Engine gear train and center distance positioning tool and assembly method thereof

Abstract

The application discloses an engine gear train and a center distance positioning tool and an assembling method thereof, and relates to the technical field of engines. The engine gear train is provided with an intermediate gear shaft positioning pin with adjustable position on an engine body, and dynamic adjustment compensation of the center distance can be realized. The gear train center distance positioning tool comprises a first positioning device and a second positioning device, and the two are rotationally matched with a connecting head through an arc-shaped connecting groove, so that the installation position of the intermediate gear shaft positioning pin can be accurately determined. The engine gear train assembling method comprises the steps of positioning through the gear train center distance positioning tool, rotationally adjusting, fixing the intermediate gear shaft positioning pin, installing gears and measuring side clearance, and the like, so that the gear side clearance of the final assembly can meet the design requirements. The application can accurately control the center distance of the gear pair, ensure that the gear side clearance meets the design requirements, improve the gear meshing quality, reduce the transmission noise, and improve the assembling efficiency and reliability.

Description

Technical Field

[0001] This invention relates to the field of engine technology, specifically to an engine gear system and its center distance positioning fixture and assembly method. Background Technology

[0002] In engine design, a compressible gasket is typically installed between the cylinder head and the engine block to seal the combustion chamber and prevent combustion gas leakage. To ensure the proper functioning of the gear transmission system, transmission gears are installed on both the cylinder head and the engine block; for example, one gear in a gear pair is mounted on the cylinder head, and the other gear is mounted on the engine block.

[0003] However, since the gasket is compressed after assembly, the amount of compression is affected by factors such as bolt preload, gasket material properties, and operating conditions, resulting in a certain degree of uncertainty. This compression causes a change in the relative position between the cylinder head and the engine block, which in turn causes the actual center distance between the gear mounted on the cylinder head and the gear mounted on the engine block to deviate from the design value, making precise control difficult.

[0004] Deviations in the center distance of gears directly affect the backlash of the gear pair. Insufficient backlash may lead to gear jamming, poor lubrication, or even transmission interference; excessive backlash may cause gear meshing impact, increased transmission noise, and accelerated tooth surface wear, and in severe cases, may lead to transmission failure.

[0005] Therefore, how to ensure that the center distance of the gear system mounted across the cylinder head and the engine block meets the design requirements in the presence of compressible gaskets is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned deficiencies in existing technologies, this invention provides an engine gear system, its center distance positioning fixture, and assembly method. This engine gear system and its center distance positioning fixture and assembly method achieve precise compensation and adjustment of the gear center distance, ensuring that the gear pair backlash meets design requirements, improving gear meshing quality, and enhancing the reliability of the gear transmission system.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] An engine gear system includes a cylinder head, an engine block, a first gear shaft, a first gear, an intermediate gear shaft, an intermediate gear, a second gear shaft, and a second gear. The cylinder head is mounted on the engine block, and a sealing gasket is provided between the cylinder head and the engine block. The cylinder head has a positioning hole for the first gear shaft, which is positioned through the positioning hole and fixed to the cylinder head by a first locking bolt. The first gear is rotatably mounted on the first gear shaft. The engine block has a positioning hole for the second gear shaft, which is positioned through the positioning hole and fixed to the engine block by a second locking bolt. The second gear is rotatably mounted on the second gear shaft. The engine block has an adjustable positioning pin for the intermediate gear shaft, which is positioned through the positioning pin and fixed to the engine block by a third locking bolt. The intermediate gear is rotatably mounted on the intermediate gear shaft and meshes with both the first gear and the second gear.

[0009] The intermediate gear shaft positioning pin is fixed to the machine body by a fourth locking bolt. The machine body is provided with a locking hole that cooperates with the fourth locking bolt. The intermediate gear shaft positioning pin has an adjustment hole that penetrates itself axially. The diameter of the adjustment hole is larger than the diameter of the fourth locking bolt. The fourth locking bolt passes through the adjustment hole and is threadedly connected to the locking hole.

[0010] The machine body is provided with a mounting hole for installing the intermediate gear shaft positioning pin. The depth of the mounting hole is less than the height of the intermediate gear shaft positioning pin, and the diameter of the mounting hole is greater than the diameter of the intermediate gear shaft positioning pin. The locking hole is opened at the bottom of the mounting hole.

[0011] The intermediate gear shaft is provided with a positioning hole on the intermediate gear shaft that is adapted to the positioning pin of the intermediate gear shaft, and the diameter of the positioning hole of the intermediate gear shaft is equal to the diameter of the positioning pin of the intermediate gear shaft.

[0012] A gear system center distance positioning fixture for assembling the aforementioned engine gear system includes a first positioning device, a first gear positioning pin, a second positioning device, and a second gear positioning pin. The first gear positioning pin is adapted to a first gear shaft positioning hole. The first positioning device has a first gear positioning hole adapted to the first gear positioning pin, and an arc-shaped connecting groove at its end. The axis of the first gear positioning hole is parallel to the axis of the connecting groove. The second gear positioning pin is adapted to the second gear shaft positioning hole. The second positioning device has a second gear positioning hole adapted to the second gear positioning pin, and an arc-shaped connector at its end. The connector has a coaxial intermediate gear positioning hole adapted to the intermediate gear shaft positioning pin, and the axis of the second gear positioning hole is parallel to the axis of the intermediate gear positioning hole. The connector is rotatably sleeved within the connecting groove, and the two are in transition fit.

