An electric pipe expander with floating pipe expansion effective stroke

Abstract

The electric pipe expander with floating effective pipe expanding stroke comprises an expander main body, a chuck body, a clamping wrench and a hand-held body. A sampling resistor for detecting real-time current and / or real-time voltage of a motor is connected to the lower end surface of a circuit board. A non-contact sensor is used to detect the number of rotations of a magnetic ring and convert it into a pulse signal. A control chip is used to control the rotation of the motor. When the pipe expanding cone is at the intersection of the invalid pipe expanding stroke and the effective pipe expanding stroke, the sampling resistor detection value gradually increases. The control chip starts recording the pulse signal and compares it with the set value. When the pulse signal reaches the set value, the control chip controls the motor to stop rotating and reset, and the pipe expanding operation is completed. The electric pipe expander can use the detection value of the sampling circuit as the starting time of recording the pulse signal, thereby avoiding the interference of the invalid pipe expanding stroke and realizing the floating of the effective pipe expanding stroke. When the pipe wall thickness changes, the pipe expanding operation with a set distance can still be realized.

Description

Technical Field

[0001] This invention belongs to the field of pipe expander technology, and specifically relates to an electric pipe expander with a floating effective expansion stroke. Background Technology

[0002] A tube expander is a tool used in the manufacture and repair of various containers to enlarge the inner and outer diameters of tubes, ensuring a tight seal between the tube and the tube sheet, preventing air leakage, and enabling the tube to withstand certain pressure. It is widely used in the manufacture and repair of boilers, heat exchangers, condensers, coolers, and other pressure vessels in industries such as petroleum, chemical, power, metallurgy, shipbuilding, and refrigeration. For example, during the installation or repair of air conditioners, a tube expander is used to flare the refrigerant copper tubes.

[0003] Existing pipe expanders are generally divided into two main categories: manual pipe expanders and electric pipe expanders. The former is characterized by its small size and light weight, but it requires one hand to hold and the other to rotate the knob when expanding the pipe, which is complicated, time-consuming and labor-intensive. The latter only requires clamping the pipe end with the clamp and pressing the start button to complete the pipe expansion operation, which is simple, convenient, time-saving and labor-saving and highly efficient.

[0004] The expansion stroke is the distance the mandrel and expanding cone of an electric expander move forward during the expansion process. It is a crucial indicator for ensuring the expansion effect. If this distance is too short, the expansion may be incomplete; if it is too long, the tube wall may crack. Existing technologies generally control this distance in two ways. The first uses a mechanical clutch structure, as disclosed in Chinese patent CN219966220U. However, this solution has a large and heavy control system. In actual operation, it requires judging whether expansion is complete based on the mechanical sound of the expander, and then manually controlling the motor direction. This places high demands on the user and limits automation. The first method has low accuracy, and human factors have a significant impact on the tube expansion effect, resulting in poor consistency. The second method uses intelligent control circuits, such as the electric tube expander disclosed in Chinese patent CN209969402U. This solution mainly relies on a position detection switch set on the rear cover of the expander body to determine the initial position of the expander head, and then moves the expander head forward a set distance from the initial position to complete the expansion. However, the expander head is not in contact with the tube body to be expanded at the initial position, and needs to move forward a certain distance to make contact (reach the contact position). This distance is actually an ineffective expansion stroke. When the wall thickness of the tube body to be expanded changes, such as... Figure 1As shown, this distance will change by ΔX, while the total forward distance (the distance from the starting position to the ending position of the expansion tube) remains unchanged. This causes the effective stroke of the expansion tube (the distance from the contact position to the ending position of the expansion tube) to change, resulting in different pipe diameters D1 and D2 after expansion. When the pipe diameters are not much different (within 0.2mm), the connection can still be achieved by compensating with the locking part's allowance or by forcibly pushing the tube. However, when the pipe diameters differ greatly, the connection is basically impossible to achieve, and the tube needs to be expanded again, which is inconvenient. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an electric expander with a floating expander effective stroke.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is an electric pipe expander with a floating effective expansion stroke, comprising:

[0007] The tube expander body includes a housing extending horizontally in the left-right direction, a worm gear rotatably disposed within the housing, a mandrel movable left-right through the central hole of the worm gear, a guide screw fixedly connected to the inner wall of the right side of the housing, and a tube expander cone eccentrically connected to the left end of the mandrel. The left side of the housing has an opening for exposing the mandrel and the tube expander cone. The mandrel rotates synchronously with the worm gear. A limiting key is inserted radially at the rear end of the mandrel. The end of the limiting key protruding from the outer wall of the mandrel is inserted into a groove milled axially in the inner wall of the central hole of the worm gear. The guide screw is coaxially disposed with the mandrel. The left end of the guide screw is inserted into the central hole of the mandrel and threadedly connected to it. When the mandrel rotates with the worm gear, the mandrel moves left and right under the action of the threaded connection.

[0008] A chuck body is connected to the left end face of the housing. The chuck body has a tube expansion cavity at its center aligned with the opening. The chuck body is used to clamp the tube to be expanded.

[0009] A clamping wrench is rotatably connected to the chuck body. The clamping wrench is used to drive the chuck body to open and close, so as to lock or loosen the tube body to be expanded.

[0010] A handheld device is connected to the lower end of the expansion tube body. The upper end of the handheld device is provided with a motor and a circuit board for driving the worm gear to rotate, and the lower end of the handheld device is provided with a battery for supplying power to the motor and the circuit board.

[0011] The motor is a dual-head motor. The upper output shaft of the motor is connected to a worm gear that meshes with the worm wheel via a coupling. A magnetic ring is sleeved on the lower output shaft of the motor. The circuit board is located below the motor. The center of the circuit board has a through hole for the lower output shaft of the motor to pass through. The magnetic ring is located below the circuit board.

[0012] The lower end face of the circuit board is connected to a sampling resistor for detecting the real-time current and / or real-time voltage of the motor, a non-contact sensor for detecting the number of rotations of the magnetic ring and converting it into a pulse signal, and a control chip for controlling the rotation of the motor. The control chip is electrically connected to the sampling resistor and the non-contact sensor. When the tube expanding cone is at the junction of the tube expanding ineffective stroke and the tube expanding effective stroke, the detection value of the sampling resistor gradually increases. The control chip records the pulse signal sent by the non-contact sensor and compares it with a set value. When the pulse signal reaches the set value, the control chip controls the motor to stop rotating and reset, completing the tube expanding operation.

[0013] Preferably, the control chip is an STM32F103C6T6 microcontroller, the PA1 pin of the control chip is connected to one end of the sampling resistor, and the PA6 pin of the control chip is connected to the non-contact sensor through a noise reduction diode Q7.

[0014] More preferably, the non-contact sensor is a Hall sensor, the first pin of the Hall sensor is connected to the noise reduction diode Q7 through resistor R2, the second pin of the Hall sensor is grounded, and the third pin of the Hall sensor is connected to VCC 12V power supply.

[0015] More preferably, a resistor R1 is connected in parallel with the Hall sensor, one end of which is connected to the connection line between the VCC 12V power supply and the Hall sensor, and the other end is connected to the connection line between the resistor R2 and the Hall sensor.

[0016] More preferably, the lower end face of the circuit board is also connected to a MOS transistor for forming a full-bridge circuit to drive the motor to rotate. One end of the sampling resistor is connected to the full-bridge circuit, and the other end is grounded. A capacitor C2 is connected in parallel with the sampling resistor.

[0017] Preferably, during the pipe expansion operation, the control chip separately records the pulse signals sent by the non-contact sensor from the start to the present.

[0018] Preferably, the housing includes a right housing that is closed at the right end, and a left housing that covers the left end of the right housing, with the opening located on the left end face of the left housing.

