Pipe expansion tools

Abstract

To provide a tube diameter expansion tool capable of holding in a stable condition and favorable in operability.SOLUTION: A tube diameter expansion tool 1 for expanding the diameter of an end part of a fluid tube made by a synthetic resin has: an electric motor 21 housed in a main body housing 11; a screw shaft 28 provided to the main body housing 11 movably parallel to an output axis 21a of the electric motor 21 or in a longitudinal direction on an axis line; a female screw member 27 screwed on the screw shaft 28 to move the shaft 28 back and forth by rotating around the shaft 28; a gear 26 passing along the rotation of an output axis 21a of the electric motor 21 to the female screw member 27 by engaging mutually outside ; a chock 3 extending from the screw shaft 28 to forward; and a plurality of jaws 4 connected with the housing 11 to be openable and closable so that the jaws open mutually outside in a radial direction by being pushed by the chock 3 when the chock 3 advances together with the screw shaft 28.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a pipe diameter expanding tool for expanding the diameter of an end of a fluid pipe made of, for example, synthetic resin, in order to connect the end of the pipe to a connected body. [Background technology]

[0002] For example, a fluid pipe made of PEX (cross-linked polyethylene) may be connected to a connecting object such as a metal pipe. Pipe expansion tools have been available to expand the inner diameter of the end of the PEX pipe. The end of the PEX pipe is expanded using the pipe expansion tool and attached to the connecting object. The end of the PEX pipe is gradually reduced in diameter by elastic deformation, gradually returning to its original diameter. The PEX pipe with its reduced end is tightly connected to the connecting object. The connected PEX pipe is firmly held to the connecting object using its own elasticity.

[0003] Patent Document 1 describes a pipe expanding tool that uses an electric motor as a drive source to expand the diameter of a PEX pipe. The front of the pipe expanding tool is provided with a generally conical wedge that moves forward or backward relative to the end of the PEX pipe, and multiple jaws that are aligned circumferentially 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 pipe can be expanded by opening the multiple jaws radially outward while they are inserted into the end opening of the PEX pipe.

[0004] The tool body of the pipe expanding tool is provided with an electric motor and a planetary reduction mechanism that reduces the output of the electric motor. The pipe expanding tool is also provided with a generally columnar grip that extends downward from the tool body. A user holds the pipe expanding tool by grasping the grip. In Patent Document 1, the heavy electric motor is disposed in front of the grip. As a result, the center of gravity of the tool body is shifted forward, reducing the stability of the tool body when the grip is held. In addition, the planetary reduction mechanism, which has a relatively large diameter and a long axial length, is disposed between the grip and the electric motor in the vertical direction. As a result, the pipe expanding tool becomes longer in the vertical direction, further reducing the stability of the tool body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent No. 2020 / 0261959 Summary of the Invention [Problem to be solved by the invention]

[0006] There is room for improvement in pipe expansion tools to enable users to hold the tool in a stable state. Therefore, there is a need for a pipe expansion tool that can be held in a stable state and is easy to operate. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a pipe expanding tool for expanding the diameter of an end of a synthetic resin fluid pipe has an electric motor housed in a main housing. The pipe expanding tool has a threaded shaft mounted on the main housing so as to be movable back and forth parallel to or along the axis of the output shaft of the electric motor. The pipe expanding tool has a female threaded member that is threadedly engaged with the threaded shaft and rotates about the axis of the threaded shaft to move the threaded shaft back and forth. The pipe expanding tool has a gear that meshes with the female threaded member and transmits the rotation of the output shaft of the electric motor. The pipe expanding tool has a wedge extending forward from the threaded shaft. The pipe expanding tool has multiple jaws that are openably connected to the main housing so that the jaws are pushed by the wedge when the wedge advances together with the threaded shaft, opening radially outward relative to each other.

[0008] Therefore, the electric motor is positioned so that its output shaft extends parallel to the screw shaft. This positions the electric motor so that it extends in the front-to-rear direction along the screw shaft and is close to the screw shaft. Alternatively, the electric motor is positioned so that its output shaft extends coaxially with the screw shaft. This positions the electric motor close to the screw shaft. In this way, the heavy electric motor can be brought closer to the center of the main housing where the screw shaft is located. This improves weight balance and allows the pipe expansion tool to be held in a stable state. This improves the operability of the pipe expansion tool. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a tube expansion tool according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view of the tool body with the main body housing removed. [Figure 3] FIG. 2 is a right side view of the tool body with the main body housing removed. [Figure 4] FIG. [Figure 5] FIG. 10 is a longitudinal cross-sectional view of the tube expanding tool with the wedge positioned at the initial position. [Figure 6] FIG. 10 is a vertical cross-sectional view of the tool body when the rotation of the jaws is completed. [Figure 7] FIG. 10 is a longitudinal sectional view of the tool body with the wedge positioned at the end position. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5. [Figure 9] FIG. [Figure 10] 10 is a view of the jaw rotation mechanism when viewed from below on the left side with the wedge in the initial position. FIG. [Figure 11] 10 is a view of the jaw rotation mechanism when the jaw rotation is completed, viewed from the bottom left side. FIG. [Figure 12] FIG. 10 is a view of the jaw rotation mechanism from below on the left side with the wedge in the terminal position. [Figure 13] FIG. 10 is a rear perspective view of the jaw. DETAILED DESCRIPTION OF THE INVENTION

[0010] According to another feature of the present disclosure, the tube expansion tool has a grip extending downward from the main housing. The grip is provided between the electric motor and the multiple jaws in the front-rear direction. The electric motor is disposed below the screw shaft. Therefore, the electric motor and the multiple jaws are disposed so that their weights are well balanced relative to the grip. This improves the operability of the tube expansion tool when a user holds the grip.

