Assembly tool and assembly method

Abstract

The present invention discloses an assembly tool and an assembly method, which are applied to the assembly of a mechanical transmission device of a variable compression ratio engine, and achieve the technical effect of ensuring the installation alignment accuracy of the two without observing the position, while improving the assembly efficiency. The assembly tool comprises a tool body; a meshing tooth provided at the first end of the tool body, which is used to mesh with the synchronous roller of the mechanical transmission device, and the meshing tooth and / or the tool body are magnetic; a positioning part provided at the second end of the tool body, which is used to connect the engine cylinder of the variable compression ratio engine; a limiting step provided at the first end of the tool body, which is used to match the combustion tooth plate of the mechanical transmission device when the positioning part is connected to the engine cylinder of the variable compression ratio engine, and solves the quality problem of the prior art that installation errors are prone to occur, which affects the engine efficiency and service life.

Description

Technical Field

[0001] The present invention relates to the technical field of variable compression ratio engines, and particularly to an assembly tooling and a variable compression ratio engine assembly method. Background Art

[0002] A variable compression ratio engine is a technology that can dynamically change the compression ratio of the engine. Different compression ratios are adopted according to different loads of the engine, that is, a high compression ratio is used under low load conditions to improve the thermal efficiency, and a low compression ratio is used under high load conditions to ensure the power performance. The mechanical transmission device of the variable compression ratio engine includes at least one cylinder in which a piston can move. The lower part of the piston is fixed to a transmission member. One side of the transmission member moves synchronously with a synchronous roller guide device through a synchronous tooth plate, and the other side meshes with a transmission gear fixed to a connecting rod through a combustion tooth plate, so as to transmit motion between the piston and the connecting rod.

[0003] However, in the actual production process, the structure of the variable compression ratio engine is complex. Especially, the assembly process of the synchronous roller is the difficulty for the mass production of the whole variable compression ratio engine mechanism. It is difficult to assemble by ordinary processes, with low operation efficiency, and it is easy to have installation errors, resulting in quality problems such as affecting the engine efficiency and service life. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides an assembly tooling and an assembly method, achieving the technical effect of ensuring the installation alignment accuracy of the two without observing the position. At the same time, the assembly efficiency is improved, and the installation quality of the variable compression ratio engine is ensured.

[0005] The solution for achieving the technical object of the present invention is an assembly tooling applied to the assembly of the mechanical transmission device of a variable compression ratio engine. The assembly tooling includes:

[0006] A tooling body;

[0007] Engaging teeth are provided at the first end of the tooling body for meshing with the synchronous roller of the mechanical transmission device. The engaging teeth and / or the tooling body have magnetism;

[0008] A positioning portion is provided at the second end of the tooling body for connecting to the engine cylinder block of the variable compression ratio engine;

[0009] A limiting step is provided at the first end of the tooling body for matching with the combustion tooth plate of the mechanical transmission device in a state where the positioning portion is connected to the engine cylinder block of the variable compression ratio engine.

[0010] Further, the meshing teeth are arc-shaped racks for accommodating the synchronous rollers, the central angle of the meshing teeth is less than 180°, and the opening size of the meshing teeth near the first end is larger than that near the second end.

[0011] Further, the central angle of the meshing teeth is 10°-90°.

[0012] Based on the same inventive concept, the present invention also provides an assembly method based on the above assembly tooling for assembling a mechanical transmission device of a variable compression ratio engine. The assembly method includes the following steps:

[0013] Assemble the combustion piston assembly, the control piston assembly, and the transmission gear of the mechanical transmission device into the engine cylinder block of the variable compression ratio engine, and make the transmission gear mesh with both the combustion tooth plate of the combustion piston assembly and the control tooth plate of the control piston assembly at the same time;

[0014] Connect the positioning part of the assembly tooling to the engine cylinder block so that the first end of the assembly tooling extends into the engine cylinder block;

[0015] Axially move the combustion piston assembly to a position where the combustion tooth plate abuts against the limiting step;

[0016] Assemble the synchronous roller of the mechanical transmission device into the engine cylinder block so that the synchronous roller meshes with the meshing teeth under the magnetic attraction and also meshes with the combustion tooth plate; install the synchronous tooth plate of the mechanical transmission device of the variable compression ratio engine onto the engine cylinder block so that the synchronous roller meshes between the combustion tooth plate and the synchronous tooth plate;

[0017] Dismantle the assembly tooling, install the engine crankshaft, and complete the assembly of the mechanical transmission device of the variable compression ratio engine.

