Thin wall tube with integral outer helical profile for use with endoscopes

Abstract

A polymer device includes: an elongated hollow tube having an outer surface; and a spiral fin wrapped around the outer surface of the hollow tube; wherein the hollow tube and the spiral fin are formed from a single integral piece by a molding process. The polymer device may also include a longitudinal protrusion protruding from the outer surface of the hollow tube, the longitudinal protrusion having a greater thickness than other portions of the hollow tube, and the longitudinal protrusion extending at least a portion of the longitudinal length of the hollow tube.

Description

Technical Field

[0001] The present disclosure relates generally to thin wall tubing and, more particularly, to thin wall coiled tubing for use with endoscopes and / or endoscope systems. Background Art

[0002] Typically, an insertion device, such as an insertion portion of an endoscope, is inserted, for example, into a lumen. One known such endoscope that is inserted into a lumen is a self-propelled insertion device.

[0003] In this rotary self-propelled insertion device, a rotating cylinder called a spiral tube is provided, on which spiral fins are formed on a thin-walled tube. The spiral tube is rotatably arranged on the outer circumferential surface of the insertion part of the endoscope. When the spiral tube rotates, the spiral fins contact the inner wall of the inner cavity, thereby generating a propulsion force. By this propulsion force, the insertion part is propelled in the insertion direction or the removal direction.

[0004] If the thin wall tube and the spiral fins are formed from a single integral component, the spiral tube presents a very difficult molded part to fill completely during the injection molding process. This is due to the high resistance to molten material flow in the thin wall tube portion of the spiral tube due to its very thin walls, which are typically about 0.018 inches thick. The definition of "thin wall" depends on many factors that prevent the resin from flowing to the end of the injection molded tube, such as material flow characteristics, resin pressure, gate, part geometry, and flow length. Injection molding of thin wall tubes usually results in incompletely formed ends of the thin wall tube because the molten material injected into the mold cavity has too much flow resistance due to the thin walls and cannot flow completely to the ends of the thin wall tube.

[0005] Due to these problems, conventional spiral tubes are formed from thin-walled tubes with spiral fins attached to the outer circumference of the tube as a secondary operation, such as by applying an ultraviolet (UV) cured acrylic adhesive, which requires precise dispensing and positioning, and curing by a calibrated light. Such spiral tubes include many additional forming steps and associated increases in manufacturing and quality control costs. Summary of the invention

[0006] Therefore, a polymer device is provided. The polymer device includes: an elongated hollow tube having an outer surface; and a spiral fin wrapped around the outer surface of the hollow tube; wherein the hollow tube and the spiral fin are formed from a single integral piece by a molding process.

[0007] The polymeric device may further include a longitudinal protrusion protruding from an outer surface of the hollow tube, the longitudinal protrusion having a greater thickness than other portions of the hollow tube and extending at least a portion of the longitudinal length of the hollow tube.

[0008] The longitudinal length of the longitudinal protrusion may extend from a portion of the spiral fin closest to the end of the hollow tube to the end of the hollow tube.

[0009] The polymer device may further include an end ring formed at an end of the hollow tube, the end ring having a thickness protruding from an outer surface of the hollow tube, a longitudinal length of the longitudinal protrusion extending from a portion of the spiral fin closest to the end of the hollow tube to the end ring.

[0010] The longitudinal protrusion may extend at least a portion of the longitudinal length of the hollow tube at a single circumferential location.

[0011] A polymer tubular member is also provided, comprising: an elongated hollow tube having an outer surface; a spiral fin of a spiral fin wound around the outer surface of the hollow tube; and a longitudinal protrusion protruding from the outer surface of the hollow tube, the longitudinal protrusion having a greater thickness than other parts of the hollow tube, and the longitudinal protrusion extending at least a portion of the longitudinal length of the hollow tube; wherein the hollow tube, the spiral fin and the longitudinal protrusion are formed from a single integral piece by a molding process.

[0012] The longitudinal length of the longitudinal protrusion may extend from a portion of the spiral fin closest to an end of the hollow tube to the end of the hollow tube.

[0013] The polymer tubular member may further include an end ring formed at an end of the hollow tube, the end ring having a thickness protruding from an outer surface of the hollow tube, the longitudinal protrusion having a longitudinal length extending from a portion of the spiral fin closest to the end of the hollow tube to the end ring.

[0014] The longitudinal protrusion may extend at least a portion of the longitudinal length of the hollow tube at a single circumferential location. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] These and other features, aspects and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters refer to like parts throughout the drawings, and in which:

[0016] Figure 1 An endoscope system is shown having a helical tube rotatably disposed on an insertion portion of the endoscope.

[0017] Figure 2 Shown is a schematic diagram of a 3D-printed ... Figure 2 The end of the spiral tube.

[0018] Figure 3 Shown along Figure 2 The line 3-3 in Figure 3 Cross-sectional view of a spiral tube.

[0019] Figure 4Shown is a representation for molding Figure 1 A perspective view of an embodiment of an injection mold for a spiral tube.

[0020] Figure 5 Shown according to Figure 4 A partial cross-sectional view of a molded spiral tube produced by an injection mold.

[0021] Figure 6 Shows Figure 4 Front view of one half of the injection mold.

