Machine assembly comprising internal combustion engine

Abstract

The invention relates to a machine assembly (1) comprising an internal combustion engine (2) having at least one crankshaft (7) mounted in a crankcase (3) such that it can rotate about a crankshaft axis (7a), and at least one electric machine (11) comprising a rotor (14) rotatable about a rotor axis (14a), the rotor axis (14a) being arranged parallel to the crankshaft axis (7a), wherein the rotor (14) is drivingly connected to the crankshaft (7) via a gear stage (15), and wherein the gear stage (15) is arranged in a gear plane (epsilon) perpendicular to the rotor axis (14a) and the crankshaft axis (7a). According to the invention, in order to reduce wear and sound radiation, the housing (12) of the electric machine (11) is firmly connected to the crankcase (3) of the internal combustion engine (2) via a bridging element (22), the bridging element (22) being connected to the housing (12) of the electric machine (11) and to the crankcase (3) such that the distance between the rotor axis (14a) and the crankshaft axis (7a) is fixed by the bridging element (22).

Description

[0001] The present invention relates to a machine assembly comprising an internal combustion engine and at least one electric motor. The internal combustion engine has at least one crankshaft rotatably mounted in a crankcase about a crankshaft axis. The electric motor includes at least one rotor rotatable about a rotor axis, wherein the rotor axis is arranged parallel to the crankshaft axis. The rotor is drivingly connected to the crankshaft via a gear stage, and the gear stage is arranged in a gear plane perpendicular to the rotor axis and the crankshaft axis.

[0002] WO 2012 / 056275 A1 discloses a machine combination comprising an internal combustion engine having two counter-rotating crankshafts and a generator which is drivingly connected to one of the two crankshafts via a gear stage having an intermediate gear. The rotational axis of the generator is arranged parallel to the crankshaft and at a distance from the crankshaft. The internal combustion engine and the generator are arranged in a common housing.

[0003] US 9,843,238 B2 discloses a power generation device comprising an internal combustion engine and a generator, wherein the generator is connected to the internal combustion engine via an adapter. The generator and the crankshaft of the internal combustion engine are arranged on the same axis.

[0004] Especially in a light metal crankcase, when an electric motor is connected to a crankshaft via a gear stage, there is a problem with the dimensional accuracy of the flank clearance of the gears of the gear stage. This leads to increased wear and higher noise emissions.

[0005] The object of the present invention is to reduce wear and noise emissions in a machine assembly of the above type.

[0006] According to the present invention, this object is solved by the machine assembly described at the beginning in such a way that the housing of the electric motor is firmly connected to the crankcase of the internal combustion engine via a bridging member, wherein the bridging member is connected to the housing of the electric motor and the crankcase, preferably by a bolted connection, such that the distance between the rotor axis and the crankshaft axis is fixed by the bridging member.

[0007] Therefore, the distance between the rotor axis and the crankshaft axis, and thus the flank clearance of the meshing gears of the gear stage, is fixed to a predetermined dimension by the bridging member. By precisely defining the optimal flank clearance, wear and noise emissions are kept to a minimum.

[0008] Preferably, the crankshaft is mounted in the crankcase via at least one main bearing, and the fixed connection of the bridging member to the crankcase of the internal combustion engine is carried out in the region of the main bearing of the crankshaft. The bridging member can be directly or indirectly connected to the crankcase.

[0009] In an embodiment variant of the present invention, it is provided that the main bearing has an upper main bearing cap and a lower main bearing cap, wherein the lower main bearing cap can be connected to the upper main bearing cap, preferably by being tightly connected via main bearing bolts (bolt connection, threaded connection), and the bridging member is firmly connected to the upper main bearing cap of the crankcase, preferably via at least two first fastening means designed, for example, as bolts. It would be advantageous if the main bearing cap is designed as a separate component relative to the crankcase. This enables the upper main bearing cap to be formed of a material that can be designed to have a higher strength than the crankcase. In this embodiment variant, the bridging member is thus indirectly connected to the crankcase via the upper main bearing cap.

