Pipe expanding tool

Abstract

To provide pipe expanding tool that can fit a cap with multiple jaws to its regular position against the main housing.SOLUTION: The pipe expanding tool 1 for expanding the end of a synthetic resin fluid pipe has a threaded shaft 27 extending in the front-back direction in the main housing 11, and a female thread member 26 that is screwed onto the threaded shaft 27 and rotates around the axis of the threaded shaft 27, causing the threaded shaft 27 to move back and forth. The pipe widening tool 1 has a plurality of jaws 4 that are pushed by a wedge 3 on the front of the threaded shaft 27 to open each other radially outward, and a cap 2 that supports the plurality of jaws 4 allowing them to open and close radially and is removably attached to the main housing 11. The pipe widening tool 1 has a receiving cam 51 that is movable in the front-back direction and rotatable around the axis of the threaded shaft 27 together with the plurality of jaws 4 by engaging with the rear surface of the plurality of jaws 4. The pipe widening tool 1 has a coil spring 52 that forces the receiving cam 51 forward.SELECTED DRAWING: Figure 7

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 plastic pipe. Pipe expansion tools have been available to expand the inner diameter of the end of a PEX pipe. The end of the PEX pipe is expanded using the pipe expansion tool, and the expanded part is 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 by 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 pipe expanding tool has a substantially conical wedge, a screw shaft connected to the rear of the wedge and extending in the front-to-rear direction, and multiple jaws arranged in the circumferential direction of the wedge in front of the wedge. The multiple jaws are supported by a cap attached to the front of a main housing so that they can be opened and closed radially. The screw shaft is prevented from rotating relative to the main housing. The screw shaft is threadedly engaged with a female thread member supported by the main housing so that it can rotate around the axis of the screw shaft.

[0004] When the female screw member is rotated by driving an electric motor, the screw shaft, which is prevented from rotating, moves back and forth. As the wedge advances with the screw shaft, the jaws are pushed by the wedge and open radially outward relative to each other. By opening the jaws radially outward while the jaws are inserted into the end opening of the PEX pipe, the end of the PEX pipe can be widened. As the wedge retreats with the screw shaft, the jaws are released from the pressing force of the wedge and close radially inward.

[0005] For example, if the pipe expansion tool has six jaws, the end of the PEX pipe is subjected to a radially outward opening force from each of the jaws at six equally spaced locations around the circumference. Therefore, in one expansion operation, the end of the PEX pipe is expanded into a roughly hexagonal shape. The pipe expansion tool has a jaw rotation mechanism that rotates the jaws circumferentially around the wedge to expand the end of the PEX pipe into a cylindrical shape. The jaw rotation mechanism is driven by an electric motor to rotate the jaws at a predetermined angle (e.g., 15°) and in a predetermined direction (e.g., counterclockwise when viewed from the front). The expansion operation of the jaws by moving the screw shaft and the rotation of the jaws by the jaw rotation mechanism are alternately repeated. Therefore, the position at which each jaw contacts the inner surface of the PEX pipe moves sequentially around the circumference. As a result, the end of the PEX pipe is uniformly expanded and approaches a cylindrical shape.

[0006] PEX pipes are commonly available in multiple sizes, such as nominal diameters of 0.5 inches, 0.75 inches, 1 inch, and 1.5 inches. The larger the PEX pipe size, the greater the force required to expand the end of the PEX pipe. Therefore, it is desirable to use multiple types of jaws to accommodate different sizes of PEX pipe. For example, a first cap with multiple jaws having a first radial thickness and a second cap with multiple jaws having a second radial thickness greater than the first thickness are selected and attached. The first and second caps are removably attached to the main housing by, for example, threaded engagement.

[0007] The rotational power is transmitted from the jaw rotation mechanism to each jaw by, for example, providing a concave-convex shape on each engaging portion, which then engages with each other to rotate the jaws together. When attaching a cap to the main housing, the engaging portions may not engage properly. For example, the cap may be attached to the main housing with the convex portion on the jaw rotation mechanism interfering with the convex portion on the jaw in the forward / backward direction. In this case, the cap cannot be attached to the rearmost position, and the operator may mistakenly believe that the cap is attached to the rearmost position even though it actually stops further forward than the rearmost position.

[0008] In some cases, an operator may mistakenly believe that the cap is properly attached to the rearmost position when the jaw rotation mechanism's engaging portion and each jaw's engaging portion are not properly engaged. In this case, the jaws may not open to the required radial position or may not rotate circumferentially to the required position. This can cause the tube expansion tool to malfunction. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] US Patent Application Publication No. 2020 / 0261959 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, there is a need for a tube expanding tool that can properly install a cap having multiple jaws onto a main housing. [Means for solving the problem]

[0011] According to one feature of the present disclosure, a pipe expanding tool for expanding the diameter of an end of a synthetic resin fluid pipe has a threaded shaft extending in the forward and backward directions within a main housing. The pipe expanding tool has an internally threaded member that is threadedly engaged with the threaded shaft and rotates around the axis of the threaded shaft to move the threaded shaft forward and backward. The pipe expanding tool has multiple jaws that open radially outward relative to one another when pressed by wedges provided at the front of the threaded shaft. The pipe expanding tool has a cap that supports the multiple jaws so that they can be opened and closed radially and is removably attached to the main housing. The pipe expanding tool has a receiving cam that is movable in the forward and backward directions and engages with the rear surfaces of the multiple jaws so that it can rotate together with the multiple jaws around the axis of the threaded shaft. The pipe expanding tool has a biasing member that biases the receiving cam forward.

[0012] Therefore, when a cap with multiple jaws is attached to the main housing, the receiving cam can move rearward. This reduces interference between the receiving cam and the rear surfaces of the multiple jaws in the front-to-rear direction. This allows the cap to be attached to the main housing to its correct rearmost position without stopping before the rearmost position. After the cap is attached to its rearmost position, the receiving cam can be rotated around the screw shaft relative to the multiple jaws to properly engage the forward-biased receiving cam with the rear surfaces of the multiple jaws. This allows rotational power to be transmitted from the receiving cam 51 to the multiple jaws 4. [Brief explanation of the drawings]

[0013] [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 from which the body housing has been removed, viewed from the front right side. [Figure 3] FIG. [Figure 4] FIG. 2 is a perspective view of the tool body from which the body housing has been removed, viewed from the rear right side. [Figure 5] FIG. 10 is a perspective view of the tool body from which the body housing has been removed, viewed from the rear left, showing a state in which the screw shaft is positioned at a rear end position. [Figure 6] FIG. 10 is a perspective view of the tool body from which the body housing has been removed, viewed from the rear left, showing a state in which the screw shaft is positioned at a front end position. [Figure 7] FIG. 4 is a vertical cross-sectional view of the tool body as viewed from the right, showing a state in which the screw shaft is located at a rear end position. [Figure 8] FIG. 4 is a vertical cross-sectional view of the tool body as viewed from the right, showing a state in which the screw shaft is located at a front end position. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 7. [Figure 10] 9 is a cross-sectional view taken along the line XX in FIG. 8. [Figure 11] 10 is a cross-sectional view taken along line XI-XI in FIG. 7. [Figure 12] 12 is a cross-sectional view taken along the line XII-XII in FIG. 11. [Figure 13] 12 is a cross-sectional view taken along line XII-XII in FIG. 11, showing a state in which the screw shaft is positioned at a front end position. [Figure 14] FIG. 10 is a top view of a rotating gear, a receiving cam, and multiple jaws. DETAILED DESCRIPTION OF THE INVENTION

[0014] According to another feature of the present disclosure, the tube expanding tool has a rotary gear that engages with the receiving cam and rotates the receiving cam about the axis of the screw shaft to rotate the multiple jaws about their axes. Therefore, when the receiving cam and the rear surfaces of the multiple jaws are properly engaged, the receiving cam is biased forward, allowing the rotational power of the rotary gear to be efficiently transmitted to the multiple jaws via the receiving cam. When the receiving cam and the rear surfaces of the multiple jaws are not properly engaged, the engagement between the receiving cam and the rear surfaces of the multiple jaws can be restored to the normal state by moving the receiving cam backward against the biasing force.

