MACHINE ARRANGEMENT WITH AN INTERNAL ENGINE

Description

[0001] The invention relates to a machine arrangement comprising an internal combustion engine with at least one crankshaft rotatably mounted in a crankcase about a crankshaft axis and at least one electric machine with at least one rotor rotatable about a rotor axis, wherein the rotor axis is arranged parallel to the crankshaft axis, wherein the rotor is connected to the crankshaft via a gear stage, and wherein the gear stage is arranged in a gear plane normal to the rotor axis and the crankshaft axis, wherein a housing of the electric machine is rigidly connected to the crankcase of the internal combustion engine via a bridge section, wherein the bridge section is connected to the housing of the electric machine and to the crankcase, preferably by screws, and wherein the distance between the rotor axis and the crankshaft axis is fixed by the bridge section.and wherein the crankshaft is supported in the crankcase via at least one main bearing and the bridge section is rigidly connected to the crankcase of the internal combustion engine in the area of ​​the main bearing.

[0002] WO 2012 / 056275 A1 discloses a machine combination comprising an internal combustion engine with two counter-rotating crankshafts and a generator which is driven via a gear stage and an intermediate gear to one of the two crankshafts. The axis of rotation of the generator is parallel to the crankshafts and spaced apart from them. The internal combustion engine and the generator are arranged in a common housing.

[0003] US Patent 9,843,238 B2 discloses a power generating unit comprising an internal combustion engine and a generator, wherein the generator is connected to the internal combustion engine via an adapter. The generator is arranged coaxially with the crankshaft of the internal combustion engine.

[0004] Particularly in crankcases made of light alloy, where the electric motor is connected to the crankshaft via a gear stage, the problem of dimensional accuracy of the backlash of the gears in the gear stage arises. This leads to increased wear and higher noise emissions.

[0005] DE 10 2007 001 840 A1 discloses a hybrid drive for a motor vehicle comprising an internal combustion engine, a transmission downstream of it and an electric motor associated with the transmission, which is mounted on the transmission via a support arm.

[0006] US 10,532,647 B2 describes a hybrid vehicle with an internal combustion engine and a motor-generator, which is connected to the internal combustion engine via transmission housings.

[0007] DE 10 2013 018 057 A1 discloses a hybrid drive for a rail vehicle, comprising a diesel engine and two electric motors. The drive has a housing element with a central housing body containing a bearing for supporting a shaft of the drive's drive train. The housing element has a flange extending radially outwards from the circumference of the housing body. A bracket is formed in the flange for holding and securing an electric motor.

[0008] EP 2 574 810 B4 describes a drive unit with an electric machine and an internal combustion engine, wherein the housing of the electric machine is rigidly connected to the crankcase of the internal combustion engine via a bridge part.

[0009] The object of the invention is to reduce wear and noise emission in a machine arrangement of the type mentioned.

[0010] This problem is solved according to the invention by a machine arrangement mentioned above in that the main bearing has a main bearing bracket upper part and a main bearing bracket lower part, wherein the main bearing bracket lower part can be connected to the main bearing bracket upper part and the bridge part is firmly connected to the main bearing bracket upper part of the main bearing.

[0011] The distance between the rotor axis and the crankshaft axis – and thus the backlash of the meshing gears in the gear stage – is therefore fixed to a predefined dimension by the bridge section. By precisely defining the optimal backlash, wear and noise emissions are minimized.

[0012] The connection between the bridge section and the crankcase can be direct or indirect.

[0013] In one embodiment of the invention, the lower part of the main bearing bracket is screwed to the upper part of the main bearing bracket via main bearing bolts, and in particular, the bridge part is firmly connected to the upper part of the main bearing bracket of the crankcase via at least two first fastening means, which are, for example, designed as bolts. It is advantageous if the main bearing bracket is designed as a separate part with respect to the crankcase. This makes it possible to manufacture the upper part of the main bearing bracket from a material with higher strength than the crankcase. In this embodiment, the bridge part is thus indirectly connected to the crankcase via the upper part of the main bearing bracket.

