JP2007146862A5 - - Google Patents

Description

Fluid pump and high-pressure fuel supply pump

  The present invention relates to a pump that conveys fluid, and is suitable for use in a so-called high-pressure fuel (gasoline) supply pump that pumps high-pressure fuel to a fuel injection valve of a system that supplies fuel (gasoline) directly to a combustion chamber of an internal combustion engine, for example. It is a fluid pump.

  In a conventional apparatus, a hollow cylindrical portion is provided in a pump housing (also referred to as a body or a base) of a pump as a first member, and a cylinder (plunger support member, plunger slide) as a second member is provided in the hollow cylindrical portion. A pressurizing chamber for pressurizing the fuel is formed by closing the cylinder with a seal plate, and a reciprocating plunger whose tip moves in and out of the pressurizing chamber. The second member is supported so as to advance and retreat.

  A conventional apparatus having such a configuration is proposed as a high-pressure fuel supply pump for an internal combustion engine, for example, in JP-A-11-82236.

  In this document, the second member that slidably holds the plunger is made of a wear-resistant metal material, and the first member into which the second member is inserted is a non-wear-resistant metal such as an aluminum alloy having good workability. A high-pressure fuel supply pump is described in which the number of processing steps can be reduced without sacrificing wear resistance and liquid sealability by being made of a material.

Japanese Patent Laid-Open No. 11-82236

  However, in this conventional device, the pressure plate and the low pressure chamber are sealed by pressing a seal plate provided at the open end of the cylinder against the cylinder end surface, and the first member and the second member are almost entirely on the outer periphery of the second member. And are in close contact. For this reason, due to the difference in thermal expansion coefficient between them, when both members are thermally expanded, there is a difference in the amount of thermal deformation between the two members, the cylinder is locally stressed and deformed, and the plunger is engaged with the cylinder. The problem that occurs.

  In addition, since a number of seal rings must be mounted between the first member and the second member, they must be assembled so that they do not come off, so the assembly workability between the first member and the second member is poor and practical. Not right.

  In addition, the member referred to as a plunger in the above prior art includes a member called a piston and a reciprocating rod in another document. In the present invention, a plunger is used as a word meaning the same thing. Of course, functionally, it can be regarded as an element that pressurizes the fluid, and therefore, the expression “pressurizing element” is also used as having a function of compressing the fluid as well as a rod-like form.

Therefore, the technical scope of the “pressurizing element” includes not only the rod-like element described in the embodiment in this specification but also an element having a shape not described in the embodiment having a pressing function .

The object of the present invention is to suppress the occurrence of local stress due to the difference in the amount of thermal expansion by reducing the portion where the pump housing formed of members having different thermal expansion coefficients and the cylinder are in contact as much as possible, and to suppress the deformation of the cylinder. It is in.

In order to achieve the above object, the present invention is configured such that a depression for the pressurizing chamber is formed in the pump housing, and the opening of this recess is sealed with a cylinder to define the pressurizing chamber.

With this configuration, the pump casing and the cylinder do not need to be in contact with each other in the section other than the contact portion on the sealing surface, so that local thermal stress is less generated even if members having different coefficients of thermal expansion are used for both. And deformation of the cylinder can be suppressed.

In another invention of the present invention, since the pump suction valve mechanism and the discharge valve mechanism are mounted on the pump housing, the discharge port hole and the suction port hole can be formed in a pump housing formed of a relatively soft metal material. As a result, the processability has been greatly improved.

In the present invention, there is a wide range of technologies that are not particularly noted, and the fluid conveyance pump is the subject of the technical scope, and the technologies unique to the high-pressure fuel pump are pointed out and described.

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

1 and 2, the configuration and operation of an embodiment of a high-pressure fuel supply pump employing the present invention will be described. This high-pressure fuel supply pump can be regarded as a fluid transfer pump that handles gasoline pressurized to 5 to 20 megapascals as a pressurized fluid. Therefore, it is different from one handling a high pressure fluid of 100 megapascals or more like a high pressure fuel pump of a diesel engine. The conditions are also different from those of, for example, a feed pump that conveys fluid at a pressure slightly higher than atmospheric pressure. Furthermore, it differs from the apparatus which compresses gas like the compressor of a refrigerating cycle.

  FIG. 1 is a vertical sectional view of the entire pump, and FIG. 2 is an exploded perspective view of the pump shown in FIG.

  The pump P includes a pump housing (also referred to as a body or a base) 1 as a first member and a cylinder (also referred to as a plunger support member, a plunger sliding cylinder, or a cylindrical member) 20 as a second member.

The pump housing 1 is softer (hardness is lower; for example, 45 to 70 in HRB) as compared with iron-based materials such as stainless steel and tool steel such as aluminum or aluminum alloy (for example, JIS standard A2017, ADC12, AC4C). Therefore, it is made of a lightweight material that is non-abrasion resistant, has a large thermal expansion coefficient (for example, 23 × 10 ⁻⁶ or more), and is light.

Cylinder 20 is abrasion resistant, such as stainless or tool steel, hard; with (high hardness over 200, for example HRB), thermal expansion coefficient is small (e.g. SUS at 17 × 10 ^-6, iron 10 × 10 ^{- 6} or less), made of heavy alloy.

  The cylinder 20 is assembled to the pump housing 1 so that the annular flat surface 122 formed on the outer periphery of the cylinder 20 abuts on the annular flat surface 122 on the open end side of the bottomed recess 121 of the pump housing 1. As a result, both form a metal contact portion between the aluminum material and the iron-based material at the annular plane.

  A through-hole 201 through which the plunger 2 is inserted is formed at the center of the cylinder 20, and the plunger 2 is slidably supported in the through-hole 201, so that the plunger 2 can advance and retreat in the axial direction.

  Thus, the bottomed recess 121 of the pump housing 1 defines a space 12 in which the plunger 2 advances and retreats with the tip of the cylinder 20. The space 12 functions as a pressurizing chamber for pressurizing the fuel fluid sucked therein by the plunger 2.

  As described above, the cylinder 20 has higher hardness than the pump housing 1.

  The annular flat surface 122 of the pump housing 1 and the annular flat surface 20A of the cylinder 20 are relatively pressed by a pressing mechanism described later. For this reason, the annular flat surface 122 of the pump housing 1 is plastically deformed at a portion where the annular flat surface 20A of the cylinder 20 abuts, and both are strongly pressed against each other, resulting in the formation of a seal portion by metal surface contact.

  Thus, the space 12 in which the plunger 2 advances and retreats is formed as a sealed chamber defined by a later-described suction valve, discharge valve and this seal portion, and as a result, can act as a pressurizing chamber 12 of the fuel pump.

  A fuel suction port 10 and a discharge port 11 are formed in the pump housing 1 made of aluminum alloy. The fuel suction port 10 is connected to the pressurization chamber 12 through a suction chamber 10a and a suction port 10b.

  The discharge port 11 is connected to the pressurizing chamber 12a through the discharge port 11b. A discharge valve unit 6 which will be described in detail later is attached to the discharge port 11.

  The suction chamber 10a and the suction port 10b are formed by cutting or drilling a pump housing 1 made of aluminum alloy.

