JP2018031332A - High pressure fuel supply pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure fuel supply pump which deals with increase of pressure and a flow rate and high viscosity fuels and achieves high reliability, specifically, to provide a mechanism which enables improvement of filter strength.MEANS FOR SOLVING THE PROBLEM: A high pressure fuel supply pump includes: a compression chamber for compressing a fuel; a low pressure fuel chamber formed at the upstream side of the compression chamber; and a suction joint attached to the upstream side of the low pressure fuel chamber. The high pressure fuel supply pump includes a filter attached to a cylindrical part located at the inner periphery side of the suction joint. The filter is formed by a cup-shaped metal plate, and multiple holes are formed on the metal plate by punch processing and laser processing.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a high-pressure fuel supply pump, and particularly to a fuel filter made of a metal plate.

  There exists patent document 1 (patent publication 2010-151142) as a prior art of this invention. In FIG. 5 and paragraph 0023 of Patent Document 1, “the fuel is led from the discharge passage 11 through the cross hole 11b to the communication passage 105. The relief assembly 102 is opened when the pressure exceeds a predetermined pressure. It is provided with a check valve 102a and a valve seat 102d to be valved, and is formed from a plug 301 that closes the open end of the communication passage 105. It also has a fuel filter 320 that removes fuel impurities inside. " There is.

Japanese Patent Publication No. 2010-151142

  In the above-mentioned patent document, for example, when a metal mesh having a filter structure is employed, there are the following problems. That is, when the fuel is at a high pressure and high flow rate, or when a block of frozen fuel blocks the filter flow path, or when high-viscosity fuel is used, the force exceeds the allowable stress of the filter. May be loaded on the filter and the filter may be damaged.

  Accordingly, an object of the present invention is to provide a high-pressure fuel supply pump having high reliability even when the fuel has a high pressure and a high flow rate, or in the above case.

  In order to solve the above problems, the present invention provides a pressurizing chamber for pressurizing fuel, a low-pressure fuel chamber formed on the upstream side of the pressurizing chamber, and a suction joint attached on the upstream side of the low-pressure fuel chamber. The high-pressure fuel supply pump includes a filter attached to a cylindrical portion on the inner peripheral side of the suction joint, and the filter is formed of a cup-shaped metal plate, and has a plurality of holes in the metal plate. Was formed by punching or laser processing.

The high-pressure fuel supply pump according to the present invention can provide a highly reliable high-pressure fuel supply pump even when the fuel has a high pressure and a high flow rate, or in the above case.
Other configurations, operations, and effects of the present invention will be described in detail in the following examples.

1 is an example of a fuel supply system using 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 a longitudinal cross-sectional view of the high pressure fuel supply pump by 1st Example with which this invention was implemented, and represents a cross section perpendicular | vertical to FIG. The expansion part of the filter part of the high-pressure fuel supply pump by the 1st example with which the present invention was implemented is shown. It is an enlarged view of the electromagnetic suction valve mechanism 30 of the high-pressure fuel supply pump according to the first embodiment in which the present invention is implemented, and shows a state where the electromagnetic coil 52 is not energized. It is an enlarged view of the electromagnetic suction valve mechanism 30 of the high-pressure fuel supply pump according to the first embodiment in which the present invention is implemented, and shows a state where the electromagnetic coil 52 is energized. It is an enlarged view of the electromagnetic suction valve mechanism 30 of the conventional high-pressure fuel supply pump, and shows a state where the electromagnetic coil 52 is not energized. FIG. 3 shows a state before the electromagnetic suction valve mechanism 30 of the high-pressure fuel supply pump according to the first embodiment in which the present invention is implemented is assembled in the pump housing 1. The external view of the flange 41 of the high-pressure fuel supply pump by the 1st Example by which this invention was implemented, and the bush 43 is shown. In this figure, only the flange 41 and the bush 43 are shown, and other components are not shown. The enlarged view of the welding part 41a part vicinity of the high-pressure fuel supply pump by the 1st Example by which this invention was implemented is shown. The enlarged view of the welding part 41a vicinity vicinity of the high-pressure fuel supply pump by 1st Example by which this invention was implemented is shown, and it expands rather than FIG. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 2nd Example by which this invention was implemented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  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 housing 1 of the high-pressure fuel supply pump, and the mechanisms and components shown in the broken line are integrated into the pump housing 1 of the high-pressure fuel supply pump. Indicates that

  The fuel in the fuel tank 20 is pumped up by a low pressure fuel supply pump 21 based on a signal from an engine control unit 27 (hereinafter referred to as ECU), pressurized to an appropriate feed pressure, and sucked into the high pressure fuel supply pump through a suction pipe 28. It is sent to the mouth 10a. The fuel that has passed through the suction port 10a passes through a filter 102 fixed in the suction joint 101, and further, an electromagnetically driven type that constitutes a variable capacity mechanism via the suction flow path 10b, the metal diaphragm damper 9, and the low-pressure fuel chamber 10c. It reaches the suction port 30a of the valve mechanism 30. The suction filter 102 in the suction joint 101 serves to prevent foreign matter existing between the fuel tank 20 and the suction port 10a from being absorbed into the high-pressure fuel supply pump by the flow of fuel.

  FIG. 4 is an enlarged view of the filter 102 and is shown in a state of being fixed in the suction joint 101. As shown in FIG. 3, the high-pressure fuel supply pump of the present embodiment includes a pressurizing chamber 11 that pressurizes fuel, low-pressure fuel chambers (10b, 10c) formed on the upstream side of the pressurizing chamber 11, and a low-pressure fuel chamber. And a suction joint 101 attached to the upstream side of (10b, 10c).