[0014] One embodiment of the invention provides that the bridge part is firmly connected to the main bearing bracket upper part by means of at least two first fastening means, wherein preferably at least one first fastening means is arranged parallel to at least one main bearing bolt of the internal combustion engine.

[0015] Advantageously, the housing of the electric machine is connected to the bridge part via second fastening means, preferably at least three or four second fastening means being provided, which are particularly preferably positioned around the rotor axis.

[0016] In a further embodiment of the invention, an end of the rotor protruding from the housing of the electric machine extends through a recess in the crankcase bounded by a wall section. The housing is arranged on a first side and the bridge section on a second side of the wall section opposite the first side. The housing is pressed against the wall section of the crankcase by means of the second fastening means in a region that at least partially surrounds the rotor axis concentrically. Preferably, at least one outer sealing element is provided between the wall section and the housing, mounted in a corresponding recess in the housing or the wall section. It is particularly advantageous if at least one second fastening means is arranged parallel to the rotor axis. This enables a secure connection of the electric machine to the crankcase with optimal force transmission.

[0017] In a further embodiment of the invention, the gear stage comprises at least one rotor gear non-rotatably connected to the rotor and at least one crankshaft gear operatively connected to the rotor gear and non-rotatably connected to the crankshaft, wherein the gear stage preferably comprises at least one intermediate gear which meshes with the rotor gear and / or the crankshaft gear. It is advantageous if the intermediate gear is rotatably mounted on an intermediate gear carrier, which intermediate gear carrier is attached to the bridge part, preferably by means of at least four or five screws. The bridge part and / or the intermediate gear carrier is / are each formed by a plate-shaped – preferably rigid – element arranged substantially parallel to the gear plane.

[0018] The bridge section and / or the intermediate gear carrier is / are rigid, i.e., stiff and inelastic. The bridge section and / or the intermediate gear carrier preferably have a higher stiffness than the crankcase, with the bridge section and / or the intermediate gear carrier preferably having a higher stiffness than the upper part of the main bearing bracket. The stiffness of a technical body is essentially defined by its geometry—for example, the section modulus about an axis—and the material—for example, the modulus of elasticity or the shear modulus.

[0019] Advantageously, the bridge section and / or the intermediate gear carrier each have a higher modulus of elasticity than the crankcase, with the bridge section and / or the intermediate gear carrier preferably having a higher modulus of elasticity than the upper main bearing bracket. The bridge section and / or the intermediate gear carrier and / or the upper main bearing bracket are preferably made of steel. The crankcase can be made of a light metal, for example, an aluminum alloy.

[0020] Alternatively or additionally, it may be provided that the bridge part and / or the intermediate gear carrier has a higher resistance moment around the rotor axis or around the crankshaft axis than a corresponding wall area of ​​the crankcase between the rotor axis and the crankshaft axis.

[0021] The invention is explained in more detail below with reference to a non-limiting embodiment illustrated in the figures. These show: Fig. 1 an axonometric front view of a machine arrangement according to the invention; Fig. 2 the machine arrangement in an axonometric rear view; Fig. 3 the machine arrangement with the cover part removed in an axonometric front view; Fig. 4 the machine arrangement with the cover part removed in a front view; Fig. 5 the machine arrangement with the intermediate gear carrier removed in a front view; Fig. 6 the machine arrangement in an axonometric view from below; Fig. 7 a detail of the machine arrangement with the intermediate gear removed in an axonometric view; Fig. 8 a detail of the machine arrangement in a section along line VIII-VIII in Fig. 4 Fig. 9 shows a detail of the machine arrangement in a section along line IX-IX. Fig. 4 Fig. 10 shows a detail of the machine arrangement in an axonometric representation of the sectional view from Fig. 9 Fig. 11 shows a detail of the machine arrangement in an axonometric view with the electrical machine removed; Fig. 12 shows the machine arrangement in a further axonometric rear view; Fig. 13 shows a front view of the bridge part of the machine arrangement in an axonometric view; and Fig. 14 shows a rear view of the bridge part in a further axonometric view.

