Machining method of alloy structural steel oil pump rotor

Abstract

The invention discloses a machining method of an alloy structural steel oil pump rotor. Comprising the following steps of material preparation, turning (rough machining of workpieces), heat treatment, turning (rough machining of outer circles and end faces), milling (rough machining of inner teeth), clamping, chemical heat treatment, heat treatment, grinding (semi-finishing of outer circles and end faces), grinding (finishing of outer circles and end faces), clamping and grinding (finishing of chamfers at outer circles) linear cutting machining (semi-finish machining of the inner teeth), grinding machining (finish machining of the inner teeth) and grinding machining (finish machining of chamfers at the inner teeth); in the process of machining the workpiece, the workpiece is subjected to a proper and reasonable heat treatment procedure, the internal stress of the workpiece is effectively eliminated, the size of the workpiece is stabilized, meanwhile, the procedure operation process is changed, the machining process is smoother, the operation method is simple and convenient, and the workpiece quality is stable.

Description

Technical Field

[0001] The invention relates to the field of machining alloy structure oil pump rotors, in particular to a machining method of alloy structure steel oil pump rotors. Background Art

[0002] The rotor oil pump is mainly composed of an inner rotor, an outer rotor, and an oil pump housing. It is a key component in the transmission. The inner rotor drives the outer rotor to rotate in the oil pump housing. The inner and outer rotors have high precision requirements, with dimensional accuracy IT6, surface roughness Ra0.8, carburizing and quenching, and surface hardness 58~62HRC.

[0003] At present, the main processing methods are: forging - normalizing + tempering - turning (turning the two end faces and inner and outer circles, enlarging the outer circle) - boring (drilling, boring positioning holes) - wire cutting (rough cutting of internal teeth) - heat treatment (carbonitriding, not quenching) - turning (turning to remove the carburized layer of the outer circle) - heat treatment (quenching 58-62HRC) - grinding (fine grinding of two planes) - grinding (fine grinding of the outer circle) - wire cutting (wire cutting of internal teeth) - turning (turning the outer circle) - grinding (fine grinding of the outer circle) - clamping (removing burrs) - flaw detection (magnetic flaw detection to check for cracks) - warehousing.

[0004] The existing processing methods have the following shortcomings:

[0005] (1) After the internal gear is finely machined, the outer circle needs to be roughed and finely machined, which has a certain impact on the accuracy of the internal gear and increases the weight of the raw materials and the processing steps;

[0006] (2) The processing cost of wire cutting internal teeth is high;

[0007] (3) Manual deburring, unstable quality;

[0008] (4) Due to the large positioning error, the shape and position tolerances of the workpiece are unstable. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides a method for processing an alloy structural steel oil pump rotor.

[0010] The present invention is achieved through the following technical solutions.

[0011] The present invention provides a method for processing an alloy structural steel oil pump rotor, comprising all the following steps:

[0012] S1: Material preparation, carburizing alloy structural steel forgings are selected;

[0013] S2: Turning: clamp the outer circle with a three-jaw chuck, turn the end face and inner hole, turn a section of the outer circle, clamp the outer circle, turn the other end face and the outer circle, and leave allowances for the end face, inner hole and outer circle;

[0014] S3: heat treatment, complete annealing;

[0015] S4: Turning: use a three-jaw chuck to clamp the outer circle, turn the end face and inner hole, clamp the inner hole, turn the other end face and the outer circle, and leave allowances for the end face, inner hole and outer circle;

[0016] S5: Milling, using machining center for processing, using fixture I on the machine tool to position and clamp the workpiece, positioning with one end face and the outer circle, first use drilling and expansion to process the root fillet of the tooth, then rough milling the internal teeth, and then fine milling the internal teeth;

[0017] S6: clamp processing to remove burrs;

[0018] S7: Chemical heat treatment, carburizing, quenching and tempering, to obtain a workpiece with a surface hardness of 58-62HRC and a core hardness of 32-45HRC;

[0019] S8: heat treatment, artificial aging;

[0020] S9: Grinding, using a cylindrical grinder, clamping the small circle of the inner teeth with wide soft jaws, and close to one end face of the workpiece to grind the outer circle and one end face of the workpiece;

