Solenoid valve mechanism and fuel pump

Abstract

The object of this invention is to suppress wear on a rod or rod-contacting components. The electromagnetic suction valve mechanism (electromagnetic valve mechanism) includes a suction valve (valve body), a rod engaging with the suction valve, and a magnetic attraction generating part that generates a magnetic attraction force that causes axial movement of the rod. A low-friction part is provided on the rod. The low-friction part is formed with a coefficient of friction such that the frictional force generated between the rod and the rod-contacting components is less than the rotational driving force of the rod.

Description

Technical Field

[0001] The present invention relates to a solenoid valve mechanism having a sliding component and a fuel pump including the solenoid valve mechanism. Background Technology

[0002] As a solenoid valve mechanism for a fuel pump, for example, it is described in Patent Document 1. The solenoid suction valve mechanism described in Patent Document 1 has a rod and an armature as movable parts, a rod guide as a fixed part, an outer core, a fixed core, a rod force-applying spring, and an armature force-applying spring.

[0003] The rod and armature, which are movable parts, are arranged as separate components. The rod is slidably held axially on the inner circumference of the rod guide. The inner circumference of the armature is slidably held on the outer circumference of the rod. The rod and armature can slide axially within a geometrically limited range.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2018 / 221077 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, in the electromagnetic suction valve mechanism described in Patent Document 1, there is a situation where the rod and armature, which are movable parts, are worn at the points of contact due to friction and collision forces generated at the points of contact.

[0009] The rod and armature can rotate about an axis extending in the sliding direction. However, the armature is sometimes affected by the magnetic attraction (magnetic attraction) generated between it and the fixed core, causing it to deflect in one radial direction and inhibiting rotation.

[0010] On the other hand, the rotation of the rod is inhibited due to sliding collisions with the armature. Therefore, the rod and armature repeatedly slide and collide in the same area, accelerating wear. Furthermore, the wear becomes biased towards one side due to the same area wearing down, impairing the function of both the rod and the armature.

[0011] The object of the present invention is to provide a solenoid valve mechanism and a fuel pump capable of suppressing wear of a rod or rod-contact components, in view of the above-mentioned problems.

[0012] Technical means for solving technical problems

[0013] To solve the aforementioned technical problems and achieve the objective of this invention, the solenoid valve mechanism of this invention includes a valve body, a rod engaging with the valve body, and a magnetic attraction generating part that generates a magnetic attraction force that causes the rod to move axially. At least one of the rod and a rod contact member that contacts the rod is provided with a low-friction part. The low-friction part is configured to have a coefficient of friction such that the frictional force generated between the rod and the rod contact member is less than the rotational driving force of the rod (i.e., the coefficient of friction of the low-friction part is set such that the frictional force generated between the rod and the rod contact member is less than the rotational driving force of the rod).

[0014] Furthermore, the fuel pump of the present invention includes: a main body having a pressurization chamber; a plunger supported by the main body in a reciprocating motion, which increases or decreases the capacity of the pressurization chamber by reciprocating motion; and the aforementioned solenoid valve mechanism for discharging fuel into the pressurization chamber.

[0015] The effects of the invention

[0016] The solenoid valve mechanism and fuel pump with the above structure can suppress wear of the rod or the parts in contact with the rod.

[0017] Furthermore, the technical problems, structures, and effects other than those described above will become clear from the following description of the implementation methods. Attached Figure Description

[0018] Figure 1 This is an overall structural diagram of a fuel supply system using the high-pressure fuel supply pump of the first embodiment of the present invention.

[0019] Figure 2 This is a longitudinal cross-sectional view (1) of the high-pressure fuel supply pump according to the first embodiment of the present invention.

[0020] Figure 3 This is a horizontal cross-sectional view of the high-pressure fuel supply pump according to the first embodiment of the present invention, viewed from above.

[0021] Figure 4 This is a longitudinal cross-sectional view (2) of the high-pressure fuel supply pump according to the first embodiment of the present invention.

[0022] Figure 5 This is an enlarged longitudinal cross-sectional view of the electromagnetic suction valve mechanism of the high-pressure fuel supply pump according to the first embodiment of the present invention.

[0023] Figure 6 This is a cross-sectional view of the rod in the electromagnetic suction valve mechanism of the high-pressure fuel supply pump according to the first embodiment of the present invention.

[0024] Figure 7 This is a side view of the rod in the electromagnetic suction valve mechanism of the high-pressure fuel supply pump according to the first embodiment of the present invention.

[0025] Figure 8This is an enlarged longitudinal cross-sectional view of the electromagnetic suction valve mechanism of the high-pressure fuel supply pump according to the second embodiment of the present invention.

[0026] Figure 9 This is an enlarged longitudinal cross-sectional view of the electromagnetic suction valve mechanism of the high-pressure fuel supply pump according to the third embodiment of the present invention. Detailed Implementation

[0027] 1. First Implementation Method

[0028] The solenoid valve mechanism and high-pressure fuel supply pump of the first embodiment of the present invention will be described below. Furthermore, common components in all figures are labeled with the same reference numerals.

[0029] [Fuel Supply System]

[0030] Next, use Figure 1 This describes a fuel supply system using the high-pressure fuel supply pump (fuel pump) of this embodiment.

[0031] Figure 1 This is an overall structural diagram of the fuel supply system using the high-pressure fuel supply pump of this embodiment.

[0032] like Figure 1 As shown, the fuel supply system includes a high-pressure fuel supply pump (fuel pump) 100, an ECU (Engine Control Unit) 101, a fuel tank 103, a common rail 106, and multiple injectors 107. The components of the high-pressure fuel supply pump 100 are integrally assembled on the pump body 1 (hereinafter referred to as "body 1").

[0033] Fuel in fuel tank 103 is drawn by feed pump 102 driven by a signal from ECU 101. The drawn fuel is pressurized to the appropriate pressure by a pressure regulator (not shown) and delivered to the low-pressure fuel inlet 51 of high-pressure fuel supply pump 100 via low-pressure piping 104.

[0034] A high-pressure fuel supply pump 100 pressurizes the fuel supplied from the fuel tank 103 and delivers it to the common rail 106. Multiple injectors 107 and a fuel pressure sensor 105 are installed on the common rail 106. The multiple injectors 107 are installed in a number corresponding to the number of cylinders (combustion chambers) and inject fuel according to the drive current output from the ECU 101. The fuel supply system of this embodiment is a so-called direct injection engine system in which the injectors 107 directly inject fuel into the cylinders of the engine.