[0022] The Fig. 1 bis Fig. 12 show a machine arrangement 1 with an internal combustion engine 2 and an electric machine 11, which is designed in particular as a generator.

[0023] The internal combustion engine 2 has a crankcase 3 made of light alloy with two cylinders 4 in which reciprocating pistons 5 are guided. A cylinder head 3a is arranged on the crankcase 3 (see Fig. 2 ). The cylinder head 3a is shown in all figures except Fig. 2 not shown. A machine support 1a is arranged laterally on the crankcase 3. The crankcase 3 is closed off at the bottom by an oil pan 66 (see Fig. 3 bis Fig. 5 ).

[0024] In the crankcase 3, a first crankshaft 7 and a second crankshaft 8 are rotatably mounted about their respective crankshaft axes 7a, 8a via main bearings 6. Each main bearing 6 has an upper main bearing bracket 6a and a lower main bearing bracket 6b, which are connected to each other, for example by two main bearing bolts 6c. In the illustrated embodiment, the upper main bearing bracket 6a is designed as a separate component with respect to the crankcase 3 and is made, for example, of steel.

[0025] Each piston 5 drives a corresponding crankshaft 7, 8. The two crankshafts 7, 8 are arranged parallel to each other and are in turn connected in opposite directions via a crankshaft gear 9, 10 attached to them coaxially.

[0026] The electric machine 11 formed by a generator is connected to power electronics 21. The electric machine 11 has a housing 12 in which a stator 13 and a rotor 14 rotatable about a rotor axis 14a are arranged, the rotor axis 14a being arranged parallel to the crankshaft axes 7a, 8a (see Fig. 12 ).

[0027] The rotor 14 of the electric machine 11 is connected to the first crankshaft 7 via a gear stage 15 (see Fig. 5 ). In Fig. 1 It can be seen that, when used as intended, the gear stage 15 is covered by a housing cover 19 at the front of the machine assembly 1. The gear stage 15 consists of a rotor gear 16, which is non-rotatably connected to the rotor 14, an intermediate gear 17 meshing with the rotor gear 16, and the first crankshaft gear 9 meshing with the intermediate gear 17. The rotor gear 16 is non-rotatably connected to the rotor 14 by a central screw 18. A flywheel 10a is non-rotatably connected to the second crankshaft gear 10 or the second crankshaft 8 (see Fig. 3 und Fig. 4 ).

[0028] The gear stage 15 is arranged in a gear plane ε normal to the rotor axis 14a and to the crankshaft axes 7a, 8a. In the illustrated embodiment, the electric machine 11 and the crankcase 3 are arranged on the same side of the gear plane ε.

[0029] To minimize the backlash of the gears in gear stage 15, particularly the first crankshaft gear 9, the intermediate gear 17, and the rotor gear 16, a bridge section 22 is provided on the machine assembly. The bridge section 22 establishes a rigid connection between the housing 12 of the electric machine 11 and the crankcase 3 of the internal combustion engine 2. The bridge section 22 is rigidly connected to the upper main bearing bracket 6a, and the housing 12 of the electric machine 11 is connected to the bridge section 22, so that the distance between the rotor axis 14a and the crankshaft axis 7a of the first crankshaft 7 is fixed by the bridge section 22. Fig. 13 shows a front side of the bridge part 22, which in the assembled state is oriented away from the crankcase 3, while Fig. 14 Figure 22 shows a rear side of the bridge section 22, which is oriented towards the crankcase 3 or the electric machine 11. The bridge section 22 is essentially plate-shaped, with the plate plane being oriented parallel to the gear plane ε when the bridge section 22 is mounted. The bridge section 22 is designed as a rigid element. Fig. 13 Each of the following is shown concentrically arranged around a rotor gear recess 38: Receptacles 27 for fastening means, wherein the second fastening means 26 – preferably in the form of screws – are used to connect the electric machine 11 to the bridge part 22 via its housing 12. The receptacles 27 are designed as unmachined holes, and the second fastening means 26 are then fastened or screwed into corresponding openings in the housing 12, which are, for example, threaded.

