A tapping machine for metal piece machining

Abstract

This invention discloses a tapping machine for metal parts processing, relating to the field of thread processing technology. It includes a positioning slide, on which is provided an input spindle and a rotatable, axially movable tap-bearing mandrel, connected by a torque-limiting transmission. A tap is clamped on the tap-bearing mandrel. A lead reference feed sleeve slides on the positioning slide, driven by the input spindle to move according to the tap's lead. The lead reference feed sleeve is provided with a double load transfer sleeve and a detachable verification slide. The verification slide moves with the lead reference feed sleeve. When the axial displacement difference between the tap-bearing mandrel and the lead reference feed sleeve exceeds a preset range, the verification slide stops moving. After the verification slide completes a preset continuous stroke, it triggers the double load transfer sleeve, activating the cutting torque transmission and axial feed. This invention limits the activation timing of the cutting load through continuous thread verification, reducing the risk of thread damage when the tap re-enters an existing thread.

Description

Technical Field

[0001] This invention relates to the field of metal thread processing technology, and in particular to a tapping machine for metal part processing. Background Technology

[0002] A tapping machine uses a tap to machine internal threads in a pre-drilled hole in a metal part. In segmented tapping with complete tap retraction and chip removal, the tap completes one segment of machining, then exits the hole to remove chips, before re-entering the existing threaded segment to continue machining. When the tap re-enters, its teeth need to engage along the helix of the existing internal thread to connect the threads formed by the two segments.

[0003] For tapping methods that use spindle rotation combined with axial forced feed, when the tap reappears near the hole after it has completely withdrawn, there may be misalignment between the teeth and the existing thread. If the torque and axial feed required for continued cutting are applied directly at this time, the tap is likely to squeeze the original tooth side at the hole opening, causing damage to the entry thread. If forced entry is continued in the misaligned state, it may also form staggered tooth marks, increasing the load on subsequent machining.

[0004] Reducing the driving force during the initial re-entry phase can lessen the contact load between the tap and the borehole, but a short entry distance is insufficient to determine whether the tap can continue to advance along the existing thread. If the cutting load is restored too early afterward, the misalignment from the re-entry will still be carried over into the subsequent cutting process. Summary of the Invention

[0005] One object of the present invention is to provide a tapping machine for machining metal parts, so as to reduce the risk of thread damage caused by premature application of cutting torque and axial feed when the tap is completely withdrawn and re-enters the existing thread.

[0006] A tapping machine for machining metal parts according to an embodiment of the present invention includes a positioning slide. The positioning slide is provided with an input spindle and a rotatable, axially movable tap-bearing mandrel, and the two are connected by a torque-limiting transmission. A tap is clamped on the tap-bearing mandrel. A lead reference feed sleeve is slidably provided on the positioning slide. Each rotation of the input spindle drives the lead reference feed sleeve to move the tap axially by one lead.

[0007] The lead reference feed sleeve is equipped with a double load transfer sleeve and a detachable verification slide. The verification slide moves with the lead reference feed sleeve. When the axial displacement difference between the tap bearing mandrel and the lead reference feed sleeve exceeds a preset range, the verification slide stops moving.

[0008] When the verification slide completes a preset continuous stroke, it triggers the dual load transfer sleeve, causing the input main axis to transmit cutting torque to the tap-bearing mandrel. Upon triggering, the dual load transfer sleeve causes the lead reference feed sleeve to drive the tap-bearing mandrel axially forward.

[0009] The axial displacement difference is based on the position of the verification slide when it begins continuous follow-up during the same re-entry, comparing the actual axial displacement of the tap-bearing mandrel with the reference axial displacement of the lead reference feed sleeve thereafter. The preset continuous stroke is the continuous axial stroke required for the verification slide to move from the position where it begins continuous follow-up to the trigger position.

[0010] Preferably, an axially offset sleeve is rotatably fitted onto the tap-bearing mandrel, and the two are axially limited in fit. A contact spring and a pull-back check spring are provided between the positioning slide and the axially offset sleeve. The contact spring applies an inward thrust to the axially offset sleeve during the initial insertion phase, and stops transmitting force to the axially offset sleeve after the initial insertion phase ends. The pull-back check spring continues to apply a check force outward to the axially offset sleeve.

[0011] Preferably, a floating contact seat is provided between the contact spring and the axial offset sleeve, and a contact limiting shoulder is fixed on the positioning slide. The floating contact seat is pushed by the contact spring and stops after moving to the contact limiting shoulder; the axial offset sleeve continues to move into the hole and separates from the floating contact seat.

