Patent Publication Number: US-2005132743-A1

Title: Collector for an air-conditioning unit for vehicles

Description:
The present invention refers to an improved collector for an air-conditioning unit for vehicles.  
      An air-conditioning unit for vehicles comprises, amongst other things, a condenser, a drying means for removing water particles from the cooling liquid and a filtering element for holding impurities possibly present in the cooling liquid.  
      As an alternative to the arrangement of a separate dehydrating filter, arranged in the air-conditioning unit between the condenser and the expansion valve, it has become common to integrate a drying means and a filtering element directly into a collector pipe of the condenser.  
      The condenser provided with an integrated dehydrating filter therefore has the task of removing water particles from the cooling liquid, filtering impurities possibly present in the cooling liquid and acting as an accumulator for a certain amount of liquid.  
      The drying means and the filtering element, for example contained in a rigid or semi-rigid casing that can be made from various materials and can be of various types, must generally be replaced after a certain operating period of the air-conditioning unit.  
      Alternatively, the drying means could be contained in permeable bags structurally separate from the filtering element. Also in this case it is suitable for the individual components to be able to be replaced by accessing inside the collector.  
      The collector pipe is thus provided at a cylindrical end thereof with a removable cap to allow access to the internal components. The removable cap can possibly be connected through suitable means to a cartridge containing the drying means.  
      Threaded caps made from aluminium or light alloy, as well as cylindrical caps equipped with at least one seat for the insertion of an O-ring that forms a seal against the wall of the collector pipe are commonly used. This second type of cap is generally made from aluminium alloy or else from moulded plastic material.  
      Known cylindrical caps are generally held in position by stop elements, or elastic safety rings, for example Seeger rings, positioned on the top of the caps themselves, which engage and form a seal in an annular seat or groove made on to inner wall of the collector pipe. The main drawback of this solution consists of the mechanical weakening of the whole circumference of the pipe caused by making the annular seat.  
      So as to be able to carry out the required processing, the thickness of the wall of the pipe, moreover, cannot be less than certain values that substantially restrict the minimum amount of material necessary for the production of the collector pipe.  
      The purpose of the present invention is that of making an improved collector for an air-conditioning unit for vehicles with reduced thickness and good mechanical strength.  
      Another purpose of the present invention is that of making an improved collector for an air-conditioning unit for vehicles that simplifies the mechanical processing with respect to current processing, as well as the assembly operations.  
      Another purpose of the present invention is that of making an improved collector for an air-conditioning unit for vehicles that is particularly simple and functional with low costs.  
      These and other purposes, according to the present invention, are accomplished by making an improved collector for an air-conditioning unit for vehicles as outlined in claim  1 .  
      Further characteristics are foreseen in the dependent claims. 
    
    
      Further characteristics and advantages of an improved collector for an air-conditioning unit for vehicles, according to the present invention, shall become clearer from the following description, given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:  
       FIG. 1  is a plan view of an improved collector for an air-conditioning unit for vehicles according to the present invention;  
       FIG. 2  is a section view according to the line II-II of  FIG. 1  of the collector according to the present invention partially split;  
       FIG. 3  is a partially interrupted top side view of the collector pipe of  FIG. 1 ;  
       FIG. 4  is a cross section carried out according to the line IV-IV of the collector of  FIG. 3 ;  
       FIG. 5  is a perspective view of a further embodiment of a cylindrical pipe for an improved collector according to the present invention. 
    
