Design of tube hydroforming machine
and its application

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Design of tube hydroforming machine
Basic tube hydroforming process sequence
Prebending

Preforming

Hydroforming

Preforming press

Hydroforming press(Draw bending)

Draw bendingmachineA typical example of machine arrangement
for hydroforming process sequence

Hydroforming press

Preforming press

Draw bendingmachine

Design of draw bending machine (1)Rotational
bending form

Clamp die
MandrelWiper dieCompression booster

Movable pressure die

Pressure die assist booster

Axial compressive force

Compression booster

Pressure die

Forward frictional force

Pressure die assist boosterDesign of draw bending machine (2)Axial compressive force is effective to increase
the thickness of the bend after the subsequenthydroforming.

Compression booster

Pressure die assist booster

Forward frictional force is effective to decrease thereduction of the peripheral length of the bend during
the draw bending.

Design of draw bending machine (3)R1Pressure die

R1

R2

R2

R1

R1

R1

R1

R2

Stacked bending forms for different radiusbends progressively in one part (number ofbending forms: 2～5)R2

An example of draw bending machine in thehydroforming process sequence

Draw bending of tube for an engine cradleDesign of preforming press
Single-purpose press

Multi-purpose press(An example for an engine cradle)
Common plate

Horizontal
cylinders
Die setSlide cylinder

Die setSlidePunch
Die setPunch

Movingbolster

Die setAn example of single-purpose preforming press

Vertical cylinder:1,500KN

Examples of multi-purpose preforming press

2,000KN

3,500KN

Basic composition of hydroforming machine
Pressure intensifier

Die closing press (machine)

Horizontal
cylinders foraxial feeding oftube ends

High pressure
mediumLow pressure
mediumFilterPressure
mediumreservoir

Oil
Oil reservoir

Oilreservoir

Retro-fit hydroforming press
Re-use of hydraulic press as a hydroforming press byadding the horizontal cylinders and pressure intensifier
Pressure intensifier

Equipment for driving
horizontal cylinders

Pressure medium
reservoir

Concept of hydroforming machine
1. Machine type:
Single-purpose press (machine) or
Multi-purpose press
2. Die closing system:
Hydraulic die closing or
Mechanical die closing
3. Material handling:
Loading & unloading in the press oroutside the press

Single-purpose hydroforming press
Features: (1) Fixed target product(2) Compact press size (Height & Area)(3) High productivity

Slide cylinder
with a minimum
force and stroke
necessary to thedie closing

Horizontal cylinder
with a minimum
force and stroke
necessary to theaxial feeding of thetube end

Examples of single-purpose hydroforming press

Die closing force:15,000KN

Die closing force:8,000KN

Multi-purpose hydroforming press (1)Features: (1) Conventional hydraulic press(2) Horizontal cylinders for axial feeding oftube ends are installed in each die set.
Slide cylinder withforce and stroke
necessary toclosing all die sets

Space with area andheight necessary tosetting the largest
die set and handlingthe workpiece

Die set withhorizontal cylinders

Multi-purpose hydroforming press (2)Features: (1) Flexible positioning of horizontal
cylinders on the bed(2) Horizontal cylinders are commonly used
for several die sets.
Horizontal cylinders
BedExamples of multi-purpose hydroforming press(1)Die closing force:35,000KN

Die closing force:35,000KN

Examples of multi-purpose hydroforming press(2)Die closing force:50,000KN

Concept of hydroforming machine
1. Machine type:
Single-purpose press (machine) or
Multi-purpose press
2. Die closing system:
Hydraulic die closing or
Mechanical die closing
3. Material handling:
Loading & unloading in the press oroutside the pressHydraulic die closing(1)Die closing by slide cylinder
Slide cylinder
Slide
Top die
Bottomdie(2)Die closing by table lifting cylinder
Die setTable

Table cylinderMechanical die closing (1)Transverse clamping of top and bottom dies
Top die lifting cylinder
Die-clamping cylinder
Top die

Bottom die

Clamping tool

Cylinders for axialfeeding of tube ends

Mechanical die closing (2)Longitudinal clamping of top and bottom dies
Conical faceTop die lifting cylinderDie

Die holder

Die-clamp ringConcept of hydroforming machine
1. Machine type:
Single-purpose press (machine) or
Multi-purpose press
2. Die closing system:
Hydraulic die closing or
Mechanical die closing
3. Material handling:
Loading & unloading in the press oroutside the pressMaterial handling(1)Loading andunloading in thepress

Sufficient space forloading and unloading
by robot arm(2)Loading andunloading outsidethe press

Minimum space forseparating top andbottom dies

Minimized
machine height
Automatic moving of bottom die

Specifications of hydroforming press
Die closing force
Standard classification

Axial feeding of tube ends
Axial feeding force
Double acting horizontal cylinder

Pressure intensifier
Maximum pressure, Pressure control

Productivity
Parallel forming, Shuttle die

Quick die change system
Moving bolster etc.

