Bushing for corrugated tube and cable fixture with corrugated tube

Abstract

To provide a bushing for a corrugated tube which fixes and holds the corrugated tube to a connection member while fixing a cable by the connection member and imparting waterproofness.SOLUTION: The bushing includes a cylindrical portion side 10a having an inside diameter larger than an outside diameter of the corrugated tube and having an inside diameter portion into which the corrugated tube can be inserted, a cone-shaped portion side 10b provided at one end of the cylindrical portion and having a shape conforming to an inside shape of a cap of the connecting member, a plurality of spiral projection portion side 10f having a shape to be fitted into recesses provided in an outside diameter portion of the corrugated tube and having a plurality of projections spirally provided in accordance with a pitch of the recesses, and a claw portion side 10d provided on one end side of the cylindrical portion and projecting toward a center of the inside diameter of the cylindrical portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a corrugated bushing used to fasten a corrugated tube to a connecting member, and a cable fastener with a corrugated tube using the same. [Background technology]

[0002] Corrugated tubes are commonly used around cables such as wire harnesses to make them easier to handle and protect them from the environment. These corrugated tubes often have a bellows structure with alternating annular convex and concave sections along their length, but some have spiral structures. The annular convex sections have flat or mountain-shaped tops, and these irregularities give the corrugated tube flexibility. Various materials, including resin and metal, are used depending on the application. In the case of resin, durable plastic materials such as polypropylene (PP) and polyamide (PA) are often used.

[0003] A connecting member is used to secure a cable covered in a corrugated tube to the inlet of a device to prevent water and dust from entering the device. The connecting member is sometimes called a cable gland, a connecting joint, a connecting fitting, or a grommet, and some are also called by registered trademarks, such as SC-Lock (a registered trademark of Seiwa Electric Co., Ltd.).

[0004] The connecting components are used in machine tools, industrial machinery, industrial robots, vehicles, ships, various plants, office automation equipment, general electrical equipment, waterproof equipment, lighting equipment, various display devices, sensors, limit switches, solenoid valves, pressure switches, distribution boards, control panels, distribution boards, operation panels, and various cable wiring work in control centers.

[0005] Connecting members are used in a variety of devices, and for this reason, the inner diameter of the connecting member is specified in advance to match the outer diameter and number of cables. Furthermore, even if the inner diameter is the same, there is a certain range of outer diameters of cables that can be used. Various configurations have been disclosed for fixing cables and corrugated tubes using such connecting members.

[0006] For example, a grommet has been disclosed that has a cylindrical portion and a flange portion that is larger in diameter than the cylindrical portion and has an inner end portion located radially inward and connected to one end of the cylindrical portion, the inner end portion of the flange portion being formed to protrude radially outward beyond the outer surface of the cylindrical portion, and has an outer surface facing the cylindrical portion and an inner surface opposite the outer surface and facing the internal space of the flange portion, and a recess is formed at the connection portion between the one end of the cylindrical portion and the inner end portion of the flange portion that is recessed more toward the inner surface of the inner end than the outer surface of the inner end.It is said that by using such a shape, it is possible to improve the waterproofness of a wire harness used in a vehicle (see, for example, Patent Document 1).

[0007] Furthermore, in a connecting member for a corrugated tube comprising a housing with an opening and a hollow portion for inserting the end of the corrugated tube, a connecting flange, a through hole, and a connecting portion provided between the outer jacket of the end of the corrugated tube and the inner jacket of the hollow portion of the housing, the connecting portion comprising a sleeve having an elastic member and locking members facing radially inward and outward, a structure has been disclosed in which the sleeve is formed as an injection-molded member in which multiple members are joined together, and the sleeve includes a first cylindrical member that forms the main portion of the sleeve, a second cylindrical member that covers at least a portion of the outer jacket of the first cylindrical member, and a third cylindrical member that covers at least a portion of the inner jacket of the first cylindrical member (see, for example, Patent Document 2).

[0008] Furthermore, a waterproof quick coupling for a bellows tube, including a coupling body, a waterproof fastening unit, and a crimped part, has been disclosed, which is composed of a coupling body with a first joint portion and a second joint portion extending from both ends, a flexible waterproof tube, and a locking engagement ring, one end of the flexible waterproof tube having a recessed receiving portion for fitting the locking engagement ring, the inner surface of the flexible waterproof tube having an inclined surface that tightens toward one end of the coupling body, and the inner peripheral edge of the locking engagement ring having an array of elastic engagement pieces for tightening the bellows tube, and the peripheral edge of the locking engagement ring having a notch extending in the axial direction, and a waterproof fastening unit having an insertion opening for inserting the bellows tube and screwed to the second joint portion of the coupling body, the inner edge having a pressing surface formed near the insertion opening, and the pressing surface pressing against the locking engagement ring of the waterproof fastening unit and the corresponding end face of the crimped part (see, for example, Patent Document 3).