[0012] Preferably, a verification return spring is provided between the verification slide and the positioning slide. When the axial displacement difference exceeds the preset range, the verification slide disengages from the lead reference feed sleeve, and the verification return spring returns the verification slide to its initial position. During the preset continuous stroke, the stroke after the contact spring stops transmitting force to the axial offset sleeve is not less than one lead of the tap.

[0013] Preferably, a single-proof latch is slidably mounted on the verification slide, and a single engaging portion is provided on the lead reference feed sleeve to engage with the single-proof latch. An actual travel follower pin is provided on the axial offset sleeve, and a difference tolerance groove is formed on the single-proof latch. A roller is provided at the end of the actual travel follower pin to contact the difference tolerance groove. The two sides of the difference tolerance groove are inclined surfaces. When the axial displacement difference exceeds the preset range, the roller moves along the corresponding groove wall, pushing the single-proof latch away from the engaging portion.

[0014] Preferably, the axial offset sleeve is further provided with a return-reset surface, and a reset lifting rod is slidably provided on the positioning slide. When the axial offset sleeve returns to the floating contact seat, the return-reset surface pushes the reset lifting rod, lifting the single-use certification latch away from the locking part.

[0015] Preferably, a torque-limiting tooth-following clutch and a two-way cutting clutch are provided between the input spindle and the tap-bearing mandrel, with the torque-limiting tooth-following clutch forming the torque-limiting transmission connection. An axial clamping member is provided between the tap-bearing mandrel and the lead reference feed sleeve. The dual load transfer sleeve is respectively driven by the two-way cutting clutch and the axial clamping member, and their shared axial stroke engages them.

[0016] Preferably, a bistable retainer is provided between the lead reference feed sleeve and the dual load transfer sleeve, and the trigger end of the bistable retainer is driven and engaged with the verification slide. After being triggered, the bistable retainer maintains the engagement position of the dual load transfer sleeve, and maintains the engagement of the bidirectional cutting clutch and the axial clamping member when the input spindle reverses.

[0017] Preferably, the positioning slide is provided with a non-rotating orifice reference sleeve for determining the position of the workpiece orifice. An exit release ring is slidably mounted on the non-rotating orifice reference sleeve, and the exit release ring is in transmission engagement with the bistable retainer. A failure release spring is provided between the lead reference feed sleeve and the dual load transfer sleeve. After the last engaging tooth of the tap exits the orifice, the tap-bearing mandrel drives the exit release ring to release the bistable retainer, and the failure release spring causes the dual load transfer sleeve to retract to the position where the bidirectional cutting clutch and the axial clamping member are disengaged.

[0018] The beneficial effects of this invention are as follows: By verifying the detachable fit between the slide and the lead reference feed sleeve, this invention transforms the comparison result between the actual axial displacement of the tap and the lead reference displacement into the verification of the slide's follow-up state. Utilizing the triggering of the double load transmission sleeve with a preset continuous stroke limit, the connection of cutting torque and axial feed is based on the premise that the tap completes continuous follow-up verification under torque-limited rotation. This reduces the likelihood of the tap forcibly entering an existing thread in a misaligned state due to premature application of cutting load, lowers the risk of thread stripping and interlacing marks at the hole opening, and helps maintain the connection between threads before and after segmented tapping. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the tapping part of the present invention;

[0022] Figure 3 This is a cross-sectional view of the mating part between the axial offset sleeve and the tap bearing mandrel of the present invention;

[0023] Figure 4 for Figure 3 A magnified view of a section at point A in the middle;

[0024] Figure 5 This is a cross-sectional view of the slide block and its disengagement and repositioning structure for verifying the present invention.

[0025] Figure 6 for Figure 5 A magnified view of a section at point B in the middle;

[0026] Figure 7 This is a schematic diagram showing the fit between the dual load transfer sleeve and the two joint structures of the present invention;

[0027] Figure 8 This is a schematic diagram illustrating the state of engagement of the slide-triggered dual load transfer sleeves in this invention.

[0028] Figure 9 This is a schematic diagram showing the state in which the two joining structures remain joined during the reverse retraction process of the present invention;

[0029] Figure 10 This is a schematic diagram showing the state of the dual load transfer sleeve returning to the release position according to the present invention;

[0030] Figure 11 This is a schematic diagram showing the state of the tap before and after exiting the orifice and its engagement with the exit release ring.