  A cylindrical processing hole 10A having a larger diameter than the suction port 10b is formed at the inlet of the suction port 10b formed as a small-diameter through hole.

  A cylindrical suction valve unit 5 is mounted in the cylindrical processing hole 10A.

  The suction valve unit 5 has a bottomed cylindrical suction valve holder 5A having a disk-shaped bottom and a cylindrical wall surface around the disk-shaped bottom, and a disk-shaped bottom opposite to the holder 5A assembled therein. And a bottomed cylindrical suction valve 5C having a cylindrical wall surface around it, and a spring 5B made of a coil spring is mounted between the suction valve holder 5A and the bottom of the suction valve 5C facing each other. Yes.

  Further, a plurality of through holes 5D (one of which is visible in FIG. 3) are provided at appropriate intervals in the disk-like bottom of the suction valve holder 5A.

  Since the suction valve holder 5A is made of stainless steel, the pressure contact surface 10B with the pump housing 1 forms a seal portion by metal surface contact like the pressure contact surfaces of the pump housing 1 and the cylinder 20.

  The valve seat member 200A is in contact with the opening end of the suction valve holder 5A so as to close the opening end.

  A through hole 200B connecting the suction chamber 10a and the suction port 10b is formed at the center of the seat member 200A, and the through hole 200B can be closed by a suction valve 5C biased by a spring 5B.

  An annular protrusion 5E is formed on the end face of the suction valve 5C facing the seat member 200A, and the annular protrusion 5E is located concentrically around the central through hole 200B of the seat member 200A. 5E contacts the end surface of the sheet member 200A to close the through hole 200B.

  This sheet member 200 </ b> A is attached to the tip of the electromagnetic plunger mechanism 200.

The electromagnetic plunger mechanism 200 is mounted in a cylindrical recess 200D formed in the pump housing 1 by cutting. A threaded portion 200C is engraved on the inner wall of the cylindrical recess 200D.
The electromagnetic plunger mechanism 200 is assembled in a threaded holder 201 that is screwed into the threaded portion 200C.

  A fixing ring 200E is mounted in an annular groove formed on the outer periphery of the electromagnetic plunger 200, and an outer peripheral corner portion of the ring 200E is engaged with an annular recess formed on the inner periphery of the tip of the holder 201.

  Thus, when the electromagnetic plunger 200 is mounted in the threaded holder 201 and the nut 201A of the threaded holder 201 is rotated, the seal member 200A is sucked through the ring 200E engaged with the annular recess of the holder 201. These parts are mounted on the pump housing 1 by pressing against the valve unit 5 and further pressing the suction valve unit 5 against the pump housing 1.

  At this time, by adjusting the tightening force of the nut 201 </ b> A, the force with which the seat member 200 </ b> A attached to the tip of the electromagnetic plunger mechanism 200 presses the suction valve unit 5 against the pump housing 1 can be adjusted.

  This force contributes to the formation of a seal portion by metal pressure contact between the suction valve unit 5 and the pump housing. For this reason, the holder 5A of the suction valve unit 5 is formed of a member harder than an aluminum alloy such as stainless steel.

  The movable plunger 202 maintains the suction valve 5 in the open position against the force of the spring 5B by the spring 203 when the electromagnetic plunger mechanism 200 is not energized.

  At this time, the movable plunger 202 of the electromagnetic plunger mechanism 200 passes through the through hole 200B of the seat member 200A and extends to the suction valve 5C, and the flat portion of the hemispherical ball 202A provided at the tip of the movable plunger 202 contacts the suction valve 5C. Further, the spring 5B is further compressed to retract the suction valve 5C from the seat member 200A, and the suction chamber 10a and the intake port 10b are communicated with each other through the through hole 5D and the through hole 200B.

  When the electromagnetic plunger mechanism 200 is energized, the movable plunger 202 is attracted against the force of the spring 203. At this time, the intake valve 5C is in a closed position or in relation to the pressure difference between the spring 5B and the fuel upstream and downstream of the intake valve 5C. Controlled to open position.

  The pump housing 1 is integrally formed with a suction port 10 communicating with the suction chamber 10a, and a filter unit 10f is mounted between the suction port 10 and the suction chamber 10a.

  A damper chamber 10e communicating with the suction chamber 10a is formed on the outer periphery of the pressurizing chamber 12 of the pump housing 1.

The damper chamber 10e is sealed with a closing lid 110C that is screwed to the pump housing 1 with a screw 110B across the seal ring 110A, and a damper mechanism 110 that adjusts the pressure in the damper chamber 10e is attached to the closing lid 110C. The damper chamber inside the damper mechanism 110 communicates with the damper chamber 10e on the pump housing 1 side via the closing lid 110C.

  The other end of the discharge port 11 b whose one end communicates with the pressurizing chamber 12 is open to a discharge port 11 formed in the pump housing 1.

  The discharge port 11 is formed in the pump housing 1 as a hole 11D having a diameter larger than that of the discharge port 11b. A screw portion 101C is engraved on the peripheral wall of the hole 11D.

  A discharge port unit 6 is attached to the discharge port 11.

  The discharge valve unit 6 includes a ball valve 11E biased by a spring 11A in a metal nipple 6A.

  The metal nipple 6A has a screw 6B formed on the inner periphery at one end, and a fuel pipe (not shown) is connected to the screw 6B.

  A mounting screw portion 11C that is screwed into a screw portion 101C formed in the pump housing 1 is provided on the outer periphery of the metal nipple 6A.

  A fuel passage having a small diameter passes through the inside of the metal nipple 6A, and a stepped portion is formed around the fuel passage.

  A cylindrical spring receiver 11H with a flange is attached to the fuel passage, and the flange portion is in contact with the stepped portion.

  One end of the spring 11A is received by this flange portion.

  The other end of the spring 11A is held by the outer peripheral step of the valve presser 11B.

  The valve retainer 11B is formed in an elongated solid cylindrical shape, and a plurality of communication grooves 11J are formed in the outer periphery on the outer periphery thereof, and the fuel passes through the communication grooves 11J when the discharge valve 11E is opened. And flows from the discharge port 11b to the discharge opening 11a.

  The discharge valve 11E is always biased in the closing direction by the spring 11A, but when the pressure in the pressurizing chamber 12 exceeds the pressing force of the spring 11A, the discharge valve 11E is opened and pressurized to a high pressure. The fuel is discharged to the discharge port 11 (discharge opening 11a).

  The pressurizing chamber 12 is formed to include a passage extending from the intake port 10b to the intake valve 5 and a passage extending from the discharge port 11b to the discharge valve 11E.

  Between the discharge valve unit 6 and the pump housing 1, a valve seat 11G and a seal ring 11F are arranged concentrically in that order from the inside.

  The valve seat 11G and the seal ring 11F are axially pressed when the discharge valve unit 6 is screwed into the screw portion of the pump housing 1 and the mounting screw portion 11C of the discharge valve unit 6 is screwed into the tip of the discharge valve unit 6 and the pump housing. 1 is sandwiched between.

  The ends of the discharge valve unit 6 on the discharge port 11b side are set so that the inner diameter is smaller than the outer diameter of the valve seat 11G and the outer diameter is larger than the inner diameter of the seal ring 11F.

