A drilling device and method for a square hole workpiece

Abstract

The present application belongs to the technical field of drilling processing, and discloses a drilling processing device and method for a square hole workpiece to solve the problems in the processing of the square hole workpiece in the prior art. The drilling processing device comprises a transmission shaft, a movable drill chuck is fitted and arranged at the lower part of the transmission shaft, the movable drill chuck comprises a movable drill sleeve and a drill chuck shell, the upper part of the movable drill sleeve is movably arranged in the inner cavity of the transmission shaft, a drill sleeve transmission plate is arranged at the lower part of the movable drill sleeve, a three-edged drill bit is arranged in the movable drill sleeve, a drill press clamp is arranged below the three-edged drill bit, a square drill sleeve is arranged at the top of the drill press clamp, a cam workpiece is arranged below the square drill sleeve, the three-edged drill bit moves around the center of the square drill sleeve while rotating to form a composite cutting track. When the cam workpiece is drilled, the three-edged drill bit rotates without centering, and the rotation and swing of the movable drill chuck form a composite cutting track in which the three-edged drill bit rotates while the center of the three-edged drill bit moves around the center of the square drill sleeve.

Description

Technical Field

[0001] This invention relates to the field of mechanical workpiece drilling technology, specifically to a drilling apparatus and method for a square hole workpiece. Background Technology

[0002] The transmission structure of a square shaft and a square hole is widely used in mechanical transmission structures. For example, the connection between the square shaft at the front end of the lever shaft and the square hole of the lever sleeve in ordinary gas triggers and electric triggers forms the output of rotational torque.

[0003] The connection between a square shaft and a square hole is also widely used in internal mechanical transmissions, such as the connection between the cam and planetary gear shaft in a high-torque pneumatic trigger. The square shaft of the planetary gear shaft can be machined using vertical milling. The square hole of the cam workpiece can be machined using various methods, such as planing, wire EDM, and hot stamping. Planing and wire EDM offer high machining accuracy but low efficiency. Hot stamping, on the other hand, offers low accuracy but high efficiency. Therefore, there is an urgent need to develop a machining process for square hole workpieces that offers both good machining accuracy and high efficiency. Summary of the Invention

[0004] In order to solve the technical problems existing in the machining of square holes in cam workpieces in the prior art, the present invention provides a drilling and machining device for square hole workpieces.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A drilling device for a square hole workpiece includes a drive shaft. A movable drill chuck, capable of rotation and oscillation, is fitted to the lower part of the drive shaft. The movable drill chuck includes a movable drill sleeve and a drill chuck housing mounted on the outer side of the lower part of the movable drill sleeve. The upper part of the movable drill sleeve is movably mounted inside the drive shaft. A drill sleeve drive plate is provided at the lower part of the movable drill sleeve. A movable block is installed between the drill sleeve drive plate and the bottom of the drive shaft. The top of the movable block is connected to the bottom of the drive shaft via a first steel ball, and the bottom of the movable block is connected to the top of the drill sleeve drive plate. Driven by a second steel ball, a triangular drill bit is installed inside the moving drill bushing. A drill press chuck is located below the triangular drill bit, and a square drill bushing is installed on top of the drill press chuck. A cam workpiece is located below the square drill bushing. The cam workpiece is limited by a limiting member installed on the drill press chuck. The triangular drill bit has a drill bit side cutting edge on the side near the cam workpiece, and a cutting bottom cutting edge is provided at the end of the drill bit side cutting edge. The drill bit side cutting edge is used to limit the square drill bushing, and the triangular drill bit moves around the center of the square drill bushing while rotating, forming a compound cutting trajectory.

[0007] Furthermore, the top of the moving block is symmetrically provided with first sliding grooves on both sides in the horizontal direction, and the bottom of the moving block is symmetrically provided with second sliding grooves on both sides in the vertical direction. The first sliding groove corresponds to the third sliding groove provided at the bottom of the drive shaft, and the second sliding groove corresponds to the fourth sliding groove provided at the top of the drill bushing drive plate. The first and third sliding grooves are used to install the first steel ball, and the second and fourth sliding grooves are used to install the second steel ball.

