JP7707089B2 - Pipe expansion tool - Google Patents

Description

The present invention relates to a pipe expansion tool that expands the diameter of the end of a fluid pipe, for example made of synthetic resin, in order to connect it to a connected object.

For example, a fluid pipe made of PEX (Cross-linked polyethylene) may be connected to a connected object such as a metal pipe. A pipe expansion tool that expands the inside diameter of the end of a PEX pipe has been provided. The end of the PEX pipe is expanded using the pipe expansion tool and attached to the connected object. The end of the PEX pipe is reduced in diameter so that it gradually returns to its original diameter through elastic deformation. The PEX pipe with the reduced end is tightly connected to the connected object. The connected PEX pipe is held firmly to the connected object by utilizing its own elasticity.

Patent Document 1 describes a tube expansion tool that uses an electric motor as a drive source to expand the diameter of a PEX tube. The front part of the tube expansion tool is provided with a roughly conical wedge that advances or retreats relative to the end of the PEX tube, and multiple jaws that are aligned in the circumferential direction of the wedge in front of the wedge. The multiple jaws are pushed by the advancing wedge and open radially outward relative to each other. The end of the PEX tube can be expanded by opening the multiple jaws radially outward while inserted into the end opening of the PEX tube.

For example, if the tube expansion tool has six jaws, the end of the PEX tube receives a radially outward opening force from each of the jaws at six equally spaced locations in the circumferential direction. Therefore, in one expansion operation, the end of the PEX tube is expanded into a roughly hexagonal shape. To expand the end of the PEX tube into a circular shape, the expansion operation and a rotation operation in which the multiple jaws are rotated around the wedge at a specified angle (for example, 15° to 30°) are repeated alternately. This causes the position at which each jaw comes into contact with the inner surface of the PEX tube to move due to the rotation operation. Therefore, the end of the PEX tube is uniformly expanded and approaches a circular shape.

The pipe expanding tool has a wedge movement mechanism that moves the wedge back and forth to open and close the jaws, and a jaw rotation mechanism that rotates the jaws. As described in Patent Document 1, in conventional pipe expanding tools, the wedge movement mechanism is driven by the output of an electric motor, and the force that rotates the jaws is derived from the back and forth movement of the wedge. For this reason, it was necessary to place the jaw rotation mechanism downstream of the wedge movement mechanism on the power transmission path starting from the electric motor, which limited the freedom of placement. This made it difficult to provide a compact tool body.

US Patent No. 2020/0261959

Therefore, there is a need for a tube expansion tool that allows for a high degree of freedom in the arrangement of the mechanism that rotates the jaws in the circumferential direction of the wedge and is easy to use.

According to one feature of the present disclosure, a pipe expansion tool for expanding an end of a synthetic resin fluid pipe has an electric motor. The pipe expansion tool has a female thread member rotated by an electric motor. The pipe expansion tool has a screw shaft that is screwed into the female thread member and moves in the forward and backward directions by the rotation of the female thread member. The pipe expansion tool has a wedge extending forward from the screw shaft. The pipe expansion tool has a plurality of jaws that are pushed by the wedge when the wedge advances together with the screw shaft and open radially outward relative to each other. The pipe expansion tool has a rotary drive ring that is connected to the rear of the plurality of jaws. The pipe expansion tool has a spindle that is axially rotated by an electric motor to rotate the rotary drive ring. The pipe expansion tool has a linear movement member that is screwed into the spindle and moves linearly as the spindle rotates. The pipe expansion tool has a power conversion mechanism that is provided between the linear movement member and the rotary drive ring and converts the linear movement of the linear movement member into rotation of the rotary drive ring.

The rotation of the spindle is therefore converted into the linear movement of the linearly moving member. The linear movement of the linearly moving member is further converted into the rotation of the rotary drive ring. For this reason, a linearly moving member is interposed in the power transmission path between the spindle and the rotary drive ring. By interposing a linearly moving member, the components of the power transmission path have a higher degree of freedom in terms of arrangement compared to, for example, cases in which all components are provided as rotating members. This allows the tube expansion tool to be designed in a compact shape that is easy to use.

FIG. 1 is a perspective view of a tube expanding tool according to a first embodiment of the present disclosure. FIG. 2 is a perspective view of the tool body with a main body housing removed. FIG. 4 is a right side view of the tool body with the main body housing removed. FIG. FIG. 2 is a longitudinal sectional view of the tube expanding tool with the wedge in the initial position. FIG. 4 is a vertical cross-sectional view of the tool body when the rotation of the jaws has been completed. FIG. 4 is a vertical cross-sectional view of the tool body with the wedge in an end position. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5 . FIG. 13 is a view of the power conversion mechanism when viewed from below on the left side with the wedge in the initial position. FIG. 13 is a view of the power conversion mechanism when the rotation of the jaws has been completed, as viewed from below on the left side. FIG. 13 is a view of the power conversion mechanism when viewed from below on the left side with the wedge in an end position. FIG. FIG. 13 is a perspective view of a tube expanding tool according to a second embodiment of the present disclosure with the main body housing of the tool body removed. FIG. FIG. 4 is a vertical sectional view of the tool body with the wedge located at an initial position. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 15. This is a cross-sectional view taken along line XVII-XVII in Figure 16. FIG. 4 is a perspective view of a linear moving member and a power conversion ring. 17 is a view corresponding to the cross section taken along line XVII-XVII in FIG. 16, and is a vertical cross-sectional view of the tool body with the wedge positioned at its terminal position.

According to another feature of the present disclosure, the spindle extends parallel to the screw shaft. Therefore, by arranging the spindle along the screw shaft extending in the front-rear direction, the pipe expansion tool can be compactly installed in the up-down and left-right directions. In addition, the spindle and linear movement member can be installed so as not to interfere with the screw shaft that moves back and forth.

According to another feature of the present disclosure, the power conversion mechanism has a power conversion ring that can rotate coaxially with the rotary drive ring. The power conversion mechanism has a convex portion that protrudes from a first member of two members, the linear movement member and the power conversion ring, toward a second member. The power conversion mechanism has a groove in the second member that extends in the linear movement direction and in the circumferential direction and through which the convex portion is inserted. Therefore, the linear movement of the linear movement member can be converted into rotation of the power conversion ring with a simple engagement structure between the convex portion and the groove. This allows the power conversion mechanism to be provided in a compact manner. In addition, power transmission loss in the power conversion mechanism can be suppressed.

According to another feature of the present disclosure, a one-way clutch is provided between the power conversion ring and the rotary drive ring to restrict the rotational direction of the rotary drive ring to one direction. Therefore, the rotational direction of the jaws is restricted to one direction together with the rotary drive ring. Therefore, the position where each jaw comes into contact with the inner peripheral surface of the fluid pipe moves in one direction as the jaws rotate. This allows the end of the fluid pipe to be expanded into a uniform circle.

According to another feature of the present disclosure, the rotary drive ring is provided radially inward of the power conversion ring. A one-way clutch is provided radially between the power conversion ring and the rotary drive ring. Therefore, the power conversion ring, the one-way clutch, and the rotary drive ring can be accommodated with a short length in the front-rear direction. This allows the tube expansion tool to be made compact in the front-rear direction.

According to another feature of the present disclosure, the rotation drive ring and the power conversion ring are formed with insertion holes through which the wedge or screw shaft passes. Therefore, the rotation drive ring and the power conversion ring can be compactly arranged radially outward of the wedge or screw shaft. Moreover, the center of gravity of the pipe expansion tool can be brought closer to the axis of the screw shaft. This improves the weight balance of the pipe expansion tool and improves operability.

According to another feature of the present disclosure, the tube expansion tool is provided with rollers on the outer periphery of the convex portion. The rollers abut against the wall surface of the groove. Therefore, by providing the rollers, it is possible to reduce the power transmission loss when converting the linear movement of the linear movement member into the rotation of the power conversion ring.

According to another feature of the present disclosure, the tube expansion tool is provided with a rotation restriction portion that extends in the front-rear direction along the linear motion member and restricts the axial rotation of the linear motion member. Therefore, by restricting the rotation of the linear motion member, the conversion efficiency of converting the rotation of the spindle into the linear motion of the linear motion member can be increased.

According to another feature of the present disclosure, the power conversion ring is provided in front of the female threaded member. Therefore, the power conversion ring and the female threaded member can be arranged compactly in the vertical and horizontal directions. Therefore, the pipe expansion tool can be arranged compactly in the vertical and horizontal directions.

