JP6596542B2 - Valve mechanism and high-pressure fuel supply pump provided with the same - Google Patents

Description

The present invention relates to a valve mechanism and a high-pressure fuel supply pump that includes the valve mechanism and pumps fuel to a fuel injection valve of an internal combustion engine.

  Among direct-injection ties that inject fuel directly into the combustion chamber of an internal combustion engine such as an automobile, high-pressure fuel supply pumps equipped with an electromagnetic intake valve that increases the pressure of the fuel and discharges a desired fuel flow rate are widely used. It is used.

  In Japanese Patent No. 5103838, when a fuel pressure becomes abnormally high in a high-pressure fuel supply pump, a relief valve is provided to relieve the abnormal high-pressure fuel to prevent damage to the high-pressure fuel supply pump and other parts, and at the same time external It plays a role in preventing fuel leakage.

Japanese Patent No. 5103838

  The relief valve has a function of relieving abnormal high pressure generated due to a failure of the high-pressure fuel supply pump. A ball is used for the valve of the relief valve, and this ball valve is pressed against the relief seat by the load of the relief spring. The valve opening pressure of the relief valve is adjusted by the load of the relief spring and is set higher than the maximum fuel pressure used. When the pressure of the high-pressure fuel exceeds the set pressure, the relief valve opens to open the abnormal high-pressure fuel to the low pressure side. In general, the relief valve has the narrowest passage area between the ball valve and the relief seat. If the opening amount of the relief valve is not large enough, the fuel passage area between the ball valve and the relief seat could not be secured sufficiently, and the abnormally high fuel pressure could not be released to a sufficiently low pressure. .

  Therefore, according to Patent Document 1, the clearance between the outer peripheral side surface of the ball holder that transmits the spring load of the relief spring to the ball valve and the member located on the outer periphery is reduced, and the downstream side of the ball valve in the relief valve is reduced. The aperture is provided. As a result, the pressure in the intermediate chamber between the ball holder and the relief seat becomes higher than the low pressure side, and the pressure acts in the valve opening direction of the hole holder, so that the ball holder and the ball valve can be moved with a large stroke. . As a result, the gap between the ball valve and the relief seat can be greatly opened, and thus the fuel having an abnormally high pressure can be released to a sufficiently low pressure.

However, the above prior art has the following problems.
In the relief valve of the above system, it is important to manage the pressure in the intermediate chamber. However, if the ball holder has a large inclination or eccentricity, the differential pressure generated in the gap changes greatly, and the expected effect cannot be obtained. Therefore, an object of the present invention is to provide a valve mechanism that can suppress the inclination, eccentricity, and stroke of the valve holder of the valve with a simple structure.

In order to solve such problems, the present invention opens a pump main body in which a pressurizing chamber for pressurizing fuel is formed, a discharge joint attached to the outer peripheral surface of the pump main body, and a pressure in the discharge joint. A relief valve unit that relieves high pressure fuel, a discharge valve seat, a discharge valve that contacts and separates from the discharge valve seat, a discharge valve spring that biases the discharge valve against the discharge valve seat, and the discharge valve And a discharge valve stopper that supports a spring, and the relief valve unit includes a relief body having a tapered seat portion, a valve seated on the seat portion, and the valve. A holding valve holder, a relief spring that urges the valve toward the seat portion via the valve holder, and one end of the relief spring are supported. The valve holder has a protruding portion protruding toward the opposite side of the seat portion, and the spring stopper has the protruding portion inserted into the inner periphery, and the valve is closed. In this state, the protrusion has an insertion hole that contacts the inner peripheral surface before the valve holder contacts the relief body when the protrusion tilts, and the protrusion closes the valve. The insertion hole is formed with the same diameter from the surface supporting the relief spring toward the end surface side, and is formed so as to protrude from the end surface on the side farther from the seat portion of the spring stopper. A spring stopper is press-fitted and fixed to the inner peripheral surface of the relief body, and a part of the relief spring of the relief valve unit is disposed in the discharge joint, Some Rino is disposed within said pump body, said discharge valve spring of the discharge valve mechanism is provided at a position that does not overlap the relief spring in a radial direction.

  According to the present invention described above, it is possible to provide a valve mechanism that can suppress the inclination, eccentricity, and stroke of the valve holder of the valve with a simple structure. Other configurations, operations, and effects of the present invention will be described in detail in the following examples.

It is a longitudinal cross-sectional view of the high pressure fuel supply pump by a 1st Example. It is another longitudinal cross-sectional view of the high-pressure fuel supply pump by a 1st Example. It is a cross-sectional view of the high-pressure fuel supply pump according to the first embodiment. FIG. 3 is an enlarged longitudinal sectional view of an electromagnetic suction valve of the high-pressure fuel supply pump according to the first embodiment, showing a state where the electromagnetic suction valve is in an open state. It is an expanded sectional view of the relief valve of the high-pressure fuel supply pump by a 1st example, and shows the valve closing state of a relief valve. It is an expanded sectional view of the relief valve of the high-pressure fuel supply pump by a 1st example, and shows the valve opening state of a relief valve. It is a graph which shows the pressure state in each site | part of the high-pressure fuel supply pump by a 1st Example. 1 is an example of a fuel supply system diagram including a high-pressure fuel supply pump according to a first embodiment. It is an expanded sectional view of the relief valve of the high-pressure fuel supply pump by a 1st example, and shows the inclination state of a relief valve. The axial sectional view of the relief valve according to the first embodiment is shown. It is an expanded sectional view near the relief valve of the high-pressure fuel supply pump according to the second embodiment. An axial direction sectional view of a relief valve by a 3rd example is shown. The parts of the relief valve according to the fourth embodiment are shown. An axial sectional view of a relief valve according to a fifth embodiment is shown.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