[0008] Furthermore, the bottom of the drive shaft is provided with a shoulder, the third sliding groove is opened at the bottom of the shoulder, the top of the drill chuck housing is threaded with a pressure plate, a first bearing is installed between the shoulder and the pressure plate, and a second bearing is installed between the bottom of the drill sleeve drive plate and the bottom of the drill chuck housing.

[0009] Furthermore, the drilling machine fixture includes a fixture body, which includes a fixture base plate. A fixture upright plate is fixed on the fixture base plate. The top of the fixture upright plate is used to install one side of the drill template, and the other side of the drill template is used to install the square drill bushing.

[0010] Furthermore, a positioning surface is provided on one side of the square drill bushing, and a baffle is provided at the positioning surface. The baffle can be detachably installed on the top surface of the drill template.

[0011] Furthermore, the limiting component includes a V-shaped positioning block, which is detachably installed on the side of the fixture upright plate. The V-shaped surface of the V-shaped positioning block contacts the side of the cam workpiece. A pressure plate is provided on the side of the cam workpiece away from the V-shaped surface. The pressure plate is detachably installed on the fixture upright plate via a long screw. A pressure block for limiting the cam workpiece is movably mounted on the pressure plate.

[0012] Furthermore, one end of the pressure plate is connected to the fixture upright plate via a first screw, and the other end of the pressure plate is connected to the fixture upright plate via a second screw.

[0013] Furthermore, both ends of the pressure plate are provided with pressure plate U-shaped connecting ears. The pressure plate U-shaped connecting ear at one end is connected to one end of the second screw through a first cylindrical pin. The other end of the second screw is connected to the fixture upright plate through a thread. The pressure plate U-shaped connecting ear at the other end is connected to one end of the first screw through a fastening nut. The other end of the first screw is connected to the upright plate U-shaped connecting ear provided at one end of the fixture upright plate through a second cylindrical pin.

[0014] Furthermore, the pressure plate has a mounting groove for mounting the pressure block in the middle of the side of the pressure plate near the cam workpiece, and the mounting groove and the pressure block are connected by a third cylindrical pin.

[0015] The present invention also discloses a drilling method for a square hole workpiece, which, using the above-mentioned drilling apparatus, further includes the following steps:

[0016] Step 1) First, place the drilling machine fixture on the worktable of the vertical drill Z512. After aligning the center of the square drill sleeve with the center of the drill spindle, fix the fixture base plate of the drilling machine fixture on the worktable of the drill machine.

[0017] Step 2) Connect the drive shaft, which is mounted with the moving drill chuck, to the drill press spindle;

[0018] Step 3) Then, insert the triangular drill bit into the traveling drill sleeve and place the cam workpiece into the drill press fixture for clamping and limiting;

[0019] Step 4) Slowly move the drill spindle down and introduce the triangular drill bit into the square drill sleeve, but at this time the cutting bottom edge does not contact the cutting end face of the cam workpiece;

[0020] Step 5) Start the drill spindle. The speed of the drill spindle is controlled between 120r / min and 200r / min. The rotation of the drill spindle drives the transmission shaft to rotate. The transmission shaft drives the floating drill chuck to rotate and swing. The floating drill sleeve drives the triangular drill bit to rotate. At the same time, the side edge of the drill bit is constrained by the four sides of the square drill sleeve, so that the triangular drill bit moves around the center of the square drill sleeve while rotating.

[0021] Step 6) Continue to move the drill spindle down to the cutting edge of the triangular drill bit to start cutting the end face of the cam workpiece. The main cutting rake angle of the cutting edge 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 is machined.