According to another feature of the present disclosure, balls are interposed in the screw-threaded portion between the screw shaft and the female screw member. Therefore, the balls interposed in the screw-threaded portion improve the efficiency of the transmission of the driving force. Therefore, the rotational drive of the female screw member relative to the screw shaft can be efficiently converted into forward and backward movement of the screw shaft.

According to another feature of the present disclosure, the pipe expansion tool has an upstream spindle that overlaps with the spindle in the fore-and-aft direction and is axially rotated by an electric motor. The axial rotation of the upstream spindle causes the female thread member and the spindle to rotate axially. Therefore, by overlapping the upstream spindle with the spindle in the fore-and-aft direction, the pipe expansion tool can be made even shorter in the fore-and-aft direction.

Next, one embodiment of the present disclosure will be described with reference to Figures 1 to 13. As shown in Figure 1, the pipe expansion tool 1 of this embodiment has a tool body 10 housed in a substantially cylindrical main housing 11, and a grip 5 extending downward from the center of the tool body 10 in the front-to-rear direction. A user is positioned approximately at the rear of the pipe expansion tool 1 (the far left side in Figure 1) and holds the grip 5. In the following description, the side in front of the user is referred to as the rear, and the side opposite the side in front of the user is referred to as the front. The user is used as the reference for the up, down, left, and right directions.

As shown in Figures 1 and 4, a ring-shaped cap 2 is attached to the front of the main housing 11. A roughly conical wedge 3 extending in the front-rear direction is provided inside the inner peripheral surface of the cap 2. The wedge 3 is attached to the front end of a cylindrical screw shaft 28 extending in the front-rear direction at the center of the main housing 11. The screw shaft 28 and the wedge 3 can move in the front-rear direction together. A plurality of jaws 4 extending in the front-rear direction are provided radially outward from the wedge 3 and radially inward from the cap 2. The plurality of jaws 4 are arranged at equal intervals in the circumferential direction of the wedge 3. For example, six jaws 4 are provided, and each jaw 4 is arranged at 60° intervals in the circumferential direction of the wedge 3. The plurality of jaws 4 can be opened and closed radially between a closed position in which they are in close contact with each other in the circumferential direction to cover the wedge 3, and an open position in which they open radially outward from each other to expose the tip of the wedge 3.

As shown in FIG. 1, a trigger-type switch lever 6 is provided on the front of the grip 5. A user can operate the switch lever 6 by pulling it while holding the grip 5. Inside the grip 5, a switch body 6a is provided, which is switched on and off in conjunction with the operation of the switch lever 6. The switch body 6a is in the off state when the switch lever 6 is not pulled, and is in the on state when the switch lever 6 is pulled. At the lower end of the grip 5, an approximately rectangular box-shaped expanded diameter section 7 that expands in the front-rear and left-right directions relative to the grip 5 is provided. The expanded diameter section 7 accommodates a controller 45. The controller 45 has a shallow rectangular box-shaped case and a control board that is housed in the case and molded with resin. The controller 45 is housed in the expanded diameter section 7 with its thickness direction (the direction in which the shortest side of the case extends) aligned with the up-down direction. The controller 45 mainly controls the drive of the electric motor 21, which will be described later.

As shown in FIG. 1, a battery mounting section 7a is provided on the underside of the enlarged diameter section 7, to which a rectangular box-shaped battery 8 can be removably attached. The battery 8 can be removed from the battery mounting section 7a by sliding it forward relative to the battery mounting section 7a. The battery 8 can be attached to the battery mounting section 7a by sliding it from the front to the rear of the battery mounting section 7a. The battery 8 can be removed from the battery mounting section 7a and repeatedly charged and used with a separately prepared charger. The battery 8 can be used as a power source for other electric tools. The battery 8 operates as a power source that supplies power to the electric motor 21.

As shown in FIG. 4, the main housing 11 accommodates the front mechanism housing 12, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 in this order from the front to the rear. The front mechanism housing 12, the first central mechanism housing 13, and the second central mechanism housing 14 are substantially cylindrical with a through hole in the center that penetrates in the front-rear direction. The rear mechanism housing 15 is provided in the form of a plate with the plate thickness direction being in the front-rear direction. The front mechanism housing 12, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 cooperate to form a mechanism housing that accommodates the spindle 24 and the female screw member 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.

As shown in Figures 2 and 4, a male thread 12a is provided on the outer peripheral surface of the front part of the front mechanism housing 12. A female thread 2b that screws into the male thread 12a is provided on the inner peripheral surface of the cap 2. By screwing the male thread 12a into the female thread 2b, the cap 2 is connected to the front part of the front mechanism housing 12. A rectangular protrusion 12c, which is a roughly rectangular plate-like protrusion that protrudes radially outward, is provided on the rear part of the front mechanism housing 12. Through holes 12e that penetrate in the front-rear direction are formed in the four corners of the rectangular protrusion 12c.

As shown in Figures 2 and 4, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 each have four bosses 13c, 14c, and 15c that protrude radially outward. Each boss 13c, 14c, and 15c is formed in a generally cylindrical shape that extends in the front-to-rear direction. A through hole 13f, 14f that penetrates in the front-to-rear direction is provided in the center of each boss 13c, 14c. A screw hole 15d that extends in the front-to-rear direction is provided in the center of each boss 15c.

As shown in Figures 2 and 4, by arranging the rectangular protrusion 12c and the bosses 13c, 14c, and 15c in the front-to-rear direction, the through holes 12e, 13f, and 14f and the screw holes 15d are connected in the front-to-rear direction. Four bolts 16 are inserted from front to rear through each of the connected through holes 12e, 13f, and 14f and fastened to the screw holes 15d. As a result, the front mechanism housing 12 and the rear mechanism housing 15 are connected by the bolts 16 with the first central mechanism housing 13 and the second central mechanism housing 14 sandwiched between them in the front-to-rear direction.

As shown in Figures 3 to 5, the rear end of the front mechanism housing 12 and the front end of the first central mechanism housing 13 are provided with approximately cylindrical engaging portions 12b and 13a, respectively. The inner circumferential surface of engaging portion 12b and the outer circumferential surface of engaging portion 13a have approximately the same diameter. Engaging portions 12b and 13a overlap in the front-to-rear direction and engage with each other in a so-called spigot structure in which the inner circumferential surface of engaging portion 12b and the outer circumferential surface of engaging portion 13a are in close contact with each other.

As shown in Figures 3 to 5, the rear end of the first central mechanism housing 13 and the front end of the second central mechanism housing 14 are provided with approximately cylindrical engaging portions 13b and 14a, respectively. The inner circumferential surface of engaging portion 13b and the outer circumferential surface of engaging portion 14a have approximately the same diameter. Engaging portions 13b and 14a overlap in the front-to-rear direction and engage with each other in a spigot structure in which the inner circumferential surface of engaging portion 13b and the outer circumferential surface of engaging portion 14a are in close contact with each other.

As shown in Figures 3 to 5, a generally cylindrical engagement portion 14b is provided at the rear end of the second central mechanism housing 14. A generally cylindrical engagement portion 15b that protrudes forward is provided at the front surface of the rear mechanism housing 15. The inner circumferential surface of engagement portion 14b and the outer circumferential surface of engagement portion 15b have generally the same diameter. Engagement portions 14b and 15b overlap in the front-to-rear direction and engage with each other in a spigot structure in which the inner circumferential surface of engagement portion 14b and the outer circumferential surface of engagement portion 15b are in close contact with each other.

As shown in Figures 1 and 5, a roughly cylindrical motor housing 20 that houses an electric motor 21 is provided at the rear of the main housing 11. The motor housing 20 is located below the screw shaft 28 and above the grip 5. For example, a motor called a DC brushless motor is used as the electric motor 21. The output shaft 21a of the electric motor 21 extends in the front-rear direction along the motor axis J and parallel to the screw shaft 28. The output shaft 21a is supported rotatably around the motor axis J by bearings 21e and 21f attached to the motor housing 20.

As shown in FIG. 5, the stator 21b of the electric motor 21 is supported non-rotatably on the inner peripheral surface of the motor housing 20. The rotor 21c of the electric motor 21 is attached to the output shaft 21a on the inner peripheral side of the stator 21b so as to be rotatable integrally with the output shaft 21a. A rotation speed detection sensor 21d is provided in front of the rotor 21c. The rotation speed detection sensor 21d detects the rotation angle of the rotor 21c to detect the rotation speed of the output shaft 21a. A fan 22 for introducing cooling air into the motor housing 20 is attached integrally to the output shaft 21a between the rotor 21c and the rear bearing 21f in the front-rear direction. 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.

