An integrated toothed chain transmission case structure suitable for split crankcases

Abstract

The application discloses an integrated sprocket chain transmission box structure suitable for a split crankcase, which comprises an integrated transmission box shell; an installation interface for being connected with the split crankcase is arranged on the upper portion of the integrated transmission box shell; an integrated cooling water cavity is arranged in the integrated transmission box shell; a transmission component installation unit for installing corresponding transmission sprocket wheels is arranged on the integrated transmission box shell; and an integrated lubricating oil channel assembly is arranged on the integrated transmission box shell. The application solves the problems of the traditional transmission box, such as being unable to adapt to the split crankcase, single function and loose overall arrangement, realizes the lightweight design of the engine through the integration of the transmission, cooling and lubrication functions, reduces the sealing points, optimizes the overall layout, improves the reliability of the transmission system and is suitable for the timing chain transmission system of the split crankcase engine.

Description

Technical Field

[0001] This invention belongs to the technical field of internal combustion engine transmission systems, and in particular relates to an integrated geared chain transmission box structure suitable for split crankcases. Background Technology

[0002] Currently, in the field of internal combustion engines, traditional transmission cases primarily serve the function of fixing gears or sprockets. They are functionally simple, structurally relatively straightforward, and often consist of independent mounting housings. The design of these transmission cases is mainly adapted to integral crankcases, and their structural layout only meets the installation and positioning requirements of transmission components, without considering deep integration with the engine's cooling and lubrication systems.

[0003] Problems with existing technology: (1) Poor adaptability: Traditional transmission boxes cannot adapt to the structural characteristics of split crankcases. The installation of transmission components, cooling and lubrication system of split crankcase engines are difficult to be compatible with existing transmission boxes. (2) Low integration: The cooling and lubrication related structures are not integrated, and the engine needs to be arranged with separate cooling pipes and lubrication oil lines. The overall structure is loose and occupies a lot of space. (3) Poor weight reduction effect: Independent cooling and lubrication pipelines and related housing components increase the overall weight of the engine, which is not conducive to the lightweight design of the engine; (4) Insufficient sealing and compactness: Additional pipeline connections increase sealing points and increase the risk of leakage. At the same time, the overall engine layout is not compact enough and the space utilization rate is low. Summary of the Invention

[0004] In view of this, the present invention aims to provide an integrated geared chain drive structure suitable for split crankcases, in order to solve at least one technical problem in the background art.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: An integrated geared chain drive structure suitable for split crankcases includes an integral drivecase housing; The upper part of the integrated transmission housing is provided with a mounting interface for connection with the split crankcase; An integrated cooling water chamber is provided inside the integrated transmission housing. The cooling water chamber is a closed cavity structure and is located inside the transmission housing to connect with the engine cooling system to achieve coolant circulation. The integrated transmission housing is equipped with a transmission component mounting unit for mounting the corresponding transmission sprocket; An integrated lubrication channel assembly is provided on the integrated transmission housing. The integrated lubrication channel assembly is a hidden oil channel inside the transmission housing. One end of the integrated lubrication channel assembly is into which lubricating oil enters, and the other end extends to the lubrication point of the transmission component.

[0006] Furthermore, the transmission component mounting unit includes a left camshaft sprocket hole, a right camshaft sprocket hole, a crankshaft sprocket hole, and an oil pump / water pump sprocket hole; The sprocket holes of the left camshaft and the right camshaft are respectively located on the left and right sides of the integrated transmission housing. The crankshaft sprocket hole and the oil pump / water pump sprocket hole are arranged sequentially from top to bottom in the middle of the integrated transmission housing.

[0007] Furthermore, the integrated lubrication oil passage assembly includes a lubrication oil inlet for the left cylinder head, a lubrication oil inlet for the first engine block, a lubrication oil inlet for the second engine block, and a lubrication oil inlet for the right cylinder head; The lubricating oil inlet for the left cylinder head and the lubricating oil inlet for the right cylinder head are respectively located on both sides of the upper part of the integrated transmission housing. The first and second engine block lubricating oil inlets are located on the integrated transmission housing, between the left cylinder head lubricating oil inlet and the right cylinder head lubricating oil inlet.