[0013] The first positioning device includes a first positioning block, a first adjusting plate, and two first tightening bolts. The first positioning block has a first linear guide groove, and the first adjusting plate is slidably disposed in the first linear guide groove. The two first tightening bolts are symmetrically threaded onto the groove wall of the first linear guide groove and pass through the groove wall of the first linear guide groove to tighten the first adjusting plate to fix it. The first gear positioning hole is disposed on the first positioning block, and the connecting groove is disposed at the end of the first adjusting plate. The first adjusting plate also has a first elongated hole extending along its sliding direction, the first elongated hole corresponding to the position of the first gear positioning hole, and the width of the first elongated hole is greater than the diameter of the first gear positioning hole.

[0014] The first adjusting plate has a center distance adjustment scale line extending along its sliding direction. The zero mark of the center distance adjustment scale line is close to the connecting groove, and the vertical distance between the center of the connecting groove and the zero mark line is L1. The end face of the first positioning block near the connecting groove is a scale indicator surface, which is used to align with the center distance adjustment scale line to indicate the center distance adjustment value L2. The vertical distance between the center of the first gear positioning hole and the scale indicator surface is L3. The center distance La between the first gear and the intermediate gear is La = L1 + L2 + L3.

[0015] The second positioning device includes a second positioning block, a second adjusting plate, and two second tightening bolts. The second positioning block has a second linear guide groove, and the second adjusting plate is slidably disposed in the second linear guide groove. The two second tightening bolts are symmetrically threaded onto the groove wall of the second linear guide groove and pass through the groove wall of the second linear guide groove to tighten the second adjusting plate to fix it. The second gear positioning hole is disposed on the second positioning block, and the connector is disposed at the end of the second adjusting plate. The second adjusting plate also has a second elongated hole extending along its sliding direction, the second elongated hole corresponding to the position of the second gear positioning hole, and the width of the second elongated hole is greater than the diameter of the second gear positioning hole.

[0016] The second adjusting plate has a center distance adjustment scale line extending along its sliding direction. The zero mark of the center distance adjustment scale line is close to the connector. The vertical distance between the center of the connector and the zero mark is L4. The end face of the second positioning block near the connector is a scale indicator surface. The scale indicator surface is used to align with the center distance adjustment scale line to indicate the center distance adjustment value L5. The vertical distance between the center of the second gear positioning hole and the scale indicator surface is L6. The center distance between the second gear and the intermediate gear is Lb = L4 + L5 + L6.

[0017] An assembly method for an engine gear system, used to assemble the engine gear system described above, and employing the positioning fixture based on the center distance of the gear system described above, includes the following steps:

[0018] S1. The first positioning device is positioned on the cylinder head by the cooperation of the first gear positioning pin with the first gear positioning hole and the first gear shaft positioning hole.

[0019] S2. Rotate the connector of the second positioning device into the connecting groove of the first positioning device to form a rotating connection with a transition fit.

[0020] S3. The second positioning device is positioned on the machine body by the cooperation of the second gear positioning pin with the second gear positioning hole and the second gear shaft positioning hole;

[0021] S4. Using the second gear positioning pin as an axis, rotate the second positioning device to adjust the position of the intermediate gear positioning hole on the connector head, so that the intermediate gear positioning hole is aligned with the required installation position of the intermediate gear shaft positioning pin on the machine body, and then fix the intermediate gear shaft positioning pin on the machine body according to the position of the intermediate gear positioning hole.

[0022] S5. Remove the first gear positioning pin and the second gear positioning pin, and remove the first positioning device and the second positioning device;

[0023] S6. Rotate the intermediate gear onto the intermediate gear shaft, then position the intermediate gear shaft using the intermediate gear shaft positioning pin and fix it to the machine body using the third locking bolt;

[0024] S7. Rotate the first gear onto the first gear shaft, then position the first gear shaft through the first gear shaft positioning hole and fix it to the cylinder head with the first locking bolt.

[0025] S8. Rotate the second gear onto the second gear shaft, then position the second gear shaft through the second gear shaft positioning hole and fix it to the machine body with the help of the second locking bolt;

[0026] S9. Measure the backlash between the first gear and the intermediate gear, and between the intermediate gear and the second gear. If it is qualified, the assembly is completed; if it is not qualified, repeat steps S1 to S5 to adjust the position of the intermediate gear shaft positioning pin, and then execute S6 to S9 in sequence.

[0027] By adopting the above technical solution, the beneficial effects of the present invention are:

[0028] The engine gear system provided by this invention, by setting an adjustable intermediate gear shaft locating pin on the engine block, allows the installation position of the intermediate gear shaft to be dynamically adjusted according to the actual compression of the sealing gasket. This compensates for the center distance deviation caused by the change in the relative position of the cylinder head and the engine block, ensuring that the intermediate gear meshes precisely with the first gear and the second gear respectively. This ensures that the gear pair backlash meets the design requirements, effectively avoiding gear impact and increased noise caused by excessive center distance, or jamming and abnormal wear caused by excessive center distance. In this way, the reliability of the gear transmission system is improved, the service life is extended, and the transmission noise is reduced.

[0029] The gear train center distance positioning fixture provided by this invention uses a first positioning device to simulate the position of the first gear on the cylinder head and a second positioning device to simulate the position of the second gear on the engine block. The transition fit between the connector and the connecting groove allows the second positioning device to swing relative to the first positioning device, thereby accurately determining the ideal installation position of the intermediate gear shaft positioning pin in the intermediate gear positioning hole on the connector. This solves the problem of difficult direct measurement caused by the uncertainty of the gasket compression. Furthermore, this gear train center distance positioning fixture can flexibly adapt to different center distance deviations without requiring separate fixture design for each deviation. It is compact, easy to operate, and can quickly determine the installation position of the intermediate gear shaft positioning pin, significantly improving assembly efficiency and accuracy.