[0035] The fuel pressure sensor 105 outputs the detected pressure data to the ECU 101. The ECU 101 calculates the appropriate amount of injected fuel (target injection length) and the appropriate fuel pressure (target fuel pressure) based on engine state quantities obtained from various sensors (such as crank angle, throttle opening, engine speed, fuel pressure, etc.).

[0036] Furthermore, the ECU 101 controls the driving of the high-pressure fuel supply pump 100 and the multiple injectors 107 based on calculations of fuel pressure (target fuel pressure), etc. That is, the ECU 101 has a pump control unit that controls the high-pressure fuel supply pump 100 and an injector control unit that controls the injectors 107.

[0037] The high-pressure fuel supply pump 100 has a pressure pulsation reduction mechanism 9, an electromagnetic suction valve mechanism (solenoid valve mechanism) 3 as a variable capacity mechanism, and an overflow valve mechanism 4 (see reference). Figure 2 ) and discharge valve mechanism 8. Fuel flowing in from low-pressure fuel inlet 51 passes through pressure pulsation reduction mechanism 9 and intake passage 10b to reach intake port 31b of electromagnetic intake valve mechanism 3.

[0038] Fuel flowing into the electromagnetic intake valve mechanism 3 passes through the intake valve 32, flows through the intake passage 1a formed in the main body 1, and then flows into the pressurization chamber 11. A plunger 2 is reciprocally inserted into the pressurization chamber 11. The plunger 2 is controlled by the engine cam 91 (see reference). Figure 2 It transmits power to perform reciprocating motion.

[0039] In the pressurization chamber 11, fuel is drawn in from the electromagnetic intake valve mechanism 3 during the downward stroke of the plunger 2, and pressurized during the upward stroke. When the fuel pressure in the pressurization chamber 11 exceeds a specified value, the discharge valve mechanism 8 opens, and the high-pressure fuel is pressurized and delivered to the common rail 106 through the fuel discharge port 12a. The discharge of fuel via the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic intake valve mechanism 3. Moreover, the opening and closing of the electromagnetic intake valve mechanism 3 is controlled by the ECU 101.

[0040] [High-pressure fuel supply pump]

[0041] Next, use Figures 2-4 Explain the structure of the high-pressure fuel supply pump 100.

[0042] Figure 2 This is a longitudinal section view (1) of the high-pressure fuel supply pump 100 when viewed from a section orthogonal to the horizontal direction. Figure 3 This is a horizontal cross-sectional view of the high-pressure fuel supply pump 100 when viewed from a section orthogonal to the vertical direction. Figure 4 This is a longitudinal section view (2) of the high-pressure fuel supply pump 100 when viewed from a section orthogonal to the horizontal direction.

[0043] like Figure 2 and Figure 3 As shown, the main body 1 of the high-pressure fuel supply pump 100 is provided with the aforementioned suction passage 1a and mounting flange 1b (see reference). Figure 3 The mounting flange 1b is tightly attached to the fuel pump mounting portion 90 of the engine (internal combustion engine) and is secured by a plurality of bolts (screws) not shown. That is, the high-pressure fuel supply pump 100 is secured to the fuel pump mounting portion 90 by the mounting flange 1b.

[0044] like Figure 2 and Figure 4 As shown, an O-ring 93, representing a specific example of a sealing component, is installed between the fuel pump mounting portion 90 and the main body 1. This O-ring 93 prevents engine oil from leaking to the outside of the engine (internal combustion engine) by passing between the fuel pump mounting portion 90 and the main body 1.

[0045] Furthermore, a reciprocating cylinder 6, which guides the plunger 2, is installed in the main body 1 of the high-pressure fuel supply pump 100. The cylinder 6 is cylindrical and is pressed into the main body 1 on its outer periphery. The main body 1 and cylinder 6, along with the electromagnetic intake valve mechanism 3, plunger 2, and discharge valve mechanism 8 (see reference...) Figure 3 Together they form a pressurized chamber 11.

[0046] In the main body 1, a fixing part 1c is provided that engages with the central portion of the cylinder 6 along its axial direction. The fixing part 1c of the main body 1 is obtained by being moved from below ( Figure 2 The cylinder 6 is plastically deformed by applying a load to the lower part of the body 1, pushing it upward. As a result, the cylinder 6 is pressed into the body 1. Consequently, the fuel pressurized in the pressurization chamber 11 does not leak between the cylinder 6 and the body 1.

[0047] A tappet 92 is provided at the lower end of the plunger 2. The tappet 92 converts the rotational motion of the cam 91 mounted on the engine camshaft into up-and-down motion, which is transmitted to the plunger 2. The plunger 2 applies force to the cam 91 side via the retainer 15 and the spring 16, pressing it against the tappet 92. The tappet 92 reciprocates along with the rotation of the cam 91. The plunger 2 and the tappet 92 reciprocate together, causing the volume of the pressure chamber 11 to change.

[0048] Furthermore, a sealing seat 17 is disposed between the cylinder 6 and the retainer 15. The sealing seat 17 is formed into a cylindrical shape for the insertion of the plunger 2, and has a secondary chamber 17a at its upper end located on the cylinder 6 side. In addition, the sealing seat 17 retains the plunger seal 18 at its lower end located on the retainer 15 side.

[0049] The plunger seal 18 slidably contacts the outer periphery of the plunger 2. During the reciprocating motion of the plunger 2, the plunger seal 18 seals the fuel in the auxiliary chamber 17a, preventing fuel from flowing into the engine interior. Furthermore, the plunger seal 18 prevents lubricating oil (including engine oil) used to lubricate the sliding parts within the engine from flowing into the interior of the main body 1.

[0050] exist Figure 2 In this configuration, the plunger 2 reciprocates in the vertical direction. When the plunger 2 descends, the volume of the pressurized chamber 11 expands; when the plunger 2 rises, the volume of the pressurized chamber 11 decreases. That is, the plunger 2 is configured to reciprocate in the direction that expands and contracts the volume of the pressurized chamber 11.

[0051] The plunger 2 has a large-diameter portion 2a and a small-diameter portion 2b. When the plunger 2 reciprocates, the large-diameter portion 2a and the small-diameter portion 2b are located in the auxiliary chamber 17a. Therefore, the volume of the auxiliary chamber 17a increases or decreases due to the reciprocating motion of the plunger 2.

[0052] Sub-chamber 17a is connected to fuel passage 10c (see reference). Figure 3 It is connected to the low-pressure fuel chamber 10. When the plunger 2 descends, a fuel flow is generated from the auxiliary chamber 17a to the low-pressure fuel chamber 10, and when the plunger 2 rises, a fuel flow is generated from the low-pressure fuel chamber 10 to the auxiliary chamber 17a. As a result, the fuel flow to and from the pump during the suction or return stroke of the high-pressure fuel supply pump 100 can be reduced, and the pressure pulsation generated inside the high-pressure fuel supply pump 100 can be reduced.