[0009] Furthermore, a cable gland has been disclosed which is a tubular member through which a cable can be inserted, and which has a flange and a cylindrical cable holding portion and an attachment portion provided on either side of the flange, with external threads formed on the outer surfaces of the cable holding portion and the attachment portion, a sleeve having an insertion hole for the cable to pass through and fitted into the cable holding portion, a cap having internal threads that engage with the external thread of the cable holding portion, and a lock nut having internal threads that engage with the external thread of the attachment portion, and which has a structure in which the attachment portion of the gland body is inserted into an attachment hole formed in the wall to which the cable gland is to be attached, and the gland body is attached to the wall by screwing the lock nut into the attachment portion, and with the sleeve fitted into the cable holding portion of the gland body, the cap is screwed onto the cable holding portion (see, for example, Patent Document 4).

[0010] Also disclosed is a bushing for a corrugated pipe that has an annular flange, a cylindrical insertion portion that is formed integrally with the flange and extends in the axial direction, claws that protrude radially outward and are provided on a part of the outer wall of the insertion portion, and means for displacing the claws radially inward when an external force is applied (see, for example, Patent Document 5). [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent Publication No. 2020-120443 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-510993 [Patent Document 3] Utility Model Registration No. 3122351 [Patent Document 4] Patent No. 6239696 [Patent Document 5] Japanese Patent Application Laid-Open No. 2007-51680 Summary of the Invention [Problem to be solved by the invention]

[0012] In the invention described in Patent Document 1, when the flange is attached to the panel, the tubular portion located on the outside of the panel fits around the outer periphery of the corrugated tube, and the annular lip on the inner periphery fits into a recess on the outer periphery of the corrugated tube. Furthermore, the corrugated tube is secured by tightening it from the outer periphery with a fastening member such as a cable tie or crimping ring, ensuring waterproofing. In this invention, the corrugated tube is secured to the grommet with a cable tie or the like, but if the fastening force of the cable tie is weak, the adhesion between the grommet and the corrugated tube may be insufficient, resulting in insufficient waterproofing. Furthermore, the inner diameter of the grommet's tubular portion and the outer diameter of the corrugated tube must be specified in advance.

[0013] The invention described in Patent Document 2 discloses a configuration consisting of a housing and a sleeve as a connecting member for fixing a corrugated tube and providing waterproofing. The sleeve is composed of a first cylindrical member forming the main portion, a second cylindrical member, and a third cylindrical member, the third cylindrical member being made of a soft elastomer and provided with a sealing lip. This allows the corrugated tube and housing to be fixed together and waterproofed. This invention also has the problem that, because the corrugated tube is fixed to the housing to provide waterproofing, the inner diameter of the end of the housing and the outer dimensions of the corrugated tube must be predetermined.

[0014] The device described in Patent Document 3 consists of a fitting body to which a fixed object is attached and a crimping part that tightens a bellows tube, with a waterproof fixing unit provided between the fitting body and the crimping part. This waterproof fixing unit consists of a soft rubber waterproof tube and a nylon locking ring, with a recessed receiving portion molded into the end of the soft waterproof tube that fits into the locking ring, and a sloped surface molded into the inner edge. This device also has the problem that the outer diameter of the bellows tube and the inner diameter of the waterproof unit are only allowed to have a tolerance sufficient to fit, so only tubes with predetermined dimensions can be used.

[0015] The invention described in Patent Document 4 tightens the cap by screwing it down, thereby reducing the diameter of the sleeve and sealing the gap between the cable and the sleeve, thereby achieving waterproofing and resistance to pulling out. However, this invention does not disclose or suggest a corrugated tube to protect the cable.

[0016] Furthermore, the invention of Patent Document 5 aims to protect the end of the corrugated tube from external damage or to provide electrical insulation, and is not intended to fix a cable to equipment using a connecting member to provide waterproofing, nor does it fix the corrugated tube to the connecting member.

[0017] For example, if the cable gland described in Patent Document 4 is used as a connecting member, tightening the cap presses and deforms the rubber sleeve housed inside, thereby applying a tightening force to the cable. This tightening force creates a tight seal between the cable and the rubber sleeve, ensuring waterproofing. Furthermore, this tightening force can also be used to clamp the cable. However, this cable gland does not have a function for fixing a corrugated tube, making it difficult to use a corrugated tube to protect the cable.

