A method of assembling a shift lever and a fork

Abstract

The application discloses a kind of gear lever and shift fork assembly methods, belong to new energy automobile transmission assembly technical field.The method includes the following steps: preparation end circle processing annular groove gear lever and shift fork;Shift fork is positioned on lifting plate, shift fork is driven downward by lifting device, make induction heating coil extend into the assembly hole of shift fork, and the assembly hole is heated using induction heating mode to expand;After heating, lifting device drives shift fork to rise, and gear lever end is inserted into the assembly hole of shift fork;Cooling shift fork makes assembly hole shrink, and gear lever is fixed in shift fork hole.The present application uses induction heating to realize hot assembly interference fit, simplifies production steps, and the annular groove on gear lever can make shift fork material plastic insert during hot jacketing, greatly increase friction and torsional capacity, effectively prevent rotation and slip, with high assembly efficiency, low machining precision requirement, especially suitable for mass production of new energy automobile transmission.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle transmission assembly technology, and in particular to a method for assembling a shift lever and a shift fork. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the requirements for assembly efficiency and precision of core transmission components are increasing. The shift fork is a key component in the transmission of new energy vehicles, its main function being to shift gears by moving it. The shift lever is connected to the shift fork; when the shift fork is moved, the control hydraulic valve on the shift lever generates a corresponding linkage to achieve different operational requirements.

[0003] Currently, the connection between the shift fork and the gear shift lever mainly adopts a transition fit method. The assembly process typically includes the following steps: drilling and reaming the shift fork → turning the outer diameter of the gear shift lever → grinding the outer diameter of the gear shift lever → pressing the end of the gear shift lever into the shift fork hole → machining a pin hole in a machining center → pressing the pin into the pin hole → welding the pin to prevent it from falling out. However, this traditional assembly method has many drawbacks: First, the processing flow is long, requiring seven steps to complete the assembly, resulting in low production efficiency and making it difficult to meet the demands of the new energy vehicle industry for large-scale, high-efficiency production. Second, the fit precision requirements between the gear shift lever and the shift fork are extremely high. The assembly hole for the shift fork is usually drilled and reamed, and the currently stable dimensional accuracy is only +0.02mm. To ensure assembly quality, the dimensions of the gear shift lever must be within ±0.01mm. If the shift lever is too large (interference exceeding 0.01mm), it becomes very difficult to press into the shift fork hole, and may even bend before it can be installed. If the clearance is greater than 0.02mm, the shift lever and shift fork will be too loosely assembled, and the shift fork may fall off during subsequent pin drilling, or loosen during use, causing inaccurate shifting and seriously affecting the driving safety of new energy vehicles. Furthermore, because part of the outer diameter of the shift lever needs to mate with the shift cylinder, there is a sealing requirement, requiring a surface roughness of Ra0.2. However, during the processes of drilling pin holes, pressing pins, and welding pins after press-fitting, the outer diameter of the shift lever is very easily damaged, leading to seal failure and scrapping, increasing the manufacturing cost of new energy vehicle transmissions. The precision requirements for drilling pin holes are also very high, generally within (0, +0.015)mm. If the pin hole is too small, the pin cannot be pressed in, and may deform and become unusable after only being pressed in halfway; if the pin hole is too large, the pin is prone to falling out. Existing assembly methods are inefficient, difficult to process and assemble, require high technical control, and are prone to producing defective products, resulting in a high scrap rate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned shortcomings of the prior art by providing a method for assembling a shift lever and a shift fork, which can quickly and firmly assemble the shift lever onto the shift fork, effectively improving assembly efficiency and quality, and is characterized by ease of use and strong practicality.

[0005] The technical solution adopted in this invention is: a method for assembling a gear shift lever and a shift fork, comprising the following steps: S1: Prepare a shift lever and a shift fork, wherein the outer circumference of the end of the shift lever is machined with an annular groove; S2: Start the water pump and turn on the cooling. Control the lifting plate to the upper position using the cylinder control handle and place the shift fork on the lifting plate. S3: The lifting plate with the shift fork is controlled to move downward to the lower position by the cylinder operating handle. The induction heating coil is in the shift fork hole, and the assembly hole of the shift fork is heated by induction heating. S4: Heating is finished. Control the lifting plate and shift fork to move upward to the upper position by operating the cylinder handle. The induction heating coil leaves the shift fork hole. At this time, because the shift fork is heated, the shift fork hole expands due to heating. Quickly insert the end of the shift lever into the shift fork hole and hold for 5 seconds. S5: Cool the shift fork to shrink the mounting hole of the shift fork, and fix the shift lever in the mounting hole of the shift fork. The assembly is now complete.

