A machining method for ensuring the centering accuracy of an eccentric gear of a mechanical press

Abstract

The application discloses a machining method for ensuring the centering precision of an eccentric gear of a mechanical press, the eccentric gear comprising an eccentric wheel and two gearwheels, and comprises the following steps: on one side end face of each of the gearwheels and the eccentric wheel, a first process key groove is machined along a line connecting the center of the end face of the gearwheel and the center of a reference tooth valley; on the two side end faces of the eccentric wheel, a second process key groove is respectively machined along a line connecting the center of the inner hole of the eccentric wheel and the center of the eccentric outer circle; a process key is respectively fixed and installed in each second process key groove; the two gearwheels are respectively positioned and matched with the corresponding process keys at the two ends of the eccentric wheel through the first process key grooves of the gearwheels, assembled to the two ends of the eccentric wheel, and the gearwheels and the eccentric wheel are fastened. The application only needs to align the process key groove of the gearwheel with the process key to complete positioning, the centering precision is directly ensured by the machining precision of the numerical control machine tool, and the centering precision is high and easy to ensure.

Description

Technical Field

[0001] This invention belongs to the field of machining and assembly technology, and particularly relates to a machining method for ensuring the centering accuracy of eccentric gears in mechanical presses. Background Technology

[0002] The eccentric gear assembly of the main drive beam of a mechanical press typically consists of two large gears, an eccentric wheel, and a connecting rod bushing assembly. During assembly, the connecting rod assembly is mounted on the central eccentric outer circle of the eccentric wheel, and the two large gears are mounted on the outer circles at both ends of the eccentric wheel. The key accuracy requirement after assembly is that the lines connecting the inner center of the two large gears to the center of the reference tooth valley should coincide with the lines connecting the center of the eccentric outer circle and the center of the inner hole of the eccentric wheel, respectively; that is, the three center lines should be coplanar, with a tolerance of no more than 0.02 mm.

[0003] In the prior art, the commonly used manufacturing method for the above-mentioned eccentric gear assembly is as follows: First, place the first large gear on the platform shim, with the A-side of this large gear facing upwards and the B-side of the eccentric wheel facing downwards. Install the outer circle of the eccentric wheel into the inner hole of the gear, align it with the engagement hole, and pre-tighten it with the engagement screw; then, using the reference tooth valley of the second large gear, determine two measuring tooth valleys on the left and right sides, spanning the same number of teeth. Place the positioning ball of the measuring instrument into the two measuring tooth valleys respectively, and measure the shortest distances L1 and L2 to the eccentric outer circle of the eccentric wheel. Figure 1 As shown, the difference between the two must not exceed 0.02mm; otherwise, the fitter must repeatedly adjust the circumferential position of the eccentric wheel until the difference meets the requirement. Then, tighten the pre-tightened engagement screws and install the first large gear and eccentric wheel engagement assembly onto the gantry milling machine table, clamping this large gear facing upwards. Drill and bore the pin hole, then cold-install the pin. Next, flip the eccentric wheel and clamp it, then insert the connecting rod copper sleeve assembly onto the eccentric outer diameter of the eccentric wheel. Finally, insert the second large gear, A-face downwards, onto the outer diameter of the eccentric wheel. Align the engagement hole with the engagement screw, pre-tighten it, and use a dial indicator to check the error between the reference tooth valley side generatrix of the second large gear and the reference tooth valley side generatrix of the first large gear. The error should not exceed 0.02mm. Otherwise, the fitter needs to repeatedly adjust the circumferential position of the second large gear until the error meets the requirements. After that, tighten the pre-tightened engagement screw, install the second large gear and eccentric wheel engagement part onto the gantry milling machine worktable, clamp the second large gear facing upwards, drill and bore the pin hole, and cold install the pin.

[0004] However, the existing manufacturing methods have obvious defects and shortcomings: the entire assembly process relies heavily on manual measurement and repeated adjustments by fitters, the centering accuracy adjustment is very difficult, the operation is complex and difficult, the centering accuracy of the large gear and the eccentric wheel is extremely difficult to guarantee, the production efficiency is low, and the accuracy stability is poor.