[0008] Furthermore, the lubricating oil inlet of the right cylinder head is connected to the first concealed oil passage; one end of the first concealed oil passage is located on the upper right side of the integrated transmission housing and serves as a lubrication point for the transmission components. The integrated transmission housing is provided with a first output pipe, and one side of the first output pipe is connected to the first concealed oil passage. The end of the first output pipe is located on the upper right side of the integrated transmission housing and serves as a lubrication point for the transmission components. The first concealed oil passage and the first output pipe are Y-shaped.

[0009] Furthermore, the second body lubricating oil inlet is connected to one end of the second output pipe; the other end of the second output pipe is located below the integrated transmission box housing and serves as the lubrication point for the transmission components. One side of the second output pipe is connected to one end of the third output pipe, and the other end of the third output pipe is located on the lower right side of the integrated transmission housing and serves as a lubrication point for the transmission components. The third output pipe is connected to the first output pipe.

[0010] Furthermore, the lubricating oil inlet of the first engine block is connected to the fourth output pipe, the lubricating oil inlet of the left cylinder head is connected to the fifth output pipe, one end of the fourth output pipe is located on the upper part of the integrated transmission housing and serves as the lubrication point for the transmission components; the other end is connected to the fifth output pipe. One end of the fifth output pipe is located on the upper part of the integrated transmission housing and serves as a lubrication point for the transmission components; the other end is connected to the fourth output pipe. Furthermore, the fourth output pipe is connected to the sixth output pipe, which is located on the lower left side of the integrated transmission housing and serves as a lubrication point for the transmission components.

[0011] Furthermore, the integrated cooling water chamber is located at the bottom and sides of the one-piece transmission housing, isolated from the lubrication oil passages and not directly connected; The lower left and right sides of the integrated transmission housing are provided with a first cooling water outlet and a second cooling water outlet, and the other side is provided with a first cooling water inlet and a second cooling water inlet.

[0012] Furthermore, a transmission box support structure is provided at the bottom of the integrated transmission box housing; The transmission box support structure includes support columns, with two support columns positioned on the left and right sides of the integrated transmission box housing.

[0013] Furthermore, the transmission housing is a cast integral structure, and the cooling water cavity and lubricating oil passage are integrally formed during the casting process.

[0014] Furthermore, the transmission housing is made of aluminum alloy or cast iron, and the mounting surface adapted to the split crankcase is directly fixed to the split crankcase by bolts.

[0015] Compared with existing technologies, the integrated gear chain drive structure for split crankcases described in this invention has the following advantages: 1. The high integration of this application allows for adaptation to split crankcases. The transmission box structure can be directly adapted to the installation interface of split crankcases, solving the problem that traditional transmission boxes cannot be adapted to split crankcases, and thus has a wider range of applications. 2. The integrated cooling water chamber in this application helps to reduce the weight of the whole machine. The integrated cooling water chamber structure inside the transmission box eliminates the need for additional independent cooling pipes, reducing the use of pipes and shell components, effectively reducing the weight of the whole machine, while optimizing the cooling path and improving cooling efficiency. 3. The integrated lubrication oil passage of this application optimizes the overall layout of the machine. The lubrication oil passage is integrated inside the transmission box to form a concealed oil passage structure and provides an oil inlet for the crankcase. This reduces the use of external oil pipes, reduces the number of sealing points, reduces the risk of leakage, and at the same time makes the engine layout more compact and significantly improves the space utilization. 4. This application has a compact structure and high reliability: by integrating the installation, cooling and lubrication functions of the transmission components into one unit, the connection links between components are reduced, the failure points are reduced, and the reliability of the whole machine operation is improved. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1This is a schematic diagram of the transmission box layout structure of the present invention (showing the overall shape of the transmission box, oil passages, oil inlet of the engine body, oil passage interface and installation interface). Figure 2 This is a schematic diagram of the internal water chamber and oil passage arrangement of the present invention (showing the distribution of the cooling water chamber inside the transmission box and the direction of the lubricating oil passage). Figure 3 This is a schematic diagram of the transmission box sprocket hole arrangement of the present invention (showing the positional distribution of the camshaft sprocket hole, crankshaft sprocket hole, and oil pump / water pump sprocket hole).

