Hub-hub connection for a power unit

Abstract

The invention relates to a power unit, in particular for a hybrid vehicle, including a reciprocating-piston engine and at least one generator drivingly connected to the engine, wherein the engine has at least two pistons guided in at least two cylinders in a tandem arrangement, and two crankshafts, which are connected to the pistons by connection rods that run in opposite directions, and are mechanically coupled in the same phase. The engine includes a hub-hub connection with a first connection joining a first hub to a second hub such that an angular position between the first hub and the second hub is continuously adjustable on installation. The hub-hub connection also has a second connection in the form of a connection disk configured, dimensioned and arranged with support surfaces, on each of which the first hub and the second hub rest. The connection disk has a matrix with hard material elements embedded therein, in particular diamond chips, which are arranged in the support surfaces for frictional engagement of the hubs.

Claims

1. A power unit comprising: a reciprocating-piston engine (engine) having at least one generator drivingly connected to the engine, the engine including a first hub coupled to a second hub by a first connection; at least two pistons included in the engine guided in at least two cylinders arranged in tandem; first and second crankshafts connected to the pistons by connection rods running in opposite directions and mechanically coupled in a same phase; and a connection disk configured, dimensioned and arranged as a second connection for transmitting torque from the first hub to the second hub such that an angular position between the hubs is continuously adjustable on installation, wherein the first hub and the second hub rest on each of a plurality of surfaces of the connection disk, and wherein the surfaces of the connection disk include a matrix of hard materials for frictional engagement of the hubs.

2. The power unit of claim 1, wherein the frictional engagement is by one of a screw screwed into an inner thread of the first hub or a hub nut screwed with an outer thread of the first hub.

3. The power unit of claim 2, wherein the one of the screw or the hub nut pass through the connection disk.

4. The power unit of claim 2, wherein the one of the screw or the hub nut exert force in a longitudinal direction against the connection disk.

5. The power unit of claim 2, wherein the screw is tightened in a direction against the transmission of torque from the first hub to the second hub.

6. The power unit of claim 1, wherein the first hub and the second hub form parallel facing surfaces resting on the connection disk.

7. The power unit of claim 1, wherein the first hub includes at least one of the crankshafts and the second hub includes one of a sprocket or a belt wheel.

8. The power unit of claim 1, wherein the at least one generator is connected to an output hub of the engine by one of a gearwheel mechanism or a traction mechanism.

9. The power unit of claim 8, wherein the traction mechanism is one of a toothed chain or a toothed belt.

10. The power unit according to claim 8, wherein the first crankshaft rotates in a first direction and the second crankshaft rotates in a second direction opposite the first direction, wherein the at least one generator is rotatable in the first direction, wherein a balance shaft is rotatable in the second direction and is drivingly connected with the second crankshaft, and wherein a flywheel mass is carried by one of the balance shaft or the second crankshaft.

11. A power unit comprising: a reciprocating-piston engine (engine) having at least one generator drivingly connected to the engine, the engine including a first hub coupled to a second hub by a first connection; at least two pistons included in the engine guided in at least two cylinders arranged in tandem; first and second crankshafts connected to the pistons by connection rods running in opposite directions and mechanically coupled in a same phase; and a connection disk configured, dimensioned and arranged as a second connection for transmitting torque from the first hub to the second hub such that an angular position between the hubs is continuously adjustable on installation, wherein the first hub and the second hub rest on each of a plurality of surfaces of the connection disk, and wherein the surfaces of the connection disk include a matrix of hard materials for frictional engagement of the hubs, wherein the frictional engagement is by one of a screw screwed into an inner thread of the first hub or a hub nut screwed with an outer thread of the first hub.

12. The power unit of claim 11, wherein the one of the screw or the hub nut pass through the connection disk.

13. The power unit of claim 11, wherein the one of the screw or the hub nut exert force in a longitudinal direction against the connection disk.

14. The power unit of claim 11, wherein the screw is tightened in a direction against the transmission of torque from the first hub to the second hub.

15. The power unit of claim 11, wherein the first hub and the second hub form parallel facing surfaces resting on the connection disk.

16. The power unit of claim 11, wherein the first hub includes at least one of the crankshafts and the second hub is an output hub having one of a sprocket or a belt wheel.

17. The power unit of claim 16, wherein the at least one generator is connected to the output hub by one of a gearwheel mechanism or a traction mechanism.

18. The power unit of claim 17, wherein the traction mechanism is one of a toothed chain or a toothed belt.

19. A power unit comprising: a reciprocating-piston engine (engine) having first and second generators connected to the engine via first and second crankshafts respectively, the engine including at least two pistons guided in at least two cylinders arranged in tandem, the crankshafts connected to the pistons by connection rods running in opposite directions and mechanically coupled in a same phase; a first hub coupled to a second hub included in the engine by a first connection; and a connection disk configured, dimensioned and arranged as a second connection for transmitting torque from the first hub to the second hub such that an angular position between the hubs is continuously adjustable on installation, wherein the first hub and the second hub rest on each of a plurality of surfaces of the connection disk, and wherein the surfaces of the connection disk include a matrix of hard materials for frictional engagement of the hubs.