[0005] Therefore, there is an urgent need for a machining method that can simplify operation, improve centering accuracy, and is easy to guarantee. Summary of the Invention

[0006] To address the problems of difficulty in adjusting the centering accuracy of eccentric gear assemblies, difficulty in guaranteeing accuracy, and complexity of operation in existing technologies, this invention provides a processing method to ensure the centering accuracy of eccentric gears in mechanical presses. This method is characterized by simple operation, centering accuracy directly guaranteed by CNC machine tools, high accuracy, and ease of guarantee, enabling efficient and high-precision assembly of large gears and eccentric wheels.

[0007] This invention is implemented as follows: a machining method for ensuring the centering accuracy of an eccentric gear in a mechanical press, the eccentric gear comprising an eccentric wheel and two large gears, including the following steps: On the end face of each of the large gears that mates with the eccentric wheel, a first process keyway is machined along the line connecting the center of the end face of the large gear and the center of the reference tooth valley. On both end faces of the eccentric wheel, second process keyways are respectively machined along the line connecting the center of the inner hole of the eccentric wheel and the center of the outer circle of the eccentric wheel; Process keys are fixedly installed in each of the second process keyways; The two large gears are respectively positioned and engaged with the corresponding process keys at both ends of the eccentric wheel through their respective first process keyways, and then assembled to both ends of the eccentric wheel, and the large gears and the eccentric wheel are fastened.

[0008] In the above technical solution, preferably, it further includes: after fastening the large gear and the eccentric wheel, machining the pin holes of the large gear and the eccentric wheel, and cold-installing the pins.

[0009] In the above technical solution, preferably, the specific assembly sequence of the two large gears is as follows: First, the first large gear is positioned and assembled to one end of the eccentric wheel using a process key and then tightened. This completes the pin hole machining and cold fitting of the large gear and eccentric wheel at that end. Then assemble the connecting rod copper sleeve assembly onto the eccentric outer circle of the eccentric wheel; Then, the second large gear is positioned and assembled to the other end of the eccentric wheel using a process key and tightened, completing the pin hole machining and cold-fitting of the large gear and eccentric wheel at this end.

[0010] In the above technical solution, preferably, the symmetry error of the first process keyway is no greater than 0.02 mm, and the symmetry error of the second process keyway is no greater than 0.02 mm.

[0011] In the above technical solution, preferably, the process key and the second process keyway are interference fit, and the interference amount is 0.01mm to 0.02mm.

[0012] In the above technical solution, preferably, the fitting clearance between the first process keyway and the process key is 0.01mm to 0.02mm.

[0013] In the above technical solution, preferably, the groove width tolerance of the first process keyway is H7, and the groove width tolerance of the second process keyway is K7.

[0014] In the above technical solution, preferably, the process key is fastened in the second process keyway by a first engagement screw.

[0015] In the above technical solution, preferably, the large gear and the eccentric wheel are fastened together by a second engagement screw.

[0016] In the above technical solution, preferably, before machining the first process keyway, the end face of the large gear is placed flat on the equal height pad of the CNC gantry milling machine with the end face facing upward. The origin of the coordinate system is determined according to the inner circle of the large gear, and a measuring rod is placed in the reference tooth valley. The center of the reference tooth valley is determined according to the outer circle of the measuring rod, thereby determining the machining position of the first process keyway.

[0017] The advantages and positive effects of this invention are: 1. Without changing the original eccentric gear body structure, this invention completely changes the traditional assembly mode of manual measurement and repeated adjustment by only adding process keyways and process keys, without adding any additional complex structures. Positioning can be completed simply by aligning the process keyway of the large gear with the process key. The operation is simple, the assembly time is greatly shortened, and ordinary operators can complete the assembly without relying on the manual adjustment of highly skilled fitters.