[0011] According to another feature of the present disclosure, at least a portion of the screw shaft and the grip overlap in the front-to-rear direction, which allows the tube expansion tool to be shortened in the front-to-rear direction, thereby reducing the moment around the center of gravity of the tube expansion tool and further improving operability.

[0012] According to another feature of the present disclosure, a planetary reduction mechanism that reduces the output of the output shaft is provided between the output shaft of the electric motor and the screw shaft. Therefore, the planetary reduction mechanism can be compactly arranged on the power transmission path from the electric motor to the screw shaft. Furthermore, by minimizing the power transmission path from the electric motor to the screw shaft, power transmission loss can be suppressed.

[0013] According to another feature of the present disclosure, the pipe expansion tool has a rotary drive ring connected to the rear portions of the multiple jaws. The pipe expansion tool has a jaw rotation mechanism that rotates the rotary drive ring using the output of an electric motor to rotate the multiple jaws in the circumferential direction. The rotary drive ring is provided in front of the female threaded member. Therefore, the female threaded member, the rotary drive ring, and the multiple jaws are arranged side by side in the front-to-rear direction in which the screw shaft extends. This allows the center of gravity of the pipe expansion tool to be closer to the screw shaft. This increases stability when holding the pipe expansion tool.

[0014] According to another feature of the present disclosure, a pipe expanding tool has a cap that supports multiple jaws so that they can be opened and closed and that restricts the forward and backward movement of the multiple jaws. The pipe expanding tool has a front mechanism housing, a central mechanism housing, and a rear mechanism housing arranged in this order from front to rear within a main body housing. The pipe expanding tool has a bolt that connects the front mechanism housing and the rear mechanism housing. The front mechanism housing is made of iron and supports the cap. The rear mechanism housing is made of iron and supports the rear end of the female thread member. The central mechanism housing is formed of a material lighter than iron.

[0015] Therefore, the structure is divided in the front and rear directions into a front mechanism housing, a central mechanism housing, and a rear mechanism housing. The cap and the front mechanism housing supporting the cap are pushed forward with a strong force by the jaws when they open. The female threaded member is pushed backward with a strong force as a reaction to the forward movement of the screw shaft. For example, if the front mechanism housing, the central mechanism housing, and the rear mechanism housing are formed as a single, integrated mechanism housing, strong tensile forces in the front and rear directions are generated at the front and rear ends when the jaws are expanded. Therefore, the entire mechanism housing must be made with high strength. The front mechanism housing, the central mechanism housing, and the rear mechanism housing are divided in the front and rear directions, and the front mechanism housing and the rear mechanism housing are made of steel. This allows the tensile forces in the front and rear directions to be distributed between the front and rear mechanism housings, which have high strength. Furthermore, by making the central mechanism housing out of a lightweight material, the weight of the pipe expanding tool can be reduced.

[0016] According to another feature of the present disclosure, the tube expanding tool has a second central mechanism housing between a central mechanism housing and a 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 where adjacent ends overlap each other in the front-to-rear direction. Therefore, by overlapping each engaging portion in the front-to-rear direction, the front mechanism housing and the central mechanism housing can be accurately positioned relative to each other. Furthermore, the engaging portion between the central mechanism housing and the second central mechanism housing and the engaging portion between the second central mechanism housing and the rear mechanism housing can also be accurately positioned. This improves the assembly of each mechanism housing and suppresses rattle of the internally threaded members and the like housed therein.

[0017] According to another feature of the present disclosure, a spindle 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 a spindle bearing that rotatably supports the spindle and an internal thread member bearing that rotatably supports the internal thread member. Therefore, the spindle bearing and the internal thread member bearing are hardly subjected to forces in the front-to-rear direction. Therefore, the central mechanism housing and the second central mechanism housing, which have lower strength than the front mechanism housing and the rear mechanism housing, can adequately support the spindle and the internal thread member. This reduces the number of parts that need to be made of iron, thereby reducing the weight of the pipe expansion tool.

[0018] According to another feature of the present disclosure, the rear mechanism housing supports a thrust bearing that abuts against the rear end of the female threaded member. Therefore, the female threaded member is pushed rearward with a strong force when the screw shaft moves forward. The rear mechanism housing can receive the force pushing the female threaded member rearward via the thrust bearing. Therefore, the female threaded member can rotate precisely around the axis of the screw shaft. This allows the screw shaft to move precisely in the forward and backward directions.

[0019] According to another feature of the present disclosure, balls are interposed in the threaded engagement portion between the screw shaft and the female screw member. Therefore, the balls interposed in the threaded engagement portion improve the transmission efficiency of the driving force. As a result, 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.

[0020] Next, one embodiment of the present disclosure will be described with reference to Figures 1 to 13. As shown in Figure 1, the pipe expanding tool 1 of this embodiment has a tool body 10 housed in a substantially cylindrical main body housing 11, and a grip 5 extending downward from the center of the tool body 10 in the front-to-rear direction. A user holds the grip 5 while positioned approximately at the rear of the pipe expanding tool 1 (the far left side in Figure 1). 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 up, down, left, and right directions are based on the user.

[0021] As shown in FIGS. 1 and 4 , a ring-shaped cap 2 is attached to the front of the main housing 11, forward of the grip 5. A substantially conical wedge 3 extending in the front-rear direction is provided inside the inner circumferential 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 allows the wedge 3 to move in the front-rear direction together with the screw shaft 28. 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 around the circumferential direction of the wedge 3. For example, six jaws 4 are provided, and the jaws 4 are arranged at 60° intervals around the circumferential direction of the wedge 3. The plurality of jaws 4 are radially openable and closable between a closed position in which they are closely spaced around the circumferential direction to cover the wedge 3, and an open position in which they are spaced apart radially outward to expose the tips of the wedge 3.

