GB2607397A

GB2607397A - Rolling plastic-forming device and method for internal thread

Info

Publication number: GB2607397A
Application number: GB2203477.1A
Authority: GB
Inventors: Zhao Shengdun; Zhang Shuowen; Zhang Dawei; Zhang Peng; Jiang Fei
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2021-03-15
Filing date: 2022-03-14
Publication date: 2022-12-07
Anticipated expiration: 2042-03-14
Also published as: CN113059098B; CN113059098A; GB2607397B; GB202203477D0

Abstract

The device includes a chuck subassembly 3, a driving motor 4, and an internal thread rolling mechanism 2, arranged on a base 1. The motor provides rotating power for the thread rolling mechanism, and both are fixed on the base. The chuck subassembly is slidably connected 13 to the base and can be close to or away from the thread rolling mechanism. The rolling mechanism includes a bull wheel (21, Figure 4) and groups of rolling subassemblies (22, Figure 3) uniformly distributed on the outside of the bull wheel in a circumferential direction. Each rolling subassembly includes a pinion 221 and a coaxial thread rolling die 222. The pinions, connected to the base and engaged with the bull wheel, drive the thread rolling dies to rotate. An excircle surface of the thread rolling die is of a formed thread structure. There is a phase difference between the thread structures of the thread rolling dies. The rolling dies can drive a workpiece 10 to axially rotate and axially feed to machine an internal thread on an inner ring of the workpiece. The internal thread rolling mechanism may include a circumferential vibration structure 26.

Description

ROLLING PLASTIC-FORMING DEVICE AND METHOD FOR INTERNAL

THREAD

TECHNICAL FIELD

100011 The present disclosure relates to the technical field of advanced material forming, in particular to a rolling plastic-forming device and method for an internal thread

BACKGROUND ART

100021 Internal thread parts are important components in mechanical equipment, which can be widely used in the equipment manufacturing industry as connector, fastener, and other parts. At present, internal thread cutting tapping, internal thread extrusion tapping, internal thread milling, and internal thread vibration cutting tapping processes are generally used for internal threads with a nominal diameter less than 24 mm. For large-diameter internal threads, that is, for internal threads with a nominal diameter greater than 24 mm, an extrusion forming process cannot be used. The main reasons are as follows: 100031 1. When a large-diameter internal thread is formed by extrusion, a forming torque is very large, which easily causes an extrusion tap to break.

100041 2. If the diameter of the extrusion tap used to machine the internal thread is larger, the difficulty in machining of the internal thread is higher, and its own size will increase sharply, resulting in high production cost.

100051 In order to solve the above-mentioned technical problems, a milling process is generally used to machine the large-diameter internal threads in the prior art. However, the internal thread milling process easily causes a waste of materials, and a fibrous structure of metal is cut off during the cutting, which easily reduces the performance of a material. Therefore, high-quality and efficient manufacturing of the large-diameter internal threads has become an urgent problem to be solved.

SUMMARY

100061 Embodiments of the present disclosure provide a rolling plastic-forming device and method for an internal thread, which can not only improve the machining efficiency and quality and has the advantages of saving materials and reducing a tapping torque and wear of a tap.

100071 In order to achieve the above-mentioned objective, on the one hand, an embodiment of the present disclosure provides a rolling plastic forming device for an internal thread, including a base, and a chuck subassembly, a driving motor and an internal thread rolling mechanism which are arranged on the base. The driving motor and the internal thread rolling mechanism are both fixed on the base, and the driving motor can provide rotating power for the internal thread rolling mechanism. The chuck subassembly is slidably connected to the base, and the chuck subassembly can be close to or away from the internal thread rolling mechanism. The internal thread rolling mechanism includes a bull wheel and a plurality of groups of rolling subassemblies uniformly distributed on the outer side of the bull wheel in a circumferential direction.

Each rolling subassembly includes a pinion and a thread rolling die which are coaxial with each other. The pinions are connected to the base and are engaged with the bull wheel. The pinions can drive the thread rolling dies to rotate. An excircle surface of the thread rolling die is of a formed thread structure, and there is a phase difference between the thread structures of the plurality of thread rolling dies.

