JP2007510098A - Pressure regulating valve with backflow prevention device - Google Patents

Abstract

  A pressure regulating valve (1) having a backflow prevention device installed in a fuel propulsion line (9) between a pump working chamber (21) and an injection nozzle (10) of a fuel injection pump of a compression ignition engine is a stepped type. The axial flow path (12; 12, 33, which is inserted in the pump working chamber side, further includes a valve box (2) having a pipe connection port shape having an axial flow hole portion (3). 34, 35, 36), a first valve seat (13) surrounding the axial passage is provided at the nozzle side end of the insertion device, and a gap is further provided. A fuel pressure on the pump chamber side, which has a valve plate having a portion (15) and acts to cause the first valve closing member (17) to elastically deform the tongue-shaped constricted portion (16) by the gap. Can be lifted from its sealing pedestal by means of a first valve closing member (1 ) And a formed throttle bore (19) in the.

Description

Detailed Description of the Invention

  The present invention relates to a pressure regulating valve provided with a backflow prevention device installed in a fuel propulsion line between a pump working chamber of a fuel injection pump of a compression ignition engine and an injection nozzle.

  In a known pressure regulating valve installed in the propulsion line between the pump working chamber and the injection nozzle, the valve closing member is lifted from the valve seat by the propulsive pressure of the fuel, so that the pressure regulating valve is adjusted to the pressure of the valve spring. It is opened in opposition and fuel can flow into the injection part. At the end of the high-pressure fuel supply, the valve closing member returns again to its sealing valve seat and at the same time the injection part is closed.

  What is important here is that pressure formation occurs on the injection nozzle at high speed and with as little delay as possible. Therefore, it is assumed that the volume for filling the fuel becomes as small as possible, and the delay time caused by the filling is made as short as possible. However, a hollow portion generated in the structure, that is, a so-called dead space cannot be avoided.

  Furthermore, shock waves can be caused by a sudden stop of the pressure fuel supply in the closed volume between the pressure regulating valve and the injection nozzle, which reciprocates between the pressure regulating valve and the injection nozzle. This type of shock wave can unnecessarily open the injection nozzle of the closed injection section, which can cause fuel to drip and form unwanted fuel residues.

  In order to prevent shock waves, it is known to provide a backflow prevention device that can flow in the direction opposite to the flow direction of the pressure regulating valve, so that in the pressure line after the pressure regulating valve is closed Can be reduced to a specific static pressure that can be set in advance.

  In the conventional system, this kind of backflow prevention device is arranged in an independent recess in the flow hole of the valve box of the pressure regulating valve. This backflow prevention device generally has a cartridge sleeve having a valve seat disposed in a recess and formed on an annular end surface on the nozzle side thereof, and a sealing surface acting together with the valve seat and an inner diameter of the cartridge sleeve. And a valve plate joined to the annular end surface of the cartridge sleeve on the nozzle side, and a backflow prevention device spring that presses the valve plate against its sealing base. In operation, the propelled fuel moves the valve plate toward the injection nozzle until it is lifted from its seat against the pressure of the backflow prevention spring and joined to the appropriate stopper surface, thereby fueling the fuel. Is formed without any obstacles. When the fuel propulsion is finished, the valve plate is again pressed against the sealing base by the spring pressure of the backflow prevention device spring, and the pressure in the propulsion line is given in advance by the spring pressure of the backflow prevention device spring through the throttle hole. Reduces to static pressure.

  The problem with the conventional backflow prevention device is that it is necessary to provide a sufficient space for arranging the backflow prevention device spring, and this becomes a dead space for rapid fuel supply to the injection section as described above. is there. In addition, since the valve plate violently collides with the stopper surface when the pump piston is suddenly operated, the conventional backflow prevention device is very easy to wear out. Furthermore, the conventional backflow prevention device is troublesome to remove.

  An object of the present invention is to overcome the problems of the pressure regulating valve provided with the above-described conventional backflow prevention device, reduce dead space, improve wear resistance, and easily remove the backflow prevention device. It is providing the pressure regulation valve provided with.

  The object is solved according to the invention by a pressure regulating valve according to claim 1. Preferred additional configurations are indicated by the features of the dependent claims.