[0017] Explanation of reference numerals in the attached figures: 1. Integrated transmission housing; 2. Integrated cooling water chamber; 3. Left camshaft sprocket hole; 4. Right camshaft sprocket hole; 5. Crankshaft sprocket hole; 6. Oil pump / water pump sprocket hole; 7. Left cylinder head lubricating oil inlet; 8. Right cylinder head lubricating oil inlet; 9. First engine block lubricating oil inlet; 10. Second engine block lubricating oil inlet; 11. First concealed oil passage; 12. First output pipe; 13. Second output pipe; 14. Third output pipe; 15. Fourth output pipe; 16. Fifth output pipe; 17. Sixth output pipe; 18. Support column; 19. First cooling water outlet; 20. Second cooling water outlet; 21. First cooling water inlet; 22. Second cooling water inlet. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1 like Figures 1 to 3 As shown, the present invention provides an integrated gear chain transmission box structure suitable for split crankcases. Its core lies in highly integrating the three major functions of transmission component installation, coolant circulation, and lubricant delivery into a single integrated transmission box housing 1, thereby effectively solving the problems of poor adaptability and low integration of traditional transmission boxes.

[0023] See Figure 1 The integrated transmission housing 1 is a cast-in-place structure, preferably made of aluminum alloy or cast iron, to ensure sufficient structural strength and good heat dissipation. The upper part of the housing 1 is provided with a mounting interface that matches the split crankcase structure. This mounting interface is a precision-machined flat surface with multiple bolt holes, allowing the transmission housing 1 to be directly and firmly fixed to the corresponding mounting surface of the split crankcase using bolts, ensuring connection stability and sealing.

[0024] like Figure 3 As shown, the transmission component mounting unit specifically includes multiple sprocket mounting holes provided on the integrated transmission housing 1, which are used to provide a precise mounting reference for each sprocket in the toothed chain transmission system.

[0025] The left camshaft sprocket hole 3 and the right camshaft sprocket hole 4 are respectively located on the upper left and right sides of the integrated transmission housing 1, corresponding to the shaft ends of the left and right camshafts of the engine. The center distance and coaxiality of the two sprocket holes are strictly controlled during processing to ensure the installation accuracy of the camshaft sprockets, thereby ensuring the accuracy of the valve timing.

[0026] The crankshaft sprocket hole 5 is located in the middle of the integrated transmission housing 1, below the left and right camshaft sprocket holes. The position of this hole corresponds to the end of the engine crankshaft and serves as the power input reference for the transmission system.

[0027] Oil pump / water pump sprocket hole 6: Located in the lower middle part of the integrated transmission housing 1, below the crankshaft sprocket hole 5. This hole is used to install the sprockets driving the oil pump and water pump, realizing the power transmission from the crankshaft to the oil pump and water pump.

[0028] In a preferred embodiment, the integrated transmission housing 1 is further provided with chain guide mounting positions and tensioner mounting positions. These mounting positions are boss or groove structures with threaded holes, and the chain guide and tensioner can be directly fixed to the mounting positions by bolts without the need for additional transition supports, further simplifying the structure.

[0029] like Figure 2 As shown, the integrated transmission housing 1 has a cooling water chamber 2 inside. The cooling water chamber 2 is a closed cavity structure, and its distribution area mainly covers the bottom and left and right sides of the transmission housing to surround the sprocket drive area where heat is concentrated.