[0022] 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. A switch main body 6a is provided inside the grip 5 and is switched on and off in conjunction with the operation of the switch lever 6. The switch main body 6a is in the off state when the switch lever 6 is not pulled, and is switched on when the switch lever 6 is pulled. An expanded diameter portion 7 having a substantially rectangular box shape and expanding in the front-to-back and left-to-right directions relative to the grip 5 is provided at the bottom end of the grip 5. The expanded diameter portion 7 houses a controller 45. The controller 45 has a shallow rectangular box-shaped case and a resin-molded control board housed in the case. The controller 45 is housed in the expanded diameter portion 7 with its thickness (the direction in which the shortest side of the case extends) aligned vertically. The controller 45 mainly controls the driving of the electric motor 21, which will be described later.

[0023] As shown in FIG. 1, a battery mounting portion 7a is provided on the underside of the enlarged diameter portion 7, to which a rectangular box-shaped battery 8 can be removably attached. The battery 8 can be removed from the battery mounting portion 7a by sliding it forward relative to the battery mounting portion 7a. The battery 8 can be attached to the battery mounting portion 7a by sliding it from the front to the rear of the battery mounting portion 7a. The battery 8 can be removed from the battery mounting portion 7a and repeatedly charged and used using a separately provided charger. The battery 8 can also be used as a power source for other power tools. The battery 8 operates as a power source that supplies power to the electric motor 21.

[0024] As shown in FIG. 4, the main body housing 11 accommodates a front mechanism housing 12, a first central mechanism housing 13, a second central mechanism housing 14, and a rear mechanism housing 15, in this order from front to rear. The front mechanism housing 12, the first central mechanism housing 13, and the second central mechanism housing 14 are each substantially cylindrical with a central through-hole that penetrates in the front-to-rear direction. The rear mechanism housing 15 is plate-shaped with its thickness in the front-to-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 a spindle 24 and an internally threaded member 27, which will be 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.

[0025] 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 substantially 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-to-rear direction are formed at the four corners of the rectangular protrusion 12c.

[0026] 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 of the bosses 13c, 14c, and 15c is formed in a generally cylindrical shape extending 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 of the bosses 13c, 14c. A screw hole 15d that extends in the front-to-rear direction is provided in the center of each of the bosses 15c.

[0027] 2 and 4, by aligning 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 hole 15d are communicated in the front-to-rear direction. Four bolts 16 are inserted from front to rear through the communicated through holes 12e, 13f, and 14f and fastened to the screw hole 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.

[0028] 3 to 5, a substantially cylindrical engaging portion 12b and an engaging portion 13a are provided at the rear end of the front mechanism housing 12 and the front end of the first central mechanism housing 13, respectively. The inner circumferential surface of engaging portion 12b and the outer circumferential surface of engaging portion 13a have substantially the same diameter. Engaging portions 12b and 13a overlap in the front-to-rear direction and engage in a so-called spigot-joint 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.

[0029] 3 to 5, a substantially cylindrical engaging portion 13b and an engaging portion 14a are provided at the rear end of the first central mechanism housing 13 and the front end of the second central mechanism housing 14, respectively. The inner circumferential surface of engaging portion 13b and the outer circumferential surface of engaging portion 14a have substantially the same diameter. Engaging portions 13b and 14a overlap in the front-to-rear direction and engage with each other in a spigot-joint 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.

[0030] As shown in Figures 3 to 5, a generally cylindrical engaging portion 14b is provided at the rear end of the second central mechanism housing 14. A generally cylindrical engaging portion 15b that protrudes forward is provided at the front surface of the rear mechanism housing 15. The inner circumferential surface of engaging portion 14b and the outer circumferential surface of engaging portion 15b have generally the same diameter. Engaging portions 14b and 15b overlap in the front-to-rear direction and engage in a spigot-joint structure in which the inner circumferential surface of engaging portion 14b and the outer circumferential surface of engaging portion 15b are in close contact with each other.

[0031] 1 and 5, a substantially cylindrical motor housing 20 that houses an electric motor 21 is provided at the rear of the main body housing 11. The motor housing 20 is located below the screw shaft 28 and above the rear of the grip 5. For example, a motor called a DC brushless motor is used as the electric motor 21. An 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 by bearings 21e and 21f attached to the motor housing 20 so as to be rotatable about the motor axis J.

[0032] As shown in FIG. 5, a stator 21b of the electric motor 21 is non-rotatably supported on the inner circumferential surface of the motor housing 20. A rotor 21c of the electric motor 21 is attached to the output shaft 21a on the inner circumferential 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 speed of the output shaft 21a by detecting the rotation angle of the rotor 21c. 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-to-rear direction. When the fan 22 rotates together with the output shaft 21a, cooling air flows from the front to the rear of the motor housing 20.

[0033] 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, centered on the motor axis J and having substantially the same diameter as the electric motor 21. A first sun gear 23a is provided integrally with the front end of the output shaft 21a at the rear end of the planetary reduction mechanism 23. A ring-shaped first internal gear 23b is provided radially outward from the first sun gear 23a and is 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 gears 23c.

[0034] As shown in FIG. 5 , first carrier 23d is provided integrally with second sun gear 23e in front thereof and is rotatable together with second sun gear 23e about motor axis line J. A ring-shaped second internal gear 23f is provided radially outward of second sun gear 23e and is centered on motor axis line J. A plurality of second planetary gears 23g mesh between second sun gear 23e and second internal gear 23f. Second planetary gears 23g are connected to second carrier 23h disposed in front of second sun gear 23e. Second carrier 23h is provided integrally with spindle 24 in front thereof and is rotatable about motor axis line J. Therefore, the rotational drive of first carrier 23d is transmitted to spindle 24 at a reduced speed via second sun gear 23e, second planetary gears 23g, and second carrier 23h. Thus, the rotational drive of the output shaft 21 a is transmitted to the spindle 24 via the planetary reduction mechanism 23 at a reduced speed.

