Supercharged pressure control valve apparatus

Abstract: In a supercharged pressure control valve apparatus of an internal combustion engine, a housing (31) of supercharger has first and second by-pass air paths (34, 35); a valve sheet formed on an end of the second by-pass air path; a rubber diaphragm (38) having thick sealing part of convex and concave sectional shape at its outer periphery; a valve disc (40) fixed to the moving part of the diaphragm (38) and opening closing the first and the second by-pass air paths (34, 35) responding to movement of the diaphragm (38); and a casing (36) of the valve directly fixed on the housing (31) by sandwiching the outer periphery of the diaphragm (38).

Description: BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to a supercharger pressure control valve apparatus according to the preamble of claim 1, for regulating abnormal pressure rise in the upstream part of an air suction path of a throttle valve, which may occur at closing the throttle valve for deceleration. 2. DESCRIPTION OF THE PRIOR ART The EP-A-0 123 515 discloses a supercharger pressure control valve apparatus, comprising a housing having a pressure side air path and a suction side air path of a supercharger therein, a casing fixed on the housing, a diaphragm, the outer periphery of which is sandwiched between the casing and the housing, and a valve disc fixed to the diaphragm, circulation of supercharged air between said pressure side air path and suction side air path being permitted by movement of said diaphragm against a biasing spring. The said diaphragm comprises a sealing part having a convex section for closing the connection between said suction side air path and said pressure side air path by contacting with a valve seat of the housing arranged around said pressure side air path. The said valve seat and the mounting surface of the housing, on which the outer periphery of the diaphragm is mounted, are formed on different planes, i. e. at different levels. Therefore, the cost for making the known apparatus is relatively high; above all in view of the fact that the plane comprising the valve seat and the said mounting surface have to be made in a precise correlation to each other. Another conventional supercharger pressure control valve apparatus to be used in an internal combustion engine as, for example, shown in Published Unexamined Japanese Utility Model Application Hei 1-58723, will be described now with reference to FIG. 3. FIG. 3 is a cross-sectional view showing the said conventional supercharger pressure control valve apparatus. In FIG. 3, the conventional supercharger pressure control valve apparatus comprises: an air cleaner 1 serving as an air sucking portion; suction pipes 2 and 2 serving as paths of suction air from the air cleaner 1; a supercharger 3 connected to the suction pipes 2 and 2; a throttle valve 6 for controlling the amount of the suction air; a decompression path 8; and a supercharger pressure control valve 9. In the suction pipe 2, the upstream part 4 of the supercharger 3 is a first suction air path and the downstream part 5 of the supercharger 3 is a second suction air path. The decompression path 8 connects the first and second suction air paths 4 and 5. The supercharger pressure control valve 9 controls the pressure of the supercharged pressure in the second suction air path 5 by opening and closing the decompression path 8. Details of the supercharger pressure control valve 9 are described. The supercharger pressure control valve 9 comprises: a cylindrical housing 10; a second path formed in a wall part of the housing 10 for introducing the supercharged air in the second suction air path 5 to a second pressure chamber 29; and a flange 13 formed on the lower end of the housing 10 and mounted on a mounting part 14 of the suction pipe 2 serving as the second suction air path 5. Furthermore, a valve seat 15 is formed on an inner wall of the housing 10 and around an opening 13a of the flange 13. A nipple part 16 of the housing 10 serving as an inlet and an outlet of the suction air is connected to the suction pipe 2 serving as the first suction air path 4. A disc-shaped diaphragm 17 is sealed at its outer periphery by a cup-shaped casing 18 and circular periphery of top end of the housing 10. A first pressure chamber 1 is formed by the diaphragm 17 and the casing 18. A first path 20 connects an output port 21 and a nipple 22 for introducing the supercharged air in a third suction air path 7 to the first pressure chamber 19. Plate-shaped holders 23a and 23b sandwiches the center part of the diaphragm 17, and an end of a rod 24 is connected at the center of the holders 23a and 23b. The valve disc 25 for opening and closing the decompression path 8 is connected to the other end of the rod 24 and formed to contact with the valve seat 15. The rod 24 is slidably born by a bearing 26 and the bearing 26 is supported by a bearing holder 27. A spring 28 is compressedly provided between the casing 18 and the holder 23a for supplying an elastic force to the inside bottom of the diaphragm 17 in a direction to close the valve 9. The second pressure chamber 29 is formed between the diaphragm 17 and the bearing holder 27 and connected to the second suction air path 5 by the second path 11. A throttle 30 is formed in the second path 11 which serves as an air resistance for making a transfer lag of the pressure in the second path 11. In the above-mentioned conventional supercharger pressure control valve apparatus, a seal member 23c is necessary to keep the