[0030] Specifically, the cooling water cavity 2 is directly formed inside the shell using a casting process. During casting, the cavity is formed by pre-placed sand cores. After casting, cleaning the sand cores yields a closed cooling water channel, eliminating the need for subsequent complex machining. The cooling water cavity 2 is equipped with an inlet (not shown in the figure) and an outlet. In one specific embodiment, see [reference needed]. Figure 1 and Figure 2 The lower left and right sides of the integrated transmission box housing 1 are respectively provided with a first cooling water outlet 19 and a second cooling water outlet 20, and the other side is provided with a first cooling water inlet 21 and a second cooling water inlet 22.

[0031] In actual installation, the inlet of the cooling water chamber 2 is connected to the coolant outlet on the engine block, while the outlet is connected to the return water pipe of the engine cooling system. Coolant flowing into this chamber during engine operation circulates within the transmission case, effectively carrying away heat generated by friction and power transmission in the transmission components, thus cooling the transmission case and surrounding components. This integrated design completely replaces traditional external cooling pipes, reducing the number of parts, optimizing the cooling path, and improving cooling efficiency.

[0032] See Figure 1 and Figure 2 The integrated transmission housing 1 is provided with an integrated lubrication oil passage assembly. This assembly is mainly a concealed oil passage structure located inside the transmission housing, used to deliver the lubricating oil from the engine's main oil passage to the lubrication points of each transmission component.

[0033] As a core part of the present invention, the integrated lubrication channel assembly includes multiple oil inlets and an interconnected network of dark oil channels.

[0034] Cylinder head lubrication oil passage Figure 1 As shown, the upper sides of the integrated transmission housing 1 are respectively provided with a left cylinder head lubricating oil inlet 7 and a right cylinder head lubricating oil inlet 8.

[0035] See Figure 2The right cylinder head lubricating oil inlet 8 is connected to the first concealed oil passage 11. One end of the first concealed oil passage 11 is connected to the first output pipe 12 located on the upper right side of the transmission housing. The end of the first output pipe 12 opens onto the housing surface, forming a lubrication point for the transmission components (e.g., for lubricating the right camshaft sprocket or related bearings). In a preferred embodiment, the first concealed oil passage 11 and the first output pipe 12 form a Y-shaped branch structure to achieve multi-path oil supply.

[0036] Similarly, the left cylinder head lubricating oil inlet 7 is connected to the fifth output pipe 16, and the end of the fifth output pipe 16 opens on the upper left side of the housing to form a lubrication point for the transmission component (used to lubricate the left camshaft sprocket or related bearings).

[0037] like Figure 1 As shown, in the middle of the integrated transmission housing 1, between the left and right cylinder head lubricating oil inlets, there is a first engine block lubricating oil inlet 9 and a second engine block lubricating oil inlet 10. These two inlets are used to connect with the main oil passage on the engine block to obtain pressurized lubricating oil.

[0038] See Figure 2 The second body lubricating oil inlet 10 is connected to one end of the second output pipe 13. The other end of the second output pipe 13 extends downward and opens below the integrated transmission housing 1, forming a lubrication point for the transmission components (e.g., for lubricating the crankshaft sprocket or the lower part of the chain). Simultaneously, one side of the second output pipe 13 is also connected to one end of a third output pipe 14, the other end of which opens to the lower right side of the integrated transmission housing 1, forming a lubrication point for the transmission components. The second output pipe 13 is used to supply oil to nearby tensioning components. In a more preferred embodiment, the third output pipe 14 may also be connected to the first output pipe 12, with the third output pipe 14 serving as a left-side auxiliary oil supply passage and the first output pipe 12 serving as a left-side air-distribution chain tensioner oil supply passage.

[0039] See Figure 2 The first engine block lubricating oil inlet 9 is connected to the fourth output pipe 15. One end of the fourth output pipe 15 opens into the upper part of the integrated transmission housing 1 (for example, in the area between the oil inlets of the left and right cylinder heads), forming a lubrication point for the transmission components (used to lubricate the upper area of ​​the chain or the intermediate guide wheel). The other end of the fourth output pipe 15 is connected to the fifth output pipe 16, realizing vertical connection of the left side oil passage. In addition, the fourth output pipe 15 is also connected to the sixth output pipe 17, which extends downward and opens into the lower left side of the integrated transmission housing 1, forming a lubrication point for the transmission components. The sixth output pipe 17 is used for the oil supply passage of the right side air distribution chain tensioner.

