Large-diameter deep-hole piston rod machining method

Abstract

The invention provides a large-diameter deep-hole piston rod machining method which comprises the following steps: milling the left and right end faces of a metal bar after blanking, and punching a center hole; roughly turning outer circles of phi D2 and phi D3; a flat rod head L6 of the piston rod is pre-milled, and a phi d1 hole is pre-drilled; carrying out straightening treatment after hardening and tempering; performing semi-finish turning on the outer circles of phi D2 and phi D3; milling, drilling and forming L6 and phi d1 holes; an ultrasonic-assisted deep hole drilling device is adopted to drill a phi d2 hole in the axial direction of the metal bar, a piston rod flat part rod head is clamped, a B2.5 center hole in the right end is jacked, a phi D2 outer circle is erected, the hole opening size of the phi d2 hole is turned, and the phi D2 outer circle is subjected to finish turning; grinding the outer circle of phi D2 to the size before electroplating; and carrying out electroplating and polishing treatment on the plated layer section L3 of the metal bar. According to the machining method, the cutting resistance when the deep hole drill drills the deep hole can be reduced, the drilling precision can be improved, the deep hole drilling efficiency can be improved, the machining allowance can be reduced, the tool loss can be reduced, and the requirement of excircle machining coaxiality can be met without deviation correction of the deep hole.

Description

Technical Field

[0001] The invention relates to the field of piston rod processing, and in particular to a method for processing a large-diameter deep-hole piston rod. Background Art

[0002] Intelligent coal mining needs to ensure the straightness of the hydraulic support of the working face, and the accurate measurement of the displacement sensor is the basis. Usually, when installing a jack with a displacement sensor, the displacement sensor is installed on a large-diameter deep-hole piston rod, and then the telescopic displacement of the jack is accurately measured in real time. This installation method will be affected by the deep hole processing accuracy, and the displacement sensor is also easy to interfere with the deep hole, thereby damaging the sensor. Usually, the processing technology of large-diameter deep-hole piston rods is cutting, flat-head milling, rough turning, tempering, straightening, semi-finishing turning, drilling deep holes, deep hole correction, turning deep holes, fine turning, milling flat, drilling, grinding outer circles, polishing, electroplating, and secondary polishing. When drilling deep holes, deep hole drilling equipment is often used to drill deep holes. Since the conventional deep hole drilling processing deep hole deflection accuracy is one thousandth, the depth range of the blind hole of the large-diameter deep hole piston rod is 900mm to 1360mm, which will cause the coaxiality error range of the finished deep hole and the outer circle to be generally about 1mm, and the accuracy is low. At the same time, the piston rod is subjected to a large tensile force during the hydraulic support moving process, the processing allowance of the flat part of the piston rod is large, and the mechanical properties of its core are reduced due to the limitation of the depth of the hardening layer, which makes the hinge hole of the flat part of the piston rod easy to break and fail.

[0003] In order to improve the coaxiality requirements, the invention patent with the authorization announcement number CN109531068B discloses a method for controlling the coaxiality of the deep hole and the outer circle of a deep hole piston rod, and the specific steps include: (a) turning the end face of the big head end and the end face of the hole end of the piston rod flat, semi-finishing the outer circles of the piston rod, and drilling a blind hole from the center of the hole end; (b) measuring the wall thickness around the deep part of the blind hole and calculating the corrected size of the outer circle of the big head end; (c) using the corrected size, aligning the position corresponding to the central axis of the blind hole on the outer circle of the big head end, and turning two reference outer circles on each outer circle of the piston rod; (d) fixing the piston rod with the two reference outer circles as the reference, turning the end face of the big head end flat, correcting the center hole of the end face of the big head end, turning the outer circle of the big head end to the required size through the center hole of the big head end, turning the end face of the hole end flat, turning the inner stop of the hole end, and turning other outer circles to the required size through the inner stop of the hole end. The method for controlling the coaxiality between the deep hole and the outer circle of the deep hole piston rod has the advantages of novel design, good product quality, low production cost and high production efficiency. However, the method improves the coaxiality between the deep hole and the outer circle and the processing accuracy of the deep hole by correction during processing, and the processing allowance is large and the processing steps are complicated. Summary of the invention

