Drilling machining device and method for square hole workpiece

Abstract

The invention belongs to the technical field of drilling machining, and discloses a drilling machining device and method for a square hole workpiece to solve the problems existing in square hole workpiece machining in the prior art. The drilling machining device comprises a transmission shaft, the lower portion of the transmission shaft is provided with a moving drill clamp in a matched mode, and the moving drill clamp comprises a moving drill sleeve and a drill clamp shell; the upper portion of the moving drill bushing is movably installed in an inner cavity of the transmission shaft, the lower portion of the moving drill bushing is provided with a drill bushing transmission plate, a three-edge drill bit is installed in the moving drill bushing, a drill jig is arranged below the three-edge drill bit, a square drill bushing is installed on the top of the drill jig, and a cam workpiece is arranged below the square drill bushing. The three-edge drill bit moves around the center of the square drill sleeve while rotating, and a composite cutting track is formed. When a cam workpiece is drilled, non-centering rotation is carried out, and a combined cutting track that the center of the three-edged drill bit moves around the center of the square drill sleeve while the three-edged drill bit rotates is formed in the square drill sleeve through rotation and swing of the moving drill clamp.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical workpiece drilling processing, in particular to a drilling processing device and method for a square hole workpiece. BACKGROUND

[0002] The transmission structure of the square shaft and the square hole is widely used in mechanical transmission structure, for example, the connection of the square shaft at the front end of the ordinary air wrench and the square hole of the wrench sleeve forms the output of the rotating torque.

[0003] The connection mode of the square shaft and the square hole is also widely used in the internal connection transmission of the machine, such as the connection of the cam and the planetary wheel shaft in the large-torque air wrench, which is the connection of the square hole and the square shaft. The square shaft of the planetary wheel shaft can be processed by the milling process, and the square hole of the cam workpiece can be processed by various processing methods, such as plunge cutting processing, wire electrical discharge machining, and hot stamping processing. The plunge cutting processing and the wire electrical discharge machining have high processing precision but low processing efficiency. The hot stamping processing method has low processing precision but high processing efficiency. Therefore, it is urgent to develop a square hole workpiece processing technology with good processing precision and high processing efficiency. SUMMARY

[0004] In order to solve the technical problems existing in the processing of the square hole of the cam workpiece in the prior art, the present application provides a drilling processing device for a square hole workpiece.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0006] A drilling processing device for a square hole workpiece, comprising a transmission shaft, a movable drill chuck capable of rotating and swinging is matched and installed at the lower part of the transmission shaft, the movable drill chuck comprises a movable drill sleeve and a drill chuck shell installed on the outer side of the lower part of the movable drill sleeve, the upper part of the movable drill sleeve is movably installed in the inner cavity of the transmission shaft, the lower part of the movable drill sleeve is provided with a drill sleeve transmission plate, a movable block is installed between the drill sleeve transmission plate and the bottom of the transmission shaft, the top of the movable block and the bottom of the transmission shaft are connected through a first steel ball transmission, the bottom of the movable block and the top of the drill sleeve transmission plate are connected through a second steel ball transmission, a three-edged drill bit is installed in the movable drill sleeve, a drill jig is arranged below the three-edged drill bit, a square drill sleeve is installed on the top of the drill jig, a cam workpiece is arranged below the square drill sleeve, the cam workpiece is limited by a limiting piece installed on the drill jig, a drill bit side edge is arranged on the side of the three-edged drill bit close to the cam workpiece, a cutting bottom edge is arranged on the end of the drill bit side edge, the drill bit side edge is used to limit the square drill sleeve, and the three-edged drill bit moves around the center of the square drill sleeve while rotating, forming a composite cutting track.

[0007] Further, the top of the floating block is symmetrically provided with first sliding grooves on both sides, the bottom of the floating block is symmetrically provided with second sliding grooves on both sides, the first sliding grooves correspond to third sliding grooves provided at the bottom of the transmission shaft, the second sliding grooves correspond to fourth sliding grooves provided at the top of the drill sleeve transmission plate, the first sliding grooves and the third sliding grooves are used for installing first steel balls, and the second sliding grooves and the fourth sliding grooves are used for installing second steel balls.