[0022] Figure 7 Shown along Figure 6 A cross-sectional view taken along line 7-7 in FIG.

[0023] Figure 8 Shows Figure 4 View of the injection resin flow in the injection mold.

[0024] Fig. 9 Shows Figure 6 Alternative gate configurations for molds. DETAILED DESCRIPTION

[0025] While the disclosed embodiments are particularly applicable to thin walled coiled tubing for use with endoscopes and are described below with respect thereto, the apparatus and methods disclosed herein are not limited thereto and are applicable to other types of thin walled tubing with or without protrusions extending therefrom.

[0026] Reference now Figure 1 , which shows an endoscope system 200 having a spiral tube 204 rotatably disposed on an insertion portion 206 of an endoscope 202. The spiral tube 204 is formed into a cylindrical shape (generally referred to as a "polymer tube") using an elastic material such as rubber, resin, etc., and is rotatably attached to the insertion portion 206 about its longitudinal axis. The spiral tube 204 includes a spiral fin 208 disposed on an outer circumferential surface of the spiral tube 210 so that the spiral fin 208 extends along the longitudinal length of the spiral tube 210. The spiral tube 204 can be configured to be detachable from the insertion portion 206.

[0027] The solenoid 204 is connected to a motor provided as an actuator. The motor is connected to a controller 212 via a signal line for a motor current signal, which passes through an endoscope control body 214 and a universal cable 216 connecting the endoscope 202 and the controller 212.

[0028] When the spiral tube 204 rotates in contact with a wall (such as the inner wall of the lumen), a propulsion force is generated to propel the insertion portion 206. For example, in the small intestine or large intestine, the spiral fins 208 that rotate together with the spiral tube 204 crawl along the folds on the inner wall of the small intestine or large intestine, so that the propulsion force acts on the insertion portion 206. By this propulsion force, the insertion portion 206 is propelled. The self-propulsion of the insertion portion 206 facilitates the task of inserting and removing the insertion portion 206 by the user.

[0029] Next go to Figure 2 , which shows one end of a spiral tube 204 having a thin-walled tube 210 and a spiral fin 208 integrally formed as a single unitary piece by injection molding. The other end of the spiral tube 204 may have a Figure 2 The end shown is of the same construction, so for the sake of simplicity, this other end is not shown in Figure 2 The injection molding process includes a series of runners and gates that provide molten material to a cavity in the form of a spiral tube 204. Such gates typically provide a flow of molten material to multiple locations at the outermost circumferential position or face of the spiral fin 208. In turn, the spiral fin 208 typically serves as a gate to provide molten material to the thin-walled tube 210 portion of the spiral tube 204. However, in conventional spiral tubes, as described above with reference to Figure 1 Discussion, some portions of the thin-walled tube may not be completely filled by the injected molten material, especially at the ends of the thin-walled tube where there are no or very few spiral fin portions, or at some portions of the thin-walled tube between spiral fin protrusions.

[0030] Reference now Figure 2 and 3, the end portion 220 of the spiral tube 204 includes an internal flow channel 222 in the form of a longitudinal protrusion having an increased thickness in the radial direction of the thin-walled tube 210. Such an internal flow channel 222 is integrally formed with the thin-walled tube 210 and has a thickness and a circumferential width sufficient to increase the flow rate of the injected molten material so that the molten material completely and completely fills the end of the thin-walled tube 210. The thickness and width of the internal flow channel 222 can vary according to a number of factors, including material flow characteristics, gates, part geometry, flow length, and injection pressure. The thickness and / or width of the internal flow channel 222 is a compromise between allowing resin to flow to the end of the thin-walled tube 210 during injection molding and avoiding adversely increasing the stiffness of the thin-walled tube 210. The sides of the internal flow channel 222 can be angled or curved to form a smooth transition from the outer circumferential surface of the thin-walled tube 210 to the upper surface of the internal flow channel 222. Although shown as having a constant thickness along its longitudinal length, the internal flow passage 222 may alternatively have a varying thickness along its length, such as tapering from a greater thickness closer to the spiral fin 208 as compared to a thickness closer to the ends of the thin-walled tube 210 .

[0031] When the internal flow channel 222 is disposed at the end(s) 220 of the spiral tube 204, the longitudinal length of the internal flow channel 222 may be from the nearest spiral fin portion to a further point on the end 226 of the thin-walled tube 210 to provide flow of molten material from the nearest fin to the end 226. Since the spiral fin 208 may not be disposed at the very end 226 of the thin-walled tube 210, or may taper to a smaller diameter at the very end 226 of the thin-walled tube 210, the internal flow channel 222 may be formed at a circumferential location of the thin-walled tube 210 where no fins or very little portion of the fins are disposed to serve as a gate for transferring molten material to the end 226 of the thin-walled tube 210. In addition, the internal flow channel 222 may protrude radially outward from the outer outer circumferential surface of the thin-walled tube 210. The internal flow channel may alternatively be disposed on the inner diameter of the thin-walled tube 210, for example if the surface is blended to conform to the rest of the thin-walled tube structure.

