JP2010116891A - Flow limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow limiter capable of reducing manufacturing cost in the flow limiter, without requiring to adjust press-in force without requiring work caused by the occurrence of these by eliminating generation of shavings and burrs by being installed in a casing without pressing in a stopper, and without requiring to manufacture the stopper by a conventional high strength (high hardness) construction material by reducing pressure received to a valve by arranging a pressure damping orifice between the valve and an injection port (an outflow port). <P>SOLUTION: This flow limiter has the casing 2, an inflow port 3, the outflow port 4, a space 5, the valve 6, a valve seat 7, an elastic member 8 and the stopper 10. The stopper 10 is a cylindrical elastic member having elastic force outward in the radial direction, and is installed on the inflow port side of the casing 2 by the elastic force. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow limiter that is provided in a fuel injection device and prevents an excessive amount of fuel from flowing from a common rail that stores high-pressure fuel to an injector corresponding to each cylinder of an internal combustion engine.

Conventionally, various flow limiters are known.
JP 2004-027966 A

  FIG. 4 shows an example of a conventional flow limiter. As shown in FIG. 4, the flow limiter 50 is provided on the upstream side of the injector, and stops the fuel flow when the fuel amount (pressure) exceeds a predetermined value. The interior includes an inlet 52, an outlet 53, a space 54, a valve 55, a valve seat 56, a compression coil spring 57, a stopper 59, and the like. The stopper 59 is press-fitted into the casing 51, and a communication path 58 that connects the inflow port 52 and the space 54 is formed. In the communication path 58, a pressure attenuation orifice 61 that reduces the area of the path is formed. ing.

  When fuel from a common rail (not shown) flows into the inflow port 52, the fuel enters the space 54 through the communication path 58, and the valve 55 is resisted against the pressing force of the compression coil spring 57 and the valve seat 56. It moves to the side, passes through the hollow portion 60 formed in the valve 55 and the communication port 65, flows out of the outlet 53 through the space 54, and flows into the injector (not shown).

  When the fuel from the common rail does not flow into the inflow port 52 or almost does not flow, the rear end portion 62 of the valve 55 is in contact with the stopper 59 by the pressing force of the compression coil spring 57. That is, a reflected wave (pressure wave) propagating from the injector side to the common rail side by the water hammer generated when the injector is closed acts on the valve 55, and the valve 55 moves to the stopper 59 side. At this time, the pressure attenuating orifice 61 attenuates the reflected wave (pressure wave), so that the pressure variation in the common rail is prevented.

  On the other hand, when the amount (pressure) of fuel from the common rail flowing into the inflow port 52 exceeds a predetermined value, the tip 63 of the valve 55 is engaged with the valve seat 56, and the injector is excessively charged. The amount of fuel is prevented from flowing.

  However, the conventional flow limiter described above has the following problems. That is, since the stopper 59 in which the communication path 58 is formed is press-fitted and attached to the casing 51, the press-fitted inner surface of the casing 51 is shaved during the press-fitting process of the stop pad 59, and shavings and burrs are generated. There was a problem to do. Further, since the stopper 59 is held in the casing 51 by press-fitting, there is a problem that this holding force (pressure input) must be managed (if a burr occurs, correction for correcting the pressure input value, etc.). was there. Further, when the characteristics of the flow limiter into which the stopper 59 is press-fitted are not good, there is a problem that the flow limiter has to be discarded. As a result, the flow limiter has a high manufacturing cost.

  Further, as described above, since the pressure damping orifice 61 is formed in the communication path 58 of the stopper 59, the valve 55 receives a large pressure propagating from the injector side to the common rail side. There is a problem that a high surface pressure is generated in the stopper 59 that comes into contact. Therefore, the stopper 59 has to be manufactured with a material having high strength (high hardness), and there is a problem that the manufacturing cost is increased.

  The present invention has been made in view of the above-described problems of the prior art, and by attaching the stopper to the casing without press-fitting, work resulting from these occurrences can be eliminated without generating shavings or burrs. No need to adjust the pressure input, and the pressure damping orifice is placed between the valve and the injection port (outlet) to reduce the pressure received by the valve, and the stopper is It is an object of the present invention to provide a flow limiter that does not require manufacturing with a material having a high strength (high hardness) and that can reduce the manufacturing cost of the flow limiter.