[0006] As a further improvement, the annular groove has a groove width of 1.5 mm, a pitch of 15 mm, a machining length of 30 mm, and a machining depth of 0.2 mm.

[0007] Furthermore, the end of the shift lever and the mounting hole of the shift fork are interference fit, and the interference between the end of the shift lever and the mounting hole of the shift fork is 0.04mm to 0.09mm.

[0008] Furthermore, the induction heating is implemented through an induction heating coil, which is located below the heating position of the mounting hole of the shift fork. When the lifting device drives the shift fork to move downward, the mounting hole of the shift fork is sleeved outside the induction heating coil.

[0009] Furthermore, the lifting device includes a back plate, a linear guide rail, a sliding plate, and a cylinder. The back plate is mounted on a frame, the linear guide rail and the cylinder are mounted on the back plate, and the sliding plate is mounted on the slider of the linear guide rail. One end of the sliding plate is connected to the output end of the cylinder, and the other end is connected to a lifting plate for placing the shift fork.

[0010] Furthermore, the lifting plate is provided with a clearance hole. In step S3, when the lifting device drives the shift fork to move downward, the induction heating coil passes through the clearance hole and extends into the assembly hole of the shift fork.

[0011] Furthermore, the lifting plate is provided with a positioning plate and a positioning pin, and the shift fork in step S1 is positioned on the lifting plate by the positioning plate and the positioning pin.

[0012] Furthermore, during the induction heating process, the induction heating coil is cooled by a cooling device, which includes a cooling pool, a water pump, an inlet pipe, and an outlet pipe. One end of the inlet pipe is connected to the cooling pool, and the other end is connected to one end of the induction heating coil. One end of the outlet pipe is connected to the other end of the induction heating coil, and the other end is connected to the cooling pool. The water pump is installed on the inlet pipe.

[0013] Furthermore, the shift fork is made of forged 45 steel with a hardness of 180-220 HB; the shift lever is made of tempered material with a hardness of 30-35 HRC.

[0014] Furthermore, the mounting hole of the shift fork is formed by drilling and reaming, with a dimensional accuracy of +0.02mm.

[0015] Beneficial effects Compared with the prior art, the present invention has the following advantages: 1. This invention significantly simplifies the processing flow. Traditional methods require seven steps, while this invention only requires four (drilling and reaming the shift fork → turning the outer diameter of the shift lever → grinding the outer diameter of the shift lever → heat-installing the end of the shift lever into the shift fork hole), which significantly improves production efficiency, effectively reduces the risk of damage during processing, and meets the needs of the new energy vehicle industry for large-scale, high-efficiency production of core components.

[0016] 2. This invention innovatively incorporates an annular groove on the shift lever. The annular groove is simple to machine, requiring only approximately 2 seconds on a lathe. Since the shift fork is made of forged 45 steel (hardness 180-220 HB) and the shift lever is made of tempered material (hardness 30-35 HRC), during the heat-fitting interference fit, the softer 45 steel shift fork preferentially undergoes plastic deformation, with some material protruding into the annular groove of the shift lever, thus significantly increasing friction. Comparative tests show that the shift lever with the annular groove exhibits 1 / 3 more radial and axial friction than one without, effectively preventing rotation and slippage between the shift fork and shift lever during use, thus meeting the stress requirements of new energy vehicle transmissions.

[0017] 3. This invention reduces the machining accuracy requirements. The fit tolerance between the shift lever and the shift fork hole is widened from ±0.01mm to (+0.04, +0.09)mm, and the tolerance range is expanded from 0.02mm to 0.05mm. This significantly reduces machining difficulty, tool wear, and greatly improves the pass rate, effectively reducing the manufacturing cost of new energy vehicle transmissions.

[0018] 4. This invention can be widely applied to transmission assembly lines for new energy vehicles (including pure electric vehicles, hybrid vehicles, etc.), which helps to improve the manufacturing level of core components of new energy vehicles and promote the high-quality development of the new energy vehicle industry.