[0018] 2. This invention can predict the alignment accuracy after assembly by detecting the machining accuracy of the keyway. The alignment accuracy is directly guaranteed by the machining accuracy of the CNC machine tool (symmetry ≤ 0.02mm). The alignment accuracy is high and easy to guarantee, avoiding human error. The accuracy is stable and reliable, the yield is high, the manufacturing cost is low, and it is easy to promote. Attached Figure Description

[0019] The technical solutions of the embodiments of this application will be further described in detail below with reference to the accompanying drawings. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of this application. In addition, unless otherwise specified, these drawings are only intended to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0020] Figure 1 A schematic diagram of eccentric gear phase accuracy adjustment in the prior art; Figure 2 This is a perspective view of the large gear in an embodiment of the present invention; Figure 3This is a front view of the large gear in an embodiment of the present invention; Figure 4 This is a rear view of the large gear in an embodiment of the present invention; Figure 5 yes Figure 3 DD sectional view; Figure 6 This is a perspective view of the eccentric wheel in an embodiment of the present invention; Figure 7 This is a front view of the eccentric wheel in an embodiment of the present invention; Figure 8 yes Figure 7 EE sectional view; Figure 9 This is a perspective view of the connecting rod copper sleeve assembly in an embodiment of the present invention; Figure 10 This is a perspective view of the connecting rod copper sleeve assembly in an embodiment of the present invention; Figure 11 This is a front view of the connecting rod copper sleeve assembly in an embodiment of the present invention; Figure 12 yes Figure 11 FF sectional view.

[0021] In the figure: 1. Connecting rod copper sleeve assembly; 2. Large gear; 2-1. First process keyway; 3. Eccentric wheel; 3-1. Second process keyway; 4. Process key; 5. First locking screw; 6. Pin; 7. Second locking screw. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the following embodiments are provided, and detailed descriptions are given below in conjunction with the accompanying drawings: In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "joining," "installation," and "assembly" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] Please see Figures 2 to 12 The present invention provides a machining method for ensuring the centering accuracy of an eccentric gear in a mechanical press. The eccentric gear includes an eccentric wheel and two large gears, and includes the following steps: On one end face (A) of each large gear 2 that mates with the eccentric wheel 3, a first process keyway is machined along the line connecting the center of the end face of the large gear 2 and the center of the reference tooth valley; on the two end faces (B and C) of the eccentric wheel 3, a second process keyway is machined along the line connecting the center of the inner hole of the eccentric wheel 3 and the center of the outer circle of the eccentric wheel; process keys 4 are fixedly installed in each of the second process keyways; the two large gears 2 are respectively positioned and engaged with the corresponding process keys 4 at both ends of the eccentric wheel 3 through their respective first process keyways, assembled to both ends of the eccentric wheel 3, and the large gears 2 and the eccentric wheel 3 are tightened.

[0025] By setting process keyways and process keys 4 on the large gear 2 and eccentric wheel 3 respectively, a key positioning method is adopted to replace the manual measurement and repeated adjustments in the existing technology, achieving rapid and accurate alignment between the large gear 2 and the eccentric wheel 3. Since the machining position accuracy of the keyways is guaranteed by the CNC machine tool, during assembly, positioning can be completed simply by aligning the first process keyway of the large gear 2 with the process key 4 on the eccentric wheel 3. The operation is simple, and the alignment accuracy is easy to guarantee.

[0026] In a preferred embodiment, after fastening the large gear 2 and the eccentric wheel 3, the pin holes of the large gear 2 and the eccentric wheel 3 are machined together, and the pin 6 is cold-installed.

[0027] After the key is positioned and tightened, the pin hole is machined and the pin 6 is cold-installed, which ensures the positional accuracy of the pin hole, further fixes the relative position of the large gear 2 and the eccentric wheel 3, prevents circumferential displacement during use, and improves the long-term stability of the assembly.

[0028] As a preferred embodiment, the specific assembly sequence of the two large gears 2 is as follows: First, the first large gear 2 is positioned and assembled to one end of the eccentric wheel 3 using the process key 4 and then tightened, completing the pin hole machining and cold-fitting of the pin 6 between the large gear 2 and the eccentric wheel 3 at that end; then, the connecting rod copper sleeve assembly 1 is assembled onto the eccentric outer circle of the eccentric wheel 3; then, the second large gear 2 is positioned and assembled to the other end of the eccentric wheel 3 using the process key 4 and then tightened, completing the pin hole machining and cold-fitting of the pin 6 between the large gear 2 and the eccentric wheel 3 at that end.