[0015] According to another feature of the present disclosure, the rotating gear has a cylindrical wall through which the screw shaft and / or wedge is inserted. The rotating gear has a spring receiving portion extending radially inward from the cylindrical wall. The receiving cam is cylindrical, through which the screw shaft and / or wedge is inserted, and is disposed coaxially with the rotating gear. The biasing member is a coil spring disposed between the rotating gear and the receiving cam. The biasing member is disposed on the inner periphery of the rotating gear, and its rear portion abuts against the spring receiving portion. Therefore, the biasing member can be compactly housed radially inside the cylindrical wall of the rotating gear. This allows the outer peripheral regions of the rotating gear and the receiving cam to be made compact. This allows the pipe expansion tool to be provided compactly, improving the workability of, for example, expanding the end of a PEX pipe installed in a narrow space. Furthermore, the receiving cam is biased forward with a substantially uniform force at all circumferential locations. This prevents the receiving cam from tilting relative to the screw shaft. This allows the receiving cam to move smoothly back and forth.

[0016] According to another feature of the present disclosure, the main housing includes a bearing that slidably supports the outer peripheral surface of the cylindrical wall of the rotating gear. This allows the rotating gear to rotate precisely around the axis of the threaded shaft while minimizing the size of the main housing. This allows the diameters of the ends of PEX pipes installed in various locations to be expanded and the PEX pipe ends to be expanded into a uniform cylindrical shape.

[0017] According to another feature of the present disclosure, the rotating gear is provided with a guide having a convex or concave shape in the front-rear direction. The receiving cam is provided with a guide engagement portion that engages with the guide so as to be movable in the front-rear direction. The guide and the guide engagement portion allow the receiving cam to move back and forth relative to the rotating gear, and the rotating gear rotates the receiving cam around the axis of the screw shaft. This reduces loss of rotational power transmitted from the rotating gear to the receiving cam and prevents the receiving cam from moving up and down or left and right. This reduces excess energy loss when rotating multiple jaws around the axis of the screw shaft. Furthermore, for example, even when the biasing member is in a natural length state where it does not bias the receiving cam, the rotating gear and the receiving cam can rotate together. This reduces fatigue damage to the biasing member.

[0018] According to another feature of the present disclosure, the biasing member is provided between the rotary gear and the receiving cam. The biasing member, the rotary gear, and the receiving cam rotate integrally around the axis of the screw shaft. Therefore, when the rotary gear and the receiving cam are rotated around the axis of the screw shaft, accumulation of compression energy or expansion energy in the biasing member can be suppressed. This can prevent excessive energy loss in the biasing member. Furthermore, reducing the repetition of compression and expansion of the biasing member can prevent fatigue failure of the biasing member.

[0019] According to another feature of the present disclosure, the front surface of the receiving cam is provided with a cam engagement portion that is convex or concave in the front-to-rear direction. Each of the rear surfaces of the multiple jaws is provided with a jaw engagement portion that is concave or convex in the front-to-rear direction and engages with the cam engagement portion. The receiving cam can be moved rearward against the biasing member by at least the front-to-rear length of the cam engagement portion. Therefore, even when the front surface of the receiving cam and the rear surface of each jaw are in maximum interference with each other, i.e., when the most protruding portion of the cam engagement portion and the most protruding portion of the rear surface of each jaw are in contact with each other in the front-to-rear direction, the cam engagement portion and the jaw engagement portion can be returned to their normal engagement state by moving the receiving cam rearward. This allows the cap to be attached to the rearmost position.

[0020] According to another feature of the present disclosure, the rotary gear has a stopper that abuts against the rear end of the wedge to prevent the wedge from moving abnormally rearward. Therefore, providing the stopper on the rotary gear ensures the strength of the stopper. This prevents high loads from being applied to other components that engage with the screw shaft, such as a feed screw mechanism that moves the screw shaft back and forth.

[0021] According to another feature of the present disclosure, the rotary gear has a cylindrical wall through which the wedge is inserted. The stopper extends radially inward from the cylindrical wall. The biasing member is disposed on the inner circumferential side of the rotary gear. The rear portion of the biasing member abuts against the stopper. Therefore, when the rear portion of the biasing member abuts against the stopper, the biasing member generates a biasing force that biases the receiving cam forward. The stopper serves both as a support portion for the biasing member and a member that restricts movement of the wedge, allowing the rotary gear to be compactly provided. Moreover, by disposing the biasing member on the inner circumferential side of the rotary gear, the biasing member can be accommodated compactly. Thus, the main housing can be compactly provided.

[0022] 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 efficiency of power transmission from the female screw member to the screw shaft. As a result, the rotational drive of the female screw member can be efficiently converted into back and forth movement of the screw shaft.

[0023] Next, one embodiment of the present disclosure will be described with reference to Figures 1 to 14. As shown in Figure 1, the pipe expanding tool 1 of this embodiment has a tool body 10 housed in a main body housing 11, and a grip 5 extending downward from the bottom of the main body housing 11. A user is positioned approximately at the rear of the pipe expanding 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 to the side in front of the user is referred to as the front. Up, down, left, and right directions are based on the user.

[0024] As shown in Figures 1, 7, and 12, a ring-shaped cap 2 is attached to the front of the tool body 10. A cylindrical screw shaft 27 extending in the front-rear direction is provided in the center of the tool body 10. A generally conical wedge 3 is attached to the front end of the screw shaft 27. The wedge 3 is located radially inward of the cap 2. The screw shaft 27 and the wedge 3 are arranged on a screw shaft axis K extending in the front-rear direction at the center of the tool body 10. The screw shaft 27 and the wedge 3 are movable in the front-rear direction along the screw shaft axis K between a rear end position and a front end position. A plurality of jaws 4 extending in the front-rear direction are provided radially outward of the wedge 3 and radially inward of the cap 2. The plurality of jaws 4 are arranged at equal intervals around the wedge 3. The pipe expanding tool 1 has, for example, six jaws 4, each arranged at 60° intervals around the wedge 3. The jaws 4 are radially openable and closable between a closed position where they are in close contact with each other in the circumferential direction to cover the wedge 3 and an open position where they are open radially outward from each other to expose the tip of the wedge 3 .

[0025] 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 body 6a is provided inside the grip 5 and can be 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. When using the pipe expansion tool 1, a user holds the grip 5 and inserts the multiple jaws 4 into the end of a PEX pipe made of synthetic resin. Pulling the switch lever 6 opens and closes the multiple jaws 4 radially, thereby expanding the end of the PEX pipe to a predetermined diameter. A roughly rectangular box-shaped bulge 7 that expands in the front-to-back and left-to-right directions is provided at the bottom of the grip 5. The bulge 7 houses a controller 9. The controller 9 includes a shallow rectangular box-shaped case and a resin-molded control board housed within the case. The controller 9 is housed in the bulging portion 7 in a position where its thickness direction (the direction in which the shortest side of the case extends) is aligned with the vertical direction. The controller 9 mainly controls the driving of the electric motor 20, which will be described later.

[0026] As shown in FIG. 1, a battery mounting portion 7a is provided on the underside of the bulge 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. 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 with a separately prepared 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 20.

