High Pressure Pump

Abstract

To provide a high-pressure pump capable of easily suppressing the generation or transmission of vibration.SOLUTION: A high-pressure pump of the present invention includes a cylinder provided with a cylindrical hole, a plunger reciprocatingly slidably fitted in the cylindrical hole of the cylinder, a lifter interlockingly reciprocating the plunger, and a lifter guide that accommodates the lifter in an accommodation hole and guides the reciprocating movement of the lifter. The high-pressure pump further includes a damping resin layer provided on at least one of a vibration generation source and a vibration transmission path in the high-pressure pump, and the damping resin layer contains a heat-resistant resin and a damping filler that converts vibration energy into heat energy.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a high-pressure pump that pressurizes and discharges fuel. [Background technology]

[0002] A high-pressure pump that pressurizes fuel and supplies the pressurized fuel to an internal combustion engine is known. The high-pressure pump includes a cylinder and a plunger, and compresses the fuel in a pressurizing chamber defined by the cylinder and the plunger by reciprocating the plunger in a cylindrical bore of the cylinder.

[0003] As an example of a high-pressure pump, Patent Document 1 discloses a high-pressure pump including an intake valve for adjusting the amount of fuel drawn into a pressurizing chamber and an electromagnetic drive unit for controlling the opening and closing of the intake valve. The high-pressure pump disclosed in Patent Document 1 includes a housing having a fuel chamber and a pressurizing chamber communicating with the fuel chamber, a plunger reciprocatingly provided and capable of pressurizing the fuel in the pressurizing chamber, an intake valve that allows the flow of fuel between the fuel chamber and the pressurizing chamber when opened and blocks the flow of fuel between the fuel chamber and the pressurizing chamber when closed, a needle having one end located inside the housing and the other end located outside the housing and provided so as to be able to abut or connect to the intake valve, an electromagnetic drive unit provided on the other end side of the needle and drives the needle to open and close the intake valve, and a cylindrical member formed of a magnetic material in a cylindrical shape, with an outer diameter smaller than the outer diameter of a yoke of the electromagnetic drive unit, provided radially outside the needle so that its axis is along the axis of the needle, and connecting the housing and the electromagnetic drive unit.

[0004] In such a high-pressure pump structure, the electromagnetic drive unit is provided at an end of a cylindrical member protruding from a housing having a pressurizing chamber. When the electromagnetic drive unit opens and closes the intake valve, it generates an electromagnetic force, causing a needle abutting against the intake valve to reciprocate in the axial direction. Also, the plunger reciprocates in the axial direction to pressurize the fuel in the pressurizing chamber. Therefore, when the high-pressure pump is operated, the electromagnetic drive unit becomes a mass at the end of the cylindrical member and may vibrate relative to the housing. Such vibration may cause noise to be generated from the high-pressure pump. To address such a problem, the high-pressure pump described in Patent Document 1 further includes a vibration damping member that is provided radially outside the cylindrical member between the housing and the electromagnetic drive unit and that is capable of suppressing vibration of the electromagnetic drive unit relative to the housing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2018-128007 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the high-pressure pump described in Patent Document 1, since space is required to provide a vibration-damping member made of an elastic body or the like, the locations where the vibration-damping member can be provided are limited, and it may be difficult to provide the vibration-damping member at a location where vibration can be suppressed in the vibration source or the vibration transmission path. In some cases, it may be necessary to change the design of the existing structure of the high-pressure pump in order to secure space for providing the vibration-damping member.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a high-pressure pump that can easily suppress the generation or transmission of vibrations. [Means for solving the problem]

[0008] In order to solve the above problems, the high-pressure pump of the present invention is a high-pressure pump comprising a cylinder having a cylindrical bore, a plunger inserted into the cylindrical bore of the cylinder so as to be able to slide back and forth, a lifter that moves back and forth with the rotation of a drive cam and causes the plunger to move back and forth in tandem, and a lifter guide that accommodates the lifter in an accommodation hole and guides the reciprocating movement of the lifter, and is characterized in that the high-pressure pump further comprises a vibration-damping resin layer provided on at least one of a vibration generation source and a vibration transmission path in the high-pressure pump, and the vibration-damping resin layer contains a heat-resistant resin and a vibration-damping filler that converts vibration energy into thermal energy.

[0009] According to the high-pressure pump of the present invention, the generation or transmission of vibrations can be easily suppressed.

[0010] In the high pressure pump, the vibration-damping resin layer may be provided on at least one of an inner circumferential surface of the lifter guide and an outer circumferential surface of the lifter.

[0011] In the high pressure pump, the vibration-damping resin layer may be provided on an inner circumferential surface of the lifter guide.

[0012] The high-pressure pump may further include a lower housing that has a cylinder holding portion located radially outward of the cylinder and a flange portion protruding radially outward from the cylinder holding portion and supports the cylinder, and the vibration-damping resin layer may be provided on at least one of a fastening surface of the flange portion that faces the attached member and a seating surface opposite the fastening surface.

[0013] In the high pressure pump, the vibration-damping resin layer may have a thickness of 10 μm or more. Effect of the Invention

[0014] According to the present invention, the generation or transmission of vibrations can be easily suppressed. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view that shows a schematic diagram of a high-pressure pump according to a first embodiment. [Diagram 2] 2 is a cross-sectional view taken along line II-II in FIG. 1, with some components omitted. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 3 is a cross-sectional view showing a schematic view of a mounting structure of a flange portion of a lower housing material to an engine head in the high-pressure pump according to the first embodiment. FIG. [Diagram 5] 4 is an enlarged cross-sectional view of a fuel discharge relief portion of the high-pressure pump according to the first embodiment, and is an enlarged view of a portion indicated by an arrow IV in FIG. [Figure 6] 4 is an enlarged cross-sectional view of a fuel discharge relief portion of the high-pressure pump according to the first embodiment, and is an enlarged view of a portion indicated by an arrow V in FIG. [Figure 7] FIG. 6 is a cross-sectional view illustrating a high-pressure pump according to a second embodiment. [Figure 8] FIG. 1 is a cross-sectional view showing a typical example of a ball drop test machine. [Figure 9] 1 is a graph showing the sound pressure level of sound generated when a steel ball impacted against the thickness of the vibration-damping resin layer in the test pieces of Reference Examples 1 to 11 and Comparative Example 1. [Figure 10] 11 is a graph showing the acceleration level of vibration transmitted to the upper surface of the high-pressure pump in an engine in which the high-pressure pumps having vibration-damping resin layers formed at locations (1) to (4), (3)+(4), and (1)+(3)+(4) among the high-pressure pumps produced in Examples 1-1 to 3-7 are attached to the engine head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the high pressure pump of the present invention will be described. First, an overview of the high pressure pump according to the embodiments will be described by taking high pressure pumps according to first and second embodiments as examples.

[0017] (First embodiment) FIG. 1 is a cross-sectional view showing a schematic of a high-pressure pump according to a first embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, with some of the configuration omitted. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view showing a schematic of a mounting structure of a flange portion of a lower housing material to an engine head in a high-pressure pump according to a first embodiment. FIG. 5 is an enlarged cross-sectional view of a fuel discharge relief portion of a high-pressure pump according to a first embodiment, and is an enlarged view of a portion indicated by an arrow IV in FIG. 1. FIG. 6 is an enlarged cross-sectional view of a fuel discharge relief portion of a high-pressure pump according to a first embodiment, and is an enlarged view of a portion indicated by an arrow V in FIG. In the following description, the upper side of FIG. 1 is referred to as "upper" and the lower side of FIG. 1 is referred to as "lower".

[0018] As shown in FIG. 1, the high-pressure pump 1 according to the first embodiment is a fuel pump that pressurizes fuel supplied from a vehicle fuel tank (not shown) by a low-pressure pump and discharges the pressurized fuel to a fuel rail to which an injector is connected. The high-pressure pump 1 according to the first embodiment is attached to an accommodation hole 180 formed in an engine head 18 of an engine 9 of a vehicle. The high-pressure pump 1 includes a main body portion 10, a fuel supply portion 30, a plunger portion 50, a fuel intake portion 70, and a fuel discharge relief portion 90. The high-pressure pump 1 further includes a lifter 20 and a lifter guide 22. The lifter guide 22 according to the first embodiment is an inner wall 181 of the accommodation hole 180 formed in the engine head (cylinder head) 18.

[0019] Here, the main body 10 will be described. The main body 10 includes a lower housing 11 , a cylinder 13 , and an upper housing 15 . The lower housing 11 has a cylindrical cylinder holding portion 111 located radially outward of the cylinder 13, an annular flange portion 112 protruding radially outward from a lower portion of the cylinder holding portion 111, and a cylindrical engine fitting portion 113 having a larger diameter than the cylinder holding portion 111 and protruding from the flange portion 112 to the side opposite the cylinder holding portion 111. The flange portion 112 has one or more fuel flow holes 114 penetrating in the thickness direction radially outward of the cylinder holding portion 111 and radially inward of the engine fitting portion 113.

