Heater pipe

Abstract

A heater pipe ( 1 ) comprises an inner pipe ( 10 ) causing the engine cooling fluid to flow into a heater and an outer pipe ( 11 ) arranged on the outer peripheral side of the inner pipe ( 10 ) for causing the engine cooling fluid having heated the air-conditioning air in the heater to flow out from the heater. A joint ( 2 b ) includes an internal peripheral chamber ( 20 ), an outer peripheral chamber ( 21 ) arranged on the outer peripheral side of the inner peripheral chamber ( 20 ), a first branch joint portion ( 22 ) communicating with the inner peripheral chamber ( 20 ), and a second branch joint portion ( 23 ) communicating with the outer peripheral chamber ( 21 ) and arranged independently of the first branch joint portion ( 22 ). The heater pipe ( 1 ) and the joint ( 2 b ) are connected to each other by one action by engaging a pipe-side engaging portion ( 14 ) and a joint-side engaging portion ( 260 ) each other.

1 . A heater pipe interposed between an engine and a heater for circulating the engine cooling fluid through the heater, comprising: 
 an inner pipe for causing said engine cooling fluid to flow into said heater; and    an outer pipe arranged on the outer periphery of said inner pipe for causing the engine cooling fluid having heated the air-conditioning air in said heater to flow out of said heater.    
     
     
         2 . A heater pipe according to  claim 1 , 
 wherein said inner pipe and said outer pipe are arranged substantially coaxially.    
     
     
         3 . A heater pipe according to  claim 1 , comprising a plurality of joints each including the inner peripheral chamber of said inner pipe, the outer peripheral chamber of said outer pipe arranged on the outer periphery of said inner peripheral chamber, a first branch joint portion communicating with said inner peripheral chamber, and a second branch joint portion communicating with said outer peripheral chamber and arranged independently of said first branch joint portion.  
     
     
         4 . A heater pipe according to  claim 3 , 
 wherein said inner peripheral chamber and said first branch joint portion are arranged substantially linearly, and    wherein said outer peripheral chamber and said second branch joint portion are arranged with an intersection angle of more than 90 degrees between the axial lines thereof.    
     
     
         5 . A heater pipe according to  claim 3 , 
 wherein said first branch joint portion and said second branch joint portion are arranged substantially in parallel to the axial direction of the joints.    
     
     
         6 . A heater pipe comprising: 
 a pipe unit including an inner pipe causing the engine cooling fluid to flow into a heater, and an outer pipe causing the engine cooling fluid, having heated the air-conditioning air in said heater, to flow out of said heater;    a joint unit including an inner peripheral chamber connected to said inner pipe, an outer peripheral chamber arranged on the outer periphery of said inner peripheral chamber and connected to said outer pipe, a first branch joint portion communicating with said inner peripheral chamber, and a second branch joint portion communicating with said outer peripheral chamber and arranged independently of said first branch joint portion; and    an inner peripheral seal unit arranged between said inner pipe and said inner peripheral chamber; and    an outer peripheral seal unit arranged between said outer pipe and said outer peripheral chamber;    wherein said pipe unit includes a pipe-side engaging portion, and said joint unit includes a joint-side engaging portion, so that said pipe unit and said joint unit are connected to each other by one action by engaging said pipe-side engaging portion and said joint-side engaging portion each other.    
     
     
         7 . A heater pipe according to  claim 6 , 
 wherein said inner peripheral chamber and said outer peripheral chamber are partitioned by a partitioning wall integrated with said joint unit.    
     
     
         8 . A heater pipe according to  claim 6 , 
 wherein said inner peripheral chamber and said outer peripheral chamber are partitioned by said inner pipe.    
     
     
         9 . A heater pipe according to  claim 6 , 
 wherein at least one of said inner peripheral seal unit and said outer peripheral seal unit is arranged in such a position as not to reduce the cross sectional area of the flow path of said engine cooling fluid.    
     
     
         10 . A heater pipe according to  claim 6 , 
 wherein at least one of said inner peripheral seal unit and said outer peripheral seal unit is held in an axial direction between said pipe unit and said joint unit by the engaging force of said pipe-side engaging portion and said joint-side engaging portion.    
     
     
         11 . A heater pipe according to  claim 6 , 
 wherein said joint-side engaging portion is formed integrally with said joint unit.    
     
     
         12 . A heater pipe according to  claim 6 , 
 wherein said joint-side engaging portion and said pipe-side engaging portion are arranged in such a position as to suppress the reduction in the sealing force of said outer peripheral seal unit which otherwise might occur due to the engagement of said joint-side engaging portion and said pipe-side engaging portion.    
     
     
         13 . A heater pipe according to  claim 6 , 
 wherein said joint-side engaging portion is an engaging hook arranged on the outer peripheral surface of the outer wall surrounding said outer peripheral chamber,    wherein said pipe-side engaging portion is an annular rib arranged around the outer peripheral surface of said outer pipe, and    wherein said pipe unit and said joint unit are connected to each other by one touch with said engaging hook engaging said annular rib.    
     
     
         14 . A heater pipe according to  claim 6 , 
 wherein at least one of the members making up the connecting portion between said outer pipe and said outer peripheral chamber and the connecting portion between said inner pipe and said inner peripheral chamber has a tapered portion to facilitate the positioning of the heater pipe and the joint at the time of connection thereof.