[0027] As shown in FIG. 7 , the main body housing 11 includes an outer case 17 that covers the outer periphery of the tool body 10, and a front mechanism housing 12, a first central mechanism housing 13, a second central mechanism housing 14, and a rear mechanism housing 15 that are assembled together within the outer case 17. The front mechanism housing 12, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 are housed within the outer case 17 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 generally cylindrical with a hollow passage running through them in the front-to-rear direction. The rear mechanism housing 15 is plate-shaped with its thickness extending 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. A gear shaft 23, an idle gear 24, and an internally threaded member 26, which will be described later, are housed within the mechanism housing.

[0028] 2 and 3, a male thread 12a is provided on the outer peripheral surface of the front portion 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 rear portion of the cap 2. The male thread 12a screws into the female thread 2b, connecting the cap 2 to the front portion of the front mechanism housing 12.

[0029] As shown in Figures 2 and 3, the outer peripheral surface of the front mechanism housing 12 is provided with a flange 12e, which has a generally rectangular shape that protrudes radially outward and has four screw holes that penetrate in the front-to-rear direction at each corner. The outer peripheral surfaces of the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 are each provided with four bosses 13f, 14h, and 15b, which have a generally cylindrical shape that protrudes radially outward and has through-holes that penetrate in the front-to-rear direction. By lining up the bosses 13f, 14h, and 15b behind the flange 12e in the front-to-rear direction, the screw holes in the flange 12e and the through-holes in each boss are communicated in the front-to-rear direction. Four bolts 16 are inserted from rear to front through each of the communicating through-holes and fastened to the screw holes in the flange 12e. This connects the front mechanism housing 12, the first central mechanism housing 13, the second central mechanism housing 14, and the rear mechanism housing 15 in a line-up in the front-to-rear direction.

[0030] As shown in FIGS. 2 and 3, the first central mechanism housing 13 has a downward extending portion 13b with a generally U-shaped outer shape that extends downward from the cylindrical shape. The second central mechanism housing 14 has a downward extending portion 14b with a generally U-shaped outer shape that extends downward from the cylindrical shape. The downward extending portions 13b and 14b are connected in the front-to-rear direction to form a space for accommodating the gear shaft 23 and the idle gear 24. The downward extending portion 13b has two through-holes that penetrate in the front-to-rear direction, arranged side by side in the front and rear. The lower through-hole has a recess 13c for supporting the gear shaft 23, which will be described later. The upper through-hole 13d is press-fitted with a shaft member 24a that supports the idle gear 24. The downward extending portion 14b has two through-holes that penetrate in the front-to-rear direction, arranged side by side in the front and rear. The lower through-hole has a recess 14c for supporting the gear shaft 23. The shaft member 24a is inserted into the upper through-hole 14d.

[0031] As shown in FIG. 7 , a generally cylindrical electric motor 20 is housed in the lower rear portion of the exterior case 17. For example, a motor called a DC brushless motor is used as the electric motor 20. The electric motor 20 is located below the screw shaft 27 located at the rear end position and above the grip 5. A motor shaft 20a of the electric motor 20 extends in the front-rear direction along the motor axis J and parallel to the screw shaft axis K that passes through the center of the screw shaft 27. The motor shaft 20a is supported by bearings 20e and 20f held in the exterior case 17 so as to be rotatable about the motor axis J.

[0032] As shown in FIG. 7, the electric motor 20 has a stator 20b that is supported non-rotatably relative to the outer case 17. The stator 20b is disposed radially outward from the motor shaft 20a. The rotor 20c of the electric motor 20 is attached to the motor shaft 20a on the inner circumferential side of the stator 20b so as to be rotatable integrally with the motor shaft 20a. A rotation speed detection sensor 20d is provided in front of the rotor 20c. The rotation speed detection sensor 20d detects the rotation speed of the motor shaft 20a by detecting the rotation angle of the rotor 20c. A fan 21 for introducing cooling air into the electric motor 20 is attached integrally to the motor shaft 20a between the rotor 20c and the rear bearing 20f in the front-to-rear direction. When the fan 21 rotates together with the motor shaft 20a, cooling air flows from the front to the rear of the electric motor 20.

[0033] As shown in Figure 7, a planetary reduction mechanism 22 for reducing the output of the motor shaft 20a is provided in front of the electric motor 20. The planetary reduction mechanism 22 is housed in the exterior case 17 and aligned with the electric motor 20 in the front-rear direction. The rotational drive of the motor shaft 20a is reduced in two stages by the planetary reduction mechanism 22 and transmitted to the gear shaft 23.

[0034] As shown in Figure 7, the gear shaft 23 is supported by bearings 23b and 23c so as to be rotatable around the motor axis J. The front bearing 23b is press-fitted into a recess 13c of the first central mechanism housing 13. The rear bearing 23c is press-fitted into a recess 14c of the second central mechanism housing 14. The gear shaft 23 has a drive gear 23a between the bearings 23b and 23c in the front-to-rear direction. The drive gear 23a rotates integrally with the gear shaft 23 around the motor axis J.

[0035] 7, an idle gear 24 is provided between the gear shaft 23 and the screw shaft 27 in the vertical direction. The idle gear 24 is supported by a cylindrical shaft member 24a extending in the front-rear direction so as to be rotatable around the axis of the shaft member 24a. The idle gear 24 meshes with the lower driving gear 23a and also meshes with the upper driven gear 26a.

[0036] As shown in FIG. 7 , 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 27 and a female screw member 26. A male screw 27a is provided on the outer peripheral surface of the screw shaft 27. The female screw member 26 is formed in a generally cylindrical shape that circumferentially covers the screw shaft 27. A female screw 26b is provided on the inner peripheral surface of the female screw member 26. The female screw 26b is threadedly engaged with the male screw 27a of the screw shaft 27 via a plurality of balls 27b. A driven gear 26a that protrudes radially outward and meshes with the idle gear 24 is provided on the outer periphery of the female screw member 26. The rotational drive of the gear shaft 23 is reduced and transmitted to the female screw member 26 by the meshing between the drive gear 23a and the idle gear 24 and the meshing between the idle gear 24 and the driven gear 26a.

[0037] As shown in Figure 7, the female thread member 26 is supported rotatably about the screw shaft axis K by bearings 26c and 26d housed in the tool body 10. The front bearing 26c is press-fitted into the inner circumferential surface 13a of the first central mechanism housing 13. The rear bearing 26d is press-fitted into the inner circumferential surface 14a of the second central mechanism housing 14. A thrust bearing 26e is provided between the rear surface of the female thread member 26 and the front surface 15a of the rear mechanism housing 15 to bear the thrust load that pushes the female thread member 26 rearward.

[0038] As shown in Figures 4 and 5, a screw shaft guide 28 is attached to the rear of the screw shaft 27 to prevent rotation of the screw shaft 27 and to guide the forward and backward movement of the screw shaft 27. The screw shaft guide 28 has a roller shaft 28a connected to the rear end of the screw shaft 27 and extending in the left-right direction. Rollers 28b are provided on both left and right ends of the roller shaft 28a. A pair of loop-shaped rails 28c extending in the front-back direction are attached to the left and right sides of the second central mechanism housing 14. The rollers 28b engage with the rails 28c and are movable in the front-back direction along the rails 28c. The screw shaft 27 moves in the front-back direction together with the screw shaft guide 28, guided by the rollers 28b.

[0039] 5, 6, 12, and 13, the tool body 10 has a jaw rotation mechanism 30 that rotates the multiple jaws 4. The multiple jaws 4 are rotated around the screw shaft axis K by the jaw rotation mechanism 30. The jaw rotation mechanism 30 has a push plate 34 that moves back and forth in conjunction with the rotation of the motor shaft 20a, and a shaft 31 that rotates around its axis in conjunction with the back and forth movement of the push plate 34.

