Flexible connection tube for automotive exhaust system

A flexible connection tube for an automatic exhaust system comprising:

• a flexible bellows adapted to be connected between a series of exhaust pipes and being flexible in both directions of expansion and contraction for absorbing expansion or contraction of said exhaust pipes;
• and
• an outer knitted metal wire braid covering an outer periphery of said bellows for protecting said bellows from damage and for preventing said bellows from stretching to its full length,
• wherein said outer knitted metal wire braid comprises a plurality of metal-wire bundles, each having a plurality of metal wires connected parallel to each other and in contact with each other with respect to a lateral direction of said metal wires, and wherein said outer knitted metal wire braid has a substantially cylindrical shape, formed by knitting said plurality of metal-wire bundles alternately with each other in spiral directions with respect to an axial direction of said bellows so that each of said metal-wire bundles extends along the outer periphery of said bellows in its spiral direction over both ends of said bellows,
• wherein said outer knitted metal wire braid has a plurality of apertures defined by groups of four adjacent metal-wire bundles knitted alternately with each other,
• wherein a total opening area of all of said apertures is set within a range of 20% to 50% with respect to an over-all area of a curved surface of said outer knitted metal wire braid, to provide a substantially cylindrical low-density knitted outer metal wire braid, and
• wherein said bellows is a flexible metal bellows having 15 or less ridges and a thickness equivalent to a spring constant having an elongation of 10 mm or less under a tensile load of 14 kgf or less.

A flexible connection tube for an automatic exhaust system comprising:

• a flexible bellows adapted to be connected between a series of exhaust pipes and being flexible in both directions of expansion and contraction for absorbing expansion or contraction of said exhaust pipes;
• an inner heat-damage protective pipe disposed in said bellows for protecting said bellows from heat damage;
• and
• an outer knitted metal wire braid covering an outer periphery of said bellows for protecting said bellows from damage and for preventing said bellows from stretching to its full length,
• wherein said outer knitted metal wire braid comprises a plurality of metal-wire bundles, each having a plurality of metal wires connected parallel to each other and in contact with each other with respect to a lateral direction of said metal wires, and wherein said outer knitted metal wire braid has a substantially cylindrical shape, formed by knitting said plurality of metal-wire bundles alternately with each other in spiral directions with respect to an axial direction of said bellows so that each of said metal-wire bundles extends along the outer periphery of said bellows in its spiral direction over both ends of said bellows,
• wherein said outer knitted metal wire braid has a plurality of apertures defined by groups of four adjacent metal-wire bundles knitted alternately with each other,
• wherein a total opening area of all of said apertures is set within a range of 20% to 50% with respect to an over-all area of a curved surface of said outer knitted metal wire braid, to provide a substantially cylindrical low-density knitted outer metal wire braid, and
• wherein said bellows comprises a pair of substantially cylindrical female tube-like portions at its both ends and said heat-damage protective pipe comprises two opposing, axially extending, diametrically diminished exhaust-pipe ends, respectively inserted into said female tube-like portions.

A flexible connection tube for an automatic exhaust system comprising:

• a flexible bellows adapted to be connected between a series of exhaust pipes and being flexible in both directions of expansion and contraction for absorbing expansion or contraction of said exhaust pipes;
• and
• an outer knitted metal wire braid covering an outer periphery of said bellows for protecting said bellows from damage and for preventing said bellows from stretching to its full length,
• wherein said outer knitted metal wire braid comprises a plurality of metal-wire bundles, each having a plurality of metal wires connected parallel to each other and in contact with each other with respect to a lateral direction of said metal wires, and wherein said outer knitted metal wire braid has a substantially cylindrical shape, formed by knitting said plurality of metal-wire bundles alternately with each other in spiral directions with respect to an axial direction of said bellows so that each of said metal-wire bundles extends along the outer periphery of said bellows in its spiral direction over both ends of said bellows,
• wherein said outer knitted metal wire braid has a plurality of apertures defined by groups of four adjacent metal-wire bundles knitted alternately with each other,
• wherein a total opening area of all of said apertures is set within a range of 20% to 50% with respect to an over-all area of a curved surface of said outer knitted metal wire braid, to provide a substantially cylindrical low-density knitted outer metal wire braid, and
• wherein at least one of a wire diameter of each of said metal wires, the number of said metal-wire bundles constructing said substantially cylindrical low-density knitted outer metal wire braid, and the number of said metal wires constructing each of said metal-wire bundles is reduced for setting said total opening area of said apertures within said range of 20% to 50% with respect to said over-all area of the curved surface of said outer knitted metal wire braid.

A flexible stainless steel connection tube for an automotive exhaust system comprising:

• a flexible austenitic-stainless-steel bellows adapted to be connected between a run of exhaust piping and being flexible in both directions of expansion and contraction for absorbing expansion or contraction of said exhaust piping;
• and
• an outer knitted stainless-steel-wire braid covering an outer periphery of said bellows for protecting said bellows from damage and for preventing said bellows from stretching to its full length,
• wherein said outer knitted stainless-steel-wire braid comprises a plurality of stainless-steel-wire bundles, each having a plurality of similar stainless steel wires connected parallel to each other and in contact with each other with respect to a lateral direction of said stainless steel wires, and wherein said outer knitted stainless-steel-wire braid has a substantially cylindrical shape, formed by knitting said plurality of stainless-steel-wire bundles alternately with each other in spiral directions with respect to an axial direction of said bellows so that each of said stainless-steel-wire bundles extends along the outer periphery of said bellows in its spiral direction over both ends of said bellows,
• wherein said outer knitted stainless-steel-wire braid has a plurality of apertures defined by groups of four adjacent stainless-steel-wire bundles knitted alternately with each other, and
• wherein a total opening area of all of said apertures is set within a range of 20% to 50% with respect to an over-all area of a curved surface of said outer knitted stainless-steel-wire braid, to provide a substantially cylindrical low-density knitted outer stainless-steel-wire braid.