[0053] like Figure 3 and Figure 4 As shown, a suction connector 5 is installed on the side of the main body 1. The suction connector 5 is connected to a low-pressure pipe 104 (see reference 104) through which fuel supplied from the fuel tank 103 flows. Figure 1 Fuel in fuel tank 103 is supplied from suction connector 5 to the interior of high-pressure fuel supply pump 100.

[0054] The intake connector 5 has a low-pressure fuel intake port 51 connected to the low-pressure piping 104 and an intake flow path 52 communicating with the low-pressure fuel intake port 51. Fuel passing through the intake flow path 52 is then processed by the pressure pulsation reduction mechanism 9 provided in the low-pressure fuel chamber 10 and the intake passage 10b (see reference). Figure 2 The suction port 31b of the electromagnetic suction valve mechanism 3 (refer to...) Figure 2 ).like Figure 4 As shown, a suction filter 53 is installed in the fuel passage connected to the suction flow path 52. The suction filter 53 removes foreign matter present in the fuel, preventing foreign matter from entering the high-pressure fuel supply pump 100.

[0055] like Figure 2 and Figure 4As shown, a low-pressure fuel chamber (buffer chamber) 10 is provided in the main body 1 of the high-pressure fuel supply pump 100. The low-pressure fuel chamber 10 is covered by a buffer chamber cover 14. The buffer chamber cover 14 is, for example, formed as a cylindrical (cup-shaped) tube that is closed on one side.

[0056] like Figure 2 As shown, the low-pressure fuel chamber 10 has a low-pressure fuel flow path 10a and a suction passage 10b. The suction passage 10b is connected to the suction port 31b of the electromagnetic suction valve mechanism 3. Fuel passing through the low-pressure fuel flow path 10a reaches the suction port 31b of the electromagnetic suction valve mechanism 3 via the suction passage 10b.

[0057] A pressure pulsation reduction mechanism 9 is provided in the low-pressure fuel flow path 10a. When fuel flows into the pressurization chamber 11, it must again pass through the electromagnetic suction valve mechanism 3 (in the open state) into the suction passage 10b (see reference). Figure 2 Upon return, pressure pulsations are generated in the low-pressure fuel chamber 10. The pressure pulsation reduction mechanism 9 reduces the impact of the pressure pulsations generated in the high-pressure fuel supply pump 100 on the low-pressure piping 104.

[0058] The pressure pulsation reduction mechanism 9 is formed by bonding two corrugated disc-shaped metal plates together on their outer periphery and injecting an inert gas such as argon into the interior of the disc. The metal diaphragm damper of the pressure pulsation reduction mechanism 9 absorbs or reduces pressure pulsations by expanding / contracting.

[0059] like Figure 3 As shown, a discharge valve mechanism 8 communicating with the pressurization chamber 11 is provided in the main body 1. The discharge valve mechanism 8 includes a discharge valve seat component 81 and a discharge valve 82 that is in contact with and separate from the discharge valve seat component 81. In addition, the discharge valve mechanism 8 includes a discharge valve spring 83 that applies force to the discharge valve 82 towards the discharge valve seat component 81; and a discharge valve stop 84 that determines the stroke (travel distance) of the discharge valve 82. The discharge valve stop 84 is welded to the main body 1 at the abutment portion 85.

[0060] The discharge valve seat assembly 81, discharge valve 82, discharge valve spring 83, and discharge valve stop 84 are housed in a discharge valve chamber 1d formed in the main body 1. The discharge valve chamber 1d is a generally cylindrical space extending horizontally. One end of the discharge valve chamber 1d is connected to the pressurization chamber 11 via a fuel passage 1e. The other end of the discharge valve chamber 1d opens on the side of the main body 1. The opening at the other end of the discharge valve chamber 1d is closed by the discharge valve stop 84.

[0061] Furthermore, a discharge connector 12 is joined to the main body 1 via a welded portion 12b. The discharge connector 12 has a fuel discharge port 12a. The fuel discharge port 12a communicates with the discharge valve chamber 1d via a discharge passage 1f extending horizontally inside the main body 1. Additionally, the fuel discharge port 12a of the discharge connector 12 is connected to the common rail 106 (see reference). Figure 1 )connect.

[0062] When there is no fuel pressure difference between the pressurization chamber 11 and the discharge valve chamber 1d, the discharge valve 82 is pressed against the discharge valve seat component 81 by the force exerted by the discharge valve spring 83. Thus, the discharge valve mechanism 8 is in the closed state. When the fuel pressure in the pressurization chamber 11 is greater than the fuel pressure in the discharge valve chamber 1d, the discharge valve 82 moves against the force exerted by the discharge valve spring 83 and moves away from the discharge valve seat component 81. Thus, the discharge valve mechanism 8 is in the open state.

[0063] When the discharge valve mechanism 8 is in the open state, the high-pressure fuel in the pressurization chamber 11 is discharged to the common rail 106 (refer to) through the discharge valve chamber 1d, the discharge passage 1f, and the fuel discharge outlet 12a. Figure 1 When the discharge valve mechanism 8 is in the open state, the discharge valve 82 is in contact with the discharge valve stop 84, which limits the stroke of the discharge valve 82.

[0064] The stroke of the discharge valve 82 is appropriately determined by the discharge valve stop 84. This prevents a delay in closing the discharge valve mechanism 8 due to a long stroke of the discharge valve 82. As a result, fuel discharged into the discharge valve chamber 1d is prevented from flowing back into the pressurization chamber 11, and the efficiency of the high-pressure fuel supply pump 100 is suppressed. Thus, the discharge valve mechanism 8 acts as a check valve that restricts the direction of fuel flow.

[0065] In addition, an overflow valve mechanism 4 communicating with the pressurization chamber 11 is provided in the main body 1. The overflow valve mechanism 4 has an overflow valve spring 41, an overflow valve seat 42, an overflow valve 43, a seat component 44, and a spring support component 45.

[0066] The seat component 44 encloses the relief valve spring 41 to form a relief valve chamber. One end of the relief valve spring 41 abuts against the spring support component 45, and the other end abuts against the relief valve seat 42. The relief valve seat 42 engages with the relief valve 43. The force exerted by the relief valve spring 41 is applied to the relief valve 43 via the relief valve seat 42.

