Drilling tool and drilling method of long overhanging gun drill

Abstract

The invention discloses a drilling tool and a drilling method of a long overhanging gun drill. The drilling method comprises the step of machining an outer circle, two end faces and an inner hole of a tubular workpiece. An annular groove is turned in the outer wall of the middle of a tubular workpiece, and the outer wall is divided into a guide part for guiding drilling and a large-diameter shaft needing to be drilled with an axial deep hole. A guide through hole is drilled in the guide part in the axial direction. And a drilling tool is mounted on the circular ring groove. A drill bit penetrates through the guide part and the guide through hole of the drilling tool, and a deep hole is machined in the step face between the outer circle section and the annular groove. And the guide part is removed, and machining of the tubular workpiece is completed. The positioning component integrated with the tubular workpiece is obtained through the guide part temporarily reserved in the machining process, auxiliary positioning of the gun drill is achieved through the reserved left end through hole and the drilling tool clamped on the annular groove, vibration generated by overhanging of a drill bit is effectively reduced, errors caused by overhanging of the drill bit during gun drilling are avoided, and the machining precision is improved. And the machining precision and efficiency are improved.

Description

Technical Field

[0001] The invention relates to the field of drilling technology and machining auxiliary tools for mechanical parts, in particular to a drilling tool and a drilling method for a long overhang gun drill. Background Art

[0002] In mechanical processing, deep hole processing is a process with high technical requirements. Especially when deep holes need to be processed on the stepped section of a long tubular part, the gun drill bit needs to drill along the length of the tubular part, and due to the superposition of the length of the tubular part itself and the length of the deep hole itself, the drill bit protrudes too far from the gun head, causing the drill bit to easily vibrate during the drilling process, thereby affecting the processing accuracy and efficiency. The existing deep hole processing methods do not have auxiliary tooling and methods for this type of structure, and often rely on the operator's experience and skills; if there is no positioning device, it is difficult to ensure the precise positioning and guidance of the drill bit during the processing, affecting the quality of the product; and the scrap rate of raw materials will increase, increasing the manufacturing cost. Summary of the invention

[0003] The present invention aims to solve the problems of poor precision, low efficiency and high cost caused by excessively long rotation extension of a drill bit, and to provide a drilling tool and a drilling method for a long overhang gun drill.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the present invention provides a drilling tool for a long overhang gun drill, including an upper block and a lower block, each of which is provided with a notch, and the notches are closed to form a mounting hole; the upper block is also provided with a plurality of guide through holes for guiding the gun drill.

[0005] Among them, the five guide through holes are arranged along the circumferential direction.

[0006] The five guide through holes are arranged in a circular arc with a circumferential angle of 75°.

[0007] The penetration end of the guide through hole is provided with a bell mouth, that is, the diameter at the hole mouth is larger than the diameter of the first-order guide hole, and the transition is completed through a conical surface arranged on the inner wall.

[0008] The notch is semicircular and after being butted together, forms a circular hole corresponding to the shape of the notch at the fixed position on the tubular workpiece.

[0009] Wherein, the diameter of the circular hole is slightly larger than the diameter of the position where it is fixed.

[0010] Among them, there are two symmetrical step holes at the two ends of the upper block; there are two threaded holes at the two ends of the lower block, and the threaded holes correspond to the step holes of the upper block respectively; the bolts are inserted and tightened to complete the fixed connection.

[0011] The upper end surface of the upper block is provided with a flat plate for calibration.

[0012] The technical solution of the present invention also provides a method for drilling a stepped surface of a tubular workpiece, comprising:

[0013] Step 1: Processing the outer circle, two end faces and inner hole of the tubular workpiece according to the raw material;

[0014] Step 2: a circular groove is machined on the outer wall of the middle part of the tubular workpiece, and the outer wall is divided into a guide part (shorter axial length) for fixing and drilling guidance, and a large diameter shaft (longer axial length) on the side wall where an axial deep hole needs to be drilled from the step surface;

[0015] Step three, drilling a plurality of guide through holes along the axial direction on the guide portion.