[0022] Step 7) Then slowly lift the drill spindle until the triangular cutting edge leaves the end face of the cam workpiece but does not leave the square drill sleeve. Stop the rotation of the drill spindle, remove the cam workpiece, and proceed to the next cam workpiece machining process.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] When the triangular drill bit of this invention drills a cam workpiece, it rotates non-centerably. Within the square drill sleeve, the rotation and oscillation of the floating drill chuck create a composite cutting trajectory where the triangular drill bit rotates while its center moves around the center of the square drill sleeve. The drive shaft, floating block, and floating drill sleeve of this invention are connected by a floating connection of a first steel ball and a second steel ball. As the floating drill sleeve drives the triangular drill bit to rotate, the center of the triangular drill bit continuously moves. The side cutting edge of the triangular drill bit rotates under the constraint of the square drill sleeve, and its center also moves, its trajectory being an approximately elliptical rotation around the center of the square drill sleeve.

[0025] This invention saves on the cost of purchasing wire EDM equipment, eliminates the need for wire EDM programming, and requires no workers with wire EDM operation skills. It only requires a standard vertical drilling machine and workers with drilling skills, significantly reducing labor costs while ensuring workpiece quality. Processing efficiency is increased by 150% compared to square hole boring and wire EDM; previously, an eight-hour shift processed 50 pieces, now it processes 125 pieces. Processing accuracy is improved by three levels compared to hot stamping.

[0026] The drilling machine fixture of the present invention provides U-shaped connecting ears for the pressure plate at both ends and U-shaped connecting ears for the vertical plate at one end of the fixture vertical plate, and makes the pressure plate detachable, which facilitates the removal of the workpiece. In addition, the V-shaped positioning block and the pressure block are installed in a detachable manner, which reduces the contact area with the cam workpiece, ensuring more reliable positioning and clamping, and making it easy to replace after wear.

[0027] This invention limits the movement of the square drill bushing by setting a baffle that contacts one of its positioning surfaces. The invention also limits the first bearing by using a clamping plate, and by providing a through hole in the clamping plate, it facilitates both tightening the plate and introducing lubricating oil. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0029] Figure 2 This is a schematic diagram of the structure of the movable drill clamp of the present invention.

[0030] Figure 3 This is a schematic diagram of the transmission shaft of the present invention.

[0031] Figure 4 This is a schematic diagram of the structure of the movable block of the present invention.

[0032] Figure 5 This is a schematic diagram of the structure of the triangular drill bit of the present invention.

[0033] Figure 6 This is a schematic diagram of the specific structure of the clamp of the present invention.

[0034] Figure 7 This is a front view of the drilling machine fixture of the present invention.

[0035] Figure 8 This is a top view of the drilling machine fixture of the present invention.

[0036] Figure 9 This is a schematic diagram of the structure of the V-shaped positioning block of the present invention.

[0037] Figure 10 This is a schematic diagram of the square drill sleeve of the present invention.

[0038] Figure 11 This is a schematic diagram of the drilling template of the present invention.

[0039] Figure 12 This is a schematic diagram of the structure of the pressure plate of the present invention.

[0040] Figure 13 This is a schematic diagram of the structure of the cam workpiece of the present invention.

[0041] Figure 14 This is a schematic diagram of the structure of the first screw of the present invention.

[0042] Figure 15 This is a schematic diagram of the rotation trajectory of the triangular drill bit of the present invention within the square drill sleeve.

[0043] Figure 16 This is a schematic diagram of the planetary gear shaft structure that mates with the cam workpiece of the present invention.