  As a result, both the valve seat 11G and the seal ring 11F can be pressed against the pump housing by one ring-shaped portion at the tip of the discharge valve unit 6.

  Here, the valve seat 11G is formed of a steel material, and the seal ring 11F is formed of a soft metal material such as an aluminum alloy or a gasket. In the seal structure configured as described above, the first seal by the metal surface contact between the valve seat 11G and the pump housing 1 and the second seal by the seal ring 11F and the pump housing 1 can be formed on the outer periphery thereof, and the seal is ensured.

  Specifically, cavitation when bubbles of high pressure fuel collapse acts between the contact surfaces of the first seal due to metal surface contact between the valve seat 11G and the pump housing 1, and the soft metal pump housing is eroded and the first. Even if the seal is lost, the second seal can prevent leakage to the outside.

  Even in such a state, the cavitation of the pressurized fuel does not reach the second seal because the first seal serves as a protector, so the reliability of the discharge valve portion against breakage is improved.

  Since the destruction of the seal at the discharge valve portion causes the fuel to directly leak into the atmosphere, the improvement of the reliability with respect to the destruction of the seal of the discharge valve portion in this embodiment is an important effect.

  Below, the assembly | attachment aspect of the pump housing 1 and the cylinder 20 is explained in full detail.

  A cylindrical peripheral wall portion 124 having a diameter larger than the diameter of the bottomed recess 121 is provided on the open end side of the bottomed recess 121 (which constitutes a pressurizing chamber of the pump) of the pump housing 1.

  As a result, a step portion is generated between the cylindrical peripheral wall portion 124 and the bottomed recess 121, and an annular flat surface 122 is formed there.

  A thread groove 1B is threaded on the inner peripheral portion of the cylindrical peripheral wall portion 124.

  The plunger 2 is inserted through a through hole 201 provided in the center of the cylinder 20 and is slidably supported.

  As a result, the plunger 2 is supported by the cylinder 20 and allowed to reciprocate, and its tip moves forward and backward in the pressurizing chamber 12.

  The cylinder 20 is formed in a cylindrical shape as a whole, the outer diameter of the pressure chamber side tip is smaller than the diameter of the inner peripheral wall of the bottomed recess of the pump housing 1, and the outer diameter of the intermediate part of the cylinder 20 is the pump housing. It is larger than the inner diameter of one annular plane 122.

  For this reason, a stepped portion is formed on the outer periphery of the cylinder 20 between a tip portion and an intermediate portion located on the pressurizing chamber side, and an annular flat surface 20A is formed there.

  The annular plane 20A can be defined as a plane that intersects the moving direction of the plunger 2, and can be a plane that is not only perpendicular to the central axis of the plunger 1 but also an inclined plane if necessary in practice.

  A similar step is also formed at the opposite end of the cylinder 20, and an annular flat surface 20B is formed there.

  The cylinder 20 is assembled to the pump housing while being accommodated in the cylinder holder 21.

  For this reason, a screw 21B is threaded on the outer periphery of the cylinder holder 21, and an annular plane 21A having a diameter smaller than the outer diameter of the annular plane 20B of the cylinder 20 is formed on the inner periphery.

  When the cylinder 20 is stored in the cylinder holder 21, the annular plane 20 </ b> B and the annular plane 21 </ b> A of the cylinder holder 21 come into contact with each other and are held inside the cylinder holder 21.

  Thus, when the threaded portion 21B of the cylinder holder 21 is screwed into the threaded portion 1B of the pump housing 1, the cylinder 21 is sandwiched between the annular flat surface 122 of the pump housing and the annular flat surface 20B of the cylinder holder 21. Fixed to the housing 1.

  At this time, the relative pressing force between the annular flat surface 122 of the pump housing 1 and the annular flat surface 20A of the cylinder 20 is adjusted by adjusting the screw fastening force with respect to the pump housing 1 so as to form a seal portion. Can be adjusted to.

  In the present embodiment, a contrivance is made for the phenomenon that the difference in the amount of thermal deformation in the axial direction due to the difference in thermal expansion coefficient between the pump housing 1 and the cylinder 20 deteriorates the sealing performance of the pressure contact surfaces of both. Hereinafter, the mechanism will be described in detail with reference to FIG.

  The distance between the pressure contact surface S1 of the pump housing 1 and the cylinder 20 and the pressure contact surface S2 of the pump housing 1 and the cylinder holder 21 is L1. On the other hand, the distance between the pressure contact surface S1 of the pump housing 1 and the cylinder 20 and the intermediate point of the screw coupling portion P1 of the pump housing 1 and the cylinder holder 21 is L2.

  Here, in this embodiment, the screw fastening portion P1 is provided at a position where the two distances L1 and L2 satisfy L1> L2.

  In this embodiment, the pump housing 1 is combined with an aluminum material, and the cylinder 20 is combined with a material having a different linear expansion coefficient such as steel (aluminum material> steel material). The amount of thermal expansion is greater on the pump housing side. Therefore, if the distances L1 and L2 are equal, the difference between the expansion amounts (ΔL1−ΔL2) between the two becomes large, and a gap is formed in the pressure contact surfaces S1 and S2, thereby reducing the sealing performance.

  Therefore, in this embodiment, by setting L1> L2 as described above, the difference between the two expansion amounts (ΔL1−ΔL2) is reduced, thereby suppressing the generation of gaps in the press contact portions S1 and S2 and reducing the sealing performance. It is preventing.

As described above, the pump housing 1 of the present embodiment uses an aluminum alloy (for example, JIS standard A2017, ADC12, AC4C) having a thermal expansion coefficient of about 23 × 10 ⁻⁶ , and the cylinder 20 has a thermal expansion coefficient of 10 × 10 6. ^-6 Tool steel is used.

  Accordingly, the thermal expansion amounts (Δ1, Δ2) when the temperature changes by 100 degrees are calculated as follows.

Δ1 = L1 × 10 × 10 ⁻⁶ × 100 (° C.)
Δ2 = L2 × 23 × 10 ⁻⁶ × 100 (° C.)
Here, if it is preferably set so that L1 = 2 × L2, the amounts of thermal deformation Δ1 and Δ2 of both can be made almost the same, and even if there is a temperature change, no difference in thermal expansion occurs. Since there is no gap in S2, the sealing performance is not impaired.

  Further, a gap G1 is provided between the outer peripheral surface of the pressure chamber side tip of the cylinder 20 and the inner peripheral surface of the pump housing 1, and gaps G2 and G5 are provided between the inner diameter side of the cylinder holder 21 and the outer periphery of the cylinder 20. Gap G3, G4 is provided between 1 inner peripheral surface and the outer periphery of the cylinder holder 21, and it is comprised so that the pump housing 1 and the cylinder 20 may not contact directly in radial direction.

  The cylinder holder 21 and the cylinder 20 have a circumferential surface fitting portion Q1 for radial positioning, and the positions of the circumferential surface fitting portion Q1, the cylinder holder 20, and the screw coupling portion P1 of the pump housing 1 are the cylinder axis. It is shifted so that it does not overlap in the direction along. In other words, the gap G3 is provided on the outer peripheral portion of the peripheral surface fitting portion Q1, and the gap G2 is provided on the inner side of the screw coupling portion P1. The portion is deformed inward within the range of the gap G2, and the peripheral surface fitting portion Q1 is not affected by the deformation of the cylinder holder 21.

