WO2007029890A1

WO2007029890A1 - Multiple tube

Info

Publication number: WO2007029890A1
Application number: PCT/JP2006/318436
Authority: WO
Inventors: Hiroji Oda
Original assignee: Junkosha Inc.
Priority date: 2005-09-09
Filing date: 2006-09-11
Publication date: 2007-03-15
Also published as: JP2007071373A; JP4756335B2

Abstract

A multiple tube formed by adjacently arranging a plurality of plastic tubes parallel with each other and joining these adjacent tubes to each other. A plastic wire of roughly fan shape in cross section is installed at least partly in recessed parts formed by the tubes adjacently arranged parallel with each other in the longitudinal direction of the multiple tube. Accordingly even if the multiple tube is bent with a small bend radius, it can retain a higher joining strength to increase kink resistance so as to prevent a kink phenomenon from occurring. Furthermore, when the multiple tube is bent, it can be easily bent by a small force with less dimensional changes of the multiple tube in the lateral and radial directions.

Description

Technical specification

The present invention relates to a multiple tube in which a plurality of tubes made of plastic are juxtaposed and joined. Particularly, the present invention has an excellent joint strength to improve kink resistance, and it is easy with a small force when bending the multiple tube. The present invention relates to a multiple tube that is bent to a small extent and has little dimensional deformation. Background art

Conventionally, for example, in an industrial robot that transports and mounts various parts using compressed air, etc., fluid such as compressed air is supplied or discharged from a compressor that is a driving source for the movable arm of this robot. In order to drive the arm, multiple tubes are used in which multiple plastic tubes are juxtaposed and joined.

Recently, in such industrial robots, as the robot apparatus has become smaller, multiple tubes used in such industrial robots can be bent with a small bending radius within a limited space, or a small bending The tube may be reciprocated for a long time in a state bent at a radius, and in such a case, the tube will be bent when bent or when reciprocated for a long time in a bent state. A kink phenomenon may occur when it is bent halfway. When this kink phenomenon occurs in the tube, the flow of fluid is hindered at the location where the kink phenomenon occurs, or a part of the tube is damaged and the fluid leaks, so that the fluid can be supplied smoothly to the device to which the fluid is supplied. For example, the robot arm moves abnormally. The problem of giving such an adverse effect arises.

In order to solve the problems caused by the occurrence of the kink phenomenon, it is conceivable to increase the thickness of the tube so that the kink phenomenon does not occur. However, if the tube thickness is increased, the weight and outer diameter of the tube will increase, making it difficult to reduce the size of the robotic device, and the flexibility of the tube may be significantly impaired. . Also, if the tube outer diameter is limited, increasing the tube thickness will inevitably narrow the flow path, reducing the fluid supply flow rate, and the required amount required for the movable arm. This causes problems such as the inability to supply the fluid. In order to solve such a problem, the present applicant has disclosed in Japanese Patent Laid-Open No. 2 0 03-1-7 2 4 8 0, a plurality of tubes made of plastics adjacent to each other, and the adjacent tubes are mutually connected. In a joined multiple tube, a monofilament made of plastic is provided in a part of the surface of the multiple tube in the longitudinal direction of the multiple tube, and a multiple tube with improved kink resistance and sliding life is provided. is suggesting.

However, in this multiple tube, a solid cylindrical monofilament is provided in a part of the surface portion of the multiple tube in the longitudinal direction, so the junction between the surface portion of the multiple tube and the monofilament is This is a joint in the line contact state in the longitudinal direction of the multi-tube, and the joint strength between the multi-tube and the monofilament, in other words, the peel strength is not sufficient. There is a possibility that the multiple tube will peel off, and if this peeling occurs, the kink phenomenon is likely to occur, and as a result, the kink resistance of the multiple tube is significantly impaired. However, the kink resistance is still not sufficient, and when bending multiple tubes, the amount of force required to bend is large. With large dimensional change in the width direction and outer diameter of multiple tubes Met.

