JP2017141725A - High pressure fuel supply pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of a cutout shape at a discharge joint welding part of a high pressure fuel supply pump, to obtain desired fatigue strength at the discharge joint welding part.SOLUTION: A high pressure fuel supply pump comprising a first member and a second member opposite to one surface of the first member, includes a welding part configured to fix the first member and the second member, and a cavity formed by the welding part, the first member and the second member, on an opposite side to a welding portion with a welding laser of the welding part. At least one of a cavity constitution surface of the first member and a cavity constitution surface of the second member constituting the cavity is formed outside with respect to a weld penetration width of the welding part.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a high-pressure fuel supply pump that supplies high-pressure fuel to a fuel injection valve that directly injects fuel into a cylinder of an internal combustion engine, and in particular, a discharge joint for supplying high-pressure fuel to a common rail includes the high-pressure fuel supply pump. The present invention relates to a high-pressure fuel supply pump that is joined to the main body by welding.

  Japanese Patent Application Laid-Open No. 2011-80391 describes a high-pressure fuel supply pump in which a discharge joint for supplying high-pressure fuel to a common rail is coupled to the main body of the high-pressure fuel supply pump by laser welding from the outside.

  By connecting the discharge joint to the high-pressure fuel supply pump by laser welding from the outside, even if high-pressure fuel is supplied inside the discharge joint, the fuel can be supplied to the common rail without leaking outside.

  Further, in Japanese Patent Application Laid-Open No. 2011-80391, on the opposite side of the discharge joint welded portion to the portion where the welding laser hits, a gap portion for preventing stress concentration at the welded portion and distributing the stress evenly throughout the welded portion. It is described that it is provided.

JP 2011-80391 A

  However, in the discharge joint welded portion described in the prior art document, the pump body side gap configuration that constitutes the gap portion in the gap provided on the opposite side of the portion where the welding laser hits the discharge joint welded portion The surface and the discharge joint-side gap forming surface are formed substantially on the same line with respect to the weld penetration width of the discharge joint welded portion or at a position where the distance in the lateral direction is very close. In this case, when the discharge joint is welded, an acute angle shape (hereinafter referred to as a notch shape) tends to occur in a part of the welded portion. When a notch shape is generated in the gap portion, stress concentration occurs in that portion, so that there is a problem that the fatigue strength of the discharge joint weld portion does not become as expected.

  An object of the present invention is to suppress the occurrence of a notch shape at a discharge joint weld of a high-pressure fuel supply pump, and to obtain a desired fatigue strength at the discharge joint weld.

  In the present invention, in order to achieve the above object, in a high-pressure fuel supply pump comprising a first member and a second member facing one surface of the first member, the first member and the second member are A welded portion to be fixed; and a gap formed by the welded portion, the first member, and the second member on a side opposite to a welded portion of the welded portion by a welding laser, and constituting the gap. At least one of the void-constituting surface of one member and the void-constituting surface of the second member was formed on the outer side with respect to the penetration width of the welded portion.

  According to the present invention configured as described above, it is possible to suppress the occurrence of a notch shape in the discharge joint weld and to obtain a desired fatigue strength at the discharge joint weld.

1 is an example of a fuel supply system diagram including a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented; 1 is a longitudinal sectional view of a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented. It is another longitudinal cross-sectional view of the high-pressure fuel supply pump by the 1st Example by which this invention was implemented. 1 is an enlarged longitudinal sectional view of an electromagnetic intake valve of a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented, showing a state where the electromagnetic intake valve is in an open state. 1 is an enlarged longitudinal sectional view of an electromagnetic suction valve of a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented, showing a state where the electromagnetic suction valve is in a closed state. FIG. 3 is an enlarged longitudinal sectional view of a discharge joint welded portion of the high-pressure fuel supply pump according to the first embodiment in which the present invention is implemented, in a case where there is no step on the air gap side between the pump body and discharge joint that are welded by laser. is there. FIG. 3 is an enlarged longitudinal sectional view of a discharge joint welded portion of the high-pressure fuel supply pump according to the first embodiment in which the present invention is implemented, in a case where there is a step on the air gap side between the pump body and discharge joint that are welded by laser. is there. It is an enlarged vertical sectional view of the discharge joint welded portion of the high-pressure fuel supply pump, and is a view for explaining a case where an acute notch shape is formed between the discharge joint welded portion and the air gap constituting surface.

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

  The configuration of a high-pressure fuel supply pump that is an embodiment of the present invention will be described with reference to FIGS.

  In FIG. 1, a portion surrounded by a broken line indicates a pump body 1 of a high-pressure fuel supply pump, and mechanisms and parts shown in the broken line are integrated into the pump body 1 of the high-pressure fuel supply pump. Indicates that

  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 sucked into the low pressure fuel of the high pressure fuel supply pump through the suction pipe 28. It is sent to the mouth 10a.

  In FIG. 2, a damper cover 14 is fixed to the head of the pump body 1. The damper cover 14 is provided with a suction joint 101 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 102 fixed inside the suction joint 101, and further passes through the low-pressure fuel flow path 10b, the pressure pulsation reduction mechanism 9, and the low-pressure fuel flow path 10c, and the electromagnetic suction valve. 30 intake passages 30a.

  The suction filter 102 in the suction joint 101 serves to prevent foreign matter existing between the fuel tank 20 and the low-pressure fuel inlet 10a from being absorbed into the high-pressure fuel supply pump by the flow of fuel.

