Processing method of tube body, manufacturing method of cylinder device and cylinder device manufactured by the same

a technology of cylinder device and manufacturing method, which is applied in the direction of spring/damper, mechanical apparatus, shock absorber, etc., can solve the problems of increasing work cost, affecting the quality of cylinder body parts, and affecting the quality of cylinder parts, so as to achieve accurate processing of the end portion of the tube body

Inactive Publication Date: 2008-12-25
HITACHI LTD
View PDF3 Cites 23 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011]The present invention has been made in light of the above problem, and it is an object of the present invention to provide a processing method of a tube body, a manufacturing method of a cylinder device and the cylinder device thereof being able to process an end portion of the tube body in a high degree of accuracy without depending on cutting work which generates chips or burrs when processing an inner periphery of the tube body.
[0013]According to a second aspect of the present invention, there is provided a manufacturing method of a cylinder device comprising the steps of: a manufacturing step of manufacturing a cylinder by the processing method of a tube body according to claim 1; an assembling step of assembling interior parts including a piston, a piston rod and a rod guide into the cylinder; and a curling process of curling a tip end portion of the cylinder so as to prevent the interior parts from falling off.
[0014]According to a third aspect of the present invention, there is provided a cylinder device comprising: a cylinder; a rod adapted to be compressed into or extended from one end of the cylinder; a rod guide inserted into the one end of the cylinder so as to support the rod; and a curled portion formed by curling a tip end portion of the cylinder so as to prevent the rod guide from falling off from the cylinder, wherein the cylinder is formed by pressing a mandrel into an end portion of a base tube, and pressing a roller die against the base tube so as to deform an inner-periphery surface of the end portion of the base tube along an outer-periphery surface of the mandrel.
[0015]According to a fourth aspect of the present invention, there is provided a cylinder device comprising: a rod adapted to be compressed into or extended from one end of the cylinder; a rod guide inserted into the one end of the cylinder so as to support the rod; and a curled portion formed by curling a tip end portion of the cylinder so as to prevent the rod guide from falling off from the cylinder, wherein a thickness reduction rate of the one end of the cylinder is 50% or less.
[0016]With the present invention based on the above, it is possible to accurately process the end portion of the tube body without depending on any types of cutting work generating chips or burrs in process of the inner periphery of the tube body.

Problems solved by technology

However, highly precise work will be needed to perform conventional methods in which the end portion of the outer cylinder 2 is processed by cutting work, so that it inevitably requires considerable time and man-hour, resulting in increase of work cost.
Further, there is a risk that chips or burrs produced by the cutting work adhere to the inner surface of the outer cylinder 2, and then enter as foreign materials (contamination) into the hydraulic damper.
Thus, in case of obtaining the predetermined area reduction rate with respect to the hydraulic damper for the strut suspension in which to have a relatively thick outer cylinder (tube body), molding force necessary for the parallel swaging work needs to go over a buckling load of the base tube, being virtually incapable of molding such a hydraulic damper.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Processing method of tube body, manufacturing method of cylinder device and cylinder device manufactured by the same
  • Processing method of tube body, manufacturing method of cylinder device and cylinder device manufactured by the same
  • Processing method of tube body, manufacturing method of cylinder device and cylinder device manufactured by the same

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0044]In the above first embodiment, the mandrel 11 with two steps made by the first forming portion 14 and the second forming portion 15 having different diameters was applied, but the number of the steps provided at the nose of the mandrel 11 is optional. If desired for thinner tubes, only one step may be applied, or if desired for more thick tube, three steps or more can be applied.

[0045]Further, in the embodiments hereinabove described, the pair of the roller dies 22 / 22 facing toward each other is used for the rotation ironing process; however, the number of the roller die 22 to be provided is also optional. Three roller dies 22 may be applied. Here, in case three roller dies 22 or more are applied, those roller dies 22 should be evenly arranged around the base tube 10. In addition, the present invention is applicable with a planetary ball die instead of the roller die.

[0046]In the first embodiment, the roller dies 22 / 22 are shifted along the base tube; however, the present inve...

second embodiment

[0051]In the second embodiment, as the same with the process shown in FIG. 1A, the base portion of the base tube 10 is to be supported by the chuck 21 of the chuck unit 20 provided within the rotation ironing process apparatus while the mandrel 11 is to be supported by a pressurized device (not shown) shiftable relative to the chuck unit 20. This FIG. 1A is thus the retaining process in the present invention. The rotation ironing process apparatus is provided with the pair of roller dies 22 / 22, each of the roller dies 22 / 22 is rotatable and placed to face each other with the base tube 10 retained by the chuck 21 between. The pair of roller dies 22 / 22 is supported by the driving device (not shown), so that each of the pair of roller dies 22 / 22 can come closer toward or away from each other. Further, the roller dies 22 / 22 are shiftable in parallel along the base tube 10. those roller dies 22 / 22 are not directly provided with a driving apparatus but rotated by rotation of the base tube...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
thicknessaaaaaaaaaa
forceaaaaaaaaaa
removing forceaaaaaaaaaa
Login to view more

Abstract

There is provided a processing method of a tube body comprising the steps of a tube-expanding step wherein a base tube is partially retained with a chuck unit having a rotational function, and a mandrel is pressed in to an end portion of the base tube so as to expand the end portion of the base tube; and a rotation ironing step wherein the chuck unit rotates the base tube together with the mandrel a roller die is pressed against an outer-periphery surface of the end portion of the base tube and the roller die is moved with respect to the base tube and in an axial direction thereof so as to deform an inner periphery surface of the end portion of the base tube into a shape corresponding to an external shape of the mandrel.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a processing method of a tube body wherein thickness of an end portion of the tube body is reduced by plastic working so as to finish in a predetermined dimension, a manufacturing method of a cylinder device using the processing method, and the cylinder device manufactured by the same.[0003]2. Description of the Related Art[0004]For example, as regards a hydraulic damper (shock absorber) of a twin tube type, as shown in FIGS. 11 and 12, an inner cylinder 1 slidably housing a piston 8 is introduced into an outer cylinder 2 with a base. One end of a piston rod 3, opposite to the other end connected to the piston 8, is inserted into a rod guide 4 and an oil seal 5 both installed in an open end of the inner cylinder 1 and the outer cylinder 2 so as to extend outside. According to extension and compression movement of the piston rod 3, damping force will be generated by flow resistance of hyd...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(United States)
IPC IPC(8): B21D39/08
CPCB21D22/16B21D41/021Y10T29/494F16F9/3235F15B15/1438
Inventor MINOGUCHI, KAZUNORI
Owner HITACHI LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap