Inner-space-sectioned tubes and method for manufacturing the same

Abstract

An inner-space-sectioned tube wherein, in manufacturing the tube having four or more independent fluid channels formed inside thereof, while at least two lengths of inner tubes are set to inscribe an outer tube, cold working is applied, which is a simple manufacturing process, thereby enabling to reduce the number of cold drawing passes and allowing the inner space of the tube, even if the outer tube is small in size, to effectively be allocated for four independent fluid channels. Further, this inner-space-sectioned tube adopts a simple tube structure wherein the number of constituting members is reduced, thereby enabling to reduce weight while ensuring tube strength and to achieve further reduction of manufacturing costs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating an example of a cross-sectional configuration of a tube having four independent fluid channels within its inner space, which is proposed in Japanese Patent Application Publication No. 7-144221,

FIG. 2 is a cross-sectional view illustrating an alternative example of the cross-sectional configuration of a tube having four independent fluid channels within its inner space, which is proposed in Japanese Patent Application Publication No. 7-144221,

FIG. 3 is a view illustrating an example of a cross-sectional structure of an inner-space-sectioned tube of the present invention,

FIG. 4 is a view explaining a method for manufacturing an inner-space-sectioned tube of the present invention, whereas FIG. 4A illustrates a cross-sectional shape of an inner tube prior to a finishing drawing process, and whereas FIG. 4B illustrates a cross-sectional shape of an outer tube prior to a finishing drawing process, and whereas FIG. 4C illustrates the state as the inner tubes are set inside the outer tube, and

FIG. 5 is a view illustrating a shaft configuration when the inner-space-sectioned tube of the present invention is used as a valve locker shaft.

Claims

1. An inner-space-sectioned tube in which at least two lengths of inner tubes are provided inside an outer tube of a cylindrical round form having the same cross-section over its entire length, comprising: an outer sealing portion being formed such that an outer peripheral surface of said inner tube contacts with said outer tube, the outer sealing portion being partly concentric relative to the inner peripheral surface of the outer tube;an inner sealing portion wherein said inner tubes oppose to and contact with each other;a link segment connecting an end of said outer sealing portion to an end of said inner sealing portion; and,at least one subspace that is enclosed by the link segment of first inner tube, the link segment of second inner tube and a segment of the inner peripheral surface of the outer tube.

2. An inner-space-sectioned tube in which at least two lengths of inner tubes are provided inside an outer tube of a cylindrical round form having the same cross-section over its entire length, comprising: an outer sealing portion being formed such that an outer peripheral surface of said inner tube contacts with said outer tube, the outer sealing portion being partly concentric relative to the inner peripheral surface of the outer tube;an inner sealing portion wherein said inner tubes oppose to and contact with each other;a link segment connecting an end of said outer sealing portion to an end of said inner sealing portion; and,two subspaces that are enclosed by the link segment of first inner tube, the link segment of second inner tube and a segment of the inner peripheral surface of the outer tube.

3. The inner-space-sectioned tube according to claim 2, wherein: said outer sealing portion is made longer in segmental length than said inner sealing portion;a hole-in-communication is provided by machining at said outer sealing portion; and,said link segment extends in a radial direction relative to said outer tube.

4. The inner-space-sectioned tube according to claim 2, wherein four or more independent fluid channels are formed in the inner space of said outer tube.

5. The inner-space-sectioned tube according to claim 3, wherein four or more independent fluid channels are formed in the inner space of said outer tube.

6. The inner-space-sectioned tube according to claim 2, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

7. The inner-space-sectioned tube according to claim 3, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

8. The inner-space-sectioned tube according to claim 4, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

9. The inner-space-sectioned tube according to claim 5, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

10. An inner-space-sectioned tube in which at least two lengths of inner tubes are provided inside an outer tube of a cylindrical round form having the same cross-section over its entire length, comprising: an outer sealing portion being formed such that an outer peripheral surface of said inner tube contacts with said outer tube, the outer sealing portion partly following the contour of the inner peripheral surface of the outer tube;an inner sealing portion wherein said inner tubes oppose to and contact with each other;a link segment connecting an end of said outer sealing portion to an end of said inner sealing portion; and,at least one subspace that is enclosed by the link segment of first inner tube, the link segment of second inner tube and a segment of the inner peripheral surface of the outer tube.

11. The inner-space-sectioned tube according to claim 10, wherein: said outer sealing portion is made longer in segmental length than said inner sealing portion;a hole-in-communication is provided by machining at said outer sealing portion; and, said link segment extends in a radial direction relative to said outer tube.

12. The inner-space-sectioned tube according to claim 10, wherein four or more independent fluid channels are formed in the inner space of said outer tube.

13. The inner-space-sectioned tube according to claim 11, wherein four or more independent fluid channels are formed in the inner space of said outer tube.

14. The inner-space-sectioned tube according to claim 10, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

15. The inner-space-sectioned tube according to claim 11, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

16. The inner-space-sectioned tube according to claim 12, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

17. The inner-space-sectioned tube according to claim 13, constituting a valve locker shaft wherein fluid channels provided therein are used as transport paths for lubrication oils and working fluids.

18. A method for manufacturing an inner-space-sectioned tube in which at least two lengths of inner tubes are provided inside an outer tube of a cylindrical round form having the same cross-section over its entire length, the inner-space-sectioned tube including an outer sealing portion being formed such that an outer peripheral surface of said inner tube contacts with said outer tube and an inner sealing portion wherein said inner tubes oppose to and contact with each other, the method comprising the steps of: inserting and setting at least two lengths of inner tubes into the inside of an outer tube, wherein the outer and inner tubes are prepared beforehand such that the outer tube at least is larger in size than a finished size of the outer tube;applying cold drawing to the above assembled tube to pressure-bond part of the outer peripheral surfaces of said inner tube onto the inner surface of said outer tub to thereby form an outer sealing portion; andhaving first inner tube opposed to second inner tube to pressure-bond with each other, thus forming an inner sealing portion.

19. The method for manufacturing the inner-space-sectioned tube according to claim 18, wherein four or more independent fluid channels are formed in the inner space of said outer tube.

20. The method for manufacturing the inner-space-sectioned tube according to claim 18, wherein the inner-space-sectioned tube thus obtained is used as a valve locker shaft and said fluid channels constitute transport paths for lubrication oils and working fluids.

21. The method for manufacturing the inner-space-sectioned tube according to claim 19, wherein the inner-space-sectioned tube thus obtained is used as a valve locker shaft and said fluid channels constitute transport paths for lubrication oils and working fluids.