JPH10148279A - Bellows structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good bellows structure wherein external diametric dimension is small suppressed, also high flexibility can be realized, to be applied for a grommet and corrugated tube mounted on a linear body of wire harness or the like in a prescribed wiring route. SOLUTION: A bellows 1 is formed by alternately continuing a mountain fold part 2 corresponding to a peripheral part (external diameter A1) and a bottom fold part 3 corresponding to an internal peripheral part (internal diameter B1), further with a sectional center of the peripheral part displaced from a sectional center of the internal peripheral part. Relating to a sectional center C1 of a peripheral circle (peripheral shape) constituted by the mountain fold part 2, a sectional center C1' of an internal peripheral circle (internal peripheral shape) is not conformed, by forming eccentrically by dimension m, a bellows fold depth corresponding to a difference between the mountain/bottom fold parts 2, 3 is D11 in the upward and D12 in the downward, a size relation of D11>D12 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bellows structure, and more particularly to a bellows structure which is optimally applied to a grommet or a tube for protecting and routing a linear body such as a wire harness.

[0002]

2. Description of the Related Art In recent years, the wiring routes of wire harnesses for vehicles have become more complicated and diversified as electric and electronic devices are mounted on vehicles, and the contact between peripheral parts and wire harnesses is prevented. Wire harness holding parts such as harness protectors for protection, corrugated tubes, and grommets used in places where wire harnesses are routed through vehicle panels are frequently used.

In particular, in a path from a vehicle body, which is a fixed portion, to a side door portion, a rear hatchback door portion (trunk), etc., which is a movable portion, through an opening provided in a vehicle panel, the movable portion has Grommets with bellows are generally used for protection from damage due to expansion and contraction or bending of the wire harness due to opening and closing operations, waterproof protection, and the like.

As an example of a grommet with bellows, as shown in FIG. 6, a grommet 10 has a fixed portion 5 fitted to a fixed vehicle panel and a fixed portion 5 fitted to a movable door panel. , And a bellows 1 having elasticity and flexibility provided between the fixing parts 5 and 5 ′, and the bellows 1 expands and contracts and bends according to the amount of movement of the door panel, and is housed inside. Protects linear objects such as harnesses.

[0005]

The relationship between the shape of the bellows 1 of the grommet 10 and the flexibility (bending radius or bending angle) will be described in detail with reference to FIGS. 7 and 8. FIG. The most common shape of the bellows made of a rubber material is, as shown in FIG. 7A, a mountain-folded portion 2 corresponding to the outer peripheral portion (outer diameter A3) of the bellows 1 and an inner peripheral portion (inner diameter B3). The valley folds 3 are formed alternately and continuously.
FIG. 7B shows bellows 1 ′ having different outer diameters in order to examine the flexibility. In FIG. 7B, the outer diameter of the bellows 1 'is A4 (<A3), and the inner diameter is B4 (= A4).
B3), and the wire harness 4 is assumed to be commonly routed through the inner peripheral portion. Here, the bellows fold depths D3 and D4 formed by the bellows folds 2 and the valley folds 3 are represented by D3 = (A3-B3) for convenience.
/ 2, D4 = (A4-B4) / 2.

The bellows 1 has a large outer diameter dimension A3 and a large fold depth D3. Therefore, as shown in FIG. 8 (a), the bellows 1 are densely compressed inside the bend, and outside the ridges 2 and the valley folds. Since the pitch of the portion 3 expands and extends, the bending radius R
3 becomes smaller, a right angle (90 °) or an acute angle (90 ° or less:
(In fact, a U-shaped) bending angle can be realized.
On the other hand, in the bellows 1 ′, since the outer diameter dimension A4 is small and the fold depth D4 is also small, the mountain fold part 2 and the valley fold part 3 extend completely outside the bend as shown in FIG. Since the limit is reached, the bending radius R4 increases, and a sufficient bending angle cannot be realized. In the grommet in which the equivalent wire harness is penetrated and wired as described above, in the case of FIG. 7A, the outer diameter is increased, but the bendability is good, while in the case of FIG. 7B, the outer diameter is increased. Has the advantages and disadvantages of being small but of poor flexibility. However, when mounting such a grommet with bellows on a vehicle, the outer diameter of the bellows is small in order to solve problems such as interference with peripheral parts, durability of the product, and reliability. It is also desirable that the door panel bend sufficiently when the door panel is closed to reduce the storage space for bellows.

