JP2001020833A - High-pressure supply pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-pressure supply pump and its manufacturing method capable of reducing manufacturing cost as well as providing a plunger high in abrasion resistance and excellent in lubrication. SOLUTION: A plunger 60 comprises a taper part 64, a large diameter part 62, a small diameter part 63, and a head part 61, and is formed of, e.g. a stainless steel bar as base material for SUS 440C, and a plated layer comprising nickel, phosphorus, and polytetrafluoroethylene. The plated layer is formed on the exterior walls of the taper part 64 and the small diameter part 63. The exterior wall of the large diameter part 62 comprises an upper exterior wall 62a with the bare stainless steel bar, a middle exterior wall 62b formed with the plated layer, and a lower exterior wall 62c with the bare stainless steel bar. When the plunger 60 is positioned at a bottom dead center, a boundary 62d between the upper and middle exterior walls 62a, 62b is in a lower position of a figure by a lifted amount L of a pump cam from a boundary between an interior wall 77 and a taper wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure supply pump used for an internal combustion engine (hereinafter referred to as an "internal combustion engine"), and more particularly to a high-pressure supply pump suitable for a direct injection gasoline engine and a method of manufacturing the same.

[0002]

2. Description of the Related Art A high-pressure supply pump disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 9-112410 is known.
In this high-pressure supply pump, a plating layer containing polytetrafluoroethylene and having excellent lubricity is formed on the outer wall of the plunger. This plating layer contributes to enhancing the durability of the plunger by improving the lubricity between the outer wall of the plunger and the inner wall of the cylinder, and preventing an increase in noise. Generally, such a plating layer is inferior in wear resistance because it contains polytetrafluoroethylene.

[0003]

However, when fuel is supplied to the injector of a direct-injection gasoline engine using the above-described high-pressure supply pump, the wear resistance of the plating layer is inferior, so that the friction between the plating layer and the inner wall of the cylinder causes the plating layer to be inferior. And the clearance between the plunger and the inner wall of the cylinder is increased, thereby causing a problem that the discharge efficiency is reduced.

On the other hand, if a hard coating having excellent lubricity and excellent abrasion resistance is used in order to prevent such a decrease in discharge efficiency, a problem arises in that the manufacturing cost is increased.

The present invention has been made in order to solve such a problem, and has a high-pressure supply pump having a plunger having high abrasion resistance and excellent lubricity and capable of reducing the manufacturing cost, and a manufacturing method thereof. The aim is to provide a method.

[0006]

According to the high pressure supply pump of the present invention, a fuel intake passage, a fuel discharge passage, and a slide hole are formed in a cylinder, and an electromagnetic valve is provided in the intake passage. Have been. A fuel pressurizing chamber is defined by an outer wall near the end of the plunger on the suction passage side, an end face of the solenoid valve, and an inner wall of the cylinder. The plunger is provided with a tappet at an end opposite to the fuel pressurizing chamber, and the plunger reciprocates together with the tappet as the cam rotates. When the solenoid valve opens and the plunger moves to the opposite side of the solenoid valve, the fuel pressurizing chamber becomes negative pressure, and fuel is sucked from the suction passage into the fuel pressurizing chamber. When the solenoid valve closes and the plunger moves to the solenoid valve side, the fuel pressurized in the fuel pressurizing chamber is discharged from the discharge passage.

When the cam rotates and the plunger reciprocates, friction between the cam and the tappet exerts a force on the tappet and the plunger in a direction perpendicular to the axis of the plunger. For this reason, the plunger always reciprocates in the sliding hole while being inclined with the axis of the sliding hole. Therefore, it is a part of the plunger side wall that is in sliding contact with the cylinder inner wall. The drag is concentrated between the inner wall of the sliding hole and the side wall of the plunger in this portion, and the drag acting between the side wall of the plunger and the inner wall of the sliding hole that is in sliding contact with the inner wall of the sliding hole is particularly large. The side wall of the plunger that comes into sliding contact is particularly easily worn. On the other hand, the fuel leak pressure is high near the fuel pressurizing chamber in the minute gap between the inner wall of the sliding hole and the outer wall of the plunger. Therefore, in the vicinity of the fuel pressurizing chamber, even if the base material having low lubricity is exposed on the side surface of the plunger, seizure of the base material does not occur due to friction with the inner wall of the sliding hole.