  The pressure regulating valve provided with the backflow preventing device according to the present invention includes a valve box having a pipe connection port shape having a step-type axial flow hole portion, and the axial hole portion is in the direction of the pump working chamber. First, a hollow portion having a first hollow cylinder shape is formed by expansion and further connected thereto to form a hollow portion having a second hollow cylinder shape by expansion. Here, the hollow portion having the second hollow cylinder shape is formed. Has a larger cross-sectional diameter than the hollow portion of the first hollow cylinder shape. Therefore, the axial flow hole portion first forms the first hollow portion toward the pump working chamber, and is further connected to the enlarged second hollow portion to form the flow hole portion in a stepwise manner. Consists of three pieces connected to each other. In the enlarged portion from the flow hole portion to the first hollow portion, a step portion is formed by the nozzle-side canopy surface of the first hollow cylinder-shaped hollow portion formed by the gap of the connection portion of the flow hole portion. A first stopper surface having a shape is formed. In the enlarged portion from the first hollow portion to the second hollow portion of the flow hole portion, a step portion is formed by the nozzle side canopy surface of the second hollow cylinder-shaped hollow portion formed by the gap of the connection portion of the first hollow portion. This forms an annular second stopper surface.

  The pressure regulating valve according to the present invention further includes an insertion device inserted into the second hollow cylinder-shaped recess of the valve box on the pump working chamber side. This insertion device can be composed of a single part or a plurality of parts, and has an axial flow path. In addition, a first valve seat surrounding the axial passage is provided at the nozzle side end of the insertion device.

  Furthermore, the pressure regulating valve according to the present invention includes a valve plate that is pressed against the ring-shaped second stopper surface of the second recess by the nozzle side end of the insertion device. What is important here is that the valve plate has a gap portion, a tongue-shaped constriction portion that can be elastically deformed by the gap portion, and a first valve closing member coupled to the tongue-shaped constriction portion; Is formed. In other words, the gap defines the tongue-shaped constriction from the valve plate and the contour of the first valve closing member coupled thereto, thereby maintaining the connection between the tongue-shaped constriction and the other valve plate portion. Is done. The tongue-shaped constricted portion is dimensioned such that the elastic deformability of the tongue-shaped constricted portion or the valve closing member coupled thereto is maintained. In other words, the first valve closing member can be swung from the plane of the valve plate by the elastic deformability of the tongue-shaped constriction.

  In the present invention, the first valve closing member on the one hand shields the connection port of the axial passage of the insertion device, and on the other hand, on the extension in the axial direction, the annular second stopper surface of the second recess portion The first valve closure member can enter into the first recess by a pivoting movement which is dimensioned to be accommodated within it and thereby enabled by the elastic deformation of the tongue-shaped constriction. It is characterized by that. In addition, the first valve closure member includes a first sealing surface that works with the first valve seat of the plug-in device.

  The first valve closing member can be lifted from its sealing pedestal by pump chamber side fuel pressure which acts to cause elastic deformation of the tongue-shaped constriction, according to the present invention, wherein the first valve closing member is The valve closing member enters the first hollow portion of the valve box during the turning operation based on the tongue-shaped constricted portion. Further, the first valve closing member has a height in the axial direction of the first hollow portion having a hollow cylinder shape so that the first valve closing member is joined to the first stopper surface of the first hollow portion when the first valve closing member is sufficiently swung. Are set to dimensions.

  In order to function as a backflow prevention device, the first valve closing member is provided with a throttle hole formed in the axial extension of the connection port of the axial flow hole portion of the insertion device according to the present invention. In order to achieve the throttling effect, the diameter of the throttling hole is made smaller than the diameter of the connection port of the axial flow hole portion of the plug-in device.

  In a first preferred configuration of the pressure regulating valve according to the present invention, the plug-in device is configured as a tubular valve body having an axial through hole. Therefore, the pressure regulating valve is substantially constituted only by the pressure connection between the valve box and the valve body through the backflow prevention device press-fitted between the valve box and the valve body. In this configuration, the backflow prevention device has not only a throttling function for eliminating shock waves in the propulsion line, but also a substantial pressure regulating valve function, that is, a function for opening and closing the propulsion line according to the fuel pressure on the pump working chamber side. To achieve. This type of pressure regulating valve structure with a backflow prevention device, which is significantly simplified compared to a pressure regulation valve with a conventional backflow prevention device, greatly reduces dead space, This is because the expansion of the flow hole portion of the valve box only needs to be formed only in the first hollow portion and the second hollow portion except for the flow hole portion and the flow hole portion of the valve box.

  According to another preferred configuration of the pressure regulating valve provided with the backflow prevention device according to the present invention, the valve body having a through hole portion formed therein includes an annular surface that forms the second valve seat. ing. Furthermore, the pressure regulating valve includes a second valve closing member, which is axially opposed to the spring pressure of the valve spring disposed in the second recess of the valve box in the axial flow hole of the valve body. A second sealing surface is provided that is slidable in the direction and acts with the second valve seat of the valve body.