[0032] As described above, the internal flow passage 222 may terminate at the endmost end 226 of the thin-walled tube, or alternatively, as Figure 2 As shown, the internal flow channel 222 may terminate at an end ring 224 having an increased thickness, which may be the same thickness as the internal flow channel 222. When the molten material is injected into the corresponding mold cavity of the spiral tube 204, the end ring 224 communicates with the internal flow channel 222.

[0033] Although the internal flow passage 222 is shown as being located at the end(s) 226 of the thin-walled tube 210, the internal flow passage may terminate just before the end, or may be located anywhere along the longitudinal length of the thin-walled tube 210, such as between one or more spiral fins 208. In addition, although the internal flow passage 222 is described and illustrated as being disposed at a single circumferential location, more than one internal flow passage 222 may be disposed in the circumferential direction to provide symmetry in the circumferential direction, such as at intervals of 60 degrees, 90 degrees, 120 degrees, or 180 degrees.

[0034] Although the internal flow channel 222 is described as a "flow channel", it is only a flow channel when molding the spiral tube 204. Therefore, the term "flow channel" discussed herein is also used to describe the thickened longitudinal protrusion of the thin-walled tube, which acts as a flow channel during the molding process to divert the molten injection material during the injection molding process to flow through the flow channel, thereby completely filling a specific area, such as the end of the thin-walled tube, with molten material.

[0035] Furthermore, although the spiral tube 204 is described herein, it will be understood by those skilled in the art that the mold for manufacturing the spiral tube 204 will have a mold cavity corresponding to the shape of the spiral tube 204, including an internal flow channel 222 in the form of a thickened longitudinal protrusion. It will also be understood by those skilled in the art that the mold cavity of the spiral tube 204 will include a series of runners and gates to provide molten material from outside the mold to the mold cavity, such as to one or more spiral fins, as such runners and gates are known in the art.

[0036] Will refer to Figure 4-8 An injection mold according to a first embodiment is described. Figure 4 is a schematic perspective view showing an example of the injection mold according to the first embodiment. Figure 5 20 is a schematic partial cross-sectional view of a spiral tube 204 molded product produced by the injection mold according to the first embodiment. Figure 6 is a schematic front view of an injection mold according to a first embodiment. Figure 7 is along Figure 6 Sectional view taken along the midline 7-7. Figure 8 yes Figure 6 204, showing the resin flow during the molding process of the spiral tube 204 molded product. As mentioned above, the shape of the molded thin-walled product produced by the injection mold is not particularly limited. The shape of the molded product can be, for example, box-shaped, cylindrical, rod-shaped, plate-shaped, frame-shaped, mesh-shaped, etc., wherein the corresponding mold cavity will have a corresponding shape.

[0037] The mold configuration of the injection mold may be appropriately selected according to the shape of the molded product produced by the injection mold. For example, the mold configuration of the injection mold may have or may not have a sliding core.

[0038] In the following, a method for producing Figure 4 The thin-walled molded product (spiral tube 204) shown (see Figure 5 ) is an example of an injection mold 1.

[0039] like Figure 4 As shown, the injection mold 1 includes a first slide core 1A, a second slide core 1B, and a core 1C. Although not specifically shown, the injection mold 1 also includes typical components such as a fixed die plate, a cavity mold, and a movable die plate.

[0040] The injection mold 1 is used to manufacture the spiral tube 204 by injection molding. As described above, the spiral tube 204 includes the tubular portion 210 and the spiral fins 208 protruding from the tubular portion 210. Except for the internal flow passage 222 and the end ring 224, the wall thickness of the tubular portion 210 is constant in the axial direction.

[0041] like Figure 5 As shown, the molded spiral tube 204 product has a tubular portion 210 and a spiral fin 208. The tubular portion 210 is a thin-walled tube extending along the central axis O. The tubular portion 210 has an inner diameter D, a wall thickness t1, a wall thickness t2 at the internal flow channel and / or the end ring, and a length L. For example, L can be 50 mm or greater. D can be 5 mm to 50 mm. t1 can be 0.1 mm to 2 mm, and t2 can be an increased thickness greater than t1, which provides resin flow to the end of the thin-walled tube 210 under the above conditions while avoiding harmful reduction in flexibility. The spiral fin 208 protrudes in a radial direction from the outer circumferential surface 54d of the tubular portion 210 in a spiral or spiral manner over the entire circumference of the outer circumferential surface 54d. The spacing between the multi-channel spiral fins 208 is not particularly limited.

[0042] Figure 5 The spiral tube 204 shown also includes an internal flow passage 222 and an end ring 224 located at each end of the thin-walled tube 210. Figure 5 In the illustrated configuration, the internal flow passage 222 extends from the last spiral fin 208 at each end to an end ring 224 .

[0043] The material of the spiral tube 204 is not particularly limited as long as it is a resin material that can be injection molded. The material of the spiral tube 204 may be a hard resin material or a soft resin material such as an elastomer.

[0044] Next, the injection molding die 1 for forming the spiral tube 204 will be described.

[0045] In the following, reference will be made to Figure 4The XYZ orthogonal coordinate system shown is described. The Z axis is an axis extending in the moving direction of the movable side template, etc. The X axis is an axis orthogonal to the Z axis. In a plane including the X axis but orthogonal to the Z axis, the Y axis is an axis orthogonal to the X axis. The directions along the X axis, Y axis and Z axis are respectively called the X direction, the Y direction and the Z direction.