100081 Further, each rolling subassembly further includes a connecting bolt and a shaft sleeve; the shaft sleeve is sleeved on the connecting bolt; the pinion and the thread rolling die are all sleeved on the shaft sleeve; the shaft sleeve may rotate relative to the connecting bolt, a first limiting structure and a second limiting structure are respectively arranged between the shaft sleeve and the pinion as well as between the shaft sleeve and the thread rolling die; the first limiting structure may prevent the thread rolling die from rotating around the shaft sleeve; and the second limiting structure may prevent the pinion from rotating around the shaft sleeve.

100091 Further, the internal thread rolling mechanism further includes a first end cover and a shell; one end of the connecting bolt passes through the first end cover, the shaft sleeve, and a first end of the shell in sequence and is then fastened with a nut; arid a second end of the shell is connected to the base.

[0010] Further, the internal thread rolling mechanism further includes a circumferential vibration structure; the base is provided with a first vertical plate; the shell is erected on the first vertical plate; the second end of the shell is connected to the circumferential vibration structure, and the circumferential vibration structure may drive the shell to circumferentially vibrate relative to the first vertical plate.

[0011] Further, the second end of the shell is provided with a second connecting part extending in a radial direction; the second connecting part is located on an outer wall surface of the shell and is perpendicular to an axis of the shell; the circumferential vibration structure includes a vibration motor, an eccentric wheel, and a connecting rod; the vibration motor is fixed on the first vertical plate; an output shaft of the vibration motor is connected to an input end of the eccentric wheel, an output end of the eccentric wheel is connected to one end of the connecting rod; and the other end of the connecting rod is connected to the second connecting part.

[0012] Further, the internal thread rolling mechanism further includes a second end cover fixedly connected to the first vertical plate; the second end cover covers the outer side of the shell; a gap is formed in the second end cover; and the connecting part extends out of the gap and is connected to the connecting rod.

[0013] Further, the first end of the shell is provided with a first connecting part; the first connecting part is a ring plate located in the shell; the first connecting part is lower than the end surface of the first end of the shell; a plurality of protrusions extending in an axial direction are arranged on the first end cover; each protrusion is located between two adjacent thread rolling dies, and an outer edge of the protrusion is lower than the excircle surface of the thread rolling die; the protrusion resists against the first end of the shell; a gear mounting cavity is formed among the protrusion, the first end of the shell, and the first connecting part; and the plurality of pinions are all mounted in the gear mounting cavity.

[0014] Further, the chuck subassembly includes a chuck and a second vertical plate; the chuck is connected to the second vertical plate through a connector; the connector is rotatable relative to the second vertical plate; the second vertical plate is slidably connected to the base; and a sliding direction of the second vertical plate overlaps the axis of the driving motor.

100151 In another aspect, an embodiment of the present disclosure provides a forming method based on the above-mentioned rolling plastic-forming device for an internal thread, including the following steps: Sl, fixing a blank on the chuck subassembly, and ensuring that the axis of the blank and the axis of the internal thread rolling mechanism are on the same straight line; S2, turning on the driving motor so that the driving motor rotates towards a first direction; S3, pushing the first vertical plate to move towards the internal thread rolling mechanism, and starting to machine threads until a thread in the blank is formed; and S4, controlling the driving motor to rotate towards a second direction, the second direction being opposite to the first direction.

100161 Further, after the step S2, the forming method further includes turning on the vibration motor; and after the step S3, the forming method further includes stopping the vibration motor.

100171 Compared with the prior art, the present disclosure has the following beneficial effects: 100181 1. In the present disclosure, a large-size internal thread is formed by rolling using a plurality of internal thread rolling dies. In the forming process, work hardening occurs. Compared with milling machining, the present disclosure improves the utilization rate of materials and the machining efficiency, and further overcomes the shortcoming of a decrease in the strength of a part due to the cutting off of fibers of the material and micro cracks of the material generated at a machined part in the milling forming process.