[0018] An object of the present invention is to provide a bushing for a corrugated tube, which can secure and hold a corrugated tube to a connecting member while securing the cable with the connecting member and providing waterproofing, and a fixing device for a cable with a corrugated tube to equipment. [Means for solving the problem]

[0019] In order to solve the above-mentioned conventional problems, the bushing for a corrugated tube of the present invention is used to secure a cylindrical corrugated tube that covers the outer periphery of a cable to a connecting member that secures the cable to equipment, and is characterized by including: a cylindrical portion whose inner diameter is larger than the outer diameter of the corrugated tube, so that the corrugated tube can be inserted into the inner diameter portion; a cone-shaped portion that is provided at one end of the cylindrical portion and has a shape that follows the shape of the inside of the cap of the connecting member; a plurality of helical protrusions that are shaped to fit into recesses that are provided on the outer diameter portion of the corrugated tube on the inner diameter portion of the cylindrical portion and have a plurality of protrusions arranged in a spiral pattern to match the pitch of the recesses; and a claw portion that protrudes from one end of the cylindrical portion toward the center of the inner diameter of the cylindrical portion.

[0020] With this configuration, after the connecting member is attached to the device, the corrugated tube can be inserted into the cylindrical portion of the bushing for corrugated tube (hereinafter referred to as the "bushing"), whereby the protrusions of the bushing and the recesses of the corrugated tube fit together and secure the tube in place. Because the protrusions are arranged spirally, the corrugated tube can be easily inserted or removed by simply rotating it while inserting or removing it from the cylindrical portion of the bushing. Once inserted, the protrusions fit into the recesses, allowing the corrugated tube to be fixed and held in place.

[0021] The number of protrusions can be set in various ways depending on the length of engagement with the outer diameter of the corrugated tube. The circumferential length of the protrusions may be set based on the number of helical protrusions. For example, when four helical protrusions are arranged circumferentially, if each helical protrusion occupies 1 / 4 of the inner diameter surface of the bushing, the helical protrusions will not overlap, making it easier to insert and remove the corrugated tube. In this case, the circumferential length of the protrusions may be calculated by dividing 1 / 4 of the inner diameter of the cylindrical portion by the number of protrusions to be arranged. The arrangement of the helical protrusions may be set based on the mold shape and injection molding conditions used to manufacture the bushing.

[0022] In the above configuration, it is preferable that the multiple helical protrusions are arranged at the same angle with respect to the cross section of the cylindrical portion. For example, when arranging four helical protrusions, if they are arranged at 90-degree angle changes with respect to the cross section of the cylindrical portion, the protrusions will be arranged symmetrically with respect to the cross section, making it easy to insert and remove the corrugated tube.

[0023] In the above configuration, the cylindrical portion may be made of a material having rubber elasticity, and the cone-shaped portion may be made of a resin material that is harder than the cylindrical portion, and the cone-shaped portion may be fixed to the cylindrical portion. With this configuration, the cylindrical portion through which the corrugated tube is inserted and removed has rubber elasticity, making it easy to insert and remove even a relatively hard corrugated tube. Examples of materials having rubber elasticity include natural rubber and synthetic rubber. The cylindrical shape with a spiral protrusion on the inner diameter portion can be manufactured by, for example, injection molding.

[0024] Synthetic rubbers include nitrile rubber (NBR), which has good oil resistance, silicone rubber, which has high heat resistance, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, ethylene propylene rubber (EPDM), etc. Furthermore, rubber elasticity and hardness can be controlled as needed by controlling the amount of carbon black added and the vulcanization conditions.

[0025] Furthermore, the cylindrical portion is not limited to being made solely of a material having rubber elasticity. For example, it may have a double structure in which a first material has rubber elasticity and a second material having a rubber elasticity modulus greater than that of the first material (i.e., harder than the first material) covers the first material. With such a structure, the first material mainly deforms during insertion and removal, allowing the corrugated tube to be inserted and removed, and when fixing and holding the corrugated tube, the second material presses the protrusions fitted into the recesses of the corrugated tube, allowing for more stable fixing and holding.

[0026] In the above configuration, the cylindrical portion may be made of a thermoplastic resin material and may have multiple slits formed therein parallel to the cylindrical axis. The slits are preferably formed in areas other than the corrugated tube insertion opening and the cone-shaped portion of the cylindrical portion, but may be formed only in the area where the spiral protrusion is formed. By providing slits, the resin material is more likely to deform in a radially expanding direction when the corrugated tube is inserted or removed. Therefore, when the corrugated tube is rotated and pushed in, the resin material deforms in a radially expanding manner, facilitating insertion. After the protrusions of the bushing are fitted into the recesses of the corrugated tube, the protrusions can be fixed and held in place by the resin material.

[0027] Both the cylindrical portion and the cone-shaped portion may be molded using the same resin material by injection molding or the like, or the cylindrical portion and the cone-shaped portion may be manufactured separately using different resin materials and then fixed together by thermocompression bonding, adhesive, or the like.

[0028] The resin material can be any thermoplastic resin that can be injection molded, such as polypropylene (PP), polyamide (PA6, PA66), polyphenylene sulfide (PPS), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), or fiber-reinforced resins made by adding glass fiber or carbon fiber to these resins. These resin materials can be used to manufacture the product using known manufacturing methods such as injection molding and extrusion molding.

