Diesel engine piston rod cooling oil return inclined hole machining tool and machining method

Abstract

The invention discloses a diesel engine piston rod cooling oil return inclined hole machining tool and method.The machining tool comprises a rotary plate, a bottom plate, an L-shaped drill jig and two pressing assemblies, the bottom of the L-shaped drill jig is positioned and fixed to one end of the rotary plate, the bottom plate is fixed to a machine tool workbench, and the rotary plate is supported on the bottom plate through a rotary supporting mechanism; a mandrel assembly of the rotary supporting mechanism is arranged in the center of a rotary plate and the center of a bottom plate, and supporting assemblies are arranged between the lower sides of the two ends of the rotary plate and the upper sides of the two ends of the bottom plate. The machining method comprises the steps that (1) the machining tool and the piston rod are fixed to a machine tool workbench, (2) the rotary plate is rotated by an angle alpha anticlockwise and then locked, and then machining of a first oil return inclined hole is completed, and (4) the rotary plate is rotated by an angle 2 alpha clockwise, and then machining of a second oil return inclined hole is completed. The drilling of the oil return inclined hole can be completed at a time, and the machining quality and the machining efficiency of the oil return inclined hole are remarkably improved.

Description

Technical Field

[0001] The present invention relates to a processing tooling and a processing method for an inclined hole that obliquely intersects with the center hole of a shaft-like part at a small acute angle (≤30°), and particularly relates to a processing tooling and a processing method for an oil return inclined hole of a piston rod, belonging to the technical field of metal cutting processing. Background Art

[0002] The piston rod of a marine low-speed diesel engine (n < 300 r / min) is used to transmit power and is usually equipped with a liquid cooling system. Cooling oil enters the piston rod through a cooling oil pipe, and then is evenly sprayed onto the inner wall of the piston through a cooling nozzle to reduce the temperature of the piston, prevent overheating and wear. The heated cooling oil returns to the cooling oil tank through the oil return inclined hole.

[0003] The piston rod of a certain model of marine low-speed diesel engine is as Figure 1 shown: The piston rod 100 is processed from a forging with two ends and one rod. One end is a cylindrical end 10, and the other end is a flat end 20 with a bow-shaped block cut off from the upper and lower sides of the cylinder. A stepped through hole 101 with a large end diameter D is provided at the center of the cylindrical end 10 and is used as a guiding hole for the cooling oil pipe; two oil return inclined holes 201 with a diameter d = Φ35 mm are symmetrically provided at the flat end 20. The included angle α between the axis of the oil return inclined hole 201 and the axis of the stepped through hole 10 is 15°. The axes of the two oil return inclined holes 201 intersect at 30°, and the planes where the axes of the two oil return inclined holes 201 are located are respectively parallel to the planes on the upper and lower sides of the flat end 20.

[0004] The existing processing technology for the stepped through hole 101 and the two oil return inclined holes 201 of the piston rod is as follows:

[0005] First, the stepped through hole 101 is machined on a deep hole machine tool, and then the two oil return inclined holes 201 are respectively drilled. Since the axis of the oil return inclined hole 201 obliquely intersects with the axis of the stepped through hole 101, during the process of the drilled oil return inclined hole 201 penetrating through the stepped through hole 101, it is gradually penetrated by unilateral cutting, resulting in uneven force on the drill bit and large vibration. The aperture size of the oil return inclined hole 201 exceeds the tolerance, and the surface roughness of the hole wall of the oil return inclined hole 201 is much lower than the specified 3.2, and the processing performance is very poor.

[0006] Currently, a numerical control machine tool is also used to process the stepped through hole 101 and the two oil return inclined holes 201 of the piston rod. Its process drawing is as Figure 2 shown. After the counterbore 1011 of the stepped through hole 101 is machined, first, a keyway milling cutter is used to mill the guiding holes 2011 of the oil return inclined holes 201 respectively ( Figure 2 a), and then a drill bit is used to drill the oil return inclined holes 201 respectively until the tip of the oil return inclined hole 201 reaches the large end arc part 1012 of the large end counterbore 2011 ( Figure 2b), finally replace the milling cutter and continue to mill the oil return inclined hole 201 until the oil return inclined hole 201 communicates with the stepped through hole 101. Figure 2 c). The roughness of the oil return inclined hole 201 processed by the above method also cannot reach 3.2, and a fitter still needs to polish the surface of the oil return inclined hole 201.