As shown in FIG. 5, a planetary reduction mechanism 23 for reducing the output of the output shaft 21a is provided in front of the electric motor 21. The planetary reduction mechanism 23 is generally cylindrical with its center on the motor axis J and with approximately the same diameter as the electric motor 21. At the rear end of the planetary reduction mechanism 23, a first sun gear 23a is provided integrally with the front end of the output shaft 21a. A ring-shaped first internal gear 23b is provided radially outward of the first sun gear 23a and centered on the motor axis J. 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 carrier 23d in front of the first sun gear 23a. The rotational drive of the output shaft 21a is transmitted to the first carrier 23d at a reduced speed via the first sun gear 23a and the first planetary gear 23c.

As shown in FIG. 5, the first carrier 23d is integral with the second sun gear 23e in front and can rotate together with the second sun gear 23e around the motor axis J. A ring-shaped second internal gear 23f is provided radially outward of the second sun gear 23e and is centered on the motor axis J. A plurality of 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 a second carrier 23h disposed in front of the second sun gear 23e. The second carrier 23h is integral with the spindle 24 in front and can rotate around the motor axis J. Therefore, the rotational drive of the first carrier 23d is transmitted to the spindle 24 at a reduced speed via the second sun gear 23e, the second planetary gears 23g, and the second carrier 23h. Thus, the rotational drive of the output shaft 21a is transmitted at a reduced speed to the spindle 24 via the planetary reduction mechanism 23.

As shown in FIG. 5, the spindle 24 is supported by spindle bearings 24b and 24c so as to be rotatable about the motor axis J. The front spindle bearing 24b is press-fitted into a recess 13d recessed in the lower part of the first central mechanism housing 13. The rear spindle bearing 24c is press-fitted into a recess 14d recessed in the lower part of the second central mechanism housing 14. The spindle bearings 24b and 24c are accommodated in a space formed by the cooperation of the first central mechanism housing 13 and the second central mechanism housing 14. A gear 26 for transmitting power to the screw shaft 28 is provided on the spindle 24 so as to be rotatable integrally therewith. The gear 26 is provided between the front and rear of the spindle bearings 24b and 24c. A male thread 24a is formed on the outer peripheral surface of the spindle 24 in front of the spindle bearing 24b.

As shown in Figures 4 and 5, the tool body 10 is provided with a feed screw mechanism 25, also known as a ball screw mechanism. The feed screw mechanism 25 has a screw shaft 28, a female screw member 27, and a gear 26. The screw shaft 28 is arranged on the screw shaft axis K extending in the front-rear direction at the center of the main body housing 11. The screw shaft 28 can move in the front-rear direction along the screw shaft axis K. When the screw shaft 28 is located at the rear end of its moving range, it overlaps with the output shaft 21a in the front-rear direction. The female screw member 27 is formed in a substantially cylindrical shape that screws with the screw shaft 28 and meshes with the gear 26. A female screw 27b is provided on the inner peripheral surface of the female screw member 27. The female screw 27b is screwed into the male screw 28a of the screw shaft 28 via a plurality of balls 28b between the female screw member 27 and the male screw 28a. A gear 27a that protrudes radially outward and meshes with the gear 26 is provided in the center of the female screw member 27 in the front-rear direction. The rotational drive of the spindle 24 is transmitted at a reduced speed to the female thread member 27 by the meshing of the gear 27a and the gear 26.

As shown in Figures 4 and 5, the female screw member 27 is supported by front and rear female screw member bearings 27c and 27d to be rotatable around the screw shaft axis K. The female screw member bearing 27c in front of the gear 27a is pressed into the inner peripheral surface 13e of the first central mechanism housing 13. The female screw member bearing 27d in the rear of the gear 27a is pressed into the inner peripheral surface 14e of the second central mechanism housing 14. The female screw member bearings 27c and 27d are accommodated in a space formed by the cooperation 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 female screw member 27 and the front surface 15a of the rear mechanism housing 15 to receive a thrust load that pushes the female screw member 27 rearward. A washer 27f is provided between the front surface of the female screw member 27 and the rear surface of the power conversion ring 32 described later.

As shown in Figures 2 and 3, a screw shaft guide 29 is provided at the rear of the screw shaft 28 to guide the forward and backward movement of the screw shaft 28 relative to the main housing 11. The screw shaft guide 29 has a support member 29a that is connected to the screw shaft 28 and extends in the left-right direction, and rollers 29b provided at both left and right ends of the support member 29a. A pair of loop-shaped rails 29c that extend in the front-back direction are provided on the left and right inner peripheral surfaces of the main housing 11. The rollers 29b engage with the rails 29c and are movable in the front-back direction along the rails 29c. The screw shaft 28 is guided by the rollers 29b and is movable in the front-back direction.

As shown in Figures 4 and 5, the tool body 10 is provided with a power conversion mechanism 30 that rotates the multiple jaws 4. The power conversion mechanism 30 has a linear movement member 31 and a power conversion ring 32. The linear movement member 31 is formed in an approximately cylindrical shape with the front-rear direction as the axial direction. The linear movement member 31 has a female thread 31a provided on the inner circumferential surface and a columnar convex portion 31b extending perpendicular to the axial direction of the approximately cylindrical shape. A roller 31c that covers the convex portion 31b in the circumferential direction and can rotate around the axis of the convex portion 31b is provided at the upper end of the convex portion 31b. The female thread 31a of the linear movement member 31 is screwed into the male thread 24a of the spindle 24. A rotation restriction portion 12d that restricts the rotation of the linear movement member 31 is provided at the bottom of the front mechanism housing 12. The rotation restriction portion 12d is formed in a groove shape that penetrates the front mechanism housing 12 in the radial direction and extends linearly in the front-rear direction.

As shown in Figs. 4 and 9, the power conversion ring 32 is substantially cylindrical with an insertion hole 32d at the center that penetrates in the front-rear direction. Grooves 32a and 32b are recessed in the outer peripheral surface of the lower part of the power conversion ring 32. The groove 32a extends in the circumferential direction of the power conversion ring 32, for example, in a direction that intersects with the axial direction (front-rear direction) of the power conversion ring 32 at an inclination angle of 45°. The inclination direction of the groove 32a is counterclockwise toward the front when viewed from the front side. The groove 32b extends parallel to the axial direction of the power conversion ring 32. The convex portion 31b with the roller 31c attached is inserted into the grooves 32a and 32b. The front end of the groove 32a and the rear end of the groove 32b are connected so that the convex portion 31b can move smoothly.

As shown in Figures 5 to 8, the power conversion ring 32 is housed in the front mechanism housing 12. The linear movement member 31 is screwed onto the male thread 24a of the spindle 24 below the front mechanism housing 12. The convex portion 31b extends upward through the rotation restriction portion 12d and is inserted into the groove 32a or groove 32b. The roller 31c abuts against both the wall surfaces of the grooves 32a and 32b and the wall surface of the rotation restriction portion 12d. The rotation of the linear movement member 31 around the axis of the spindle 24 is restricted by the engagement between the convex portion 31b and the rotation restriction portion 12d.

As shown in Figures 10 to 12, when the spindle 24 rotates around its axis, the linear movement member 31 moves in the front-rear direction due to the engagement of the male screw 24a and the female screw 31a and the restriction of the rotation of the linear movement member 31 around its axis. When the linear movement member 31 is located at the rear end of its movement range, the convex portion 31b is located at the rear end of the groove 32a. When the linear movement member 31 moves forward from the rear end, the convex portion 31b moves forward within the groove 32a. Because the rotation of the linear movement member 31 is restricted, the convex portion 31b does not move in the left-right direction. Therefore, the advancing convex portion 31b presses the wall surface of the groove 32a. As a result, the power conversion ring 32 rotates in the clockwise direction as viewed from the front side around the screw shaft axis K. When the linear movement member 31 moves further forward, the convex portion 31b enters the groove 32b from the groove 32a. Because the groove 32b is not inclined with respect to the front-rear direction, no force is generated that causes the convex portion 31b to press the wall surface of the groove 32b. Therefore, the power conversion ring 32 does not rotate.