[0035] As shown in FIG. 5, the spindle 24 is supported by spindle bearings 24b and 24c 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 housed in a space formed by the first central mechanism housing 13 and the second central mechanism housing 14 working together. A gear 26 for transmitting power to the screw shaft 28 is provided on the spindle 24 so as to be rotatable integrally with the spindle 24. 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.

[0036] As shown in FIGS. 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, an internally threaded member 27, and a gear 26. The screw shaft 28 is disposed on a screw shaft axis K extending in the front-rear direction at the center of the main body housing 11. The screw shaft 28 is movable in the front-rear direction along the screw shaft axis K. At least a portion of the screw shaft 28 overlaps with the grip 5 in the front-rear direction at any position from the rear end to the front end of its movement range. When the screw shaft 28 is located at the rear end of its movement range, the screw shaft 28 overlaps with the output shaft 21a in the front-rear direction. The internally threaded member 27 is formed in a substantially cylindrical shape that threadably engages with the screw shaft 28 and the gear 26. An internal thread 27b is provided on the inner peripheral surface of the internally threaded member 27. The internal thread 27b is threadably engaged with the external thread 28a of the screw shaft 28 via a plurality of balls 28b. A gear 27a that protrudes radially outward and meshes with the gear 26 is provided at the center of the female screw member 27 in the front-to-rear direction. The meshing of the gear 27a with the gear 26 transmits the rotational drive of the spindle 24 to the female screw member 27 at a reduced speed.

[0037] As shown in Figures 4 and 5, the female thread member 27 is supported rotatably about the screw shaft axis K by front and rear female thread member bearings 27c, 27d. The female thread member bearing 27c at the front of the gear 27a is press-fitted into the inner circumferential surface 13e of the first central mechanism housing 13. The female thread member bearing 27d at the rear of the gear 27a is press-fitted into the inner circumferential surface 14e of the second central mechanism housing 14. The female thread member bearings 27c, 27d are housed in a space formed by the first central mechanism housing 13 and the second central mechanism housing 14 working together. A thrust bearing 27e is provided between the rear surface of the female thread member 27 and the front surface 15a of the rear mechanism housing 15 to bear a thrust load that pushes the female thread member 27 rearward. A washer 27f is provided between the front surface of the female thread member 27 and the rear surface of a power conversion ring 32, which will be described later.

[0038] 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 body housing 11. The screw shaft guide 29 has a support member 29a connected to the screw shaft 28 and extending in the left-right direction, and rollers 29b provided on both left and right ends of the support member 29a. A pair of loop-shaped rails 29c extending in the front-back direction are provided on the left and right inner peripheral surfaces of the main body 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.

[0039] As shown in FIGS. 4 and 5 , the tool body 10 is provided with a jaw rotation mechanism 30 that rotates the multiple jaws 4. The jaw rotation mechanism 30 includes a linear motion member 31 and a power conversion ring 32. The linear motion member 31 is formed in a substantially cylindrical shape with its axial direction aligned in the front-to-rear direction. The linear motion member 31 has a female thread 31a formed on its inner circumferential surface and a cylindrical protrusion 31b extending perpendicular to the axial direction of the substantially cylindrical shape. A roller 31c is provided at the upper end of the protrusion 31b, covering the protrusion 31b in the circumferential direction and rotatable around the axis of the protrusion 31b. The female thread 31a of the linear motion member 31 is threadedly engaged with the male thread 24a of the spindle 24. A rotation restricting portion 12d that restricts rotation of the linear motion member 31 is provided at the bottom of the front mechanism housing 12. The rotation restricting portion 12d is formed in a groove shape that radially penetrates the front mechanism housing 12 and linearly extends in the front-to-rear direction.

[0040] As shown in Figures 4 and 9, the power conversion ring 32 has a generally cylindrical shape with a central insertion hole 32d that penetrates in the front-to-rear direction. Grooves 32a and 32b are recessed into the outer peripheral surface of the lower part of the power conversion ring 32. Groove 32a extends in the circumferential direction of the power conversion ring 32, extending in a direction that intersects with the axial direction (front-to-rear direction) of the power conversion ring 32 at an inclination angle of 45°, for example. The inclination direction of groove 32a is counterclockwise toward the front when viewed from the front. Groove 32b extends parallel to the axial direction of the power conversion ring 32. A protrusion 31b equipped with a roller 31c is inserted into grooves 32a and 32b. The front end of groove 32a and the rear end of groove 32b are connected to allow smooth movement of protrusion 31b.

[0041] 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 threaded onto the male thread 24a of the spindle 24 at the bottom of the front mechanism housing 12. The convex portion 31b extends upward through the rotation restricting portion 12d and is inserted into the groove 32a or 32b. The roller 31c abuts against both the wall surfaces of the grooves 32a and 32b and the wall surface of the rotation restricting 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 restricting portion 12d.

[0042] As shown in Figures 10 to 12, when the spindle 24 rotates around its axis, the linear motion member 31 moves in the front-to-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 motion member 31 around its axis. When the linear motion 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 motion member 31 moves forward from the rear end, the convex portion 31b moves forward within the groove 32a. Because the rotation of the linear motion member 31 is restricted, the convex portion 31b does not move in the left-to-right direction. Therefore, the advancing convex portion 31b presses against the wall surface of the groove 32a. As a result, the power conversion ring 32 rotates clockwise around the screw shaft axis K as viewed from the front. When the linear motion 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-to-rear direction, no force is generated that causes the convex portion 31b to press against the wall surface of the groove 32b. Therefore, the power conversion ring 32 does not rotate.

[0043] 10 to 12, when the linearly 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, and 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.

[0044] 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 circumferential 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 rotational drive as viewed from the front, and transmits it from the power conversion ring 32 to the first rotation drive ring 34. On the other hand, counterclockwise rotational drive as viewed from the front is not transmitted from the power conversion ring 32 to the first rotation drive ring 34 via the one-way clutch 33.