[0040] Through the aforementioned complex network of concealed oil channels, lubricating oil from the engine's main oil passage can be precisely and efficiently delivered to all critical friction pairs within the transmission case. All oil inlets and outlet pipes are integrally formed during the housing casting process, creating a closed internal oil passage.

[0041] like Figure 1 As shown, the bottom of the integrated transmission housing 1 is also provided with a transmission housing support structure. The support structure is preferably a support column 18, with two support columns 18 respectively disposed on the left and right bottom sides of the integrated transmission housing 1. The support column 18 is used to provide auxiliary support for the transmission housing during assembly or transportation, or, when installed on the engine, cooperates with the support seat on the engine block to enhance the structural rigidity and vibration resistance of the entire transmission system.

[0042] During assembly, first, the transmission housing 1 is bolted to the split crankcase via its mounting interface. Then, the camshaft sprocket, crankshaft sprocket, and oil pump / water pump sprocket are installed in the left camshaft sprocket hole 3, right camshaft sprocket hole 4, crankshaft sprocket hole 5, and oil pump / water pump sprocket hole 6, respectively. The chain guide and tensioner are then fixed in their pre-set mounting positions on the housing, completing the chain installation and tensioning.

[0043] In terms of lubrication, the pressurized lubricating oil of the engine main oil passage enters the hidden oil passage network inside the transmission box through the first engine block lubricating oil inlet 9, the second engine block lubricating oil inlet 10, the left cylinder head lubricating oil inlet 7, and the right cylinder head lubricating oil inlet 8, and is sprayed to the chain, sprocket meshing point, guide rail and bearing and other lubrication points through various output pipes (12-17) to achieve effective lubrication of the transmission system.

[0044] In terms of cooling, the engine coolant enters the integrated cooling water chamber 2, circulates at the bottom and sides of the transmission box, absorbs heat, and then flows out from the first cooling water outlet 19 and the second cooling water outlet 20, returning to the vehicle cooling system to complete the cooling cycle.

[0045] The transmission case of this invention is manufactured using a casting process and can be made of aluminum alloy or cast iron. It is integrally cast, with the cooling water chamber and lubrication oil passages directly formed during the casting process, requiring no subsequent machining. The mounting surface of the transmission case matches the mounting interface of the split crankcase, allowing for direct bolt fixation to the split crankcase for quick installation. The sprocket mounting holes correspond to the positions of the engine shafts, ensuring coaxiality after sprocket installation. The chain guide is bolted to the transmission case housing, and the tensioner is installed in the pre-reserved mounting position on the transmission case, cooperating with the chain guide to tension the chain. Lubricating oil enters the concealed oil passage through the engine block's oil inlet, forming a closed loop within the transmission case to provide continuous lubrication for the transmission components. Coolant enters the cooling water chamber and achieves cooling through circulation, eliminating the need for additional piping connections. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An integrated geared chain drive structure suitable for split crankcases, characterized in that: Includes an integrated transmission housing; The upper part of the integrated transmission housing is provided with a mounting interface for connection with the split crankcase; An integrated cooling water chamber is provided inside the integrated transmission housing. The cooling water chamber is a closed cavity structure and is located inside the transmission housing to connect with the engine cooling system to achieve coolant circulation. The integrated transmission housing is equipped with a transmission component mounting unit for mounting the corresponding transmission sprocket; An integrated lubrication channel assembly is provided on the integrated transmission housing. The integrated lubrication channel assembly is a hidden oil channel inside the transmission housing. One end of the integrated lubrication channel assembly is into which lubricating oil enters, and the other end extends to the lubrication point of the transmission component.