[0019] Preferably, a transmission nut is threaded onto the guide screw, the transmission nut is located on the right side of the mandrel, and a transmission nut seat for abutting the transmission nut is provided on the right inner wall of the housing.

[0020] Preferably, there are two limiting keys, which are symmetrically distributed along the axis of the mandrel.

[0021] Preferably, the expanding cone is rotatably connected to the left end of the mandrel via a cone bearing.

[0022] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0023] The present invention provides an electric expander with a floating expander effective stroke, comprising an expander body, a chuck body, a clamping wrench, and a handheld body. The upper end of the handheld body is equipped with a motor and a circuit board for driving the worm gear in the expander body, and the lower end of the handheld body is equipped with a battery for supplying power to the motor and circuit board. The motor is a dual-head motor, with its upper output shaft connected to a worm gear meshing with the worm gear. A magnetic ring is fitted onto the lower output shaft of the motor. The circuit board is positioned below the motor, with a through hole at its center for the lower output shaft to pass through, placing the magnetic ring below the circuit board. A sampling resistor is connected to the lower end face of the circuit board for detecting the real-time current and / or real-time voltage of the motor, and for detecting the number of rotations of the magnetic ring and converting it into a pulse signal. A non-contact sensor and a control chip for controlling motor rotation are electrically connected to the sampling resistor and the non-contact sensor. When the expanding cone is at the junction of the ineffective and effective expansion strokes, the detection value of the sampling resistor gradually increases. The control chip records the pulse signal sent by the non-contact sensor and compares it with the set value. When the pulse signal reaches the set value, the control chip controls the motor to stop rotating and reset, completing the expansion operation. The control chip can use the detection value of the sampling circuit as the starting point for recording the pulse signal, thereby avoiding interference from the ineffective expansion stroke and realizing the floating of the effective expansion stroke. Even when the wall thickness of the tube to be expanded changes, the expansion operation at the set distance can still be achieved. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the expansion stroke when the wall thickness of the pipe to be expanded changes in the existing technology.

[0025] Figure 2 This is a front view schematic diagram of a preferred embodiment of the present invention.

[0026] Figure 3 yes Figure 2 A left-side view diagram.

[0027] Figure 4 yes Figure 2A top-down view.

[0028] Figure 5 yes Figure 2 Cross-sectional view along the AA direction.

[0029] Figure 6 yes Figure 3 Cross-sectional view along the BB direction.

[0030] Figure 7 yes Figure 4 A cross-sectional view along the CC direction, showing the mandrel and expanding cone in their initial positions.

[0031] Figure 8 yes Figure 4 A cross-sectional view along the CC direction, showing the mandrel and the expanding cone at their extreme positions (farthest expanding position).

[0032] Figure 9 yes Figure 4 A cross-sectional view along the CC direction, showing the expanding cone in contact with the tube body to be expanded.

[0033] Figure 10 yes Figure 4 A cross-sectional view along the CC direction, showing the expanding cone in position after the expanding operation is completed.

[0034] Figure 11 yes Figure 6 The circuit diagram of the control circuit containing the control chip on the circuit board.

[0035] Figure 12 yes Figure 6 The circuit diagram of the sampling circuit where the sampling resistor is located.

[0036] Figure 13 yes Figure 6 The circuit diagram of the detection circuit containing the Hall sensor.

[0037] The components are as follows: 1. Tube body; 10. Expanding tube body; 11. Shell; 111. Right shell; 112. Left shell; 113. Transmission nut seat; 12. Worm gear; 121. Worm gear center hole; 122. Slide groove; 13. Mandrel; 131. Limit key; 132. Center hole; 14. Guide screw; 141. Transmission nut; 15. Expanding tube cone; 151. Conical bearing; 16. Opening; 20. Chuck body; 21. Expanding tube cavity; 30. Clamping wrench; 40. Handheld body; 41. Motor; 411. Upper output shaft; 412. Coupling; 413. Worm gear; 414. Lower output shaft; 415. Magnetic ring; 42. Circuit board; 421. Through hole; 422. Sampling resistor; 423. Hall sensor; 424. Control chip; 425. MOSFET; 43. Battery. Detailed Implementation