  Thus, in this embodiment, the screw fastening portion P1 is provided on the opening end side of the cylinder holder 21 with respect to the circumferential surface fitting portion Q1, and the wall thickness at the screw fastening portion P1 of the cylinder holder 21 is the circumferential surface fitting. Since it is thinner than the thickness in the part P1, it is devised so that the deformation due to the thermal expansion of the pump casing 1 is absorbed by the deformation of the screw fastening part P1, and the influence on the peripheral surface fitting part Q1 is suppressed. . In addition, a slight gap is provided in the peripheral surface fitting portion Q1 within a range that does not interfere with the positioning of the cylinder 20 in the radial direction, and this configuration ensures the coaxiality of the cylinder holder 21 and the cylinder 20, This is effective in suppressing the tightening force acting on the cylinder 20 when the screw fastening portion P1 is deformed in the inner diameter direction due to the thermal expansion of the pump housing 1.

  Thus, according to the above configuration, the gap between the sliding portion of the cylinder 20 and the plunger 2 can be properly maintained, and seizure and biting of the plunger 2 can be prevented.

  Further, since the cylinder holder 21 is made of a material having a lower thermal conductivity than that of the pump housing 1 (a stainless steel is used in this embodiment), the heat of the pump housing 1 is difficult to be transmitted to the cylinder 20. There is an effect to suppress the seizure of the.

  Further, a resin coating is applied to the threaded portion of the cylinder holder 21, and this configuration can further reduce heat transfer from the pump housing 1.

  An annular low-pressure chamber 10c that communicates with the suction chamber 10a via a passage 10d is provided on the outer periphery of the cylinder 20.

  Thereby, while reducing the heat transfer from the pump housing 1 to the cylinder 20, the cylinder 20 can be cooled with fuel.

  Also, inside the cylinder holder 21, a plunger seal 30 is sealed that seals fuel outflow from the sliding portion of the plunger 2 to the cam 100 side and seals oil intrusion from the cam side to the plunger sliding portion. ing.

  Thereby, since the cylinder 20 and the plunger seal 30 are engaged with the cylinder holder 21 which is the same member, the plunger seal 30 and the plunger 2 which is the sliding material can be held coaxially, and the plunger sliding portion is sealed. The property can be kept good.

  A plunger seal chamber 30a formed on the cylinder opening end side (inner side of the pump) of the plunger seal 30 passes through a sliding portion clearance X between the cylinder 20 and the plunger 2, and enters a fuel reservoir 20a provided in the cylinder 20. It is connected to the annular chamber 10c through the passage 20b, the recess 10f, and the passage 20D.

  The cylinder 20 is divided into a depression 10f, a passage 20D, a low-pressure chamber connected to the suction chamber 10a composed of the annular chamber 10c, and a plunger seal chamber 30a in which atmospheric pressure acts.

  The plunger seal chamber 30 a passes through a communication hole 21 a provided in the cylinder holder 21, an annular chamber 10 g formed on the outer periphery of the positioning portion Q <b> 1 of the cylinder holder 21, and a passage 121 a provided in the pump housing 1. Connected to.

  The return pipe 40 is connected to a fuel tank 50 having a substantially atmospheric pressure through a return pipe (not shown). Accordingly, since the plunger seal chamber 30a communicates with the fuel tank 50 through the return pipe 40, the plunger seal chamber 30a has an atmospheric pressure substantially equal to the fuel tank pressure.

  With the above configuration, fuel leaking from the sliding clearance X between the cylinder 20 and the plunger 2 from the pressurizing chamber 12 flows from the fuel reservoir 20a through the passages 20b and 20D toward the suction chamber 10a.

  On the other hand, since the pressure of the low-pressure fuel is applied from the suction chamber 10a to the fuel reservoir 20a, the pressure is higher than the plunger seal chamber 30a at atmospheric pressure through the sliding clearance X. Accordingly, fuel flows from the fuel reservoir 20a to the plunger seal chamber 30a at atmospheric pressure. This fuel flows to the fuel tank 50 through the return pipe 40. However, at a high temperature, the plunger seal chamber 30a is almost at atmospheric pressure, so the fuel is easily gasified.

  In this embodiment, the distance LX of the sliding clearance X from the fuel reservoir 20a to the opening on the plunger seal 30 side of the cylinder 20 is shorter than the reciprocating sliding length of the plunger.

  Thereby, when the plunger 2 is located at the top dead center, the fuel adhering to the plunger 2 in the fuel reservoir 20a passes through the cylinder opening 20d when the plunger 2 is located at the bottom dead center. A fuel oil film can be secured in this case, lubricity can be improved, and wear of the cylinder 20 and the plunger 2 can be reduced.

  Further, a throttle portion 21 b is provided between the plunger seal chamber 30 a and the return pipe 40.

  Thus, by regulating the amount of fuel flowing from the plunger seal chamber 30a to the fuel tank 50, the fuel tends to stay in the plunger seal chamber 30a, and the wear resistance of the plunger seal 30 and the cylinder opening 20d is improved by fuel lubrication. Can measure. In particular, it is effective when the plunger seal 30 is above the return pipe 40 when the pump is mounted (the top and bottom are reversed with respect to the illustrated direction).

  The lifter 3 provided at the lower end of the plunger 2 is pressed against the cam 100 by a spring 4. When the cam 100 is rotated by an engine camshaft or the like, the lifter 3 is pushed up against the spring 4 and pushed down by the spring 4. Thus, the plunger 2 is supported by the cylinder 20 and reciprocally slides in the through hole 201. Then, the volume in the pressurizing chamber 12 is changed.

  A plunger seal 30 is provided at the lower end of the cylinder 20 in the drawing to prevent fuel from flowing out to the cam 100 side.

  A suction chamber 10a that is a low-pressure fuel chamber, an annular low-pressure chamber 10c that surrounds the seal portion, and a damper chamber that is outside the upper wall surface of the pressurization chamber 12 are disposed on the outer periphery of the pressurization chamber 12 via a suction valve holder 5A. 10e is provided.

  In the embodiment configured as described above, even if fuel leaks from the seal portion due to the metal pressure contact between the cylinder and the metal contact portion of the pump housing, the fuel does not leak outside the pump.

  Since the cylinder 20 is made of a material harder than the pump housing 1, the cylinder 1 bites into the cylinder 1 side pressure contact surface, and the sealing performance can be improved.

  In particular, when a soft material such as aluminum is used for the cylinder 1, the sealing performance can be improved.

  In addition, a low pressure chamber 10f communicating with the suction chamber 10a is provided in the upper portion of the pump chamber 12a in the drawing, and the wall 1a therebetween is located in the entire wall of the pressurization chamber 12. The weakest part.

  As a result, when the pressure in the pressurizing chamber rises abnormally due to some failure, the weakest part is first damaged and the high pressure fuel is discharged into the damper chamber 10e. When this happens, fuel leakage can be prevented.