[0030] The engine gear system assembly method provided by this invention follows a standardized process of sequentially executing tooling positioning, rotation adjustment, intermediate gear shaft locating pin fixing, gear system component installation, and backlash measurement. Before installing the gear shaft and gears, the position of the intermediate gear shaft locating pin is precisely determined using tooling, avoiding costly rework due to center distance deviations. Furthermore, by measuring the backlash between the first gear and the intermediate gear, and between the intermediate gear and the second gear, and judging its compliance, if it fails, the tooling positioning and adjustment steps are repeated to ensure that the final assembled gear backlash meets design requirements. This guarantees gear meshing quality, reduces transmission noise, and the method is highly standardized and repeatable, making it suitable for engine mass assembly production lines. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the engine gear system in this invention;

[0032] Figure 2 yes Figure 1 Sectional view of AA;

[0033] Figure 3 yes Figure 2 Enlarged view of section E in the middle;

[0034] Figure 4 yes Figure 3 Another sectional view of the intermediate gear;

[0035] Figure 5 This is a schematic diagram of the gear system center distance positioning fixture in this invention;

[0036] Figure 6 yes Figure 5 Exploded view;

[0037] Figure 7 yes Figure 5 Sectional view of BB;

[0038] Figure 8 yes Figure 5 Sectional view of CC;

[0039] Figure 9 yes Figure 5 Usage status reference diagram;

[0040] Figure 10 yes Figure 9 Sectional view of DD;

[0041] Figure 11 yes Figure 10 Enlarged view of section F in the middle;

[0042] Figure 12This is a flowchart of the assembly method of the engine gear system in this invention;

[0043] In the diagram: 1. Cylinder head; 101. First gear shaft positioning hole; 2. Engine body; 201. Second gear shaft positioning hole; 202. Mounting hole; 203. Locking hole; 3. First gear shaft; 301. First gear shaft oil hole; 4. First gear; 5. Intermediate gear shaft; 501. Intermediate gear shaft positioning hole; 502. Intermediate gear shaft oil hole; 6. Intermediate gear; 7. Second gear shaft; 701. Second gear shaft oil hole; 8. Second gear; 9. First locking bolt; 10. Second locking bolt; 11. Third locking bolt; 12. Intermediate gear shaft positioning pin; 13. Fourth locking bolt; 14. Intermediate gear bushing; 15. Gear stop. Plate; 16. First gear bushing; 17. Second gear bushing; 18. First positioning block; 181. First gear positioning hole; 182. First linear guide groove; 19. First adjusting plate; 191. Connecting groove; 192. First elongated hole; 20. First tightening bolt; 21. First gear positioning pin; 22. Second positioning block; 221. Second gear positioning hole; 222. Second linear guide groove; 23. Second adjusting plate; 231. Connector; 232. Intermediate gear positioning hole; 233. Second elongated hole; 24. Second tightening bolt; 25. Second gear positioning pin; 26. Center distance adjustment scale line; 27. Scale indicator surface. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the drawings are schematic diagrams used to aid in understanding the invention; the specific embodiments described are merely illustrative and not intended to limit the scope of protection of the invention.

[0045] like Figures 1 to 12As shown, an engine gear system and its center distance positioning fixture and assembly method are provided. The engine gear system includes a cylinder head 1, an engine block 2, a first gear shaft 3, a first gear 4, an intermediate gear shaft 5, an intermediate gear 6, a second gear shaft 7, and a second gear 8. The cylinder head 1 is mounted on the engine block 2, and a sealing gasket (not shown) is provided between the cylinder head 1 and the engine block 2 to prevent combustion chamber leakage. The cylinder head 1 has a first gear shaft positioning hole 101. The first gear shaft 3 is positioned through the first gear shaft positioning hole 101 and fixed to the cylinder head 1 by means of a first locking bolt 9. A gear 4 is rotatably mounted on a first gear shaft 3; a second gear shaft positioning hole 201 is provided on the machine body 2, the second gear shaft 7 is positioned through the second gear shaft positioning hole 201 and fixed to the machine body 2 by means of a second locking bolt 10, and a second gear 8 is rotatably mounted on the second gear shaft 7; an adjustable intermediate gear shaft positioning pin 12 is provided on the machine body 2, the intermediate gear shaft 5 is positioned through the intermediate gear shaft positioning pin 12 and fixed to the machine body 2 by means of a third locking bolt 11, and an intermediate gear 6 is rotatably mounted on the intermediate gear shaft 5, and the intermediate gear 6 meshes with the first gear 4 and the second gear 8 respectively.

[0046] The engine gear system uses an adjustable intermediate gear shaft positioning pin 12 on the engine body 2 to adjust the installation position of the intermediate gear shaft 5 on the engine body 2 according to the actual compression of the sealing gasket. This compensates for the center distance deviation caused by the change in the relative position of the cylinder head 1 and the engine body 2 due to the compression of the sealing gasket, and ensures that the intermediate gear 6 meshes correctly with the first gear 4 and the second gear 8 respectively.