As a wire harness protection part having a bellows structure like a grommet, there is a corrugated tube, which is generally made of polypropylene (PP). Such corrugated tubes are
Since it does not have high elasticity or flexibility like the above-mentioned grommet bellows, it is used for accommodating a trunk portion or a branch line portion of a wire harness and fixing it to a vehicle body.

FIG. 9 shows a general shape of a corrugated tube.
As shown in FIG. 2A, the convex portions 21 corresponding to the outer peripheral portion (outer diameter A5) of the corrugated tube 20 and the concave portions 22 corresponding to the inner peripheral portion (inner diameter B5) are formed alternately and continuously. A wire harness 4 is housed and routed around the periphery.
Since the flexibility of the corrugated tube 20 is determined by the difference D5 between the convex portion 21 and the concave portion 22 corresponding to the above-mentioned bellows fold depth, the elastic modulus of the material constituting the corrugated tube 20, and the like, FIG. As shown in ()), the flexibility of the corrugated tube 20 is extremely low, a predetermined bending radius R5 or less cannot be realized, and the flexibility tends to be poorer as the outer diameter dimension increases. for that reason,
When mounting such a corrugated tube on a vehicle body, a predetermined bending radius is required at a corner portion of the vehicle body, for example, in order to realize a routing path determined at a design stage, but in a conventional corrugated tube, However, there is a problem that it is not possible to cope with the setting of a small bending radius, and it is not possible to route to a corner having a steep angle equal to or smaller than a certain bending radius.

An object of the present invention is to solve the above problems,
To provide a good bellows structure by keeping the outer diameter small and realizing high flexibility, and applying it to a grommet or corrugated tube that mounts a linear body such as a wire harness on a predetermined routing path. It is in.

[0010]

According to a first aspect of the present invention, there is provided a bellows structure in which a mountain-folded portion and a valley-folded portion are alternately continuous on an outer peripheral portion, and have a cylindrical shape. The center of the cross section of the inner peripheral shape formed by the valley folds is eccentric in a predetermined direction with respect to the center of the cross section of the outer peripheral shape formed by the mountain folds.

According to the first aspect of the present invention, since the cross-sectional center of the inner peripheral shape for accommodating the linear body or the like is formed eccentrically with respect to the cross-sectional center of the outer peripheral shape of the bellows. The difference between the mountain fold and the valley fold in the eccentric direction of the circumferential shape, that is, the depth of the bellows fold becomes shallower, and the bellows fold in the direction opposite to the eccentric direction of the inner circumferential shape becomes deeper. The bending radius is maximum for the bend with the shallow side of the fold outside, and the flexibility is low. The bending radius is minimum for the bend with the deep side of the bellows outside, and the flexibility is high. Become. Further, with respect to bending in a direction other than the eccentric direction axis of the inner peripheral shape, a bending radius having a value between the above-described maximum and minimum bending radii can be realized steplessly.

In particular, if the bellows structure of the present invention is applied to a grommet, it is possible to reduce the bending radius of the bellows in the eccentric direction only by eccentricizing the inner peripheral shape with respect to the outer peripheral shape. The bendability can be greatly improved without changing (enlarging) the dimension (outer diameter dimension). Further, if the present invention is applied to a corrugated tube, the bending radius of the corrugated tube in the eccentric direction of the inner peripheral shape is minimized, the bending radius of the corrugated tube in the direction opposite to the eccentric direction of the inner peripheral shape is maximized, and Since the bending radius of the corrugated tube in the other direction can be set steplessly to a radius having a predetermined value between the maximum and minimum radii, the bending radius suitable for the routing route when mounting on a vehicle is extremely large. It can be easily realized.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. FIG. 1 is a diagram showing the basic concept of the bellows structure of the present invention. As shown in FIG. 1 (a), the bellows 1 alternately and continuously form a mountain fold 2 corresponding to an outer peripheral portion (outer diameter A1) and a valley fold 3 corresponding to an inner peripheral portion (inner diameter B1). Have been. The feature of the present invention is that the center of the cross section of the outer peripheral portion and the center of the cross section of the inner peripheral portion are shifted from each other. Specifically, XX shown in FIGS. 1B and 1C
Like the cross section and the YY cross section, the center of the cross section of the inner circumference circle (inner circumference shape) formed by the valley fold portions 3 with respect to the outer circumference circle (outer circumference shape) cross section center C1 formed by the mountain fold portions 2. C
1 'does not coincide with each other, and is formed eccentric by a dimension m below the drawing. Therefore, the fold depth of the bellows corresponding to the difference between the mountain fold 2 and the valley fold 3 is D11 in the upper part of FIG. 1A and D12 in the lower part, and has a magnitude relation of D11> D12. .