[0067] The relief valve 43 is pushed by the force applied by the relief valve spring 41, closing the fuel passage of the seat component 44. The fuel passage of the seat component 44 is connected to the discharge passage 1f (see reference). Figure 3 The flow of fuel between the pressurized chamber 11 (upstream side) and the seat component 44 (downstream side) is cut off by the overflow valve 43 contacting (pressurizing) the seat component 44.

[0068] When the pressure in the component upstream of the common rail 106 increases, the fuel on the seat component 44 pushes against the relief valve 43, resisting the force of the relief valve spring 41, causing the relief valve 43 to move. As a result, the relief valve 43 opens, and the fuel in the discharge passage 1f returns to the pressurization chamber 11 through the fuel passage of the seat component 44. Therefore, the pressure that causes the relief valve 43 to open is determined by the force of the relief valve spring 41.

[0069] In addition, the overflow valve mechanism 4 of this embodiment is connected to the pressurization chamber 11, but it is not limited to this. For example, it can also be connected to the low-pressure passage (low-pressure fuel inlet 51, intake passage 10b, etc.).

[0070] [Electromagnetic suction valve mechanism]

[0071] Next, refer to Figure 5 and Figure 6 Explanation of electromagnetic suction valve mechanism 3.

[0072] Figure 5 This is an enlarged longitudinal section view of the electromagnetic suction valve mechanism 3 of the high-pressure fuel supply pump 100, showing the open state of the electromagnetic suction valve mechanism 3. Figure 6 This is a cross-sectional view of the rod of the electromagnetic suction valve mechanism 3.

[0073] like Figure 5 As shown, the electromagnetic suction valve mechanism 3 is inserted into the transverse hole formed in the main body 1. The electromagnetic suction valve mechanism 3 includes: a suction valve seat 31 pressed into the transverse hole formed in the main body 1, a suction valve (valve body) 32, a rod 33, a rod force spring 34, an electromagnetic coil 35, and an armature 36.

[0074] The intake valve seat 31 is cylindrical, with a seating portion 31a on its inner periphery. Furthermore, an intake port 31b is formed on the intake valve seat 31, extending from the outer periphery to the inner periphery. This intake port 31b communicates with the intake passage 10b of the aforementioned low-pressure fuel chamber 10. Additionally, the intake valve seat 31 has a rod guide 31c through which a rod 33 passes.

[0075] A stop member 37 is disposed in the transverse hole formed in the main body 1, opposite to the seat portion 31a of the suction valve seat 31. The suction valve 32 is disposed between the stop member 37 and the seat portion 31a. Furthermore, a valve force spring 38 is installed between the stop member 37 and the suction valve 32. The valve force spring 38 applies force to the suction valve 32 towards the seat portion 31a.

[0076] The suction valve 32 closes the connection between the suction port 31b and the pressurization chamber 11 by abutting against the seating portion 31a. When the suction valve 32 closes the connection between the suction port 31b and the pressurization chamber 11, the electromagnetic suction valve mechanism 3 is in the closed state. The suction valve 32 opens the connection between the suction port 31b and the pressurization chamber 11 by abutting against the stop member 37. When the suction valve 32 opens the connection between the suction port 31b and the pressurization chamber 11, the electromagnetic suction valve mechanism 3 is in the open state.

[0077] Rod 33 passes through rod guide 31c and armature 36, which are drawn into valve seat 31. For example... Figure 6 As shown, a contact surface 331 that contacts the suction valve 32 is formed at one axial end of the rod 33. A flange 332 is formed at the other axial end of the rod 33. The flange 332 has: a first contact surface 332a facing the suction valve 32; and a second contact surface 332b located on the side opposite to the first contact surface 332a.

[0078] The second contact surface 332b of the flange 332 engages with one end of the rod-applying spring 34. The other end of the rod-applying spring 34 engages with the fixing core 39, which is configured to surround the rod-applying spring 34. The rod-applying spring 34 applies force to the suction valve 32 in the valve-opening direction toward the stop member 37 via the rod 33.

[0079] The armature 36 is formed in a generally cylindrical shape. At one axial end of the armature 36, a spring abutment portion 361 is formed, where one end of the armature force-applying spring 40 abuts. The other axial end of the armature 36 is opposite to the end face of the fixing core 39. At the other axial end of the armature 36, a flange abutment portion 362 is formed, where the first contact surface 332a of the flange 332 of the rod 33 abuts.

[0080] The other end of the armature force-applying spring 40 abuts against the rod guide 31c. The armature force-applying spring 40 applies force to the armature 36 towards the flange 332 side of the rod 33. The movable distance of the armature 36 is set to be longer than the movable distance of the suction valve 32. As a result, the suction valve 32 can reliably abut against (settle) the seat portion 31a, and the electromagnetic suction valve mechanism 3 can be reliably kept in the closed state.

[0081] The electromagnetic coil 35 is arranged so as to wrap around the fixed core 39 once. A terminal component 30 (see reference) is electrically connected to the electromagnetic coil 35. Figure 2 In the electromagnetic coil 35, current flows through the terminal component 30. When the electromagnetic coil 35 is de-energized and no current flows, the rod 33 is forced in the opening direction by the force of the rod force spring 34, pushing the suction valve 32 in the opening direction. As a result, the suction valve 32 moves away from the seat portion 31a and abuts against the stop member 37, and the electromagnetic suction valve mechanism 3 becomes open. That is, the electromagnetic suction valve mechanism 3 is a normally open type that opens when not energized.

[0082] In the open state of the electromagnetic suction valve mechanism 3, fuel from the suction port 31b passes between the suction valve 32 and the seat portion 31a, flows into the pressurization chamber 11 through multiple fuel passage holes (not shown) of the stop member 37 and the suction passage 1a. In the open state of the electromagnetic suction valve mechanism 3, the position of the suction valve 32 in the opening direction is restricted because it is in contact with the stop member 37. In the open state of the electromagnetic suction valve mechanism 3, the gap between the suction valve 32 and the seat portion 31a constitutes the movable range of the suction valve 32, which is called the opening stroke 32S.

[0083] When current flows through the electromagnetic coil 35, a magnetic attraction force is generated at the respective magnetic attraction surfaces S of the armature 36 and the fixed core 39. Therefore, the electromagnetic coil 35, the armature 36, and the fixed core 39 constitute the magnetic attraction force generating part of the present invention. When a magnetic attraction force is generated at the magnetic attraction surface S, the armature 36 is attracted by the fixed core 39. As a result, the armature 36 moves against the force applied by the lever spring 34 and comes into contact with the fixed core 39.

[0084] When the armature 36 moves toward the closing valve direction, which is the side of the fixed core 39, the lever 33 engaged by the armature 36 moves together with the armature 36. As a result, the force applied to the suction valve 32 in the opening valve direction is released, and it moves toward the closing valve direction due to the force applied by the valve force spring 38. When the suction valve 32 contacts the sitting portion 31a of the suction valve seat 31, the electromagnetic suction valve mechanism 3 enters the closed valve state.