100191 2. In the present disclosure, the plurality of rolling subassemblies are driven by the circumferential vibration structure to vibrate in the circumferential direction. In the forming process, contact between the thread rolling dies in the rolling subassemblies and a blank changes periodically, which is favorable for the entry of lubricating oil, thus reducing the friction in the forming process and improving the surface quality of a formed part.

100201 3. By means of driving, by the same gear, the plurality of thread rolling dies to move and the blank to achieve self-feeding, the present disclosure ensures the synchronism of the movement of the plurality of thread rolling dies and simplifies the structure of the forming device.

BRIEF DESCRIPTION OF THE DRAWINGS

100211 In order to describe the embodiments of the present disclosure or the technical solutions in the prior art more clearly, drawings required to be used in the embodiments or the illustration of the existing art will be briefly introduced below. Obviously, the drawings in the illustration below are only some embodiments of the present disclosure Those ordinarily skilled in the art also can acquire other drawings according to the provided drawings without creative work.

100221 FIG. 1 is a three-dimensional schematic structural diagram 1 of a rolling plastic-forming device for an internal thread according to an embodiment of the present disclosure; 100231 FIG. 2 is a three-dimensional schematic structural diagram 2 of a rolling plastic-forming device for an internal thread according to an embodiment of the present disclosure; 100241 FIG. 3 is a three-dimensional schematic structural diagram I of an internal thread rolling mechanism in a rolling plastic-forming device for an internal thread according to an embodiment of the present disclosure; 100251 FIG. 4 is a three-dimensional schematic structural diagram 2 (without a shell) of an internal thread rolling mechanism in a rolling plastic-forming device for an internal thread according to an embodiment of the present disclosure; 10026] FIG. 5 is a schematic diagram of a connection structure between an internal thread rolling mechanism and a first vertical plate in a rolling plastic-forming device for an internal thread according to an embodiment of the present disclosure; 100271 FIG. 6 is an exploded schematic structural diagram of a rolling subassembly in a rolling plastic-forming device for an internal thread according to an embodiment of the present disclosure; 100281 FIG. 7 is sectional view of a chuck subassembly in a rolling plastic-forming device for an internal thread according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

100291 The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments Based on the embodiments in present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

100301 In the description of the present invention, it should be understood that orientations or positional relationships indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like are orientations or positional relationships as shown in the drawings, and are only for the purpose of facilitating and simplifying the description of the present invention instead of indicating or implying that devices or elements indicated must have particular orientations, and be constructed and operated in the particular orientations, so that these terms are not construed as limiting the present invention 100311 In the description of the present disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "mounted", "communicated" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection, or an integral connection For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood in specific situations.

100321 The terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, features defined by "first" and "second" can explicitly instruct or impliedly include one or more features. In the description of the present disclosure, unless otherwise indicated, "plurality" means two or more.

100331 Referring to FIG. 1 and FIG. 2, an embodiment of the present disclosure provides a rolling plastic-forming device for an internal thread. The forming device includes a base 1 and a driving motor 4, an internal thread rolling mechanism 2 and a chuck subassembly 3 which are arranged on the base 1. The driving motor 4 and the internal thread rolling mechanism 2 are both fixed on the base 1, and the driving motor 4 can provide rotating power for the internal thread rolling mechanism 2. The chuck subassembly 3 is slidably connected to the base 1, and the chuck subassembly 3 is used for clamping a workpiece 10. The chuck subassembly 3 can be close to or away from the internal thread rolling mechanism 2. The embodiment of the present disclosure is used for machining a large-size internal thread having a diameter greater than 24 mm. 100341 Referring to FIG. 3 to FIG. 5, the internal thread rolling mechanism 2 includes a bull wheel 21 and a plurality of groups of rolling subassemblies 22 uniformly distributed on the outer side of the bull wheel 21 in a circumferential direction. In some examples, in order to make the structure simpler and the workpiece 10 more uniformly stressed, there are three groups of rolling subassemblies 22. Specifically, each rolling subassembly 22 includes a pinion 221 and a thread rolling die 222 which are coaxial with each other. The pinion 221 is connected to the base 1 and is engaged with the bull wheel 21. The bull wheel is sleeved on a gear shaft 28, and the gear shaft 28 is connected to the driving motor 4. The pinion 221 can drive the thread rolling die 222. An excircle surface of the thread rolling die 222 is of a formed thread structure, and there is a phase difference between the thread structures of the three rolling dies 222. Therefore, when the three pinions 221 respectively drive the corresponding thread rolling dies 222 to rotate, the three thread rolling dies 222 can drive the workpiece 10 to axially rotate and axially feed, thus machining an internal thread on an inner ring of the workpiece 10.

