Inner cable and control cable comprising inner cable

Abstract

The purpose of the present invention is to provide an inner cable that has excellent load efficiency even when small in diameter, and a control cable that comprises the inner cable. An inner cable 2 comprises a core cable 21 and a coat layer 22 that covers the core cable 21 and that is formed of a resin material. The diameter d2 of the outer periphery of the core cable 21 is 2 mm or less, the ratio of the film thickness t of the coat layer 22 to the radius r1 of the outer periphery of the inner cable 2 is 2‒20%, and the melt flow rate of the resin material is 1‒50 g per 10 minutes.

Description

Inner cable and control cable with inner cable

[0001] The present invention relates to an inner cable and a control cable including the inner cable.

[0002] Conventionally, for example, a control cable disclosed in Patent Document 1 has been used as a remote control cable for a vehicle. The control cable in Patent Document 1 includes an inner cable and an outer casing that slidably houses the inner cable. In this control cable, in order to reduce the sliding resistance of the inner cable within the outer casing and improve the load efficiency of the inner cable, the inner cable is formed of a core and a resin outer layer that covers the outer periphery of the core, and the outer casing has a resin liner as its innermost layer.

[0003] Japanese Patent Application Laid-Open No. 2007-321989

[0004] For example, control cables used in vehicle seat cables and the like are required to have thinner diameters from the viewpoints of routing ease and cost. As the diameter of control cables is reduced, the diameter of inner cables also needs to be reduced. However, since inner cables are required to have a certain level of breaking strength and elongation, it is necessary to make the core have a certain level of outer diameter or more and to form the outer layer that covers the core as thin as possible. However, the thinner the outer layer, the more difficult it is to form it uniformly around the core, which reduces the required abrasion resistance and durability of the inner cable, and as a result, it becomes difficult to satisfy load efficiency.

[0005] An object of the present invention is to provide an inner cable that has excellent load efficiency even when it is small in diameter, and a control cable that includes the inner cable.

[0006] The inner cable of the present invention is an inner cable comprising a core cable and a coating layer formed of a resin material that covers the core cable, wherein the outer diameter of the core cable is 2 mm or less, the ratio of the film thickness of the coating layer to the outer radius of the inner cable is 2 to 20%, and the melt flow rate of the resin material is 1 to 50 g / 10 min.

[0007] The control cable of the present invention is a control cable comprising the above-mentioned inner cable and an outer casing that slidably houses the inner cable, and the clearance between the inner surface of the outer casing and the outer surface of the inner cable is 5 to 40% of the outer diameter of the inner cable.

[0008] According to the present invention, it is possible to provide an inner cable that has excellent load efficiency even when it has a small diameter, and a control cable that includes the inner cable.

[0009] 1 is a partially cutaway perspective view of a control cable according to an embodiment of the present invention; FIG. 2 is a cross-sectional view of an inner cable of the control cable shown in FIG. 1; FIG. 3 is a cross-sectional view of an outer casing of the control cable shown in FIG. 1; FIG. 4 is a schematic diagram showing an apparatus for measuring load efficiency.

[0010] An inner cable and a control cable including the inner cable according to an embodiment of the present invention will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and the inner cable and the control cable of the present invention are not limited to the embodiment described below.

[0011] In this specification, expressions such as "perpendicular to A" and similar expressions do not refer only to a direction that is completely perpendicular to A, but also refer to a direction that is approximately perpendicular to A. In this specification, expressions such as "parallel to B" and similar expressions do not refer only to a direction that is completely parallel to B, but also refer to a direction that is approximately parallel to B. In this specification, expressions such as "C-shape" and similar expressions do not refer only to a perfect C-shape, but also refer to a shape that visually resembles a C-shape (approximately a C-shape).