[0085] [Operation of the high-pressure fuel supply pump]

[0086] Next, the operation of the high-pressure fuel supply pump in this embodiment will be explained.

[0087] exist Figure 2 When the cam 91 rotates and the plunger 2 descends, fuel flows from the intake passage 1a into the pressurization chamber 11 when the electromagnetic intake valve mechanism 3 opens. Hereinafter, the stroke of the plunger 2 descending will be referred to as the intake stroke. On the other hand, when the plunger 2 rises, the fuel in the pressurization chamber 11 is pressurized when the electromagnetic intake valve mechanism 3 closes, and the fuel flows through the discharge valve mechanism 8 (see reference 8). Figure 3 ) and was directed to common orbit 106 (refer to Figure 1 Pressurized conveying. Hereinafter, the process of piston 2 rising will be referred to as the compression stroke.

[0088] As described above, if the electromagnetic intake valve mechanism 3 closes during the compression stroke, the fuel flowing into the pressurization chamber 11 during the intake stroke is pressurized and discharged towards the common rail 106 side. On the other hand, if the electromagnetic intake valve mechanism 3 opens during the compression stroke, the fuel in the pressurization chamber 11 is pushed back to the intake passage 1a side and is not discharged towards the common rail 106 side. In this way, the discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic intake valve mechanism 3. Moreover, the opening and closing of the electromagnetic intake valve mechanism 3 is controlled by the ECU 101.

[0089] During the intake stroke, the volume of the pressurization chamber 11 increases, and the fuel pressure within the pressurization chamber 11 decreases. During this intake stroke, the fuel pressure in the pressurization chamber 11 is lower than the pressure at the intake port 31b. When the force applied based on the pressure difference exceeds the force applied by the valve force spring 38, the intake valve 32 disengages from the seat portion 31a, and the electromagnetic intake valve mechanism 3 becomes open. As a result, fuel passes between the intake valve 32 and the seat portion 31a, flowing into the pressurization chamber 11 through the multiple holes provided in the stop member 37.

[0090] After the intake stroke ends, the plunger 2 begins its upward motion, transitioning to the compression stroke. At this time, the electromagnetic coil 35 remains de-energized, and there is no magnetic attraction between the armature 36 and the fixed core 39. The lever spring 34 is configured to provide sufficient force to maintain the intake valve 32 in the open position away from the seat portion 31a when it is de-energized.

[0091] In this state, even if the plunger 2 moves upward, the rod 33 remains in the open position, and therefore the suction valve 32, which is force-applied through the rod 33, also remains in the open position. Thus, although the volume of the pressurization chamber 11 decreases with the upward movement of the plunger 2, in this state, the fuel that once flowed into the pressurization chamber 11 will return to the suction passage 10b through the open electromagnetic suction valve mechanism 3, and the pressure inside the pressurization chamber 11 will not rise. This stroke is called the return stroke.

[0092] During the return journey, from ECU101 (reference) Figure 1 When a control signal is applied to the electromagnetic intake valve mechanism 3, current flows through the terminal component 30 in the electromagnetic coil 35. When current flows in the electromagnetic coil 35, a magnetic attraction force acts on the magnetic attraction surface S of the fixed core 39 and the armature 36, attracting the armature 36 to the fixed core 39. When the magnetic attraction force becomes greater than the force applied by the lever spring 34, the armature 36 moves towards the fixed core 39 against the force of the lever spring 34, and the lever 33, which engages with the armature 36, moves away from the intake valve 32. As a result, due to the force applied by the valve spring 38 and the fluid force generated by the fuel flowing into the intake passage 10b, the intake valve 32 sits in the sitting part 31a, and the electromagnetic intake valve mechanism 3 becomes closed.

[0093] After the electromagnetic suction valve mechanism 3 is in the closed state, the fuel in the pressurization chamber 11 is pressurized as the plunger 2 rises, and then becomes the fuel discharge port 12a (refer to...). Figure 3 When the pressure exceeds the specified value, it is discharged through the discharge valve mechanism 8 to the common rail 106 (refer to...). Figure 1 The compression stroke between the bottom dead center and top dead center of the plunger 2 consists of the return stroke and the discharge stroke. The amount of fuel discharged can be controlled by controlling the energizing time of the solenoid coil 35 of the solenoid intake valve mechanism 3.

[0094] If the energizing time of the solenoid coil 35 is advanced, the proportion of the return stroke in the compression stroke becomes smaller, and the proportion of the discharge stroke becomes larger. As a result, less fuel returns to the intake passage 10b, and more fuel is discharged under high pressure. Conversely, if the energizing time of the solenoid coil 35 is delayed, the proportion of the return stroke in the compression stroke becomes larger, and the proportion of the discharge stroke becomes smaller. As a result, more fuel returns to the intake passage 10b, and less fuel is discharged under high pressure. Thus, by controlling the energizing time of the solenoid coil 35, the amount of fuel discharged under high pressure can be controlled to the amount required by the engine (internal combustion engine).

[0095] [Low friction section of the rod]

[0096] Next, refer to Figure 7 The description indicates that it is located at the low friction section of rod 33.

[0097] Figure 7 This is a side view of the rod in the electromagnetic suction valve mechanism 3.

[0098] like Figure 7 As shown, a low-friction portion 33a and a non-low-friction portion 33b are formed on the surface of the rod 33. The low-friction portion 33a and the non-low-friction portion 33b are adjacent to each other in the axial direction of the rod 33. The low-friction portion 33a is located in the area extending beyond the central portion from the other end of the rod 33 in the axial direction. The non-low-friction portion 33b includes one end of the rod 33 in the axial direction.

[0099] The low-friction portion 33a includes a first contact surface 332a and a second contact surface 332b of the flange 332. Thus, the low-friction portion 33a contacts the rod-applying spring 34 and the armature 36. Furthermore, the low-friction portion 33a includes a large portion of its area closer to the contact surface 331 than the flange 332. Thus, the low-friction portion 33a contacts the inner circumferential surface of the armature 36 and the rod guide 31c.

[0100] For example, when the axis of armature 36 is perfectly aligned with the axis of rod 33, there is a small gap between the inner circumferential surface of armature 36 and the outer circumferential surface of rod 33, so the inner circumferential surface of armature 36 does not contact the outer circumferential surface of rod 33. However, when the axis of armature 36 is not perfectly aligned with the axis of rod 33, rod 33 moves axially upward while contacting a portion of the inner circumferential surface of armature 36. That is, rod 33 slides on the inner circumferential surface of armature 36.