[0018] Further, the step of axially moving the combustion piston assembly to a position where the combustion tooth plate abuts against the limiting step specifically includes

[0019] Position the control piston assembly and the transmission gear; under the action of a first pressing force F1 in a direction parallel to the axis of the combustion piston assembly, axially move the combustion piston assembly to a position where the combustion tooth plate abuts against the limiting step.

[0020] Further, before assembling the synchronous roller into the engine cylinder block, the assembly method further includes, under the action of a second pressing force F2 having a component force perpendicular to the control tooth plate, transmitting the second pressing force F2 to the transmission gear to position the combustion tooth plate and the transmission gear.

[0021] Furthermore, the application direction of the first pressing force F1 is perpendicular to the application direction of the second pressing force F2.

[0022] Furthermore, the position where the combustion tooth plate abuts against the limiting step is set as the bottom dead center of the combustion piston assembly.

[0023] Furthermore, the first pressing force F1 is 5N - 10N; the second pressing force F2 is 4N - 6N.

[0024] Furthermore, the assembly of the combustion piston assembly, the control piston assembly and the transmission gear into the engine cylinder block specifically includes:

[0025] Install the combustion piston assembly into the engine cylinder block, engage the control tooth plate and the transmission gear, and install the engaged transmission gear and control tooth plate together into the engine cylinder block so that the transmission gear meshes with the end of the combustion tooth plate away from the combustion piston.

[0026] Axially move the combustion piston assembly to the upper dead center to the set installation position, and install the control piston on the control tooth plate to obtain the control piston assembly.

[0027] Furthermore, before installing the combustion piston assembly, the control piston, and the engaged control tooth plate and transmission gear into the engine cylinder block, the assembly method further includes:

[0028] Place the engine cylinder block in a posture where the combustion tooth plate is parallel to the horizontal plane and the synchronous roller is located above the combustion tooth plate.

[0029] The removal of the assembly tooling and the installation of the engine crankshaft specifically include removing the assembly tooling, flipping the engine cylinder block so that the combustion tooth plate is perpendicular to the horizontal plane, and installing the engine crankshaft.

[0030] As can be seen from the above technical solution, an assembly tooling for assembling a mechanical transmission device applied to a variable compression ratio engine provided by the present invention includes a tooling body, a positioning portion respectively provided at the second end of the tooling body, and a meshing tooth and a limiting step provided at the first end of the tooling body. Among them, the positioning portion is used to connect the engine block of the variable compression ratio engine to fix the tooling body on the engine block and make the first end of the tooling body extend into the engine block. The limiting step is used to match with the combustion tooth plate of the variable compression ratio engine at a set position and axially position the combustion tooth plate when the positioning portion is connected to the engine block of the variable compression ratio engine. The meshing tooth is used to mesh with the synchronous roller of the variable compression ratio engine. The meshing tooth and / or the tooling body has magnetism, so that the synchronous roller is positioned under the magnetic attraction and meshes with the meshing tooth and the combustion tooth plate at the same time, thereby ensuring the accurate installation of the synchronous roller on the combustion tooth plate, achieving the technical effect of ensuring the accurate installation and alignment of the two without observing the position, and improving the assembly efficiency at the same time.

[0031] The assembly method provided by the present invention is implemented based on the above assembly tooling and is used for assembling the mechanical transmission device of the variable compression ratio engine, including the following steps:

[0032] Assemble the combustion piston assembly, control piston assembly and transmission gear of the mechanical transmission device into the engine block of the variable compression ratio engine, and make the transmission gear mesh with the combustion tooth plate of the combustion piston assembly and the control tooth plate of the control piston assembly at the same time to achieve transmission;

[0033] Connect the positioning portion of the assembly tooling to the engine block so that the first end of the assembly tooling extends into the engine block;

[0034] Axially move the combustion piston assembly to the position where the combustion tooth plate abuts against the limiting step; to ensure the position of the combustion tooth plate is fixed by the limiting step and prepare for the installation of the synchronous roller and the alignment and meshing of the three;

[0035] Assemble the synchronous roller of the mechanical transmission device into the engine block so that the synchronous roller meshes with the meshing tooth under the magnetic attraction and meshes with the combustion tooth plate; install the synchronous tooth plate of the mechanical transmission device of the variable compression ratio engine on the engine block so that the synchronous roller meshes between the combustion tooth plate and the synchronous tooth plate;

[0036] Remove the assembly tooling, install the engine crankshaft, and complete the assembly of the mechanical transmission device of the variable compression ratio engine.

[0037] The assembly tooling and assembly method provided by the present invention realize the connection with the engine block and the positioning of the combustion tooth plate by using the tooling body with a positioning part and a limiting step. The synchronous roller is adsorbed by the tooling body with meshing teeth and magnetism to be meshed with both the meshing teeth and the combustion tooth plate at the same time, effectively solving the installation problem of the combustion piston and the synchronous roller of the variable compression ratio engine. The measurement accuracy and installation accuracy are effectively guaranteed, and the operation efficiency is also significantly improved. The assembly of the variable compression ratio engine mechanism is realized, the industrialization problem of the variable compression ratio engine is solved, and it has the production capacity. Brief Description of the Drawings

[0038] Figure 1 It is a schematic structural diagram of the assembly tooling provided in Embodiment 1 of the present invention;

[0039] Figure 2 is Figure 1 a schematic diagram of the assembly tooling in [] being applied to the assembly of the mechanical transmission device of the variable compression ratio engine;

[0040] Figure 3 It is a flow block diagram of the assembly method provided in Embodiment 2 of the present invention.

[0041] Brief Description of the Drawings: 10 - assembly tooling, 11 - tooling body, 12 - meshing teeth, 13 - positioning part, 14 - limiting step; 20 - mechanical transmission device, 21 - combustion piston, 22 - combustion tooth plate, 23 - transmission gear, 24 - control piston, 25 - control tooth plate, 26 - synchronous roller, 27 - synchronous tooth plate, 28 - connecting rod; 30 - engine block. Detailed Embodiments

[0042] In order to enable those skilled in the art in the technical field to which the present application belongs to understand the present application more clearly, the technical solutions of the present application will be described in detail below with reference to the drawings through specific embodiments.

[0043] The mechanical transmission device of a variable compression ratio engine includes at least one cylinder in which a piston can move. The lower part of the piston is fixed to a transmission member. One side of the transmission member moves synchronously with a synchronous roller guide device through a synchronous toothed plate, and the other side meshes with a transmission gear fixed to a connecting rod through a combustion toothed plate, so as to transmit motion between the piston and the connecting rod. The mechanical transmission device of the variable compression ratio engine should also include: a control toothed plate meshing with the teeth on the other side of the transmission gear, and a device for fixing the position of the control toothed plate and absorbing the load transmitted from the piston to the control toothed plate. Therefore, a hydraulic device should be arranged on the other side of the control toothed plate to keep the guide rails of the main moving parts of the power transmission device of the variable compression ratio engine in persistent contact. It should be noted that a device for fixing the control toothed plate and absorbing the load transmitted from the piston to the control toothed plate should be provided. This device should include a hydraulic chamber and a control piston. The control piston is fixed to the rod part of the control toothed plate, and the hydraulic chamber is filled with engine oil. When the compression ratio needs to be adjusted, the engine oil on both sides of the control piston in the hydraulic chamber should be able to flow to each other. To control the compression ratio adjustment, electric control one-way valves should be arranged on the hydraulic chambers on both sides of the control piston, and the two one-way valves are connected through an external pipeline. The height in the hydraulic chamber is adjusted through the electric control one-way valves to control the internal compression ratio of the engine.