The filter 102 has a structure in which a metal plate (thickness t102) is cup-shaped, and a plurality of holes 102A are formed in a cylindrical side surface portion by laser processing so that foreign matters larger than the hole diameter d102 do not pass through. . Specifically, the filter 102 is attached to the cylindrical portion (small diameter cylindrical portion 101a, large diameter cylindrical portion 101b) on the inner peripheral side of the suction joint 101. The filter 102 is formed of a cup-shaped metal plate, and a plurality of holes are formed in the metal plate by punching or laser processing.
In other words, in this embodiment, the filter 102 is configured by using a punching mesh that is manufactured by making a hole in a metal plate, instead of a metal mesh that forms a wire mesh by weaving metal bar wires.

  Recent high-pressure fuel pumps are required to supply high-pressure fuel such as 35 MPa, and the required flow rate is also increasing. As a result, when a metal mesh filter is used, the load on the filter is large, which may cause damage. Alternatively, there is a risk of damage in the same manner when frozen fuel blocks block the filter flow path or when high-viscosity fuel is used. The present inventors have found a problem peculiar to this high-pressure fuel supply pump, and in order to solve this problem, the filter 102 is configured using a punching mesh as described above.

  In the filter 102, a portion 102a that functions as a filter by making a hole in a cylindrical portion having a small outer diameter by laser processing and a portion 102b that functions to fix the filter 102 to the suction joint 101 in a cylindrical portion having a large outer diameter are integrated. Configured to be a structure. That is, the filter 102 includes a cylindrical portion having a small outer diameter (filter small diameter portion 102a) in which a plurality of holes are formed, and a cylindrical portion having a large outer diameter (filter large diameter portion 102b) for fixing the filter 102 to the suction joint 101. Are constituted by an integral structure. The outer periphery of the cylindrical portion of the filter 102 (filter large diameter portion 102b) is press-fitted into the inner peripheral portion of the cylindrical portion of the suction joint 101 (large diameter cylindrical portion 101b), whereby the filter 102 is fixed to the suction joint 101. The Thereby, it has the structure which reduces the influence which the distortion which arises when opening 102A of holes by laser processing is transmitted to the fitting part (filter large diameter part 102b) with the suction joint 101. FIG.

  The fitting portion 102b of the filter 102 with the suction joint 101 is brought into metal contact with the large-diameter cylindrical portion 101b on the inner peripheral side of the suction joint by press-fitting and fixing, so that there is no gap between the filter 102 and the suction joint, and foreign matter is low-pressure fuel. Inflow to the chamber 10c is prevented. A fuel passage 101c is formed at the inlet of the inner peripheral cylindrical portion of the suction joint 101, and a small-diameter cylindrical portion 101a having an inner diameter smaller than that of the fuel passage 101c is formed on the downstream side of the fuel passage 101c. The inner peripheral side of the suction joint 101 is formed by an inlet fuel passage 101c, a large-diameter cylindrical portion 101b on the downstream side thereof, and a small-diameter cylindrical portion 101a on the further downstream side. Further, a connecting portion (step portion) is formed between the large-diameter cylindrical portion 101b and the small-diameter cylindrical portion 101a.

  On the other hand, the filter 102 is formed with a connecting portion (step portion) that connects the filter large diameter portion 102b and the filter small diameter portion 102a. The connection portion (step portion) of the suction joint 101 is configured to receive the connection portion (step portion) of the filter 102 in the axial direction of the suction joint. In other words, the filter 102 is configured integrally with a filter large-diameter portion 102b on the fuel inlet side and a filter small-diameter portion (102a) on the low-pressure fuel chamber (10b, 10c) side. The filter 102 is prevented from moving to the low pressure fuel chamber 10c side. In this way, when the filter is configured in two stages and the filter large-diameter portion 102b is press-fitted, distortion that occurs when a filter hole is formed in the filter small-diameter portion 102a by laser processing causes a fitting portion of the suction joint. The influence transmitted to the (press-fit part) can be reduced.

The large-diameter portion 102b of the filter 102 and the press-fit portion (contact portion) of the large-diameter cylindrical portion 101b of the suction joint 101 are brought into metal contact. Thereby, the foreign matter mixed in the low pressure fuel pumped from the low pressure fuel pump 21 is sealed. When the filter 102 is inserted into the suction joint 101, the filter 102 is attached so that the convex portion is directed toward the low-pressure fuel chamber 10c. Thereby, the full length of the suction joint 101 can be shortened.
In the present embodiment, the suction joint 101 is configured separately from the pump housing 1, but it may be configured integrally. That is, the suction joint 101 may be formed by a hole formed in the pump housing 1, and the filter 102 may be directly attached to the hole of the pump housing 1.

  FIG. 5 is an enlarged view of the electromagnetic intake valve mechanism 30, and shows a non-energized state where the electromagnetic coil 53 is not energized. FIG. 6 is an enlarged view of the electromagnetic intake valve mechanism 30, and shows a state where the electromagnetic coil 53 is energized. The pump housing 1 is formed with a convex portion 1A for accommodating the cylinder 6 including the pressurizing chamber 11 at the center, and a hole 30A for mounting the electromagnetic suction valve mechanism 30 is formed so as to open to the pressurizing chamber 11. Has been.

  The plunger rod 31 includes three portions, that is, a suction valve portion 31a, a rod portion 31b, and an anchor fixing portion 31c. An anchor 35 is welded and fixed to the anchor fixing portion 31c by a welding portion 37b. As shown in the figure, the spring 34 is fitted into the anchor inner periphery 35a and the first core portion inner periphery 33a, and a spring force is generated by the spring 34 in a direction in which the anchor 35 and the first core portion 33 are separated.

