Bushings for corrugated tubes and cable fasteners with corrugated tubes

Abstract

To provide a bushing for a corrugated tube, which fixes and holds a corrugated tube to a connecting member while fixing a cable with the connecting member and providing waterproofing. [Solution] A bushing 10 used to secure a cylindrical corrugated tube that covers the outer periphery of a cable to a connecting member for fixing the cable to an equipment, comprising: a cylindrical portion 10a whose inner diameter dimension is larger than the outer diameter dimension of the corrugated tube, allowing the corrugated tube to be inserted into the inner diameter portion; a cone-shaped portion 10b provided at one end of the cylindrical portion and having a shape that follows the inner shape of the cap of the connecting member; a plurality of spiral protrusion portions 10f that are shaped to fit into recesses 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 shape to match the pitch of the recesses; and a claw portion 10d that protrudes toward the center of the inner diameter of the cylindrical portion on the one end side of the cylindrical portion.

Description

[Technical field]

[0001] The present invention relates to a corrugated bushing used for fixing a corrugated tube to a connecting member, and a cable fixing device 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 to protect them from the environment. Such corrugated tubes often have a bellows structure with annular convex and concave portions alternately connected along the length, but some have a spiral structure. The annular convex portions have flat or mountain-shaped tops, and providing these convex and concave portions gives the corrugated tube flexibility. Various materials, such as resin and metal, are used depending on the application. In the case of resin, highly 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 is also called by a registered trademark, 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 equipment, general electrical equipment, waterproof equipment, lighting equipment, various display devices, sensors, limit switches, solenoid valves, pressure switches, distribution boards, control panels, switchboards, operation panels, and various cable wiring work in control centers.

[0005] The connecting members are used in various devices as described above, and for that reason, the inner diameter portion has a predetermined dimension according to the outer diameter and number of cables. Also, even if the inner diameter portion has the same dimensions, 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 whose inner end portion is larger in diameter than the cylindrical portion and located radially inward, and whose inner end portion is connected to one end portion of the cylindrical portion, and whose inner end portion is formed to protrude radially outward from the outer peripheral surface of the cylindrical portion, and has an outer surface facing the cylindrical portion and an inner peripheral surface opposite to 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 portion of the cylindrical portion and the inner end portion of the flange portion, the recess being recessed toward the inner peripheral surface of the inner end portion relative to the outer surface of the inner end portion. It is said that such a shape can improve the waterproofness of a wire harness used in a vehicle (see, for example, Patent Document 1).

[0007] Also, in a connecting member for a corrugated tube comprising a housing having 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 and comprising a sleeve having an elastic member and a locking member facing radially inward and outward, a structure has been disclosed in which the sleeve is formed as an injection molded member in which a plurality of members are bonded together, and which includes a first cylindrical member that constitutes 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 joint body, a waterproof fixing unit, and a crimped part, is disclosed, which is composed of a joint body having a first joint part and a second joint part protruding from both ends, a soft waterproof tube, and a slip-off prevention engagement ring, one end of the soft waterproof tube is formed with a recessed receiving part for fitting the slip-off prevention engagement ring, the inner surface of the soft waterproof tube is formed with an inclined surface for tightening toward one end of the joint body, and the inner peripheral edge of the slip-off prevention engagement ring is separately formed with an arrangement of elastic engagement pieces for tightening the bellows tube, and the peripheral edge of the slip-off prevention engagement ring is formed with a cutout part penetrating in the axial direction, and a waterproof quick coupling for a bellows tube, which has a fitting opening for inserting the bellows tube and is screwed to the second joint part of the joint body, and the inner edge is formed with a pressing surface near the fitting opening, and the pressing surface presses the slip-off prevention engagement ring of the waterproof fixing unit to form a crimped part with a corresponding end face (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 respectively on either side of the flange, with male threads formed on the outer peripheral surfaces of the cable holding portion and the attachment portion, a 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 a female thread which meshes with the male thread of the cable holding portion, and a lock nut which is formed with a female thread which meshes with the male thread of the attachment portion, in which the attachment portion of the gland body is inserted into an attachment hole formed in a wall to which the cable gland is 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 into the cable holding portion (see, for example, Patent Document 4).