[0007] The existing processing methods have problems such as multiple processes, multiple types of cutting tools used, uneven force on the milling cutter and large vibration when the oil return inclined hole 201 is milled through, resulting in out-of-tolerance aperture size of the oil return inclined hole 201, and the roughness of the hole wall of the oil return inclined hole 201 is much lower than the specified 3.2. The processing cost is high and the feed rate is small, thus resulting in low processing efficiency and poor processing quality. Summary of the Invention

[0008] The object of the present invention is to provide a processing tooling and processing method for the oil return inclined hole of the cooling oil of a diesel engine piston rod with high processing efficiency and good processing quality.

[0009] The present invention is realized through the following technical solutions:

[0010] A processing tooling for the oil return inclined hole of the cooling oil of a diesel engine piston rod, including a rotary plate, a bottom plate, an L-shaped drill jig and 2 sets of pressing components. The bottom of the L-shaped drill jig is positioned and fixed at one end of the rotary plate. The pressing components include a pressing plate, a V-shaped block and 2 double-headed bolts. The V-shaped blocks are spaced and fixed in the middle of the rotary plate. The middle of the piston rod is supported on 2 V-shaped blocks. The pressing plate is spaced and pressed on the upper side of the middle of the piston rod. The lower ends of the double-headed bolts respectively pass through both ends of the pressing plate and are screwed into the V-shaped blocks, and the piston rod is clamped and fixed in the 2 sets of pressing components respectively by the pressing plate nuts tightened on the upper ends of the double-headed bolts. The bottom plate is fixed on the machine tool workbench;

[0011] The rotary plate is supported on the bottom plate through a rotary support mechanism. The rotary support mechanism includes a core shaft assembly and a support assembly. The core shaft assembly is arranged at the centers of the rotary plate and the bottom plate, and includes a core shaft, a shaft sleeve, an upper gasket, a core shaft nut and 2 thrust ball bearings. The bottom flange of the core shaft is positioned and fixed on the upper side center of the bottom plate. The shaft sleeve is fixed at the center of the rotary plate. The upper end of the core shaft passes through the shaft sleeve. The thrust ball bearings installed at the upper and lower ends of the core shaft respectively abut against the upper and lower sides of the rotary plate;

[0012] The support assemblies are respectively arranged between the lower sides of both ends of the rotary plate and the upper sides of both ends of the bottom plate, and include an arc-shaped upper flat plate, an arc-shaped arc groove plate and a plurality of rolling balls. The arc-shaped upper flat plates are respectively fixed on the lower sides of both ends of the rotary plate. The arc-shaped arc groove plates are respectively fixed on the upper sides of both ends of the bottom plate. The arc-shaped upper flat plate and the arc-shaped arc groove plate are in corresponding up and down positions. The arc groove is located on the outer side of the arc-shaped arc groove plate. The center lines of the arc grooves of the 2 arc-shaped arc groove plates are concentric circles, and the center of the concentric circles is the axis of the core shaft; a plurality of rolling balls abutting against each other are respectively located in the arc grooves, and the upper edges of the plurality of rolling balls respectively abut against the lower side of the arc-shaped upper flat plate;

[0013] The rotary positioning components are respectively located on both sides of the L-shaped drill jig, and include a pair of drilling angle positioning plates and vertical stop pins arranged in pairs. The center line of the drilling angle positioning plate is perpendicular to the longitudinal center line of the bottom plate, and is respectively positioned and fixed at one end of the bottom plate and adjacent to the L-shaped drill jig. The vertical stop pins are symmetrically fixed at one end of the bottom plate and are respectively close to the corresponding drilling angle positioning plates. When the rotary plate rotates clockwise or counterclockwise to the in-place position, the longitudinal side of the rotary plate abuts against the outer edge of the corresponding vertical stop pin, and the lower end of the precision reaming bolt passes through the corner of the rotary plate and is screwed into the central threaded hole of the drilling angle positioning plate, thereby fixing the rotary plate and the L-shaped drill jig at the required deflection angle.

