JPH1193936A - Waterproof boot for control cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the wear by the interference with a cable side, and simplify the structure with a minor diameter by providing a major diameter cylinder part to be mounted on an outer tube side, a minor diameter cylinder part to be mounted on an inner cable side, and a folded part meandering radially on the inside of the major diameter cylinder part to mutually connect both the cylinder parts. SOLUTION: A boot 10 is formed of a major diameter cylinder part 10a, a minor diameter cylinder part 10b, and a folded part 10c, and the folded part 10c is made to meander radially in S-shape on the inside of the major diameter cylinder part 10a to connect the minor diameter cylinder part 10b to the major diameter cylinder part 10a. All these parts are made of properly flexible rubber. Since the boot 10 is extended and contracted in the same direction in the stroke of a rod 2 to a guide pipe 3, and folded in the outer diameter direction of the rod 2 on the inside of the major diameter part 10a, it is hardly worn by the rubbing with the guide pipe 3 and the rod 2. Although the outer diameter of the major diameter cylinder part 10a forms the maximum diameter of the boot 10, the boot 10 can be made within a small diameter since the outer diameter of the major diameter part 10a is substantially equal to that of the guide pipe 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a waterproof boot for a control cable.

[0002]

2. Description of the Related Art For example, in a remote control mechanism of a transmission, a control cable is used to transmit a shift operation of a cab to a gear shift mechanism of the transmission. The control cable is a cable in which an inner cable is inserted into an outer tube, and bellows boots are attached to waterproof the both ends (Japanese Utility Model Application Laid-Open Nos. 6-49854, 6-257670, and 7-43936). And JP-A-9-42448).

One example will be described with reference to FIG. 7. A control cable (not shown) includes a rod 2 at both ends thereof and a guide pipe 3 for supporting the rod 2 slidably. The rod 2 is connected to the inner cable of the control cable, and the guide pipe 3 is also connected to the outer tube. When the rod 2 is pushed and pulled with respect to the guide pipe 3, the movement is transmitted to the rod on the opposite side via the inner cable sliding on the outer tube, thereby causing the guide pipe to be actuated (pulled) in the opposite direction.

A bellows boot 1 for sealing the space between the rod 2 and the guide pipe 3 as a waterproof measure for the control cable.
Is provided. The bellows boot 1 is formed of rubber in a cylindrical shape that covers a predetermined region extending over the rod 2 and the guide pipe 3. It is attached to the outer periphery of the guide pipe 3 through the large-diameter opening 1c, and is attached to the outer periphery of the rod 2 at the small-diameter opening 1.
d, and a folded portion 1a (bellows portion) meandering in the axial direction is formed in the middle of these.

[0005]

The bellows boots 1 at both ends of the control cable communicate with each other through a gap between the outer tube and the inner cable, but the pressure in the boot 1 due to the stroke of the rod 2 (the inner cable side) is increased. Fluctuations tend to cause swelling and collapse in the bellows portion 1a. Bellows 1a
When the inside (the meandering valley) expands and contracts with the stroke of the rod 2, it is displaced in the axial direction with respect to the guide pipe 3 (the outer tube side). Therefore, when the bellows portion 1a is crushed, the bellows portion 1a is worn due to interference with the guide pipe 3. In addition, the bellows portion 1a may interfere with the rod 2 and be rubbed, causing the boot 1 to be damaged earlier. An air reservoir 1b (damper chamber) is provided adjacent to the bellows portion 1a to prevent deformation due to the movement of the rod 2, but this disadvantageously increases the sacrifice of the peripheral space. In addition, resistance due to air sealed during expansion and contraction is a factor that impairs operability.

The present invention has been made in view of such a problem, and the control cable has an outer tube side (guide pipe) and an inner cable side (rod).
It is an object of the present invention to provide a waterproof boot having a small diameter and a simple configuration, which is less likely to cause abrasion due to interference with the waterproof boot.

[0007]

According to a first aspect of the present invention, in a waterproof boot attached to an end of a control cable and sealing between an outer tube and an inner cable which can slide freely inside the outer tube, a waterproof boot is provided on the outer tube side. It comprises a large-diameter tubular part to be attached, a small-diameter tubular part to be attached to the inner cable side, and a folding part that meanders radially inside the large-diameter tubular part to connect the small-diameter tubular part and the large-diameter tubular part.

In the second invention, means for improving the formability of the large-diameter cylindrical portion in the first invention is added.