[0020] As shown in Figs. 1 to 4, the engine fitting portion 113 of the lower housing 11 is accommodated inside the accommodation hole 180 of the engine head 18, and the flange portion 112 of the lower housing 11 is placed on the fastening surface 18s of the engine head 18. A first vibration-damping resin layer 24a and a second vibration-damping resin layer 24b are provided on a fastening surface 112r of the flange portion 112 facing the engine head 18 and a seat surface 112s on the opposite side to the fastening surface 112r, respectively. The first vibration-damping resin layer 24a and the second vibration-damping resin layer 24b contain a heat-resistant resin and a vibration-damping filler that converts vibration energy into thermal energy. The lower housing 11 is fastened to the engine head 18 by bolts 101 inserted through the bolt insertion holes 117 of the flange portion 112 and the bolt insertion holes 187 of the engine head 18. A first vibration-damping resin layer 24a is disposed between the fastening surface 18s of the engine head 18 and the fastening surface 112r of the flange portion 112 (vibration transmission path). A second vibration-damping resin layer 24b is disposed between the seat surface 112s of the flange portion 112 and the head portion 101h of the bolt 101 (vibration transmission path).

[0021] The lower housing 11 is made by, for example, cutting a material in which the cylinder holding portion 111 and the engine fitting portion 113 have been formed into a cylindrical shape by forging, pressing, or the like, and then finishing the inner wall surface of the cylinder holding portion 111 and the inner wall surface and outer wall surface of the engine fitting portion 113. The lower housing 11 is made of a material having high rust resistance, such as stainless steel.

[0022] The cylinder 13 has a bottomed cylindrical shape with a cylindrical hole 130 that opens downward, and is press-fitted into the inner wall of the cylinder holding portion 111. The cylinder 13 protrudes radially outward from the lower side of the cylinder holding portion 111, forming an annular protrusion 135 that abuts against the cylinder holding portion 111 in the axial direction. The upward movement of the cylinder 13 is restricted by the annular protrusion 135 abutting against the cylinder holding portion 111. The cylinder 13 has a cylindrical inner wall 131 with a bottom that slidably supports the plunger 51. The inner wall 131, together with the upper end surface of the plunger 51, defines the pressurization chamber 14. When the pressurization chamber 14 is liquid-tightly sealed, the fuel in the pressurization chamber 14 is pressurized by the plunger 51 moving up inside the cylinder 13.

[0023] The cylinder 13 has a first communication hole 141 that penetrates from the pressurizing chamber 14 to the outer wall surface, and a second communication hole 142 that penetrates from the pressurizing chamber 14 to the outer wall surface in the opposite direction to the first communication hole 141. The first communication hole 141 and the second communication hole 142 are disposed symmetrically with respect to the axis of the plunger 51. The cylinder 13 is hardened by heat treatment such as quenching to prevent seizure and wear due to the sliding of the plunger 51. The heat treatment may be applied partially to the inner wall of the cylinder 13 on which the plunger 51 slides, or may be applied to the entire cylinder 13.

[0024] The upper housing 15 is separate from the lower housing 11, and is formed in a rectangular parallelepiped shape elongated in a direction perpendicular to the axial direction of the cylinder 13 as shown in Figs. 1 and 3. A press-fit hole 151 penetrating the upper housing 15 in the axial direction of the cylinder 13 is formed in the center of the longitudinal direction. The cylinder 13 is, for example, press-fitted into the press-fit hole 151 of the upper housing 15. This joins the cylinder 13 and the upper housing 15 so that the fuel pressurized in the pressurizing chamber 14 does not leak between the outer wall of the cylinder 13 and the inner wall of the press-fit hole 151. In the first embodiment, the upper housing 15 and the lower housing 11 abut against each other in the axial direction of the cylinder 13, but this abutment is not necessarily required.

[0025] The upper housing 15 has a stepped first suction hole 161 penetrating in the longitudinal direction of the upper housing 15 on the opposite side of the pressurizing chamber 14 with respect to the first communication hole 141, and a plurality of second suction holes 162 penetrating from the inner wall to the outer wall of the first suction hole 161. The first suction hole 161 and the plurality of second suction holes 162 form a suction passage communicating with the pressurizing chamber 14 via the first communication hole 141, and allow the flow of fuel drawn into the pressurizing chamber 14.

[0026] The upper housing 15 has a stepped first discharge hole 163 penetrating in the longitudinal direction of the upper housing 15 on the opposite side of the pressurization chamber 14 with respect to the second communication hole 142. The first discharge hole 163 constitutes a discharge passage communicating with the pressurization chamber 14 via the second communication hole 142, and is capable of discharging the fuel pressurized in the pressurization chamber 14. The upper housing 15 is formed, for example, by cutting a rod-shaped material having a rectangular cross section to form the press-fit hole 151, the first suction hole 161, the second suction hole 162, and the first discharge hole 163. The upper housing 15 is configured to be thin in thickness as long as it fulfills the role of forming the suction passage and the discharge passage.

[0027] Next, the fuel supply unit 30 will be described. As shown in FIGS. 1 to 3, the fuel supply unit 30 includes a cover 31, a pulsation damper 33, and a fuel inlet . The cover 31 accommodates the bottom of the cylinder 13 and the upper housing 15. The cover 31 is cylindrical with a bottom having an open end on the flange portion 112 side of the lower housing 11, and is composed of a cover bottom portion 311 and a cover tube portion 312. The cover bottom portion 311 closes the upper end portion of the cover tube portion 312. The cover tube portion 312 has, in order from the cover bottom portion 311 side in the axial direction, a first cylindrical portion 321, a multi-sided cylindrical portion 322, and a second cylindrical portion 323.

[0028] Although not shown, the first cylindrical portion 321 and the second cylindrical portion 323 are formed so that a cross section perpendicular to the axial direction is circular. The inner diameter of the first cylindrical portion 321 is smaller than the inner diameter of the second cylindrical portion 323. Although not shown, the multi-sided tube portion 322 is formed so that the cross section perpendicular to the axial direction is an octagonal shape. Here, an "octagonal shape" is a figure surrounded by eight line segments. Hereinafter, a multi-sided shape including the "octagonal shape" means a figure surrounded by multiple line segments, and includes shapes with rounded corners or chamfered corners, for example.

[0029] Although not shown, the outer wall surface of the multi-sided tube portion 322 is made up of four pairs of planes arranged parallel to each other and symmetrically about the axis. The curved portion connecting the multi-sided tube portion 322 and the first cylindrical portion 321 and the curved portion connecting the multi-sided tube portion 322 and the second cylindrical portion 323 increase the rigidity of the cover 31.

[0030] The multi-sided cylinder portion 322 has a first through hole 325 and a second through hole 326 that open into a pair of planes that face each other in the longitudinal direction of the upper housing 15 out of the four pairs of planes. The suction valve body 72 is inserted from the outside of the cover 31 into the first through hole 325 that penetrates inwardly and outwardly on the side opposite the pressurizing chamber 14 with respect to the first suction hole 161. The fuel discharge relief housing 91 is inserted from the outside of the cover 31 into the second through hole 326 that penetrates inwardly and outwardly on the side opposite the pressurizing chamber 14 with respect to the first discharge hole 163.

[0031] 3, the multi-sided cylinder portion 322 has a third through hole 327 that opens in a plane that is circumferentially adjacent to the plane in which the second through hole 326 opens. A base end portion of a fuel inlet 35 that supplies fuel into the cover 31 is fitted into the third through hole 327. The cover 31 is formed by pressing a highly rust-resistant plate material such as stainless steel into a cylindrical shape with a bottom, and then forming the first through hole 325, the second through hole 326, and the third through hole 327 by, for example, cutting. The cover 31 is formed to have a thin wall thickness as long as it fulfills the role of forming the fuel gallery 32 inside.

[0032] The cover 31 is joined to each member by, for example, welding so that a gap between the open end of the cover 31 and the flange portion 112, a gap between the first through hole 325 and the intake valve body 72, a gap between the second through hole 326 and the fuel discharge relief housing 91, and a gap between the third through hole 327 and the fuel inlet 35 are liquid-tightly sealed. A fuel gallery 32 is formed inside the cover 31, the fuel gallery 32 being a space defined by an inner wall of the cover 31, an outer wall of the flange portion 112 on the cover 31 side, and the outer walls of the upper housing 15 and the cylinder 13. The fuel gallery 32 is in communication with the second intake hole 162. The fuel flowing into the fuel gallery 32 from the fuel inlet 35 is supplied to the pressurizing chamber 14 via the second intake hole 162, etc.

[0033] The fuel gallery 32 accommodates a pulsation damper 33. The pulsation damper 33 is formed by joining the outer edges of two circular dish-shaped diaphragms 331 and 332. The pulsation damper 33 is fixed to the inner wall of the first cylindrical portion 321 of the cover 31 such that the outer edge is sandwiched between an upper support 341 and a lower support 342. Although not shown, a plurality of fuel flow passages are formed between the inner wall of the first cylindrical portion 321 and the upper support 341 that fits therewith. Although not shown, fuel is supplied to the space above the pulsation damper 33 via the fuel flow passages. A gas of a predetermined pressure is sealed inside the pulsation damper 33. The pulsation damper 33 reduces pressure pulsation of the fuel in the fuel gallery 32 by elastically deforming in response to pressure changes of the fuel in the fuel gallery 32. The cover 31 functions as a housing member for the pulsation damper 33.