[0016] Step 4: Install a number of drilling tools as described above on the annular groove.

[0017] Step 5: The drill bit passes through the guide part and several guide through holes on the drilling tool respectively, and processes several corresponding deep holes on the stepped surface between the outer circle segment and the annular groove.

[0018] Step six, remove the guide part to complete the processing of the tubular workpiece.

[0019] In step 3, a calibration block is also set on the outer wall of the tubular workpiece as a calibration reference in the circumferential direction. The cross section of the calibration block is rectangular, and a workpiece flat parallel to the upper surface of the calibration block is machined on the guide portion and used for calibration with the flat of the upper block of the drilling tool in step 4.

[0020] Among them, in step five, after drilling one side of a plurality of deep holes on the stepped surface, the drilling tool is removed; then the tubular workpiece is turned around and the drilling on the other side is completed; thus, a complete through deep hole is formed.

[0021] Compared with the prior art, the present invention obtains a positioning component integrated with the tubular workpiece through the guide portion temporarily retained during the processing, and utilizes the reserved left-end through hole and the drilling tooling clamped on the annular groove to achieve auxiliary positioning of the gun drill, effectively reducing the vibration caused by the excessive overhang of the drill bit, avoiding the error caused by the excessive overhang during gun drilling, and improving the processing accuracy and efficiency.

[0022] The guide hole of the drilling tool has a beveled flare at the end, which provides a stable guide for the drill bit and further ensures the accuracy of drilling. The reference block on the workpiece is level with the positioning reference on the end face of the drilling tool, and the strict coaxiality and parallelism requirements in each step jointly ensure the high precision of processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a front view of the structural schematic diagram of the drilling tooling of the long overhang gun drill.

[0024] Figure 2 for Figure 1 Section view of the AA plane.

[0025] Figure 3 This is the front view of the semi-finished gun-drilled pipe fitting with long overhang.

[0026] Figure 4 for Figure 1 Cross-sectional view of the middle BB plane.

[0027] Figure 5 The figure is a schematic diagram of drilling installation using the drilling tool of the present invention.

[0028] Figure 6 Schematic diagram of the finished gun drilled pipe with long overhang.

[0029] In the figure: 1: upper block; 2: lower block; 3: guide through hole; 4: step hole; 5: threaded hole; 6: inner ring; 7: flat type; 8: bell mouth; 100: tubular workpiece; 101: correction block; 102 workpiece flat type; 103: left end through hole: 104: circular ring groove; 105: deep hole. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the drilling tool and hole processing method of the long overhang gun drill of the present invention clearer, the present invention will be further described in detail with reference to the accompanying drawings. For the convenience of description, the direction along the central axis of the tubular workpiece pointing to the guide part is referred to as "left", and the opposite direction is referred to as "right", that is, the accompanying drawings of the present invention are used as a reference, but they cannot be used as a limitation of the present invention.

[0031] See also Figure 1 and Figure 2 , Figure 1 and Figure 2 What is shown is an embodiment of the present invention, a drilling tool for a long overhang gun drill, which is a split thin cylinder with an axial opening, including an upper block and a lower block, each of which is provided with a semicircular notch, and the notches are butted together to form a circular hole (circular inner ring) corresponding to the shape of the fixed position (circular groove / small diameter shaft) on the tubular workpiece; the thickness of the upper block and the lower block is 40mm. Preferably, the diameter of the circular hole is slightly larger than the diameter of the fixed position.

[0032] See also Figure 1 The upper block is also provided with a number of guide holes for guiding the gun drill. In this embodiment, according to the needs of parts processing, the upper block is provided with five penetrating guide holes with a hole diameter of 6.35 mm. The five holes are arranged along the circumference and form a fan-shaped arrangement with a circumferential angle of 75°.