[0044] For the variable compression ratio engine, during the trial production process, the assembly of parts mainly relies on skilled operators for manual assembly. Due to the relatively complex structure of the engine, especially the installation of the combustion piston assembly and the synchronous roller inside the engine cylinder block, the operation process cannot be effectively observed. Moreover, after the synchronous roller is installed, it is necessary to ensure meshing with the gear on one side of the combustion toothed plate, and the installation accuracy cannot be effectively guaranteed, and the assembly efficiency is low. Therefore, it has become a difficult point in the assembly of this variable compression ratio engine mechanism.

[0045] In order to solve the problems in the prior art such as the difficult assembly of the synchronous roller and the combustion piston assembly, the low operation efficiency, and the easy occurrence of installation errors, which may affect the engine efficiency and service life and other quality problems, the present invention provides an assembly method and an assembly tooling, achieving the technical effect of ensuring the installation alignment accuracy of the two without observing the position, and at the same time improving the assembly efficiency. The following is a detailed introduction to the specific content of the present invention through two embodiments:

[0046] Embodiment 1

[0047] This embodiment provides an assembly tooling 10 for the assembly of a mechanical transmission device 20 applied to a variable compression ratio engine, including a tooling body 11, a positioning portion 13 respectively disposed at the second end of the tooling body 11, an engaging tooth 12 and a limiting step 14 disposed at the first end of the tooling body 11. Among them, the positioning portion 13 is used to connect the engine block 30 of the variable compression ratio engine to fix the tooling body 11 on the engine block 30 and make the first end of the tooling body 11 extend into the engine block 30. The limiting step 14 is used to match with the combustion tooth plate 22 of the variable compression ratio engine at a set position and axially position the combustion tooth plate 22 in the state where the positioning portion 13 is connected to the engine block 30 of the variable compression ratio engine. The engaging tooth 12 is used to engage with the synchronous roller 26 of the variable compression ratio engine. The engaging tooth 12 and / or the tooling body 11 has magnetism, so that the synchronous roller 26 is positioned under the magnetic attraction effect and simultaneously engages with the engaging tooth 12 and the combustion tooth plate 22, thereby ensuring the installation of the synchronous roller 26 in place on the combustion tooth plate 22, achieving the technical effect of ensuring the installation alignment accuracy of the two without observing the position, and improving the assembly efficiency at the same time.

[0048] This application mainly makes the synchronous roller 26 adsorb and engage with the engaging tooth 12 through the magnetic attraction effect. Since the first end of the second end abuts against the end face of the combustion tooth plate 22 through the limiting step 14, the engaging tooth 12 is located on the side where the combustion tooth plate 22 meshes with the synchronous roller 26. By designing the size and position of the assembly tooling 10 to just make the synchronous roller 26 mesh with the engaging tooth 12 and the combustion tooth plate 22 at the same time, the position of the synchronous roller 26 is directly determined by the assembly tooling 10, and then the synchronous tooth plate 27 is installed, so that the synchronous roller 26 meshes and transmits between the combustion tooth plate 22 and the synchronous tooth plate 27.

[0049] This application does not specifically limit the magnetic attraction portion of the assembly tooling 10. In some embodiments, the engaging tooth 12 can have magnetism. In some other embodiments, it can also be that the tooling body 11 has magnetism. In some embodiments, the engaging tooth 12 and the tooling body 11 can also have magnetism.

[0050] In order to ensure the positioning effect and the smoothness of the assembly, in some embodiments, the engaging tooth 12 is an arc-shaped rack for accommodating the synchronous roller 26, and the central angle of the engaging tooth 12 is less than 180°. The opening size of the engaging tooth 12 near the first end is larger than the opening size near the second end to avoid hindering the meshing installation of the synchronous tooth plate 27 and the synchronous roller 26.