sealing of the casing 18 and the housing 10. Thereby, number of the parts and components for constituting the apparatus is great and the workability to assemble the casing 18 on the housing 10 is not good. Furthermore, the supercharger 3 and the supercharger pressure control valve 9 are independently disposed and connected by the suction pipe 2. As a result, a large space is necessary to provide the conventional apparatus. Still more, the conventional apparatus needs plural pipes for making the by-pass air path (decompression path 8) and thereby, the cost for making the conventional apparatus is expensive. SUMMARY OF THE INVENTION The purpose of the present invention is to provide an improved supercharger pressure control valve apparatus, in which the size thereof is made small and the cost for making the apparatus is reduced. The said object of the invention is achieved by the characterizing features of claim 1 in combination with the features of its preamble. Preferred embodiments and structural details of the present invention are described in the subsidiary claims, and with reference to the enclosed drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 is a cross-sectional side view showing preferred embodiment of a supercharged pressure control apparatus in accordance with the present invention. FIG.2 is a cross-sectional side view showing another preferred embodiment of a supercharge pressure control valve apparatus in accordance with the present invention. FIG.3 is a cross-sectional side view showing the constitution of the conventional supercharged pressure control valve apparatus. DESCRIPTION OF THE PREFERRED EMBODIMENTS A first preferred embodiment of a supercharger pressure control valve apparatus in accordance with the present invention is described referring to FIG.1. In FIG.1, the supercharger pressure control valve apparatus in accordance with the present invention comprises: a housing 101 of a supercharger having therein a first and a second by-pass air paths 103 and 104; a casing 105 fixed on the housing 101 by screws; a valve seat 108 formed at an end of the second by-pass air path 104; a valve disc 122 having a seal part 110 which has a convex section for closing the second by-pass air path 104 by contacting with the valve seat 108; a pipe-shaped holder 111 fixed on the valve disk 122 in the casing 105 for holding the valve disc 122; a pipe- shaped support 120 fixed on the ceiling of the casing 105 and outer surface thereof being slidably coupled with the inner surface of the holder 111 in a manner to make the valve disc 122 slidably move in vertical direction; a compression spring 113 provided between the support 120 and the holder 111; and a nipple 114 connected to a downstream part of a throttle valve which is provided in, for example, the first by-pass air path 103 in vertically lower position of the apparatus (not shown in the figure because of obvious). When the valve disk 122 is moved in upper direction against the elastic force of the spring 113, the first by-pass air path 103 and the second by-pass air path 104 are connected to be passed by an air current. A bottom hole 121 is formed on the bottom end of the support 120 and the top end of a center shaft 123 of the valve disc 122 has a wedge-shaped snap-fit part 123a. The shaft 123 loosely couples with the hole 121 of the support 120. A diaphragm 124 is integrated with the valve disc 122 by baking treatment. Outer periphery 124a of the diaphragm 124 is made thick and has convex and concave section and it is directly sandwiched by the casing 105 and the housing 101. In the above-mentioned supercharger pressure control valve apparatus, the outer periphery 124a of the diaphragm 124 seals the gap between the casing 105 and the housing 101, thereby the conventional seal member 23c shown in FIG.3 is not necessary. Furthermore, the shaft 123 of the valve disc 122 involves with the hook part 121 of the support 120. so that the seal part 110 of the diaphragm 124 may not fall out from the valve seat 108. Another preferred embodiment of the supercharger pressure control valve apparatus is described referring to FIG.2. In this embodiment, a supercharger pressure control valve apparatus is integrated in a supercharger. In FIG.2, a housing 31 of the supercharger has an air suction path 33 in which the sucked air passes, a first and a second by-pass ways 34 and 35. A fan 32 is rotatably born in a room 31a of the housing 31. In the supercharger pressure control valve apparatus, a casing 36 is fixed on the housing 31 by screw 37; a diaphragm 38 made of rubber has a thick convex and concave section at its outer periphery 38a, which is fixed by sandwiching between the casing 36 and the housing 31 for sealing a gap therebetween. A valve seat 39 is formed on an end of the second by-pass air path 35. The valve seat 39 and a mounting surface 31b of the housing 31, on which the diaphragm 38 is mounted, are formed on the same plane. A valve disc 40 made of resin is baked so as to be integrated with the diaphragm 38. A sealing part 41 of the valve disc 40 touches the valve seat 39 for closing the second by-pass air path 35. A spring 42 is provided between a support 43 and a holder 44 in the casing 36. A nipple 45 is formed on the upper part of the casing 36 connected to downstream part 34b of a throttle valve 6 which is provided, for example, in the first by-pass air path 34 for introducing the supercharged air in the first by-pass air path 34 to a pressure chamber 36a in the casing 36 by a path 20. Operations of the above-mentioned