In such a configuration, when the right side of the bellows 1 shown in FIG.
As shown in (a), the shallow mountain folds 2 and valley folds 3 of bellows are densely compressed inside the bend, and the deep mountain folds 2 and valley folds 3 are bent outside the bend. Since the pitch is sufficiently expanded and extended, the bending radius R
By making 11 smaller, a bending angle of a right angle (90 °) or an acute angle (90 ° or less) can be realized. On the other hand, FIG.
When the right side of the bellows 1 shown in FIG. 2A is bent upward, as shown in FIG. 2B, the deep mountain folds 2 and the valley folds 3 of the bellows are densely compressed inside the bend. However, since the shallow mountain folds 2 and the valley folds 3 extend completely outside the bend, the bend radius R2 increases, and an obtuse angle (90 ° or more) is realized. Further, when the right side of the bellows 1 shown in FIG. 1A is bent in a direction other than upward or downward, for example, in a direction perpendicular to the drawing, a mountain fold according to the bending direction and the depth of folding of the bellows in that direction. Since the extension and compression of the portion 2 and the valley fold 3 occur, the minimum bending radius R11 and the maximum bending radius R12
Can be obtained, and a predetermined bending angle can be realized. That is, bellows 1
Since the desired bending radius can be set steplessly in accordance with the bending direction, a bellows structure having extremely high design flexibility and versatility can be provided.

Next, a first embodiment in which the basic principle of the present invention is applied to a grommet will be described with reference to FIG. First, the configuration of the grommet will be described with reference to FIG.
As shown in FIG. 2, the grommet 10 has a fixing portion 5 fitted into an opening provided in the vehicle panel, and a cross section of an inner peripheral hole extending vertically from the vehicle panel fixing portion 5 and through which the wire harness 4 penetrates. The bellows 1 is formed so that the center and the center of the cross section of the outer periphery are eccentric, and a holding portion 6 provided at the tip of the bellows 1 and in close contact with the wire harness 4 and fixedly wound with a tape is provided. Here, the eccentric direction of the center of the cross section of the inner peripheral hole is the right direction in the drawing.

According to the grommet 10 having such a configuration, when the tip of the bellows 1 is bent rightward in the drawing as shown in FIG. 3B, the inner peripheral hole is eccentric in the rightward direction in the drawing.
Since the right side of the bellows 1 has a shallow fold and the left side has a deep fold, the right mountain fold and valley fold on the inner side of the bend are densely compressed, while the left mountain fold and valley fold on the outer side of the bend are tightly compressed. The pitch is increased, and the bending radius can be reduced, for example, a bending angle α = 90 ° can be realized.

Therefore, the flexibility can be improved without increasing the outer dimensions of the bellows, so that the bellows can be suitably applied to a grommet in a place where the storage space for the bellows is limited. Next, a second embodiment in which the different principle of the present invention is applied to a corrugated tube will be described with reference to FIGS.

As shown in FIG. 4, the corrugated tube 2
In 0, the convex portion 21 corresponding to the outer peripheral portion (outer diameter A2) and the concave portion 22 corresponding to the inner peripheral portion (inner diameter B2) are alternately continuous, and the sectional center of the inner peripheral portion is different from the sectional center of the outer peripheral portion. It is formed eccentric below the drawing. Therefore, the difference between the convex portion 21 and the concave portion 22 corresponding to the folding depth of the bellows is D21 in the upper part of FIG. 4 and D22 in the lower part, and has a magnitude relationship of D21> D22. The cross-sectional views of the inner peripheral portion and the outer peripheral portion are the same as those shown in FIGS.