  In this embodiment, the solenoid 200 for controlling the opening / closing timing of the suction valve 5 is held in the suction chamber 10 a by the solenoid holder 210, and is annular around the solenoid coil between the solenoid 200 and the solenoid holder 210. The fuel chamber is formed.

  Thereby, the solenoid 200 can be cooled with the fuel. In addition, you may form an annular fuel chamber in a solenoid outer peripheral part, without using a solenoid holder.

  Further, by providing a screw portion on the outer peripheral portion of the solenoid holder 210 and engaging with the pump housing, heat transfer from the pump housing 1 to the solenoid 200 can be reduced.

  Furthermore, by using a material having a lower thermal conductivity than the pump housing 1 for the solenoid holder 210, heat of the pump housing 1 becomes difficult to be transmitted to the solenoid 200, and the burnout of the solenoid 200 can be prevented.

  Furthermore, the heat transfer from the pump housing 1 can be reduced by coating the screw portion of the solenoid holder 210 with a resin.

  Further, by gradually reducing the drive current of the solenoid 200 when it is OFF, it is possible to reduce the collision force at the time of OFF and to prevent wear and breakage of the collision part.

  Furthermore, the operating distance of the drive part of the solenoid 200 is made smaller than the operating distance of the intake valve 5.

  Thereby, even when the operation time of the solenoid 200 (responsiveness at the time of OFF) is slow, the suction valve 5 is quickly opened when the pressure in the pressurizing chamber changes (when shifting from the discharge process to the suction process), A sufficient opening area of the intake valve 5 can be secured, and the operating distance of the solenoid 200 can be reduced to reduce the collision force.

  As a result, the passage resistance at the suction valve 5 is reduced, so that a pressure drop in the pressurized chamber during the suction process can be prevented, and the occurrence of cavitation can be suppressed.

  By making the operating distance of the discharge valve 6 shorter than that of the suction valve 5, the backflow of the high-pressure fuel into the pressurizing chamber due to the delay in closing the discharge valve 6 (when shifting from the discharge process to the suction process) is minimized. And the occurrence of cavitation in the pressurized chamber can be suppressed.

  1C is a seal ring that seals between the engine body, and 21C is a seal ring that seals between the pump housing 1 and the cylinder holder 21.

  The outer periphery of the cylinder 20 is sealed by a seal ring 21 </ b> C and a plunger seal 30, and is formed as a low pressure chamber connected to the intake passage 10 a or the tank 50. Therefore, even if fuel leaks from the pressure contact portion between the pump housing 1 and the cylinder 20, the fuel does not leak directly into the atmosphere.

  According to the present invention, even when a soft material such as aluminum is used for the pump housing, it is possible to provide a pump that is highly reliable and that is reduced in cost and weight by improving machinability.

  The basic structural points of the present embodiment will be described with reference to FIG.

  The first feature of the present embodiment is that a recess (bottomed) serving as a pressurizing chamber is formed in the pump housing, and the recess is defined as a pressurizing chamber by mounting a cylinder on the pump housing.

  According to this configuration, the cylinder and the pump housing need only be in pressure contact with each other only at the seal portion, and both do not need to contact each other particularly in the circumferential direction. This has the effect of reducing the deformation of the cylinder due to the difference in thermal expansion when the pump housing and the cylinder are made of different materials.

  The second feature of the present embodiment is that a recess (bottomed) that becomes a pressurizing chamber and a low pressure chamber is formed in the pump housing, and the recess is formed by mounting a cylinder in the recess of the pump housing. The pressure chamber and the low pressure chamber are separately defined, a seal mechanism is provided between the opening of the recess of the pump housing and the plunger, and the low pressure chamber is connected to a suction passage or a fuel tank. While maintaining the effect of the above feature, the outside of the high pressure chamber is surrounded by the low pressure chamber to reduce the possibility of high pressure fuel leaking directly into the atmosphere.

The following is a summary of the embodiments of the present embodiment.

[Embodiment 1]
Pump housing,
A cylinder combined with the pump housing,
A plunger that is supported by the cylinder so as to be reciprocally movable and pressurizes a fluid in a pressurizing chamber formed between the cylinder and the pump housing;
A metal seal portion formed by press-contacting the pump housing and the cylinder with a surface intersecting the moving direction of the plunger;
A pressing mechanism that presses the pump housing and the cylinder relatively toward the metal seal portion.
With fluid pump.

[Embodiment 2]
Pump housing,
A cylinder combined with the pump housing,
A plunger that is supported by the cylinder so as to be reciprocally movable and pressurizes a fluid in a pressurizing chamber formed between the cylinder and the pump housing;
The pump housing and the cylinder form a seal portion on the surface intersecting the moving direction of the plunger, and the pump housing and the cylinder are relatively pressed so that they are in a non-contact state except for the seal portion. Pressing mechanism
With fluid pump.

[Embodiment 3]
Pump housing,
A cylinder combined with the pump housing,
A plunger for pressurizing fluid in a pressurizing chamber formed between the cylinder and the pump housing;
In what has
A fluid pump in which a gap is provided between radially facing surfaces of the pump housing and the cylinder.

[Embodiment 4]
Forming a recess in the pump housing,
A cylinder member is assembled to the opening of the recess to define the recess as a pressure chamber,
A suction valve mechanism for supplying fluid to the pressurizing chamber and a discharge valve mechanism for taking out the pressurized fluid from the pressurizing chamber;
A fluid pump configured to pressurize a fluid in the pressurizing chamber by a reciprocating plunger supported by the cylinder.

[Embodiment 5]
Forming a recess in the pump housing,
A cylinder member is assembled to the opening of the recess to define the recess as a pressure chamber,
A suction valve mechanism for supplying fluid to the pressurizing chamber and a discharge valve mechanism for taking out the pressurized fluid from the pressurizing chamber;
A fluid reciprocating plunger supported by the cylinder is configured to pressurize the fluid in the pressurizing chamber;
The fluid pump which mounts the said cylinder in the said pump housing by fastening the holder member which accommodates the said cylinder to the thread part of the said pump housing.

[Embodiment 6]
Metal pump housing with recesses,
A thread groove formed in the inner wall of the metal pump housing on the open end side of the recess;
A holder member formed on the outer periphery of a screw portion to be screwed into the screw groove;
A metal cylinder held by the holder member and assembled with the metal pump housing to define the recess as a fluid pressurizing chamber;
Plunger that is supported by the metal cylinder so as to be reciprocally movable, and advances and retreats in the pressurizing chamber.
With fluid pump.

[Embodiment 7]
A pump housing made of an aluminum alloy having a recess and having a thread groove formed in the peripheral wall on the open end side of the recess;
A holder member screwed into the thread groove,
An iron-based metal cylinder housed in the holder member;
The metal pump housing and the cylinder are in pressure contact with each other in a plane crossing the advance / retreat direction of the plunger by screwing the holder member to the metal pump housing to define the recess as a pressurizing chamber. ,
A plunger that is supported by the cylinder so as to be reciprocally movable, and advances and retreats into the pressurizing chamber to pressurize the fluid;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurizing chamber
With fluid pump.