[0010] In an embodiment variant of the present invention, it is provided that the bridging member is firmly connected to the upper main bearing cap via at least two first fastening means, wherein preferably at least one of the first fastening means is arranged to extend parallel to at least one main bearing bolt of the internal combustion engine.

[0011] Advantageously, the housing of the electric machine is connected to the bridging member via second fastening means, wherein preferably at least three or four second fastening means are provided, and these second fastening means are particularly preferably positioned around the rotor axis.

[0012] In another variant of the present invention, one end of the rotor protruding from the housing of the electric machine passes through a groove defined (bounded) by a wall region in the crankcase, wherein the housing is arranged on a first side of the wall region, the bridging member is arranged on a second side of the wall region opposite to the first side, and the housing is pressed against the wall region of the crankcase in a region at least partially concentrically surrounding the rotor axis by means of the second fastening means, wherein preferably at least one external sealing element is provided between the wall region and the housing, and the at least one external sealing element is installed in a corresponding groove in the housing or the wall region. It would be particularly advantageous if at least the second fastening means are arranged parallel to the rotor axis. This enables the electric machine to be firmly connected to the crankcase with an optimal power flow.

[0013] In a further embodiment of the present invention, it is provided that the gear stage has at least one rotor gear that is non-rotatably connected to the rotor and at least one crankshaft gear that is operatively connected to the rotor gear and non-rotatably connected to the crankshaft, wherein the gear stage preferably has at least one intermediate gear that meshes with the rotor gear and / or the crankshaft gear. It would be advantageous if the intermediate gear is rotatably mounted on an intermediate gear support, and the intermediate gear support is fastened to the bridging member, preferably by being tightened to the bridging member via at least four or five third bolts. The bridging member and / or the intermediate gear support are each formed by plate-like elements arranged substantially parallel to the gear plane, and the plate-like elements are preferably rigid.

[0014] The bridging member and / or the intermediate gear carrier are rigid, i.e., hard and inelastic. The stiffness of the bridging member and / or the intermediate gear carrier is preferably higher than the stiffness of the crankcase, wherein the stiffness of the bridging member and / or the intermediate gear carrier is preferably higher than the stiffness of the upper part of the main bearing cap. The stiffness of the technical subject is essentially determined by the geometry, such as the bending moment resistance about the axis, and the material, such as the modulus of elasticity or the shear modulus.

[0015] Advantageously, the bridging member and / or the intermediate gear carrier each have a modulus of elasticity higher than the modulus of elasticity of the crankcase, wherein the modulus of elasticity of the bridging member and / or the intermediate gear carrier is preferably higher than the modulus of elasticity of the upper part of the main bearing cap. The bridging member and / or the intermediate gear carrier and / or the upper part of the main bearing cap are preferably made of steel. The crankcase can be made of light metal, such as aluminum alloy.

[0016] As an alternative or in addition, it can be provided that the bridging member and / or the intermediate gear carrier have a sectional modulus about the rotor axis or about the crankshaft axis that is higher than the sectional modulus of the corresponding wall region of the crankcase between the rotor axis and the crankshaft axis.

[0017] The invention will be explained in more detail with reference to the non-limiting exemplary embodiments shown in the accompanying drawings, wherein:

[0018] Figure 1 An axonometric front view of a machine assembly according to the invention is shown;

[0019] Figure 2 An axonometric rear view of the machine assembly is shown;

[0020] Figure 3 An axonometric front view of the machine assembly with the covering section removed is shown;

[0021] Figure 4 A front view of the machine assembly after the covering section has been removed is shown;

[0022] Figure 5 A front view of the machine assembly with the intermediate gear carrier removed is shown;

[0023] Figure 6 An axonometric view of the machine assembly as seen from below is shown;

[0024] Figure 7 An axonometric view of the details of the machine assembly with the intermediate gear removed is shown;

[0025] Figure 8 Shows in Figure 4 Details of the machine assembly in a section taken along line VIII-VIII in

[0026] Figure 9 Shows in Figure 4Details of the machine components in the cross-section taken along the IX-IX line;

[0027] Figure 10 in Figure 9 the axonometric view of the cross-sectional view shows the details of the machine components;

[0028] Figure 11 The details of the machine components are shown in axonometric view with the electric motor removed;

[0029] Figure 12 The machine components are shown in another axonometric rear view;

[0030] Figure 13 The front side of the bridging member of the machine components is shown in axonometric view; and

[0031] Figure 14 The rear side of the bridging member is shown in another axonometric view.