  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 first core portion 33. The suction valve seat portion 32a is press-fitted and fixed to the pump housing 1, and the pressurization chamber 11 and the suction port 30a are completely blocked by this press-fit portion. The first core portion 33 is welded and fixed to the pump housing 1 by a welded portion 37c, and shuts off the suction port 30a and the outside of the high-pressure fuel supply pump.

  The 2nd core part 36 is being fixed to the 1st core part 33 by the welding part 37a, and has interrupted | blocked the internal space and external space of the 2nd core part 36 completely. The second core portion 36 is provided with a magnetic orifice portion 36a. When the electromagnetic coil 53 is not energized and is not energized, and when there is no fluid differential pressure between the suction channel 10c (suction port 30a) and the pressurizing chamber 11, the plunger rod 31 is As shown in FIG. 4, it moves to the right in the figure. In this state, the intake valve portion 31a and the intake valve seat portion 32a come into contact with each other and the intake port 38 is closed.

  When the plunger 2 is in the suction process state where the plunger 2 is displaced downward in FIG. 2 due to the rotation of the cam 5 described later, the volume of the pressurizing chamber 11 increases and the fuel pressure in the pressurizing chamber 11 decreases. When the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure in the low pressure fuel chamber 10c (suction port 30a) in this step, the valve opening force (suction valve portion 31a) due to the fluid differential pressure of the fuel is shown in the suction valve portion 31a. 3) is generated.

  By the valve opening force due to the fluid differential pressure, the suction valve portion 31a is set to open over the biasing force of the spring 34 and open the suction port 38. When the fluid differential pressure is large, the suction valve portion 31 a is completely opened and the anchor 31 is in contact with the first core portion 33. When the fluid differential pressure is small, the suction valve portion 31 a does not open completely, and the anchor 31 does not contact the first core portion 33.

  In this state, when a control signal from the ECU 27 is applied to the electromagnetic intake valve mechanism 30, a current flows through the electromagnetic coil 53 of the electromagnetic intake valve mechanism 30, and between the first core portion 33 and the anchor 31, Magnetic biasing forces that attract each other are generated. As a result, a magnetic urging force is applied to the plunger rod 31 to the left in the drawing.

When the intake valve portion 31a is completely open, the valve open state is maintained. On the other hand, when the intake valve portion 31a is not fully opened, the intake valve portion 31a is fully opened by encouraging the valve opening motion of the intake valve portion 31a, so that the anchor 31 is in contact with the first core portion 33, Then maintain that state.
As a result, the state where the suction valve portion 31a opens the suction port 38 is maintained, and the fuel flows from the suction port 30a through the suction passage portion 32b of the valve seat 32 and the suction port 38 into the pressurizing chamber 11. When the plunger 2 finishes the suction process while the application state of the input voltage is maintained in the electromagnetic suction valve mechanism 30 and the plunger 2 moves to the compression process in which the plunger 2 is displaced upward in FIG. 2, the magnetic urging force remains maintained. The suction valve portion 31a is still open.

  Although the volume of the pressurizing chamber 11 decreases as the plunger 2 compresses, in this state, the fuel once sucked into the pressurizing chamber 11 passes through the suction port 38 in the valve-opened state again, and the suction flow path 10c (suction). Since the pressure is returned to the port 30a), the pressure in the pressurizing chamber does not increase. This process is called a return process.

  In this state, when the control signal from the ECU 27 is canceled and the electromagnetic coil 53 is de-energized, the magnetic biasing force acting on the plunger rod 31 is after a certain time (after magnetic and mechanical delay time). Erased. Since the urging force of the spring 34 is acting on the suction valve portion 31 a, the suction valve portion 31 a closes the suction port 38 with the urging force of the spring 34 when the electromagnetic force acting on the plunger rod 31 disappears. When the suction port 38 is closed, the fuel pressure in the pressurizing chamber 11 increases with the upward movement of the plunger 2 from this time. When the pressure in the fuel discharge port 12 or higher is reached, high pressure discharge of the fuel remaining in the pressurizing chamber 11 is performed via the discharge valve unit 8 and supplied to the common rail 23. 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 timing which cancels | releases the electricity supply to the electromagnetic coil 53 of the electromagnetic suction valve mechanism 30. FIG. If the timing of releasing the energization of the electromagnetic coil 53 is advanced, the ratio of the return process is small and the ratio of the discharge process is large during the compression process. That is, the amount of fuel returned to the suction channel 10c (suction port 30a) is small, and the amount of fuel discharged at high pressure is large.

  On the other hand, if the timing for releasing the input voltage 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 10c is large, and the amount of fuel discharged at high pressure is small. The timing for releasing the energization of the electromagnetic coil 53 is controlled by a command from the ECU 27.

  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 releasing the energization of the electromagnetic coil 53.

  Thus, the fuel guided to the fuel suction port 10 a is pressurized to a high pressure by the reciprocation of the plunger 2 in the pressurizing chamber 11 of the pump housing 1, and is pumped from the fuel discharge port 12 to the common rail 23. 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.

  At this time, the suction valve portion 31a repeats the opening / closing motion of the suction port 38 as the plunger 2 descends and ascends, and the plunger rod 31 repeats the lateral movement in the drawing. At this time, the movement of the plunger rod 31 is limited to the movement in the horizontal direction in the drawing by the sliding portion 32d of the valve seat 32, and the sliding portion 32d and the rod portion 31b repeat the sliding motion. Therefore, the sliding portion needs to have a sufficiently low surface roughness so as not to be a resistance to the sliding movement of the plunger rod 31. The selection of the sliding clearance is as follows.