[0019] 5. This invention employs induction heating to locally heat the assembly hole of the shift fork. This method offers rapid heating and high efficiency, concentrating heat on the assembly hole area requiring expansion while keeping other parts of the workpiece at a low temperature and minimizing thermal deformation, thus ensuring assembly quality. Simultaneously, a cooling system provides circulating water cooling to the induction heating coil, guaranteeing the stability and lifespan of the equipment during continuous operation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is an enlarged schematic diagram of the gear shift lever in this invention; Figure 3 This is a schematic diagram of the structure of the present invention in actual application; Figure 4 This is a schematic diagram of the assembly of the shift lever and shift fork of the present invention; Figure 5 This is an enlarged schematic diagram of the cooling device in this invention.

[0021] Among them: 1-stand, 2-heating device, 21-induction heater, 22-induction heating coil, 3-lifting device, 31-linear guide rail, 32-back plate, 33-cylinder, 34-sliding plate, 4-cooling device, 41-water pump, 42-inlet pipe, 43-outlet pipe, 5-cooling pool, 6-shift fork, 7-assembly hole, 8-lifting plate, 9-leaving hole, 10-positioning plate, 11-positioning pin, 12-cylinder operating handle, 13-annular groove, 20-shift lever. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments shown in the accompanying drawings.

[0023] See Figure 1-5 As shown, the assembly method of the shift lever and shift fork of the present invention includes the following steps: S1: Prepare shift lever 20 and shift fork 6. The outer circle of the end of shift lever 20 is machined with an annular groove 13. S2: Start the water pump 41 to turn on the cooling. Control the lifting plate 8 to the upper position through the cylinder operating handle 12 and place the shift fork 6 on the lifting plate 8. S3: The lifting plate 8 with the shift fork 6 is controlled to move downward to the lower position by the cylinder operating handle 12. The induction heating coil 22 is in the hole of the shift fork 6, and the assembly hole of the shift fork 6 is heated by induction heating. S4: Heating is finished. Control the lifting plate 8 with the shift fork 6 to move upward to the upper position by the cylinder operating handle 12. The induction heating coil 22 leaves the shift fork hole. At this time, because the shift fork 6 is heated, the shift fork hole expands due to heating. Quickly insert the end of the shift lever 20 into the hole of the shift fork 6 and hold for 5 seconds. S5: Cooling the shift fork 6 causes the mounting hole of the shift fork 6 to shrink, fixing the shift lever 20 into the mounting hole of the shift fork 6, thus completing the assembly.

[0024] In this embodiment, the water pump 41 of the cooling device 4 is first started to activate the cooling circulation, allowing cooling water to circulate between the cooling pool 5 and the induction heating coil 22. The cylinder 33 is extended and retracted by the cylinder operating handle 12, positioning the lifting plate 8 at the upper end. The shift fork 6 is placed on the lifting plate 8, and the shift fork 6 is positioned correctly by the positioning plate 10 and positioning pin 11. Then, the cylinder operating handle 12 controls the lifting plate 8 to move the shift fork 6 downwards to the lower end position. At this time, the induction heating coil 22 passes through the clearance hole 9 on the lifting plate 8 and is positioned within the mounting hole 7 of the shift fork 6. The induction heating machine 21 is started, and the induction heating coil 22 induction heats the mounting hole 7 of the shift fork 6. During the induction heating process, the alternating magnetic field generated by the induction heating coil 22 acts on the inner wall of the mounting hole 7 of the shift fork 6, forming eddy currents inside the metal. When the eddy currents flow through the metal resistance, Joule heating is generated, causing the inner wall of the mounting hole 7 to heat up rapidly, and the mounting hole 7 expands due to the heat. During the heating process, the cooling device 4 continuously cools the induction heating coil 22. Immediately after heating is complete, the lifting plate 8 is controlled by the cylinder operating handle 12 to move the shift fork 6 upwards to the upper position, and the induction heating coil 22 moves away from the mounting hole 7. At this time, because the mounting hole 7 of the shift fork 6 has been heated and expanded, the operator quickly inserts the end of the shift lever 20 into the mounting hole 7 of the shift fork 6. Figure 4 As shown. After about 5 seconds, the mounting hole 7 of the shift fork 6 shrinks due to cooling, and the shift lever 20 is then firmly fixed in the mounting hole 7 of the shift fork 6. Finally, remove the assembled shift fork 6 and shift lever 20 assembly from the device, thus completing the assembly. Repeating this process will enable mass production.