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

[0011] [Patent Document 1] JP2020-120443A [Patent Document 2] JP 2009-510993 A [Patent Document 3] Utility model registration No. 3122351 [Patent Document 4] Patent No. 6239696 [Patent Document 5] JP 2007-51680 A 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 to the outer periphery of the corrugated tube, and the annular lip provided on the inner periphery fits to a recess on the outer periphery of the corrugated tube. Furthermore, the corrugated tube is secured to the grommet by tightening it from the outer periphery with a fixing member such as a cable tie or a crimping ring, thereby ensuring waterproofing. In this invention, the corrugated tube is fixed to the grommet with a cable tie or the like, but if the tightening force of the cable tie is weak, the adhesion between the grommet and the corrugated tube may not be sufficient, and waterproofing may not be ensured. Furthermore, the inner diameter of the tubular portion of the grommet and the outer diameter of the corrugated tube must be of a predetermined dimension.

[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 a main part, a second cylindrical member, and a third cylindrical member, and the third cylindrical member is made of a soft elastomer and has a seal lip. This makes it possible to fix the corrugated tube and the housing and provide waterproofing. This invention also has a problem that the inner diameter dimension of the end of the housing and the outer dimension of the corrugated tube are limited to predetermined dimensions because the corrugated tube is fixed to the housing to provide waterproofing.

[0014] The device described in Patent Document 3 is composed of a joint body to which a fixed object is fixed and a crimping part to tighten the bellows tube, and a waterproof fixing unit is provided between the joint body and the crimping part. This waterproof fixing unit is composed of a soft waterproof tube made of rubber and a nylon locking engagement ring, and a recessed receiving part that fits into the locking engagement ring is molded at the end of the soft waterproof tube, and an inclined surface is molded on the inner edge. This device also has the problem that only a tolerance of a predetermined size can be used because the outer diameter of the bellows tube and the inner diameter of the waterproof unit are allowed to fit together.

[0015] In the invention described in Patent Document 4, the diameter of the sleeve is reduced by screwing the cap, thereby closing the gap with the cable and 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 aimed at fixing a cable to equipment using a connecting member to provide waterproofing, nor does it aim to fix the corrugated tube to a connecting member.

[0017] If the cable gland described in Patent Document 4 is used as the connecting member, for example, the rubber sleeve housed inside can be pressed and deformed by tightening the cap, and a force that tightens the cable can be applied. This tightening force brings the cable and the rubber sleeve into close contact, 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 enables the corrugated tube to be fixed and held in place by a connecting member while fixing 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 problems of the conventional art, 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 connection member for fixing the cable to an equipment, and is characterized in that it includes a cylindrical portion whose inner diameter dimension is larger than the outer diameter dimension of the corrugated tube, allowing the corrugated tube to be inserted into its inner diameter portion, a cone-shaped portion provided at one end of the cylindrical portion and having a shape that follows the inner shape of the cap of the connection member, a plurality of helical protrusions that are shaped to be fitted into recesses 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 shape to match the pitch of the recesses, and a claw portion on the one end side of the cylindrical portion that protrudes 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 a bushing for corrugated tubes (hereinafter referred to as the "bushing"), whereby the protrusions of the bushing and the recesses of the corrugated tube fit together and are fixed in place. Because the protrusions are arranged in a spiral shape, the corrugated tube can be easily inserted or removed by simply inserting or removing it into or from the cylindrical portion of the bushing while rotating it. Once inserted, the corrugated tube can be fixed and held in place by fitting the protrusions into the recesses.

[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 depending on the number of helical protrusions. For example, when four helical protrusions are arranged in the circumferential direction, if one helical protrusion is arranged in 1 / 4 of the area of ​​the inner diameter surface of the bushing, the helical protrusions will not overlap with each other, making it easy to insert and remove the corrugated tube. In that case, the circumferential length of the protrusions may be the length obtained by dividing 1 / 4 of the length 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 taking into account the shape of the mold for manufacturing the bushing and the injection molding conditions.