[0009]

According to the first and second aspects of the present invention, when the inner cable side strokes with respect to the outer tube side, the prevention boot straddling them also expands and contracts in the same direction. The amount of expansion and contraction is absorbed by the amount of overlap of the folded portion meandering in the radial direction inside the large-diameter cylindrical portion.

At one end of the control cable,
When the inner cable side strokes in the extension direction, the folded portion meandering in the radial direction is pulled out with the stroke in the inner cable side, and the amount of overlap of the meandering is reduced. When the inner cable side strokes in the contracting direction, the fold portion meandering in the radial direction is pushed deep into the large-diameter cylindrical portion, thereby increasing the amount of overlap in meandering.

Since the boot is folded in the outer diameter direction on the inner cable side inside the large-diameter tubular portion by the stroke on the inner cable side, the boot is less likely to be rubbed and worn on the outer tube side and the inner tube side. Even if the large-diameter cylindrical part is crushed inward due to the pressure fluctuation in the boot due to the inner cable side stroke, the folded part meandering inside the large-diameter cylindrical part prevents contact with the inner cable side, There is little wear on that part.

The outer diameter of the large-diameter cylindrical portion is the maximum diameter of the boot. However, since the large-diameter cylindrical portion is substantially equal to the outer diameter of the outer tube, the boot can be accommodated in a small diameter. Further, since there is no need for a conventional air reservoir (a damper chamber for mitigating pressure fluctuations in the boot due to a stroke on the inner cable side), a layout effect of easily securing a peripheral space can be obtained.

Since the volume change (air amount) of the boot due to the stroke on the inner cable side is small, a decrease in operability due to air resistance can be suppressed. In addition, since the expansion and contraction due to the stroke is absorbed by the amount of overlap of the folded portion, compared with the conventional bellows portion, it is absorbed not by the width of the meander but by the length of the meander. The amount of expansion and contraction can be efficiently absorbed. In other words, the folded portion of the boot has a simple configuration and requires a small amount of rubber, so that the cost can be significantly reduced.

According to the second aspect of the present invention, by giving the large-diameter cylindrical portion a high formability, it is possible to prevent the large-diameter cylindrical portion from being bent inside by a stroke on the inner cable side. Therefore, since the boot is folded into the fixed large-diameter tubular portion only from the small-diameter tubular portion, the boot expands and contracts smoothly while maintaining a folded shape having an overlap amount corresponding to a stroke on the inner cable side.

[0015]

1 and 2, a control cable (not shown) includes a rod 2 at both ends thereof and a guide pipe 3 for supporting the rod 2 slidably. The rod 2 is connected to the inner cable of the control cable, and the guide pipe 3 is also connected to the outer tube. When the rod 2 is pushed and pulled into the guide pipe, the movement is transmitted to the opposite rod through the inner cable sliding on the outer tube.

A rod 2 is provided at each end of the control cable.
A waterproof boot 10 is provided to seal between the guide pipe 3 and the waterproof boot 10. The boot 10 covers a predetermined region extending over the rod 2 and the guide pipe 3 from the outside, and includes a large-diameter cylindrical portion 10a, a small-diameter cylindrical portion 10b, and a folded portion 10c. The folded portion 10c is formed so as to meander in an S-shape in the radial direction inside the large-diameter cylindrical portion 10a to connect between the small-diameter cylindrical portion 10b and the large-diameter cylindrical portion 10b.

The whole (the large-diameter cylindrical portion 10a and the small-diameter cylindrical portion 1)
0b and the fold 10c) are made of rubber to have a moderate flexibility. The large-diameter cylindrical portion 10a is fastened to the outer periphery of the guide pipe 3 via the opening 10d, and the small-diameter cylindrical portion 10c is fastened to the outer periphery of the rod 2 via the opening 10e. The boot 10 expands and contracts in the same direction by the stroke of the rod 2 with respect to the guide pipe 3.

The amount of expansion and contraction is absorbed by the increase or decrease in the amount of overlap of the folded portion 10c meandering in an S shape. When the rod 2 strokes from the guide pipe 3 to the extension side, the folded portion 10c meandering in the radial direction is pulled out with the stroke of the rod 2, and the S-shaped overlap amount is reduced as shown in FIG. When the rod 2 strokes on the contraction side to the guide pipe 3, the folded portion 10c meanders in the radial direction.
Is a large-diameter cylindrical portion 10 while significantly deforming the S-shaped meandering.
a, and the S-shaped overlap amount is enlarged as shown in FIG.