[0012] As shown in FIG. 1 , the control cable 1 of this embodiment includes an inner cable 2 and an outer casing 3 that slidably houses the inner cable 2. The control cable 1 can be applied to, for example, a vehicle seat reclining mechanism to transmit an operating force applied to an operating lever, which is an operating unit, to a seat lock, which is an operated unit, that changes the reclined state of the seat. However, the control cable 1 can also be applied to other mechanisms in a vehicle or other mechanisms outside of a vehicle, as long as it is an operating force transmission mechanism that transmits an operating force applied to an operating unit to an operated unit. In particular, the control cable 1 (particularly the inner cable 2) can be suitably applied to an operating force transmission mechanism for a light operating load, such as an operating load of 400 N or less.

[0013] The inner cable 2 slides within the outer casing 3 along an axial direction D1 parallel to the axis X, and transmits an operating force between one end and the other end along the axial direction D1. More specifically, one end of the inner cable 2 along the axial direction D1 is directly or indirectly connected to an operating unit, and the other end along the axial direction D1 is directly or indirectly connected to an operated unit, and transmits the operating force of the operating unit to the operated unit. As shown in FIGS. 1 and 2 , the inner cable 2 includes a core cable 21 and a coating layer 22 that covers the core cable 21. The inner cable 2 can also be used with outer casings other than the outer casing 3 described in this specification, as long as a predetermined clearance can be ensured between the inner surface of the outer casing and the outer surface of the inner cable (for example, a clearance of 5 to 40% of the outer diameter of the inner cable, as described below).

[0014] The core cable 21 is a long, thin metal member extending from one end of the inner cable 2 to the other along the axial direction D1, and constitutes the main body of the inner cable 2. The outer diameter d2 (see FIG. 2 ) of the core cable 21 can be appropriately set within a range in which the inner cable 2 including the core cable 21 can be inserted into an outer casing 3 having a predetermined inner diameter and in which the required breaking strength and elongation can be obtained. For example, from the viewpoint of forming the inner cable 2 so as to have an outer diameter that can be inserted into an outer casing with a small diameter (e.g., an inner diameter of 3.5 mm or less), the outer diameter d2 of the core cable 21 is preferably 2 mm or less, more preferably 1.8 mm or less, and even more preferably 1.6 mm or less. Furthermore, from the viewpoint of obtaining an inner cable 2 having a predetermined breaking strength (e.g., a breaking load of 2100 N or more) and elongation (e.g., 0.2% or less under a load of 500 N), the outer diameter d2 of the core cable 21 is preferably 1 mm or more, more preferably 1.2 mm or more, and even more preferably 1.4 mm or more.

[0015] The core cable 21 may have any desired outer diameter and required breaking strength and elongation, and its configuration is not particularly limited. The core cable 21 may be formed, for example, as a single-strand or multi-strand structure in which multiple stainless steel or steel wires are twisted together. In this embodiment, as shown in FIG. 2 , the core cable 21 includes one core wire 21a, multiple first side wires 21b (six in the illustrated example) twisted around the core wire 21a, and multiple second side wires 21c (twelve in the illustrated example) twisted around the layer formed by the multiple first side wires 21b. In addition to the illustrated example, the core cable may also be formed, for example, by twisting multiple strands (e.g., seven) each formed by twisting multiple wires (e.g., seven) together.