[0046] The first sliding core 1A and the second sliding core 1B are arranged facing each other in the Y direction. When the injection molding mold 1 is opened and closed, the first sliding core 1A and the second sliding core 1B can be slidably moved in at least the Y direction. The core 1C is arranged along an axis parallel to the Z axis. The core 1C is fixed to the movable side template and can be moved in the Z direction together with the movable side template. The first sliding core 1A and the second sliding core 1B form the shape of the outer periphery of the spiral tube 204.

[0047] The shapes of the first slide core 1A and the second slide core 1B are similar. Therefore, the description will continue to focus on the shape of the first slide core 1A.

[0048] The outer shape of the first slide core 1A is a substantially rectangular parallelepiped elongated in the Z direction. The first slide core 1A has a first end face 1a parallel to the XY plane at one end in the Z direction. The first end face 1a faces a fixed-side mold plate (not shown) of the injection mold 1 when the mold is closed.

[0049] The first slide core 1A has a second end surface 1b parallel to the XY plane at the opposite end to the first end surface 1a in the Z direction. The second end surface 1b abuts against a movable side plate (not shown) of the injection mold 1 when the mold is closed.

[0050] The first sliding core 1A has a parting surface 1c at the surface facing the second sliding core 1B. The parting surface 1c is a plane parallel to the XZ plane. There is a recessed portion in each parting surface 1c, and when the injection mold 1 is closed, the recessed portion forms the outer shape of the spiral tube 204. A molding space for molding the spiral tube 204 is formed between the recessed portion and the core 1C. The recessed portion (i.e., the molding surface) constituting the part of the molding space forms the outer shape of the spiral tube 204 by transferring the surface shape to the injection resin filled in the molding space.

[0051] Each parting surface 1c has a recessed portion for forming a resin flow path for filling the molding resin into the molding space. The recessed portion forming the molding space is composed of the tubular portion molding surface 4a, the spiral fin molding surface 4b, the inner flow channel molding surface 4c and the end ring molding surface 4d. The recessed portion forming the resin flow path includes a first resin flow path portion P1 and a second resin flow path portion P2.

[0052] The tubular portion molding surface 4a forms a half shape of the outer circumferential surface 54d of the tubular portion 210. The tubular portion molding surface 4a is a semicircular groove extending along the center axis OA in the Z direction at the center. The semicircular groove is defined as a groove having a semicircular cross-sectional shape orthogonal to the extension direction. In the semicircular groove, the radius of the semicircle in the cross section is called the groove radius. The semicircular groove has an extension surface corresponding to the spiral fin 208, the internal flow channel 222, and the end ring 224.

[0053] The central axis OA extends parallel to the Z axis at the center of the parting surface 1c. The groove radius of the tubular portion molding surface 4a is D / 2. The tubular portion molding surface 4a passes between the first end surface 1a and the second end surface 1b in the Z direction. The length of the tubular portion molding surface 4a is equal to the total length L of the spiral tube 204.

[0054] like Figure 6 As shown, the spiral fin molding surface 4b is a recessed portion in the parting surface 1c and the tubular portion molding surface 4a. The spiral fin molding surface 4b forms the spiral fin 208 of the spiral tube 204. The shape of the spiral fin molding surface 4b matches the outer shape of the spiral fin 208. Similarly, the internal flow channel molding surface 4c and the end ring molding surface 4d form the internal flow channel 222 and the end ring 224 of the spiral tube 204. The internal flow channel molding surface 4c and the end ring molding surface 4d are formed at two positions corresponding to each end of the spiral tube 204. The shapes of the internal flow channel molding surface 4c and the end ring molding surface 4d match the outer shapes of the corresponding internal flow channel 222 and the end ring 224.

[0055] like Figure 4 As shown, the core 1C is a cylindrical member having a cylindrical outer circumferential surface 1d. The core 1C forms the shape of the inner circumferential surface 54e of the spiral tube 204. The outer diameter of the outer circumferential surface 1d of the core 1C is D, which matches the inner diameter of the spiral tube 204. The length of the core 1C is L, which corresponds to the length of the spiral tube 204. The end faces 1e and 1f formed at both ends along the axial direction of the core 1C are planes orthogonal to the central axis OC of the outer circumferential surface 1d.

[0056] Similar to the first slide core 1A, the tubular portion molding surface 4a and the spiral fin molding surface 4b are also formed in the parting surface 1c of the second slide core 1B centered on the central axis OB. However, Figure 6The coordinate system in shows the orientation of the first sliding core 1A. The end ring molding surface 4d is also formed in the parting surface 1c of the second sliding core 1B. Because the internal flow channel 222 can be arranged asymmetrically on the thin-walled tube 210, the entire internal flow channel molding surface 4c can be formed only on one of the first sliding core 1A or the second sliding core 1B, or a portion of the internal flow channel molding surface 4c can be formed on each of the first sliding core 1B and the second sliding core 1B.