[0032] Figures 1 to 12 The machine components 1 are shown, which include an internal combustion engine 2 and an electric motor 11, and the electric motor 11 is specifically designed as a generator.

[0033] The internal combustion engine 2 has a crankcase 3 made of light metal with two cylinders 4, and reciprocating pistons 5 are guided in the cylinders 4. A cylinder head 3a is arranged on the crankcase 3 (see Figure 2 ). Except Figure 2 outside, the cylinder head 3a is not shown in other figures. A machine support 1a is arranged on the side of the crankcase 3. The bottom of the crankcase 3 is closed by an oil pan 66 (see Figures 3 to 5 ).

[0034] In the crankcase 3, a first crankshaft 7 and a second crankshaft 8 are rotatably mounted via main bearings 6 around their respective crankshaft axes 7a, 8a. Each main bearing 6 has an upper main bearing bracket 6a and a lower main bearing bracket 6b, which are interconnected by, for example, two main bearing bolts 6c. In the shown exemplary embodiment, the upper main bearing bracket 6a is designed as a separate component relative to the crankcase 3 and is made of steel, for example.

[0035] Each reciprocating piston 5 acts as a driving member on the relevant crankshafts 7, 8. The two crankshafts 7, 8 are arranged parallel to each other, and they are in turn driven and connected in opposite directions via crankshaft gears 9, 10 attached to them on the same axis.

[0036] The electric motor 11 formed by the generator is connected to the power electronics 21. The electric motor 11 has a housing 12, in which a stator 13 and a rotor 14 rotatable around a rotor axis 14a are arranged, and the rotor axis 14a is arranged parallel to the crankshaft axes 7a, 8a (see Figure 12 ).

[0037] The rotor 14 of the electric machine 11 is drivingly connected to the first crankshaft 7 via a gear stage 15 (see Figure 5 ). As can be seen in Figure 1 , during normal use, the gear stage 15 is covered by the housing cover 19 at the front of the machine assembly 1.

[0038] The gear stage 15 consists of a rotor gear 16 that is non-rotatably connected (anti-torsionally connected) to the rotor 14, an intermediate gear 17 that meshes with the rotor gear 16, and a first crankshaft gear 9 that meshes with the intermediate gear 17. The rotor gear 16 is rotatably connected to the rotor 14 via a central bolt 18. The flywheel 10a is non-rotatably connected to the second crankshaft gear 10 or the second crankshaft 8 (see Figure 3 and Figure 4 ).

[0039] The gear stage 15 is arranged in a gear plane ε that is normal to the rotor axis 14a and the crankshaft axes 7a, 8a. In the exemplary embodiment shown, the electric machine 11 and the crankcase 3 are arranged on the same side of the gear plane ε.

[0040] In order to keep the flank clearances of the gears of the gear stage 15, in particular the teeth of the first crankshaft gear 9, the intermediate gear 17, and the rotor gear 16, as small as possible, a bridging member 22 is provided on the machine assembly. The bridging member 22 establishes a firm (fixed) connection between the housing 12 of the electric machine 11 and the crankcase 3 of the internal combustion engine 2. The bridging member 22 is fixedly connected to the crankcase 3, in particular in the region of the main bearing 6 of the first crankshaft 7, and the housing 12 of the electric machine 11 is connected to the bridging member 22 such that the spacing between the rotor axis 14a and the crankshaft axis 7a of the first crankshaft 7 is fixedly and unchangeably fixed by the bridging member 22.