[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 angles with respect to the cross section of the cylindrical portion, the protrusions are arranged symmetrically with respect to the cross section, which makes 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 harder than the cylindrical portion, and the cone-shaped portion may be fixed to the cylindrical portion. With this configuration, the cylindrical portion into which the corrugated tube is inserted and removed has rubber elasticity, so that it is easy to insert and remove a relatively hard corrugated tube. As the material having rubber elasticity, for example, natural rubber or synthetic rubber can be used. The cylindrical shape with the helical projection 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. In addition, rubber elasticity and hardness can be controlled by controlling the amount of carbon black added and the vulcanization conditions as necessary.

[0025] Furthermore, the cylindrical portion is not limited to being made only of a material having rubber elasticity. For example, a double structure may be used in which a first material having 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) cover the first material. With such a structure, the first material mainly deforms during insertion and removal to allow 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 the tube to be fixed and held more stably.

[0026] In the above configuration, the cylindrical portion may be made of a thermoplastic resin material, and may have a plurality of slits formed in parallel to the cylindrical axis direction. The slits are preferably formed except for the corrugated tube insertion opening and the cone-shaped portion of the cylindrical portion, but may be formed only in the area where the helical protrusion is formed. By providing the slits, the resin material is easily deformed in a direction expanding in diameter when the corrugated tube is inserted or removed, so that when the corrugated tube is pushed in while rotating it, the resin material is deformed in such a way that the diameter expands, and the tube can be easily inserted. After the protrusion of the bushing is fitted into the recess of the corrugated tube, the protrusion can be fixed and held by the resin material.

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

[0028] The resin material can be any thermoplastic resin material 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 gasket for sealing the mounting portion when inserted into a mounting hole formed in the equipment; and a lock nut having a female thread that engages with the male thread of the mounting portion; and a corrugated tube for covering and protecting the outer periphery of the cable, the gasket being fixed to the equipment by the lock nut, the cone-shaped portion of the bushing being inserted into the cap, the cap being tightened to deform the sleeve so that the cable and the cone-shaped portion are tightly attached to each other, and the corrugated tube being inserted into the bushing and fixed by fitting a protrusion on an inner diameter portion of the bushing into a recess on the outer diameter portion of the corrugated tube. Specifically, the cable and the cone-shaped portion are closely and fixed to each other means that the sleeve and the cable are closely and fixed to each other, and that the cap and the cone-shaped portion, and the sleeve and the cone-shaped portion are closely and 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 the sleeve is deformed by tightening the cap to seal the outer periphery of the cable and prevent water from entering the inside of the device, and the corrugated tube can be fixed and held simply by inserting it into the bushing. This makes it easy to insert and remove the corrugated tube, and ensures a stable fixation and holding. Effect 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 having waterproof functions, and is therefore highly effective in fields where cables protected by corrugated tubes are connected to equipment for use. [Brief description of the drawings]

[0032] [Figure 1] 1A is a perspective view of a bushing according to a first embodiment, in which (a) is a perspective view seen from a slightly diagonal 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). [Diagram 2] 1A and 1B are diagrams showing the mounting relationship between a connection member, a bushing, and an apparatus according to a first embodiment, in which (a) is an exploded perspective view, and (b) is a photograph showing a side view of the state in which the connection member is mounted on an apparatus. [Diagram 3] FIG. 1 shows the process of attaching a connecting member and a bushing in accordance with the first embodiment, where (a) shows the state in which the main body of the connecting member is fixed to the device with a lock nut, the upper part being a cross-sectional view, the lower part being a side view, and (b) a photograph taken from an angle. [Figure 4] 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. [Diagram 5] FIG. 1 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) 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 6] 10A is a perspective view of a bushing according to a second embodiment, in which (a) is a perspective view seen from a slightly diagonal horizontal direction, (b) is a perspective view seen from diagonally above, and (c) is a view showing the inner diameter portion cut along the cylindrical axial direction of the bushing. [Figure 7] FIG. 11 is an exploded perspective view showing the mounting 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 fits into the protrusion of the bushing, with the upper part being a cross-sectional view and the lower part being a side view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0034] FIG. 1 shows a bushing according to a first embodiment, where (a) is a perspective view seen slightly diagonally from the horizontal direction, (b) is a perspective view seen diagonally from 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 mounting relationship between the connection member, bushing, and device according to the first embodiment, where (a) is an exploded perspective view, and (b) is a photograph showing the state where the connection member is mounted on the device as viewed from the side.