[0051] The installation operation space in the engine block 30 is limited. In order to take into account the meshing assembly of the synchronous roller 26 with the combustion tooth plate 22 and the synchronous tooth plate 27 at the same time, preferably, the central angle of the engaging tooth 12 is 10° - 90°.

[0052] In order to avoid hindering the meshing installation of the transmission gear 23 of the mechanical transmission device 20 and the combustion tooth plate 22, preferably, in this embodiment, the meshing teeth 12 and the limiting step 14 are located on different sides of the first end of the tooling body 11, that is, the limiting step 14 contacts the side of the combustion tooth plate 22 for meshing with the synchronous roller 26.

[0053] In order to detachably connect the assembly tooling 10 to the engine block 30, in this embodiment, at least two threaded through holes are provided on the assembly tooling 10, and it can be detachably connected to the engine block 30 through fixing bolts.

[0054] An assembly tooling 10 provided by the present invention is used for detachably setting on the engine block 30 of a variable compression ratio engine; the assembly tooling 10 has a magnetic gear structure meshing with the synchronous roller 26 and a limiting step 14 for accommodating the end of the combustion tooth plate 22, and the magnetic gear structure and the limiting step 14 are located on different sides, so that while the combustion tooth plate 22 is positioned by the assembly tooling 10, the magnetic gear structure is located on the gear side of the combustion tooth plate 22. When the synchronous roller 26 is placed in, it can be meshed and fixed to the combustion tooth plate 22 under the action of magnetic adsorption force, effectively ensuring the measurement accuracy and installation accuracy, and significantly improving the operation efficiency.

[0055] Embodiment 2

[0056] Based on the same inventive concept, this embodiment provides an assembly method implemented based on the assembly tooling 10 of Embodiment 1, including the following steps:

[0057] Assemble the combustion piston 21 assembly, the control piston 24 assembly and the transmission gear 23 of the mechanical transmission device 20 into the engine block 30 of the variable compression ratio engine, and make the transmission gear 23 mesh with both the combustion tooth plate 22 of the combustion piston 21 assembly and the control tooth plate 25 of the control piston 24 assembly at the same time to achieve transmission;

[0058] Connect the positioning part 13 of the assembly tooling 10 to the engine block 30 so that the first end of the assembly tooling 10 extends into the engine block 30;

[0059] Axially move the combustion piston 21 assembly to the position where the combustion tooth plate 22 abuts against the limiting step 14; to ensure the position of the combustion tooth plate 22 is fixed through the limiting step 14 and prepare for the installation of the synchronous roller 26 and the alignment and meshing of the three;

[0060] Assemble the synchronous roller 26 of the mechanical transmission device 20 into the engine block 30 so that the synchronous roller 26 meshes with the meshing teeth 12 under the magnetic attraction and also meshes with the combustion tooth plate 22; install the synchronous tooth plate 27 of the variable compression ratio engine mechanical transmission device 20 onto the engine block 30 so that the synchronous roller 26 meshes between the combustion tooth plate 22 and the synchronous tooth plate 27;

[0061] Remove the assembly tooling 10 and install the engine crankshaft to complete the assembly of the mechanical transmission device 20 of the variable compression ratio engine.

[0062] The assembly method provided by the present invention realizes the connection with the engine block 30 and the positioning of the combustion tooth plate 22 by using the tooling body 11 with the positioning portion 13 and the limiting step 14. The synchronous roller 26 is adsorbed by the tooling body 11 with the meshing teeth 12 and magnetism to mesh with both the meshing teeth 12 and the combustion tooth plate 22 at the same time, effectively solving the installation problem of the combustion piston 21 and the synchronous roller 26 of the variable compression ratio engine. The measurement accuracy and installation accuracy are effectively guaranteed, and the operation efficiency is also significantly improved. The assembly of the variable compression ratio engine mechanism is realized, the industrialization problem of the variable compression ratio engine is solved, and it has the production capacity.