[0004] In order to reduce the cutting resistance when drilling deep holes, improve the drilling accuracy, enhance the efficiency of deep hole drilling, reduce the machining allowance, reduce the tool loss, and realize the deep hole without correction to ensure the coaxiality requirements of the outer circle, the technical solution adopted by the present invention is: a large diameter deep hole piston rod processing method, comprising the following steps:

[0005] After cutting with a flat head milling machine, mill the left and right end faces of the metal bar and drill a center hole B2.5;

[0006] Rough turning: Rough turning of the outer diameter of metal bars ΦD2 and ΦD3;

[0007] Pre-milling and drilling: pre-milling one end of the metal bar to form the flat part of the piston rod head L6, and pre-drilling a Φd1 hole on the flat part of the piston rod head;

[0008] Quenching and straightening: straightening the metal bar after quenching and tempering;

[0009] Semi-finish turning of metal bar material ΦD2, ΦD3 outer circle;

[0010] Final milling, drilling, milling and forming the piston rod flat part head L6 and drilling and forming Φd1 hole;

[0011] Drilling deep holes: clamp the flat part of the piston rod, mount the outer circle of the metal bar material ΦD2, and use an ultrasonic-assisted deep hole drilling device to drill a Φd2 hole along the axial direction of the metal bar material, wherein the coaxiality of the Φd2 hole and the outer circle of the metal bar material ΦD2 is less than 0.3mm;

[0012] Turn the deep hole and finish turn the flat part of the piston rod, press the B2.5 center hole on the right end, mount the outer circle of the metal bar material ΦD2, turn the hole size of the Φd2 hole, and finish turn the outer circle of the metal bar material ΦD2;

[0013] Grinding the outer circle of the metal bar material ΦD2 to the size before electroplating, forming a metal bar material coating section L3;

[0014] Electroplating and polishing The metal bar material coating section L3 is electroplated and polished.

[0015] Based on the above, in order to ensure the subsequent processing size, the rough turning step includes: clamping the outer circle of the right end of the metal bar, using the top tip to top the B2.5 center hole of the left end of the metal bar, rough turning the outer circles ΦD2 and ΦD3 of the metal bar, and leaving a radial allowance of 5mm.

[0016] Based on the above, the pre-milling and flattening drilling steps include: using milling and drilling equipment to pre-mill one end of the metal bar to form the flat part head L6 of the piston rod, and pre-drilling the Φd1 hole; wherein the piston rod flat part head L6 has a 6mm allowance in the thickness direction, the Φd1 hole has a 5mm allowance in the radial direction, and a 5mm allowance on the end face.

[0017] Based on the above, the semi-finishing step includes: using a floating two-jaw chuck to clamp the flat part of the piston rod, using a top point to top the B2.5 center holes on the left and right ends, and semi-finishing turning the outer circle ΦD2 and the outer circle ΦD3 of the metal bar, wherein the radial allowance of the outer circle ΦD2 and the outer circle ΦD3 are both 2mm, and the end face allowance is 2mm.

[0018] Based on the above, the deep hole finishing step includes: using a floating two-jaw chuck to clamp the flat part of the piston rod, using a top to top the right end B2.5 center hole, using a center frame to hold the outer circle of the metal bar material ΦD2, and turning the various sizes of the deep hole opening;

[0019] After deep hole processing is completed, the center frame is retracted, and the left end hole is chamfered by using the tailstock center top to perform 1.5×30° chamfering, and the outer circle of the metal bar ΦD2 is precision turned.

[0020] Based on the above, in order to realize ultrasonic-assisted intermittent drilling, the ultrasonic-assisted deep hole drilling device includes a machine tool spindle traveling along the drilling direction, an ultrasonic deep hole drilling mechanism, and a supporting clamping mechanism;

[0021] The machine tool spindle is used to drive the ultrasonic deep hole drilling mechanism to perform vibration intermittent drilling on the piston rod workpiece;

[0022] The ultrasonic deep hole drilling mechanism is detachably connected to the machine tool spindle and is used for vibration intermittent drilling of the piston rod workpiece;

[0023] The supporting and clamping mechanism is arranged outside the ultrasonic deep hole drilling mechanism and the piston rod workpiece, and is used to support the ultrasonic deep hole drilling mechanism and the piston rod workpiece.