[Embodiment 8]
In the seventh embodiment, the holder and the cylinder include a pressure contact surface that receives a fastening force when the holder is screw-fastened to a screw portion of the pump cylinder,
The cylinder is sandwiched and fixed between the pressure contact surface and the high pressure seal surface,
A screw fastening portion between the holder and the pump cylinder is formed in a range between the pressure contact surface and the high pressure seal surface,
A fluid pump in which a gap is formed between the holder inside the screw fastening portion and the cylinder.

[Embodiment 9]
9. The fluid pump according to Embodiment 8, wherein a radial positioning portion between the holder and the cylinder is formed between a pressure contact surface position between the holder and the cylinder and a screw fastening portion position.

[Embodiment 10]
The fluid pump according to Embodiment 9, wherein a radial thickness of the holder at the position of the positioning portion is thicker than a radial thickness of the holder at the screw fastening portion.

[Embodiment 11]
The fluid pump in which the gap is formed between the outer periphery of the holder of the site | part in which the said positioning part was formed in the thing of Embodiment 9 and 10, and the said pump cylinder.

[Embodiment 12]
A pump housing made of an aluminum alloy having a recess and having a thread groove formed in the peripheral wall on the open end side of the recess;
A holder member screwed into the thread groove,
An iron-based metal cylinder housed in the holder member;
A high pressure seal part formed between the metal pump housing and the cylinder by screwing the holder member to the metal pump housing, and defining the recess of the pump housing as a pressurizing chamber;
A plunger that is supported by the cylinder so as to be reciprocally movable, and advances and retreats into the pressurizing chamber to pressurize the fluid;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurized chamber;
A fluid sealing mechanism mounted between the plunger and the inner wall of the holder;
A sealing element mounted between the outer periphery of the holder and the pump housing;
A fluid pump in which an outer periphery of the cylinder is connected to a low-pressure fluid passage.

[Embodiment 13]
Pump housing made of aluminum alloy with a recess,
An iron-based metal cylinder mounted in a recess of the pump housing and defining the recess into a pressure chamber and a low pressure chamber;
A plunger that is supported by the iron-based metal cylinder so as to be able to reciprocate and pressurizes the fluid by moving back and forth in the pressurizing chamber;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurized chamber;
A fluid seal mechanism mounted between the plunger and the pump housing on the open end side of the pump housing;
A fluid pump in which an outer periphery of the cylinder is connected to a low-pressure fluid passage.

[Embodiment 14]
Pump housing made of aluminum alloy with a recess,
An iron-based metal cylinder mounted on the pump housing and defining the recess as a pressurizing chamber in cooperation with the pump housing;
A plunger that is supported by the iron-based metal cylinder so as to be able to reciprocate and pressurizes the fluid by moving back and forth in the pressurizing chamber;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurized chamber;
With fluid pump.

[Embodiment 15]
A first member with a recess,
A second member assembled to the first member and defining the recess as a fluid pressurizing chamber;
A plunger that is reciprocally supported by the second member and pressurizes the fluid in the pressurizing chamber;
The first member and the second member are in pressure contact with each other at a plane intersecting the reciprocating direction of the plunger.
And a seal part formed by
A fluid pump including a pressing mechanism that relatively presses the first member and the second member toward a surface that intersects a reciprocating direction of the plunger.

[Embodiment 16]
Metal pump housing with recesses,
A metal cylinder made of a metal material, which is assembled to the metal pump housing and defines the recess as a fluid pressurizing chamber, the hardness of which is higher than that of the metal pump housing;
A plunger supported by the metal cylinder so as to be capable of reciprocating in the axial direction;
A seal portion formed by press-contacting the metal pump housing and the metal cylinder at a surface intersecting the reciprocating direction of the plunger;
A fluid pump including a pressing mechanism that presses the metal pump housing and the metal cylinder relatively toward the seal portion.

[Embodiment 17]
The fluid pump according to Embodiments 15 and 16, wherein the first member and the metal pump housing are made of an aluminum alloy,
A fluid pump in which the second member and the metal cylinder are made of an iron-based alloy whose hardness is higher than that of an aluminum alloy.

[Embodiment 18]
In the fluid pump according to Embodiments 15 and 16, between the inner periphery of the first member and the outer periphery of the second member, and between the inner periphery of the metal pump housing and the outer periphery of the metal cylinder, The fluid pump in which the clearance gap which accept | permits the thermal deformation difference between both by the 1st member, the 2nd member, and the thermal expansion difference of the said metal pump housing and a metal cylinder is formed.

[Embodiment 19]
Metal pump housing with recesses,
A thread groove formed in the inner wall of the metal pump housing on the open end side of the recess;
A holder member formed on the outer periphery of a screw portion to be screwed into the screw groove;
A metal cylinder that is held by the holder member and is mounted on the metal pump housing to define the recess as a fluid pressurizing chamber;
It is supported by the metal cylinder so as to be able to reciprocate, and includes a plunger that moves forward and backward in the pressurizing chamber,
A fluid pump in which a high-pressure seal portion is formed by press-contacting the metal pump housing and the metal cylinder at a surface intersecting a reciprocating direction of the plunger by screwing the screw member into the metal pump housing.

[Embodiment 20]
Plunger,
A wear-resistant metal plunger sliding cylinder that supports the plunger so as to be reciprocally slidable,
A non-abrasion resistant metal base on which the plunger sliding cylinder is separably assembled;
A seal portion formed by press-contacting the base and the plunger sliding cylinder on a surface intersecting the reciprocating direction of the plunger;
A fluid pump comprising a pressing mechanism that presses the base and the plunger sliding cylinder relatively toward the seal portion.

[Embodiment 21]
A plunger that reciprocates in the pressure chamber to pressurize the fluid;
A cylindrical member made of wear-resistant metal mainly composed of iron that slidably supports the plunger,
A non-abrasion resistant metal pump body that is assembled with the tubular member to form a fluid pressurizing chamber;
A seal portion formed by press-contacting the pump body and the cylindrical member at a surface intersecting the advancing / retreating direction of the plunger;
A fluid pump including a pressing mechanism that presses the pump body and the tubular member relatively toward the pressure contact surface.

[Embodiment 22]
The fluid pump according to Embodiments 20 and 21, wherein the base and the pump body are formed of an aluminum alloy, and the plunger sliding cylinder and the cylindrical member are formed of an iron-based alloy harder than the aluminum alloy.

[Embodiment 23]
Pump housing,
A cylinder combined with the pump housing,
Sealing a pressurizing chamber formed between the cylinder and the pump housing with a sealing portion formed at a pressure contact portion between the pump housing and the cylinder;
A pressing mechanism that presses the pump housing and the cylinder relatively toward the sealing portion.
With fluid pump.

[Embodiment 24]
Pump housing,
A cylinder combined with the pump housing,
A pressurizing element for pressurizing a fluid in a pressurizing chamber or a fluid formed between the cylinder and the pump housing;
A sealing part formed by pressure-contacting the pump housing and the cylinder on a surface intersecting the moving direction of the pressurizing element;
A pressing mechanism that presses the pump housing and the cylinder relatively toward the sealing portion.
With fluid pump.

