JP2019100268A - Fuel supply pump - Google Patents

Abstract

To provide a high pressure pump that satisfies reliability inexpensively.SOLUTION: A fuel supply pump includes: a plunger reciprocating to compress fuel in a compression chamber; and a retainer attached to the plunger to urge the plunger on an opposite side to the compression chamber with urging force of the spring. The retainer is formed of a carbon steel that has been subjected to carburizing and quenching.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a fuel supply pump for an internal combustion engine of a motor vehicle.

  The fuel is pressurized by the plunger 2 which converts the rotational movement of the cam 93 provided on the camshaft for driving the intake valve or exhaust valve of the engine into a reciprocating movement, but as in the case of JP-A 2017-66956 In general, a retainer 15 that receives a spring 4 that always biases the cam 93 is fixed to the tip. (See Figure 1)

JP, 2017-66956, A

  In recent years, the high pressure fuel pump is required to have a higher pressure, such as a discharge pressure of 30 MPa or more. Therefore, since the biasing force of the spring for biasing the plunger is also increased accordingly, a large stress is generated in the retainer 15 for retaining the plunger 2. In particular, the retainer 15 repeatedly receives the fluctuating load of the spring 4 by the reciprocating motion of the plunger 2. Therefore, an object of the present invention is to provide a fuel supply pump provided with a retainer having a corresponding fatigue strength.

  In order to solve the above-mentioned problems, in the present invention, a plunger for pressurizing the fuel in the pressurizing chamber by reciprocating motion and the plunger attached to the plunger urge the plunger to the opposite side to the pressurizing chamber by the biasing force of the spring. A fuel supply pump comprising: a retainer; and the retainer is formed of carburized and hardened carbon steel.

  ADVANTAGE OF THE INVENTION According to this invention, manufacturing cost can be held down, satisfying required fatigue strength. Other configurations, operations and effects of the present invention will be described in the following embodiments.

FIG. 1 is an overall cross-sectional view showing a fuel supply pump according to a first embodiment of the present invention, cut in the axial direction of a plunger. The fuel supply pump of the first embodiment according to the present invention is an overall cross-sectional view cut in a direction perpendicular to the axial direction of the plunger, and is a cross-sectional view at the fuel inlet axis center and the discharge port axis center. FIG. 6 is an overall cross-sectional view of an angle different from that of FIG. 1 of the fuel supply pump of the first embodiment according to the present invention, and a cross-sectional view at the suction joint axial center. It is the figure which expanded the longitudinal cross-sectional view of the electromagnetic suction valve mechanism of the fuel supply pump of 1st Example which concerns on this invention. FIG. 1 is a view showing the overall configuration of a direct injection engine system including a fuel supply pump according to the present invention. It is a figure which shows hardness distribution of the retainer carburized and hardened. It is the graph which showed the relationship between the ratio of the base material hardness range of the carburized and hardened carbon steel and the fatigue strength.

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

(overall structure)
FIG. 5 is a block diagram showing an example of a fuel supply system including a fuel supply pump (which may be called a high pressure fuel pump). The portion surrounded by a broken line shows the pump body 1 of the fuel supply pump, and the mechanism shown in the broken line shows that the parts and components are integrally incorporated into the pump body 1 of the fuel supply pump.

  The fuel of the fuel tank 20 is pumped up by a feed pump 21 based on a signal from an engine control unit (ECU) 21. The fuel is pressurized to an appropriate feed pressure and sent through the suction pipe 28 to the low pressure fuel inlet 10a of the fuel supply pump. The fuel that has passed through the suction joint 51 from the low pressure fuel suction port 10a reaches the suction port 31b of the electromagnetic suction valve mechanism 300 that constitutes the capacity variable mechanism through the pressure pulsation reduction mechanism 9 and the suction passage 10d.

  The fuel flowing into the electromagnetic suction valve mechanism 300 passes through the suction valve 30 and flows into the pressurizing chamber 11. The cam mechanism 93 (see FIG. 1) of the engine provides the plunger 2 with power to reciprocate. The reciprocating motion of the plunger 2 sucks the fuel from the suction valve 30 during the downward stroke of the plunger 2 and the fuel is pressurized during the upward stroke. The pressurized fuel is pressure-fed through the discharge valve mechanism 8 to the common rail 23 on which the pressure sensor 26 is mounted.