[0029] a connecting member including: a corrugated tube for covering and protecting the outer periphery of the cable; a corrugated tube for covering and protecting the outer periphery of the cable; and a bushing as described above. The bushing is a tubular member through which the cable can be inserted, the main body having a flange and a cylindrical cable holding portion and a cylindrical mounting portion, the main body being provided on both sides of the flange and having a male thread formed on the outer periphery thereof; a sleeve having an insertion hole for passing the cable and fitted into the cable holding portion, the cap having a female thread that mates with the male thread of the cable holding portion; a gasket for sealing the mounting portion when inserted into a mounting hole formed in the device; and a lock nut having a female thread that mates with the male thread of the mounting portion; and a corrugated tube for covering and protecting the outer periphery of the cable. The main body is fixed to the device via the gasket by the lock nut, and the cone-shaped portion of the bushing is inserted into the cap. The cap is tightened to deform the sleeve, thereby tightly fixing the cable and the cone-shaped portion. The corrugated tube is inserted into the bushing, and the bushing is fixed by fitting a protrusion on the inner diameter of the bushing into a recess on the outer diameter of the corrugated tube. Specifically, the cable and the cone-shaped portion being tightly fixed to each other means the following: the sleeve and the cable are tightly fixed to each other, the cap and the cone-shaped portion, and the sleeve and the cone-shaped portion are tightly fixed to each other.

[0030] With this configuration, the gasket and lock nut seal the space between the inside and outside of the device, and tightening the cap deforms the sleeve to seal the outer periphery of the cable, preventing water from entering the device, and the corrugated tube can be fixed and held in place simply by inserting it into the bushing. This makes it easy to insert and remove the corrugated tube, while also ensuring a stable fixation and retention. [Effects of the Invention]

[0031] The present invention allows a cable to be fixed to equipment by inserting a corrugated tube into a bushing while using a connecting member with waterproofing functions, and is therefore highly effective in fields where cables protected by corrugated tubes are connected to equipment. [Brief explanation of the drawings]

[0032] [Figure 1] 1A and 1B are diagrams showing a bushing according to a first embodiment, in which (a) is a perspective view seen from a slightly oblique angle in the horizontal direction, (b) is a perspective view seen from an obliquely upward direction, and (c) is a diagram showing the inner diameter portion cut along the AA direction shown in (b) (i.e., the cylindrical axial direction of the bushing). [Figure 2] 1A and 1B are diagrams showing the attachment relationship between the connecting member, bushing, and device according to the first embodiment, where (a) is an exploded perspective view, and (b) is a photograph showing the state of attachment to the device as seen from the side. [Figure 3] 1A and 1B are diagrams showing the process of attaching a connecting member and a bushing according to the first embodiment, in which (a) shows the state in which the main body of the connecting member is fixed to the device with a lock nut, with the upper part being a cross-sectional view and the lower part being a side view, and (b) showing a photograph taken from an angle. [Figure 4] The figure shows the state in which the cone-shaped part of the bushing is inserted into the cap, the cable is inserted, and then the cap is screwed down to apply pressure to the sleeve, sealing the gap between the sleeve and the cable. (a) is a cross-sectional view of the upper part, (b) is a side view of the lower part, and (c) is a photograph taken from an angle. [Figure 5] This figure shows the state in which the corrugated tube is inserted and the recess of the corrugated tube is fitted into the protrusion of the bushing. (a) shows a cross-sectional view of the upper part, (b) shows a side view of the lower part, and (c) shows a photograph taken from an angle. [Figure 6] 10A and 10B are diagrams showing a bushing according to a second embodiment, in which (a) is a perspective view seen from a slightly oblique angle in the horizontal direction, (b) is a perspective view seen from an oblique angle from above, and (c) is a diagram showing the inner diameter portion cut along the cylindrical axial direction of the bushing. [Figure 7] FIG. 10 is an exploded perspective view showing the attachment relationship between a connecting member, a bushing, and a device according to a second embodiment. [Figure 8]This figure shows the state in which the cone-shaped portion of the bushing is inserted into the cap, the cable is inserted, the cap is then screwed down to apply pressure to the sleeve to seal the gap between the sleeve and the cable, and then the corrugated tube is inserted so that the recess of the corrugated tube is fitted into the protrusion of the bushing.The upper part is a cross-sectional view, and the lower part is a side view. DETAILED DESCRIPTION OF THE INVENTION

[0033] (First embodiment) A bushing according to a first embodiment of the present invention and a fixing device using the bushing will be described in detail below.

[0034] FIG. 1 shows a bushing according to a first embodiment, where (a) is a perspective view seen from a slightly oblique angle in the horizontal direction, (b) is a perspective view seen from diagonally above, and (c) is a view showing the inner diameter portion cut along the AA direction shown in (b) (i.e., the cylindrical axial direction of the bushing).