    
      With reference to FIGS.  1  to  4 , a first embodiment of an improved collector for an air-conditioning unit for vehicles is shown, wholly indicated with reference numeral  10 .  
      The collector  10  comprises a hollow cylinder  11  provided at one end with an opening  11 A for the insertion of a filtering and drying means (not shown).  
      The opening  11 A is suitable for receiving a substantially cylindrical cap  100 , which, when inserted axially into such an opening  11 A and secured in position by a stop element  20 , closes the collector pipe  11  sealed when it is put under pressure.  
      The cap  100 , in a preferred embodiment shown in section as a non-limiting example in  FIG. 2 , comprises many elements moulded in plastic material and stably coupled with each other.  
      The coupled elements form a succession of cylindrical portions with substantially the same diameter as the internal diameter of the pipe  11  and seats  15  with a smaller diameter for housing elastic sealing rings  14 , for example O-rings, as shown in  FIG. 2 .  
      In the cap  100 , for example, a first element  12  comprises a portion with the same diameter as the pipe  11  and two portions with a smaller diameter, as well as fastening means for a second element  13  and for a third element  16  arranged on opposite sides.  
      The first element  12 , in the preferred embodiment shown, is made equipped with an inner recess  32  diametrically divided by transversal walls  33 , one of which projects at one end of the cap  100  to form a gripping fin  34 . The fin  34  is perforated close to the upper end to ease the removal of the cap  100  from the pipe  11 .  
      The coupleable moulded elements  12 ,  13  and  16 , which in the examples shown are stably coupled through pressure fastening means, or clamps, can also be ultrasound electrowelded, without it being necessary to foresee the possibility of disassembly of the assembled cap.  
      Moreover, as an example, the cap  100  shown in  FIG. 2  comprises a spacer shaft  30  made integrally with it and able to be coupled with a cartridge integrated in the collector  100  (not shown, suitable for containing a drying means and a filtering means for the cooling liquid circulating in the collector pipe itself.  
      The collector pipe  10  is provided, in the portion adjacent to the insertion opening  11 A, with two opposite slits or slots  21 . The slits  21  are elongated and lie on the same diametric plane. The slits  21  are made as through holes that cross the entire thickness of the wall of the pipe  11 .  
      The slits or slots  21 , moreover, in further embodiments that are not shown, could also be in a number other than two, still arranged on a common diametric plane of the pipe  11 .  
      The stop element  20  is an elastic safety ring comprising a C-shaped body  22  equipped with two wings  23  projecting outwards in a position diametrically opposite and coplanar to the body  22 . The wings  23 , which in further embodiments that are not shown could be in a number other than two, are always of a shape matching the slits  21  of the cylindrical pipe  11  and in a position corresponding to them.  
      The elastic safety ring  20 , moreover, comprises a plurality of inner secondary wings  24  also coplanar to the body  22  and projecting radially inwards.  
      The stop element  20  equipped with inner wings  24  advantageously has a larger resting surface on the cap  100  with respect to the ring provided with just outer wings  23  (not shown), whilst still keeping a central body  22  that is sufficiently thin so that the ring  20  can be deformed, in other words stretched and then spread out, during the installation operations on the cap  100  inside the cylindrical pipe  11 .  
      The safety ring  20  is mounted in the pipe  11  on the top of the cap  100  inserting the outer wings  23  inside the slits  21 .  
      When the collector  10  in operation is put under pressure the cap  100  is held in axial position by the stop element  20  that forms a seal on the two wings  23  inside the slits or slots  21 .  
      The cylindrical pipe  11  according to the present invention can be made with reduced thickness, without any processing of an annular groove inside the pipe being necessary.  
      The cylindrical pipe  11  with reduced thickness according to the present invention can be subjected to critical values in terms of concentration of mechanical stresses at the ends of the slits or slots  21 .  
      To improve this critical situation, a further embodiment shown in  FIG. 5  foresees that the pipe  11 ′ be equipped on the outer surface with reinforcement elements  25  arranged in a tangent position to the edges of the holes  21 . The reinforcement elements are localised thickenings of the wall of the pipe  11  that, in a preferred embodiment, are made as longitudinal reinforcement ribs  25 . Such ribs  25 , which can advantageously be made in the extrusion step of the pipe  11 ′, extend for the entire length of said pipe  11 ′.  
      The cylindrical pipe of the improved collector for an air-conditioning unit for vehicles can advantageously be made with reduced thickness without penalising its mechanical characteristics. This means a significant reduction in weight of the aluminium used with a consequent substantial economic advantage.  
      Moreover, the assembly operations of the cap inside the cylindrical pipe are advantageously made easier in the collector according to the present invention. Indeed, it is possible to check the correct positioning of the safety ring directly from the slits made in the wall of the pipe.  
      The collector pipe according to the present invention can, moreover, advantageously be used with known closing caps of standardised size.  
      The improved collector pipe for an air-conditioning unit for vehicles thus conceived is susceptible to numerous modifications and variants, which are all covered by the invention itself; moreover, all of the details can be replaced with technically equivalent elements. In practice, the materials used, as well as their sizes, can be whatever according to the technical requirements.