[0034] Next, the plunger portion 50 will be described. As shown in FIGS. 1 and 2, the plunger portion 50 includes a plunger 51, an oil seal holder 52, a spring seat 53, a plunger spring 54, and the like. The plunger 51 is fitted into the cylindrical bore 130 of the cylinder 13 so as to be slidable back and forth in the axial direction, and is supported by the inner wall 131 of the cylinder 13 so as to be slidable in the axial direction. The plunger 51 forms a large diameter portion 512 and a small diameter portion 513. The large diameter portion 512 located on the pressurizing chamber 14 side slides on the inner wall 131 of the cylinder 13. The small diameter portion 513 located on the opposite side of the pressurizing chamber 14 with respect to the large diameter portion 512 is inserted into the oil seal holder 52.

[0035] The oil seal holder 52 is provided at the open end of the cylinder 13 and has a base 521 located radially outside the small diameter portion 513 of the plunger 51, and a press-fit portion 522 that is press-fitted into the inner wall of the engine fitting portion 113. The base 521 has a ring-shaped seal 523 inside. The seal 523 is made up of a Teflon (registered trademark) ring on the inside diameter and an O-ring on the outside diameter. The seal 523 adjusts the thickness of the fuel oil film around the small diameter portion 513 of the plunger 51, thereby preventing fuel from leaking into the engine. The base 521 also has an oil seal 525 at its tip. The oil seal 525 regulates the thickness of the oil film around the small diameter portion 513 of the plunger 51, thereby preventing oil from leaking.

[0036] The press-fit portion 522 is a portion that protrudes cylindrically around the base portion 521, and the cylindrical portion has a U-shaped vertical cross section. A recess 526 corresponding to the press-fit portion 522 is formed in the lower housing 11. The oil seal holder 52 is press-fitted such that the press-fit portion 522 is in pressure contact with the inner wall of the recess 526.

[0037] The spring seat 53 is provided at the lower end of the plunger 51. One end of the plunger spring 54 is engaged with the spring seat 53, and the other end is engaged with a deep portion of the press-fit portion 522 of the oil seal holder 52. As a result, the plunger spring 54 functions as a return spring for the plunger 51, and urges the plunger 51 to abut against the lifter (tappet) 20.

[0038] The high-pressure pump 1 is attached to the engine 9 such that the engine fitting portion 113 of the lower housing 11, the cylinder 13, the plunger 51 of the plunger portion 50, the oil seal holder 52, the spring seat 53, the plunger spring 54, etc. are accommodated inside the accommodation hole 180 of the engine head 18 of the engine 9. Here, a rubber annular seal member 115 is provided between the engine fitting portion 113 and the inner wall 181 of the accommodation hole 180. This maintains the gap between the engine fitting portion 113 and the inner wall 181 of the accommodation hole 180 liquid-tight or air-tight.

[0039] The lifter 20 has a bottomed cylindrical shape and is accommodated in an accommodating hole 180 of the engine head 18. The lifter 20 is capable of reciprocating axially inside the accommodating hole 180, and an inner wall (lifter guide) 181(22) of the accommodating hole 180 guides the reciprocating movement of the lifter 20. A third vibration-damping resin layer 24c is provided on an inner wall surface (inner peripheral surface of the lifter guide, vibration generating source) 181s of the accommodating hole 180. The third vibration-damping resin layer 24c contains a heat-resistant resin and a vibration-damping filler that converts vibration energy into thermal energy.

[0040] The lower end of the plunger 51, that is, the end of the small diameter portion 513 of the plunger 51 opposite to the large diameter portion 512, is in contact with the bottom of the lifter 20. The roller 3 and the driving cam 7 of the camshaft 5 are located on the opposite side of the plunger 51 of the lifter 20. The roller 3 rotatably supports the lifter 20. The driving cam 7 rotates together with the camshaft 5 which rotates in conjunction with the drive shaft of the engine 9. With the rotation of the driving cam 7, the roller 3 reciprocates in the axial direction of the lifter 20 while rolling, so that the lifter 20 reciprocates in the axial direction. As a result, the plunger 51 is pressed by the lifter 20 while being biased by the plunger spring 54, so that the plunger 51 reciprocates in the cylindrical hole 130 of the cylinder 13 in conjunction with the plunger 51. At this time, the volume of the pressurizing chamber 14 changes periodically due to the movement of the large diameter portion 512 of the plunger 51. The driving cam 7 has four cam lobes. Therefore, when the drive cam 7 rotates once, the plunger 51 reciprocates in the bore 130 of the cylinder 13 four times.

[0041] Next, the fuel intake section 70 will be described. As shown in FIGS. 1 and 3, the fuel suction section 70 is capable of opening and closing the suction passage, and includes a suction valve section 71 and an electromagnetic driver 81. The suction valve portion 71 is made up of a suction valve body 72, a seat body 73, a suction valve member 74, a first spring holder 75, and the like. The cylindrical intake valve body 72 is joined to the upper housing 15 by being screwed into a threaded hole formed in the first intake hole 161. A intake chamber 711 is formed inside the intake valve body 72. The intake chamber 711 is connected to the fuel gallery 32 via the second intake hole 162. A substantially cylindrical seat body 73 is provided in the intake chamber 711. A valve seat 731 against which the intake valve member 74 can abut is formed on the pressurizing chamber 14 side of the seat body 73.

[0042] The suction valve member 74 is provided inside the seat body 73 so as to be able to come into contact with and separate from the valve seat 731. When the suction valve member 74 moves away from the valve seat 731, it communicates between the suction chamber 711 and the pressurizing chamber 14, and when the suction valve member 74 sits on the valve seat 731, it isolates the suction chamber 711 from the pressurizing chamber 14. The first spring holder 75 is provided on the pressurization chamber 14 side with respect to the suction valve member 74, and accommodates a first spring 76 inside for urging the suction valve member 74 in the valve closing direction (leftward in FIG. 1).

[0043] The electromagnetic drive unit 81 is composed of a fixed core 83, a movable core 84, a needle 86, and the like. Cylindrical movable core 84 is provided within intake valve body 72 so as to be movable in the axial direction, and is fixed to one end of a needle 86 that is disposed coaxially with intake valve member 74. Needle 86 is supported by a second spring holder 852 so as to be movable in the axial direction, and is provided so as to be able to come into contact with intake valve member 74. A second spring 851 that urges the needle 86 toward the intake valve member 74 is provided inside the second spring holder 852. The second spring 851 urges the needle 86 in the valve opening direction with a force stronger than the force with which the first spring 76 urges the intake valve member 74 in the valve closing direction.

[0044] Fixed core 83 is provided on the opposite side of movable core 84 to intake valve member 74. Coil 87 is provided around fixed core 83. When current is applied to coil 87, a magnetic force is generated in fixed core 83. The magnetically charged fixed core 83 attracts movable core 84 against the biasing force of second spring 851. Needle 86 moves to the opposite side to intake valve member 74 together with movable core 84, which is attracted to fixed core 83. As a result, intake valve member 74 is seated and intake valve portion 71 is closed. The magnetic force of fixed core 83 is lost when current is cut off to coil 87. When the magnetic attractive force of fixed core 83 is lost, needle 86 moves to the opposite side from fixed core 83 due to the biasing force of second spring 88. This causes intake valve member 74 to lift off its seat, and intake valve portion 71 to open.

[0045] Next, the fuel discharge relief portion 90 will be described. As shown in FIGS. 1, 3, 5, and 6, the fuel discharge relief portion 90 includes a fuel discharge relief housing 91, a discharge valve body 92, a discharge valve member 94, a relief valve member 96, and the like. The fuel discharge relief housing 91 is formed in a cylindrical shape, and is joined to the upper housing 15 by being screwed into a threaded hole formed in the first discharge hole 163 of the upper housing 15. The fuel discharge relief housing 91 accommodates a discharge valve body 92, a discharge valve member 94, a relief valve member 96, and the like.

[0046] The discharge valve body 92 has a cylindrical shape with a bottom, is provided in the fuel discharge relief housing 91, and opens to the pressurization chamber 14 side. A discharge passage 95 and a relief passage 97 not communicating with the discharge passage 95 are formed in the bottom wall of the discharge valve body 92. The discharge passage 95 opens to the radially outer side of the wall surface of the bottom wall of the discharge valve body 92 facing the pressurization chamber 14, and also opens to the center of the wall surface of the bottom wall of the discharge valve body 92 opposite to the pressurization chamber 14. The relief passage 97 opens to the center of the wall surface of the bottom wall of the discharge valve body 92 facing the pressurization chamber 14, and also opens to the radially outer side of the wall surface of the bottom wall of the discharge valve body 92 opposite to the pressurization chamber 14.