[0045] As shown in Figures 4 and 5, the first rotation drive ring 34 has a generally cylindrical shape with a central through-hole 34d 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 cylindrical small-diameter portion 34a and a large-diameter portion 34b that are centered on the screw shaft axis K. The small-diameter portion 34a is disposed rearward of the large-diameter portion 34b. The small-diameter portion 34a is press-fitted into the inner circumferential surface of the one-way clutch 33. A plurality of grooves 34c extending in the front-rear direction are recessed in the outer circumferential surface of the large-diameter portion 34b. The 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.

[0046] As shown in Figures 4 and 5, a 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 has a generally cylindrical shape with a central insertion hole 35e that penetrates in the front-rear direction. The screw shaft 28 and the first rotation drive ring 34 are inserted into the insertion hole 35e. The inner circumferential surface of the second rotation drive ring 35 is provided with multiple engaging protrusions 35a that protrude radially inward. When the first rotation drive ring 34 is inserted into the insertion hole 35e, the multiple engaging protrusions 35a engage with the multiple recessed grooves 34c. Therefore, the second rotation drive ring 35 can rotate integrally with the first rotation drive ring 34 about the screw shaft axis K and can slide in the front-rear direction relative to the first rotation drive ring 34.

[0047] 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, each with a shape in which protrusions and recesses in the front-rear direction are repeated circumferentially, are provided at the front surface of the second rotation drive ring 35.

[0048] As shown in Figures 4 and 5, a third rotation drive ring 36 is provided in front of the second rotation drive ring 35 and engages with the second rotation drive ring 35 and the multiple jaws 4. The third rotation drive ring 36 is generally cylindrical and has a central insertion hole 36c that penetrates in the front-rear direction. The screw shaft 28 is inserted through the insertion hole 36c. The rear surface of the third rotation drive ring 36 is provided with multiple meshing teeth 36a, each of which has a circumferentially repeated pattern of concave and convex portions extending in the front-rear direction. The meshing teeth 36a engage with meshing teeth 35b of the second rotation drive ring 35. The third rotation drive ring 36 is rotatable integrally with the second rotation drive ring 35 around the screw shaft axis K through the meshing of the meshing teeth 35b and the meshing teeth 36a. The front end surface of the third rotation drive ring 36 is provided with multiple engagement protrusions 36b that protrude forward. Each of the engaging protrusions 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.

[0049] 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 backward against the biasing force of the compression spring 35c and moves away from the third rotation drive ring 36. This causes the meshing teeth 35b and 36a to disengage from each other. Therefore, the power transmission path for rotating the multiple jaws 4 about the screw shaft axis K is blocked between the second rotation drive ring 35 and the third rotation drive ring 36. This prevents an excessive rotational drive load from being applied to the jaws 4 that have bitten into the fluid pipe, and prevents damage to each component (e.g., the linearly moving member 31 that transmits power, the power conversion ring 32, and the rotation drive rings 34, 35, and 36).

[0050] As shown in Figures 5 to 7, a ring receiving groove 4a having an arc-shaped cross section is provided on the radial outer periphery of the rear portion of the jaw 4. The ring receiving 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 receiving groove 4a and is elastically expandable and contractible. A jaw support groove 2a that can receive the ring 4c is provided on the inner circumferential surface of the cap 2, extending radially outward and circumferentially. The jaw support groove 2a allows the ring 4c to move in the radial direction but restricts movement of the ring 4c in the front-to-rear direction. The multiple jaws 4 open and close radially around the ring 4c supported in the jaw support groove 2a.

[0051] As shown in Figures 5 to 7, the multiple jaws 4 open radially outward relative to one another as the wedge 3 advances, pressing the cap 2 forward and radially outward. The front mechanism housing 12, which is integral with the cap 2, is subjected to a strong tensile force directed forward as the wedge 3 advances. The female screw member 27 is pushed rearward as a reaction when the screw shaft 28, which is integral with the wedge 3, advances. The rear mechanism housing 15 is subjected to a force pushing the female screw member 27 rearward via the thrust bearing 27e. Therefore, a strong tensile force is generated between the front mechanism housing 12 and the rear mechanism housing 15, separating them from each other in the front-to-rear direction as the wedge 3 and the screw shaft 28 advance.

[0052] As shown in Figures 5 to 7, a first central mechanism housing 13 and a second central mechanism housing 14, which are separable in the front-to-rear direction, are interposed between the front mechanism housing 12 and the rear mechanism housing 15. Therefore, a forward force applied to the front mechanism housing 12 is not transmitted to the rear mechanism housing 15. Also, a rearward force applied to the rear mechanism housing 15 is not transmitted to the front mechanism housing 12. Furthermore, 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 enough rigidity to withstand a tensile force that moves them apart in the front-to-rear direction.

[0053] As shown in Figures 5 to 7, the first central mechanism housing 13 accommodates and supports the spindle bearing 24b and the female screw member bearing 27c. The second central mechanism housing 14 accommodates and supports the spindle bearing 24c and the female screw member bearing 27d. The spindle 24, which is rotatably supported by the spindle bearings 24b and 24c, is subjected to a reaction force from the forward and backward movement of the linearly moving member 31. However, this reaction force is significantly smaller than the reaction force the female screw member 27 receives. Therefore, the spindle bearings 24b and 24c receive almost no force in the forward and backward directions. The female screw member 27, which is rotatably supported by the female screw member bearings 27c and 27d, receives a force pushing it backward via the thrust bearing 27e. Therefore, the female screw member bearings 27c and 27d receive almost no force in the forward and backward directions. Furthermore, the first central mechanism housing 13 and the second central mechanism housing 14 can be separated in the forward and backward directions from the front mechanism housing 12 and the rear mechanism housing 15. Thus, the first central mechanism housing 13 and the second central mechanism housing 14 are hardly subjected to any force in the forward and backward directions during operation of the tube expanding tool 1. Therefore, the first central mechanism housing 13 and the second central mechanism housing 14 can be made of lightweight aluminum die-cast.