[0021] S10: Grinding, using a surface grinder, using the ground end face as a reference to flat-grind the other end face;

[0022] S11: clamp processing, burr removal;

[0023] S12: Grinding, using an external cylindrical grinder, clamping the external circle with wide soft jaws, and close to one end of the workpiece, grinding the chamfers at both ends of the external circle;

[0024] S13: Wire cutting, using fast wire EDM machine, using fixture II to position and clamp the workpiece, cutting the internal teeth, leaving a margin;

[0025] S14: Grinding, using a vertical machining center machine tool, with the grinding head installed on the machine tool spindle, and the workpiece positioned and clamped with fixture II to grind the internal gear;

[0026] S15: Grinding: Use vertical machining center machine tool for processing, install grinding head on the machine tool spindle, use fixture Ⅱ to position and clamp the workpiece, chamfer one end of the internal teeth, use fixture Ⅱ to position and clamp the workpiece, and chamfer the other end of the internal teeth.

[0027] Preferably, in the S1 material preparation process, the forgings are forged according to the QJ500B-2014 standard and delivered in a normalized state.

[0028] Preferably, in S2, the outer circle of the blank is clamped with the hard jaws of a three-jaw chuck, the end face is corrected while clamping, one end face is turned, the thickness dimension is controlled, the inner hole is turned, the outer circle is turned, and the axial length of the outer circle is only about half of the total thickness.

[0029] Preferably, the soft jaws of the three-jaw chuck clamp the machined outer circle and press against the machined end face. The end face is machined to control the thickness dimension to 27±0.1mm and the outer circle dimension to φ190mm. The outer circle is allowed to be cut within the tolerance range.

[0030] Preferably, in S5, a cutting mark of less than or equal to 0.08 mm is allowed at the place where the fillet of the tooth root of the workpiece is tangent to the arc close to the two inner teeth.

[0031] Preferably, in S13, the clamp II is composed of a positioning seat, a positioning plate, a cylindrical positioning pin I, a conical positioning pin, a cylindrical positioning pin II and a pressure plate. The positioning holes for installing the cylindrical positioning pin I and the cylindrical positioning pin II on the positioning seat are combined with the positioning holes of the positioning plate, and the positioning plate is provided with a positioning hole for the conical positioning pin I; the three positioning holes are respectively matched with the outer circles of the positioning holes of the cylindrical positioning pin I, the cylindrical positioning pin II and the conical positioning pin I to ensure a clearance of 0.01 mm to 0.015 mm.

[0032] Preferably, the positioning seat is installed on the machine tool workbench, and the plane of the positioning seat is corrected to be parallel to a guide rail of the machine tool, with a parallelism of no more than 0.02 mm. The positioning hole of the positioning seat is accurately found with a detector, and the center deviation is no more than 0.02 mm. The positioning seat is pressed tightly on the machine tool workbench, and the workpiece is installed. The cylindrical positioning pin I, the cylindrical positioning pin II and the tapered positioning pin I are respectively installed in the corresponding positioning holes, the workpiece is positioned, and the position of the positioning plate is determined. The tapered part of the tapered positioning pin I is inserted into the tooth groove of the workpiece and is matched with the tooth groove without clearance, thereby positioning the workpiece;

[0033] Press the workpiece with a pressing plate, remove the conical locating pin Ⅰ, cylindrical locating pin Ⅰ, cylindrical locating pin Ⅱ and locating plate, and finish the internal teeth.

[0034] Preferably, during the grinding process in S14, a fixture II is used to position and clamp the workpiece, and the internal teeth are finely ground.

[0035] Preferably, during the grinding process in S15, one end of the internal teeth is chamfered by C0.3 mm, and the other end of the internal teeth is chamfered by C0.3 mm.

[0036] The beneficial effects of the present invention are: 1. The outer circle is first rough-machined, and then the inner teeth are rough-machined, and then the outer circle and one end face are fine-machined at the same time. The outer circle and one end face are fine-machined at one time to ensure the verticality requirement of the outer circle and the end face, so that the error of the outer circle is smaller, and at the same time it will not affect the accuracy of the inner teeth, thereby avoiding rework as much as possible.

