Pipe expanding tool

Abstract

Provided is an expanding tool. An expanding tool (1) that expands the end portion of a fluid pipe made of synthetic resin is provided with an electric motor (21) housed in a main body case (11). The expanding tool is provided with a screw shaft that is parallel to the output shaft of the electric motor or that is movably disposed in the main body case in the front-rear direction along the axis thereof. The expanding tool is provided with an internally threaded member that is screwed to the screw shaft and moves the screw shaft in the front-rear direction by rotating around the axis of the screw shaft. The expanding tool is provided with a gear (26) that transmits the rotation of the output shaft of the electric motor by engaging with the internally threaded member. The expanding tool is provided with a wedge that extends forward from the screw shaft. The expanding tool is provided with a plurality of jaws (4) that are openably and closably linked to the main body case in such a manner that the jaws are pushed by the wedge and mutually spread apart in the radial direction when the wedge advances together with the screw shaft. Thus, the operability of the expanding tool is improved.

Description

Technical Field

[0001] The present invention relates to a tube expander, for example, for expanding the end of a fluid tube made of synthetic resin in order to connect it to a connected body. Background Technology

[0002] Sometimes, fluid pipes made of PEX (Cross-linked polyethylene) are connected to metal pipes or other connected bodies. In the prior art, a pipe expanding tool is provided to increase the inner diameter of the end of a PEX pipe. The pipe expanding tool is used to increase the diameter of the end of the PEX pipe, thereby installing it onto the connected body. The end of the PEX pipe shrinks in diameter through elastic deformation, gradually returning to its original diameter. The PEX pipe with the reduced diameter is tightly connected to the connected body. The connected PEX pipe is firmly held to the connected body by its own elasticity.

[0003] Patent Document 1 describes a tube expander that uses an electric motor as a drive source to expand the diameter of a PEX tube. The expander has a generally conical wedge at its front, which moves forward or backward relative to the end of the PEX tube, and multiple jaws arranged circumferentially in front of the wedge. The jaws are pushed by the advancing wedge and open radially outward from each other. By opening the jaws radially outward while they are inside the opening at the end of the PEX tube, the end of the PEX tube can be expanded.

[0004] An electric motor and a planetary reduction gear mechanism for slowing down the output of the electric motor are mounted on the main body of the tube expander. A generally cylindrical handle extending downwards from the main body is also provided. The user holds the expander by gripping the handle. In Patent Document 1, the heavy electric motor is positioned in front of the handle. Therefore, the center of gravity of the tool body is closer to the front, reducing the stability of the tool body when gripping the handle. Furthermore, the planetary reduction gear mechanism, with a large diameter and long axial length, is positioned vertically between the handle and the electric motor. This increases the vertical length of the expander, further reducing the stability of the tool body.

[0005] Furthermore, the rate at which PEX tubing shrinks after expansion varies depending on the ambient temperature and the temperature of the PEX tubing itself. For example, at high temperatures, the PEX tubing shrinks elastically and rapidly. Therefore, it is necessary to expand the diameter of the PEX tubing's end to a larger extent. Conversely, at low temperatures, the PEX tubing's plasticity is stronger than its elasticity, resulting in a slower shrinkage rate. Therefore, if the end of the PEX tubing is excessively expanded, it will take time until it is connected to the workpiece. Therefore, it is desirable to reduce the expansion width of the gripper. By moving the wedge forward to the forward end position (front end position), the expansion width of the gripper increases; by moving the wedge backward, the expansion width of the gripper decreases. [Existing Technical Documents] [Patent Literature]

[0006] Patent Document 1: U.S. Patent No. 2020 / 0261959 Summary of the Invention [The technical problem that the invention aims to solve]

[0007] There is room for improvement in tubal reamers so that users can maintain them in a stable state. Therefore, there is a need for a tubal reamer that can maintain a stable state and is easy to operate.

[0008] Furthermore, the drive of the electric motor needs to be controlled by detecting the initial or final position of the wedge movement to move the wedge within that position. However, structures capable of changing and detecting the initial and / or final positions of the wedge have not been practically implemented in existing pipe expanders. Therefore, a pipe expander capable of changing the initial and / or final positions of the wedge is needed. [Technical solutions used to solve technical problems]

[0009] According to one feature of the invention, a pipe expander for expanding the end of a fluid pipe made of synthetic resin has an electric motor housed within a main body housing. The expander has a lead screw shaft disposed within the main body housing parallel to or movable along the axis of the electric motor in a back-and-forth direction. The expander has an internally threaded component that engages with the lead screw shaft and causes the lead screw shaft to move back and forth by rotating about its axis. The expander has a gear that transmits the rotation of the electric motor's output shaft by engaging with the internally threaded component. The expander has a wedge extending forward from the lead screw shaft. The expander has a plurality of jaws, which are closably connected to the main body housing in a manner that allows them to open and close radially outward as the wedge is pushed against it as it advances with the lead screw shaft.

[0010] Therefore, the electric motor is configured with its output shaft extending parallel to the lead screw shaft. This allows the electric motor to extend along the lead screw shaft in the longitudinal direction and be located close to the lead screw shaft. Alternatively, the electric motor can be configured with its output shaft extending coaxially with the lead screw shaft. This places the electric motor near the lead screw shaft. This allows the heavy electric motor to be positioned close to the center of the main housing where the lead screw shaft is located. Therefore, weight balance is good, and the tube expander tool can be held in a stable state. This results in good operability of the tube expander tool. Attached Figure Description

[0011] Figure 1 This is a perspective view of the tube expanding tool involved in the embodiments of the present invention. Figure 2 It is a 3D view showing the tool's main body after its outer shell has been removed. Figure 3 This is a right-side view of the tool after its main body shell has been removed. Figure 4 It is a three-dimensional exploded view of the main body of the tool. Figure 5 This is a longitudinal sectional view of the tube expander with the wedge in its initial position. Figure 6 This is a longitudinal sectional view of the tool body after the gripper has finished rotating. Figure 7 This is a longitudinal sectional view of the tool body with the wedge in the end position. Figure 8 yes Figure 5 Sectional view VIII-VIII in the middle. Figure 9 This is a bottom view of the power conversion ring. Figure 10 This is a diagram of the gripper rotation mechanism viewed from the lower left with the wedge in its initial position. Figure 11 This is a diagram of the gripper rotation mechanism viewed from the lower left, showing the state after the gripper has finished rotating. Figure 12 This is a diagram of the gripper rotation mechanism viewed from the lower left with the wedge in the terminal position. Figure 13 This is a three-dimensional view of the grippers from the rear. Figure 14 This is a block diagram of the electronic components of the tube expander. Figure 15 This is a longitudinal sectional view of the tool body of the tube expanding tool according to the second embodiment, with the wedge in the initial position. Figure 16 Is installation and Figure 15Different multiple grippers and wedges located Figure 15 The longitudinal section view of the tool body in the position shown. Figure 17 This is a longitudinal sectional view of the sensor positioning mechanism. Figure 18 This is a longitudinal sectional view of the sensor positioning mechanism of the tube expanding tool according to the third embodiment. Figure 19 This is a block diagram of the electronic components of the tube expander according to the fourth embodiment. Figure 20 This is a block diagram of the electronic components of the tube expander according to the fifth embodiment. Figure 21 This is a block diagram of the electronic components of the tube expander according to the sixth embodiment. [Explanation of reference numerals in the attached figures] 1: Pipe expanding tool; 2: End cap; 2a: Gripper support groove; 2b: Internal thread; 3: Wedge; 4: Gripper; 4a: Ring receiving groove; 4b: Engaging recess; 4c: Ring; 5: Handle; 6: Switch operating handle; 6a: Switch body; 7: Expanding section; 7a: Battery mounting section; 8: Battery; 10: Tool body; 11: Body housing; 11a: Slot; 12: Front mechanism housing; 12a: External thread; 12b: Engaging part; 12c: Rectangular protrusion; 12d: Rotation limiting part; 12e: Through hole; 13: First central mechanism housing; 13a, 13b: Engaging part; 13c: Boss; 13d: Recess; 13e: Inner circumferential surface; 13f: Through hole; 14: Second central... Central mechanism housing; 14a, 14b: engaging part; 14c: boss part; 14d: recess; 14e: inner circumferential surface; 14f: through hole; 15: rear mechanism housing; 15a: front surface; 15b: engaging part; 15c: boss part; 15d: threaded hole; 16: bolt; 20: motor housing; 21: electric motor; 21a: output shaft; 21b: stator; 21c: rotor; 21d: speed detection sensor; 21e, 21f: bearings; 22: fan; 23: planetary reduction mechanism; 23a: first sun gear; 23b: first internal gear; 23c: first planetary gear; 23d: first planet carrier; 23e: second sun gear; 23f: second internal gear ; 23g: Second planetary gear; 23h: Second planetary carrier; 24: Main spindle; 24a: External thread; 24b, 24c: Main spindle bearings; 25: Feed screw mechanism (ball screw mechanism); 26: Gear; 27: Internal thread component; 27a: Gear; 27b: Internal thread; 27c, 27d: Internal thread component bearings; 27e: Thrust bearing; 27f: Washer; 28: Screw shaft; 28a: External thread; 28b: Ball; 29: Screw shaft guide; 29a: Support component; 29b: Roller; 29c: Guide rail; 30: Gripper rotation mechanism; 31: Linear movement component; 31a: Internal thread; 31b: Protrusion; 31c: Roller; 32: Power conversion ring; 32 a: Groove; 32b: Groove; 32c: Washer; 32d: Through hole; 33: One-way clutch; 34: First rotary drive ring; 34a: Small diameter portion; 34b: Large diameter portion; 34c: Groove; 34d: Through hole; 35: Second rotary drive ring; 35a: Engaging protrusion; 35b: Engaging tooth; 35c: Compression spring; 35d: Spring bearing portion; 35e: Through hole; 36: Third rotary drive ring; 36a: Engaging tooth; 36b: Engaging protrusion; 36c: Through hole; 41: Initial position sensor; 42: Terminal position sensor; 43: Magnet; 44: Position adjustment mechanism; 44a: Operating part; 45: Controller; J: Motor shaft axis; K: Lead screw shaft axis. Detailed Implementation

[0012] According to another feature of the invention, the tube expander has a handle extending downward from the main body housing. The handle is positioned between an electric motor and a plurality of grippers in the front-rear direction. The electric motor is located below a lead screw shaft. Therefore, the electric motor and the plurality of grippers are configured in a way that is well balanced relative to the weight of the handle. This improves the operability of the tube expander when the user holds the handle.

[0013] According to another feature of the invention, at least a portion of the lead screw shaft overlaps with the handle in the longitudinal direction. Therefore, the tube expander tool can be shortened in the longitudinal direction. Consequently, the torque of the tube expander tool about its center of gravity can be reduced, thereby further improving operability.

[0014] According to another feature of the invention, a planetary reduction mechanism for slowing down the output of the output shaft is provided between the output shaft of the electric motor and the lead screw shaft. Therefore, the planetary reduction mechanism can be compactly arranged along the power transmission path from the electric motor to the lead screw shaft. Furthermore, by minimizing the power transmission path from the electric motor to the lead screw shaft, power transmission losses can be suppressed.

[0015] According to another feature of the invention, the pipe expander has a rotary drive ring connected to the rear of a plurality of grippers. The expander has a gripper rotation mechanism that rotates the rotary drive ring via the output of an electric motor, thereby causing the plurality of grippers to rotate circumferentially. The rotary drive ring is positioned in front of the internal threaded component. Therefore, the internal threaded component, the rotary drive ring, and the plurality of grippers are arranged in a front-rear direction extending along the lead screw axis. This allows the center of gravity of the expander to be close to the lead screw axis. Consequently, stability when holding the expander is improved.

[0016] According to another feature of the invention, the pipe expander has an end cap that supports a plurality of jaws in an openable and closable manner and restricts the forward and backward movement of the jaws. The pipe expander has a front mechanism housing, a central mechanism housing, and a rear mechanism housing arranged sequentially from front to rear within a main body housing. The pipe expander has bolts connecting the front and rear mechanism housings. The front mechanism housing is made of iron and serves to support the end cap. The rear mechanism housing is made of iron and serves to support the rear end of the internally threaded component. The central mechanism housing is formed of a material lighter than iron.