[0033] Further, see Figure 2The opening of the left penetration end of the guide through hole has a bevel / bell mouth, that is, the diameter at the hole mouth is larger than the diameter of the first-order guide hole, and the transition is completed by a conical surface arranged on the inner wall. The setting of the bell mouth can make the drill bit more stable during the penetration process, which is conducive to improving the accuracy.

[0034] Furthermore, the openings on both sides of the guide through hole should maintain sharp edges to ensure that the drill bit cannot pass through when the hole is not aligned with the position.

[0035] Further, see Figure 1 There are two symmetrical step holes at both ends of the upper block; there are two threaded holes at both ends of the lower block, which correspond to the step holes of the upper block respectively; when installing, two bolts are inserted into the step holes and threaded holes and tightened to complete the fixed connection, and then put on the tubular workpiece.

[0036] Further, see Figure 2 The upper end surface of the upper block is provided with a flat type for calibration, which is a step / plane structure and is used as a positioning reference plane. The positioning reference depth of the upper end surface of the upper block is 5mm and is flush with the reference block on the tubular workpiece to be drilled.

[0037] See also Figure 4 and Figure 6 Another embodiment of the present invention implements a method for drilling a stepped surface of a tubular workpiece based on the above-mentioned drilling tool. The processing object is a tubular workpiece with a long overhang gun drill. The tubular workpiece is divided into a small diameter shaft with a smaller diameter on the left and a large diameter shaft with a larger diameter on the right. There is a stepped surface at the boundary between the large diameter shaft and the small diameter shaft, and the stepped surface is a circular ring. The tubular workpiece needs to be processed with a deep hole along the center axis on the stepped surface by a drill bit, and the deep hole penetrates from the stepped surface to the right end surface of the tubular workpiece.

[0038] Step 1: Process the outer circle, two end faces and inner hole of the tubular workpiece according to the raw material. Semi-finish turning the two end faces of the tubular raw material and the 200mm left and right ends of the outer circle are used as the subsequent processing reference; then, using the outer circle as the reference, drill, expand and bore the inner holes that penetrate the two end faces of the tubular workpiece.

[0039] Step 2: Based on the outer circle turned in step 1, a circular annular groove and two end faces of the tubular workpiece are roughly turned on the middle outer wall; based on the inner hole, the outer circle, the circular annular groove and the total length of the two end faces are semi-finished.

[0040] The diameter of the annular groove is equal to the small diameter shaft. Since it is located in the middle, the outer wall of the tubular workpiece is divided into a guide part and a large diameter shaft. Among them, the guide part located at the left end of the tubular workpiece is a section of annular column structure temporarily retained during the processing. Its diameter is the same as the outer circle and the large diameter shaft. It is used as a guide part for fixing and drilling guidance. The large diameter shaft is part of the final form of the tubular workpiece, that is, an axial deep hole needs to be drilled on its side wall. Step 3: See Figure 4 and Figure 5 , glue the correction block to the outer wall of the right end of the large diameter shaft, and mill the correction surface on the upper end of the correction block. Take the left end of the inner hole of the tubular workpiece as the reference to find the positive coordinate position. Then drill and mill the left end through hole and the workpiece flat on the guide part; see Figure 3 , the flat surface of the workpiece is parallel to the upper correction surface of the correction block.

[0041] Step 4: Use a support pad to support the tubular workpiece and keep the correction block facing upward; correct the flatness of the workpiece in step 3, so as to align the five left through holes on the left end surface. Then, install the drilling tool in the above embodiment of the present invention on the annular groove.

[0042] See Figure 5 , the specific installation method is as follows:

[0043] Place the upper block and the lower block above and below the middle of the circular groove respectively, and visually check the middle without being precise to the midpoint. Since the diameters of the upper block and the lower block are slightly larger than the diameter of the circular groove, and part of the thickness of the upper block 1 and the lower block 2 will be consumed during cutting, the inner ring of the tooling can fit the circular groove.

[0044] Then use two M10 bolts to pass through the step hole and the threaded hole in turn and tighten them to semi-pretightening. The tightening degree is that it will not rotate with vibration or small force, but can rotate with a little force.