[0040] As shown in Figures 3 and 4, the jaw rotation mechanism 30 has a ball retainer 35 attached to the shaft 31. The ball retainer 35 is movable in the front-to-rear direction along the extension direction of the shaft 31. A guide shaft 41 extending parallel to the shaft 31 is provided to the right of the shaft 31. A cylindrical guide shaft support portion 14e that protrudes rearward is provided on the downward extension portion 14b of the second central mechanism housing 14. A female thread that penetrates in the front-to-rear direction is provided in the center of the guide shaft support portion 14e. The guide shaft 41 is fixed to the second central mechanism housing 14 by threading a male thread at its tip into the female thread of the guide shaft support portion 14e.

[0041] As shown in FIG. 3 , the ball retainer 35 has a substantially cylindrical sleeve mounting portion 35a and a lateral extension portion 35d that extends to the right of the sleeve mounting portion 35a. A shaft insertion hole 35c that penetrates in the front-to-rear direction is provided in the center of the sleeve mounting portion 35a. The shaft 31 is inserted into the shaft insertion hole 35c so as to be slidable in the front-to-rear direction. A through hole 35e that penetrates in the front-to-rear direction is provided in the lateral extension portion 35d. A guide shaft 41 is inserted into the through hole 35e so as to be slidable in the front-to-rear direction. Thus, the ball retainer 35 is guided by the shaft 31 and the guide shaft 41 so as to be slidable in the front-to-rear direction and restricts rotation of the shaft 31 around its axis.

[0042] As shown in FIGS. 4 to 6 , the push plate 34 is formed in a plate shape and is attached integrally to the roller shaft 28a with its thickness aligned in the front-to-rear direction. The push plate 34 extends downward from the roller shaft 28a and is disposed rearward of the sleeve mounting portion 35a. The push plate 34 has a through hole 34a penetrating in the front-to-rear direction. The shaft 31, which protrudes rearward from the sleeve mounting portion 35a, is inserted into the through hole 34a. The push plate 34 moves forward and backward integrally with the screw shaft 27. When the screw shaft 27 moves forward, the push plate 34 presses the rear surface of the ball retainer 35 forward. When the screw shaft 27 moves backward, the push plate 34 moves away from the ball retainer 35. Therefore, the push plate 34 does not exert a force that moves the ball retainer 35.

[0043] As shown in FIG. 3, the sleeve mounting portion 35a is provided with ball retaining holes 35b that penetrate in the left-right direction and communicate with the shaft insertion hole 35c. Balls 38 are inserted into the pair of left and right ball retaining holes 35b, respectively. A sleeve 36 that covers the pair of balls 38 and the ball retaining holes 35b from the radially outer side is mounted in the sleeve mounting portion 35a. By mounting the sleeve 36 in the sleeve mounting portion 35a, the pair of balls 38 are held in place so that they do not come off the ball retaining holes 35b. The pair of balls 38 are located on the left and right sides of the shaft 31. The ball retainer 35 is prevented from rotating, restricting movement of the pair of balls 38 around the axis of the shaft 31. A nut 37 for holding the sleeve 36 is mounted in the front portion of the sleeve mounting portion 35a.

[0044] 3, 12, and 13, the shaft 31 is formed by assembling a front shaft 32 and a rear shaft 33 in the front-to-rear direction. The front shaft 32 is supported by a shaft support portion 13e of the first central mechanism housing 13 so as to be rotatable about its axis. The rear shaft 33 is supported by a shaft support portion 14g of the second central mechanism housing 14 so as to be rotatable about its axis. The rear shaft 33 is inserted into a ball retainer 35. A male thread 33a is provided at the front portion of the rear shaft 33. A female thread 32a that threadably mates with the male thread 33a is provided at the rear portion of the front shaft 32. The front shaft 32 and the rear shaft 33 are attached together by threading the female thread 32a into the male thread 33a.

[0045] As shown in Figures 3, 12, and 13, a pair of ball grooves 33b is provided on the outer circumferential surface of the rear shaft 33. The ball grooves 33b extend generally in the longitudinal direction of the rear shaft 33 and also extend circumferentially from the rear to the front like a screw groove. The ball grooves 33b extend from the rear to the front in the direction of the second rotation R2 (see Figure 6). The pair of ball grooves 33b are arranged in a point-symmetrical positional relationship with respect to the axial center of the rear shaft 33. Balls 38 that protrude radially inward from the ball retaining holes 35b of the ball retainer 35 into the shaft insertion holes 35c engage with each ball groove 33b.

[0046] As shown in Figures 5 and 6, when the ball retainer 35 moves back and forth relative to the rear shaft 33, the pair of balls 38 (see Figure 3) move within the ball groove 33b along the extension direction of the ball groove 33b. Because the pair of balls 38 do not move around the axis of the rear shaft 33, the rear shaft 33 rotates around its axis relative to the ball retainer 35, which moves back and forth. When the ball retainer 35 moves forward, the rear shaft 33 rotates in the direction of a first rotation R1 relative to the ball retainer 35. When the ball retainer 35 moves backward, the rear shaft 33 rotates in the direction of a second rotation R2 relative to the ball retainer 35. The front shaft 32, which is threadedly engaged with the rear shaft 33, rotates around its axis integrally with the rear shaft 33.

[0047] 12 and 13, a flange-shaped spring bearing portion 14f that protrudes radially is provided on the shaft support portion 14g of the second central mechanism housing 14. A compression spring 39 that urges the ball retainer 35 rearward is interposed between the spring bearing portion 14f and the ball retainer 35 in the front-rear direction.

[0048] As shown in FIGS. 11 to 13, the jaw rotation mechanism 30 has a cylindrical one-way clutch 42 and a drive-side gear 43. The one-way clutch 42 and the drive-side gear 43 are attached to the front portion of the front shaft 32, in front of the shaft support portion 13e. The one-way clutch 42 is disposed radially between the front shaft 32 and the drive-side gear 43. The one-way clutch 42 has a structure known as a sprag type, for example, and transmits rotation only in one direction from the radially inner peripheral surface side to the radially outer peripheral surface side. The one-way clutch 42 transmits the second rotation R2 (see FIG. 6) of the front shaft 32 to the drive-side gear 43. The one-way clutch 42 does not transmit the first rotation R1 (see FIG. 5) of the front shaft 32 to the drive-side gear 43, causing the front shaft 32 to rotate freely.

[0049] 5 and 6 , a two-flat width portion 32b having a pair of flat surfaces extending parallel to each other in the front-rear direction is provided at the rear of the front shaft 32. The two-flat width portion 32b is disposed between the first central mechanism housing 13 and the second central mechanism housing 14 in the front-rear direction, in a position exposed to the outside of the first central mechanism housing 13 and the second central mechanism housing 14. A two-flat width portion 33c having a pair of flat surfaces extending parallel to each other in the front-rear direction is provided at the rear end of the rear shaft 33. With the two-flat width portion 32b held with a wrench or the like to prevent the front shaft 32 from rotating, the rear shaft 33 can be screwed onto the front shaft 32 by holding the two-flat width portion 33c with a wrench or the like.