[0037] 1. During the grinding process of the internal teeth, the workpiece is positioned using fixture II. After three finishing processes, the cutting and grinding of the internal teeth are realized, and the positioning reference of the three finishing processes is unified. The matching processing method is also used to process the splint, which reduces the manufacturing error of fixture II and has high workpiece positioning accuracy.

[0038] 2. During the processing of the workpiece, the workpiece is subjected to appropriate and reasonable heat treatment procedures to effectively eliminate the internal stress of the workpiece and stabilize the size of the workpiece, so as to avoid deformation of the workpiece during use.

[0039] 4. Use a fast-feeding EDM machine to cut the internal teeth to speed up the cutting speed. At the same time, the internal teeth are finely ground by grinding, which can effectively remove the burn layer on the tooth surface caused by EDM wire cutting. The sharp edge chamfering is also changed from manual chamfering to machine tool chamfering. The chamfering size can be more accurately controlled to reduce errors, making the processing flow smoother, the operation method simpler, and the workpiece quality stable, thereby reducing the processing cost by about 7%. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the oil pump rotor to be processed according to the present invention;

[0041] Figure 2 yes Figure 1 An enlarged schematic diagram of part I;

[0042] Figure 3 It is a structural schematic diagram of rough machining of a workpiece according to the present invention;

[0043] Figure 4 It is a structural schematic diagram of semi-finishing the outer circle and end face of a workpiece according to the present invention;

[0044] Figure 5 It is a structural schematic diagram of the rough machining of the internal teeth of a workpiece according to the present invention;

[0045] Figure 6 It is a structural schematic diagram of the present invention for finishing the outer circle and one end face of a workpiece;

[0046] Figure 7 It is a structural schematic diagram of the present invention performing fine processing on the other end surface of the workpiece;

[0047] Figure 8 It is a structural schematic diagram of the present invention for finishing the chamfering of the outer circle of a workpiece;

[0048] Fig. 9 yes Figure 8 Schematic diagram of the enlarged structure of part II;

[0049] Fig.10It is a structural schematic diagram of semi-finishing of the inner teeth of a workpiece according to the present invention;

[0050] Fig.11 It is a structural schematic diagram of the present invention for finishing the internal teeth of a workpiece;

[0051] Fig.12 It is a structural schematic diagram of the present invention for finishing the chamfering of the inner teeth of a workpiece;

[0052] Fig.13 yes Fig.12 Schematic diagram of the enlarged structure of part III;

[0053] Fig.14 It is a schematic diagram of the structure of the clamp II used to display the present invention;

[0054] Explanation of the reference numerals: 141 - positioning seat; 142 - positioning plate; 143 - cylindrical positioning pin I; 144 - tapered positioning pin I; 145 - cylindrical positioning pin II; 146 - pressure plate; 147 - tapered positioning pin II. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0057] In an embodiment of the present application, a method for processing an alloy structural steel oil pump rotor comprises the following steps:

[0058] S1: Prepare materials, refer to Figure 1 , made of alloy structural steel 20CrMnTi-GB / T3077-2015 and forged according to II-QJ500B-2014.

[0059] S2: Reference Figure 3 , specifically, ordinary horizontal lathe is used for processing; the first step is to clamp the outer circle of the blank with the hard jaws of the three-jaw chuck, and correct the end face while clamping; turn one of the end faces to control the thickness dimension, the thickness dimension is 27mm + the allowance of the other end face, and turn the inner hole size Outer circle size The axial length of the outer circle is only about half of the total thickness.

[0060] In the second step, the soft jaws of the three-jaw chuck clamp the machined outer circle, and at the same time make the machined end face close to the three-jaw chuck; turn the other end face, control the thickness size to 27±0.1mm, and turn the outer circle size The outer circle is allowed to be cut within the tolerance range. The rough machining of the workpiece is realized and the size of the workpiece is controlled within the allowable error range.

[0061] S3: Heat treatment, complete annealing of the workpiece that has been processed on the outer circle and end face, heating temperature is 870℃±10℃, cooling to 150℃ in the furnace and air cooling out of the furnace; it helps to refine the grains, eliminate structural defects and residual stress, stabilize the workpiece size in preparation for subsequent processing and quenching.