[0016] The coating layer 22 is formed of a resin material and coats the outer periphery of the core cable 21. Coating the core cable 21 with the coating layer 22 improves the sliding properties of the inner cable 2 within the outer casing 3, improving load-bearing efficiency. From the viewpoint of reducing the sliding resistance of the inner cable 2 and achieving a predetermined level of load-bearing efficiency, it is preferable that the ratio of the film thickness t of the coating layer 22 to the outer radius r1 of the inner cable 2 be 2% or more. By setting the ratio of the film thickness t of the coating layer 22 to the outer radius r1 of the inner cable 2 to be 2% or more, the abrasion resistance of the inner cable 2 is also improved. From the same viewpoint, it is more preferable that the ratio of the film thickness t of the coating layer 22 to the outer radius r1 of the inner cable 2 be 4% or more, and even more preferably be 6% or more. From the viewpoint of improving the flexibility of the inner cable 2 and achieving a predetermined or higher load efficiency, the ratio of the film thickness t of the coating layer 22 to the outer radius r1 of the inner cable 2 is preferably 20% or less, more preferably 18% or less, and even more preferably 15% or less. The load efficiency is an index showing the efficiency of the inner cable's ability to transmit load, and is a value expressed as the applied load W / the tensile operating force F × 100 (%) (see FIG. 4). The film thickness t of the coating layer 22 is a value expressed as (the outer radius r1 of the inner cable 2) - (the outer radius r2 of the core cable 21), and the ratio of the film thickness t of the coating layer 22 to the outer radius r1 of the inner cable 2 is a value expressed as (the film thickness t of the coating layer 22) / (the outer radius r1 of the inner cable 2) × 100 (%) (see FIG. 2).

[0017] The coating layer 22 is formed of a resin material having a melt flow rate (MFR) of 1 to 50 g / 10 min from the viewpoint of obtaining an inner cable 2 having a predetermined or higher load efficiency. The reason why the inner cable 2 can obtain a predetermined or higher load efficiency by setting the resin material's MFR to 1 g / 10 min or higher is thought to be because the occurrence of irregularities on the surface of the coating layer 22 during molding can be suppressed. Furthermore, setting the resin material's MFR to 1 g / 10 min or higher facilitates coating the core cable 21 with the resin material, improving the productivity of the inner cable 2. From the same viewpoint, the melt flow rate of the resin material is preferably 5 g / 10 min or higher, more preferably 10 g / 10 min or higher, and even more preferably 15 g / 10 min or higher. The reason why the inner cable 2 can obtain a predetermined or higher load efficiency by setting the resin material's MFR to 50 g / 10 min or lower is thought to be because the occurrence of uneven coating (thickness deviation) of the resin material can be suppressed. Furthermore, setting the melt flow rate of the resin material to 50 g / 10 min or less facilitates coating the core cable 21 with the resin material, improving the productivity of the inner cable 2. From the same perspective, the melt flow rate of the resin material is preferably 45 g / 10 min or less, more preferably 40 g / 10 min or less, and even more preferably 35 g / 10 min or less. Thus, setting the melt flow rate of the resin material of the coating layer 22 to 1 to 50 g / 10 min improves the uniformity of the coating layer 22, resulting in an inner cable 2 with excellent load efficiency even when the inner cable 2 has a small diameter. The melt flow rate is a value measured in accordance with ISO 1133. A desired melt flow rate can be obtained by, for example, appropriately selecting the type of resin material, molecular weight, molecular weight distribution, polymerization conditions (polymerization temperature, polymerization time, type and amount of catalyst), type of additive, processing conditions (processing temperature, shear rate), polymer composition, and the like.

[0018] The resin material contained in the coating layer 22 preferably has a melt flow rate in the range of 1 to 50 g / 10 min and a flexural modulus of 300 to 1200 MPa. By making the flexural modulus of the resin material 300 MPa or higher, the abrasion resistance of the coating layer 22 can be improved. From the same perspective, the flexural modulus of the resin material is more preferably 400 MPa or higher, and even more preferably 500 MPa or higher. Furthermore, by making the flexural modulus of the resin material 1200 MPa or lower, the flexibility of the inner cable 2 can be improved, thereby further improving the load-bearing efficiency. Furthermore, by making the flexural modulus of the resin material 1200 MPa or lower, it becomes easier to coat the core cable 21 with the resin material, thereby improving the productivity of the inner cable 2. From the same perspective, the flexural modulus of the resin material is more preferably 1100 MPa or lower, and even more preferably 1000 MPa or lower. The flexural modulus is a value measured in accordance with ISO 178 at a temperature of 23°C and a bending speed of 5 mm / min. The desired flexural modulus can be obtained by appropriately selecting, for example, the type of resin material, the type of additive, the molecular weight, the molecular weight distribution, the crystallinity, the polymerization conditions (polymerization temperature, polymerization time), the processing conditions (processing temperature, cooling rate), the polymer composition, and the like.