  The pump body 1 is formed with a depression 1 </ b> A so as to protrude upward as a pressurizing chamber 11 at the center, and an electromagnetic suction valve 30 is provided in the suction passage 30 a at the inlet of the pressurizing chamber 11. . As shown in FIG. 4, the electromagnetic suction valve 30 is provided with a movable portion 31 composed of an anchor 31b and a rod 31a. The anchor spring 34 urges the anchor 31b in the valve opening direction (left direction in FIG. 4) via the rod 31a, and the rod 31a urges the suction valve 39 in the valve opening direction at the tip. On the other hand, the suction valve 39 is urged by the suction valve spring 38 in the valve closing direction (right direction in FIG. 4). Since the urging force of the anchor spring 34 is larger than the urging force of the suction valve spring 38, the anchor 31b and the rod 31a move to the left in the figure as shown in FIG. 4 when the electromagnetic coil 52 is in a non-energized state. Then, the suction valve 39 comes into contact with the suction valve holder 35 and the movement is restricted, and the valve is opened. That is, the anchor 31b and the rod 31a are urged in the valve opening direction due to the difference between the urging force of the anchor spring 34 and the urging force of the suction valve spring 38 in the non-energized state. The suction valve holder 35 functions as a stopper for the suction valve 39. Thus, the electromagnetic suction valve 30 communicates the suction passage 30a with the pressurizing chamber 11 when the electromagnetic coil 52 is not energized.

The outer periphery of the cylinder 6 is a cylindrical fitting portion 7a of the cylinder holder 7
Is held by. The cylinder 6 is fixed to the pump body 1 by screwing a screw 7 g threaded on the outer periphery of the cylinder holder 7 into a screw 1 b threaded on the pump body 1. The plunger seal 13 is held at the lower end of the cylinder holder 7 by the seal holder 16 and the cylinder holder 7 that are press-fitted and fixed to the inner peripheral cylindrical surface 7 c of the cylinder holder 7. At this time, the plunger seal 13 is held by the inner peripheral cylindrical surface 7c of the cylinder holder 7 so that its axis is coaxial with the axis of the cylindrical fitting portion 7a. The plunger 2 and the plunger seal 13 are installed in a slidable contact state at the lower end of the cylinder 6 in the figure.

  This prevents the fuel in the annular low pressure seal chamber 10f from flowing into the tappet 3 side, that is, the inside of the engine. At the same time, lubricating oil (including engine oil) that lubricates the sliding portion in the engine room is prevented from flowing into the pump body 1. Further, the cylinder holder 7 is provided with an outer peripheral cylindrical surface 7b, in which a groove 7d for fitting the O-ring 61 is provided. The O-ring 61 shuts off the engine cam side and the outside by the inner wall of the engine-side fitting hole 70 and the groove 7d of the cylinder holder 7 and prevents engine oil from leaking outside.

  The cylinder 6 has a crimping portion 6 a that intersects the reciprocating direction of the plunger 2, and the crimping portion 6 a is crimped to the crimping surface 1 a of the pump body 1. The crimping is performed by thrust generated by tightening the screw 7g. The pressurizing chamber 11 is formed by this pressure bonding, so that even if the fuel in the pressurizing chamber 11 is pressurized to a high pressure, the screw 7g prevents the fuel from leaking out of the pressure chamber 11 through the pressure bonding portion. The tightening torque must be controlled.

  Further, in order to keep the sliding length of the plunger 2 and the cylinder 6 properly, the cylinder 6 is deeply inserted into the pressurizing chamber 11. A clearance 1 </ b> B is provided between the outer periphery of the cylinder 6 and the inner periphery of the pump body 1 on the pressure chamber 11 side of the crimping portion 6 a of the cylinder 6. Since the outer periphery of the cylinder 6 is held by the cylindrical fitting portion 7a of the cylinder holder 7, the clearance 1B is provided so that the outer periphery of the cylinder 6 and the inner periphery of the pump body 1 do not come into contact with each other. it can. As described above, the cylinder 6 holds the plunger 2 that moves forward and backward in the pressurizing chamber 11 so as to be slidable along the forward and backward movement direction.

  At the lower end of the plunger 2, a retainer 15 that converts the rotational motion of the cam 5 into vertical motion and transmits it to the plunger 2 is fixed to the plunger 2 by fitting, and the plunger 2 is fixed by a spring 4 via the retainer 15. It is pressed against the inner surface of the bottom of the tappet 3. Thereby, the plunger 2 can be moved up and down with the rotational movement of the cam 5.

A discharge valve unit 8 is provided at the outlet of the pressurizing chamber 11. The discharge valve unit 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 to each other by a welding portion 8e at a contact portion to form an integral unit. 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.
Is provided.

  When the discharge valve 8b is opened, it comes into contact with the discharge valve holder 8d, and the stroke is limited. Therefore, the stroke of the discharge valve 8b is appropriately determined by the discharge valve holder 8d. As a result, it is possible to prevent the fuel that has been discharged at a high pressure into the discharge joint 12 due to a delay in closing the discharge valve 8b from flowing back into the pressurizing chamber 11 again due to a delay in closing the discharge valve 8b. Reduction can be suppressed. In addition, when the discharge valve 8b repeats opening and closing movements, the discharge valve 8b is guided on the inner peripheral surface of the discharge valve holder 8d so as to move only in the stroke direction. As described above, the discharge valve unit 8 serves as a check valve that restricts the flow of fuel in one direction and the reverse flow. As described above, the pressurizing chamber 11 according to the present embodiment includes the pump body 1, the electromagnetic suction valve 30, the plunger 2, the cylinder 6, and the discharge valve unit 8. The discharge valve chamber in which the discharge valve unit 8 is disposed is constituted by a recess formed on the discharge side of the pump body 1, and the discharge valve seat 8a of the discharge valve unit 8 is press-fitted into the inner peripheral surface 11A of the recess. Thus, the discharge valve chamber and the pressurizing chamber 11 are partitioned.