2. The integrated gear chain drive structure suitable for split crankcases according to claim 1, characterized in that: The transmission component mounting unit includes a left camshaft sprocket hole, a right camshaft sprocket hole, a crankshaft sprocket hole, and an oil pump / water pump sprocket hole; The sprocket holes of the left camshaft and the right camshaft are respectively located on the left and right sides of the integrated transmission housing. The crankshaft sprocket hole and the oil pump / water pump sprocket hole are arranged sequentially from top to bottom in the middle of the integrated transmission housing.

3. The integrated gear chain drive structure suitable for a split crankcase according to claim 1, characterized in that: The integrated lubrication system includes a lubricating oil inlet for the left cylinder head, a lubricating oil inlet for the first engine block, a lubricating oil inlet for the second engine block, and a lubricating oil inlet for the right cylinder head. The lubricating oil inlet for the left cylinder head and the lubricating oil inlet for the right cylinder head are respectively located on both sides of the upper part of the integrated transmission housing. The first and second engine block lubricating oil inlets are located on the integrated transmission housing, between the left cylinder head lubricating oil inlet and the right cylinder head lubricating oil inlet.

4. The integrated gear chain drive structure suitable for a split crankcase according to claim 3, characterized in that: The lubricating oil inlet of the right cylinder head is connected to the first hidden oil passage; one end of the first hidden oil passage is located on the upper right side of the integrated transmission housing and serves as the lubrication point for the transmission components. The integrated transmission housing is provided with a first output pipe, and one side of the first output pipe is connected to the first concealed oil passage. The end of the first output pipe is located on the upper right side of the integrated transmission housing and serves as a lubrication point for the transmission components. The first concealed oil passage and the first output pipe are Y-shaped.

5. The integrated gear chain drive structure suitable for a split crankcase according to claim 4, characterized in that: The second body lubricating oil inlet is connected to one end of the second output pipe; the other end of the second output pipe is located below the integrated transmission box housing and serves as the lubrication point for the transmission components. One side of the second output pipe is connected to one end of the third output pipe, and the other end of the third output pipe is located on the lower right side of the integrated transmission housing and serves as a lubrication point for the transmission components. The third output pipe is connected to the first output pipe.

6. The integrated gear chain drive structure suitable for a split crankcase according to claim 5, characterized in that: The first engine block lubricating oil inlet is connected to the fourth output pipe, the left cylinder head lubricating oil inlet is connected to the fifth output pipe, one end of the fourth output pipe is located on the upper part of the integrated transmission box housing and serves as the lubrication point for the transmission components; the other end is connected to the fifth output pipe. One end of the fifth output pipe is located on the upper part of the integrated transmission housing and serves as a lubrication point for the transmission components; the other end is connected to the fourth output pipe. Furthermore, the fourth output pipe is connected to the sixth output pipe, which is located on the lower left side of the integrated transmission housing and serves as a lubrication point for the transmission components.

7. The integrated gear chain drive structure suitable for a split crankcase according to claim 1, characterized in that: The integrated cooling water chamber is located at the bottom and sides of the one-piece transmission housing, and is isolated from the lubrication oil passages and has no direct connection. The lower left and right sides of one side of the integrated transmission box housing are provided with a first cooling water outlet and a second cooling water outlet, and the other side is provided with a first cooling water inlet and a second cooling water inlet.

8. The integrated gear chain drive structure suitable for a split crankcase according to claim 1, characterized in that: The bottom of the integrated transmission box housing is equipped with a transmission box support structure; The transmission box support structure includes support columns, with two support columns positioned on the left and right sides of the integrated transmission box housing.

9. The integrated gear chain drive structure suitable for a split crankcase according to claim 1, characterized in that: The transmission housing is a one-piece structure formed by casting, and the cooling water cavity and lubrication oil passage are formed as a single piece during the casting process.

10. The integrated gear chain drive structure suitable for a split crankcase according to claim 1, characterized in that: The transmission housing is made of aluminum alloy or cast iron, and the mounting surface adapted to the split crankcase is directly fixed to the split crankcase with bolts.

Images