[0024] Based on the above, the ultrasonic deep hole drilling mechanism includes an ultrasonic deep hole drilling tool holder, an ultrasonic amplitude transformer, a gun drill tool holder, an ultrasonic transducer, an ultrasonic energy transmission transmitting module, an ultrasonic energy transmission receiving module and an ultrasonic electrical control unit;

[0025] The ultrasonic deep hole drilling tool holder is bolted to the machine tool spindle, and the ultrasonic transducer is arranged inside the ultrasonic deep hole drilling tool holder;

[0026] The ultrasonic horn is connected to the outer end of the ultrasonic deep hole drilling shank, and the outer end of the ultrasonic horn is provided with a spring chuck for mounting the gun drill shank;

[0027] The ultrasonic energy receiving module is mounted on the outer circle of the ultrasonic horn through a mounting bracket, the ultrasonic energy receiving module is connected to the ultrasonic energy transmitting module, and the ultrasonic energy transmitting module is connected to the ultrasonic electrical control unit through a power line;

[0028] The machine tool spindle, the ultrasonic deep hole drilling handle, the ultrasonic amplitude transformer and the gun drilling tool bar are coaxially arranged;

[0029] The ultrasonic deep hole drilling mechanism is used to convert electrical energy into ultrasonic waves, which are transmitted to the gun drill arbor via the ultrasonic amplitude transformer, forming a resonance point at the tip position of the gun drill arbor, and after being combined with the movement direction of the machine tool spindle, high-frequency vibration is generated along the drilling direction to perform vibration intermittent drilling on the piston rod workpiece.

[0030] Based on the above, in order to facilitate clamping of the piston rod workpiece, the support clamping mechanism includes a support guide sleeve arranged on the outside of the gun drill rod, a center frame arranged on the outside of the piston rod workpiece, and a floating two-jaw chuck clamped at one end of the piston rod workpiece.

[0031] Among them, the floating two-jaw chuck has the functions of auxiliary clamping and automatic compensation of the piston rod, and the center holes or chamfers on the left and right ends are used as the positioning reference for piston rod processing. When the spindle drives the piston rod to rotate at a high speed, the floating two-jaw chuck can still ensure the stability of clamping the piston rod, thereby increasing the feed rate and the processing accuracy to 0.01mm.

[0032] The present invention has substantial characteristics and progress compared with the prior art. Specifically, the large-diameter deep-hole piston rod processing method provided by the present invention optimizes the processing flow, improves the processing benchmark, merges the deep hole turning and fine turning processes, and unifies the processing benchmarks of the two, thereby improving the processing accuracy. At the same time, a mobile programming program is added to the tailstock to drive the center to realize automatic feeding, reducing the number of workpiece transfer and clamping times, and improving the processing efficiency by about 30%.

[0033] Furthermore, by adding a pre-milling process before tempering, on the one hand, the mechanical properties of the flat part of the piston rod can be improved; on the other hand, the workpiece is not tempered during pre-milling, and the hardness is low and it is easy to process, which improves the milling efficiency and reduces tool loss.

[0034] Furthermore, by shortening the blanking specifications of the metal bars to reduce the rough turning allowance, the processing efficiency is further improved and the raw material cost is reduced.

[0035] Furthermore, the large-diameter deep-hole piston rod processing method is realized based on an ultrasonic-assisted deep-hole drilling device. The ultrasonic-assisted deep-hole drilling device converts electrical energy into ultrasonic energy through an ultrasonic deep-hole drilling processing system, and transmits it to the gun drill tip through an ultrasonic amplitude transformer to form resonance, thereby obtaining a large impact acceleration, which is combined with the movement direction of the machine tool spindle to vibrate at a high frequency in the drilling direction. It can form intermittent processing, reduce heat generation, have a good chip breaking effect and facilitate chip removal, and take away a large amount of heat, thereby increasing the service life of the gun drill arbor.