[0044] The meanings of the reference numerals in the attached drawings are as follows: 1. Drive shaft; 2. First steel ball; 3. Moving block; 4. Second steel ball; 5. Moving drill bushing; 6. Triangular drill bit; 7. Drill bit side cutting edge; 8. Square drill bushing; 9. Cutting bottom cutting edge; 10. V-shaped locating block; 11. Cam workpiece; 12. Vertical plate U-shaped connecting lug; 13. Fastening nut; 14. Fixture base plate; 15. First bearing; 16. Drill chuck housing; 17. Pressure plate; 18. Second bearing; 19. Sealing ring; 20. Drill bushing transmission plate; 21. First sliding... 21. Moving groove; 22. Second sliding groove; 23. Fixture upright plate; 24. Rib plate; 25. Pressure plate U-shaped connecting lug; 26. Second cylindrical pin; 27. Upright plate threaded hole; 28. Drill template; 29. ​​Third sliding groove; 30. Positioning block bolt; 31. First screw; 32. Pressure plate; 33. Pressure block; 34. Third cylindrical pin; 35. Baffle; 36. First cylindrical pin; 37. Second screw; 38. Positioning surface; 39. Shoulder; 40. Fourth sliding groove; 41. Through hole; 42. Mounting groove. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1-14As shown, a drilling device for a square hole workpiece includes a drive shaft 1. A movable drill chuck capable of rotation and oscillation is fitted to the lower part of the drive shaft 1. The movable drill chuck includes a movable drill sleeve 5 and a drill chuck housing 16. The drill chuck housing 16 is installed on the lower outer side of the movable drill sleeve 5 and the drive shaft 1. The upper part of the movable drill sleeve 5 is movably installed inside the drive shaft 1. A drill sleeve transmission plate 20 is provided at the lower part of the movable drill sleeve 5. 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 via 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 via a second steel ball 4. A second steel ball 4 is symmetrically arranged on both sides of the top of the movable block 3. A sliding groove 21 is provided, and a second sliding groove 22 is symmetrically provided on both sides of the bottom of the moving block 3. The first sliding groove 21 corresponds to the third sliding groove 29 provided at the bottom of the transmission shaft 1. The bottom of the transmission 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. The second sliding groove 22 corresponds to the fourth sliding groove 40 provided at the top of the drill bushing transmission plate 20. A second bearing 18 is installed between the bottom of the drill bushing transmission plate 20 and the bottom of the drill chuck housing 16. The first bearing 15 and the second bearing 18 are thrust ball bearings. A sealing ring 19 is installed between the lower part of the moving drill sleeve 5 and the drill chuck housing 16. The first sliding groove 21 and the third sliding groove 29 are used to install the first steel ball 2 (there are multiple first steel balls 2), and the second sliding groove 22 and the fourth sliding groove 40 are used to install the second steel ball 4 (there are multiple second steel balls 4).

[0047] The moving drill bushing 5 contains a triangular drill bit 6. Below the triangular drill bit 6 is a drill press fixture, which includes a fixture body and a fixture base plate 14. A fixture upright plate 23 is fixed to 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 bushing 8. One side of the square drill bushing 8 has a positioning surface 38, and a baffle 35 is provided at the positioning surface 38. The baffle 35 is detachably installed on the top surface of the drill template 28. A stiffening plate 24 is welded to the side of the fixture upright plate 23 away from the square drill bushing 8.

[0048] Below the square drill sleeve 8 is a cam workpiece 11. The cam workpiece 11 is limited by a limiting component mounted on the drill press fixture. The limiting component includes a V-shaped positioning block 10, which is mounted on the side of the fixture stand plate 23 by positioning block bolts 30. 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 by a first screw 31 and a second screw 37. The specific connection method is as follows: pressure plate Both ends of 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 threads (the clamping plate 23 is provided with a vertical plate threaded hole 27). The pressure plate U-shaped connecting ear 25 at the other end is connected to one end of the first screw 31 through the 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.

[0049] The pressure plate 32 has a mounting groove 42 in the middle of the side near the cam workpiece 11. The mounting groove 42 is used to mount the pressure block 33. The pressure block 33 is used to limit the cam workpiece 11. The mounting groove 42 and the pressure block 33 are movably connected by a third cylindrical pin 34.

[0050] The triangular drill bit 6 is provided with a drill bit side edge 7 on the side near the cam workpiece 11. The end of the drill bit side edge 7 is provided with a cutting bottom edge 9. The cutting bottom edge 9 is used to drill the cam workpiece 11. The drill bit side edge 7 is used to limit the position with 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.