[0014] The object of the present invention can also be further achieved by the following technical measures.

[0015] Further, two inclined drill sleeves symmetrical about the vertical center line of the vertical plate of the L-shaped drill jig are fixed on the vertical plate, and the included angle 2α' between the axes of the two inclined drill sleeves matches the included angle 2α between the axes of the two inclined oil return holes on the flat end face of the piston rod. The inner side face of the vertical plate is used as the reference surface, and one end of the horizontal support pin is respectively fixed on the vertical plate.

[0016] Further, the center distance X between the two horizontal support pins is less than the length A of the lower side plane of the flat end of the piston rod, and the vertical distance Y between the center of the horizontal support pin and the center of the inclined drill sleeve is the sum of 1 / 2 of the thickness B of the flat end of the piston rod and the radius R of the horizontal support pin.

[0017] Further, the center distance C1 between the centers of the balls at the arc tops of the arc grooves of the two arc-shaped arc groove plates is greater than the center distance C2 between the stud bolts of the two sets of pressing components.

[0018] Further, dust-proof plates are respectively arranged on both longitudinal sides of the rotary plate.

[0019] Further, the difference between the height H1 of the drilling angle positioning plate and the height H2 of the support component: H1 - H2 = 0.10 - 0.20 mm.

[0020] A processing method for a processing tool for machining the inclined oil return holes of a diesel engine piston rod includes the following steps:

[0021] 1) Hoist the assembled processing tool onto the machine tool workbench. After aligning the bottom plate, fix the bottom plate on the machine tool workbench. Then support the middle part of the piston rod to be machined on two V-shaped blocks, and make the flat end face of the piston rod to be machined abut against the reference surface on the inner side of the vertical plate of the L-shaped drill jig. The lower side plane of the flat end of the piston rod is supported on two horizontal support pins. Align the axis of the piston rod to be parallel to the axis of the machine tool spindle. Press the pressure plates on the middle part of the piston rod respectively, and tighten them with the pressure plate nuts on the stud bolts respectively, so that the piston rod is clamped and fixed in the two sets of pressing components. Finally, lock the machine tool workbench.

[0022] 2) Rotate the rotary plate counterclockwise by an angle α so that one longitudinal side of the rotary plate abuts against the outer edge of a vertical stop pin. Then, pass the lower end of the precision reamed bolt through a corner of the rotary plate and screw it into the central threaded hole of a drilling angle positioning plate, thereby fixing the rotary plate and the L-shaped drill jig at the deflection angle required for an oil return inclined hole.

[0023] 3) Start the machine tool. The spindle of the machine tool drives the rotating drill bit to perform longitudinal feed. The drill bit drills into the flat end face of the piston rod under the guidance of the corresponding inclined drill bushing of the L-shaped drill jig. After drilling an oil return inclined hole with a depth of L in the flat end of the piston rod, withdraw the drill bit and unscrew the precision reamed bolt, and the rotary plate is disengaged from the fixed connection with the drilling angle positioning plate.

[0024] 4) Rotate the rotary plate clockwise by an angle of 2α so that the other longitudinal side of the rotary plate abuts against the outer edge of the corresponding vertical stop pin. Then, pass the lower end of the precision reamed bolt through the positioning pin hole at a corner of the rotary plate and screw it into the central threaded hole of another drilling angle positioning plate, thereby fixing the rotary plate and the L-shaped drill jig at the deflection angle required for another oil return inclined hole.

[0025] 5) Repeat the drilling process in step 3) to complete the drilling of another cooling oil return inclined hole with a depth of L in the flat end face of the piston rod.