As shown in Figures 10 to 12, when the linear moving member 31 moves rearward from the front end of its range of movement, the convex portion 31b first moves within the groove 32b. At this time, no force is generated that pushes the convex portion 31b against the wall of the groove 32b, so the power conversion ring 32 does not rotate. When the convex portion 31b moves rearward within the groove 32a, the convex portion 31b pushes against the wall of the groove 32a, causing the power conversion ring 32 to rotate counterclockwise when viewed from the front.

As shown in Figures 4 and 5, a cylindrical one-way clutch 33 and a substantially cylindrical first rotation drive ring 34 are provided radially inward of the power conversion ring 32. The one-way clutch 33 is attached to the inner peripheral surface of the power conversion ring 32. The first rotation drive ring 34 is disposed radially inward of the one-way clutch 33 and radially outward of the screw shaft 28. The one-way clutch 33 allows only clockwise rotation drive as viewed from the front side, and transmits it from the power conversion ring 32 to the first rotation drive ring 34. On the other hand, counterclockwise rotation drive as viewed from the front side is not transmitted from the power conversion ring 32 to the first rotation drive ring 34 via the one-way clutch 33.

As shown in Figures 4 and 5, the first rotation drive ring 34 is generally cylindrical with a through hole 34d in the center that penetrates in the front-rear direction. The screw shaft 28 is inserted into the through hole 34d so as to be movable in the front-rear direction. The first rotation drive ring 34 has a small diameter portion 34a and a large diameter portion 34b that are cylindrical and centered on the screw shaft axis K. The small diameter portion 34a is disposed behind the large diameter portion 34b. The small diameter portion 34a is press-fitted into the inner peripheral surface of the one-way clutch 33. The outer peripheral surface of the large diameter portion 34b is provided with a plurality of recessed grooves 34c that extend in the front-rear direction. The plurality of recessed grooves 34c are disposed at a predetermined interval in the circumferential direction, for example, at 90° intervals in the circumferential direction of the large diameter portion 34b.

As shown in Figures 4 and 5, the second rotation drive ring 35 that engages with the first rotation drive ring 34 is provided in front of the first rotation drive ring 34. The second rotation drive ring 35 is substantially cylindrical with a through hole 35e in the center that penetrates in the front-rear direction. The screw shaft 28 and the first rotation drive ring 34 are inserted into the through hole 35e. The inner peripheral surface of the second rotation drive ring 35 is provided with a plurality of engaging protrusions 35a that protrude radially inward. By inserting the first rotation drive ring 34 into the through hole 35e, the multiple engaging protrusions 35a engage with the multiple recessed grooves 34c. Therefore, the second rotation drive ring 35 can rotate together with the first rotation drive ring 34 around the screw shaft axis K, and can slide in the front-rear direction relative to the first rotation drive ring 34.

As shown in Figures 4 and 5, a spring bearing 35d that protrudes radially outward is provided at the front of the outer circumferential surface of the second rotation 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 interposed between the spring bearing 35d and the washer 32c. The second rotation drive ring 35 is biased forward by the compression spring 35c. A plurality of meshing teeth 35b with a shape in which protrusions and recesses in the front-rear direction are repeated in the circumferential direction are provided at the front surface of the second rotation drive ring 35.

As shown in Figures 4 and 5, a third rotation drive ring 36 that engages with the second rotation drive ring 35 and the multiple jaws 4 is provided in front of the second rotation drive ring 35. The third rotation drive ring 36 is substantially cylindrical with a through hole 36c penetrating in the front-rear direction at the center. The screw shaft 28 is inserted into the through hole 36c. A plurality of meshing teeth 36a having a shape in which the front-rear concaves and convexes are repeated in the circumferential direction are provided on the rear surface of the third rotation drive ring 36. The meshing teeth 36a engage with the meshing teeth 35b of the second rotation drive ring 35. The third rotation drive ring 36 can rotate integrally with the second rotation drive ring 35 around the screw shaft axis K by the meshing of the meshing teeth 35b and the meshing teeth 36a. A plurality of engagement protrusions 36b protruding forward are provided on the front end surface of the third rotation drive ring 36. Each engaging protrusion 36b engages with an engaging recess 4b (see FIG. 13) provided on the rear end surface of the jaw 4. This allows the multiple jaws 4 to rotate integrally with the third rotation drive ring 36 around the screw shaft axis K.

For example, the jaws 4 may bite into the inner circumferential surface of the fluid pipe. In this case, the second rotation drive ring 35 moves back against the biasing force of the compression spring 35c and moves away from the third rotation drive ring 36. This disengages the meshing teeth 35b and 36a. Therefore, the power transmission path for rotating the multiple jaws 4 around the screw shaft axis K is cut off between the second rotation drive ring 35 and the third rotation drive ring 36. This prevents the jaws 4 that are biting into the fluid pipe from being subjected to an excessive load due to the rotation drive, and prevents damage to each component (e.g., the linear motion member 31 that transmits the power, the power conversion ring 32, and the rotation drive rings 34, 35, and 36).

As shown in Figures 5 to 7, a ring housing groove 4a with an arc-shaped cross section is provided on the radial outer periphery of the rear part of the jaw 4. The ring housing grooves 4a of the multiple jaws 4 are connected in the circumferential direction to form an annular groove. The multiple jaws 4 are connected in the circumferential direction by a ring 4c that is inserted into the ring housing groove 4a and can expand and contract elastically. A jaw support groove 2a that can accommodate the ring 4c is provided on the inner peripheral surface of the cap 2, extending radially outward and in the circumferential direction. The jaw support groove 2a allows the ring 4c to move in the radial direction, but restricts the ring 4c from moving forward and backward. The multiple jaws 4 open and close radially around the ring 4c supported by the jaw support groove 2a.

The drive of the feed screw mechanism 25 and the power conversion mechanism 30 will be described with reference to Figures 5 to 7 and 10 to 12. First, the output shaft 21a of the electric motor 21 rotates. The rotational drive of the output shaft 21a is decelerated by the planetary reduction mechanism 23 and transmitted to the spindle 24. When the spindle 24 rotates, the female screw member 27 rotates due to the meshing of the gear 26 and the gear 27a. In addition, the linear movement member 31 moves in the front-rear direction due to the screwing of the male screw 24a and the female screw 31a and the restriction of the rotation of the linear movement member 31 by the rotation restriction part 12d. When the female screw member 27 rotates, the screw shaft 28 moves in the front-rear direction due to the screwing of the female screw 27b and the male screw 28a. When the screw shaft 28 advances, the wedge 3 attached to the front end of the screw shaft 28 presses the multiple jaws 4 and the ring 4c to move radially outward to an open position. When the screw shaft 28 retracts, the pressing force of the wedge 3 is released, causing the ring 4c to contract and the multiple jaws 4 to return to their closed position radially inward.

When the linearly moving member 31 advances and the convex portion 31b advances in the groove 32a, the power conversion ring 32 rotates in a clockwise direction as viewed from the front side. The rotational drive of the power conversion ring 32 is transmitted to the first rotation drive ring 34 via the one-way clutch 33. The first rotation drive ring 34, the second rotation drive ring 35, and the third rotation drive ring 36 rotate in a clockwise direction as viewed from the front side. Therefore, the multiple jaws 4 supported by the third rotation drive ring 36 also rotate in a clockwise direction as viewed from the front side. When the convex portion 31b advances in the groove 32b, the power conversion ring 32 does not rotate. Therefore, the first rotation drive ring 34, the second rotation drive ring 35, the third rotation drive ring 36, and the multiple jaws 4 do not rotate.

When the linearly moving member 31 retreats and the convex portion 31b retreats within the groove 32b, the power conversion ring 32 does not rotate. Therefore, the first rotation drive ring 34, the second rotation drive ring 35, the third rotation drive ring 36, and the multiple jaws 4 do not rotate. When the convex portion 31b retreats within the groove 32a, the power conversion ring 32 rotates in a counterclockwise direction as viewed from the front. The one-way clutch 33 transmits only the rotation drive in the clockwise direction as viewed from the front to the first rotation drive ring 34. Therefore, the first rotation drive ring 34, the second rotation drive ring 35, the third rotation drive ring 36, and the multiple jaws 4 do not rotate.