[0051] A drilling method for a square hole workpiece, utilizing the aforementioned drilling apparatus, includes the following steps:

[0052] Step 1) First, place the drill jig on the worktable of the vertical drill Z512. After aligning the center of the square drill sleeve 8 with the center of the drill spindle, press the jig base plate 14 of the drill jig onto the worktable of the drill using two limiting plates.

[0053] Step 2) Connect the drive shaft 1, which is mounted with the moving drill chuck, to the drill press spindle.

[0054] Step 3) Then, the triangular drill bit 6 is installed into the moving drill sleeve 5, and the cam workpiece 11 is placed on the base plate 14 of the drill press fixture and pressed against the positioning surface of the V-shaped positioning block 10. Then, the pressure plate 32 is fixed to one side of the fixture vertical plate 23 by the first screw 31 and the second screw 37, and the cam workpiece 11 is pressed by the fastening nut 13, so that the cam workpiece 11 is positioned and clamped.

[0055] 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.

[0056] Step 5) Start the drill spindle. The speed of the drill spindle is controlled between 120r / min and 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 faces 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.

[0057] The drive shaft 1 drives the movable block 3 to rotate via the first steel ball 2. The movable block 3 drives the movable drill sleeve 5 to rotate via the second steel ball 4. Due to the torque transmitted through the first sliding groove 21 and second sliding groove 22 on both sides of the movable block 3 via the first steel ball 2 and second steel ball 4, displacement occurs simultaneously in the X and Y axes (there are gaps between the outer edge of the movable block 3 and the inner wall of the drill chuck housing 16, between the inner edge of the movable block 3 and the movable drill sleeve 5, between the inner edge of the drive shaft 1 and the outer edge of the movable drill sleeve 5, 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 housing 16, and between the clamping plate 17 and the drive shaft 1). The rotation of the movable drill sleeve 5 drives the triangular drill bit 6 to rotate. Under the constraint of the four faces of the square drill sleeve 8, the center of the triangular drill bit 6 is displaced when it rotates. This forms a machining trajectory, such as... Figure 15 As shown.

[0058] 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 machined.

[0059] 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 next cam workpiece 11 machining process.

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). The bottom of the movable block (3) is connected to the drill sleeve transmission plate (20) by a first steel ball (2). The top of the sliding block (20) is driven by a second steel ball (4). The top of the sliding block (3) is symmetrically provided with first sliding grooves (21) on both sides in the horizontal direction, and the bottom of the sliding block (3) is symmetrically provided with second sliding grooves (22) on both sides in the vertical direction. The first sliding groove (21) corresponds to the third sliding groove (29) provided at the bottom of the transmission shaft (1). The bottom of the transmission shaft (1) is provided with a shoulder (39). The third sliding groove (29) is opened at the bottom of the shoulder (39). 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). The top of the drill chuck housing (16) is threaded with a pressure plate (17), and the pressure plate (17) has a through hole (41). The shoulder (39) and the pressure plate (17) are fitted with a first bearing (15), and the bottom of the drill sleeve transmission plate (20) and the bottom of the drill chuck housing (16) are fitted with a second bearing (18). The moving drill sleeve (5) is fitted with a triangular drill bit (6). A drill press fixture is provided below the triangular drill bit (6), and a square drill sleeve (8) is mounted 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 mounted on the drill press fixture. The triangular drill bit (6) is provided with a drill bit side edge (7) on the side near the cam workpiece (11). The end of the drill bit side edge (7) is provided with 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 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).

3. The drilling apparatus for a square hole workpiece according to claim 2, 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).

4. The drilling apparatus for a square hole workpiece according to claim 3, 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).

5. The drilling apparatus for a square hole workpiece according to claim 4, 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).

6. The drilling apparatus for a square hole workpiece according to claim 5, 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).

7. The drilling apparatus for a square hole workpiece according to claim 4, 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).

8. A drilling method for a workpiece with a square hole, characterized in that, The drilling apparatus according to any one of claims 1-7 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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