  The common rail 23 is provided with an injector 24 (so-called direct injection injector) for injecting fuel directly to a cylinder of an engine (not shown) and a pressure sensor 26. The direct injectors 24 are mounted in accordance with the number of cylinders (cylinders) of the engine, and open and close according to the control signal of the ECU 27 to inject fuel into the cylinders. The fuel supply pump (fuel supply pump) of this embodiment is applied to a so-called direct injection engine system in which the injector 24 injects fuel directly into the cylinder of the engine.

  When an abnormal high pressure occurs in the common rail 23 due to a failure of the direct injection injector 24 or the like, the differential pressure between the pressure of the fuel discharge port 12 of the fuel supply pump and the pressure of the pressurizing chamber 11 is equal to or higher than the opening pressure of the relief valve mechanism 200 Then, the relief valve 202 opens. In this case, the fuel that has become abnormally high pressure in the common rail 23 passes through the inside of the relief valve mechanism 200 and is returned to the pressurizing chamber 11 from the relief passage 200 a. This makes it possible to protect the common rail 23 (high pressure piping). The present invention can be similarly applied to a system in which the relief passage 200a is connected to the low pressure fuel chamber 10 (see FIG. 1) and the fuel which has become abnormally high pressure is returned to the low pressure passage.

  The fuel supply pump of this embodiment will be described with reference to FIGS. 1, 2 and 3. FIG. FIG. 1 is a cross-sectional view showing a cross section parallel to the central axis direction of a plunger in the fuel supply pump of the present embodiment. FIG. 2 is a horizontal sectional view of the fuel supply pump of the present embodiment as viewed from above. FIG. 3 is a cross-sectional view of the fuel supply pump of this embodiment as viewed from a direction different from FIG.

  Although the suction joint 51 is provided on the side surface of the body in FIG. 2, the present invention is not limited to this, and the invention is also applied to a fuel supply pump having the suction joint 51 provided on the upper surface of the damper cover 14. It is possible. The suction joint 51 is connected to a low pressure pipe for supplying fuel from the fuel tank 20 of the vehicle, and the fuel flowing from the low pressure fuel suction port 10 a of the suction joint 51 is a low pressure passage formed in the pump body 1 Flow through. A suction filter (not shown) press-fit into the pump body 1 is provided at the inlet of the fuel passage formed in the pump body 1, and foreign matter present between the fuel tank 20 and the low pressure fuel suction port 10a Prevents it from flowing into the fuel supply pump.

  The fuel flows from the suction joint 51 upward in the axial direction of the plunger and flows into the low pressure fuel chamber 10 formed by the damper upper portion 10b and the damper lower portion 10c shown in FIG. The low pressure fuel chamber 10 is formed by being covered by a damper cover 14 attached to the pump body 1. The fuel whose pressure pulsation has been reduced by the pressure pulsation reducing mechanism 9 in the low pressure fuel chamber 10 reaches the suction port 31b of the electromagnetic suction valve mechanism 300 via the low pressure fuel passage 10d. The electromagnetic suction valve mechanism 300 is attached to a lateral hole formed in the pump body 1 and supplies fuel of a desired flow rate to the pressure chamber 11 through the pressure chamber inlet flow path 1 a formed in the pump body 1. An O-ring 61 is fitted into the pump body 1 for sealing between the cylinder head 90 and the pump body 1 to prevent engine oil from leaking to the outside.

  As shown in FIG. 1, the pump body 1 is provided with a cylinder 6 for guiding the reciprocating motion of the plunger 2. The cylinder 6 is fixed to the pump body 1 by press fitting and caulking on the outer peripheral side thereof. The cylindrical press-fit portion of the cylinder 6 seals the fuel pressurized from the gap with the pump body 1 so as not to leak to the low pressure side. The cylinder 6 has a double seal structure in addition to the seal of the cylindrical press-fit portion of the pump body 1 and the cylinder 6 by bringing the upper end face into axial contact with the plane of the pump body 1.

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

  Further, a plunger seal 13 held at the lower end portion of the inner periphery of the seal holder 7 is installed in a state where the plunger seal 13 slidably contacts the outer periphery of the plunger 2 at the lower portion in the drawing of the cylinder 6. Thus, when the plunger 2 slides, the fuel in the sub chamber 7a is sealed to prevent the fuel from flowing into the internal combustion engine. At the same time, the plunger seal 13 prevents lubricating oil (including engine oil) for lubricating the sliding portion in the internal combustion engine from flowing into the pump body 1.

