The present invention relates to a method and a device for manufacturing a separator for a polymer electrolyte fuel cell.
Generally, a polymer electrolyte fuel cell generally uses, as fuel, pure hydrogen or a hydrogen gas acquired by reforming alcohols, and generates electricity by electrochemically controlling a reaction of the hydrogen with oxygen in the air.
The polymer electrolyte fuel cell, which uses a solid, organic, hydrogen ion permselective membrane as an electrolyte, can be compactified as compared to conventional alkaline, phosphoric acid, molten carbonate, solid oxide or other fuel cells using an aqueous, fused salt electrolyte or other fluid medium as an electrolyte, and is under development for electric vehicles and other applications.
The polymer electrolyte fuel cell used has, as shown in
It is conventionally assumed that the separator 1 has a flat margin and a central bulge with a number of convexes and concaves 1a and 1b formed by press forming. However, actually attempted processing of a material made of sheet metal to be formed reveals that the press forming into the shape described above has difficulty since ductile fracture may occur in the bulge with the formed convexes and concaves 1a and 1b. Moreover, attempt of mass manufacturing the separators 1 by press forming will problematically reduce the production efficiency.
In order to overcome the problems, it is recently proposed to oppositely arrange a pair of rolls having surfaces with forming areas with created convexes and concaves and to introduce and pressurize a material made of sheet metal to be formed between the rolls, thereby continuously manufacturing a separator 1 with passages (hydrogen, air and cooling water passages 7, 8 and 9) formed correspondingly to the concaves and convexes on the rolls.
A state-of-the-art technology of a device for manufacturing a separator 1 for a polymer electrolyte fuel cell as shown in
However, it has been still demanded to form or shape a material made of stainless steel or other sheet metal to be formed with high accuracy and more and more thinly (to a thickness of 0.1 mm or so) for the separator 1. Mere utilization of a rolling device would fail in acquiring a requested accuracy due to play between a housing for rolls and main bearing axle boxes and that between the rolls and main bearings.
The invention was made in view of the above and has its object to provide a method and a device for manufacturing a separator for a polymer electrolyte fuel cell capable of forming a material made of sheet metal to be formed with high accuracy and without deteriorated production efficiency, and efficiently manufacturing the separator with high accuracy.
The invention is directed to a method for producing a separator for a polymer electrolyte fuel cell wherein a material made of sheet metal to be formed is introduced and pressurized between a pair of rolls circumferentially alternately having a forming area with concaves and convexes created on a surface and a non-forming area with no concaves and convexes, thereby continuously manufacturing the separator with passages formed corresponding to the concaves and convexes of the rolls, characterized in that
before start of forming, with play in vertical and horizontal directions between a housing and main bearing axle boxes for said rolls being eliminated by an operation of full-time play eliminating cylinders, a gap between the rolls is retained greater than a setting value and play between the rolls and main bearings is eliminated by an operation of non-forming-time play eliminating cylinders;
in this state, push-up cylinders are extended to make the gap between the rolls into the setting value; and upon generation of forming load due to the introduced material between the rolls which is determined as entering into a forming area, the material is formed with pressures of the non-forming-time play eliminating cylinders being set to 0;
upon the forming loads turning to 0 which is determined as entering into a non-forming area, said push-up cylinders are retracted to make the gap between the rolls greater than the setting value, and the play between the rolls and the main bearings is eliminated by the operation of the non-forming-time play eliminating cylinders;
the gap between the rolls is then made into the setting value again by extension of the push-up cylinders; and upon generation of the forming load which is determined as entering into the forming area, the material is formed with the pressures of said non-forming-time play eliminating cylinders being set to 0;
subsequently, the elimination of the play between the rolls and the main bearings in the non-forming area and the forming of the material in the forming area are repeated while the play between the housing and the main bearing axle boxes is always eliminated.