[0036] FIG. 3 is a diagram showing the process of attaching the connecting member and bushing in 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, the upper part is a cross-sectional view, the lower part is a side view, and (b) is 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 after the corrugated tube has been inserted and the recess of the corrugated tube is engaged with 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 of mounting a fastener using the bushing will be described with reference to these drawings.

[0039] The bushing 10 according to the present embodiment is used to fix a cylindrical corrugated tube 50 covering the outer periphery of a cable 40 to a connection member 20 for fixing the cable 40 connected to an apparatus 30, and 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 having a shape that conforms to the inner shape of the cap 21 of the connection member 20, a plurality of helical protrusions 10f that are shaped to be fitted into recesses 50a provided on the outer diameter portion of the corrugated tube 50 from the other end of the cylindrical portion 10a to a preset inner diameter portion and that are formed by providing a plurality of protrusions 10c in a spiral shape in accordance with the pitch of the recesses 50a, and a claw portion 10d on one end side of the cylindrical portion 10a and protruding toward the center of the inner diameter of the cylindrical portion 10a, and the cylindrical portion 10a is characterized in that it is elastically deformed in the radial expansion 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 this embodiment, four helical protrusions 10f are arranged at the same angle, i.e., shifted by 90 degrees, based on 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. The openings 10e are provided to prevent abnormal deformation when the cone-shaped portion 10b is pressed by the deformation of the sleeve 22 and for draining water. Since there is a possibility that water may enter from the opposite side of the corrugated tube, the openings 10e are provided as a countermeasure against this.

[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 projections 10c, and projection height can be set to various dimensions according to the connection member and the corrugated tube. An installation tool 100 for installing the bushing 10 and the connection member 20 to the device 30 and inserting the corrugated tube 50 into the bushing 10 will 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 and 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 circumferential surfaces, a sleeve 22 which has an insertion hole through which the cable 40 passes and is fitted into the cable holding portion 23b and has elasticity, a cap 21 which is formed with a female thread 21a which meshes with the male thread 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 a female thread 25a which meshes with the male thread 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 by 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, respectively, 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 diameter of the corrugated tube 50 to fix and hold it in place.

[0045] The main body 23, the lock nut 25, and the cap 21 may be made of a metal such as brass, or a resin such as polypropylene. The resin is not limited to polypropylene, but may be acrylonitrile butadiene styrene (ABS) or polyamide, or may be a molded resin having increased strength by mixing reinforcing fibers into these resins.

[0046] Since the gasket 24 is used to seal the mounting hole 30a of the device 30 and provide waterproofing, it is preferable to use silicone rubber, which is used in O-ring seals. Furthermore, the sleeve 22 deforms when the cap 21 is screwed in, and presses against the cable 40 from the periphery, providing close contact and waterproofing. In order to maintain waterproofing for a long period of time, it is necessary to maintain the elastic force that tightly fits the cable 40 for a long period of time. To provide such characteristics, silicone rubber may be used like the gasket 24, or nitrile rubber, butylene rubber, etc. may also be used.

[0047] Next, a process for assembling the fixing device 100 will be described, 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 FIGS. 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 device 30 and fixed in place with the lock nut 25 by screwing.

[0049] Next, the bushing 10 is inserted from the side of the cap 21 where the female thread 21a is formed, and the cylindrical portion 10a is exposed from the cap 21 while the cone-shaped portion 10b remains 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. In this state, the cap 21 is screwed firmly. By screwing, the sleeve 22 is pressed and expands in the direction pressing the cable 40, filling the gap between the cable 40 and the sleeve 22. This makes it possible to achieve waterproofing and fix 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 fixed to the connection member 20 (see FIG. 4).