[0047] In this embodiment, the intermediate gear shaft positioning pin 12 is fixed to the machine body 2 by a fourth locking bolt 13. The machine body 2 is provided with a locking hole 203 that mates with the fourth locking bolt 13. The intermediate gear shaft positioning pin 12 has an adjustment hole that penetrates axially through itself. The diameter of the adjustment hole is larger than the diameter of the fourth locking bolt 13. The fourth locking bolt 13 passes through the adjustment hole and is threaded into the locking hole 203. By opening an adjustment hole with a diameter larger than that of the fourth locking bolt 13 on the intermediate gear shaft positioning pin 12, the intermediate gear shaft positioning pin 12 can move slightly relative to the fourth locking bolt 13 before locking, thereby realizing stepless adjustment of the position of the intermediate gear shaft positioning pin 12, improving adjustment accuracy and flexibility; at the same time, it has the advantage of simple structure, as only an adjustment hole needs to be drilled on the intermediate gear shaft positioning pin 12 to achieve position adjustment, resulting in low cost.

[0048] To facilitate quick installation of the intermediate gear shaft locating pin 12, this embodiment provides a mounting hole 202 on the machine body 2 for mounting the intermediate gear shaft locating pin 12. The depth H1 of the mounting hole 202 is less than the height H2 of the intermediate gear shaft locating pin 12, and the diameter D1 of the mounting hole 202 is greater than the diameter D2 of the intermediate gear shaft locating pin 12. A locking hole 203, threadedly connected to the fourth locking bolt 13, is located at the bottom of the mounting hole 202. The mounting hole 202, with a depth less than that of the intermediate gear shaft locating pin 12, allows the intermediate gear shaft locating pin 12 to protrude from the mounting hole 202, facilitating subsequent adjustment and disassembly. The diameter D1 of the mounting hole 202, being greater than the diameter D2 of the intermediate gear shaft locating pin 12, provides sufficient adjustment space for the intermediate gear shaft locating pin 12, avoiding interference. In this embodiment, D1 is preferably approximately 2 mm greater than D2. In practical applications, the values ​​of D1 and D2 can be set according to actual needs; this embodiment does not impose any limitations on this.

[0049] In this embodiment, the intermediate gear shaft 5 is coaxially provided with an intermediate gear shaft positioning hole 501 that matches the intermediate gear shaft positioning pin 12. The diameter of the intermediate gear shaft positioning hole 501 is equal to the diameter of the intermediate gear shaft positioning pin 12. The intermediate gear shaft 5 is positioned on the machine body 2 through the cooperation between the intermediate gear shaft positioning hole 501 and the intermediate gear shaft positioning pin 12. This arrangement ensures the coaxiality of the intermediate gear shaft 5 and the intermediate gear shaft positioning pin 12, further ensuring the accuracy of the gear center distance.

[0050] In this embodiment, a wear-resistant intermediate gear bushing 14 is provided on the intermediate gear shaft 5, and the intermediate gear 6 is installed on the intermediate gear bushing 14; the intermediate gear shaft 5 is also provided with an intermediate gear shaft oil hole 502, which connects the oil passage of the machine body 2 and the intermediate gear bushing 14. The machine oil enters the intermediate gear shaft oil hole 502 from the machine body 2 and flows through the intermediate gear shaft oil hole 502 to the intermediate gear bushing 14 to lubricate the intermediate gear 6.

[0051] Since the intermediate gear shaft 5 in this embodiment is a disc structure, a gear baffle 15 is added to limit the axial movement of the intermediate gear 6. After the intermediate gear 6 is installed on the intermediate gear shaft 5, the gear baffle 15 and the intermediate gear shaft 5 are fixed together on the machine body 2 by the third locking bolt 11.

[0052] In this embodiment, the first gear shaft 3 is a stepped shaft, comprising a first gear positioning section, a first gear mounting section, and a first gear limiting section connected in sequence. The first gear positioning section mates with the first gear shaft positioning hole 101, and the diameter of the first gear positioning section is equal to the diameter of the first gear shaft positioning hole 101. The first gear shaft 3 is positioned on the cylinder head 1 through the mating of the first gear positioning section and the first gear shaft positioning hole 101. This arrangement ensures the coaxiality of the first gear shaft 3 and the first gear shaft positioning hole 101, further ensuring the accuracy of the gear center distance. The first gear mounting section is provided with wear-resistant... The first gear bushing 16 is used to mount the first gear 4. The first gear limiting section is used to axially limit the mounted first gear 4. The first gear shaft 3 is also provided with a first gear shaft oil hole 301, which connects the oil passage of the cylinder head 1 and the first gear bushing 16. The engine oil enters the first gear shaft oil hole 301 from the cylinder head 1 and flows through the first gear shaft oil hole 301 to the first gear bushing 16 to lubricate the first gear 4. After the first gear 4 is mounted on the first gear shaft 3, the first gear shaft 3 is fixed to the cylinder head 1 by the first locking bolt 9.

[0053] In this embodiment, the second gear shaft 7 is a stepped shaft, comprising a second gear positioning section, a second gear mounting section, and a second gear limiting section connected sequentially. The second gear positioning section mates with the second gear shaft positioning hole 201, and the diameter of the second gear positioning section is equal to the diameter of the second gear shaft positioning hole 201. The second gear shaft 7 is positioned on the machine body 2 through the mating of the second gear positioning section and the second gear shaft positioning hole 201. This arrangement ensures the coaxiality of the second gear shaft 7 and the second gear shaft positioning hole 201, further ensuring the accuracy of the gear center distance. The second gear mounting section is provided with a wear-resistant... The second gear bushing 17 is used for grinding, and the second gear 8 is installed on the second gear bushing 17. The second gear limiting section is used to axially limit the installed second gear 8. The second gear shaft 7 is also provided with a second gear shaft oil hole 701, which connects the oil passage of the machine body 2 and the second gear bushing 17. The machine oil enters the second gear shaft oil hole 701 from the machine body 2 and flows to the second gear bushing 17 through the second gear shaft oil hole 701 to lubricate the second gear 8. After the second gear 8 is installed on the second gear shaft 7, the second gear shaft 7 is fixed to the machine body 2 by the second locking bolt 10.