[0008] Further, the bottom of the transmission shaft is provided with a shaft shoulder, the third sliding grooves are opened at the bottom of the shaft shoulder, the drill clamp shell is threadedly provided with a pressing plate at the top, the first bearing is arranged between the shaft shoulder and the pressing plate, and the second bearing is arranged between the bottom of the drill sleeve transmission plate and the bottom of the drill clamp shell.

[0009] Further, the drill press clamp comprises a clamp body, the clamp body comprises a clamp bottom plate, a clamp vertical plate is fixed on the clamp bottom plate, one side of the top of the clamp vertical plate is used for installing a drill template, and the other side of the drill template is used for installing a four-square drill sleeve.

[0010] Further, one side of the four-square drill sleeve is provided with a positioning surface, a baffle is arranged at the positioning surface, and the baffle is detachably installed on the top surface of the drill template.

[0011] Further, the limiting piece comprises a V-shaped positioning block, the V-shaped positioning block is detachably installed on the side surface of the clamp vertical plate, the V-shaped surface of the V-shaped positioning block is in contact with the side surface of the cam workpiece, the side, away from the V-shaped surface, of the cam workpiece is provided with a pressing plate, the pressing plate is detachably installed on the clamp vertical plate through a long screw rod, and the pressing plate movably has a pressing block used for limiting the cam workpiece.

[0012] Further, one end of the pressing plate and the clamp vertical plate are connected through a first screw rod, and the other end of the pressing plate and the clamp vertical plate are connected through a second screw rod.

[0013] Further, both ends of the pressing plate are provided with pressing plate U-shaped connecting ears, the pressing plate U-shaped connecting ear at one end is connected with one end of the second screw rod through a first cylindrical pin, the other end of the second screw rod is connected with the clamp vertical plate through a thread, the pressing plate U-shaped connecting ear at the other end is connected with one end of the first screw rod through a fastening nut, and the other end of the first screw rod is connected with the vertical plate U-shaped connecting ear arranged at one end of the clamp vertical plate through a second cylindrical pin.

[0014] Further, the middle of the side of the pressing plate close to the cam workpiece is provided with a mounting groove used for installing the pressing block, and the mounting groove and the pressing block are connected through a third cylindrical pin.

[0015] The application further discloses a drilling machining method of the four-square hole workpiece, and utilizes the drilling machining device, and further comprises the following steps.

[0016] Step 1), first, the drill jig is placed on the workbench of the vertical drill Z512, the center of the four-square drill sleeve and the center of the drill spindle are aligned, and then the jig base plate of the drill jig is fixed on the workbench of the drill;

[0017] Step 2), then connect the transmission shaft installed with the movable drill clamp with the drill spindle;

[0018] Step 3), then install the three-edge drill bit into the movable drill sleeve, and clamp and limit the cam workpiece in the drill jig;

[0019] Step 4), slowly lower the drill spindle, and introduce the three-edge drill bit into the four-square drill sleeve, but the cutting bottom edge does not contact the cutting end surface of the cam workpiece at this time;

[0020] Step 5), start the drill spindle, the rotating speed of the drill spindle is controlled at 120r / min-200r / min, the drill spindle rotates to drive the transmission shaft to rotate, the transmission shaft drives the movable drill clamp to rotate and swing, the movable drill sleeve drives the three-edge drill bit to rotate, and at the same time, the three-edge drill bit moves around the center of the four-square drill sleeve while rotating under the constraint of the four surfaces of the four-square drill sleeve;

[0021] Step 6), continue to lower the drill spindle until the cutting bottom edge of the three-edge drill bit starts to cut the end surface of the cam workpiece, the main cutting rake angle of the cutting bottom edge is 0°, the relief angle is 5°, and the feed rate of the drill spindle is controlled at 0.1mm / r-0.2mm / r, and finally the four-square hole of the cam workpiece is machined;

[0022] Step 7), then slowly raise the drill spindle until the three-edge cutting bottom edge leaves the end surface of the cam workpiece, but is still in the four-square drill sleeve, stop the rotation of the drill spindle, take out the cam workpiece, and then enter the machining process of the next cam workpiece.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] When the three-edge drill bit drills the cam workpiece, it rotates without centering, and the rotation of the three-edge drill bit and the swing of the movable drill clamp form a composite cutting trajectory in which the center of the three-edge drill bit moves around the center of the four-square drill sleeve while rotating.