[0054] The drive of the feed screw mechanism 25 and the jaw rotation 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 reduced by the planetary reduction mechanism 23 and transmitted to the spindle 24. When the spindle 24 rotates, the gear 26 meshes with the gear 27a, causing the female thread member 27 to rotate. Furthermore, the linear movement member 31 moves in the front-rear direction due to the engagement of the male thread 24a with the female thread 31a and the restriction of the rotation of the linear movement member 31 by the rotation restriction portion 12d. When the female thread member 27 rotates, the screw shaft 28 moves in the front-rear direction due to the engagement of the female thread 27b with the male thread 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 radially outward to the open position. When the screw shaft 28 moves backward, the pressing force of the wedge 3 is released, so that the ring 4c contracts and the jaws 4 return to the closed position inward in the radial direction.

[0055] When the linearly moving member 31 advances and the convex portion 31b advances within the groove 32a, the power conversion ring 32 rotates clockwise as viewed from the front. 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 clockwise as viewed from the front. Therefore, the multiple jaws 4 supported by the third rotation drive ring 36 also rotate clockwise as viewed from the front. When the convex portion 31b advances 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.

[0056] When the linearly moving member 31 retracts and the convex portion 31b retracts 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 retracts within the groove 32a, the power conversion ring 32 rotates counterclockwise as viewed from the front. The one-way clutch 33 transmits only clockwise rotational drive to the first rotation drive ring 34 as viewed from the front. 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.

[0057] The electric motor 21 is switched between forward and reverse rotation by a controller 45 (see FIG. 1). When the electric motor 21 rotates forward, the multiple jaws 4 are pushed by the advancing wedges 3 and open radially outward relative to one another. When the electric motor 21 rotates forward, the multiple jaws 4 are rotated clockwise as viewed from the front by the jaw rotation mechanism 30. When the electric motor 21 rotates reversely, the multiple jaws 4 close radially inward relative to one another as the wedges 3 retract. 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.

[0058] The timing of the rotation of the multiple jaws 4 by the jaw rotation 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 changing 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 has finished.

[0059] 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 an 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 an initial position at the rear end of its range of movement. The initial position sensor 41 and the end position sensor 42 are sensors known as Hall ICs that detect magnetic fields. The initial position sensor 41 is fixed to the main body housing 11 above the screw shaft 28. The end position sensor 42 is supported by the main body housing 11 above the screw shaft 28 so as to be movable in the front-to-rear direction.

[0060] 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 top of the main body housing 11. A slot 11a is provided on the top surface of the main body housing 11, penetrating the main body housing 11 in the vertical direction and extending 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 top surface of the main body housing 11. The terminal position sensor 42 is supported on the inside of the main body housing 11 at the lower end of the operating part 44a. 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.

[0061] 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.

[0062] As described above, the pipe expanding tool 1 for expanding the end of a synthetic resin fluid pipe has an electric motor 21 housed in the main housing 11 as shown in FIGS. 5 to 7. The pipe expanding tool 1 has a threaded shaft 28 mounted in the main housing 11 so as to be movable in the forward and backward directions parallel to or along the axis of the output shaft 21a of the electric motor 21. The pipe expanding tool 1 has a female threaded member 27 that is threadedly engaged with the threaded shaft 28 and rotates about the axis of the threaded shaft 28, thereby moving the threaded shaft 28 forward and backward. The pipe expanding tool 1 has a gear 26 that meshes with the female threaded member 27 and transmits the rotation of the output shaft 21a of the electric motor 21. The pipe expanding tool 1 has a wedge 3 extending forward from the threaded shaft 28. The pipe expanding tool 1 has multiple jaws 4 that are openably connected to the main housing 11 so as to be pushed by the wedge 3 when the wedge 3 advances together with the threaded shaft 28 and open radially outward relative to each other.

[0063] Therefore, the electric motor 21 is disposed so that the output shaft 21a extends parallel to the screw shaft 28. As a result, the electric motor 21 is disposed so that it extends in the front-to-rear direction along the screw shaft 28 and is located close to the screw shaft 28. Alternatively, the electric motor 21 is disposed so that the output shaft 21a extends coaxially with the screw shaft 28. As a result, the electric motor 21 is disposed close to the screw shaft 28. In this way, the heavy electric motor 21 can be brought closer to the center of the main housing 11 where the screw shaft 28 is located. This improves the weight balance and allows the pipe expansion tool 1 to be held in a stable state. This improves the operability of the pipe expansion tool 1.

[0064] As shown in Figure 5, the pipe expanding tool 1 has a grip 5 that extends downward from the main body housing 11. The grip 5 is provided between the electric motor 21 and the multiple jaws 4 in the front-to-rear direction. The electric motor 21 is disposed below the screw shaft 28. Therefore, the electric motor 21 and the multiple jaws 4 are disposed so that they have a good weight balance relative to the grip 5. This improves the operability of the pipe expanding tool 1 when the user holds the grip 5.

[0065] As shown in Figure 5, at least a portion of the screw shaft 28 and the grip 5 overlap in the front-to-rear direction. This allows the pipe expanding tool 1 to be shortened in the front-to-rear direction. This reduces the moment around the center of gravity of the pipe expanding tool 1, further improving operability.

[0066] 5, a planetary reduction mechanism 23 that reduces the output of the output shaft 21a is provided between the output shaft 21a of the electric motor 21 and the screw shaft 28. Therefore, the planetary reduction mechanism 23 can be compactly arranged on the power transmission path from the electric motor 21 to the screw shaft 28. Furthermore, by minimizing the power transmission path from the electric motor 21 to the screw shaft 28, power transmission loss can be suppressed.