Further, in the above-described multiple tube, the solid cylindrical monofilament provided in the valley formed by joining the tubes to each other on the surface of the multiple tube is the largest of the multiple tube from the valley. In such a case, the height of the multiple tube may increase, making it difficult to make the multiple tube compact. This may cause contact with the device, which may adversely affect both the multiple tube itself and peripheral devices. Disclosure of the invention

Therefore, the present invention has been made in view of the above problems, and the problem is that a multiple tube in which a plurality of tubes made of plastics are juxtaposed adjacent to each other and adjacent tubes are joined together with a small bending radius. Even when bent, it has an even greater bond strength to improve kink resistance, prevent the occurrence of kinks, and can be easily bent with a small force when bending multiple tubes. The above-mentioned problem is solved by the present invention in providing a multiple tube having a small dimensional change in the width direction and outer diameter of the multiple tube. That is, the multiple tube according to the present invention is a multiple tube in which a plurality of tubes made of plastics are juxtaposed adjacent to each other, and the adjacent tubes are joined to each other. A multiple tube comprising a part of which a linear body made of plastic having a cross section and a substantially fan shape is provided in a longitudinal direction of the multiple tube. Further, the present invention provides that the top of the linear body does not protrude from the maximum diameter of the multiple tube in the recess of the multiple tube formed by the adjacent tubes. The multiple tube as described above, which is arranged.

According to the present invention, as described above, in a multiple tube in which a plurality of tubes made of plastic are arranged adjacent to each other and the adjacent tubes are joined to each other, the tubes arranged adjacent to each other are used. Since at least a part of the formed recess is provided with a linear body made of plastic having a cross-section and a substantially fan shape in the longitudinal direction of the multi-tube, the fan-shaped linear body is formed in the longitudinal direction of the multi-tube. The joint between the tube and the tube can be joined in a surface contact state, and therefore, the joint area can be increased to increase the joint strength, in other words, the peel strength. As a result, even when the multiple tube is bent with a small bending radius, the striate body exerts an extremely large reinforcing effect to prevent local flattening of the tube and significantly increase the kink resistance. The generation of elephants can be prevented and kink resistance can be improved.

Moreover, when the multiple tube is bent, it can be easily bent with a small force compared to the conventional multiple tube provided with a solid cylindrical monofilament, and the local tube Since flattening can be prevented, the dimensional change in the width direction and outer diameter of the multiple tube can be made extremely small. As a result, the cross-sectional shape of the tube is stably maintained, and the flow path is secured. As a result, the fluid supplied into the tube is not adversely affected, and the filaments are not peeled off from the multiple tubes for a very long time, thereby extending the life.

In addition, since the top of the filament is disposed in the recess of the multiple tube formed by the adjacent juxtaposed tubes without protruding from the maximum diameter of the multiple tube, the height of the multiple tube Therefore, the material in the height direction can be reduced and the weight can be reduced as compared with the conventional arrangement of solid cylindrical monofilaments. The tube can be made compact, and multiple tubes can be used. Does not adversely affect the device itself and peripheral devices.

Furthermore, the multiple tube can be bent with a small bending radius by disposing the above-mentioned linear body in a part in the longitudinal direction of the multiple tube, for example, a portion where the multiple tube is bent. In this case, it is possible to obtain the effect of preventing the occurrence of the kinking phenomenon in that portion, and it is possible to reduce the material and the weight as described above. Brief Description of Drawings

FIG. 1 is a cross-sectional view of an essential part of one embodiment of a multiple tube according to the present invention.

FIG. 2 is a cross-sectional view of the main part of the filament used in the multiple tube shown in FIG.

FIG. 3 is a schematic explanatory diagram of a joint strength test of the multiple tube according to the present invention and the multiple tube of the comparative example.

FIG. 4 is a schematic explanatory view of a repulsion stress measurement test of the multiple tube according to the present invention and the multiple tube of the comparative example.

FIG. 5 is a schematic explanatory diagram of a dimensional change measurement test of a multiple tube according to the present invention and a multiple tube of a comparative example. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described based on one embodiment with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an essential part of one embodiment of a multiple tube according to the present invention, and FIG. 2 is a cross-sectional view of an essential part of a filament used in the multiple tube shown in FIG. It should be understood that the figures are used only to illustrate preferred embodiments of the present invention and that the scale of each part is not considered. Referring to FIG. 1, a multi-tube 1 according to the present invention is shown in a cross-sectional view. This multi-tube 1 is a cylindrical tube formed by extruding a plastic such as polyurethane. Two tubes 2 are juxtaposed side by side, and in the longitudinal direction of the tube 2, for example, a heat fusion by a so-called heat gun (not shown) which is a heating device, or a solvent such as tetrahydrofuran (THF) is applied. They are joined together by means such as solvent fusion used.

