Pressure reducing valve for gas
A pressure reducing valve for gas is provided in which a valve mechanism having opening in a central part a valve hole that communicates with a low pressure passage and a low pressure chamber and including a valve body that is capable of being seated on a valve seat facing a valve chamber communicating with a high pressure passage is housed within a body such that the valve body is connected to a pressure receiving member operating in response to pressure of the low pressure passage and the low pressure chamber, wherein the body ( 16 ) is formed by joining a plurality of body members ( 18, 19 ) having different strengths, the entirety of the high pressure passage ( 30, 64 ) being formed, among the plurality of body members ( 18, 19 ), within the body member ( 18 ) that has a high strength, and at least part of the low pressure passage ( 85, 86, 94, 119 ) and the low pressure chamber ( 83, 84, 116 ) being formed, among the plurality of body members ( 18, 19 ), within the body member ( 19 ) that has a low strength. This enables the cost to be reduced.
1. A pressure reducing valve for gas in which a valve mechanism ( 20 ) having opening in a central part thereof a valve hole ( 68 ) that communicates with a low pressure passage ( 85 , 86 , 94 , 119 ) and a low pressure chamber ( 83 , 84 , 116 ) and comprising a valve body ( 59 ) that is capable of being seated on a valve seat ( 58 ) facing a valve chamber ( 66 ) communicating with a high pressure passage ( 27 , 28 , 30 , 64 ) is housed within a body ( 16 , 16 ′) such that the valve body ( 59 ) is connected to a pressure receiving member ( 115 ) operating in response to pressure of the low pressure passage ( 85 , 86 , 94 , 119 ) and the low pressure chamber ( 83 , 84 , 116 ), characterized in that the body ( 16 , 16 ′) is formed by joining two, that is, first and second body members ( 18 , 19 ; 18 ′, 19 ′) having different strengths, the body ( 16 , 16 ′) being formed by joining the second body member ( 19 , 19 ′), which has a low strength, and the first body member ( 18 , 18 ′), which has a high strength and has an insertion hole ( 25 ) coaxially housing the valve mechanism ( 20 ), so that the second body member ( 19 , 19 ′) and the first body member ( 18 , 18 ′) overlap each other in a direction along an axis of the valve body ( 59 ) while forming therebetween a pressure reduction chamber ( 83 ), which is the low pressure chamber, and a circular cross-section fitting projection ( 18 a ) projectingly provided integrally with the first body member ( 18 , 18 ′) so as to be coaxial with the insertion hole ( 25 ) is hermetically fitted into the second body member ( 19 , 19 ′).
2. The pressure reducing valve for gas according to claim 1 , wherein a groove ( 110 , 133 , 134 ) is provided in at least one of joining faces of the plurality of body members ( 18 , 19 ; 18 ′, 19 ′) that are joined to each other to form the body ( 16 , 16 ′), the groove ( 110 , 133 , 134 ) forming between the body members ( 18 , 19 ; 18 ′, 19 ′) that are joined to each other a housing chamber ( 132 ) housing heating means ( 131 ) or a heating medium passage ( 109 ) through which a heating medium flows.
3. A pressure reducing valve for gas in which a valve mechanism ( 20 ) having opening in a central part thereof a valve hole ( 68 ) that communicates with a low pressure passage ( 85 , 86 , 94 , 119 ) and a low pressure chamber ( 83 , 84 , 116 ) and comprising a valve body ( 59 ) that is capable of being seated on a valve seat ( 58 ) facing a valve chamber ( 66 ) communicating with a high pressure passage ( 27 , 28 , 30 , 64 ) is housed within a body ( 16 , 16 ′) such that the valve body ( 59 ) is connected to a diaphragm ( 115 ) operating in response to pressure of the low pressure passage ( 85 , 86 , 94 , 119 ) and the low pressure chamber ( 83 , 84 , 116 ),
[1] characterized in that the body ( 16 , 16 ′) is formed by joining two, that is, first and second body members ( 18 , 19 ; 18 ′, 19 ′), a groove ( 110 , 133 , 134 ) is provided in at least one of joining faces of the body members ( 18 , 19 ; 18 ′, 19 ′), the groove ( 110 , 133 , 134 ) forming between the body members ( 18 , 19 ; 18 ′, 19 ′) in a state of being joined together a housing chamber ( 132 ) for housing heating means ( 131 ) or a heating medium passage ( 109 ) through which a heating medium flows, the first body member ( 18 , 18 ′) has an insertion hole ( 25 ) coaxially housing the valve mechanism ( 20 ), a circular cross-section fitting projection ( 18 a ) projectingly provided integrally with the first body member ( 18 , 18 ′) so as to be coaxial with the insertion hole ( 25 ) is hermetically fitted into a fitting hole ( 80 ) of the second body member ( 19 , 19 ′), the second body member ( 19 , 19 ′) clamps a peripheral edge part of the diaphragm ( 115 ) between the second body member ( 19 , 19 ′) and a diaphragm cover ( 17 ) so that the diaphragm ( 115 ) is positioned coaxially with the fitting hole ( 80 ), and the valve body ( 59 ) is connected to a central part of the diaphragm ( 115 ).
4. The pressure reducing valve for gas according to claim 3 , wherein the heating medium passage ( 109 ) or the housing chamber ( 132 ) is formed in an arc shape surrounding the valve body ( 59 ) and the valve seat ( 58 ) when viewed in a direction along an axis of the valve body ( 59 ).
5. The pressure reducing valve for gas according to claim 3 or 4 , wherein the heating medium passage ( 109 ) or the housing chamber ( 132 ) is disposed at substantially the same position as the valve seat ( 58 ) in a direction along an axis of the valve body ( 59 ).
6. The pressure reducing valve for gas according to claim 3 , wherein the body member ( 19 ; 18 ′, 19 ′) having the groove ( 110 , 133 , 134 ) formed therein is molded, and the groove ( 110 , 133 , 134 ) is formed at the same time as said molding.
7. The pressure reducing valve for gas according claim 3 , wherein a heating medium that is guided to the heating medium passage ( 109 ) is engine cooling water.
8. The pressure reducing valve for gas according to claim 3 , wherein the heating means ( 131 ) is an electric heater.