[0025] The present application saves the cost of purchasing electric spark wire cutting processing equipment, does not need electric spark wire cutting processing programming, does not need workers with electric spark wire cutting processing operation skills, only needs ordinary vertical drilling machines and workers with drilling processing skills, greatly reduces labor cost, guarantees workpiece quality, improves processing efficiency by 150% compared with square hole broaching processing and electric spark wire cutting processing, processes 50 pieces in one eight-hour work shift, and processes 125 pieces in one eight-hour work shift now.

[0026] The drilling machine clamp of the present application is detachably connected with the pressing plate through the pressing plate U-shaped connecting ears at both ends of the pressing plate and the stand plate U-shaped connecting ears at one end of the stand plate, so that the workpiece can be conveniently taken out, and the V-shaped positioning block and the pressing block are detachably installed, so that the contact area with the cam workpiece can be reduced, the positioning and pressing can be more reliable, and the V-shaped positioning block and the pressing block can be conveniently replaced after wear.

[0027] The present application limits the four-square drill sleeve through the contact with the positioning surface of one side of the four-square drill sleeve, and prevents the four-square drill sleeve from moving. The first bearing is limited by the pressing plate, and the through hole is arranged on the pressing plate, which is convenient for screwing the pressing plate and passing in lubricating oil. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present application.

[0029] Figure 2 It is a schematic diagram of the structure of the present application.

[0030] Figure 3 It is a schematic diagram of the structure of the present application.

[0031] Figure 4 It is a schematic diagram of the structure of the present application.

[0032] Figure 5 It is a schematic diagram of the structure of the present application.

[0033] Figure 6 It is a schematic diagram of the structure of the present application.

[0034] Figure 7 It is a front view of the drilling machine clamp of the present application.

[0035] Figure 8 It is a top view of the drilling machine clamp of the present application.

[0036] Figure 9 It is a schematic diagram of the structure of the present application.

[0037] Figure 10 It is a schematic diagram of the structure of the present application.

[0038] Figure 11 The structure diagram of the drill jig plate of the present application.

[0039] Figure 12 The structure diagram of the pressing plate of the present application.

[0040] Figure 13 The structure diagram of the cam workpiece of the present application.

[0041] Figure 14 The structure diagram of the first screw rod of the present application.

[0042] Figure 15 The rotating track diagram of the three-edge drill bit in the square drill sleeve of the present application.

[0043] Figure 16 The structure diagram of the planetary wheel shaft matched with the cam workpiece of the present application.

[0044] The meanings of the reference signs are as follows: 1. transmission shaft; 2. first steel ball; 3. floating block; 4. second steel ball; 5. floating drill sleeve; 6. three-edge drill bit; 7. drill bit side blade; 8. square drill sleeve; 9. cutting bottom blade; 10. V-shaped positioning block; 11. cam workpiece; 12. vertical plate U-shaped connecting lug; 13. fastening nut; 14. clamp bottom plate; 15. first bearing; 16. drill clamp shell; 17. pressing plate; 18. second bearing; 19. sealing ring; 20. drill sleeve transmission plate; 21. first sliding groove; 22. second sliding groove; 23. clamp vertical plate; 24. rib plate; 25. pressing plate U-shaped connecting lug; 26. second cylindrical pin; 27. vertical plate threaded hole; 28. drill jig plate; 29. third sliding groove; 30. positioning block bolt; 31. first screw rod; 32. pressing plate; 33. pressing block; 34. third cylindrical pin; 35. baffle; 36. first cylindrical pin; 37. second screw rod; 38. positioning surface; 39. shaft shoulder; 40. fourth sliding groove; 41. through hole; 42. mounting groove. DETAILED DESCRIPTION

[0045] The present application will be further described below in combination with the drawings and specific embodiments.