  As shown in FIG. 2, the pump body 1 has a lateral hole for mounting the electromagnetic suction valve mechanism 300, a lateral hole for mounting the discharge valve mechanism 8 at the same position in the plunger axial direction, a lateral hole for mounting the relief valve mechanism 200, A lateral hole for mounting the discharge joint 12c is formed. The fuel pressurized in the pressure chamber 11 through the electromagnetic suction valve mechanism 300 flows through the discharge passage 12b through the discharge valve mechanism 8 and is discharged from the fuel discharge port 12 of the discharge joint 12c.

  The discharge valve mechanism 8 (FIGS. 2 and 3) provided on the outlet side of the pressure chamber 11 directs the discharge valve seat 8a, the discharge valve 8b contacting with and separating from the discharge valve seat 8a, and the discharge valve 8b toward the discharge valve seat 8a. It comprises a discharge valve spring 8c, a discharge valve plug 8d, and a discharge valve stopper 8e for determining the stroke (moving distance) of the discharge valve 8b. The discharge valve plug 8d and the pump body 1 are joined by a weld 401. This joint shuts off the inside space from which the fuel flows and the outside. Further, the discharge valve seat 8 a is joined to the pump body 1 by the press-fit portion 402.

  In the state where there is no differential pressure between the fuel pressure of the pressure chamber 11 and the fuel pressure of the discharge valve chamber 12a, the discharge valve 8b is crimped to the discharge valve seat 8a by the biasing force of the discharge valve spring 8c and is closed. . Only when the fuel pressure in the pressure chamber 11 becomes higher than the fuel pressure in the discharge valve chamber 12a, the discharge valve 8b opens against the discharge valve spring 8c. The high pressure fuel in the pressure chamber 11 is discharged to the common rail 23 through the discharge valve chamber 12 a, the discharge passage 12 b, and the fuel discharge port 12. When the discharge valve 8 b is opened, the discharge valve 8 b contacts the discharge valve stopper 8 e and the stroke is limited. Therefore, the stroke of the discharge valve 8b is appropriately determined by the discharge valve stopper 8e. This makes it possible to prevent the fuel discharged at high pressure into the discharge valve chamber 12a from flowing back again into the pressurizing chamber 11 due to the stroke being too long and the closing of the discharge valve 8b, and the efficiency of the fuel supply pump is lowered. Can be suppressed. Further, when the discharge valve 8b repeats the opening and closing operations, the discharge valve 8b is guided by the outer peripheral surface of the discharge valve stopper 8e such that the discharge valve 8b moves only in the stroke direction.

As described above, the pressure chamber 11 is configured by the pump body 1, the electromagnetic suction valve mechanism 300, the plunger 2, the cylinder 6, and the discharge valve mechanism 8. Further, as shown in FIGS. 2 and 3, the fuel supply pump of this embodiment is in close contact with the flat surface of the cylinder head 90 of the internal combustion engine using the mounting flange 1b provided on the pump body 1 and fixed by a plurality of bolts not shown. Be done.
The relief valve mechanism 200 includes a seat member 201, a relief valve 202, a relief valve holder 203, a relief spring 204, and a holder member 205. The relief valve mechanism 200 is a valve configured to operate when a problem occurs in the common rail 23 or the member beyond it and becomes abnormally high, and the pressure in the common rail 23 or the member beyond that increases. In this case, it has the role of opening the valve and returning the fuel to the pressurizing chamber 11 or the low pressure passage (such as the low pressure fuel chamber 10 or the suction passage 10d). Therefore, it is necessary to maintain the valve closing state below a predetermined pressure, and has a very strong spring 204 to counter the high pressure.

  The electromagnetic suction valve mechanism 300 will be described with reference to FIG. FIG. 4 is an enlarged cross sectional view showing a cross section parallel to the drive direction of the suction valve in the electromagnetic suction valve mechanism of the present embodiment, and is a cross sectional view showing a state in which the suction valve is opened.

  In the non-energized state, the strong rod biasing spring 40 causes the suction valve 30 to operate in the valve opening direction and is normally open. When a control signal from the ECU 27 is applied to the electromagnetic suction valve mechanism 300, a current flows in the electromagnetic coil 43 via the terminal 46. When current flows through the electromagnetic coil 43, the movable core 36 is attracted in the valve closing direction by the magnetic attraction force of the magnetic core 39 on the magnetic attraction surface S. The rod biasing spring 40 is disposed in a recess formed in the magnetic core 39 and biases the flange portion 35a. The flange portion 35 a engages with the recess of the movable core 36 on the side opposite to the rod biasing spring 40.