[0063] This application does not specifically limit the axial movement of the combustion piston 21 assembly, and only needs to ensure that the force applied to the combustion piston 21 assembly has a component parallel to the axis direction of the combustion piston 21 assembly. Due to the limited operable space, in this embodiment, the combustion piston 21 assembly is axially moved to the position where the combustion tooth plate 22 abuts against the limiting step 14, specifically including positioning the control piston 24 assembly and the transmission gear 23; under the action of the first pressing force F1 parallel to the axis direction of the combustion piston 21 assembly, the combustion piston 21 assembly is axially moved to the position where the combustion tooth plate 22 abuts against the limiting step 14.

[0064] In order to avoid damage to the structure of the combustion tooth plate 22 caused by increasing the first pressing force to ensure the fixation of the combustion tooth plate 22, in this embodiment, before assembling the synchronous roller 26 into the engine block 30, the assembly method further includes that under the action of the second pressing force F2 with a component perpendicular to the control tooth plate 25, the second pressing force F2 is transmitted to the transmission gear 23 to position the combustion tooth plate 22 and the transmission gear 23, so as to transmit the force to the transmission gear 23 through the control tooth plate 25 and provide a binding force in another direction to the combustion tooth plate 22, which can ensure that the first pressing force is within a small range.

[0065] Similarly, due to the limited operable space on the side of the engine block 30, in this embodiment, preferably, the application direction of the first pressing force F1 is perpendicular to the application direction of the second pressing force F2.

[0066] For the convenience of design positioning, preferably, in this embodiment, the position where the combustion tooth plate 22 abuts against the limiting step 14 is set as the bottom dead center of the combustion piston 21 assembly.

[0067] To avoid the misalignment of the transmission gear 23 caused by excessive second pressing force, when installing the synchronous roller 26, pressing forces need to be applied on both sides of the combustion piston 21 and the control tooth plate 25. In this embodiment, preferably, the first pressing force F1 is 5N - 10N; the second pressing force F2 is 4N - 6N.

[0068] To ensure the alignment and cooperation of other parts, the combustion piston 21 assembly, the control piston 24 assembly and the transmission gear 23 are assembled into the engine cylinder block 30, specifically including,

[0069] Install the combustion piston 21 assembly into the engine cylinder block 30, engage the control tooth plate 25 and the transmission gear 23, and install the engaged transmission gear 23 and control tooth plate 25 together into the engine cylinder block 30 so that the transmission gear 23 meshes with the end of the combustion tooth plate 22 away from the combustion piston 21;

[0070] Axially move the combustion piston 21 assembly to the upper dead center to the set installation position, and install the control piston 24 on the control tooth plate 25 to obtain the control piston 24 assembly.

[0071] Since the synchronous roller 26 needs to be in full contact and mesh with the tooth structure on the combustion tooth plate 22, in this embodiment, before installing the combustion piston 21 assembly, the control piston 24, and the engaged control tooth plate 25 and transmission gear 23 into the engine cylinder block 30, the assembly method further includes:

[0072] Place the engine cylinder block 30 in a posture where the combustion tooth plate 22 is parallel to the horizontal plane and the synchronous roller 26 is located above the combustion tooth plate 22; so that the synchronous roller 26 is placed on the combustion tooth plate 22 under its own weight, avoiding misalignment and improving the alignment accuracy.

[0073] To facilitate the installation of the engine crankshaft, remove the assembly tooling 10 and install the engine crankshaft, specifically including, removing the assembly tooling 10, flipping the engine cylinder block 30 so that the combustion tooth plate 22 is perpendicular to the horizontal plane, and installing the engine crankshaft.

[0074] The present invention does not specifically limit the structure of the combustion piston 21 assembly. An integral structure can be selected, or a split structure can be used. In this embodiment, the combustion piston 21 assembly is of a split structure, including a combustion piston 21, a piston stud nut, a piston stud, and a combustion tooth plate 22. The assembly method further includes assembling the combustion piston 21 assembly and fixing the combustion piston 21; screwing the piston stud nut into the combustion piston 21, and screwing the piston stud into the piston stud nut; tightening the combustion tooth plate 22 onto the piston stud, and fixing the combustion tooth plate 22 and the combustion piston 21 through a connecting pin; ensuring the connection strength.

