Broaching method for variable-shape groove with depth-variable inner hole and machining tool
By combining a broaching tool for variable-depth grooves in the inner hole with a CNC wire drawing machine, the machining problem of long grooves with variable-depth inner holes in ultra-long steel pipes has been solved, achieving high-precision machining and reducing tool consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-04-10
AI Technical Summary
Existing technologies cannot effectively process the inner bore of steel pipes with ultra-long, gradually varying depths, and irregularly shaped long grooves, and non-metallic materials cannot be electrolytically processed.
The tool for grooving with variable inner hole depth is used, including components such as brush, plug, front guide sleeve, spring, broaching blade, rear guide sleeve, tool holder, and mandrel. The grooving process is achieved by driving a CNC wire drawing machine and a servo motor.
It improves the machining accuracy of long grooves with variable depths in the inner hole of ultra-long steel pipes, reduces tool consumption costs, and expands the range of groove machining.
Smart Images
Figure CN121820765A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of deep hole broaching, and particularly relates to a method for broaching a variable-depth and variable-shape groove in an inner hole and a machining tool. BACKGROUND
[0002] The present application belongs to the field of deep hole broaching, and particularly relates to a method for broaching a variable-depth and variable-shape groove in an inner hole and a machining tool. SUMMARY
[0003] (I) Technical problem to be solved The present application aims to solve the technical problem of providing a method for broaching a variable-depth and variable-shape groove in an inner hole and a machining tool to solve the problem that the prior art cannot broach a variable-depth and variable-shape long groove in an inner hole of an ultra-long steel pipe.
[0004] (II) Technical solution To solve the above technical problem, the present application provides a machining tool for broaching a variable-depth and variable-shape groove in an inner hole, comprising: a brush 1, a plug 2, a front guide sleeve 3, a spring 4, a compression screw 5, a broach blade 6, a body 7, a rear guide sleeve 8, a tool bar 9, and a mandrel 10. The mandrel 10 penetrates into the inside of the tool bar 9, the front end of the tool bar 9 is connected to the body 7, four rectangular knife mounting holes are formed in the body 7, the broach blade 6 is mounted in the rectangular knife mounting holes, and the broach blade 6 is freely movable up and down in the hole. The front end of the mandrel 10 extends into the body 7, two stepped circles are arranged on the mandrel 10 and matched with the inner hole of the body 7, so that the mandrel 10 runs smoothly without jamming when sliding left and right in the body 7. The front end of the body 7 is threadedly connected to the brush 1, and the connection is provided with the plug 2. The body 7 is sleeved with the front guide sleeve 3 and the rear guide sleeve 8, four rectangular knife mounting holes with the same size and position as the body 7 are formed in the front guide sleeve 3 and the rear guide sleeve 8, so that the broach blade 6 can smoothly slide through the rectangular knife mounting holes. Four springs are arranged in the body 7, the two ends of each spring are respectively pressed on the inclined surface of the mandrel 10 and the upper plane of the groove of the broach blade 6, the pre-tightening force of the spring is adjusted by a screw, and the blade is tightly attached to the inclined surface of the mandrel 10 and the upper plane of the groove of the broach blade 6 in the initial position. The body 7 is provided with a connecting head at the end, and the connecting head is connected to the tool bar 9 through a nut. The body 7 is provided with two oil injection holes in the circumferential direction, and the mandrel 10 is provided with two oil injection holes in the circumferential direction, which are used for spraying cutting oil from the inner hole of the mandrel 10 to flush away iron filings.
[0005] The rake angle of the broach blade 6 is 15-20°, the relief angle is 8-10°, the secondary offset angle is 1-2°, the width of the cutting edge is equal to the width of the groove, the chip breaking groove is provided with an R7.5mm, and the left and right included angles are 5°.
[0006] A variable-depth special-shaped groove broaching method, which is based on a machining tool and specifically comprises the following steps. Step 1: grinding and installing the broaching tool body; Step 2: installing the steel pipe on the numerical control broaching machine; Step 3: installing the broach blade; Step 4: installing the spring; Step 5: groove line broaching.