[0026] The drilling depth L of the oil return inclined hole = L1 + L2, where L1 = 0.5(H - D) / sinα and L2 = 0.5d / tgα; in the formula:

[0027] H: The center distance of the oil return inclined hole; D: The diameter of the cooling oil pipe guide hole to be bored; d: The diameter of the cooling oil return inclined hole; α: The angle between the axis of the cooling oil return inclined hole and the axis of the piston rod.

[0028] The present invention does not require a numerical control machine tool and can complete the machining of the oil return inclined hole only by using an ordinary boring machine, significantly reducing the machining cost. The piston rod is reliably positioned and clamped through the pressing component and the L-shaped drill jig. After rotating the rotary plate around the axis of the core shaft and locking it, the axis of the oil return inclined hole of the piston rod is parallel to the axis of the machine tool spindle. The present invention can complete the drilling of the oil return inclined hole at one time only by using one type of drill bit, avoiding the vibration caused by unilateral cutting of the drill bit, and significantly improving the machining quality and machining efficiency of the oil return inclined hole.

[0029] The advantages and features of the present invention will be illustrated and explained through the non-limiting description of the following preferred embodiments, which are given only as examples with reference to the accompanying drawings. Description of the Drawings

[0030] Figure 1 is a cross-sectional view of the piston rod of a certain type of marine low-speed diesel engine;

[0031] Figure 2 It is a process drawing for machining two oil return inclined holes of the piston rod using a numerically controlled machine tool;

[0032] Figure 3 It is the front view of the piston rod positioned and clamped on the fixture of the present invention;

[0033] Figure 4 It is Figure 3 the left view;

[0034] Figure 5 It is Figure 3 the top view, at this time the rotary plate has rotated an angle of α around the axis of the core shaft and is ready to drill the first oil return inclined hole;

[0035] Figure 6 It is Figure 3 the top view, at this time the rotary plate has rotated an angle of -2α around the axis of the core shaft and is ready to drill the second oil return inclined hole;

[0036] Figure 7 It is an analysis drawing for determining the drilling depth L of the oil return inclined hole of the present invention. Specific embodiments

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0038] In the description of the present invention, terms indicating orientation or positional relationship such as "center", "upper", "lower", "left", "right", "inner", "outer", etc. are based on the orientation or positional relationship shown in the accompanying drawings, rather than indicating or implying that the device referred to must have a specific orientation.

[0039] As Figures 3 to 7 shown, the machining fixture for the cooling oil return inclined hole of the diesel engine piston rod of the present invention includes a rotary plate 1, a bottom plate 2, an L-shaped drill jig 3 and two sets of pressing components 4. The bottom of the L-shaped drill jig 3 is positioned and fixed on the left end of the rotary plate 1. The pressing component 4 includes a pressing plate 41, a V-shaped block 42 and two double-headed bolts 43. The V-shaped blocks 42 are fixedly spaced in the middle of the rotary plate 1. The middle of the piston rod 100 is supported on the two V-shaped blocks 42. The pressing plate 41 is spaced and pressed on the upper side of the middle of the piston rod 100. The lower ends of the double-headed bolts 43 respectively pass through both ends of the pressing plate 41 and are screwed into the V-shaped blocks 42, and the piston rod 100 is clamped and fixed in the two sets of pressing components 4 respectively by tightening the pressing plate nuts 44 on the upper ends of the double-headed bolts 43. The bottom plate 2 is fixed on the machine tool workbench 200.

[0040] As Figure 3As shown in the figure, the rotary plate 1 is supported on the bottom plate 2 by a rotary support mechanism 5. The rotary support mechanism 5 includes a mandrel assembly 51 and a support assembly 52. The mandrel assembly 51 is disposed at the centers of the rotary plate 1 and the bottom plate 2, and includes a mandrel 511, a bushing 512, an upper gasket 513, a mandrel nut 514, and two thrust ball bearings 515. The bottom flange 5111 of the mandrel is positioned and fixed at the center on the upper side of the bottom plate 2. The bushing 512 is fixed at the center of the rotary plate 1. The upper end of the mandrel 511 passes through the bushing 511, and the thrust ball bearings 515 installed at the upper and lower ends of the mandrel 511 respectively abut against the upper and lower sides of the rotary plate 1.