Further, since a plating layer having higher lubricity than the base material is formed on the plunger side wall, seizure due to friction between the outer wall of the plunger and the inner wall of the sliding hole and generation of abnormal noise are prevented. Further, the plunger is exposed on the side wall near the fuel pressurizing chamber, which is in sliding contact with the inner wall of the sliding hole, because the base material having better wear resistance is exposed than the plating layer. Compared with a high-pressure supply pump provided with a plunger having a plating layer inferior to the base material in abrasion resistance, it is possible to suppress the abrasion of the plunger and prevent a decrease in discharge efficiency. On the other hand, since the fuel leak pressure is high near the fuel pressurizing chamber in the minute gap between the inner wall of the sliding hole and the outer wall of the plunger, friction between the substrate exposed on the outer wall of the plunger and the inner wall of the sliding hole causes the fuel to leak. No burn-in occurs. In addition, since it is possible to use a material having lower wear resistance than the base material for the plating layer, it is possible to reduce the manufacturing cost.

According to the high-pressure supply pump of the second aspect of the present invention, the cylinder has a large-diameter hole on the suction passage side of the slide hole, the diameter being larger than the slide hole and defining the fuel pressurizing chamber. Have. In the plunger, the base material is exposed on the side wall of a portion of the inner wall of the sliding hole that is in sliding contact with the edge on the large-diameter hole side. Since the side wall of the plunger slidingly in contact with the large-diameter hole side edge of the inner wall of the sliding hole enters and exits the large-diameter hole as the fuel pressurizing chamber, lubrication between the side wall of this portion and the inner wall of the sliding hole is particularly high. Therefore, by exposing the base material having better wear resistance than the plating layer to the entire portion of the side wall, it is possible to effectively prevent wear of the plunger side wall while preventing the base material from burning.

According to the high-pressure supply pump of the third aspect of the present invention, the base material of the plunger is exposed on the side wall of a portion of the inner wall of the sliding hole which is in sliding contact with the edge on the tappet side. The side wall of the plunger, which slides into the tappet-side edge of the inner wall of the sliding hole, enters and exits the space in which the oil used for lubricating the tappet and the cam is scattered. Has particularly high lubricity. Therefore, by exposing the base material having better wear resistance than the plating layer to the entire portion of the side wall, it is possible to effectively prevent wear of the plunger side wall while preventing the base material from burning.

According to the high-pressure supply pump according to the fourth aspect of the present invention, the plunger allows the fuel that leaks from the edge of the inner wall of the sliding hole on the tappet side into the minute gap between the inner wall of the sliding hole and the outer wall of the plunger. A concave portion for transferring to the pressure chamber side is formed on the outer wall. The lubricating property between the outer wall of the plunger and the inner wall of the sliding hole can be enhanced by the oil transferred by the concave portion even at a portion far from the end on the tappet side of the sliding hole. According to the high-pressure supply pump according to claim 5 of the present invention, the plating layer has excellent lubricity because it contains polytetrafluoroethylene.

According to a sixth aspect of the present invention, there is provided a method for manufacturing a high-pressure supply pump, comprising: forming a base having a large-diameter portion and a small-diameter portion; forming a plating layer on the substrate surface; Polishing to expose the large diameter portion of the base material, and leave the plating layer on the side wall of the small diameter portion of the base material. For this reason, it is easy to form a plunger by forming a plating layer on a portion where the outer diameter of the base material is small and exposing a portion where the outer diameter of the base material is large.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIG. 2 shows a first embodiment in which the high-pressure supply pump according to the present invention is applied to a gasoline engine of a direct fuel type.