  The present invention provides a casing, an inflow port through which a predetermined substance flows into the casing, an outflow port through which the material that has flowed in from the inflow port flows out, and the inflow port and the outflow port to communicate with each other. A space formed in the casing; a valve slidably provided in the space; a valve seat formed on the outlet side of the space to allow the valve to be seated; and provided in the space. And an elastic member that presses the valve to the inlet side, and a stopper that is provided on the inlet side of the casing and has an inflow side communication passage that communicates the inlet and the space. In the limiter, the stopper is a cylindrical elastic member having an elastic force radially outward, and is attached to the inlet side of the casing by the elastic force. To provide a Rimitta.

  The stopper can be detachably attached to the casing. Further, it is preferable that the stopper is attached in a state in which one end face of the stopper protrudes from the inlet side end face of the casing when the flow limiter is assembled.

  For example, the stopper is wound in a cylindrical shape, and a convex portion is formed at one end portion, and a concave portion that engages with the convex portion and receives the convex portion is formed at the other end portion. When pressed, the cylindrical compression spring can be made to return to the original shape by the elastic force radially outward against the pressing force.

  Further, a pressure damping orifice is formed between the valve slidably provided in the space and the outlet, and the pressure damping orifice is, for example, the outlet side of the space. It is possible to form an outflow side communication passage that communicates the space formed between the valve seat formed at the outlet and the outlet and the outlet.

  According to the first aspect of the present invention, the casing, the inflow port for allowing a predetermined substance to flow into the casing, the outflow port for discharging the material that has flowed in from the inflow port to the outside, the inflow port and the outflow port. A space formed in the casing so as to communicate with each other, a valve slidably provided in the space, and a valve seat formed on the outlet side of the space, on which the valve can be seated. And a stopper having an elastic member that is provided in the space and presses the valve toward the inlet side, and an inflow side communication passage that is provided on the inlet side of the casing and communicates the inlet and the space. The stopper is a cylindrical elastic member having an elastic force radially outward, and is attached to the inlet side of the casing by the elastic force. Therefore, it is not necessary to attach the stopper to the casing by press-fitting as in the past, and as a result, there is no need for work caused by these occurrences by eliminating the shavings and burrs caused by press-fitting and adjusting the pressure input. Therefore, the manufacturing cost of the flow limiter can be reduced.

  According to the invention of claim 2, since the stopper is detachably attached to the casing, the flow limiter is not discarded even if the characteristics of the flow limiter are not good. In addition, it is possible to remove the stopper and replace the parts, thereby reducing the manufacturing cost of the flow limiter.

  According to the third aspect of the present invention, the stopper is attached in a state where one end surface of the stopper protrudes from the end surface on the inlet side of the casing when the flow limiter is assembled. The end surface can be completely in contact with the common rail body, and the flow limiter can be reliably set to a predetermined height (position) with respect to the common rail body.

  According to a fourth aspect of the present invention, the stopper is wound in a cylindrical shape, a convex portion is formed at one end portion, and a concave portion that engages with the convex portion and receives the convex portion at the other end portion. When it is formed and pressed inward in the radial direction, it is a cylindrical compression spring that attempts to return to its original shape by elastic force outward in the radial direction against this pressing force. , It is unnecessary to attach the stopper to the casing by press-fitting, and as a result, there is no need to adjust the pressure input by eliminating the occurrence of shavings and burrs due to press-fitting and the work resulting from these occurrences. The manufacturing cost of the flow limiter can be reduced.

  According to the fifth aspect of the present invention, since the pressure damping orifice is formed between the valve slidably provided in the space and the outlet, the pressure received by the valve is reduced. Thus, it is unnecessary to manufacture the stopper with a material having a high strength (high hardness) as in the prior art, and the manufacturing cost of the flow limiter can be reduced.

  According to the sixth aspect of the present invention, an outflow side communication passage that connects the space and the outflow port is formed between the valve seat formed on the outflow side of the space and the outflow port. Since the pressure damping orifice is formed in the outflow side communication passage, the pressure received by the valve is reduced and the stopper is made to have a high strength (high strength) as in the prior art. It is not necessary to manufacture with a material having a hardness, and the manufacturing cost of the flow limiter can be reduced.

  Hereinafter, the best mode for carrying out the flow limiter according to the present invention will be described with reference to the drawings. As is well known, the flow limiter according to the present invention is used in a fuel injection system (not shown) for an internal combustion engine. This fuel injection system for an internal combustion engine includes a flow limiter, a fuel tank, a high-pressure fuel supply device, It is mainly composed of a common rail, injectors, switches and sensors, an electronic control unit (ECU), and the like.