[0041] As Figures 3 to 5 shown in the figure, the support assembly 52 is respectively disposed between the lower sides of the two ends of the rotary plate 1 and the upper sides of the two ends of the bottom plate 2, and includes an arc-shaped upper flat plate 521, an arc-shaped circular arc groove plate 522, and a plurality of balls 523. The arc-shaped upper flat plates 521 are respectively fixed to the lower sides of the two ends of the rotary plate 1, and the arc-shaped circular arc groove plates 522 are respectively fixed to the upper sides of the two ends of the bottom plate 2. The arc-shaped upper flat plates 521 and the arc-shaped circular arc groove plates 522 are corresponding in the up-and-down positions. The circular arc groove 5221 is located on the outer side of the arc-shaped circular arc groove plate 522. The circular arc center lines of the circular arc grooves 5221 of the two arc-shaped circular arc groove plates 522 are concentric circles, and the center of the concentric circles is the axis of the mandrel 511. A plurality of mutually abutting balls 523 are respectively located in the circular arc grooves 5221, and the upper edges of the plurality of balls 523 respectively abut against the lower side of the arc-shaped upper flat plate 521. The structure of the circular arc groove 5221 instead of the integral annular groove is adopted, so that the number of balls 523 can be reduced by at least half, and the manufacturing cost of the present invention can be effectively reduced. The mandrel assembly 51 and the support assembly 52 of the present invention significantly reduce the resistance of the piston rod to rotate, and facilitate the drill bit 220 to align with the inclined drill sleeve 32 corresponding to the L-shaped drill die 3.

[0042] As Figure 5 and Figure 6 shown in the figure, the rotary positioning assemblies 6 are respectively located on both sides of the L-shaped drill die 3, and include paired drilling angle positioning plates 61 and vertical stop pins 62. The center lines of the drilling angle positioning plates 61 are perpendicular to the longitudinal center line of the bottom plate 2, and are respectively positioned and fixed on the left end of the bottom plate 2 and adjacent to the L-shaped drill die 3. The vertical stop pins 62 are symmetrically fixed on the left end of the bottom plate 2 and are respectively close to the corresponding drilling angle positioning plates 61. When the rotary plate 1 rotates clockwise or counterclockwise to the in-place position, the longitudinal side of the rotary plate 1 abuts against the outer edge of the corresponding vertical stop pin 62. The lower end of the precision bolt 8 passes through the positioning pin hole at the corner of the rotary plate and is screwed into the central threaded hole 611 of the drilling angle positioning plate 61, so as to fix the rotary plate 1 and the L-shaped drill die 3 at the required deflection angle.

[0043] As Figures 3 to 5As shown in the figure, two inclined drill bushes 32, which are symmetric about the vertical center line of the vertical plate 31 of the L-shaped drill jig 3, are fixed on the vertical plate 31. The included angle 2α' between the axes of the two inclined drill bushes 32 matches the included angle 2α between the axes of the two inclined oil return holes on the end face of the flat end 20 of the piston rod 100. The inner side surface of the vertical plate 31 is used as the reference surface, and one end of the horizontal support pin 33 is fixed on the vertical plate 31 respectively. In this embodiment, α = 15°.

[0044] The center distance X of the horizontal support pins 33 is less than the length A of the lower side plane of the flat end of the piston rod, and the vertical distance Y between the center of the horizontal support pin 33 and the center of the inclined drill bush 32 is the sum of half of the thickness B of the flat end of the piston rod and the radius R of the horizontal support pin. Ensure that the flat end 20 of the piston rod 100 is reliably and stably supported, and keep the axis of the machine tool spindle 210 consistent with the axis of the inclined drill bush 32.

[0045] As Figure 3 shown in the figure, the center distance C1 of the rolling balls at the arc tops of the lower arc grooves of the two arc-shaped lower arc groove plates 522 is greater than the center distance C2 of the stud bolts 43 of the two sets of pressing components 4, so that the piston rod 100 is stably supported.