  In another preferred configuration of the pressure regulating valve provided with the backflow prevention device according to the present invention, the plug-in device is composed of a plurality of parts, and a tubular valve body having an axial flow hole portion; A cartridge sleeve joined to the nozzle side annular end surface of the valve element by the annular end surface on the pump working chamber side, and an inner sleeve joined to the nozzle side annular end surface of the cartridge sleeve by the annular end surface on the pump working chamber side. Here, the valve body forms a second valve seat by its nozzle-side annular surface. The pressure regulating valve further includes a second valve closing member, which counteracts the spring pressure of the valve spring disposed in the spring chamber in the second recess of the valve box in the axial flow hole of the valve body. And a second sealing surface that is slidably disposed in the axial direction and that works together with the second valve seat of the valve body.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of a pressure regulating valve equipped with a backflow prevention device according to the present invention, which has an insertion member composed of a single part. The pressure regulating valve 1 includes a pipe connection port-shaped valve box 2 having a step-type axial flow hole portion 3. The flow hole 3 is formed by expanding the first hollow cylinder-shaped recess 4 in the direction of the pump working chamber and then connecting it to the second hollow cylinder-shaped recess 5 by expanding. Forming. Here, the second hollow cylinder-shaped depression 5 has a larger cross-sectional diameter than the first hollow cylinder-shaped depression 4. The first hollow cylinder-shaped depression 4 is provided with a first stopper surface 6 that is annular toward the direction of the injection nozzle, while the second hollow cylinder-shaped depression 5 is annular toward the direction of the injection nozzle. A second stopper surface 7 is provided. The through hole 3 is connected to the conical opening 8 on the nozzle side in order to connect to a propulsion line 9 for supplying fuel to the injection unit 10.

  A valve body 11 made of a single component is inserted into the second hollow cylinder-shaped depression 5 of the valve box 2 on the pump working chamber side. The valve body 11 includes an axial flow path 12. A first valve seat 13 that surrounds the axial flow path 12 is provided at the nozzle side end of the valve body 11. The axial passage 12 of the valve body 11 is disposed on the axial extension of the flow hole portion 3 of the valve box 2. The valve box 2 and the valve body 11 are screwed together (not shown) according to a conventional method. The end of the valve body 11 on the pumping chamber side is fixed in a liquid-tight manner to the cylinder part 22 of the pump unit that forms the pumping chamber 21 using the sealing element 20.

  A valve plate 14 made of a steel plate is attached between the nozzle side end of the valve body 11 and the annular second stopper surface 7 of the second recess 5 (the upper right valve plate 14 in FIG. 1). (See the enlarged view). As shown in the enlarged view of the valve plate 14, the valve plate 14 includes an annular fragment-shaped gap portion 15. The gap portion 15 forms a tongue-shaped constricted portion 16 that can be elastically deformed, and a first valve closing member 17 that is coupled to the tongue-shaped constricted portion. The first valve closing member 17 on the one hand shields the opening 18 of the axial passage 12 of the valve body 11 and on the other hand on the extension in the axial direction, the annular second stopper of the second recess 5. It is dimensioned to be accommodated in the surface 7. In addition, the first valve closing member 17 includes a first sealing surface 18 that works together with the first valve seat 13 on the sealing side end surface of the valve body 11. The first valve closing member 17 can move out of the plane of the valve plate 14 by turning around the constricted portion 16 that is elastically deformable.

  The first valve closing member 17 has its sealing pedestal 13 formed by a swiveling operation based on the tongue-shaped constricted portion 16 by the fuel pressure on the pump chamber side that acts to cause elastic deformation of the tongue-shaped constricted portion 16. Here, the first valve closing member 17 enters the first recess 4 of the valve box 2 and reaches the junction of the first recess 4 with the first stopper surface 6. To do.

  Further, the first valve closing member 17 includes a throttle hole 19 in the axial extension of the opening 18 of the axial flow hole 12 of the valve body 11. In order to achieve the throttling effect, the diameter of the throttling hole 19 is made smaller than the diameter of the axial flow hole portion 12 of the valve body 11. For example, the throttle hole has a diameter of 0.5 to 1.0 mm. As shown in FIG. 1, the flow hole portion 3 of the valve box 2, the flow hole portion 12 of the valve body 11, and the throttle hole 19 of the valve closing member 17 are aligned coaxially with each other.