The high-pressure supply pump 1 is configured such that an upper portion of a pump housing 40 containing an intake port having a suction passage (not shown), a solenoid valve 10, a delivery valve 20, a return valve 30, and a cylinder 70 is connected to an engine housing. It is exposed to the outside of the head cover (not shown) as a part and is fixed to the head cover. Other parts of the high-pressure supply pump 1 housed in the head cover are housed in the head cover surrounded by a cylindrical tappet guide 41. Tappet guide 41 is pump housing 4
0 and are formed integrally. In the present invention, the tappet guide 41 and the pump housing 40 may be formed separately. Further, the cylinder 70 and the pump housing 40 may be formed integrally. The pump cam 50 is attached to a valve cam shaft (not shown) that opens and closes an intake and exhaust valve (not shown), and reciprocates a plunger 60 described later.

Fuel is supplied from a low-pressure fuel pump (not shown) to the suction passage formed in the above-described suction port. The suction passage communicates with the fuel gallery 42 and also communicates with a sliding hole 74 described later through a return passage (not shown). The fuel gallery 42 is formed in an annular shape on the inner wall of the pump housing 40 around the solenoid valve 10, and communicates the above-described suction passage with the communication passage 11.

The solenoid valve 10 is inserted vertically into a receiving hole 43 formed in the pump housing 40. The solenoid valve 10 is attached to the pump housing 40 by being pressed by the pump housing 40 while the flange 13 is locked by the retaining nut 12. A control signal is supplied to the solenoid valve 10 via a connector 14.

The valve member 1 is attached to the valve body 15 of the solenoid valve 10.
A valve seat 17 on which the seat 6 can be seated and the communication passage 11 are formed. The valve member 16 is disposed on the valve body 15 so as to be able to be seated and unseated from the valve seat 17, and is urged in the valve opening direction by a compression coil spring 19. The plate 18 is sandwiched between the valve body 15 and the cylinder 70 in the axial direction. A suction passage 77 is formed in the plate 18. The valve body 15, the plate 18, and the cylinder 70 are in surface contact with each other in the axial direction, and even when the valve member 16 is separated from the valve seat 17, the fuel in the fuel pressurizing chamber, which will be described later, is retained by the fastening force of the retaining nut 12. The fuel gallery 42 is prevented from leaking.

The cylinder 70 is inserted into a cylinder hole 72 formed in the pump housing 40. As shown in FIG. 1, a large diameter hole 73 and a sliding hole 74 are formed in the cylinder 70. A fuel pressurizing chamber is defined by the inner wall 76 of the large diameter hole 73, the outer wall of the plunger 60, and the end face of the plate 18. A discharge passage 75 is formed in the inner wall 77 of the sliding hole 74, and the discharge passage 75 communicates with the discharge passage 24 formed in the pump housing 40. An annular fuel reservoir (not shown) is formed on the inner wall 76. The fuel reservoir communicates with the aforementioned intake passage via a return passage (not shown). Between the inner wall 77 and the inner wall 76, and the inner wall 77
Are formed on the side of the tappet 80, respectively.

The plunger 60 is reciprocally accommodated in a sliding hole 74 and is supported on an inner wall 77 so as to be slidable in the axial direction. The spring seat 81 is urged downward in FIG. 1 by a compression coil spring 82 and is in contact with the inner bottom surface of the tappet 80. Head part 61 of plunger 60
Is held between the inner bottom surface of the tappet 80 and the spring seat 81 and is urged downward by the spring seat 81 in FIG.

The plunger 60 includes a tapered portion 64, a large-diameter portion 62, a small-diameter portion 63, and a head portion 61. The plunger 60 is made of, for example, a stainless steel rod as a base material of SUS440C and nickel, phosphorus, and polytetrafluoroethylene. It is formed from a plating layer. A plating layer is formed on outer walls of the tapered portion 64 and the small diameter portion 63.