  If the clearance is too large, the plunger rod 31 touches like a pendulum around the sliding portion, and the anchor 35 and the second core portion 36 come into contact with each other. If the plunger rod 31 slides, the anchor 35 and the second core portion 36 will also slide, so the resistance of the plunger rod 31 will increase, and the responsiveness of the opening / closing motion of the suction port 38 will be poor. Become. Further, since the anchor 35 and the second core portion 36 are made of ferritic magnetic stainless steel, there is a possibility that abrasion powder or the like is generated when they are slid. Furthermore, as will be described later, the smaller the gap between the anchor 35 and the second core portion 36, the greater the magnetic biasing force. If the gap is too large, the magnetic biasing force is insufficient, and the amount of fuel discharged at high pressure cannot be properly controlled. For these reasons, the gap between the anchor 35 and the second core portion 36 needs to be as small as possible and not in contact.

  Therefore, the sliding part is provided at one place, and the sliding length L of the sliding part 32d is sufficiently long as shown in the figure. The sliding portion is formed by the inner diameter of the sliding portion 32d and the outer shape of the rod portion 31b. Both of them require a tolerance, and the clearance of the sliding portion also requires a tolerance. On the other hand, the clearance between the anchor 35 and the second core portion 36 has an upper limit value based on the magnetic biasing force as described above. In order to absorb this clearance tolerance and prevent the anchor 35 and the second core portion 36 from coming into contact with each other, the sliding length L may be increased to reduce the pendulum motion.

  Thereby, when the plunger rod 31 tries to perform the pendulum motion, the sliding portion 32d and the rod portion 31b come into contact with and slide at both ends of the sliding portion, so that the gap between the anchor 35 and the second core portion 36 is reduced. It became possible.

  If the clearance is too small, the suction valve portion 31a and the suction valve seat portion 32a are not completely in surface contact when the suction port 38 is closed. This is because the verticality of the suction valve portion 31a and the rod portion 31b of the plunger rod 31 and the verticality of the suction valve seat portion 32a and the sliding portion 32d of the valve seat 32 cannot be absorbed by the clearance of the sliding portion. . If the suction valve portion 31a and the suction valve seat portion 32a are not completely in surface contact, the plunger rod 31 may be damaged due to excessive torque applied to the plunger rod 31 by the high pressure fuel in the pressurizing chamber 11 that has become high pressure during the discharge process. There is. In addition, an excessive load is applied to the sliding portion, and the sliding portion may be damaged or worn.

  For these reasons, when the suction port 38 is in the closed state, the suction valve portion 31a and the suction valve seat portion 32a need to be in complete surface contact. In particular, when the pendulum motion of the plunger rod 31 is suppressed by increasing the sliding length L as described above, the verticality of the intake valve portion 31a and the rod portion 31b of the plunger rod 31 and the intake of the valve seat 32 The accuracy required for the verticality of the valve seat portion 32a and the sliding portion 32d is increased.

  Therefore, the valve seat 32 is provided with a suction valve seat portion 32a and a sliding portion 32d. The suction valve seat portion 32a and the sliding portion 32d are made the same member so that the perpendicularity between the suction valve seat portion 32a and the sliding portion 32d can be made with high accuracy. If the suction valve seat portion 32a and the sliding portion 32d are separate members, a factor that deteriorates the squareness is inevitably generated in the parts to be processed and joined. However, the suction valve seat portion 32a and the sliding portion 32d should be made one member. This solves this problem.

  Further, if the magnetic biasing force generated when the magnetic coil 53 is energized is insufficient, the amount of fuel discharged at high pressure cannot be controlled appropriately. Therefore, the magnetic circuit constructed around the magnetic coil 53 must generate a sufficient magnetic biasing force. For this purpose, it is necessary to provide a magnetic circuit in which more magnetic flux flows when the magnetic coil 53 is energized and a magnetic field is generated around it. In general, the thicker and shorter the magnetized path, the smaller the magnetic resistance, so the magnetic flux passing through the magnetic circuit increases and the generated magnetic biasing force also increases.

  In this embodiment, the members constituting the magnetic circuit are an anchor 35, a first core portion 33, a yoke 51, and a second core portion 36 as shown in FIG. 5, and these are all magnetic materials. Although the first core portion 33 and the second core portion 36 are joined by welding by a welded portion 37a, the magnetic flux does not pass directly between the first core portion 33 and the second core portion 36, and the anchor 35 is interposed. Need to pass through. This is to generate a magnetic urging force between the first core portion 33 and the anchor 35, and the magnetic flux directly passes between the first core portion 33 and the second core portion 36, and the magnetic flux passes through the anchor. If this decreases, the magnetic biasing force will decrease.

  For this reason, in the conventional structure, an intermediate member is provided between the first core portion 33 and the second core portion 36. Since this intermediate member is a non-magnetic material, the magnetic flux does not pass directly between the first core portion 33 and the second core portion 36, and all the magnetic flux passes through the anchor 35. However, when the intermediate member is provided, the number of parts is increased, and it is necessary to join the intermediate member and the first core portion 33 and the second core portion 36, respectively.

  Therefore, in this embodiment, the first core portion 33 and the second core portion 36 are directly joined by the welded portion 37, and the magnetic orifice portion 36a is provided in the second core portion. In the magnetic orifice portion 36a, the thickness is made as thin as the strength allows, while the other portions of the second core portion 36 have a sufficient thickness. Further, the magnetic orifice portion 36a is provided in the vicinity of the portion where the first core portion and the anchor 35 are in contact with each other.

  As a result, most of the generated magnetic flux passes through the anchor 37, and the magnetic flux that passes directly through the first core portion 33 and the second core portion is very small, thereby being generated between the first core portion 33 and the anchor 35. The reduction of the magnetic urging force is within an allowable range.