  The high-pressure fuel supply device increases the pressure of the fuel pumped from the fuel tank and supplies it to the common rail. The common rail stores the high-pressure fuel supplied from the high-pressure fuel supply device and corresponds to each cylinder of the internal combustion engine via the injection pipe. Each injector is configured to inject high pressure fuel into the fuel chamber of the internal combustion engine at a predetermined timing. The ECU determines target values such as the fuel injection amount and the injection timing based on feedback information such as the accelerator opening, the engine speed, the pressure in the common rail, etc. detected by the switches and sensors. A control signal is output.

  The flow limiter 1 is for preventing an excessive amount of fuel from flowing from the common rail to the injector corresponding to each cylinder of the internal combustion engine. FIG. 1 shows a cross-sectional view of a flow limiter according to the present invention. As shown in FIG. 1, the flow limiter 1 has one end attached to a predetermined position of the common rail body, a casing 2 formed in a hollow shape, and fuel (predetermined substance) in the common rail in the casing 2. An inflow port 3 for inflow, an outflow port 4 for flowing out fuel (substance) flowing into the casing 2 to the injector side (outside), and the inflow port 3 and the outflow port 4 are formed in the casing 2 so as to communicate with each other. A space 5, a valve 6 slidably provided in the space 5, a valve seat 7 formed on the outlet 4 side of the space 5 to allow the valve 6 to be seated, and the space 5. A compression coil spring 8 as an elastic member that presses the valve 6 toward the inlet 3, and a stopper 10 that is provided on the inlet 3 side of the casing 2 and has an inlet communication passage 9 that communicates the inlet 3 with the space 5. And mainly Eteiru.

  The valve 6 is formed in a shape in which a front end portion 11 can be fitted to the valve seat 7, and an opening portion 13 is formed in the rear end portion 12. In addition, a hollow portion 14 having one end side communicating with the opening portion 13 and the other end side extending to the vicinity of the tip portion 11 is formed in the intermediate portion of the valve 6. A communication port 15 for communicating the hollow portion 14 and the space 5 is formed.

  The stopper 10 is for restricting the movement range of the valve 6 provided in the casing 2 in the valve opening direction. The stopper 10 is a cylindrical elastic member having an elastic force outward in the radial direction, and is detachably attached to the inlet 3 side of the casing 2 by this elastic force. For example, as shown in FIG. 2, the stopper 10 is wound in a cylindrical shape, and a convex portion 10 a is formed on one end side thereof, and the convex portion 10 a is engaged with the other end side of the stopper 10. A concave portion 10b for receiving 10a is formed, and when pressed inward in the radial direction, a cylindrical compression spring that attempts to return to its original shape by elastic force outward in the radial direction against this pressing force Can do. Therefore, the stopper 10 is detachably attached to the opening of the inlet 3 of the casing 2 in a compressed state (loose fitting state) so as to be held by an elastic force outward in the radial direction.

  When the flow limiter 1 is assembled, the stopper 10 is attached in a state in which one end surface (left end surface in FIG. 1) of the stopper 10 slightly protrudes from the side end surface of the inlet 3 of the casing 2. Thereby, when the flow limiter 1 is attached to a predetermined position of the common rail main body, one end surface (the left end surface in FIG. 1) of the stopper 10 can be brought into full contact with the common rail main body. The limiter 1 can be reliably set to a predetermined height (position).

  In addition, a pressure damping orifice 16 is formed between the valve 6 slidably provided in the space 5 and the outlet 4 to reduce the flow area. The pressure damping orifice 16 shown in FIG. 1 is an outflow side communication passage formed between the valve seat 7 and the outflow port 4 formed on the outflow side of the space 5 and communicating the space 5 and the outflow port 4. 17 is formed.

  Next, the operation of the above embodiment will be described. When fuel from a common rail (not shown) flows into the inflow port 3, the fuel enters the space 5 through the inflow side communication passage 9 of the stopper 10 and resists the pressing force of the compression coil spring 8 through the valve 6. Then, it is moved to the valve seat 7 side, passes through the hollow portion 14 and the communication port 15 formed in the valve 6, flows out from the outlet 4 through the space 5, and flows into the injector (not shown). . At this time, when the pressure of the fuel flowing in from the inlet 3 is in an appropriate range, the valve 6 receives the force received by the pressure difference between the upstream side and the downstream side of the communication port 15 and the pressing force of the compression coil spring 8. Therefore, it exists in the intermediate position between the stop pad 10 and the valve seat 7.

