JP2010174870A5 - - Google Patents

Description

Further, the gas passage groove 42 becomes larger as the distance between the pair of side walls facing each other, that is, the outer wall of the central cylindrical portion 17b and the inner wall of the intermediate cylindrical portion 17c, becomes closer to the gas passage cover 18 side. The LPG fuel pressure reducing valve is mounted on the vehicle in a posture in which the axis of the valve mechanism 15 is horizontal, as shown in FIG.

By the way, the gas passage cover 18 is fitted into the outer peripheral ring portion 17a and a ring-shaped outer peripheral flat plate portion 18a in which an annular seal member 45 is interposed between one surface of the outer peripheral ring portion 17a of the body 17. The outer cylindrical portion 18b whose one end is connected to the inner peripheral edge of the outer peripheral flat plate portion 18a, and the ring whose outer periphery is connected to the other end of the outer cylindrical portion 18b so as to be in close proximity to the first annular connecting plate portion 17d of the body 17. Jo an intermediate flat plate portion 18c of the inner cylindrical portion 18d which allowed to fit one end of the central cylindrical portion 17b of the body 17 causes Ren'nara at one end to the inner periphery of the intermediate plate portion 18c, one end of the central cylindrical portion 17 b And a disc-shaped central flat plate portion 18e connected to the other end of the inner cylindrical portion 18d so as to face each other with a gap therebetween.

A decompression chamber 48 communicating with the valve hole 24 is formed between the central flat plate portion 18 e of the gas passage cover 18 and the central cylindrical portion 17 b of the body 17. The decompression chamber 48 is communicated with the gas passage 43. A notch 50 for forming a communication passage 49 for the gas passage cover 18 and the central cylindrical portion 17b is provided on the outer periphery of one end portion of the central cylindrical portion 17b. That starting point PS of the gas passage 43 is an opening end of the gas passage 43 of the communication passage 49.

The first retainer 83 is provided integrally with the diaphragm rod 85. The diaphragm rod 85 has a bottomed cylindrical portion 85a having a shape in which one end is closed and the other end on the valve mechanism 15 side is opened, and the first projecting outward from the one end closed portion of the bottomed cylindrical portion 85a in the radial direction. The retainer 83 and the shaft portion 85b coaxially connected to the center of the closed end portion of the bottomed cylindrical portion 85a are integrally provided. The shaft portion 85b having a smaller diameter than the bottomed cylindrical portion 85a is formed by the diaphragm 16. It is inserted through a central hole 87 provided at the center .

Moreover the first heating means 60, the engine cooling water heated fluid passage 6 1 so as to surround the valve chamber 30 provided in the valve housing 21 is a heating fluid, which are configured to flow, a circular cross It is possible to effectively heat the inner peripheral wall surface of the valve chamber 30 and to further increase the efficiency of heat transfer to the gas in the valve chamber 30. Also, the heating fluid passage 61, so provided from the opposite side to the valve seat 25 in the valve housing 21 has a portion surrounding the valve chamber 30, even more heat transfer efficiency to the LPG fuel in the valve chamber 30 Can be increased.

The gas passage 43 formed in the valve housing 21 is bent into a labyrinth by a plurality of fins 40, 41, etc. provided in the body 17 of the valve housing 21, but constitutes a part of the gas passage 43. In this way, the two wall surfaces facing each other, that is, the outer surface of the central cylindrical portion 17b and the inner surface of the intermediate cylindrical portion 17c in the body 17, are directed to the main flow direction 44 of the LPG fuel from the start point PS to the end point PE of the gas passage 43. The plurality of fins 40, 41,... Are arranged so as to be alternately arranged in the main flow direction 44 while being inclined so as to be directed upstream, so that the gas passage 43 is formed in a maze shape. fins 40 is bent ..., 41 ... of the length of the longer to the full fin 40 ..., it becomes possible to widen the 41 ... heat radiating area, circulation through the LPG fuel in the gas passage 43 That enables to lengthen, it is possible to further enhance the heat transfer efficiency to the LPG fuel. Moreover the full fin 40 ..., 41 ... is, since those directed to the upstream side with respect to the main flow direction 44 of the LPG fuel from the starting point PS of the gas passage 43 to the end point PE, the specific gravity of the LPG fuel high The liquid component is easily trapped at the base ends of the fins 40, 41, and it is possible to preferentially heat the liquid component and prevent the LPG fuel from being in a gas-liquid mixed state.

The outer peripheral edge of the diaphragm 16 connected to the valve shaft portion 34 b of the valve mechanism 15 is sandwiched between a diaphragm flange 77, which is a separate member from the valve housing 21, and a diaphragm cover 78 coupled to the outer periphery of the diaphragm flange 77. Since the electric heater 68 is arranged between the diaphragm flange 77 and the valve housing 21 in the axial direction of the valve mechanism 15, the pressure receiving area of the diaphragm 16 is reduced so that the change in the control pressure with respect to the change in the flow rate of the LPG fuel is reduced. In order to increase the pressure regulation performance, the electric heater 68 is arranged between the valve housing 21 and the diaphragm flange 77 so as to overlap the diaphragm flange 77. The diaphragm flange 77 is arranged in the valve housing 21. By using a separate member from the electric heater 68 Attachment to the valve housing 21 is facilitated.

Therefore, there are few restrictions at the time of the assembly of a pressure-reducing valve, design freedom can be increased, and productivity can be improved. That is, the workability is improved by connecting the diaphragm 16 and the diaphragm rod 85 independently of the valve shaft portion 34 b, and the work of holding the peripheral edge of the diaphragm 16 between the diaphragm cover 78 and the diaphragm flange 77 also has space restrictions. The pressure reducing valve can be reduced in size because it is possible to perform the operation without any need to secure a useless space for the tool arrangement on the body 17 side. In addition, the body assembly 100 and the diaphragm assembly 96 are individually functionally tested by performing an airtight inspection of the valve mechanism 15 on the body assembly 100 side and an airtight inspection of the diaphragm 16 on the diaphragm assembly 96 side. It is possible to improve reliability, and it is easy to check the assembled state of each part. Furthermore, by preparing different types of diaphragm assemblies 96 by changing the spring constants of the springs 81 and 82 in the diaphragm assembly 96 or by making the areas of the diaphragms 16 different, the body assembly 100 is shared. Thus, a plurality of types of pressure reducing valves having different control pressures can be manufactured.

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