  Thus, the fuel guided to the low-pressure fuel inlet 10a is sent to the pressurizing chamber 11 of the pump body 1 as the pump body. Here, in a state where there is no fuel differential pressure inside the pressurizing chamber 11 and the discharge joint 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 in a closed state. The discharge valve 8b opens against the discharge valve spring 8c only when the fuel is pressurized to a high pressure by the reciprocating motion of the plunger 2 in the pressurizing chamber 11 and the fuel pressure becomes higher than the fuel pressure inside the discharge joint 12. The high pressure fuel in the pressurizing chamber 11 is discharged to the common rail 23 through the discharge joint 12.

  An injector 24 and a pressure sensor 26 are attached to the common rail 23. The injectors 24 are mounted according to the number of cylinders of the internal combustion engine, and open and close according to the control signal of the ECU 27 to inject fuel into the cylinders.

The high pressure fuel supply pump is fixed to the engine by a mounting flange 41, a bolt 42, and a bush 43.
Is done. The mounting flange 41 is welded and joined to the pump body 1 by a welded portion 41a to form an annular fixed portion. In this embodiment, laser welding is used.

  FIG. 4 is an enlarged view of the electromagnetic intake valve 30, and shows a non-energized state where the electromagnetic coil 52 is not energized. FIG. 5 is an enlarged view of the electromagnetic suction valve 30, and shows a state where the electromagnetic coil 52 is energized.

  The movable part 31 consists of two parts, a rod 31a and an anchor 31b. The rod 31a and the anchor 31b are separate types, and a minute clearance is provided between the rod 31a and the anchor 31b. Since the rod 31a is also slidably held by a sliding portion 32d of the valve seat 32, which will be described later, the movement of the anchor 31b is limited only in the direction of the valve opening / closing movement by the rod 31a. Held possible.

  As shown in FIG. 4, the suction valve spring 38 is fitted into the suction valve 39 and the suction valve holder 35, and a biasing force is generated by the suction valve spring 38 in a direction in which the suction valve 39 and the suction valve holder 35 are separated. Yes.

  As shown in FIG. 4, the anchor spring 34 is fitted into the anchor inner periphery 31 c and the core inner periphery 33 b, and a biasing force is generated by the anchor spring 34 in a direction in which the anchor 31 b and the core 33 are pulled apart. The biasing force by the anchor spring 34 is set to be larger than the biasing force by the suction valve spring 38. Therefore, when the electromagnetic coil 52 is not energized, the movable portion 31 is urged in the valve opening direction on the left side of the drawing as shown in FIG. 4 due to the difference between the urging force by the anchor spring 34 and the urging force by the suction valve spring 38. The valve 39 is open.

  The valve seat 32 includes a suction valve seat portion 32a, a suction passage portion 32b, a press-fit portion 32c, and a sliding portion 32d. The press-fit portion 32 c is press-fitted and fixed to the core 33. The suction valve seat portion 32 a is press-fitted and fixed to the suction valve holder 35, and the suction valve holder 35 is press-fitted and fixed to the pump body 1. Thereby, the pressurizing chamber 11 and the suction passage 30a are completely shut off. A rod 31a is slidably held by the sliding portion 32d.

  The core 33 includes a first core portion 33a, a magnetic orifice portion 33b, a core inner periphery 33c, and a second core portion 33d. When the electromagnetic coil 52 is energized, a magnetic flux is generated by a magnetic field generated around the electromagnetic coil 52 as shown in FIG. 4, and a magnetic attractive force is generated between the anchor 31 b and the core 33. In this embodiment, the members constituting the magnetic circuit are an anchor 31b, a core 33, and a yoke 51 as shown in FIG. 4, and all of these materials are magnetic materials. In order to increase the magnetic attractive force, the magnetic flux passing through the magnetic attractive surface S of the anchor 31b and the core 33 may be increased. For this purpose, a magnetic orifice part 33b is provided between the first core part 33a and the second core part 33d. In the magnetic orifice portion 33b, the thickness is made as thin as possible in strength, while the other portions of the core 33 have a sufficient thickness. The magnetic orifice portion 33b is provided in the vicinity of the portion where the core 33 and the anchor 31b are in contact. As a result, the magnetic flux passing through the magnetic restricting portion 33b of the core 33 can be reduced, so that most of the magnetic flux passes through the anchor 31b, thereby allowing a reduction in the magnetic attractive force generated between the core 33 and the anchor 31b. Inside.

  If the cross-sectional area of the magnetic orifice portion 33b is too large, the magnetic flux directly passes between the first core portion 33a and the second core portion 33d, and the magnetic flux passing through the anchor 31b is reduced. It will decline. If the magnetic attractive force is small, the response of the movable part 31 is poor and the intake valve cannot be closed, or the time until the valve is closed becomes long, and the internal combustion engine is operated at high speed (when the cam rotates at high speed). In addition, there arises a problem that the amount of fuel discharged at high pressure cannot be controlled.

  With the structure of this embodiment, it is not necessary to use a nonmagnetic material for the magnetic orifice portion 33b, and the core 33 can be manufactured as an integral part. Therefore, it is not necessary to couple the core 33 and the non-magnetic material using press-fitting, welding, or the like when the core 33 is assembled, and the processing and assembly of the parts can be simplified. The core 33 is welded and fixed to the pump body 1 by a welded portion 37, and shuts off the suction passage 30a and the outside of the high-pressure fuel supply pump.