[0047] The discharge valve member 94 is provided adjacent to the bottom wall of the discharge valve body 92 on the opposite side to the pressurization chamber 14 inside the fuel discharge relief housing 91. A discharge valve spring holder 945 is provided on the opposite side of the discharge valve member 94 to the pressurization chamber 14. The discharge valve member 94 is urged toward the valve seat 93 on the bottom wall of the discharge valve body 92 by a discharge valve spring 943 interposed between the discharge valve member 94 and the discharge valve spring holder 945, and is capable of opening and closing the discharge passage 95.

[0048] The relief valve member 96 is provided adjacent to the pressurization chamber 14 side of the bottom of the discharge valve body 92 inside the fuel discharge relief housing 91. The relief valve member 96 is urged toward the bottom of the discharge valve body 92 by a relief valve spring 963 provided between the relief valve member 96 and a relief valve spring holder 965 on the pressurization chamber 14 side, and is capable of opening and closing the relief passage 97.

[0049] Next, the operation of the high pressure pump 1 will be described. (I) Inhalation stroke When the plunger 51 moves down from the top dead center to the bottom dead center due to the rotation of the camshaft 5, the volume of the pressurizing chamber 14 increases and the pressure of the fuel in the pressurizing chamber 14 decreases. At this time, the discharge passage 95 is blocked by the discharge valve member 94. Also, when the current supply to the coil 87 is stopped, the needle 86 receives the biasing force of the second spring 85 and moves toward the suction valve member 74. This causes the needle 86 to press the suction valve member 74, and the suction valve portion 71 opens. As a result, fuel is sucked into the pressurizing chamber 14 from the suction chamber 711 via the first communication hole 141.

[0050] (II) Metering process When the plunger 51 rises from the bottom dead center to the top dead center due to the rotation of the camshaft 5, the volume of the pressurizing chamber 14 decreases. At that time, the coil 87 is de-energized until a predetermined time, and the intake valve portion 71 is opened. As a result, a portion of the low-pressure fuel that was sucked into the pressurizing chamber 14 during the intake stroke is returned to the fuel supply side. Then, by energizing coil 87 at a predetermined time while plunger 51 is ascending, a magnetic attractive force is generated between fixed core 83 and movable core 84. When this magnetic attractive force becomes greater than the resultant force obtained by subtracting the biasing force of first spring 76 from the biasing force of second spring 851, movable core 84 and needle 86 move toward fixed core 83. This releases the pressing force of needle 86 against suction valve member 74. As a result, suction valve member 74 seats on valve seat 731 of seat body 73, and suction valve portion 71 closes.

[0051] (III) Pressurization process After the suction valve portion 71 closes, the volume of the pressurization chamber 14 decreases as the plunger 51 rises, and the pressure of the fuel in the pressurization chamber 14 increases. When the force acting on the discharge valve member 94 due to the fuel pressure in the pressurization chamber 14 becomes greater than the sum of the biasing force of the discharge valve spring 943 and the force acting on the discharge valve member 94 due to the fuel pressure on the fuel discharge port 99 side, the discharge valve member 94 opens. As a result, the pressurized fuel in the pressurization chamber 14 is discharged from the fuel discharge port 99 via the second communication hole 142, the first discharge hole 163, etc. The high-pressure pump 1 repeats a suction stroke, a metering stroke, and a pressurizing stroke, metering the amount of sucked fuel, and pressurizing the fuel, and discharging it from a fuel discharge port 99 .

[0052] In the high pressure pump 1 according to the first embodiment, the third vibration-damping resin layer 24c is provided on the inner wall surface (inner peripheral surface of the lifter guide, vibration generating source) 181s of the accommodation hole 180 of the engine head 18. Therefore, when the lifter 20 moves back and forth in the axial direction inside the accommodation hole 180 and the inner wall (lifter guide) 181 (22) of the accommodation hole 180 guides the reciprocating movement of the lifter 20, the outer peripheral surface 20s of the lifter 20 does not directly contact and slide against the inner wall surface 181s of the accommodation hole 180, but contacts and slides against the third vibration-damping resin layer 24c provided on the inner wall surface 181s of the accommodation hole 180. This makes it possible to avoid vibrations occurring due to the outer peripheral surface 20s of the lifter 20 directly contacting and sliding against the inner wall surface 181s of the accommodation hole 180. In addition, the third vibration-damping resin layer 24c can suppress the transmission of vibrations generated by, for example, the reciprocating movement of the plunger 51 in response to the rotation of the camshaft 5. This can suppress, for example, the radiation of these vibrations or noise caused by the vibrations to the outside of the vehicle or the passenger compartment via the engine head 18, etc.

[0053] Moreover, in the high pressure pump 1 according to the first embodiment, the first vibration-damping resin layer 24a is disposed between the fastening surface 18s of the engine head 18 and the fastening surface 112r of the flange portion 112 (vibration transmission path). Therefore, for example, it is possible to suppress the transmission of vibrations generated by the reciprocating movement of the plunger 51 in response to the rotation of the camshaft 5 between the flange portion 112 and the engine head 18. This, for example, can suppress the emission of these vibrations or noises caused by the vibrations as noise to the outside of the vehicle or the outside of the vehicle, such as the passenger compartment, via the engine head 18, etc. Also, the second vibration-damping resin layer 24b is disposed between the seat surface 112s of the flange portion 112 and the head 101h of the bolt 101 (vibration transmission path). Therefore, for example, it is possible to suppress the transmission of these vibrations between the flange portion 112 and the bolt 101. This, for example, can suppress the emission of these vibrations or noises caused by the vibrations as noise to the outside of the vehicle or the outside of the vehicle, such as the passenger compartment, via the engine head 18, etc.

[0054] Second embodiment Regarding the high pressure pump according to the second embodiment, the points different from the first embodiment will be described. Fig. 7 is a cross-sectional view showing a schematic diagram of a high-pressure pump according to a second embodiment. In the following description, the upper side of Fig. 7 will be referred to as "top" and the lower side of Fig. 7 will be referred to as "bottom".

[0055] As shown in Fig. 7, in the high-pressure pump 1 according to the second embodiment, a fourth vibration-damping resin layer 24d is provided on the outer peripheral surface (vibration generating source) 20s of the lifter 20. The fourth vibration-damping resin layer 24d contains a heat-resistant resin and a vibration-damping filler that converts vibration energy into thermal energy. However, unlike the first embodiment, no vibration-damping resin layer is provided on the inner wall surface (inner peripheral surface of the lifter guide) 181s of the accommodation hole 180 of the engine head 18. The other configurations of the high-pressure pump 1 according to the second embodiment are similar to those of the first embodiment.

[0056] In the high pressure pump 1 according to the second embodiment, unlike the first embodiment, when the lifter 20 reciprocates in the axial direction inside the accommodation hole 180 of the engine head 18, and the inner wall (lifter guide) 181 (22) of the accommodation hole 180 guides the reciprocating movement of the lifter 20, the fourth vibration-damping resin layer 24d provided on the outer peripheral surface 20s of the lifter 20 comes into contact with and slides on the inner wall surface (inner peripheral surface of the lifter guide) 181s of the accommodation hole 180. This makes it possible to avoid the outer peripheral surface 20s of the lifter 20 coming into direct contact with and sliding on the inner wall surface 181s of the accommodation hole 180, thereby preventing vibration from being generated. In addition, for example, the fourth vibration-damping resin layer 24d can suppress the transmission of vibration generated by the reciprocating movement of the plunger 51 in response to the rotation of the camshaft 5. This makes it possible to suppress, for example, the radiation of these vibrations or noise caused by the vibrations to the outside of the vehicle or the room via the engine head 18, etc.

[0057] (Action and effect) Therefore, according to the high pressure pump according to the embodiment, as in the first and second embodiments, the vibration generation or transmission can be suppressed by providing a vibration-damping resin layer on at least one of the vibration generation source, such as the inner circumferential surface of the lifter guide or the outer circumferential surface of the lifter, and the vibration transmission path. In addition, since a thin and lightweight vibration-damping resin layer that can be formed to a thickness of about several tens of μm is used as the vibration-damping member, the location where the vibration-damping member is provided is not limited, and there is little need to change the design of the existing structure of the high pressure pump to ensure space for providing the vibration-damping member. Therefore, the generation or transmission of vibration can be easily suppressed. Therefore, it is possible to easily suppress the radiation of vibration or noise caused by vibration to the outside of the vehicle or the outside of the system, such as the living room, through the attached member, such as the engine head. In addition, the vibration-damping member can be provided in a narrow space that can be a vibration generation source, such as the inner circumferential surface of the lifter guide or the outer circumferential surface of the lifter. This makes it easy to take measures against the vibration generation source.

[0058] Furthermore, while conventional vibration-damping members made of elastic bodies or the like are likely to deteriorate due to heat and may experience performance degradation due to creep or the like over long-term use, the high-pressure pump according to the embodiment can avoid these problems by using a vibration-damping resin layer as the vibration-damping member. Also, according to the high-pressure pump according to the embodiment, the vibration-damping resin layer is thinner and lighter than conventional vibration-damping members made of elastic bodies or the like, and therefore degradation of other performances such as fuel efficiency can be suppressed.