[0030] Furthermore, a total of five bore bosses 35 are shown, via which an intermediate gear carrier 33, explained below, can be attached to the bridge part 22 using third fastening means 34. If screws are used as the third fastening means 34, the bore bosses 35 can be provided with an internal thread to allow screwing.

[0031] A bearing point 37 for the intermediate gear 17 is provided centrally on the bridge part 22, which has a threaded bore 36 for receiving a screw with which the intermediate gear 17 can be mounted.

[0032] In Fig. 14 Two mounting tabs 24 are clearly visible, with which the bridge section 22 can be directly or indirectly firmly connected to the crankcase 3. For this purpose, the mounting tabs 24 have initial bores 25 for receiving fasteners – for example, screws. The mounting tabs 24 are angled at approximately 90° with respect to the gear plane ε.

[0033] As in Fig. 7 As shown, the bridge section 22 is connected to the crankcase 3 of the internal combustion engine 2. This fixed connection is made in the area of ​​a main bearing 6 of the first crankshaft 7. In the illustrated embodiment, the upper part of the main bearing 6a is designed as a separate component with respect to the crankcase 3, is made, for example, of steel, and is fixedly connected to the crankcase 3. The bridge section 22 is fixedly connected to the upper part of the main bearing 6a and thus indirectly to the crankcase 3. In a variant not shown, the upper part of the main bearing 6a is formed integrally with the crankcase 3, so that the bridge section 22 is directly connected to the crankcase 3 when mounted on the upper part of the main bearing 6a.

[0034] The connection of the bridge section 22 to the main bearing bracket upper section 6a, and thus to the crankcase 3, is effected by only two first fastening means 23, which are designed as screws and are screwed into the crankcase 3 through the first bores 25 provided therein on the mounting lugs 24 of the bridge section 22. In the illustrated embodiment, the first fastening means 23 are arranged parallel to the main bearing bolts 6c and / or to the cylinder axes 4a of the cylinders 4 of the internal combustion engine 2. In particular, the fastening means 23 are oriented perpendicular to the first crankshaft axis 7a and to the rotor axis 14a ( Fig. 12 ).

[0035] On the other hand, the bridge section 22 is rigidly connected to the electric machine 11. For this purpose, second fastening elements 26 – here in the form of screws – are guided through the receptacles 27 in the bridge section 22 and screwed into corresponding threaded holes in the housing 12 of the electric machine 11. The second fastening elements 26 are arranged here parallel to the rotor axis 14a. In the assembled state, the rotor 14 with the mounted rotor gear 16 protrudes through the rotor gear recess 38 in the bridge section 22.

[0036] Especially in Fig. 11 It can be seen that a recess 39, limited by a wall area 30, is provided in the crankcase 3, which in the assembled state of the bridge part 22 essentially corresponds to the rotor gear recess 38 carried out in the bridge part 22.

[0037] After the electric machine 11 is bolted to the bridge section 22, the rotor 14, or rather an end of the rotor 14 protruding from the housing 12 of the electric machine 11, projects through the recess 39 in the crankcase 3, which is bounded by the wall section 30, and through the rotor gear recess 38 in the bridge section 22, so that the rotor gear 16 can be mounted and operated correctly. The housing 12 is positioned on one side and the bridge section 22 on the other side of the wall section 30, opposite the first side.