[0036] At the same time, the device can also significantly reduce the drilling resistance of the gun drill, reduce the load of the machine tool, reduce deformation, improve drilling efficiency and drilling accuracy, ensure the coaxiality of the inner and outer circles, and finally eliminate the deep hole correction, while reducing tool wear, increasing the feed rate, and comprehensively improving the efficiency of deep hole drilling by about 40%. The precision turning clamping method is optimized from the three-jaw chuck clamping the right end ΦD1, the top top 1.5×30° chamfer on the left end to the floating floating two-jaw chuck clamping the piston rod flat rod head, the top top right end B2.5 center hole and the left end 1.5×30° chamfer, which is unified with the grinding processing benchmark, and the ΦD2 outer circle grinding amount is reduced by 0.15mm, improving the grinding efficiency by more than 25%.

[0037] Therefore, the large-diameter deep hole piston rod processing method provided by the present invention can reduce the cutting resistance when drilling deep holes, improve the drilling accuracy, enhance the efficiency of drilling deep holes, reduce the processing allowance, reduce the tool loss, and achieve the deep hole without the need for correction to ensure the coaxiality requirements of the external circle processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the piston rod structure formed by utilizing the large-diameter deep-hole piston rod processing method provided by the present invention.

[0039] Figure 2 , Figure 3 and Figure 4 The present invention is a schematic diagram of the process structure of a piston rod processed by the large-diameter deep-hole piston rod processing method provided by the present invention.

[0040] In the figure: 1. Machine tool spindle; 2. Slide; 3. Adapter; 4. Ultrasonic deep hole drilling tool holder; 5. Fixed frame; 6. Ultrasonic energy transmission transmitting module; 7. Ultrasonic transducer; 8. Ultrasonic energy transmission receiving module; 9. Spring chuck; 10. Ultrasonic amplitude transformer; 11. Gun drill tool rod; 12. Support guide sleeve; 13. Ultrasonic electrical control unit; 14. Center frame; 15. Piston rod workpiece; 16. Deep hole; 17. Floating two-jaw chuck; 18. Tail stock center; 19. Left end center. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0042] Example 1

[0043] This embodiment provides a method for processing a large-diameter deep-hole piston rod. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the specific steps include:

[0044] After cutting with a flat head milling machine, mill the left and right end faces of the metal bar and drill a center hole B2.5;

[0045] Rough turn the outer circle of the right end of the metal bar, use the top tip to punch the B2.5 center hole on the left end of the metal bar, and rough turn the outer circles ΦD2 and ΦD3 of the metal bar, leaving a radial allowance of 5mm.

[0046] Pre-milling and flat drilling: Use milling and drilling equipment to pre-mill one end of the metal bar to form the flat part head L6 of the piston rod, and pre-drill the Φd1 hole; the piston rod flat part head L6 has a 6mm allowance in the thickness direction, the Φd1 hole has a 5mm allowance in the radial direction, and a 5mm allowance on the end face.

[0047] Quenching and straightening, quenching and high temperature tempering, heat treatment hardness requirement: 240-280HBW, use press for straightening to ensure straightness and coaxiality requirements.

[0048] The semi-finishing turning uses a floating two-jaw chuck to clamp the flat part of the piston rod, and the top point tops the B2.5 center holes on the left and right ends. The ΦD2 outer circle and ΦD3 outer circle of the metal bar are semi-finishing turned, where the radial allowance of the ΦD2 outer circle and the ΦD3 outer circle are both 2mm, and the end face allowance is 2mm.

[0049] Final milling, drilling, milling and forming the piston rod flat part head L6 and drilling forming Φd1 hole.

[0050] For deep hole drilling, the two-jaw chuck clamps the flat part of the piston rod, the center frame holds the outer circle of Φ(D2+2), and an ultrasonic-assisted deep hole drilling device is used to drill a Φd2 hole. The coaxiality of the Φd2 deep hole and the outer circle ΦD2 is controlled within 0.3mm.