[0057] When the corresponding parting surfaces 1c of the first slide core 1A and the second slide core 1B abut when the injection mold 1 is closed, the center axes OA and OB coincide with each other. At this time, the tubular portion molding surface 4a, the spiral fin 4b molding surface 4b, the inner flow channel molding surface 4c and the end ring molding surface 4d facing each other in the Y direction form the shape of the outer circumferential surface of the spiral tube 204.

[0058] As indicated by the two-dot chain line, the core 1C is inserted into the center of the inner space surrounded by the tubular portion molding surface 4a in the Z direction. The end faces 1e and 1f of the core 1C are aligned in the same plane as the first and second end faces 1a and 1b of the first and second slide cores 1A and 1B, respectively.

[0059] As a result, a molding space S surrounded by the outer circumferential surface 1d of the core 1C, the tubular portion molding surface 4a, the spiral fin molding surface 4b, the inner flow ring molding surface 4c, and the end ring molding surface 4d is formed.

[0060] The first resin flow path portion P1 and the second resin flow path portion P2 have symmetrical shapes with respect to a symmetry plane passing through the central axis OA and parallel to the YZ plane. Hereinafter, the shape of the first resin flow path portion P1 will be described with emphasis.

[0061] The first resin flow path portion P1 includes an inlet runner groove 2A, a first runner groove 2B, a second runner groove 2C, a third runner groove 2D, and a gate groove 3A. The inlet runner groove 2A is a semicircular groove extending between the injection port 2a and the opening 2b. The groove radius of the inlet runner groove 2A is constant. The injection port 2a is a semicircular opening for injecting the injection resin M into the inlet runner groove 2A. The injection port 2a leads to the first end face 1a.

[0062] The opening 2b is formed at a position facing the central portion of the spiral fin molding surface 4b in the X direction (ie, the Z direction). The path of the inlet runner groove 2A is not particularly limited. Figure 6In the embodiment, the inlet runner groove 2A extends from the injection port 2a in the Z direction, bends away from the central axis OA in the X direction, bends toward the reference plane m in the Z direction, and forms a path that bends toward the opening 2b in the X direction at a position facing the opening 2b. The inner diameter of the inlet runner groove 2A is set to an appropriate size that allows the molten injection resin M to flow well.

[0063] The first runner groove 2B is a semicircular groove along a path that is concavely curved toward the center axis OA. Both ends of the first runner groove 2B extend in the X direction to the position of the gate groove 3A (described later) facing both sides of the reference plane m and farthest from the reference plane m. The first runner groove 2B is symmetrical with respect to the reference plane m. The curved shape of the first runner groove 2B is set to change the X-direction length of the second runner groove 2C (described later) according to the position in the Z direction.

[0064] like Figure 7 As shown, the groove radius of the first runner groove 2B is a constant value rB. Figure 7 As shown, the second runner groove 2C is a groove connected to the side of the first runner groove 2B facing the third runner groove 2D, which will be described later. The depth of the second runner groove 2C from the parting surface 1c is tC, where tC <rB。

[0065] like Figure 6 As shown, the second runner groove 2C is connected to the first runner groove 2B over substantially the entire length of the first runner groove 2B. The width of the second runner groove 2C in the X direction varies in the Z direction according to the amount of curvature of the first runner groove 2B. In addition, as viewed in the Y direction, the shape of the second runner groove 2C is symmetrical with respect to the reference plane m.

[0066] The third runner groove 2D is a semicircular groove extending linearly in the X direction. The third runner groove 2D is located at a position facing the entire first runner groove 2B in the X direction, and the second runner groove 2C is interposed therebetween. The second runner groove 2C is connected to the third runner groove 2D. The length of the third runner groove 2D in the Z direction is the same as the molding range of the first runner groove 2B. The center of the third runner groove 2D in the Z direction is located on the reference plane m. Figure 7 As shown, the groove radius of the third runner groove 2D is a constant value rD, where rD>tC.

[0067] The gate groove 3A is a recessed portion for enabling communication between different portions of the spiral fin molding surface 4b and the third runner groove 2D facing the spiral fin molding surface 4b in the X direction. The gate groove 3A is a semicircular groove having an axis extending in the X direction as a center. For example, the gate groove 3A has a shape obtained by dividing the shape of a pinpoint gate (pingate) in half from the center. Figure 7 As shown, the gate opening 3a leading to the molding space S optimizes the speed of the injection resin M entering the molding space S formed at the distal end of the gate groove 3A. In the gate groove 3A, the radius of the opening 3c communicating with the third runner groove 2D is smaller than rD. The gate groove 3A divides the injection resin M flowing in the third runner groove 2D toward the spiral fin molding surface 4b in the Z direction.

[0068] like Figure 6 As shown, the first resin flow path portion P1 and the second resin flow path portion P2 similar to those in the first slide core 1A are also formed on the parting surface 1c of the second slide core 1B. When the injection molding die 1 is closed, when the respective parting surfaces 1c of the first slide core 1A and the second slide core 1B come into contact with each other, the respective first resin flow path portion P1 and the respective second resin flow path portion P2 facing each other in the Y direction form resin flow paths F1 and F2 having circular and rectangular flow path cross sections.