[0059] Next, the high pressure pump according to the embodiment will be described in detail.

[0060] 1.High pressure pump The high-pressure pump comprises a cylinder having a cylindrical hole, a plunger inserted into the cylindrical hole of the cylinder so as to be able to slide back and forth, a lifter that moves back and forth with the rotation of a drive cam and causes the plunger to move back and forth in tandem, and a lifter guide that accommodates the lifter in an accommodation hole and guides the reciprocating movement of the lifter.

[0061] The high-pressure pump is not particularly limited as long as it is as described above, but may be a pump like the high-pressure pumps according to the first and second embodiments, which has a cylinder holding portion located radially outward of the cylinder and a flange portion protruding radially outward from the cylinder holding portion, and further includes a lower housing supporting the cylinder.

[0062] The lifter guide is not particularly limited as long as it guides the reciprocating movement of the lifter, but may be, for example, the inner wall of a accommodating hole formed in the engine head like the lifter guides of the first and second embodiments, or it may be, for example, a member separate from the engine head, having a cylindrical inner wall that guides the reciprocating movement of the lifter, and being accommodated in the accommodating hole in the engine head.

[0063] 2. Vibration-damping resin layer The high-pressure pump further includes a vibration-damping resin layer provided on at least one of a vibration generating source and a vibration transmission path in the high-pressure pump, The vibration-damping resin layer includes a heat-resistant resin and a vibration-damping filler that converts vibration energy into thermal energy.

[0064] The high-pressure pump is not particularly limited as long as it has the vibration-damping resin layer as described above, but it is preferable that the vibration-damping resin layer is provided on at least one of the inner circumferential surface of the lifter guide and the outer circumferential surface of the lifter, as in the third and fourth vibration-damping resin layers according to the first embodiment. The inner circumferential surface of the lifter guide and the outer circumferential surface of the lifter are vibration generating sources that generate vibrations by directly contacting and sliding against each other during the reciprocating movement of the lifter, so that the generation of vibration itself can be suppressed by providing a vibration-damping resin layer on at least one of these surfaces. Among them, the high-pressure pump is preferably provided with a vibration-damping resin layer provided on the inner circumferential surface of the lifter guide. During the reciprocating movement of the lifter, the outer circumferential surface of the lifter always slides as a whole, whereas the sliding portion of the inner circumferential surface of the lifter guide changes according to the movement of the lifter. Therefore, compared to the high-pressure pump provided with a vibration-damping resin layer provided on the outer circumferential surface of the lifter, wear of the vibration-damping resin layer is suppressed, and the performance of the vibration-damping resin layer is easily maintained.

[0065] The high-pressure pump may include, as the vibration-damping resin layer, a vibration-damping resin layer provided on at least one of the fastening surface of the flange portion facing the attached member and the seating surface opposite the fastening surface, like the first and second vibration-damping resin layers according to the first embodiment. Here, the "attached member" refers to a member to which the high-pressure pump is attached, such as an engine head of an engine of a vehicle or the like.

[0066] The thickness of the vibration-damping resin layer is not particularly limited as long as it can suppress vibration, but is preferably, for example, 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more. This is because a sufficient vibration transmission blocking effect can be obtained. The thickness of the vibration-damping resin layer is preferably, for example, 400 μm or less, more preferably 200 μm or less, particularly preferably 100 μm or less, and particularly preferably 50 μm or less. This is because the improvement in the vibration blocking effect becomes saturated, and the formation of the layer by coating becomes easy.

[0067] The heat-resistant resin contained in the vibration-damping resin layer is not particularly limited as long as it has a heat distortion temperature of 100°C or more, but is preferably one having a heat distortion temperature of 150°C or more. Examples of heat-resistant resins include, but are not limited to, polyamideimide resins, polyimide resins, phenolic resins, epoxy resins, polyethersulfone resins, polyphenylsulfide resins, etc. From the viewpoints of workability when forming a coating and heat resistance against heat generation due to friction, polyamideimide resins are more preferable. These heat-resistant resins may be used alone or in combination of two or more types.

[0068] The vibration-damping filler contained in the vibration-damping resin layer converts vibration energy into thermal energy. The vibration-damping filler is not particularly limited, but can be roughly divided into a material that is easily deformed at a low elastic modulus and a material that is easily dissipated inside. A material that is easily deformed at a low elastic modulus is, more specifically, a material that is solid but has both remarkably elastic properties and viscous properties. All materials have both elastic properties and viscous properties, but a material that is easily deformed at a low elastic modulus has both of these properties remarkably. For this reason, by including a material that is easily deformed at a low elastic modulus in the vibration-damping resin layer, the rubber elasticity of the vibration-damping resin layer itself in the normal temperature range can be increased. As a result, it is considered that the vibration input from the outside can be effectively absorbed by the vibration-damping resin layer and converted into thermal energy, thereby effectively blocking the transmission of vibration. On the other hand, a material that is easily dissipated inside has the effect of attenuating vibration by diffusely reflecting vibrations at the air layer present in the material and converting them into thermal energy. For this reason, it is believed that if a material that easily dissipates energy inside is contained in the vibration-damping resin layer, the vibration-damping resin layer can effectively block the transmission of vibration.

[0069] Examples of materials that are easily deformed with a low modulus of elasticity include thermoplastic elastomers, urethane-based compounds, polyethylene-based compounds, ester copolymers, and rubber-based materials. Thermoplastic elastomers generally have the properties of rubber at room temperature, and have the same performance as thermoplastic plastics at high temperatures. Examples of thermoplastic elastomers include styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, urethane-based thermoplastic elastomers, ester-based thermoplastic elastomers, and amide-based thermoplastic elastomers. Examples of these are listed in, for example, JP 2016-113614 A and JP 2017-197733 A. Examples of urethane-based compounds include urethane resins. Examples of these are listed in, for example, JP 8-183945 A. Examples of polyethylene-based compounds include ethylene homopolymers and copolymers of ethylene and α-olefin monomers. Examples of these are given in, for example, JP 2009-532570 A and the like. Examples of ester copolymers include acrylic acid ester copolymers and the like. Examples of these are given in, for example, JP 3209499 A and the like. Examples of rubber-based materials include butyl rubber, fluororubber and the like. Examples of these are given in, for example, JP 2009-236172 A and the like.

[0070] Examples of materials in which energy dissipation is likely to occur include microcapsule-based materials and low-density materials. Examples of microcapsule-based materials include thermally expandable microcapsules that contain a vaporized substance that expands when a certain temperature range is reached inside a shell made of a thermoplastic polymer. These examples are listed in JP 2013-18855 A and the like. Examples of low-density materials include, for example, materials that contain an air layer inside the material in general, and specifically, for example, foamed materials, porous bodies, nonwoven fabrics, layered compounds, and the like. These examples are listed in, for example, JP 3-221173 A and JP 4203589 A and the like. The vibration-damping fillers listed above may be used alone or in combination of two or more types.

[0071] The vibration-damping resin layer may contain optional components such as solid lubricants and hard particles in addition to the heat-resistant resin and the vibration-damping filler. This is because the vibration-damping resin layer can be provided with properties such as wear resistance, seizure resistance, and low friction characteristics. The solid lubricants are not particularly limited, and examples thereof include polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS2), graphite, and the like. These solid lubricants may be used alone or in combination of two or more. The hard particles are not particularly limited, and examples thereof include alumina (Al2O3), silica, and the like. These hard particles may be used alone or in combination of two or more.

[0072] The volume ratio of the vibration-damping filler to the total volume of the heat-resistant resin and the vibration-damping filler in the vibration-damping resin layer is not particularly limited, but is preferably, for example, 20% by volume or more and 80% by volume or less, and more preferably, 40% by volume or more and 60% by volume or less. By being above the lower limit of these ranges, vibration energy can be converted into heat energy more efficiently by the filler. Also, by being below the upper limit of these ranges, durability as a resin coating (e.g., abrasion resistance, adhesion, etc.) can be ensured. The volume ratio of any component other than the heat-resistant resin and the vibration-damping filler in the vibration-damping resin layer is not particularly limited, and can be selected according to the type.

[0073] The vibration-damping resin layer is not particularly limited as long as it can suppress the transmission of vibrations of a desired frequency, but it is preferable that it suppresses the transmission of vibrations of a frequency of, for example, 2 kHz. This is because noise can be particularly effectively suppressed. In order to adjust the vibration-damping resin layer to suppress the transmission of vibrations of a desired frequency, for example, the type and content of each component, such as the vibration-damping filler and heat-resistant resin, in the vibration-damping resin layer, and the thickness of the vibration-damping resin layer may be adjusted.

[0074] The method for forming the vibration-damping resin layer is not particularly limited, but examples thereof include the following methods. First, a solution is prepared by dissolving a predetermined amount of heat-resistant resin in an organic solvent. Next, a predetermined amount of vibration-damping filler is added to the solution, and any other components are added as necessary, and the mixture is kneaded to prepare a coating material. Next, the coating material is applied to the parts that constitute the vibration generation source or vibration transmission path in the members of the high-pressure pump (for example, the inner surface of the lifter guide, the outer surface of the lifter, the fastening surface and seat surface of the flange, etc.). Next, the coating material applied to the members is heated, dried, and cured. This forms a vibration-damping resin layer.

[0075] The organic solvent used in the above method is not particularly limited and is selected according to the type of heat-resistant resin. For example, when a polyamide-imide resin is used as the heat-resistant resin, examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), 1,3-dimethyl-2-imidazolidinone (DMI), γ-butyrolactone (GBL), etc. When an epoxy resin is used, examples of the organic solvent include methyl ethyl ketone (MEK), toluene, etc.

[0076] The kneading method for preparing the coating material may be, for example, a method of kneading for 1 hour using a kneader. The method for applying the coating material to the members of the high-pressure pump is not particularly limited, and a general application method may be used, such as spray coating, screen printing, dipping, etc. The heating conditions for drying and curing the coating material are not particularly limited, and may be, for example, heating at a temperature of 100°C or higher and 370°C or lower for 30 minutes or longer and 3 hours or shorter. EXAMPLES

[0077] Hereinafter, the high pressure pump according to the embodiment will be described in more detail with reference to examples, reference examples, and comparative examples.

[0078] 1. Preparation of test pieces and evaluation of the NV performance of the vibration-damping resin layer on the test pieces In Reference Examples 1 to 11, test pieces in which a vibration-damping resin layer was formed on a substrate were produced, and in Comparative Example 1, a test piece consisting of only the substrate was prepared, and the NV performance of the vibration-damping resin layer was evaluated in these test pieces.

[0079] [Reference example 1] First, a coating material to be used for forming the vibration-damping resin layer of the high-pressure pump was prepared. Specifically, polyamide-imide resin was prepared as a heat-resistant resin, and a solution was prepared by dissolving a predetermined amount in N-ethyl-2-pyrrolidone (NEP) (organic solvent). Next, a thermoplastic elastomer was prepared as a vibration-damping filler, and a predetermined amount was added to the solution, followed by kneading for 1 hour using a kneader. In this way, a coating material was prepared so that the volume ratio of the vibration-damping filler to the total volume of the heat-resistant resin and the vibration-damping filler in the vibration-damping resin layer was 50 volume %.

[0080] Next, a test piece was prepared in which a vibration-damping resin layer was formed on the surface of a block-shaped substrate. Specifically, a block-shaped substrate made of SUS440C was first prepared, and a predetermined amount of coating material was applied to the surface of the substrate by spray coating. Next, the coating material applied to the substrate was heated at 180°C for 90 minutes to volatilize the organic solvent and dry and harden the coating material. As a result, a vibration-damping resin layer with a thickness of 1 μm was formed on the surface of the substrate, and a test piece was prepared.

[0081] [Reference example 2] A test piece was prepared in the same manner as in Reference Example 1, except that the vibration-damping resin layer was formed to a thickness of 5 μm.

[0082] [Reference example 3] A test piece was prepared in the same manner as in Reference Example 1, except that the vibration-damping resin layer was formed to a thickness of 10 μm.

[0083] [Reference example 4] A test piece was prepared in the same manner as in Reference Example 1, except that the vibration-damping resin layer was formed to a thickness of 20 μm.

[0084] [Reference example 5] A test piece was prepared in the same manner as in Reference Example 1, except that the vibration-damping resin layer was formed to a thickness of 50 μm.

[0085] [Reference example 6] A test piece was prepared in the same manner as in Reference Example 1, except that the vibration-damping resin layer was formed to a thickness of 100 μm.

[0086] [Reference example 7] A test piece was prepared in the same manner as in Reference Example 1, except that the vibration-damping resin layer was formed to a thickness of 200 μm.

[0087] [Reference example 8] First, a coating material was prepared in the same manner as in Reference Example 1, except that a urethane resin was prepared as a vibration-damping filler and added in a predetermined amount to the solution.

[0088] Next, a test piece was prepared in the same manner as in Reference Example 1, except that a vibration-damping resin layer was formed to a thickness of 100 μm using the coating material prepared in this Reference Example.

[0089] [Reference example 9] First, a test piece was prepared in the same manner as in Reference Example 8, except that a vibration-damping resin layer was formed to a thickness of 200 μm.

[0090] [Reference example 10] First, a coating material was prepared in the same manner as in Reference Example 1, except that microcapsules were prepared as a vibration-damping filler and added in a predetermined amount to the dissolving liquid.

[0091] Next, a test piece was prepared in the same manner as in Reference Example 1, except that a vibration-damping resin layer was formed to a thickness of 100 μm using the coating material prepared in this Reference Example.

[0092] [Reference example 11] First, a test piece was prepared in the same manner as in Reference Example 10, except that a vibration-damping resin layer was formed to a thickness of 200 μm.

[0093] [Comparative Example 1] A block-shaped substrate similar to that of Reference Example 1 was prepared, and used as a test piece as is without forming a vibration-damping resin layer.

[0094] [Evaluation of NV performance of vibration-damping resin layer using a ball drop test] A ball drop test was performed on the test pieces obtained in Reference Examples 1 to 11 and Comparative Example 1 to evaluate the influence of the thickness of the vibration-damping resin layer on the NV performance. Fig. 8 is a cross-sectional view that shows a schematic diagram of a ball drop tester.

[0095] In the ball drop test, as shown in FIG. 8, the test pieces were placed on a steel plate on an acceleration pickup installed on the top of the base of the ball drop tester. When the test pieces of Reference Examples 1 to 11 were placed, the vibration-damping resin layer was made to abut against the steel plate. This is because the purpose of the ball drop test is to measure the degree to which noise is suppressed when an impact is applied to the vibration-damping resin layer placed in the gap between parts. In the ball drop tester, a φ6.3 mm SUJ2 steel ball is held by an electromagnet directly above the test piece. In the ball drop test, the height of the steel ball before it is dropped (the distance from the top surface of the test piece) is set to 500 mm, and the magnetic force of the ball drop tester is turned off to drop the steel ball and cause it to collide with the test piece. Then, the sound generated at the time of the collision was collected by a microphone installed directly above the test piece, and the overall sound pressure level was measured in the frequency band of 20 Hz to 10 kHz. The measurement results are shown in Table 1 below. FIG. 9 is a graph showing the sound pressure level of the sound generated when a steel ball impacted against the thickness of the damping resin layer in the test pieces of Reference Examples 1 to 11 and Comparative Example 1.

[0096] As shown in Table 1 and FIG. 9 below, the sound pressure level decreases with an increase in the thickness of the vibration-damping resin layer, so it is considered that the NV performance improves with an increase in the thickness of the vibration-damping resin layer. When comparing the test piece made of only the substrate of Comparative Example 1 with the test pieces of Reference Examples 1 to 7 having the same composition of the vibration-damping resin layer, the test piece with the vibration-damping resin layer thinner than 10 μm has a sound pressure level reduction effect compared to the test piece made of only the substrate, but the reduction effect is not significant. On the other hand, the test piece with the vibration-damping resin layer thicker than 10 μm has a sound pressure level reduction effect of 5 dB or more compared to the test piece made of only the substrate. Therefore, it is considered that the thickness of the vibration-damping resin layer is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more. Furthermore, as shown in Table 1 and FIG. 9 below, even if the type of vibration-damping filler in the vibration-damping resin layer is changed, the same tendency is observed.

[0097] [Table 1]

[0098] 2. Construction of high-pressure pump and evaluation of NV performance of high-pressure pump In Examples 1-1 to 3-7, high-pressure pumps attached to the engine head (cylinder head) of the engine were produced, and the NV performance of these high-pressure pumps was evaluated.

[0099] [Example 1-1] A high-pressure pump was produced in which a vibration-damping resin layer with a thickness of 100 μm was provided on the outer circumferential surface (1) of the lifter.

[0100] Specifically, first, a lifter (material: diffusion clad steel D2, which is classified as a type of stainless clad steel in JIS G3601:2012) having a bottomed cylindrical shape was prepared. Next, a predetermined amount of the coating material prepared in Reference Example 1 was applied to the outer circumferential surface of the lifter by spray coating. Next, the coating material applied to the lifter was heated at 180°C for 90 minutes to volatilize the organic solvent and dry and harden the coating material. As a result, a vibration-damping resin layer was formed on the outer circumferential surface of the lifter to a thickness of 100 μm.

[0101] Next, a semi-finished product was assembled from the lifter on which the vibration-damping resin layer was formed, the cylinder holding portion of the lower housing, the flange portion (material: SUS436 classified by JIS G4305), the engine fitting portion, and other parts including the cylinder, plunger, etc., before the installation of the high-pressure pump. Next, the semi-finished product was installed on an engine head on which the vibration-damping resin layer was not formed. At this time, the lifter, the engine fitting portion of the lower housing, the cylinder, the plunger, etc. were accommodated inside the accommodation hole of the engine head, and the flange portion of the lower housing was placed on the fastening surface of the engine head. The lower housing was fastened to the engine head by inserting bolts through the bolt insertion holes of the flange portion of the lower housing and the bolt insertion holes of the engine head. In this way, a high-pressure pump was manufactured. In this high-pressure pump, when the lifter reciprocates, the vibration-damping resin layer provided on the outer peripheral surface of the lifter comes into contact with and slides on the inner wall surface of the accommodation hole.

[0102] [Example 1-2] A high-pressure pump was fabricated in which a vibration-damping resin layer with a thickness of 100 μm was provided on the inner wall surface (the inner peripheral surface of the lifter guide) (2) of the accommodation hole of the engine head.

[0103] Specifically, first, a predetermined amount of the coating material prepared in Reference Example 1 was applied to the inner wall surface of the accommodation hole of the engine head by spray coating. Next, the coating material applied to the inner wall surface was heated at 180°C for 90 minutes to volatilize the organic solvent and dry and harden the coating material. As a result, a vibration-damping resin layer was formed on the inner wall surface of the accommodation hole of the engine head to a thickness of 100 μm.

[0104] Next, a semi-finished product before mounting a high-pressure pump was assembled in the same manner as in Example 1-1, except that a lifter before the formation of the vibration-damping resin layer was used. Next, the semi-finished product was attached to the engine head in the same manner as in Example 1-1, except that the semi-finished product was attached to the engine head on which the vibration-damping resin layer was formed. In this way, a high-pressure pump was produced. In this high-pressure pump, when the lifter reciprocates, the outer peripheral surface of the lifter comes into contact with and slides against the vibration-damping resin layer provided on the inner wall surface of the accommodation hole.

[0105] [Examples 1-3] A high-pressure pump was produced in which a 50 μm thick vibration-damping resin layer was provided on both the outer circumferential surface of the lifter (1) and the inner wall surface of the accommodation hole of the engine head (the inner circumferential surface of the lifter guide) (2).

[0106] Specifically, first, a vibration-damping resin layer was formed on the outer peripheral surface of the lifter in the same manner as in Example 1-1, except that the vibration-damping resin layer was formed to a thickness of 50 μm. Next, a vibration-damping resin layer was formed on the inner wall surface of the accommodation hole of the engine head in the same manner as in Example 1-2, except that the vibration-damping resin layer was formed to a thickness of 50 μm.

[0107] Next, a semi-finished product was assembled before mounting of a high-pressure pump in the same manner as in Example 1-1, except that the lifter on which the vibration-damping resin layer was formed was used. Next, the semi-finished product was attached to the engine head in the same manner as in Example 1-1, except that the semi-finished product was attached to the engine head on which the vibration-damping resin layer was formed. In this manner, a high-pressure pump was manufactured. In the high-pressure pump, when the lifter reciprocates, the vibration-damping resin layer provided on the outer peripheral surface of the lifter comes into contact with and slides against the vibration-damping resin layer provided on the inner wall surface of the accommodation hole.

[0108] [Examples 1-4] A high-pressure pump was produced in which a vibration-damping resin layer with a thickness of 200 μm was provided on the fastening surface (3) of the flange portion of the lower housing, which faces the engine head.

[0109] Specifically, a predetermined amount of the coating material prepared in Reference Example 1 was first applied to the fastening surface of the flange by spray coating. Next, the coating material applied to the flange was heated at 180°C for 90 minutes to volatilize the organic solvent and dry and harden the coating material. As a result, a vibration-damping resin layer was formed on the fastening surface of the flange to a thickness of 200 μm.

[0110] Next, a semi-finished product before mounting of a high-pressure pump was assembled in the same manner as in Example 1-1, except that a lifter before the formation of the vibration-damping resin layer was used and a lower housing having the flange portion on which the vibration-damping resin layer was formed was used. Next, the semi-finished product was attached to the engine head in the same manner as in Example 1-1, except that the semi-finished product was attached to the engine head. In this way, a high-pressure pump was produced. In the high-pressure pump, a vibration-damping resin layer was disposed between the fastening surface of the engine head and the fastening surface of the flange portion.

[0111] [Examples 1-5] A high-pressure pump was produced in which a vibration-damping resin layer with a thickness of 200 μm was provided on the seat surface (4) on the opposite side to the fastening surface of the flange portion of the lower housing.

[0112] Specifically, a predetermined amount of the coating material prepared in Reference Example 1 was first applied to the seating surface of the flange portion by spray coating. Next, the coating material applied to the flange portion was heated at 180°C for 90 minutes to volatilize the organic solvent and dry and harden the coating material. As a result, a vibration-damping resin layer was formed on the seating surface of the flange portion to a thickness of 200 μm.

[0113] Next, a semi-finished product before installation of a high-pressure pump was assembled in the same manner as in Example 1-1, except that a lifter before the formation of the vibration-damping resin layer was used and a lower housing having the flange portion on which the vibration-damping resin layer was formed was used. Next, the semi-finished product was attached to the engine head in the same manner as in Example 1-1, except that the semi-finished product was attached to the engine head. In this way, a high-pressure pump was produced. In the high-pressure pump, a vibration-damping resin layer was disposed between the seat surface of the flange portion and the head of the bolt.

[0114] [Examples 1-6] A high-pressure pump was produced in which a vibration-damping resin layer having a thickness of 200 μm was provided on both the fastening surface (3) facing the engine head in the flange portion of the lower housing and the seat surface (4) on the opposite side to the fastening surface.

[0115] Specifically, first, a vibration-damping resin layer was formed on the fastening surface of the flange portion in the same manner as in Example 1-4, except that the vibration-damping resin layer was formed to a thickness of 200 μm. Next, a vibration-damping resin layer was formed on the seating surface of the flange portion in the same manner as in Example 1-5, except that the vibration-damping resin layer was formed to a thickness of 200 μm.

[0116] Next, a semi-finished product was assembled before mounting of the high-pressure pump in the same manner as in Example 1-1, except that a lifter before the formation of the vibration-damping resin layer was used and a lower housing having the flange portion on which the vibration-damping resin layer was formed was used. Next, the semi-finished product was attached to the engine head in the same manner as in Example 1-1, except that the semi-finished product was attached to the engine head. In this manner, a high-pressure pump was produced.

[0117] [Examples 1-7] A high-pressure pump was produced in which a vibration-damping resin layer with a thickness of 100 μm was provided on the outer peripheral surface (1) of the lifter, and a vibration-damping resin layer with a thickness of 200 μm was provided on both the fastening surface (3) facing the engine head in the flange portion of the lower housing and the seat surface (4) opposite the fastening surface.

[0118] Specifically, first, a vibration-damping resin layer was formed on the outer peripheral surface of the lifter in the same manner as in Example 1-1. Next, a vibration-damping resin layer was formed on the fastening surface of the flange portion in the same manner as in Example 1-4, except that the vibration-damping resin layer was formed to a thickness of 200 μm. Next, a vibration-damping resin layer was formed on the seat surface of the flange portion in the same manner as in Example 1-5, except that the vibration-damping resin layer was formed to a thickness of 200 μm.

[0119] Next, a semi-finished product was assembled before mounting of the high-pressure pump in the same manner as in Example 1-1, except that a lower housing having the flange portion on which the vibration-damping resin layer was formed was used. Next, the semi-finished product was attached to the engine head in the same manner as in Example 1-1, except that the semi-finished product was attached to the engine head. In this manner, the high-pressure pump was manufactured.

[0120] [Example 2-1] A high-pressure pump was produced in which a vibration-damping resin layer having a thickness of 100 μm was provided on the outer peripheral surface of a lifter in the same manner as in Example 1-1, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 8 instead of the coating material prepared in Reference Example 1.

[0121] [Example 2-2] A high-pressure pump was produced in the same manner as in Example 1-2, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 8 instead of the coating material prepared in Reference Example 1, and the vibration-damping resin layer was provided on the inner wall surface of the accommodation hole of the engine head (the inner surface of the lifter guide).

[0122] [Example 2-3] A high-pressure pump was produced in which a vibration-damping resin layer having a thickness of 50 μm was provided on both the outer surface of the lifter and the inner wall surface of the accommodation hole of the engine head (the inner surface of the lifter guide), in the same manner as in Example 1-3, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 8 instead of the coating material prepared in Reference Example 1.

[0123] [Example 2-4] A high-pressure pump was produced in the same manner as in Example 1-4, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 8 instead of the coating material prepared in Reference Example 1, and the vibration-damping resin layer was provided on the fastening surface of the flange portion of the lower housing facing the engine head.

[0124] [Example 2-5] A high-pressure pump was produced in the same manner as in Example 1-5, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 8 instead of the coating material prepared in Reference Example 1, and a vibration-damping resin layer having a thickness of 200 μm was provided on the seating surface opposite the fastening surface of the flange portion of the lower housing.

[0125] [Example 2-6] A high-pressure pump was produced in the same manner as in Examples 1-6, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 8 instead of the coating material prepared in Reference Example 1, and in which a vibration-damping resin layer having a thickness of 200 μm was provided on both the fastening surface facing the engine head in the flange portion of the lower housing and the seating surface opposite the fastening surface.

[0126] [Example 2-7] A high-pressure pump was produced in the same manner as in Examples 1-7, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 8 instead of the coating material prepared in Reference Example 1, in which a vibration-damping resin layer with a thickness of 100 μm was provided on the outer peripheral surface of the lifter, and a vibration-damping resin layer with a thickness of 200 μm was provided on both the fastening surface facing the engine head in the flange portion of the lower housing and the seating surface opposite the fastening surface.

[0127] [Example 3-1] A high-pressure pump was produced in which a vibration-damping resin layer having a thickness of 100 μm was provided on the outer peripheral surface of a lifter in the same manner as in Example 1-1, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 10 instead of the coating material prepared in Reference Example 1.

[0128] [Example 3-2] A high-pressure pump was produced in the same manner as in Example 1-2, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 10 instead of the coating material prepared in Reference Example 1, and a vibration-damping resin layer having a thickness of 100 μm was provided on the inner wall surface of the accommodation hole of the engine head (the inner surface of the lifter guide).

[0129] [Example 3-3] A high-pressure pump was produced in which a vibration-damping resin layer having a thickness of 50 μm was provided on both the outer surface of the lifter and the inner wall surface of the accommodation hole of the engine head (the inner surface of the lifter guide), in the same manner as in Example 1-3, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 10 instead of the coating material prepared in Reference Example 1.

[0130] [Example 3-4] A high-pressure pump was produced in the same manner as in Example 1-4, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 10 instead of the coating material prepared in Reference Example 1, and the vibration-damping resin layer was provided on the fastening surface of the flange portion of the lower housing facing the engine head.

[0131] [Examples 3-5] A high-pressure pump was produced in the same manner as in Example 1-5, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 10 instead of the coating material prepared in Reference Example 1, and the vibration-damping resin layer was provided on the seating surface opposite the fastening surface of the flange portion of the lower housing.

[0132] [Examples 3-6] A high-pressure pump was produced in the same manner as in Example 1-6, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 10 instead of the coating material prepared in Reference Example 1, in which a vibration-damping resin layer having a thickness of 200 μm was provided on both the fastening surface facing the engine head in the flange portion of the lower housing and the seating surface opposite the fastening surface.

[0133] [Examples 3-7] A high-pressure pump was produced in the same manner as in Examples 1-7, except that the vibration-damping resin layer was formed using the coating material prepared in Reference Example 10 instead of the coating material prepared in Reference Example 1, in which a vibration-damping resin layer with a thickness of 100 μm was provided on the outer peripheral surface of the lifter, and a vibration-damping resin layer with a thickness of 200 μm was provided on both the fastening surface facing the engine head in the flange portion of the lower housing and the seating surface opposite the fastening surface.

[0134] [Comparative Example 2] A high-pressure pump was produced without a vibration-damping resin layer. Specifically, a semi-finished product was assembled before the installation of the high-pressure pump in the same manner as in Example 1-1, except that a lifter before the formation of the vibration-damping resin layer was used. Next, the semi-finished product was attached to the engine head in the same manner as in Example 1-1, except that the semi-finished product was attached to the engine head. In this manner, a high-pressure pump was produced.

[0135] [Evaluation of NV performance of high pressure pump] The NV performance of the high-pressure pumps produced in Examples 1-1 to 3-7 and Comparative Example 2 was evaluated.

[0136] Specifically, in an engine in which the high-pressure pumps of Examples 1-1 to 3-7 and Comparative Example 2 were attached to the engine head, acceleration pickups were attached to the upper surface of the high-pressure pump and near the high-pressure pump of the engine head. The engine was then driven to rotate at a constant rotation speed of 2000 rpm to operate the high-pressure pump. The acceleration pickup then measured the acceleration level of the overall value of vibration in the frequency band of 20 Hz to 20 kHz transmitted to the upper surface of the high-pressure pump and near the high-pressure pump of the engine head. The measurement results of the acceleration level of the vibration transmitted to the upper surface of the high-pressure pump are shown in Table 2 below. FIG. 10 is a graph showing the acceleration level of the vibration transmitted to the upper surface of the high-pressure pump in an engine in which the high-pressure pumps of Examples 1-1 to 3-7 in which the vibration-damping resin layer is formed at the positions (1) to (4), (3) + (4), and (1) + (3) + (4) are attached to the engine head. In Table 2 below and the graph of FIG. 10, the acceleration level of Comparative Example 2 is set as a reference value, and the acceleration levels of the Examples are shown as relative values ​​to the reference value.

[0137] As shown in Table 2 and FIG. 10 below, in the high pressure pumps of Examples 1-1 to 3-7, regardless of the location where the vibration-damping resin layer is provided, the acceleration level is significantly reduced by providing the vibration-damping resin layer compared to the reference value of Comparative Example 2 in which the vibration-damping resin layer is not provided. This is considered to be due to the vibration-damping effect of the vibration-damping resin layer. From the results shown in Table 2 and FIG. 10 below, even when the vibration-damping resin layer is provided on the fastening surface (3) or the seating surface (4) of the flange portion, the vibration-damping effect of the vibration-damping resin layer is recognized, but when the vibration-damping resin layer is provided on the outer peripheral surface (1) of the lifter or the inner wall surface (inner peripheral surface of the lifter guide) (2) of the accommodation hole of the engine head, the vibration-damping effect of the vibration-damping resin layer is recognized to be greater. This is considered to be because the generation of vibration itself can be suppressed at the vibration source. Also, when the vibration-damping resin layer is provided on both the fastening surface (3) and the seating surface (4) of the flange portion, the vibration-damping effect is recognized to be greater than when it is provided on one of them. It is found that when the vibration-damping resin layer is provided on the outer peripheral surface (1) of the lifter in addition to the fastening surface (3) and seat surface (4) of the flange portion, the vibration-damping effect becomes even greater.

[0138] From the above, from the viewpoint of being able to take measures against the vibration source, it is considered that the high-pressure pump is preferably provided with a vibration-damping resin layer provided on at least one of the inner circumferential surface of the lifter guide and the outer circumferential surface of the lifter. Furthermore, during the reciprocating movement of the lifter, the outer circumferential surface of the lifter always slides as a whole, whereas the sliding portion of the inner circumferential surface of the lifter guide changes according to the movement of the lifter. Therefore, the high-pressure pump provided with a vibration-damping resin layer provided on the inner circumferential surface of the lifter guide is more likely to maintain the performance of the vibration-damping resin layer as a result of suppressing wear of the vibration-damping resin layer compared to the high-pressure pump provided with a vibration-damping resin layer provided on the outer circumferential surface of the lifter. Therefore, it is considered that the high-pressure pump is preferably provided with a vibration-damping resin layer provided on the inner circumferential surface of the lifter guide.

[0139] [Table 2]

[0140] Although the embodiments of the high pressure pump of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as described in the claims. [Explanation of symbols]

[0141] 1 High pressure pump 9 Engine 18 Engine Head 180 Storage hole 181 Inner wall (lifter guide) 181s Inner wall 10 Main body 11 Lower housing 111 Cylinder holder 112 Flange part 113 Engine fitting 13 Cylinder 15 Upper housing 20 Lifter 20s outer surface 22 Lifter guide 24a First vibration-damping resin layer 24b Second vibration-damping resin layer 24c 3rd vibration-damping resin layer 24d 4th vibration-damping resin layer 30 Fuel supply section 50 Plunger part 51 Plunger 70 Fuel intake part 90 Fuel discharge relief section

Claims

1. A cylinder having a cylindrical hole; a plunger fitted in the cylindrical hole of the cylinder so as to be reciprocally slidable; a lifter that reciprocates in accordance with the rotation of the drive cam and reciprocates the plunger in conjunction with the lifter; A high-pressure pump including: a lifter guide that accommodates the lifter in an accommodation hole and guides the reciprocating movement of the lifter, The high-pressure pump further includes a vibration-damping resin layer provided on at least one of a vibration generating source and a vibration transmission path, The vibration-damping resin layer is provided on at least one of an inner peripheral surface of the lifter guide and an outer peripheral surface of the lifter, The high-pressure pump, wherein the vibration-damping resin layer contains a heat-resistant resin and a vibration-damping filler that converts vibration energy into thermal energy.

2. 2. The high pressure pump according to claim 1, wherein the vibration-damping resin layer is provided on an inner peripheral surface of the lifter guide.

3. a lower housing having a cylinder holding portion located radially outward of the cylinder and a flange portion protruding radially outward from the cylinder holding portion, the lower housing supporting the cylinder; 3. The high-pressure pump according to claim 1, further comprising a vibration-damping resin layer provided on at least one of a fastening surface of the flange portion facing the attached member and a seating surface opposite the fastening surface.

4. 4. The high pressure pump according to claim 1, wherein the vibration-damping resin layer has a thickness of 10 μm or more.

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