JP2007321989A - Inner cable - Google Patents

Abstract

An inner cable that can be bent with a small radius of curvature and is easy to manufacture without deteriorating buckling strength, load efficiency, sliding resistance, and backlash as compared with a conventional control cable.
SOLUTION: A core 2 comprising a core wire 4 and six side strands 5 twisted around the core wire 4 without spacing in a predetermined direction, covering the core 2, and axially extending on the outer periphery thereof. An inner cable composed of a synthetic resin outer layer 3 in which ten ridges 6 extending straight are provided at equal intervals.
[Selection] Figure 1

Description

    The present invention relates to an inner cable.

JP-A-62-2228708 JP 2000-130427 A JP 2001-140848 A JP-A-10-159832 JP-A-9-88934 JP 11-31418 A

  The control cable includes an outer casing and an inner cable. There is a clearance between the inner cable and the outer casing, which causes backlash in the reciprocating operation of the inner cable. In order to reduce such backlash, it is conceivable to make the clearance between the inner cable and the outer casing as small as possible. In this case, however, the sliding resistance increases and the load efficiency decreases.

  In order to solve such a problem, as shown in FIGS. 5a and 5b, Japanese Patent Laid-Open No. 62-228708 (Patent Document 1) discloses an inner cable 100 having a synthetic resin coating having irregularities 101 on the outer surface, 110 is proposed. Furthermore, Japanese Patent Laid-Open No. 2000-130427 (Patent Document 2) proposes an inner cable provided with a synthetic resin layer having spiral irregularities on its surface. Since these parts reduce the clearance with the outer casing due to the unevenness provided on the surface, and leave the clearance by the groove of the unevenness, the load efficiency is not lowered so much and the sliding resistance is increased so much. Without backlash. Further, Japanese Patent Application Laid-Open No. 2001-140848 (Patent Document 3), Japanese Patent Application Laid-Open No. 10-159832 (Patent Document 4), and the like are known in which an inner cable is provided with a projecting portion or protrusion that extends spirally. ing.

  With the recent reduction in the engine room of automobiles, control cables are required to be bent with a smaller radius of curvature and to improve load efficiency, backlash, and the like.

  The present invention provides a high load efficiency compared to conventional control cables, can be bent with a small curvature radius without deteriorating buckling strength, sliding resistance, and backlash, and is easy to manufacture. The technical challenge is to provide

  The inner cable of the present invention covers a core composed of one core wire and 6-14 side strands twisted around the core wire in a predetermined direction without any gap, and covers the core. And a synthetic resin outer layer provided with three or more and ten or less ridges extending at equal intervals in the axial direction, the radius of curvature of the top of the ridge is 0.2 mm or less, The height is 0.05 to 0.2 mm, and the outer diameter is 1.0 to 4.0 mm (Claim 1). Here, the curvature radius of the ridge top portion being 0.2 mm or less includes not only the arch top portion having an arc shape but also an edge shape. The outer diameter of the inner cable here refers to the diameter of a circle whose radius is a line connecting the center of the core and the top of the ridge. It is preferable that the height of the ridge is 1/100 to 1/10 of the outer diameter of the inner cable. It is preferable that the core is composed of one core wire and six side strands twisted around the core wire in a predetermined direction without being spaced apart, and the outer layer includes ten protrusions ( Claim 3).

  The control cable using the inner cable of the present invention may be composed of the inner cable described above and a cylindrical outer casing that slidably accommodates the inner cable and has a circular cross-section liner on the inner surface. Good. Preferably, the inner cable has an outer layer made of 11 nylon, and the outer casing has a liner made of polyethylene. Preferably, the liner is high density polyethylene and ultra high molecular weight polyethylene.

  Since the inner cable of the present invention (Claim 1) covers the core and is provided with a protrusion extending in the axial direction on the outer periphery thereof, the clearance between the inner cable and the outer casing is reduced by the height of the protrusion. Can do. In addition, since the curvature radius of the top of the ridge is 0.2 mm or less, when the inner cable and the outer casing are in contact with each other, the contact area is smaller, and the contacted portion extends in the moving direction. Dynamic resistance can be reduced. As a result, the sliding resistance can be reduced without deteriorating the backlash value due to the reciprocating operation from the conventional value. Further, the outer layer has an effect as a protective layer because it prevents the core from directly touching the outside. Furthermore, compared to a conventionally known inner cable having the same outer diameter, only the portion of the uneven space formed by the protrusion can be reduced in weight, and the material cost can be reduced.

