JP2017031903A - High-pressure fuel supply pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit advancement of cavitation erosion even when a high-pressure fuel supply pump discharges at high-pressure or when biofuel (alcohol, methanol, etc.) or fuel with high-biofuel oil containing-proportion is used.SOLUTION: The high-pressure fuel supply pump includes: a discharge valve for discharging fuel from a compression chamber; and a discharge valve seat on which the discharge valve seats, where a substrate of the discharge valve or discharge valve seat is iron steel material and the surface thereof is formed of a nitrogen martensitic structure in which nitrogen atom is solid-solubilized.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a high-pressure fuel supply pump that pumps fuel to a fuel injection valve of an internal combustion engine, and more particularly, to a high-pressure fuel supply pump that includes a discharge valve provided on the discharge side of a pressurizing chamber.

  In an internal combustion engine such as an automobile, in a direct injection type in which fuel is directly injected into a combustion chamber, a high-pressure fuel supply pump having an electromagnetic intake valve that increases the pressure of the fuel and discharges a desired fuel flow rate is widely used. Yes.

  As this high-pressure fuel supply pump, one described in Japanese Patent Application Laid-Open No. 2012-251447 (Patent Document 1) is known. In the high-pressure fuel supply pump disclosed in Patent Document 1, “the swash plate, the slipper, and the plunger that slide in the lubricating oil in order to make the sliding mechanism parts in the fuel chamber have excellent wear resistance in a harsh environment. And at least one sliding surface that contacts each other of the sliding members of the plunger and cylinder that slide in the fuel and slides through the fuel, from any of the nitrided layer, the carburized and quenched layer, and the carbonitrided layer It is disclosed that such a hardened layer or a hard metal compound layer having high corrosion resistance with respect to the hardened layer is formed.

JP 2003-148294 A

  The intake valve, the discharge valve, or the relief valve is constantly exposed to the intense flow of fuel as the valve is repeatedly opened and closed. Vigorous flow causes the generation of cavities explained by the cavitation phenomenon. When the cavity collapses on the surface of the valve, the valve surface receives the collapse pressure of the cavity and eventually cavitation erosion proceeds. As cavitation erosion progresses and the valve surface is damaged, the valve cannot remain oil tight in the closed state.

  In recent years, the environment surrounding automobiles or in-cylinder injection engine systems has been changing every moment. In particular, regulations regarding heightened awareness of environmental conservation and soot discharged from automobiles will be strengthened in the future. In order to cope with them on the side of the in-cylinder injection engine system, it is necessary that the injector can inject a leaner fuel into the cylinder of the engine. For this purpose, it is necessary to increase the capacity of the pressure that the high-pressure fuel supply pump can discharge. As the discharge pressure increases, the probability of cavitation erosion and the speed of progress increase.

  In recent years, bio-derived biofuels have been produced and distributed as an alternative to conventional mineral oil-derived fuels. There are various forms of bio use in various countries and regions, but there are many examples that are mainly used as a mixed fuel in which mineral oil and bio fuel are mixed. In addition, mineral oil and natural gas-derived alcohol fuels are often used alone or as mixed fuels mixed with conventional mineral oil-derived fuels. In the fuel for gasoline automobiles, the fuel derived from mineral oil is referred to as E0, and the alcohol fuel is referred to as E3, E85, and M15 as follows, for example, depending on the concentration of ethanol or methanol. Here, E3 and E85 are gasoline automobile fuels whose ethanol volume ratio is 3% and 85%. M15 is a fuel for gasoline automobiles in which the volume ratio of methanol is 15%.

  In the test by the present inventor, it can be understood that the time until cavitation erosion occurs differs between E0 and E100. That is, when E100 is used, cavitation erosion occurs at least half the time of E0. When E10, E22, and E85 are used, cavitation erosion occurs at a time between E0 and E100. The length of these times decreases as the ethanol concentration increases. In the future, the mixing ratio of ethanol and other fuels to gasoline automobile fuel is expected to increase. Some countries and regions already use high-concentration ethanol fuel. Under such circumstances, high-pressure fuel supply pumps need countermeasures against cavitation erosion corresponding to fuel containing ethanol.

  The present invention has been made in view of such circumstances, and in a high-pressure fuel supply pump, when the pressure becomes higher, biofuel (alcohol, methanol, etc.), or fuel with a high oil content ratio of biofuel is used. Even when used, it aims to suppress the progress of cavitation erosion.

    In the present invention, in order to solve the above problems, a high-pressure fuel supply pump comprising a discharge valve for discharging fuel from a pressurizing chamber and a discharge valve seat on which the discharge valve is seated, the discharge valve, or the The base material of the discharge valve sheet is a steel material, and the surface thereof is formed of a nitrogen martensite structure in which nitrogen atoms are dissolved.

  According to the present invention, the cavitation erosion progresses even when the pressure of the high-pressure fuel supply pump becomes higher, or when biofuel (alcohol, methanol, etc.) or fuel with a high biofuel oil content is used. Can be suppressed.

1 is a longitudinal sectional view of a high-pressure fuel supply pump according to a first embodiment of the present invention. It is the longitudinal cross-sectional view shown by the cross section different from FIG. 1 of the high-pressure fuel supply pump by 1st Example of this invention, and is sectional drawing which also showed attachment to an engine. 1 is an enlarged longitudinal sectional view of an electromagnetic suction valve of a high-pressure fuel supply pump according to a first embodiment of the present invention, showing a state in which the electromagnetic suction valve is opened. 1 is an enlarged longitudinal sectional view of an electromagnetic intake valve of a high-pressure fuel supply pump according to a first embodiment of the present invention, showing an electromagnetic intake valve in an initial state of closing and a state in which the electromagnetic intake valve is energized. 1 is an enlarged longitudinal sectional view of an electromagnetic suction valve of a high-pressure fuel supply pump according to a first embodiment of the present invention, showing a state in which the electromagnetic suction valve is in a late valve closing state and energization of the electromagnetic suction valve is released. It is a timing chart which shows operation | movement of the plunger of the high pressure fuel supply pump by 1st Example of this invention, and an electromagnetic suction valve. Cavitation test results showing the effect of the configuration of the present invention It is sectional drawing of the electromagnetic suction valve of the high pressure fuel supply pump by 2nd Example of this invention. 1 is an overall configuration diagram schematically showing an example of a fuel supply system including a high-pressure fuel supply pump according to a first embodiment and a second embodiment of the present invention. The relationship between the depth and the concentration of the nitrogen martensite structure when a nitrogen martensite structure is formed on the discharge valve 8b or the discharge valve seat 8a made of stainless steel by nitriding treatment is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, when the position in the vertical direction or the vertical direction is described without particular notice, the vertical direction or the vertical position is defined by the vertical direction or the vertical position on the paper surface of FIG. It does not mean the vertical direction or the vertical position in the state where the supply pump is mounted.