[0050] As shown in Figures 3, 9, and 10, the jaw rotation mechanism 30 has a generally cylindrical rotary gear 50 and a generally cylindrical receiving cam 51. The rotary gear 50 is disposed in front of the female thread member 26. The receiving cam 51 is disposed in front of the rotary gear 50. The rotary gear 50 and the receiving cam 51 are coaxially rotatably supported by the inner circumferential surface of the front mechanism housing 12. The front mechanism housing 12 has a first inner circumferential surface 12b and a second inner circumferential surface 12c, which are cylindrical inner circumferential surfaces centered on the screw shaft axis K. The first inner circumferential surface 12b and the second inner circumferential surface 12c are arranged side by side and communicate with each other from the front to the rear. The second inner circumferential surface 12c is located in front of the first inner circumferential surface 12b and has a smaller diameter than the first inner circumferential surface 12b. The front end of the first inner circumferential surface 12b and the rear end of the second inner circumferential surface 12c are connected by a radially extending surface 12d.

[0051] As shown in Figures 3, 12, and 13, the rotating gear 50 has a cylindrical wall 50b and a driven gear 50a that protrudes radially from the rear of the cylindrical wall 50b. An insertion hole 50c is provided in the center of the cylindrical wall 50b, penetrating in the front-rear direction. The insertion hole 50c has a diameter large enough to allow the screw shaft 27 to pass through and move the screw shaft 27 and the wedge 3 in the front-rear direction. The outer peripheral surface of the cylindrical wall 50b slides against the first inner peripheral surface 12b of the front mechanism housing 12, thereby rotating around the screw shaft axis K. Therefore, in this disclosure, the first inner peripheral surface 12b corresponds to a bearing that slidably supports the outer peripheral surface of the cylindrical wall 50b. The driven gear 50a meshes with the driving gear 43 behind the first inner peripheral surface 12b. The rotational power of the driving gear 43 is transmitted to the driven gear 50a at a reduced speed. When the driving gear 43 rotates in the direction of the second rotation R2 (see FIG. 6), the driven gear 50a rotates counterclockwise as viewed from the front. When the driving gear 43 rotates in the direction of the first rotation R1 (see FIG. 5), the driven gear 50a rotates clockwise as viewed from the front.

[0052] As shown in Figures 12 and 13, the rotary gear 50 has a spring bearing portion 50d extending radially inward from the rear portion of the cylindrical wall 50b. The spring bearing portion 50d is located radially inward of the driven-side gear 50a. The inner circumferential surface of the spring bearing portion 50d is sized to allow the screw shaft 27 to pass through but not the rear end 3a of the wedge 3. The rear portion of a coil spring 52 (described later) abuts against the front surface of the spring bearing portion 50d. The spring bearing portion 50d also serves as a stopper that prevents the screw shaft 27 from moving abnormally rearward. Normally, when the screw shaft 27 moves backward, the rear end 3a of the wedge 3 is located forward of the spring bearing portion 50d. Even if the screw shaft 27 attempts to move further rearward than the rear end position, the rear end 3a of the wedge 3 abuts against the front surface of the spring bearing portion 50d, stopping the rearward movement of the screw shaft 27.

[0053] 3 and 14, the rotary gear 50 has a generally rectangular guide 50e that protrudes forward from the front surface of the cylindrical wall 50b. Two guides 50e are provided at 180° intervals around the circumference of the cylindrical wall 50b. The guides 50e guide the receiving cam 51 so that it does not rotate relative to the rotary gear 50 and moves back and forth.

[0054] As shown in Figures 3, 12 to 14, the receiving cam 51 has a cylindrical portion 51a. The outer peripheral surface of the cylindrical portion 51a slides against the second inner peripheral surface 12c of the front mechanism housing 12, thereby rotating around the screw shaft axis K. An insertion hole 51b penetrating in the front-to-rear direction is provided in the center of the cylindrical portion 51a. The insertion hole 51b has a diameter that allows the screw shaft 27 and the wedge 3 to be inserted therethrough. A second spring bearing portion 51c that protrudes radially outward in a flange-like shape is provided at the rear of the cylindrical portion 51a. The outer peripheral surface of the second spring bearing portion 51c has approximately the same diameter as the outer peripheral surface of the cylindrical wall 50b of the rotary gear 50. The outer peripheral surface of the second spring bearing portion 51c slides against the first inner peripheral surface 12b of the front mechanism housing 12, thereby rotating around the screw shaft axis K. A coil spring (biasing member) 52 is interposed between the spring bearing portion 50d of the rotating gear 50 and the second spring bearing portion 51c of the receiving cam 51. The receiving cam 51 is biased forward with respect to the rotating gear 50 by the coil spring 52. The biasing direction of the receiving cam 51 by the coil spring 52 is along the extension direction of the screw shaft axis K.

[0055] As shown in Figures 3 and 14, the spring receiving portion 51c is provided with a guide engaging portion 51d that is notched radially inward and penetrates the spring receiving portion 51c in the front-rear direction. A total of two guide engaging portions 51d are provided at 180° intervals around the circumference of the second spring receiving portion 51c. Each guide engaging portion 51d engages with a corresponding guide 50e of the rotating gear 50. By engaging each guide engaging portion 51d with each guide 50e, the receiving cam 51 rotates integrally with the rotating gear 50 around the screw shaft axis K (see Figure 12). Furthermore, by engaging each guide engaging portion 51d with each guide 50e, the receiving cam 51 is movable in the front-rear direction relative to the rotating gear 50.

[0056] 12 to 14, when the receiving cam 51 is located at the forward position P1, the coil spring 52 is at approximately its natural length. When the receiving cam 51 is located at the forward position P1, a space S that allows the receiving cam 51 to move rearward is formed between the front surface of the cylindrical wall 50b and the rear surface of the second spring receiving portion 51c. The front-rear length of the guide 50e and the guide engaging portion 51d is set to a length that prevents the guide 50e and the guide engaging portion 51d from disengaging when the receiving cam 51 is located at the forward position P1.

[0057] As shown in FIGS. 3 and 14, the receiving cam 51 has multiple cam engagement portions 51e that protrude forward from the front surface 51f of the cylindrical portion 51a. Each cam engagement portion 51e is rectangular. A total of six cam engagement portions 51e are provided at 60° intervals around the circumference of the cylindrical portion 51a. The front-to-rear length D1 of the cam engagement portions 51e is equal to or less than the distance D2 over which the receiving cam 51 can move from a forward position P1 to a rearward retracted position P2 relative to the rotary gear 50. In other words, the distance D2 is equal to or greater than the front-to-rear length D1 of the cam engagement portions 51e. Note that the drawings show a forward position P1 that clearly shows the engagement between the guide 50e and the guide engagement portions 51d, but the actual forward position P1 can be set as far forward as possible, up to a position just before the guide 50e and the guide engagement portions 51d disengage.

[0058] As shown in Figures 9, 10 and 14, a concave jaw engagement portion (recess) 4b that engages with one of the multiple cam engagement portions 51e of the receiving cam 51 is provided on the rear surface of the jaw 4. By engaging each cam engagement portion 51e with the jaw engagement portion 4b of each jaw 4, the multiple jaws 4 rotate integrally with the receiving cam 51 around the screw shaft axis K. At both circumferential ends of each jaw engagement portion 4b, a convex portion 4d that convex rearward relative to the jaw engagement portion 4b is formed. The front-to-rear distance between the jaw engagement portion 4b and the convex portion 4d is approximately the same length as the front-to-rear length D1 of the cam engagement portion 51e.

[0059] As shown in Figures 9 and 10, a ring receiving groove 4a having an arc-shaped cross section is provided on the radial outer periphery of the rear portion of each 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 elastically expandable rings 4c inserted into the ring receiving grooves 4a. 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 radial movement of the ring 4c 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.