The configuration and operation of the system will be described with reference to the overall configuration diagram of the system shown in FIG.
A portion surrounded by a broken line indicates a main body of a high-pressure fuel supply pump (hereinafter referred to as a high-pressure pump), and indicates that the mechanism / part shown in the broken line is integrated in the high-pressure pump main body 1. .

  The fuel in the fuel tank 20 is pumped up by the feed pump 21 based on a signal from an engine control unit 27 (hereinafter referred to as ECU), pressurized to an appropriate feed pressure, and passed through the suction pipe 28 to the low pressure fuel inlet 10a of the high pressure pump. Sent to.

  The fuel that has passed through the low-pressure fuel suction port 10a reaches the suction port 31b of the electromagnetic suction valve 300 that constitutes the variable capacity mechanism via the pressure pulsation reducing mechanism 9 and the suction passage 10d.

  The fuel that has flowed into the electromagnetic suction valve 300 passes through the suction valve 30 and flows into the pressurizing chamber 11. The reciprocating power of the plunger 2 is given to the plunger 2 by the cam mechanism 93 of the engine, and the reciprocating motion of the plunger 2 sucks fuel from the suction valve 30 part during the downward stroke of the plunger 2 and pressurizes the fuel during the upward stroke. Then, the fuel is pumped through the discharge valve mechanism 8 to the common rail 23 to which the pressure sensor 26 is mounted, and the injector 24 injects the fuel into the engine based on a signal from the ECU 27.

  The high-pressure pump discharges the fuel flow rate so as to obtain a desired supply fuel by a signal from the ECU 27 to the electromagnetic suction valve.

The configuration and operation of the high-pressure pump will be described with reference to FIGS. 1, 2, 3 and 4.

  In general, the high-pressure pump uses a flange 1 e provided in the pump body 1, is in close contact with the plane of the cylinder head 90 of the internal combustion engine, and is fixed by a plurality of bolts 91. The mounting flange 1e is welded and joined to the pump body 1 at the welded portion 1f to form an annular fixed portion. In this embodiment, laser welding is used.

  An O-ring 61 is fitted into the pump body 1 for sealing between the cylinder head 90 and the pump body 1 to prevent engine oil from leaking outside.

  A cylinder 6 having an end formed in a bottomed cylindrical shape is attached to the pump body 1 so as to guide the reciprocating motion of the plunger 2 and to form a pressurizing chamber 11 therein. Further, the pressurizing chamber 11 communicates with an electromagnetic suction valve 300 for supplying fuel and a discharge valve mechanism 8 for discharging fuel from the pressurizing chamber 11 to the discharge passage. A plurality of communication holes 6b are provided for communicating the annular groove and the pressurizing chamber.

  The cylinder 6 is press-fitted and fixed to the pump body 1 at the outer diameter, and is sealed with a press-fitting portion cylindrical surface so that fuel pressurized from the gap with the pump body 1 does not leak to the low-pressure side. Further, the cylinder 6 has a small diameter portion 6c on the outer diameter on the pressurizing chamber side, and the cylinder 6 acts on the low pressure fuel chamber 10c side when the fuel in the pressurizing chamber 11 is pressurized. By providing the small-diameter portion 1a in the cylinder 6, the cylinder 6 is prevented from coming off to the low-pressure fuel chamber 10c side. By bringing the surfaces into contact with a flat surface in the axial direction, in addition to the sealing of the contact cylindrical surface of the pump body 1 and the cylinder 6, it also functions as a double seal.

  At the lower end of the plunger 2 is provided a tappet 92 that converts the rotational motion of the cam 93 attached to the camshaft of the internal combustion engine into vertical motion and transmits it to the plunger 2. The plunger 2 is pressure-bonded to the tappet 92 by the spring 4 through the retainer 15. Thereby, the plunger 2 can be reciprocated up and down with the rotational movement of the cam 93.

  Further, the plunger seal 13 held at the lower end of the inner periphery of the seal holder 7 is installed in a state in which the plunger 2 is slidably in contact with the outer periphery of the plunger 2 in the lower part of the cylinder 6 in the figure, and the plunger 2 has slid. At this time, the fuel in the sub chamber 7a is sealed to prevent the fuel from flowing into the internal combustion engine. At the same time, lubricating oil (including engine oil) for lubricating the sliding portion in the internal combustion engine is prevented from flowing into the pump body 1.

  A suction joint 51 is attached to the pump body 1. The suction joint is connected to a low-pressure pipe that supplies fuel from the fuel tank 20 of the vehicle, and the fuel is supplied from here to the inside of the high-pressure pump. The suction filter 52 in the suction joint 51 serves to prevent foreign matter existing between the fuel tank 20 and the low-pressure fuel inlet 10a from being absorbed into the high-pressure fuel supply pump by the flow of fuel.