  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 is a main body of a high-pressure fuel supply pump (hereinafter referred to as a high-pressure pump), and mechanisms and components shown in the broken line are 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 the 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 of the high pressure pump. (Suction joint) 10a.

  The fuel that has passed through the suction joint 10a reaches the suction port 31b of the electromagnetic suction valve 300 constituting 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 of the engine, and the reciprocating motion of the plunger 2 sucks fuel from the suction valve 30 part in the lowering process of the plunger 2 and pressurizes the fuel in the ascending process. The fuel is pumped to the common rail 23 to which the pressure sensor 26 is mounted via the discharge valve mechanism 8 having 8b, 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 so that a desired supply fuel pressure is obtained by a signal from the ECU 27 to the electromagnetic suction valve 300.

  The relief valve mechanism 100 is configured to prevent abnormal high pressure. When the pressure rises above the set pressure of the relief valve 100, the relief valve mechanism 100 is opened and the fuel is returned to the pressurizing chamber 11 of the high pressure pump. This prevents the inside of the common rail 23 from becoming an abnormally high pressure state.

  The pump body 1 is further provided with a high-pressure channel 110 that communicates the discharge passage 12 on the downstream side of the discharge valve mechanism 8 and the pressurizing chamber 11, bypassing the discharge valve mechanism 8. The high-pressure channel 110 is provided with a relief valve mechanism 100 having a relief valve 102 that restricts the flow of fuel in only one direction from the discharge passage 12 to the pressurizing chamber 11. The relief valve 102 is pressed against the relief valve seat 101 by a relief spring 105 that generates a pressing force, and when the pressure difference between the inside of the pressurizing chamber 11 and the inside of the high-pressure flow path 110 exceeds a specified pressure, the relief valve 102 is pressed. 102 is set to open from the relief valve seat 101.

  When the common rail 23 becomes an abnormally high pressure due to a failure of the electromagnetic suction valve 300 of the high-pressure pump and the differential pressure between the discharge passage 12 and the pressurizing chamber 11 exceeds the opening pressure of the relief valve 102, the relief valve 102 opens. The fuel having an abnormally high pressure is returned from the high-pressure channel 110 to the pressurizing chamber 11, and the high-pressure section piping such as the common rail 23 is protected.

  The configuration and operation of the high-pressure pump will be described with reference to FIGS.

  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 main body 1 for sealing between the cylinder head 90 and the pump main body 1 to prevent engine oil from leaking to the 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 12. A plurality of communication holes 6b for communicating the annular groove 6a and the pressurizing chamber 11 are provided.

  The cylinder 6 is press-fitted and fixed to the pump main body 1 at the outer diameter portion (outer peripheral portion), and sealed with a cylindrical surface of the press-fitting portion so that fuel pressurized from a gap with the pump main body 1 does not leak to the low pressure side. The cylinder 6 has a small-diameter portion 6 c at the end of the pressurizing chamber, and is fitted into a small-diameter portion 1 a provided in the pump body 1. When the fuel in the pressurizing chamber 11 is pressurized, a force that presses the cylinder 6 toward the low-pressure fuel chamber 10c acts. The small diameter portion 1a and the small diameter portion 6c receive this force to prevent the cylinder 6 from coming out to the low pressure fuel chamber 10c side. The annular surface formed around the small-diameter portion 6c of the cylinder 6 and the annular surface formed around the small-diameter portion 1a of the pump main body 1 are configured by planes, and the respective planes are brought into contact with each other 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 slidable contact with the outer periphery of the plunger 2 in the lower part of the cylinder 6 in the figure, and the fuel in the low pressure chamber 7a is supplied. The structure is such that even when the plunger 2 slides, the fuel can be prevented from leaking outside. 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 damper cover 14 is fixed to the head of the pump body 1. The damper cover 14 is provided with a suction joint 51 and forms a low-pressure fuel suction port 10a. The fuel that has passed through the low-pressure fuel suction port 10a passes through the filter 52 fixed inside the suction joint 51, and reaches the suction port 31b of the electromagnetic suction valve 300 via the pressure pulsation reducing mechanism 9 and the low-pressure fuel flow path 10d. .

  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 suction port 10a from being sucked into the high pressure fuel supply pump by the flow of fuel.

  Since the plunger 2 has the large diameter portion 2a and the small diameter portion 2b, the volume of the annular low-pressure fuel chamber 7a is increased or decreased by the reciprocating motion of the plunger 2. The increase / decrease of the volume is communicated with the low pressure fuel chamber 10 by the fuel passage 1d, so that when the plunger 2 is lowered, the annular low pressure fuel chamber 7a is moved to the low pressure fuel chamber 10, and when the plunger 2 is lifted, A fuel flow is generated into the annular low pressure fuel chamber 7a.

  As a result, the flow rate of fuel into and out of the pump in the pump suction process or return process can be reduced, and the function of reducing pulsation is provided.