100351 Referring to FIG. 6, the rolling subassembly 22 further includes a connecting bolt 223 and a shaft sleeve 224.The shaft sleeve 224 is sleeved on the connecting bolt 223. The pinion 221 and the thread rolling die 222 are all sleeved on the shaft sleeve 224. The shaft sleeve 224 may rotate relative to the connecting bolt 223. A first limiting structure and a second limiting structure are respectively arranged between the shaft sleeve 224 and the pinion 221 as well as between the shaft sleeve 221 and the thread rolling die 222. The first limiting structure may prevent the thread rolling die 222 from rotating around the shaft sleeve 224; and the second limiting structure may prevent the pinion 221 from rotating around the shaft sleeve 224.

100361 Specifically, the first limiting structure includes a third plane 2241 arranged on the excircle surface of the shaft sleeve 224 and a first plane 2211 which is arranged on the pinion 221 and faces the third plane 2241. The first plane 2211 resists against the third plane 2241. The second limiting structure includes a fourth plane 2242 arranged on the excircle surface of the shaft sleeve 224 and a fourth plane 2221 which is arranged on the thread rolling die 222 and faces the fourth plane 2242. The second plane 2221 resists against the fourth plane 2242.

100371 Referring to FIG. 3 and FIG. 5, the internal thread rolling mechanism 2 further includes a first end cover 23 and a shell 24. A first end of the shell 24 is provided with a first connecting part 241. The first connecting part 241 is a ring plate located in the shell 24. The first connecting part 241 is lower than the end surface of the first end of the shell 24. A plurality of protrusions 231 extending in the axial direction are arranged on the first end cover 23. Each protrusion 231 is located between two adjacent thread rolling dies 222, and an outer edge of the protrusion 231 is lower than the excircle surface of the thread rolling die 222. The protrusion 231 resists against the first end of the shell 24. A gear mounting cavity 25 is formed among the protrusion 231, the first end of the shell 24, and the first connecting part 241. The three pinions 221 are all mounted in the gear mounting cavity 25. One end of the connecting bolt 223 passes through the first end cover 23, the shaft sleeve 224, and the first end of the shell 24 in sequence and is then fastened with a nut 29. A second end of the shell 24 is connected to the base 1. Thus, the strength of the internal thread rolling mechanism 2 can be improved, and the three pinions 221 can be prevented from being collided with a foreign matter.

100381 It should be noted that a sum of the height of the protrusion 231 and the height of the part of the first end of the shell 24 higher than the first connecting part 241 should be greater than a sum of the thicknesses of the pinion 221 and the thread rolling die 222. Thus, a failure in rotation due to the fact that the thread rolling die 222 and the pinion 221 are clamped between the first end cover 23 and the first connecting part 241 can be prevented.

100391 Referring to FIG. 1, FIG. 2, and FIG. 5, in some embodiments, the internal thread rolling mechanism 2 further includes a circumferential vibration structure 26. The base 1 is provided with a first vertical plate 11. The shell 24 is erected on the first vertical plate 11. A first bearing 6 is mounted between the excircle surface of the shell 24 and an inner hole of the first vertical plate 11. The second end of the shell 24 is connected to the circumferential vibration structure 26. The circumferential vibration structure 26 may drive the shell 24 to circumferentially vibrate relative to the vertical plate. In the forming process, contact between the thread rolling dies 222 in the rolling subassemblies 22 and a blank 10 changes periodically, which is favorable for the entry of lubricating oil, thus reducing the friction in the forming process and improving the surface quality of a formed part.

