible, for example, to realize the cover integrally with the wall or to screw the cover to the wall.
In each of the proposed internal combustion engines, the parallel crank drive may feature a first and a second clutch body that are connected to the crankshaft and the output shaft, respectively, and at least one coupling element that is rotatably supported on both clutch bodies. The crank radius of the coupling element can be, for example, at a right angle to the two shafts.
In each of the proposed internal combustion engines, the parallel crank drive may be realized in the form of a flywheel, preferably a dual mass flywheel.
In each of the proposed internal combustion engines, a flywheel, preferably a dual mass flywheel, may be incorporated between the parallel crank drive and the output shaft.
In each of the proposed internal combustion engines, the housing may feature at least one oil drain opening that is connected to an oil pan of the internal combustion engine.
The invention furthermore proposes a manual transmission, particularly for an internal combustion engine with variable compression ratio, featuring an input shaft that can be connected to a pivotably supported crankshaft and one of the proposed parallel crank drives between the crankshaft and the input shaft.
The invention also proposes a manual transmission, particularly for an internal combustion engine with variable compression ratio, featuring an input shaft that can be connected to a pivotably supported crankshaft, a parallel crank drive between the crankshaft and the input shaft and a housing that encloses the parallel crank drive.
The preceding explanations regarding the proposed parallel crank drives and internal combustion engines also apply accordingly to the proposed manual transmissions.
In each of the proposed manual transmissions, the housing may be formed by a transmission case of the manual transmission.
In each of the proposed manual transmissions, the housing may be formed by a wall of a transmission case of the manual transmission and a cover that is connected to the wall. In this case, the cover may, for example, be realized integrally with the wall or screwed to the wall.
In each of the proposed manual transmissions, the parallel crank drive may feature a first clutch body that can be connected to the crankshaft, a second clutch body that can be connected to the input shaft and at least one coupling element that is rotatably supported on both clutch bodies. The crank radius of the coupling element may be, for example, at a right angle to the shafts.
In each of the proposed manual transmissions, the parallel crank drive may be realized in the form of a flywheel, preferably a dual mass flywheel.
In each of the proposed manual transmissions, a flywheel, preferably a dual mass flywheel, may be incorporated between the crankshaft and the parallel crank drive.
In each of the proposed manual transmissions, a starting clutch may be provided between the crankshaft and the parallel crank drive or between the parallel crank drive and the input shaft.
Other advantageous embodiments of the invention are described in greater detail below with reference to the drawings. However, the individual characteristics shown are not restricted to the respective embodiments, but can also be combined with other individual characteristics described above or with individual characteristics of other embodiments such that additional embodiments are formed. The details in the drawings should merely be interpreted in an explanatory, but not in a restrictive sense. Shown are:
In this case, the parallel crank drive 10 features a first clutch body 20, a second clutch body 21, six coupling elements 22 that are illustrated quite well in
The coupling elements 22 consist of cranks in this case, but may also be realized differently, for example, with the aid of gears. Each coupling element 22 features a cylindrical center disk 26 and a pin 27 that is arranged eccentric and axially parallel thereto, wherein the pin has a smaller diameter than the center disk 26 and protrudes from both end faces of the center disk 26. The center disk axis 28 of the center disk 26 and the pin axis 29 of the pin 27 extend parallel to the crankshaft axis 18 and the output shaft axis 18 and have an eccentricity, i.e., a distance between one another that is identical to the eccentricity of the crankshaft axis 18 and the output shaft axis 19. This is illustrated quite well in
In this case, the housing 23 is formed by the wall 13 and a cover 31 that is connected to the wall 13 with the aid of screws. The second clutch body 21 is supported on the housing 23 in the region of the crankshaft 14 and in the region of the output shaft. For this purpose, the inner edge of the first partial body 24 with the shape of a circular ring is supported radially inward on an axial collar of the wall 13 in the region of the shaft journal 16 with the aid of a first roller bearing 32 and the central flange region of the second partial body 25 is supported radially outward on an inner circumferential surface of a central through-opening of the cover 31 with the aid of a second roller bearing 33. The second clutch body 21 is supported on both sides of the first clutch body 20 and therefore is secured against tilting. A ring seal 34 that prevents oil from leaking out of the housing 23 of the parallel crank drive 10 is provided on the transmission side of the second roller bearing 33 that faces away from the crankshaft 14, i.e., on the right side of the second roller bearing in
In its not-shown bottom region, the cover 31 features a not-shown oil drain opening that is connected to a not-shown oil pan of the internal combustion engine 11. Consequently, the oil collected by the housing 23 can be routed back to the oil pan through the oil drain opening.
Each mounting element 35 features two mutually aligned elevations 36 that protrude axially inward from the facing inner surfaces of the two partial bodies 24, 25 and are screwed to one another. In the region of each mounting element 35, the first clutch body 20 arranged between the partial bodies 24, 25 features an opening 37 through which the corresponding mounting element 35 protrudes. The openings 37 are shaped such that they do not impair the relative movement between the two clutch bodies 20, 21 during the operation and while the crankshaft 14 is pivoted.
In addition, a second ring seal 38 is provided radially within the first roller bearing 32 between the collar of the wall 13 and the flange of the crankshaft 14 in this second embodiment. This prevents engine oil from leaking out of the crankcase 12 and into the parallel crank drive 10. The oil supply channel 30 of the first embodiment is not provided in this case because the lubrication of the coupling elements 22 is realized differently, e.g., due to the fact that they move through a not-shown oil sump, wherein the oil drain opening that is provided in the first embodiment and that is connected to the oil pan is also eliminated in this case.
In this fourth embodiment, the second clutch body 21 furthermore features several openings that are distributed over its circumference and that serve as oil outlet openings 44 for the oil collected in the interior of the second clutch body 21 realized in the form of a hollow disk as in the first embodiment. With respect to these oil outlet openings 44,
A closing device 45 is provided for each oil outlet opening 44 and realized in such a way that the corresponding oil outlet opening 44 is opened when it sweeps over the oil collector 39 and is otherwise closed. For this purpose, it features a valve pin 46 that cooperates with a ridge 47 protruding radially inward from the bottom of the oil collector 39. The valve pin 46 is seated in the oil outlet opening 44 and its diameter is smaller than that of the oil outlet opening. On the radially inner end, i.e., on the upper end in
This application is the U.S. national phase of PCT/EP2007/011476 filed Dec. 31, 2007, the entirety of which is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP07/11476 | 12/31/2007 | WO | 00 | 6/30/2010 |