[0007] The step 1 specifically comprises the following steps. Step 11: grinding the outer diameters of the front guide sleeve 3 and the rear guide sleeve 8 according to the inner hole size of the machined part, so as to ensure that the gap between the guide sleeves and the inner hole is within 0.05mm.
[0008] Step 12: inserting the mandrel 10 into the tool bar 9 and connecting the body 7 with the tool bar 9.
[0009] The step 2 specifically comprises the following steps. Step 21: installing the steel pipe to be machined on the numerical control broaching machine; Step 22: inserting the body 7 into the steel pipe, adjusting the position of the steel pipe by adjusting the rollers on the broaching machine, so as to make the gap between the body 7 and the inner hole of the steel pipe within 0.05mm, and clamping the steel pipe.
[0010] The step 3 specifically comprises the following steps. Step 31: installing the broach blade 6 in the rectangular tool mounting hole of the body 7; Step 32: sliding the broach blade 6 up and down without jamming, rotating the tool bar of the machine tool by 90°, 180° and 270°, and repeating the above actions.
[0011] The step 4 specifically comprises the following steps. Step 41: installing the spring 4 in the square hole of the body 7, clamping one end of the spring 4 in the groove body of the broach blade, and placing the other end on the inclined conical surface of the mandrel, and then pressing the spring 4 with the pressing screw 5 so that the pressing screw 5 is in contact with the end surface of the spring 4; Step 42: sliding the broach blade 6 up and down without jamming, rotating the tool bar of the machine tool by 90°, 180° and 270°, and repeating the above actions.
[0012] The step 5 comprises: Step 51: according to the length, depth size of the groove, the prepared program is input into the device, the connected body 7 is inserted into the steel pipe together with the cutter bar 9 and the mandrel 10 driven by the spindle box 12, the spindle box 12 drives the cutter bar 9 and the mandrel 10 to move to the left end, at this time, the cutter bar and the mandrel are relatively static, and the broach blade 6 on the broaching cutter body is completely stretched out of the steel pipe to stop at the cutting predetermined position; Step 52: the servo motor 11 drives the mandrel 10 to move to the right end, the mandrel 10 cone surface lifts the blade, and the broaching movement is carried out, at the same time, the cutting oil enters the cutting area through the hole in the mandrel 10 to cool, and the brush 1 cleans the cut iron filings out of the steel pipe during the broaching; Step 53: after completing the broaching, the mandrel 10 is driven by the servo motor 11 to move to the left end, and the broach blade 6 is retracted by the cone surface and the spring 4 pressure, the spindle box 12 drives the cutter bar 9 and the broach 10 to move to the left end quickly, and returns to the cutting predetermined position; Step 54: repeat steps 52 and 53 until the groove broaching is stopped at the drawing size.
[0013] In the step 52, the cutter bar is touched during the broaching process, and the cutting state is observed; the vibration of the cutter bar is perceived, and if slight vibration occurs, the feed speed is appropriately increased; The cutting state is observed, and if burrs appear on both sides of the cutting, it means that the blade of the broach blade 6 has been worn, and then the blade of the broach blade 6 is ground and used after grinding.
[0014] After the machining is completed, the broaching cutter body is withdrawn, and then the steel pipe is removed, and the groove machining is completed.