[0051] The floating two-jaw chuck is used to clamp the flat part of the piston rod for deep hole turning and precision turning. The top point is used to turn the B2.5 center hole on the right end. The center frame is used to set the Φ(D2+2) outer circle, and the various dimensions of the deep hole opening are turned. After the deep hole processing is completed, the center frame is retracted, the tailstock top point is used to turn the left end of the hole opening 1.5×30° chamfer, and the ΦD2 outer circle is precision turned to Φ(D2+0.25)mm. The remaining outer circles, grooves, chamfers, and fillets are turned to the drawing dimensions.

[0052] Grind the outer dome and top the center holes at both ends of the piston rod, roughly grind and finely grind the ΦD2 outer circle to the size before electroplating, top the center holes at both ends of the piston rod, polish the ΦD2 outer circle to remove grinding marks, further reduce the surface roughness of the parts, and ensure the bonding strength of the coating.

[0053] Electroplating and polishing: Electroplating treatment is performed on the metal bar material coating section L3, and the center holes at both ends of the piston rod are topped with the top. After electroplating, secondary leveling treatment is performed and the outer circle of ΦD2 is polished to reduce the surface roughness.

[0054] In the electroplating polishing step, the plating type can be selected from milky white chrome plating plus hard chrome plating, or copper-tin alloy plating plus hard chrome plating.

[0055] Specifically, in this embodiment, Figure 3As shown, in order to realize ultrasonic-assisted intermittent drilling, the ultrasonic-assisted deep hole drilling device includes a machine tool spindle 1 traveling on a slide 2 along a drilling direction, an ultrasonic deep hole drilling mechanism, and a supporting clamping mechanism.

[0056] The machine tool spindle 1 is used to drive the ultrasonic deep hole drilling mechanism to perform vibration intermittent drilling on the piston rod workpiece 15. The ultrasonic deep hole drilling mechanism is detachably connected to the machine tool spindle 1 and is used to perform vibration intermittent drilling on the piston rod workpiece 15.

[0057] The ultrasonic deep hole drilling mechanism includes an ultrasonic deep hole drilling handle 4, an ultrasonic amplitude transformer 10, a gun drill shank 11, an ultrasonic transducer 7, an ultrasonic energy transmission module 6, an ultrasonic energy transmission receiving module 8 and an ultrasonic electrical control unit 13.

[0058] The supporting and clamping mechanism is arranged outside the gun drill arbor 11 and the piston rod workpiece 15 , and is used to support the gun drill arbor 11 and the piston rod workpiece 15 when drilling a deep hole 16 .

[0059] The ultrasonic deep hole drilling tool holder 4 is bolted to the machine tool spindle 1 via a connecting plate 3 , and the ultrasonic transducer 7 is arranged inside the ultrasonic deep hole drilling tool holder 4 .

[0060] The ultrasonic horn 10 is connected to the outer end of the ultrasonic deep hole drilling shank 4 , and a spring chuck 9 for mounting the gun drill shank 11 is disposed at the outer end of the ultrasonic horn 10 .

[0061] The ultrasonic energy receiving module 8 is mounted on the outer circle of the ultrasonic horn 10 through a mounting bracket. The ultrasonic energy receiving module 8 is connected to the ultrasonic energy transmitting module 6, and the ultrasonic energy transmitting module 6 is connected to the ultrasonic electrical control unit 13 through a power line.

[0062] The machine tool spindle 1 , the ultrasonic deep hole drilling handle 4 , the ultrasonic horn 10 , and the gun drill shank 11 are coaxially arranged.

[0063] Specifically, the ultrasonic deep hole drilling mechanism is used to convert electrical energy into ultrasonic waves, which are transmitted to the gun drill arbor 11 via the ultrasonic amplitude transformer 10, forming a resonance point at the tip position of the gun drill arbor 11, and after being combined with the movement direction of the machine tool spindle 1, high-frequency vibration is generated along the drilling direction, thereby performing vibration intermittent drilling on the piston rod workpiece 15.