[0017] Therefore, the structure is divided into a front mechanism housing, a central mechanism housing, and a rear mechanism housing along the front-to-back direction. The front mechanism housing, including the end cap and support end cap, is forcefully pushed forward by the multiple jaws when they open. The internal thread component is forcefully pushed backward by the reaction force that moves the lead screw axially forward. For example, in the case where the front, central, and rear mechanism housings are integrated into a single component, strong tensile forces are generated at the front and rear ends along the front-to-back direction when the jaws expand. Therefore, the overall mechanism housing needs to be designed with high strength. The front, central, and rear mechanism housings are divided along the front-to-back direction, and the front and rear mechanism housings are made of iron. This allows the tensile forces along the front-to-back direction to be distributed separately in the high-strength front and rear mechanism housings. Furthermore, by using a lightweight material for the central mechanism housing, the tube expanding tool can be made lighter.

[0018] According to another feature of the invention, the tube expanding tool has a second central mechanism housing between the central mechanism housing and the rear mechanism housing. The front mechanism housing, central mechanism housing, second central mechanism housing, and rear mechanism housing each have an engagement portion at each end that overlaps with each other in the longitudinal direction for abutment. Therefore, by making the engagement portions overlap in the longitudinal direction, the front mechanism housing and the central mechanism housing can be positioned relative to each other with high precision. Furthermore, the engagement portions between the central mechanism housing and the second central mechanism housing, and between the second central mechanism housing and the rear mechanism housing, can also be positioned with high precision. Therefore, the assembly of each mechanism housing is good, and the wobbling of internally threaded components and the like housed inside can be suppressed.

[0019] According to another feature of the invention, a main shaft that rotates integrally with the gear is provided in front of the output shaft. The central mechanism housing and the second central mechanism housing support the main shaft bearing, which rotatably supports the main shaft, and the internal thread component bearing, which rotatably supports the internal thread component. Therefore, the main shaft bearing and the internal thread component bearing are subjected to almost no force in the front-to-back direction. Thus, the main shaft and the internal thread component can be adequately supported by the central mechanism housing and the second central mechanism housing, which have lower strength than the front and rear mechanism housings. This reduces the need for iron-made parts, thereby enabling a lighter tube expanding tool.

[0020] According to another feature of the invention, the rear mechanism housing supports a thrust bearing that abuts against the rear end of the internal threaded component. Therefore, the internal threaded component is forcefully pushed rearward as the lead screw moves forward. The rear mechanism housing can withstand the force of the rearward push on the internal threaded component via the thrust bearing. Therefore, the internal threaded component can rotate with high precision about the axis of the lead screw. Consequently, the lead screw can move with high precision in the front-rear direction.

[0021] According to another feature of the invention, balls are clamped in the engagement portion between the lead screw shaft and the internal threaded component. Therefore, the transmission efficiency of the driving force is improved by the balls clamped in the engagement portion. Thus, the rotational drive of the internal threaded component relative to the lead screw shaft can be efficiently converted into the forward and backward movement of the lead screw shaft.

[0022] According to another feature of the invention, a pipe expander for expanding the end of a fluid pipe made of synthetic resin has a controller that switches the output shaft of an electric motor to forward and reverse rotation. The lead screw moves back and forth between an initial rear position and a final forward position via rotation of an internal threaded component. The expander has an initial position sensor or a final position sensor, or both, that sends a signal to the controller by detecting the lead screw at its initial or final position. The initial position sensor and / or the final position sensor are configured to move in the back-and-forth direction. The initial position and / or the final position of the lead screw can be varied based on the position of the initial position sensor and / or the final position sensor.

[0023] Therefore, by moving the end position sensor forward, the end position of the wedge moving forward can be set further forward. Consequently, the force with which the wedge pushes the multiple grippers radially outward at the end position increases. This allows for an increase in the radially outward expansion width of the multiple grippers. Therefore, for example, in cases of high temperature and rapid fluid tube contraction, the end of the fluid tube can be expanded to a larger diameter. Conversely, by moving the end position sensor backward, the end position of the wedge moving forward can be set further backward. Consequently, the force with which the wedge pushes the multiple grippers radially outward at the end position decreases. This allows for a decrease in the radially outward expansion width of the multiple grippers. Therefore, for example, in cases of low temperature and slow fluid tube contraction, the end of the fluid tube can be expanded to a smaller diameter. Thus, the expansion width of the grippers can be varied according to the air temperature, the fluid tube temperature, etc.

[0024] By moving the initial position sensor forward, the initial position of the wedge can be set further forward. Therefore, the time it takes for the wedge to move from its initial position to abut against the grippers can be shortened. This, in turn, shortens the time of one cycle of opening and closing the grippers, thereby reducing operation time. By moving the initial position sensor backward, the initial position of the wedge can be set further backward. Therefore, for example, when using grippers with radially thick walls, the initial position of the wedge can be moved backward without interference between the wedge at its initial position and the grippers.

[0025] According to another feature of the invention, the initial position sensor and / or the final position sensor have a Hall effect IC disposed within the main housing. A magnet is disposed on the lead screw. Therefore, the structure for detecting the initial position and / or final position of the lead screw can be made simple and compact. Therefore, the main housing including the initial position sensor and the final position sensor can be made compact.

[0026] According to another feature of the invention, the initial position sensor and / or the terminal position sensor have an operating portion protruding outward from the main housing. Therefore, the user can move the initial position sensor and / or the terminal position sensor by operating the operating portion from outside the main housing. Thus, the initial position sensor and / or the terminal position sensor can be easily moved to the target position.

[0027] According to another feature of the invention, the tube expander has a handle extending downward from the main body housing. The operating part protrudes from the upper surface of the main body housing. Therefore, the operating part is positioned above the main body housing, allowing the user to operate it while visually observing it. This ensures good operability of the operating part.

[0028] According to another feature of the invention, the pipe expander has a jaw rotation mechanism that rotates multiple jaws circumferentially via the output of an electric motor. A controller can supply current to the electric motor according to a first upper limit value and a second upper limit value, wherein the first upper limit value is the current flowing in the electric motor during the rotation of the multiple jaws; and the second upper limit value is the current flowing in the electric motor during the expansion section where the multiple jaws open radially outward. Therefore, the upper limit value of the current flowing in the electric motor can be changed between the rotation section and the expansion section. Thus, for example, it is possible to suppress the continuous operation of the electric motor when the jaws cannot rotate. Consequently, excessive load applied to the jaws, wedges, and jaw rotation mechanism can be suppressed.

[0029] According to another feature of the invention, the tube expander has a speed detection sensor that sends a signal to a controller by detecting the rotational speed of an electric motor. The controller sets the rotational range and the expansion range based on the signal sent by the speed detection sensor and a detection signal indicating that the lead screw has moved to an initial or final position. Therefore, when the final position of the wedge is changed by moving the final position sensor, the rotational range and the expansion range can be reset. Thus, the rotational and expansion actions of the grippers can be appropriately controlled so that the fluid tube can be expanded with an expansion width corresponding to the contraction speed of the fluid tube.

[0030] According to another feature of the invention, the first upper limit value is set lower than the second upper limit value. Therefore, the upper limit value of the current flowing in the electric motor during the rotational range when the load applied to the gripper and the gripper rotation mechanism is small is reduced. Thus, over-driving of the electric motor during the rotational range can be suppressed. Consequently, the load applied to the gripper and the gripper rotation mechanism can be minimized.

[0031] According to another feature of the invention, the rotational section is the section where the wedge advances and precedes the diameter expansion section. Therefore, the multiple grippers expand radially after rotating circumferentially along the wedge. By clearly distinguishing the rotational and diameter expansion actions of the multiple grippers, unintentional loads applied to the grippers and the gripper rotation mechanism can be suppressed.

[0032] According to another feature of the invention, the rotation interval is the wedge retraction interval and follows the diameter expansion interval. Therefore, after the multiple grippers close together radially inward, they rotate circumferentially along the wedge. In this case, since the rotational and diameter expansion actions of the multiple grippers are clearly distinguished, unintentional loads applied to the grippers and the gripper rotation mechanism can be suppressed.

[0033] According to another feature of the invention, balls are clamped in the engagement portion between the lead screw shaft and the internal threaded component. Therefore, the transmission efficiency of the driving force is improved by the balls clamped in the engagement portion. Thus, the rotational drive of the internal threaded component relative to the lead screw shaft can be efficiently converted into the forward and backward movement of the lead screw shaft.

[0034] According to another feature of the invention, the pipe expander is capable of replacing the multiple jaws by installing multiple second jaws with different wall thicknesses radially different from the multiple jaws. Therefore, it is possible to expand the diameter of various fluid pipes with different diameters using a single pipe expander.

[0035] According to another feature of the invention, the pipe expander tool has a sensor positioning mechanism capable of releasably positioning an initial position sensor and / or an end position sensor at multiple positions in the longitudinal direction. Therefore, the initial position sensor can be positioned at a preferred plurality of positions that serve as the initial position of the wedge. Alternatively, the end position sensor can be positioned at a preferred plurality of positions that serve as the end position of the wedge. Thus, the user does not need to perform fine-tuning of the initial and / or end positions, thereby improving usability. Furthermore, unintentional movement of the positioned initial and / or end position sensors can be suppressed.

[0036] Next, according to Figures 1 to 14 To illustrate one embodiment of the present invention. For example... Figure 1 As shown, the tube expander 1 of this embodiment has a tool body 10 housed in a generally cylindrical body shell 11 and a handle 5 extending downward from the center of the tool body 10 in a front-rear direction. The user is positioned approximately behind the tube expander 1. Figure 1 Hold the handle 5 from the left (deep side) of the handlebars. In the following description, the side closest to the user is designated as the rear, and the side opposite to the user's front is designated as the front. The up, down, left, and right directions are based on the user.

[0037] like Figure 1 , 4 As shown, an annular end cap 2 is mounted on the front part of the main body shell 11, which is located forward of the grip 5. A generally conical wedge 3 extending in the front-rear direction is provided on the inner side of the inner circumferential surface of the end cap 2. The wedge 3 is mounted on the front end of a cylindrical lead screw shaft 28 extending in the front-rear direction at the center of the main body shell 11. The wedge 3 can move along the lead screw shaft 28 in the front-rear direction. Multiple grippers 4 extending in the front-rear direction are provided radially outward of the wedge 3 and radially inward of the end cap 2. The multiple grippers 4 are arranged at equal intervals along the circumference of the wedge 3. For example, six grippers 4 are provided, each gripper 4 arranged at 60° intervals along the circumference of the wedge 3. The multiple grippers 4 can open and close radially between a closed position where they are tightly covered by each other circumferentially and an open position where they are radially open, exposing the tips of the wedge 3.

[0038] like Figure 1 As shown, a trigger-type switch lever 6 is provided on the front surface of the grip 5. The user can operate the switch lever 6 while holding the grip 5. A switch body 6a is provided inside the grip 5, which switches on and off in a manner linked to the operation of the switch lever 6. When the switch lever 6 is not pulled, the switch body 6a is in the off state; when the switch lever 6 is pulled, the switch body 6a is in the on state. At the lower end of the grip 5, there is a generally rectangular box-shaped expansion section 7 that expands in diameter relative to the grip 5 in the front-back direction and the left-right direction. A controller 45 is housed in the expansion section 7. The controller 45 has a shallow rectangular box-shaped housing and a control base plate molded from resin and housed within the housing. The controller 45 is housed in the expansion section 7 in a vertical orientation along the thickness direction (the direction in which the shortest side of the housing extends). The controller 45 mainly controls the drive of the electric motor 21, which will be described later.

[0039] like Figure 1 As shown, a battery mounting portion 7a is provided on the lower surface of the expanded diameter portion 7, allowing for the detachable mounting of a rectangular box-shaped battery 8. The battery 8 can be removed from the battery mounting portion 7a by sliding forward relative to it. The battery 8 can also be mounted on the battery mounting portion 7a by sliding backward from its front end. The battery 8 can be repeatedly charged and used using a separately provided charger after being removed from the battery mounting portion 7a. The battery 8 can be used as a power source for other power tools. The battery 8 functions as a power source supplying electrical power to the electric motor 21.

[0040] like Figure 4 As shown, the main body housing 11 sequentially houses, from front to rear, a front mechanism housing 12, a first central mechanism housing 13, a second central mechanism housing 14, and a rear mechanism housing 15. The front mechanism housing 12, the first central mechanism housing 13, and the second central mechanism housing 14 are generally cylindrical in shape, each having a through hole extending in the front-to-back direction at the center. The rear mechanism housing 15 is plate-shaped with its thickness along the front-to-back direction. The front mechanism housing 12, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 work together to form a mechanism housing for housing the main shaft 24 and the internal threaded component 27, described later. The front mechanism housing 12 and the rear mechanism housing 15 are made of iron. The first central mechanism housing 13 and the second central mechanism housing 14 are made of aluminum.