[0019] The resin material contained in the coating layer 22 may have a melt flow rate of 1 to 50 g / 10 min and, optionally, a flexural modulus of 300 to 1200 MPa, and the type is not particularly limited. For example, the resin material is preferably at least one selected from the group consisting of polyester resins, polyamide resins, polyolefin resins, and their respective elastomers. Forming the coating layer 22 from these types of resin materials can further improve the load efficiency of the inner cable 2.

[0020] Examples of polyester-based resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. Examples of polyester-based elastomers include thermoplastic copolyester (TPE-E), thermoplastic polyester elastomer (TPEE), polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), etc. Examples of polyamide-based resins include polyamide (PA), specifically polyamide 6 (nylon 6, PA6), polyamide 11 (nylon 11, PA11), polyamide 66 (nylon 66, PA66), polyamide 12 (nylon 12, PA12), etc. Examples of polyamide-based elastomers include thermoplastic polyamide elastomer (TPE-A), polyamide elastomer (PAE), polyamide block copolymer (PABC), etc. Examples of polyolefin resins include polyethylene (PE), polypropylene (PP), and polybutene-1 (PB-1), and examples of polyolefin elastomers include thermoplastic olefin elastomers (TPE-O) and thermoplastic olefin elastomers (TPO).

[0021] The coating layer 22 is formed using a resin material having a melt flow rate of 1 to 50 g / 10 min and, optionally, a flexural modulus of 300 to 1200 MPa, so long as the ratio of the thickness t of the coating layer 22 to the outer radius r1 of the inner cable 2 is 2 to 20%, and the method for forming the coating layer 22 is not particularly limited. In this embodiment, the coating layer 22 is formed on the outer periphery of the core cable 21 by extrusion molding (in-die molding) a resin material around the core cable 21. By forming the coating layer 22 by extrusion molding (in-die molding), the coating layer 22 is formed such that the resin material fills and fixes the gaps between the outermost wires (second side wires 21c) of the core cable 21, as shown in FIG. 2 . This firmly fixes the coating layer 22 to the core cable 21. Note that the coating layer is sufficient as long as it at least covers the core cable, and may or may not penetrate into the gaps between the outermost wires of the core cable, as in this embodiment. Furthermore, the coating layer may or may not penetrate into the interior of the core cable beyond the gaps between the wires in the outermost layer of the core cable.

[0022] The outer casing 3 slidably houses the inner cable 2. The outer casing 3 is a flexible tubular member extending along the axial direction D1. When the outer casing 3 is installed in a vehicle or other installation location, one end of the outer casing 3 in the axial direction D1 is directly or indirectly connected to an operating unit, and the other end of the outer casing 3 in the axial direction D1 is directly or indirectly connected to an operated unit, and the outer casing 3 is routed along a predetermined routing path. The outer casing 3 guides the inner cable 2 along the routing path.

[0023] The outer casing 3 has a predetermined clearance between the inner surface of the outer casing 3 and the outer surface of the inner cable 2 so that the inner cable 2 can be slidably housed therein. The clearance between the inner surface of the outer casing 3 and the outer surface of the inner cable 2 is not particularly limited as long as the inner cable 2 can slide along the axial direction D1, but it is preferably 5 to 40% of the outer diameter d1 of the inner cable 2. Having the ratio of the clearance to the outer diameter d1 of the inner cable 2 be 5% or more can improve the slidability of the inner cable 2 and improve load efficiency. From the same perspective, the ratio of the clearance to the outer diameter d1 of the inner cable 2 is more preferably 10% or more, and even more preferably 15% or more. Furthermore, having the ratio of the clearance to the outer diameter d1 of the inner cable 2 be 40% or less can improve the abrasion resistance of the inner cable 2. This is thought to be because setting the clearance ratio to 40% or less increases the contact area between the inner surface of the outer casing 3 and the outer surface of the inner cable 2, thereby reducing the surface pressure. From the same viewpoint, it is more preferable that the ratio of the clearance to the outer diameter d1 of the inner cable 2 is 35% or less, and even more preferable that it is 30% or less. Note that the clearance is a value expressed as (inner diameter d3 of the outer casing 3) - (outer diameter d1 of the inner cable 2), and the ratio of the clearance to the outer diameter d1 of the inner cable 2 is a value expressed as {(inner diameter d3 of the outer casing 3) - (outer diameter d1 of the inner cable 2)} / (outer diameter d1 of the inner cable 2) x 100(%).