[0101] The armature 36 is affected by the magnetic attraction generated between it and the fixed core 39, and sometimes it deviates to the radial side and its rotation is inhibited. In this case, since the axis of the armature 36 is not completely aligned with the axis of the rod 33, the same portion of the inner circumferential surface of the armature 36 contacts the outer circumferential surface of the rod 33.

[0102] Furthermore, due to dimensional deviations in the rod guide 31c and the transverse hole in the main body 1 where the electromagnetic suction valve mechanism 3 is configured, there are cases where the axis of the rod guide 31c is not completely aligned with the axis of the rod 33. In this case, the same portion of the inner circumferential surface of the rod guide 31c contacts the outer circumferential surface of the rod 33.

[0103] On the other hand, due to contact and collision with other components, a driving force (hereinafter referred to as "rotational driving force") is generated in the rotational direction centered on the axis in rod 33. For example, rotational driving force is generated in rod 33 when the force applied by the rod force spring 34 is transmitted to rod 33. In addition, rotational driving force is generated in rod 33 when the contact surface 331 collides with the suction valve 32.

[0104] The low-friction part 33a is configured to have a coefficient of friction where the frictional force generated between the armature 36, the rod force-applying spring 34, and the rod guide 31c in contact with the rod 33 is lower than the rotational driving force of the rod 33. Methods for providing the low-friction part 33a include surface treatments such as plating, coating, and polishing. Furthermore, methods for coating include, for example, DLC (Diamond-Like Carbon) coating.

[0105] By providing the low-friction part 33a, the rotation of the rod 33 around its axis is not hindered. Therefore, the rod 33 rotates around its axis while moving axially. As a result, the rod 33 rarely comes into contact with the same parts of the rod-applying spring 34, the armature 36, and the rod guide 31c, thus dispersing wear on the rod 33, armature 36, etc., in the circumferential direction. This extends the lifespan of the rod 33 and the armature 36.

[0106] Because the armature 36 requires a material through which magnetic flux can pass, it is difficult to use materials that are not easily worn. Therefore, distributing the wear of the armature 36 in the circumferential direction greatly contributes to extending its lifespan.

[0107] Furthermore, there exists a situation where a portion of a component in contact that has been worn away embeds into a component of the other, thereby accelerating the development of wear. However, in this embodiment, by providing a low-friction portion 33a, the rod 33 can be prevented from slipping on the same portion of the rod force spring 34, armature 36, and rod guide 31c, thus suppressing partial wear.

[0108] Furthermore, the rod 33 has a non-low-friction portion 33b. This allows the non-low-friction portion 33b to be held in place using a fixing clamp during surface treatment. Providing a non-low-friction portion is effective when it is not possible to perform surface treatment on the entire surface of the rod 33. Alternatively, a low-friction portion, as described in this invention, can also be provided on the entire surface of the rod 33.

[0109] In this embodiment, the first contact surface 332a that contacts the flange abutment portion 362 of the armature 36 and the second contact surface 332b that contacts one end of the rod force-applying spring 34 are low-friction portions 33a. Furthermore, the outer peripheral surface of the flange 332 that contacts the armature 36 and the outer peripheral surface of the rod 33 that contacts the inner peripheral surface of the armature 36 and the rod guide 31c are also low-friction portions 33a.

[0110] However, as a low-friction part in this invention, it is sufficient to provide at least a portion of the part of the rod 33 that contacts other components. That is, as an electromagnetic suction valve mechanism in this invention, if a non-low-friction part is provided, a low-friction part may only be provided in the part where frictional force greater than the rotational pushing force of the rod is generated or easily generated.

[0111] Furthermore, as a low-friction part in this invention, it can also be provided in the rod contact member that the rod 33 contacts. That is, a low-friction part can also be provided in rod contact members such as the rod force spring 34, armature 36, armature force spring 40, and rod guide 31c. For example, when a low-friction part is provided in the armature force spring 40, the frictional force generated between the armature force spring 40 and the armature 36 is lower than the rotational pushing force of the armature 36. As a result, the armature 36 can be rotated without generating a magnetic attraction force. Furthermore, as a low-friction part in this invention, it can also be provided in both the rod and the rod contact member.

[0112] 2. Second Implementation Method

[0113] Next, refer to Figure 8 The electromagnetic suction valve mechanism of the second embodiment of the present invention will be described.

[0114] Figure 8 This is an enlarged longitudinal cross-sectional view of the electromagnetic suction valve mechanism of the second embodiment.

[0115] The high-pressure fuel supply pump of the second embodiment has the same structure as the high-pressure fuel supply pump 100 of the first embodiment. The difference between the high-pressure fuel supply pump of the second embodiment and the high-pressure fuel supply pump 100 of the first embodiment lies in the electromagnetic suction valve mechanism 3A. Therefore, the electromagnetic suction valve mechanism 3A will be described here, and the description of the structure common to the high-pressure fuel supply pump 100 will be omitted.

[0116] [Electromagnetic suction valve mechanism]

[0117] like Figure 8 As shown, the electromagnetic suction valve mechanism 3A is inserted into the transverse hole formed in the main body 1. The electromagnetic suction valve mechanism 3A has a suction valve seat 31, a suction valve 32, an armature rod 73, a rod force spring 34, and an electromagnetic coil 35, all of which are pressed into the transverse hole formed in the main body 1.

[0118] The armature rod 73 is formed of a material through which magnetic flux can pass. The armature rod 73 has: a rod body 731 that passes through a rod guide 31c of the intake valve seat 31; and an armature portion 732 integrally formed with the rod body 731. A contact surface 331 for contacting the intake valve 32 is formed at one axial end of the rod body 731. The armature portion 732 is continuous with the other axial end of the rod body 731.

[0119] The armature portion 732 is formed in a generally cylindrical shape. One axial end of the armature portion 732 is positioned opposite the rod guide 31c at a suitable distance. The other axial end of the armature portion 732 is opposite the end face of the fixing core 39. At the other axial end of the armature portion 732, a spring abutment portion 733 is formed, with one end of the rod force-applying spring 34 abutting against it. Furthermore, the armature portion 732 is movably disposed within the outer core 740, which engages with the main body 1.

[0120] A low-friction portion is formed in the spring abutment portion 733 of the armature rod 73. This low-friction portion has a coefficient of friction such that the frictional force generated between the armature rod 73 and the lever-applying spring 34 is lower than the rotational driving force of the armature rod 73. Therefore, the rotation of the armature rod 73 about its axis is not hindered. Thus, the armature rod 73 moves axially while rotating about its axis. As a result, the armature rod 73 is rarely in contact with the same portion of the lever-applying spring 34 and the outer core 740, and wear on the armature rod 73 is dispersed circumferentially. This extends the lifespan of the armature rod 73.