[0054] The engine gear system with the above structure can dynamically compensate for center distance deviation, ensuring that the backlash of the gear pair meets the design requirements, improving the reliability and life of the gear transmission system, and reducing transmission noise.

[0055] The gear train center distance positioning fixture in this embodiment is used to assemble the engine gear train of the above structure. It includes a first positioning device, a first gear positioning pin 21, a second positioning device, and a second gear positioning pin 25. The first gear positioning pin 21 is adapted to the first gear shaft positioning hole 101. The first positioning device is provided with a first gear positioning hole 181 adapted to the first gear positioning pin 21. The end of the first positioning device is provided with an arc-shaped connecting groove 191. The axis of the first gear positioning hole 181 is parallel to the axis of the connecting groove 191. The second gear positioning pin 25 is adapted to the second gear shaft positioning hole 201. The second positioning device is provided with a second gear positioning hole 221 adapted to the second gear positioning pin 25. The end of the second positioning device is provided with an arc-shaped connector 231. The connector 231 is coaxially provided with an intermediate gear positioning hole 232 adapted to the intermediate gear shaft positioning pin 12. The axis of the second gear positioning hole 221 is parallel to the axis of the intermediate gear positioning hole 232. The connector 231 is rotatably sleeved in the connecting groove 191 and the two are transitionally fitted.

[0056] The aforementioned gear system center distance positioning fixture uses a first positioning device to simulate the position of the first gear 4 on the cylinder head 1 and a second positioning device to simulate the position of the second gear 8 on the machine body 2. It utilizes the transition fit between the connector 231 and the connecting groove 191 for rotational connection, allowing the second positioning device to swing relative to the first positioning device. This accurately determines the ideal installation position of the intermediate gear shaft positioning pin 12 in the intermediate gear positioning hole 232 on the connector 231, solving the problem of difficult direct measurement caused by the uncertainty of the gasket compression. Simultaneously, this gear system center distance positioning fixture can flexibly adapt to different center distance deviations, eliminating the need for separate fixture design for each deviation. Furthermore, its compact structure and convenient operation allow for rapid determination of the intermediate gear shaft positioning pin 12's installation position, significantly improving assembly efficiency and accuracy.

[0057] The first positioning device in this embodiment includes a first positioning block 18, a first adjusting plate 19, and two first tightening bolts 20. The first positioning block 18 is provided with a first linear guide groove 182, and the first adjusting plate 19 is slidably disposed in the first linear guide groove 182. The two first tightening bolts 20 are symmetrically threaded onto the groove wall of the first linear guide groove 182, and pass through the groove wall of the first linear guide groove 182 to tighten the first adjusting plate 19 to fix it. A first gear positioning hole 181 is provided on the first positioning block 18, and a connecting groove 191 is provided at the end of the first adjusting plate 19. The first adjusting plate 19 is also provided with a first elongated hole 192 extending along its sliding direction. The first elongated hole 192 corresponds to the position of the first gear positioning hole 181, and the width of the first elongated hole 192 is greater than the diameter of the first gear positioning hole 181. By sliding the first adjusting plate 19 to change the center distance between the connecting groove 191 and the first gear positioning hole 181, the design center distance between the first gear 4 and the intermediate gear 6 is precisely set; the two first tightening bolts 20 are symmetrically arranged to achieve uniform locking force and effectively prevent the first adjusting plate 19 from tilting; and the width of the first elongated hole 192 is greater than the diameter of the first gear positioning hole 181, which allows the first gear positioning pin 21 to move relative to each other in the first elongated hole 192, avoiding over-positioning, and at the same time providing sliding space for the first adjusting plate 19.

[0058] Preferably, the first adjusting plate 19 is provided with a center distance adjustment scale line 26 extending along its sliding direction. The zero mark of the center distance adjustment scale line 26 is close to the connecting groove 191, and the vertical distance between the center of the connecting groove 191 and the zero mark is L1. The end face of the first positioning block 18 near the connecting groove 191 is a scale indicator surface 27, which is used to align with the center distance adjustment scale line 26 to indicate the center distance adjustment value L2. The vertical distance between the center of the first gear positioning hole 181 and the scale indicator surface 27 is L3. The center distance La between the first gear 4 and the intermediate gear 6 is La = L1 + L2 + L3. Through the center distance adjustment scale line 26 and the scale indicator surface 27, the operator can directly read the adjustment value L2 and quickly calculate the actual center distance La using the formula La = L1 + L2 + L3, thereby achieving quantitative adjustment and improving assembly efficiency and consistency.