[0031] In the diagram: 1. Base; 11. Linear guide rail; 12. Workpiece fixture; 2. Positioning slide; 21. Input spindle; 22. Spindle motor; 23. Lead reference screw; 24. Fitting limit shoulder; 25. Fixed guide seat; 26. Spring fixing seat; 27. Reset lifting rod; 28. Proof stroke shoulder; 3. Tap bearing mandrel; 31. Actual stroke shoulder; 32. Tap chuck; 321. Tap; 33. Torque limiting tooth-following clutch; 34. Two-way cutting clutch; 4. Axial offset sleeve; 41. Fitting spring; 42. Pull-back calibration spring; 43. Floating contact seat; 44. Bidirectional rotary isolation bearing assembly; 45. Return and reset surface; 46. Actual stroke follower pin; 5. Lead reference feed sleeve; 51. Replaceable lead nut; 52. Axial clamping element; 521. Rotary isolation thrust bearing; 6. Verification slide; 61. Single verification latch; 611. Differential tolerance groove; 62. Verification reset spring; 7. Dual load transfer sleeve; 71. Dual stability retainer; 72. Failure release spring; 8. Non-rotating orifice reference sleeve; 81. Outlet release ring; 82. Orifice contact foot; 9. Workpiece. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0033] like Figure 1 , Figure 2 As shown, this embodiment provides a tapping machine for metal parts processing, including a base 1 and a positioning slide 2. A linear guide rail 11 is provided on the base 1, and the positioning slide 2 is slidably mounted on the linear guide rail 11, allowing its position to be adjusted along the tapping direction. The positioning slide 2 is equipped with a spindle motor 22, an input spindle 21, and a tap-bearing mandrel 3, with the spindle motor 22 being drive-connected to the input spindle 21. The tap-bearing mandrel 3 is coaxially mounted with the input spindle 21, and a tap chuck 32 is provided at the front end of the tap-bearing mandrel 3, with a tap 321 clamped inside the tap chuck 32. The tapping machine also includes a workpiece clamp 12 for holding the workpiece 9.

[0034] In this embodiment, the example is taken where tap 321 completely exits the hole and then re-enters the existing threaded section to continue tapping. Workpiece 9 remains clamped during re-entry and continued cutting, and the specifications of tap 321 match the existing internal thread. The direction in which tap 321 enters the hole of workpiece 9 is referred to as the inward direction, and the opposite direction is referred to as the outward direction.

[0035] The positioning slide 2 is equipped with a non-rotating orifice reference sleeve 8, and an orifice contact foot 82 is provided at the end of the non-rotating orifice reference sleeve 8 facing the workpiece 9. The orifice contact foot 82 abuts against the surface around the orifice of the workpiece 9 to determine the orifice position. With the tap 321 aligned with the hole axis of the workpiece 9, the positioning slide 2 is adjusted to the re-entry position along the tapping direction and then held in position. The axial movement during the re-entry stage is accomplished by the movement of the tap-bearing mandrel 3 relative to the positioning slide 2.

[0036] The tap-bearing mandrel 3 is supported on the positioning slide 2 and can rotate around its own axis and move along its own axis. For example... Figure 7 As shown, a torque-limiting tooth-following clutch 33 and a two-way cutting clutch 34 are provided between the input spindle 21 and the tap-bearing mandrel 3. The input side of the torque-limiting tooth-following clutch 33 is connected to the input spindle 21, and the output side is in transmission engagement with the tap-bearing mandrel 3. This transmission engagement preserves the axial movement stroke of the tap-bearing mandrel 3.

[0037] At the start of the reentry verification, the bidirectional cutting clutch 34 is disengaged, and the input spindle 21 drives the tap-bearing mandrel 3 to rotate via the torque-limiting clutch 33. The torque transmitted by the torque-limiting clutch 33 is used to maintain the tap 321 rotating along the existing thread; when the rotational resistance torque of the tap 321 exceeds the torque-limiting value, the torque-limiting clutch 33 slips relative to the tap-bearing mandrel 3, limiting the torque transmitted to the tap-bearing mandrel 3.

[0038] like Figure 2 As shown, a lead reference screw 23 is rotatably mounted on the positioning slide 2, and the lead reference screw 23 is connected to the input spindle 21 for transmission. A lead reference feed sleeve 5 is also slidably mounted on the positioning slide 2. The lead reference feed sleeve 5 is guided and constrained, keeping it circumferentially stationary but able to move axially along the tap-bearing mandrel 3. A replaceable lead nut 51 is fixed on the lead reference feed sleeve 5, and the replaceable lead nut 51 is threadedly engaged with the lead reference screw 23.

[0039] Specifically, the transmission relationship between the lead reference screw 23 and the input spindle 21, and the matching lead of the lead reference screw 23 and the replaceable lead nut 51, ensure that for each revolution of the input spindle 21, the lead reference feed sleeve 5 moves the tap 321 axially by one lead. In this embodiment, a single-start internal thread is machined, and this lead is equal to the pitch. When the input spindle 21 reverses direction, the lead reference feed sleeve 5 retracts in the direction outward from the hole.

