Invention name: Fuel pump
Technical field
[0001]
　The present invention relates to a fuel pump that supplies fuel to an engine at high pressure.
Background technology
[0002]
　The fuel pump is described in, for example, Patent Document 1. The high-pressure fuel supply pump described in Patent Document 1 includes a housing, an intake valve, a discharge valve, and a relief valve.
The housing has a cylinder, which is a stepped tubular space that accommodates a cylinder liner that slidably holds the plunger and forms a pressurizing chamber. The suction valve opens without supplying a current to the electromagnetic solenoid, and when a current is supplied to the electromagnetic solenoid, the valve opens and sucks fuel into the pressurizing chamber.
[0003]
　The discharge valve is attached to the discharge valve accommodating portion of the housing, and the discharge valve accommodating portion communicates with the pressurizing chamber via the fuel discharge hole. The high-pressure fuel pressurized in the pressurizing chamber is supplied to the discharge valve. The discharge valve opens when the pressure of the supplied fuel exceeds a predetermined pressure, and the fuel that has passed through the discharge valve is pressure-fed to the accumulator.
[0004]
　Further, the relief valve is assembled to the relief valve accommodating portion of the housing, and the relief valve accommodating portion communicates with the high pressure region on the downstream side of the discharge valve and communicates with the pressurizing chamber via the communication passage. There is. The relief valve opens when the pressure of the fuel in the high pressure region exceeds a specific pressure, and returns the high pressure fuel to the pressurizing chamber.
Prior art literature
Patent documents
[0005]
Patent Document 1: Japanese Unexamined Patent Publication No. 2019-2374
Outline of the invention
Problems to be solved by the invention
[0006]
　However, in the high-pressure fuel supply pump described in Patent Document 1, the shape of the intersection between the pressurizing chamber and the communication passage is complicated. As a result, the processing of the connecting passages becomes complicated, which hinders the improvement of the productivity of the high-pressure fuel supply pump.
[0007]
　An object of the present invention is to provide a fuel pump capable of improving productivity in consideration of the above problems.
Means to solve problems
[0008]
　In order to solve the above problems and achieve the object of the present invention, the fuel pump of the present invention includes a pump body, a plunger, a suction valve, and a relief valve. The plunger reciprocates in the first chamber, which is a columnar space provided in the pump body. The suction valve sucks fuel into the first chamber and the pressurizing chamber formed by the plunger. The relief valve opens when the fuel pressure on the downstream side of the pressurizing chamber exceeds the set value, and returns the fuel to the pressurizing chamber. The pump body has a second chamber in which a relief valve is arranged, and a communication hole that communicates the first chamber and the second chamber. The diameter of the communication hole is the same as the diameter of the first chamber, and the communication hole extends the first chamber.
Effect of the invention
[0009]
　According to the fuel pump having the above configuration, productivity can be improved.
　Issues, configurations and effects other than those described above will be clarified by the following description of the embodiments.
A brief description of the drawing
[0010]
FIG. 1 is an overall configuration diagram of a fuel supply system using a high-pressure fuel supply pump according to an embodiment of the present invention.
FIG. 2 is a vertical sectional view (No. 1) of a high-pressure fuel supply pump according to an embodiment of the present invention.
FIG. 3 is a vertical cross-sectional view (No. 2) of a high-pressure fuel supply pump according to an embodiment of the present invention.
FIG. 4 is a horizontal sectional view of the high-pressure fuel supply pump according to the embodiment of the present invention as viewed from above.
FIG. 5 is a vertical cross-sectional view (No. 3) of a high-pressure fuel supply pump according to an embodiment of the present invention.
Embodiment for carrying out the invention
[0011]
1. Embodiment
　The high-pressure fuel supply pump according to the embodiment of the present invention will be described below. The common members in each figure are designated by the same reference numerals.
[0012]
[Fuel Supply System]
　Next, a fuel supply system using a high-pressure fuel supply pump (fuel pump) according to the present embodiment will be described with reference to FIG.
　FIG. 1 is an overall configuration diagram of a fuel supply system using a high-pressure fuel supply pump according to the present embodiment.
[0013]
　As shown in FIG. 1, the fuel supply system includes a high-pressure fuel supply pump (fuel pump) 100, an ECU (Engine Control Unit) 101, a fuel tank 103, a common rail 106, and a plurality of injectors 107. .. The parts of the high-pressure fuel supply pump 100 are integrally incorporated in the pump body 1.
[0014]
　The fuel in the fuel tank 103 is pumped by the feed pump 102 that is driven based on the signal from the ECU 101. The pumped fuel is pressurized to an appropriate pressure by a pressure regulator (not shown) and sent to the low pressure fuel suction port 51 of the high pressure fuel supply pump 100 through the low pressure pipe 104.
[0015]
　The high-pressure fuel supply pump 100 pressurizes the fuel supplied from the fuel tank 103 and pumps it to the common rail 106. A plurality of injectors 107 and a fuel pressure sensor 105 are mounted on the common rail 106. The plurality of injectors 107 are mounted according to the number of cylinders (combustion chambers), and inject fuel according to the drive current output from the ECU 101. The fuel supply system of the present embodiment is a so-called direct injection engine system in which the injector 107 injects fuel directly into the cylinder cylinder of the engine.