[0069] The resin flow paths F1 and F2 each include an inlet runner R 2A (i.e. upstream runner), first runner R 2B (i.e., downstream runner, first circular tube flow path, first runner portion), second runner R 2C (i.e. downstream runner, second runner portion, plate-shaped flow path), third runner R 2D (ie, the downstream runner, the second circular tube flow path, the third runner portion) and the gate GA.

[0070] Entrance runner R 2A The inlet runner R is a flow path formed by combining the inlet runner grooves 2A facing each other in the Y direction. 2A An upstream runner having an injection port 2a is configured, into which the injection resin M is injected. The first runner R 2B , Second runner R 2C and the third runner R 2D With the entrance gate R 2A It communicates with the gate GA and constitutes a runner that distributes the injection resin M injected into the injection port 2a to the downstream of the gate GA.

[0071] First runner R 2B is through the first runner grooves 2 facing each other in the Y directionB The flow path formed by combination. The first runner R 2B is a first circular tube flow path having a first inner diameter of 2×rB. The opening 2b opens at the center (i.e., the central part) of the first runner R 2B The first runner R 2B faces the corresponding gate GA, with the second runner R 2C and the third runner R 2D therebetween and extending along the position of the gate GA.

[0072] The second runner R 2C is a flow path formed by combining second runners R 2C facing each other in the Y direction. The second runner R 2C is a plate-shaped flow path having a flow path width of 2×tC in the thickness direction. The second runner R 2C forms a slit SL1 (see Figure 7 ) with a width of 2×tC, which is the same as the flow path width in the general overall extension direction of the first runner R 2B on the X-direction side of the first runner R 2B Since the flow path width is smaller than the first inner diameter, the flow path cross-section of the second runner R 2C has a higher resistance than the flow path cross-section of the first runner R 2B .

[0073] As Figure 6 shown, the length of the second runner R 2C in the direction towards the gate GA (i.e., the X direction) decreases as the distance from the reference plane m in the extension direction of the first runner R 2B increases; for example, the length of the second runner R 2C at the gate GA (referred to as the first gate) at the center in the Z direction is L0. The length of the second runner R 2C at the point corresponding to the gate GA provided beside the center gate GA is L1, where L1 < L0. The length of the second runner R 2C at each gate GA set to be farther from the reference plane m than each gate GA is L2, where L2 < L1. The lengths L0, L1, and L2 are set such that the arrival times of the injection resin M from the opening 2b to the first gate, the gate GA, and the second gate are the same. Each length can be determined, for example, by flow simulation of the injection resin M.

[0074] The third runner R 2D is a flow path formed by combining third runners R 2D facing each other in the Y direction. The third runner R 2Dis a second circular tube flow path with a second inner diameter of 2×rD. Because the second inner diameter is larger than the second runner R 2C The flow path width, so the third runner R 2D The flow path cross section is larger than the second runner R 2C The flow path cross section has lower resistance. The second runner R 2C A slit SL2 with a width of 2×tC is formed (see Figure 7 ), the width is the same as that of the third runner R 2D The third runner R on the X direction side 2D The flow path width in the substantially entire extension direction of the gate GA is the same. The gate GA is a flow path formed by combining the gate grooves 3A facing each other in the Y direction.

[0075] With this structure, in the second runner R 2C In the first runner R 2B The shortest distance of the flow path to each gate GA is different depending on the shortest distance between the opening 2b and each gate GA. 2C In the first runner R 2B The shortest distance in the flow path to the first gate closest to the opening 2b is L0. On the other hand, the first runner R 2B The flow path of the second runner R 2C In the flow path at the point corresponding to the second gate, from the first runner R 2B The shortest distance toward the gate becomes shorter as the shortest distance from the opening 2b to each gate becomes longer, like L1 and L2.

[0076] Now refer to Figure 8 A manufacturing process of the spiral tube 204 using the injection mold 1 is described. Figure 8 is a view of a flow of an injected resin in an injection mold according to the first embodiment.

[0077] When manufacturing the spiral tube 204, the injection mold 1 is attached to an injection molding machine (not shown). When the injection mold 1 is closed, a molding space S and resin flow paths F1, F2 communicating with the molding space S through the spiral fin molding surface 4c are formed inside the assembly consisting of the first slide core 1A, the second slide core 1B and the core 1C. Each injection port 2a in the first end surface 1a for the resin flow paths F1, F2 communicates with an injection port (not shown) in a cavity mold plate (not shown).

[0078] The injection resin M injected in a molten state from the injection molding machine is injected into the resin flow paths F1, F2 through the injection port and each injection port 2a. The injection amount of the injection resin M is predetermined according to the total volume of the molding space S and the resin flow paths F1 and F2. Since the resin flow paths F1 and F2 are similar flow paths except that they are in different positions, only an example of the resin flow path F1 will be described below.

[0079] like Figure 8 As shown, the injection resin M injected into the injection port 2a of the resin flow path F1 flows along the inlet runner R 2A The injection resin M flows toward the opening 2b along the path in the injection path. 2A When the injection resin M enters the first runner R from the opening 2b, the injection resin M flows in the X direction extending from the distal end of the first runner R. 2B When the injection resin M flows to the first runner R 2B Due to the first runner R 2B The opening 2b extends in the Z direction, so a T-shaped branch flow path that branches in two directions (from the X direction to the Z direction) is formed near the opening 2b. Therefore, the flow of the injected resin M is branched to the first runner R toward the first end surface 1a. 2B and a first runner R toward the second end surface 1b 2B In the first runner R 2B The side is opened, and a part of the injected resin M flows into the second runner R through the slit SL1. 2C .

