Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C49/06—Injection blow-moulding
  • B29C49/061—Injection blow-moulding with parison holding means displaceable between injection and blow stations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/58—Blowing means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D22/00—Producing hollow articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C2049/023—Combined blow-moulding and manufacture of the preform or the parison using inherent heat of the preform, i.e. 1 step blow moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2949/00—Indexing scheme relating to blow-moulding
  • B29C2949/07—Preforms or parisons characterised by their configuration
  • B29C2949/0715—Preforms or parisons characterised by their configuration the preform having one end closed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C49/06—Injection blow-moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2031/00—Other particular articles
  • B29L2031/703—Bellows

Definitions

• the subject of the invention is a method and an apparatus for manufacturing a protective bellows for a transmission device, such as a constant velocity joint or the like, and the bellows obtained by implementing this method.
• the problem is therefore to provide a method of manufacturing a protective bellows of complex structure, of the type of those currently used as protective bellows of transmission mechanisms, such as constant velocity joints, which can be implemented. with the materials desired for this type of protection bellows, while allowing industrial production at an acceptable cost price.
• a method of manufacturing by injection-blowing of a thermoplastic material is implemented, according to which a bellows blank is first injected into a first mold and during a first phase. and the ends thereof and in that, according to the invention, the procedure is carried out in a second mold with core and shells defining the turns of the bellows and which provides at least a pinching zone between the core and the shells at the junction of at least two adjacent turns, to a blowing of the blank turn by turn or by group of turns during a second phase and until the desired shape of the bellows is obtained.
• Such a method makes it possible to give the ends the desired shape and thickness, since they are injection molded, and to give the turns the desired profile by blowing the blank on the wall of the shells which form said second mold.
• the method is implemented by applying a single thermoregulated mobile core, as a constitutive element of the first and said second mold.
• the first mold comprising the thermoregulated core
• the thermoregulated core is associated with shells, - advantageously two half-shells, the temperature of which is chosen to freeze the thermoplastic material used during contact between the latter and the shells.
• Such an embodiment is particularly advantageous in that it allows, during the closing of the second mold, that is to say during the application of the demicoqui on the blank carried by the core-, to conform the blank- che the right of nips in a predefined form ⁇ completed, by a procedure analogous to molding by "cold emprein ⁇ te" of the hot thermoplastic material.
• Apparatus for manufacturing a protective bellows for transmission device by implementing the method as described above then comprises a first shell mold and thermoregulated core for the formation by injection on said core of a blank of the bellows.
• a second mold comprising said core and shells the temperature of which is chosen to freeze the thermoplastic material used during contact between the latter and the shells, the latter being conformed to their walls internal facing next to the bellows to be manufactured, on the one hand and, on the other hand, according to imprints of shape and dimension such that they provide with the core, in the condition of closing of said second mold, at least a pinching zone of the blank at the junction of at least two adjacent turns by limiting the blowing chambers of each turn or of groups of turns, the core being pierced with circulating channels blowing ires opening into said chambers, with means of adjustment independently or not from each other of the flow rates, temperatures, and blowing pressures in each of said chambers.
• said second mold is with two half-shells which are shaped such that the closing of said mold causes the total or almost total cutting of the disc of material formed at one of the longitudinal ends of the blank at during the injection process.
• the separation of this disc of material from the ends of the blank to which they are adjacent then makes a subsequent cutting operation unnecessary with the consequence that there is no recovery on an auxiliary machine and, consequently, a saving of time and productivity important.
• the blowing means associated with the thermoregulated core are organized to allow the blowing of hot air, such an arrangement also contributing to obtaining satisfactory results, both with regard to the regularity of the 'thickness of the turns as the shape thereof, by conser ⁇ vation of the plastic nature of the material used during this blowing of hot air.
• FIG. 1 to 6 are schematic views illustrating the different phases of the process according to the invention.
• FIG. 7 is a schematic view partly in section and partly in elevation of the second mold, or blowing mold, of an apparatus according to the invention for the fabrication of a bellows for protecting the hokinetic joint?
• FIG. 8 is a partial view, on a larger scale, of part of such a bellows, part of a half-shell and a core constituting said second mold blowing.
• Said mold 10 comprises two half-shells 11 and 12, respectively, and a central core 13 somewhat frustoconical in the application described herein of a protective bellows gasket homociné ⁇ tick.
• the injection of thermoplastic material is carried out in line with the joint plane, as shown in 14, and in an apparatus of which the core and the half shells are hot, at a temperature compatible with that of the thermoplastic material used.