[0016]
　The fuel pressure sensor 105 outputs the detected pressure data to the ECU 101. The ECU 101 has an appropriate injection fuel amount (target injection fuel length) and an appropriate fuel pressure (target) based on the engine state amount (for example, crank rotation angle, throttle opening, engine rotation speed, fuel pressure, etc.) obtained from various sensors. Fuel pressure) etc. are calculated.
[0017]
　Further, the ECU 101 controls the drive of the high-pressure fuel supply pump 100 and the plurality of injectors 107 based on the calculation results such as the fuel pressure (target fuel pressure). That is, the ECU 101 has a pump control unit that controls the high-pressure fuel supply pump 100 and an injector control unit that controls the injector 107.
[0018]
　The high-pressure fuel supply pump 100 includes a pressure pulsation reducing mechanism 9, an electromagnetic suction valve 3 which is a capacity variable mechanism, a relief valve 4 (see FIG. 2), and a discharge valve 8. The fuel flowing in from the low-pressure fuel suction port 51 reaches the suction port 31b of the electromagnetic suction valve 3 via the pressure pulsation reduction mechanism 9 and the suction passage 10b.
[0019]
　The fuel that has flowed into the electromagnetic suction valve 3 passes through the valve portion 32, flows through the suction passage 1d formed in the pump body 1, and then flows into the pressurizing chamber 11. A plunger 2 is inserted into the pressurizing chamber 11 so as to be reciprocating. The plunger 2 reciprocates when power is transmitted by the cam 91 of the engine (see FIG. 2).
[0020]
　In the pressurizing chamber 11, fuel is sucked from the electromagnetic suction valve 3 in the descending stroke of the plunger 2, and the fuel is pressurized in the ascending stroke. When the fuel pressure in the pressurizing chamber 11 exceeds a predetermined value, the discharge valve 8 opens, and high-pressure fuel is pressure-fed to the common rail 106 via the discharge passage 12a. The fuel discharge by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic suction valve 3. The opening and closing of the electromagnetic suction valve 3 is controlled by the ECU 101.
[0021]
[High Pressure Fuel Supply Pump]
　Next, the configuration of the high pressure fuel supply pump 100 will be described with reference to FIGS. 2 to 5.
　FIG. 2 is a vertical cross-sectional view (No. 1) of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the horizontal direction. FIG. 3 is a vertical cross-sectional view (No. 2) of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the horizontal direction. FIG. 4 is a horizontal cross-sectional view of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the vertical direction. Further, FIG. 5 is a vertical cross-sectional view (No. 3) of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the horizontal direction.
[0022]
　As shown in FIGS. 2 to 5, the pump body 1 of the high-pressure fuel supply pump 100 is formed in a substantially columnar shape. As shown in FIGS. 2 and 3, the pump body 1 is provided with a first chamber 1a, a second chamber 1b, a third chamber 1c, and a suction passage 1d inside. Further, the pump body 1 is in close contact with the fuel pump mounting portion 90 and is fixed by a plurality of bolts (screws) (not shown).
[0023]
　The first chamber 1a is a columnar space provided in the pump body 1, and the center line 1A of the first chamber 1a coincides with the center line of the pump body 1. One end of the plunger 2 is inserted into the first chamber 1a, and the plunger 2 reciprocates in the first chamber 1a. One end of the first chamber 1a and the plunger 2 forms a pressurizing chamber 11.
[0024]
　The second chamber 1b is a columnar space provided in the pump body 1, and the center line of the second chamber 1b is orthogonal to the center line of the pump body 1 (first chamber 1a). A relief valve 4 is arranged in the second chamber 1b. The diameter of the second chamber 1b is smaller than the diameter of the first chamber 1a.
[0025]
　Further, the first chamber 1a and the second chamber 1b are communicated with each other by a circular communication hole 1e. The diameter of the communication hole 1e is the same as the diameter of the first chamber 1a, and the communication hole 1e extends one end of the first chamber 1a. The diameter of the communication hole 1e is larger than the outer diameter of the plunger 2. The center line of the communication hole 1e is orthogonal to the center line of the second chamber 1b.
[0026]
　As shown in FIGS. 3 and 5, the diameter of the communication hole 1e is larger than the diameter of the second chamber 1b. The communication hole 1e has a tapered surface 1f whose diameter decreases toward the second chamber 1b in a cross section orthogonal to the center line of the second chamber 1b. As a result, the fuel that has passed through the relief valve 4 arranged in the second chamber 1b can smoothly return to the pressurizing chamber 11 along the tapered surface 1f.
[0027]
　The third chamber 1c is a columnar space provided in the pump body 1 and is continuous with the other end of the first chamber 1a. The center line of the third chamber 1c coincides with the center line 1A of the first chamber 1a and the center line of the pump body 1, and the diameter of the third chamber 1c is larger than the diameter of the first chamber 1a. A cylinder 6 for guiding the reciprocating movement of the plunger 2 is arranged in the third chamber 1c.
[0028]
　The cylinder 6 is formed in a cylindrical shape, and is press-fitted into the third chamber 1c of the pump body 1 on the outer peripheral side thereof. Then, one end of the cylinder 6 is in contact with the top surface of the third chamber 1c (the step portion between the first chamber 1a and the third chamber 1c). The plunger 2 is slidably in contact with the inner peripheral surface of the cylinder 6.