In the valley portion of the multiple tube 1 formed by juxtaposing the two tubes 2 adjacent to each other, that is, in the concave portion 3, except for both end portions of the tube 2 to which joints are connected, the multiple tube 1 Along the longitudinal direction, for example, a cross section made of plastic such as polyurethane, which is the same as the material of the tube 2, a substantially fan-shaped filament 4 (see Fig. 2) Force Recesses on both sides formed in the multiple tube 1 Each tube 2 is fused and provided with a solvent such as tetrahydrofuran so as to be fitted and accommodated inside. As a result, due to the fan-shaped joining of the wire 4 to the tube 2, the joint 5 between the wire 4 and the tube 2 is not in a line contact state but in a surface contact state in the cross section. The bonding strength between the filament 4 and the tube 2, that is, the peel strength can be extremely increased.

When the filament 4 is provided in the recess 3 along the longitudinal direction of the multiple tube 1, in this embodiment, the filament 4 is fitted in the recess 3 on both sides formed in the multiple tube 1. However, the present invention is not limited to this, and the linear member 4 may be provided on one side of the concave portion 3 formed in the multiple tube 1, and at least the concave portion 3 on one side may be provided. It only has to be provided. When the linear body 4 is provided in the concave portions 3 on both sides, the bonding strength between the linear body 4 and the tube 2, that is, the peel strength can be further increased. Further, when the filament 4 is provided in the recess 3 along the longitudinal direction of the multiple tube 1, at least the multiple tube 1 Can be provided on all or a part of the reciprocating portion along the longitudinal direction of the reciprocating portion.

At this time, it is preferable that the top portion 6 of the wire body 4 is disposed in the recess portion 3 without protruding from the maximum diameter R of the multiple tube 1. As a result, the height dimension of the multi-tubular tube 1 is not increased. Therefore, compared to the conventional arrangement of solid cylindrical monofilaments, the material in the height direction is reduced and the weight is reduced. The number of tubes can be reduced and the number of tubes can be made compact, and the tubes and peripheral devices are not adversely affected.

In this embodiment, the filament 4 is formed by injection molding. However, the molding method may be other molding means, and the material is limited to the same polyurethane as the tube 2 described above. For example, any material having flexibility such as polyester elastomer or nylon elastomer may be used. Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

Example

Using a polyurethane resin, the tube was extruded using a normal extruder, and a cylindrical tube 2 having an inner diameter of 2.5 mm, an outer diameter of 4 mm, and an overall length of 3 OO mm was formed. The two tubes 2 formed in this way are placed side by side and heat-fused in the longitudinal direction of the tubes 2 with a heat gun as a heating device, and the adjacent tubes 2 are joined to each other to make multiple connections. Formed Yubu 1. Next, in the recessed tube 3 formed between the multiple tubes 1, that is, the joined cylindrical tubes 2, a cross-sectional, substantially fan-shaped filament 4 made of polyurethane resin formed by injection molding separately. (Overall length 140 mm, with a radius of about 2.4 mm on the side to fit into the recess 3 in cross section. And has a substantially fan-shaped radius r of about 2.0 mm, a width W of about 2.0 mm, and a height H of about 1.4 mm. See Figure 2. ) Is fused to each tube 2 with a solvent of tetrahydrofuran so as to be accommodated in the recess 3 without protruding from the outer diameter surface of 4 mm, which is the maximum outer diameter of the tube 2. A multiple tube 1 with a striate was created.

Comparative example

The multiple tube prepared as a comparative example is the same as the example except that a solid cylindrical monofilament 3 having an outer diameter of 2 mm is provided instead of the filament 4 used in the multiple tube 1 of the example. Created in the same way.