  When the fuel from the common rail does not flow into the inflow port 3 or hardly, the rear end portion 12 of the valve 6 comes into contact with the stopper 10 by the pressing force of the compression coil spring 8 as shown in FIG. It becomes a state. That is, a reflected wave (pressure wave) propagating from the injector side to the common rail due to the water hammer generated when the injector is closed acts on the valve 6 and the valve 6 moves to the stopper 10 side. At this time, since the pressure damping orifice 16 is formed in the outflow side communication passage 17 that communicates the space 5 and the outlet 4, the water hammer generated when the injector is closed by the pressure damping orifice 16. Thus, the pressure propagating from the injector side to the common rail side is attenuated, and the pressure received by the valve 6 can be made smaller than the conventional pressure. Therefore, it is not necessary to manufacture the stopper 10 that contacts the rear end portion 12 of the valve 6 with a material having a high strength (high hardness) as in the prior art, and the manufacturing cost of the flow limiter can be reduced.

  In addition, a reflected wave (pressure wave) propagating from the injector side to the common rail side by the water hammer generated when the injector is closed is generated by pushing the valve 6 from the injector side to the common rail side, against the stopper 10 of the valve 6. The contact force (pressure) F is transmitted to the common rail main body side and is balanced with the reaction force f because the stopper 10 is attached to the opening of the inlet 3 of the casing 2 in a loosely fitted state. Accordingly, the stopper 10 does not move relative to the opening of the inlet 3 of the casing 2 during operation. Since the conventional stopper is attached to the casing by press fitting, the contact force (pressure) is completely received. Therefore, the stopper has to be manufactured with a material having high strength (high hardness). Since the stopper 10 of the present invention is attached to the casing 2 in a loosely fitted state, the contact force (pressure) is transmitted to the common rail body side. It is not necessary to manufacture with a material of high hardness), and the manufacturing cost of the flow limiter can be reduced.

  On the other hand, when the amount (pressure) of fuel from the common rail flowing into the inflow port 3 becomes a predetermined value or more, the tip portion 11 of the valve 6 is in a state of being fitted to the valve seat 7, and an excessive amount is supplied to the injector. The amount of fuel is prevented from flowing.

  In the above embodiment, the stopper is formed of a cylindrical compression spring as shown in FIG. 2, but the stopper is not limited to this. That is, the stopper is an elastic member having an elastic force outward in the radial direction, and any stopper can be used as long as the stopper can be loosely fitted to the casing by the elastic force.

FIG. 1 is a cross-sectional view showing an embodiment of a flow limiter according to the present invention. FIG. 2 is a perspective view showing an example of a stopper applicable to the above embodiment. FIG. 3 is a partially enlarged cross-sectional view of the flow limiter shown in FIG. FIG. 4 is a cross-sectional view showing a conventional flow limiter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flow limiter 2 Casing 3 Inlet 4 Outlet 5 Space 6 Valve 7 Valve seat 8 Compression coil spring 9 Inflow side communication path 10 Stopper 10a Convex part 10b Concave part 11 Tip part 12 Rear end part 13 Opening part 14 Hollow part 15 Communication Port 16 Pressure damping orifice 17 Outlet side communication passage

Claims (6)

A casing,
An inlet for allowing a predetermined substance to flow into the casing;
An outlet that allows the material flowing in from the inlet to flow out to the outside;
A space formed in the casing to communicate the inlet and the outlet;
A valve slidably provided in the space;
A valve seat formed on the outlet side of the space and allowing the valve to be seated;
An elastic member provided in the space and pressing the valve toward the inlet;
A flow limiter comprising: a stopper provided on the inlet side of the casing and having an inflow side communication path that communicates the inlet and the space;
The stopper is a cylindrical elastic member having an elastic force radially outward, and is attached to the inlet side of the casing by the elastic force. The flow limiter according to claim 1, wherein the stopper is detachably attached to the casing. 3. The flow limiter according to claim 1, wherein the stopper is attached in a state where one end surface of the stopper protrudes from the end surface on the inlet side of the casing when the flow limiter is assembled. . The stopper is wound in a cylindrical shape, a convex portion is formed at one end portion, and a concave portion that engages with the convex portion and receives the convex portion is formed at the other end portion, and is pressed inward in the radial direction. 4. A cylindrical compression spring that attempts to return to its original shape by elastic force outward in the radial direction against the pressing force. The flow limiter described in 1. The pressure damping orifice is formed between the valve provided slidably in the space and the outflow port, according to any one of claims 1 to 4. Flow limiter. Between the valve seat formed on the outflow side of the space and the outflow port, an outflow side communication path that connects the space and the outflow port is formed, and the outflow side communication path includes the The flow limiter according to claim 5, wherein a pressure damping orifice is formed.

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