  The fuel that has passed through the low-pressure fuel intake port 10a reaches the intake port 31b of the electromagnetic intake valve 300 via the pressure pulsation reducing mechanism 9 and the low-pressure fuel flow path 10d.

  A discharge valve mechanism 8 is provided at the outlet of the pressurizing chamber 11. The discharge valve mechanism 8 includes a discharge valve seat 8a, a discharge valve mechanism 8b that contacts and separates from the discharge valve seat 8a, a discharge valve spring 8c that urges the discharge valve mechanism 8b toward the discharge valve seat 8a, and a stroke of the discharge valve mechanism 8b ( The discharge valve stopper 8d and the pump main body 1 are joined by welding at the contact portion 8e to block the fuel from the outside.

  In a state where there is no fuel differential pressure in the pressurizing chamber 11 and the discharge valve chamber 12a, the discharge valve mechanism 8b is pressed against the discharge valve seat 8a by the urging force of the discharge valve spring 8c and is closed. Only when the fuel pressure in the pressurizing chamber 11 becomes higher than the fuel pressure in the discharge valve chamber 12a, the discharge valve mechanism 8b opens against the discharge valve spring 8c, and the fuel in the pressurization chamber 11 is discharged from the discharge valve. High pressure is discharged to the common rail 23 through the chamber 12a, the fuel discharge passage 12b, and the fuel discharge port 12. When the discharge valve mechanism 8b is opened, the discharge valve mechanism 8b comes into contact with the discharge valve stopper 8d, and the stroke is limited. Therefore, the stroke of the discharge valve mechanism 8b is appropriately determined by the discharge valve stopper 8d. As a result, the stroke is too large, and it is possible to prevent the fuel discharged at high pressure into the discharge valve chamber 12a from flowing back into the pressurization chamber 11 again due to the delay in closing the discharge valve mechanism 8b. Can be controlled. In addition, when the discharge valve mechanism 8b repeats opening and closing movements, the discharge valve mechanism 8b is guided by the outer peripheral surface of the discharge valve stopper 8d so as to move only in the stroke direction. By doing so, the discharge valve mechanism 8 becomes a check valve that restricts the flow direction of fuel.

  With these configurations, the pressurizing chamber 11 includes the pump housing 1, the electromagnetic suction valve 300, the plunger 2, the cylinder 6, and the discharge valve mechanism 8.

  When the plunger 2 moves in the direction of the cam 93 due to the rotation of the cam 93 and is in the suction stroke state, the volume of the pressurizing chamber 11 increases and the fuel pressure in the pressurizing chamber 11 decreases. When the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure in the suction passage 10d in this process, the suction valve 30 is in an open state, and therefore, through the opening 30e, the communication hole 1a provided in the pump body 1, A groove 6 a of the cylinder 6. It passes through the communication hole 6 b and flows into the pressurizing chamber 11.

  After the plunger 2 completes the suction stroke, the plunger 2 starts to move upward and moves to the compression stroke. Here, the electromagnetic coil 43 remains in a non-energized state and no magnetic biasing force acts. The rod biasing spring 40 is set to have a biasing force necessary and sufficient to keep the suction valve 30 open in a non-energized state. The volume of the pressurizing chamber 11 decreases with the compression movement of the plunger 2. In this state, the fuel once sucked into the pressurizing chamber 11 passes through the opening 30 e of the intake valve 30 in the valve open state once again. Since the pressure is returned to 10d, the pressure in the pressurizing chamber does not increase. This process is called a return process.

  In this state, when a control signal from the engine control unit 27 (hereinafter referred to as ECU) is applied to the electromagnetic intake valve 300, a current flows through the electromagnetic coil 43 via the terminal 46, and the magnetic urging force urges the rod. Since the rod 35 moves in a direction away from the suction valve 30 by overcoming the biasing force of the spring 40, the suction valve 30 is closed by the biasing force by the suction valve biasing spring 33 and the fluid force caused by the fuel flowing into the suction passage 10d. To do. After closing the valve, the fuel pressure in the pressurizing chamber 11 rises with the upward movement of the plunger 2, and when the pressure exceeds the pressure at the fuel discharge port 12, high-pressure discharge of fuel is performed via the discharge valve mechanism 8, and to the common rail 23. Supplied. This stroke is called a discharge stroke.

That is, the compression stroke of the plunger 2 (the upward stroke from the lower start point to the upper start point) includes a return stroke and a discharge stroke. And the quantity of the high-pressure fuel discharged can be controlled by controlling the energization timing to the coil 43 of the electromagnetic suction valve 300. If the timing of energizing the electromagnetic coil 43 is advanced, the ratio of the return stroke during the compression stroke is small and the ratio of the discharge stroke is large. That is, the amount of fuel returned to the suction passage 10d is small and the amount of fuel discharged at high pressure is large. On the other hand, if the energization timing is delayed, the ratio of the return stroke during the compression stroke is large and the ratio of the discharge stroke is small. That is, the amount of fuel returned to the suction passage 10d is large, and the amount of fuel discharged at high pressure is small. The energization timing to the electromagnetic coil 43 is controlled by a command from the ECU 27.
With the configuration described above, the amount of fuel discharged at high pressure can be controlled to the amount required by the internal combustion engine by controlling the energization timing to the electromagnetic coil 43.