[0046] As Figures 1-14As shown, a kind of drilling device of square hole workpiece, including transmission shaft 1, the lower part of transmission shaft 1 is matched with the movable drill chuck that can realize rotation and swing, movable drill chuck includes movable drill sleeve 5 and drill chuck shell 16, drill chuck shell 16 is installed in movable drill sleeve 5 and the lower part outside of transmission shaft 1, the upper part of movable drill sleeve 5 is movably installed in the inner cavity of transmission shaft 1, the lower part of movable drill sleeve 5 is equipped with drill sleeve transmission plate 20, movable block 3 is equipped between drill sleeve transmission plate 20 and the bottom of transmission shaft 1, the top of movable block 3 and the bottom of transmission shaft 1 are driven through first steel ball 2, the bottom of movable block 3 and the top of drill sleeve transmission plate 20 are driven through second steel ball 4, the top of movable block 3 is equipped with the first sliding groove 21 that is symmetrical to the lateral two sides, the bottom of movable block 3 is equipped with the second sliding groove 22 that is symmetrical to the longitudinal two sides, the first sliding groove 21 corresponds with the third sliding groove 29 being arranged in the bottom of transmission shaft 1, and the bottom of transmission shaft 1 is equipped with shaft shoulder 39, the third sliding groove 29 is opened in the bottom of shaft shoulder 39, the top of drill chuck shell 16 is equipped with the threaded press plate 17, the through hole 41 is opened in press plate 17, the first bearing 15 is equipped between shaft shoulder 39 and press plate 17, the second sliding groove 22 corresponds with the fourth sliding groove 40 being arranged in the top of drill sleeve transmission plate 20, and the second bearing 18 is equipped between the bottom of drill sleeve transmission plate 20 and the bottom of drill chuck shell 16, first bearing 15 and second bearing 18 are thrust ball bearings. The lower part between movable drill sleeve 5 and drill chuck shell 16 is equipped with sealing ring 19, first sliding groove 21, third sliding groove 29 are used to install first steel ball 2 (first steel ball 2 is multiple), second sliding groove 22, fourth sliding groove 40 are used to install second steel ball 4 (second steel ball 4 is multiple).

[0047] Movable drill sleeve 5 is equipped with three-edged drill bit 6, drill bed clamp is equipped below three-edged drill bit 6, and drill bed clamp includes clamp body, and the clamp body includes clamp bottom plate 14, clamp bottom plate 14 is fixed with clamp vertical plate 23, the top of clamp vertical plate 23 is used to install one side of drill template plate 28, the other side of drill template plate 28 is used to install square drill sleeve 8, one side of square drill sleeve 8 is equipped with positioning surface 38, baffle 35 is equipped at positioning surface 38, and baffle 35 is detachably installed on the top surface of drill template plate 28.The side of clamp vertical plate 23 away from square drill sleeve 8 is welded with web plate 24.

[0048] Below the four square drill bushing 8 is provided with cam workpiece 11, cam workpiece 11 is limited by installing the limit piece on the drill jig, the limit piece includes V type positioning block 10, the V type positioning block 10 is installed on the side of the jig vertical plate 23 by positioning block bolt 30, and the V type surface of the V type positioning block 10 is in contact with the side surface of the cam workpiece 11, the side of the cam workpiece 11 away from the V type surface is provided with the pressing plate 32, the pressing plate 32 is detachably installed with the jig vertical plate 23 through the first screw rod 31, the second screw rod 37, and the specific connection mode is: the both ends of the pressing plate 32 are provided with the pressing plate U type connecting lug 25, the pressing plate U type connecting lug 25 at one end is connected with one end of the second screw rod 37 through the first cylindrical pin 36, the other end of the second screw rod 37 is connected with the jig vertical plate 23 through the thread (the jig vertical plate 23 is provided with the vertical plate threaded hole 27), the other end of the pressing plate U type connecting lug 25 is connected with one end of the first screw rod 31 through the locking nut 13, and the other end of the first screw rod 31 is connected with the vertical plate U type connecting lug 12 provided at one end of the jig vertical plate 23 through the second cylindrical pin 26.