[0041] like Figure 2 , 4 As shown, an external thread 12a is provided on the outer peripheral surface of the front part of the front mechanism housing 12. An internal thread 2b is provided on the inner peripheral surface of the end cap 2, which engages with the external thread 12a. By engaging the external thread 12a with the internal thread 2b, the end cap 2 is connected to the front part of the front mechanism housing 12. A generally rectangular, plate-shaped rectangular protrusion 12c, extending radially outward, is provided on the rear part of the front mechanism housing 12. Through holes 12e, extending in the front-rear direction, are formed at the four corners of the rectangular protrusion 12c.

[0042] like Figure 2 , 4 As shown, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 each have four radially outwardly extending bosses 13c, 14c, and 15c. Each boss 13c, 14c, and 15c is formed into a generally cylindrical shape extending in the front-rear direction. A through hole 13f or 14f extending in the front-rear direction is provided in the center of each boss 13c and 14c. A threaded hole 15d extending in the front-rear direction is provided in the center of each boss 15c.

[0043] like Figure 2 , 4 As shown, rectangular protrusions 12c and bosses 13c, 14c, and 15c are arranged along the front-to-back direction, and through holes 12e, 13f, and 14f are connected to threaded holes 15d in the front-to-back direction. Four bolts 16 are inserted from the front to the rear into the connected through holes 12e, 13f, and 14f, and are tightened into the threaded holes 15d. Thus, the front mechanism housing 12 and the rear mechanism housing 15 are connected by bolts 16 in a state in which the first central mechanism housing 13 and the second central mechanism housing 14 are sandwiched in the middle in the front-to-back direction.

[0044] like Figures 3-5As shown, a generally cylindrical engaging portion 12b and an engaging portion 13a are respectively provided at the rear end of the front housing 12 and the front end of the first central housing 13. The inner circumferential surface of the engaging portion 12b and the outer circumferential surface of the engaging portion 13a have approximately the same diameter. The engaging portions 12b and 13a overlap in the front-rear direction and engage through a so-called embedded structure where the inner circumferential surface of the engaging portion 12b is in close contact with the outer circumferential surface of the engaging portion 13a.

[0045] like Figures 3-5 As shown, a generally cylindrical engaging portion 13b and an engaging portion 14a are respectively provided at the rear end of the first central mechanism housing 13 and the front end of the second central mechanism housing 14. The inner circumferential surface of the engaging portion 13b and the outer circumferential surface of the engaging portion 14a have approximately the same diameter. The engaging portions 13b and 14a overlap in the front-rear direction and are engaged by an embedded structure in which the inner circumferential surface of the engaging portion 13b is in close contact with the outer circumferential surface of the engaging portion 14a.

[0046] like Figures 3-5 As shown, a generally cylindrical engaging portion 14b is provided at the rear end of the second central housing 14. A generally cylindrical engaging portion 15b protruding forward is provided on the front surface of the rear housing 15. The inner and outer circumferential surfaces of the engaging portion 14b and the engaging portion 15b have approximately the same diameter. The engaging portions 14b and 15b overlap in the front-rear direction and engage through an embedded structure in which the inner circumferential surface of the engaging portion 14b is in close contact with the outer circumferential surface of the engaging portion 15b.

[0047] like Figure 1 , 5 As shown, a generally cylindrical motor housing 20 for housing the electric motor 21 is provided at the rear of the main body housing 11. The motor housing 20 is located below the lead screw shaft 28 and above and behind the handle 5. The electric motor 21 is, for example, a motor referred to as a DC brushless motor. The output shaft 21a of the electric motor 21 extends along the motor axis J in a front-rear direction parallel to the lead screw shaft 28. The output shaft 21a is supported by bearings 21e and 21f mounted on the motor housing 20 so that it can rotate about the motor axis J.

[0048] like Figure 5As shown, the stator 21b of the electric motor 21 is supported on the inner circumferential surface of the motor housing 20 in a non-rotatable manner. The rotor 21c of the electric motor 21 is mounted on the output shaft 21a on the inner circumferential side of the stator 21b in a manner that allows it to rotate integrally with the output shaft 21a. A speed detection sensor 21d is provided in front of the rotor 21c. The speed detection sensor 21d detects the speed of the output shaft 21a by detecting the rotation angle of the rotor 21c. In the front-rear direction, a fan 22 for introducing cooling air into the motor housing 20 is integrally mounted with the output shaft 21a between the rotor 21c and the rear bearing 21f. When the fan 22 rotates together with the output shaft 21a, the cooling air flows from the front to the rear of the motor housing 20.

[0049] like Figure 5 As shown, a planetary reduction gear 23 for reducing the output of the output shaft 21a is provided in front of the electric motor 21. The planetary reduction gear 23 is approximately cylindrical with the motor axis J as its center and a diameter approximately the same as that of the electric motor 21. At the rear end of the planetary reduction gear 23, a first sun gear 23a is integrally provided with the front end of the output shaft 21a. A first internal gear 23b, which is annular and centered on the motor axis J, is provided radially outward of the first sun gear 23a. A plurality of first planetary gears 23c mesh between the first sun gear 23a and the first internal gear 23b. The first planetary gears 23c are connected to a first planet carrier 23d in front of the first sun gear 23a. The rotational drive of the output shaft 21a is transmitted to the first planet carrier 23d in a reduced speed via the first sun gear 23a and the first planetary gears 23c.

[0050] like Figure 5 As shown, the first planetary carrier 23d is integrally mounted with the second sun gear 23e and can rotate together with the second sun gear 23e around the motor axis J. A ring-shaped second internal gear 23f, centered on the motor axis J, is disposed radially outward of the second sun gear 23e. Multiple second planetary gears 23g mesh between the second sun gear 23e and the second internal gear 23f. The second planetary gears 23g are connected to the second planetary carrier 23h, which is positioned in front of the second sun gear 23e. The second planetary carrier 23h is integrally mounted with the main shaft 24 and can rotate around the motor axis J. Therefore, the rotational drive of the first planetary carrier 23d is transmitted to the main shaft 24 at a reduced speed via the second sun gear 23e, the second planetary gears 23g, and the second planetary carrier 23h. Thus, the rotational drive of the output shaft 21a is transmitted to the main shaft 24 at a reduced speed via the planetary reduction mechanism 23.

[0051] like Figure 5As shown, the main shaft 24 is supported by main shaft bearings 24b and 24c, enabling it to rotate about the motor axis J. The front main shaft bearing 24b is pressed into a recess 13d in the lower part of the first central mechanism housing 13. The rear main shaft bearing 24c is pressed into a recess 14d in the lower part of the second central mechanism housing 14. The main shaft bearings 24b and 24c are housed within a space formed by the cooperative operation of the first central mechanism housing 13 and the second central mechanism housing 14. A gear 26 for transmitting power to the lead screw shaft 28 is integrally rotatably mounted on the main shaft 24. The gear 26 is positioned between the front and rear of the main shaft bearings 24b and 24c. An external thread 24a is formed on the outer circumferential surface of the main shaft 24, in front of the main shaft bearing 24b.

[0052] like Figure 4 , 5 As shown, a feed screw mechanism 25, referred to as a ball screw mechanism, is provided on the tool body 10. The feed screw mechanism 25 has a screw shaft 28, an internal thread component 27, and a gear 26. The screw shaft 28 is arranged on a screw shaft axis K located at the center of the main body housing 11 and extending in the front-rear direction. The screw shaft 28 is movable in the front-rear direction along the screw shaft axis K. At any position from the rear end to the front end of the movement range, at least a portion of the screw shaft 28 overlaps with the handle 5 in the front-rear direction. When the screw shaft 28 is located at the rearmost end of the movement range, it overlaps with the output shaft 21a in the front-rear direction. The internal thread component 27 is formed into a generally cylindrical shape that screws into the screw shaft 28 and meshes with the gear 26. An internal thread 27b is provided on the inner circumferential surface of the internal thread component 27. The internal thread 27b engages with the external thread 28a of the screw shaft 28 via a plurality of balls 28b. A gear 27a is provided at the center of the internal threaded component 27 in the front-rear direction, protruding radially outward and meshing with the gear 26. Through the meshing of the gear 27a and the gear 26, the rotational drive of the main shaft 24 is transmitted to the internal threaded component 27 in a decelerated manner.

[0053] like Figure 4 , 5As shown, the internal threaded component 27 is supported by front and rear internal threaded component bearings 27c and 27d, enabling it to rotate about the lead screw axis K. The internal threaded component bearing 27c in front of the gear 27a is pressed into the inner circumferential surface 13e of the first central mechanism housing 13. The internal threaded component bearing 27d behind the gear 27a is pressed into the inner circumferential surface 14e of the second central mechanism housing 14. The internal threaded component bearings 27c and 27d are housed within the space formed by the cooperative operation of the first central mechanism housing 13 and the second central mechanism housing 14. A thrust bearing 27e is provided between the rear surface of the internal threaded component 27 and the front surface 15a of the rear mechanism housing 15 to withstand the thrust load that pushes the internal threaded component 27 backward. A washer 27f is provided between the front surface of the internal threaded component 27 and the rear surface of the power conversion ring 32 (described later).

[0054] like Figure 2 , 3 As shown, a lead screw guide 29 is provided at the rear of the lead screw shaft 28 to guide the lead screw shaft 28 to move back and forth relative to the main housing 11. The lead screw guide 29 has a support member 29a connected to the lead screw shaft 28 and extending in the left-right direction, and rollers 29b provided at the left and right ends of the support member 29a. A pair of annular guide rails 29c extending in the front-back direction are provided on the left and right inner circumferential surfaces of the main housing 11. The rollers 29b can engage with the guide rails 29c and move along the guide rails 29c in the front-back direction. The lead screw shaft 28 can be guided by the rollers 29b to move in the front-back direction.

[0055] like Figure 4 , 5 As shown, a gripper rotation mechanism 30 for rotating multiple grippers 4 is provided on the tool body 10. The gripper rotation mechanism 30 has a linear motion member 31 and a power conversion ring 32. The linear motion member 31 is formed into a generally cylindrical shape with the front-to-back direction as the axial direction. The linear motion member 31 has an internal thread 31a provided on its inner circumferential surface and a cylindrical protrusion 31b extending orthogonally to the axial direction of the generally cylindrical shape. A roller 31c is provided at the upper end of the protrusion 31b, which covers the protrusion 31b circumferentially and is rotatable about the axis of the protrusion 31b. The internal thread 31a of the linear motion member 31 engages with the external thread 24a of the spindle 24. A rotation limiting part 12d for limiting the rotation of the linear motion member 31 is provided at the lower part of the front mechanism housing 12. The rotation limiting part 12d is formed into a groove shape that penetrates the front mechanism housing 12 radially and extends linearly in the front-to-back direction.

[0056] like Figure 4 , 9As shown, the power conversion ring 32 is generally cylindrical in shape with a through hole 32d extending through the center in the front-to-back direction. Grooves 32a and 32b are recessed on the lower outer circumferential surface of the power conversion ring 32. Groove 32a extends circumferentially along the power conversion ring 32, for example, in a direction intersecting the axial direction (front-to-back direction) of the power conversion ring 32 at a 45° angle. Viewed from the front, the inclination direction of groove 32a is counterclockwise towards the front. Groove 32b extends parallel to the axial direction of the power conversion ring 32. A protrusion 31b, on which a roller 31c is mounted, is inserted into grooves 32a and 32b. The front end of groove 32a communicates with the rear end of groove 32b to allow the protrusion 31b to move smoothly.

[0057] like Figures 5-8 As shown, the power conversion ring 32 is housed in the front mechanism housing 12. The linear motion member 31 engages with the external thread 24a of the main shaft 24 below the front mechanism housing 12. A protrusion 31b extends upward through the rotation limiting portion 12d and is inserted into the groove 32a or 32b. A roller 31c abuts against both the walls of the grooves 32a and 32b and the wall of the rotation limiting portion 12d. The rotation of the main shaft 24 about its axis is limited by the engagement of the protrusion 31b of the linear motion member 31 with the rotation limiting portion 12d.

[0058] like Figures 10-12 As shown, when the spindle 24 rotates around its axis, the linear motion component 31 moves in the front-to-back direction due to the engagement of the external thread 24a and the internal thread 31a, and the restriction of the rotation of the linear motion component 31 around its axis. When the linear motion component 31 is at the rear end of its movement range, the protrusion 31b is located at the rear end of the groove 32a. When the linear motion component 31 moves forward from its rear end, the protrusion 31b moves forward within the groove 32a. Because the rotation of the linear motion component 31 is restricted, the protrusion 31b does not move in the left-to-right direction. Therefore, the advancing protrusion 31b pushes against the wall of the groove 32a. Thus, viewed from the front, the power conversion ring 32 rotates clockwise around the screw axis K. When the linear motion component 31 moves further forward, the protrusion 31b enters the groove 32b from the groove 32a. The groove 32b is not tilted relative to the front-to-back direction, so no force is generated whereby the protrusion 31b pushes against the wall of the groove 32b. Therefore, the power conversion ring 32 does not rotate.