[0015] (Three) beneficial effects Compared with the prior art, the present application has the following beneficial effects: a cutter body guide sleeve is matched with the hole to play a good guiding role; the vibration of the broach bar is perceived, and the cutting speed is appropriately increased if slight vibration occurs, which can be eliminated; whether burrs appear on both sides of the chip is determined to determine whether the broach blade has been worn out, and the vibration factor is excluded. The broach blade is connected with the mandrel taper surface by a spring, and any variable-depth groove machining can be completed; the broach blade can process any variable-depth groove by adopting reasonable materials and tool angles and chip breaking methods; the broach blade can ensure that the broach blade does not vibrate when the broach body moves back and forth, and the surface roughness of the groove is ensured; the two-side angle and the rake face of the broach blade can process inverted trapezoidal and other special-shaped grooves, expand the groove machining range, and the tool consumption cost is reduced. The present application significantly improves the machining precision of the variable-depth special-shaped long groove in the super-long steel pipe inner hole and reduces the tool consumption cost. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 It is a schematic diagram of the cutter structure of the present application. Figure 2 It is a specific structure diagram of the broach blade of the present application. DETAILED DESCRIPTION
[0017] In order to make the purpose, content and advantages of the present application more clear, the specific embodiments of the present application are described in further detail below in combination with the drawings and examples.
[0018] Example 1 The present embodiment provides an inner hole depth variable special-shaped groove broaching machining cutter, which comprises a brush 1, a plug 2, a front guide sleeve 3, a spring 4, a compression screw 5, a broach blade 6, a body 7, a rear guide sleeve 8, a cutter bar 9 and a mandrel 10. The mandrel 10 penetrates into the inside of the cutter bar 9, the front end of the cutter bar 9 is connected with the body 7, four rectangular cutter mounting holes are formed in the body 7, the broach blade 6 is mounted in the rectangular cutter mounting holes, and the broach blade 6 is freely movable up and down in the hole. The front end of the mandrel 10 extends into the body 7, two stepped circles that cooperate with the inner hole of the body 7 are arranged on the mandrel 10, so that the mandrel 10 runs smoothly without jamming when sliding left and right in the body 7. The front end of the body 7 is threadedly connected with the brush 1, and the connection is provided with the plug 2. The outer circle of the body 7 is sleeved with a front guide sleeve 3 and a rear guide sleeve 8, and four rectangular tool mounting holes with the same size and position as the body 7 are formed in the front guide sleeve 3 and the rear guide sleeve 8, so that the broach blade 6 can smoothly slide through the rectangular tool mounting hole; The body 7 is provided with four springs, and the two ends of each spring are respectively pressed on the inclined surface of the mandrel 10 and the upper flat surface of the groove of the broach blade 6, and the pre-tightening force of the spring is adjusted by a screw, so as to ensure that the blade is tightly attached to the inclined surface of the mandrel 10 and the upper flat surface of the groove of the broach blade 6 in the initial position. The body 7 is provided with a connecting head at the end, which is connected with the tool bar 9 through a nut. The body 7 is provided with two oil injection holes in the circumferential direction, and the mandrel 10 is provided with two oil injection holes in the circumferential direction, which are used for spraying cutting oil from the inner hole of the mandrel 10 to flush away iron filings.
[0019] The front angle of the broach blade 6 is 15°-20°, the rear angle is 8°-10°, the secondary offset angle is 1°-2°, the width of the blade edge is equal to the width of the groove, the chip breaking groove is set to R7.5mm, and the left and right included angle is set to 5°.
[0020] A variable-depth special-shaped groove broaching method, which is based on a machining tool and specifically includes the following steps: Step 1: grinding and installing the broaching tool body; Step 2: installing the steel pipe on the numerical control broaching machine; Step 3: installing the broach blade; Step 4: installing the spring; Step 5: groove line broaching.
[0021] The step 1 specifically includes: Step 11: grinding the outer diameter of the front guide sleeve 3 and the rear guide sleeve 8 according to the size of the inner hole of the machined part, so that the gap between the guide sleeve and the inner hole is within 0.05mm.
[0022] Step 12: inserting the mandrel 10 into the tool bar 9, and connecting the body 7 with the tool bar 9.
[0023] The step 2 specifically includes: Step 21: installing the steel pipe to be machined on the numerical control broaching machine; Step 22: inserting the body 7 into the steel pipe, adjusting the position of the steel pipe by adjusting the rollers on the broaching machine, so that the gap between the body 7 and the inner hole of the steel pipe is within 0.05mm, and clamping the steel pipe.