  When the electromagnetic coil 52 is not energized and is not energized, and when there is no fluid differential pressure between the low pressure fuel passage 10c (suction passage 30a) and the pressurizing chamber 11, the movable portion 31 is connected to the anchor spring 34. Due to the difference in the urging force of the suction valve spring 38, it moves to the left in the figure as shown in FIG. At this time, since the suction valve 39 is in contact with the suction valve holder 35, the position of the suction valve 39 in the valve opening direction is regulated. In this state, the intake valve 39 is opened. A gap existing between the suction valve 39 and the valve seat 32 is a movable range of the suction valve 39, and this is a stroke.

  If the stroke is too large, a longer time is required after the electromagnetic coil 52 is energized until the suction valve 39 starts the valve closing motion and contacts the valve seat 32 to be completely closed. Further, since the distance between the anchor 31b and the core 33 is increased, the magnetic attractive force generated is reduced.

  For this reason, the responsiveness is insufficient during high-speed operation of the internal combustion engine (during high-speed cam rotation), the intake valve 39 cannot be closed at the target timing, and the amount of fuel discharged at high pressure cannot be controlled. Problems arise. If the stroke is too small, the orifice effect at this portion becomes large, and pressure loss occurs. For example, when the fuel temperature is a high temperature such as 60 ° C. and the internal combustion engine is operating at high speed (during high-speed rotation of the cam), the fuel flows into the pressurizing chamber 11 from the low-pressure fuel flow path 10c during the intake stroke. The fuel is vaporized in the portion, and the fuel that can be pressurized to a high pressure decreases. As a result, there has been a problem that the volume efficiency of the high-pressure fuel supply pump is reduced.

  Further, during the return process described later, during high-speed operation of the internal combustion engine (during high-speed rotation of the cam), fluid force generated in the intake valve 39 (closed generated by fuel flowing backward from the pressurizing chamber 11 to the low-pressure fuel flow path 10c) (Force in the valve direction) increases. Then, the suction valve 39 is closed at an unexpected timing during the returning process, and there arises a problem that the amount of fuel discharged at high pressure cannot be controlled. For these reasons, the management of the stroke of the suction valve 39 is very important.

  Since the stroke is determined only by the component dimensions of the suction valve holder 35 and the suction valve 39 by adopting the structure as in the present embodiment, the variation in the stroke is minimized by appropriately setting the tolerance of these component dimensions. It becomes possible to suppress to.

  The clearance between the anchor 31b and the core 33 must be set to be larger than the stroke between the suction valve 39 and the valve seat 32. If the clearance is smaller than the stroke, the anchor 31b collides with the core 33 before the suction valve 39 contacts the valve seat 32 after the suction valve 39 starts to close after the electromagnetic coil 52 is energized. There arises a problem that the valve 39 and the valve seat 32 do not contact each other, that is, the suction valve 39 cannot be completely closed. However, if the clearance is too large, a sufficient magnetic attractive force cannot be obtained even if the electromagnetic coil 52 is energized. Therefore, the movable part 31 cannot be closed, or the responsiveness is deteriorated, and the amount of fuel discharged at high pressure cannot be controlled during high speed operation of the internal combustion engine (during high speed rotation of the cam). Will occur.

  In the case of the structure of this embodiment, the clearance is determined only by the dimensions of the parts such as the suction valve holder 35, the valve seat 32, the rod 31a, the core 33, and the suction valve 39. By setting to, it becomes possible to minimize the variation in clearance.

  The electromagnetic coil 52 is not energized when the plunger 2 is in the suction process state (while moving from the top dead center position to the bottom dead center position) in which the plunger 2 is displaced downward in FIG. At this time, since the suction valve 39 is opened, the volume of the pressurizing chamber 11 increases. In this process, the fuel flows from the suction passage 30a through the suction passage portion 32b of the valve seat 32 and the suction port 36 into the pressurizing chamber 11. Since the amount of displacement of the suction valve 39 is regulated by the suction valve holder 35, the valve is not opened any further.

In this state, the plunger 2 ends the suction stroke, and shifts to an ascending process while moving from the bottom dead center to the top dead center. The volume of the pressurizing chamber 11 decreases as the plunger 2 moves upward in the ascending process. In this state, the fuel once sucked into the pressurizing chamber 11 flows again through the intake port 36 in the valve-opened state. Since it returns to the path 10c (suction passage 30a), the pressure in the pressurizing chamber 11 does not increase. This process is called a return process.

  At this time, the suction valve 39 generates a force in the valve opening direction due to the difference between the biasing force by the anchor spring 34 and the biasing force by the suction valve spring 38 and when the fuel flows backward from the pressurizing chamber 11 to the low-pressure fuel flow path 10c. The force in the valve closing direction due to the fluid force that works. In order to keep the suction valve 39 open during the return process, the difference between the biasing forces of the anchor spring 34 and the suction valve spring 38 is set larger than the fluid force.

  In this state, the electromagnetic coil 52 is energized by an energization command to the electromagnetic coil 52 from the ECU 27. At this time, a magnetic attractive force attracting each other is generated between the core 33 and the anchor 31b. When this magnetic attractive force becomes stronger than the urging force of the anchor spring 34, the anchor 31b starts to move in the valve closing direction.

  Although the anchor 31b and the rod 31a are separate bodies, when the anchor 31b starts moving in the valve closing direction, the anchor 31b is caught by the stopper portion 31f of the rod 31a, and the anchor 31b starts moving in the valve closing direction together with the rod 31a. When the anchor 31b collides with the core 33, the movement of the anchor 31b stops, and a collision sound is generated by the kinetic energy of the anchor 31b. Since the anchor 31b and the rod 31a are slidably held by the anchor sliding portion 31e, the rod 31a continues to move in the valve closing direction even after the anchor 31b collides with the core 33 and stops moving. The spring 34 absorbs the kinetic energy and stops the movement. Therefore, the kinetic energy of the rod 31a does not contribute to the sound. By setting it as the above structures, the sound by the collision with the core 33 can be made small.