[0059] like Figures 10-12 As shown, when the linear moving part 31 moves backward from the front end of the moving range, the protrusion 31b first moves within the groove 32b. At this time, since no force is generated whereby the protrusion 31b pushes against the wall of the groove 32b, the power conversion ring 32 does not rotate. When the protrusion 31b moves backward within the groove 32a, the protrusion 31b pushes against the wall of the groove 32a, and thus, viewed from the front, the power conversion ring 32 rotates counterclockwise.

[0060] like Figure 4 , 5 As shown, a cylindrical one-way clutch 33 and a generally cylindrical first rotary drive ring 34 are disposed radially inward of the power conversion ring 32. The one-way clutch 33 is mounted on the inner circumferential surface of the power conversion ring 32. The first rotary drive ring 34 is disposed radially inward of the one-way clutch 33 and radially outward of the lead screw shaft 28. The one-way clutch 33 only allows clockwise rotational drive when viewed from the front and transmits it from the power conversion ring 32 to the first rotary drive ring 34. On the other hand, counterclockwise rotational drive when viewed from the front is not transmitted from the power conversion ring 32 to the first rotary drive ring 34 via the one-way clutch 33.

[0061] like Figure 4 , 5 As shown, the first rotary drive ring 34 is generally cylindrical in shape with a through hole 34d extending through the center in the front-rear direction. The lead screw shaft 28 is inserted into the through hole 34d in a manner movable in the front-rear direction. The first rotary drive ring 34 has a small-diameter portion 34a and a large-diameter portion 34b, both cylindrical in shape and centered on the lead screw shaft axis K. The small-diameter portion 34a is positioned behind the large-diameter portion 34b. The small-diameter portion 34a is pressed into the inner circumferential surface of the one-way clutch 33. A plurality of grooves 34c extending in the front-rear direction are recessed on the outer circumferential surface of the large-diameter portion 34b. The plurality of grooves 34c are arranged at predetermined intervals in the circumferential direction, for example, at 90° intervals in the circumferential direction of the large-diameter portion 34b.

[0062] like Figure 4 , 5 As shown, a second rotary drive ring 35 is provided in front of the first rotary drive ring 34 and engages with the first rotary drive ring 34. The second rotary drive ring 35 is generally cylindrical in shape with a through hole 35e extending through the center in the front-rear direction. The lead screw shaft 28 and the first rotary drive ring 34 are inserted into the through hole 35e. A plurality of engaging protrusions 35a protruding radially inward are provided on the inner circumferential surface of the second rotary drive ring 35. By inserting the first rotary drive ring 34 into the through hole 35e, the plurality of engaging protrusions 35a engage with a plurality of grooves 34c. Therefore, the second rotary drive ring 35 can rotate integrally with the first rotary drive ring 34 about the lead screw shaft axis K, and can slide relative to the first rotary drive ring 34 in the front-rear direction.

[0063] like Figure 4 , 5As shown, a spring receiving portion 35d extending radially outward is provided at the front of the outer peripheral surface of the second rotary drive ring 35. A washer 32c is provided in front of the front surface of the power conversion ring 32. A compression spring 35c is clamped between the spring receiving portion 35d and the washer 32c. The second rotary drive ring 35 is subjected to forward force by the compression spring 35c. A plurality of meshing teeth 35b with a convex-concave shape that repeats in the circumferential direction are provided on the front surface of the second rotary drive ring 35.

[0064] like Figure 4 , 5 As shown, a third rotary drive ring 36 is provided in front of the second rotary drive ring 35, engaging with the second rotary drive ring 35 and multiple grippers 4. The third rotary drive ring 36 is generally cylindrical in shape with a through hole 36c extending through the center in the front-rear direction. The lead screw shaft 28 is inserted into the through hole 36c. Multiple meshing teeth 36a with a circumferentially repeating front-rear convex-concave shape are provided on the rear surface of the third rotary drive ring 36. The meshing teeth 36a engage with the meshing teeth 35b of the second rotary drive ring 35. The third rotary drive ring 36 can rotate integrally with the second rotary drive ring 35 around the lead screw shaft axis K by the engagement of the meshing teeth 35b and the meshing teeth 36a. Multiple engaging protrusions 36b protruding forward are provided on the front end face of the third rotary drive ring 36. Each engaging protrusion 36b engages with an engaging recess 4b provided on the rear end face of the gripper 4 (see reference). Figure 13 The multiple grippers 4 are engaged. As a result, the multiple grippers 4 can rotate integrally with the third rotary drive ring 36 around the lead screw axis K.

[0065] Sometimes, for example, the gripper 4 may bite the inner circumferential surface of the fluid pipe. In this case, the second rotary drive ring 35 retracts against the force of the compression spring 35c and disengages from the third rotary drive ring 36. As a result, the engagement of the meshing teeth 35b and 36a is disengaged. Therefore, the power transmission path for rotating the multiple grippers 4 around the lead screw axis K is cut off between the second rotary drive ring 35 and the third rotary drive ring 36. As a result, the overload of the rotary drive on the grippers 4 that are biting the fluid pipe can be suppressed, thereby preventing damage to individual components (e.g., the linear motion component 31 for transmitting power, the power conversion ring 32, and the rotary drive rings 34, 35, and 36).

[0066] like Figures 5-7As shown, an annular receiving groove 4a with an arc-shaped cross-section is provided on the radially outer periphery of the rear part of the gripper 4. The annular receiving grooves 4a of multiple grippers 4 are connected in the circumferential direction to form an annular groove. Multiple grippers 4 are connected in the circumferential direction by rings 4c that are inserted into the annular receiving grooves 4a and are elastically expandable. A gripper support groove 2a for receiving rings 4c is provided on the inner circumferential surface of the end cap 2 in a radially outward and circumferential manner. The gripper support groove 2a allows radial movement of rings 4c, but restricts the forward and backward movement of rings 4c. Multiple grippers 4 open and close radially with respect to the rings 4c supported by the gripper support grooves 2a.

[0067] like Figures 5-7 As shown, multiple grippers 4 open radially outward as the wedge 3 advances, pushing the end cap 2 forward and radially outward. The front mechanism housing 12, integral with the end cap 2, experiences a strong forward tensile force as the wedge 3 advances. The internal thread component 27 is pushed backward by the reaction force as the lead screw 28, integral with the wedge 3, advances. The rear mechanism housing 15 receives the force of the internal thread component 27 pushing backward via the thrust bearing 27e. Therefore, as the wedge 3 and the lead screw 28 advance, a strong tensile force separating the front mechanism housing 12 and the rear mechanism housing 15 in the front-rear direction is generated.

[0068] like Figures 5-7 As shown, a first central mechanism housing 13 and a second central mechanism housing 14, which can be separated in the front-rear direction, are sandwiched between the front mechanism housing 12 and the rear mechanism housing 15. Therefore, the forward force on the front mechanism housing 12 is not transmitted to the rear mechanism housing 15. Similarly, the rearward force on the rear mechanism housing 15 is not transmitted to the front mechanism housing 12. Furthermore, both the front mechanism housing 12 and the rear mechanism housing 15 are made of iron. Therefore, the front mechanism housing 12 and the rear mechanism housing 15 have the rigidity to withstand tensile forces that separate them in the front-rear direction.

[0069] like Figures 5-7As shown, the first central mechanism housing 13 houses and supports the main shaft bearing 24b and the internal thread component bearing 27c. The second central mechanism housing 14 houses and supports the main shaft bearing 24c and the internal thread component bearing 27d. Although the main shaft 24, supported rotatably by the main shaft bearings 24b and 24c, experiences a reaction force from the forward and backward movement of the linear motion member 31, this force is sufficiently small compared to the reaction force experienced by the internal thread component 27. Therefore, the main shaft bearings 24b and 24c experience almost no force in the forward and backward direction. The internal thread component 27, supported rotatably by the internal thread component bearings 27c and 27d, receives a rearward pushing force from the thrust bearing 27e. Therefore, the internal thread component bearings 27c and 27d experience almost no force in the forward and backward direction. Furthermore, the first central mechanism housing 13 and the second central mechanism housing 14 can be separated in the forward and backward direction relative to the front mechanism housing 12 and the rear mechanism housing 15. Thus, when the tube expanding tool 1 is in operation, the first central mechanism housing 13 and the second central mechanism housing 14 are subjected to almost no force in the front-to-back direction. Therefore, the first central mechanism housing 13 and the second central mechanism housing 14 can be made of lightweight cast aluminum.

[0070] Reference Figures 5-7 10~ Figure 12 The driving mechanism of the feed screw mechanism 25 and the gripper rotation mechanism 30 will be explained below. First, the output shaft 21a of the electric motor 21 rotates. The rotation drive of the output shaft 21a is reduced by the planetary reduction mechanism 23 and then transmitted to the main shaft 24. When the main shaft 24 rotates, the internal thread component 27 rotates through the meshing of gear 26 and gear 27a. In addition, the linear motion component 31 moves in the front-back direction due to the engagement of the external thread 24a and the internal thread 31a and the restriction of the rotation of the linear motion component 31 implemented by the rotation restriction part 12d. When the internal thread component 27 rotates, the screw shaft 28 moves in the front-back direction through the engagement of the internal thread 27b and the external thread 28a. When the screw shaft 28 moves forward, the wedge 3 installed at the front end of the screw shaft 28 pushes the multiple grippers 4 and rings 4c to a radially outward open position. As the lead screw 28 retracts, the pushing force of the wedge 3 is eliminated, causing the ring 4c to contract and the multiple grippers 4 to return to the radially inward closed position.

[0071] When the linear motion component 31 advances and the protrusion 31b advances within the groove 32a, the power conversion ring 32 rotates clockwise when viewed from the front. The rotational drive of the power conversion ring 32 is transmitted to the first rotary drive ring 34 via a one-way clutch 33. The first rotary drive ring 34, the second rotary drive ring 35, and the third rotary drive ring 36 rotate clockwise when viewed from the front. Therefore, the plurality of grippers 4 supported by the third rotary drive ring 36 also rotate clockwise when viewed from the front. When the protrusion 31b advances within the groove 32b, the power conversion ring 32 does not rotate. Therefore, the first rotary drive ring 34, the second rotary drive ring 35, the third rotary drive ring 36, and the plurality of grippers 4 do not rotate.

[0072] When the linear motion component 31 retracts and the protrusion 31b retracts within the groove 32b, the power conversion ring 32 does not rotate. Therefore, the first rotary drive ring 34, the second rotary drive ring 35, the third rotary drive ring 36, and the plurality of grippers 4 do not rotate. When the protrusion 31b retracts within the groove 32a, the power conversion ring 32 rotates counterclockwise when viewed from the front. The one-way clutch 33 only transmits rotational drive in the clockwise direction when viewed from the front to the first rotary drive ring 34. Therefore, the first rotary drive ring 34, the second rotary drive ring 35, the third rotary drive ring 36, and the plurality of grippers 4 do not rotate.

[0073] Electric motor 21 is controlled by controller 45 (see reference). Figure 1 The motor 21 is switched between forward and reverse rotation. Multiple grippers 4 are pushed radially outward by the advancing wedge 3 when the motor 21 rotates forward. Additionally, when the motor 21 rotates forward, the multiple grippers 4 rotate clockwise when viewed from the front via the gripper rotation mechanism 30. When the motor 21 rotates in reverse, the multiple grippers 4 close radially inward as the wedge 3 retracts. Furthermore, when the motor 21 rotates in reverse, the multiple grippers 4 are prevented from rotating by the rotation restriction of the one-way clutch 33.

[0074] The timing of the rotation of the multiple grippers 4, achieved by the gripper rotation mechanism 30, and the opening and closing of the multiple grippers 4, achieved by the back-and-forth movement of the wedge 3 via the feed screw mechanism 25, can be modified through the design of each mechanism. For example, the timing of the actions can be changed by altering the shape of the slots 32a and 32b provided in the power conversion ring 32, or the range of movement of the screw shaft 28 in the back-and-forth direction. In this embodiment, the multiple grippers 4 are set to open and close immediately after the rotation of the multiple grippers 4 has ended.