Description

(1) The invention is explained more closely below with further details with reference to the enclosed schematic drawings. There are shown therein:

(2) FIG. 1 a perspective view of a coated connection disc according to an example embodiment according to the invention in accordance with claim 1;

(3) FIG. 2 a partial section through a reciprocating-piston engine for a power unit according to an example embodiment according to the invention along the rotation axis of a crankshaft;

(4) FIG. 3 a frontal section through a power unit according to an example embodiment according to the invention;

(5) FIG. 4 a power unit according to an example embodiment according to the invention, wherein the flywheel mass element is carried by the balance shaft; and

(6) FIG. 5 a power unit according to a further example embodiment according to the invention, wherein the flywheel mass element is carried by the second crankshaft.

(7) FIG. 1 shows a perspective view of a coated connection disc for a power unit according to the invention in accordance with claim 1. The connection disc 10 is embodied in a ring-shaped and flat manner. It has a right-side and left-side support surface 12. In the middle, a central opening 14 is arranged, through which a screw 20 for fastening between sprocket 21 and crankshaft 22 can extend through the connection disc 10.

(8) Generally, the connection disc 10 can have a coating 11. The coating 11 intensifies here the frictional engagement between the hub-hub connection according to the invention.

(9) In a preferred embodiment, the connection disc 10 has a coating 11 with hard material elements embedded therein. The connection disc 10 can be coated on a right-side or left-side support surface 12 or advantageously on both support surfaces 12. Ideally, the coating 11 has diamond chips. An increased frictional engagement is thus guaranteed. The coating 11 can cover the connection disc 10 partially or completely. The layer thickness of the coating 11 can be greater here than the thickness of the connection disc 10. Generally it applies that a thicker layer of the connection disc 10 enables an increased frictional engagement.

(10) FIG. 2 shows a partial section through a reciprocating-piston engine for a power unit according to an example embodiment according to the invention. The section runs through a cylinder 29 and through the rotation axis of a crankshaft 22. The reciprocating-piston engine has a crankshaft housing 26. A crankshaft 22 is arranged in the lower part of the crankshaft housing 26. The crankshaft 22 can be surrounded by an oil collecting region 27 beneath the crankshaft 22.

(11) The crankshaft 22 comprises for example two crank webs 23. A crank pin 23a is arranged on the left-side crank web 23.

(12) The left-side crank web 23 and the crank pin 23a have centrally a bore for a screw 20. A sprocket 21 is fastened to the crank web 23 in a non-rotatable and force-fitting manner by the screw 20. The sprocket 21 has a sprocket hub 21a on the side facing the crankshaft 22. The bore runs horizontally through the crank web 23 and the crank pin 23a and centrally through the sprocket 21 and the sprocket hub 21a. The screw 20, proceeding from the sprocket 21, thus opens into the crank web 23. The screw 20 thus lies in a recessed manner in the sprocket 21.

(13) The screw thread can extend through the crank web 23 and the crank pin 23a. Furthermore, the screw thread can extend up into the sprocket hub 21a. The bore runs for example almost through the entire length of the crank web 23. The screw diameter here is preferably approximately as great as the crank pin 23a. In particular, the screw diameter can have a size which corresponds to between 50% and 80% the size of the crank pin diameter. This increases the stability of the hub-hub connection.

(14) The screw 20 extends centrally through the connection disc 10. In particular, the screw 20 and the connection disc 10 are coaxially arranged. An axial pressure force of the screw 20 acts thereby onto the connection disc 10. The connection disc 10 has a right-side and left-side support surface 12, on which respectively a face surface 13a of the crank pin 23a and a face surface 13 of the sprocket hub 21a rest. The connection disc 10 has the same diameter as the face surface 13a of the crank pin 23a and the face surface 13 of the sprocket hub 21a.

(15) On the crankshaft 22 several crankshaft bearings 24 are arranged, which are configured as roller bearings 25. The roller bearing 25 comprises an inner ring 25a and an outer ring 25b. A round rolling body 25d is arranged centrally between inner ring 25a and outer ring 25b. On the side of the crankshaft 22 facing the sprocket hub 21a a roller bearing 25 is arranged, which is secured by a securing element 25c. The securing element 25c is arranged between the roller bearing 25 and the sprocket 21.

(16) The roller bearing 25 surrounds the sprocket hub 21a, the crank pin 23a and the connection disc 10.