A minute gap is formed between the outer wall of the large diameter portion 62 and the inner wall 77 of the sliding hole. The outer wall of the large diameter portion 62 includes an upper outer wall 62a where the stainless steel bar is exposed, a central outer wall 62b where the plating layer is formed, and a lower outer wall 62c where the stainless steel bar is exposed. When the plunger 60 is at the bottom dead center position as shown in FIG. 1, a boundary 62d between the upper outer wall 62a and the central outer wall 62b is formed.
Is located in the lower part of FIG. 1 by the lift amount L of the pump cam 50 from the boundary between the inner wall 77 and the tapered wall 76b. In the present invention, a plating layer may be formed on the outer wall of the plunger 60 at a portion protruding from the sliding hole 74 to the large-diameter hole 73 at the position of the bottom dead center of the plunger 60. When the plunger 60 is at the bottom dead center position as shown in FIG.
The boundary 62e between b and the lower outer wall 62c is located at a position that matches the boundary between the inner wall 77 and the tapered wall 77a. In the present invention, a plating layer may be formed on the lower outer wall 62c.

The delivery valve 20 shown in FIG. 2 is screwed to the pump housing 40, and the valve member 21 is urged to the valve seat 23 by the compression coil spring 22. When the pressure in the large-diameter hole 73 is increased to a predetermined pressure or more, for example, 10 or more MPa by the reciprocating movement of the plunger 60, the valve member 21 is lifted against the urging force of the compression coil spring 22, and the discharge passage is opened. 24 and the discharge port 25 communicate with each other. The delivery valve 20 is connected to a common rail (not shown) by a fuel steel pipe (not shown). The tappet 80 is formed in a bottomed cylindrical shape, and the pump cam 50 is in contact with the bottom surface 80a. The tappet 80 is slidably supported on the inner wall of the tappet guide 41.

Here, a method of manufacturing the plunger 60 will be described. As shown in FIG. 3, a stainless steel rod 99 having a large diameter portion 99a and a small diameter portion 99b is formed. Here, the outer diameter D of the small diameter portion 99b is smaller than the final outer diameter F of the plunger after the matching grinding, and the large diameter portion 99a,
The outer diameter E of 99c is larger than the final outer diameter F of the plunger after matching grinding. Next, a plating layer 98 made of nickel, phosphorus, and polytetrafluoroethylene is formed on the entire surface of the stainless steel rod 99 as a base material. The side surface of the resultant 97 having the plating layer 98 formed on the entire surface is uniformly matched and ground, and the upper outer wall 62a and the lower outer wall 6a are ground.
The base material of the stainless steel bar is exposed at 2c. Regarding the operation of the high-pressure supply pump 1, (1) fuel intake stroke, (2)
The description will be made separately for the fuel pressurizing and feeding process.

(1) Fuel intake stroke When the plunger 60 is at the top dead center position, the plunger 6
The boundary between the upper outer wall 62a and the central outer wall 62b is located at the same position as the boundary between the inner wall 77 of the cylinder and the tapered wall 76a. The pump cam 50 rotates with the rotation of the valve cam shaft, and the plunger 60 reciprocates together with the tappet 80 and the spring seat 81. When the plunger 60 moves to the top dead center position shown in FIG.
The power supply to the solenoid 0 is cut off. Then, the valve member 16 is moved by the urging force of the compression coil spring 19 to the valve seat 17.
And the solenoid valve 10 is opened. Thereafter, when the plunger 60 moves downward in FIG. 1, the low-pressure fuel discharged from the low-pressure fuel pump passes through the suction passage, the fuel passage, the fuel gallery 42, and the communication passage 11 to form a large-diameter hole as a fuel pressurizing chamber. Inhaled to 73. And plunger 6
When 0 moves to the bottom dead center position, the maximum amount of low-pressure fuel flows into the large-diameter hole 73.