[0041] Figure 13 The front side of the bridging member 22 is shown, which faces away from the crankcase 3 in the assembled state; while Figure 14 the rear side of the bridging member 22 is shown, which is oriented towards the crankcase 3 or the electric machine 11. The bridging member 22 is substantially plate-shaped, and when the bridging member 22 is installed, the plate plane is oriented parallel to the gear plane ε. The bridging member 22 is designed as a rigid element. In Figure 13 , a receiving portion 27 for fastening means is shown that concentrically surrounds the rotor gear recess 38, where these fastening means are the second fastening means 26, preferably in the form of bolts, in order to connect the electric machine 11 to the bridging member 22 via the housing 12 of the electric machine 11. The receiving portion 27 is designed as an unmachined hole, and then the second fastening means 26 are fastened or screwed into corresponding openings in the housing 12, which openings are designed, for example, to have threads.

[0042] In addition, a total of five drilling bushings 35 are shown, via which an intermediate gear carrier 33, which will be further explained below, can be fastened to the bridging member 22 using a third fastening means 34. If bolts are used as the third fastening means 34, the drilling bushings 35 can be provided with internal threads to enable screwing.

[0043] A support point 37 for the intermediate gear 17 is provided centrally on the bridging member 22, the support point 37 having a threaded hole 36 for receiving a bolt through which the intermediate gear 17 can be mounted.

[0044] Figure 14 Two fastening lugs 24 are clearly shown, by means of which the bridging member 22 can be connected directly or indirectly to the crankcase 3. For this purpose, a first hole 25 is provided in the fastening lugs 24 for receiving a fastening means, such as a bolt. The fastening lugs 24 are inclined by approximately 90° relative to the gear plane ε.

[0045] As Figure 7 shown, the bridging member 22 is connected to the crankcase 3 of the internal combustion engine 2. This fixed connection takes place in the region of the main bearing 6 of the first crankshaft 7. In the exemplary embodiment shown, the upper part 6a of the main bearing cap of the main bearing 6 is designed as a separate part relative to the crankcase 3, which is made of steel, for example, and is fixedly connected to the crankcase 3. The bridging member 22 is firmly connected to the upper part 6a of the main bearing cap and is thus indirectly connected to the crankcase 3. In a variant not shown, the upper part 6a of the main bearing cap is integrally formed (made in one piece) with the crankcase 3, such that when the bridging member 22 is mounted on the upper part 6a of the main bearing cap it is directly connected to the crankcase 3.

[0046] The bridging member 22 is connected to the upper part 6a of the main bearing cap and thus to the crankcase 3 via only two first fastening means 23, which are designed as bolts and are screwed (threaded) into the crankcase 3 through the first holes 25 provided in the fastening lugs 24 of the bridging member 22. In the exemplary embodiment shown, the first fastening means 23 are arranged parallel to the main bearing bolts 6c and / or the cylinder axis 4a of the cylinders 4 of the internal combustion engine 2. In particular, the fastening means 23 are oriented orthogonally to the first crankshaft axis 7a and the rotor axis 14a ( Figure 12 ).

[0047] On the other hand, the bridging member 22 is firmly connected to the electric machine 11. For this purpose, a second fastening means 26, in the form of a bolt here, is guided through a receiving part 27 in the bridging member 22 and is screwed into a corresponding threaded hole in the housing 12 of the electric machine 11. The second fastening means 26 is arranged parallel to the rotor axis 14a here. During installation, the rotor 14 on which the rotor gear 16 is already mounted projects through a rotor gear recess 38 in the bridging member 22.

[0048] In particular Figure 11 it can be seen that in the crankcase 3 a recess 39 delimited by a wall region 30 is provided, which, when the bridging member 22 is installed, substantially corresponds to the rotor gear recess 38 in the bridging member 22.

[0049] After the electric machine 11 is screwed onto the bridging member 22, the rotor 14 or the end of the rotor 14 protruding from the housing 12 of the electric machine 11 projects through the recess 39 in the crankcase 3 delimited by the wall region 30 and the rotor gear recess 38 in the bridging member 22, so that the rotor gear 16 can be installed and operated properly. The housing 12 is arranged on a first side of the wall region 30, and the bridging member 22 is arranged on a second side of the wall region 30 opposite the first side.