[0035] FIG. 2 is a diagram showing the attachment relationship between the connecting member, bushing, and device according to the first embodiment, where (a) is an exploded perspective view, and (b) is a photograph showing the state of attachment to the device as seen from the side.

[0036] Figure 3 shows the process of attaching the connecting member and bushing according to the first embodiment, where (a) shows the state in which the main body of the connecting member is fixed to the equipment with a lock nut, with the upper part being a cross-sectional view and the lower part being a side view, and (b) a photograph taken from an angle.

[0037] Figure 4 shows the state in which the cone-shaped part of the bushing is inserted into the cap, the cable is inserted, and then the cap is screwed down to apply pressure to the sleeve, sealing the gap between the sleeve and the cable. The upper part of (a) is a cross-sectional view, the lower part is a side view, and (b) is a photograph taken from an angle.

[0038] Figure 5 shows the state in which the corrugated tube has been inserted and the recess of the corrugated tube has been fitted into the protrusion of the bushing. The upper part of (a) is a cross-sectional view, the lower part is a side view, and (b) is a photograph taken from an angle. Hereinafter, a bushing according to a first embodiment of the present invention and a method for attaching a fastener using the bushing will be described with reference to these drawings.

[0039] The bushing 10 according to this embodiment is used to secure a cylindrical corrugated tube 50 that covers the outer periphery of a cable 40 to a connection member 20 that secures the cable 40 to a device 30. The bushing 10 includes a cylindrical portion 10a having an inner diameter dimension larger than the outer diameter dimension of the corrugated tube 50 and an inner diameter portion into which the corrugated tube 50 can be inserted, a cone-shaped portion 10b provided at one end of the cylindrical portion 10a and shaped to fit the inner shape of the cap 21 of the connection member 20, a plurality of helical protrusions 10f extending from the other end of the cylindrical portion 10a to a predetermined inner diameter portion, the plurality of helical protrusions 10f being shaped to fit into recesses 50a provided on the outer diameter portion of the corrugated tube 50 and having a pitch that matches the recesses 50a, and a claw portion 10d protruding from one end of the cylindrical portion 10a toward the center of the inner diameter of the cylindrical portion 10a. The cylindrical portion 10a is characterized in that it is elastically deformed in the radial direction by the pressing force when the corrugated tube 50 is inserted.

[0040] In this embodiment, five protrusions 10c of the helical protrusion portion 10f are provided in accordance with the pitch of the recesses 50a provided on the outer diameter portion of the corrugated tube 50. In addition, in this embodiment, four of the helical protrusion portions 10f are arranged at the same angle, i.e., shifted by 90 degrees, with respect to the cross section of the cylindrical portion 10a.

[0041] In this embodiment, four openings 10e are provided between the cylindrical portion 10a and the cone-shaped portion 10b. These openings 10e are provided to prevent abnormal deformation when the cone-shaped portion 10b is pressed by deformation of the sleeve 22 and for draining water. These openings 10e are provided as a countermeasure against the risk of water entering from the opposite side of the corrugated tube.

[0042] Furthermore, in this embodiment, the cylindrical portion 10a is made of a material having rubber elasticity. For example, the cylindrical portion 10a may be made of nitrile rubber. The inner diameter, wall thickness, circumferential length of the protrusions 10c, and protrusion height can be set to various dimensions to suit the connecting member and the corrugated tube. An attachment tool 100 for attaching the bushing 10 and the connecting member 20 to the device 30 and inserting the corrugated tube 50 into the bushing 10 will now be described.

[0043] The mounting device 100 includes the above-mentioned bushing 10, a main body 23 which is a tubular member through which the cable 40 can be inserted, the main body 23 having a flange 23a, a cylindrical cable holding portion 23b and a cylindrical mounting portion 23c which are provided on both sides of the flange 23a and have male threads formed on their outer surfaces, an elastic sleeve 22 which has an insertion hole through which the cable 40 passes and is fitted into the cable holding portion 23b, a cap 21 which is formed with female threads 21a which mesh with the male threads of the cable holding portion 23b, a gasket 24 which seals the mounting portion 23c when inserted into a mounting hole 30a formed in the device 30, and a lock nut 25 which is formed with female threads 25a which mesh with the male threads of the mounting portion 23c, and a corrugated tube 50 which covers and protects the outer periphery of the cable 40 (see Figures 2 and 5).

[0044] The main body 23 is fixed to the equipment 30 with a lock nut 25 via a gasket 24, the cone-shaped portion 10b of the bushing 10 is inserted into the cap 21, and the cap 21 is tightened to deform the sleeve 22, thereby tightly fixing the cable 40 and the cone-shaped portion 10b together, and the corrugated tube 50 is inserted into the bushing 10, and the protrusion 10c on the inner diameter of the bushing 10 is fitted into the recess 50a on the outer surface of the corrugated tube 50, thereby fixing the bushing 10 in place.