[0067] As shown in Figures 4 and 5, the pipe expansion tool 1 has rotation drive rings 34, 35, and 36 connected to the rear of the multiple jaws 4. The pipe expansion tool 1 has a jaw rotation mechanism 30 that rotates the rotation drive rings 34, 35, and 36 using the output of the electric motor 21 to rotate the multiple jaws 4 in the circumferential direction. The rotation drive rings 34, 35, and 36 are provided in front of the female thread member 27. Therefore, the female thread member 27, the rotation drive rings 34, 35, and 36, and the multiple jaws 4 are arranged side by side in the front-to-rear direction in which the screw shaft 28 extends. This allows the center of gravity of the pipe expansion tool 1 to be closer to the screw shaft 28. This increases stability when holding the pipe expansion tool 1.

[0068] As shown in Figures 4 and 5, the pipe expanding tool 1 has a cap 2 that supports multiple jaws 4 so that they can be opened and closed, and that restricts the forward and backward movement of the multiple jaws 4. The pipe expanding tool 1 has a front mechanism housing 12, a first central mechanism housing 13, and a rear mechanism housing 15, which are arranged in this order from front to rear within a main body housing 11. The pipe expanding tool 1 has a bolt 16 that connects the front mechanism housing 12 and the rear mechanism housing 15. The front mechanism housing 12 is made of iron and supports the cap 2. The rear mechanism housing 15 is made of iron and supports the rear end of the female thread member 27. The first central mechanism housing 13 is made of a material lighter than iron.

[0069] Therefore, the mechanism housing 12 is divided into the front and rear mechanism housings 12, 13, and 15 in the front-to-rear direction. The cap 2 and the front mechanism housing 12 supporting the cap 2 are pushed forward with a strong force by the jaws 4 when the jaws 4 are opened. The female screw member 27 is pushed backward with a strong force as a reaction to the forward movement of the screw shaft 28. For example, if the front mechanism housing 12, the first central mechanism housing 13, and the rear mechanism housing 15 are formed as a single, integrated mechanism housing, a strong tensile force in the front and rear directions occurs at the front and rear ends when the jaws 4 are expanded. Therefore, the entire mechanism housing must be made with high strength. The front mechanism housing 12, the first central mechanism housing 13, and the rear mechanism housing 15 are divided into the front and rear directions, and the front mechanism housing 12 and the rear mechanism housing 15 are made of steel. This allows the tensile force in the front and rear directions to be distributed among the front mechanism housing 12 and the rear mechanism housing 15, which have high strength. Furthermore, by providing the first central mechanism housing 13 from a lightweight material, the weight of the pipe expanding tool 1 can be reduced.

[0070] As shown in Figures 2 and 5, the pipe expanding tool 1 has a second central mechanism housing 14 between a first central mechanism housing 13 and a 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 have engaging portions 12b, 13a, 13b, 14a, 14b, and 15b at their respective ends, where adjacent ends overlap each other in the front-to-rear direction. Therefore, by overlapping the engaging portion 12b and the engaging portion 13a in the front-to-rear direction, the front mechanism housing 12 and the first central mechanism housing 13 can be accurately positioned relative to each other. In addition, the engaging portions 13b and 14a between the first central mechanism housing 13 and the second central mechanism housing 14 and the engaging portions 14b and 15b between the second central mechanism housing 14 and the rear mechanism housing 15 can also be accurately positioned. This improves the assembly of each mechanism housing and suppresses rattle of the internally threaded member 27 and other components housed therein.

[0071] As shown in FIG. 5, a spindle 24 that rotates integrally with a gear 26 is provided in front of the output shaft 21a. The first central mechanism housing 13 and the second central mechanism housing 14 support spindle bearings 24b and 24c that rotatably support the spindle 24 and female screw member bearings 27c and 27d that rotatably support the female screw member 27. Therefore, the spindle bearings 24b and 24c and the female screw member bearings 27c and 27d are hardly subjected to force in the front-to-rear direction. Therefore, the first central mechanism housing 13 and the second central mechanism housing 14, which have lower strength than the front mechanism housing 12 and the rear mechanism housing 15, can adequately support the spindle 24 and the female screw member 27. This reduces the number of parts that need to be made of iron, thereby reducing the weight of the pipe expanding tool 1.

[0072] As shown in Figure 5, the rear mechanism housing 15 supports a thrust bearing 27e that abuts against the rear end of the female screw member 27. Therefore, the female screw member 27 is pushed rearward with a strong force when the screw shaft 28 moves forward. The rear mechanism housing 15 can receive the force pushing the female screw member 27 rearward via the thrust bearing 27e. Therefore, the female screw member 27 can rotate precisely around the axis of the screw shaft 28. This allows the screw shaft 28 to move precisely in the front-to-rear direction.

[0073] As shown in Figure 5, balls 28b are interposed in the threaded portion between the screw shaft 28 and the female screw member 27. Therefore, the balls 28b interposed in the threaded portion improve the transmission efficiency of the driving force. As a result, 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.

[0074] Various modifications can be made to the present embodiment described above. The pipe expanding tool 1 has been exemplified as having six jaws 4. Alternatively, for example, the tool may have five or fewer jaws 4, or seven or more jaws 4. The electric motor 21 is provided below the screw shaft 28 and above the rear of the grip 5. Alternatively, for example, the electric motor 21 may be provided above the screw shaft 28 and above the rear of the grip 5.

[0075] In the illustrated example, the first central mechanism housing 13 and the second central mechanism housing 14 are interposed between the front and rear mechanism housings 12 and 15. Alternatively, a central mechanism housing that is divided into one or three or more parts may be interposed. In the illustrated example, the first central mechanism housing 13 and the second central mechanism housing 14 are made of aluminum die-cast. Alternatively, the first central mechanism housing 13 and the second central mechanism housing 14 may be made of a lightweight material such as magnesium die-cast.