  The low-pressure fuel chamber 10 is provided with a pressure pulsation reduction mechanism 9 that reduces and reduces the pressure pulsation generated in the high-pressure pump from spreading to the fuel pipe 28. When the fuel that has once flowed into the pressurizing chamber 11 is returned to the suction passage 10d through the intake valve body 30 that is opened again for capacity control, the fuel returned to the suction passage 10d causes the pressure in the low-pressure fuel chamber 10 to be reduced. Pulsation occurs. However, the pressure pulsation reducing mechanism 9 provided in the low-pressure fuel chamber 10 is formed of a metal diaphragm damper in which two corrugated disk-shaped metal plates are bonded together on the outer periphery and an inert gas such as argon is injected inside. The pressure pulsation is absorbed and reduced by expansion and contraction of the metal damper. Reference numeral 9b denotes a mounting bracket for fixing the metal damper to the inner peripheral portion of the pump body 1, and since it is installed on the fuel passage, a plurality of holes are provided so that fluid can freely go back and forth on the mounting bracket 9b. I have to.

  The plunger 2 has a large-diameter portion 2a and a small-diameter portion 2b, and the volume of the sub chamber 7a increases or decreases as the plunger reciprocates. The sub chamber 7a communicates with the low pressure fuel chamber 10 through a fuel passage 10e. When the plunger 2 descends, fuel flows from the sub chamber 7a to the low pressure fuel chamber 10, and when it rises, fuel flows from the low pressure fuel chamber 10 to the sub chamber 7a.

  As a result, the flow rate of fuel into and out of the pump during the intake stroke or return stroke of the pump can be reduced, and the pressure pulsation generated inside the high-pressure pump is reduced.

  Next, a relief valve is explained in full detail using FIG.5, FIG.6 and FIG.7.

  FIG. 5 shows the closed state of the relief valve 200, and FIG. 6 shows the opened state of the relief valve 200. FIG. 7 shows the state of pressure at each part around the relief valve 200.

  The relief valve 200 includes a relief body 201, a valve 202, a valve holder 203, a relief spring 204, and a spring stopper 205. The relief body 201 is provided with a tapered sheet portion 201a. The valve 202 is loaded with the load of the relief spring 204 via the valve holder 203, pressed against the seat portion 201a, and shuts off the fuel in cooperation with the seat portion 201a. The valve opening pressure of the valve 202 is determined by the load of the relief spring 204. The spring stopper 205 is press-fitted and fixed to the relief body 201, and adjusts the load of the relief spring 204 depending on the press-fitting and fixing position. A gap 211 between the outermost periphery of the valve holder 203 and the inner periphery of the relief body 201 is set to be small so that a throttling effect is generated when fuel passes. The gap is denoted as “B”. In order to generate a necessary pressure difference before and after the gap 211, the gap “B” needs to be small to some extent. In the case of a fuel pump for a direct injection engine, approximately 0.2 mm or less is a standard.

  There is a protrusion 207 at a part of the rear end of the relief holder 203, and there is an insertion part 205a into which the protrusion 207 is inserted. In the present embodiment, the insertion portion 205 a is formed as a part of the spring stopper 205, but may be configured separately from the spring stopper 205. A gap between the protruding portion 207 and the insertion portion 205a is denoted as “A”. The gap “A” functions as a restriction for the inclination of the fuel flow path and the valve holder 203.

  A space surrounded by the three parts of the valve holder 203, the relief body 201, and the valve 202 is referred to as an intermediate chamber 210, a space in which the relief spring 204 is accommodated, and a relief spring chamber 212. The relief spring chamber 12 is interposed via a relief passage 213. Connected to the pressurizing chamber 11. The discharge joint 60 is welded and fixed to the pump body 1 by a welding portion 61 to secure a fuel passage.

  As described above, the valve mechanism according to the present embodiment includes a valve housing portion configured by the relief body 201, a relief spring 204 disposed inside the relief body 201, and a valve that is driven by the relief spring 204 and supports the ball valve 202. Holder part 203. Also, a seat portion 201a on which the ball valve 202 is seated or separated, a projection portion 207 that projects from the valve holder portion 203 to the opposite side of the seat portion 201a, and an insertion portion 205a in which the projection portion 207 is inserted on the inner peripheral side. And comprising. A gap B between the valve holder part 203 and the valve housing part (relief body 201) is formed to be smaller than a gap A between the insertion part 205a and the protruding part 207.

  Here, the axial length corresponding to the protruding portion 207 of the insertion portion 205 a is configured to be longer than the diameter of the protruding portion 207. Thereby, rotation / translation of the valve holder part 203 can be suppressed and the valve holder part 203 and the valve housing part (relief body 201) can be made small so that a throttling effect is generated when fuel passes through the gap between the valve holder part 203 and the valve housing part (relief body 201). .

  Since the protruding portion 207 is long in the axial direction, even if the protruding portion 207 moves to a position where it contacts the insertion portion 205a, the amount of change in the gap between the valve holder portion 203 and the valve housing portion is small. Therefore, this gap can be managed within a desired range. In addition, by utilizing the gap between the protruding portion 207 and the insertion portion 205a as a flow path, it is not necessary to newly form a flow path, and parts can be simplified.