  Further, when the first core portion 33 and the anchor 35 are in contact with each other, the largest gap in the magnetic circuit is between the second core portion 36 and the anchor 35. Since the gap is not a magnetic material but is filled with fuel, the larger the gap, the greater the magnetic resistance of the magnetic circuit. Therefore, the smaller the gap, the better. In the present embodiment, as described above, the gap between the second core portion 36 and the anchor 35 is reduced by increasing the sliding length L of the sliding portion.

  The magnetic coil 53 is formed by winding a lead wire 54 around the axis of the plunger rod 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 part 58. When the mating connector from the ECU 27 is connected to the connector part 58, the terminal contacts the mating terminal and transmits current to the coil.

  FIG. 7 shows a conventional structure. In the conventional structure, the lead wire welding part 55 is arrange | positioned inside the magnetic circuit. Since the lead wire welded portion 55 requires a small volume, the entire length of the magnetic circuit is increased accordingly. This increases the magnetic resistance of the magnetic circuit, and there is a problem that the magnetic urging force generated between the first core portion 33 and the anchor 35 is reduced.

  In this embodiment, the lead wire welded portion 55 is disposed outside the yoke 51. Since the lead wire welded portion 55 is arranged outside the magnetic circuit, and there is no space required for the lead wire welded portion 55, the total length of the magnetic circuit can be shortened, and the first core portion 33 and the anchor 35 are interposed. A sufficient magnetic biasing force can be generated.

  FIG. 8 shows a state before the electromagnetic suction valve mechanism 30 is assembled into the pump housing 1. In this embodiment, first, a unit is created for each of the intake valve unit 37 and the connector unit 38. Next, the suction valve seat portion 32a of the suction valve unit 37 is press-fitted and fixed to the pump housing 1, and then the welded portion 37c is welded over the entire circumference. In this embodiment, the welding is laser welding. In this state, the connector 38 is press-fitted and fixed to the first core portion 33. Thereby, the direction of the connector 58 can be freely selected.

  The pump housing 1 is formed with a convex portion 1A for accommodating the cylinder 6 including the pressurizing chamber 11 in the center, and a recess 11A for mounting the discharge valve mechanism 8 is formed so as to open to the pressurizing chamber 11. Has been.

  A discharge valve mechanism 8 is provided at the outlet of the pressurizing chamber 11. The discharge valve mechanism 8 includes a sheet member (sheet member) 8a, a discharge valve 8b, a discharge valve spring 8c, and a holding member 8d as a discharge valve stopper. The discharge valve mechanism 8 is formed by welding a welded portion 8e outside the pump housing 1. Assemble mechanism 8. Thereafter, the discharge valve mechanism 8 assembled from the left side in the figure is press-fitted and fixed to the pump housing 1. The press-fitting unit also has a function of blocking the pressurizing chamber 11 and the discharge port 12.

  In a state where there is no fuel differential pressure between the pressurizing chamber 11 and the discharge port 12, the discharge valve 8b is pressed against the seat member 8a by the urging force of the discharge valve spring 8c and is in a closed state. Only when the fuel pressure in the pressurizing chamber 11 becomes larger than the fuel pressure in the discharge port 12 by a predetermined value, the discharge valve 8b is opened against the discharge valve spring 8c, and the pressure in the pressurizing chamber 11 is increased. The fuel is discharged to the common rail 23 through the discharge port 12.

  When the discharge valve 8b is opened, the discharge valve 8b comes into contact with the holding member 8d and its operation is restricted. Therefore, the stroke of the discharge valve 8b is appropriately determined by the holding member 8d. If the stroke is too large, the fuel discharged to the fuel discharge port 12 will flow back into the pressurizing chamber 11 again due to the delay in closing the discharge valve 8b, and the efficiency of the high-pressure pump will decrease. . Further, when the discharge valve 8b repeats opening and closing movements, the holding member 8d guides the discharge valve 8b to move only in the stroke direction. By configuring as described above, the discharge valve mechanism 8 becomes a check valve that restricts the flow direction of fuel.

  The lower end of the plunger 2 is provided with a tappet 3 that converts the rotational motion of the cam 5 attached to the camshaft of the engine into vertical motion and transmits it to the plunger 2. The plunger 2 is pressure-bonded to the tappet 3 by a spring 4 through a retainer 15. The retainer 15 is fixed to the plunger 2 by press-fitting. As a result, the plunger 2 can be moved back and forth (reciprocated) up and down as the cam 5 rotates.

  Here, the low-pressure fuel chamber 10c is connected to the seal chamber 10f via the suction channel 10d and the suction channel 10e provided in the cylinder holder 7, and the seal chamber 10f is always connected to the pressure of the intake fuel. ing. When the fuel in the pressurizing chamber 11 is pressurized to a high pressure, a minute amount of high-pressure fuel flows into the seal chamber 10f through the sliding clearance between the cylinder 6 and the plunger 2, but the inflowed high-pressure fuel is released to the suction pressure. Therefore, the plunger seal 13 is not damaged by the high pressure.

  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. The sliding part with the cylinder 6 is the large diameter part 2a, and the sliding part with the plunger seal 13 is the small diameter part 2b. Thereby, since the joint part of the large diameter part 2a and the small diameter part 2b exists in the seal chamber 10f, the volume of the seal chamber 10f changes with the sliding movement of the plunger 2, and the fuel is sucked in accordingly. It moves between the seal chamber 10f and the suction channel 10c through the channel 10d and the suction channel 10s.

  Since the plunger 2 repeatedly slides with the plunger seal 13 and the cylinder 6, frictional heat is generated. This heat causes the large-diameter portion 2a of the plunger 2 to thermally expand. Of the large-diameter portion 2a, the plunger seal 13 side is closer to the heat source than the pressurizing chamber 11 side. Therefore, the thermal expansion of the large diameter portion 2a is not uniform, and as a result, the cylindricity is deteriorated, and the plunger 2 and the cylinder 6 are seized and fixed.