During the movement of the plunger 60 from the top dead center position to the bottom dead center position, the rotation of the pump cam 50 causes friction between the bottom surface 80a of the tappet and the pump cam 50, and the bottom surface 80a of the tappet The force acts in a direction perpendicular to the axis of the tappet 80. By the force and the urging force of the compression coil spring 82, the plunger 70 moves downward together with the tappet 80 as shown in FIG. During the stroke, the plunger moves downward as shown in FIG. 1 to generate a frictional force between the inner wall 77 of the sliding hole and the outer wall of the large diameter portion 62 of the plunger. This frictional force is generated because the axis of the plunger 70 is inclined from the axis of the sliding hole 74,
And the inner wall 77 of the sliding hole.

(2) Fuel pressurizing and feeding process When the plunger 60 is at the bottom dead center position, the plunger 6
The boundary between the lower outer wall 62c and the central outer wall 62b is located at the same position as the boundary between the inner wall 77 of the sliding hole and the tapered wall 77a. In a process in which the plunger 60 moves from the bottom dead center position to the top dead center position, when the plunger 60 reaches a position corresponding to a desired fuel discharge amount, energization of the solenoid of the solenoid valve 10 is turned on by the electronic control unit. You. As a result, the valve member 16 is sucked toward the valve seat 17 and sits on the valve seat 17. That is, the solenoid valve 10 is closed. Thereafter, when the plunger 60 further moves toward the top dead center position, the fuel in the large-diameter hole 73 as the fuel pressurizing chamber becomes high pressure, and the discharge passages 75 and 24, the gap between the valve seat 23 and the valve member 21, High-pressure fuel is discharged from the delivery valve 20 to a common rail (not shown) through the discharge port 25.

During the travel of the plunger 60 from the bottom dead center position to the top dead center position, the rotation of the pump cam 50 causes friction between the bottom face 80a of the tappet and the pump cam 50, and the bottom face 80a of the tappet The force acts in a direction perpendicular to the axis of the tappet 80. The plunger 70 moves upward together with the tappet 80 with the axis inclined from the axis of the slide hole 74 as shown in FIG. 1 by the force and the force that pushes the tappet up according to the cam profile. During the stroke, the plunger moves upward as shown in FIG. 1 to generate a frictional force between the inner wall 77 of the cylinder 70 and the outer wall of the large diameter portion 62 of the plunger. Since the axis of the plunger 70 is inclined from the axis of the sliding hole 74, the frictional force is largest between the upper outer wall 62a and the inner wall 77 of the sliding hole.

During the reciprocating movement of the plunger 60 as described above, the fuel flows into the large-diameter hole 73, so that the fuel in the minute gap between the upper outer wall 62a of the plunger 60 and the inner wall 77 of the sliding hole is formed. Leak pressure is high. The fuel leak pressure in the minute gap between the central outer wall 62b of the plunger 60 and the inner wall 77 of the sliding hole is lower than the fuel leak pressure. Further, during the reciprocating movement of the plunger 60, the oil of the pump cam chamber flows into the inside of the tappet 80, so that the oil leak in the minute gap between the lower outer wall 62c of the plunger 60 and the inner wall 77 of the sliding hole is formed. Pressure is high. The outer wall of the large diameter portion 62 of the plunger and the inner wall 77 of the sliding hole
The fuel and oil leaked into the minute gap between the fuel and the fuel accumulate in the fuel pool and return to the low-pressure suction passage through the return passage.

According to the high-pressure supply pump 1, the upper outer wall 62a and the lower outer wall 62c of the plunger are exposed because the stainless steel rods having better wear resistance than the plating layer are exposed on the upper outer wall 62a and the lower outer wall 62c. can do. Therefore, it is possible to prevent a decrease in the discharge efficiency due to wear of the outer wall of the plunger. Further, since the fuel leak pressure in the minute gap between the upper outer wall 62a and the inner wall 77 of the sliding hole is high, the upper outer wall 62a does not seize due to friction. Further, since the oil leak pressure in the minute gap between the lower outer wall 62c and the inner wall 77 of the sliding hole is high, the lower outer wall 62c is not seized by friction. Further, the central outer wall 62b of the plunger 60
Is formed with a plating layer containing polytetrafluoroethylene, so that the central outer wall 62b is not seized by friction.