In such a configuration, if the right side of the corrugated tube 20 shown in FIG. 4 is bent downward, as shown in FIG. Because of its small size, the lower convex portion 21 and concave portion 22 that is the inner side of the bend is compressed and deformed, and the pitch of the upper convex portion 21 and the concave portion 22 that is the outer side of the bend is expanded and deformed, and the bending radius R21 is reduced. And a minimum bending angle of an acute angle can be realized. When the right side of the corrugated tube 20 shown in FIG. 4 is bent upward, as shown in FIG. 5 (b), the upper convex portion 21 and the concave portion 22 which are bent inside are compressed and deformed, but become bent outside. Since the extension deformation of the lower convex portion 21 and the concave portion 22 reaches the limit, the bending radius R22 increases, and the maximum bending angle of, for example, an obtuse angle can be realized. further,
When the right side of the corrugated tube 20 shown in FIG. 4 is bent in a direction other than upward or downward, that is, at a predetermined angle with respect to the drawing, the elongation and the expansion according to the bending direction and the difference between the convex portion 21 and the concave portion 22 in that direction are performed. Since compression becomes possible, FIG.
As shown in (c), a bending radius R23 having a value between the minimum bending radius R21 and the maximum bending radius R22 is obtained, and an arbitrary bending angle can be realized. FIG. 5C is a cross-sectional view in a direction perpendicular to the drawing when the right side of the corrugated tube 20 shown in FIG. 4 is bent perpendicular to the paper surface.

Therefore, an arbitrary bending radius and bending angle can be set steplessly in accordance with the bending direction without increasing the outer dimensions of the corrugated tube.
When mounting the wire harness on a corner or the like of the vehicle body, the corrugated tube can be routed with a predetermined bending radius by bending the corrugated tube to an angle which is substantially at a bending limit. In addition, since the present invention can be applied favorably to an acute angle portion where wiring was not possible in the past, it is possible to simplify the mounting work of the wire harness and improve the design flexibility.

Although the bellows structure of the present invention has been described using a cylindrical or bellows having a circular cross section as an example, the present invention is not limited to this shape. For example, an elliptical or square cross section may be used. Even if it has, it can be applied favorably. Further, in the present embodiment, a grommet and a corrugated tube for arranging and protecting a linear body such as a wire harness have been described, but the present invention is not limited to this embodiment, and may be applied to a general resin tube or the like. Needless to say, it can be applied well. In addition, when an arbitrary bendability is realized as in the above-described corrugated tube, if a mark such as a mark for associating the bend direction with the bendability (bend radius) is provided as appropriate, the wiring and mounting work of the linear body can be performed. Efficiency can be improved.

[0022]

As described above, according to the first aspect of the present invention, the eccentric direction of the bellows in the eccentric direction is made shallow by eccentricity of the center of the inner shape for housing the linear body with respect to the outer center of the bellows. In addition, since the bending in the direction opposite to the eccentricity can be made deeper, the bending radius can be increased for a bend having a shallower bellows as a bent outer shape, and a bend having a deeper bent portion as a bent outer shape. On the other hand, the bending radius can be reduced. Therefore, by applying a bending structure in which the deep part of the bellows is bent to the grommet, the outer diameter can be suppressed and the flexibility can be improved, so that interference with the grommet storage space and peripheral parts can be achieved. And the problem of vibration noise during traveling can be suppressed, and the durability and reliability of the product can be improved. Also, by applying the configuration of the present invention to a corrugated tube,
Since any bending radius and bending angle can be set steplessly according to the bending direction, the corrugated tube can be bent to an angle that is almost at the bending limit when mounting the wire harness on the corners of the vehicle body. If it is possible to route with a predetermined bending radius, it is possible to simplify the work of mounting the wire harness, and also to reduce the bending radius for acute corners where wiring could not be done conventionally Therefore, the degree of freedom in design can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a basic configuration of a bellows structure according to the present invention.

FIG. 2 is a diagram illustrating a bent state of the bellows structure according to the present invention.

FIG. 3 is a view showing a first embodiment in which the bellows structure according to the present invention is applied to a grommet.

FIG. 4 is a view showing a second embodiment in which the bellows structure according to the present invention is applied to a corrugated tube.

FIG. 5 is a diagram illustrating a bent state of a corrugated tube to which the bellows structure according to the present invention is applied.

FIG. 6 is a view showing an example of a conventional grommet.

FIG. 7 is a diagram illustrating a conventional bellows structure.

FIG. 8 is a diagram illustrating a bent state in a conventional bellows structure.

FIG. 9 is a view for explaining a problem in a conventional corrugated tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bellows 2 Mountain fold part 3 Valley fold part 4 Wire harness (linear body) 5, 5 'Fixed part 6 Holding part 10 Grommet 20 Corrugated tube 21 Convex part 22 Concave part

Claims (1)

[Claims] In a bellows structure having a cylindrical shape in which mountain folds and valley folds are alternately continuous with an outer peripheral portion, a center of a cross section of an inner peripheral shape formed by the valley fold is formed by the mountain fold. A bellows structure, wherein the bellows structure is eccentric in a predetermined direction with respect to the center of the cross section of the outer peripheral shape.