  The magnetic core 39 is configured to be in contact with the lid member 44 covering the electromagnetic coil chamber in which the electromagnetic coil 43 is disposed. When the movable core 36 is attracted and moved by the magnetic core 39, the flange 35a of the rod 35 is engaged, and the rod 35 is moved together with the movable core 36 in the valve closing direction. Between the movable core 36 and the suction valve 30, a valve closing spring 41 for urging the movable core 36 in the valve closing direction and a rod guide member 37 for guiding the rod 35 in the opening and closing direction are disposed. Ru. The rod guide member 37 constitutes a spring seat 37 b of the valve closing biasing spring 41. Further, a fuel passage 37a is provided in the rod guide member 37 to allow the fuel to flow into and out of the space in which the movable core 36 is disposed.

  The movable core 36, the valve closing spring 41, the rod 35 and the like are contained in an electromagnetic suction valve mechanism housing 38 fixed to the pump body 1. Further, the magnetic core 39, the rod biasing spring 40, the electromagnetic coil 43, the rod guide member 37 and the like are held by the electromagnetic suction valve mechanism housing 38. The rod guide member 37 is attached to the electromagnetic suction valve mechanism housing 38 on the opposite side to the magnetic core 39 and the electromagnetic coil 43, and includes the suction valve 30, the suction valve biasing spring 33 and the stopper 32. Do.

  On the opposite side of the magnetic core 39 of the rod 35, an intake valve 30, an intake valve biasing spring 33 and a stopper 32 are provided. The suction valve 30 is formed with a guide portion 30 b which protrudes toward the pressurizing chamber 11 and is guided by the suction valve biasing spring 33. The suction valve 30 is opened by moving in the valve opening direction (direction away from the valve seat 31a) by the gap of the valve body stroke 30e along with the movement of the rod 35, and the supply passage 10d enters the pressure chamber 11. Fuel is supplied. The guide portion 30 b stops its movement by colliding with a stopper 32 which is press-fitted and fixed inside the housing (rod guide member 37) of the electromagnetic suction valve mechanism 300. The rod 35 and the suction valve 30 are separate and independent structures. The suction valve 30 closes the flow path to the pressurizing chamber 11 by coming into contact with the valve seat 31a of the valve seat member 31 disposed on the suction side, and by separating from the valve seat 31a, the flow path to the pressurizing chamber 11 Configured to open.

  When the plunger 2 moves in the direction (downward direction) of the cam 93 by the rotation of the cam 93 in FIG. 1 and in the suction stroke state, the volume of the pressure chamber 11 increases and the fuel pressure in the pressure chamber 11 increases. descend. When the electromagnetic coil 43 is deenergized in this suction stroke, the sum of the biasing force of the rod biasing spring 40 and the pressure of the suction passage 10d becomes larger than the fuel pressure in the pressurizing chamber 11, and the rod 35 The suction valve 30 is biased in the valve opening direction to open.

  When the plunger 2 reaches the bottom dead center and the suction stroke is finished, the plunger 2 starts to move upward. Here, the electromagnetic coil 43 remains in the non-energized state, and the magnetic bias does not act. The volume of the pressure chamber 11 decreases with the compression movement of the plunger 2. In this state, the fuel once sucked into the pressure chamber 11 passes through the opening of the suction valve 30 in the open state again through the suction passage. Since the pressure is returned to 10d, the pressure in the pressure chamber 11 does not rise. This process is called a return process.

  Thereafter, by turning on the energization of the electromagnetic coil 43 at a desired timing, the magnetic attraction force is generated as described above, whereby the rod 35 moves together with the movable core 36 in the valve closing direction, and the tip 35b of the rod 35 Leaves the suction valve 30. In this state, the suction valve 30 is a check valve that opens and closes according to the differential pressure, so the valve is closed by the biasing force of the suction valve biasing spring 33. After the suction valve 30 is closed, since the plunger 2 is raised, the volume of the pressure chamber 11 is reduced and the fuel is pressurized. This is called a compression stroke. When the fuel in the pressure chamber 11 is pressurized and exceeds the sum of the fuel pressure in the discharge valve chamber 12a and the biasing force of the discharge valve spring 8c, the discharge valve 8b is opened to discharge the fuel.