The electric motor 21 is switched between forward and reverse rotation by the controller 45 (see FIG. 1). When the electric motor 21 rotates forward, the multiple jaws 4 are pushed by the advancing wedge 3 and open radially outward relative to each other. When the electric motor 21 rotates forward, the multiple jaws 4 are rotated clockwise as viewed from the front by the power conversion mechanism 30. When the electric motor 21 rotates reversely, the multiple jaws 4 close radially inward relative to each other as the wedge 3 retreats. When the electric motor 21 rotates reversely, the multiple jaws 4 do not rotate due to the rotation restriction of the one-way clutch 33.

The timing of the rotation of the multiple jaws 4 by the power conversion mechanism 30 and the opening and closing of the multiple jaws 4 by the back and forth movement of the wedge 3 by the feed screw mechanism 25 can be changed by the design of each mechanism. For example, the timing of the operation can be changed by changing the shape of the grooves 32a and 32b provided in the power conversion ring 32, the range of movement of the screw shaft 28 in the back and forth direction, etc. In this embodiment, the multiple jaws 4 are set to open and close immediately after the rotation of the multiple jaws 4 is completed.

As shown in Figures 3 and 5, an end position sensor 42 is provided behind the female screw member 27 to detect when the screw shaft 28 has moved to the end position at the front end of its range of movement. An initial position sensor 41 is provided behind the end position sensor 42 to detect when the screw shaft 28 has moved to the initial position at the rear end of its range of movement. The initial position sensor 41 and the end position sensor 42 are sensors that detect magnetic fields and are called Hall ICs. The initial position sensor 41 is fixed to the main housing 11 above the screw shaft 28. The end position sensor 42 is supported by the main housing 11 above the screw shaft 28 so that it can move back and forth.

As shown in Figs. 1 and 5, a position adjustment mechanism 44 that allows the terminal position sensor 42 to move in the front-rear direction is provided on the upper part of the main housing 11. A slot 11a is provided on the upper surface of the main housing 11, which penetrates the main housing 11 in the vertical direction and extends linearly in the front-rear direction. The position adjustment mechanism 44 has an operating part 44a that penetrates the slot 11a and is exposed from the upper surface of the main housing 11. The terminal position sensor 42 is supported on the lower end of the operating part 44a inside the main housing 11. The terminal position sensor 42 can slide in the front-rear direction along the slot 11a together with the operating part 44a. The front-rear position of the terminal position sensor 42 can be changed by sliding the operating part 44a with the user's finger.

As shown in Figures 3 and 5, a magnet 43 is attached to the upper rear side of the screw shaft 28. The initial position sensor 41 detects the position of the screw shaft 28 and the wedge 3 when they overlap the magnet 43 in the front-rear direction as the initial position. The terminal position sensor 42 detects the position of the screw shaft 28 and the wedge 3 when they overlap the magnet 43 in the front-rear direction as the terminal position.

As described above, the pipe expansion tool 1 for expanding the end of a synthetic resin fluid pipe has an electric motor 21 as shown in Figures 5 to 7. The pipe expansion tool 1 has a female threaded member 27 rotated by the electric motor 21. The pipe expansion tool 1 has a screw shaft 28 that screws into the female threaded member 27 and moves in the forward and backward directions by the rotation of the female threaded member 27. The pipe expansion tool 1 has a wedge 3 extending forward from the screw shaft 28. The pipe expansion tool 1 has multiple jaws 4 that are pushed by the wedge 3 when the wedge 3 advances together with the screw shaft 28 and open radially outward relative to each other. The pipe expansion tool 1 has rotary drive rings 34, 35, and 36 that are connected to the rear of the multiple jaws 4. The pipe expansion tool 1 has a spindle 24 that is axially rotated by the electric motor 21 to rotate the rotary drive rings 34, 35, and 36. The tube expansion tool 1 has a linear movement member 31 that is screwed onto the spindle 24 and moves linearly as the spindle 24 rotates around its axis. The tube expansion tool 1 has a power conversion mechanism 30 that is provided between the linear movement member 31 and the rotary drive rings 34, 35, and 36 and converts the linear movement of the linear movement member 31 into the rotation of the rotary drive rings.

The rotation of the spindle 24 is therefore converted into the linear movement of the linear movement member 31. Furthermore, the linear movement of the linear movement member 31 is converted into the rotation of the rotary drive rings 34, 35, and 36. For this reason, the linear movement member 31 is interposed in the power transmission path between the spindle 24 and the rotary drive rings 34, 35, and 36. By interposing the linear movement member 31, the components of the power transmission path have a higher degree of freedom in terms of arrangement compared to, for example, a case in which all components are provided as rotating members. Therefore, the pipe expansion tool 1 can be designed into a compact shape that is easy to use.

As shown in FIG. 5, the spindle 24 extends parallel to the screw shaft 28. Therefore, by arranging the spindle 24 along the screw shaft 28 extending in the front-rear direction, the pipe expansion tool 1 can be compactly arranged in the vertical and horizontal directions. In addition, the spindle 24 and the linear movement member 31 can be arranged so as not to interfere with the screw shaft 28 that moves back and forth.

As shown in Figures 4 to 7, the power conversion mechanism 30 has a power conversion ring 32 that can rotate on the screw shaft axis K that is coaxial with the rotary drive rings 34, 35, and 36. The power conversion mechanism 30 has a convex portion 31b that protrudes from the linear movement member 31 toward the power conversion ring 32. The power conversion mechanism 30 has grooves 32a and 32b in the power conversion ring 32 that extend in the linear movement direction and the circumferential direction and through which the convex portion 31b is inserted. Therefore, the linear movement of the linear movement member 31 can be converted into the rotation of the power conversion ring 32 with a simple engagement structure between the convex portion 31b and the grooves 32a and 32b. This allows the power conversion mechanism 30 to be provided in a compact manner. In addition, the power transmission loss in the power conversion mechanism 30 can be suppressed.

As shown in FIG. 5, a one-way clutch 33 is provided between the power conversion ring 32 and the rotation drive rings 34, 35, 36 to restrict the rotation direction of the rotation drive rings 34, 35, 36 to one direction. Therefore, the rotation direction of the jaws 4 is restricted to one direction together with the rotation drive rings 34, 35, 36. Therefore, the position where each jaw 4 comes into contact with the inner surface of the fluid pipe moves in one direction as the jaws 4 rotate. This allows the end of the fluid pipe to be expanded into a uniform circle.

As shown in Figures 5 and 8, the first rotary drive ring 34 is provided radially inward of the power conversion ring 32. The one-way clutch 33 is provided radially between the power conversion ring 32 and the first rotary drive ring 34. Therefore, the power conversion ring 32, the one-way clutch 33, and the first rotary drive ring 34 can be accommodated with a short length in the front-rear direction. This allows the tube expansion tool 1 to be made compact in the front-rear direction.

As shown in Figures 4 and 5, the rotational drive rings 34, 35, 36 and the power conversion ring 32 are formed with insertion holes 34d, 35e, 36c, 32d through which the wedge 3 or the screw shaft 28 passes. Therefore, the rotational drive rings 34, 35, 36 and the power conversion ring 32 can be compactly arranged radially outward of the wedge 3 or the screw shaft 28. Moreover, the center of gravity of the pipe expansion tool 1 can be brought closer to the screw shaft axis K. This improves the weight balance of the pipe expansion tool 1 and improves operability.

As shown in Figures 5 to 8, the tube expansion tool 1 is provided with rollers 31c on the outer periphery of the protrusion 31b. The rollers 31c abut against the wall surfaces of the grooves 32a and 32b. Therefore, by providing the rollers 31c, it is possible to reduce the power transmission loss when converting the linear movement of the linear movement member 31 into the rotation of the power conversion ring 32.

As shown in Figures 5 to 8, the tube expansion tool 1 is provided with a rotation restriction portion 12d that extends in the front-rear direction along the linear motion member 31 and restricts the axial rotation of the linear motion member 31. Therefore, by restricting the rotation of the linear motion member 31, the conversion efficiency of converting the rotation of the spindle 24 into the linear motion of the linear motion member 31 can be increased.

As shown in FIG. 5, the power conversion ring 32 is provided in front of the female thread member 27. Therefore, the power conversion ring 32 and the female thread member 27 can be arranged compactly in the vertical and horizontal directions. Therefore, the pipe expansion tool 1 can be arranged compactly in the vertical and horizontal directions.