[0038] like Figures 2 to 13As shown, the electric expander with a floating expander effective stroke provided by the present invention includes an expander body 10, a chuck body 20, a clamping wrench 30, and a handheld body 40; wherein, the expander body 10 includes a housing 11 extending horizontally in the left-right direction, a worm gear 12 rotatably disposed in the housing 11, a spindle 13 movably inserted into the worm gear center hole 121 of the worm gear 12, a guide screw 14 fixedly connected to the inner wall of the right side of the housing 11, and an expander cone eccentrically connected to the left end of the spindle 13. 15; The left side of the housing 11 is provided with an opening 16 for exposing the mandrel 13 and the expanding tube cone 15. The housing 11 includes a right housing 111 closed at the right end and a left housing 112 covering the left end of the right housing 111. The opening 16 is located on the left end face of the left housing 112. The mandrel 13 rotates synchronously with the worm gear 12. A limiting key 131 is inserted into the rear end of the mandrel 13 in the radial direction. The end of the limiting key 131 protruding from the outer wall of the mandrel 13 is inserted into the groove 122 milled axially on the inner wall of the worm gear center hole 121. The guide screw 14 is coaxially arranged with the spindle 13. The left end of the guide screw 14 is inserted into the center hole 132 of the spindle 13 and threadedly connected to it. When the spindle 13 rotates with the worm gear 12, the spindle 13 moves left and right under the action of the threaded connection. A transmission nut 141 is threaded on the guide screw 14. The transmission nut 141 is located on the right side of the spindle 13. The inner wall of the right side of the right housing 111 is provided with a transmission nut seat 113 for abutting the transmission nut 141. The chuck body 20 is connected to the left end face of the housing 10. The chuck body 20 has a tube expansion cavity 21 aligned with the opening 16 at its center. The chuck body 20 is used to clamp the tube body 1 to be expanded. The clamping wrench 30 is rotatably connected to the chuck body 20. The clamping wrench 30 is used to drive the chuck body 20 to open and close, so as to lock or release the tube body 1 to be expanded. The hand-held body 40 is connected to the lower end of the tube expansion body 10 and extends vertically downward. The upper end of the hand-held body 40 is provided with a motor 41 and a circuit board 42. The lower end of the hand-held body 40 is provided with a battery 43 for supplying power to the motor 41 and the circuit board 42.Motor 41 drives worm gear 12 to rotate. Motor 41 is a double-headed motor. The upper output shaft 411 of motor 41 is connected to a worm 413 that meshes with worm gear 12 via coupling 412, which makes the power transmission structure more compact. In other embodiments, the upper output shaft 411 of motor 41 can also drive worm gear 12 to rotate through other transmission methods. A magnetic ring 415 is sleeved on the lower output shaft 414 of motor 41. The magnetic ring 415 is a surface-filled multi-pole plastic magnetic encoder magnetic ring or a radial multi-pole plastic magnetic encoder magnetic ring. The magnetic field distribution on the magnetic ring 415 is periodic. With the center of the magnetic ring 415 as the center and its radius as the limit, the magnetic ring 415 can be divided into multiple equal-area sector regions. Each sector region corresponds to one encoding cycle. Circuit board 42 is located below motor 41. The center of circuit board 42 is provided with a motor... The lower output shaft 414 passes through a through hole 421. A magnetic ring 415 is located below the circuit board 42. The lower end face of the circuit board 42 is connected to a sampling resistor 422 for detecting the real-time current and / or real-time voltage of the motor 41, a Hall sensor 423 for detecting the number of rotations of the magnetic ring 415 and converting it into a pulse signal, and a control chip 424 for controlling the rotation of the motor 41. The control chip 424 is electrically connected to the sampling resistor 422 and the Hall sensor 423. When the expanding cone 15 is at the junction of the ineffective and effective expansion strokes, the detection value of the sampling resistor 422 gradually increases. The control chip 424 records the pulse signal sent by the Hall sensor 423 and compares it with a set value. When the pulse signal reaches the set value, the control chip 424 controls the motor 41 to stop rotating and reset, completing the expansion operation.