[0045] The main body 23, lock nut 25, and cap 21 may be made of metal such as brass, or may be made of resin such as polypropylene. The resin is not limited to polypropylene, but may be acrylonitrile butadiene styrene (ABS), polyamide, or a molded resin that has been mixed with reinforcing fibers to increase its strength.

[0046] Gasket 24 is used to seal mounting hole 30a of device 30 and provide waterproofing, so it is preferable to use silicone rubber, which is used in O-ring seals. Sleeve 22 deforms when cap 21 is screwed in, pressing against cable 40 from the periphery and providing a tight seal, providing waterproofing. To maintain waterproofing for a long period of time, the elastic force that tightly seals cable 40 must be maintained for a long period of time. To provide such properties, silicone rubber, like gasket 24, may be used, or nitrile rubber, butylene rubber, or the like may also be used.

[0047] Next, a description will be given of the assembly process of the fixing device 100, in which the connecting member 20 is attached to the device 30, the cable 40 and the bushing 10 are fixed, and then the corrugated tube 50 is inserted and fixed.

[0048] First, as shown in Figures 2 and 3, the gasket 24 is inserted into the mounting portion 23c of the main body 23, and then the main body 23 is inserted into the mounting hole 30a provided in the wall of the equipment 30 and fixed with a lock nut 25 by screwing.

[0049] Next, the bushing 10 is inserted into the cap 21 from the side where the internal thread 21a is formed, exposing the cylindrical portion 10a from the cap 21 while leaving the cone-shaped portion 10b on the inner surface of the cap 21. After that, the sleeve 22 is stored inside the cable holding portion 23b, and the cap 21 is lightly screwed onto the cable holding portion 23b. Next, the cable 40 is pulled out from the device 30 to the cylindrical portion 10a. After this state, the cap 21 is firmly screwed. By screwing, the sleeve 22 is pressed and expands in the direction pressing against the cable 40, filling the gap between the cable 40 and the sleeve 22. This ensures waterproofing and secures the cable 40. At this time, the cone-shaped portion 10b of the bushing 10 is also pressed by the sleeve 22, and the bushing 10 is secured to the connecting member 20 (see FIG. 4).

[0050] Next, as shown in Figure 5, the corrugated tube 50 is inserted into the cylindrical portion 10a of the bushing 10. As the corrugated tube 50 is inserted, the protrusions 10c of the bushing 10 repeatedly come into contact with the convex portions on the outer diameter of the corrugated tube 50 and fit into the concave portions, and when they come into contact with the convex portions, the cylindrical portion elastically deforms in the radial direction. Note that if the corrugated tube 50 is inserted while being rotated, the protrusions 10c are arranged in a spiral, so insertion can be carried out smoothly even if they come into contact with the convex portions.

[0051] After confirming that the tip of the corrugated tube 50 is inserted up to the claw portion 10d of the bushing 10, the bushing 10 is adjusted so that the protrusion 10c fits into the recess 50a of the corrugated tube 50. This allows the corrugated tube 50 to be fixed and held to the connecting member.

[0052] With the corrugated tube 50 fixed and held, a vibration test was conducted on the fixing device 100 and the equipment 30, but the corrugated tube 50 did not come off, confirming that the holding performance was sufficient for practical use.

[0053] The inner diameters of the connecting member and the bushing may be set to suit corrugated tubes of various diameters. However, the present invention is not limited to this. For example, the same connecting member may be used to securely hold corrugated tubes of smaller diameters. Specifically, a bushing may be manufactured and used in which the inner diameter (including the outer diameter) of the cylindrical portion is reduced to suit corrugated tubes of smaller outer diameters while the outer diameter of the cone-shaped portion remains the same. (Second embodiment) A bushing according to a second embodiment of the present invention and a fixing device using the bushing will now be described in detail.

[0054] FIG. 6 shows a bushing according to a second embodiment, where (a) is a perspective view seen from a slightly oblique angle in the horizontal direction, (b) is a perspective view seen from an oblique angle from above, and (c) is a view showing the inner diameter portion cut along the cylindrical axial direction of the bushing. FIG. 7 is an exploded perspective view showing the attachment relationship between the connecting member, the bushing, and the device according to the second embodiment.

[0055] Figure 8 shows the state in which the cone-shaped portion of the bushing is inserted into the cap, the cable is inserted, and then the cap is screwed down to apply pressure to the sleeve to seal the gap between the sleeve and the cable, and then the corrugated tube is inserted so that the recess of the corrugated tube fits into the protrusion of the bushing.The upper part is a cross-sectional view, and the lower part is a side view. Hereinafter, a bushing according to a second embodiment of the present invention and a method for attaching a fastener using the bushing will be described with reference to these drawings.