[0075] The assembly method provided in this embodiment includes the following steps:

[0076] (1) After placing the engine block 30 in a horizontal state, install the combustion piston 21 assembly into the engine block 30.

[0077] (2) Mesh the control tooth plate 25 and the transmission gear 23, align the ends of the transmission gear 23 and the combustion tooth plate 22, and install them together into the engine block 30.

[0078] (3) Push the control tooth plate 25, the transmission gear 23, and the combustion tooth plate 22 together to the top dead center, and insert the control tooth plate 25 into the small hole of the control piston 24.

[0079] (4) Install the magnetic assembly tool 10 onto the engine block 30. At the same time, use the first pressing force F1 to retract the combustion piston 21 to the bottom dead center, and ensure that the lower edge of the combustion tooth plate 22 contacts the assembly tool 10. Control the magnitude of the first pressing force F1 to be 5 N to 10 N.

[0080] (5) After using the second pressing force F2 to press the control tooth plate 25, place the synchronous roller 26 from the side of the engine block 30 onto the combustion tooth plate 22, and adsorb and align it with the magnetic meshing tooth 12. The magnitude of the second pressing force F2 is 4 N to 6 N.

[0081] (6) Install the synchronous tooth plate 27 and tighten its fixing bolts.

[0082] (7) Flip the engine block 30, install the engine crankshaft, and connect the transmission gear 23 and the engine crankshaft through the connecting rod 28 for transmission, completing the assembly of the mechanical transmission device 20 in the engine block 30. And complete other components of the variable compression ratio engine before step (1), in the middle of steps (1)-(7), or after step (7), and a complete variable compression ratio engine can be obtained.

[0083] An assembly method provided by the present invention uses two pressing forces to fix the positions of the combustion piston 21 and the control piston 24, and then the magnetic assembly tooling 10 effectively protects the state of the components. At the same time, it adsorbs the synchronous roller 26, ensuring the correct meshing of the combustion gear and the synchronous roller 26 during the installation process, ensuring the proper installation of the synchronous roller 26, improving the production efficiency and the installation quality, effectively solving the installation problem of the combustion piston 21 and the synchronous roller 26 of the variable compression ratio engine, effectively guaranteeing the measurement accuracy and the installation accuracy, and significantly improving the operation efficiency.

[0084] Through the above embodiments, the present invention has the following beneficial effects or advantages:

[0085] The assembly method and the assembly tooling provided by the present invention achieve the technical effect of ensuring the installation alignment accuracy of the two without observing the position, and at the same time improve the assembly efficiency. Using two pressing forces to fix the positions of the combustion piston and the control piston, and then the magnetic assembly tooling effectively protects the state of the components. At the same time, it adsorbs the synchronous roller, ensuring the correct meshing of the combustion gear and the synchronous roller during the installation process, ensuring the proper installation of the synchronous roller, improving the production efficiency and the installation quality, effectively solving the installation problem of the combustion piston and the synchronous roller of the variable compression ratio engine, avoiding the transmission problems caused by low meshing accuracy and the technical problems of short engine life, effectively guaranteeing the measurement accuracy and the installation accuracy, and significantly improving the operation efficiency.

[0086] Although the preferred embodiments of the present application have been described, those of ordinary skill in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0087] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. An assembly tool, characterized in that: The assembly of a mechanical transmission device applied to a variable compression ratio engine, the assembly tool comprising: Tool body; An engagement tooth, provided at the first end of the tool body, for engaging with the synchronous roller of the mechanical transmission device, wherein the engagement tooth and / or the tool body is magnetic; A positioning portion, provided at the second end of the tooling body, for connecting to an engine cylinder block of the variable compression ratio engine; A limiting step is provided at the first end of the tooling body and is used to match the combustion tooth plate of the mechanical transmission device when the positioning portion is connected to the engine cylinder block of the variable compression ratio engine.