[0039] The advantage of this setup is that the detection value of the sampling circuit can be used as the starting point for the control chip to record the pulse signal, thereby avoiding interference from the invalid stroke of the tube expansion and realizing the floating of the effective stroke of the tube expansion. Even when the wall thickness of the tube to be expanded changes, the tube expansion operation at the set distance can still be achieved.

[0040] In this embodiment, the control chip 424 is an STM32F103C6T6 microcontroller. The PA1 pin of the control chip 424 is connected to one end of the sampling resistor 422 (R0). The PA6 pin of the control chip 424 is connected to the Hall sensor 423 via a noise-reducing diode Q7. Specifically, the first pin of the Hall sensor 423 is connected to the noise-reducing diode Q7 via a resistor R2, the second pin of the Hall sensor 423 is grounded, and the third pin of the Hall sensor 423 is connected to the VCC 12V power supply. A resistor R1 is also connected in parallel with the Hall sensor 423, with one end of R1 connected in parallel to VCC. The 12V power supply is connected to the Hall sensor 423, and the other end is connected to the connection line between the resistor R2 and the Hall sensor 423. The lower end of the circuit board 42 is also connected to the MOS transistor 425, which is used to form a full-bridge circuit for driving the motor to rotate. One end of the sampling resistor 422 (R0) is connected to the full-bridge circuit, and the other end is grounded. A capacitor C2 is connected in parallel with the sampling resistor 422 (R0).

[0041] In this embodiment, there are two limiting keys 131, which are symmetrically distributed along the axis of the spindle 13. The expanding tube cone 15 is rotatably connected to the left end of the spindle 13 through the cone bearing 151.

[0042] Of course, to meet other needs, the control chip 424 can also use other types of microcontrollers, logic program controllers and other components.

[0043] In another embodiment, during the tube expansion operation, the control chip 424 also records the pulse signals sent by the Hall sensor 423 from the start to the current position. The advantage of this setting is that when the battery 43 is depleted, the pulse data corresponding to the current position can be recorded. After replacing the battery 43 or restoring the battery 43, the current position can be quickly found and the tube expansion operation can continue. Of course, in order to avoid excessive load on the motor 41, after finding the current position, the control chip 424 first controls the motor 41 to reverse the direction by a set number of revolutions or a set time, so that the tube expansion cone 15 retracts until it is completely separated from the tube body 1 to be expanded, and then controls the motor 41 to rotate forward to continue the tube expansion operation.

[0044] In another embodiment, when the expanding cone 15 is in the effective expanding stroke, the control chip 424 also records the rate of change of the value detected by the sampling resistor 422, compares it with the rate of change (empirical value) input to the control chip 424 in advance, obtains the empirical value of the effective expanding stroke under the rate of change, and dynamically adjusts the actual effective expanding stroke of the expanding cone 15 according to the empirical value.