100401 Referring to FIG. 5, specifically, a stepped hole is formed in the first vertical plate 11. The second end of the shell 24 is provided with a flanging 244. The first bearing 6 is pressed on the flanging 244 and the end surface of the stepped hole. A second connecting part 245 extending in the radial direction is arranged on the flanging 244. The second connecting part 245 is located on an outer wall surface of the shell 24 and is perpendicular to an axis of the shell 24.

100411 Referring to FIG. 1 and FIG. 2, the circumferential vibration structure 26 includes a vibration motor 261, an eccentric wheel 262, and a connecting rod 263. The vibration motor 261 is fixed on the first vertical plate 11. An output shaft of the vibration motor 261 is connected to an input end of the eccentric wheel 262. An output end of the eccentric wheel 262 is connected to one end of the connecting rod 263. The other end of the connecting rod 263 is connected to the second connecting part 245.

100421 Referring to FIG. 7, the internal thread rolling mechanism 2 further includes a second end cover 27 fixedly connected to the first vertical plate 11. The second end cover 27 covers the outer side of the shell 24 and presses the shell 24 on the first vertical plate 11. A gap 271 is formed in the second end cover 27. The second connecting part 245 extends out of the gap 271 and is connected to the connecting rod 263. In order to prevent the second connecting part 245 from being damaged, a groove 111 is further formed in the first vertical plate 11, and the second connecting part 245 is located in the groove 111.

100431 Referring to FIG. 1 and FIG. 5, in some embodiments, a motor support 12 is arranged on the base 1. The driving motor 4 is fixed on the base 1 through the motor support 12. An output shaft of the driving motor 4 is connected to the gear shaft 28 through a coupling 5. In some embodiments, in order to facilitate machining, the gear shaft 28 and the bull wheel 21 are one-piece members.

100441 Referring to FIG. 1 and FIG. 7, the chuck subassembly 3 includes a chuck 31 and a second vertical plate 32. The chuck 31 is connected to the second vertical plate 32 through a connector 33. The connector 33 is connected with the second vertical plate 32 through a second bearing 34. A third end cover 35 is arranged on an end surface of the second bearing 34. A sliding rail 13 is arranged on the base 1. An extending direction of the sliding rail 13 is parallel to an axis of the chuck 3. A sliding chute 321 matched with the sliding rail 13 is arranged on the second vertical plate 32. Thus, during machining of an internal thread, the chuck 3 can achieve automatic feeding.

100451 In another aspect, an embodiment of the present disclosure provides a forming method based on the above-mentioned rolling plastic-forming device for an internal thread, including the following steps: 100461 step I, fixing a blank on the chuck subassembly, and ensuring that the axis of the blank and the axis of the internal thread rolling mechanism are on the same straight line; 100471 step II, turning on the driving motor so that the driving motor rotates towards a first direction; 100481 step II, turning on the vibration motor; 100491 step IV, pushing the chuck subassembly to move towards the internal thread rolling mechanism, and starting to machine threads until a thread in the blank is formed; 100501 step V. stopping the vibration motor, and 100511 step VI, controlling the driving motor to rotate towards a second direction, the second direction being opposite to the first direction.

100521 The above are only specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present disclosure should fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to that of the appended claims.