  The low pressure fuel chamber 10 is provided with a pressure pulsation reducing mechanism 9 for reducing 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 (suction port 31b) through the suction valve body 30 that is opened again for capacity control, it is returned to the suction passage 10d (suction port 31b). Pressure pulsation occurs in the low pressure fuel chamber 10 due to the fuel. However, the pressure pulsation reducing mechanism 9 provided in the low-pressure fuel chamber 10 is formed of a metal 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 as the metal damper expands and contracts. 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 move back and forth of the mounting bracket 9b. ing.

  A discharge valve mechanism 8 is provided at the outlet of the pressurizing chamber 11. The discharge valve mechanism 8 includes a discharge valve sheet 8a, a discharge valve 8b that contacts and separates from the discharge valve sheet 8a, a discharge valve spring 8c that urges the discharge valve 8b toward the discharge valve sheet 8a, a discharge valve 8b, and a discharge valve sheet 8a. The discharge valve seat 8a and the discharge valve holder 8d are joined by welding at a contact portion 8e to form an integral discharge valve mechanism 8.

  A stepped portion 8f that forms a stopper that restricts the stroke of the discharge valve 8b is provided inside the discharge valve holder 8d.

  In a state where there is no fuel differential pressure in the pressurizing chamber 11 and the fuel discharge port 12, the discharge valve 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 fuel discharge port 12, the discharge valve 8 b opens against the discharge valve spring 8 c, and the fuel in the pressurization chamber 11 is discharged from the fuel discharge port. 12 is discharged to the common rail 23 through a high pressure. When the discharge valve 8b is opened, it comes into contact with the discharge valve stopper 8f, and the stroke is limited. Accordingly, the stroke of the discharge valve 8b is appropriately determined by the discharge valve stopper 8d. As a result, the stroke is too large, and the fuel discharged at high pressure to the fuel discharge port 12 due to the delay in closing the discharge valve 8b can be prevented from flowing back into the pressurizing chamber 11, and the efficiency of the high pressure pump is reduced. Can be suppressed. Further, when the discharge valve 8b repeats opening and closing movements, the discharge valve 8b is guided by the inner peripheral surface of the discharge valve holder 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 process state, the volume of the pressurizing chamber 11 increases and the fuel pressure in the pressurizing chamber 11 decreases. In this step, when the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure in the suction passage 10d, the fuel passes through the suction valve 30 in the open state, and the communication hole 1a provided in the pump body 1 and the cylinder outer peripheral passage. It passes through 6d and flows into the pressurizing chamber 11.

  After the plunger 2 finishes the suction process, the plunger 2 moves to the compression process. Here, the electromagnetic coil 43 remains in a non-energized state, and no magnetic biasing force acts. Therefore, the suction valve 30 remains open by the biasing force of the rod biasing spring 40. The volume of the pressurizing chamber 11 decreases with the compression movement of the plunger 2, but in this state, the fuel once sucked into the pressurizing chamber 11 is returned to the suction passage 10d through the opened suction valve 30 again. Therefore, the pressure in the pressurizing chamber 11 does not increase. This process is called a return process.

  In this state, when a control signal from the ECU 27 is applied to the electromagnetic intake valve 300, an electric current flows through the electromagnetic coil 43, and the rod 35 moves away from the intake valve 30 due to the magnetic urging force, thereby energizing the intake valve. The suction valve 30 is closed by the urging force of the spring 33 and the fluid force caused by the fuel flowing into the suction passage 10d. 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 process is called a discharge process.

  That is, the compression process of the plunger 2 (the ascending process from the lower start point to the upper start point) includes a return process and a discharge process. 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 process in the compression process is small and the ratio of the discharge process 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 timing of energization is delayed, the ratio of the return process in the compression process is large and the ratio of the discharge process 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.

  Here, the electromagnetic intake valve of the present embodiment will be described in detail with reference to cross-sectional views of FIGS. 3 to 5 and a timing chart of FIG.

  FIG. 3 is an enlarged view of the electromagnetic suction valve 300, showing a state in which the electromagnetic coil 43 is not energized and in a state where the pressure in the pressurizing chamber 11 is low (pressure fed by the feed pump 21). . In this state, an inhalation process and a return process are performed. FIG. 4 is an enlarged view of the electromagnetic suction valve 300, in which the electromagnetic coil 43 is energized, the anchor 36, which is a movable part, comes into contact with the second core 39 by electromagnetic suction force, and the suction valve 30 is closed. . FIG. 5 is an enlarged view of the electromagnetic suction valve 300, and shows a non-energized state in which the energization of the electromagnetic coil 43 is released when the suction valve is closed after the pressure in the pump chamber has increased sufficiently.

  The intake valve section includes an intake valve 30, an intake valve seat 31, an intake valve stopper 32, an intake valve biasing spring 33, and an intake valve holder 34.

  The suction valve seat 31 has a cylindrical shape, and has a seat portion 31a in the axial direction on the inner peripheral side, and two or more suction passage portions 31b radially around the axis of the cylinder. Press-fitted and held.

  The suction valve holder 34 has claws in two or more directions radially, and the outer peripheral side of the claws is fitted and held coaxially on the inner peripheral side of the suction valve seat 31. Further, a suction valve stopper 32 having a cylindrical shape and having a collar shape at one end is press-fitted and held on the inner peripheral cylindrical surface of the suction valve holder 34.

  The suction valve biasing spring 33 is provided on the inner peripheral side of the suction valve stopper 32, and a part of the suction valve biasing spring 33 is disposed in the small diameter portion 32 c for stabilizing one end of the spring 33 coaxially. The suction valve 30 is configured such that a suction valve biasing spring 33 is fitted to the valve guide portion 30b between the suction valve seat portion 31a and the suction valve stopper 32. The suction valve urging spring 33 is a compression coil spring and is installed so that the urging force acts in a direction in which the suction valve 30 is pressed against the suction valve seat portion 31a. It is not limited to the compression coil spring, and any form may be used as long as it can obtain an urging force, and a leaf spring having an urging force integrated with the suction valve may be used.