[0040] like Figure 3 , Figure 4 As shown, the tap-bearing mandrel 3 has an actual stroke shoulder 31, and an axial offset sleeve 4 is fitted over the actual stroke shoulder 31. The axial offset sleeve 4 is in sliding engagement with the positioning slide 2, and its circumferential rotation is constrained. A bidirectional rotary isolation bearing assembly 44 is provided inside the axial offset sleeve 4. The bidirectional rotary isolation bearing assembly 44 is located on both sides of the actual stroke shoulder 31 along the axial direction, so that the axial offset sleeve 4 and the tap-bearing mandrel 3 form an axial limiting engagement.

[0041] The axial offset sleeve 4 moves axially with the tap bearing mandrel 3, and the tap bearing mandrel 3 can rotate relative to the axial offset sleeve 4. The axial force acting on the axial offset sleeve 4 is transmitted to the actual stroke shoulder 31 through the bidirectional rotary isolation bearing assembly 44, thereby transmitting axial forces towards the inside and outside of the hole to the tap bearing mandrel 3 while the axial offset sleeve 4 remains circumferentially stationary.

[0042] The positioning slide 2 is equipped with spring support seats located on both sides of the axial offset sleeve 4. A contact spring 41 and a pull-back check spring 42 are respectively provided between the spring support seats and the axial offset sleeve 4. A floating contact seat 43 is provided between the contact spring 41 and the axial offset sleeve 4, and the floating contact seat 43 is slidably disposed along the tapping direction. A contact limiting shoulder 24 is fixed on the positioning slide 2, and the contact limiting shoulder 24 is located on the path of the floating contact seat 43 moving into the hole.

[0043] In the initial stage of the entry hole, the contact spring 41 pushes against the floating contact seat 43, which abuts against the axial offset sleeve 4, transmitting the inward thrust to the tap-bearing mandrel 3. The pullback check spring 42 applies an outward force to the axial offset sleeve 4. The initial preload ensures that the thrust transmitted by the contact spring 41 through the floating contact seat 43 is greater than the reverse force and movement resistance of the pullback check spring 42, causing the tap 321 to make light-load contact with the existing threaded inlet.

[0044] After tap 321 is screwed into the existing thread, it drives tap-bearing mandrel 3 and axial offset sleeve 4 to move into the hole. Floating contact seat 43 moves along with the contact spring 41 until it abuts against contact limiting shoulder 24. At this point, floating contact seat 43 is limited, and axial offset sleeve 4 continues to move into the hole and separates from floating contact seat 43.

[0045] It should be noted that after the floating contact seat 43 is limited, the contact spring 41 still acts on the floating contact seat 43, and its force is received by the contact limiting shoulder 24 and is no longer transmitted to the axial offset sleeve 4. The pull-back check spring 42 continues to apply a check force towards the outside of the hole to the axial offset sleeve 4, and the tap 321 needs to overcome this check force when it continues to advance along the existing thread.

[0046] like Figure 5 , Figure 6 As shown, a fixed guide seat 25 and a spring fixing seat 26 are fixed on the positioning slide 2, and the verification slide 6 slides axially along the fixed guide seat 25. A verification reset spring 62 is provided between the verification slide 6 and the spring fixing seat 26, and an initial limiting part is provided on the fixed guide seat 25 to cooperate with the verification slide 6. The verification reset spring 62 applies a reset force to the verification slide 6 toward the initial limiting part.

[0047] A single-test latch 61 is slidably mounted on the verification slide 6 in a direction intersecting the spindle axis. A latch return spring is provided between the single-test latch 61 and the verification slide 6. A single locking part is provided on the lead reference feed sleeve 5. The latch return spring applies a force toward the locking part to the single-test latch 61. After the single-test latch 61 is engaged with the locking part, the lead reference feed sleeve 5 moves the verification slide 6 through the contact between the locking part and the single-test latch 61.

[0048] An actual travel follower pin 46 is fixed on the axial offset sleeve 4, and a roller is provided at the end of the actual travel follower pin 46. A differential tolerance groove 611 is provided on the single-use certification latch 61, and the roller is located in the differential tolerance groove 611. The two sides of the differential tolerance groove 611 are inclined surfaces with opposite directions, corresponding to two deviations: the actual axial displacement is greater than or less than the reference axial displacement.