[0029] This assembly sequence fully considers the structural characteristics of the eccentric gear assembly. First, one end of the large gear 2 is assembled and the pin hole is machined, avoiding interference with the positioning of that end in subsequent operations. Then, the connecting rod copper sleeve assembly 1 is assembled, followed by the assembly of the other end of the large gear 2 and the machining of the pin hole, ensuring the feasibility of the entire assembly process and the continuity of precision transfer. This sequence is logically clear and facilitates production line operation.

[0030] In a preferred embodiment, the symmetry error of the first process keyway is no greater than 0.02 mm, and the symmetry error of the second process keyway is no greater than 0.02 mm.

[0031] This precision requirement ensures that the center line of the keyway coincides with the theoretical center line (the line connecting the center of the gear and the center of the reference tooth valley, and the line connecting the center of the inner hole of the eccentric wheel and the center of the outer circle of the eccentric wheel), with the error controlled within 0.02mm. This ensures that the coplanarity of the three center lines after assembly meets the design requirements, and that the CNC machine tool can stably achieve this precision.

[0032] In a preferred embodiment, the process key 4 and the second process keyway are interference fit, with an interference amount of 0.01mm to 0.02mm.

[0033] This interference fit securely fixes the process key 4 within the second process keyway of the eccentric wheel 3, preventing it from loosening or falling off during the assembly of the large gear 2. Simultaneously, the interference amount is controlled within 0.01-0.02mm, ensuring both reliable fixing and ease of press-fitting.

[0034] In a preferred embodiment, the fitting clearance between the first process keyway and the process key 4 is 0.01mm to 0.02mm.

[0035] This clearance design ensures that the large gear 2 can be smoothly fitted into the process key 4 during assembly, while the clearance is extremely small, resulting in high positioning accuracy. Compared with the existing technology of direct assembly without positioning, this clearance value satisfies both assembly convenience and centering accuracy requirements.

[0036] In a preferred embodiment, the width tolerance of the first process keyway is H7, and the width tolerance of the second process keyway is K7.

[0037] H7 and K7 tolerances are commonly used fit tolerances in machining, corresponding to clearance fits in the hole-basis system and transition fits in the shaft-basis system, respectively. H7 ensures that the fit clearance between the first process keyway and process key 4 is controllable, and K7 ensures that the interference fit between the second process keyway and process key 4 is controllable. The combination of the two realizes the function of "fixing the key on the eccentric wheel and guiding and positioning the keyway on the large gear".

[0038] In a preferred embodiment, the process key 4 is secured in the second process keyway by the first engagement screw 5.

[0039] In addition to the interference fit, a first set screw 5 is added to further secure the process key 4. This double securing ensures that the process key 4 will not move axially or come off during use, improving assembly reliability. There are usually two of these screws, located on the bottom surface of the keyway.

[0040] In a preferred embodiment, the large gear 2 and the eccentric wheel 3 are fastened together by the second engagement screw 7.

[0041] After the key positioning is completed, the second engaging screw 7 is used to engage the large gear 2 with the end face of the eccentric wheel 3, achieving preliminary axial and circumferential fastening, which facilitates subsequent pin hole machining. There are usually multiple screws (such as 6 or 8) evenly distributed around the circumference to ensure uniformity of the fastening force.

[0042] In a preferred embodiment, before machining the first process keyway, the end face of the large gear 2 is placed flat on the leveling pad of the CNC gantry milling machine with the end face facing upward. The origin of the coordinate system is determined by the inner circle of the large gear 2, and a measuring rod is placed in the reference tooth valley. The center of the reference tooth valley is determined by the outer circle of the measuring rod, thereby determining the machining position of the first process keyway.