[0050] Next, as shown in Fig. 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 come into contact with the convex portions of the outer diameter of the corrugated tube 50 and repeatedly fit into the concave portions, and when they come into contact with the convex portions, the cylindrical portion elastically deforms in the radially expanding direction. Note that if the corrugated tube 50 is inserted while being rotated, the insertion can be performed smoothly even if it comes into contact with the convex portions because the protrusions 10c are arranged in a spiral shape.

[0051] After confirming that the tip of the corrugated tube 50 has been inserted up to the claw portion 10d of the bushing 10, the projection 10c of the bushing 10 is adjusted to fit into the recess 50a of the corrugated tube 50. This makes it possible to fix and hold the corrugated tube 50 to the connecting member.

[0052] A vibration test was conducted on the fixing device 100 and the equipment 30 with the corrugated tube 50 fixed and held in place, and 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 fix and hold a corrugated tube of a smaller diameter. Specifically, a bushing may be manufactured and used in which the inner diameter dimension (including the outer diameter dimension) of the cylindrical portion is reduced to suit a corrugated tube of a smaller outer diameter while keeping the outer diameter dimension of the cone-shaped portion 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 is a diagram showing a bushing according to a second embodiment, in which (a) is a perspective view seen slightly diagonally from the horizontal direction, (b) is a perspective view seen diagonally from above, and (c) is a diagram showing the inner diameter portion cut along the cylindrical axial direction of the bushing. FIG. 7 is an exploded perspective view showing the mounting relationship between the connection 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, with the upper part being a cross-sectional view and the lower part being a side view. Hereinafter, a bushing according to a second embodiment of the present invention and a method of attaching a fastener using the bushing will be described with reference to these drawings.

[0056] The bushing 60 according to the present embodiment is used to fix a cylindrical corrugated tube 50 covering the outer periphery of the cable 40 to a connection member 20 for fixing the cable 40 connected to an apparatus 30, and is characterized in that it includes a cylindrical portion 60a 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 60b provided at one end of the cylindrical portion 60a and having a shape that conforms to the inner shape of the cap of the connection member, a plurality of helical protrusions 60f formed by helically providing a plurality of protrusions 60c in accordance with the pitch of the recesses 50a from the other end of the cylindrical portion 60a to a preset inner diameter portion, the plurality of protrusions 60c being shaped to be fitted into recesses 50a provided on the outer diameter portion of the corrugated tube 50 and arranged in a spiral manner in accordance with the pitch of the recesses 50a, and a claw portion 60d protruding toward the center of the inner diameter of the cylindrical portion 60a on one end side of the cylindrical portion 60a, and the cylindrical portion 60a is characterized in that it is elastically deformed in the radially expanding direction by 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 a plurality of slits 60e are provided 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, in accordance with 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 the same angle, 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 by mixing reinforcing fibers such as glass fiber and carbon fiber with these resins. Furthermore, the cone-shaped portion 60b of the bushing 60 is preferably molded simultaneously with the cylindrical portion 60a, but they may be manufactured separately and then fixed together by thermocompression or the like.

[0059] The bushing 60 of this embodiment is manufactured by injection molding using polyamide 6 as described above, but the manufacturing method is the same as the commonly used injection molding method, so a description thereof will be omitted. In addition, the outer diameter dimension, inner diameter dimension, length of the cylindrical portion, number of protrusions, etc. of the bushing 60 can be set to various dimensions according to the shapes of the connection member 20, cable 40, and corrugated tube 50 used. An attachment tool 110 for attaching the bushing 60 and the connection 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 and 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 circumferential surfaces, a sleeve 22 which has an insertion hole through which the cable 40 passes and is fitted into the cable holding portion 23b and has elasticity, a cap 21 which is formed with a female thread 21a which meshes with the male thread 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 a female thread 25a which meshes with the male thread of the mounting portion 23c, and a corrugated tube 50 which covers and protects the outer periphery of the cable 40 (see FIG. 7).