In addition to conducting a joint strength test, that is, a peel strength test, of the multiple tube 1 of the example and the multiple tube of the comparative example prepared in this way, the repulsive stress and the dimensional change in the width direction and the outer diameter direction of these tubes I investigated.

The test methods and results are shown below.

Bond strength test

The joining strength test was performed on the multiple tubes of the example and the multiple tubes of the comparative example. In this joining strength test, as shown in FIG. 3, a rod 10 is inserted into the hollow portion of each tube of the joined multiple tubes, and a pair of cross-sections in which both ends of the rod 10 are arranged to face each other. Fix to an approximately U-shaped jig 1 1 and pull it from the left and right sides of this jig 1 1 in the direction indicated by the arrows. The tensile strength when each tube of the multiple tube peels is the peel strength, that is, the joint strength. . (Here, the length of the joined multiple tube used as a sample is 25 mm.)

In the test results, the joining strength of the multi-tube 1 with a substantially fan-shaped linear body created as an example was 4 00 to 5 0 ON, whereas the conventional strength created as a comparative example was Multiple cylinders with solid cylindrical monofilament The joint strength of Yub was 2 00 to 30 ON. Therefore, the multiple tube according to the embodiment of the present invention has an even greater bonding strength than that of the multiple tube of the comparative example, and as a result, the kink resistance is improved, and the occurrence of the kink phenomenon occurs. Can be prevented.

Repulsive stress measurement test and dimensional change measurement test

Next, a repulsive stress measurement test and a dimensional change measurement test were conducted on the multiple tube of the example and the multiple tube of the comparative example. This repulsive stress measurement test and dimensional change measurement test will be described with reference to Figs. First, the repulsive stress measurement test will be described. In this repulsive stress measurement test, as shown in Fig. 4, a multi-tube with a length of 14 O mm is sandwiched between a pair of parallel plates 12 and The repulsive stress was measured when the multiple tubes were compressed in the directions indicated by the arrows on both sides, and the compression dimensions were 50 mm, 40 mm, 30 mm and 20 mm. In this case, that is, when the multiple tube is compressed to 50 mm, 40 mm, 30 mm and 20 mm, the dimensional change in the outer diameter direction and width direction of the multiple tube (see Fig. 5) ) Was measured as a dimensional change measurement test, and the results are shown in Table 1.

table 1

As can be seen from Table 1, the multiple tube according to the embodiment of the present invention has a smaller repulsive stress when bent than the multiple tube according to the comparative example. This means that even when a multi-tube is bent, it can be bent easily with a small force. Also, looking at the dimensional change (outer diameter direction and width direction) of the multiple tube when the multiple tube is compressed to each compression dimension, the outer diameter of the multiple tube according to the embodiment of the present invention is as follows. Compared to that of the multiple tube of the comparative example, the original tube outer diameter of 4 O mm is closer and larger than that of the multiple tube of the comparative example. Therefore, the dimensional change in the outer diameter direction of the multiple tube according to the embodiment of the present invention is Less than that of the tube. Further, when the outer diameter of the tube is large as described above, the width dimension of the tube according to the embodiment of the present invention is smaller than that of the tube of the comparative example, and as a result, the width of the tube is reduced. It can be seen that the dimensional change of the direction and outer diameter is decreasing.

In the embodiment of the present invention, a multiple tube composed of two tubes has been described. However, a multiple tube composed of two or more tubes may be used. The number of filaments provided in the recesses between the tubes to be formed can be any number, and it is of course possible to modify or change them. Industrial applicability

The multiple tube according to the present invention is suitably used for supplying or discharging a fluid such as compressed air to equipment such as an industrial robot that transports and attaches various parts using compressed air or the like. .

Claims

The scope of the claims

1. In a multiple tube in which a plurality of tubes made of plastic are juxtaposed, and the adjacent tubes are joined to each other, at least a part of a recess formed by the adjacent juxtaposed tubes has a cross-section, a substantially fan A multi-tube having a linear body made of plastic in the longitudinal direction of the multi-tube.

2. The top portion of the linear member is disposed without protruding from the maximum diameter of the multiple tube in a recess of the multiple tube formed by the adjacent tubes. The multiple tube according to claim 1.