  The operation method of the pressure regulating valve according to the present invention shown in FIG. 1 is as follows. High pressure fuel propelled by the pump element lifts the first valve closing member 17 from its sealing pedestal 13 against the pressure of the tongue-shaped constriction acting against the elastic deformation, Thus, the first valve closing member 17 enters the first recess 4 of the valve box 2 and reaches the junction of the first recess 4 with the annular first stopper surface 6. Here, the fuel can flow from the pump working chamber 21 of the cylinder member 22 of the pump unit to the injection unit 10 without any obstacle. Due to the “overpressure” in the propulsion line for rapid propulsion, the first valve closing member 17 is pressed against the sealing base 13 with its sealing surface 18 to close the propulsion line to the injection part. A shock wave that may be generated between the first valve closing member 17 and the injection unit 10 is caused by a static pressure preset in the propulsion line by a pressure required for elastic deformation of the tongue-shaped throttle unit. It is attenuated through the throttle hole 19 until it is formed.

  FIG. 2 is a block diagram showing a preferred embodiment of a pressure regulating valve provided with a backflow prevention device according to the present invention provided with an insertion device composed of a plurality of parts. Components equivalent to those of the pressure regulating valve according to the present invention in FIG. 1 are denoted by the same reference numerals. In order to avoid unnecessary repetition, the embodiment of the pressure regulating valve according to the present invention shown in FIG. 2 will be described only with respect to a structure different from the pressure regulating valve of FIG.

  The plug-in device for the pressure regulating valve 1 in FIG. 2 includes a tube-shaped valve body 11 having an axial through-hole 12 and an annular end face 24 on the pump working chamber side. A cartridge sleeve 23 to be joined to the nozzle sleeve 25 and an inner sleeve 28 to be joined to the nozzle-side annular end face 27 of the cartridge sleeve 23 by the annular end face 26 on the pump working chamber side. Here, the inner sleeve 28 is provided with a flow hole 36. The valve body 11 forms a second valve seat 29 by the nozzle-side annular surface 25.

  The pressure regulating valve 1 further includes a second valve closing member 30, which is disposed in the spring chamber 35 in the second recess 5 of the valve box 2 in the axial flow hole 12 of the valve body 11. The valve spring 31 is arranged so as to be slidable in the axial direction against the spring pressure. The second valve closing member 30 further includes a second sealing surface 32 that works together with the second valve seat 29 of the valve body 11. A groove 33 is provided on the peripheral surface of the second valve closing member 30 to couple the second recess 5 with the flow hole 12 of the valve body 11, which is the second sealing. It is connected to an annular groove 34 arranged on the upstream side of the surface 32. The valve box 2 and the valve body 11 are screwed together (not shown) according to a conventional method, where the cartridge sleeve 23, the inner sleeve 28, and the valve plate 14 are pressed against each other. The axial flow path of the insertion device of the embodiment shown in FIG. 2 is constituted by the flow hole portion 12, the groove portion 33, the annular groove portion 34, the spring chamber 35, and the flow hole portion 36 of the inner sleeve. Has been.

  The operation method of the pressure regulating valve according to the present invention shown in FIG. 2 is as follows. The second valve closing member 30 is lifted from its sealing pedestal 29 against the pressure of the valve spring 31 by the high pressure fuel propelled by the pump element, and the pressure regulating valve 1 shifts from its closed state to its open state, The annular groove 34 is connected to the spring chamber 35 of the valve spring 31. The high pressure fuel further lifts the first valve closing member 17 from its sealing pedestal 13 against the pressure of the tongue-shaped constriction 16 acting in the opposite direction against the elastic deformation, where the first The valve closing member 17 enters the first recess 4 of the valve box 2 and reaches the junction of the first recess 4 with the annular first stopper surface 6. Here, the fuel can flow from the pump working chamber 21 of the cylinder member 22 of the pump unit to the injection unit 10 without any obstacle. Due to the rapid propulsion, the second valve closing member 30 is pressed against the sealing base 29 by the spring pressure of the valve spring 31, and the pressure regulating valve shifts from the open state to the closed state. At the same time, the first valve closing member 17 is pressed onto the sealing pedestal 13 with its sealing surface 18 by “overpressure” in the propulsion line. A shock wave that may be generated between the first valve closing member 17 and the injection unit 10 is formed in the propulsion line by a static pressure set by a pressure necessary for elastic deformation of the tongue-shaped throttle unit. It is attenuated through the throttle hole 19 until it is done.