[0024] The outer casing 3 is not particularly limited in structure as long as it can slidably house the inner cable 2. In this embodiment, the outer casing 3 includes a liner 31 as the innermost layer, as shown in Figures 1 and 3. As shown in the figures, the outer casing 3 may further include a spring layer formed by winding metal wires 32 around the outer periphery of the liner 31 so that no gaps are formed, and a resin protective layer 33 around the outer periphery of the spring layer.

[0025] The liner 31 is formed of a resin material and has a generally cylindrical shape with its inner periphery facing the outer periphery of the inner cable 2. From the viewpoint of improving the sliding properties of the inner cable 2 and improving load efficiency, the liner 31 is preferably formed of at least one selected from the group consisting of polyester-based resins, polyamide-based resins, olefin-based resins, polyacetal resins, and fluororesins. Examples of polyester-based resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). Examples of polyamide-based resins include polyamide 6 (nylon 6, PA6), polyamide 11 (nylon 11, PA11), polyamide 66 (nylon 66, PA66), and polyamide 12 (nylon 12, PA12). Examples of olefin-based resins include polyethylene (PE). Examples of polyacetal resins include polyacetal (POM). Examples of fluororesins include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy resin (PFA), and polyvinylidene fluoride (PVDF).

[0026] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Note that the above-described embodiments mainly describe the invention having the following configurations.

[0027] (1) An inner cable comprising: a core cable; and a coating layer formed of a resin material covering the core cable, wherein the core cable has an outer diameter of 2 mm or less; the ratio of the film thickness of the coating layer to the outer radius of the inner cable is 2 to 20%; and the resin material has a melt flow rate of 1 to 50 g / 10 min.

[0028] (2) The inner cable according to (1), wherein the resin material has a flexural modulus of 300 to 1200 MPa.

[0029] (3) The inner cable according to (1) or (2), wherein the resin material is at least one selected from the group consisting of polyester-based resins, polyamide-based resins, polyolefin-based resins, and their respective elastomers.

[0030] (4) A control cable comprising: the inner cable according to any one of (1) to (3); and an outer casing that slidably houses the inner cable, wherein the clearance between the inner surface of the outer casing and the outer surface of the inner cable is 5 to 40% of the outer diameter of the inner cable.

[0031] (5) The control cable according to (4), wherein the outer casing includes a liner as an innermost layer, and the liner is formed of at least one selected from the group consisting of polyester resin, polyamide resin, olefin resin, polyacetal resin, and fluororesin.

[0032] Examples and comparative examples will be given below to specifically explain the effects obtained by the inner cable 2 of this embodiment and the control cable 1 including the inner cable 2. However, the inner cable and control cable of the present invention are not limited to these examples.