[0050] The housing 12 is pressed against the wall region 30 of the crankcase 3 by means of a second fastening device 26 in a region at least partially concentrically surrounding the rotor axis 14a, thereby producing a sealing effect. For this purpose, at least one external sealing element 67 ( Figure 8 ) is provided in a corresponding recess installed in the housing 12 between the wall region 30 and the housing 12. In addition, an internal sealing element 68 is provided in the region close to the rotor 14, which is arranged between the rotor 14 and the housing 12.

[0051] In addition to being attached to the bridging member 22, the electric machine 11 is also directly connected to the crankcase 3. For this purpose, a bushing 32 ( Figure 11 ) is provided in the region of the rear side 31 of the crankcase 3 facing away from the gear plane ε, via which the housing 12 can be screwed (threaded) to the crankcase 3 by means of two further fastening devices designed as fastening bolts 29 ( Figure 12 ).

[0052] In the broadest sense, the bridging member 22 is also used to accommodate the intermediate gear 17 of the gear stage 15, which is rotatably mounted on a separate, flat, substantially plate-shaped intermediate gear carrier 33 via a sliding bearing lubricated with pressurized oil. As can be seen in particular from Figure 9 the sliding bearing (not shown) represents a part of the intermediate gear carrier 33 and sits on a bearing seat 37, which is a part of the bridging member 22 (see Figure 13 ). The intermediate gear 17 is fastened by means of a threaded connection 36a in a threaded hole 36 formed in the bearing seat 37. Thus, the intermediate gear 17 is only attached to the bridging member 22 or the intermediate gear carrier 33, and there is no direct connection to the crankcase 3 or the housing 12 of the electric machine 11.

[0053] The intermediate gear carrier 33 is fastened to the bridging member 22 via a third fastening means 34, where the third fastening means is designed as a bolt. For this purpose, the above-described drilled bushings 35 are provided on the bridging member 22, and these drilled bushings 35 are designed with internal threads for receiving the third fastening means 34. Thus, the intermediate gear carrier 33 is only connected to the bridging member 22, and there is no direct connection to the crankcase 3 or the housing 12 of the electric machine 11.

[0054] In order to reduce wear and noise emissions, the bridging member 22 and / or the intermediate gear carrier 33 are made of a material having a higher modulus of elasticity than the crankcase 3, preferably also higher than the upper part 6a of the main bearing cover. In addition, the sectional modulus of the bridging member 22 and / or the intermediate gear carrier 33 about the rotor axis 14a or about the first crankshaft axis 7a can be higher than the sectional modulus of the corresponding wall region 30 of the crankcase 3 between the rotor axis 14a and the first crankshaft axis 7a.

[0055] In the exemplary embodiment shown, the bridging member 22 is made of a material that is stronger than the crankcase 3, such as steel. In this exemplary embodiment, the intermediate gear carrier 33 is also formed by steel plates arranged substantially parallel to the gear plane ε.

[0056] The rigid bridging member 22 keeps the flank clearance of the gear stage 15 as small as possible, on the one hand to minimize noise emissions and on the other hand to minimize wear of the gears of the gear stage 15. All gears required for the gear stage 15 are mounted in steel or machined with a universal clamping device to keep the center distance tolerance as small as possible.

Claims

1. A machine component (1), comprising an internal combustion engine (2) having at least one crankshaft (7) and at least one electric motor (11), wherein the crankshaft (7) is rotatably mounted in a crankcase (3) about a crankshaft axis (7a), and the electric motor (11) comprises at least one rotor (14) rotatable about a rotor axis (14a), wherein the rotor axis (14a) is arranged parallel to the crankshaft axis (7a), wherein the rotor (14) is drivingly connected to the crankshaft (7) via a gear stage (15), and wherein the gear stage (15) is arranged in a gear plane (ε) arranged perpendicular to the rotor axis (14a) and the crankshaft axis (7a), characterized in that, The housing (12) of the electric machine (11) is firmly connected to the crankcase (3) of the internal combustion engine (2) via a bridging member (22), wherein the bridging member (22) is connected to the housing (12) of the electric machine (11) and the crankcase (3), preferably by a bolted connection, such that the spacing between the rotor axis (14a) and the crankshaft axis (7a) is fixed by the bridging member (22).