  In the present embodiment, the fuel in the seal chamber 10f is always replaced with the sliding movement of the plunger 2, so that this fuel has an effect of removing generated heat. As a result, deformation of the large-diameter portion 2a due to frictional heat and the seizure and adhesion of the plunger 2 and the cylinder 6 generated thereby can be prevented.

  Furthermore, since the friction area becomes smaller as the diameter of the sliding portion with the plunger seal 13 becomes smaller, the frictional heat generated by the sliding motion is also reduced. In this embodiment, since the small diameter portion 2b of the plunger 2 slides with the plunger seal 13, the amount of heat generated by friction with the plunger seal 13 can be suppressed to a small value, and seizure sticking can be prevented.

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

  The high-pressure fuel supply pump is fixed to the engine by a flange 41, a set screw 42, and a bush 43. The flange 41 is welded to the pump housing 1 by welding at a welded portion 41a. In this embodiment, laser welding is used.

  In FIG. 9, the external view of the flange 41 and the bush 43 is shown. In this figure, only the flange 41 and the bush 43 are shown, and other components are not shown. The two bushes 43 are attached to the flange 41, and are attached to the opposite side of the engine. The two set screws 42 are screwed into respective screws formed on the engine side, and the two bushes 43 and the flange 41 are pressed against the engine to fix the high pressure fuel supply pump to the engine.

  The bush 43 includes a flange portion 43a and a caulking portion 43b. First, the caulking portion 43 b is caulked and coupled to the mounting hole of the flange 41. Thereafter, the pump housing 1 and the welded portion 41a are welded together by laser welding. Thereafter, the resin fastener 44 is inserted into the bush 43, and the set screw 42 is inserted into the fastener 44. The fastener 44 serves to temporarily fix the set screw 42 to the bush 43. That is, the set screw 42 is fixed so as not to fall off the bush 43 until the high-pressure fuel supply pump is attached to the engine. When the high pressure fuel supply pump is fixed to the engine, the set screw 42 is screwed and fixed to a screw portion provided on the engine side. At that time, the set screw 42 is rotated in the bush 43 by the tightening torque of the set screw 42. it can.

  When the high-pressure fuel supply pump repeats high-pressure discharge, the pressure in the pressurizing chamber 11 repeats high pressure and low pressure as described above. When the pressurizing chamber 11 is at a high pressure, a force acts so that the pump housing 1 is lifted upward in the figure due to this pressure. This force does not work when the pressure chamber 11 is at a low pressure. For this reason, the pump housing repeatedly receives a load upward in the drawing.

  As shown in FIG. 9, the flange 41 fixes the pump housing 1 to the engine by two set screws 42. Therefore, when the pump housing 1 is lifted upward as described above, the flange 42 is in a state where the two set screws 42 and the bush 43 are fixed and a bending load is repeatedly applied to the central portion. Due to this repeated load, the flange 41 and the pump housing 1 are deformed, so that there is a problem in that repeated stress is generated and fatigue failure occurs. Furthermore, the sliding portion of the cylinder 6 is also deformed, and the above-described seizure and sticking between the plunger 2 and the cylinder 6 occurs.

  This point will be described with reference to FIG. The flange 41 is manufactured by press molding for productivity reasons. Therefore, the plate thickness t1 of the flange 41 has an upper limit, and in this embodiment, t1 = 4 mm. A welded portion 41 which is a joint portion between the pump housing 1 and the flange 42 is welded and joined by laser welding. In laser welding, it is necessary to irradiate a beam from below in the figure. From the top in the figure, there are other parts and it is impossible to irradiate the laser around the entire circumference. Furthermore, laser welding must penetrate the plate thickness t = 4 mm of the flange 41. If the welding does not penetrate the flange 41, the end face of the welded portion becomes a notch, and stress concentrates on the notched portion due to the above-described repeated load, causing fatigue failure therefrom.

  In order to weld through the flange 41 by laser welding, it is sufficient to increase the output of the laser. However, since heat is always generated for welding, the flange 41 is thermally deformed by the heat. Further, a large amount of spatter generated during welding is generated and fixed to the pump housing 1 and other components. From the above viewpoint, the welding length for through welding by laser welding is better.

  Therefore, in this embodiment, only the thickness t2 of the welded portion 41a is set to t2 = 3 mm. Thereby, the flange 41a can be through-welded by laser welding, and the occurrence of spatter can be minimized. Further, since this t2 = 3 mm portion can be molded by press molding, the productivity is high.

  The plate thickness t2 = 3 mm and the stepped portion of t1 = 4 mm of the welded portion 41a are provided on the engine side. Thereby, the recess 45 is formed. The upper end surface and the lower end surface of the welded part 41a are always raised more than the base material. By providing the recess 45, it is possible to prevent this swell and interference of the engine. When the swell and the engine are in contact, when the high pressure fuel supply pump is fixed to the engine with the set screw 42, bending stress is generated in the flange 41, leading to breakage of the flange 41.

  As a result, the flange 41 can be prevented from being damaged by the repeated load generated along with the high-pressure discharge. Further, it is possible to prevent the flange 41 from being damaged due to the contact of the swell of the welded portion 41a and the engine.

  As described above, when a repeated load is applied to the pump housing 1, the two set screws 42 and the bush 43 are bent and bent in the direction of the repeated load. The welded portion 41 a is welded through the entire circumference by laser welding, and the curvature of the flange 41 spreads to the pump housing 1. On the other hand, the cylinder holder 7 and the pump housing 1 are in contact only with the threaded portions 7g and 1b. The threaded portion 1b and the welded portion 41a of the pump housing 1 are present at a position where they are desired to be separated by a distance m. The minimum wall thickness at the distance m is n. Even if the pump housing 1 is deformed by the bending of the flange 41, the deformation is absorbed by the portion of the distance m and the wall thickness n, and the values of m and n are selected so as not to reach the screw 1b.