[0059] The second positioning device in this embodiment includes a second positioning block 22, a second adjusting plate 23, and two second tightening bolts 24. The second positioning block 22 is provided with a second linear guide groove 222, and the second adjusting plate 23 is slidably disposed in the second linear guide groove 222. The two second tightening bolts 24 are symmetrically threaded onto the groove wall of the second linear guide groove 222, and pass through the groove wall of the second linear guide groove 222 to tighten the second adjusting plate 23 to fix it. A second gear positioning hole 221 is provided on the second positioning block 22, and a connector 231 is provided at the end of the second adjusting plate 23. The second adjusting plate 23 is also provided with a second elongated hole 233 extending along its sliding direction. The second elongated hole 233 corresponds to the position of the second gear positioning hole 221, and the width of the second elongated hole 233 is greater than the diameter of the second gear positioning hole 221. By sliding the second adjusting plate 23 to change the center distance between the connector 231 and the second gear positioning hole 221, the design center distance between the second gear 8 and the intermediate gear 6 is precisely set; the two second tightening bolts 24 are symmetrically arranged to achieve uniform locking force and effectively prevent the second adjusting plate 23 from tilting; and the width of the second elongated hole 233 is greater than the diameter of the second gear positioning hole 221, which allows the second gear positioning pin 25 to move relative to each other in the second elongated hole 233, avoiding over-positioning, and at the same time providing sliding space for the second adjusting plate 23.

[0060] Preferably, the second adjusting plate 23 is also provided with a center distance adjustment scale line 26 extending along its sliding direction. The zero mark of the center distance adjustment scale line 26 is close to the connector 231, and the vertical distance between the center of the connector 231 and the zero mark is L4. The end face of the second positioning block 22 near the connector 231 is a scale indicator surface 27, which is used to align with the center distance adjustment scale line 26 to indicate the center distance adjustment value L5. The vertical distance between the center of the second gear positioning hole 221 and the scale indicator surface 27 is L6. The center distance Lb between the second gear 8 and the intermediate gear 6 is L4 + L5 + L6. Through the center distance adjustment scale line 26 and the scale indicator surface 27, the operator can directly read the adjustment value L5 and quickly calculate the actual center distance Lb using the formula Lb = L4 + L5 + L6, achieving quantitative adjustment and improving assembly efficiency and consistency.

[0061] In this embodiment, the first positioning device and the second positioning device can be adjusted independently without interfering with each other, thus satisfying the different deviation requirements of the side where the first gear 4 is located and the side where the second gear 8 is located in the above-mentioned engine gear system.

[0062] The engine gear system assembly method provided in this embodiment is used to assemble the aforementioned engine gear system and to locate the gear system center distance using the aforementioned gear system center distance positioning fixture, including the following steps:

[0063] S1. The first positioning device is positioned on the cylinder head 1 by the cooperation of the first gear positioning pin 21 with the first gear positioning hole 181 and the first gear shaft positioning hole 101. Specifically, the first gear positioning hole 181 of the first positioning device of the gear train center distance positioning fixture is aligned with the first gear shaft positioning hole 101, and then the first gear positioning pin 21 is inserted into the first gear shaft positioning hole 101 through the first gear positioning hole 181, thereby positioning one end of the first positioning device on the cylinder head 1.

[0064] S2. Rotate the connector 231 of the second positioning device into the connecting groove 191 of the first positioning device to form a rotating connection with transition fit between the two.

[0065] S3. By cooperating with the second gear positioning pin 25 and the second gear positioning hole 221 and the second gear shaft positioning hole 201, the second positioning device is positioned on the machine body 2. Specifically, the second gear positioning hole 221 of the second positioning device of the gear system center distance positioning fixture is aligned with the second gear shaft positioning hole 201, and then the second gear positioning pin 25 is inserted into the second gear shaft positioning hole 201 through the second gear positioning hole 221, thereby positioning one end of the second positioning device on the machine body 2.

[0066] S4. Using the second gear positioning pin 25 as the axis, rotate the second positioning device to adjust the position of the intermediate gear positioning hole 232 on the connector 231 so that the intermediate gear positioning hole 232 is aligned with the required installation position of the intermediate gear shaft positioning pin 12 on the machine body 2. Then, according to the position of the intermediate gear positioning hole 232, fix the intermediate gear shaft positioning pin 12 on the machine body 2.

[0067] S5. Remove the first gear positioning pin 21 and the second gear positioning pin 25, and remove the first positioning device and the second positioning device;

[0068] S6. Rotate the intermediate gear 6 onto the intermediate gear shaft 5, then position the intermediate gear shaft 5 using the intermediate gear shaft positioning pin 12 and fix it to the machine body 2 using the third locking bolt 11; specifically, install the intermediate gear bushing 14 onto the intermediate gear shaft 5, then rotate the intermediate gear 6 onto the intermediate gear bushing 14, then position the intermediate gear shaft 5 using the intermediate gear shaft positioning pin 12, and then fix the intermediate gear shaft 5 and the gear baffle 15 together to the machine body 2 using the third locking bolt 11;

[0069] S7. Rotate the first gear 4 onto the first gear shaft 3, then position the first gear shaft 3 through the first gear shaft positioning hole 101 and fix it onto the cylinder head 1 with the first locking bolt 9; specifically, install the first gear bushing 16 onto the first gear shaft 3, then rotate the first gear 4 onto the first gear bushing 16, then position the first gear shaft 3 through the first gear shaft positioning hole 101, and then fix the first gear shaft 3 onto the cylinder head 1 with the first locking bolt 9;

[0070] S8. Rotate the second gear 8 onto the second gear shaft 7, then position the second gear shaft 7 through the second gear shaft positioning hole 201 and fix it onto the machine body 2 with the help of the second locking bolt 10; specifically, install the second gear bushing 17 onto the second gear shaft 7, then rotate the second gear 8 onto the second gear bushing 17, then position the second gear shaft 7 through the second gear shaft positioning hole 201, and then fix the second gear shaft 7 onto the machine body 2 with the second locking bolt 10.