[0046] As Figure 4 shown in the figure, dust-proof plates 7 are respectively arranged on the longitudinal two sides of the rotary plate 1 to prevent foreign objects from falling into the arc-shaped arc groove plates 522 or between the rolling balls 523 of the support assembly 52, and improve the reliability of the support assembly 52. The difference between the height H1 of the drilling angle positioning plate and the height H2 of the support assembly: H1 - H2 = 0.10 - 0.20 mm, which is convenient for locking the rotary plate 1, the L-shaped drill jig 3 and the piston rod 100 with the taper bolts 8 after the rotary plate 1 rotates to the upper side of the drilling angle positioning plate 61, and is convenient for drilling the oil return inclined hole 201.

[0047] As Figures 3 to 6 shown in the figure, a processing method for a processing tool for machining the cooling oil return inclined holes of a diesel engine piston rod includes the following steps:

[0048] 1) Hoist the assembled processing tool onto the machine tool workbench 200. After aligning the bottom plate 2, fix the bottom plate 2 on the machine tool workbench 200 with 4 fastening screws 21. Then support the middle part of the piston rod 100 to be processed on two V-shaped blocks 42, and make the end face of the flat end 20 of the piston rod 100 to be processed abut against the reference surface on the inner side of the vertical plate 31 of the L-shaped drill jig 4. The lower side plane of the flat end 20 of the piston rod 100 is supported on two horizontal support pins 33. Align the axis of the piston rod 100 to be parallel to the axis of the machine tool spindle 210. Press the pressure plates 41 on the middle part of the piston rod 100 respectively, and tighten them on the stud bolts 43 with the pressure plate nuts 44 respectively, so that the piston rod 100 is clamped and fixed in the two sets of pressing components 4, and finally lock the machine tool workbench 200.

[0049] 2) Rotate the rotary plate 1 counterclockwise by α = 15°, so that one longitudinal side of the rotary plate 1 abuts against the outer edge of a vertical stop pin 62. Then, pass the lower end of the precision reamed bolt 8 through a corner positioning pin hole of the rotary plate 1 and screw it into the central threaded hole 611 of a drilling angle positioning plate 61, thereby fixing the rotary plate 1 and the L-shaped drill jig 4 at the deflection angle required for an oil return inclined hole 201.

[0050] 3) Start the machine tool. The machine tool spindle 210 drives the rotating drill bit 220 to perform longitudinal feeding. The drill bit 220 drills into the flat end 20 end face of the piston rod 100 under the guidance of the corresponding inclined drill bushing 32 of the L-shaped drill jig. After drilling an oil return inclined hole 201 with a depth of L in the flat end 20 of the piston rod 100, withdraw the drill bit 220, and unscrew the precision reamed bolt 8. The rotary plate 1 is disengaged from the fixed connection with the drilling angle positioning plate 61.

[0051] 4) Rotate the rotary plate 1 clockwise by 2α = 30°, so that the other longitudinal side of the rotary plate 1 abuts against the outer edge of the corresponding vertical stop pin 62. Then, pass the lower end of the precision reamed bolt 8 through a corner positioning pin hole of the rotary plate 1 and screw it into the central threaded hole 611 of another drilling angle positioning plate 61, thereby fixing the rotary plate 1 and the L-shaped drill jig 3 at the deflection angle required for another oil return inclined hole 201.

[0052] 5) Repeat the drilling process in step 3) to complete the drilling of another oil return inclined hole 201 on the end face of the flat end 20 of the piston rod 100 with a depth of L.

[0053] As Figure 7 shown, the drilling depth L of the oil return inclined hole is obtained by the following formula,

[0054] L = L1 + L2, L1 = 0.5(H - D) / sinα, L2 = 0.5d / tgα. Where:

[0055] H: Center distance of the oil return inclined hole; D: Diameter of the cooling oil pipe guide hole to be bored; d: Diameter of the cooling oil return inclined hole; α: Angle between the axis of the cooling oil return inclined hole and the axis of the piston rod. The depth L of the oil return inclined hole is the sum of the hypotenuse L1 of the thickened right triangle on the left and the right-angled side L2 of the thickened right triangle in Figure 7 the figure.