[0043] This positioning and alignment method accurately establishes the spatial relationship between the geometric center of the large gear 2 and the center of the reference tooth valley. The origin is determined by the inner hole, and the tooth valley center is indirectly characterized by a gauge bar, thus accurately drawing the line connecting the gear center and the reference tooth valley center, ensuring the accuracy of the first process keyway machining position. This method is simple to operate, highly accurate, and fully utilizes the precision advantages of CNC machine tools.

[0044] The working principle of this invention is as follows: by pre-machining process keyways with strict positional accuracy requirements on the end faces of the large gear 2 and the eccentric wheel 3, and fixing the process key 4 in the keyway of the eccentric wheel 3, the precise circumferential positioning of the large gear 2 and the eccentric wheel 3 is achieved by using the cooperation between the key and the keyway, thereby ensuring that the reference tooth valley centerline of the large gear 2 and the eccentric outer circle centerline of the eccentric wheel 3 are coplanar (alignment accuracy ≤ 0.02mm).

[0045] The following is based on Figure 10 Taking the eccentric gear shown as an example, the specific implementation process of the present invention is explained as follows: 1. After precision machining of the outer shape and tooth profile of the large gear 2, see... Figures 2-5 As shown, mark the line connecting the center of the large gear and the center of the reference tooth valley on surface A. Then, place the large gear with surface A facing upwards on the CNC gantry milling machine's leveling pad, align and clamp it according to the marked line, and determine the origin of the coordinate system according to the φ840H7 circle of the gear's inner hole. Place a φ40 gauge bar in the reference tooth valley, and determine the center of the reference tooth valley according to the outer circle of the gauge bar. Machining a process keyway on the line connecting the center of the gear and the center of the reference tooth valley on surface A of the large gear, with a keyway width of 20H7, requires that the center of the process keyway be on the line connecting the center of the gear and the center of the reference tooth valley, with a symmetry error of no more than 0.02mm.

[0046] 2. Mount on a CNC gantry milling machine, see... Figures 6-8As shown, the finished eccentric wheel 3 is placed flat on the V-block of the worktable with its two outer diameters flat. It is then clamped and aligned with the outer diameters to ensure the inner hole axis is aligned with the Y-axis (beam) of the gantry milling machine. The origin of the coordinate system is determined by the inner hole φ590H7 (+0.08 / 0) circle, and the center is determined by the eccentric outer diameter φ1520 (-0.425 / -0.475). A process keyway is machined on both the B and C surfaces of the eccentric wheel, with a width of 20 (0 / -0.021). The center of the process keyway must be on the line connecting the center of the inner hole and the center of the eccentric outer diameter, with a symmetry error not exceeding 0.02mm. Two M5 threaded holes are machined on the bottom surface of each process keyway.

[0047] 3. Install one process key 4 in each of the process keyways on surfaces B and C of the eccentric wheel, with an interference fit of 0.01-0.02mm, and tighten with M5 engagement screws. See [link / details]. Figures 10-12 As shown.

[0048] 4. Place the first large gear, A-side up, on the platform's level shims. Hoist the eccentric wheel, B-side down, and insert the outer diameter of the eccentric wheel (φ840g6) into the inner hole of the large gear (φ840H7). Position the large gear using the process keyway of the large gear and the process key of the eccentric wheel. The clearance between the process keyway and the process key should be 0.01-0.02mm. Tighten the large gear with six M36 locking screws. (See...) Figures 10-12 As shown.

[0049] 5. Using a CNC gantry milling machine, clamp the large gear upwards and simultaneously drill and bore the six φ85H7 pin holes of this large gear 2 and the eccentric wheel 3. (See...) Figure 3 , Figure 4 As shown.

[0050] 6. Cold-fitting 6 φ85 pins, see 6 Figures 10-12 As shown.

[0051] 7. Place the assembled large gear face down on the platform's leveling pads. Then, insert the connecting rod copper sleeve assembly 1 onto the eccentric outer diameter of the φ1520 (-0.425 / -0.475) eccentric wheel. (See...) Figures 10-12 As shown.