  As described above, when the anchor 31b and the rod 31a move in the valve closing direction, only the biasing force by the suction valve spring 38 acts on the suction valve 39. Therefore, the suction valve 39 is moved in the valve closing direction by the urging force of the suction valve spring 38 and comes into contact with the suction valve seat portion 32a so as to be closed, so that the suction port 36 is closed.

  When the suction port 36 is closed, the fuel pressure in the pressurizing chamber 11 increases as the plunger 2 moves upward. When the pressure in the discharge joint 12 becomes equal to or higher than that, the high-pressure fuel remaining in the pressurizing chamber 11 is discharged via the discharge valve unit (discharge valve mechanism) 8 and supplied to the common rail 23. This process is called a discharge process. That is, the raising process of the plunger 2 includes a returning process and a discharging process.

In the discharge stroke, energization of the electromagnetic coil 52 can be canceled after the supply of pressurized fuel is started. This is because when the pressure in the pressurizing chamber 11 becomes equal to or higher than the pressure in the discharge joint 12, a force acts on the suction valve 39 in the valve closing direction due to the pressure in the pressurizing chamber 11. This is because it becomes larger than the force in the valve opening direction due to the difference in the urging force by the suction valve spring 38. Thereby, the power consumption in the electromagnetic coil 52 can be suppressed.

  The amount of high-pressure fuel that is discharged can be controlled by controlling the timing of energizing the electromagnetic coil 52 of the electromagnetic intake valve 30. If the timing of energizing the electromagnetic coil 52 is advanced, the ratio of the return process is small and the ratio of the discharge process is large during the ascending process. That is, the amount of fuel returned to the low pressure fuel flow path 10c (suction passage 30a) is small, and the amount of fuel discharged at high pressure is large.

  On the other hand, if the timing of energizing the electromagnetic coil 52 is delayed, the ratio of the return process during the ascending process is large and the ratio of the discharge process is small. That is, the amount of fuel returned to the low pressure fuel flow path 10c is large, and the amount of fuel discharged at high pressure is small. The timing of energizing the electromagnetic coil 52 is controlled by a command from the ECU 27.

  When the plunger 2 finishes the ascending process and starts the suction stroke, the volume of the pressurizing chamber 11 starts to increase again, and the pressure in the pressurizing chamber 11 decreases. Then, the fuel flows into the pressurizing chamber 11 from the low pressure fuel flow path 10c through 30a. The suction valve 39 starts to open to the left in the figure due to the difference in urging force between the anchor spring 34 and the suction valve spring 38, moves by the stroke, and then collides with the suction valve holder 35 to stop the movement. This collision occurs due to a difference in urging force between the anchor spring 34 and the suction valve spring 38, and the collision energy is not so great. For this reason, high hardness is not required in this collision portion. For this reason, in this embodiment, austenitic stainless steel is adopted as the material of the suction valve holder 35. At this time, the anchor 31b is caught by the stopper portion 31f of the rod 31a and performs valve opening motion together with the rod 31a.

  By configuring as 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 timing of energizing the electromagnetic coil 52.

  At this time, the suction valve 39 repeats the movement of the movable part 31 in the left-right direction in the figure as the plunger 2 moves downward and upward, and the suction port 36 repeats the opening and closing movement. Since there is a minute clearance between the anchor 31b of the movable part 31 and the rod 31a and between the rod 31a and the valve seat 32, the movable part 31 restricts this movement only in the direction of valve opening / closing movement. It is slidably held and repeats sliding movement. The clearance between the two sliding portions is set as follows. If the clearance is too large, the rod 31a and the anchor 31b will move in directions other than the valve opening / closing direction. As a result, the responsiveness of the valve opening / closing movement becomes poor, and the opening / closing of the intake valve 39 does not follow when the internal combustion engine operates at high speed (when the cam rotates at high speed). It becomes impossible to control the amount. Therefore, the clearance must be set to an appropriate value.

  Further, the anchor sliding portion 31e and the sliding portion 32d need to have a sufficiently low surface roughness so as not to become resistance to the valve opening motion / valve closing motion of the movable portion 31. Further, since high hardness is required from the viewpoint of durability, the materials of the suction valve 39, the valve seat 32, and the rod 31a are made of martensitic stainless steel having high hardness. It is known that martensitic stainless steel, which is a material of the rod 31a and the valve seat 32, is a magnetic material that generates a magnetic flux when placed in a magnetic field. Therefore, the flow of magnetic flux is also generated in the rod 31a and the valve seat 32 through the anchor 31b, and a magnetic attractive force attracting each other is generated. However, in the structure of the present embodiment, most of the magnetic flux passes only through the magnetic attraction surface S of the anchor 31b and the core 33, so that the suction valve 39 cannot be closed.

  Further, if the movable portion 31 repeats the valve opening motion and the valve closing motion, the rod 31a enters and exits the inner cylindrical portion of the core 33, and the fuel volume in the inner cylindrical portion of the core 33 increases or decreases. Since the inner cylindrical portion of the core 33 is filled with fuel, when the rod 31a enters and exits the inner cylindrical portion of the core 33, the fuel pushed away by the rod 31a passes through the guide portion 32d of the valve seat 32 in the left and right directions in the figure. Must go back and forth in the direction. However, the clearance between the guide portion 32d of the valve seat 32 and the rod 31a is very small, and sufficient fuel cannot pass therethrough, thereby hindering the responsiveness of the movable portion 31 to the valve opening motion / valve closing motion. Therefore, a communication hole 32e is provided in the valve seat 32.

  The volume of the space in the cylindrical portion constituted by the inner peripheral surface of the anchor 31b and the inner peripheral surface of the core 33 also increases or decreases as the movable portion 31 opens and closes. If the anchor 31b and the core 33 collide, the space in the cylindrical portion is completely sealed, and a pressure drop occurs at the moment when the anchor 31b moves away from the core 33 and shifts to the valve opening motion. There was a problem that the valve opening movement became unstable. Therefore, the anchor communication hole 31d is provided in the anchor 31b. By adopting such a structure, it is possible to facilitate the passage of fuel and to ensure the responsiveness of the opening and closing movements of the movable portion 31.

  The electromagnetic coil 52 is configured by winding a lead wire 54 around the axis of the movable portion 31. Both ends of the lead wire 54 are welded to the terminal 56 at lead wire welds 55. The terminal is a conductive substance and is open to the connector portion 58. When a mating connector from the ECU 27 is connected to the connector portion 58, the terminal contacts the mating terminal and transmits current to the electromagnetic coil 52.

  In this embodiment, the lead wire welded portion 55 is disposed outside the yoke 51. The lead wire welded portion 55 is disposed outside the magnetic circuit, and since there is no space required for the lead wire welded portion 55, the entire length of the magnetic circuit can be shortened, and sufficient magnetism is provided between the core 33 and the anchor 31b. Generation of suction force became possible.

  During the three strokes of the intake stroke, the return stroke, and the discharge stroke, fuel constantly enters and exits the intake passage 30a (low-pressure fuel flow path 10c), so that periodic pulsation occurs in the fuel pressure. This pressure pulsation is absorbed and reduced by the pressure pulsation reducing mechanism 9, blocking the propagation of the pressure pulsation from the feed pump 21 to the suction pipe 28 to the pump body 1, preventing damage to the suction pipe 28, etc., and stable. It is possible to supply fuel to the pressurizing chamber 11 with fuel pressure. Since the low pressure fuel flow path 10b is connected to the low pressure fuel flow path 10c, the fuel spreads on both sides of the pressure pulsation reducing mechanism 9 and effectively suppresses the pressure pulsation of the fuel.

  The pressure pulsation reducing mechanism 9 is composed of two metal diaphragms, and the outer periphery is fixed to each other by welding at the welded portion in a state where gas is sealed in the space between the two diaphragms. When the low pressure pulsation is loaded on both sides of the pressure pulsation reducing mechanism 9, the pressure pulsation reducing mechanism 9 changes its volume, thereby reducing the low pressure pulsation.

  The plunger 2 includes a large-diameter portion 2 a that slides with the cylinder 6 and a small-diameter portion 2 b that slides with the plunger seal 13. The diameter of the large diameter portion 2a is set larger than the diameter of the small diameter portion 2b, and is set coaxially with each other. An annular low pressure seal chamber 10f exists between the lower end of the cylinder 6 and the plunger seal 13, and the annular low pressure seal chamber 10f provided in the cylinder holder 7 through the low pressure fuel passages 10d and 10e and the annular low pressure passage 10h is a low pressure fuel. It is connected to the flow path 10c. Since the stepped portion 2c of the large diameter portion 2a and the small diameter portion 2b exists in the annular low pressure seal chamber 10f, when the plunger 2 repeats sliding motion in the cylinder 6, the step between the large diameter portion 2a and the small diameter portion 2b is performed. The attached portion repeatedly moves up and down in the annular low pressure seal chamber 10f, and the volume of the annular low pressure seal chamber 10f changes. In the intake stroke, the volume of the annular low pressure seal chamber 10f decreases, and the fuel in the annular low pressure seal chamber 10f flows through the low pressure fuel passages 10d and 10e to the low pressure fuel passage 10c. In the return stroke and the discharge stroke, the volume of the annular low pressure seal chamber 10f increases, and the fuel in the low pressure fuel passage 10d flows through the low pressure fuel passage 10e to the annular low pressure seal chamber 10f.

  Focusing on the low-pressure fuel flow path 10c, in the intake stroke, fuel flows from the low-pressure fuel flow path 10c into the pressurizing chamber 11, while fuel flows from the annular low-pressure seal chamber 10f into the low-pressure fuel flow path 10c. In the return stroke, the fuel flows from the pressurizing chamber 11 into the low pressure fuel passage 10c, while the fuel flows from the low pressure fuel passage 10c into the annular low pressure seal chamber 10f. In the discharge stroke, the fuel flows from the low pressure fuel flow path 10c into the annular low pressure seal chamber 10f. As described above, the annular low pressure seal chamber 10f has an effect of assisting fuel in and out of the low pressure fuel flow path 10c, and therefore has an effect of reducing pressure pulsation of the fuel generated in the low pressure fuel flow path 10c.

  From here, the discharge joint welding part 110 for supplying high pressure fuel to the common rail 23 from the pressurization chamber 11 is demonstrated in detail. As shown in FIG. 6, the discharge joint welded portion 110 has a gap formed on the opposite side of the pump body 1, the discharge joint 12 and their press-fit portions 110b, the welding laser receiving portion 110a, and the portion of the discharge joint welded portion that is hit by the welding laser. Part 110c, a pump body side air gap constituting surface 1c which is a face constituting the air gap 110c, and a discharge joint side air gap constituting surface 12a. First, the discharge joint 12 is press-fitted into the pump body 1 from the left side of FIG. 6 and fixed at the press-fitting portion 110b. When press-fitting, a jig is applied at the load receiving portion 12b of the discharge joint 12 and pushed to the right side of FIG.