[0025] During the hot-fitting interference fit process, since the material of the shift fork 6 is a relatively soft forged 45 steel with a hardness of 180-220HB, and the material of the shift lever 20 is a relatively hard tempered material with a hardness of 30-35HRC, the inner wall of the mounting hole 7 of the shift fork 6 will preferentially undergo plastic deformation, and part of the material will be embedded into the annular groove 13 of the shift lever 20. This significantly increases the radial and axial friction between the shift lever 20 and the shift fork 6, effectively preventing relative rotation and axial slippage between the two during use.

[0026] The assembly method of this invention achieves a heat-fit interference fit between the shift fork and the shift lever through induction heating, replacing the traditional cold pressing and pin fixing methods. This significantly simplifies the assembly process, reducing it from seven steps to four, and lowers the machining accuracy requirements, allowing the tolerance to be relaxed from ±0.01mm to +0.04 to +0.09mm. It effectively prevents damage to the sealing surface of the shift lever during assembly, improves assembly efficiency and product qualification rate, and is especially suitable for the mass production of new energy vehicle transmissions, thus having high practical value.

[0027] Specifically, the annular groove 13 has a groove width of 1.5mm, a pitch of 15mm, a machining length of 30mm, and a machining depth of 0.2mm. The dimensions of the annular groove, with a groove width of 1.5mm and a machining depth of 0.2mm, ensure sufficient embedding space to accommodate the plastic deformation protrusion of the shift fork material without excessively weakening the mechanical strength of the shift lever. The design of the 15mm pitch and 30mm machining length ensures that the annular groove is distributed within the axial length range of the end of the shift lever and the mounting hole of the shift fork, so that the embedding effect covers the entire mating area. The setting of the annular groove greatly increases the radial and axial friction between the shift lever 20 and the shift fork 6.

[0028] Preferably, the end of the shift lever 20 and the mounting hole 7 of the shift fork 6 are interference-fitted. The interference amount between the end of the shift lever 20 and the mounting hole 7 of the shift fork 6 is 0.04mm to 0.09mm. During the induction heating process in step S3, the mounting hole of the shift fork 6 expands due to heat, and the hole diameter temporarily increases, allowing the interference fit that could not be achieved at room temperature to be successfully realized. The actual size of the mounting hole after heating is larger than the outer diameter of the end of the shift lever, and the shift lever can be easily inserted. During the cooling process in step S5, the temperature of the mounting hole of the shift fork 6 decreases, and the hole diameter returns to the room temperature size. At this time, the interference fit of 0.04mm to 0.09mm is established, and the shift lever is firmly fixed in the mounting hole of the shift fork. The interference range of 0.04mm to 0.09mm is significantly widened compared to the ±0.01mm tolerance requirement of the traditional method. The tolerance range is increased from 0.02mm to 0.05mm, which significantly reduces the machining accuracy requirements of the outer diameter of the shift lever, and reduces machining costs and tool wear.

[0029] Furthermore, induction heating is implemented through an induction heating coil 22, which is positioned below the heating position of the mounting hole 7 of the shift fork 6. When the lifting device 3 moves the shift fork 6 downward, the mounting hole 7 of the shift fork 6 is fitted over the induction heating coil 22. This structural arrangement allows the induction heating coil 22 to extend into the mounting hole 7 of the shift fork from below, maintaining an appropriate gap between the coil and the inner wall of the mounting hole. When a high-frequency alternating current passes through the induction heating coil 22, an alternating magnetic field is generated around the coil. This magnetic field passes through the metal inner wall of the mounting hole of the shift fork 6, inducing eddy currents inside the metal. When the eddy currents flow through the metal resistor, they generate Joule heat, achieving rapid heating of the inner wall of the mounting hole. Induction heating achieves localized heating of the shift fork mounting hole, concentrating heat on the mounting hole area that needs expansion, while keeping the temperature of other parts of the workpiece low and minimizing thermal deformation, thus ensuring assembly quality.