[0060] As shown in FIGS. 7 and 8, a magnet 28d is attached to the top of the roller shaft 28a. A screw shaft position sensor 29 that detects the longitudinal position of the screw shaft 27 is provided on the inner peripheral surface of the upper portion of the outer case 17. The screw shaft position sensor 29 is a sensor that detects magnetic fields, known as a Hall IC. The screw shaft position sensor 29 includes a rear end position sensor 29a and a front end position sensor 29b. The rear end position sensor 29a is located directly above the magnet 28d when the screw shaft 27 is located at the rear end position. The rear end position sensor 29a detects the rear end position of the screw shaft 27 when it overlaps with the magnet 28d in the longitudinal direction and sends a signal to the controller 9 (see FIG. 1). The front end position sensor 29b is located directly above the magnet 28d when the screw shaft 27 is located at the front end position. The front end position sensor 29b detects the front end position of the screw shaft 27 when it overlaps with the magnet 28d in the longitudinal direction and sends a signal to the controller 9.

[0061] The drive of the feed screw mechanism 25 and the jaw rotation mechanism 30 will be described with reference to Figures 7 to 13. First, the motor shaft 20a of the electric motor 20 rotates. The rotational drive of the motor shaft 20a is reduced by the planetary reduction mechanism 22 and transmitted to the gear shaft 23. When the gear shaft 23 rotates, the idle gear 24 meshed with the drive-side gear 23a rotates. The female screw member 26 meshed with the idle gear 24 via the driven-side gear 26a rotates around the screw shaft axis K. When the female screw member 26 rotates, the screw shaft 27, which is prevented from rotating by the screw shaft guide 28, moves back and forth. When the screw shaft 27 moves forward, the wedge 3 attached to the front end of the screw shaft 27 presses the multiple jaws 4 and the ring 4c to move them radially outward to an open position. When the screw shaft 27 moves backward, the pressing force of the wedge 3 is released, so the ring 4c contracts and the multiple jaws 4 return to their radially inward closed position.

[0062] The electric motor 20 is switched between forward and reverse rotation by the controller 9. The screw shaft 27 moves forward when the electric motor 20 rotates forward, and moves backward when the electric motor 20 rotates reverse. The controller 9 switches between forward and reverse rotation of the electric motor 20 based on a signal sent from the rear end position sensor 29a and a signal sent from the front end position sensor 29b.

[0063] As the screw shaft 27 advances, the push plate 34 attached to the roller shaft 28a also advances. The push plate 34 presses the ball retainer 35 forward against the biasing force of the compression spring 39. When the ball retainer 35 advances, the balls 38 engage with the ball grooves 33b, and the guide shaft 41 prevents the ball retainer 35 from rotating, causing the shaft 31 to rotate in the direction of the first rotation R1. At this time, the one-way clutch 42 does not transmit the rotational power of the shaft 31 to the drive-side gear 43. The rotating gear 50 does not rotate because no rotational power is transmitted from the drive-side gear 43. Therefore, the receiving cam 51 and the multiple jaws 4 connected to the rotating gear 50 do not rotate. Thus, the multiple jaws 4 do not rotate around the screw shaft axis K, but are pushed by the wedges 3 and open radially outward.

[0064] When the screw shaft 27 moves forward, the receiving cam 51 receives neither a circumferential rotational force nor a forward / backward movement force from the rotary gear 50 or the screw shaft 27. Therefore, the receiving cam 51 is held at the forward position P1 where the coil spring 52 is at approximately its natural length. No compression energy is stored in the coil spring 52 at approximately its natural length.

[0065] When the screw shaft 27 retracts, the push plate 34 attached to the roller shaft 28a also retracts. When the pressing force of the push plate 34 is released, the ball retainer 35 is biased by the compression spring 39 and moves rearward. When the ball retainer 35 retracts, the balls 38 engage with the ball grooves 33b, and the guide shaft 41 prevents the ball retainer 35 from rotating, causing the shaft 31 to rotate in the second rotation direction R2. At this time, the one-way clutch 42 transmits the rotational power of the front shaft 32 to the drive-side gear 43. The rotational power transmitted from the drive-side gear 43 to the rotating gear 50 causes the rotating gear 50 to rotate counterclockwise as viewed from the front. The receiving cam 51 and the multiple jaws 4 also rotate integrally with the rotating gear 50. Thus, the multiple jaws 4 close radially inward while rotating counterclockwise around the screw shaft axis K as viewed from the front.

[0066] When the screw shaft 27 moves backward, the receiving cam 51 receives a force from the rotary gear 50 that rotates it in the circumferential direction, but does not receive a force from the rotary gear 50 or the screw shaft 27 that moves it back and forth. Therefore, the receiving cam 51 is held at the forward position P1 where the coil spring 52 is at approximately its natural length. No compression energy is stored in the coil spring 52 at approximately its natural length.

[0067] As shown in Figures 1 and 14, the tube expanding tool 1 can removably mount multiple types of jaws 4, each with a different radial thickness. When a cap 2 holding multiple jaws 4 is removed from the main housing 11, the jaw engagement portions 4b of each jaw 4 disengage from the cam engagement portions 51e of the receiving cam 51. When a cap 2 holding a different type of jaw 4 is attached to the main housing 11, the jaw engagement portions 4b of each jaw 4 engage with the cam engagement portions 51e of the receiving cam 51. At this time, the jaw engagement portions 4b and the cam engagement portions 51e may not engage properly. For example, the protrusions 4d at both circumferential ends of the jaw engagement portion 4b abut against the cam engagement portions 51e in the front-to-rear direction. In this case, each jaw 4 is positioned forward of its normal position by approximately the front-to-rear length D1. As a result, the cap 2 cannot be fully attached to the main housing 11, and in this state, rotational drive from the receiving cam 51 to each jaw 4 is not transmitted properly.

[0068] In the jaw rotation mechanism 30 of the present disclosure, the receiving cam 51 is biased toward the forward position P1 by the coil spring 52. Furthermore, the receiving cam 51 can move in the front-rear direction from the forward position P1 to the retracted position P2 by a distance D2 that is equal to or greater than the front-rear length D1. Therefore, even if the protrusion 4d and the cam engagement portion 51e come into contact with each other in the front-rear direction and interfere with each other, the cam engagement portion 51e can be moved rearward by the distance D2 to release the interference between the protrusion 4d and the cam engagement portion 51e. Therefore, the jaw engagement portion 4b and the cam engagement portion 51e can be re-engaged in the correct state.

[0069] As described above, the pipe expanding tool 1 for expanding the diameter of the end of a synthetic resin fluid pipe has a threaded shaft 27 extending in the front-to-rear direction within the main housing 11, as shown in Figures 7 and 9. The pipe expanding tool 1 has an internally threaded member 26 that is threadedly engaged with the threaded shaft 27 and rotates around the axis of the threaded shaft 27, thereby moving the threaded shaft 27 back and forth. The pipe expanding tool 1 has multiple jaws 4 that open radially outward relative to one another when pressed by a wedge 3 provided at the front of the threaded shaft 27. The pipe expanding tool 1 has a cap 2 that supports the multiple jaws 4 so that they can be opened and closed radially and is removably attached to the main housing 11. The pipe expanding tool 1 has a receiving cam 51 that is movable in the front-to-rear direction and engages with the rear surfaces of the multiple jaws 4 so that it can rotate together with the multiple jaws 4 around the axis of the threaded shaft 27. The pipe expanding tool 1 has a coil spring (biasing member) 52 that biases the receiving cam 51 forward.

[0070] Therefore, when attaching the cap 2 having the multiple jaws 4 to the main body housing 11, the receiving cam 51 can move rearward. This prevents interference between the receiving cam 51 and the rear surfaces of the multiple jaws 4 in the front-to-rear direction. This allows the cap 2 to be easily attached to the main body housing 11 all the way to the rearmost position without stopping before the rearmost position. After the cap 2 has been attached to the rearmost position, the receiving cam 51 can be rotated around the screw shaft 27 relative to the multiple jaws 4, thereby properly engaging the forward-biased receiving cam 51 with the rear surfaces of the multiple jaws 4. This allows rotational power to be transmitted from the receiving cam 51 to the multiple jaws 4.