[0121] In this embodiment, a low-friction portion is provided only at the spring abutment portion 733 of the armature rod 73. However, low-friction portions may also be provided on the outer peripheral surface of the armature portion 732 and the outer peripheral surface of the rod body 731. Alternatively, low-friction portions may be provided on the entire surface of the armature rod 73.

[0122] 3. Third Implementation Method

[0123] Next, refer to Figure 9 The electromagnetic suction valve mechanism of the third embodiment of the present invention will be described.

[0124] Figure 9 This is an enlarged longitudinal cross-sectional view of the electromagnetic suction valve mechanism of the third embodiment.

[0125] The high-pressure fuel supply pump of the third embodiment has the same structure as the high-pressure fuel supply pump 100 of the first embodiment. The difference between the high-pressure fuel supply pump of the third embodiment and the high-pressure fuel supply pump 100 of the first embodiment lies in the electromagnetic suction valve mechanism 3B. Therefore, the electromagnetic suction valve mechanism 3B will be described here, and the description of the structure common to the high-pressure fuel supply pump 100 will be omitted.

[0126] [Electromagnetic suction valve mechanism]

[0127] like Figure 9 As shown, the electromagnetic suction valve mechanism 3B is inserted into the transverse hole formed in the main body 1. The electromagnetic suction valve mechanism 3B includes: a suction valve seat 31 pressed into the transverse hole formed in the main body 1, a suction valve 32, a rod 33, a rod force spring 34, an electromagnetic coil 35, an armature 36, and a spacer 750.

[0128] The spacer 750 is formed in an annular shape. The spacer 750 is disposed between one end of the rod-applying spring 34 and the second contact surface 332b of the rod 33. A low-friction portion is formed on the surface of the spacer 750 that contacts one end of the rod-applying spring 34. The coefficient of friction of the low-friction portion is set such that the frictional force generated between the spacer and the rod-applying spring 34 is lower than the rotational pushing force of the armature rod 73.

[0129] Therefore, the rotation of rod 33 around the axis is not hindered. Thus, rod 33 moves axially while rotating around the axis. As a result, rod 33 rarely comes into contact with the same parts of the rod-applying spring 34 and armature 36, and wear on rod 33 and armature 36 is dispersed circumferentially. This extends the lifespan of rod 33 and armature 36. Furthermore, since a low-friction part is provided in the spacer 750, which is a smaller component than rod 33 and rod-applying spring 34, the area requiring surface treatment can be reduced, leading to cost reduction.

[0130] Alternatively, a low-friction part can be provided on the surface of the spacer 750 that contacts the second contact surface 332b of the rod 33. Furthermore, a low-friction part can also be provided on both surfaces of the spacer 750 (the surface that contacts the second contact surface 332b and the surface that contacts the rod-applying spring 34).

[0131] 4. Summary

[0132] As described above, the electromagnetic suction valve mechanism 3 (electromagnetic valve mechanism) of the first embodiment includes a suction valve 32 (valve body), a rod 33 (rod) that engages with the suction valve 32, and a magnetic attraction generating part that generates a magnetic attraction force that causes the rod 33 to move axially. A low-friction part 33a (low-friction part) is provided on the rod 33. The low-friction part 33a is formed to have a coefficient of friction such that the frictional force generated between the rod 33 and the rod-applying spring 34 (rod contact member) is less than the rotational pushing force of the rod 33.

[0133] Therefore, the rotation of rod 33 around the axis is not hindered, and it moves axially while rotating around the axis. As a result, rod 33 is rarely in contact with the same parts of rod contact components such as rod-applying spring 34, and wear on rod 33 and rod contact components is distributed circumferentially. Thus, a longer lifespan for rod 33 and rod contact components can be achieved.

[0134] Furthermore, the electromagnetic attraction force generating part of the electromagnetic suction valve mechanism 3 (electromagnetic valve mechanism) of the first embodiment described above includes: an armature 36 (armature) that engages with the rod 33 (rod); a fixing core 39 (fixing core) opposite to the armature 36; and an electromagnetic coil 35 (coil) that generates a magnetic attraction force between the armature 36 and the fixing core 39. The rod contact member is the armature 36. Therefore, the rod 33 is prevented from frequently contacting the same part of the rod contact member such as the armature 36, and wear on the rod 33 and the armature 36 is dispersed circumferentially. As a result, a longer lifespan for the rod 33 and the armature 36 can be achieved.

[0135] Furthermore, the electromagnetic intake valve mechanism 3 (electromagnetic valve mechanism) of the first embodiment described above has a rod-applying spring 34 (rod-applying spring) that applies force to the rod 33 (rod) on the intake valve 32 (valve body) side. The rod contact member is the rod-applying spring 34. As a result, the rod 33 is not constantly in contact with the same part of the rod contact member such as the rod-applying spring 34, and the wear of the rod 33 and the rod contact member can be dispersed in the circumferential direction.

[0136] Furthermore, the electromagnetic suction valve mechanism 3 (electromagnetic valve mechanism) of the first embodiment described above has a rod guide 31c (rod guide) through which the rod 33 (rod) passes. The rod contact member is the rod guide 31c. As a result, the rod 33 is not constantly in contact with the same part of the rod contact member such as the rod guide 31c, and wear on the rod 33 and the rod contact member can be dispersed in the circumferential direction.

[0137] Furthermore, in the electromagnetic suction valve mechanism 3 (electromagnetic valve mechanism) of the first embodiment described above, a low-friction part 33a is provided on the rod 33. Moreover, the end of the rod 33 that contacts the suction valve 32 (valve body) is a non-low-friction part 33b. Therefore, when performing the work of setting the low-friction part 33a (during surface treatment), the non-low-friction part 33b can be held using a fixing clamp. As a result, the efficiency of setting the low-friction part 33a can be improved.

[0138] Furthermore, the electromagnetic attraction force generating part of the electromagnetic suction valve mechanism 3A (electromagnetic valve mechanism) of the second embodiment described above includes: an armature portion 732 (armature) integrally formed with the rod body 731 (rod); a fixing core 39 (fixing core) opposite to the armature portion 732; and an electromagnetic coil 35 (coil) that generates a magnetic attraction force between the armature portion 732 and the fixing core 39. In addition, the electromagnetic suction valve mechanism 3A includes a rod force spring 34 (rod force spring) that abuts against the armature portion 732 and applies force to the rod body 731 towards the suction valve 32 (valve body). Moreover, the rod contact member is the rod force spring 34. Therefore, the rod body 731 and the armature portion 732 are not constantly in contact with the same parts of the rod contact members such as the rod force spring 34, and wear on the rod contact members such as the rod body 731, the armature portion 732, and the rod force spring 34 can be dispersed in the circumferential direction.