[0045] Then, the flatness of the upper end of the upper block is corrected through the flatness of the workpiece at the left end of the tubular workpiece, so that the parallelism between the two planes is less than 0.01; then verify whether the five left end through holes of the guide part correspond to the five through holes on the upper block.

[0046] Step 5: Use the five left through holes on the left end face of the tubular workpiece and the five through holes on the drilling tool as drilling guides, let the drill bit pass through in sequence, and drill five holes (half the length) on the stepped surface of the tubular workpiece; after completion, remove the drilling tool; then turn the tubular workpiece around, calibrate the drilling position of the workpiece with the correction block, complete the drilling on the other side (the other half the length), form a complete through deep hole, and check whether the drilling position is qualified.

[0047] Step 6: Remove the correction block on the outer wall of the tubular workpiece, and then semi-finish the guide part on the left end to reduce its diameter and make it part of the small-diameter shaft. The final result is as follows: Figure 6 As shown. The processing of the tubular workpiece is now completed. This embodiment achieves high-precision gun drilling for long overhang gun drilling at a low cost, which can be achieved on a horizontal machining center, effectively reducing the vibration caused by the overhang of the drill bit, improving the processing accuracy, ensuring the processing efficiency, and improving the production benefits.

Claims

1. A drilling tool for a long overhang gun drill, characterized in that: It comprises an upper block and a lower block, each of which is provided with a notch, and the notches are closed to form a mounting hole; The upper block is also provided with a plurality of guide through holes for guiding the gun drill.

2. The drilling tool according to claim 1, characterized in that: The five guide through holes are arranged along the circumferential direction, and / or the five guide through holes are arranged in a fan shape with a circumferential angle of 75°.

3. The drilling tool according to claim 2, characterized in that: The penetration end of the guide through hole is provided with a bell mouth.

4. The drilling tool according to claim 1, characterized in that: The notch is semicircular and, after being butted together, forms a circular hole corresponding to the shape of the fixed position on the tubular workpiece; and / or the diameter of the circular hole is slightly larger than the diameter of the fixed position.

5. The drilling tool according to claim 1, characterized in that: There are two symmetrical step holes at the two ends of the upper block; there are two threaded holes at the two ends of the lower block, which correspond to the step holes of the upper block respectively; bolts are inserted and tightened to complete the fixed connection.

6. The drilling tool according to claim 1, characterized in that: The upper end surface of the upper block is provided with a flat plate for calibration.

7. A method for drilling a stepped surface of a tubular workpiece, characterized in that: Step 1: Processing the outer circle, two end faces and inner hole of the tubular workpiece according to the raw material; Step 2: a circular groove is machined on the outer wall of the middle part of the tubular workpiece to divide the outer wall into a guide part for drilling guidance and a large diameter shaft on the side wall where an axial deep hole needs to be drilled; Step 3, drilling a plurality of guide through holes along the axial direction on the guide portion; Step 4, installing a plurality of drilling tools as described in any one of claims 1 to 6 on the annular groove; Step 5: The drill bit passes through the guide part and the guide holes on the drilling tool respectively, and processes a number of corresponding deep holes on the stepped surface between the outer circle segment and the annular groove; Step six, remove the guide part to complete the processing of the tubular workpiece.

8. The method according to claim 1, characterized in that: In step three, a calibration block is also arranged on the outer wall of the tubular workpiece as a calibration reference in the circumferential direction.

9. The method according to claim 7, characterized in that: The cross section of the correction block is rectangular, and a workpiece flat parallel to the upper surface of the correction block is machined on the guide portion and is used to calibrate with the flat of the upper block of the drilling fixture in step four.

10. The method according to claim 1, characterized in that: In step 5, after drilling a plurality of deep holes on one side of the stepped surface, the drilling tool is removed; then the tubular workpiece is turned around and the drilling on the other side is completed; A complete through-hole is formed.

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