[0049] The axially offset sleeve 4 is provided with a return-reset surface 45, and a reset lifting rod 27 is slidably provided on the positioning slide 2. The pushed part of the reset lifting rod 27 is opposite to the return-reset surface 45, and the lifting part extends to below the single-use certification latch 61. In the initial section of the inlet, the axially offset sleeve 4 abuts against the floating contact seat 43, and the return-reset surface 45 holds the reset lifting rod 27 in the raised position, so that the single-use certification latch 61 is disengaged from the locking part.

[0050] After the axial offset sleeve 4 separates from the floating contact seat 43, the return reset surface 45 moves away, and the reset lifting rod 27 releases the lifting of the single-test latch 61. When the locking part moves with the lead reference feed sleeve 5 to below the single-test latch 61, the single-test latch 61 is locked into the locking part under the action of the latch return spring, and the verification slide 6 begins to move with the lead reference feed sleeve 5. The state after the single-test latch 61 completes locking is taken as the starting state of this continuous verification. The travel of the inlet hole before locking and the transition travel of the latch into the locking part are not included in the preset continuous travel.

[0051] The axial displacement difference is based on the initial state of this continuous verification, comparing the subsequent axial displacements of the tap-bearing mandrel 3 and the lead reference feed sleeve 5. The difference tolerance groove 611 moves with the verification slide 6, and the roller moves with the moving pin 46 and the axial offset sleeve 4 along with the tap-bearing mandrel 3 through the actual stroke. The change in the relative position of the roller and the difference tolerance groove 611 reflects the axial displacement difference between the two.

[0052] The contour of the differential tolerance groove 611, the roller size, and the engagement depth of the single-certification latch 61 with the latching part jointly determine the preset range. When the axial displacement difference is within the preset range, the relative movement of the roller is insufficient to disengage the single-certification latch 61 from the latching part; when the axial displacement difference exceeds the preset range, the roller moves along the corresponding inclined surface, overcoming the force of the latch return spring, and lifts the single-certification latch 61 away from the latching part.

[0053] After the single-test latch 61 disengages, the test slide 6 stops following the lead reference feed sleeve 5 and returns to the initial limit position under the action of the test reset spring 62. When the lead reference feed sleeve 5 continues to advance, the individual locking part leaves the initial locking position, and the intermittent movement strokes are not accumulated into one continuous test stroke. When the axial offset sleeve 4 retracts out of the hole after separation and contacts the floating contact seat 43 again, it pushes the reset lifting rod 27 by touching the reset surface 45, lifting the single-test latch 61 away from the locking part, and the test slide 6 also returns to the initial limit position.

[0054] like Figure 5 , Figure 7 , Figure 8As shown, a double load transfer sleeve 7 is axially slidable on the lead reference feed sleeve 5, with a bistable retainer 71 and a failure release spring 72 between them. The failure release spring 72 applies a force toward the release position to the double load transfer sleeve 7. A verification stroke shoulder 28 is fixed on the positioning slide 2, and a trigger rod is slidably mounted on the verification slide 6. A trigger return spring is provided between the trigger rod and the verification slide 6. The verification stroke shoulder 28 forms a push surface on the side facing the trigger rod. When the verification slide 6 moves, the follower part of the trigger rod contacts the push surface and moves relative to the verification slide 6 due to the push surface.

[0055] The bistable retainer 71 includes two retaining rods hinged together. The outer ends of the two retaining rods are respectively hinged to the lead reference feed sleeve 5 and the dual load transfer sleeve 7, with an elbow formed at the middle hinge. An engagement rocker arm is hinged to the lead reference feed sleeve 5, and a retaining stop that cooperates with the retaining rods is fixed thereon. The trigger rod engages with one end of the engagement rocker arm in a one-way push-fit, and the other end of the engagement rocker arm pushes against the elbow, causing the two retaining rods to unfold and move the dual load transfer sleeve 7 toward the engagement position.

[0056] Furthermore, the preset continuous stroke begins from the position where the single verification latch 61 completes engagement and the verification slide 6 begins continuous follow-up, and ends at the position where the trigger rod causes the bistable retainer 71 to enter the engagement holding state. The positions of the engaging part and the verification stroke shoulder 28 are coordinated so that the engagement start point is located after the floating contact seat 43 separates from the axial offset sleeve 4, and the continuous stroke from the engagement start point to the trigger end point is not less than one lead of the tap 321. The arrangement of the engagement position takes into account the axial displacement deviation within the preset range, but the contact stage and the engagement transition stage are not included in this continuous stroke.