[Embodiment 25]
Pump housing,
A cylinder combined with the pump housing,
A pressurizing element for pressurizing a fluid in a pressurizing chamber or a fluid formed between the cylinder and the pump housing;
A metal seal portion formed by press-contacting the pump housing and the cylinder with a surface intersecting the moving direction of the pressurizing element;
A pressing mechanism that presses the pump housing and the cylinder relatively toward the metal seal portion.
With fluid pump.

[Embodiment 26]
Pump housing,
A cylinder combined with the pump housing,
A pressurizing element configured to pressurize a fluid or a fluid in a pressurizing chamber formed between the cylinder and the pump housing;
The pump housing and the cylinder form a seal portion on a surface that intersects the moving direction of the pressurizing element, and the pump housing and the cylinder are relatively positioned so as to be in a non-contact state except for the seal portion. Press mechanism to press
With fluid pump.

[Embodiment 27]
A pump housing having a recess,
A cylinder assembled in the recess of the pump housing,
In what has
The fluid pump which provided the space | gap between the opposing surfaces of the radial direction of the recessed inner wall surface of the said pump housing, and the said cylinder.

[Embodiment 28]
Forming a recess in the pump housing,
A cylinder member is assembled to the opening of the recess to define the recess as a pressure chamber,
A suction valve mechanism for supplying fluid or fluid to the pressurizing chamber and a discharge valve mechanism for taking out the pressurized fluid from the pressurizing chamber are provided in the pump housing,
A fluid pump configured to pressurize a fluid in the pressurizing chamber with a pressurizing element.

[Embodiment 29]
Forming a recess in the pump housing,
A cylinder member is assembled to the opening of the recess to define the recess as a pressure chamber,
A suction valve mechanism for supplying fluid to the pressurizing chamber and a discharge valve mechanism for taking out the pressurized fluid from the pressurizing chamber;
Configured to pressurize the fluid in the pressurizing chamber by a pressurizing element;
The fluid pump which mounts the said cylinder in the said pump housing by fastening the holder member which accommodates the said cylinder to the thread part of the said pump housing.

[Embodiment 30]
Metal pump housing with recesses,
A thread groove formed in the inner wall of the metal pump housing on the open end side of the recess;
A holder member formed on the outer periphery of a screw portion to be screwed into the screw groove;
A metal cylinder held by the holder member and assembled with the metal pump housing to define the recess as a fluid pressurizing chamber;
With fluid pump.

[Embodiment 31]
A pump housing made of an aluminum alloy having a recess and having a thread groove formed in the peripheral wall on the open end side of the recess;
A holder member screwed into the thread groove,
An iron-based metal cylinder housed in the holder member;
A sealing portion that is a pressure contact portion between the metal pump housing and the cylinder by screwing the holder member to the metal pump housing, and defines the recess as a pressurizing chamber;
A pressurizing element for advancing and retracting into the pressurizing chamber to pressurize the fluid;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurizing chamber
With fluid pump.

[Embodiment 32]
In the embodiment 31, the holder and the cylinder include a pressure contact surface that receives a fastening force when the holder is screw-fastened to a screw portion of the pump cylinder,
The cylinder is sandwiched and fixed between the pressure contact surface and the sealing portion,
A screw fastening portion between the holder and the pump cylinder is formed in a range between the pressure contact surface and the sealing portion,
A fluid pump in which a gap is formed between the holder inside the screw fastening portion and the cylinder.

[Embodiment 33]
33. The fluid pump according to embodiment 32, wherein a radial positioning portion between the holder and the cylinder is formed between a pressure contact surface position between the holder and the cylinder and a screw fastening portion position.

[Embodiment 34]
33. The fluid pump according to embodiment 32, wherein a radial thickness of the holder at the position of the positioning portion is thicker than a radial thickness of the holder at the screw fastening portion.

[Embodiment 35]
  34. The fluid pump according to Embodiments 32 and 33, wherein a gap is formed between an outer periphery of the holder at a portion where the positioning portion is formed and the pump housing.

[Embodiment 36]
A pump housing made of an aluminum alloy having a recess and having a thread groove formed in the peripheral wall on the open end side of the recess;
A holder member screwed into the thread groove,
An iron-based metal cylinder housed in the holder member;
The holder member is formed between the metal pump housing and the cylinder by screwing the holder member to the metal pump housing, and pressurizes the recess of the pump housing.
A sealing part defining a chamber,
A pressurizing element for pressurizing a fluid in the pressurizing chamber;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurized chamber;
A fluid seal mechanism mounted between the pressurizing element and the holder inner wall;
A fluid sealing element mounted between the outer periphery of the holder and the pump housing;
A fluid pump in which an outer periphery of the cylinder is connected to a low-pressure fluid passage.

[Embodiment 37]
Pump housing made of aluminum alloy with a recess,
An iron-based metal cylinder mounted in a recess of the pump housing and defining the recess into a pressure chamber and a low pressure chamber;
A pressurizing element for pressurizing a fluid in the pressurizing chamber;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurized chamber;
A fluid seal mechanism mounted between the pressurizing element and the pump housing on the open end side of the pump housing;
A fluid pump in which an outer periphery of the cylinder is connected to a low-pressure fluid passage.

[Embodiment 38]
Pump housing made of aluminum alloy with a recess,
An iron-based metal cylinder mounted on the pump housing and defining the recess as a pressurizing chamber in cooperation with the pump housing;
A pressurizing element for pressurizing the fluid in the pressurizing chamber;
A suction valve mechanism mounted on the pump housing and supplying fluid to the pressurizing chamber;
A discharge valve mechanism mounted on the pump housing and taking out pressurized fluid from the pressurized chamber;
With fluid pump.

[Embodiment 39]
A first member with a recess,
A second member assembled to the first member and defining the recess as a fluid pressurizing chamber;
A pressurizing element for pressurizing the fluid in the pressurizing chamber;
A seal portion formed by press-contacting the first member and the second member;
A fluid pump including a pressing mechanism that presses the first member and the second member relatively toward the seal portion.

[Embodiment 40]
Metal pump housing with recesses,
A metal cylinder made of a metal material, which is assembled to the metal pump housing and defines the recess as a fluid pressurizing chamber, the hardness of which is higher than that of the metal pump housing;
A pressure element supported by the metal cylinder so as to be reciprocally movable in the axial direction;
A seal portion formed by press-contacting the metal pump housing and the metal cylinder at a surface intersecting the reciprocating direction of the pressurizing element;
A fluid pump including a pressing mechanism that presses the metal pump housing and the metal cylinder relatively toward the seal portion.

[Embodiment 41]
The fluid pump according to embodiment 39, 40, wherein the first member and the metal pump housing are made of an aluminum alloy,
A fluid pump in which the second member and the metal cylinder are made of an iron-based alloy whose hardness is higher than that of an aluminum alloy.

[Embodiment 42]
In the fluid pump according to Embodiments 39 and 40, between the inner periphery of the first member and the outer periphery of the second member, and between the inner periphery of the metal pump housing and the outer periphery of the metal cylinder, The fluid pump in which the clearance gap which accept | permits the thermal deformation difference between both by the 1st member, the 2nd member, and the thermal expansion difference of the said metal pump housing and a metal cylinder is formed.