[0049] The middle part of the side of the pressing plate 32 close to the cam workpiece 11 is provided with the installation groove 42, the installation groove 42 is used for installing the pressing block 33, the pressing block 33 is used for limiting the cam workpiece 11, and the installation groove 42 is movably connected with the pressing block 33 through the third cylindrical pin 34.

[0050] The side of the three edge drill bit 6 close to the cam workpiece 11 is provided with the drill bit side blade 7, the end of the drill bit side blade 7 is provided with the cutting bottom blade 9, the cutting bottom blade 9 is used for drilling the cam workpiece 11, the drill bit side blade 7 is used for limiting the four square drill bushing 8, and the three edge drill bit 6 moves around the center of the four square drill bushing 8 while rotating, forming a composite cutting trajectory.

[0051] A kind of four square hole workpiece drilling processing method, utilizes the drilling processing device described above, including the following steps:

[0052] Step 1), first, drill jig is placed into the workbench surface of vertical drill Z512, after the center of four square drill bushing 8 and drill spindle center are aligned coaxially, the jig base plate 14 of drill jig is pressed in the workbench surface of drill by two limit plates.

[0053] Step 2), then, transmission shaft 1 installed with movable drill clamp is connected with drill spindle.

[0054] Step 3), then, three edge drill bit 6 is installed into movable drill bushing 5, and cam workpiece 11 is placed into the jig base plate 14 of drill jig and close to the positioning surface of V type positioning block 10, then, pressing plate 32 is fixed in one side of jig vertical plate 23 through first screw rod 31 and second screw rod 37, and cam workpiece 11 is compacted by locking nut 13, so that cam workpiece 11 is positioned and clamped.

[0055] Step 4), slowly lower the main shaft of the drilling machine, and introduce the three-edge drill bit 6 into the square drill sleeve 8, but the cutting bottom edge 9 does not contact the cutting end face of the cam workpiece 11 at this time.

[0056] Step 5), start the main shaft of the drilling machine, control the rotation speed of the main shaft of the drilling machine at 120r / min-200r / min, the rotation of the main shaft of the drilling machine drives the rotation of the transmission shaft 1, the transmission shaft 1 drives the rotating and swinging movement of the movable drill chuck, the movable drill sleeve 5 drives the rotation of the three-edge drill bit 6, and at the same time, the three-edge drill bit 6 moves around the center of the square drill sleeve 8 while rotating under the constraint of the four sides of the square drill sleeve 8.

[0057] The transmission shaft 1 drives the rotation of the movable block 3 through the first steel ball 2, and the movable block 3 drives the rotation of the movable drill sleeve 5 through the second steel ball 4. Since the first sliding groove 21 and the second sliding groove 22 on the two sides of the movable block 3 transmit torque through the first steel ball 2 and the second steel ball 4, displacement is generated in the X-axis and the Y-axis (there is a gap between the outer edge of the movable block 3 and the inner wall of the drill chuck shell 16, there is a gap between the inner edge of the movable block 3 and the movable drill sleeve 5, there is a gap between the inner edge of the transmission shaft 1 and the outer edge of the movable drill sleeve 5, there is a gap between the outer edge of the drill sleeve transmission plate 20 of the movable drill sleeve 5 and the inner wall of the drill chuck shell 16, and there is a gap between the compression plate 17 and the transmission shaft 1). The rotation of the movable drill sleeve 5 drives the rotation of the three-edge drill bit 6, and the three-edge drill bit 6 moves in the center when rotating under the constraint of the four sides of the square drill sleeve 8. The formed machining track is as shown in Figure 15 .