[0062] S4: Reference Figure 4 , specifically, ordinary horizontal lathe is used for processing; the first step is to clamp the outer circle with the hard jaws of the three-jaw chuck and close to the end face, turn one end face, and turn out the end face, while ensuring that the other end face has a processing allowance, turn the inner hole, the inner hole size is The second step is to clamp the machined inner hole with the soft jaws of the three-jaw chuck and close it to the machined end face, turn the other end face, control the thickness dimension, the thickness dimension is 24.2±0.042mm, turn the outer circle, and control the outer circle dimension. The outer circle and end face of the workpiece are rough machined, and the outer circle and end face rough machining of the workpiece is completed.

[0063] S5: Milling, see Figure 5 Specifically, vertical machining center machine tool is used for processing; fixture I is installed on the machine tool workbench so that the plane of fixture I is parallel to one guide rail of the machine tool, positioning hole φD5 is calibrated, and the workpiece is positioned and clamped by fixture I; one end face and outer circle are positioned, and the root fillet of the workpiece is first processed by drilling and reaming, with a size of 26-R4.1mm. Then the internal teeth are roughly milled with a rough milling cutter, and then the internal teeth are milled with a fine milling cutter. The size of the internal teeth milled by the fine milling cutter is φ163.2mm and 13-R13.4mm. The root fillet of the workpiece is tangent to the two arcs, and the cutter mark of no more than 0.08mm is allowed to leave a margin; the rough processing of the internal teeth of the workpiece is realized.

[0064] S6: Clamp processing to remove burrs remaining after milling.

[0065] S7: Chemical heat treatment; carburizing temperature 920℃±10℃, carburizing medium: methanol 60~80 drops / min, kerosene 120~140 drops / min, carburizing time about 6.5h (specific time is determined by sample), after carburizing, put it in the pit tank for cooling. The carburizing layer depth is 0.8mm~1.3mm, which is the cutting allowance (0.4mm~0.5mm) + the final required carburizing layer depth (0.4mm~0.8mm).

[0066] The quenching heating temperature is 820℃±10℃, and the holding time is determined according to the furnace loading method, furnace loading amount and effective thickness of the workpiece. It is oil cooled and the oil temperature is 20℃~60℃.

[0067] The tempering heating temperature is 160℃±10℃. The holding time is determined according to the furnace loading method, furnace loading amount and effective thickness of the workpiece. Air cooling is used.

[0068] Obtaining a workpiece with a surface hardness of 58 to 62 HRC and a core hardness of 32 to 45 HRC helps to enhance the stability of the workpiece and avoid deformation of the workpiece as much as possible.

[0069] S8: Heat treatment; artificial aging, heating temperature 150℃±10℃, holding time 6h~8h; in order to eliminate the internal stress of the workpiece and stabilize the size, and reduce the deformation of the workpiece during processing and use.

[0070] S9: Grinding, see Figure 6 , processed by external cylindrical grinder, wide soft jaws are a kind of soft jaws commonly used in production sites, use wide soft jaws to clamp the small circle of internal teeth, and close to one end face of the workpiece, first fine grind the outer circle, the size is Grind one end face again; control the end face size And make the shape and position tolerance of the workpiece within the control range.

[0071] S10: Grinding, see Figure 7 , using a surface grinder, clamp the small circle of the inner teeth with wide soft jaws, and close to one end face of the workpiece, use the ground end face as a reference, and fine grind the other end face, and control the end face size to At the same time, the geometric tolerances of the workpiece are also controlled.

[0072] S11: Clamp processing, to remove the burrs remaining during the grinding process;

[0073] S12: Grinding, see Figure 8 and Fig. 9 , use an external cylindrical grinder to clamp the outer circle with wide soft jaws and press against one end face of the workpiece, and grind a chamfer of C0.3mm at one end of the outer circle; use wide soft jaws to clamp the outer circle and press against one end face of the workpiece, and grind a chamfer of C0.3mm at the other end of the outer circle.

[0074] Through the above three grinding processes, the finishing of the outer circle and one end face of the workpiece can be completed in one clamping, ensuring the verticality requirement of the outer circle and the end face. At the same time, the positioning reference is unified, the manufacturing error of the fixture is reduced, and the positioning accuracy is high.