[Embodiment 43]
Metal pump housing with recesses,
A thread groove formed in the inner wall of the metal pump housing on the open end side of the recess;
A holder member formed on the outer periphery of a screw portion to be screwed into the screw groove;
A metal cylinder that is held by the holder member and is mounted on the metal pump housing to define the recess as a fluid pressurizing chamber;
A pressurizing element that pressurizes the fluid in the pressurizing chamber;
A fluid pump that forms a fluid seal portion by press-contacting the metal pump housing and the metal cylinder body by screwing the screw member into the metal pump housing.

[Embodiment 44]
Plunger,
A wear-resistant metal plunger sliding cylinder that supports the pressurizing element so as to be reciprocally slidable,
A non-abrasion resistant metal base on which the plunger sliding cylinder is separably assembled;
A seal portion formed by press-contacting the base and the plunger sliding cylinder;
A fluid pump comprising a pressing mechanism that presses the base and the plunger sliding cylinder relatively toward the seal portion.

[Embodiment 45]
A pressurizing element that reciprocates in the pressurizing chamber to pressurize the fluid;
A cylindrical member made of wear-resistant metal mainly composed of iron that slidably supports the pressure element,
A non-abrasion resistant metal pump body that is assembled with the tubular member to form a fluid pressurizing chamber;
A seal portion formed by press-contacting the pump body and the tubular member on a surface intersecting the advancing and retreating direction of the pressurizing element;
A fluid pump including a pressing mechanism that presses the pump body and the tubular member relatively toward the seal portion.

[Embodiment 46]
46. The fluid pump according to any of Embodiments 44 and 45, wherein the base and the pump body are formed of an aluminum alloy, and the plunger sliding cylinder and the cylindrical member are formed of an iron-based alloy harder than the aluminum alloy.

[Embodiment 47]
Embodiments 41 to 46 wherein the fluid pump pressurizes the fluid to 5 to 20 megapascals.

[Embodiment 48]
Embodiments 41 to 46 are fluid pumps, wherein the fluid pump pressurizes gasoline to 5 to 20 megapascals.

The aim of the above embodiment is summarized as follows.

A pressing mechanism is provided so that the first member and the second member are pressed against each other at a plane crossing the advancing / retreating direction of the plunger (preferably a plane perpendicular to the advancing / retreating direction). Alternatively, a metal seal part with another metal member as an intermediate is formed, and the pressurizing chamber formed between the first member and the second member is sealed with this metal seal part.

As a result, a good sealing performance can be obtained without providing a seal ring or a gasket between the first member and the second member, and as a result, the assembling work has been greatly simplified.

In addition, with this configuration, the opposing surfaces (particularly the peripheral surface) of both members other than the pressure contact surface as the seal portion are not required to have close contact, so that a sufficient gap can be provided, and both members have a thermal expansion coefficient. Even when formed by different members, stress due to local thermal expansion differences is less likely to occur.

In addition, the embodiment proposes a mechanism for storing the second member in a threaded holder and screwing the first member to the first member as a mechanism for easily assembling the second member to the first member.

Specifically, it is advantageous if this mechanism constitutes a pressing mechanism.

According to the above embodiment, the objects of the following examples can be achieved.
1) This kind of seals between the first member and the second member are few while maintaining the advantage of the above-mentioned prior art that the number of processing steps can be reduced without impairing the wear resistance and liquid sealability. A high-pressure fuel supply pump is provided.
2) Provided is a high-pressure fuel supply pump of this type that is excellent in assembling ability regardless of the material of the first member and the second member.
3) This type of apparatus is provided that does not require a discharge hole for discharging a high-pressure fluid in a hard metal cylinder.

  In the present invention, there is a wide range of technologies that are not particularly noted, and the fluid conveyance pump is the subject of the technical scope, and the technologies unique to the high-pressure fuel pump are pointed out and described.

The present invention relates to a pump that conveys fluid, and is suitable for use in a so-called high-pressure fuel (gasoline) supply pump that pumps high-pressure fuel to a fuel injection valve of a system that supplies fuel (gasoline) directly to a combustion chamber of an internal combustion engine, for example. It is a fluid pump.

1 is a vertical sectional view of a high-pressure fuel supply pump according to an embodiment of the present invention. It is a disassembled perspective view of the high pressure fuel supply pump of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is drawing for demonstrating the characteristic of a present Example. It is a vertical sectional view of a high pressure fuel supply pump according to another embodiment of the present invention.

Explanation of symbols

1 Pump housing 2 Plunger 5 Suction valve unit 6 Discharge port unit 10a Suction chamber 10c Annular passage 10d Passage 12 Space (Pressure chamber)
20 Cylinder 30 Plunger seal 30a Fuel reservoir 121 Bottomed recess

Claims (6)

Pump housing,
A cylinder combined with the pump housing,
Plunger that slides on the cylinder and pressurizes the fluid in the pressurizing chamber formed between the cylinder and the pump housing.
In what has
A gap is provided between radially facing surfaces of the pump housing and the cylinder,
Provided in the contact portion between the pump housing and the cylinder formed radially outside the gap is a metal contact seal portion between the pump housing and the cylinder outer peripheral portion,
The pressurizing chamber is defined by the metal contact seal portion and the sliding surface between the plunger and the cylinder.
Fluid pump. In claim 1,
A suction valve mechanism for supplying fluid to the pressurizing chamber; and a discharge valve mechanism for taking out the pressurized fluid from the pressurizing chamber.
The metal contact seal portion is formed at a position away from the tip of the cylinder in the axial direction,
The pressurizing chamber side end portion of the cylinder extends to the pressurizing chamber side from the metal contact seal portion, and the gap is formed between the outer peripheral surface of the extended portion and the inner wall surface of the pump housing. Is provided
Fluid pump. In the one according to claim 1 or 2,
A plunger seal mechanism is attached to the opening portion on the side opposite to the pressurizing chamber of the recess of the pump housing,
Surrounding the end of the cylinder opposite to the pressure chamber with the plunger seal mechanism,
The plunger is inserted through a seal element provided in the plunger seal mechanism to seal the outer periphery of the plunger,
A fluid pump provided with a seal portion for sealing between the plunger seal mechanism and the pump housing. A pump housing having a recess,
A cylinder assembled in the recess of the pump housing,
In what has
A metal contact seal portion is provided at a contact portion between the cylinder and the pump housing,
Except for the metal contact seal portion, a gap is provided between the radially opposing surfaces of the inner peripheral surface of the recess of the pump housing and the outer peripheral surface of the cylinder.
Fluid pump. What is described in claim 4,
Configured to pressurize the fluid in the pressurizing chamber with a plunger sliding on the cylinder;
The plunger protrudes from the pressurizing chamber side end of the cylinder into the pressurizing chamber.
Fluid pump. In any of claims 4 or 5,
A fluid seal mechanism mounted between the plunger and the counter-pressurizing chamber side opening of the recess of the pump housing;
A leaked fuel reservoir is formed between the fluid seal mechanism and the end of the cylinder, fuel leaked from the metal contact seal at the fuel reservoir, and leaked from between the cylinder and the plunger. Got fuel
Fluid pump.