[0024] The step 3 specifically includes: Step 31: installing the broach blade 6 in the rectangular tool mounting hole of the body 7; Step 32: Push the broach blade 6 up and down without jamming, rotate the machine tool bar 90°, 180°, 270°, and repeat the above actions.
[0025] The step 4 specifically comprises: Step 41: Install the spring 4 in the square hole of the body 7, one end is clamped in the groove of the broach blade, and the other end is placed on the tapered surface of the mandrel, and the compression screw 5 is compressed to make it top on the end surface of the spring 4; Step 42: Push the broach blade 6 up and down without jamming, rotate the machine tool bar 90°, 180°, 270°, and repeat the above actions.
[0026] The step 5 comprises: Step 51: According to the length, depth and size of the groove, input the prepared program into the device, and connect the body 7 with the tool bar 9 and the mandrel 10, and drive them into the steel pipe under the driving of the spindle box 12, and drive the tool bar 9 and the mandrel 10 to move to the left end, at this time, the tool bar and the mandrel are relatively static, and when the broach blade 6 of the broaching tool body is completely stretched out of the steel pipe to the cutting predetermined position, stop; Step 52: The servo motor 11 drives the mandrel 10 to move to the right end, the tapered surface of the mandrel 10 lifts the blade, and the cutting oil enters the cutting area through the hole in the mandrel 10 to cool, and the brush 1 cleans the cut iron filings out of the steel pipe during the broaching; Step 53: After completing a broaching, the mandrel 10 is driven by the servo motor 11 to move to the left end, and the tapered surface is recovered and the spring 4 is pressed to retract the broach blade 6, and the spindle box 12 drives the tool bar 9 and the mandrel 10 to move to the left end quickly, and returns to the cutting predetermined position; Step 54: Repeat steps 52 and 53 until the groove is broached to the size of the drawing.
[0027] In the broaching process of step 52, the tool bar is touched by hand to observe the state of the cutting chips, and the vibration of the tool bar is perceived by hand, and if slight vibration occurs, the cutting speed is appropriately increased; The state of the cutting chips is observed, and if burrs appear on both sides of the cutting chips, it indicates that the blade of the broach blade 6 has been worn, and then the blade of the broach blade 6 is sharpened before use.
[0028] After the machining is completed, the broaching tool body is withdrawn, and then the steel pipe is removed, and the groove machining is completed.
[0029] Example 2 This example takes the broaching of a hole with a diameter D of φ100-φ200mm as an example to further illustrate the specific implementation of the present application.
[0030] Firstly, the inner hole of the steel pipe to be processed is measured, and the front and rear guide sleeves on the pull wire cutter body are ground according to the actual measured value, so as to ensure that the gap between the guide sleeves and the inner hole is within 0.05 mm. On the numerical control pull groove machine tool, the pull groove cutter body is installed at the threaded end of the machine tool cutter bar (9), and the mandrel (10) of the pull groove cutter body is connected with the machine tool. The steel pipe is installed on the equipment, then the pull groove cutter body is inserted into the steel pipe, the position of the steel pipe is adjusted by the rollers on the pull groove machine tool, it is ensured that the gap between the pull groove cutter body and the inner hole of the steel pipe is within 0.05 mm, and the steel pipe is clamped. The pull blade (6) is installed in the rectangular tool mounting hole of the pull groove cutter body, the pull blade (6) is pushed up and down by hand to slide without jamming, the machine tool cutter bar is rotated by 90°, 180° and 270°, and the above operation is repeated. According to the length, depth and size of the groove, the prepared program is input into the equipment, and the connected pull groove cutter body (cutter body assembly) is inserted into the steel pipe together with the cutter bar (9) and the mandrel (10) driven by the spindle box (12), the spindle box (12) drives the cutter bar (9) and the mandrel (10) to move to the left end together, at this time, the cutter bar and the mandrel are relatively stationary, when the pull blade on the pull groove cutter body is completely inserted into the steel pipe and reaches the cutting