It is the block diagram which showed the suitable Example of this invention provided with the insertion apparatus which consists of a single component. It is the block diagram which showed the suitable Example of this invention provided with the insertion apparatus which consists of multiple components.

Claims (8)

A pressure regulating valve (1) comprising a backflow prevention device installed in a fuel propelling line (9) between a pump working chamber (21) of a fuel injection pump of a compression ignition engine and an injection nozzle (10);
A pipe connection valve-shaped valve box (2) with a stepped axial flow hole (3), said axial hole (3) facing the direction of the pumping chamber (21); First, the first hollow cylinder-shaped depression (4) is formed by expansion, and further connected to the depression (4) to form the second hollow cylinder-shaped depression (5) by expansion. This second hollow cylinder shaped depression (5) has a larger cross-sectional diameter than the first hollow cylinder shaped depression (4), where the first hollow cylinder shaped depression (4) is An annular first stopper surface (6) is provided in the direction of the injection nozzle, while the second hollow cylinder-shaped recess (5) is annular in the direction of the injection nozzle. )
-Having an axial flow passage (12; 12, 33, 34, 35, 36) inserted on the pumping chamber side in the second hollow cylinder-shaped recess (5) of the valve box (2) A first valve seat (13) that includes an insertion device and surrounds the axial flow path is provided at the nozzle side end of the insertion device,
A valve plate (14), which is pressed against the annular second stopper surface (7) of the second recess (5) by the nozzle side end of the plug-in device, this valve plate (14) Includes a tongue-shaped constricted portion (16) having a gap portion (15) and elastically deformable by the gap portion, and a first valve closing member (17) coupled to the tongue-shaped constricted portion. The first valve closing member (17) is formed and shields the connection port (18) of the axial passage (12; 12, 33, 34, 35, 36) of the plug-in device and extends in the axial direction. Comprising a first sealing surface (18) which is arranged to be accommodated in a ring-shaped second stopper surface (7) above and which acts together with the first valve seat (13) of the plug-in device, The first valve closing member (17) acts to cause elastic deformation of the tongue-shaped constriction (16). The fuel pressure on the pump chamber side can be lifted from the sealing pedestal so that the first valve closing member (17) enters the first recess (4) of the valve box (2) and enters the first recess (4). Reaching the first stopper surface (6) of the depression (4) of 1;
A throttle formed on the axial extension of the connection port (18) of the axial passage (12; 12, 33, 34, 35, 36) of the plug-in device in the first valve closing member (17) Provided with a hole (19), the throttle hole having a smaller diameter than the connection port (18) of the axial passage (12; 12, 33, 34, 35, 36) of the plug-in device,
Pressure regulating valve.   2. The pressure regulating valve according to claim 1, wherein the valve plate (14) has a flat plate shape.   The pressure regulating valve according to claim 1 or 2, characterized in that the gap (15) is formed in a fragmentary ring shape.   The pressure regulating valve according to any one of claims 1 to 3, wherein the valve plate (14) is formed of a steel plate.   5. A pressure regulating valve according to claim 1, wherein the throttle hole (19) has a diameter in the range of 0.5 to 1.0 mm.   The pressure regulating valve according to any one of claims 1 to 5, wherein the plug-in device comprises a tubular valve body (11) having an axial flow hole (12).   The valve body (11) is provided with an annular surface forming a second valve seat, and the pressure regulating valve is provided with a second valve closing member, which is formed in the valve body in the axial flow hole. A second sealing surface is provided that is slidable in the axial direction against the spring pressure of the valve spring disposed in the second recess, and that acts together with the second valve seat of the valve body. The pressure regulating valve according to claim 6.   The insertion device is joined to the nozzle-side annular end surface (25) of the valve body by the tubular-shaped valve body (11) having an axial flow hole (12) and the annular end surface (24) on the pump working chamber side. And an inner sleeve (28) joined to the nozzle-side annular end surface (27) of the cartridge sleeve (23) by the annular end surface (26) on the pump working chamber side. (11) forms a second valve seat (29) by the nozzle-side annular surface (25), and the pressure regulating valve (1) further includes a second valve closing member (30), which is a valve body. The spring pressure of the valve spring (31) disposed in the spring chamber (35) in the second recess (5) of the valve box (2) in the axial flow hole (12) of (11). It is arranged so as to be slidable in the axial direction against the valve element (11). The pressure regulating valve according to any one of 5 claims 1 comprising a second sealing surface (32) acting together with the second valve seat (29).

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