[0029]
　An O-ring 93 showing a specific example of the seat member is interposed between the fuel pump mounting portion 90 and the pump body 1. The O-ring 93 prevents engine oil from leaking to the outside of the engine (internal combustion engine) through between the fuel pump mounting portion 90 and the pump body 1.
[0030]
　A tappet 92 is provided at the lower end of the plunger 2 to convert the rotational motion of the cam 91 attached to the camshaft of the engine into a vertical motion and transmit it to the plunger 2. The plunger 2 is urged toward the cam 91 by a spring 16 via a retainer 15 and is crimped to the tappet 92. The tappet 92 reciprocates as the cam 91 rotates. The plunger 2 reciprocates together with the tappet 92 to change the volume of the pressurizing chamber 11.
[0031]
　Further, a seal holder 17 is arranged between the cylinder 6 and the retainer 15. The seal holder 17 is formed in a cylindrical shape into which the plunger 2 is inserted, and has an auxiliary chamber 17a at the upper end portion on the cylinder 6 side. Further, the seal holder 17 holds the plunger seal 18 at the lower end portion on the retainer 15 side.
[0032]
　The plunger seal 18 is slidably in contact with the outer periphery of the plunger 2 and seals the fuel in the sub chamber 17a when the plunger 2 reciprocates so that the fuel in the sub chamber 17a does not flow into the engine. There is. Further, the plunger seal 18 prevents the lubricating oil (including the engine oil) that lubricates the sliding portion in the engine from flowing into the inside of the pump body 1.
[0033]
　In FIG. 2, the plunger 2 reciprocates in the vertical direction. When the plunger 2 is lowered, the volume of the pressurizing chamber 11 is expanded, and when the plunger 2 is raised, the volume of the pressurizing chamber 11 is decreased.
That is, the plunger 2 is arranged so as to reciprocate in the direction of expanding and contracting the volume of the pressurizing chamber 11.
[0034]
　The plunger 2 has a large diameter portion 2a and a small diameter portion 2b. When the plunger 2 reciprocates, the large diameter portion 2a and the small diameter portion 2b are located in the sub chamber 17a. Therefore, the volume of the sub chamber 17a increases or decreases due to the reciprocating motion of the plunger 2.
[0035]
　The sub chamber 17a communicates with the low pressure fuel chamber 10 by a fuel passage 10c (see FIG. 5). When the plunger 2 is lowered, a fuel flow is generated from the sub chamber 17a to the low pressure fuel chamber 10, and when the plunger 2 is raised, a fuel flow is generated from the low pressure fuel chamber 10 to the sub chamber 17a. As a result, the fuel flow rate inside and outside the pump in the suction stroke or the return stroke of the high-pressure fuel supply pump 100 can be reduced, and the pressure pulsation generated inside the high-pressure fuel supply pump 100 can be reduced.
[0036]
　As shown in FIG. 3, a low-pressure fuel chamber 10 is provided in the upper part of the pump body 1 of the high-pressure fuel supply pump 100, and a suction joint 5 is attached to the side surface portion of the pump body 1. The suction joint 5 is connected to a low pressure pipe 104 through which fuel supplied from the fuel tank 103 (see FIG. 1) is passed. The fuel of the fuel tank 103 is supplied to the inside of the pump body 1 from the suction joint 5.
[0037]
　The suction joint 5 has a low pressure fuel suction port 51 connected to the low pressure pipe 104 and a suction flow path 52 communicating with the low pressure fuel suction port 51. The fuel that has passed through the suction flow path 52 passes through the suction filter 53 provided inside the pump body 1 and is supplied to the low pressure fuel chamber 10. The suction filter 53 removes foreign matter present in the fuel and prevents the foreign matter from entering the high-pressure fuel supply pump 100.
[0038]
　The low-pressure fuel chamber 10 is provided with a low-pressure fuel flow path 10a and a suction passage 10b (see FIG. 2). The low pressure fuel flow path 10a is provided with a pressure pulsation reducing mechanism 9. When the fuel flowing into the pressurizing chamber 11 is returned to the suction passage 10b through the electromagnetic suction valve 3 in the opened state again, pressure pulsation occurs in the low pressure fuel chamber 10. The pressure pulsation reducing mechanism 9 reduces that the pressure pulsation generated in the high-pressure fuel supply pump 100 spreads to the low-pressure pipe 104.
[0039]
　The pressure pulsation reducing mechanism 9 is formed of a metal diaphragm damper in which two corrugated disk-shaped metal plates are bonded together on the outer periphery thereof and an inert gas such as argon is injected therein. The metal diaphragm damper of the pressure pulsation reducing mechanism 9 absorbs or reduces the pressure pulsation by expanding and contracting.
[0040]
　The suction passage 10b communicates with the suction port 31b (see FIG. 2) of the electromagnetic suction valve 3, and the fuel passing through the low pressure fuel flow path 10a reaches the suction port 31b of the electromagnetic suction valve 3 via the suction passage 10b. To reach.