[0056] Except for the above embodiments, the present invention may have other embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A processing tooling for the oil return inclined holes of a diesel engine piston rod cooling oil, comprising a rotary plate, a bottom plate, an L-shaped drill jig and 2 sets of pressing components. The bottom of the L-shaped drill jig is positioned and fixed at one end of the rotary plate. The pressing component includes a pressing plate, a V-shaped block and 2 double-headed bolts. The V-shaped blocks are fixedly spaced in the middle of the rotary plate. The middle of the piston rod is supported on the 2 V-shaped blocks. The pressing plate is spaced and pressed on the upper side of the middle of the diesel engine piston rod. The lower ends of the double-headed bolts respectively pass through both ends of the pressing plate and are screwed into the V-shaped blocks, and the piston rod is clamped and fixed in the 2 sets of pressing components respectively by the pressing plate nuts tightened on the upper ends of the double-headed bolts. The bottom plate is fixed on the machine tool workbench; Characterized in that, The rotary plate is supported on the bottom plate through a rotary support mechanism. The rotary support mechanism includes a core shaft assembly and a support assembly. The core shaft assembly is arranged at the center of the rotary plate and the center of the bottom plate, and includes a core shaft, a bushing, an upper gasket, a core shaft nut and 2 thrust ball bearings. The bottom flange of the core shaft is positioned and fixed on the upper side center of the bottom plate. The bushing is fixed at the center of the rotary plate. The upper end of the core shaft passes through the bushing. The thrust ball bearings installed at the upper and lower ends of the core shaft respectively abut against the upper and lower sides of the rotary plate; The support assemblies are respectively arranged between the lower sides of both ends of the rotary plate and the upper sides of both ends of the bottom plate, and include an arc-shaped upper flat plate, an arc-shaped lower circular arc groove plate and a plurality of rolling balls. The arc-shaped upper flat plates are respectively fixed on the lower sides of both ends of the rotary plate. The arc-shaped lower circular arc groove plates are respectively fixed on the upper sides of both ends of the bottom plate. The arc-shaped upper flat plate and the arc-shaped lower circular arc groove plate are corresponding in the up and down positions. The circular arc groove is located on the outer side of the arc-shaped lower circular arc groove plate. The circular arc groove center lines of the 2 arc-shaped circular arc groove plates are concentric. The center of the concentric circles is the axis of the core shaft. A plurality of rolling balls abuting against each other are respectively located in the lower circular arc grooves, and the upper edges of the plurality of rolling balls respectively abut against the lower side of the arc-shaped upper flat plate; The rotary positioning assemblies are respectively located on both sides of the L-shaped drill jig, and include paired drilling angle positioning plates and vertical stop pins. The center line of the drilling angle positioning plate is perpendicular to the longitudinal center line of the bottom plate, and is respectively positioned and fixed at one end of the bottom plate and adjacent to the L-shaped drill jig. The vertical stop pins are symmetrically fixed at one end of the bottom plate and are respectively close to the corresponding drilling angle positioning plates. When the rotary plate rotates clockwise or counterclockwise to the in-place position, one longitudinal side of the rotary plate abuts against the outer edge of the corresponding vertical stop pin. The lower end of the precision bolt passes through the corner of the rotary plate and is screwed into the central threaded hole of the drilling angle positioning plate, so as to fix the rotary plate and the L-shaped drill jig at the required deflection angle.

2. The machining tooling for the return oil inclined hole of the cooling oil of the diesel engine piston rod according to claim 1, characterized in that, 2 inclined drill sleeves symmetrically arranged with respect to the vertical center line of the vertical plate of the L-shaped drill jig are fixed on the vertical plate. The axis included angle 2α' of the 2 inclined drill sleeves matches the axis included angle 2α of the two inclined oil return inclined holes on the flat end face of the piston rod. The inner side face of the vertical plate is the reference surface, and one end of the horizontal support pin is respectively fixed on the vertical plate.