  When the high pressure fuel supply pump is operating normally, the fuel pressurized by the pressurizing chamber 11 passes through the fuel discharge passage 12b and is discharged from the fuel discharge port 12 at a high pressure. FIG. 7 shows a pressure state around the relief valve 200 at this time.

  In this embodiment, the target fuel pressure of the common rail 23 is 14.5 MPa. The pressure in the common rail 23 repeats pulsation with time, but the average value is 14.5 MPa, which is approximately equal to the target fuel pressure.

  Immediately after the start of the pressurization stroke, the pressure in the pressurizing chamber 11 rises rapidly and becomes higher than the pressure in the common rail 23. In this embodiment, the peak value increases to about 23 MPa. Along with this, the pressure of the fuel discharge port 12 also rises and rises to a value close to the pressure in the pressurizing chamber 11. In this embodiment, the peak rises to about 21.5 MPa. Since the intermediate chamber 210 and the gap 211, the relief spring chamber 212, the relief passage 213, and the pressurizing chamber 11 are hydraulically connected, the pressure in the intermediate chamber 210 and the relief spring chamber 212 is the pressure in the pressurizing chamber 11. In this example, the peak is about 21.5 MPa. The valve opening pressure of the relief valve 200 is set to 19 MPa in this embodiment, and the pressure of the fuel discharge port 12 near the inlet of the relief valve 200 exceeds the valve opening pressure, but the relief valve 200 does not open. This is because the pressure in the intermediate chamber 210 and the relief spring chamber 212 also exceeds the valve opening pressure of the relief valve 200, and the difference between the inlet pressure and the outlet pressure of the valve 202 is 19.5 MPa or less.

  When the pressure stroke is shifted to the suction stroke, the pressure in the pressurizing chamber 11 is reduced to a low pressure (about 0.5 MPa), and the pressure in the fuel discharge port 12 is reduced to the same level as the pressure in the common rail 23. Also at this time, the relief valve 200 is not opened because the difference between the inlet pressure and the outlet pressure of the valve 202 is 19.5 MPa or less. That is, when the high-pressure fuel supply pump is operating normally, the relief valve 200 is not opened during the intake stroke and the pressurization stroke.

Next, a case where abnormal high pressure fuel is generated will be described.
When the pressure of the fuel discharge port 12 becomes abnormally high due to a failure of the electromagnetic suction valve 300 of the high pressure fuel supply pump, the abnormal pressure is relieved by the relief valve 200.

  In the suction stroke and the return stroke, the pressure in the pressurizing chamber 11 is low (0.5 MPa or less). When the pressure of the fuel discharge port 12 is 19.5 MPa or more, the pressure difference between the inlet and the outlet of the relief valve 200 is increased. Since the pressure exceeds 19 MPa, the relief valve 200 is opened (the valve 202 is separated from the seat portion 201a), and abnormally high pressure is released to the pressurizing chamber 11.

  In the discharge stroke, as described above, as the pressure in the pressurizing chamber 11 increases, the pressure in the intermediate chamber 210 and the relief spring chamber 212 also increases. Therefore, the pressure difference between the inlet and the outlet of the leaf valve 200 does not exceed 19 MPa. The relief valve 200 does not open. That is, the relief valve 200 cannot open an abnormally high pressure during the discharge stroke. Therefore, only the intake stroke and the return stroke allow the fuel that has become too high in pressure to escape, and it is necessary to sufficiently release the high-pressure fuel within this limited period.

  In the flow path of the relief valve 200, the narrowest part of the passage area is a gap between the seat portion 201a and the valve 202. Increasing this is important for releasing more fuel within a limited time. A gap 211 between the outermost periphery of the valve holder 203 and the inner periphery of the relief body 201 is small enough to cause a pressure loss when the fuel passes. The size of the gap “B” is specifically about 0.005 to 0.2 mm when fuel such as gasoline is used.

  The valve 202 is separated from the seat portion 201 a and the abnormally high pressure fuel at the fuel discharge port 12 flows into the intermediate chamber 210. At this time, since the valve 202 receives the load of the relief spring 204, the valve 202 is separated from the seat portion 201a, but the lift amount is small. The fuel flowing into the intermediate chamber 210 passes through the gap 211 and is released to the pressurizing chamber 11 through the relief spring chamber 212 and the relief passage 213. At this time, a throttling effect is generated in the gap 211, and the pressure in the intermediate chamber 210 becomes higher than that in the relief spring chamber 212, the relief passage 213, and the pressurizing chamber 11, and pressure is generated that pushes the valve holder 203 to the leftward force in the figure. To do. Here, the forces applied to the valve 202 and the valve holder 203 are listed as follows.

(1) Force due to relief spring 204: valve closing direction (2) Force due to differential pressure between fuel discharge port 12 and intermediate chamber 210: Valve opening direction (3) Force due to differential pressure between intermediate chamber 210 and relief spring chamber 212: Open Valve direction When the pressure at the fuel discharge port 12 increases and the differential pressure with respect to the intermediate chamber 210 exceeds the valve opening pressure of the relief valve, the valve 202 is separated. The above force relationship is as follows.
(1) <(2)
With this alone, the lift amount of the valve 202 is small, and a large amount of fuel cannot be released within a limited time. However, when the force (3) is applied, the force in the valve opening direction greatly exceeds (1), and the valve 202 and the valve holder 203 move greatly in the valve opening direction.
(1) ≪ (2) + (3)
The pump body stopper 214 restricts the stroke of the valve holder 203. The relief spring 204 is designed not to be in close contact with the shortest stroke. Therefore, even if the valve holder is lifted to a regulated position, the relief spring 204 does not come into close contact with the flow path inside the relief valve.