predetermined position, stop, the servo motor (11) drives the mandrel (10) to move to the right end, the mandrel (10) is used to lift the blade, and the pull groove movement is carried out according to the previously prepared program, while the cutting oil enters the cutting area through the inner hole of the mandrel (10) to cool, the brush (1) removes the iron filings cut off in the steel pipe during the pull cutting, after completing the pull cutting once, the mandrel (10) is moved to the left end under the drive of the servo motor (11), and the pull blade is retracted by using the tapered surface and the pressure of the spring (4), the spindle box (12) drives the cutter bar (9) and the pull rod (10) to move to the left end quickly, and returns to the cutting predetermined position, so as to repeat the above operation until the groove is pulled and cut to the size of the drawing, and then stop. During the pull cutting process, the cutter bar is touched by hand, and the state of the cutting chip is observed; the vibration of the cutter bar is perceived by the hand touching the cutter bar, if slight vibration occurs, the feed speed is appropriately increased, and the phenomenon can be eliminated; the state of the cutting chip is observed, if burrs appear on both sides of the cutting chip, it indicates that the cutting edge of the pull blade (6) has been worn, the machining is stopped, and the cutting edge of the pull blade (6) is ground before being used again. After the machining is completed, the pull groove cutter body is withdrawn, and then the steel pipe is removed, and the groove machining is completed.
[0031] The rake angle of the pull blade in the present application is 15°-20°, the relief angle is 8°-10°, the secondary offset angle is 1°-2°, the width of the cutting edge is equal to the width of the groove, the chip breaking groove is R7.5 mm, and the left and right included angle is 5°.
[0032] The above is only the preferred embodiment of the present application, and it should be pointed out that those skilled in the art can make some improvements and modifications without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.
Claims
1. A broaching tool for creating grooves with variable inner hole depth, characterized in that, include: Brush (1), plug (2), front guide sleeve (3), spring (4), clamping screw (5), pull blade (6), body (7), rear guide sleeve (8), tool bar (9), spindle (10); The spindle (10) is inserted into the inside of the tool holder (9). The front end of the tool holder (9) is connected to the body (7). The body (7) has four rectangular tool mounting holes. A puller blade (6) is installed in the rectangular tool mounting holes. The puller blade (6) is designed to move freely up and down in the hole. The front end of the mandrel (10) extends into the body (7). The mandrel (10) is provided with two stepped circles that fit into the inner hole of the body (7), so that the mandrel (10) can run smoothly without jamming when sliding left and right in the body (7). The front end of the main body (7) is threaded to a brush (1), and a plug (2) is provided at the connection point. The outer circle of the body (7) is fitted with a front guide sleeve (3) and a rear guide sleeve (8). The front guide sleeve (3) and the rear guide sleeve (8) are each provided with 4 rectangular tool holes of the same size and position as the body (7), so that the cutting blade (6) can slide smoothly through the rectangular tool holes. The body (7) is provided with 4 springs. Each spring presses its two ends on the inclined surface of the spindle (10) and the upper surface of the groove of the blade (6). The spring preload is adjusted by screws to ensure that the blade is in close contact with the inclined surface of the spindle (10) and the upper surface of the groove of the blade (6) in the initial position. The end of the body (7) is equipped with a connector, which is connected to the tool bar (9) by a nut; The body (7) has two oil spray holes in the circumferential chip groove, and the spindle (10) has two oil spray holes in the circumferential direction, so that cutting oil can be sprayed out from the inner hole of the spindle (10) to flush away the iron chips.
2. The broaching tool for variable-depth internal groove machining as described in claim 1, characterized in that, The cutting blade (6) has a front angle of 15° to 20°, a rear angle of 8° to 10°, a secondary deflection angle of 1° to 2°, a blade width equal to the groove width, a chip breaking groove set to R7.5mm, and a left and right included angle set to 5°.