[0075] like Figure 3 , 5As shown, an end position sensor 42 is provided behind the internal thread component 27 to detect when the lead screw shaft 28 has moved to the foremost end position of its movement range. An initial position sensor 41 is provided behind the end position sensor 42 to detect when the lead screw shaft 28 has moved to the initial position of the rearmost end of its movement range. The initial position sensor 41 and the end position sensor 42 are sensors called Hall effect sensors (HIDs) used to detect magnetic fields. The initial position sensor 41 is fixed to the main housing 11 above the lead screw shaft 28. The end position sensor 42 is supported above the lead screw shaft 28 by the main housing 11 in a manner that allows it to move in the front-back direction.

[0076] like Figure 1 , 5 As shown, a position adjustment mechanism 44 for moving the terminal position sensor 42 in the front-back direction is provided on the upper part of the main housing 11. A slot 11a extending vertically through the main housing 11 and linearly in the front-back direction is provided on the upper surface of the main housing 11. The position adjustment mechanism 44 has an operating part 44a that passes through the slot 11a and protrudes from the upper surface of the main housing 11. The terminal position sensor 42 is supported inside the main housing 11 and at the lower end of the operating part 44a. The terminal position sensor 42 can slide along the slot 11a in the front-back direction together with the operating part 44a. The front-back position of the terminal position sensor 42 can be changed by sliding the operating part 44a with the user's finger.

[0077] like Figure 3 , 5 As shown, a magnet 43 is mounted on the upper rear side of the lead screw shaft 28. An initial position sensor 41 detects the position of the lead screw shaft 28 and the wedge 3 at the point in time when they overlap with the magnet 43 in the front-rear direction, and uses this as the initial position. An end position sensor 42 detects the position of the lead screw shaft 28 and the wedge 3 at the point in time when they overlap with the magnet 43 in the front-rear direction, and uses this as the end position.

[0078] As described above, the pipe expander 1 for expanding the end diameter of a fluid pipe made of synthetic resin has the following features: Figures 5-7An electric motor 21 is housed within the main housing 11 as shown. The tube expander 1 has a lead screw 28 disposed on the main housing 11 parallel to or movable along the axis of the output shaft 21a of the electric motor 21. The tube expander 1 has an internal threaded component 27 that engages with the lead screw 28 and causes the lead screw 28 to move back and forth by rotating about its axis. The tube expander 1 has a gear 26 that transmits the rotation of the output shaft 21a of the electric motor 21 by engaging with the internal threaded component 27. The tube expander 1 has a wedge 3 extending forward from the lead screw 28. The tube expander 1 has a plurality of jaws 4 that are closably connected to the main housing 11 in a manner that allows them to open and close radially outward as the wedge 3 pushes against the lead screw 28 as they advance together.

[0079] Therefore, the electric motor 21 is arranged with its output shaft 21a extending parallel to the lead screw shaft 28. Thus, the electric motor 21 is arranged to extend along the lead screw shaft 28 in the front-rear direction and is located close to the lead screw shaft 28. Alternatively, the electric motor 21 is arranged with its output shaft 21a extending coaxially with the lead screw shaft 28. Thus, the electric motor 21 is positioned near the lead screw shaft 28. This allows the heavy electric motor 21 to be located close to the center of the main body housing 11 where the lead screw shaft 28 is located. Therefore, weight balance is good, and the tube expander 1 can be held in a stable state. This ensures good operability of the tube expander 1.

[0080] like Figure 5 As shown, the tube expander 1 has a handle 5 extending downward from the main body housing 11. The handle 5 is positioned between the electric motor 21 and the plurality of grippers 4 in the front-to-back direction. The electric motor 21 is positioned below the lead screw shaft 28. Therefore, the electric motor 21 and the plurality of grippers 4 are configured in a way that is well balanced in weight relative to the handle 5. This improves the operability of the tube expander 1 when the user holds the handle 5.

[0081] like Figure 5 As shown, at least a portion of the lead screw 28 overlaps with the handle 5 in the longitudinal direction. Therefore, the tube expander 1 can be shortened in the longitudinal direction. Consequently, the torque of the tube expander 1 about its center of gravity can be reduced, thereby further improving operability.

[0082] like Figure 5 As shown, a planetary reduction mechanism 23 for slowing down the output of the output shaft 21a is provided between the output shaft 21a of the electric motor 21 and the lead screw shaft 28. Therefore, the planetary reduction mechanism 23 can be compactly arranged in the power transmission path from the electric motor 21 to the lead screw shaft 28. In addition, by making the power transmission path from the electric motor 21 to the lead screw shaft 28 a minimum path, power transmission loss can be suppressed.

[0083] like Figure 4 , 5 As shown, the tube expander 1 has rotary drive rings 34, 35, and 36 connected to the rear of multiple grippers 4. The tube expander 1 has a gripper rotation mechanism 30, which rotates the rotary drive rings 34, 35, and 36 via the output of an electric motor 21, thereby causing the multiple grippers 4 to rotate circumferentially. The rotary drive rings 34, 35, and 36 are positioned in front of the internal thread member 27. Therefore, the internal thread member 27, the rotary drive rings 34, 35, and 36, and the multiple grippers 4 are arranged in a front-rear direction extending along the lead screw shaft 28. This allows the center of gravity of the tube expander 1 to be close to the lead screw shaft 28. Consequently, the stability of the tube expander 1 when held is improved.

[0084] like Figure 4 , 5 As shown, the tube expander 1 has an end cap 2 that supports multiple jaws 4 in an openable and closable manner and restricts the forward and backward movement of the multiple jaws 4. The tube expander 1 has a front mechanism housing 12, a first central mechanism housing 13, and a rear mechanism housing 15 arranged sequentially from front to rear within the main body housing 11. The tube expander 1 has a bolt 16 connecting the front mechanism housing 12 and the rear mechanism housing 15. The front mechanism housing 12 is made of iron and is used to support the end cap 2. The rear mechanism housing 15 is made of iron and is used to support the rear end of the internally threaded component 27. The first central mechanism housing 13 is formed of a material lighter than iron.

[0085] Therefore, the structure is divided into a front mechanism housing 12, a first central mechanism housing 13, and a rear mechanism housing 15 along the front-rear direction. The front mechanism housing 12, including the end cap 2 and the supporting end cap 2, is forcefully pushed forward by the multiple grippers 4 when they open. The internal thread component 27 is forcefully pushed backward by the reaction force that moves the lead screw shaft 28 forward. For example, in the case where the front mechanism housing 12, the first central mechanism housing 13, and the rear mechanism housing 15 are integrated as a single component, a strong tensile force is generated at the front and rear ends along the front-rear direction when the grippers 4 expand their diameter. Therefore, the entire mechanism housing needs to be designed with high strength. The front mechanism housing 12, the first central mechanism housing 13, and the rear mechanism housing 15 are divided along the front-rear direction, and the front mechanism housing 12 and the rear mechanism housing 15 are made of iron. This allows the tensile force along the front-rear direction to be distributed to the high-strength front mechanism housing 12 and the rear mechanism housing 15, respectively. Furthermore, by using lightweight materials to house the first central mechanism housing 13, the tube expanding tool 1 can be made lighter.

[0086] like Figure 2 , 5As shown, the tube expanding tool 1 has a second central mechanism housing 14 between the first central mechanism housing 13 and the rear mechanism housing 15. The front mechanism housing 12, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 each have engaging portions 12b, 13a, 13b, 14a, 14b, and 15b at each end, which overlap in the front-rear direction for adjacent contact. Therefore, by overlapping engaging portions 12b and 13a in the front-rear direction, the front mechanism housing 12 and the first central mechanism housing 13 can be positioned relative to each other with high precision. Furthermore, the engaging portions 13b and 14a of the first central mechanism housing 13 and the second central mechanism housing 14, and the engaging portions 14b and 15b of the second central mechanism housing 14 and the rear mechanism housing 15 can also be positioned with high precision. Therefore, the assembly of each mechanism housing is good, and the wobbling of the internally threaded components 27 and the like housed inside can be suppressed.

[0087] like Figure 5 As shown, a main shaft 24, which rotates integrally with the gear 26, is disposed in front of the output shaft 21a. The first central mechanism housing 13 and the second central mechanism housing 14 support the main shaft bearings 24b and 24c, which rotatably support the main shaft 24, and the internal thread component bearings 27c and 27d, which rotatably support the internal thread component 27. Therefore, the main shaft bearings 24b and 24c and the internal thread component bearings 27c and 27d are subjected to almost no force in the front-to-back direction. Thus, the main shaft 24 and the internal thread component 27 can be adequately supported by the first central mechanism housing 13 and the second central mechanism housing 14, whose strength is lower than that of the front mechanism housing 12 and the rear mechanism housing 15. This reduces the need for iron-made parts, thereby making the tube expanding tool 1 lighter.

[0088] like Figure 5 As shown, the rear mechanism housing 15 supports the thrust bearing 27e, which abuts against the rear end of the internal threaded component 27. Therefore, the internal threaded component 27 is forcefully pushed rearward as the lead screw shaft 28 moves forward. The rear mechanism housing 15 can withstand the force pushing the internal threaded component 27 rearward via the thrust bearing 27e. Therefore, the internal threaded component 27 can rotate with high precision about the axis of the lead screw shaft 28. Consequently, the lead screw shaft 28 can move with high precision in the front-to-back direction.

[0089] like Figure 5 As shown, balls 28b are clamped in the engagement portion of the lead screw shaft 28 and the internal thread component 27. Therefore, the transmission efficiency of the driving force is improved by the balls 28b clamped in the engagement portion. Thus, the rotational drive of the internal thread component 27 relative to the lead screw shaft 28 can be efficiently converted into the forward and backward movement of the lead screw shaft 28.

[0090] When the end position sensor 42 is moved forward, the end position of the wedge 3 is set further forward. Therefore, the approximately conical wedge 3, at its end position, pushes the multiple grippers 4 radially outward from its larger diameter rear outer circumference. This increases the force pushing the grippers 4 radially outward, thereby increasing the radially outward expansion width of the grippers 4. For example, in situations where the air temperature, the fluid pipe temperature is high, and the expanded fluid pipe contracts rapidly, moving the end position sensor 42 forward allows for a larger expansion of the fluid pipe's end diameter.

[0091] By moving the end position sensor 42 rearward, the end position of the wedge 3 can be set further rearward. Therefore, the approximately conical wedge 3, at its end position, pushes the multiple grippers 4 radially outward from the outer periphery of its smaller diameter in the front-rear direction. This reduces the force pushing the multiple grippers 4 radially outward, thus decreasing the radial expansion width of the grippers 4. For example, in cases of low temperature and slow contraction of the expanded fluid tube, moving the end position sensor 42 forward can reduce the expansion width at the end of the fluid tube.

[0092] Figures 5-7 When the multiple grippers 4 shown open radially outward, they are subjected to a large load from the fluid tube, causing the ends of the fluid tube to expand. On the other hand, the load on the multiple grippers 4 when they rotate circumferentially within the fluid tube is smaller than when the ends of the fluid tube are expanded. Therefore, the output of the electric motor 21 required to open the multiple grippers 4 radially outward is larger than the output of the electric motor 21 required to rotate the multiple grippers 4. It is assumed that the upper limit of the current flowing in the electric motor 21 is always set to a constant value. Sometimes, for example, during rotation, the grippers 4 may be unable to rotate due to gripping the inner circumferential surface of the fluid tube. In this case, current is still supplied to the electric motor 21 until the upper limit is reached. Therefore, excessive force is applied to the grippers 4 that cannot rotate, and the grippers 4 may break.

[0093] In this embodiment, to suppress excessive force applied to the gripper 4, the upper limit of the current flowing in the electric motor 21 during the rotational range of the gripper 4 is set as a first upper limit. The upper limit of the current flowing in the electric motor 21 during the radially outward expansion range of the multiple grippers 4 is set as a second upper limit. The first upper limit is set to a value lower than the second upper limit, for example, a value lower than 70%, 50%, or 30% of the second upper limit. Therefore, if the gripper 4 becomes unable to rotate in the rotational range, the drive of the electric motor 21 is stopped at the first upper limit, which is lower than the second upper limit. Thus, it is possible to suppress excessive force generated by the non-rotating gripper 4. Controller 45 (see reference) Figure 1The rotation range and the expansion range are detected based on the rotation speed of the electric motor 21 and the front and rear positions of the wedge 3.

[0094] like Figure 14 As shown, when the controller 45 receives an on signal from the switch body 6a, it supplies electrical power from the battery 8 to the electric motor 21, causing the electric motor 21 to start. The controller 45 detects the rotational speed of the electric motor 21 by receiving a detection signal of the phase of the rotor 21c from the speed detection sensor 21d installed on the electric motor 21. The initial position sensor 41 sends a detection signal to the controller indicating the initial position of the lead screw shaft 28 when the magnet 43 is detected (see reference). Figure 5 The terminal position sensor 42 sends a detection signal to the controller 45 indicating the terminal position of the lead screw shaft 28 when the magnet 43 is detected.