  Moreover, since the said protrusion is provided in 3 or more and 10 or less at equal intervals, even if an inner cable is bent in any direction, it can slide without contacting in an outer casing and parts other than a protrusion.

  When the height of the protrusion of the inner cable is in the range of 1/100 to 1/10 of the outer diameter of the inner cable (Claim 2), the rigidity of the inner cable is not significantly increased. Is preserved. Moreover, in the case of 1/10 or more, there exists a possibility that a protrusion may deform | transform significantly by operating an inner cable.

  Since the control cable using the inner cable of the present invention uses any one of the inner cables, it can be bent with a small radius of curvature, has high load efficiency, low sliding resistance, and low backlash.

  When the outer layer is composed of an inner cable made of 11 nylon (PA11) and an outer casing having a polyethylene liner, the coefficient of dynamic friction between the two synthetic resins is small, so deterioration due to wear is small. That is, a control cable having excellent load efficiency, sliding resistance, and durability can be realized.

  Further, when the liner is made of high density polyethylene (HDPE) and high molecular weight polyethylene (UHMWPE), since the molecular weight is large, the deterioration due to wear is further reduced, and a control cable having the above-described effects is realized. Can do.

  1 is a perspective view showing an embodiment of the inner cable of the present invention, FIG. 2a is a cross-sectional view of FIG. 1, FIG. 2b is an enlarged view of a main portion of FIG. 2a, and FIGS. FIG. 4 is a cross-sectional view showing another embodiment of the inner cable of the invention, and FIG. 4 is a cross-sectional view showing an embodiment of an outer casing which is a component used together with the inner cable of the present invention. FIG. 5a and FIG. FIG. 6A and FIG. 6B are explanatory views of a durability test of a control cable using the inner cable of the present invention and the inner cable of a comparative example, respectively.

  1 and 2 show an embodiment of an inner cable. The inner cable 1 includes a core 2 and an outer layer 3 coated on the outer peripheral surface of the core 2.

  The core 2 is composed of seven metal strands, and has the same diameter as the core wire 4 twisted without a gap in a predetermined direction around the core wire 4 or less than the core wire 4. It consists of six side strands 5 with a diameter. It is preferable to use a JIS G 3560 SWO-A or SWO-B carbon steel oil tempered wire as the conventional metal wire. The diameter is preferably, for example, about 0.3 to 4.0 mm. The core wire 4 preferably has the same diameter as the side strand or a diameter increased by 0.04 to 0.5 mm. By using such a core 2, it is possible to manufacture an inner cable that can be bent with a small radius of curvature while maintaining sufficient rigidity, and that has high durability against repeated bending. Furthermore, when using metal strands of the same type and diameter, the metal strands used for the core can be unified and the production process can be simplified.

  The outer layer 3 covers the core 2 and is provided with ten ridges 6 extending straight in the axial direction on the outer periphery thereof at equal intervals. The top of the cross-sectional shape of the ridge 6 is an arc having a radius of curvature R as shown in FIG. 2b, and the ridge as a whole has a substantially triangular shape. The radius of curvature R of the top of the ridge 6 is 0.2 mm or less, and particularly preferably 0.1 mm or less. Thereby, when an inner cable and an outer casing contact, those contact areas are small, Furthermore, since the part which has contacted is extended in the moving direction, sliding resistance can be made small. In the present embodiment, the cross-sectional shape of the protrusion is an arc at the top, but may be an edge shape. The height is preferably about 0.05 mm to 0.2 mm, and preferably 1/100 to 1/50 of the outer diameter. In FIG. 1, the number of ridges is represented by ten, but the number is not limited and is three or more. Thereby, even if the inner cable is operated with a small radius of curvature, the sliding resistance does not increase due to the groove between the edges contacting the outer casing. Further, the cross-sectional shape of the ridge is not particularly limited, and may be a substantially rectangular shape, a substantially square shape, a substantially polygonal shape, or the like, but is preferably a substantially triangular shape or a substantially arc shape. As a result, the contact area between the inner cable and the outer casing can be kept small, the sliding resistance is not increased, and the influence of wear and the like can be kept small.