  By configuring the suction valve portion in this way, in the pump suction process, the fuel that has passed through the suction passage 31b and entered the interior passes between the suction valve 30 and the seat portion 31a, and the outer periphery of the suction valve 30 The fuel flows into the pump chamber (pressurizing chamber) 11 through the passages of the pump body 1 and the cylinder 6 through the side and the claw of the suction valve holder 34. In the discharge process of the pump, the discharge valve 30 is in contact with the suction valve seat portion 31a to perform a check valve function for preventing the reverse flow of fuel to the inlet side.

  In order to smooth the movement of the suction valve 30, a passage 32 a is provided in order to release the hydraulic pressure on the inner peripheral side of the suction valve stopper 32 according to the movement of the suction valve 30.

  The amount of axial movement 30e of the intake valve 30 is limited by the intake valve stopper 32. This is because if the amount of movement is too large, the reverse flow rate increases due to a response delay when the intake valve 30 is closed, and the performance as a pump decreases. The movement amount can be regulated by the axial dimensions and the press-fitting positions of the suction valve seat 31a, the suction valve 30 and the suction valve stopper 32.

  The suction valve stopper 32 is provided with an annular protrusion 32b to reduce the contact area with the suction valve stopper 32 in a state where the suction valve 32 is opened. This is because the intake valve 32 is likely to be separated from the intake valve stopper 32 during the transition from the open state to the closed state, that is, the valve closing response is improved. When there is no annular protrusion 32b, that is, when the contact area is large, a large squeeze force acts between the intake valve 30 and the intake valve stopper 32, and the intake valve 30 is difficult to separate from the intake valve stopper 32.

  The suction valve 30, the suction valve seat 31, and the suction valve stopper 32 are made of a material obtained by heat-treating martensitic stainless steel having high strength, high hardness, and excellent corrosion resistance in order to repeatedly collide with each other. The suction valve spring 33 and the suction valve holder 34 are made of austenitic stainless steel in consideration of corrosion resistance.

  Next, the solenoid mechanism will be described. The solenoid mechanism portion includes a rod 35 that is a movable portion, an anchor 36, a spring seat member 37 that is a fixed portion, a first core 38, a second core 39, a rod biasing spring 40, and an anchor biasing spring 41.

  The rod 35 and the anchor 36 which are movable parts are configured as separate members. The rod 35 is slidably held in the axial direction on the inner peripheral side of the spring seat member 37, and the outer peripheral side of the anchor 36 is slidably held on the inner peripheral side of the first core 38. That is, both the rod 35 and the anchor 36 are configured to be slidable in the axial direction within a geometrically regulated range.

  The anchor 36 has one or more through holes 36a penetrating in the axial direction of the component in order to move smoothly and freely in the axial direction in the fuel, and eliminates the restriction of movement due to the pressure difference before and after the anchor as much as possible. The spring seat member 37 is inserted in the radial direction on the inner peripheral side of the hole into which the suction valve of the pump body 1 is inserted, and in the axial direction, is abutted against one end portion of the suction valve seat 31. It is set as the structure arrange | positioned in the form inserted | pinched between the 1st core 38 and the pump main body 1 which are weld-fixed to. Similarly to the anchor 36, the spring seat member 37 is provided with a through-hole 37a penetrating in the axial direction so that the anchor can move freely and smoothly so that the pressure of the fuel chamber on the anchor side does not hinder the movement of the anchor. It is configured.

  The first core 38 has a thin cylindrical shape on the side 38b opposite to the portion to be welded to the pump body, and is fixed by welding in such a manner that the second core 39 is inserted on the inner peripheral side thereof. A rod biasing spring 40 is disposed on the inner peripheral side of the second core 39 with the small diameter portion 39a as a guide, the tip of the rod 35 contacts the suction valve 30, and the suction valve 30 is pulled away from the suction valve seat portion 31a. That is, an urging force is applied in the opening direction of the intake valve. That is, the intake valve 30 is configured as a separate body from the rod 35 and is configured to be restricted from moving in the valve closing direction by contacting one end of the rod 35. The second core 39 is formed with a magnetic attraction surface 39 a that faces the magnetic attraction surface 36 c of the anchor 36. The magnetic attraction surface 39a of the second core 39 and the magnetic attraction surface 36c of the anchor 36 are parallel to each other, and a gap indicated by reference numeral 36e is provided between the two when the valve is in an open state. By doing so, a magnetic attractive force acts between the two companies, and the anchor 36 is attracted to the second core 39 side.

  The anchor biasing spring 41 applies a biasing force to the anchor 36 in the direction of the rod collar 35a while inserting one end into a cylindrical rod insertion portion 37c provided on the center side of the spring seat member 37 and maintaining the same axis. It is arranged. A rod insertion hole 37b is formed at the center of the rod insertion portion 37c, and the rod 35 is inserted through the rod insertion hole 37b. The rod collar portion 35a restricts relative displacement of the rod 35 in the valve opening direction with respect to the anchor 36. That is, when the rod 35 is relatively displaced in the valve opening direction with respect to the anchor 36, an engaging portion that engages with the anchor 36 and restricts the relative displacement is configured. The rod 35 is not in contact with the rod insertion hole 37b, and a gap is provided between the outer peripheral surface of the rod 35 and the inner peripheral surface of the rod insertion hole 37b.

  The movement amount 36e of the anchor 36 is set larger than the movement amount 30e of the suction valve 30. This is because the intake valve 30 is surely closed.

  Since the rod 35 slides with the anchor 36 and the rod 35 repeatedly collides with the suction valve 30, martensitic stainless steel subjected to heat treatment is used in consideration of hardness and corrosion resistance. The anchor 36 and the second core 39 are made of magnetic stainless steel to form a magnetic circuit, and the respective collision surfaces of the anchor 36 and the second core are subjected to a surface treatment for improving the hardness. Further, the outer peripheral surface of the anchor 36 and the inner peripheral surface of the first core 38 may be subjected to a surface treatment in order to improve hardness and corrosion resistance. The surface treatment includes hard Cr plating, but is not limited thereto. Austenitic stainless steel is used for the rod biasing spring 40 and the anchor biasing spring 41 in consideration of corrosion resistance.

  The intake valve portion is provided with one spring, and the solenoid mechanism portion is provided with two springs, so that the electromagnetic intake valve 300 is configured with three springs. That is, the electromagnetic suction valve 300 includes a suction valve biasing spring 33 configured as a suction valve portion, a rod biasing spring and an anchor biasing spring configured as a solenoid mechanism portion. In this embodiment, any spring uses a coil spring, but any spring can be used as long as it can obtain an urging force.

  Next, the configuration of the coil portion will be described. The coil portion includes a first yoke 42, an electromagnetic coil 43, a second yoke 44, a bobbin 45, a terminal 46, and a connector 47. A coil 43 in which a copper wire is wound around a bobbin 45 is disposed so as to be surrounded by a first yoke 42 and a second yoke 44, and is molded and fixed integrally with a connector 47 that is a resin member. One end of each of the two terminals 46 is connected to both ends of the copper wire of the coil so as to be energized. The terminal 46 is molded integrally with the connector 47, and the other end is connected to the engine control unit side. The coil portion is fixed by press-fitting a hole at the center of the first yoke 42 into the first core 38. At that time, the inner diameter side of the second yoke 44 is in contact with the second core 39 or close to the second core 39 with a slight clearance.

  Both the first yoke 42 and the second yoke 44 are made of a magnetic stainless material in order to form a magnetic circuit and in consideration of corrosion resistance, and the bobbin 45 and the connector 47 are made of high strength in consideration of strength characteristics and heat resistance characteristics. It is constructed using a strong heat-resistant resin. The coil 43 is made of copper, and the terminal 46 is made of brass plated with metal.

  By configuring the solenoid mechanism portion and the coil portion as described above, the first core 38, the first yoke 42, the second yoke 44, the second core 39, and the anchor 36 are used as shown by the arrows in FIG. When a magnetic circuit is formed and a current is applied to the coil, an electromagnetic force is generated between the second core 39 and the anchor 36, and a force that pulls the anchor 36 toward the second core 39 is generated. In the first core 38, the second core 39 and the anchor 36 face each other in the axial direction where the attractive force is generated, and the magnetic resistance is increased by making the axial portion as thin as possible (thin cylindrical shape). Since it passes between the two cores 39 and the anchor 36, an electromagnetic force can be obtained efficiently. In the thin cylindrical portion 38b, an annular groove may be formed in the axial portion where the second core 39 and the anchor 36 face each other, and the thickness may be further reduced to increase the magnetic resistance.

  When the electromagnetic force exceeds the valve opening biasing force f1 obtained by subtracting the biasing force of the anchor biasing spring 41 and the biasing force of the suction valve biasing spring 33 from the biasing force of the rod biasing spring 40, the anchor which is a movable part The movement in which 36 is attracted to the second core 39 together with the rod 35, and the second core 39 and the anchor 36 are brought into contact with each other, and the contact can be continued.

  Hereinafter, the operation and the advantages of the present embodiment will be described in detail with reference to the timing charts of FIGS.

≪Inhalation process≫
When the plunger 2 starts to descend from the top dead center, the pressure in the pressurizing chamber 11 suddenly decreases from a high pressure state of, for example, a 20 MPa level, and the rod 35, the anchor 36 and the suction valve 30 are sucked by the aforementioned force f1. The movement starts in the valve opening direction of the valve 30. When the intake valve 30 is opened, the fuel that has flowed from the passage 31 b of the intake valve seat 31 to the inner diameter side of the intake valve seat 31 starts to be sucked into the pressurizing chamber 11.

  The suction valve 30 collides with the suction valve stopper 32, and the suction valve 30 stops at that position. Similarly, the rod 35 also stops at a position where the tip comes into contact with the intake valve 30 (a plunger rod opening position in FIG. 6).

  The anchor 36 also moves in the valve opening direction of the suction valve 30 at the same speed as the rod 35, but after the rod 35 comes into contact with the suction valve 30 and stops, it tries to continue to move with inertial force. The movement due to the inertial force is a portion shown in FIG. However, the anchor urging spring 41 overcomes the inertial force, the anchor 36 moves again in the direction approaching the second core 39, and contacts the rod collar portion 35a in such a manner that the anchor 36 is pressed against it (in FIG. 6). It can be stopped at the anchor opening position). A state showing the positions of the anchor 36, the rod 35, and the suction valve 30 at the time of stopping is the state shown in FIG.

  6A and 6B, the rod 35 and the anchor 36 are completely separated from each other. However, the rod 35 and the anchor 36 may be in contact with each other. In other words, the load acting on the contact portion between the rod collar portion 35a and the anchor 36 decreases after the movement of the rod 35 stops, and when it becomes zero, the anchor 36 starts to separate from the rod 35, but does not become zero and is slightly The urging force of the anchor urging spring 41 may be set so as to leave the load.

  When the suction valve 30 collides with the suction valve stopper 32, a problem of abnormal noise that becomes an important characteristic as a product occurs. The magnitude of the noise is affected by the magnitude of the energy at the time of the collision. However, since the rod 35 and the anchor 36 are configured separately, the energy that collides with the suction valve stopper 32 is generated only by the mass of the suction valve 30 and the mass of the rod 35. That is, since the mass of the anchor 36 does not contribute to the collision energy, the size of the noise can be reduced by configuring the rod 35 and the anchor 36 separately.

  The holding method (supporting method) in the radial direction of the anchor 36 includes a method of holding with a clearance between the inner diameter of the anchor 36 and the outer diameter of the rod 35, and a clearance between the outer diameter of the anchor 36 and the inner peripheral surface of the first core 38. There is a method to hold in. In the present embodiment, the radial position of the anchor 36 is maintained by using the outer diameter of the anchor 36 and the inner peripheral surface of the first core 38 as sliding surfaces.

  After the intake valve 30 is opened, the plunger 2 further descends and reaches the bottom dead center. During this time, fuel continues to flow into the pressurizing chamber 11, and this process is an intake process.