[0071] S9. Measure the backlash between the first gear 4 and the intermediate gear 6, and between the intermediate gear 6 and the second gear 8. If it is qualified, the assembly is completed; if it is not qualified, repeat steps S1 to S5 to adjust the position of the intermediate gear shaft positioning pin 12, and then execute S6 to S9 in sequence to make it meet the design requirements.

[0072] The assembly method for this engine gear system follows a standardized process of sequentially executing tooling positioning, rotation adjustment, fixing of the intermediate gear shaft locating pin 12, gear system component installation, and backlash measurement. Before installing the gear shaft and gears, the position of the intermediate gear shaft locating pin 12 is precisely determined using tooling, avoiding cost waste due to rework caused by center distance deviation. Furthermore, by measuring the backlash between the first gear 4 and the intermediate gear 6, and between the intermediate gear 6 and the second gear 8, and judging its compliance, if it is unqualified, the tooling positioning and adjustment steps are repeated to ensure that the backlash of the finally assembled gears meets the design requirements, thereby ensuring gear meshing quality and reducing transmission noise. Moreover, this method has a high degree of standardization and good repeatability, making it suitable for engine mass assembly production lines.

[0073] The embodiments of the engine gear system and its center distance positioning fixture and assembly method of the present invention have been described in detail above. Many other embodiments are also described but will not be elaborated upon here. It can be seen that the present invention achieves precise compensation and adjustment of the gear center distance, ensures that the gear pair backlash meets design requirements, improves gear meshing quality, and enhances the reliability of the gear transmission system.

[0074] This invention is not limited to the specific embodiments described above. Any modifications made by those skilled in the art based on the above concept without creative effort are within the scope of protection of this invention.

Claims

1. An engine gear system, comprising a cylinder head (1), an engine block (2), a first gear shaft (3), a first gear (4), an intermediate gear shaft (5), an intermediate gear (6), a second gear shaft (7), and a second gear (8), wherein the cylinder head (1) is mounted on the engine block (2), and a sealing gasket is provided between the cylinder head (1) and the engine block (2), characterized in that, The cylinder head (1) is provided with a first gear shaft positioning hole (101). The first gear shaft (3) is positioned through the first gear shaft positioning hole (101) and fixed to the cylinder head (1) by means of the first locking bolt (9). The first gear (4) is rotatably mounted on the first gear shaft (3). The body (2) is provided with a second gear shaft positioning hole (201). The second gear shaft (7) is positioned through the second gear shaft positioning hole (201) and fixed to the body (2) by means of the second locking bolt (10). The second gear (8) is rotatably mounted on the second gear shaft (7). The machine body (2) is provided with an adjustable intermediate gear shaft positioning pin (12). The intermediate gear shaft (5) is positioned by the intermediate gear shaft positioning pin (12) and fixed to the machine body (2) by means of a third locking bolt (11). The intermediate gear (6) is rotatably mounted on the intermediate gear shaft (5) and the intermediate gear (6) meshes with the first gear (4) and the second gear (8) respectively.

2. The engine gear train of claim 1, wherein, The intermediate gear shaft positioning pin (12) is fixed to the machine body (2) by the fourth locking bolt (13). The machine body (2) is provided with a locking hole (203) that cooperates with the fourth locking bolt (13). The intermediate gear shaft positioning pin (12) has an adjustment hole that penetrates itself axially. The diameter of the adjustment hole is larger than the diameter of the fourth locking bolt (13). The fourth locking bolt (13) passes through the adjustment hole and is threadedly connected to the locking hole (203).

3. The engine gear train of claim 2, wherein, The body (2) is provided with a mounting hole (202) for mounting the intermediate gear shaft positioning pin (12). The depth of the mounting hole (202) is less than the height of the intermediate gear shaft positioning pin (12), and the diameter of the mounting hole (202) is greater than the diameter of the intermediate gear shaft positioning pin (12). The locking hole (203) is opened at the bottom of the mounting hole (202).

4. The engine gear train of claim 1, wherein, The intermediate gear shaft (5) is provided with an intermediate gear shaft positioning hole (501) that is adapted to the intermediate gear shaft positioning pin (12) on the same axis. The diameter of the intermediate gear shaft positioning hole (501) is equal to the diameter of the intermediate gear shaft positioning pin (12).

5. A gear system center distance positioning fixture, used for assembling the engine gear system according to any one of claims 1 to 4, characterized in that, It includes a first positioning device, a first gear positioning pin (21), a second positioning device, and a second gear positioning pin (25); The first gear positioning pin (21) is adapted to the first gear shaft positioning hole (101); the first positioning device is provided with a first gear positioning hole (181) adapted to the first gear positioning pin (21), and the end of the first positioning device is provided with an arc-shaped connecting groove (191). The axis of the first gear positioning hole (181) is parallel to the axis of the connecting groove (191). The second gear positioning pin (25) is adapted to the second gear shaft positioning hole (201); the second positioning device is provided with a second gear positioning hole (221) adapted to the second gear positioning pin (25), and the end of the second positioning device is provided with an arc-shaped connector (231). The connector (231) is coaxially provided with an intermediate gear positioning hole (232) adapted to the intermediate gear shaft positioning pin (12). The axis of the second gear positioning hole (221) is parallel to the axis of the intermediate gear positioning hole (232). The connector (231) is rotatably sleeved in the connecting groove (191) and the two are transitionally fitted.