3. A method for broaching deformable grooves with variable inner hole depth, characterized in that, The broaching method is implemented using the machining tool of claim 2, and specifically includes the following steps: Step 1: Grind and install the grooving tool body; Step 2: Install the steel pipe on the CNC wire drawing machine; Step 3: Install the blade; Step 4: Install the spring; Step 5: Groove line broaching.
4. The broaching method for variable-depth internal hole grooves as described in claim 3, characterized in that, Step 1 specifically includes: Step 11: Grind the outer diameter of the front guide sleeve (3) and the rear guide sleeve (8) according to the inner hole size of the part to be processed, and ensure that the gap between the guide sleeve and the inner hole is within 0.05mm. Step 12: Insert the mandrel (10) into the tool holder (9) and connect the body (7) to the tool holder (9).
5. The broaching method for variable-depth internal hole grooves as described in claim 4, characterized in that, Step 2 specifically includes: Step 21: Load the steel pipe to be processed onto the CNC wire drawing machine; Step 22: Insert the main body (7) into the steel pipe, adjust the position of the steel pipe by adjusting the rollers on the wire drawing machine, so that the gap between the main body (7) and the inner hole of the steel pipe is within 0.05mm, and clamp the steel pipe.
6. The broaching method for variable-depth internal hole grooves as described in claim 5, characterized in that, Step 3 specifically includes: Step 31: Insert the broaching blade (6) into the rectangular tool hole of the main body (7); Step 32: Push the broaching blade (6) up and down until it slides smoothly without jamming. Rotate the machine tool bar to rotate 90°, 180°, and 270°, and repeat the above actions.
7. The broaching method for variable-depth internal grooves as described in claim 6, characterized in that, Step 4 specifically includes: Step 41: Insert the spring (4) into the square hole of the body (7), with one end locked in the groove of the cutting blade and the other end placed on the inclined conical surface of the mandrel. Tighten it with the clamping screw (5) so that it presses against the end face of the spring (4). Step 42: Push the cutting blade (6) up and down without any movement, rotate the machine tool bar 90°, 180°, 270°, and repeat the above actions.
8. The broaching method for variable-depth internal hole grooves as described in claim 7, characterized in that, Step 5 includes: Step 51: According to the length and depth of the groove, input the prepared program into the device, and insert the connected body (7) along with the tool bar (9) and the mandrel (10) into the steel pipe under the drive of the spindle box (12). The spindle box (12) drives the tool bar (9) and the mandrel (10) to move to the left. At this time, the tool bar and the mandrel are relatively stationary. Stop when the grooving cutter body pulls the blade (6) completely extends out of the steel pipe and reaches the predetermined cutting position. Step 52: The servo motor (11) drives the spindle (10) to move to the right end, and the spindle (10) cone surface lifts the blade to perform the grooving motion. At the same time, the cutting oil enters the cutting area along the inner hole of the spindle (10) to cool it. The brush (1) cleans the cut iron chips out of the steel pipe during the broaching process. Step 53: After one broaching operation is completed, the spindle (10) moves to the left under the drive of the servo motor (11), and the broaching tool (6) is retracted by the conical surface retraction and the pressure of the spring (4). The spindle box (12) drives the tool holder (9) and the pull rod (10) to move quickly to the left and return to the predetermined cutting position. Step 54: Repeat steps 52 and 53 until the groove is broached to the dimensions shown in the drawing.
9. The broaching method for variable-depth internal hole grooves as described in claim 8, characterized in that, In step 52, during the broaching process, touch the tool holder by hand to observe the chip condition; touch the tool holder by hand to sense its vibration, and if slight vibration occurs, appropriately increase the feed rate. Observe the state of the chips. If burrs appear on both sides of the chips, it means that the cutting edge of the broach (6) is worn. Then stop processing and sharpen the cutting edge of the broach (6) before using it again.
10. The broaching method for variable-depth internal hole grooves as described in claim 9, characterized in that, After processing is completed, the grooving tool is removed, measurements are taken, and then the steel pipe is removed, completing the grooving process.