[0058] Step 6), continue to lower the main shaft of the drilling machine until the cutting bottom edge 9 of the three-edge drill bit 6 starts to cut the end face of the cam workpiece 11, the main cutting rake angle of the cutting bottom edge 9 is 0°, the relief angle is 5°, the feed rate of the main shaft of the drilling machine is controlled at 0.1mm / r-0.2mm / r, and finally the square hole machining of the cam workpiece 11 is completed.

[0059] Step 7), then slowly raise the main shaft of the drilling machine until the three-edge cutting bottom edge 9 leaves the end face of the cam workpiece 11, but does not leave the square drill sleeve 8, stop the rotation of the main shaft of the drilling machine, take out the cam workpiece 11, and then enter the machining process of the next cam workpiece 11.

Claims

1. A drilling device for a square hole workpiece, comprising a drive shaft (1), characterized in that: The lower part of the drive shaft (1) is fitted with a movable drill chuck that can rotate and swing. The movable drill chuck includes a movable drill sleeve (5) and a drill chuck housing (16) installed on the lower outer side of the movable drill sleeve (5). The upper part of the movable drill sleeve (5) is movably installed in the inner cavity of the drive shaft (1). The lower part of the movable drill sleeve (5) is provided with a drill sleeve transmission plate (20). A movable block (3) is installed between the drill sleeve transmission plate (20) and the bottom of the drive shaft (1). The top of the movable block (3) is connected to the bottom of the drive shaft (1) by a first steel ball (2), and the bottom of the movable block (3) is connected to the top of the drill sleeve transmission plate (20) by a second steel ball (4). The moving drill sleeve (5) contains a triangular drill bit (6), and a drill press fixture is provided below the triangular drill bit (6). A square drill sleeve (8) is provided on the top of the drill press fixture. A cam workpiece (11) is provided below the square drill sleeve (8). The cam workpiece (11) is limited by a limiting member installed on the drill press fixture. The triangular drill bit (6) has a drill bit side edge (7) on the side near the cam workpiece (11). The end of the drill bit side edge (7) has a cutting bottom edge (9). The drill bit side edge (7) is used to limit the square drill sleeve (8). The triangular drill bit (6) moves around the center of the square drill sleeve (8) while rotating, forming a compound cutting trajectory.

2. The drilling apparatus for a square hole workpiece according to claim 1, characterized in that: The top of the moving block (3) is symmetrically provided with a first sliding groove (21) on both sides of the horizontal direction, and the bottom of the moving block (3) is symmetrically provided with a second sliding groove (22) on both sides of the vertical direction. The first sliding groove (21) corresponds to the third sliding groove (29) provided at the bottom of the transmission shaft (1), and the second sliding groove (22) corresponds to the fourth sliding groove (40) provided at the top of the drill bushing transmission plate (20). The first sliding groove (21) and the third sliding groove (29) are used to install the first steel ball (2), and the second sliding groove (22) and the fourth sliding groove (40) are used to install the second steel ball (4).

3. The drilling apparatus for a square hole workpiece according to claim 2, characterized in that: The bottom of the drive shaft (1) is provided with a shoulder (39), the third sliding groove (29) is opened at the bottom of the shoulder (39), the top of the drill chuck housing (16) is threaded with a pressure plate (17), the pressure plate (17) is provided with a through hole (41), a first bearing (15) is installed between the shoulder (39) and the pressure plate (17), and a second bearing (18) is installed between the bottom of the drill bushing drive plate (20) and the bottom of the drill chuck housing (16).

4. The drilling apparatus for a square hole workpiece according to claim 3, characterized in that: The drilling machine fixture includes a fixture body, which includes a fixture base plate (14). A fixture upright plate (23) is fixed on the fixture base plate (14). The top of the fixture upright plate (23) is used to install one side of the drill template (28), and the other side of the drill template (28) is used to install the square drill sleeve (8).