[0075] S13: Wire cutting, see Fig.14, using a high-speed wire EDM machine tool for processing; using fixture II to position and clamp the workpiece. Fixture II consists of a positioning seat 141, a positioning plate 142, a cylindrical positioning pin I 143, a tapered positioning pin 144, a cylindrical positioning pin II 145 and a pressing plate 146. The positioning holes for installing cylindrical positioning pins I 143 and cylindrical positioning pins II 145 on the positioning seat 141 are combined with the positioning holes of the positioning plate 142, and the positioning plate 142 is equipped with a positioning hole for tapered positioning pin I 144; the three positioning holes are respectively processed in cooperation with the outer circles of cylindrical positioning pins I 143, cylindrical positioning pins II 145 and tapered positioning pins I 144, so as to realize the assembly of cylindrical positioning pins I 143, cylindrical positioning pins II 145 and tapered positioning pins I 144 on the positioning seat 141 and the positioning plate 142.

[0076] The specific combined processing method is as follows: install the locating seat 141 on the machine tool workbench, straighten the plane Pm of the locating seat 141 with a deviation of no more than 0.005mm, calibrate the locating hole φD14 of the locating seat 141 with a deviation of no more than 0.005mm; install the locating plate 142 on the locating seat 141 and press it tightly, then drill and bore the locating holes φD141, φD142, and φD143, measure the values ​​of the three holes, and record them.

[0077] The specific matching processing method is as follows: according to the actual measurement values ​​of the three positioning holes, the positioning outer circles of the cylindrical positioning pin Ⅰ143, the cylindrical positioning pin Ⅱ145 and the tapered positioning pin Ⅰ144 are ground to ensure a clearance of 0.01mm to 0.015mm.

[0078] Reference Fig.10 During the clamping process of the workpiece by fixture II, the locating seat 141 is installed on the machine tool workbench, and the plane Pm of the locating seat 141 is calibrated to be parallel to a guide rail of the machine tool, with a parallelism of no more than 0.02mm. The locating hole φD10 of the locating seat 141 is found with a detector, and the center deviation is no more than 0.02mm. The locating seat 141 is pressed tightly on the machine tool workbench and the workpiece is installed.

[0079] The cylindrical locating pin Ⅰ143, the cylindrical locating pin Ⅱ145 and the conical locating pin Ⅰ144 are respectively installed in the corresponding locating holes φD141, φD142, φD143 to position the workpiece and determine the position of the locating plate 142. The conical part of the conical locating pin Ⅰ144 is inserted into the tooth groove of the workpiece and fits with the tooth groove without clearance, thereby positioning the workpiece; the workpiece is pressed with the pressing plate 146, the conical locating pin Ⅰ144, the cylindrical locating pin Ⅰ143, the cylindrical locating pin Ⅱ145 and the locating plate 142 are removed, and the inner teeth are semi-finished. The inner teeth dimensions are 26-R3.8mm, 13-R13.05mm, and φ163.9mm.

[0080] S14: Grinding, see Fig.11, using a vertical machining center machine tool, the machine tool spindle is equipped with a grinding head, and the workpiece is positioned and clamped with fixture II. The positioning seat 141 is installed on the machine tool workbench, and the plane Pm of the positioning seat 141 is corrected with a micrometer to be parallel to a guide rail of the machine tool, and the parallelism is not greater than 0.01mm. The positioning hole of the positioning seat 141 is found with a micrometer, the size is φ187.5, and the center deviation is not greater than 0.01mm. The positioning seat 141 is pressed tightly on the machine tool workbench and the workpiece is installed.

[0081] The conical locating pin I144 is replaced by the conical locating pin II147, and the column locating pin I143, the cylindrical locating pin II145 and the conical locating pin II147 are respectively installed in the corresponding locating holes φD141, φD142, and φD143 to position the workpiece. The cylindrical locating pin I143 and the cylindrical locating pin II145 (with different positioning outer diameters) determine the position of the locating plate 142, and the conical part of the conical locating pin II147 is inserted into the tooth groove of the workpiece and fits with the tooth groove without clearance, thereby positioning the workpiece; the workpiece is pressed with the pressing plate 146, the conical locating pin II147, the cylindrical locating pin I143, the cylindrical locating pin II145 and the positioning plate 142 are removed, and the inner teeth of the workpiece are finely ground.