[0071] 7 and 9, the pipe expanding tool 1 has a rotary gear 50 that engages with a receiving cam 51 to rotate the receiving cam 51 about the axis of the screw shaft, thereby rotating the multiple jaws 4 about their axes. Therefore, when the receiving cam 51 and the rear surfaces of the multiple jaws 4 are engaged in the correct state, the receiving cam 51 is urged forward, allowing the rotational power of the rotary gear 50 to be efficiently transmitted to the multiple jaws 4 via the receiving cam 51. When the receiving cam 51 and the rear surfaces of the multiple jaws 4 are not engaged in the correct state, the engagement between the receiving cam 51 and the rear surfaces of the multiple jaws 4 can be restored to the correct state by moving the receiving cam 51 backward against the urging force.

[0072] As shown in Figures 7 and 9, the rotating gear 50 has a cylindrical wall 50b through which the screw shaft 27 and the wedge 3 are inserted. The rotating gear 50 has a spring receiving portion 50d extending radially inward from the cylindrical wall 50b. The receiving cam 51 is cylindrical, through which the screw shaft 27 and the wedge 3 are inserted, and is disposed coaxially with the rotating gear 50. The biasing member 52 is a coil spring disposed between the rotating gear and the receiving cam. The coil spring 52 is disposed on the inner periphery of the rotating gear 50, and its rear portion abuts against the spring receiving portion 50d. Therefore, the coil spring 52 can be compactly housed radially inside the cylindrical wall 50b of the rotating gear 50. This allows the outer peripheral regions of the rotating gear 50 and the receiving cam 51 to be compact. This allows the pipe expanding tool 1 to be provided in a compact form, improving the workability of, for example, expanding the end of a PEX pipe installed in a narrow space. Furthermore, the receiving cam 51 is biased forward with a substantially uniform force at any point in the circumferential direction, which prevents the receiving cam 51 from tilting relative to the screw shaft 27. This allows the receiving cam 51 to move smoothly back and forth.

[0073] 7 and 9, the main housing 11 has a first inner peripheral surface (bearing) 12b that slidably supports the outer peripheral surface of the cylindrical wall 50b of the rotating gear 50. Therefore, the rotating gear 50 can be rotated precisely around the axis of the screw shaft 27 while preventing the main housing 11 from becoming too large. This allows the diameters of the ends of PEX pipes installed in various locations to be expanded, and the diameters of the ends of the PEX pipes to be expanded into a uniform cylindrical shape.

[0074] As shown in FIGS. 3 and 14 , the rotating gear 50 is provided with a guide 50e that is convex or concave in the front-to-rear direction. The receiving cam 51 is provided with a guide engagement portion 51d that engages with the guide 50e so that it can move in the front-to-rear direction. The guide 50e and the guide engagement portion 51d allow the receiving cam 51 to move back and forth relative to the rotating gear 50, and the rotating gear 50 rotates the receiving cam 51 around the axis of the screw shaft 27. This reduces loss of rotational power transmitted from the rotating gear 50 to the receiving cam 51 and prevents the receiving cam 51 from moving up and down or left and right. This reduces unnecessary energy loss when rotating the multiple jaws 4 around the axis of the screw shaft 27. Furthermore, even when the coil spring 52 is in its natural length and not biasing the receiving cam 51, the rotating gear 50 and the receiving cam 51 can rotate together. This reduces fatigue damage to the coil spring 52.

[0075] 7 and 9, the coil spring 52 is provided between the rotary gear 50 and the receiving cam 51. The coil spring 52, the rotary gear 50, and the receiving cam 51 rotate integrally around the axis of the screw shaft 27. Therefore, when the rotary gear 50 and the receiving cam 51 are rotated around the axis of the screw shaft 27, it is possible to prevent compression energy or expansion energy from accumulating in the coil spring 52. This makes it possible to prevent excess energy loss in the coil spring 52. Furthermore, by reducing the number of times the coil spring 52 is compressed or expanded, fatigue damage to the coil spring 52 can be prevented.

[0076] As shown in FIG. 14, a cam engagement portion 51e having a convex shape extending in the front-rear direction is provided on the front surface 51f of the receiving cam 51. A jaw engagement portion 4b having a concave shape extending in the front-rear direction and engaging with the cam engagement portion 51e is provided on each rear surface of the multiple jaws 4. The receiving cam 51 can move rearward against the coil spring 52 by at least the front-rear length of the cam engagement portion 51e. Therefore, even when the front surface 51f of the receiving cam 51 and the rear surface of each jaw 4 are in maximum interference with each other, i.e., when the most protruding portion of the cam engagement portion 51e abuts against the most protruding portion of the convex portion 4d in the front-rear direction, the cam engagement portion 51e and the jaw engagement portion 4b can be returned to their normal engagement state by moving the receiving cam 51 rearward. This allows the cap 2 (see FIG. 7) to be attached to its rearmost position.

[0077] 7 and 9, the rotary gear 50 has a spring bearing portion (stopper) 50d that abuts against the rear end of the wedge 3 to prevent the wedge 3 from moving abnormally rearward. Therefore, providing the stopper 50d on the rotary gear 50 ensures the strength of the stopper 50d. This makes it possible to prevent a high load from being applied to other members that engage with the screw shaft 27, such as the feed screw mechanism 25 that moves the screw shaft 27 back and forth.

[0078] As shown in Figures 7 and 9, the rotating gear 50 has a cylindrical wall 50b through which the wedge 3 is inserted. A stopper 50d extends radially inward from the cylindrical wall 50b. The coil spring 52 is disposed on the inner circumferential side of the rotating gear 50. The rear portion of the coil spring 52 abuts against the spring receiving portion 50d. Therefore, when the rear portion of the coil spring 52 abuts against the spring receiving portion 50d, the coil spring 52 generates a biasing force that biases the receiving cam 51 forward. The spring receiving portion 50d serves both as a support portion for the coil spring 52 and as a stopper that restricts the retraction of the wedge 3, allowing the rotating gear 50 to be compact. Furthermore, by disposing the coil spring 52 on the inner circumferential side of the rotating gear 50, the coil spring 52 can be accommodated compactly. This allows the main housing 11 to be compact.

[0079] 7 and 9, balls 27b are interposed in the threaded portion between the screw shaft 27 and the female screw member 26. Therefore, the balls 27b interposed in the threaded portion improve the efficiency of power transmission from the female screw member 26 to the screw shaft 27. As a result, the rotational drive of the female screw member 26 can be efficiently converted into back and forth movement of the screw shaft 27.

[0080] Various modifications can be made to the tube expanding tool 1 of this embodiment described above. The tube expanding tool 1 has been exemplified as having six jaws 4. Instead, the tube expanding tool 1 may have, for example, five or fewer jaws 4 or seven or more jaws 4.

[0081] The jaw rotation mechanism 30 shown in this example rotates the multiple jaws 4 counterclockwise as viewed from the front. Alternatively, the multiple jaws 4 may be configured to rotate clockwise as viewed from the front. In this case, the rotation direction of the front shaft 32, in which the one-way clutch 42 transmits power to the drive-side gear 43, is counterclockwise as viewed from the front (the direction of the first rotation R1 shown in FIG. 5).