  By doing so, deformation of the cylinder 6 due to the curvature of the flange 41 can be prevented. However, all the curvature of the flange 41 must be absorbed by the pump housing 1, and if the repeated stress generated in the pump housing 1 exceeds the allowable value, the pump housing 1 is fatigued and a fuel leakage accident occurs. End up.

In order to prevent such fatigue failure of the pump housing 1, there are the following two methods.
(1) Due to the shape effect of the pump housing 1, the generated stress is made less than the allowable value.
(2) The curvature generated at the flange 41 is reduced.
Hereinafter, these two methods will be described.

  First, (1) will be described. FIG. 11 shows an enlarged view near the welded portion 41a. The maximum stress generated when the pump housing 1 is pulled upward in the figure by repeated load and the flange 41 is bent is the arrow on the surface of the pump housing 1 as shown as the maximum stress in FIG. Occurs in the direction. The generated stress may be dispersed as much as possible by the shape effect so as not to cause stress concentration.

  In this embodiment, as shown in FIG. 11, the R portion 1c and the R portion 1e are connected by the straight portion 1d, and the optimum value is selected. The straight part 1d exists between the two R parts 1c and 1e, and the stress generated on the straight part 1d is evenly distributed. As a result, the maximum value of the generated stress could be reduced without stress concentration.

  Next, (2) will be described. In order to reduce the curvature of the flange 41, there is no method other than increasing the rigidity of the flange 41. However, it is very difficult to set the thickness t of the flange 41 to 4 mm or more from the viewpoint of productivity as described above. Therefore, the diameter of the bush 43 provided only for fixing the set screw 42 is increased. Here, the bending effective distance: O indicates the shortest distance between the end portions of the two bushes 43, and this portion is substantially bent by a repeated load. If the effective bending distance O can be reduced, the rigidity of the flange 41 is improved as a result.

  In this embodiment, the bush 43 is provided with a flange 43a to reduce the bending effective distance: O. As for the height of the bush 43, a height for inserting the fastener 44 is required. When the outer shape of the bush 43 is increased at that height, there are problems such as interference with the pump housing 1 and an increase in the material of the bush 43. By providing the flange portion 43a, these problems can be prevented and the curvature effective distance: O can be reduced.

  As described above, the methods (1) and (2) were achieved, and the stress repeatedly generated in the pump housing 1 could be made to be less than the allowable value of fatigue fracture.

  A second embodiment of the present invention will be described with reference to FIG. The high-pressure fuel supply pump of the present embodiment sucks fuel into the pressurizing chamber 11 through the suction valve (suction valve portion 31a), and discharges the fuel pressurized in the pressurizing chamber 11 through the discharge valve 8b. . A relief passage 88c is formed in the pump housing 1 to connect the passage downstream from the discharge valve 8b and the passage upstream from the discharge valve 8b. The relief valve mechanism 88 includes a check valve 88a that allows the flow of fuel in the relief passage 88c to flow only in one direction from the downstream side of the discharge valve 8b to the upstream side of the discharge valve 8b.

  It should be noted that the upstream side of the discharge valve 8b may be returned to the pressurizing chamber 11 or may be returned to the low pressure fuel chamber 10c. The relief valve mechanism 88 includes a filter 102 mounted on the downstream side of the discharge valve 8b. The filter 102 is formed of a cup-shaped metal plate, and a plurality of holes are punched in the metal plate, or laser. It is formed by processing.

  That is, the filter 102 is attached to the relief valve mechanism 88 to prevent foreign matters flowing in the pump housing 1 and the common rail 23 from flowing into the relief valve seat of the relief valve mechanism 88. In addition, the relief valve mechanism 88 can adjust the valve opening pressure of the relief valve alone, and by attaching the filter 102 after adjusting the valve opening pressure, it is possible to reduce the yield cost when a non-conforming product of pressure adjustment occurs. .

  By press-fitting and fixing the inner cylindrical portion 102c of the filter 102 and the outer cylindrical portion 88b of the relief valve mechanism, the fuel passage 89 can be secured larger than when it is press-fitted by the outer cylindrical portion 102b of the filter 102, and the filter outer surface 102d. The pressure applied to the filter 102 can be reduced by reducing the pressure difference between the filter inner surface 102e and the filter inner surface 102e.

  In addition, the filter 102 is made up of a portion that plays a role as a filter by making a hole in a cylindrical portion having a small outer diameter (filter small diameter portion 102a) by laser processing, and a cylindrical portion having a large outer diameter (filter large diameter portion 102b). The part that plays a role of fixing to the suction joint 101 is configured to be an integral structure. Further, the filter 102 is fixed to the relief valve mechanism 88 by fitting (press-fitting) the inner cylindrical surface portion of the filter large diameter portion 102b of the filter 102 to the outer cylindrical surface portion of the relief valve mechanism.

  The relief valve mechanism 88 has a flat portion perpendicular to the fitting portion (press-fit portion) of the filter 102, and restricts movement of the relief valve mechanism to the side by contacting with the cylindrical stepped flat portion of the filter 102. It is configured as follows. The filter 102 and the fitting part (press-fit part) of the relief valve mechanism are brought into metal contact with each other so as to seal foreign matters mixed in the fuel on the downstream side of the relief valve mechanism 88. The filter 102 has two or more steps on the outer cylindrical portion, and is configured so as to reduce the influence of distortion generated when laser processing a filter hole is transmitted to the fitting portion of the relief valve mechanism.