[0080] However, since the opening width of the slit SL1 (ie, the width in the Y direction) is smaller than the first runner R 2B The first inner diameter, so the second runner R 2C The flow path resistance is greater than the first runner R 2B As a result, the resin MB, which is the injection resin M other than the resin MC, is injected into the first runner R. 2B The amount of resin MB is significantly greater than that of resin MC.

[0081] The flow velocity of the resin MC is proportionally lower than the flow velocity of the resin MB according to the cross-sectional dimensions of the flow path in the flow direction. 2D Before flowing into the gate GA, the resin MC fills the first runner R 2B . In the first runner R 2B When the filling of the injection resin M in the first runner R is completed (hereinafter referred to as the first filling completion time), a nearly uniform injection pressure is applied to the first runner R 2BAll the injected resin M in the second runner R is completely squeezed out from the slit SL1 to the second runner R 2C middle.

[0082] Until the first filling is completed, the resin MC gradually flows into the second runner R 2C Because the first runner R is filled with resin MB 2B The time spent corresponds to the first runner R 2B length, so the resin MC flows into the second runner R 2C The timing of the resin MC is delayed as the distance from the reference plane m in the Z direction increases. The pressure applied to the resin MC decreases as the distance from the reference plane m in the Z direction increases. As a result, the resin MC flows into the second runner R 2C The amount of the resin MC decreases as the resin MC moves away from the reference plane m in the Z direction. Similarly, the flow speed of the resin MC decreases as the resin MC moves away from the reference plane m in the Z direction.

[0083] Therefore, when the first runner R 2B When it is a straight line, in the second runner R 2C The resin MC traveling in the flow direction spreads out in a fan shape, and the flow length of the resin MC at the reference plane m is the longest. 2B Towards the third runner R 2D The front edge of the resin MC is curved concavely so that the front edge of the resin MC is aligned with the first runner R 2B Therefore, by appropriately setting the second runner R 2C The size of the flow path cross section resistance and the first runner R 2B to reduce the curvature of the second runner R 2C Difference in fill time in the Z direction.

[0084] When the second runner R 2C The outlet is along the third runner R 2D When the first runner R is linear, 2B The curvature of the second runner R 2C The flow path length in the first runner R 2B In this way, as the resin MC flows toward the third runner R 2D As the resin MC moves forward, its leading edge becomes flat in the X direction. As a result, the resin MC moves along the second runner R 2C Each position in the Z direction is filled at the same time. 2C The time at which the filling is completed is hereinafter referred to as the second filling completion time.

[0085] Flows into the second runner R 2CThe resin MC is turbulent before the first filling completion time. If the second runner R is shortened to further reduce the size of the injection mold 1, 2C The length of the resin MC in the X direction, the leading edge position of the resin MC in the X direction can be changed to a certain extent according to the position in the Z direction. 2D , reducing the time deviation of the injected resin M arriving at each gate GA due to the disturbance of the leading edge of the resin MC.

[0086] Passing through the second runner R in the X direction 2C The resin MC flows into the third runner R through the slit SL2 2D . The third runner R 2D The second inner diameter of is larger than the opening width of the slit SL2 (i.e., the width in the Y direction). 2D The resin MD flows into the third runner R 2D When the resin MD is dispersed, the flow rate of the resin MD is reduced. Therefore, when the resin MD fills the third runner R to a certain extent, 2D Thereafter, resin MD flows from the nearby gate into the molding space S. The resin flowing into the internal flow channel molding space 4c allows the resin to flow toward the end of the tubular portion molding surface 4a to completely fill the molding space S corresponding to the end of the tubular portion molding surface 4a and further fill the end ring molding surface 4d (if provided).

[0087] As a result, no void is formed at the end of the resulting spiral tube 204, and even if the resin MD is 2D The amount in the longitudinal direction of the resin MC varies due to the change in the leading edge of the resin MC, and the time when the resin MD reaches each gate is equal. As described above, in this embodiment, even if the positions of the gates GA in the Z direction are different from each other, the injected resin M reaches each gate GA at the same time.

[0088] Fill the third runner R with the injected resin M 2D After that, the injection resin M fills the molding space S through the gate GA because a substantially uniform injection pressure is applied to all the injection resin M in the downstream runner. The injection resin M filled into the molding space S is cooled by conducting heat to the first slide core 1A, the second slide core 1B, and the core 1C. Figure 4As shown, when the injection resin M is left for a period of time during which the temperature of the injection resin M becomes equal to or lower than the glass transition point, a molded body 50 is formed in which the injection resin M in the injection mold 1 is solidified. Thereafter, the injection mold 1 is opened. When the injection mold 1 is opened, the first slide core 1A and the second slide core 1B are separated from each other in the Y direction. This enables the molded body 50 to be demolded. The molded body 50 includes a spiral tube 204 and flow path resin portions Q1, Q2.