  The outer layer 3 is made of 11 nylon and is covered by extrusion molding around the core 2. The thickness of the outer layer 3 is about 0.2 to 0.4 mm. The outer diameter of the inner cable 1 is preferably about 1.0 to 4.0 mm. As the material of the outer layer 3, in addition to 11 nylon (PA11), polybutylene terephthalate (PBT), polyethylene (PE), polyacetal (POM), polyamide other than 11 nylon (PA), fluororesin, or an elastomer thereof may be used. it can.

  3a and 3b show another embodiment of the inner cable. The inner cable 10 includes a core 11 made of seven metal strands and an outer layer 12, and the outer layer 12 is provided with ten ridges 15 that connect the outer periphery straightly at even intervals. The ridge 15 draws an isosceles triangle that is connected at its base. Since the apex has an edge shape, the contact area can be further reduced. The height is preferably 0.03 mm to 0.2 mm, and is configured to be 1/100 or more of the outer diameter of the inner cable. Other configurations are the same as those of the inner cable 1 of FIG. 2, and the above-described operational effects can be achieved.

  FIG. 4 shows an embodiment of an outer casing used for the inner cable of the present invention. The outer casing 20 includes a liner 21 made of high-density polyethylene (HDPE) or ultra-high molecular weight polyethylene (UHMWPE), and 20 metal strands twisted on the outer peripheral surface of the liner 21 without a gap in a predetermined direction. And a protective layer 24 that covers the shield layer 23 and has a circular outer shape. Further, as the liner 21, polybutylene terephthalate (PBT), polyacetal (POM), polyamide (PA), fluororesin, or an elastomer thereof can be used. The high-density polyethylene referred to here has a weight average molecular weight of 100,000 to 500,000 and a density of 0.94 to 0.97, and ultrahigh molecular weight polyethylene refers to a weight average molecular weight of 1,500,000. It means ~ 3 million.

  It is preferable to use a JIS G 3560 SWO-A or SWO-B carbon steel oil tempered wire as the metal wire 22 as in the prior art. The diameter is, for example, about 0.6 to 0.9 mm. At that time, the inner diameter of the liner of the outer casing is preferably about 0.1 to 0.2 mm larger than the outer diameter of the inner cable. The protective layer 24 is made of polypropylene. However, the material of the protective layer 24 is not limited as long as it can prevent deterioration due to contact with other appliances in the engine room. The outer diameter of the outer casing is preferably about 7.0 to 10.0 mm.

  The form of the core of the inner cable described above is a preferred form when used with a small radius of curvature, and is not particularly limited. If the core is an inner cable formed by twisting a plurality of strands, the configuration is not particularly limited.

  Next, the effect of the control cable using the inner cable of the present invention will be described with examples and comparative examples.

[Example 1 (Inner Cable)] The core of the inner cable of Example 1 has one core wire (material: SWO-A) having a diameter of 1.4 mm and a space in the predetermined direction around the core wire. Fourteen side strands having a diameter of 0.4 mm (material: SWRH62A) were used, and 11 nylon was used for the outer layer. The inner cable has an outer diameter of 3.15 mm, the number of ridges is 10 at regular intervals, the height of the ridges is 0.15 mm, and the radius of curvature of the top of the ridges is 0.1 mm. Formed by extrusion.

[Comparative Example 1 (Inner Cable)] The inner cable of Comparative Example 1 has ten ridges at equal intervals and the height of the ridges so that the inner cable has an outer diameter of 3.18 mm. Was formed by extrusion molding so that the radius of curvature of the top of the ridge was 0.3 mm. Other parts are the same as those of the inner cable of the first embodiment.

  Next, the inner cable of Example 1 and Comparative Example 1 coated with silicone grease and the outer casing having the same configuration as in FIG. 4 and having a liner made of polyethylene and an inner diameter of 3.4 mm are used. The load efficiency, backlash, stroke loss, and no-load sliding resistance were measured. In addition, the measurement was carried out by installing as shown in FIG. 6a in a state where the radius was 200 mm and the total bending angle was 450 °. The load efficiency is measured by applying a load load (W) of 70 and 216 N to one end of the inner cable, and performing a push / pull operation with a stroke distance of 25 mm on the other end with a push / pull force measuring instrument. And the tensile operating force F2. The formula for load efficiency is expressed as: load load (W) / operation force (F) × 100 (%). The stroke loss was measured by fixing one end of the inner cable, applying a load having a magnitude different from 70N and 216N, respectively, and measuring the difference in the amount of movement. The backlash was measured by fixing one end of the inner cable, applying load loads (W) of 20 N and 70 N, respectively, and measuring the amount of movement of the inner cable at that time. The results are shown in Table 1.