[0041]
　As shown in FIGS. 2 and 4, the electromagnetic suction valve 3 is inserted into a lateral hole formed in the pump body 1. The electromagnetic suction valve 3 has a suction valve seat 31 press-fitted into a lateral hole formed in the pump body 1, a valve portion 32, a rod 33, a rod urging spring 34, an electromagnetic coil 35, and an anchor 36. is doing.
[0042]
　The suction valve seat 31 is formed in a cylindrical shape, and a seating portion 31a is provided on the inner peripheral portion. Further, the suction valve seat 31 is formed with a suction port 31b that reaches the inner peripheral portion from the outer peripheral portion. The suction port 31b communicates with the suction passage 10b in the low pressure fuel chamber 10 described above.
[0043]
　A stopper 37 facing the seating portion 31a of the suction valve seat 31 is arranged in the lateral hole formed in the pump body 1, and the valve portion 32 is arranged between the stopper 37 and the seating portion 31a. Further, a valve urging spring 38 is interposed between the stopper 37 and the valve portion 32.
The valve urging spring 38 urges the valve portion 32 toward the seating portion 31a.
[0044]
　When the valve portion 32 comes into contact with the seating portion 31a, the communication portion between the suction port 31b and the pressurizing chamber 11 is closed, and the electromagnetic suction valve 3 is closed. On the other hand, when the valve portion 32 comes into contact with the stopper 37, the communication portion between the suction port 31b and the pressurizing chamber 11 is opened, and the electromagnetic suction valve 3 is opened.
[0045]
　The rod 33 penetrates the cylinder hole of the suction valve seat 31, and one end thereof is in contact with the valve portion 32. The rod urging spring 34 urges the valve portion 32 via the rod 33 in the valve opening direction on the stopper 37 side. One end of the rod urging spring 34 is engaged with the other end of the rod 33, and the other end of the rod urging spring 34 is engaged with a magnetic core 39 arranged so as to surround the rod urging spring 34. ing.
[0046]
　The anchor 36 faces the end face of the magnetic core 39. Further, the anchor 36 is engaged with a flange provided in the middle portion of the rod 33. The electromagnetic coil 35 is arranged so as to go around the magnetic core 39. A terminal member 40 is electrically connected to the electromagnetic coil 35, and a current flows through the terminal member 40.
[0047]
　In a non-energized state in which no current is flowing through the electromagnetic coil 35, the rod 33 is urged in the valve opening direction by the urging force of the rod urging spring 34, and the valve portion 32 is pressed in the valve opening direction.
As a result, the valve portion 32 separates from the seating portion 31a and comes into contact with the stopper 37, and the electromagnetic suction valve 3 is in the valve open state. That is, the electromagnetic suction valve 3 is a normally open type that opens in a non-energized state.
[0048]
　In the open state of the electromagnetic suction valve 3, the fuel of the suction port 31b passes between the valve portion 32 and the seating portion 31a, and is applied through a plurality of fuel passage holes (not shown) of the stopper 37 and the suction passage 1d. It flows into the pressure chamber 11. In the valve open state of the electromagnetic suction valve 3, the valve portion 32 comes into contact with the stopper 37, so that the position of the valve portion 32 in the valve opening direction is restricted. The gap existing between the valve portion 32 and the seated portion 31a in the valve open state of the electromagnetic suction valve 3 is the movable range of the valve portion 32, and this is the valve opening stroke.
[0049]
　When a current flows through the electromagnetic coil 35, the anchor 36 is attracted in the valve closing direction by the magnetic attraction force of the magnetic core 39. As a result, the anchor 36 moves against the urging force of the rod urging spring 34 and comes into contact with the magnetic core 39. When the anchor 36 moves in the valve closing direction on the magnetic core 39 side, the rod 33 with which the anchor 36 engages moves together with the anchor 36. As a result, the valve portion 32 is released from the urging force in the valve opening direction and moves in the valve closing direction by the urging force by the valve urging spring 38. Then, when the valve portion 32 comes into contact with the seated portion 31a of the suction valve seat 31, the electromagnetic suction valve 3 is closed.
[0050]
　As shown in FIGS. 4 and 5, the discharge valve 8 is connected to the outlet side (downstream side) of the pressurizing chamber 11. The discharge valve 8 includes a discharge valve seat 81 that communicates with the pressurizing chamber 11, a valve portion 82 that communicates with and separates from the discharge valve seat 81, and a discharge valve spring 83 that urges the valve portion 82 toward the discharge valve seat 81. It has a discharge valve stopper 84 that determines the stroke (moving distance) of the valve portion 82.
[0051]
　Further, the discharge valve 8 has a plug 85 for blocking the leakage of fuel to the outside. The discharge valve stopper 84 is press-fitted into the plug 85. The plug 85 is joined to the pump body 1 by welding at the welded portion 86. The discharge valve 8 communicates with the discharge valve chamber 87 opened and closed by the valve portion 82. The discharge valve chamber 87 is formed in the pump body 1.
[0052]
　The pump body 1 is provided with a horizontal hole communicating with the second chamber 1b (see FIG. 2), and a discharge joint 12 is inserted into the horizontal hole. The discharge joint 12 has the above-mentioned discharge passage 12a communicating with the lateral hole of the pump body 1 and the discharge valve chamber 87, and the fuel discharge port 12b which is one end of the discharge passage 12a. The fuel discharge port 12b of the discharge joint 12 communicates with the common rail 106. The discharge joint 12 is fixed to the pump body 1 by welding by a welded portion 12c.