[0064] In order to facilitate the clamping of the piston rod workpiece, the support and clamping mechanism includes a support guide sleeve 12 arranged outside the gun drill arbor 11, a center frame 14 arranged outside the piston rod workpiece 15, a left end top 19, a tailstock top 18, and a floating two-jaw chuck 17 clamped at one end of the piston rod workpiece 15. A fixing frame 5 is also arranged outside the ultrasonic energy transmission module 6.

[0065] Example 2

[0066] This embodiment provides a method for processing a large-diameter deep hole piston rod. The main difference from Embodiment 1 is that in this embodiment: when the ultrasonic-assisted deep hole drilling device is used to drill a deep hole of diameter Φd2, a deep hole of depth L2 (0, +2) is drilled, and the ultrasonic frequency range is 15000 Hz to 30000 Hz. After the deep hole is formed, the coaxiality of the deep hole Φd2 and the outer circle ΦD2 is measured and controlled within 0.3 mm.

[0067] In order to verify that the large-diameter deep-hole piston rod processing method provided by the present invention can improve the drilling accuracy and realize that the deep hole can ensure the coaxiality requirement of the outer circle processing without correction, piston rods of different materials and different hole depths are processed respectively, and finally the coaxiality data of the deep hole Φd2 and the outer circle ΦD2 are measured. The test results are shown in Table 1. It can be seen from Table 1 that the large-diameter deep-hole piston rod processing method provided by the present invention can improve the drilling accuracy and realize that the deep hole can ensure the coaxiality requirement of the outer circle processing without correction when facing piston rods of different hole depths and different materials.

[0068] Table 1. Coaxiality measurement data of deep hole Φd2 and outer circle ΦD2

[0069] Material Hole depth(mm) Quantity (pcs) Coaxiality range (mm) 27SiMn 1170 30 0.1-0.25 30CrMnSi 1170 30 0.1-0.28 35CrMnSi 1170 30 0.12-0.26 27SiMn 1045 30 0.06-0.21 30CrMnSi 1045 30 0.08-0.24 35CrMnSi 1045 30 0.11-0.22 27SiMn 885 30 0.05-0.2 30CrMnSi 885 30 0.09-0.26 35CrMnSi 885 30 0.1-0.25

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A method for processing a large-diameter deep-hole piston rod, comprising the following steps: After cutting with a flat head milling machine, mill the left and right end faces of the metal bar and drill a center hole B2.5; Rough turning: Rough turning of the outer diameter of metal bars ΦD2 and ΦD3; Pre-milling and drilling: pre-milling one end of the metal bar to form the flat part of the piston rod head L6, and pre-drilling a Φd1 hole on the flat part of the piston rod head; Quenching and straightening: straightening the metal bar after quenching and tempering; Semi-finish turning: Semi-finish turning of metal bar material ΦD2, ΦD3 outer circle; Final milling, drilling, milling and forming the piston rod flat part, rod head L6 and drilling forming Φd1 hole; Drilling deep holes: clamp the flat part of the piston rod, mount the outer circle of the metal bar material ΦD2, and use an ultrasonic-assisted deep hole drilling device to drill a Φd2 hole along the axial direction of the metal bar material, wherein the coaxiality of the Φd2 hole and the outer circle of the metal bar material ΦD2 is less than 0.3mm; Turn the deep hole and finish turn the flat part of the piston rod, press the B2.5 center hole on the right end, mount the outer circle of the metal bar material ΦD2, turn the hole size of the Φd2 hole, and finish turn the outer circle of the metal bar material ΦD2; Grinding the outer circle of the metal bar material ΦD2 to the size before electroplating, forming a metal bar material coating section L3; Electroplating and polishing The metal bar material coating section L3 is electroplated and polished.

2. The method for processing a large-diameter deep-hole piston rod according to claim 1, characterized in that: The rough turning step includes: clamping the outer circle of the right end of the metal bar, using a top to top the B2.5 center hole of the left end of the metal bar, and rough turning the outer circles ΦD2 and ΦD3 of the metal bar, leaving a radial allowance of 5mm.