[0057] The bidirectional cutting clutch 34 is equipped with friction elements that are respectively connected to the input spindle 21 and the tap-bearing spindle 3. The dual load transmission sleeve 7 is in transmission engagement with the pressing part of the bidirectional cutting clutch 34. When the dual load transmission sleeve 7 moves toward the engagement position, the opposing friction elements are pressed together, thereby transmitting the torque required for forward continuous cutting and reverse retraction of the bidirectional cutting clutch 34.

[0058] like Figure 7 , Figure 8 As shown, the rotary isolation thrust bearing 521 is axially limited and mounted on the tap-bearing mandrel 3. It has an inner bearing portion that rotates with the tap-bearing mandrel 3 and a non-rotating bearing portion located on its periphery. The two bearing portions cooperate with thrust support members placed on both sides of the axial direction to transmit axial forces towards the inside and outside of the hole. The non-rotating bearing portion slides with the axial guide member on the positioning slide 2, and can remain circumferentially fixed as the tap-bearing mandrel 3 moves axially. Its outer side is provided with a part for clamping by the axial clamping member 52.

[0059] The axial clamping member 52 includes clamping blocks arranged opposite each other. A clamping guide portion is provided on the lead reference feed sleeve 5. The clamping blocks move closer to or further away from the non-rotating load-bearing portion along the clamping guide portion. A release spring is provided between the clamping blocks and the clamping guide portion, and a rolling follower is provided on the force-bearing side of the clamping blocks. A wedge surface is provided on the double load transfer sleeve 7, which contacts the rolling follower. When the double load transfer sleeve 7 moves towards the engagement position, the wedge surface pushes the clamping blocks to move towards each other through the rolling follower, clamping the non-rotating load-bearing portion.

[0060] After clamping, the axial feed force of the lead reference feed sleeve 5 is transmitted to the tap bearing mandrel 3 via the clamping block, the non-rotating load-bearing part, and the thrust support. The tap bearing mandrel 3 rotates relative to the clamping block via the rotating isolation thrust bearing 521. The dual load transfer sleeve 7 engages the bidirectional cutting clutch 34 during the same axial stroke and pushes the clamping block to hold the non-rotating load-bearing part. When the dual load transfer sleeve 7 reaches the engagement position, both parts are in the engaged state.

[0061] like Figure 7 , Figure 9 As shown, after the elbow of the bistable retainer 71 crosses the line connecting the two outer hinge points, the retaining link abuts against the retaining stop. Under the action of the failure release spring 72 and the engagement reaction force, the retaining link remains abutted, keeping the dual load transfer sleeve 7 in the engaged position. When the trigger rod returns, it disengages from the engagement rocker arm and does not pull the retaining link back. This holding state continues during the stop and reverse rotation of the input spindle 21. When the input spindle 21 reverses, the bidirectional cutting clutch 34 transmits the reverse retraction torque, and the lead reference feed sleeve 5 drives the tap-bearing mandrel 3 to retract out of the hole through the axial clamping member 52.

[0062] like Figure 2 , Figure 10 , Figure 11 As shown, a hole release ring 81 is slidably mounted on the non-rotating orifice reference sleeve 8 along the axial direction, and the hole release ring 81 is connected to a transmission rod. A release rocker arm is hinged to the bracket on the positioning slide 2. One end of the release rocker arm abuts against the transmission rod, and the other end acts on the elbow of the bistable retainer 71. A reset spring is provided between the hole release ring 81 and the non-rotating orifice reference sleeve 8 to return the hole release ring 81 to the triggering position.

[0063] The release ring 81 is positioned to push against the tap chuck 32 when it retracts, and the tap chuck 32 moves axially with the tap-bearing spindle 3. The axial contact position between the release ring 81 and the tap chuck 32 is set according to the clamping extension length of the tap 321 and the hole position determined by the hole contact foot 82, so that after the last tooth of the tap 321 that engages with the internal thread passes the hole opening, the tap chuck 32 pushes out the release ring 81.

[0064] After the outlet release ring 81 is pushed, it pushes the release rocker arm via the transmission rod. The release rocker arm causes the elbow to move back to the line connecting the two outer hinge points, releasing the holding link from the double load transmission sleeve 7. The failure release spring 72 pushes the double load transmission sleeve 7 back to the release position, the bidirectional cutting clutch 34 is released, the wedge surface exits the clamping position, and the clamping block releases the non-rotating bearing part under the action of the opening spring. After the tap chuck 32 moves back into the hole and away from the outlet release ring 81, the outlet release ring 81 returns to the ready-to-trigger position under the action of its return spring.

[0065] It should be noted that during tool retraction, the axial offset sleeve 4 may first collide with the floating contact seat 43, causing the verification slide 6 to reset. At this time, the dual load transfer sleeve 7 is still held in the engaged position by the dual stabilizing retainer 71, and the reset of the verification slide 6 does not disengage the bidirectional cutting clutch 34 from the axial clamping member 52.