  From the results of Table 1, when Example 1 having a radius of curvature of the top of the ridge of 0.1 mm is used, a higher load efficiency is obtained than Comparative Example 1 having a radius of curvature of the top of the ridge of 0.3 mm. It can be seen that the load sliding resistance can be suppressed. In addition, the stroke loss value hardly changed. Although the value of backlash has deteriorated, it is thought that this is because the outer diameters of the inner cables of Example 1 and Comparative Example 1 are different. The backlash depends on the outer diameter of the inner cable, and considering these, it is considered that the backlash value does not change.

  [Example 2 (Control Cable)] The control cable of Example 2 includes an inner cable 1 shown in FIG. 1 and an outer casing 20 shown in FIG. 4. SWO-A having a diameter of 0.80 mm was used for the metal wire of the core 2 of the inner cable 1, and 11 nylon was used for the outer layer 3. Further, the size of the inner cable 1 was formed by extrusion so that the diameter of the circle connecting the apexes of the protrusions was 2.85 mm, and the height of the protrusions was 0.1 mm. The liner 21 of the outer casing 20 was made of high-density polyethylene (HDPE) having a weight average molecular weight of 212,000 and a density of 0.955, and its inner diameter was 3.05 mm. SWRH62A was used for the metal strand 22 of the shield layer 23. Polypropylene resin was used for the outermost layer 24 and its outer diameter was 8.2 mm. The inner cable of Example 1 was inserted into the outer casing 20 by applying silicone grease around it.

  [Example 3 (Control Cable)] The control cable of Example 3 has the same structure as that of Example 2. Polybutylene terephthalate (PBT) is used for the liner of the outer casing, and other configurations are the same as those in the second embodiment.

  Durability was measured using the above control cable. The durability measurement was performed by performing a push-pull operation 500,000 times. The wear amount of the protrusions of the inner cable after the durability measurement was 0.01 to 0.02 mm in both Example 2 and Example 3. The load efficiency and backlash at that time were measured in the same manner as described above, and the results are shown in Table 2. Further, as shown in FIG. 6b, the measurement was performed with the bending angle set at 270 ° and the bending radius set at 80 mm.

  From Table 2, it can be seen that Example 2 using high-density polyethylene as the liner has higher load efficiency, lower no-load sliding resistance, and lower backlash. Furthermore, the amount of change in load efficiency after durability measurement could be suppressed to within 10 percent of the initial value, and the amount of change in no-load sliding resistance and backlash could also be suppressed to a relatively small value.

It is a perspective view which shows embodiment of the inner cable of this invention. 2a is a cross-sectional view of the inner cable shown in FIG. 1, and FIG. 2b is an enlarged view of a main portion. 3a and 3b are sectional views showing another embodiment of the inner cable of the present invention. It is sectional drawing which shows embodiment of the outer casing which is a component of the control cable of this invention. 5a and 5b are cross-sectional views showing a conventionally known inner cable. 6A and 6B are explanatory diagrams of a durability test of a control cable using the inner cable of the present invention and the inner cable of the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner cable 2 Core 3 Outer layer 4 Core wire 5 Side strand 6 Projection 10 Inner cable 11 Core 12 Outer layer 13 Core wire 14 Side strand 15 Projection 20 Outer casing 21 Liner 22 Metal strand 23 Shield layer 24 Protective layer 100 Inner cable 101 Unevenness 110 Inner cable R Radius of curvature F1 Operating force F2 Operating force W1 Load load W2 Load load

Claims (3)

A core composed of one core wire and 6-14 side strands twisted around the core wire in a predetermined direction without a gap;
It consists of an outer layer made of a synthetic resin that covers the core and has three or more and ten or less protrusions extending at equal intervals in the axial direction on the outer periphery,
The radius of curvature of the top of the ridge is 0.2 mm or less,
The height of the protrusion is 0.05 to 0.2 mm;
An inner cable having an outer diameter of 1.0 to 4.0 mm. The inner cable according to claim 1, wherein the height of the protrusion is 1/100 to 1/10 of the outer diameter of the inner cable. The core is composed of one core wire and six side strands twisted around the core wire in a predetermined direction without being spaced apart,
The inner cable according to claim 1, wherein the outer layer includes ten protrusions.