[0139] Furthermore, the electromagnetic suction valve mechanism 3B (electromagnetic valve mechanism) of the third embodiment described above includes: a rod-applying spring 34 (rod-applying spring) that applies force to the rod 33 (rod) towards the suction valve 32 (valve body); and a spacer 750 (spacer) disposed between the rod 33 and the rod-applying spring 34. Moreover, the rod contact member is the spacer 750, and a low-friction portion is disposed in the spacer 750. This prevents the rod 33 from frequently contacting the same portion of the rod contact member, such as the rod-applying spring 34, thus dispersing wear on the rod 33 and the rod contact member circumferentially. Furthermore, since a low-friction portion is provided in the spacer 750, which is a smaller component than the rod 33 and the rod-applying spring 34, the area where the low-friction portion is provided can be reduced, thereby achieving cost reduction.

[0140] Furthermore, the low-friction portion in the above-described embodiment is formed by performing a plating or coating process. This allows for the easy provision of a low-friction portion.

[0141] Furthermore, the high-pressure fuel supply pump 100 (fuel pump) of the first embodiment described above includes: a main body 1 (main body) including a pressurization chamber 11 (pressurization chamber); and the aforementioned electromagnetic suction valve mechanism 3 (solenoid valve mechanism) for discharging fuel into the pressurization chamber 11. This ensures that the rod 33 does not frequently contact the same parts of rod contact components such as the rod force spring 34, and that wear on the rod 33 and rod contact components is dispersed circumferentially.

[0142] The embodiments of the solenoid valve mechanism and fuel pump of the present invention, including their effects, have been described above. However, the solenoid valve mechanism and fuel pump of the present invention are not limited to the above embodiments and can be implemented in various ways without departing from the spirit of the invention as described in the claims.

[0143] Furthermore, the above-described embodiments have been provided in detail to make the present invention easily understandable, and are not necessarily limited to including all the structures described. Moreover, a portion of the structure of one embodiment can be replaced with a structure of another embodiment; furthermore, a structure of another embodiment can be added to a structure of one embodiment. Furthermore, other structures can be added to, deleted from, or replaced in a portion of the structure of each embodiment.

[0144] For example, in the second embodiment described above, a low-friction portion is provided at the spring abutment portion 733 of the armature rod 73. However, as the solenoid valve mechanism of the present invention, the low-friction portion may not be provided at the spring abutment portion 733, and instead, the spacer 750 of the third embodiment may be provided between the spring abutment portion 733 and the rod-applying spring 34. In this case, the armature rod 73 may not frequently come into contact with the same portion of the rod-applying spring 34 and the outer core 740, and the wear of the armature rod 73 may be dispersed in the circumferential direction.

[0145] Explanation of reference numerals in the attached figures

[0146] 1: Main body, 2: Plunger, 3, 3A, 3B: Electromagnetic intake valve mechanism (solenoid valve mechanism), 4: Overflow valve mechanism, 5: Intake connector, 6: Cylinder, 8: Exhaust valve mechanism, 9: Pressure pulsation reduction mechanism, 10: Low-pressure fuel chamber, 11: Pressurization chamber, 12: Exhaust connector, 30: Terminal component, 31: Intake valve seat, 31a: Sealing part, 31b: Intake port, 31c: Rod guide, 32: Intake valve (valve body), 32S: Valve opening stroke, 33: Rod, 33a: Low friction part, 33b: Non-low friction part, 35: Electromagnetic coil, 36: Armature, 3 7: Stop, 39: Fixed core, 73: Armature rod, 91: Cam, 100: High-pressure fuel supply pump, 101: ECU, 102: Feed pump, 103: Fuel tank, 104: Low-pressure piping, 105: Fuel pressure sensor, 106: Common rail, 107: Injector, 331: Contact surface, 332: Flange, 332a: First contact surface, 332b: Second contact surface, 361: Spring abutment, 362: Flange abutment, 731: Rod body, 732: Armature part, 733: Spring abutment, 740: Outer core, 750: Spacer.

Claims

1. A solenoid valve mechanism comprising a valve body, a rod engaging with the valve body, and a magnetic attraction generating part for generating a magnetic attraction force that causes the rod to move axially, characterized in that: The rod is provided with a low-friction part and a non-low-friction part. The low-friction portion is configured to have a coefficient of friction such that the frictional force generated between the low-friction portion and the rod contact member that contacts the rod is less than the rotational thrust of the rod. The non-low friction portion includes the end of the rod that contacts the valve body.

2. The solenoid valve mechanism as described in claim 1, characterized in that: The magnetic attraction force generating part includes: an armature that engages with the rod; a fixed core opposite to the armature; and a coil that generates a magnetic attraction force between the armature and the fixed core. The rod contact component is the armature.

3. The solenoid valve mechanism as described in claim 1, characterized in that: A rod-applying spring that applies force to the rod on the valve body side. The rod contact component is the rod force-applying spring.

4. The solenoid valve mechanism as described in claim 1, characterized in that: It has a rod guide, the rod passing through the rod guide. The rod contact component is the rod guide.

5. The solenoid valve mechanism as described in claim 1, characterized in that: The magnetic attraction force generating part includes: an armature integrally formed with the rod; a fixed core opposite to the armature; and a coil that generates a magnetic attraction force between the armature and the fixed core. The solenoid valve mechanism has a rod-applying spring that abuts against the armature and applies force to the rod towards the valve body. The rod contact component is the rod force-applying spring.

6. The solenoid valve mechanism according to any one of claims 1 to 5, characterized in that: The low-friction part is formed by performing a plating or coating process.

7. A fuel pump, characterized in that, include: The main body has a pressurization chamber; A plunger, which is reciprocally supported by the main body, increases or decreases the capacity of the pressurization chamber through reciprocating motion; and The solenoid valve mechanism includes a valve body, a rod engaging with the valve body, and a magnetic attraction generating part that generates a magnetic attraction force causing axial movement of the rod. The solenoid valve mechanism can discharge fuel into the pressurization chamber. The rod is provided with a low-friction part and a non-low-friction part. The low-friction portion is configured to have a coefficient of friction such that the frictional force generated between the low-friction portion and the rod contact member that contacts the rod is less than the rotational thrust of the rod. The non-low friction portion includes the end of the rod that contacts the valve body.

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