[0089] The flow path resin portion Q1 is formed by curing the injection resin M filled in the resin flow path F1. The flow path resin portion Q1 includes a runner resin portion 52 and a gate resin portion 53A. The runner resin portion 52 is a portion corresponding to the shapes of the upstream runner and the downstream runner. The gate resin portion 53A is a portion corresponding to the shapes of the gate GA, respectively. The flow path resin portion Q2 is formed by curing the injection resin M filled in the resin channel F2. Similar to the flow path resin portion Q1, the flow path resin portion Q2 includes a runner resin portion 52 and a gate resin portion 53A. The molded product 54 is manufactured by separating the flow path resin portions Q1 and Q2 from the molded body 50 through a secondary operation known in the art.

[0090] Reference now Fig. 9 , showing Figure 6 An alternative gate configuration to the gate configuration shown, where the same features are replaced with Figure 6 The same reference numerals are used to represent the same reference numerals as in the examples. Fig. 9 In the embodiment, the gate 3B for supplying resin from the runner groove 2D may alternatively have an output portion 3a on the side surfaces 4ba, 4bb of each spiral fin molding surface 4b. In this configuration, the internal flow channel molding surface 4c may extend from the side surface 4ba of the spiral fin molding surface 4b, which is opposite to the side surface 4bb where the gate 3B enters the spiral fin molding surface 4b. As described above, such internal flow channel molding surface 4c may extend to the corresponding end of the thin-walled tube molding surface 4a, or alternatively, to the end ring molding surface 4d (if provided). Although in Fig. 9 Only one spiral fin molding surface 4b is shown, but all of these channels may have similar gate configurations, or some of these channels (such as only the end channel) may have Fig. 9 The gate structure.

[0091] The internal flow channel 222 described above can be configured to provide the necessary resin flow to the end of a thin wall tube molded product while maintaining the desired flexibility requirements, which is particularly applicable to spiral tubes used on the insertion portion of an endoscope. Rather than thickening the wall of the entire tube 210 or thickening a large portion thereof, the internal flow channel 222 enables highly controlled and directed plastic to flow to the final fill area without adversely increasing the bending stiffness of the tube 210. In order to be used in endoscopic inspection procedures, the spiral tube 204 must maintain the required amount of flexibility.

[0092] Although what is considered to be the preferred embodiment has been shown and described, it should of course be understood that various modifications and changes in form or details can be easily made without departing from the spirit of the invention. Therefore, the present invention is not limited to the exact form described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.

Claims

1. A polymer device comprising: an elongated thin-walled hollow tube having an outer surface configured to be rotatably disposed on an insertion portion of an endoscope; as well as an internal flow passage in the form of a longitudinal protrusion that projects from an outer surface of the elongated thin-walled hollow tube; a spiral fin wound around the outer surface of an elongated, thin-walled hollow tube; The elongated thin-walled hollow tube, spiral fins and internal flow passage are formed from a single integral piece through a molding process.

2. The polymer device according to claim 1, wherein: The internal flow channel has a greater thickness than other portions of the elongated thin-walled hollow tube, and the internal flow channel extends at least a portion of the longitudinal length of the elongated thin-walled hollow tube.

3. The polymer device according to claim 2, wherein: The longitudinal length of the internal flow passage extends from a portion of the spiral fin closest to an end of the elongated thin-walled hollow tube to the end of the elongated thin-walled hollow tube.

4. The polymer device according to claim 2 further includes an end ring formed at the end of the slender thin-walled hollow tube, the end ring having a thickness protruding from the outer surface of the slender thin-walled hollow tube, and the longitudinal length of the internal flow channel extends from a portion of the spiral fin closest to the end of the slender thin-walled hollow tube to the end ring.

5. The polymer device according to claim 2, wherein: The internal flow passage extends at least a portion of the longitudinal length of the elongated thin-walled hollow tube at a single circumferential location.

6. A polymer tubular member comprising: an elongated thin-walled hollow tube having an outer surface configured to be rotatably disposed on an insertion portion of an endoscope; a spiral fin wound around the outer surface of an elongated, thin-walled hollow tube; as well as an internal flow channel in the form of a longitudinal protrusion protruding from an outer surface of the elongated thin-walled hollow tube, the internal flow channel having a greater thickness than other portions of the elongated thin-walled hollow tube and extending at least a portion of the longitudinal length of the elongated thin-walled hollow tube; The elongated thin-walled hollow tube, spiral fins and internal flow passage are formed from a single integral piece through a molding process.

7. The polymer tubular member of claim 6, wherein: The longitudinal length of the internal flow passage extends from a portion of the spiral fin closest to an end of the elongated thin-walled hollow tube to the end of the elongated thin-walled hollow tube.

8. The polymer tubular member according to claim 6 further includes an end ring formed at the end of the slender thin-walled hollow tube, the end ring having a thickness protruding from the outer surface of the slender thin-walled hollow tube, and the longitudinal length of the internal flow channel extends from a portion of the spiral fin closest to the end of the slender thin-walled hollow tube to the end ring.

9. The polymer tubular member of claim 6, wherein: The internal flow passage extends at least a portion of the longitudinal length of the elongated thin-walled hollow tube at a single circumferential location.

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