[0082] The feed screw mechanism 25 is exemplified as a ball screw mechanism in which balls 27b are interposed between the male screw 27a of the screw shaft 27 and the female screw 26b of the female screw member 26. Alternatively, the feed screw mechanism may be one in which the male screw 27a and the female screw 26b are directly threaded together and no balls are interposed.

[0083] The cylindrical wall 50b of the rotary gear 50 is shown as an example, through which both the screw shaft 27 and the wedge 3 can be inserted. Alternatively, the cylindrical wall 50b may be configured so that only one of the screw shaft 27 and the wedge 3, for example, only the screw shaft 27, can be inserted therethrough. The cylindrical portion 51a of the receiving cam 51 is shown as an example, through which both the screw shaft 27 and the wedge 3 can be inserted therethrough. Alternatively, the cylindrical portion 51a may be configured so that only one of the screw shaft 27 and the wedge 3, for example, only the wedge 3, can be inserted therethrough.

[0084] In the illustrated configuration, the rotary gear 50 is provided with a convex guide 50e, and the receiving cam 51 is provided with a concave guide engagement portion 51d. The concave and convex portions of the guide 50e and the guide engagement portion 51d may be reversed. The concave and convex portions of the cam engagement portion 51e and the jaw engagement portion 4b may be reversed.

[0085] The coil spring 52 has been exemplified as an urging member that urges the receiving cam 51 forward. However, a cylindrical rubber member or the like may be used instead. The coil spring 52 has been exemplified as being provided on the inner peripheral side of the cylindrical wall 50b of the rotating gear 50. However, the coil spring 52 may be provided on the outer peripheral side of the cylindrical wall 50b of the rotating gear 50. [Explanation of symbols]

[0086] 1…Pipe diameter expansion tool 2...Cap, 2a...Jaw support groove, 2b...Female thread 3...Wedge, 3a...Rear end 4... jaw, 4a... ring receiving groove, 4b... jaw engagement portion (recess), 4c... ring 4d...Convex part 5. Grip 6...switch lever, 6a...switch body 7...bulging portion, 7a...battery mounting portion 8...Battery 9...Controller 10...Tool body 11...Main body housing 12...Front mechanism housing, 12a...Male thread, 12b...First inner peripheral surface (bearing) 12c...Second inner peripheral surface, 12d...Radially extending surface, 12e...Flange 13...first central mechanism housing, 13a...inner peripheral surface, 13b...downward extension portion, 13c...recess 13d...through hole, 13e...shaft support portion, 13f...boss portion 14... second central mechanism housing, 14a... inner peripheral surface, 14b... downward extension portion, 14c... recessed portion 14d...through hole, 14e...guide shaft support portion, 14f...spring receiving portion 14g...shaft support part, 14h...boss part 15...rear mechanism housing, 15a...front surface, 15b...boss portion 16...Volts 17...Outer case 20...electric motor, 20a...motor shaft, 20b...stator, 20c...rotor 20d... rotation speed detection sensor, 20e, 20f... bearings 21...Fan 22...Planetary reduction mechanism 23... gear shaft, 23a... driving gear, 23b, 23c... bearings 24... idle gear, 24a... shaft member, 24b... radial bearing 25...Feed screw mechanism (ball screw mechanism) 26... female screw member, 26a... driven gear, 26b... female screw, 26c, 26d... bearings 26e...Thrust bearing 27...Screw shaft, 27a...Male thread, 27b...Ball 28...screw shaft guide, 28a...roller shaft, 28b...roller, 28c...rail 28d...Magnet 29...screw shaft position sensor, 29a...rear end position sensor, 29b...front end position sensor 30...Jaw rotation mechanism 31...Shaft 32...front shaft, 32a...female thread, 32b...width across flats 33... rear shaft, 33a... male thread, 33b... ball groove, 33c... width across flats 34...push plate, 34a...through hole 35...ball retainer, 35a...sleeve mounting portion, 35b...ball holding hole 35c... shaft insertion hole, 35d... lateral extension portion, 35e... through hole 36...Sleeve 37...Nut 38...Ball 39...Compression spring 41...Guide shaft 42...One-way clutch 43...Drive gear 50...rotating gear, 50a...driven gear, 50b...cylindrical wall, 50c...through hole 50d...Spring receiving part (stopper), 50e...Guide 51... receiving cam, 51a... cylindrical portion, 51b... insertion hole, 51c... second spring receiving portion 51d... guide engagement portion, 51e... cam engagement portion, 51f... front surface 52... Coil spring (biasing member) J: Motor axis K...screw shaft axis R1...First rotation R2: Second rotation S...gap D1...Front and back length D2…Movement distance P1…Front position P2…Evacuation position

Claims

1. A pipe diameter expanding tool for expanding the diameter of an end of a fluid pipe, a screw shaft extending in the front-rear direction within the main body housing; 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 plurality of jaws that are pushed by wedges provided at the front of the screw shaft and open radially outward relative to one another; a cap that supports the plurality of jaws so as to be openable and closable in the radial direction and is removably attached to the main body housing; a receiving cam that is movable in the front-rear direction and engages with rear surfaces of the plurality of jaws so as to be rotatable together with the plurality of jaws around the axis of the screw shaft; A tube expanding tool having a biasing member that biases the receiving cam forward.

2. The tube expanding tool according to claim 1, a tube expanding tool having a rotary gear that engages with the receiving cam to rotate the receiving cam about the axis of the screw shaft, thereby rotating the plurality of jaws about the axis;

3. The tube expanding tool according to claim 2, the rotary gear has a cylindrical wall into which the screw shaft and / or the wedge is inserted, and a spring bearing portion extending radially inward from the cylindrical wall, the receiving cam has a cylindrical shape through which the screw shaft and / or the wedge is inserted and which is disposed coaxially with the rotary gear, The urging member is a coil spring provided between the rotating gear and the receiving cam, and is arranged on the inner side of the rotating gear, with the rear portion of the urging member abutting against the spring receiving portion.

4. The tube expanding tool according to claim 3, The main body housing has a bearing that slidably supports the outer peripheral surface of the cylindrical wall of the rotary gear.

5. A tube expanding tool according to any one of claims 2 to 4, The rotary gear is provided with a convex or concave guide in the front-rear direction, The receiving cam is provided with a guide engaging portion that engages with the guide so as to be movable in the front-rear direction, The guide and the guide engagement portion allow the receiving cam to move back and forth relative to the rotating gear, and the rotating gear rotates the receiving cam around the axis of the screw shaft.

6. A tube expanding tool according to any one of claims 2 to 4, the biasing member is provided between the rotary gear and the receiving cam, The urging member, the rotary gear, and the receiving cam rotate integrally around the axis of the screw shaft in this pipe expanding tool.

7. The tube expanding tool according to any one of claims 1 to 4, A cam engaging portion having a convex or concave shape in the front-rear direction is provided on the front surface of the receiving cam, a jaw engaging portion that is concave or convex in the front-rear direction and engages with the cam engaging portion is provided on each of the rear surfaces of the plurality of jaws, The receiving cam is movable rearward against the biasing member by at least the front-to-rear length of the cam engaging portion.

8. A tube expanding tool according to any one of claims 2 to 4, The rotary gear has a stopper that abuts against the rear end of the wedge to prevent the wedge from moving abnormally rearward.

9. 9. The tube expanding tool according to claim 8, the rotary gear has a cylindrical wall having a cylindrical shape through which the wedge is inserted, The stopper extends radially inward from the cylindrical wall, the biasing member is disposed on the inner peripheral side of the rotary gear, A tube expanding tool in which the rear portion of the biasing member abuts against the stopper.

10. The tube expanding tool according to any one of claims 1 to 4, A pipe expanding tool in which a ball is interposed in the threaded portion between the screw shaft and the female thread member.

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