[0066] Before use in this embodiment, the lead reference screw 23 and replaceable lead nut 51 are configured according to the lead of tap 321 to determine the separation position of the contact limiting shoulder 24, the engagement position of the single-test latch 61, and the trigger position of the test stroke shoulder 28. The existing complete internal thread length of the workpiece 9 hole should cover the initial section of the hole, the engagement transition stage, and the subsequent continuous test stroke, so that the continuous test is completed within the existing thread section.

[0067] The forces of the engagement spring 41 and the pullback check spring 42 are matched with the torque limiting value of the torque following clutch 33. This ensures that when the tap 321 is normally screwed into the existing thread, it can overcome the force of the pullback check spring 42 and the moving resistance. When re-entry is obstructed, the torque transmission is limited by the torque limiting clutch 33. The spring force and torque limiting value are selected based on the material of the workpiece 9, the tap 321, and the lubrication conditions.

[0068] Working principle: The workpiece 9 is clamped, and the positioning slide 2 is adjusted to the re-entry position. The bidirectional cutting clutch 34 remains disengaged from the axial clamping member 52. The spindle motor 22 drives the input spindle 21 to rotate forward. The torque limiting clutch 33 drives the tap 321 to rotate, and the contact spring 41 makes the tap 321 lightly contact the existing thread. After the initial section of the hole is completed, the axial offset sleeve 4 separates from the floating contact seat 43, the contact thrust stops being transmitted, the reset lifting rod 27 releases the lifting, and the single-pass verification shows that the latch 61 engages with the corresponding locking part under the action of the latch return spring, verifying that the slide 6 begins to move continuously.

[0069] When the axial displacement difference exceeds the limit during continuous verification, the roller lifts the single-test latch 61 away from the locking part via the difference tolerance groove 611; when the axial offset sleeve 4 retraces, the reset lifting rod 27 lifts the single-test latch 61 away from the locking part. The verification slide 6 returns to the initial limit part under the action of the verification reset spring 62, the bidirectional cutting clutch 34 and the axial clamping member 52 remain disengaged, and after the input spindle 21 reverses, the tap 321 is driven back by the torque limiting follow-tooth clutch 33.

[0070] When the verification slide 6 moves continuously to the trigger endpoint, the trigger rod pushes the elbow of the holding link through the engagement rocker arm to cross the line connecting the two outer end hinge points, and the double load transmission sleeve 7 enters the engagement position. The bidirectional cutting clutch 34 transmits cutting torque to the tap-bearing mandrel 3, and the axial clamping member 52 clamps the non-rotating bearing part, so that the tap-bearing mandrel 3 follows the lead reference feed sleeve 5 axially, and the tap 321 continues cutting along the existing thread to the end point of the previous tapping section.

[0071] After the continuous cutting is completed, the input spindle 21 reverses, the bistable retainer 71 maintains engagement, and the tap 321 retracts along the internal thread of the hole. After the last meshing tooth of the tap 321 exits the hole, the tap chuck 32 pushes out the hole release ring 81, and is released from holding via the transfer rod and release rocker arm. The double load transfer sleeve 7 retracts under the action of the failure release spring 72, and the cutting drive and axial clamping are released. The lead reference feed sleeve 5 and the tap bearing mandrel 3 return to the re-entry position, and the verification slide 6 is held in the initial position by the verification return spring 62. The next re-entry is performed again according to the above separation, engagement, and continuous verification process.

[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A tapping machine for machining metal parts, comprising a positioning slide (2), characterized in that: The positioning slide (2) is provided with an input spindle (21) and a tap bearing mandrel (3) that can rotate and move axially, and the two are connected by a torque limiting transmission. A tap (321) is clamped on the tap bearing mandrel (3). The positioning slide (2) is provided with a lead reference feed sleeve (5). Each time the input spindle (21) rotates, it drives the lead reference feed sleeve (5) to move the tap (321) by one lead along the axial direction. The lead reference feed sleeve (5) is provided with a double load transfer sleeve (7) and a detachable verification slide (6). The verification slide (6) moves with the lead reference feed sleeve (5). When the axial displacement difference between the tap bearing mandrel (3) and the lead reference feed sleeve (5) exceeds the preset range, the verification slide (6) stops moving. When the verification slide (6) completes the preset continuous stroke, it triggers the double load transmission sleeve (7) so that the input spindle (21) transmits cutting torque to the tap bearing mandrel (3); after the double load transmission sleeve (7) is triggered, the lead reference feed sleeve (5) drives the tap bearing mandrel (3) to feed axially.