Standard classification of die closing force
Class of die
closing force

Automotive parts inmass production(Japan)Exhaust parts～10,000KN Steering parts etc.

15,000KN Sub-frames
A: Vertically projectedarea of die cavity

Die closing force
F≧Pmax×A

FTop die
Bottom diePmax

Cross members
etc.
Perimeter frames

25,000KN Cross members

etc.
Suspension members
35,000KN Engine cradles
Cross members etc.

50,000KN Cross members etc.

Specifications of hydroforming press
Die closing force
Standard classification

Axial feeding of tube ends
Axial feeding force
Double acting horizontal cylinder etc.

Pressure intensifier
Maximum pressure, Pressure control

Productivity
Parallel forming, Shuttle die

Quick die change system
Moving bolster etc.

Axial feeding force of tube end
A1: Area of cross section of tube wall

FapA2: Area of cross section
inside the tube

Internal pressure PPmax

Rough estimation of Fa (max)Fa (max)=A1・σb+A2・Pmax
σb: Ultimate tensile strength of tube
Pmax: Maximum internal pressure
Axial feeding of tube ends

Energy-saving horizontal cylinder
Pressure medium chamber forcompensating the internal pressure

Top die

Bottomdie

Pressure medium
Sealing punch

Hydraulic fluid

PatentedDouble-acting horizontal cylinder
Features: (1) Co-axial inner and outer cylinders(2) Independent feed control
Outer cylinderpressure mediumpath

Inner cylinder
PatentedFunctions of double-acting horizontal cylinder (1)Axial feeding of tube end
by inner cylinder

Axial feeding of die segments
by outer cylinder

Movable die segments
Die segment case
Small corner radiusFunctions of double-acting horizontal cylinder (2)2515Frictional
force isminimized

New method10

φ60.5245mm
φ78.8

50-5-10-15

Tube

Expanding zone

Tube

Distance from the center in mm

210

1801501209060

300-30-90-120-150-180-20-210

Thickness strain in ％20

Conventional method-60

Frictionalforce

Specifications of hydroforming press
Die closing force
Standard classificationAxial feeding of tube ends
Axial feeding force
Double acting horizontal cylinder

Pressure intensifier
Maximum pressure, Pressure control

Productivity
Parallel forming, Shuttle die

Quick die change system
Moving bolster etc.

Pressure intensifier
High pressure medium(Water containing emulsion oil of a few percent)

Maximum pressure
200～400MPa
Pressure
sensorServovalve

High pressurechamber

Hydrauliccylinder

Control of internal pressure with axial feedingof tube ends

Zone not affected by axial feedingof tube ends

Internal pressure

BdBPfCBAC
Small expansion
ratioLarge expansion
ratioPidAdBdA

Axial feeding of tube endA

Specifications of hydroforming press
Die closing force
Standard classification

Axial feeding of tube ends
Axial feeding force
Double acting horizontal cylinder

Pressure intensifier
Maximum pressure, Pressure control

Productivity
Parallel forming, Shuttle die

Quick die change system
Moving bolster etc.

Improvement of productivity by parallel forming
Loading

Loading

Unloading

Unloading

Die set A

Die set B

Cycle-time reduction by shuttle die system
Hydroforming
stage
Unloading& loading
work-piece

Shuttlebottom die

Hydroforming
stageUnloading& loading
work-pieceSpecifications of hydroforming press
Die closing force
Standard classification

Axial feeding of tube ends
Axial feeding force
Double acting horizontal cylinder

Pressure intensifier
Maximum pressure, Pressure control

Productivity
Parallel forming, Shuttle die

Quick die change system
Moving bolster etc.

Quick die change system (1)Moving bolster

Set-up position left

Set-up position right

Traversing direction left-rightSet-up position back

Traversing direction front-backQuick die change system (2)Automatic coupling device
Piping in hydroforming die
Horizontalcylinder(1)Knock-outcylinders
PiercingcylindersDie

Piping in hydroforming machine

Low pressure medium
High pressure medium

Hydraulic fluid forhorizontal cylinder(1)Hydraulic fluid forpiercing cylinders

Die plate

Hydraulic fluid forknock-out cylinders

Horizontalcylinder(2)Hydraulic fluid forhorizontal cylinder(2)Examples of automatic coupling device
Die side
Machine side

Die side

Machine sideThe End