JP2015148231A - High pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure pump capable of reducing the weight of a housing and capable of suppressing deformation of a cylinder.SOLUTION: A high pressure pump 1 includes a plunger 51, a cylinder 13, a passage forming member 15, a cover 31 and a supporting member 11. The cylinder 13 includes a pressurizing chamber 14 formed by an inner wall slidably supporting the reciprocatable plunger 51 and an outer wall of the plunger 51, a suction hole 141 communicated with the pressurizing chamber 14, and a discharge hole 142 connected with the pressurizing chamber 14. The passage forming member 15 includes suction passages 161 and 162 communicated with the suction hole 141 of the cylinder 13, and a discharge passage 163 communicated with the discharge hole 142 of the cylinder 13. The cover 31 is provided for storing the passage forming member 15. The supporting member 11 is connected with the cover 31, and forms a fuel gallery 33 into which fuel flows between the cover 31 and the supporting member 11.

Description

  The present invention relates to a high-pressure pump that sucks and pumps liquid.

  2. Description of the Related Art Conventionally, a high-pressure pump that sucks and pumps liquid by changing the volume of a pressurizing chamber by reciprocating a plunger is known. The high-pressure pump sucks liquid into the pressurizing chamber via the suction passage when the plunger is lowered, and pressurizes the liquid in the pressure chamber and discharges it from the discharge passage when the plunger is raised. For example, Patent Document 1 discloses a high-pressure pump that supplies fuel to an internal combustion engine. In this high-pressure pump, a pressurizing chamber, a suction passage, and a discharge passage are formed in a housing.

JP 2004-138062 A

  In recent years, high-pressure pumps are desired to cope with high pressures and large flow rates. Therefore, the housing that receives the pressure of the fuel in the pressurizing chamber is formed with a thickness to ensure rigidity that can withstand the pressure. The housing of the high-pressure pump disclosed in Patent Document 1 has a problem that it is complicated and heavy because a pressurizing chamber and a plurality of passages are formed in a solid cylindrical member.

  In order to solve the above problem, it is conceivable to form the housing with a plurality of members. For example, it is conceivable to form a housing by a cylinder having a pressurizing chamber, an upper housing coupled to the cylinder and having a suction passage and a discharge passage, and a lower housing coupled to the cylinder and the upper housing and functioning as a support member. According to this, the lower housing that does not directly receive the pressure of the fuel in the pressurizing chamber can be reduced in weight by reducing the thickness. Further, the upper housing can be reduced in weight by reducing the waste other than the portion forming the passage. Therefore, the housing becomes light.

  However, when the housing is constituted by a plurality of members as described above, for example, when the lower housing is coupled to the upper housing, or when the lower housing is coupled to another member, the lower housing is deformed, and the deformed lower housing is a cylinder. It is conceivable to press in the radial direction. When the cylinder is deformed in the radial direction by this pressing, the clearance between the cylinder and the plunger is narrowed, and the plunger may be seized.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a high-pressure pump capable of reducing the weight of the housing and suppressing the seizure of the plunger. .

The high-pressure pump according to the first aspect of the present invention includes a plunger, a cylinder, an upper housing, and a lower housing. The cylinder has a pressure chamber formed by an inner wall that slidably supports a plunger that can reciprocate and an outer wall of the plunger, a suction hole that communicates with the pressure chamber, and a discharge hole that is connected to the pressure chamber.
The upper housing includes a passage forming portion and a cover portion. The passage forming portion has a suction passage communicating with the suction hole of the cylinder and a discharge passage communicating with the discharge hole of the cylinder. The cover is provided to accommodate the passage forming part.
The lower housing is coupled to the cover. The lower housing forms a fuel gallery into which fuel flows in between the cover and the cover.

It is sectional drawing of the high pressure pump by 1st Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. FIG. 2 is an enlarged view illustrating in detail a joint portion of a support member, a cylinder, a passage forming member, and a cover in the high pressure pump of FIG. 1. It is sectional drawing of the high pressure pump by 2nd Embodiment of this invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.
(First embodiment)
A high-pressure pump according to a first embodiment of the present invention is shown in FIGS. The high-pressure pump 1 is a fuel pump that pressurizes fuel supplied from a fuel tank (not shown) by a low-pressure pump and discharges the pressurized fuel to a fuel rail. The high-pressure pump 1 includes a main body unit 10, a fuel supply unit 30, a plunger unit 50, a fuel suction unit 70, and a fuel discharge relief unit 90. In the following description, the upper side of FIGS. 1 and 2 is described as “upper”, and the lower side of FIG. 1 is described as “lower”.

The main body 10 includes a support member 11 as a “lower housing”, a cylinder 13, and a passage forming member 15 as a “passage forming portion”.
The support member 11 is integrally formed from the flange portion 111, the first fitting portion 112 and the second fitting portion 113. The flange portion 111 has a disk shape extending in the radially outward direction of the cylinder 13 and has a cylinder insertion hole 115 through which the cylinder 13 is inserted. The first fitting portion 112 as the “joining portion” is located in the radially outward direction of the cylinder 13 and has a cylindrical shape protruding upward from the flange portion 111. The second fitting portion 113 is positioned in the radially outward direction of the cylinder 13 and has a cylindrical shape that protrudes downward from the flange portion 13. The second fitting portion 113 is formed with a larger diameter than the first fitting portion 112. The flange portion 111 has a fuel flow hole 114 that penetrates in the thickness direction in the radially outward direction of the first fitting portion 112 and in the radially inward direction of the second fitting portion 113.
The support member 11 is made of a material having high rust resistance such as stainless steel.

The cylinder 13 includes a cylindrical portion 131 that slidably supports the plunger 51 and a bottom portion 132 that closes the upper end of the cylindrical portion 131. The cylinder 13 is inserted into the cylinder insertion hole 115 of the flange portion 111 from below. The cylinder portion 131 of the cylinder 13 has an annular protrusion 135 that protrudes radially outward at the lower side of the flange portion 111 and contacts the flange portion 111 in the axial direction. The flange portion 111 restricts the upward movement of the cylinder 13 when the annular protrusion 135 of the cylinder 13 comes into contact therewith.
The inner wall of the cylinder part 131, the inner wall of the bottom part 132, and the upper end surface 511 of the plunger 51 define the pressurizing chamber 14. The fuel in the pressurizing chamber 14 is pressurized by the plunger 51 that moves up in the cylinder 13 when the pressurizing chamber 14 is sealed.

The cylinder 13 has a suction hole 141 that penetrates the cylinder portion 131 in and out and communicates with the pressurizing chamber 14, and a discharge hole 142 that penetrates the cylinder portion 131 in and out and communicates with the pressurization chamber 14. The suction hole 141 and the discharge hole 142 are arranged symmetrically with respect to the axis of the plunger 51.
The cylinder 13 is increased in hardness by heat treatment such as quenching in order to suppress seizure and wear due to sliding of the plunger 51. This heat treatment may be applied only to the sliding surface 134 on which the plunger 51 slides, or may be applied to the entire cylinder 13.

  The passage forming member 15 is formed in a rectangular parallelepiped shape having a longitudinal shape in a direction perpendicular to the axis of the cylinder 13 as shown in FIG. A cylinder fitting hole 151 as a “first fitting hole” penetrating in the axial direction of the cylinder 13 is formed at the center in the longitudinal direction of the passage forming member 15. The cylinder 13 is, for example, press-fitted into the cylinder fitting hole 151 of the passage forming member 15. The cylinder 13 and the passage forming member 15 are coupled so that fuel pressurized in the pressurizing chamber 14 does not leak from between the outer wall of the cylinder 13 and the inner wall of the cylinder fitting hole 151.

  The passage forming member 15 communicates with the suction hole 141, extends to the opposite side of the pressurizing chamber 14 with respect to the suction hole 141, and is orthogonal to the longitudinal direction of the passage forming member 15 from the first suction passage 161. And a plurality of second suction passages 162 penetrating in the direction to go. The first suction passage 161 and the plurality of second suction passages 162 constitute an “intake passage”, and the fuel sucked into the pressurizing chamber 14 can flow therethrough.

The passage forming member 15 has a discharge passage 163 that communicates with the discharge hole 142 and extends to the opposite side of the pressurizing chamber 14 with respect to the discharge hole 142. The discharge passage 163 can discharge the fuel pressurized in the pressurizing chamber 14.
The passage forming member 15 is made, for example, by forming a cylinder fitting hole 151, a first suction passage 161, a second suction passage 162, and a discharge passage 163 in a rod-shaped material having a rectangular cross section. The passage forming member 15 constitutes an “upper housing” in the claims together with a cover 31 described later.

Next, the fuel supply unit 30 will be described.
The fuel supply unit 30 includes a cover 31, a pulsation damper 33, and a fuel inlet 35.
The cover 31 covers the passage forming member 15 and the upper end portion of the cylinder 13. The cover 31 has a bottomed cylindrical shape having a cover tube portion 312 positioned in the radially outward direction of the cylinder 13 and a cover bottom portion 311 that closes the upper end of the cover tube portion 312, that is, the side opposite to the support member 11. The cover cylinder part 312 forms a first cylindrical part 321, a multi-sided cylinder part 322, and a second cylindrical part 323 in order from the cover bottom part 311 side toward the support member 11 side.

The first cylindrical portion 321 and the second cylindrical portion 323 have a circular cross section perpendicular to the axial direction. The inner diameter of the first cylindrical part 321 is smaller than the inner diameter of the second cylindrical part 323.
The multi-sided cylinder part 322 has an octagonal cross section orthogonal to the axial direction. The outer surface of the multi-sided cylindrical part 322 is composed of four pairs of planes arranged parallel to each other and symmetrically with respect to the axis. The curved portion that connects the multi-side tube portion 322 and the first cylindrical portion 321 and the curved portion that connects the multi-side tube portion 322 and the second cylindrical portion 323 enhance the rigidity of the cover 31.

As shown in FIG. 3, the multi-sided cylindrical portion 322 includes a first through hole 325 that opens in a plane in the vicinity of the first suction passage 161 of the passage forming member 15 among the four pairs of planes, and the four pairs of planes. Of these, a second through hole 326 that opens in a plane near the discharge passage 163 of the passage forming member 15 and a third through hole 327 that opens in a plane adjacent to the plane in which the second through hole 326 opens are included. A suction valve body 72 is inserted into the first through hole 325 from the outside of the cover 31. A discharge valve body 91 is inserted into the second through hole 326 from the outside of the cover 31. A base end portion of a fuel inlet 35 that supplies fuel into the cover 31 is fitted in the third through hole 327.
The cover 31 is made by pressing a plate material such as stainless steel having high rust resistance. The cover 31 is formed to be thin as long as it serves to form the fuel gallery 32 therein.

  The cover 31 is welded to the flange portion 111 of the support member 11, the intake valve body 72, the discharge valve body 91, and the fuel inlet 35. Accordingly, a gap between the opening end on the support member 11 side and the flange portion 111, a gap between the first through hole 325 and the suction valve body 72, and a gap between the second through hole 326 and the discharge valve body 91. The gap and the gap between the third through hole 327 and the fuel inlet 35 are sealed in a liquid-tight manner. The flange portion 111 is coupled to the open end of the cover 31.

  A fuel gallery 32 defined by the inner wall of the cover 31, the outer wall of the flange portion 111 on the cover 31 side, and the outer wall of the passage forming member 15 and the cylinder 13 is formed in the cover 31. The fuel gallery 32 communicates with the second suction passage 162. The fuel flowing into the fuel gallery 32 from the fuel inlet 35 is supplied to the pressurizing chamber 14 via the second suction passage 162, the first suction passage 161, and the like.

The fuel gallery 32 is provided with a pulsation damper 33. The pulsation damper 33 is formed by joining the outer edges of two circular dish-shaped diaphragms 331 and 332. A gas having a predetermined pressure is sealed in the pulsation damper 33. The pulsation damper 33 is fixed to the inner wall of the first cylindrical portion 321 of the cover 31 so that the outer edge portion is sandwiched between the upper support body 341 and the lower support body 342.
The pulsation damper 33 is elastically deformed according to a change in the pressure of the fuel in the fuel gallery 32 to reduce the pressure pulsation of the fuel in the fuel gallery 32.

Next, the plunger unit 50 will be described.
The plunger unit 50 includes a plunger 51, an oil seal holder 52, a spring seat 53, a plunger spring 54, and the like.
The plunger 51 has a large-diameter portion 512 that is slidably supported by the cylindrical portion 131 of the cylinder 13 and a small-diameter portion 513 that is integrally formed below the large-diameter portion 512. The large diameter portion 512 can slide on the sliding surface 134 of the cylinder 13. The small diameter portion 513 passes through the oil seal holder 52.

  The oil seal holder 52 includes a press-fit portion 522 that fits to the inner wall of the second fitting portion 113 of the support member 11, and a base portion 521 that is formed integrally with the press-fit portion 522 and through which the small diameter portion 513 of the plunger 51 is inserted. . An annular seal 523 is provided between the cylindrical base 521 and the outer diameter surface of the small diameter portion 513. The seal 523 includes a Teflon (registered trademark) ring on the inner diameter side and an O-ring on the outer diameter side, and adjusts the thickness of the fuel oil film around the small diameter portion 513 of the plunger 51. As a result, fuel leakage to the engine is suppressed. An oil seal 525 is fixed to the tip portion of the base 521. The oil seal 525 adjusts the thickness of the oil film around the small diameter portion 513 of the plunger 51. Thereby, oil leakage is suppressed.

The spring seat 53 is provided at the lower end portion of the small diameter portion 513 of the plunger 51. The lower end portion of the small diameter portion 513 of the plunger 51 can abut on a tappet or the like (not shown). The tappet abuts the outer surface of a cam attached to a camshaft (not shown), and reciprocates in the axial direction according to the cam profile by the rotation of the camshaft.
One end of the plunger spring 54 is locked to the spring seat 53, and the other end is locked to the deep portion of the press-fit portion 522 of the oil seal holder 52. The plunger spring 54 functions as a return spring for the plunger 51 and urges the plunger 51 to contact the tappet.
The plunger unit 50 reciprocates the plunger 51 according to the rotation of the camshaft, and increases or decreases the volume of the pressurizing chamber 14.

Next, the fuel suction part 70 will be described.
The fuel suction portion 70 is for opening and closing the suction passage, and includes a suction valve portion 71 and an electromagnetic drive portion 81.
The intake valve portion 71 includes an intake valve body 72, a seat body 73, an intake valve member 74, a first spring holder 75, and the like.
The suction valve body 72 has a cylindrical shape and is coupled to the passage forming member 15 by being screwed into a screw hole formed in the inner wall of the first suction passage 161. The seat body 73 and the first spring holder 75 are sandwiched and fixed between the suction valve body 72 and the passage forming member 15. A suction chamber 711 formed in the seat body 73 communicates with the fuel gallery 32 through the second suction passage 162. The suction chamber 711 can communicate with the pressurization chamber 14 through the suction hole 141. A valve seat 731 (see FIG. 3) with which the suction valve member 74 can come into contact is formed on the pressure body 14 side of the seat body 73.

  The suction valve member 74 is provided so as to be able to contact and separate from the valve seat 731 on the pressure chamber 14 side with respect to the valve seat 731 of the seat body 73. The suction valve member 74 is separated from the valve seat 731 to connect the suction chamber 711 and the pressurization chamber 14, and is seated on the valve seat 731 to shut off the suction chamber 711 and the pressurization chamber 14. The first spring 76 accommodated in the first spring holder 75 biases the suction valve member 74 in the valve closing direction (left direction in FIG. 1).

The electromagnetic drive unit 81 includes a fixed core 83, a movable core 84, a needle 86, and the like.
The needle 86 is supported by a second spring holder 852 in the suction valve body 72 so as to be movable in the axial direction. The needle 86 moves toward the pressurizing chamber 14 to separate the suction valve member 74 from the valve seat 731. The movable core 84 is provided so as to be movable in the axial direction within the suction valve body 72, and is fixed to the end of the needle 86.
Inside the second spring holder 852, a second spring 85 that urges the needle 86 toward the pressurizing chamber 14 is provided. The second spring 85 biases the needle 86 in the valve opening direction with a force stronger than the force by which the first spring 76 biases the suction valve member 74 in the valve closing direction.

The fixed core 83 is provided on the side opposite to the suction valve member 74 with respect to the movable core 84. The coil 87 is provided around the fixed core 83. When the coil 87 is energized, a magnetic force is generated in the fixed core 83. The fixed core 83 with magnetic force attracts the movable core 84 against the urging force of the second spring 85. The needle 86 moves to the side opposite to the suction valve member 74 together with the movable core 84 sucked by the fixed core 83. As a result, the suction valve member 74 is seated and the suction valve portion 71 is closed.
The magnetic force of the fixed core 83 is lost when the power supply to the coil 87 is stopped. When the magnetic attraction force of the fixed core 83 disappears, the needle 86 moves to the opposite side of the fixed core 83 by the urging force of the second spring 85. Thereby, the suction valve member 74 is separated and the suction valve portion 71 is opened.

Next, the fuel discharge relief part 90 will be described.
The fuel discharge relief portion 90 includes a discharge valve body 91, a seat body 92, a discharge valve member 94, a relief valve member 96, and the like.
The discharge valve body 91 has a cylindrical shape and is coupled to the passage forming member 15 by being screwed into a screw hole formed in the inner wall of the discharge passage 163 of the passage forming member 15.

  The seat body 92 has a bottomed cylindrical shape and is fixed by being sandwiched between the discharge valve body 91 and the passage forming member 15. A discharge passage 95 and a relief passage 97 that is not in communication with the discharge passage 95 are formed on the bottom wall of the seat body 92. The discharge passage 95 opens to the outside of the wall surface of the bottom wall of the seat body 92 on the pressurizing chamber 14 side, and opens to the center of the wall surface of the bottom wall of the seat body 92 opposite to the pressurizing chamber 14. doing. The relief passage 97 opens in the center of the wall surface on the pressurizing chamber 14 side of the bottom wall of the seat body 92, and opens outward in the diameter on the wall surface on the opposite side of the pressurizing chamber 14 in the bottom wall of the seat body 92. doing.

The discharge valve member 94 is provided on the bottom wall of the seat body 92 on the side opposite to the pressurizing chamber 14 so as to contact and separate from the seat body 92. The discharge valve member 94 closes the discharge path 95 by contacting the seat body 92. The discharge valve spring 93 biases the discharge valve member 94 in the valve closing direction.
The relief valve member 96 is provided so as to come into contact with and separate from the seat body 92 on the pressure chamber 14 side of the bottom wall of the seat body 92. The relief valve member 96 closes the relief path 97 by contacting the seat body 92. The relief valve spring 98 biases the relief valve member 96 in the valve closing direction.

Next, the connecting portion of the support member 11, the cylinder 13, the passage forming member 15, and the cover 31 will be described in detail with reference to FIG.
The first fitting portion 112 of the support member 11 functions as a “joining portion”. The first fitting portion 112 of the support member 11 is an inner wall of the fitting hole 152 as a “second fitting hole” that opens to the lower side of the passage forming member 15 in the radially outward direction of the sliding surface 134 of the cylinder 13. It is press-fitted into. The flange portion 111 and the first fitting portion 112 of the support member 11 are disposed with a first annular gap 121 spaced from the outer wall of the tube portion 131 in the radially outward direction of the tube portion 131 of the cylinder 13.

The flange portion 111 of the support member 11 is in contact with the lower end surface 153 of the passage forming member 15 in the axial direction and is in contact with the annular protrusion 135 of the cylinder 13. The first fitting portion 112 of the support member 11 is disposed with a second annular gap 122 spaced from the bottom surface of the fitting hole 152 in the axial direction, and the flange portion 111 of the support member 11 is arranged in the radial direction of the cylinder 13. A third annular gap 123 is disposed with respect to the annular protrusion 135. The support member 11 is fixed so as not to move in the axial direction and the radial direction without contacting the cylinder 13 in the radial direction.
The end portion on the opening side of the cover 31 is welded to the flange portion 111 of the support member 11 in the radially outward direction of the sliding surface 134 of the cylinder 13. The flange portion 111 of the support member 11 has a screw insertion hole 116 through which a screw 101 used when fixing the high-pressure pump 1 to the engine 100 is inserted. The support member 11 is fastened to the engine 100 by a screw 101.

Next, a procedure for assembling the high-pressure pump will be described with reference to FIGS.
(I) First Press-Fitting Step In the first press-fitting step, the first fitting portion 112 of the support member 11 is press-fitted into the fitting hole 152 of the passage forming member 15. At this time, the support member 11 is press-fitted until the flange portion 111 contacts the lower end surface 153 of the passage forming member 15.
(II) Second Press-In Step In the second press-in step, the cylinder 13 is inserted into the cylinder insertion hole 115 from below the support member 11 and press-fitted into the cylinder fitting hole 151 of the passage forming member 115. At this time, the cylinder 13 is press-fitted until the annular protrusion 135 abuts on the support member 11 in the axial direction.

(III) Valve Mounting Step In the valve mounting step, first, the cover 31 is put on the outside of the passage forming member 15. Subsequently, the discharge valve body 91 is inserted into the second through hole 326 from the outside of the cover 31 and screwed into the passage forming member 15 in a state where the members constituting the fuel discharge relief portion are assembled in advance. Subsequently, the suction valve body 72 is inserted into the first through hole 325 from the outside of the cover 31 and screwed into the passage forming member 15. At this time, other members constituting the intake valve portion 71 are also assembled to the passage forming member 15 at the same time.
(IV) Welding Step In the welding step, first, the end portion on the opening side of the cover 31 and the flange portion 112 of the lower housing 11 are welded. Subsequently, the discharge valve body 91 and the cover 31 are welded, and the suction valve body 72 and the cover 31 are welded. These weldings are performed by, for example, laser welding.

  As described above, in the first embodiment, the housing of the high-pressure pump 1 includes the cylinder 13, the support member 11, the passage forming member 15, and the cover 31. The support member 11 is positioned in the radially outward direction of the cylinder 13, is formed in an annular shape so as to surround the outer wall of the cylinder 13, and is formed integrally with the flange portion 111 and the flange portion 111 that are coupled to the cover 31. 15 and a first fitting portion 112 coupled to the first fitting portion 112. The support member 11 is disposed with a first annular gap 121 in the radially outward direction of the cylinder 13.

In the high-pressure pump 1 configured as described above, the housing includes the cylinder 13, the support member 11, the passage forming member 15 and the cover 31. The supporting member 11 and the cover 31 that are not directly subjected to the fuel pressure in the pressurizing chamber 14 are lightened by reducing the thickness. The passage forming member 15 is made of a rod-shaped material having a rectangular cross section, and is reduced in weight by reducing the waste other than the portion forming each passage. Therefore, the housing of the high pressure pump 1 becomes light.
In addition, since the first annular gap 121 exists between the support member 11 and the cylinder 13, the support member 11 is separated from the cylindrical portion 131 of the cylinder 13 in the radial direction. Therefore, when the support member 11 is deformed by the connection between the support member 11 and the upper housing or the support member 11 and the engine 100, the support member 11 can be prevented from pressing the cylinder 13 in the radial direction. Therefore, deformation of the cylinder 13 is suppressed, and for example, it is possible to avoid the clearance between the cylinder 13 and the plunger 51 becoming narrow due to the deformation of the cylinder 13 and the plunger 51 being seized.

Moreover, in 1st Embodiment, the flange part 111 and 1st fitting part 112 which function as a connection part of the supporting member 11 are radially outward with respect to the sliding surface 134 of the cylinder part 131 which the plunger 51 can slide. To position.
As described above, even when the portion where the deformation amount of the support member 11 due to the coupling portion of the support member 11 and the other member is coupled is positioned radially outward with respect to the sliding surface 134 of the cylinder 13, the support member 11 is It is possible to avoid pressing the cylinder 13. Therefore, deformation of the cylinder 13 can be suppressed, and seizure of the plunger 51 can be avoided.

In the first embodiment, the passage forming member 15 and the cover 31 are formed separately from each other. The connecting portion of the support member 11 includes a first fitting portion 112 that is connected to the passage forming member 15 of the upper housing, and a flange portion 111 that is connected to the cover 31 of the upper housing.
According to this, when the support member 11 is deformed by the connection between the first fitting portion 112 of the support member 11 and the passage forming member 15 or the connection between the flange portion 111 of the support member 11 and the cover 31, the support member It can be avoided that 11 presses the cylinder 13 in the radial direction. Therefore, deformation of the cylinder 13 can be suppressed, and seizure of the plunger 51 can be avoided.

In the first embodiment, the first fitting portion 112 of the support member 11 has a cylindrical shape protruding from the flange portion 111 into the fitting hole 152. The first fitting portion 112 is fitted into the inner wall of the fitting hole 152 with an interference fit in the radially outward direction of the first annular gap 121.
According to this, when the support member 11 is deformed by the fitting of the first fitting portion 112 of the support member 11 and the passage forming member 15, the support member 11 is prevented from pressing the cylinder 13 in the radial direction. Can do. Therefore, deformation of the cylinder 13 can be suppressed, and seizure of the plunger 51 can be avoided.

Further, in the first embodiment, the first fitting portion 112 of the support member 11 is disposed with the second annular gap 122 spaced from the passage forming member 15 in the axial direction.
According to this, for example, a force acting on the passage forming member 15 from a valve device or a pipe connected to the passage forming member 15 is not easily transmitted to the support member 11. Therefore, it is possible to avoid the force transmitted from the passage forming member 15 to the support member 11 from acting on the cylinder 13. Therefore, deformation of the cylinder 13 can be suppressed, and seizure of the plunger 51 can be avoided.

In the first embodiment, the flange portion 111 of the support member 11 is welded to the cover 31 of the upper housing. In the first embodiment, the flange portion 111 of the support member 11 has a screw insertion hole 116 through which the screw 101 for fixing the support member 11 to the engine 100 is inserted.
As described above, even when the flange 111 of the support member 11 is welded to the cover 31 or when the support member 11 is screw-fastened to the engine 100, the support member 11 is greatly deformed. It is possible to avoid pressing 13. Therefore, deformation of the cylinder 13 can be suppressed, and seizure of the plunger 51 can be avoided.

In the first embodiment, the cylinder 13 has an annular protrusion 135 that protrudes outward in the radial direction on the side opposite to the pressurizing chamber 14 with respect to the first annular gap 121. The annular protrusion 135 abuts on the support member 11 in the axial direction. The support member 11 is disposed with a third annular gap 123 spaced from the protrusion of the cylinder 13 in the radial direction.
According to this, when the support member 11 deform | transforms, it can avoid that the support member 11 presses the protrusion of the cylinder 13 to radial direction. Therefore, deformation of the cylinder 13 can be suppressed, and seizure of the plunger 51 can be avoided.

(Second Embodiment)
A high-pressure pump according to a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 5, in the high-pressure pump 2 according to the second embodiment, the plunger 61 of the plunger portion 60 is a straight type plunger having the same outer diameter in the axial direction.
Also in the high-pressure pump 2 provided with such a plunger 61, as in the first embodiment, the support member 11 and the cover 31 that do not directly receive the fuel pressure in the pressurizing chamber 14 are lightened by reducing the thickness. ing. The passage forming member 15 is made of a rod-shaped material having a rectangular cross section, and is reduced in weight by reducing the waste other than the portion forming each passage. Therefore, the housing of the high pressure pump 1 becomes light.
In addition, since the first annular gap 121 exists between the support member 11 and the cylinder 13, the support member 11 is separated from the cylindrical portion 131 of the cylinder 13 in the radial direction. Therefore, when the support member 11 is deformed by the connection between the support member 11 and the upper housing or the support member 11 and the engine 100, the support member 11 can be prevented from pressing the cylinder 13 in the radial direction. Therefore, deformation of the cylinder 13 is suppressed, and for example, it is possible to avoid the clearance between the cylinder 13 and the plunger 51 becoming narrow due to the deformation of the cylinder 13 and the plunger 51 being seized.

(Other embodiments)
In other embodiments of the present invention, the passage forming member and the cover may be integrally formed with each other.
In another embodiment of the present invention, the first fitting portion and the flange portion of the support member do not have to be positioned radially outward with respect to the sliding surface of the cylinder portion of the cylinder. The 1st fitting part and flange part of a supporting member should just be located in the radial direction of the cylinder part of a cylinder.
In another embodiment of the present invention, the first fitting portion of the support member may be constituted by a fitting hole into which a cylindrical protrusion protruding from the passage forming member toward the support member is fitted.

In another embodiment of the present invention, the cylinder and the passage forming member may be coupled by a method other than press fitting. For example, it may be joined with other interference fits such as shrink fit or cold fit.
In another embodiment of the present invention, the passage forming member and the support member may be coupled by a method other than press fitting. For example, it may be coupled by other interference fit such as shrink fit or cold fit, or may be coupled by welding or brazing.
In another embodiment of the present invention, the first fitting portion of the support member may contact the bottom surface of the fitting hole of the passage forming member in the axial direction. Further, the flange portion of the support member may not abut on the lower end surface of the passage forming member in the axial direction.
In another embodiment of the present invention, the end portion on the opening side of the cover may be coupled to the flange portion of the support member by a method other than welding. For example, it may be coupled by an interference fit such as press fitting, shrink fitting or cold fitting.

In another embodiment of the present invention, the cylinder portion of the cylinder may not have an annular protrusion that contacts the support member in the axial direction.
In another embodiment of the present invention, the high-pressure pump may be a liquid pump that discharges liquid toward a device other than the fuel rail.
In another embodiment of the present invention, the suction passage and the discharge passage may not be arranged symmetrically with respect to the plunger axis. Further, the intake valve and the discharge valve need not be arranged symmetrically with respect to the axis of the plunger.
In another embodiment of the present invention, the pulsation damper may be disposed at a place other than the bottom of the cover instead of inside the bottom of the cover.
Thus, the present invention is not limited to the above-described embodiments, and can be applied to various forms without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 ... High pressure pump 11 ... Support member (lower housing)
111 ... Flange part 112 ... First fitting part (joint part)
121 ... 1st annular gap 13 ... Cylinder 131 ... Cylinder part 132 ... Bottom part 134 ... Sliding surface 14 ... Pressurizing chamber 141 ... Suction hole 142 ... Discharge Hole 15 ... passage forming member (passage forming portion, upper housing)
161 ・ ・ ・ First suction passage (suction passage)
162 ・ ・ ・ Second suction passage (suction passage)
163: Discharge passage 31: Cover (cover part, upper housing)
51, 61 ... Plunger

Claims (8)

A reciprocating plunger; and
A cylinder having an inner wall that slidably supports the plunger and a pressure chamber formed by the outer wall of the plunger, a suction hole communicating with the pressure chamber, and a discharge hole connected to the pressure chamber;
A passage forming portion having a suction passage communicating with the suction hole and a discharge passage communicating with the discharge hole, and an upper housing comprising a bottomed cylindrical cover provided so as to accommodate the passage formation portion;
A lower housing that is coupled to the cover and forms a fuel gallery into which the fuel flows;
A high pressure pump comprising:   The high-pressure pump according to claim 1, wherein an annular gap is provided between the cylinder and the lower housing.   The high-pressure pump according to claim 2, wherein the annular gap is formed between a portion of the cylinder that overlaps the lower housing in the axial direction and the lower housing.   The high pressure pump according to any one of claims 1 to 3, wherein the lower housing and the cover are joined by welding. The cover has a first through hole corresponding to the suction passage, and a second through hole corresponding to the discharge passage,
A fuel suction portion that is provided in the suction passage in a state of being inserted through the first through hole and through which the fuel sucked into the pressurizing chamber passes, and is disposed in the discharge passage in a state of being inserted through the second through hole. A high-pressure pump according to any one of claims 1 to 4, further comprising a fuel discharge portion that is provided and through which fuel discharged from the pressurizing chamber passes.   The high pressure according to claim 5, wherein the first through hole of the cover and the fuel suction portion, and the second through hole of the cover and the fuel discharge portion are joined by welding. pump.   The high-pressure pump according to any one of claims 1 to 6, further comprising a pulsation damper provided in the fuel gallery and capable of reducing pressure pulsation of fuel in the fuel gallery.   The high-pressure pump according to claim 7, wherein the pulsation damper is provided between a bottom portion of the cover and the passage forming portion.

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