  The convex portion (filter small-diameter portion 102 a) of the filter 102 is disposed on the upstream side of the relief valve mechanism 88 in the relief passage 88 c where the diameter of the fuel passage is large. The large-diameter portion 102b is press-fitted into the outer cylindrical portion 88b of the relief valve mechanism 88 and fixed. Thereby, the suction resistance of the fuel is reduced, and the stress applied to the filter can be reduced by reducing the pressure difference generated between the outer surface and the inner surface of the filter.

  According to the high-pressure fuel pump described in the above embodiment, when the fuel becomes a high pressure and a high flow rate, or when a block of frozen fuel blocks the flow path of the filter, or when a high-viscosity fuel is used The filter function can be realized even in such environments.

DESCRIPTION OF SYMBOLS 1 ... Pump housing, 10b * 10c ... Low pressure fuel chamber, 11 ... Pressurization chamber, 101 ... Suction joint, 101a ... Small diameter cylindrical part, 101b ... Large diameter cylindrical part, 101c ... Fuel passage, 102 ... Filter, 101a ... Filter small diameter Part, 102b ... large-diameter part of the filter.

Claims (16)

In a high-pressure fuel supply pump comprising a pressurizing chamber for pressurizing fuel, a low-pressure fuel chamber formed on the upstream side of the pressurizing chamber, and a suction joint attached on the upstream side of the low-pressure fuel chamber,
A filter attached to a cylindrical portion on the inner peripheral side of the suction joint;
The filter is a high-pressure fuel supply pump formed of a cup-shaped metal plate, and a plurality of holes formed in the metal plate by punching or laser processing. The high-pressure fuel supply pump according to claim 1,
The filter is a high-pressure fuel supply pump in which a cylindrical portion having a small outer diameter in which the plurality of holes are formed and a cylindrical portion having a large outer diameter that fixes the filter to the suction joint are configured integrally. The high-pressure fuel supply pump according to claim 1 or 2,
A high-pressure fuel supply pump in which the filter is fixed to the suction joint by press-fitting an outer peripheral portion of the cylindrical portion of the filter into an inner peripheral portion of the cylindrical portion of the suction joint. The high-pressure fuel supply pump according to claim 1,
Between the large-diameter cylindrical portion and the small-diameter cylindrical portion of the suction joint, a connection portion that connects these is formed, while the filter has a connection portion that connects the filter large-diameter portion and the filter small-diameter portion. The high pressure fuel supply pump is configured such that the connection portion of the suction joint receives the connection portion of the filter in the axial direction of the suction joint. The high-pressure fuel supply pump according to claim 1,
A high-pressure fuel supply pump that seals foreign matter mixed in low-pressure fuel pumped from a low-pressure fuel pump by bringing a contact portion between the filter and the suction joint into metal contact. The high-pressure fuel supply pump according to claim 1,
The filter is a high-pressure fuel supply pump in which a filter large-diameter portion and a filter small-diameter portion are integrally formed. The high-pressure fuel supply pump according to claim 1,
A high-pressure fuel supply pump in which a convex portion of the filter is attached to the low-pressure fuel chamber side. The high-pressure fuel supply pump according to claim 1,
The filter is a high-pressure fuel supply pump in which a large-diameter portion on the fuel inlet side and a small-diameter portion on the low-pressure fuel chamber side are integrally formed. The high-pressure fuel supply pump according to claim 1,
The suction joint is formed by a hole formed in the pump housing, and the filter is directly attached to the hole of the pump housing. In a high-pressure fuel supply pump that sucks fuel into a pressurizing chamber via a suction valve and discharges fuel pressurized in the pressurization chamber via a discharge valve, from a passage downstream of the discharge valve and the discharge valve A relief passage communicating with the upstream passage,
A relief valve mechanism comprising a check valve that allows the flow of fuel in the relief passage to flow only in one direction from the downstream side of the discharge valve to the upstream side of the discharge valve;
The relief valve mechanism includes a filter attached to the downstream side of the discharge valve,
The filter is a high-pressure fuel supply pump formed of a cup-shaped metal plate, and a plurality of holes formed in the metal plate by punching or laser processing. The high-pressure fuel supply pump according to claim 10,
The filter has an integral structure in which a hole is formed in a cylindrical portion having a small outer diameter by laser processing and serves as a filter, and a portion that serves to fix the filter to the suction joint in a cylindrical portion having a large outer diameter. A high-pressure fuel supply pump configured to be. The high-pressure fuel supply pump according to claim 10 or 11,
A high-pressure fuel supply pump configured to fix the filter to the relief valve mechanism by fitting an inner cylindrical surface portion of the filter to an outer cylindrical surface portion of the relief valve mechanism. The high-pressure fuel supply pump according to any one of claims 10 to 12,
The relief valve mechanism has a flat portion orthogonal to the fitting portion of the filter, and is configured to restrict movement of the relief valve mechanism to the side by contacting with the cylindrical stepped flat portion of the filter. High pressure fuel supply pump. The high-pressure fuel supply pump according to any one of claims 10 to 13,
A high-pressure fuel supply pump configured to seal foreign matter mixed in the fuel on the downstream side of the relief valve mechanism by bringing the fitting portion of the filter and the relief valve mechanism into metal contact. The high-pressure fuel supply pump according to any one of claims 10 to 14,
The filter is provided with a step of two or more steps in the outer cylindrical portion, and a high pressure fuel supply pump configured to reduce the influence of distortion generated when laser processing a filter hole is transmitted to the fitting portion of the relief valve mechanism. . The high-pressure fuel supply pump according to any one of claims 10 to 15,
A high-pressure fuel supply pump in which the convex portion of the filter is disposed in the relief passage where the diameter of the fuel passage is large.

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