(17) An outer circumferential area of the connection disc 10 thus adjoins the inner ring 25a of the roller bearing 25.

(18) The connection rod bearing 30 is arranged on the crankshaft 22 between the crank webs 23. The connection rod bearing 30 connects the crankshaft 22 with a connection rod 31. The crankshaft 22 has the task here of receiving forces which are directed via the connection rod 31, and of converting these into a torque. The torque can then be passed on to a generator 40.

(19) The connection rod 31 is connected to a piston 44, not illustrated, which can carry out an oscillating movement in a cylinder 29 and thereby exerts pressure onto the fuel mixture which is present in the cylinder 29.

(20) FIG. 3 represents a frontal section through a power unit according to the invention with a reciprocating-piston engine. The reciprocating-piston engine has two crankshafts and two cylinders 29 in a tandem arrangement. The cylinders 29 are arranged parallel to one another here. On the crankshafts 22 sprockets 21 are arranged, which are in engagement with one another and bring about an oppositely directed drive of the crankshafts 22 which are mechanically coupled in the same phase.

(21) The connection rods 31 are articulatedly connected with respectively a piston 44, which is guided respectively in one of the two parallel cylinders 29. The connection rods 31 can carry out here an oscillating movement in upward and downward direction.

(22) Above the cylinders 29, inlet and outlet valves 45, 46 are arranged which are respectively connected with an inlet and outlet channel. During the various ignition strokes of the reciprocating-piston engine, the valves are operated for example by a camshaft by means of control rods and rocker arms.

(23) The crankshafts 22 are connected respectively by means of a traction means, not illustrated, for example a chain, a toothed chain or a toothed belt, to one of the two generators 40. Above the two generators 40 respectively a receiving space 41 for electronics is arranged. Such a power unit with a reciprocating-piston engine, and two generators 40 is advantageously able to be used as a drive unit of a hybrid vehicle. The hub-hub connection according to the invention can be arranged for example between the crankshaft and the sprocket or between a generator and a gear drivingly connected therewith.

(24) In FIG. 4 a power unit according to an example embodiment according to the invention is shown, which is formed essentially by a reciprocating-piston engine, a generator 40 and a balance shaft 49. The reciprocating-piston engine has two cylinders 29 arranged in tandem form, in particular parallel to one another. In the cylinders 29, pistons 44 are guided which are articulatedly coupled by means of connection rods 31 respectively with a crankshaft 47, 48. The crankshafts 47, 48 are rotatable in opposite directions and have respectively on the face side gears 50, 51 which engage into one another, in order to thus synchronize the movement of the pistons 44. Preferably, provision is made that the distance between the articulated connections between the connection rods 31 and the pistons 44 is smaller than the distance of the crankshaft axes with respect to one another. The cylinders 29 are therefore arranged in an inwardly offset manner with respect to the crankshafts 47, 48. This leads to the fact that in a top dead centre of the pistons, the connection rods 31 are at a slight angle with respect to the crankshaft axes, whereby the piston skirt friction reduces. This results in a particularly quiet engine start.

(25) In the example embodiment according to FIG. 4, a flywheel mass element 52 is fastened on the balance shaft 49. In particular, the balance shaft 49 carries the flywheel mass element 52. The flywheel mass element 52 is connected to the balance shaft 49 in a non-rotatable manner. In this embodiment of the power unit on the generator 40 and the balance shaft 49, the mounted gears or respectively pulleys, which are in engagement with respective traction means 50, 51, are equipped with the same diameters. This leads to the fact that the generator 40 and the balance shaft 49 rotate with the same rotation speed, so that the rotating mass of the generator 40 and the rotating flywheel mass of the flywheel mass element 52 balance each other out. In this way, in particular, moments of mass inertia of the second order are balanced out.

(26) In the example embodiment according to FIG. 5, the flywheel mass element 52 is arranged on the second crankshaft 48. In particular, the second crankshaft 48 carries the flywheel mass element 52. However, the coupling of the flywheel mass element 52 with the second crankshaft 48 takes place preferably indirectly by means of a transmission gearing, so that the flywheel mass element 52, in operation, rotates with twice the speed with respect to the second crankshaft 48.

REFERENCE LIST

(27) 10 connection disc 11 coating 12 support surface 13 face surface sprocket hub 13a face surface crank pin 14 opening 20 screw 21 sprocket 21a sprocket hub 22 crankshaft 23 crank web 23a crank pin 24 crankshaft bearing 25 roller bearing 25a inner ring 25b outer ring 25c securing element 25d rolling body 26 crankshaft housing 27 oil collecting region 29 cylinder 30 connection rod bearing 31 connection rod 40 generator 41 receiving space 44 piston 45 inlet valve 46 outlet valve 47 first crankshaft 48 second crankshaft 49 balance shaft 50 first traction means 51 second traction means 52 flywheel mass element