[0076] In the illustrated configuration, a convex portion 31b is provided that protrudes radially outward from the side surface of the linear motion member 31, and grooves 32a, 32b that engage with the convex portion 31b are provided on the outer peripheral surface of the power conversion ring 32. Alternatively, for example, a groove may be provided on the side surface of the linear motion member 31, and a convex portion that protrudes radially outward from the outer peripheral surface of the power conversion ring 32 may be provided.

[0077] The feed screw mechanism 25 has been 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. [Explanation of symbols]

[0078] 1…Pipe diameter expansion tool 2...Cap, 2a...Jaw support groove, 2b...Female thread 3...Wedge 4... jaw, 4a... ring receiving groove, 4b... engagement recess, 4c... ring 5. Grip 6...switch lever, 6a...switch body 7...expanded diameter portion, 7a...battery mounting portion 8...Battery 10...Tool body 11...Main body housing, 11a...Slot 12...Front mechanism housing, 12a...male thread, 12b...engaging part, 12c...rectangular projecting part 12d... rotation restriction portion, 12e... through hole 13...first central mechanism housing, 13a, 13b...engagement portions, 13c...boss portion 13d...recessed portion, 13e...inner peripheral surface, 13f...through hole 14... second central mechanism housing, 14a, 14b... engagement portions, 14c... boss portion 14d...recessed portion, 14e...inner peripheral surface, 14f...through hole 15... rear mechanism housing, 15a... front surface, 15b... engagement portion, 15c... boss portion 15d...Screw hole 16...Volts 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 thread member, 27a... gear, 27b... female thread, 27c, 27d... female thread member bearing 27e...Thrust bearing, 27f...Washer 28...screw shaft, 28a...male thread, 28b...ball 29...screw shaft guide, 29a...support member, 29b...roller, 29c...rail 30...Jaw rotation mechanism 31... Linear moving member, 31a... Female screw, 31b... Convex portion, 31c... Roller 32... power conversion ring, 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...recessed groove 34d...Through hole 35... second rotation drive ring, 35a... engagement protrusion, 35b... meshing teeth, 35c... compression spring 35d...spring receiving portion, 35e...insertion hole 36... third rotation drive ring, 36a... meshing teeth, 36b... engaging protrusion, 36c... insertion hole 41...Initial position sensor 42...End position sensor 43...Magnet 44...Position adjustment mechanism, 44a...Operation unit 45...Controller J: Motor axis K...screw shaft axis

Claims

1. A pipe diameter expanding tool for expanding the diameter of an end of a synthetic resin fluid pipe, an electric motor housed in a main body housing; a screw shaft provided in the main body housing so as to be movable in the front-rear direction in parallel with or along the axis of the output shaft of the electric motor; A female screw member that is threadedly engaged with the screw shaft and rotates around the axis of the screw shaft to move the screw shaft back and forth; a gear that meshes with the female screw member to transmit rotation of the output shaft of the electric motor; a wedge extending forward from the screw shaft; a plurality of jaws connected to the main body housing so as to be openable and closable and to be pushed by the wedge when the wedge advances together with the screw shaft, and to be opened radially outward relative to each other; a cap that supports the plurality of jaws so that they can be opened and closed and that restricts the forward and backward movements of the plurality of jaws; a front mechanism housing, a central mechanism housing, and a rear mechanism housing, which are arranged in this order from front to rear within the main body housing; a bolt for connecting the front mechanism housing and the rear mechanism housing; the front mechanism housing engages with the cap to restrict forward movement of the cap; the rear mechanism housing restricts rearward movement of the rear end of the female screw member, The central mechanism housing has a through hole through which the bolt passes in the front-rear direction.

2. The tube expanding tool according to claim 1, a grip extending downward from the main body housing; the grip is provided between the electric motor and the plurality of jaws in the front-rear direction, A pipe expanding tool in which the electric motor is disposed below the screw shaft.

3. The tube expanding tool according to claim 2, A pipe expanding tool in which at least a portion of the screw shaft and the grip overlap in the front-to-rear direction.

4. The tube expanding tool according to any one of claims 1 to 3, A tube expanding tool, wherein a planetary reduction mechanism that reduces the output of the output shaft is provided between the output shaft of the electric motor and the screw shaft.

5. The tube expanding tool according to any one of claims 1 to 4, a rotary drive ring coupled to the rear of the plurality of jaws; a jaw rotation mechanism that rotates the rotary drive ring by an output of the electric motor to rotate the plurality of jaws in a circumferential direction; A pipe expanding tool, wherein the rotary drive ring is provided in front of the female thread member.

6. The tube expanding tool according to any one of claims 1 to 5, the front mechanism housing and the rear mechanism housing are made of iron; A tube expanding tool in which the central mechanism housing is formed of a material lighter than steel.

7. The tube expanding tool according to claim 6, a second central mechanism housing between the central mechanism housing and the rear mechanism housing; A tube expanding tool in which the front mechanism housing, the central mechanism housing, the second central mechanism housing, and the rear mechanism housing have engagement portions at each end where adjacent ends overlap each other in the front-to-rear direction.

8. The tube expanding tool according to claim 7, A spindle 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 a spindle bearing that rotatably supports the spindle and a female thread member bearing that rotatably supports the female thread member.

9. A tube expanding tool according to any one of claims 6 to 8, The rear mechanism housing is a pipe expanding tool that supports a thrust bearing that abuts against the rear end of the female thread member.

10. A tube expanding tool according to any one of claims 1 to 9, A pipe expanding tool in which a ball is interposed in the threaded portion between the screw shaft and the female thread member.

Images