≪Return process≫
The plunger 2 lowered to the bottom dead center enters the ascending process. The suction valve 30 remains stopped in the open state by the electromagnetic force exceeding f1, and the direction of the fluid passing through the suction valve 30 is reversed. That is, in the suction process, the fuel flows into the pressurizing chamber 11 from the suction valve seat passage 31b. On the other hand, the fuel is returned from the pressurizing chamber 11 toward the suction valve seat passage 31b at the time of the rising process. This process is called a return process.

≪Transition state from return process to discharge process≫
A current is applied to the electromagnetic coil 43 at a time earlier than the desired discharge time considering the generation delay of the electromagnetic force and the valve closing delay of the suction valve 30, and the magnetic attraction force between the anchor 36 and the second core 39. Work. It is necessary to apply a current having a magnitude necessary to generate a magnetic attractive force that overcomes the force f1. When this magnetic attraction force overcomes the force f1, the anchor 36 starts moving toward the second core 39. When the outer peripheral surface of the anchor 36 slides and moves on the inner peripheral surface of the first core 38, the rod 35 that is in contact with the collar portion 35a in the axial direction also moves, and the intake valve 30 is moved to the intake valve biasing spring. The valve closes under the force of 33. At this time, the hydrodynamic force, mainly the static pressure due to the flow rate of the fuel passing through the seat portion from the pressurizing chamber 11 side, decreases.

  As described above, in the present embodiment, the anchor 36 is configured to move in the axial direction of the rod 35 with the inner peripheral surface 38a of the first core 38 serving as a guide surface. For this reason, the distance between the outer peripheral surface of the anchor 36 and the inner peripheral surface 38a of the first core 38 is very small, and a very large fluid resistance is given to the fuel flow that attempts to flow through the gap. ing.

  In the present embodiment, the anchor 36 and the first core 38 are configured to slide in contact with each other, and the rod 35 is configured to slide in contact with the through hole 36 b of the anchor 36. That is, the rod 35 is guided by the through hole 36 b of the anchor 36 and is configured to be relatively displaceable with the anchor 36. For this reason, a gap is provided between the inner circumferential surface of the rod insertion hole 37 b of the spring seat member 37 and the outer circumferential surface of the rod 35.

  The suction valve 30 that has started to move is brought into a closed state by colliding with the seat portion 31a and stopping. When the valve is closed, the in-cylinder pressure rapidly increases, so that the suction valve 30 is firmly pressed by the in-cylinder pressure in the valve closing direction with a force much larger than the force f1 and starts to maintain the valve closed state.

  The anchor 36 also collides with the second core 39 and stops. The rod 35 continues to move with the inertial force even after the anchor 36 stops, but the urging force of the rod urging spring 40 overcomes the inertial force and is pushed back so that the collar portion 35a can return to a position where it comes into contact with the anchor 36.

  When the anchor 36 collides with the second core 39, a problem of abnormal noise that becomes an important characteristic as a product occurs. This abnormal noise is larger than the magnitude of the abnormal noise with which the suction valve 30 and the suction valve stopper 32 collide, and becomes a larger problem. The magnitude of the noise is affected by the magnitude of the energy at the time of the collision. However, since the rod 35 and the anchor 36 are configured separately, the energy that collides with the second core 39 is generated only by the mass of the anchor 36. That is, since the mass of the rod 35 does not contribute to the collision energy, the size of the noise can be reduced by configuring the rod 35 and the anchor 36 separately.

  Once the anchor 36 has contacted the second core 39, a sufficient magnetic attraction force is generated by the contact, and therefore, a small current value can be obtained only for maintaining contact.

  Here, the problem of erosion that may occur in the solenoid mechanism will be described.

  When a flow path in which fuel flows is formed between the anchor 36 and the first core 38, when the current is applied to the coil and the anchor 36 is pulled toward the second core 39, the anchor 36 and the second core 39 As the volume of the space between them rapidly shrinks, the fluid (fuel) in that space loses its destination, is swept away toward the outer periphery of the anchor 36 with a fast flow, and collides with the thin portion of the first core 38. To do. There is a concern that erosion may occur in the thin cylindrical portion 38b of the first core 38 due to the energy of the collision of the fuel flow. In addition, the pushed fluid passes through the outer periphery of the anchor 36 and flows to the spring seat member 37 side. At this time, since the flow path on the outer peripheral side of the anchor 36 is narrow, the flow velocity increases, and cavitation occurs due to a rapid decrease in static pressure, and erosion due to cavitation may occur in the thin portion of the first core 38. There is.

  This cavitation erosion can be solved in the present embodiment for the following reason.

  In the present embodiment, since the outer periphery of the anchor 36 and the inner peripheral portion of the first core 38 constitute a sliding portion, the clearance is about 5 to 10 μm in diameter difference. On the other hand, one or more axial through holes (through holes) 36 a are provided on the center side of the anchor 36. The through hole 36a penetrates the anchor 36 in the central axis direction (axial direction of the rod 35), and a space (fuel chamber) on the second core 39 side and a space (fuel chamber) on the spring seat member 37 side with respect to the anchor 36. The fuel passage which communicates is constituted. When the anchor 36 is drawn toward the second core 39 side, most of the fluid in the space between the anchor 36 and the second core 39 does not pass through the narrow passage on the outer peripheral side of the anchor 36 but passes through the through hole 36a. Thus, the fuel chamber moves to the fuel chamber formed between the anchor 36 and the spring seat member 37. By comprising in this way, the erosion of the thin part 38b of the 1st core 38 can be avoided.

  Even when the anchor 36 and the rod 35 are integrally formed, the above problem can be solved by optimizing the capacity of the through hole 36a of the anchor 36. The through hole 36a of the anchor 36 only needs to be configured such that its fluid resistance is smaller than the fluid resistance in the gap between the outer peripheral surface of the anchor 36 and the inner peripheral surface of the first core 38. And the through-hole 36a of the anchor 36 should just be provided inward (center side) of radial direction rather than the outer peripheral surface of the anchor 36. FIG. For example, a groove may be provided on the inner peripheral surface of the center hole 36b through which the rod 35 is inserted, with an interval in the circumferential direction. Alternatively, the through hole 36a of the anchor 36 may be configured such that the outer peripheral surface of the rod 35 does not slide. In this case, the rod 35 may slide on the inner peripheral surface of the rod insertion hole 37 b of the spring seat member 37. That is, the spring seat member 37 may be configured as a rod guide.