[0082] S15: Grinding: Refer to Fig.12 and Fig.13 , the vertical machining center machine tool is used for processing, the grinding head is installed on the machine tool spindle, the workpiece is positioned and clamped by the fixture II, the workpiece is positioned by the positioning seat 141, the column positioning pin I 143, the cylindrical positioning pin II 145 and the tapered positioning pin II 147, and finally the workpiece is pressed by the pressing plate 146, the tapered positioning pin II 147, the cylindrical positioning pin I 143, the cylindrical positioning pin II 145 and the positioning plate 142 are removed, and one end of the internal tooth is finely ground with a chamfer of C0.3mm;

[0083] The workpiece is then positioned by means of the positioning seat 141, the column positioning pin I 143, the cylindrical positioning pin II 145 and the conical positioning pin II 147, and finally the workpiece is clamped by means of the pressing plate 146, the conical positioning pin II 147, the cylindrical positioning pin I 143, the cylindrical positioning pin II 145 and the positioning plate 142 are removed, and the other end of the inner tooth is chamfered to C0.3mm.

[0084] Through one wire cutting process and two grinding processes, the inner teeth of the workpiece are semi-finely processed and finely processed in turn. The workpiece is positioned and fixed by fixture II. The same positioning tools and positioning methods are used in the finishing process, so that the positioning references of the three finishing processes are unified. At the same time, the fixture is assembled by the matching processing method, which reduces the manufacturing error of fixture II and has high positioning accuracy. Grinding is also used to remove the burn layer of the tooth surface caused by electric spark wire cutting, so that the performance is improved. The sharp edge chamfering is changed from manual chamfering to machine tool chamfering, the chamfering size is controlled, the processing flow is more reasonable, and the operation method is convenient.

[0085] The outer circle and end face of the workpiece are first fine-machined, and then the inner teeth of the workpiece are fine-machined. Compared with the original technology, damage to the inner teeth during fine-machined outer circle and end face of the workpiece is avoided as much as possible, thereby improving the finished product turnover rate of the workpiece and avoiding rework of the workpiece as much as possible. At the same time, by inserting a reasonable heat treatment process, the mechanical properties of the workpiece are guaranteed, the deformation of the workpiece during use is reduced, and the processing cost of the workpiece is reduced.

[0086] S16: Flaw detection, magnetic flaw detection, check whether the workpiece has cracks to ensure the qualified rate of the finished workpiece.

[0087] S17: Storage.

[0088] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for processing an alloy structural steel oil pump rotor, characterized in that: Include all of the following steps: S1: Material preparation, carburizing alloy structural steel forgings are selected; S2: Turning: clamp the outer circle with a three-jaw chuck, turn the end face and inner hole, turn a section of the outer circle, clamp the outer circle, turn the other end face and the outer circle, and leave allowances for the end face, inner hole and outer circle; S3: heat treatment, complete annealing; S4: Turning: clamp the outer circle with a three-jaw chuck, turn the end face and inner hole, clamp the inner hole, turn the other end face and the outer circle, and leave allowances for the end face, inner hole and outer circle; S5: Milling, using machining center for processing, using fixture I on the machine tool to position and clamp the workpiece, positioning with one end face and the outer circle, first use drilling and expansion to process the root fillet of the tooth, then rough milling the internal teeth, and then fine milling the internal teeth; S6: clamp processing to remove burrs; S7: Chemical heat treatment, carburizing, quenching and tempering, to obtain a workpiece with a surface hardness of 58-62HRC and a core hardness of 32-45HRC; S8: heat treatment, artificial aging; S9: Grinding, using a cylindrical grinder, clamping the small circle of the inner teeth with wide soft jaws, and close to one end face of the workpiece to grind the outer circle and one end face of the workpiece; S10: Grinding, using a surface grinder, using the ground end face as a reference to flat-grind the other end face; S11: clamp processing, burr removal; S12: Grinding: Use an external cylindrical grinder to grind the external circle with wide soft jaws and close to one end of the workpiece to grind chamfers at both ends of the external circle; S13: Wire cutting, using fast wire EDM machine, using fixture II to position and clamp the workpiece, cutting the internal teeth, leaving a margin; S14: Grinding, using a vertical machining center machine tool, with the grinding head installed on the machine tool spindle, and the workpiece positioned and clamped with fixture II to grind the internal gear; S15: Grinding: Use vertical machining center machine tool for processing, install grinding head on the machine tool spindle, use fixture Ⅱ to position and clamp the workpiece, chamfer one end of the internal teeth, use fixture Ⅱ to position and clamp the workpiece, and chamfer the other end of the internal teeth.