Claims

WHAT IS CLAIMED IS: I. A rolling plastic-forming device for an internal thread, comprising a base, and a chuck subassembly, a driving motor and an internal thread rolling mechanism which are arranged on the base, wherein the driving motor and the internal thread rolling mechanism are both fixed on the base, and the driving motor may provide rotating power for the internal thread rolling mechanism; the chuck subassembly is slidably connected to the base, and the chuck subassembly may be close to or away from the internal thread rolling mechanism; the internal thread rolling mechanism comprises a bull wheel and a plurality of groups of rolling subassemblies uniformly distributed on the outer side of the bull wheel in a circumferential direction; each rolling subassembly comprises a pinion and a thread rolling die which are coaxial with each other; the pinions are connected to the base and are engaged with the bull wheel; the pinions may drive the thread rolling dies to rotate; an excircle surface of the thread rolling die is of a formed thread structure, and there is a phase difference between the thread structures of the plurality of thread rolling dies.
2. The rolling plastic-forming device for the internal thread according to claim 1, wherein each rolling subassembly further comprises a connecting bolt and a shaft sleeve; the shaft sleeve is sleeved on the connecting bolt; the pinion and the thread rolling die are all sleeved on the shaft sleeve; the shaft sleeve may rotate relative to the connecting bolt; a first limiting structure and a second limiting structure are respectively arranged between the shaft sleeve and the pinion as well as between the shaft sleeve and the thread rolling die; the first limiting structure may prevent the thread rolling die from rotating around the shaft sleeve; and the second limiting structure may prevent the pinion from rotating around the shaft sleeve.
3. The rolling plastic-forming device for the internal thread according to claim 2, wherein the internal thread rolling mechanism further comprises a first end cover and a shell; one end of the connecting bolt passes through the first end cover, the shaft sleeve, and a first end of the shell in sequence and is then fastened with a nut, and a second end of the shell is connected to the base
4. The rolling plastic-forming device for the internal thread according to claim 3, wherein the internal thread rolling mechanism further comprises a circumferential vibration structure; the base is provided with a first vertical plate; the shell is erected on the first vertical plate; the second end of the shell is connected to the circumferential vibration structure, and the circumferential vibration structure may drive the shell to circumferentially vibrate relative to the first vertical plate.
5. The rolling plastic-forming device for the internal thread according to claim 4, wherein the second end of the shell is provided with a second connecting part extending in a radial direction, the second connecting part is located on an outer wall surface of the shell and is perpendicular to an axis of the shell; the circumferential vibration structure comprises a vibration motor, an eccentric wheel, and a connecting rod; the vibration motor is fixed on the first vertical plate; an output shaft of the vibration motor is connected to an input end of the eccentric wheel; an output end of the eccentric wheel is connected to one end of the connecting rod; and the other end of the connecting rod is connected to the second connecting part.
6. The rolling plastic-forming device for the internal thread according to claim 5, wherein the internal thread rolling mechanism further comprises a second end cover fixedly connected to the first vertical plate; the second end cover covers the outer side of the shell; a gap is formed in the second end cover; and the connecting part extends out of the gap and is connected to the connecting rod.
7. The rolling plastic-forming device for the internal thread according to claim 6, wherein the first end of the shell is provided with a first connecting part; the first connecting part is a ring plate located in the shell; the first connecting part is lower than the end surface of the first end of the shell; a plurality of protrusions extending in an axial direction are arranged on the first end cover; each protrusion is located between two adjacent thread rolling dies, and an outer edge of the protrusion is lower than the excircle surface of the thread rolling die; the protrusion resists against the first end of the shell; a gear mounting cavity is formed among the protrusion, the first end of the shell, and the first connecting part; and the plurality of pinions are all mounted in the gear mounting cavity.
8. The rolling plastic-forming device for the internal thread according to any one of claims 1 to 7, wherein the chuck subassembly comprises a chuck and a second vertical plate; the chuck is connected to the second vertical plate through a connector; the connector is rotatable relative to the second vertical plate; the second vertical plate is slidably connected to the base; and a sliding direction of the second vertical plate overlaps the axis of the driving motor.
9. A forming method based on the rolling plastic-forming device for an internal thread according to any one of claims 1 to 8; comprising the following steps: SI, fixing a blank on the chuck subassembly, and ensuring that the axis of the blank and the axis of the internal thread rolling mechanism are on the same straight line; S2, turning on the driving motor so that the driving motor rotates towards a first direction; S3, pushing the first vertical plate to move towards the internal thread rolling mechanism, and starting to machine threads until a thread in the blank is formed; and S4, controlling the driving motor to rotate towards a second direction, the second direction being opposite to the first direction.
10. The forming method for the internal thread according to claim 9, wherein after the step S2, the forming method further comprises turning on the vibration motor; and after the step 53, the forming method further comprises stopping the vibration motor.