  In the case where the anchor 36 and the rod 35 are integrally configured, a force is applied to the coil 43 to cause the anchor 36 to move to the second core 39 when the engine is rotating at a high speed, that is, when the ascending speed of the plunger 2 is high. Furthermore, the force that closes the suction valve 30 by the fluid having a very high speed is increased as an additional imparting force, and the rod 35 and the anchor 36 approach the second core 39 rapidly, so that the speed at which the fluid in the space is pushed out is increased. It gets bigger. Therefore, the problem of erosion can be solved by optimizing the design such as increasing the capacity of the through hole 36a of the anchor 36, that is, increasing the number of holes or expanding the hole diameter.

  As described above, there are problems that the anchor 36 and the rod 35 are separately formed. However, there are problems that the desired magnetic attraction force cannot be obtained, abnormal noise, and functional deterioration. It becomes possible to get rid of.

≪Discharge process≫
Immediately after the return of the plunger 2 from the bottom dead center to the ascending process and when the current is applied to the coil 43 at the desired timing and the suction valve 30 is closed, the pressure in the pressurizing chamber 11 rapidly increases, It becomes a discharge process. After the discharging process, it is desirable to reduce the power applied to the coil 43 from the viewpoint of power saving, so the current applied to the coil is cut. The electromagnetic force is no longer applied, and the anchor 36 and the rod 35 move away from the second core 39 by the resultant force of the rod biasing spring 40 and the anchor biasing spring 41. However, since the intake valve 30 is in the closed position with a strong closing force, the rod 35 stops at the position where it collides with the closed intake valve 30.

  The rod 35 and the anchor 36 start to move at the same time after the current is cut off, but the anchor 36 is sucked by inertia force even after the rod 35 is stopped in a state where the tip of the rod 35 and the suction valve 30 in the closed state are in contact with each other. It tries to continue moving in the direction of the valve 30. It is the state of B of FIG. However, since the anchor biasing spring 41 overcomes the inertial force and applies a biasing force in the direction of the second core 39 to the anchor 36, the anchor 36 stops in a state where it is in contact with the collar portion 35a of the rod 35 (the state shown in FIG. 5). can do.

  In this way, the discharge process for discharging the fuel is performed, and immediately before the next intake process, the intake valve 30, the rod 35 and the anchor 36 are in the state shown in FIG.

  When the plunger 2 reaches the top dead center, the discharge process is finished and the suction process is started again.

  Thus, the fuel guided to the low pressure fuel suction port 10a is pressurized to a high pressure by the reciprocation of the plunger 2 in the pressurizing chamber 11 of the pump body 1, and is pumped from the fuel discharge port 12 to the common rail 23. Therefore, it is possible to provide a high pressure pump suitable for the above.

  In addition, as described above, in recent years, the high-pressure fuel supply pump has been required to have a higher pressure. For example, a high-pressure fuel supply pump having a target discharge pressure of 25 MPa or more may be required. In this way, when the target discharge pressure becomes very high, or when biofuel (alcohol, methanol, etc.) or fuel with a high biofuel content is used for the high-pressure fuel supply pump, erosion caused by cavitation Is a problem. Therefore, it is necessary to suppress the progress of this cavitation erosion, to lower the probability of occurrence of cavitation erosion, or to increase the time until cavitation erosion occurs. In this embodiment, since it has been found that cavitation erosion occurs particularly at the location where the valve seat and the valve body contact, this is suppressed.

  More specifically, both the discharge valve 8b and the discharge valve seat 8a, or at least one base material, is a steel material, and the surface thereof is formed of a nitrogen martensite structure in which nitrogen atoms are dissolved. That is, a surface modification process is performed in which nitrogen martensite is formed on the surface of both or at least one of the discharge valve 8b and the discharge valve seat 8a. The nitrogen martensite structure present on at least one surface of both the discharge valve 8b and the discharge valve seat 8a has a lattice constant of a lattice composed of Fe and N of 0.286 to 0.3 mm, and nitrogen. The concentration is from 0.14% to 3% or less.

Although the discharge valve 8b and the discharge valve seat 8a have been described here, the relief valve 100 and the relief valve seat 101 may similarly cause cavitation erosion. Therefore, both or one of the relief valve 100 and the relief valve seat 101 may be formed of a nitrogen martensite structure in which nitrogen atoms are dissolved. Alternatively, a nitrogen martensite structure may be formed on the surfaces of the suction valve 30 and the suction valve seat 31.
As a method for forming a nitrogen martensite structure in these parts, a surface modification treatment called a nitriding treatment is optimal. The nitriding treatment is different from the nitriding treatment and is usually performed at 800 ° C. or higher. The nitriding treatment is generally performed at 400 to 600 ° C. The reason for heat treatment at 800 ° C. or higher is to form a nitrogen martensite structure by heating the steel material to 800 ° C. or higher and maintaining it in the austenite phase, and then dissolving nitrogen in the steel material. To dissolve nitrogen, a catalytic reaction is used when ammonia gas and ammonia come into contact with iron. The chemical change of ammonia by the catalytic reaction is expressed by the following formula.
NH3 → 1 / 2N2 + 3 / 2H2
Moreover, after making nitrogen dissolve into the steel material surface of the state of an austenite phase, it quenches with gas like a normal hardening operation. If deformation of the part shape does not become a problem, it may be cooled rapidly with oil cooling. In this example, after applying the above-described process for forming a nitrogen martensite structure to a discharge valve, the contact area between the valve body and the valve seat is increased by using emery paper of # 1000 or more, or diamond particles having a diameter of 3 μm or less. Polished.