[0033] (Inner Cable) Inner cables of the Examples and Comparative Examples were fabricated with coating layers having the thickness ratios shown in Table 1. The thickness ratio is a value expressed as (thickness of coating layer) / (radius of the outer periphery of the inner cable) × 100 (%) (see FIG. 2). For both the Examples and Comparative Examples, the core cables were fabricated with the configuration shown in FIG. 2, consisting of a single 0.35 mm diameter zinc-plated core wire twisted with six 0.3 mm diameter zinc-plated first side wires, and an outer layer twisted with twelve 0.3 mm diameter zinc-plated second side wires, resulting in a diameter of 1.55 mm. The coating layer was formed by extrusion molding (in-die molding) around the core cable of polyamide (PA), thermoplastic elastomer (TPE), polybutylene terephthalate (PBT), thermoplastic olefin elastomer (TPO), or polyethylene (PE) having the melt flow rate (MFR) and flexural modulus shown in Table 1. The melt flow rate is a value measured in accordance with ISO 1133. The flexural modulus is a value measured in accordance with ISO 178 at a temperature of 23°C and a bending speed of 5 mm / min.

[0034] (Outer Casing) For the outer casings of the examples and comparative examples, outer casings were prepared with their inner diameters adjusted to achieve the clearance ratios shown in Table 1. For both the examples and comparative examples, the outer casings were prepared by winding a rolled, unplated hard steel wire with a diameter of 1.1 mm around the outer circumference of a 0.3 mm thick liner made of polytetrafluoroethylene (PTFE) so that no gaps were formed, and then covering the outer circumference with a 0.5 mm thick polypropylene protective layer, as shown in Fig. 3. The clearance ratio is a value expressed as {(inner circumference diameter of outer casing) - (outer circumference diameter of inner cable)} / (outer circumference diameter of inner cable) x 100 (%) (see Figs. 2 and 3).

[0035] (Load Efficiency Evaluation) To evaluate the load efficiency of the control cable, as shown in Figure 4, the control cable was bent and routed with a curvature radius of 50 mm and a total bending angle of 540°. A spring with a load W of 200 N was connected to one end of the inner cable, and a push-pull measuring device PG was attached to the other end of the inner cable. The push-pull measuring device PG measured the pulling force F when a pulling operation was performed over a stroke distance of 30 mm, and the load efficiency was calculated as the load load W / the pulling force F x 100 (%). In the load efficiency evaluation, a load efficiency of 77% or more was evaluated as "◎", a load efficiency of 77% > load efficiency ≥ 73% was evaluated as "◯", and a load efficiency of 73% > load efficiency was evaluated as "△".

[0036] (Wear Resistance Evaluation) To evaluate the wear resistance of the inner cable, the change in load efficiency after 30,000 repeated push-pull operations was examined in the load efficiency measurement described above. In the wear resistance evaluation, load efficiency retention rate = load efficiency after test / load efficiency before test × 100 (%), and the evaluation was made as follows: a load efficiency retention rate of ≥ 77% was marked as "◎", a load efficiency retention rate of 77% > ≥ 75% was marked as "◯", and a load efficiency retention rate of 75% > ≥ "△".

[0037] (Flexibility Evaluation) To evaluate the flexibility of the inner cable, the flexibility of the coating layer, which affects the flexibility of the inner cable, was examined. The flexibility of the coating layer was evaluated by how the coating layer near the cut end surface was deformed by the impact of the cutting when the inner cable was cut with nippers in a direction approximately perpendicular to the axial direction D1. If the coating layer has high flexibility, it undergoes elastic deformation and no change in appearance occurs, but if the flexibility is low, it undergoes plastic deformation and a change in appearance occurs. In the flexibility evaluation, the appearance of the coating layer near the cut end surface was visually confirmed, and a rating of "◎" was given if no change was observed in the coating layer, a rating of "○" was given if the coating layer was whitened, and a rating of "△" was given if cracks occurred in the coating layer.

[0038] (Productivity Evaluation) In order to evaluate the productivity of the inner cable, the maximum possible production speed of the inner cable was investigated. In the productivity evaluation, a maximum production speed of 30 m / min or more was evaluated as "◎", a maximum production speed of 30 m / min or more was evaluated as "◯", and a maximum production speed of 10 m / min or more was evaluated as "△".