embodiment of the supercharger pressure control valve apparatus in accordance with the present invention is described. For medium load driving or heavy load driving of an automobile, the throttle valve 6 is substantially fully opened. Pressures in both of an air suction path on the downstream part 34b of the throttle valve 6 and the first by-pass air path 34 are highly pressed due to the supercharging effect of the fan 32 of the super-charger. The pressures in both sides of the diaphragm 38 are the same and positive pressures. As a result, a force in a direction to close the valve disc 40 by the spring 42 is applied to the diaphragm 38 and the valve disc 40 is completely closed by contacting of the sealing part 41 with the valve seat 39. When the state of the automobile engine is changed to the deceleration driving in which the throttle valve 6 is suddenly closed from the above-mentioned medium load driving or heavy load driving, the pressure in the downstream part 34b of air suction path of the throttle valve 6 is changed to a negative high pressure and that in the casing 36 also changes to a great negative high pressure. The pressure in the first by-pass air path 34 is raised to a high positive pressure so far as the fan 32 rotates. As a result, the valve disc 40 is opened against the force of the spring 42 and the supercharged air circulates in the first and second by-pass air paths 34 and 35. Therefore, undesirable abnormal pressure rise in the upstream part 34a of the throttle valve 6 is prevented. As mentioned above, in the supercharger pressure control valve apparatus in accordance with the present invention, the outer periphery of the diaphragm made of rubber and having thick convex and concave section 124 or 38 is directly sandwiched by the housing 101 or 31 and the casing 105 or 36. Hence the conventional sealing member is omitted, and the numbers of the parts constituting the apparatus is reduced and the workability to assemble the apparatus is improved. Furthermore, since the supercharger and the supercharger pressure control valve are integrated in one body, the conventional pipes for connecting the supercharger and the supercharger pressure control valve are not necessary any more. Thereby, the space necessary for the apparatus is to be provided decreases and the cost to make the apparatus is reduced. Still furthermore, since the part where the diaphragm 124 or 38 is fixed and the part of the valve seat 108 or 39 of the housing 101 or 31 are on the same plane, the cost to make the housing 101 or 31 low and the work to assemble the supercharger pressure control valve on the supercharger is easy.

Claims: A supercharger pressure control valve apparatus, comprising a housing (31, 101) having a pressure side air path (34, 103) and a suction side air path (35, 104) of a supercharger therein, a casing (36, 105) fixed on the housing (31, 101), a diaphragm (38, 124), the outer periphery (38a, 124a) of which is sandwiched between the casing (36, 105) and the housing (31, 101), and a valve disc (40, 122) fixed to the diaphragm (38, 124), circulation of supercharged air between said pressure side air path (34, 103) and suction side air path (35, 104) being permitted by movement of said diaphragm (38, 124) against a biasing spring (42, 113), characterized in that said valve disc (40, 122) comprises a sealing part (41, 110) which has a convex section for closing the connection between said suction side air path (35, 104) and said pressure side air path (34, 103) by contacting with a valve seat (39, 108) of the housing (31, 101) arranged around said suction side air path (35, 104), and said valve seat (39, 108) and the mounting surface (31b) of the housing (31, 101), on which the outer periphery (38a, 124a) of the diaphragm (38, 124) is mounted, are formed on the same plane. Apparatus according to claim 1, wherein said valve disc (40, 122) is integrated with said diaphragm (38, 124) by baking treatment. Apparatus according to claim 1 or 2, wherein a pipe-shaped holder (44, 111) is fixed on the valve disc (40, 122) in the casing (36, 105) for holding the valve disc (40, 122) while a pipe-shaped support (43, 120) is fixed on the ceiling of the casing (36, 105), the outer surface of said support (43, 120) being slidably coupled with the inner surface of said holder (44, 111) so as to make the valve disc (40, 122) slidably move in vertical direction. Apparatus according to claim 3, wherein said valve disc (40, 122) comprises a center shaft (123), the top end of which has a wedge-shaped snap-fit part (123a), loosely coupled with a bottom hole (121) formed on the bottom end of the support (120). Apparatus according to claim 1, wherein a fan (32) of the supercharger is rotatably contained in a room (31a) formed in the housing (31, 101). Apparatus according to claim 1, wherein the diaphragm (38, 124) is made of rubber, having a thick convex and concave section at the outer periphery (38a, 124a) thereof which is fixed by being sandwiched between the casing (36, 105) and the housing (31, 101) for sealing a gap therebetween.

Inventors: HAGITA ATSUSHI C O SAGAMIHARA, KYOYA MICHIO C O SAGAMIHARA MA, MIYOSHI SOTSUO C O SANDA SEISA, HAGITA, ATSUSHI, KYOYA, MICHIO, MIYOSHI, SOTSUO, HAGITA, ATSUSHI, C/O SAGAMIHARA MACHINERY, KYOYA, MICHIO, C/O SAGAMIHARA MACHINERY, MIYOSHI, SOTSUO, C/O SANDA SEISAKUSHO
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI HEAVY IND LTD, MITSUBISHI DENKI KABUSHIKI KAISHA, MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1990
Main classification: F02B37
IPC codes: F02B37