3. The machining tooling for the return oil inclined hole of the cooling oil of the diesel engine piston rod according to claim 2, wherein, The center distance X between the 2 horizontal support pins is less than the length A of the lower side plane of the flat end of the piston rod. The vertical distance Y between the center of the horizontal support pin and the center of the inclined drill sleeve is the sum of 1 / 2 of the flat end thickness B of the piston rod and the radius R of the horizontal support pin.

4. The machining tooling for the cooling oil return inclined hole of the diesel engine piston rod according to claim 1, characterized in that The center distance C1 of the rolling balls at the arc tops of the lower circular arc grooves of the 2 arc-shaped lower circular arc groove plates is greater than the center distance C2 of the double-headed bolts of the 2 sets of pressing components.

5. The machining tooling for the return oil inclined hole of the cooling oil of the diesel engine piston rod according to claim 1, characterized in that, Dust-proof plates are respectively arranged on both longitudinal sides of the rotary plate.

6. The machining tooling for the return oil inclined hole of the cooling oil of the diesel engine piston rod as described in claim 1, characterized in that, The difference between the height H1 of the drilling angle positioning plate and the height H2 of the support assembly: H1 - H2 = 0.10 - 0.20 mm.

7. A processing method using the processing tool for the oil return inclined hole of the diesel engine piston rod cooling oil as described in any one of claims 1 to 6, characterized in that, It includes the following steps: 1) Hoist the assembled processing tooling onto the machine tool workbench. After aligning the base plate, fix the base plate on the machine tool workbench. Then support the middle part of the piston rod to be processed on 2 V-shaped blocks, and make the flat end face of the piston rod to be processed abut against the reference surface on the inner side of the vertical plate of the L-shaped drill jig. The lower side plane of the flat end of the piston rod is supported on 2 horizontal support pins. Align the axis of the piston rod to be parallel to the axis of the machine tool spindle. Press the pressure plates on the middle part of the piston rod respectively, and tighten them on the double-headed bolts with the pressure plate nuts respectively, so that the piston rod is clamped and fixed in 2 sets of pressing assemblies. Finally, lock the machine tool workbench. 2) Rotate the rotary plate counterclockwise by an angle α, so that the longitudinal side of the rotary plate abuts against the outer edge of a vertical stop pin. Then pass the lower end of the precision bolt through the positioning pin hole at one corner of the rotary plate and screw it into the central threaded hole of a drilling angle positioning plate, so as to fix the rotary plate and the L-shaped drill jig at the required deflection angle of an oil return inclined hole. 3) Start the machine tool. The machine tool spindle drives the rotating drill bit to perform longitudinal feed. The drill bit drills into the flat end face of the piston rod under the guidance of the corresponding inclined drill bushing of the L-shaped drill jig. After drilling an oil return inclined hole with a depth of L in the flat end of the piston rod, withdraw the drill bit, and unscrew the precision bolt. The rotary plate is released from the fixed connection with the drilling angle positioning plate. 4) Rotate the rotary plate clockwise by an angle of 2α, so that the other longitudinal side of the rotary plate abuts against the outer edge of the corresponding vertical stop pin. Then pass the lower end of the precision bolt through the positioning pin hole at one corner of the rotary plate and screw it into the central threaded hole of another drilling angle positioning plate, so as to fix the rotary plate and the L-shaped drill jig at the required deflection angle of another oil return inclined hole. 5) Repeat the drilling process in step 3) to complete the drilling process of another oil return inclined hole with a depth of L in the flat end face of the piston rod.

8. The machining method of the machining tool for the return oil inclined hole of the cooling oil of the diesel engine piston rod according to claim 7, characterized in that, The drilling depth L of the oil return inclined hole = L1 + L2, L1 = 0.5(H - D) / sinα, L2 = 0.5d / tgα; where: H: The center distance of the oil return inclined hole; D: The diameter of the cooling oil pipe guiding hole to be bored; d: The diameter of the cooling oil return inclined hole; α: The angle between the axis of the cooling oil return inclined hole and the axis of the piston rod.

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