5. The drilling apparatus for a square hole workpiece according to claim 4, characterized in that: The square drill sleeve (8) has a positioning surface (38) on one side, and a baffle (35) is provided at the positioning surface (38). The baffle (35) can be detachably installed on the top surface of the drill template (28).

6. The drilling apparatus for a square hole workpiece according to claim 5, characterized in that: The limiting component includes a V-shaped positioning block (10), which is detachably installed on the side of the fixture stand plate (23). The V-shaped surface of the V-shaped positioning block (10) contacts the side of the cam workpiece (11). A pressure plate (32) is provided on the side of the cam workpiece (11) away from the V-shaped surface. The pressure plate (32) is detachably installed on the fixture stand plate (23) through a long screw. A pressure block (33) for limiting the cam workpiece (11) is movably mounted on the pressure plate (32).

7. The drilling apparatus for a square hole workpiece according to claim 6, characterized in that: One end of the pressure plate (32) is connected to the clamping plate (23) by a first screw (31), and the other end of the pressure plate (32) is connected to the clamping plate (23) by a second screw (37).

8. The drilling apparatus for a square hole workpiece according to claim 7, characterized in that: Both ends of the pressure plate (32) are provided with pressure plate U-shaped connecting ears (25). The pressure plate U-shaped connecting ear (25) at one end is connected to one end of the second screw (37) through the first cylindrical pin (36). The other end of the second screw (37) is connected to the clamping plate (23) through a thread. The pressure plate U-shaped connecting ear (25) at the other end is connected to one end of the first screw (31) through a fastening nut (13). The other end of the first screw (31) is connected to the vertical plate U-shaped connecting ear (12) provided at one end of the clamping plate (23) through the second cylindrical pin (26).

9. The drilling apparatus for a square hole workpiece according to claim 6, characterized in that: The pressure plate (32) has a mounting groove (42) for mounting the pressure block (33) in the middle of the side near the cam workpiece (11), and the mounting groove (42) and the pressure block (33) are connected by a third cylindrical pin (34).

10. A drilling method for a workpiece with a square hole, characterized in that, The drilling apparatus according to any one of claims 1-9 further includes the following steps: Step 1) First, place the drill fixture on the worktable of the vertical drill Z512, align the center of the square drill sleeve (8) with the center of the drill spindle, and then fix the base plate (14) of the drill fixture on the worktable of the drill. Step 2) Connect the drive shaft (1) that is mounted with the moving drill chuck to the drill press spindle; Step 3) Then, the triangular drill bit (6) is inserted into the moving drill sleeve (5), and the cam workpiece (11) is placed into the drill press fixture for clamping and limiting. Step 4) Slowly move the drill spindle down and introduce the triangular drill bit (6) into the square drill sleeve (8), but at this time the cutting bottom edge (9) does not contact the cutting end face of the cam workpiece (11); Step 5) Start the drill spindle. The speed of the drill spindle is controlled at 120r / min-200r / min. The rotation of the drill spindle drives the transmission shaft (1) to rotate. The transmission shaft (1) drives the floating drill chuck to rotate and swing. The floating drill sleeve (5) drives the triangular drill bit (6) to rotate. At the same time, the drill bit side edge (7) is constrained by the four sides of the square drill sleeve (8), so that the triangular drill bit (6) moves around the center of the square drill sleeve (8) while rotating. Step 6) Continue to move the drill spindle down to the cutting edge (9) of the triangular drill bit (6) to start cutting the end face of the cam workpiece (11). The main cutting rake angle of the cutting edge (9) is 0° and the clearance angle is 5°. The feed rate of the drill spindle is controlled at 0.1mm / r-0.2mm / r. Finally, the square hole of the cam workpiece (11) is cut and the machining is completed. Step 7) Then slowly lift the drill spindle until the triangular cutting edge (9) leaves the end face of the cam workpiece (11) but does not leave the square drill sleeve (8). Stop the rotation of the drill spindle, take out the cam workpiece (11), and then proceed to the machining process of the next cam workpiece (11).

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