[0038] The housing 12 is pressed against the wall section 30 of the crankcase 3 by means of the second fastening means 26 in an area that at least partially surrounds the rotor axis 14a concentrically, thus creating a sealing effect. For this purpose, at least one outer sealing element 67, mounted in a corresponding recess in the housing 12, is provided between the wall section 30 and the housing 12. Fig. 8 Additionally, an inner sealing element 68 is provided in an area near the rotor 14, arranged between the rotor 14 and the housing 12.

[0039] In addition to being attached to the bridge section 22, the electric machine 11 is also directly connected to the crankcase 3. For this purpose, bosses 32 are provided in the area of ​​the rear side 31 of the crankcase 3 facing away from the gear plane ε ( Fig. 11 ), via which the housing 12 can be screwed to the crankcase 3 by means of two further fastening means designed as fastening screws 29 ( Fig. 12 ).

[0040] Furthermore, the bridge section 22 also serves, in the broadest sense, to accommodate the intermediate gear 17 of the gear stage 15, which is rotatably mounted on a separate flat, essentially plate-shaped intermediate gear carrier 33 via a hydraulically lubricated sliding bearing. As shown in particular in Fig. 9 As can be seen, the sliding bearing (without reference numeral) forms part of the intermediate gear carrier 33 and sits on a bearing receptacle 37, which is part of the bridge part 22 (see Fig. 13 The intermediate gear 17 is fastened by a screw 36a in a threaded bore 36, which is provided in the bearing receptacle 37. The intermediate gear 17 is therefore only fastened to the bridge part 22 or to the intermediate gear carrier 33, and there is no direct connection to the crankcase 3 or to the housing 12 of the electric machine 11.

[0041] The intermediate gear carrier 33 is attached to the bridge part 22 by means of third fastening elements 34, which are implemented here as screws. For this purpose, the bridge part 22 has the bore bosses 35 described above, which are designed with an internal thread to receive the third fastening elements 34. The intermediate gear carrier 33 is therefore only connected to the bridge part 22 and there is no direct connection to the crankcase 3 or to the housing 12 of the electric machine 11.

[0042] To reduce wear and noise emission, the bridge part 22 and / or the intermediate gear carrier 33 are made of a material with a higher modulus of elasticity than the crankcase 3, preferably also of a material with a higher modulus of elasticity than the main bearing bracket upper part 6a. Furthermore, the bridge part 22 and / or the intermediate gear carrier 33 can have a higher section modulus about the rotor axis 14a or about the first crankshaft axis 7a than a corresponding wall area 30 of the crankcase 3 between the rotor axis 14a and the first crankshaft axis 7a.

[0043] In the illustrated embodiment, the bridge part 22 is made of a stronger material than the crankcase 3, for example, steel. In this embodiment, the intermediate gear carrier 33 is also formed by a steel plate arranged substantially parallel to the gear plane ε.

[0044] The rigid bridge section 22 allows the backlash of the gear stage 15 to be kept as low as possible, thus minimizing both noise emission and wear on the gears of the gear stage 15. All gears required for the gear stage 15 are mounted in steel or machined in a single setup to keep center distance tolerances as small as possible.

Claims

1. Machine arrangement (1) having an internal combustion engine (2) with at least one crankshaft (7) rotatably mounted in a crankcase (3) about a crankshaft axis (7a) and at least one electric machine (11) with 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 drive-connected to the crankshaft (7) via a gear stage (15), and wherein the gear stage (15) is arranged in a gear plane (ε) arranged normal to the rotor axis (14a) and the crankshaft axis (7a), wherein a housing (12) of the electric machine (11) is firmly connected to the crankcase (3) of the internal combustion engine (2) via a bridge part (22), wherein the bridge part (22) is connected, preferably bolted, to the housing (12) of the electric machine (11) and to the crankcase (3), wherein the distance between the rotor axis (14a) and the crankshaft axis (7a) is fixed by the bridge part (22), and wherein the crankshaft (7) is mounted in the crankcase (3) via at least one main bearing (6) and the bridge part (22) is firmly connected to the crankcase (3) of the internal combustion engine (2) in the area of the main bearing (6), characterised in that the main bearing (6) has a main bearing bracket upper part (6a) and a main bearing bracket lower part (6b), wherein the main bearing bracket lower part (6b) can be connected to the main bearing bracket upper part (6a) and the bridge part (22) is firmly connected to the main bearing bracket upper part (6a) of the main bearing (6).