2. The tapping machine for metal parts processing according to claim 1, characterized in that, An axial offset sleeve (4) is rotatably fitted on the tap bearing mandrel (3), and the two are axially limited and matched; a fitting spring (41) and a pull-back check spring (42) are provided between the positioning slide (2) and the axial offset sleeve (4); the fitting spring (41) applies a thrust towards the axial offset sleeve (4) in the initial stage of the hole, and stops transmitting force to the axial offset sleeve (4) after the initial stage of the hole is completed, while the pull-back check spring (42) continues to apply a check force towards the axial offset sleeve (4) towards the outside of the hole.

3. The tapping machine for metal parts processing according to claim 2, characterized in that, A verification reset spring (62) is provided between the verification slide (6) and the positioning slide (2); when the axial displacement difference exceeds the preset range, the verification slide (6) disengages from the lead reference feed sleeve (5), and the verification reset spring (62) causes the verification slide (6) to return to the initial position; in the preset continuous stroke, the stroke after the contact spring (41) stops transmitting force to the axial offset sleeve (4) is not less than one lead of the tap (321).

4. A tapping machine for metal parts processing according to claim 3, characterized in that, A floating fitting seat (43) is provided between the fitting spring (41) and the axial offset sleeve (4), and a fitting limiting shoulder (24) is fixed on the positioning slide (2); the floating fitting seat (43) pushes against the axial offset sleeve (4) under the action of the fitting spring (41), and the floating fitting seat (43) stops moving after reaching the fitting limiting shoulder (24), and the axial offset sleeve (4) continues to move into the hole and separates from the floating fitting seat (43).

5. A tapping machine for metal parts processing according to claim 4, characterized in that, The verification slide (6) is provided with a single-proof latch (61), and the lead reference feed sleeve (5) is provided with a single snap-fit ​​part that engages with the single-proof latch (61).

6. A tapping machine for metal parts processing according to claim 5, characterized in that, The axial offset sleeve (4) is provided with an actual stroke follower pin (46), and the single proof latch (61) is provided with a difference allowable groove (611). The end of the actual stroke follower pin (46) is provided with a roller that contacts the difference allowable groove (611). The two sides of the difference allowable groove (611) are inclined surfaces. When the axial displacement difference exceeds the preset range, the roller moves along the corresponding groove wall and pushes the single proof latch (61) to disengage from the locking part.

7. A tapping machine for metal parts processing according to claim 5, characterized in that, The axial offset sleeve (4) is provided with a return-reset surface (45), and the positioning slide (2) is provided with a reset lifting rod (27). When the axial offset sleeve (4) returns to the floating contact seat (43), the return-reset surface (45) pushes the reset lifting rod (27) to lift the single-proof latch (61) away from the locking part.

8. A tapping machine for metal parts processing according to claim 1, characterized in that, The input spindle (21) and the tap bearing mandrel (3) are provided with a torque limiting clutch (33) and a bidirectional cutting clutch (34), and the torque limiting clutch (33) forms the torque limiting transmission connection; the tap bearing mandrel (3) and the lead reference feed sleeve (5) are provided with an axial clamping member (52); the dual load transmission sleeve (7) is respectively driven by the bidirectional cutting clutch (34) and the axial clamping member (52), and the same axial stroke of the dual load transmission sleeve (7) makes the two engage.

9. A tapping machine for metal parts processing according to claim 8, characterized in that, A sturdy retainer (71) is provided between the lead reference feed sleeve (5) and the dual load transfer sleeve (7). The trigger end of the sturdy retainer (71) is in drive engagement with the verification slide (6). After being triggered, the sturdy retainer (71) maintains the engagement position of the dual load transfer sleeve (7). When the input spindle (21) reverses, it maintains the engagement of the bidirectional cutting clutch (34) and the axial clamping member (52).

10. A tapping machine for metal parts processing according to claim 9, characterized in that, The positioning slide (2) is provided with a non-rotating orifice reference sleeve (8) for determining the position of the workpiece orifice. The non-rotating orifice reference sleeve (8) is slidably provided with an outlet release ring (81). The outlet release ring (81) is in transmission cooperation with the double-stable retainer (71). A failure release spring (72) is provided between the lead reference feed sleeve (5) and the double load transmission sleeve (7). After the last meshing tooth of the tap (321) exits the orifice, the tap bearing mandrel (3) drives the orifice release ring (81) to release the holding of the bistable retainer (71), and the failure release spring (72) causes the dual load transfer sleeve (7) to return to the position where the bidirectional cutting clutch (34) and the axial clamping member (52) are disengaged.

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