[0030] Furthermore, the lifting device 3 includes a back plate 32, a linear guide rail 31, a sliding plate 34, and a cylinder 33. The back plate 32 is mounted on the frame 1. The linear guide rail 31 and the cylinder 33 are mounted on the back plate 32. The sliding plate 34 is mounted on the slider of the linear guide rail 31. One end of the sliding plate 34 is connected to the output end of the cylinder 33, and the other end is connected to the lifting plate 8 for placing the shift fork 6. The cylinder 33 receives a control signal from the cylinder operating handle 12. The output end of the cylinder 33 extends and retracts, causing the sliding plate 34 to slide up and down along the slider of the linear guide rail 31. The sliding plate 34 then causes the lifting plate 8 and the shift fork 6 placed on it to move up and down together. The linear guide rail 31 ensures the linearity and stability of the movement, and the back plate 32 provides structural support for the entire lifting device.

[0031] Furthermore, the lifting plate 8 is provided with a clearance hole 9. In step S3, when the lifting device 3 drives the shift fork 6 to move downward, the induction heating coil 22 passes through the clearance hole 9 and extends into the assembly hole 7 of the shift fork 6. The design of the clearance hole 9 makes the relative movement between the induction heating coil 22 and the assembly hole 7 of the shift fork 6 possible. The lifting plate 8 can move downward with the shift fork 6 to allow the coil to pass into the assembly hole for heating. After heating is completed, the lifting plate 8 can move upward with the shift fork 6 to allow the coil to disengage from the assembly hole, realizing the automated connection between heating and part removal, and improving operating efficiency.

[0032] Furthermore, the lifting plate 8 is equipped with a positioning plate 10 and a positioning pin 11. In step S1, the shift fork 6 is positioned on the lifting plate 8 by the positioning plate 10 and the positioning pin 11. When placing the shift fork 6, the positioning plate 10 serves as the positioning reference surface for the shift fork 6, performing axial or radial coarse positioning of the shift fork 6; the positioning pin 11 is inserted into the corresponding positioning hole on the shift fork 6 or matches the outer contour of the shift fork 6 to perform precise positioning of the shift fork 6. Through the combined action of the positioning plate 10 and the positioning pin 11, it is ensured that the position of the shift fork 6 on the lifting plate 8 is consistent each time it is placed, thereby ensuring the relative positional accuracy between the assembly hole 7 of the shift fork 6 and the induction heating coil 22, ensuring the consistent heating effect of each workpiece in mass production, and improving the stability and consistency of assembly quality.

[0033] Furthermore, during the induction heating process, the induction heating coil 22 is cooled by a cooling device 4. The cooling device 4 includes a cooling pool 5, a water pump 41, an inlet pipe 42, and an outlet pipe 43. One end of the inlet pipe 42 is connected to the cooling pool 5, and the other end is connected to one end of the induction heating coil 22. One end of the outlet pipe 43 is connected to the other end of the induction heating coil 22, and the other end is connected to the cooling pool 5. The water pump 41 is installed on the inlet pipe 42. After the water pump 41 is started, it pumps the cooling water in the cooling pool 5 into the internal channel of the induction heating coil 22 through the inlet pipe 42. When the cooling water flows through the induction heating coil 22, it carries away the heat generated by the coil due to the high-frequency alternating current. Then, it flows back to the cooling pool 5 through the outlet pipe 43, forming a circulating cooling loop. The circulating water cooling method ensures the temperature stability of the induction heating coil 22 during continuous operation, prevents the coil from being damaged due to overheating, and extends the service life of the equipment.

[0034] Furthermore, the shift fork 6 is made of forged 45 steel with a hardness of 180–220 HB; the shift lever 20 is made of tempered steel with a hardness of 30–35 HRC. Because the shift fork 6 is made of a softer material and the shift lever 20 is made of a harder material, during the heat-fitting interference fit, the inner wall of the mounting hole of the shift fork 6 will preferentially undergo plastic deformation, with some material protruding into the annular groove 13 of the shift lever 20. This significantly increases the radial and axial friction between the shift lever 20 and the shift fork 6, effectively preventing relative rotation and axial slippage during use. This design of material hardness difference cleverly transforms the plastic deformation during the heat-fitting process into a factor beneficial to the connection strength.