[0039]

[0040] In Table 1, when focusing on the melt flow rate (MFR) of the coating layer of the inner cable, Examples 1 to 8 have a higher MFR of the coating layer and superior load-bearing efficiency compared to Comparative Example 1. All of Examples 1 to 8 have a coating layer with a melt flow rate (MFR) of 1 g / 10 min or more, and it can be seen that excellent load-bearing efficiency can be obtained by setting the MFR of the coating layer to 1 g / 10 min or more. Furthermore, compared to Comparative Example 1, Examples 1 to 8 have a higher MFR of the coating layer and superior productivity of the inner cable. This shows that excellent productivity of the inner cable can be obtained by setting the MFR of the coating layer to 1 g / 10 min or more.

[0041] Looking at the film thickness ratio of the coating layer of the inner cable in Table 1, Examples 1 to 8 have a higher film thickness ratio of the coating layer and have better load-bearing efficiency than Comparative Example 2, and Examples 1 to 8 have a lower film thickness ratio of the coating layer and have better load-bearing efficiency than Comparative Example 3. In all of Examples 1 to 8, the coating layer has a film thickness ratio of 2 to 20%, and it can be seen that by setting the film thickness ratio of the coating layer to 2 to 20%, excellent load-bearing efficiency can be obtained.

[0042] Looking at the flexural modulus of the coating layer of the inner cable in Table 1, Examples 1 to 3 and 5 to 8 have a lower flexural modulus of the coating layer, excellent flexibility, and excellent load-bearing efficiency compared to Example 4 and Comparative Example 1. In all of Examples 1 to 3 and 5 to 8, the coating layer has a flexural modulus of 1200 MPa or less, and it can be seen that by setting the flexural modulus of the coating layer to 1200 MPa or less, excellent flexibility of the inner cable is obtained, and thereby even better load-bearing efficiency is obtained.

[0043] Looking at the clearance ratio of the control cable in Table 1, Examples 1 to 8 have higher clearance ratios and better load efficiency than Comparative Example 3. All of Examples 1 to 8 have a clearance ratio of 5% or more, and it can be seen that by setting the control cable clearance ratio to 5% or more, excellent load efficiency can be obtained. Furthermore, compared to Example 8, Examples 1 to 7 have lower clearance ratios and better wear resistance. All of Examples 1 to 7 have a clearance ratio of 40% or less, and it can be seen that by setting the control cable clearance ratio to 40% or less, excellent wear resistance can be obtained.

[0044] REFERENCE SIGNS LIST 1 control cable 2 inner cable 21 core cable 21a core wire 21b first side wire 21c second side wire 22 coating layer 3 outer casing 31 liner 32 metal wire 33 protective layer D1 axial direction d1 outer diameter (outer diameter) of inner cable d2 outer diameter (outer diameter) of core cable d3 inner diameter (inner diameter) of outer casing F pulling force r1 outer radius of inner cable r2 outer radius of core cable t film thickness of coating layer PG push-pull measuring device W applied load X axis

Claims

1. An inner cable comprising: a core cable; and a coating layer formed of a resin material that covers the core cable, wherein the outer diameter of the core cable is 2 mm or less, the ratio of the film thickness of the coating layer to the outer radius of the inner cable is 2 to 20%, and the melt flow rate of the resin material is 1 to 50 g / 10 min.

2. The inner cable according to claim 1, wherein the resin material has a flexural modulus of 300 to 1200 MPa.

3. The inner cable according to claim 1, wherein the resin material is at least one selected from the group consisting of polyester-based resins, polyamide-based resins, polyolefin-based resins, and their respective elastomers.

4. A control cable comprising the inner cable according to any one of claims 1 to 3 and an outer casing that slidably houses the inner cable, wherein the clearance between the inner surface of the outer casing and the outer surface of the inner cable is 5 to 40% of the outer diameter of the inner cable.

5. The control cable according to claim 4, wherein the outer casing comprises a liner as an innermost layer, and the liner is made of at least one material selected from the group consisting of polyester resin, polyamide resin, olefin resin, polyacetal resin, and fluororesin.

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