2. The assembly tool according to claim 1, characterized in that: The meshing teeth are arc-shaped racks for accommodating the synchronous rollers, and the central angle of the meshing teeth is less than 180°. The opening size of the meshing teeth close to the first end is larger than the opening size close to the second end.

3. The assembly tool according to claim 2, characterized in that: The center angle of the meshing teeth is 10°~90°.

4. An assembly method based on the assembly tool according to any one of claims 1 to 3, characterized in that: A mechanical transmission device for assembling a variable compression ratio engine, the assembly method comprising the following steps: Assembling the combustion piston assembly, the control piston assembly and the transmission gear of the mechanical transmission device into the engine cylinder of the variable compression ratio engine, and making the transmission gear mesh with the combustion tooth plate of the combustion piston assembly and the control tooth plate of the control piston assembly at the same time; Connecting the positioning portion of the assembly tool to the engine cylinder body so that the first end of the assembly tool extends into the engine cylinder body; Moving the combustion piston assembly axially to a position where the combustion tooth plate abuts against the limiting step; Assembling the synchronous roller of the mechanical transmission device into the engine cylinder body so that the synchronous roller is engaged with the meshing teeth and the combustion tooth plate under the action of magnetic attraction; installing the synchronous tooth plate of the mechanical transmission device of the variable compression ratio engine onto the engine cylinder body so that the synchronous roller is engaged between the combustion tooth plate and the synchronous tooth plate; The assembly tool is removed, and the engine crankshaft is installed to complete the assembly of the mechanical transmission device of the variable compression ratio engine.

5. The assembly method according to claim 4, characterized in that: The step of axially moving the combustion piston assembly to a position where the combustion tooth plate abuts against the limiting step specifically includes: Position the control piston assembly and the transmission gear; under the action of a first pressing force F1 parallel to the axial direction of the combustion piston assembly, move the combustion piston assembly axially to the position where the combustion tooth plate abuts against the limiting step.

6. The assembly method according to claim 5, characterized in that: Before assembling the synchronous roller into the engine cylinder, the assembly method also includes, under the action of a second pressing force F2 having a component force perpendicular to the control tooth plate, transmitting the second pressing force F2 to the transmission gear to position the combustion tooth plate and the transmission gear.

7. The assembly method according to claim 6, characterized in that: The direction of application of the first pressing force F1 is perpendicular to the direction of application of the second pressing force F2.

8. The assembly method according to claim 7, characterized in that: The position where the combustion tooth plate abuts against the limiting step is set as the bottom dead center of the combustion piston assembly.

9. The assembly method according to claim 7, characterized in that: The first pressing force F1 is 5N-10N; the second pressing force F2 is 4N-6N.

10. The assembly method according to any one of claims 4 to 9, characterized in that: Assembling the combustion piston assembly, the control piston assembly and the transmission gear into the engine cylinder body specifically includes: Installing the combustion piston assembly into the engine cylinder body, meshing the control gear plate and the transmission gear, and installing the meshing transmission gear and the control gear plate into the engine cylinder body together, so that the transmission gear is meshed with the end of the combustion gear plate away from the combustion piston; The combustion piston assembly is axially moved toward the top dead center to a set installation position, and the control piston is installed on the control tooth plate to obtain the control piston assembly.

11. The assembly method according to any one of claims 4 to 9, characterized in that: Before installing the combustion piston assembly, the control piston, and the meshing control gear plate and the transmission gear into the engine cylinder body, the assembly method further includes: The engine cylinder block is placed in a posture where the combustion tooth plate is parallel to a horizontal plane and the synchronous roller is located on the upper side of the combustion tooth plate; The removing of the assembly tool and installing the engine crankshaft specifically includes removing the assembly tool, turning over the engine cylinder block so that the combustion gear plate is perpendicular to the horizontal plane, and installing the engine crankshaft.

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