Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
  • F16H55/32—Friction members
  • F16H55/36—Pulleys
  • F16H55/48—Pulleys manufactured exclusively or in part of non-metallic material, e.g. plastics
• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/0025—Preventing defects on the moulded article, e.g. weld lines, shrinkage marks
• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/0046—Details relating to the filling pattern or flow paths or flow characteristics of moulding material in the mould cavity
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F37/00—Details specific to washing machines covered by groups D06F21/00 - D06F25/00
  • D06F37/02—Rotary receptacles, e.g. drums
  • D06F37/04—Rotary receptacles, e.g. drums adapted for rotation or oscillation about a horizontal or inclined axis
• • 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
  • B29L2031/32—Wheels, pinions, pulleys, castors or rollers, Rims
  • B29L2031/322—Wheels, pinions, pulleys, castors or rollers, Rims made wholly of plastics
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
  • F16H55/02—Toothed members; Worms
  • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
  • F16H2055/065—Moulded gears, e.g. inserts therefor

Definitions

• the present invention refers to an improved manufacturing method for producing a pulley of plastic material, as well as to a pulley produced using this method, as intended in particular for use in drive systems provided in clothes washing machines to rotatably drive the drum thereof.
• Pulleys used in such kind of applications are generally known to be usually made of some aluminium-based metal alloy, in view of ensuring the necessary properties in terms of mechanical strength, chemical and heat resistance that such pulleys are required to possess in order to withstand the corresponding stresses, which they usually undergo under normal operating conditions.
• the US patent publication No. 5,931,755 describes a pulley, which is particularly suitable for use in motor-vehicles and is made of such thermoplastic materials as PPS (polyphenylsulfide), generally reinforced with glass fibres.
• PPS polyphenylsulfide
• the method used to mould the pulley calls for the plastic material to be injected through a single central runner, without therefore ensuring any certain, reliable and even distribution of the injected material.
• a pulley is fully and readily recyclable, without any need for it to be submitted to any preliminary operation to separate dissimilar materials.
• the pulley according to the present invention must be such as to allow for the greatest possible flexibility in producing pulleys of different models, types and size, so as to reduce production times and the related costs.
• FIG. 1 is an overall, perspective view of a pulley according to the present invention
• FIG. 2 is a cross-sectional view of the pulley shown in Figure 1 , as viewed along the axis A-A;
• FIG. 3 is a partially cross-sectional, schematic view of the injection mould used to produce the pulley shown in Figure 1;
• FIG. 4 is an enlarged view of the central portion of the injection mould shown in Figure 3.
• a pulley 10, as produced with the method according to the present invention and illustrated in Figures 1 and 2, is provided with a central hub 12 that is in turn provided with a hole 14 for press-fitting onto a rotatably driving shaft (not shown).
• the hub 12 is connected by a plurality of radially extending spokes 16 to a peripheral crown or rim 18, around which a driving belt or similar strap (not shown) is capable of being wrapped.
• the pulley 10 is produced by injection moulding using a plastic material reinforced with glass fibres.
• the preferred plastic material in this application is an engineering-type thermoplastic material, such as polypropylene, polyamide, or the like, which is filled with glass fibres to a percentage ranging from 40% to 70%, and has a modulus of elasticity of at least 15,000 MPa and a surface hardness of at least 100 R.
• a basic feature of the structure of the pulley according to the present invention is represented by the fact that the kind of material used to produce it enables a pulley to be obtained that is entirely and solely made of plastic material, i.e. is free of any metal insert or other metal element that might be used - in particular in the hub portion - in view of enhancing the strength thereof.
• This feature is further accompanied by a number of other advantageous properties, such as a high resistance to heat (200-300 J/m 2 ), an excellent shape and dimensional stability and, above all, full recyclability.
• pulley according to the present invention is suitable for use in a number of industry sectors, such as for instance the motor industry and the appliance industry.
• a pulley of this kind is found to be quite suitable for application in drive systems used to rotatably drive the drum of clothes washing machines.
• the newly devised method calls for the molten plastic material to be injected into the mould through a hot runner 20 in the moving part 22 of the same mould and a plurality of nozzles 24 arranged close to the central hub 12 of the pulley ( Figures 3 and 4), so that the joining or welding spots of the plastic material are caused to occur and lie along the peripheral rim of the pulley at the melting temperature of the same plastic material, i.e. approx. 250 0 C.
• the joining spots of the plastic material come to lie along the peripheral rim 18 of the pulleys at points that are located in an intermediate position between the end portions of the spokes 16 joining with the same rim.
• the moulding method according to the present invention calls for the use of a dual press with multiple-cavity interchangeable moulds, preferably two moulds provided with four cavities each. These moulds should be interchangeable in view of allowing for a maximum extent of production flexibility regardless of the different sizes and shapes of the pulleys to be moulded.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Pulleys (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=36294574

Family Applications (1)

Country Status (3)

Families Citing this family (8)

Family Cites Families (8)

• 2005
  • 2005-01-14 IT ITPN20050003 patent/ITPN20050003A1/it unknown
• 2006
  • 2006-01-10 EP EP06841248A patent/EP1874518A1/de not_active Withdrawn
  • 2006-01-10 WO PCT/EP2006/050115 patent/WO2007057234A1/en active Application Filing

Non-Patent Citations (1)

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