[0056] The bushing 60 of this embodiment is used to secure a cylindrical corrugated tube 50 that covers the outer periphery of the cable 40 to a connection member 20 that secures the cable 40 to a device 30. The bushing 60 includes a cylindrical portion 60a whose inner diameter is larger than the outer diameter of the corrugated tube 50 and has an inner diameter portion into which the corrugated tube 50 can be inserted, a cone-shaped portion 60b provided at one end of the cylindrical portion 60a and shaped to fit the inner shape of the cap of the connection member, a plurality of helical protrusions 60f that extend from the other end of the cylindrical portion 60a to a predetermined inner diameter portion and are shaped to fit into recesses 50a provided on the outer diameter portion of the corrugated tube 50, and that have a plurality of protrusions 60c spirally arranged to match the pitch of the recesses 50a, and a claw portion 60d that protrudes from one end of the cylindrical portion 60a toward the center of the inner diameter of the cylindrical portion 60a, and the cylindrical portion 60a is characterized in that it elastically deforms in the radial direction due to the pressing force of the corrugated tube 50 being inserted.

[0057] In this embodiment, the cylindrical portion 60a is made of a thermoplastic resin material, and has a plurality of slits 60e formed in the cylindrical portion 60a parallel to the cylindrical axis direction. Five protrusions 60c of the helical protrusion portion 60f are provided on the inner diameter portion of the cylindrical portion 60a between the slits 60e, matching the pitch of the recesses 50a provided on the outer diameter portion of the corrugated tube 50. Four helical protrusions 60f are provided, and are arranged at equal angles, i.e., every 90 degrees, based on the cross section of the cylindrical portion 60a.

[0058] In this embodiment, the cylindrical portion 60a is manufactured by injection molding using polyamide 6 (PA6), but is not limited to polyamide 6. It may also be manufactured by injection molding using polypropylene (PP), polystyrene, polyethylene terephthalate, polycarbonate, acrylonitrile butadiene styrene (ABS), etc. Furthermore, it may also be manufactured by injection molding using a mixture of these resins and reinforcing fibers such as glass fiber or carbon fiber. Furthermore, the cone-shaped portion 60b of the bushing 60 is preferably molded simultaneously with the cylindrical portion 60a, but may be manufactured separately and then bonded together by thermocompression or the like.

[0059] As described above, the bushing 60 of this embodiment is manufactured by injection molding using polyamide 6, but the manufacturing method is the same as commonly used injection molding, so a detailed description will be omitted. Furthermore, the outer diameter, inner diameter, length of the cylindrical portion, number of protrusions, and other dimensions of the bushing 60 can be set to various dimensions according to the shapes of the connecting member 20, cable 40, and corrugated tube 50 used. An attachment tool 110 for attaching the bushing 60 and the connecting member 20 to the device 30 and inserting the corrugated tube 50 into the bushing 60 will now be described.

[0060] The mounting device 110 includes the above-mentioned bushing 60, a main body 23 which is a tubular member through which the cable 40 can be inserted, the main body 23 having a flange 23a, a cylindrical cable holding portion 23b and a cylindrical mounting portion 23c which are provided on both sides of the flange 23a and have male threads formed on their outer surfaces, an elastic sleeve 22 which has an insertion hole through which the cable 40 passes and is fitted into the cable holding portion 23b, a cap 21 which is formed with female threads 21a that mesh with the male threads of the cable holding portion 23b, a gasket 24 which seals the mounting portion 23c when inserted into a mounting hole 30a formed in the device 30, and a lock nut 25 which is formed with female threads 25a that mesh with the male threads of the mounting portion 23c, and a corrugated tube 50 which covers and protects the outer periphery of the cable 40 (see Figure 7).

[0061] Then, the main body 23 is fixed to the device 30 with a lock nut 25 via a gasket 24, the cone-shaped portion 60b of the bushing 60 is inserted into the cap 21, and the cap 21 is tightened to deform the sleeve 22, thereby closely fixing the cable 40 and the cone-shaped portion 60b, and the corrugated tube 50 is inserted into the bushing 60, and the protrusion 60c on the inner diameter of the bushing 60 is fitted into the recess 50a on the outer diameter of the corrugated tube 50 to fix and hold it in place. This process is the same as in the first embodiment.

[0062] The main body 23, lock nut 25, and cap 21 may be made of metal such as brass, or may be made of resin such as polypropylene. The resin is not limited to polypropylene, but may be acrylonitrile butadiene styrene (ABS), polyamide, or a molded resin that has been mixed with reinforcing fibers to increase its strength.

[0063] Gasket 24 is used to seal mounting hole 30a of device 30 and provide waterproofing, so it is preferable to use silicone rubber, which is used in O-ring seals. Sleeve 22 deforms when cap 21 is screwed in, pressing against cable 40 from the periphery and providing a tight seal, providing waterproofing. To maintain waterproofing for a long period of time, the elastic force that tightly seals cable 40 must be maintained for a long period of time. To provide such properties, silicone rubber, like gasket 24, may be used, or nitrile rubber, butyl rubber, or the like may also be used.