  The above-described discharge valve 8b and discharge valve seat 8a having a nitrogen martensite structure and having a finished surface were incorporated into a high-pressure fuel pump to confirm whether cavitation erosion occurred. Confirm that at least the amount of cavitation erosion is the same or less than that before application compared to steel parts that do not form a nitrogen martensite structure (discharge valve, discharge valve seat). did. However, the effect can also be obtained by performing the nitriding treatment of this embodiment on only one of the discharge valve 8b and the discharge valve seat 8a. If only one is used, the production efficiency can be improved and the production cost can be reduced. In particular, in the present embodiment, since the purpose is to suppress cavitation in the seat portion, the nitriding of the present embodiment is performed not only on the seat portion and the valve body, but only on the discharge valve seat 8a, the relief valve seat 101, or the suction valve seat. It is desirable to perform treatment to form a nitrogen martensite structure on the surface.

  FIG. 10 shows the relationship between the depth and the concentration of the nitrogen martensite structure when the nitrogen martensite structure is formed on the discharge valve 8b or the discharge valve sheet 8a made of stainless steel by the nitriding treatment of this embodiment. The nitriding treatment of this embodiment forms nitrogen martensite by solid solution of nitrogen atoms, and nitrogen martensite is hard and tough like carbon martensite. And although it is not zero, nitrogen is hardly formed. As shown in FIG. 10, the surface of the nitrogen martensite formed by this example has an N concentration of 0.1% to 1% within a depth of 200 μm, which is lower than the nitriding treatment. On the other hand, the nitriding process is a process for forming nitrides such as Fe3N and Fe4N. Nitride is hard but brittle, so its cavitation resistance is not good. Further, the N concentration is 5 to 20%.

  FIG. 7 shows the results of an experiment conducted in order to quantitatively show the degree of resistance to cavitation erosion of a material and / or its configuration against cavitation erosion resistance according to the present invention. The vertical axis represents the amount of cavitation erosion, and the horizontal axis represents the time of cavitation. The test was performed with water. Gasoline or biofuel is applied to the high-pressure fuel supply pump of this embodiment, but in another verification, cavitation erosion with water, gasoline, ethanol corresponding to biofuel is the same phenomenon, It has been confirmed that even if water is used instead, the result of comparison of material strength does not change.

  As a result of the experiment, as shown in FIG. 7, in SUS420J2 formed by quenching only and SUS420J2 formed with a nitrogen martensite structure on the surface, the former has a period of almost no mass loss called a latent period due to cavitation erosion phenomenon, The latter was 75 minutes. In the high-pressure fuel supply pump, if cavitation erosion occurs after the incubation period, the oil tightness cannot be maintained. Therefore, even if the phenomenon of cavitation erosion occurs, it must be kept within the incubation period. Thus, the criterion for anti-cavitation erosion material in high pressure fuel supply pumps is the length of the incubation period.

  As described above, a nitrogen martensite structure is formed on the surface, and SUS420J2 has a longer incubation period of the cavitation erosion phenomenon than SUS420J2 which is only quenched. Therefore, in the actual high-pressure fuel supply pump shown above, the reason why the amount of cavitation erosion generated in the pump to which the present invention is applied is the same or less is presumed that the configuration to which the present invention is applied works. The

  In the high-pressure fuel supply pump of the present embodiment, a material in which cavitation erosion occurs or progresses slowly is applied to the portion where the liquid flows, so that the fuel pressure and flow rate can be increased. Even when alcohol fuel is used, long-term reliability can be secured in the same manner as when fuel derived from mineral oil is used.

  FIG. 9 shows another embodiment of the intake valve portion. This is a structure that does not have an anchor biasing spring 41 that applies a biasing force to the anchor 36. The configuration other than the anchor urging spring 41 is the same as that of the first embodiment. As in the first embodiment, the outer periphery of the anchor 36 is held by the inner periphery of the first core 38 and exhibits the same operation and effect as the electromagnetic suction valve 300 shown in the first embodiment.

  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 intake port, 11 ... Pressurization chamber, 12 ... Fuel discharge port, DESCRIPTION OF SYMBOLS 13 ... Plunger seal, 30 ... Suction valve, 31 ... Suction valve seat, 33 ... Suction valve spring, 35 ... Rod, 36 ... Anchor, 38 ... First core, 38b ... Thin core shape of the first core, 39 ... Second Core: 40 ... Rod biasing spring, 41 ... Anchor biasing spring, 43 ... Electromagnetic coil, 300 ... Electromagnetic suction valve.

Claims (6)

A discharge valve for discharging fuel from the pressurizing chamber;
In a high-pressure fuel supply pump comprising a discharge valve seat on which the discharge valve is seated,
A base material of the discharge valve or the discharge valve seat is a steel material, and a surface thereof is formed of a nitrogen martensite structure in which nitrogen atoms are solid-dissolved. The high-pressure fuel supply pump according to claim 1,
The nitrogen martensite structure present on the surface of the discharge valve or the discharge valve seat has a lattice constant of 0.286 to 0.3 mm in a lattice composed of Fe and N constituting the nitrogen martensite structure. A high-pressure fuel supply pump characterized by being 14% to 3% or less. The high-pressure fuel supply pump according to claim 1,
The discharge valve or the surface of the discharge valve seat is formed of a nitrogen martensite structure in which nitrogen atoms are solid-dissolved by nitriding treatment. The high-pressure fuel supply pump according to claim 1,
Of the discharge valve seat and the discharge valve, only the surface of the discharge valve seat is formed of a nitrogen martensite structure in which nitrogen atoms are solid-dissolved. The high-pressure fuel supply pump according to claim 1,
A relief valve that opens when the pressure on the discharge side exceeds the set pressure;
A relief valve seat against which the relief valve is pressed,
Of the relief valve seat and the relief valve, only the surface of the relief valve seat is formed of a nitrogen martensite structure in which nitrogen atoms are solid-dissolved. The high-pressure fuel supply pump according to claim 1,
The nitrogen martensite surface has a N concentration of 0.1% to 1% within a depth of 200 μm.

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