[0095] Figure 14 The controller 45 shown defines the rotation interval as the period from receiving the detection signal from the initial position sensor 41 until the electric motor 21 rotates at a specified speed. The controller 45 defines the expansion interval as the period from the end of the rotation interval until the end position sensor 42 detects that the lead screw shaft 28 is at the end position. The specified speed of the electric motor 21 is determined, for example, by the slots 32a and 32b of the power conversion ring 32 (see reference). Figure 9 The shape of the main spindle 24, the feed rate of the lead screw 28 and the linear motion component 31 per revolution (refer to...) Figures 5-7 The electric motor 21 is preset and stored in the controller 45. The controller 45 (see reference 45) Figure 1 Switching between forward and reverse rotation changes the rotation speed. This allows for changes to the moving direction and speed of the wedge 3, as well as the rotation direction and speed of the gripper 4.

[0096] As described above, the pipe expander 1 for expanding the end diameter of a fluid pipe made of synthetic resin has the following features: Figure 5 The controller 45, as shown, switches the output shaft 21a of the electric motor 21 to forward and reverse rotation (see reference). Figure 1 The pipe expander 1 has an internally threaded component 27 that rotates via an electric motor 21. The pipe expander 1 has a lead screw 28 that engages with the internally threaded component 27 and moves back and forth between an initial rearward position and a forward terminal position due to the rotation of the internally threaded component 27. The pipe expander 1 has a wedge 3 extending forward from the lead screw 28. The pipe expander 1 has multiple grippers 4 that open radially outward when pushed by the wedge 3 as it advances together with the lead screw 28. The pipe expander 1 has a terminal position sensor 42 that sends a signal to a controller 45 by detecting the lead screw 28 at its terminal position. The terminal position sensor 42 is configured to move in the back-and-forth direction. The terminal position of the lead screw 28 is variable based on the position of the terminal position sensor 42.

[0097] Therefore, by moving the end position sensor 42 forward, the end position of the wedge 3 can be set further forward. Consequently, the force with which the wedge 3 pushes the multiple grippers 4 radially outward at the end position increases. This increases the radially outward expansion width of the multiple grippers 4. Therefore, for example, in cases of high temperature and rapid fluid tube contraction, the end of the fluid tube can be expanded to a larger diameter. Conversely, by moving the end position sensor 42 backward, the end position of the wedge 3 can be set further backward. Consequently, the force with which the wedge 3 pushes the multiple grippers 4 radially outward at the end position decreases. This decreases the radially outward expansion width of the multiple grippers 4. Therefore, for example, in cases of low temperature and slow fluid tube contraction, the end of the fluid tube can be expanded to a smaller diameter. Thus, the expansion width of the grippers 4 can be varied according to the air temperature, the fluid tube temperature, etc.

[0098] like Figure 3 , 5 As shown, the tube expanding tool 1 has an initial position sensor 41 for detecting the lead screw 28 at its initial position. Therefore, by detecting the initial and final positions of the lead screw 28, the positions of the lead screw 28 and the wedge 3 in the front-rear direction can be detected with high precision.

[0099] like Figure 5 As shown, the terminal position sensor 42 has a Hall effect IC disposed on the main housing 11. A magnet 43 is disposed on the lead screw 28. Therefore, the structure for detecting the terminal position of the lead screw 28 can be made simple and compact. Therefore, the main housing 11 containing the terminal position sensor 42 can be made compact.

[0100] like Figure 1 , 5 As shown, the terminal position sensor 42 has an operating part 44a that protrudes outward from the main body housing 11. Therefore, the user can move the terminal position sensor 42 by operating the operating part 44a from outside the main body housing 11. Thus, the terminal position sensor 42 can be easily moved to a target position.

[0101] like Figure 1 As shown, the tube expander 1 has a handle 5 extending downward from the main body housing 11. An operating section 44a protrudes from the upper surface of the main body housing 11. Therefore, the operating section 44a is positioned above the main body housing 11, allowing the user to operate it while visually observing it. This ensures good operability of the operating section 44a.

[0102] like Figure 5As shown, the tube expander 1 has a gripper rotation mechanism 30, which rotates multiple grippers 4 circumferentially via the output of an electric motor 21. Controller 45 (see reference) Figure 1 The current can be supplied to the electric motor 21 according to a first upper limit value and a second upper limit value of the current. The first upper limit value of the current is the value of the current flowing in the electric motor 21 during the rotation interval when the multiple grippers 4 rotate; the second upper limit value of the current is the value of the current flowing in the electric motor 21 during the expansion interval when the multiple grippers 4 open radially outward. Therefore, the upper limit value of the current flowing in the electric motor 21 can be changed in the rotation interval and the expansion interval. Therefore, for example, it is possible to suppress the situation where the electric motor 21 continues to drive when the grippers 4 cannot rotate. As a result, it is possible to suppress excessive load applied to the grippers 4, wedges 3, gripper rotation mechanism 30, etc.

[0103] like Figure 14 As shown, the tube expander 1 has a speed detection sensor 21d that sends a signal to the controller 45 by detecting the rotational speed of the electric motor 21. The controller 45 sets the rotation range and the expansion range based on the signal sent by the speed detection sensor 21d and the detection signal that the lead screw 28 has moved to the end position or the initial position. Therefore, when the end position sensor 42 is moved to change the end position of the lead screw 28, the rotation range and the expansion range can be reset. Therefore, the rotation and expansion actions of the gripper 4 can be appropriately controlled so that the fluid tube can be expanded with an expansion width corresponding to the contraction speed of the fluid tube.

[0104] like Figure 5 As shown, the first upper limit value of the current flowing in the electric motor 21 is set lower than the second upper limit value. Therefore, the upper limit value of the current flowing in the electric motor 21 is reduced during the rotational range where the load applied to the gripper 4 and the gripper rotation mechanism 30 is small. Therefore, it is possible to suppress excessive driving of the electric motor 21 during the rotational range. As a result, the load applied to the gripper 4 and the gripper rotation mechanism 30 can be minimized.

[0105] like Figures 5-7 As shown, the rotation interval is the interval in which the wedge 3 advances and precedes the diameter expansion interval. Therefore, after rotating circumferentially along the wedge 3, the multiple grippers 4 expand radially. By clearly distinguishing the rotational and diameter expansion actions of the multiple grippers 4, unintentional loads applied to the grippers 4 and the gripper rotation mechanism 30 can be suppressed.

[0106] Reference Figures 5-7The rotation interval is the interval after the wedge 3 retracts and follows the diameter expansion interval. Therefore, after the multiple grippers 4 close together radially inward, they rotate circumferentially along the wedge 3. In this case, since the rotation and diameter expansion actions of the multiple grippers 4 are clearly distinguished, unintentional loads applied to the grippers 4 and the gripper rotation mechanism 30 can be suppressed.

[0107] like Figure 5 As shown, balls 28b are clamped in the engagement portion of the lead screw shaft 28 and the internal thread component 27. Therefore, the transmission efficiency of the driving force is improved by the balls 28b clamped in the engagement portion. Thus, the rotational drive of the internal thread component 27 relative to the lead screw shaft 28 can be efficiently converted into the forward and backward movement of the lead screw shaft 28.

[0108] Next, according to Figures 15-17 To illustrate another embodiment of the present invention. For example... Figure 15 As shown, the tube expanding tool 50 of the second embodiment has a sensor positioning mechanism (position adjustment mechanism) 53, which replaces... Figure 5 The first embodiment of the tube expanding tool 1 shown has a position adjustment mechanism 44. An initial position operation unit 54 is provided on the sensor positioning mechanism 53, capable of changing the position of the initial position sensor 41 in the front-rear direction. An end position operation unit 55 is provided on the sensor positioning mechanism 53, capable of changing the position of the end position sensor 42 in the front-rear direction. In the following description, only the parts that differ from the first embodiment of the tube expanding tool 1 will be described in detail.

[0109] like Figure 15 , 16 As shown, multiple second jaws 51 can be installed at the front of the tube expander 50 instead of multiple jaws 4. The multiple jaws 4 are used, for example, to expand fluid tubes with nominal diameters of 0.5 inches, 0.75 inches, 1 inch, etc. The multiple jaws 51 are used, for example, to expand fluid tubes with a nominal diameter of 1.5 inches, etc. When the multiple jaws 4, 51 expand the fluid tube, a radially outward force from the wedge 3 and a radially inward force from the fluid tube due to the reaction force of the expanding force act on the multiple jaws 4, 51. Therefore, a bending force acts on each of the jaws 4, 51. The larger the size of the fluid tube, the greater the bending force. The jaws 51 are set to have a larger radial wall thickness than the jaws 4 in order to improve durability against the bending force.

[0110] like Figure 15As shown, an annular receiving groove 51a with a circular arc cross-section is provided on the radial outer periphery of the rear part of each gripper 51. The annular receiving grooves 51a of multiple grippers 51 are connected in the circumferential direction to form an annular groove. Multiple grippers 51 are connected in the circumferential direction by a ring 51b that is inserted into the annular receiving groove 51a and is elastically expandable and contractible. The gripper support groove 2a on the inner circumferential surface of the end cap 2 allows the ring 51b to move radially and restricts the movement of the ring 51b in the front-rear direction. Multiple grippers 51 open and close radially with the ring 51b supported by the gripper support groove 2a as the center.

[0111] Reference Figure 15 , 16 Remove the end cap 2, which connects to multiple grippers 4, from the external thread 12a of the front mechanism housing 12, and tighten the end cap 2, which connects to multiple second grippers 51, onto the external thread 12a. This allows for the replacement of multiple grippers 4 and multiple second grippers 51.

[0112] Reference Figure 15 , 16 Assuming the initial position of wedge 3 is fixed close to the inner peripheral wall 51c of gripper 51, when multiple grippers 4 are installed instead of multiple second grippers 51, a distance D in the front-rear direction will be generated between the inner peripheral wall 4d of gripper 4 and wedge 3. During the period when wedge 3 moves from its initial position within the range of distance D, wedge 3 does not contact the multiple grippers 4, and the multiple grippers 4 do not open radially outward. Therefore, the opening and closing time of each cycle of opening and closing of the multiple grippers 4 is extended by the amount of the moving distance D. The tube expanding tool 50 of this embodiment can change the initial position of wedge 3 and lead screw shaft 28 by moving the initial position sensor 41 in the front-rear direction. Thus, for example, Figure 16 As shown by the imaginary line, the initial position of the wedge 3 can be changed to a position where the wedge 3 and the inner peripheral wall 51c of the gripper 51 are close to each other.

[0113] like Figure 17As shown, the initial position operating part 54 can slide in the front-to-back direction along the slot 52a of the main body housing 52. A sensor holding part 54b for holding the initial position sensor 41 is provided at the lower part of the initial position operating part 54. The upper part of the initial position operating part 54 is located outside (upper side) of the slot 52a and is configured as a roughly rectangular plate extending laterally beyond the slot 52a. A spring holding groove 54a is provided on the lower surface of the upper part of the initial position operating part 54. One spring holding groove 54a is provided at the front and one at the rear of the initial position operating part 54. The two ends of the leaf spring 56 are held in each spring holding groove 54a in an inserted manner without falling out. The leaf spring 56 is configured as a roughly M-shape, with a downwardly protruding engaging part 56a in the center. The lower surface of the engaging part 56a is arc-shaped. The engaging part 56a can move in the vertical direction by utilizing the elasticity of the leaf spring 56 held in the initial position operating part 54.

[0114] like Figure 17 As shown, the terminal position operating part 55 can slide in the front-to-back direction along the slot 52a of the main body housing 52. The terminal position operating part 55 is configured to have approximately the same shape as the initial position operating part 54. A sensor holding part 55b for holding the terminal position sensor 42 is provided at the lower part of the terminal position operating part 55. A spring holding groove 55a is provided on the lower surface of the upper part of the terminal position operating part 55. One spring holding groove 55a is provided at the front and one at the rear of the terminal position operating part 55. The two ends of the leaf spring 57 are held in a pair of spring holding grooves 55a in a way that allows them to be inserted without falling out. The leaf spring 57 is configured to have approximately the same shape as the leaf spring 56, and has a downwardly protruding engaging part 57a in the center. The lower surface of the engaging part 57a is arc-shaped. The engaging part 57a can move in the vertical direction by utilizing the elasticity of the leaf spring 57 held in the terminal position operating part 55.