  After press fitting the discharge joint 12 into the pump body 1, the pump body 1 and the discharge joint 12 are coupled and fixed at the discharge joint weld 110 using laser welding. When laser welding is performed, the discharge joint weld 110 is irradiated with laser from the outside. The laser irradiation direction is not only the direction orthogonal to the discharge joint weld 110 but also one of the pump body 1 and the discharge joint 12. It includes the case of irradiation from the direction inclined to the side.

  By separating the pump body 1 and the discharge joint 12 as in the present embodiment, the shape and the overall length of the discharge joint are more flexible than when the pump body 1 and the discharge joint 12 are manufactured integrally. It becomes possible to correspond to the layout of each engine.

  The discharge joint weld 110 is repeatedly loaded with internal pressure by high pressure fuel passing through the discharge joint. The fatigue strength of the discharge joint weld 110 needs to be greater than or equal to this internal pressure. To that end, the penetration depth of the discharge joint weld 110 may be increased. However, since it is necessary to increase the output of the laser used for welding in order to increase the penetration depth, it is necessary to set an appropriate value from the viewpoint of required fatigue strength and laser output.

  The gap 110c determines the penetration depth of the discharge joint weld 110, prevents the stress concentration at the discharge joint weld 110, and distributes the stress evenly throughout the weld. It is provided on the opposite side (discharge joint inner diameter side) from the receiving part 110a.

  However, if a notch shape is generated in the gap portion 110c, stress concentration occurs in that portion. Therefore, even if the penetration depth of the discharge joint weld 110 is increased, the fatigue strength does not improve as expected. Occur. As shown in FIG. 8, in the high-pressure fuel supply pump including the first member (pump body 1) and the second member (discharge joint 12) facing one surface of the first member (pump body 1), The case where the discharge joint welding part 110 which fixes a member (pump body 1) and a 2nd member (discharge joint 12) is provided is demonstrated. At this time, a gap 110c formed by the discharge joint weld 110, the first member (pump body 1), and the second member (discharge joint 12) on the opposite side of the welding portion of the discharge joint weld 110 by the welding laser, Is provided. And both the space | gap structure surface 1c of the 1st member (pump body 1) which comprises the space | gap part 110c, and the space | gap structure surface 12a of the 2nd member (discharge joint 12) are with respect to the penetration width of the discharge joint welding part 110. Are arranged so as to almost overlap. In this case, if the discharge joint weld 110 and the gap constituting surface 1c of the first member (pump body 1) intersect at an acute angle, the gap constituting surface 12a of the second member (discharge joint 12) intersects at an acute angle. There is a risk of stress concentration at the intersection.

  This problem is that the pump body-side gap forming surface 1c and the discharge joint-side gap forming surface 12a are formed substantially on the same line with respect to the weld penetration width of the discharge joint weld 110 or at a position where the lateral distance is very close. Occurs when Further, in this situation, when the discharge joint weld 110 is irradiated with a laser from a direction inclined to one of the pump body 1 and the discharge joint 12, the possibility that a notch shape is generated is further increased.

  FIG. 6 shows the case where there is no step on the gap side between the pump body and the discharge joint that are welded by laser. However, due to the processing of parts, the pump body and the discharge joint are shown in FIG. It is also assumed that there is a step on the air gap side on the opposite surface. Also in this case, there is a high possibility that a notch shape occurs after the discharge joint weld 110 is welded.

  Therefore, in the present embodiment, the discharge joint weld 110 for fixing the first member (pump body 1) and the second member (discharge joint 12), and the welded part (welding laser receiver) of the discharge joint weld 110 by the welding laser. 110a) and a gap 110c formed by the discharge joint weld 110, the first member (pump body 1), and the second member (discharge joint 12). At least one of the air gap constituting surface 1c of the first member (pump body 1) and the air gap constituting surface 12a of the second member (discharge joint 12) constituting the air gap portion 110c corresponds to the penetration width of the discharge joint welded portion 110. And formed outside. Thereby, since notch shape does not generate | occur | produce in the discharge joint welding part 110, when increasing the penetration depth of the discharge joint welding part 110, it becomes possible to obtain desired fatigue strength. As shown in FIG. 6, both the gap forming surface 1 c of the first member (pump body 1) and the gap forming surface 12 a of the second member (discharge joint 12) constituting the gap 110 c are the discharge joint welded portions 110. In order to obtain a desired fatigue strength, it is desirable to form the outer side with respect to the melt penetration width.

  More specifically, as shown in FIG. 6, the second member (discharge joint 12) on the opposite side of the outer peripheral portion of the first member (pump body 1) from the welding site (welding laser receiving portion 110 a) by the welding laser. The inner periphery is press-fitted, and the outer periphery of the first member (pump body 1) forms part of the gap 110c. In addition, the welding direction of the discharge joint welding part 110 is the 1st member (pump body 1) or 2nd member (discharge) with respect to the opposing part of a 1st member (pump body 1) and a 2nd member (discharge joint 12). It may be formed inclined to one side of the joint 12). At this time, on the inclined side, the direction in which the facing portion is formed and the welding direction of the welded portion may be configured to have an acute angle.

  Moreover, as shown in FIG. 7, you may comprise so that there may be a level | step difference in the space | gap side in the opposing part of the 1st member (pump body 1) and 2nd member (discharge joint 12) by a welding laser. Specifically, among the facing portions of the first member (pump body 1) and the second member (discharge joint 12) by the welding laser, the facing surface of the press-fitting second member (discharge joint 12) is the first. It comprises so that it may become long in the space | gap side rather than the opposing surface of a member (pump body 1).

  The gap portion 110c intersects the gap constituting surface 1c of the first member (pump body 1) from the gap constituting surface 1c of the first member (pump body 1) formed outside the penetration width of the discharge joint weld 110. It is good to be comprised with the crossing surface which goes to the discharge joint welding part 110 in the direction to do. It is preferable that the air gap forming surface 1c and the intersecting surface are configured to be substantially orthogonal to each other.