[0053]
　When there is no difference in fuel pressure (fuel differential pressure) between the pressurizing chamber 11 and the discharge valve chamber 87, the valve portion 82 is crimped to the discharge valve seat 81 by the urging force of the discharge valve spring 83, and the discharge valve 8 is pressed. Is closed. When the fuel pressure in the pressurizing chamber 11 becomes higher than the fuel pressure in the discharge valve chamber 87, the valve portion 82 moves against the urging force of the discharge valve spring 83, and the discharge valve 8 is opened. Become.
[0054]
　When the discharge valve 8 is closed, the (high pressure) fuel in the pressurizing chamber 11 passes through the discharge valve 8 and reaches the discharge valve chamber 87. Then, the fuel that has reached the discharge valve chamber 87 is discharged to the common rail 106 (see FIG. 1) via the fuel discharge port 12b of the discharge joint 12. With the above configuration, the discharge valve 8 functions as a check valve that limits the flow direction of fuel.
[0055]
　The relief valve 4 shown in FIG. 2 operates when a problem occurs in the common rail 106 or a member beyond the common rail 106 and the pressure of the common rail 106 exceeds a predetermined pressure and becomes high, and the fuel in the discharge passage 12a is discharged. It is a valve configured to return to the pressurizing chamber 11. The relief valve 4 is arranged at a position higher than that of the discharge valve 8 (see FIG. 5) in the direction (vertical direction) in which the plunger 2 reciprocates.
[0056]
　The relief valve 4 has a relief spring 41, a relief valve holder 42, a valve portion 43, and a seat member 44. The relief valve 4 is inserted from the discharge joint 12 and arranged in the second chamber 1b. One end of the relief spring 41 is in contact with the pump body 1 (one end of the second chamber 1b), and the other end is in contact with the relief valve holder 42. The relief valve holder 42 is engaged with the valve portion 43, and the urging force of the relief spring 41 acts on the valve portion 43 via the relief valve holder 42.
[0057]
　The valve portion 43 is pressed by the urging force of the relief spring 41 and blocks the fuel passage of the seat member 44. The moving direction of the valve portion 43 (relief valve holder 42) is orthogonal to the direction in which the plunger 2 reciprocates. The center line of the relief valve 4 (the center line of the relief valve holder 42) is orthogonal to the center line of the plunger 2.
[0058]
　The seat member 44 has a fuel passage facing the valve portion 43, and the side of the fuel passage opposite to the valve portion 43 communicates with the discharge passage 12a. The movement of fuel between the pressurizing chamber 11 (upstream side) and the seat member 44 (downstream side) is blocked by the valve portion 43 contacting (adhering) to the seat member 44 and blocking the fuel passage.
[0059]
　When the pressure in the common rail 106 and the member beyond it becomes high, the fuel on the seat member 44 side presses the valve portion 43 and moves the valve portion 43 against the urging force of the relief spring 41. As a result, the valve portion 43 opens, and the fuel in the discharge passage 12a returns to the pressurizing chamber 11 through the fuel passage of the seat member 44. Therefore, the pressure for opening the valve portion 43 is determined by the urging force of the relief spring 41.
[0060]
　The moving direction of the valve portion 43 (relief valve holder 42) in the relief valve 4 is different from the moving direction of the valve portion 82 in the discharge valve 8 described above. That is, the moving direction of the valve portion 82 in the discharge valve 8 is the first radial direction of the pump body 1, and the moving direction of the valve portion 43 in the relief valve 4 is a second diameter different from the first radial direction of the pump body 1. The direction. As a result, the discharge valve 8 and the relief valve 4 can be arranged at positions where they do not overlap each other in the vertical direction, and the space inside the pump body 1 can be effectively utilized to reduce the size of the pump body 1. ..
[0061]
[Operation of high-pressure fuel pump]
　Next, the operation of the high-pressure fuel pump according to the present embodiment will be described with reference to FIGS. 2 and 4.
[0062]
　In FIG. 2, when the plunger 2 is lowered and the electromagnetic suction valve 3 is opened, fuel flows into the pressurizing chamber 11 from the suction passage 1d. Hereinafter, the process in which the plunger 2 descends is referred to as an inhalation process. On the other hand, when the plunger 2 rises and the electromagnetic suction valve 3 is closed, the fuel in the pressurizing chamber 11 is boosted, passes through the discharge valve 8, and is pressure-fed to the common rail 106 (see FIG. 1). To. Hereinafter, the process of ascending the plunger 2 is referred to as an ascending process.
[0063]
　As described above, if the electromagnetic suction valve 3 is closed during the ascending step, the fuel sucked into the pressurizing chamber 11 during the suction stroke is pressurized and discharged to the common rail 106 side. On the other hand, if the electromagnetic suction valve 3 is opened during the ascending step, the fuel in the pressurizing chamber 11 is pushed back to the suction passage 1d side and is not discharged to the common rail 106 side. In this way, the fuel discharge by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic suction valve 3. The opening and closing of the electromagnetic suction valve 3 is controlled by the ECU 101.