[0115] like Figure 17 As shown, a plurality of engaging recesses 52b and 52c are provided on the sidewall of the slot 52a of the main body shell 52. The engaging recesses 52b and 52c are recessed into a hemispherical shape from the upper surface of the main body shell 52 downward. The plurality of engaging recesses 52b are formed at predetermined intervals along the front-rear direction at the rear of the slot 52a. The plurality of engaging recesses 52c are formed at predetermined intervals along the front-rear direction at the front of the slot 52a.

[0116] like Figure 17As shown, when the engaging portion 56a of the leaf spring 56 moves to the same forward / backward position as any one of the multiple engaging recesses 52b, it moves downward and elastically engages with the engaging recess 52b. Thus, the initial position operating portion 54 is positioned at a predetermined forward / backward position. By applying a force in the forward / backward direction greater than a predetermined value to the initial position operating portion 54, the engaging portion 56a disengages from the engaging recess 52b, allowing the initial position operating portion 54 to slide in the forward / backward direction. In this way, the initial position operating portion 54 is positioned at multiple predetermined forward / backward positions in a manner that provides a sense of control (click) and allows movement in the forward / backward direction. For example, in the case of mounting multiple grippers 4 with thinner radial walls, the initial position operating portion 54 is moved to a forward position. For example, in the case of mounting multiple second grippers 51 with thicker radial walls, the initial position operating portion 54 is moved to a rearward position.

[0117] like Figure 17 As shown, when the engaging portion 57a ​​of the leaf spring 57 moves to the same forward / backward position as any one of the multiple engaging recesses 52c, it moves downward and elastically engages with the engaging recess 52c. Thus, the end position operating portion 55 is positioned at a predetermined forward / backward position. By applying a predetermined or greater force in the forward / backward direction to the end position operating portion 55, the engaging portion 57a ​​disengages from the engaging recess 52c, allowing the end position operating portion 55 to slide in the forward / backward direction. In this way, the end position operating portion 55 is positioned at multiple predetermined forward / backward positions in a controlled manner and is capable of moving in the forward / backward direction. For example, in cases of high temperature and rapid fluid tube contraction, the end position operating portion 55 is moved to a forward position. For example, in cases of low temperature and slow fluid tube contraction, the end position operating portion 55 is moved to a rearward position.

[0118] As described above, the tube expander 50 for expanding the end diameter of a fluid tube made of synthetic resin has the following characteristics: Figure 16 The controller 45, as shown, switches the output shaft of the electric motor 21 to forward and reverse rotation (see reference). Figure 1The pipe expander 50 has an internally threaded component 27 that rotates via an electric motor 21. The pipe expander 50 has a lead screw 28 that engages with the internally threaded component 27 and moves back and forth between an initial rearward position and a final forward position due to the rotation of the internally threaded component 27. The pipe expander 50 has a wedge 3 extending forward from the lead screw 28. The pipe expander 50 has multiple grippers 4 that open radially outward when pushed by the wedge 3 as it advances together with the lead screw 28. The pipe expander 50 has two sensors: an initial position sensor 41 and a final position sensor 42, which send signals to a controller 45 by detecting the position of the lead screw 28 at its initial or final position. The initial position sensor 41 and the final position sensor 42 are configured to move in the back-and-forth direction. The initial and final positions of the lead screw 28 are variable based on the positions of the initial position sensor 41 and the final position sensor 42.

[0119] Therefore, by moving the initial position sensor 41 forward, the initial position of the wedge 3 can be set further forward. This shortens the time it takes for the wedge 3 to move from its initial position until it comes into contact with the grippers 4. Consequently, the time for one cycle of opening and closing the grippers 4 is shortened, thus reducing operation time. By moving the initial position sensor 41 backward, the initial position of the wedge 3 can be set further backward. Therefore, for example, when using grippers 51 with a radially thicker wall, the initial position of the wedge 3 can be moved backward so that the wedge 3 at its initial position does not interfere with the grippers 51.

[0120] like Figure 15 , 16 As shown, the initial position sensor 41 and the terminal position sensor 42 have an initial position operation section 54 and a terminal position operation section 55 protruding outward from the main body housing 11. Therefore, the user can move the initial position sensor 41 or the terminal position sensor 42 by operating the initial position operation section 54 or the terminal position operation section 55 from outside the main body housing 11. Thus, the initial position sensor 41 and the terminal position sensor 42 can be easily moved to the target position.

[0121] like Figure 15 , 16 As shown, the pipe expander 50 can replace the multiple clamps 4 by installing multiple second clamps 51 with different wall thicknesses in the radial direction of the multiple clamps 4. Therefore, a single pipe expander 50 can be used to expand the diameter of various fluid pipes with different pipe diameters (nominal diameters).

[0122] like Figure 17As shown, the pipe expanding tool 50 has a sensor positioning mechanism 53, which can releasably position the initial position sensor 41 and the terminal position sensor 42 at multiple positions in the front-rear direction. Therefore, the initial position sensor 41 can be positioned at one of the preferred positions that serve as the initial position of the wedge 3. Alternatively, the terminal position sensor 42 can be positioned at one of the preferred positions that serve as the terminal position of the wedge 3. Thus, the user does not need to perform fine-tuning of the initial and terminal positions, thereby improving usability. Furthermore, unintentional movement of the positioned initial position sensor 41 and terminal position sensor 42 can be suppressed.

[0123] Next, according to Figure 18 To illustrate another embodiment of the present invention, the tube expanding tool 60 of the third embodiment replaces... Figure 16 The second embodiment of the tube expander tool 50 shown includes a sensor positioning mechanism (position adjustment mechanism) 61 in its sensor positioning mechanism 53. The sensor positioning mechanism 61 is provided with an initial position operation unit 62 capable of changing the position of the initial position sensor 41 in the front-rear direction and an end position operation unit 63 capable of changing the position of the end position sensor 42 in the front-rear direction. In the following description, only the parts that differ from the tube expander tool 1 of the first embodiment and the tube expander tool 50 of the second embodiment will be described in detail.

[0124] like Figure 18 As shown, the initial position operation unit 62 can slide in the front-to-back direction along the slot 52a of the main body housing 52. A sensor holding part 62b for holding the initial position sensor 41 is provided at the lower part of the initial position operation unit 62. The upper part of the initial position operation unit 62 is located outside (upper side) of the slot 52a and is configured as a roughly rectangular plate extending to the left and right of the slot 52a. A slot-shaped ball receiving groove 62a extending upward is provided on the lower surface of the upper part of the initial position operation unit 62. A positioning ball plunger 64 is received in the ball receiving groove 62a in a manner that prevents it from falling out. The positioning ball 64 is composed of a ball 64a held so as to be able to protrude from the lower end of the ball receiving groove 62a and a compression spring 64b that applies force downward to the ball 64a.

[0125] like Figure 18As shown, the terminal position operation unit 63 can slide in the front-to-back direction along the slot 52a of the main body housing 52. The terminal position operation unit 63 is configured to have approximately the same shape as the initial position operation unit 62. A sensor holding part 63b for holding the terminal position sensor 42 is provided at the lower part of the terminal position operation unit 63. A slotted ball receiving groove 63a extending upward is provided on the lower surface of the upper part of the terminal position operation unit 63. A positioning ball 65 is received in the ball receiving groove 63a in a manner that prevents it from falling out. The positioning ball 65 consists of a ball 65a held so as to protrude from the lower end of the ball receiving groove 63a and a compression spring 65b that applies downward force to the ball 65a.

[0126] like Figure 18 As shown, when the ball 64a of the positioning ball 64 moves to the same front-rear position as any one of the plurality of engaging recesses 52b, it moves downward and elastically engages with the engaging recess 52b. Thus, the initial position operating part 62 is positioned at a predetermined front-rear position. By applying a force in the front-rear direction greater than a predetermined amount to the initial position operating part 62, the ball 64a disengages from the engaging recess 52b, allowing the initial position operating part 62 to slide in the front-rear direction. In this way, the initial position operating part 62 is positioned at a plurality of predetermined front-rear positions in a controlled manner and is capable of moving in the front-rear direction. The initial position operating part 62 moves, for example, according to the type (radial thickness, size) of the plurality of jaws mounted on the tube expander 60.

[0127] like Figure 18 As shown, when the ball 65a of the positioning ball 65 moves to the same forward / backward position as any one of the plurality of engaging recesses 52c, it moves downward and elastically engages with the engaging recess 52c. Thus, the end position operating unit 63 is positioned at a predetermined forward / backward position. By applying a predetermined or greater force in the forward / backward direction to the end position operating unit 63, the ball 65a disengages from the engaging recess 52c, allowing the end position operating unit 63 to slide in the forward / backward direction. In this way, the end position operating unit 63 is positioned at a plurality of predetermined forward / backward positions in a controlled manner and is capable of moving in the forward / backward direction. The end position operating unit 63 moves, for example, according to the temperature.

[0128] Next, according to Figure 19 To illustrate another embodiment of the present invention, the tube expander 70 of the fourth embodiment includes a sensor positioning mechanism (position adjustment mechanism) 71 that automatically moves the initial position sensor 41 and the terminal position sensor 42 in the front-back direction. The sensor positioning mechanism 71 includes an initial position operation section 72 that holds the initial position sensor 41 in a manner movable in the front-back direction, and a terminal position operation section 73 that holds the terminal position sensor 42 in a manner movable in the front-back direction. In the following description, only the parts that differ from the tube expander 1 of the first embodiment will be described in detail.

[0129] like Figure 19 As shown, the initial position operation unit 72 includes a solenoid 72a. The solenoid 72a is activated by operating the initial position operation switch 72b. When the solenoid 72a is activated, the initial position sensor 41 moves forward or backward together with the initial position operation unit 72. The solenoid 72a is activated for a predetermined time, causing the initial position sensor 41 to move to a predetermined position, after which it stops. The initial position operation switch 72b is, for example, a button, a toggle switch, a dial switch, etc., and is provided, for example, on the grip 5 (see reference). Figure 1 Multiple movable positions of the initial position sensor 41, for example, depending on the type of gripper that can be mounted on the pipe expander 70, are pre-stored in the storage unit of the controller 45.

[0130] like Figure 19 As shown, the terminal position operation unit 73 includes a solenoid 73a. The solenoid 73a is activated by operating the terminal position operation switch 73b. When the solenoid 73a is activated, the terminal position sensor 42 moves forward or backward together with the terminal position operation unit 73. The solenoid 73a is activated for a predetermined time, causing the terminal position sensor 42 to move to a predetermined position, after which it stops. The terminal position operation switch 73b is arranged with the initial position operation switch 72b, having the same structure. Multiple movable positions of the terminal position sensor 42, such as the contraction speed of the fluid pipe at predetermined intervals at various temperatures, are pre-stored in the storage unit of the controller 45.

[0131] Next, according to Figure 20 To illustrate another embodiment of the present invention, the tube expander 80 of the fifth embodiment includes a sensor positioning mechanism (position adjustment mechanism) 81 that automatically moves the initial position sensor 41 and the terminal position sensor 42 in the front-back direction. The sensor positioning mechanism 81 includes an initial position operation section 72 that holds the initial position sensor 41 in a manner movable in the front-back direction, and a terminal position operation section 73 that holds the terminal position sensor 42 in a manner movable in the front-back direction. In the following description, only the parts that differ from the tube expander 1 of the first embodiment and the tube expander 70 of the fourth embodiment will be described in detail.

[0132] like Figure 20 As shown, the tube expander 80 has a tag reader 85. The tag reader 85 is, for example, located on the tool body 10 on which the end cap 2 for holding the gripper 84 is mounted (see reference). Figure 1 The front part of the ) . In multiple grippers 84 or end cap 2 (refer to Figure 1An NFC tag 84a is installed on the device. The tag reader 85 is able to read the information recorded on the NFC tag 84a via wireless communication.

[0133] like Figure 20 As shown, the controller 45 includes an initial position setting unit 82, an end position setting unit 83, and a tag discrimination unit 86. The tag discrimination unit 86 determines the type of gripper 84 based on the information from the NFC tag 84a read by the tag reader 85. The initial position setting unit 82 sets the initial positions of the wedge 3 and the lead screw shaft 28 (see reference) based on the type of gripper determined by the tag discrimination unit 86 and the rotational speed (rotation angle) of the electric motor 21 detected by the rotational speed detection sensor 21d. Figure 5 The solenoid 72a of the initial position operation unit 72 moves the initial position sensor 41 to the initial position set by the initial position setting unit 82.