As shown in FIG. 5, balls 28b are interposed in the screwed portion between the screw shaft 28 and the female screw member 27. Therefore, the balls 28b interposed in the screwed portion improve the transmission efficiency of the driving force. Therefore, the rotational drive of the female screw member 27 relative to the screw shaft 28 can be efficiently converted into forward and backward movement of the screw shaft 28.

Next, a second embodiment of the present disclosure will be described with reference to Figures 14 to 19. The pipe expansion tool 50 of the second embodiment has a feed screw mechanism 60 and a power conversion mechanism 70 instead of the feed screw mechanism 25 and the power conversion mechanism 30 of the pipe expansion tool 1 of the first embodiment shown in Figure 5. The tool body 51 of the pipe expansion tool 50 accommodates the front mechanism housing 52, the first central mechanism housing 53, the second central mechanism housing 54, the third central mechanism housing 55, and the rear mechanism housing 56 in this order from the front to the rear. The front mechanism housing 52, the first central mechanism housing 53, the second central mechanism housing 54, and the third central mechanism housing 55 are substantially cylindrical with through holes penetrating in the front-to-rear direction. The rear mechanism housing 56 is formed in a plate shape with the plate thickness direction being in the front-to-rear direction. The front mechanism housing 52 and the rear mechanism housing 56 are made of iron. The first central mechanism housing 53, the second central mechanism housing 54, and the third central mechanism housing 55 are made of aluminum.

As shown in Figures 14 and 15, the front mechanism housing 52 is provided behind the cap 2. The front outer peripheral surface of the front mechanism housing 52 is provided with a male thread 52a that screws into the female thread 2b of the cap 2. The front mechanism housing 52, the first central mechanism housing 53, the second central mechanism housing 54, and the third central mechanism housing 55 each have four bosses 52c, 53c, 54c, and 55c that are approximately cylindrical and extend radially outward. A through hole that penetrates in the front-rear direction is formed in the center of each boss 52c, 53c, 54c, and 55c. The rear mechanism housing 56 has four bosses 56c that extend radially outward. A screw hole that extends in the front-rear direction is provided in the center of each boss 56c. The bosses 52c, 53c, 54c, 55c, and 56c are arranged in the front-rear direction to communicate the through hole and the screw hole in the front-rear direction. Four bolts 57 are inserted from front to rear through each of the connected through holes and fastened to the screw holes in the rear mechanism housing 56. As a result, the front mechanism housing 52 and the rear mechanism housing 56 are connected by the bolts 57 with the first central mechanism housing 53, the second central mechanism housing 54, and the third central mechanism housing 55 sandwiched between them in the front-to-rear direction.

As shown in FIG. 15, a substantially cylindrical engaging portion 52b is provided at the rear end of the front mechanism housing 52. A substantially cylindrical engaging portion 53a having substantially the same outer diameter as the inner peripheral surface of the engaging portion 52b is provided at the front end of the first central mechanism housing 53. A substantially cylindrical engaging portion 53b is provided at the rear end of the first central mechanism housing 53. A substantially cylindrical engaging portion 54a having substantially the same outer diameter as the inner peripheral surface of the engaging portion 53b is provided at the front end of the second central mechanism housing 54. A substantially cylindrical engaging portion 54b is provided at the rear end of the second central mechanism housing 54. A substantially cylindrical engaging portion 55a having substantially the same outer diameter as the inner peripheral surface of the engaging portion 54b is provided at the front end of the third central mechanism housing 55. Engagement parts 52b and 53a, engagement parts 53b and 54a, and engagement parts 54b and 55a overlap in the front-rear direction, respectively, and engage with each other in a spigot structure in which the inner circumferential surfaces of engagement parts 52b, 53b, and 54b are in close contact with the outer circumferential surfaces of engagement parts 53a, 54a, and 55a.

As shown in FIG. 15, an upstream spindle 61 is attached integrally to the front of the second carrier 23h of the planetary reduction mechanism 23. The upstream spindle 61 is supported by spindle bearings 61a and 61b so as to be rotatable about the motor axis J. The front spindle bearing 61a is pressed into a recess 54d recessed in the lower part of the second central mechanism housing 54. The rear spindle bearing 61b is pressed into a hole 56d penetrating the lower part of the rear mechanism housing 56 in the front-rear direction. A gear 62 for transmitting power to the screw shaft 28 and a gear 63 for transmitting power to the power conversion mechanism 70 (see FIG. 16) are attached integrally to the upstream spindle 61 so as to be rotatable integrally. The gears 62 and 63 are provided between the front and rear spindle bearings 61a and 61b. The gear 63 is provided rearward of the gear 62.

As shown in FIG. 15, the tool body 51 is provided with a feed screw mechanism 60, also known as a ball screw mechanism. The feed screw mechanism 60 has a screw shaft 28, a female screw member 27, and a gear 62. The gear 27a of the female screw member 27 meshes with the gear 62 and rotates about the screw shaft axis K by the rotational drive of the upstream spindle 61. The front female screw member bearing 27c, which rotatably supports the female screw member 27, is pressed into the inner peripheral surface 54e of the second central mechanism housing 54. The rear female screw member bearing 27d is pressed into the inner peripheral surface 55d of the third central mechanism housing 55. The thrust bearing 27e is interposed between the female screw member 27 and the rear mechanism housing 56 in the front-rear direction.

As shown in Figures 17 and 19, the tool body 51 is provided with a spindle 64 having a substantially cylindrical shape. The spindle 64 is disposed on a spindle axis P extending in the front-rear direction. The spindle axis P is located to the lower left of the screw shaft axis K and to the upper left of the motor axis J (see Figure 16). A gear 65 protruding radially outward is integrally provided on the outer periphery of the spindle 64. The gear 65 meshes with a gear 62 (see Figure 15) attached to the upstream spindle 61. The output of the electric motor 21 is transmitted through the upstream spindle 61 to rotate the spindle 64 around its axis. The rear part of the spindle 64 is rotatably supported by a spindle bearing 64b. The spindle bearing 64b is press-fitted into a hole 56e penetrating the lower part of the rear mechanism housing 56 in the front-rear direction. A female thread 64a is formed on the inner circumferential surface of the spindle 64. A linear movement member 71 (described later) is screwed into the female thread 64a. The front part of the spindle 64 is supported by the screwed linear movement member 71.

As shown in Figures 17 and 19, the tool body 51 is provided with a power conversion mechanism 70 that converts the output of the electric motor 21 into a driving force for rotating the multiple jaws 4. The power conversion mechanism 70 has a linear movement member 71 and a power conversion ring 72. The linear movement member 71 and the power conversion ring 72 are disposed in front of the spindle 64 on the spindle axis P.

As shown in Figures 17 to 19, the linear movement member 71 has a male screw 71a formed on the outer periphery of a cylindrical shaft portion, and a sliding portion 71b formed in a cylindrical shape with a larger diameter than the male screw 71a in front of the male screw 71a. The male screw 71a is screwed into the female screw 64a of the spindle 64. The sliding portion 71b is provided with an attachment hole 71c penetrating in the vertical direction. A cylindrical convex portion 71d is attached to the attachment hole 71c in a state where it protrudes both upward and downward. A roller 71e is provided at the lower end of the convex portion 71d, which covers the convex portion 71d in the circumferential direction and can rotate around the axis of the convex portion 71d. A groove-shaped rotation restriction portion 54f is provided at the bottom of the second central mechanism housing 54, which penetrates the second central mechanism housing 54 in the radial direction and extends linearly in the front-rear direction. The roller 71e is attached to the rotation restriction portion 54f so as to be movable in the front-rear direction. The linear movement member 71 is restricted from rotating around the spindle axis P by the engagement between the roller 71e and the rotation restriction portion 54f.

As shown in Figures 17 to 19, the power conversion ring 72 has a cylindrical shaft portion 72c provided at the front and a ring portion 72e of a substantially cylindrical shape provided behind the shaft portion 72c. Grooves 72a and 72b are provided on the outer circumferential surface of the ring portion 72e, penetrating in the radial direction. The groove 72a extends in the circumferential direction of the power conversion ring 72, for example, in a direction intersecting the axial direction (front-rear direction) of the power conversion ring 72 at an inclination angle of 45°. The inclination direction of the groove 72a is a clockwise direction toward the front when viewed from the front side. The groove 72b extends parallel to the axial direction of the power conversion ring 72. The convex portion 71d of the linear movement member 71 is inserted into the groove 72a or the groove 72b. The front end of the groove 72a and the rear end of the groove 72b are connected so that the convex portion 71d can move smoothly. The front end of the shaft portion 72c is rotatably supported by the bearing 72d. The bearing 72d is press-fitted into a recess 53d recessed into the bottom of the first central mechanism housing 53.