2. The machine component (1) according to claim 1, characterized in that, The crankshaft (7) is mounted in the crankcase (3) via at least one main bearing (6), and the bridging member (22) is firmly connected to the crankcase (3) of the internal combustion engine (2) in the region of the main bearing (6).

3. The machine component (1) according to claim 2, characterized in that, The main bearing (6) has an upper main bearing cap (6a) and a lower main bearing cap (6b), wherein the lower main bearing cap (6b) can be connected to the upper main bearing cap (6a), preferably by threaded connection via main bearing bolts (6c), and the bridging member (22) is firmly connected to the upper main bearing cap (6a) of the main bearing (6).

4. The machine component (1) according to claim 2 or 3, characterized in that, The bridging member (22) is firmly connected to the upper main bearing cap (6a) via at least two first fastening means (23), wherein preferably at least one first fastening means (23) is arranged to extend parallel to at least one main bearing bolt (6c) of the main bearing (6) of the internal combustion engine (2).

5. The machine component (1) according to any one of claims 1 to 4, characterized in that, The housing (12) of the electric machine (11) is connected to the bridging member (22) via second fastening means (26), wherein preferably at least three or four of the second fastening means (26) are provided, and particularly preferably the second fastening means (26) are positioned around the rotor axis (14a).

6. The machine component (1) according to claim 5, characterized in that, One end of the rotor (14) protruding from the housing (12) of the electric machine (11) passes through a recess (39) defined by a wall region (30) in the crankcase (3), wherein the housing (12) is arranged on a first side of the wall region (30), the bridging member (22) is arranged on a second side of the wall region (30) opposite to the first side, and the housing (12) is pressed against the wall region (30) of the crankcase in a region at least partially concentrically surrounding the rotor axis (14a) by means of the second fastening means (26), wherein preferably at least one external sealing element (67) is provided between the wall region (30) and the housing (12), and the at least one external sealing element (67) is installed in a corresponding recess in the housing (11) or the wall region (30).

7. The machine component (1) according to any one of claims 1 to 6, characterized in that, The gear stage (15) has at least one rotor gear (16) non-rotatably connected to the rotor (14) and at least one crankshaft gear (9) operatively connected to the rotor gear (16) and non-rotatably connected to the crankshaft (7), wherein the gear stage (15) preferably has at least one intermediate gear (17) meshing with the rotor gear (16) and / or the crankshaft gear (9).

8. The machine component (1) according to claim 7, characterized in that, The intermediate gear (17) is rotatably mounted on an intermediate gear carrier (33), which is fastened to the bridging member (22), preferably via a third fastening means (34), particularly preferably the third fastening means being designed as a bolt.

9. The machine component (1) according to any one of claims 1 to 8, characterized in that, The bridging member (22) and / or the intermediate gear carrier (33) are each formed by a plate-shaped element arranged substantially parallel to the gear plane (ε).

10. The machine component (1) according to any one of claims 1 to 9, characterized in that, The bridging member (22) and / or the intermediate gear carrier (33) have a higher modulus of elasticity than the crankcase (3), wherein the bridging member (22) and / or the intermediate gear carrier (33) preferably have a higher modulus of elasticity than the upper part of the main bearing cap (6a).

11. The machine component (1) according to any one of claims 1 to 10, characterized in that, The bridging member (22) and / or the intermediate gear carrier (33) have a higher section modulus about the rotor axis (14a) or about the crankshaft axis (7a) than the corresponding wall region (30) of the crankcase (3), in particular higher than the wall region between the rotor axis (14a) and the crankshaft axis (7a).

12. The machine component (1) according to any one of claims 1 to 11, characterized in that, The bridging member (22) and / or the intermediate gear carrier (33) and / or the upper part of the main bearing cap (6a) are made of steel.

13. The machine component (1) according to any one of claims 1 to 12, characterized in that, The crankcase (3) is made of light metal.

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