[0134] like Figure 20 As shown, the pipe expanding tool 80 has a temperature sensor 87 that detects air temperature. The end position setting unit 83 sets the end positions of the wedge 3 and the lead screw shaft 28 based on the air temperature detected by the temperature sensor 87 and the rotational speed (rotation angle) of the electric motor 21 detected by the rotational speed detection sensor 21d (see reference). Figure 7 The solenoid 73a of the terminal position operation unit 73 moves the terminal position sensor 42 to the terminal position set by the terminal position setting unit 83.

[0135] Next, according to Figure 21 To illustrate another embodiment of the invention, the tube expanding tool 90 of the sixth embodiment includes a sensor positioning mechanism (position adjustment mechanism) 91 that automatically moves the initial position sensor 41 and the terminal position sensor 42 in the front-back direction. The tube expanding tool 90 replaces... Figure 20 The tag reader 85 and tag discrimination unit 86 shown in the fifth embodiment have a bus current measuring unit 92. The bus current measuring unit 92 monitors the bus current value supplied to the electric motor 21.

[0136] Reference Figure 21First, a specified type of gripper is installed on the tube expander 90, and the switch body 6a is turned on, thereby driving the electric motor 21. The bus current measuring unit 92 measures the bus current. The initial position setting unit 82 determines the type of gripper installed on the tube expander 90 based on the maximum value of the bus current monitored by the bus current measuring unit 92 and the total electrical power of the bus current. Specifically, the bus current value increases when multiple grippers begin to open radially, and reaches its maximum when multiple grippers are opened to their maximum. Then, the bus current value decreases when multiple grippers close radially. The type of gripper (radial thickness, size) is determined based on the characteristics of the change in the bus current value. Furthermore, the initial position setting unit 82 sets the initial position of the wedge 3 and the lead screw shaft 28 based on the determined type of gripper (see reference). Figure 5 The solenoid 72a moves the initial position sensor 41 toward the initial position set by the initial position setting unit 82. In this way, during the use of multiple grippers of the same type, the initial positions of the wedge 3 and the lead screw shaft 28 become the positions after the initial position sensor 41 has moved.

[0137] Various modifications can be made to the embodiment described above. An example is a tube expander 1 with six grippers 4. Alternatively, it may have, for example, five or fewer, or seven or more grippers 4. An example is a structure in which the electric motor 21 is positioned below the lead screw 28 and above the rear of the handle 5. Alternatively, the electric motor 21 may be positioned, for example, above the lead screw 28 and above the rear of the handle 5.

[0138] An example is shown where a first central mechanism housing 13 and a second central mechanism housing 14 are sandwiched between the front mechanism housing 12 and the rear mechanism housing 15. Alternatively, a structure could be used where, for example, one or more central mechanism housings are sandwiched between them. An example is shown where the first central mechanism housing 13 and the second central mechanism housing 14 are made of cast aluminum. Alternatively, the first central mechanism housing 13 and the second central mechanism housing 14 could be made of lightweight materials such as cast magnesium.

[0139] An example is shown where a protrusion 31b protrudes radially outward from the side of the linear motion member 31, and grooves 32a and 32b that engage with the protrusion 31b are provided on the outer peripheral surface of the power conversion ring 32. Alternatively, for example, grooves may be provided on the side of the linear motion member 31, and a protrusion protruding radially outward from the outer peripheral surface of the power conversion ring 32 may be provided.

[0140] An example is shown of a tube expanding tool 1 equipped with an operating unit 44a that manually moves the terminal position sensor 42. Alternatively, a moving mechanism could be provided that automatically moves the terminal position sensor 42 based on a temperature sensor detecting the air temperature and the air temperature detected by the temperature sensor. As the moving mechanism, a motor or solenoid could be used, for example. An example is shown of a structure in which the main housing 11 supports the initial position sensor 41 and the terminal position sensor 42, and a magnet 43 is provided on the lead screw 28. Alternatively, a structure could be provided where, for example, the main housing 11 supports magnets at positions corresponding to the initial position sensor 41 and the terminal position sensor 42, and a Hall effect IC is provided on the lead screw 28.

[0141] An example is shown where a diameter expansion interval is set after the rotation interval of the gripper 4, but a rotation interval can also be set after the diameter expansion interval. An example is shown where the end time of the rotation interval is used as the time point for detecting a predetermined rotational speed of the electric motor 21 pre-stored in the controller 45. Alternatively, a structure can be provided with a sensor (Hall IC) for detecting the end time of the rotation interval between the initial position sensor 41 and the final position sensor 42 in the forward / backward direction.

[0142] An example is shown of a structure in which the wedge 3 is moved back and forth by a feed screw mechanism 25. Alternatively, the wedge 3 can be moved back and forth, for example, by a cam that is driven to rotate by an electric motor 21, and the initial angle and rotation angle of the cam and the rotational speed of the electric motor 21 can be detected to detect the rotation range and the diameter expansion range.

[0143] An example is shown of a feed screw mechanism 25 in which a ball 28b is clamped between the lead screw shaft 28 and the internal threaded component 27. Alternatively, a feed screw mechanism could be provided in which, for example, the lead screw shaft 28 and the internal threaded component 27 are directly screwed together without clamping the ball.

[0144] The number and front-to-back positions of the engaging recesses 52b of the initial positioning operation unit 54 and the engaging recesses 52c of the positioning terminal position operation unit 55 are not limited to the example shown and can be appropriately changed. The example shown shows a structure in which the engaging portion of the leaf spring and the ball of the positioning ball move in the vertical direction. Alternatively, a structure could be shown where, for example, the engaging portion of the leaf spring and the ball of the positioning ball move in the horizontal direction toward the sidewall of the slot 52a formed in the main body housing 52.

[0145] The initial position operation unit 72 may also replace the solenoid that moves the initial position sensor 41 in the back-and-forth direction and may be, for example, an electric motor. The terminal position operation unit 73 may also replace the solenoid that moves the terminal position sensor 42 in the back-and-forth direction and may be, for example, an electric motor.

[0146] The sensor positioning mechanism 53 using leaf springs 56 and 57, and the sensor positioning mechanism 61 using positioning beads 64 and 65 can also be applied to the pipe expanding tools 70, 80, and 90 that enable the initial position sensor 41 and the terminal position sensor 42 to move automatically.

[0147] Alternatively, instead of monitoring the bus current value with the expansion tool 90, when starting immediately after installing multiple grippers, the total rotational speed of the electric motor 21 from the initial position of the wedge 3 to the point where it begins to radially open the multiple grippers can be measured by the speed detection sensor 21d. The amount of movement of the lead screw 28 can be calculated based on the total rotational speed of the electric motor 21. Since the range where the wedge 3 has not expanded the multiple grippers can be determined based on the amount of movement of the lead screw 28, the initial position of the wedge 3 is set by moving the position of the initial position sensor 41 to reduce the range where it has not expanded.

Claims

1. A pipe expander for expanding the end diameter of a fluid pipe made of synthetic resin, characterized in that, have: An electric motor is housed within the main body casing; A lead screw shaft, which is parallel to the output shaft of the electric motor or is movable along its axis in the front-rear direction, is disposed in the main housing. An internally threaded component that engages with the lead screw shaft, causing the lead screw shaft to move back and forth by rotating about the axis of the lead screw shaft; A gear that transmits rotation of the output shaft of the electric motor by meshing with the internally threaded component; A wedge that extends forward from the lead screw axis; Multiple grippers are closably connected to the main body housing in such a way that they are pushed apart radially outward by the wedge as the wedge advances together with the lead screw shaft. An end cap that supports the plurality of grippers in a manner that allows them to be opened and closed and restricts the forward and backward movement of the plurality of grippers; The main body housing consists of a front mechanism housing, a central mechanism housing, and a rear mechanism housing, arranged sequentially from front to rear. as well as Bolts, which connect the front housing to the rear housing. The front mechanism housing engages with the end cap, restricting the end cap from moving forward. The rear housing restricts the rear end of the internally threaded component from moving rearward. The outer casing of the central mechanism is provided with a through hole for the bolt to pass through in the front-to-back direction.

2. The tube expander according to claim 1, characterized in that, It has a handle extending downward from the main body shell. The grip is positioned in the front-to-back direction between the electric motor and the plurality of grippers. The electric motor is positioned below the lead screw shaft.

3. The tube expander according to claim 2, characterized in that, At least a portion of the lead screw shaft overlaps with the grip in the front-to-back direction.

4. The tube expander according to any one of claims 1 to 3, characterized in that, A planetary reduction mechanism is provided between the output shaft of the electric motor and the lead screw shaft to reduce the output speed of the output shaft.

5. The tube expander according to any one of claims 1 to 3, characterized in that, It has: a rotary drive ring, which is connected to the rear of the plurality of grippers; as well as The gripper rotation mechanism, through the output of the electric motor, causes the rotary drive ring to rotate, thereby causing the multiple grippers to rotate circumferentially. The rotary drive ring is positioned in front of the internally threaded component.

6. The tube expander according to any one of claims 1 to 3, characterized in that, The front and rear mechanism housings are made of iron. The outer shell of the central mechanism is formed of a material that is lighter than iron.

7. The tube expander according to claim 6, characterized in that, A second central mechanism housing is located between the central mechanism housing and the rear mechanism housing. The front mechanism housing, the central mechanism housing, the second central mechanism housing, and the rear mechanism housing each have an engaging portion at each end that overlaps with each other in the front-rear direction for adjacent ends.

8. The tube expander according to claim 7, characterized in that, A main shaft that rotates integrally with the gear is provided in front of the output shaft. The central mechanism housing and the second central mechanism housing support the main shaft bearing that rotatably supports the main shaft and the internal thread component bearing that rotatably supports the internal thread component.

9. The tube expander according to claim 6, characterized in that, The rear mechanism housing supports the thrust bearing that abuts against the rear end of the internally threaded component.

10. The tube expander according to any one of claims 1 to 3, characterized in that, Ball bearings are clamped in the engagement portion of the lead screw shaft and the internal thread component.

11. The tube expander according to claim 1, characterized in that, It also features a controller that switches the output shaft of the electric motor to forward and reverse rotation. The lead screw is configured to move back and forth between an initial rear position and a final front position by rotating the internal thread component. The tube expanding tool has an initial position sensor or an end position sensor, or both, that sends a signal to the controller by detecting the lead screw shaft located at the initial position or the end position. The initial position sensor and / or the terminal position sensor are configured to move in the forward and backward direction, and the initial position and / or the terminal position of the lead screw shaft are variable according to the position of the initial position sensor and / or the terminal position sensor.

12. The tube expander according to claim 11, characterized in that, The initial position sensor and / or the terminal position sensor have a Hall IC disposed in the main body housing, and the lead screw is provided with a magnet.

13. The tube expander according to claim 11 or 12, characterized in that, The initial position sensor and / or the terminal position sensor have an operating part that protrudes outward from the main housing.

14. The tube expander according to claim 13, characterized in that, It has a handle extending downward from the main body shell. The operating part protrudes from the upper surface of the main body shell.

15. The tube expander according to claim 11 or 12, characterized in that, It has a gripper rotation mechanism that, through the output of the electric motor, causes multiple grippers to rotate circumferentially. The controller can supply current to the electric motor according to a first upper limit value and a second upper limit value of the current, wherein the first upper limit value of the current is the value of the current flowing in the electric motor in the rotation range of the plurality of grippers; and the second upper limit value of the current is the value of the current flowing in the electric motor in the expansion range of the plurality of grippers opening radially outward.

16. The tube expander according to claim 15, characterized in that, The device includes a speed detection sensor that detects the rotational speed of the electric motor and sends a signal to the controller. The controller sets the rotation range and the diameter expansion range based on the signal sent by the speed detection sensor and the detection signal that the lead screw has moved to the initial position or the terminal position.

17. The tube expander according to claim 15, characterized in that, The first upper limit value is set lower than the second upper limit value.

18. The tube expander according to claim 15, characterized in that, The rotation interval is the interval in which the wedge advances and precedes the diameter expansion interval.

19. The tube expander according to claim 15, characterized in that, The rotation interval is the interval after the wedge retraction and is located after the diameter expansion interval.

20. The tube expander according to claim 11 or 12, characterized in that, Ball bearings are clamped in the engagement portion of the lead screw shaft and the internal thread component.

21. The tube expander according to claim 11 or 12, characterized in that, It is possible to replace multiple said grippers and install multiple second grippers with different wall thicknesses in the radial direction than the multiple said grippers.

22. The tube expander according to claim 11 or 12, characterized in that, It has a sensor positioning mechanism that can retractably position the initial position sensor and / or the terminal position sensor at multiple positions in the forward and backward direction.

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