17 and 19, when the spindle 64 rotates around its axis, the linear movement member 71 moves in the front-rear direction due to the engagement of the female screw 64a and the male screw 71a and the restriction of the rotation of the linear movement member 71 around its axis. When the linear movement member 71 moves forward from the rear end of its movement range, the convex portion 71d moves forward in the groove 72a. The convex portion 71d does not move in the left-right direction due to the restriction of rotation, so it presses against the wall of the groove 72a. Therefore, the power conversion ring 72 rotates counterclockwise around the spindle axis P as viewed from the front. When the linear movement member 71 moves further forward, the convex portion 71d enters the groove 72b from the groove 72a. Since the groove 72b is not inclined with respect to the front-rear direction, no force is generated that causes the convex portion 71d to press against the wall of the groove 72b. Therefore, the power conversion ring 72 does not rotate. When the linearly moving member 71 moves rearward from the front end of its range of movement, the convex portion 71d first moves within the groove 72b. At this time, the power conversion ring 72 does not rotate. When the convex portion 71d further retreats and moves rearward within the groove 72a, the convex portion 71d pushes against the wall of the groove 72a, causing the power conversion ring 72 to rotate clockwise when viewed from the front.

As shown in Figures 17 and 19, a cylindrical one-way clutch 73 and gear 74 are provided radially outward of shaft portion 72c. The inner peripheral surface of one-way clutch 73 is attached to the outer peripheral surface of shaft portion 72c. Gear 74 is attached to the outer peripheral surface of one-way clutch 73. One-way clutch 73 allows only counterclockwise rotational drive when viewed from the front, transmitting it from power conversion ring 72 to gear 74, but does not transmit clockwise rotational drive.

As shown in FIG. 15, the first rotation drive ring 75, the second rotation drive ring 76, and the third rotation drive ring 77 are arranged in this order from rear to front in front of the female screw member 27. The first rotation drive ring 75, the second rotation drive ring 76, and the third rotation drive ring 77 are substantially cylindrical with the screw shaft axis K as the center. The first rotation drive ring 75, the second rotation drive ring 76, and the third rotation drive ring 77 are provided at their centers with insertion holes 75c, 76e, and 77b that penetrate in the front-rear direction. The screw shaft 28 is inserted through the insertion holes 75c, 76e, and 77b so as to be movable in the front-rear direction. The first rotation drive ring 75 is provided on its outer circumferential surface with a gear 75a that meshes with the gear 74 (see FIG. 17). The first rotation drive ring 75 rotates around the screw shaft axis K by the rotation drive of the gear 74. The first rotation drive ring 75 meshes with the gear 74, which is restricted to one direction of rotation, and therefore rotates only in a clockwise direction as viewed from the front. The inner peripheral surface of the first rotation drive ring 75 is provided with a plurality of engagement protrusions 75b (see FIG. 16) that protrude radially inward. The engagement protrusions 75b are arranged at a predetermined interval, for example, at 90° intervals, in the circumferential direction.

As shown in FIG. 15, the outer peripheral surface of the second rotation drive ring 76 is provided with a plurality of grooves 76a extending in the front-rear direction. By inserting the second rotation drive ring 76 into the insertion hole 75c of the first rotation drive ring 75, the plurality of grooves 76a engage with the plurality of engagement protrusions 75b. Therefore, the second rotation drive ring 76 can rotate integrally with the first rotation drive ring 75 around the screw shaft axis K, and can slide in the front-rear direction relative to the first rotation drive ring 75. A spring receiving portion 76d that protrudes radially outward is provided at the front of the outer peripheral surface of the second rotation drive ring 76. A spring receiving portion 75d is provided at the front surface of the first rotation drive ring 75. A compression spring 76c is interposed between the spring receiving portion 76d and the spring receiving portion 75d. The second rotation drive ring 76 is biased forward by the compression spring 76c. The front end face of the second rotary drive ring 76 is provided with multiple meshing teeth 76b that have a shape in which protrusions and recesses in the front-rear direction are repeated in the circumferential direction.

As shown in FIG. 15, the rear end surface of the third rotation drive ring 77 is provided with multiple meshing teeth 77a, which have a shape in which protrusions and recesses in the front-rear direction are repeated in the circumferential direction. When the meshing teeth 76b and the meshing teeth 77a engage with each other, the second rotation drive ring 76 and the third rotation drive ring 77 can rotate together around the screw shaft axis K. The front end surface of the third rotation drive ring 77 is provided with an engaging protrusion that engages with the engaging recess 4b of the jaw 4 (see FIG. 13). The multiple jaws 4 can rotate together with the third rotation drive ring 77 around the screw shaft axis K.

The drive of the feed screw mechanism 60 and the power conversion mechanism 30 will be described with reference to Figures 15, 17, and 19. First, the rotational drive of the output shaft 21a of the electric motor 21 is decelerated by the planetary reduction mechanism 23 and transmitted to the upstream spindle 61. When the upstream spindle 61 rotates, the female screw member 27 rotates due to the meshing of gear 62 with gear 27a, and the spindle 64 rotates due to the meshing of gear 63 with gear 65. When the female screw member 27 rotates, the screw shaft 28 moves in the front-rear direction due to the screwing of the female screw 27b with the male screw 28a. The multiple jaws 4 open radially outward relative to each other as the screw shaft 28 advances, and close radially inward as the screw shaft 28 retreats.

When the spindle 64 rotates, the linear movement member 71 moves in the front-rear direction due to the engagement of the female screw 64a and the male screw 71a and the restriction of the rotation of the linear movement member 71 by the rotation restriction portion 54f. When the linear movement member 71 advances and the convex portion 71d advances in the groove 72a, the power conversion ring 72 rotates in the counterclockwise direction as viewed from the front side. The rotational drive of the power conversion ring 72 is transmitted to the gear 74 via the one-way clutch 73. The first rotation drive ring 75 rotates in the clockwise direction as viewed from the front side due to the meshing of the gear 74 and the gear 75a. The second rotation drive ring 76, the third rotation drive ring 77, and the multiple jaws 4 rotate integrally with the first rotation drive ring 75. When the convex portion 71d advances in the groove 72b, the power conversion ring 72 does not rotate. Therefore, the first rotational drive ring 75, the second rotational drive ring 76, the third rotational drive ring 77, and the multiple jaws 4 do not rotate.

When the linearly moving member 71 retreats and the convex portion 71d retreats within the groove 72b, the power conversion ring 72 does not rotate. Therefore, the first rotation drive ring 75, the second rotation drive ring 76, the third rotation drive ring 77, and the multiple jaws 4 do not rotate. When the convex portion 71d retreats within the groove 72a, the power conversion ring 72 rotates in a clockwise direction as viewed from the front. The one-way clutch 73 transmits only the rotation drive in the counterclockwise direction as viewed from the front to the gear 74. Therefore, the first rotation drive ring 75, the second rotation drive ring 76, the third rotation drive ring 77, and the multiple jaws 4 downstream of the power transmission path of the gear 74 do not rotate.

As described above, the pipe expansion tool 50 has an upstream spindle 61 that overlaps the spindle 64 in the front-rear direction and is axially rotated by the electric motor 21, as shown in FIG. 17. The axial rotation of the upstream spindle 61 causes the female thread member 27 and the spindle 64 to rotate. Therefore, by overlapping the upstream spindle 61 with the spindle 64 in the front-rear direction, the pipe expansion tool 50 can be made even shorter in the front-rear direction.

Various modifications can be made to the embodiment described above. A tube expansion tool 1, 50 having six jaws 4 has been shown as an example. Alternatively, the tool may have, for example, five or fewer jaws 4 or seven or more jaws 4.

The illustrated example shows a groove 32a that is inclined counterclockwise toward the front when viewed from the front, and a one-way clutch 33 that transmits only clockwise rotational drive when viewed from the front. The illustrated example also shows a groove 72a that is inclined clockwise toward the front when viewed from the front, and a one-way clutch 73 that transmits only counterclockwise rotational drive when viewed from the front. The inclination direction of the grooves 32a, 72a and the direction in which the one-way clutches 33, 73 transmit the rotational drive may be reversed from the example shown.