[0064] 8 shows the state of the fixing device 110 with the corrugated tube 50 inserted, and the assembly process is the same as that of the first embodiment. However, when expanding the cylindrical portion 60a of the bushing 60 to insert the corrugated tube 50, it is necessary to apply a larger force than in the bushing 10 of the first embodiment.

[0065] A vibration test was also carried out on the fixing device according to this embodiment, and the corrugated tube 50 did not come off, and the holding performance was better than that of the bushing 10 according to the first embodiment.

[0066] In this embodiment, the same connecting member can also be used to securely hold a corrugated tube with a smaller diameter. Specifically, a bushing may be manufactured in which the outer diameter of the cone-shaped portion is the same, but the inner diameter (including the outer diameter) of the cylindrical portion is smaller to fit a corrugated tube with a smaller outer diameter.

[0067] In both the bushing 10 according to the first embodiment and the bushing 60 according to the second embodiment, five protrusions are arranged spirally from one end to the other end of the cylindrical portion, and are arranged so that there is no gap between one protrusion and the next protrusion connected to it in the circumferential direction. However, the present invention is not limited to this arrangement. The protrusions may have gaps in the circumferential direction, or may overlap. The circumferential length of the protrusions may also be set to match the shape of the projections and recesses on the corrugated tube 50. [Industrial Applicability]

[0068] The bushing for a corrugated tube and the cable fastener with a corrugated tube of the present invention provide waterproofing by using a connecting member when fastening a cable to equipment, and protection of exposed cables can be achieved simply by inserting the corrugated tube into the bushing, making it highly effective in a variety of equipment fields where cables are connected to equipment. [Explanation of symbols]

[0069] 10, 60 bushing 10a, 60a cylindrical part 10b, 60b Cone-shaped part 10c, 60c protrusion 10d, 60d claw part 10e opening 10f, 60f spiral protrusion 20 Connecting member 21 Cap 21a, 25a female thread 22 sleeve 23 Main body 23a Tsuba 23b Cable holder 23c Mounting part 24 Gasket 25 Lock nut 30 equipment 30a Mounting hole 40 Cable 50 Corrugated tube 50a recess 60e slit 100, 110 Mounting fixture

Claims

1. A cylindrical corrugated tube is used to fix a cable connected to a device to a connecting member that fixes the cable, the cylindrical corrugated tube covering the outer periphery of the cable, a cylindrical portion having an inner diameter dimension larger than an outer diameter dimension of the corrugated tube and an inner diameter portion into which the corrugated tube can be inserted; a cone-shaped portion provided at one end of the cylindrical portion and having a shape that conforms to the inner shape of the cap of the connecting member; a plurality of helical protrusions extending from the other end of the cylindrical portion to a predetermined inner diameter portion, the helical protrusions being shaped to fit into recesses formed in an outer diameter portion of the corrugated tube, and having a plurality of protrusions arranged in a spiral pattern in accordance with the pitch of the recesses; a claw portion protruding toward the center of the inner diameter of the cylindrical portion at the one end side of the cylindrical portion, The bushing for a corrugated tube, wherein the cylindrical portion is elastically deformed in a radially expanding direction by a pressing force when the corrugated tube is inserted.

2. 2. The bushing for a corrugated tube according to claim 1, wherein the plurality of helical protrusions are arranged at the same angle with respect to the cross section of the cylindrical portion.

3. 2. The bushing for a corrugated tube according to claim 1, wherein the cylindrical portion is made of a material having rubber elasticity.

4. 2. The bushing for a corrugated tube according to claim 1, wherein the cylindrical portion is made of a thermoplastic resin material, and the cylindrical portion is provided with a plurality of slits parallel to the cylindrical axis direction.

5. The bushing for a corrugated tube according to any one of claims 1 to 4, a connecting member which is a tubular member through which a cable can be inserted, the connecting member comprising: a main body having a flange, a cylindrical cable holding portion and a cylindrical mounting portion which are provided on both sides of the flange and have male threads formed on the outer circumferential surface; an elastic sleeve which has an insertion hole through which the cable passes and is fitted into the cable holding portion; a cap which is formed with female threads that mesh with the male threads of the cable holding portion; a gasket which seals the mounting portion when inserted into a mounting hole formed in a device; and a lock nut which is formed with female threads that mesh with the male threads of the mounting portion; a corrugated tube that covers and protects the outer periphery of the cable, a corrugated tube-equipped cable fastener, the main body being fixed to the device by the lock nut via the gasket, the cone-shaped portion of the corrugated tube bushing being inserted into the cap, the cap being tightened to deform the sleeve and tightly fix the cable and the cone-shaped portion, and the corrugated tube being inserted into the corrugated tube bushing, and a protrusion on an inner diameter portion of the corrugated tube bushing being fitted into a recess on an outer diameter portion of the corrugated tube to fix and hold the corrugated tube in place.

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