The invention is directed also to a device for producing a separator for a polymer electrolyte fuel cell wherein a material made of sheet metal to be formed is introduced and pressurized between a pair of rolls circumferentially alternately having a forming area with concaves and convexes created on a surface and a non-forming area with no concaves and convexes, thereby continuously manufacturing the separator with passages formed corresponding to the concaves and convexes of the rolls, characterized in that it comprises
push-up cylinders capable of adjusting a gap between said rolls,
full-time play eliminating cylinders arranged between a housing for said rolls and main bearing axle boxes for eliminating play in vertical and horizontal directions,
auxiliary bearings fitted to necks of said rolls,
non-forming time play eliminating cylinders arranged between said auxiliary bearings for eliminating play between said rolls and the main bearings,
load sensors for sensing forming loads and
a controller for outputting operational signals to said push-up, full-time play eliminating and non-forming-time play eliminating cylinders, respectively, on the basis of the forming loads sensed by said load sensors, whereby elimination of the play between the rolls and the main bearings in the non-forming area and forming of the material in the forming area are repeated while the play between the housing and the main bearing axle boxes is always eliminated.
According to the above-mentioned means, the following effects are acquired.
The play between the housing and the main bearing axle boxes for the rolls is eliminated by the operation of the full-time play eliminating cylinders and the play between the rolls; the main bearings is eliminated by the operation of the non-forming-time play eliminating cylinders; and the gap between the rolls can be retained at the setting value with high accuracy. As a result, even if the material is made of extremely thin sheet metal, the accuracy required for the forming is acquired to enable the efficient manufacturing of the separator with high accuracy.
In the device for manufacturing the separator for the polymer electrolyte fuel cell, it is effective for transmitting a rotative force to the rolls with a play of a rotative power transmission system minimized in the rotational direction that roll shafts of the rolls are directly coupled to separate servo motors through reduction gears including their respective strain wave gearing mechanisms and said reduction gears are directly coupled to the corresponding main bearing axle boxes.
A method and a device for manufacturing a separator for a polymer electrolyte fuel cell of the invention can achieve excellent effects that a material made of sheet metal to be formed can be formed with high accuracy without deteriorated production efficiency and a separator can be efficiently produced with high accuracy.
a is an elevation for explaining a principle of a strain wave gearing mechanism of a reduction gear applied to the device for manufacturing a separator for a polymer electrolyte fuel cell of
b is an elevation for explaining the principle of the strain wave gearing mechanism of the reduction gear applied to the device of
c is an elevation for explaining the principle of the strain wave gearing mechanism of the reduction gear applied to the device of
An embodiment of the invention will be described with reference to the accompanying drawings.
In the embodiment, the forming and non-forming areas are circumferentially alternately formed on the roll 13 by fitting two arc-shaped dies 14 each having the forming area with the concaves 14a and the convexes 14b created on the surface onto a roll body 13a of the roll 13 with keys 15 and bolts or other fastening members 16.
Arranged in a lower portion of the housing 10 are push-up cylinders 17 capable of adjusting a gap between the rolls 13 by pushing up and down the main bearing axle boxes 11 of the roll 13 on the lower side. Arranged between the housing 10 and the main bearing axle boxes 11 of the rolls 13 are full-time play eliminating cylinders 18 and 19 (see
The non-forming-time play eliminating cylinder 21 is interposed between half-divided auxiliary bearing covers 22 attached to cover the outer circumferences of the auxiliary bearings 20.
Roll shafts 13c of the respective rolls 13 are directly coupled to separate servo motors 26 through reduction gears 25 with their respective strain wave gearing mechanisms, which are so-called harmonic drives (registered trademark), and the reduction gears 25 are directly coupled to the corresponding main bearing axle boxes 11.
As shown in
For example, when the wave generator 27 rotates clockwise in
Backlash of the reduction gear 25 itself, which directly affects rotational variations of the roll 13, must be minimal. Since the reduction gear 25 with the strain wave gearing mechanism is a reduction gear having extremely minimal backlash as described above, play of the rotative power system (variation in rotative phase difference) are reduced by the reduction gear 25 to a negligible level in the invention.
Further in the embodiment, as shown in
An operation of the embodiment will be described.