2. The method for processing an alloy structural steel oil pump rotor according to claim 1, characterized in that: In the S1 material preparation process, the forgings are forged according to the QJ500B-2014 standard and delivered in the normalized state.

3. The method for processing an alloy structural steel oil pump rotor according to claim 1, characterized in that: In the S2, the outer circle of the blank is clamped with the hard jaws of the three-jaw chuck, the end face is corrected while clamping, one end face is turned, the thickness dimension is controlled, the inner hole is turned, the outer circle is turned, and the axial length of the outer circle is only about half of the total thickness.

4. The method for processing an alloy structural steel oil pump rotor according to claim 1, characterized in that: In S2, the soft jaws of the three-jaw chuck clamp the machined outer circle and press against the machined end face, machine the end face, control the thickness, and machine the outer circle. The outer circle is allowed to be connected with the tool within the tolerance range.

5. The method for processing an alloy structural steel oil pump rotor according to claim 1, characterized in that: In the above S5, a cutting mark of less than or equal to 0.08 mm is allowed at the place where the fillet of the tooth root of the workpiece is tangent to the arc near the two inner teeth.

6. The method for processing an alloy structural steel oil pump rotor according to claim 1, characterized in that: Said S13, the clamp II is composed of a positioning seat (141), a positioning plate (142), a cylindrical positioning pin I (143), a conical positioning pin (144), a cylindrical positioning pin II (145) and a pressure plate (146); the positioning holes for installing the cylindrical positioning pin I (143) and the cylindrical positioning pin II (145) on the positioning seat (141) are combined with the positioning holes of the positioning plate (142); the positioning plate (142) is provided with a positioning hole for the conical positioning pin I (144); the three positioning holes are respectively matched with the outer circles of the positioning holes of the cylindrical positioning pin I (143), the cylindrical positioning pin II (145) and the conical positioning pin I (144) to ensure a clearance of 0.01 mm to 0.015 mm.

7. The method for processing an alloy structural steel oil pump rotor according to claim 1, characterized in that: The positioning seat (141) is installed on the machine tool workbench, and the plane of the positioning seat (141) is calibrated to be parallel to a guide rail of the machine tool, and the parallelism is not greater than 0.02mm. The positioning hole of the positioning seat (141) is accurately found by a detector, and the center deviation is not greater than 0.02mm. The positioning seat (141) is pressed tightly on the machine tool workbench, and a workpiece is installed. The cylindrical positioning pin I (143), the cylindrical positioning pin II (145) and the tapered positioning pin I (144) are respectively installed in the corresponding positioning holes, and the workpiece is positioned, and the position of the positioning plate (142) is determined. The tapered part of the tapered positioning pin I (144) is inserted into the tooth groove of the workpiece to form a gapless fit with the tooth groove, thereby positioning the workpiece; The workpiece is pressed with a pressing plate (146), and the conical positioning pin I (144), the cylindrical positioning pin I (143), the cylindrical positioning pin II (145) and the positioning plate (142) are removed to fine-machine the internal teeth.

8. The method for processing an alloy structural steel oil pump rotor according to claim 1, characterized in that: During the grinding process in S14, the workpiece is positioned and clamped by fixture II, and the internal teeth are finely ground.

9. The method for processing an alloy structural steel oil pump rotor as claimed in claim 1, characterized in that: During the grinding process in S15, one end of the internal teeth is chamfered by C0.3 mm, and the other end of the internal teeth is chamfered by C0.3 mm.

Images