The configuration is exemplified in which the linear moving member 31 is provided with a radially protruding convex portion 31b, and the power conversion ring 32 is provided with grooves 32a, 32b on its outer peripheral surface. Alternatively, for example, a groove may be provided on the side surface of the linear moving member 31, and a convex portion protruding radially from the outer peripheral surface of the power conversion ring 32 may be provided. The linear moving members 31, 71 that move in the front-rear direction along the extension direction of the spindles 24, 64 are exemplified. Alternatively, for example, the linear moving members 31, 71 may move in the left-right direction or the up-down direction. The configuration is exemplified in which the front mechanism housing 12 is provided with a rotation restriction portion 12d that restricts the rotation of the linear moving member 31. Also, the configuration is exemplified in which the second central mechanism housing 54 is provided with a rotation restriction portion 54f that restricts the rotation of the linear moving member 71. The housing in which the rotation restriction portions 12d, 54f are provided is not limited to this.

The pipe expanding tool 1 is exemplified in which the motor axis J is located below the screw shaft axis K. Also, the pipe expanding tool 50 is exemplified in which the spindle axis P is located below the screw shaft axis K and above the motor axis J. The positional relationship of the motor axis J and spindle axis P with respect to the screw shaft axis K is not limited to this. Also, the motor axis J or spindle axis P may be inclined with respect to the screw shaft axis K.

The feed screw mechanisms 25 and 60 are exemplified in which balls 28b are interposed between the screw shaft 28 and the female screw member 27. Alternatively, for example, the feed screw mechanism may be one in which the screw shaft 28 and the female screw member 27 are directly screwed together and no balls are interposed.

1... Pipe enlargement tool 2... Cap, 2a... Jaw support groove, 2b... Female thread 3... Wedge 4... Jaw, 4a... Ring accommodating groove, 4b... Engagement recess, 4c... Ring 5... Grip 6... Switch lever, 6a... Switch body 7... Enlargement portion, 7a... Battery attachment portion 8... Battery 10... Tool body 11... Body housing, 11a... Slot 12... Front mechanism housing, 12a... Male thread, 12b... Engagement portion, 12c... Rectangular protrusion 12d... Rotation restriction portion, 12e... Through hole 13... First central mechanism housing, 13a, 13b... Engagement portion, 13c... Boss portion 13d... Recess, 13e... Inner circumferential surface, 13f... Through hole 14... Second central mechanism housing, 14a, 14b... Engagement portion, 14c... Boss portion 14d... Recess, 1 4e...inner circumferential surface, 14f...through hole 15...rear mechanism housing, 15a...front surface, 15b...engagement portion, 15c...boss portion 15d...threaded hole 16...bolt 20...motor housing 21...electric motor, 21a...output shaft, 21b...stator, 21c...rotor 21d...rotation 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 carrier, 23e...second sun gear 23f...second internal gear, 23g...second planetary gear, 23h...second carrier 24...spindle, 24a...male thread, 24b, 24c...spindle bearing 25...feed screw mechanism (ball screw mechanism)
26... gear 27... female screw member, 27a... gear, 27b... female screw, 27c, 27d... female screw member bearing 27e... thrust bearing, 27f... washer 28... screw shaft, 28a... male screw, 28b... ball 29... screw shaft guide, 29a... support member, 29b... roller, 29c... rail 30... power conversion mechanism 31... linear movement member (first member), 31a... female screw, 31b... convex portion, 31c... Roller 32...power conversion ring (second member), 32a...groove, 32b...groove, 32c...washer 32d...insertion hole 33...one-way clutch 34...first rotation drive ring, 34a...small diameter portion, 34b...large diameter portion, 34c...groove 34d...insertion hole 35...second rotation drive ring, 35a...engagement protrusion, 35b...engagement teeth, 35c...compression spring 35d...spring receiving portion, 35e...insertion hole 36...third Rotation drive ring, 36a...engagement teeth, 36b...engagement protrusion, 36c...insertion hole 41...initial position sensor 42...terminal position sensor 43...magnet 44...position adjustment mechanism, 44a...operation unit 45...controller 50...pipe enlargement tool 51...tool body 52...front mechanism housing, 52a...male thread, 52b...engagement portion, 52c...boss portion 53...first central mechanism housing, 53a, 53b...engagement portion, 53c...boss portion 53d...recess 54...second central mechanism housing, 54a, 54b...engagement portion, 54c...boss portion 54d...recess, 54e...inner circumferential surface, 54f...rotation restriction portion 55...third central mechanism housing, 55a...engagement portion, 55c...boss portion, 55d...inner circumferential surface 56...rear mechanism housing, 56c...boss portion, 56d, 56e...hole 57...bolt 60...feed screw mechanism (ball screw mechanism)
61...upstream spindle, 61a, 61b...spindle bearing 62...gear 63...gear 64...spindle, 64a...female thread, 64b...spindle bearing 65...gear 70...power conversion mechanism 71...linear moving member, 71a...male thread, 71b...sliding portion, 71c...mounting hole, 71d...projection 71e...roller 72...power conversion ring, 72a, 72b...groove, 72c...shaft portion, 72d...bearing 72e...ring portion 7 3...One-way clutch 74...Gear 75...First rotation drive ring, 75a...Gear, 75b...Engagement protrusion, 75c...Through hole 75d...Spring receiver 76...Second rotation drive ring, 76a...Groove, 76b...Engaging teeth, 76c...Compression spring 76d...Spring receiver, 76e...Through hole 77...Third rotation drive ring, 77a...Engaging teeth, 77b...Through hole J...Motor axis K...Screw shaft axis P...Spindle axis

Claims (11)

A pipe enlarging tool for enlarging an end of a synthetic resin fluid pipe,
An electric motor;
a female screw member rotated by the electric motor;
A screw shaft that is screwed into the female screw member and moves in the front-rear direction by rotation of the female screw member;
A wedge extending forward from the screw shaft;
a plurality of jaws that are pushed by the wedge and open radially outwardly relative to each other when the wedge advances together with the screw shaft;
a rotational drive ring coupled to the rear of the plurality of jaws;
a spindle axially rotated by the electric motor to rotate the rotary drive ring;
a linear motion member that is screwed to the spindle and moves linearly as the spindle rotates about its axis;
A tube expanding tool having a power conversion mechanism that is provided between the linear motion member and the rotary drive ring and converts the linear motion of the linear motion member into rotation of the rotary drive ring. 2. The tube expanding tool according to claim 1,
The spindle is a pipe expanding tool extending parallel to the screw axis. 3. The tube expanding tool according to claim 2,
The power conversion mechanism includes a power conversion ring that is rotatable coaxially with the rotary drive ring;
a protrusion protruding from a first member of the two members, the linearly moving member and the power conversion ring, toward a second member;
A pipe expanding tool having a groove in the second member extending in the direction of linear movement and in a circumferential direction, and through which the protrusion is inserted. 4. The tube expanding tool according to claim 3,
A tube expanding tool comprising a one-way clutch provided between the power conversion ring and the rotation drive ring for restricting the rotation direction of the rotation drive ring to one direction. 5. The tube expanding tool according to claim 4,
the rotational drive ring is provided radially inward of the power conversion ring,
A tube expanding tool, wherein the one-way clutch is provided radially between the power conversion ring and the rotation drive ring. A tube expanding tool according to any one of claims 3 to 5,
A pipe expanding tool, wherein the rotary drive ring and the power conversion ring have insertion holes through which the wedge or the screw shaft passes. A tube expanding tool according to any one of claims 3 to 6,
A tube expanding tool in which a roller is provided on the outer periphery of the convex portion, and the roller abuts against the wall surface of the groove. A tube expanding tool according to any one of claims 3 to 7,
A tube expanding tool provided with a rotation restricting portion extending in the front-rear direction along the linearly moving member to restrict axial rotation of the linearly moving member. A tube expanding tool according to any one of claims 3 to 8,
A pipe expanding tool, wherein the power conversion ring is provided in front of the female thread member. A tube expanding tool according to any one of claims 1 to 9,
A pipe expanding tool in which a ball is interposed between the screw shaft and the female threaded member. A tube expanding tool according to any one of claims 1 to 10,
a pipe expanding tool having an upstream spindle which overlaps with the spindle in the front-to-rear direction and is axially rotated by the electric motor, the female thread member and the spindle being axially rotated by the axial rotation of the upstream spindle;

Images