[0064]
　In the suction stroke, the volume of the pressurizing chamber 11 increases, and the fuel pressure in the pressurizing chamber 11 decreases. As a result, the fluid differential pressure between the suction port 31b and the pressurizing chamber 11 (hereinafter referred to as “fluid differential pressure before and after the valve portion 32”) becomes small. When the urging force of the rod urging spring 34 becomes larger than the fluid differential pressure before and after the valve portion 32, the rod 33 moves in the valve opening direction, and the valve portion 32 separates from the seating portion 31a of the suction valve seat 31. , The electromagnetic suction valve 3 is opened.
[0065]
　When the electromagnetic suction valve 3 is opened, the fuel in the suction port 31b passes between the valve portion 32 and the seating portion 31a, passes through a plurality of fuel passage holes (not shown) of the stopper 37, and the pressurizing chamber 11 Inflow to. In the valve open state of the electromagnetic suction valve 3, the valve portion 32 comes into contact with the stopper 37, so that the position of the valve portion 32 in the valve opening direction is restricted. The gap existing between the valve portion 32 and the seated portion 31a in the valve open state of the electromagnetic suction valve 3 is the movable range of the valve portion 32, and this is the valve opening stroke.
[0066]
　After completing the inhalation process, the process moves to the ascending process. At this time, the electromagnetic coil 35 remains in a non-energized state, and no magnetic attraction force acts between the anchor 36 and the magnetic core 39. Then, in the valve portion 32, the urging force in the valve opening direction according to the difference between the urging force of the rod urging spring 34 and the valve urging spring 38, and the fuel flow back from the pressurizing chamber 11 to the low pressure fuel flow path 10a. A force that presses in the valve closing direction due to the fluid force generated at the time of operation works.
[0067]
　In this state, in order for the electromagnetic suction valve 3 to maintain the valve open state, the difference in urging force between the rod urging spring 34 and the valve urging spring 38 is set to be larger than the fluid force. The volume of the pressurizing chamber 11 decreases as the plunger 2 rises. Therefore, the fuel sucked into the pressurizing chamber 11 passes between the valve portion 32 and the seating portion 31a again and is returned to the suction port 31b, so that the pressure inside the pressurizing chamber 11 rises. There is no. This process is called a return process.
[0068]
　In the return step, when a control signal from the ECU 101 (see FIG. 1) is applied to the electromagnetic suction valve 3, a current flows through the electromagnetic coil 35 via the terminal member 40. When a current flows through the electromagnetic coil 35, a magnetic attraction force acts between the magnetic core 39 and the anchor 36, and the anchor 36 (rod 33) is attracted to the magnetic core 39. As a result, the anchor 36 (rod 33) moves in the valve closing direction (direction away from the valve portion 32) against the urging force of the rod urging spring 34.
[0069]
　When the anchor 36 (rod 33) moves in the valve closing direction, the valve portion 32 is released from the urging force in the valve opening direction, and the urging force by the valve urging spring 38 and the flow due to the fuel flowing into the suction passage 10b. It moves in the valve closing direction due to physical strength. Then, when the valve portion 32 comes into contact with the seating portion 31a of the suction valve seat 31 (the valve portion 32 is seated on the seating portion 31a), the electromagnetic suction valve 3 is closed.
[0070]
　After the electromagnetic suction valve 3 is closed, the fuel in the pressurizing chamber 11 is boosted as the plunger 2 rises, and when the pressure exceeds a predetermined pressure, the fuel passes through the discharge valve 8 and the common rail 106 (see FIG. 1). Is discharged to. This process is called a discharge process. That is, the ascending stroke from the lower start point to the upper start point of the plunger 2 consists of a return stroke and a discharge stroke. Then, by controlling the energization timing of the electromagnetic suction valve 3 to the electromagnetic coil 35, the amount of high-pressure fuel discharged can be controlled.
[0071]
　If the timing of energizing the electromagnetic coil 35 is advanced, the ratio of the return stroke in the ascending stroke becomes small and the ratio of the discharging stroke becomes large. As a result, less fuel is returned to the suction passage 10b, and more fuel is discharged at high pressure. On the other hand, if the timing of energizing the electromagnetic coil 35 is delayed, the ratio of the return stroke during the ascending stroke increases and the ratio of the discharge stroke decreases. As a result, more fuel is returned to the suction passage 10b, and less fuel is discharged at high pressure. By controlling the energization timing of the electromagnetic coil 35 in this way, the amount of fuel discharged at high pressure can be controlled to the amount required by the engine (internal combustion engine).
[0072]
2. Summary
　As described above, the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment includes a pump body 1 (pump body), a plunger 2 (plunger), and an electromagnetic suction valve 3 (suction valve). ) And a relief valve 4 (relief valve). The plunger 2 reciprocates in the first chamber 1a (first chamber), which is a columnar space provided in the pump body 1. The electromagnetic suction valve 3 sucks fuel into the pressurizing chamber 11 (pressurizing chamber) formed by the first chamber 1a and the plunger 2. The relief valve 4 opens when the fuel pressure on the downstream side of the pressurizing chamber 11 exceeds a set value, and returns the fuel to the pressurizing chamber 11. The pump body 1 has a second chamber 1b (second chamber) in which the relief valve 4 is arranged, and a communication hole 1e (communication hole) that communicates the first chamber 1a and the second chamber 1b. The diameter of the communication hole 1e is the same as the diameter of the first chamber 1a.