6. The gear train center distance positioning fixture according to claim 5, characterized in that, The first positioning device includes a first positioning block (18), a first adjusting plate (19), and two first tightening bolts (20); The first positioning block (18) is provided with a first linear guide groove (182), and the first adjusting plate (19) is slidably disposed in the first linear guide groove (182); the two first tightening bolts (20) are symmetrically threaded to the groove wall of the first linear guide groove (182), and pass through the groove wall of the first linear guide groove (182) to tighten the first adjusting plate (19) to fix it; The first gear positioning hole (181) is provided on the first positioning block (18), and the connecting groove (191) is provided at the end of the first adjusting plate (19); the first adjusting plate (19) is also provided with a first elongated hole (192) extending along its sliding direction, the first elongated hole (192) corresponds to the position of the first gear positioning hole (181), and the width of the first elongated hole (192) is greater than the diameter of the first gear positioning hole (181).

7. The gear train center distance positioning fixture according to claim 6, characterized in that, The first adjusting plate (19) is provided with a center distance adjustment scale line (26) extending along its sliding direction. The zero scale line of the center distance adjustment scale line (26) is close to the connecting groove (191). The vertical distance between the center of the connecting groove (191) and the zero scale line is L1. The end face of the first positioning block (18) close to the connecting groove (191) is a scale indicator surface (27). The scale indicator surface (27) is used to align with the center distance adjustment scale line (26) to indicate the center distance adjustment value L2. The vertical distance between the center of the first gear positioning hole (181) and the scale indicator surface (27) is L3. The center distance La between the first gear (4) and the intermediate gear (6) is La = L1 + L2 + L3.

8. The gear train center distance positioning fixture according to claim 5, characterized in that, The second positioning device includes a second positioning block (22), a second adjusting plate (23), and two second tightening bolts (24); The second positioning block (22) is provided with a second linear guide groove (222), and the second adjusting plate (23) is slidably disposed in the second linear guide groove (222); the two second tightening bolts (24) are symmetrically threaded to the groove wall of the second linear guide groove (222), and pass through the groove wall of the second linear guide groove (222) to tighten the second adjusting plate (23) to fix it; The second gear positioning hole (221) is provided on the second positioning block (22), and the connector (231) is provided at the end of the second adjusting plate (23); the second adjusting plate (23) is also provided with a second elongated hole (233) extending along its sliding direction, the second elongated hole (233) corresponds to the position of the second gear positioning hole (221), and the width of the second elongated hole (233) is greater than the diameter of the second gear positioning hole (221).

9. The gear train center distance positioning fixture according to claim 8, characterized in that, The second adjusting plate (23) is provided with a center distance adjustment scale line (26) extending along its sliding direction. The zero scale line of the center distance adjustment scale line (26) is close to the connector (231). The vertical distance between the center of the connector (231) and the zero scale line is L4. The end face of the second positioning block (22) close to the connector (231) is a scale indicator surface (27). The scale indicator surface (27) is used to align with the center distance adjustment scale line (26) to indicate the center distance adjustment value L5. The vertical distance between the center of the second gear positioning hole (221) and the scale indicator surface (27) is L6. The center distance between the second gear (8) and the intermediate gear (6) is Lb = L4 + L5 + L6.

10. A method for assembling an engine gear train, used for assembling the engine gear train according to any one of claims 1 to 4, and employing a gear train center distance positioning fixture according to any one of claims 5 to 9, characterized in that, Includes the following steps: S1. By cooperating with the first gear positioning pin (21) and the first gear positioning hole (181) and the first gear shaft positioning hole (101), the first positioning device is positioned on the cylinder head (1); S2. Rotate the connector (231) of the second positioning device into the connecting groove (191) of the first positioning device to form a rotating connection with transition fit. S3. By cooperating with the second gear positioning pin (25) and the second gear positioning hole (221) and the second gear shaft positioning hole (201), the second positioning device is positioned on the machine body (2); S4. Using the second gear positioning pin (25) as the axis, rotate the second positioning device to adjust the position of the intermediate gear positioning hole (232) on the connector (231) so that the intermediate gear positioning hole (232) is aligned with the required installation position of the intermediate gear shaft positioning pin (12) on the machine body (2). Then, according to the position of the intermediate gear positioning hole (232), fix the intermediate gear shaft positioning pin (12) on the machine body (2). S5. Remove the first gear positioning pin (21) and the second gear positioning pin (25), and remove the first positioning device and the second positioning device; S6. Rotate the intermediate gear (6) onto the intermediate gear shaft (5), then position the intermediate gear shaft (5) by the intermediate gear shaft positioning pin (12) and fix it to the machine body (2) by means of the third locking bolt (11); S7. Rotate the first gear (4) onto the first gear shaft (3), then position the first gear shaft (3) through the first gear shaft positioning hole (101) and fix it onto the cylinder head (1) with the first locking bolt (9); S8. Rotate the second gear (8) onto the second gear shaft (7), then position the second gear shaft (7) through the second gear shaft positioning hole (201) and fix it onto the machine body (2) with the help of the second locking bolt (10); S9. Measure the backlash between the first gear (4) and the intermediate gear (6), and between the intermediate gear (6) and the second gear (8). If it is qualified, the assembly is completed; if it is not qualified, repeat steps S1 to S5 to adjust the position of the intermediate gear shaft positioning pin (12), and then execute S6 to S9 in sequence.

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