3. The method for processing a large-diameter deep-hole piston rod according to claim 2, characterized in that: The pre-milling and flattening drilling steps include: using a milling and drilling device to pre-mill one end of a metal bar to form a piston rod flat head L6, and pre-drilling a Φd1 hole; wherein a 6mm allowance is left in the thickness direction of the piston rod flat head L6, a 5mm allowance is left in the radial direction of the Φd1 hole, and a 5mm allowance is left on the end face.

4. The method for processing a large-diameter deep-hole piston rod according to claim 3, characterized in that: The semi-finishing step includes: using a floating two-jaw chuck to clamp the flat rod head of the piston rod, using a top point to top the B2.5 center holes on the left and right ends, and semi-finishing the outer circles of ΦD2 and ΦD3 of the metal bar, wherein the radial allowance of the outer circles of ΦD2 and ΦD3 is 2mm, and the end face allowance is 2mm.

5. The method for processing a large-diameter deep-hole piston rod according to claim 4, characterized in that: The deep hole finishing step comprises: using a floating two-jaw chuck to clamp the flat part of the piston rod, using a top to top the right end B2.5 center hole, using a center frame to hold the outer circle of the metal bar material ΦD2, and turning the various sizes of the deep hole opening; After deep hole processing is completed, the center frame is retracted, and the left end hole is chamfered using the tailstock center pin, and the outer circle of the metal bar ΦD2 is precision turned.

6. The method for machining a large-diameter deep-hole piston rod according to any one of claims 1 to 5, characterized in that: The ultrasonic-assisted deep hole drilling device comprises an ultrasonic deep hole drilling mechanism, a supporting clamping mechanism, and a machine tool spindle traveling along the drilling direction; The machine tool spindle is used to drive the ultrasonic deep hole drilling mechanism to perform vibration intermittent drilling on the piston rod workpiece; The ultrasonic deep hole drilling mechanism is detachably connected to the machine tool spindle and is used for vibration intermittent drilling of the piston rod workpiece; The supporting and clamping mechanism is arranged outside the ultrasonic deep hole drilling mechanism and the piston rod workpiece, and is used to support the ultrasonic deep hole drilling mechanism and the piston rod workpiece.

7. The method for processing a large-diameter deep-hole piston rod according to claim 6, characterized in that: The ultrasonic deep hole drilling mechanism comprises an ultrasonic deep hole drilling tool holder, an ultrasonic amplitude transformer, a gun drill tool holder, an ultrasonic transducer, an ultrasonic energy transmission transmitting module, an ultrasonic energy transmission receiving module and an ultrasonic electrical control unit; The ultrasonic deep hole drilling tool holder is bolted to the machine tool spindle, and the ultrasonic transducer is arranged inside the ultrasonic deep hole drilling tool holder; The ultrasonic horn is connected to the outer end of the ultrasonic deep hole drilling shank, and the outer end of the ultrasonic horn is provided with a spring chuck for mounting the gun drill shank; The ultrasonic energy receiving module is mounted on the outer circle of the ultrasonic horn through a mounting bracket, the ultrasonic energy receiving module is connected to the ultrasonic energy transmitting module, and the ultrasonic energy transmitting module is connected to the ultrasonic electrical control unit through a power line; The machine tool spindle, the ultrasonic deep hole drilling handle, the ultrasonic amplitude transformer and the gun drilling tool bar are coaxially arranged; The ultrasonic deep hole drilling mechanism is used to convert electrical energy into ultrasonic waves, which are transmitted to the gun drill arbor via the ultrasonic amplitude transformer, forming a resonance point at the tip position of the gun drill arbor, and after being combined with the movement of the machine tool spindle, high-frequency vibration is generated along the drilling direction, thereby performing vibration intermittent drilling on the piston rod workpiece.

8. The method for processing a large-diameter deep-hole piston rod according to claim 7, characterized in that: The supporting and clamping mechanism comprises a supporting guide sleeve arranged outside the gun drill tool rod, a center frame arranged outside the piston rod workpiece, and a floating two-jaw chuck clamped at one end of the piston rod workpiece.

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