  In the force (3), the surface on which the pressure of the intermediate chamber 210 acts is a valve holder, and the pressure receiving area is several times larger than that of the seat portion 201a. Therefore, even if the pressure in the intermediate chamber 210 is less than a fraction of the pressure in the fuel discharge port 12, a force that greatly opens the valve holder 203 can be generated. That is, the differential pressure in the gap 211 need not be so large.

  The relief channel 213 is provided in an arrangement in which the center line is offset with respect to the center line of the valve holder 203. A stopper 214 is located on the center line of the valve holder 203. The stopper portion 214 is disposed on the opposite side of the seat portion 201a with respect to the protruding portion 207, and restricts movement of the valve housing portion (relief body 201) to the opposite side of the seat portion 201a by contacting the protruding portion 207. In this embodiment, since the stopper portion 214 is formed on a part of the pump body 1, it is not necessary to newly provide a stopper member, and the structure can be simplified.

  The pressurizing chamber 11 is disposed on the opposite side of the protruding portion 207 with respect to the stopper portion 214, and the stopper portion 214 has a contact portion that contacts the protruding portion 207 and a flow path to the pressurizing chamber 11 on the outer peripheral side of the contacting portion. Constructing holes are formed. By doing so, the pressure before and after the valve becomes equal while the high-pressure fuel pump is pressurized, and the valve is not opened. The fuel is relieved only when no pressure is applied.

  Further, the valve holder 203 has a larger size in the intersecting direction intersecting with the expansion / contraction direction of the relief spring 204 than in the intersecting direction of the protruding portion 207. That is, the diameter of the valve holder 203 formed in a cylindrical shape is larger than the diameter of the protruding portion 207. By doing so, the entire relief valve can be reduced in size without providing a portion thicker than the valve holder portion.

  The size of the protruding portion 207 in the intersecting direction is formed such that the sheet portion 201a side is larger than the insertion portion 205a side in the expansion / contraction direction. Although the relief spring chamber 212 is connected to the pressurizing chamber 11 and becomes a dead space, the dead space of the relief spring chamber 212 can be reduced.

    The valve holder 203 is formed in a disc shape, and holds the valve 202 at the center. By doing so, the valve holder can be formed basically axisymmetrically and the manufacturing method can be simplified. The insertion portion 205a is formed separately from the relief spring 204 and is located on the inner peripheral side of the valve housing (relief body 201). Thereby, an insertion part can be fixed to the inside of a valve housing, a relief valve can be assembled as a subassembly, and the assembly property of a high pressure fuel pump can be improved.

  When the projecting portion 205a is tilted in any of the up and down directions in a state where the valve 202 is closed, the projecting portion 207 comes before both of the end portions in the up and down direction of the valve holder 203 come into contact with the valve housing (relief body 201). Comes into contact with the insertion portion 205a. By doing so, the maximum inclination angle of the valve holder can be suppressed, and it is possible to prevent the both ends of the valve holder from coming into contact with the valve housing.

  Only one hole into which the protruding portion 207 is inserted is formed in the insertion portion 205a. The pressurizing chamber 11 is disposed on the opposite side of the valve holder 203 with respect to the insertion portion 205a, and the hole into which the protruding portion 207 of the insertion portion 205a is inserted is from the relief spring chamber 212 in which the relief spring 204 is disposed to the pressurizing chamber 11. Form a flow path to Thereby, the processing man-hour of the insertion member can be simplified while securing the flow path of the relief valve.

  As will be described in another embodiment, the valve unit 202 and the valve holder unit 203 may be configured as an integral member. Further, the valve housing (relief body 201) may be constituted by a body to which a valve mechanism is attached.

  The tilt regulation will be described with reference to FIG.

  As described above, there is a gap “A” between the protrusion 207 at the rear end of the relief holder 203 and the insertion portion 205a. The insertion portion 205 a restricts the radial movement of the protruding portion 207 and restricts the inclination of the valve holder 203. In the following description, the radial gap of the gap 211 is indicated by “B”, the axial length is indicated by X, and the distance between the gaps “A” and “B” is indicated by L.

  Relief valves used in high-pressure fuel pumps are generally long and thin, but the relief valves shown in this embodiment are also long and thin. In this embodiment, the distance L between the gap 211 and the insertion portion 205a is long. Therefore, even if the protrusion 207 moves in the gap “A”, the inclination angle of the valve holder 203 is small, and the inclination of the gap 211 can be kept small.

  By regulating the inclination angle of the gap 211, the pressure loss generated in the gap 211 can be suppressed to a predetermined range, and a relief valve using the above-described effect can be realized.

  If it explains with a calculation formula, the maximum inclination angle θmax of the valve holder can be expressed by the following formula.