[0045] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An electric expander with a floating expander effective stroke, comprising: The tube expander body includes a housing extending horizontally in the left-right direction, a worm gear rotatably disposed within the housing, a mandrel movable left-right through the central hole of the worm gear, a guide screw fixedly connected to the inner wall of the right side of the housing, and a tube expander cone eccentrically connected to the left end of the mandrel. The left side of the housing has an opening for exposing the mandrel and the tube expander cone. The mandrel rotates synchronously with the worm gear. A limiting key is inserted radially at the rear end of the mandrel. The end of the limiting key protruding from the outer wall of the mandrel is inserted into a groove milled axially in the inner wall of the central hole of the worm gear. The guide screw is coaxially disposed with the mandrel. The left end of the guide screw is inserted into the central hole of the mandrel and threadedly connected to it. When the mandrel rotates with the worm gear, the mandrel moves left and right under the action of the threaded connection. A chuck body is connected to the left end face of the housing. The center of the chuck body is provided with a tube expansion cavity aligned with the opening. The chuck body is used to clamp the tube to be expanded. A clamping wrench is rotatably connected to the chuck body. The clamping wrench is used to drive the chuck body to open and close, so as to lock or loosen the tube body to be expanded. A handheld device is connected to the lower end of the expansion tube body. The upper end of the handheld device is provided with a motor and a circuit board for driving the worm gear to rotate, and the lower end of the handheld device is provided with a battery for supplying power to the motor and the circuit board. Its features are: The motor is a dual-head motor. The upper output shaft of the motor is connected to a worm gear that meshes with the worm wheel via a coupling. A magnetic ring is sleeved on the lower output shaft of the motor. The circuit board is located below the motor. The center of the circuit board has a through hole for the lower output shaft of the motor to pass through. The magnetic ring is located below the circuit board. The lower end face of the circuit board is connected to a sampling resistor for detecting the real-time current and / or real-time voltage of the motor, a non-contact sensor for detecting the number of rotations of the magnetic ring and converting it into a pulse signal, and a control chip for controlling the rotation of the motor. The control chip is electrically connected to the sampling resistor and the non-contact sensor. When the tube expanding cone is at the junction of the tube expanding ineffective stroke and the tube expanding effective stroke, the detection value of the sampling resistor gradually increases. The control chip records the pulse signal sent by the non-contact sensor and compares it with a set value. When the pulse signal reaches the set value, the control chip controls the motor to stop rotating and reset, completing the tube expanding operation.

2. The electric expander with floating expander effective stroke according to claim 1, characterized in that: The control chip is an STM32F103C6T6 microcontroller. The PA1 pin of the control chip is connected to one end of the sampling resistor, and the PA6 pin of the control chip is connected to the non-contact sensor through the noise reduction diode Q7.

3. The electric expander with floating expansion effective stroke according to claim 2, characterized in that: The non-contact sensor is a Hall sensor. The first pin of the Hall sensor is connected to the noise reduction diode Q7 through resistor R2, the second pin of the Hall sensor is grounded, and the third pin of the Hall sensor is connected to VCC 12V power supply.

4. The electric expander with floating expander effective stroke according to claim 3, characterized in that: A resistor R1 is also connected in parallel to the Hall sensor. One end of the resistor R1 is connected to the connection line between the VCC 12V power supply and the Hall sensor, and the other end is connected to the connection line between the resistor R2 and the Hall sensor.

5. The electric expander with floating expander effective stroke according to claim 2, characterized in that: The lower end of the circuit board is also connected to a MOS transistor for forming a full-bridge circuit to drive the motor to rotate. One end of the sampling resistor is connected to the full-bridge circuit, and the other end is grounded. A capacitor C2 is connected in parallel with the sampling resistor.

6. The electric expander with floating expander effective stroke according to claim 1, characterized in that: During the expansion operation, the control chip separately records the pulse signals sent by the non-contact sensor from the start to the present.

7. The electric expander with floating expander effective stroke according to claim 1, characterized in that: The housing includes a right housing that is closed at the right end, and a left housing that covers the left end of the right housing, with the opening located on the left end face of the left housing.

8. The electric expander with floating expander effective stroke according to claim 1, characterized in that: A transmission nut is threaded onto the guide screw, and the transmission nut is located on the right side of the mandrel. A transmission nut seat for abutting the transmission nut is provided on the right inner wall of the housing.

9. The electric expander with floating expander effective stroke according to claim 1, characterized in that: There are two limiting keys, which are symmetrically distributed along the axis of the spindle.

10. The electric expander with floating expander effective stroke according to claim 1, characterized in that: The expanding cone is rotatably connected to the left end of the mandrel via a cone bearing.

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