  Similarly, the gap portion 110c is formed between the gap forming surface 12a of the second member (discharge joint 12) formed on the outer side with respect to the penetration width of the discharge joint welded portion 110 and the gap forming surface of the second member (discharge joint 12). It is good to be comprised by the crossing surface which goes to the discharge joint welding part 110 in the direction which cross | intersects 12a. It is preferable that the gap forming surface 12a and the intersecting surface be configured to be substantially orthogonal. As a result, stress concentration caused by crossing at an acute angle can be avoided, so that a desired fatigue strength can be obtained.

  The stress concentration is caused by a high-pressure fuel of 20 MPa or more flowing on the opposite side (inside the pump body and the discharge joint) to the portion of the discharge joint weld 110 where the welding beam hits. However, according to the high pressure fuel supply pump of the present embodiment, stress concentration occurring in the discharge joint weld 110 can be avoided even when such high pressure fuel flows, and a desired fatigue strength can be obtained. . In this embodiment, the first member (pump body 1) and the second member (discharge joint 12) have been described as an example. Similarly, when the members through which high-pressure fuel flows are welded to each other, the same problem occurs. This problem can be solved by the configuration of this embodiment.

1 Pump Body 1a Pump Body Crimping Surface 1b Pump Body Threaded Part 1c Discharge Joint Welded Part Inside Vapor Construction Surface (Pump Body Side)
1A Pump body recessed portion 1B Clearance 2 Plunger 2a Large diameter portion 2b Small diameter portion 3 Tappet 5 Cam 6 Cylinder 7 Cylinder holder 8 Discharge valve unit 9 Pressure pulsation reduction mechanism 10a Low pressure fuel inlet 10b, 10c Low pressure fuel flow path 10d, 10e Low pressure Fuel passage 10f Annular low pressure seal chamber 11 Pressurization chamber 12 Discharge joint 12a Discharge joint welded portion inner side void forming surface (discharge joint side)
13 Plunger seal 20 Fuel tank 21 Feed pump 23 Common rail 24 Injector 26 Pressure sensor 27 Engine control unit (ECU)
30 Electromagnetic suction valve 31 Movable part 31a Rod 31b Anchor 31c Anchor inner circumference 31d Anchor communication hole 31e Anchor sliding part 32 Valve seat 33 Core 34 Anchor spring 35 Suction valve holder 38 Suction valve spring 39 Suction valve 52 Electromagnetic coil 110 Discharge joint welding 110a Discharge joint welding laser receiving part 110b Discharge joint press-fitting part 110c Discharge joint welding part inner side gap part

Claims (10)

In a high-pressure fuel supply pump comprising a first member and a second member facing one surface of the first member,
A welding portion for fixing the first member and the second member;
A gap formed by the welded portion, the first member, and the second member on the opposite side of the welded portion of the welded portion by the welding laser,
A high-pressure fuel supply pump in which at least one of a gap constituting surface of the first member and a gap constituting surface of the second member constituting the gap is formed outside with respect to a penetration width of the welded portion. In a high-pressure fuel supply pump comprising a first member and a second member facing one surface of the first member,
A welding portion for fixing the first member and the second member;
A gap formed by the welded portion, the first member, and the second member on the opposite side of the welded portion of the welded portion by the welding laser,
The high-pressure fuel supply pump in which both the gap forming surface of the first member and the gap forming surface of the second member that form the gap are formed outside the penetration width of the welded portion. The high-pressure fuel supply pump according to claim 1 or 2,
The inner peripheral portion of the second member on the opposite side of the welding portion by the welding laser is press-fitted with respect to the outer peripheral portion of the first member, and the outer peripheral portion of the first member forms part of the gap. A high-pressure fuel supply pump. The high-pressure fuel supply pump according to claim 1 or 2,
The welding direction of the welded portion is formed to be inclined to one side of the first member or the second member with respect to the facing portion of the first member and the second member,
A high-pressure fuel supply pump characterized in that, on the inclined side, the direction in which the facing portion is formed and the welding direction of the welded portion form an acute angle. The high-pressure fuel supply pump according to claim 1 or 2,
A high-pressure fuel supply pump characterized in that there is a step on the air gap side at the facing portion between the first member and the second member by a welding laser. The high-pressure fuel supply pump according to claim 1 or 2,
Of the facing portions between the first member and the second member by the welding laser, the facing surface of the second member on the press-fitting side is configured to be longer on the gap side than the facing surface of the first member. A high-pressure fuel supply pump characterized by that. The high-pressure fuel supply pump according to claim 1 or 2,
The gap is constituted by an intersecting surface that faces the welded portion in a direction intersecting with the void constituting surface of the first member from the void constituting surface of the first member formed outside the penetration width of the welded portion. A high-pressure fuel supply pump characterized by that. The high-pressure fuel supply pump according to claim 1 or 2,
The gap is constituted by an intersecting surface that faces the welded portion in a direction intersecting with the void constituting surface of the second member from the void constituting surface of the second member formed outside the penetration width of the welded portion. A high-pressure fuel supply pump characterized by that. The high-pressure fuel supply pump according to any one of claims 1 to 5,
The high-pressure fuel supply pump, wherein the first member is a pump body forming a pressurizing chamber, and the second member is a discharge joint press-fitted into the pump body. The high-pressure fuel supply pump according to any one of claims 1 to 5,
The first member is a pump body forming a pressurizing chamber; the second member is a discharge joint press-fitted into the pump body;
A high-pressure fuel supply pump, characterized in that high-pressure fuel flows on the opposite side (inside the pump body and discharge joint) of the welded portion to which the welding beam hits.

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