[0035] Furthermore, the mounting hole 7 of the shift fork 6 is formed by drilling and reaming, with a dimensional accuracy of +0.02mm. Drilling and reaming involves first drilling a hole at the mounting hole location of the shift fork 6, and then using a reamer to finish the drilled hole to obtain high dimensional accuracy and surface quality. This dimensional accuracy indicates that the diameter of the mounting hole 7 is between the basic size and the basic size +0.02mm. Drilling and reaming is currently the dimensional accuracy level that can be consistently achieved in the machining of shift fork mounting holes. This accuracy requirement matches the existing conventional drilling and reaming capabilities, eliminating the need for more expensive and complex machining methods, which helps control manufacturing costs.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for assembling a gear shift lever and a shift fork, characterized in that, Includes the following steps: S1: Prepare a shift lever (20) and a shift fork (6), wherein the outer end of the shift lever (20) is machined with an annular groove (13). S2: Start the water pump (41), turn on the cooling, control the lifting plate (8) to the upper position by operating the cylinder handle (12), and place the fork (6) on the lifting plate (8); S3: Control the lifting plate (8) with the shift fork (6) to move downward to the lower position by operating the cylinder handle (12). The induction heating coil (22) is located in the hole of the shift fork (6) and the assembly hole of the shift fork (6) is heated by induction heating. S4: Heating is finished. Control the lifting plate (8) with the shift fork (6) to move upward to the upper position by operating the cylinder handle (12). The induction heating coil (22) leaves the shift fork hole. At this time, because the shift fork (6) is heated, the shift fork hole expands due to heating. Quickly insert the end of the shift lever (20) into the shift fork (6) hole and leave it for 5 seconds. S5: Cool the shift fork (6) to shrink the mounting hole of the shift fork (6) and fix the shift lever (20) in the mounting hole of the shift fork (6). The assembly is now complete.

2. The assembly method of a shift lever and a shift fork according to claim 1, characterized in that, The annular groove (13) has a groove width of 1.5 mm, a pitch of 15 mm, a machining length of 30 mm, and a machining depth of 0.2 mm.

3. The assembly method of a shift lever and a shift fork according to claim 1, characterized in that, The end of the shift lever (20) and the mounting hole (7) of the shift fork (6) are interference fit, and the interference between the end of the shift lever (20) and the mounting hole (7) of the shift fork (6) is 0.04mm to 0.09mm.

4. The assembly method of a shift lever and a shift fork according to claim 1, characterized in that, The induction heating is implemented by an induction heating coil (22), which is located below the heating position of the mounting hole (7) of the shift fork (6). When the lifting device (3) drives the shift fork (6) to move downward, the mounting hole (7) of the shift fork (6) is sleeved outside the induction heating coil (22).

5. The assembly method of a shift lever and a shift fork according to claim 4, characterized in that, The lifting device (3) includes a back plate (32), a linear guide rail (31), a sliding plate (34) and a cylinder (33). The back plate (32) is mounted on the frame (1). The linear guide rail (31) and the cylinder (33) are mounted on the back plate (32). The sliding plate (34) is mounted on the slider of the linear guide rail (31). One end of the sliding plate (34) is connected to the output end of the cylinder (33), and the other end is connected to a lifting plate (8) for placing the shift fork (6).

6. The assembly method of a shift lever and a shift fork according to claim 5, characterized in that, The lifting plate (8) has a clearance hole (9). In step S3, when the lifting device (3) drives the shift fork (6) to move downward, the induction heating coil (22) passes through the clearance hole (9) and extends into the assembly hole (7) of the shift fork (6).

7. The assembly method of a shift lever and a shift fork according to claim 5, characterized in that, The lifting plate (8) is provided with a positioning plate (10) and a positioning pin (11). In step S1, the shift fork (6) is positioned on the lifting plate (8) by the positioning plate (10) and the positioning pin (11).

8. The assembly method of a shift lever and a shift fork according to claim 4, characterized in that, During the induction heating process, the induction heating coil (22) is also cooled by a cooling device (4). The cooling device (4) includes a cooling pool (5), a water pump (41), an inlet pipe (42), and an outlet pipe (43). One end of the inlet pipe (42) is connected to the cooling pool (5), and the other end is connected to one end of the induction heating coil (22). One end of the outlet pipe (43) is connected to the other end of the induction heating coil (22), and the other end of the outlet pipe (43) is connected to the cooling pool (5). The water pump (41) is installed on the inlet pipe (42).

9. The assembly method of a shift lever and a shift fork according to claim 1, characterized in that, The material of the shift fork (6) is forged 45 steel with a hardness of 180-220HB; the material of the shift lever (20) is tempered material with a hardness of 30-35HRC.

10. The assembly method of a shift lever and a shift fork according to claim 1, characterized in that, The mounting hole (7) of the shift fork (6) is formed by drilling and reaming, and its dimensional accuracy is +0.02mm.

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