2. Machine arrangement (1) according to claim 2, characterised in that the main bearing bracket lower part (6b) can be screwed to the main bearing bracket upper part (6a).

3. Machine arrangement (1) according to claim 1 or 2, characterised in that the bridge part (22) is firmly connected to the main bearing bracket upper part (6a) by means of at least two first fastening means (23), wherein preferably at least one first fastening means (23) is arranged so as to extend parallel to at least one main bearing screw (6c) of the main bearing (6) of the internal combustion engine (2).

4. Machine arrangement (1) according to one of claims 1 to 3, characterised in that the housing (12) of the electric machine (11) is connected to the bridge part (22) via second fastening means (26), wherein preferably at least three or four second fastening means (26) are provided, which are particularly preferably positioned around the rotor axis (14a).

5. Machine arrangement (1) according to claim 4, characterised in that an end of the rotor (14) protruding from the housing (12) of the electric machine (11) extends through a recess (39) in the crankcase (3) bounded by a wall region (30), wherein the housing (12) is arranged on a first side and the bridge part (22) is arranged on a second side of the wall region (30) opposite the first side, and the housing (12) is pressed against the wall region (30) of the crankcase by means of the second fastening means (26) in a region at least partially concentrically surrounding the rotor axis (14a), wherein preferably at least one outer sealing element (67) is provided between the wall region (30) and the housing (12), which sealing element is mounted in a corresponding recess in the housing (11) or the wall region (30).

6. Machine arrangement (1) according to one of claims 1 to 5, characterised in that the gear stage (15) has at least one rotor gear (16) connected in a rotationally fixed manner to the rotor (14) and at least one crankshaft gear (9) operatively connected to the rotor gear (16) and connected in a rotationally fixed manner to the crankshaft (7), wherein preferably the gear stage (15) has at least one intermediate gear (17) which is in meshing engagement with the rotor gear (16) and / or with the crankshaft gear (9).

7. Machine arrangement (1) according to claim 6, characterised in that the intermediate gear (17) is rotatably mounted on an intermediate gear carrier (33), which intermediate gear carrier (33) is fastened to the bridge part (22), preferably via third fastening means (34), which are particularly preferably designed as screws.

8. Machine arrangement (1) according to one of claims 1 to 7, characterised in that the bridge part (22) and / or the intermediate gear carrier (33) is formed in each case by a plate-shaped element arranged essentially parallel to the gear plane (ε).

9. Machine arrangement (1) according to one of claims 1 to 8, characterised in that the bridge part (22) and / or the intermediate gear carrier (33) have a higher modulus of elasticity than the crankcase (3), wherein preferably the bridge part (22) and / or the intermediate gear carrier (33) has or have a higher modulus of elasticity than the main bearing bracket upper part (6a).

10. Machine arrangement (1) according to one of claims 1 to 9, characterised in that the bridge part (22) and / or the intermediate gear carrier (33) have a higher resistance moment about the rotor axis (14a) or about the crankshaft axis (7a) than a corresponding wall region (30) of the crankcase (3), in particular between the rotor axis (14a) and the crankshaft axis (7a).

11. Machine arrangement (1) according to one of claims 1 to 10, characterised in that the bridge part (22) and / or the intermediate gear carrier (33) and / or the main bearing bracket upper part (6a) is / are made of steel.

12. Machine arrangement (1) according to one of claims 1 to 11, characterised in that the crankcase (3) is made of light metal.