• the core 13 is lined with the blank E ( Figure 2) and the half-shells 11, 12 are then moved away from the core which they release ( Figure 3).
• the core 13 lined with the blank E which retains its state of plasticity due to the thermoregulation of the core 13-, is brought by a handling device, not shown, for example a carousel , inside a second mold, or blow mold with two half-shells 15 and 16 (FIG. 4), initially spaced apart from each other and which then close around the core 13.
• a handling device not shown, for example a carousel
• the blank is caused to blow using one or more streams of fluid, as shown schematically by the arrow S of the figure 5, the draft is pressed against the internal wall of each half-shell 15 and 16 and then takes the desired shape.
• the half-shells 15 and 16 are then separated from one another (FIG. 6), the opening of the mold allowing the extraction of the core 13 and then of the bellows thus produced by injection-blowing.
• a core 20, of revolution comprising at one of its ends a part 21 with an external surface 22, which continues, towards its other end front materialized by a face 23, by an external surface with corrugations like 25, 26, 27 etc., the last of which, 29, is connected to the face 23 by a substantially cylindrical external surface 30 in which can be arranged grooves like 31 and 32.
• the core 20, as clearly visible in FIG. 7, houses circular channels • • suitable for being connected to one or more sources of pressurized fluids, not shown, and which opens (s) onto the external face of said core, which is provided with means, not shown, for regulating its temperature. Means, also not shown, make it possible to adjust the flow rate, the temperature and the pressure of the blowing fluid in each channel 40 independently or not of the temperature, the flow rate and the pressure in the other channels.
• the half-shells 11 and 12 associated with the core 20 to form the injection mold are of the usual type for obtaining on said core a blank of souf ⁇ flet E, as shown in dotted lines in the figure 7, the invention provides a particular embodiment of the two half-shells, one of which is shown at 60, and which, associated with the core 20, form the second mold or blow mold. Said half-shells are shaped on their internal wall 61 according to the external surface which it is desired to give to the protective bellows and each thus has adjacent hollows 62,, 62-, 62, etc.
• each half-shell has a bearing surface 63, 64, respectively, the latter continuing with a face 65 perpendicular to the axis A As well shown, also, in FIG.
• the two half-shells 60 are each shaped, at least in certain junction zones of at least two adjacent recesses, according to imprints 66 whose shape corres ⁇ pond very exactly to that which one wishes to give to the bellows in the corresponding zones, for example in the embodiment described and represented, along a straight section with sides 67 and 68 inclined and connected to their apex by a U-shaped rib with edges 69, 70, parallel and bottom 71 slightly curved.
• the half-shells are maintained at a temperature chosen to freeze the thermoplastic material used during their contact with them, as explained below, and they are shaped and dimensioned with respect to to the core 20 so that in the operating condition of the second mold or blowing mold, which is that shown in FIG. 7, the core housed inside the two half-shells 60 limits therewith a first zone d end between the bearing surface 63 and the surface 22, a second end zone between the port 64 and the surface 30 and a space between the face 65 and the face 23, respectively. Between the two end zones, the half-shells 60 and the core 20 are very close to one another in pinch zones, such as 35, 36, 37, etc., thus defining chambers, each of which is limited.
• boreholes like 76 on which are connected in der vation canals like 77 ,, 77-, 77 ,, etc .. which open at their other end into the recesses 62, substantially tops of these.
• These channels and boreholes are provided for if necessary, to cause a partial vacuum in each or some of the chambers limited by the internal surface of the shells and the facing surface of the core 20, the degree of vacuum being able to be different from a room to another.
• the closing of the blowing mold on the blank E has the consequence that, on the one hand, the imprints like 66 of the half-shells at a temperature chosen to freeze the thermoplastic material used during their contact with them, shape the blank E in a similar manner to a molding in the space between the cavities and the core 20, thus giving the relevant zones of the bellows the exact desired shape and, on the other hand, causing the material constituting the blank to be pinched in line with these cavities, with the result the sealed separation with respect to each other of the chambers limited by said imprints and the facing surfaces of the core and the shells.
• thermo ⁇ plastic material is further improved, with the consequence -l'obt obtain, directly from blowing, parts with the desired shapes, as shown in solid lines on Figure 7. Les ⁇ said parts, which are further shaped, at least in certain areas of junction of the turns that is to say in the areas with the highest concentration of stresses during operation, to the exact shape required are then cut to remove the disc like 78 formed during the injection of the thermoplastic material constituting the fluff at one end of it.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
• Diaphragms And Bellows (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9347800

Family Applications (1)

Country Status (6)

Families Citing this family (3)

Family Cites Families (6)

• 1987
  • 1987-02-11 FR FR8701699A patent/FR2610566B1/fr not_active Expired
• 1988
  • 1988-02-01 WO PCT/FR1988/000052 patent/WO1988006088A1/fr not_active Application Discontinuation
  • 1988-02-01 DE DE198888901425T patent/DE303638T1/de active Pending
  • 1988-02-01 EP EP88901425A patent/EP0303638A1/fr not_active Withdrawn
  • 1988-02-01 JP JP63501479A patent/JPH01502893A/ja active Pending
  • 1988-02-11 ES ES8800383A patent/ES2006559A6/es not_active Expired

Non-Patent Citations (1)

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