  By controlling the energization timing of the electromagnetic coil 43 of the electromagnetic suction valve mechanism 300, the amount of high pressure fuel to be discharged can be controlled. If the timing for energizing the electromagnetic coil 43 is advanced, the proportion of the return stroke in the compression stroke is small, and the proportion of the discharge stroke is large. That is, the amount of fuel returned to the suction passage 10d decreases, and the amount of fuel discharged to the common rail 23 at high pressure increases. On the other hand, if the timing of energization is delayed, the proportion of the return stroke during the compression stroke is large, and the proportion of the discharge stroke is small. That is, the amount of fuel returned to the suction passage 10d increases, and the amount of fuel discharged to the common rail 23 at high pressure decreases. The energization timing of the electromagnetic coil 43 is controlled by a command from the ECU 27.

As described above, by controlling the energization timing of the electromagnetic coil 43, the amount of high-pressure discharged fuel can be controlled to the amount required by the internal combustion engine.
The low pressure fuel chamber 10 is provided with a pressure pulsation reducing mechanism 9 for reducing the pressure pulsation generated in the fuel supply pump from spreading to the fuel pipe 28. Moreover, the damper upper part 10b and the damper lower part 10c are provided at intervals above and below the pressure pulsation reducing mechanism 9, respectively. In the case where the fuel that has once flowed into the pressurizing chamber 11 is returned to the suction passage 10d through the suction valve 30 that is in the open state again for volume control, pressure pulsation is generated in the low pressure fuel chamber 10 by the fuel returned to the suction passage 10d. Occurs. However, the pressure pulsation reducing mechanism 9 provided in the low pressure fuel chamber 10 is formed by a metal diaphragm damper in which two corrugated disc-like metal plates are laminated at their outer periphery and an inert gas such as argon is injected therein. The pressure pulsation is absorbed and reduced by the expansion and contraction of the metal damper. Reference numeral 9a denotes a mounting bracket for fixing the metal damper to the inner peripheral portion of the pump body 1, and is installed on the fuel passage, so the supporting portion with the damper is not a full circumference but a part of the mounting bracket 9a. The fluid is allowed to freely move back and forth.

  The plunger 2 has a large diameter portion 2a and a small diameter portion 2b, and the volume of the sub chamber 7a is increased or decreased by the reciprocating motion of the plunger 2. The sub chamber 7a communicates with the low pressure fuel chamber 10 through a fuel passage 10e (see FIG. 3). When the plunger 2 is lowered, a flow of fuel is generated from the sub chamber 7a to the low pressure fuel chamber 10, and when it is raised, a flow of fuel from the low pressure fuel chamber 10 to the sub chamber 7a.

  As a result, the fuel flow rate into and out of the pump in the suction stroke or return stroke of the pump can be reduced, and the pressure pulsation generated inside the fuel supply pump can be reduced.

  Further, the operation of the relief valve mechanism will be described in detail. As shown in FIG. 2, the relief valve mechanism 200 includes a seat member 201, a relief valve 202, a relief valve holder 203, a relief spring 204, and a relief spring stopper 205. The relief valve 202, the relief valve holder 203, and the relief spring 204 are sequentially inserted into the seat member 201, and the relief spring stopper 205 is fixed by press fitting or the like. The pressing force of the relief spring 204 is defined by the position of the relief spring stopper 205. The valve opening pressure of the relief valve 202 is set to a specified value by the pressing force of the relief spring 204. The relief valve mechanism 200 thus unitized is fixed to the pump body 1 by press fitting or the like as shown in FIG. Although FIG. 1 shows the unitized relief valve mechanism 200, the present invention is not limited to this. Since the fuel supply pump needs to pressurize the fuel to a very high pressure of several MPa to several tens MPa, the set valve opening pressure of the relief valve 202 must be higher than that.

Hereinafter, examples of the present invention will be described in detail. In the present embodiment, the plunger 2 shown in FIGS. The fuel supply pump of this embodiment is attached to the pump body 1 in which the pressurizing chamber 11 is formed, the plunger 2 for pressurizing the fuel in the pressurizing chamber 11 by reciprocating motion, and the biasing force of the spring 4 by being attached to the plunger 2 And a retainer 15 for urging the plunger 2 to the opposite side of the pressure chamber 11. In the present embodiment, the retainer 15 is formed of carburized and hardened carbon steel.
FIG. 6 shows the hardness distribution of the carburized and quenched retainer. Assuming that the thickness of the material is T and the base material hardness range is t, the base material hardness ratio is t / T × 100 (%). Here, in recent years, a high pressure fuel pump is required to have a higher pressure, such as a discharge pressure of 30 MPa or more. Therefore, since the biasing force of the spring 4 also becomes strong accordingly, a large stress is generated in the retainer 15 that holds the plunger 2, which may cause breakage of the retainer 15. The inventors of the present invention are required to use a metal having high hardness on the metal surface and high toughness (stickiness) inside the metal in order to form the highly reliable retainer 15 against this large stress. I found that there is.