θmax = tan ⁻¹ (A / L)
By appropriately designing the gap “A” according to the distance L, the maximum inclination angle of the valve holder can be regulated to a desired range, and the pressure loss generated in the gap 211 is designed to be an appropriate range. Can do.

  FIG. 9 a shows an enlarged view of the vicinity of the seat side of the valve holder 203.

  When the valve holder is inclined by the angle θmax, the gap “B” is narrowed by an amount represented by the following equation.

Xsin (θmax)
By designing the gap “A” so that the above value is not larger than the gap “B”, even if the valve holder 203 is tilted, the relief body 201 is prevented from being caught (the gap “B” becomes zero). be able to.

  Regarding the inner diameter of the relief body 201, the inner diameter (C) of the portion forming the gap 211 is formed slightly smaller than the inner diameter (D) on the protruding portion 207 side. By doing so, the distance of the gap “B” of the gap 211 becomes shorter as the valve 202 becomes more distant from the seat portion 201a. When the distance of the gap “B” becomes shorter, the pressure difference generated before and after the gap 211 becomes smaller, and the pressure for lifting the valve holder 203 in the valve opening direction becomes smaller. That is, excessive lift of the valve holder can be prevented. Further, even when the protruding portion 204 collides with the stopper 214, an excessive collision force can be reduced.

  When the distance between the gap 211 and the insertion portion 205a is long, the gap “A” functions as an inclination restriction of the valve holder 203 even if the gap “A” is large, so the gap “A” is used as a fuel flow path in the relief valve. Since the insertion portion 207 has both functions of tilt regulation and flow path with one hole, the structure of the spring stopper 205 can be simplified.

  In the dimensional relationship of this example, the gap “A” is approximately on the order of 0.1 to 3 mm.

  10a and 10b show examples of axial sectional views of the A part and the B part. As the size of the flow path area, it is desirable that the portion A is equal to or larger than the portion B.

  As shown in FIG. 9, the size of the inner circumferential surface of the valve housing part (relief body 201) in the intersecting direction intersecting with the expansion / contraction direction of the relief spring 204 corresponds to the protruding part 207 from the position corresponding to the valve holder part 203. It is formed so that the position becomes larger. That is, the inner peripheral surface of the valve housing part (relief body 201) is narrowed at a position corresponding to the valve holder part 203, and is then configured to spread downstream. As a result, when the seating of the valve 202 is increased, the axial length of the gap formed between the valve holder 203 and the valve housing is reduced, and the pressure difference in the gap is reduced. As a result, the pressure for urging the valve holder 203 in the valve opening direction becomes low, and the lift amount of the valve 202 can be prevented from becoming too large.

  In addition, the clearance gap between the valve holder part 203 and the valve housing part (relief body 201) is formed to 0.4 mm or less. In the case of a gasoline pump for a direct injection engine, this is a practical gap.

  The insertion portion 205a serves as an inclination restricting portion, and when the valve holder portion 203 is inclined, the insertion portion 205a and the protruding portion 207 before the valve holder 203 comes into contact with both ends in the intersecting direction intersecting the axial direction of the valve housing portion (relief body 201). It contacts and regulates the inclination of the valve housing part 203.

  The insertion part 205a which is an inclination restricting part is configured separately from the relief spring 204 and the valve housing part (relief body 201). The insertion portion 205a, which is an inclination restricting portion, guides the protruding portion 207, and the axial size corresponding to the protruding portion 207 of the inclination restricting portion is configured to be larger than the size of the protruding portion 207 in the intersecting direction. . By adopting such a configuration, the insertion portion 205a, which is an inclination restricting portion, can perform its guide function. In the present embodiment, the valve holder portion 203 and the protruding portion 207 are configured as an integral member.

  As described above, the high-pressure fuel supply pump of this embodiment includes the pressurizing chamber 11 that pressurizes the fuel, the discharge valve mechanism 8 that discharges the fuel pressurized in the pressurizing chamber 11, and the discharge valve mechanism 8. The fuel on the discharge side is relieved to the pressurizing chamber 11 or the low-pressure channel (low-pressure fuel chamber 10c, low-pressure fuel channel 10d, etc.) via the relief passage. The valve mechanism described above is attached to the relief passage 212.

  As a result of intensive studies, the present inventors have discovered that if the lift amount of the ball holder is too large, the springs are in close contact and block the road itself. When such a state occurs, in the vehicle, a problem has been found that the piping pressure increases excessively or becomes unstable at the time of abnormality. On the other hand, according to the embodiment of the present invention described above, it is possible to prevent the spring from adhering and block the flow path itself, and to prevent the pipe pressure from rising excessively or becoming unstable at the time of abnormality. It becomes possible to do.

Another embodiment of the present invention will be described with reference to FIG.
In this structure, a member corresponding to the relief body 201 of the first embodiment is formed in a part of the pump body 1. Further, members corresponding to the insertion portion 205 a and the stopper member 214 are also formed in a part of the pump main body 1. The relief spring chamber 212 is provided with a flow path 213 communicating with the pressurizing chamber 11. There is a gap “A” between the insertion portion 205a and the protruding portion 207, which forms a flow path for fuel to be pushed out when the protruding portion 207 enters and exits. By doing so, the relief body 201, the stopper member 214, and the spring stopper 205 can be reduced, and the structure can be simplified. The same effect as that of the first embodiment can be expected for the tilt regulation of the relief body 203.