[0073]
　When the pump body 1 is machined with holes such as the first chamber 1a, the second chamber 1b, and the communication hole 1e, unnecessary protrusions (burrs) are generated on the machined surface. If you leave the protrusions (burrs), the dimensions of the holes will be incorrect, and you will not be able to attach the parts, or you will be injured if you touch them, so remove the protrusions (burrs). There is a need to. In the above-described embodiment, since the diameter of the communication hole 1e is the same as the diameter of the first chamber 1a, the communication hole 1e can be easily processed and the protrusions (burrs) can be easily removed. Further, the shape of the pump body 1 can be prevented from becoming complicated. Therefore, the productivity of the pump body 1 and the high-pressure fuel supply pump 100 can be improved, and the cost can be reduced.
[0074]
　Further, since the diameter of the communication hole 1e is the same as the diameter of the first chamber 1a, the fuel easily flows from the relief valve 4 to the pressurizing chamber 11, and the relief performance can be improved. Further, since the relief valve is directly incorporated in the second chamber 1b provided in the pump body 1, the housing (seat member) for storing the parts constituting the relief valve can be omitted, the number of parts can be reduced, and the cost can be reduced. Can be planned.
[0075]
　Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the second chamber 1b (second chamber) is a columnar space, and the diameter of the second chamber 1b is the communication hole 1e (communication hole 1e). It is smaller than the diameter of the communication hole). As a result, the fuel flowing from the relief valve 4 to the pressurizing chamber 11 can easily pass through the communication hole 1e, and the relief performance can be improved.
[0076]
　Further, the communication hole 1e (communication hole) of the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment has a cross section orthogonal to the center line of the second chamber 1b (second chamber), and the second chamber 1b. It has a tapered surface 1f (tapered surface) whose diameter decreases toward. As a result, the fuel that has passed through the relief valve 4 arranged in the second chamber 1b can smoothly return to the pressurizing chamber 11 along the tapered surface 1f.
[0077]
　Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the center line of the communication hole 1e (communication hole) is orthogonal to the center line of the second chamber 1b (second chamber). As a result, the fuel that has passed through the relief valve 4 arranged in the second chamber 1b can be efficiently passed through the communication hole 1e so as not to hinder the improvement of the relief performance. Further, the shape of the pump body 1 can be prevented from becoming complicated, and the productivity of the pump body 1 and the high-pressure fuel supply pump 100 can be improved.
[0078]
　Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the diameter of the communication hole 1e (communication hole) is larger than the outer diameter of the plunger 2 (plunger). As a result, the plunger 2 reciprocating in the pressurizing chamber 11 does not collide with the periphery of the communication hole 1e, and the durability of the plunger 2 can be improved.
[0079]
　Further, the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment is a discharge joint 12 (discharge joint) attached to the pump body 1 (pump body) on the downstream side of the pressurizing chamber 11 (pressurizing chamber). To prepare for. The relief valve 4 (relief valve) is inserted into the second chamber 1b (second chamber) from the discharge joint 12. As a result, the relief valve 4 can be easily arranged in the second chamber 1b, and the workability of the assembly work of the high-pressure fuel supply pump 100 can be improved. Further, it is not necessary to newly provide a hole for making the relief valve 4 into the second chamber 1b in the pump body 1, and the shape of the pump body 1 can be prevented from becoming complicated.
[0080] [0080]
　Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the movement direction of the valve portion 43 (valve portion) in the relief valve 4 (relief valve) is the direction in which the plunger 2 (plunger) reciprocates. Is orthogonal to. As a result, the second chamber 1b for arranging the relief valve 4 can be prevented from extending in the direction in which the plunger 2 reciprocates. As a result, the length of the pump body 1 in the direction in which the plunger 2 reciprocates can be shortened, and the size of the pump body 1 can be reduced.
[0081]
　Further, the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment includes a discharge valve 8 (discharge valve) arranged on the downstream side of the pressurizing chamber 11 (pressurizing chamber). The moving direction of the valve portion 82 (valve portion) in the discharge valve 8 is different from the moving direction of the valve portion 43 (valve portion) in the relief valve 4 (relief valve). The relief valve 4 is arranged at a position higher than the discharge valve 8 in the vertical direction in which the plunger 2 (plunger) reciprocates. As a result, even if a part of the discharge valve 8 and the relief valve 4 overlap in the direction orthogonal to the vertical direction, they can be prevented from interfering with each other, and the space inside the pump body 1 can be effectively utilized. , The size of the pump body 1 can be reduced.
[0082]
　Further, the pump body 1 (pump body) of the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment is formed in a substantially columnar shape, and the center of the first chamber 1a (first chamber) is. It coincides with the center of the pump body 1. The moving direction of the valve portion 82 (valve portion) in the discharge valve 8 (discharge valve) is the first radial direction of the pump body 1. Further, the moving direction of the valve portion 43 (valve portion) in the relief valve 4 (relief valve) is a second radial direction different from the first radial direction of the pump body 1. As a result, the discharge valve 8 and the relief valve 4 can be arranged at positions where they do not overlap each other in the moving direction (vertical direction) of the plunger 2, and the space inside the pump body 1 can be effectively utilized to effectively utilize the space inside the pump body 1. It is possible to reduce the size.