[0052] 8. Hoist the second large gear 2, with A facing down. Insert the inner hole of the large gear φ840H7 onto the outer circle of the eccentric wheel φ840g6, and assemble it together with the process keyway of the large gear and the process key of the eccentric wheel. Then tighten the large gear with six M36 engagement screws. See Figures 10-12 As shown.

[0053] 9. Using a CNC gantry milling machine, clamp the large gear upwards and simultaneously drill and bore the six φ85H7 pin holes of the large gear 2 and the eccentric wheel 3. (See...) Figure 3 , Figure 4 As shown.

[0054] 10. Six cold-packed φ85 pins (see details) Figures 10-12 As shown.

[0055] In summary, this invention involves machining a process keyway on the line connecting the gear center and the reference tooth valley center on surface A of the large gear 2, controlling the symmetry error to be no greater than 0.02 mm; machining process keyways on surfaces B and C of the eccentric wheel 3 respectively, requiring the center of the process keyway to be on the line connecting the center of the inner hole and the center of the outer circle of the eccentric wheel, controlling the symmetry error to be no greater than 0.02 mm; fitting a process key on the process keyway of the eccentric wheel with an interference fit of 0.01-0.02 mm; and assembling the large gear and the eccentric wheel using the process key for positioning to ensure the alignment accuracy of the large gear and the eccentric wheel, with an error no greater than 0.02 mm. Compared with existing manufacturing technologies, this invention has the advantages of simple operation, manufacturing accuracy guaranteed by CNC machine tools, and high and easily guaranteed alignment accuracy.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A machining method for ensuring the centering accuracy of an eccentric gear in a mechanical press, the eccentric gear comprising an eccentric wheel and two large gears, characterized in that, Includes the following steps: On the end face of each of the large gears that mates with the eccentric wheel, a first process keyway is machined along the line connecting the center of the end face of the large gear and the center of the reference tooth valley. On both end faces of the eccentric wheel, second process keyways are respectively machined along the line connecting the center of the inner hole of the eccentric wheel and the center of the outer circle of the eccentric wheel; Process keys are fixedly installed in each of the second process keyways; The two large gears are respectively positioned and engaged with the corresponding process keys at both ends of the eccentric wheel through their respective first process keyways, and then assembled to both ends of the eccentric wheel, and the large gears and the eccentric wheel are fastened.

2. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, Also includes: After fastening the large gear and the eccentric wheel, the pin holes of the large gear and the eccentric wheel are machined together, and the pins are cold-installed.

3. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 2, characterized in that, The specific assembly sequence of the two large gears is as follows: First, the first large gear is positioned and assembled to one end of the eccentric wheel using a process key and then tightened. This completes the pin hole machining and cold fitting of the large gear and eccentric wheel at that end. Then assemble the connecting rod copper sleeve assembly onto the eccentric outer circle of the eccentric wheel; Then, the second large gear is positioned and assembled to the other end of the eccentric wheel using a process key and tightened, completing the pin hole machining and cold-fitting of the large gear and eccentric wheel at this end.

4. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, The symmetry error of the first process keyway is no greater than 0.02 mm, and the symmetry error of the second process keyway is no greater than 0.02 mm.

5. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, The process key and the second process keyway are interference fit, with an interference amount of 0.01mm to 0.02mm.

6. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, The clearance between the first process keyway and the process key is 0.01mm to 0.02mm.

7. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, The width tolerance of the first process keyway is H7, and the width tolerance of the second process keyway is K7.

8. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, The process key is secured in the second process keyway by a first engagement screw.

9. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, The large gear and the eccentric wheel are fastened together by a second engagement screw.

10. The machining method for ensuring the centering accuracy of eccentric gears in a mechanical press according to claim 1, characterized in that, Before machining the first process keyway, the end face of the large gear is placed flat on the leveling pad of the CNC gantry milling machine with the end face facing upward. The origin of the coordinate system is determined according to the inner circle of the large gear. A measuring bar is placed in the reference tooth valley. The center of the reference tooth valley is determined according to the outer circle of the measuring bar, thereby determining the machining position of the first process keyway.

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