  For this purpose, the present inventors have found that a metal standardized as SCM 415 according to the Japanese Industrial Standard (JIS) as a carbon steel is optimal. SCM 415 contains 0.13 to 0.18% carbon and has an elongation of 16% or more. Other carbon steels may be configured with SCM 415. Further, in the present embodiment, in order to secure strength, the retainer 15 is configured to have a plate thickness of 1.8 mm or more. In the case where inexpensive carbon steel is used for the retainer 15 in order to balance manufacturing cost and strength, heat treatment such as carburizing and quenching is required to ensure sufficient strength. The fatigue strength is sensitive to the proportion of the base material hardness range after carburizing and quenching, and sufficient strength can not be satisfied if the heat treatment conditions are mistaken.

  FIG. 7 is a graph showing the relationship between the ratio of the base material hardness range of the carburized and quenched carbon steel and the fatigue strength. The carburized and quenched carbon steel shows that the fatigue strength is maximum at a certain rate in the base material hardness range. In the present embodiment, the retainer 15 is configured such that the ratio of the portion of the base material hardness in the thickness direction is 28% or more of the thickness. That is, t / T × 100 (%) ≧ 28. As a result, the present inventors are configured such that the fatigue strength of the retainer 15 is 400 MPa, and it is possible to provide a highly reliable fuel supply pump. On the other hand, as shown in FIG. 7, the present inventors found that when t / T × 100 (%) exceeds 60%, the fatigue strength tends to decrease. That is, the relationship between the base material hardness and the fatigue strength of the material of the retainer 14 has a property of having a maximum value with respect to the fatigue strength. Therefore, in the present embodiment, the retainer 15 has a base material hardness region in the plate thickness direction. The ratio is configured to be 60% or less of the plate thickness. That is, the base material hardness ratio (t / T × 100 (%)) to the thickness T of the retainer 15 is up to the maximum value (60% in this embodiment).

  As described above, the present embodiment is characterized in that the base material hardness ratio of FIG. 6 is used in the range equal to or less than the maximum value of the fatigue strength. As described above, when the fatigue strength exceeds the maximum value, the quenching depth may be reduced and the required hardness may not be obtained. However, according to this embodiment, this can be avoided. There is also a method of increasing the thickness of the material to obtain the necessary hardness, but this increases the cost. On the other hand, in the present embodiment, since it is not necessary to increase the plate thickness more than necessary, the cost can be reduced.

Reference Signs List 1 pump housing 2 plunger 4 spring 6 cylinder 7 seal holder 8 discharge valve mechanism 9 pressure pulsation reducing mechanism 10a low pressure fuel suction port 10d suction passage 11 addition 11 Pressure chamber, 12: fuel discharge port, 13: plunger seal, 14: housing cover, 15: retainer, 28: suction pipe, 30: suction valve, 51: suction joint, 300: electromagnetic suction valve.

Claims (6)

A fuel supply pump comprising: a plunger for pressurizing fuel in a pressure chamber by reciprocating movement; and a retainer for being attached to the plunger to bias the plunger to the opposite side of the pressure chamber by an urging force of a spring. ,
A fuel supply pump characterized in that the retainer is formed of carburized and hardened carbon steel. In the fuel supply pump according to claim 1,
The said carbon steel was comprised with the metal standardized as SCM415 by Japanese Industrial Standard (JIS), The fuel supply pump characterized by the above-mentioned. In the fuel supply pump according to claim 1,
The fuel supply pump, wherein the retainer has a plate thickness of 1.8 mm or more. In the fuel supply pump according to claim 1,
The fuel supply pump, wherein the retainer has a base material hardness ratio of 28% or more of the plate thickness in the plate thickness direction. In the fuel supply pump according to claim 1,
The fuel supply pump, wherein the retainer has a base material hardness ratio of 60% or less of the plate thickness in the plate thickness direction. In the fuel supply pump according to claim 1,
The fuel supply pump comprised so that the fatigue strength of the said retainer might be 400 Mpa.

Images