[0083]
　Further, the pump body 1 (pump body) of the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment communicates with the first chamber 1a (first chamber) and has a larger diameter than the first chamber 1a. It has a third room 1c (third room). In the third chamber 1c, a cylinder 6 (cylinder) through which the plunger 2 (plunger) slidably penetrates is arranged. As a result, the end surface of the cylinder 6 can be brought into contact with the step portion between the first chamber 1a and the third chamber 1c, and the cylinder 6 can be prevented from being displaced toward the first chamber 1a. can.
[0084]
　The embodiment of the fuel pump of the present invention has been described above, including its action and effect. However, the fuel pump of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention described in the claims. Further, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations.
[0085]
　For example, in the above-described embodiment, the moving direction of the valve portion 32 in the electromagnetic suction valve 3 is the same as the moving direction of the valve portion 43 in the relief valve 4 (see FIG. 2). However, the moving direction of the valve portion in the relief valve according to the present invention may be different from the moving direction of the valve portion in the electromagnetic suction valve. For example, in the fuel pump according to the present invention, the moving direction of the valve portion in the relief valve, the moving direction of the valve portion in the electromagnetic suction valve, and the moving direction of the valve portion in the discharge valve may all be different.
Code description
[0086]
　1 ... Pump body, 1a ... 1st room, 1b ... 2nd room, 1c ... 3rd room, 1d ... Suction passage, 1e ... Communication hole, 1f ... Tapered surface, 1A ... Center line, 2 ... Plunger, 3 ... Electromagnetic Suction valve, 4 ... Relief valve, 5 ... Suction joint, 6 ... Cylinder, 8 ... Discharge valve, 9 ... Pressure pulsation reduction mechanism, 10 ... Low pressure fuel chamber, 11 ... Pressurization chamber, 12 ... Discharge joint, 31 ... Suction valve Seat, 31a ... Seating section, 31b ... Suction port, 32 ... Valve section, 33 ... Rod, 35 ... Electromagnetic coil, 36 ... Anchor, 37 ... Stopper, 39 ... Magnetic core, 40 ... Terminal member, 42 ... Relief valve holder, 43 ... Valve, 44 ... Seat member, 81 ... Discharge valve seat, 82 ... Valve stopper, 84 ... Discharge valve stopper, 85 ... Plug, 100 ... High pressure fuel supply pump (fuel pump), 101 ... ECU, 102 ... Feed pump , 103 ... Fuel tank, 104 ... Low pressure piping, 105 ... Fuel pressure sensor, 106 ... Common rail, 107 ... Injector
The scope of the claims
[Claim 1]
　A pump body,
　a plunger that reciprocates in a first chamber that is a columnar space provided in the pump body,
　a suction valve that sucks fuel into the first chamber and a pressurizing chamber formed by the plunger, and a suction valve.
　In a fuel pump provided with a relief valve that opens when the fuel pressure on the downstream side of the pressurizing chamber exceeds a set value and returns fuel to the pressurizing chamber, the
　pump body has the relief valve. A 　fuel pump having a second chamber to be arranged and a communication hole communicating the first chamber and the second chamber, and
　the diameter of the communication hole is the same as the diameter of the first chamber .
[Claim 2]
　The fuel pump according to claim 1, 　wherein the second chamber is a columnar space portion, and
　the diameter of the second chamber is smaller than the diameter of the communication hole .
[Claim 3]

　The fuel pump according to claim 2 　, wherein the communication hole has a tapered surface whose diameter decreases toward the second chamber in a cross section orthogonal to the center line of the second chamber .
[Claim 4]

　The fuel pump according to claim 　2, wherein the center line of the communication hole is orthogonal to the center line of the second chamber .
[Claim 5]

　The fuel pump according to claim 1 　, wherein the diameter of the communication hole is larger than the outer diameter of the plunger .
[Claim 6]
　The fuel pump according to claim 1 , further comprising 　a discharge joint attached to the pump body on the downstream side of the pressurizing chamber,
　wherein the relief valve is inserted into the second chamber from the discharge joint .
[Claim 7]

　The fuel pump according to claim 1 　, wherein the moving direction of the valve portion in the relief valve is orthogonal to the direction in which the plunger reciprocates .
[Claim 8]
　A discharge valve arranged on the downstream side of the pressurizing chamber is provided, and
　the moving direction of the valve portion in the discharge valve is different from the moving direction of the valve portion in the
　relief valve, and the plunger reciprocates in the relief valve.
　The fuel pump according to claim 1, which is arranged at a position higher than the discharge valve in the vertical direction, which is the direction .
[Claim 9]
　The pump body is formed in a substantially columnar shape,
　the center of the first chamber coincides with the center of the pump body, and
　the moving direction of the valve portion in the discharge valve is the first radial direction of the pump body.
　The fuel pump according to claim 8 , wherein the moving direction of the valve portion in the relief valve is a second radial direction different from the first radial direction of the pump body .
[Claim 10]
　The pump body communicates with the first chamber and has a third chamber having a diameter larger than that of the first chamber. In
　the third chamber, a cylinder through which the plunger slidably penetrates is arranged.
　The fuel pump according to claim 1.