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

[0062] The main body 23, the lock nut 25, and the cap 21 may be made of a metal such as brass, or a resin such as polypropylene. The resin is not limited to polypropylene, but may be acrylonitrile butadiene styrene (ABS) or polyamide, or may be a molded resin having increased strength by mixing reinforcing fibers into these resins.

[0063] Since the gasket 24 is used to seal the mounting hole 30a of the device 30 and provide waterproofing, it is preferable to use silicone rubber, which is used in O-ring seals. Furthermore, the sleeve 22 deforms when the cap 21 is screwed in, and presses against the cable 40 from the periphery, providing close contact and waterproofing. In order to maintain waterproofing for a long period of time, the elastic force that tightly fits the cable 40 needs to be maintained for a long period of time. To provide such characteristics, silicone rubber may be used like the gasket 24, or nitrile rubber, butyl rubber, or the like may be used.

[0064] 8 shows the state of the fixing device 110 with the corrugated tube 50 inserted therein, 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 therein, 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 fix and 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 made 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 in a spiral shape from the other end to one 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, but the present invention is not limited to this arrangement. A gap may be provided between the protrusions in the circumferential direction, or conversely, overlapping may be provided. The circumferential length of the protrusions may also be set in accordance with the shape of the projections and recesses of 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 a waterproof function by using a connecting member when fastening a cable to equipment, and protection of the cable exposed to the outside can be achieved simply by inserting the corrugated tube into the bushing, and therefore is highly effective in a variety of equipment fields where cables are connected to equipment for use. [Explanation of symbols]

[0069] 10, 60 Bushing 10a, 60a Cylindrical part 10b, 60b Cone-shaped section 10c, 60c protrusion 10d, 60d claw part 10e opening 10f, 60f spiral protrusion 20 Connection 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 connecting member is used to fix a cylindrical corrugated tube that covers an outer periphery of a cable to a connecting member for fixing the cable to a device, 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 an inner shape of a cap of the connection member; a plurality of helical protrusions each having a shape that is fitted into a recess provided on an outer diameter portion of the corrugated tube from the other end of the cylindrical portion to a preset inner diameter portion, the plurality of protrusions being provided in a helical manner in accordance with the pitch of the recess; a claw portion protruding toward a center of an 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 applied when the corrugated tube is inserted.

2. 2. The bushing for a corrugated tube according to claim 1, wherein the plurality of helical projections are disposed at the same angle with respect to a 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 axial direction.

5. A 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 their outer circumferential surfaces; a sleeve having an insertion hole through which the cable passes and fitted into the cable holding portion, the sleeve having elasticity; a cap having female threads which mesh with the male threads of the cable holding portion; a gasket for sealing the mounting portion when inserted into a mounting hole formed in a device; and a lock nut having female threads which mesh with the male threads of the mounting portion; and a corrugated tube that covers and protects an outer periphery of the cable. a corrugated tube bushing having a protrusion on an inner diameter portion of the corrugated tube bushing fitted with a recess on an outer diameter portion of the corrugated tube, the protrusion being fitted with a recess on an inner diameter portion of the corrugated tube bushing, and the corrugated tube bushing being fitted with a recess on an outer diameter portion of the corrugated tube, the corrugated tube bushing being fitted with a recess on an inner diameter portion of the corrugated tube bushing, the corrugated tube bushing being fitted with a recess on an outer diameter portion of the corrugated tube, the corrugated tube bushing being fitted with a recess on an inner diameter portion of the corrugated tube bushing, the corrugated tube bushing being fitted with a recess on an outer diameter portion of the corrugated tube bushing, the corrugated tube bushing being fitted with a recess on an inner diameter portion of the corrugated tube bushing, the corrugated tube bushing being fitted with a recess on an outer diameter portion of the corrugated tube bushing, the corrugated tube bushing being fitted with a protrusion on an inner diameter portion of the corrugated tube bushing, the corrugated tube bushing being fitted with a recess on an outer diameter portion of the corrugated tube bushing, the corrugated tube bushing being fitted with a recess ... protrusion on an inner diameter portion of the corrugated tube bushing and the corrugated tube bushing being fitted with a recess on an outer diameter portion of the corrugated tube bushing, the corrugated tube bushing being

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