First, in a preparatory stage before start of the forming, the controller 24 outputs the operational signals 18a and 19a which set the pressure of the full-time play eliminating cylinders 18 and 19 to P0; with the play in the vertical and horizontal directions being thus eliminated between the housing 10 and the main bearing axle boxes 11 for the rolls, the controller 24 outputs the operational signals 17a which retract the push-up cylinders 17 to retain the gap between the rolls 13 greater than the setting value ga, and outputs the operational signals 21a which set the pressure of the non-forming-time play eliminating cylinders 21 to P0 to eliminate the play between the rolls 13 and the main bearings 12; in this state, the controller 24 outputs the operational signals 17a which set the extension amount of the push-up cylinders 17 to St to set the gap between the rolls 13 to the setting value ga.
When the material 1A made of sheet metal to be formed (see
When the forming load 23a subsequently turns to zero, it is determined as entering into the non-forming area and the controller 24 outputs the operational signals 17a which retract the push-up cylinders 17 to change the extension amount from St to S1 to expand the gap between the rolls 13 to g1 which is greater than the setting value ga, and outputs the operational signals 21a which set the pressure of the non-forming-time play eliminating cylinders 21 to P0 to eliminate the play between the rolls 13 and the main bearings 12; and the controller 24 outputs the operational signals 17a which increase the extension amount of the push-up cylinders 17 from S2 to St again to set the gap between the rolls 13 to the setting value ga.
When the forming load 23a is generated, it is determined as entering into the forming area and the controller 24 outputs the operational signals 21a which change the pressures of the non-forming-time play eliminating cylinders 21 from P0 to 0 to cause the forming of the material 1A. Subsequently, the elimination of the play between the rolls 13 and the main bearings 12 in the non-forming area and the forming of the material 1A in the forming area are repeated while the play between the housing 10 and the main bearing axle boxes 11 for the rolls 13 is always eliminated.
In this way, the play between the housing 10 and the main bearing axle boxes 11 for the rolls 13 is eliminated by the operation of the full-time play eliminating cylinders 18 and 19; the play between the rolls 13 and the main bearings 12 is eliminated by the operation of the non-forming-time play eliminating cylinders 21; and the gap between the rolls 13 can be retained to the setting value ga with high accuracy. As a result, even if the material 1A is made of extremely very thin sheet metal, an accuracy required for the forming is acquired to enable the efficient manufacturing of the separators 1 (see
Moreover the roll shafts 13c of the rolls 13 are directly coupled to the separate servo motors 26 through the reduction gears 25 including their respective strain wave gearing mechanisms and the reduction gears 25 are directly coupled to the corresponding main bearing axle boxes 11. Thus, when the servo motors 26 are driven, the rotative powers of the servo motors 26 are transmitted through the shafts 26a to the reduction gears 25 including the strain wave gearing mechanisms, decelerated and transmitted to the roll shafts 13c of the rolls 13 and, as a result, the rolls 13 are independently rotated. Since the servo motors 26 have a lower value of speed variance of the order of ±0.01% and therefore have reduced vibrations and since the shafts 26a of the servo motors 26 are directly coupled to the reduction gears 25 including the strain wave gearing mechanisms and no play is generated by, for example, a backlash of a gear or a clearance of a joint, rotative forces with reduced vibration can be transmitted to the reduction gears 25 including the strain wave gearing mechanisms. Since the reduction gear 25 including the strain wave gearing mechanism is a reduction gear having an extremely minimal backlash and therefore the rotative force of the servo motor 26 is transmitted to the roll 13 with vibrations suppressed as much as possible, the roll 13 is stably rotated without vibrations.
Pattern control may be employed such that a longitudinal forming amount of the material 1A becomes constant while any different push-in amount in the forming area is allowed as a function of a different elastic deformation in the forming area due to different fitting of the arc-shaped die 14. For example, in the case of the die 14 fitted tightly to a flattened outer circumferential portion of the roll 13 as shown in
Thus, the material 1A made of sheet metal to be formed can be formed with high accuracy without deteriorated production efficiency and the separators 1 may be efficiently manufactured with high accuracy.
It is to be understood that a method and a device for manufacturing a separator for a polymer electrolyte fuel cell are not limited to the above embodiment and that various changes and modifications may be made without departing from the scope of the invention.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP09/07050 | 12/21/2009 | WO | 00 | 4/13/2012 |