In this case, the stroke of the rod 2
Since the boot 10 is folded in the outer diameter direction of the rod 2 inside the large-diameter cylindrical portion 10a, the guide pipe 3 and the rod 2 are folded.
Rubbing and wear are reduced. Due to the pressure fluctuation in the boot 10 due to the stroke of the rod 2 toward the extension side,
Even if the large-diameter cylindrical portion 10a is crushed inward, the large-diameter cylindrical portion 10a
Since the folded portion 10c meandering in the S-shape (the transition stage from FIG. 2 to FIG. 1) prevents the contact with the rod 2, the portion is hardly worn.

The outer diameter of the large-diameter cylindrical portion 10a becomes the maximum diameter of the boot 10. However, since the large-diameter cylindrical portion 10a is substantially equal to the outer diameter of the guide pipe 3, the boot 10 is accommodated in a small diameter. Also,
Since the volume change of the boot 10 due to the stroke of the rod 2 is small and the air resistance is small, light operation of the rod 2 can be ensured. As a result, there is no need for a conventional air pocket (a damper chamber for mitigating pressure fluctuation in the boot due to the stroke of the rod), so that a layout effect that peripheral space can be easily secured can be obtained.

The S-shaped overlap absorbs the expansion and contraction of the rod 2 due to the stroke, so that the conventional bellows (FIG. 7)
Compared to 1a), since the absorption is performed not by the meandering width but by the meandering length, the same amount of expansion and contraction can be efficiently absorbed by a far smaller number of meandering. In other words, the S-shaped fold 10
Since c has a simple configuration and requires a small amount of rubber, the cost can be significantly reduced. In addition, the overlap change amount of the folded portion 10c is approximately 略 of the stroke amount of the rod 2.

3 and 4 show another embodiment, in which the entire boot 10 is made of rubber. The S-shaped folded portion 10c and the small-diameter cylindrical portion 10b are formed to have a sufficient thickness to exhibit appropriate flexibility, and the large-diameter cylindrical portion 10a is formed to have a large thickness in order to enhance the formability. Thereby, since the large-diameter cylindrical portion 10a has improved rigidity, it can be prevented from being folded into the S-shaped folded portion 10c with the stroke of the rod 2.

Therefore, only from the small-diameter cylindrical portion 10b, S
The boot 1 is folded into the fold 10c.
A value of “0” allows the rod to smoothly expand and contract while maintaining an S-shaped folded shape having an overlap amount corresponding to the stroke of the rod 2.

In the embodiment shown in FIGS. 5 and 6, in order to ensure smooth expansion and contraction of the boot 10, the large-diameter cylindrical portion 10a
Is a highly rigid material (for example, hard synthetic resin or metal)
The folded portion 10a and the small-diameter cylindrical portion 10b are formed of a thick rubber exhibiting appropriate flexibility. The end of the folded portion 10c is crimped to the end of the large-diameter cylindrical portion 10c.

In FIGS. 3 and 5, in order to further enhance the elasticity of the boot 10, the small-diameter cylindrical portion 10b is also provided with a means for improving the formability similarly to the large-diameter cylindrical portion 10a. Or made of a hard synthetic resin or metal). 3 and 5, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

[Brief description of the drawings]

FIG. 1 is a mounting state diagram of a waterproof boot showing an embodiment of the present invention.

FIG. 2 is an operation explanatory view of the same.

FIG. 3 is a mounting state diagram of a waterproof boot showing another embodiment.

FIG. 4 is an operation explanatory view of the same.

FIG. 5 is a mounting state diagram of a waterproof boot showing another embodiment.

FIG. 6 is an operation explanatory view of the same.

FIG. 7 is a mounting state diagram showing a conventional bellows boot.

[Explanation of symbols]

 2 Rod (inner cable side) 3 Guide pipe (outer tube side) 10 Waterproof boot 10a Large diameter cylindrical part 10b Small diameter cylindrical part 10c Folded part 10e Large diameter side opening 10d Small diameter side opening

Claims (2)

[Claims] 1. A waterproof boot attached to an end of a control cable for sealing between an outer tube and an inner cable which is slidable inside the outer tube. A waterproof boot for a control cable, comprising: a small-diameter tubular portion attached to the side, and a folded portion connecting the small-diameter tubular portion and the large-diameter tubular portion meandering radially inside the large-diameter tubular portion. . 2. The waterproof boot according to claim 1, further comprising means for improving the formability of the large-diameter cylindrical portion.