Another embodiment of the present invention will be described with reference to FIG.
In this structure, the spring stopper 205 is press-molded with a thin plate. By doing so, the productivity of parts can be improved and the cost can be reduced compared to cutting. As for the effects, the same effects as those of the first and second embodiments can be expected.

Another embodiment of the present invention will be described with reference to FIGS.
The spring stopper 205 is provided with a flow path portion 205b adjacent to the insertion portion 205a. By doing so, the flow path leading from the relief spring chamber 212 to the flow path 213 can be further expanded. By providing a flow path separately from the gap “A”, the degree of freedom in designing the gap “A” is increased. As a result, for example, the gaps “A” and “B” can be designed to be smaller.

  In the first to fourth embodiments, the valve 202 and the valve holder 203 are described as separate parts, but the same effect can be obtained even with a part in which these are integrally formed.

Another embodiment of the present invention will be described with reference to FIG.
The valve mechanism 200 according to the present embodiment includes a valve housing portion configured by a relief body 201, a relief spring 204 disposed inside the relief body 201, and a valve holder portion that is driven by the relief spring 204 and supports the ball valve 202. 203. Further, a seat part 201a on which the ball valve 202 is seated or separated, a projecting part 207 projecting from the valve holder part 203 to the opposite side of the seat part 201a, and an insertion part 208a into which the projecting part 207 is inserted on the inner peripheral side. And comprising. And the clearance gap between the valve holder part 203 and the valve housing part (relief body 201) is formed smaller than the clearance A between the insertion part 208a and the protrusion part 207.

  In the present embodiment, the upstream end portion of the insertion portion 208 a of the inclination restricting portion 208 is located on the upstream side of the central portion of the relief spring 204 from the downstream side. A flow path to the pressurizing chamber 11 is formed in the inclination restricting portion 208 on the downstream side of the spring stopper 205 and on the outer peripheral side of the insertion portion 205a. The inclination restricting portion 208 is fixed to the valve housing portion (relief body 201) on the downstream side. The spring stopper 205 is fixed to the inclination restricting portion 208.

The calculation formula described in paragraph [0089] is obtained by bringing the insertion portion 208a that restricts the inclination of the protrusion 207 closer to the gap between the valve holder portion 203 and the valve housing portion (relief body 201).
θmax = tan-1 (A / L)
L corresponding to is reduced, and A can be reduced while maintaining θmax. Such a configuration is practical when it is desired to design a large pressure difference before and after the gap A.

DESCRIPTION OF SYMBOLS 1 Pump main body 2 Plunger 6 Cylinder 7 Seal holder 8 Discharge valve mechanism 9 Pressure pulsation reduction mechanism 10a Low pressure fuel suction port 11 Pressurization chamber 12 Fuel discharge port 13 Plunger seal 30 Suction valve 40 Rod biasing spring 43 Electromagnetic coil 100 Pressure pulsation propagation Prevention mechanism 101 Valve seat 102 Valve 103 Spring 104 Spring stopper 200 Relief valve 201 Relief body 201a Seat part 202 Valve 203 Valve holder 204 Relief spring 205 Spring stopper 205a insertion part 207 Projection part 212 Relief spring chamber 214 Stopper member 300 Electromagnetic suction valve

Claims (2)

A pump body in which a pressurizing chamber for pressurizing fuel is formed;
A discharge joint attached to the outer peripheral surface of the pump body;
A relief valve unit that opens by the pressure in the discharge joint to relieve high-pressure fuel;
A discharge valve comprising: a discharge valve seat; a discharge valve that contacts and separates from the discharge valve sheet; a discharge valve spring that biases the discharge valve toward the discharge valve sheet; and a discharge valve stopper that supports the discharge valve spring. A mechanism ,
The relief valve unit includes a relief body having a tapered seat portion, a valve seated on the seat portion, a valve holder that holds the valve, and the valve to the seat portion via the valve holder. A relief spring that urges toward the end, and a spring stopper that supports one end of the relief spring,
The valve holder has a protruding portion that protrudes toward the opposite side of the seat portion,
In the spring stopper, the protrusion is inserted into the inner periphery, and the protrusion comes into the inner periphery before the valve holder contacts the relief body when the protrusion is inclined when the valve is closed. an insertion hole you contact with the surface,
The protruding portion is formed so as to protrude from an end surface of the spring stopper far from the seat portion in a state where the valve is closed ,
The insertion hole is formed with the same diameter from the surface supporting the relief spring toward the end surface side,
The spring stopper is press-fitted and fixed to the inner peripheral surface of the relief body,
A portion of the relief spring of the relief valve unit is disposed within the discharge joint, and a remaining portion of the relief spring is disposed within the pump body;
Wherein the discharge valve spring of the discharge valve mechanism is a high pressure fuel supply pump according to claim Rukoto provided at a position that does not overlap the relief spring in a radial direction. The high-pressure fuel supply pump according to claim 1,
The high-pressure fuel supply pump, wherein the spring stopper has a bottom portion in which the insertion hole is formed and a cylindrical portion press-fitted and fixed to the inner peripheral surface of the relief body, and is formed of a thin plate. .

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