(Second Embodiment) FIG. 4 shows a high-pressure supply pump according to a second embodiment of the present invention. Parts that are substantially the same as the high-pressure supply pump shown in the first embodiment are denoted by the same reference numerals. The plunger 90 includes a tapered portion 91 and a large-diameter portion 9.
2, a small-diameter portion 93 and a head portion 94, for example, a stainless steel rod as a base material of SUS440C and a plating layer made of nickel, phosphorus, and polytetrafluoroethylene. A plating layer is formed on outer walls of the tapered portion 91 and the small diameter portion 93.

A minute gap is formed between the outer wall of the large diameter portion 92 and the inner wall 77 of the sliding hole. The outer wall of the large diameter portion 92 includes an upper outer wall 90a where the stainless steel bar is exposed, and a lower outer wall 90b where the plating layer is formed. As shown in FIG. 4, when the plunger 60 is at the bottom dead center position, the boundary 90 between the upper outer wall 90a and the lower outer wall 90b.
1c is located below the boundary between the inner wall 77 and the tapered wall 76a by the lift amount of the pump cam 50 in FIG. In the present invention, a plating layer may be formed on the outer wall of the plunger 90 at a portion protruding from the small diameter portion to the large diameter hole 73 at the bottom dead center position of the plunger 90.

Leak grooves 95 and 96 are formed in the outer wall of the large diameter portion 92 of the plunger in the circumferential direction. Leak groove 95,
96 transfers oil leaking from the tappet side of the cylinder 70 to the minute gap between the outer wall of the large diameter portion 92 and the inner wall 77 of the sliding hole to the solenoid valve 10 side. In the present invention, the recess may be a single leak groove, a recess that does not penetrate the plunger, or a hole formed in the outer wall of the plunger.

According to the high-pressure supply pump 2, since the stainless steel rod which is superior in wear resistance to the plating layer is exposed on the upper outer wall 90a of the plunger 90, the upper outer wall 90a is exposed.
a can be prevented from being worn. Therefore, it is possible to prevent a decrease in the discharge efficiency due to wear of the outer wall of the plunger. Further, since the fuel leak pressure in the minute gap between the upper outer wall 90a and the inner wall 77 of the sliding hole is high, the upper outer wall 90a does not seize due to friction. Further, since a plating layer containing polytetrafluoroethylene is formed on the lower outer wall 90b of the plunger 90, the lower outer wall 90b is not seized by friction. Further, oil leaks into a minute gap between the lower outer wall 90b and the inner wall 77 of the sliding hole, and the oil is transferred to the solenoid valve 10, so that seizure due to friction of the lower outer wall 90b is effectively prevented. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a high-pressure supply pump according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a high-pressure supply pump according to a first embodiment of the present invention.

FIG. 3 is a plan view showing a base material of a plunger according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a high-pressure supply pump according to a second embodiment of the present invention.

[Explanation of symbols]

 1, 2 High pressure supply pump 10 Solenoid valve 50 Pump cam 60, 90 Plunger 70 Cylinder 73 Large diameter part 74 Sliding hole 75 Discharge passage 77 Suction passage 80 Tappet 95, 96 Leak groove (recess)

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tatsuo Sakai 1-1-1 Showa-cho, Kariya-shi, Aichi F-term in Denso Co., Ltd. (Reference) 3G066 AA02 AB02 AD12 BA49 BA61 CA01S CA03 CA04U CA08 CA09 CA21 CD03 CD06 CD07 CD21 CE03 CE05 CE22 3H075 AA03 BB03 BB13 BB21 CC15 CC19 CC32 DA04 DB04 DB23

Claims (6)

[Claims] 1. A cylinder having a fuel intake passage, a fuel discharge passage, and a sliding hole, and an electromagnetic valve provided in the intake passage for shutting off or circulating fuel sucked into the cylinder from the intake passage. A plunger housed in the sliding hole so as to be reciprocally movable, and a plating layer having a higher lubricity than the substrate is formed on the substrate, wherein the outer wall near the end on the suction passage side and the electromagnetic force A plunger having a fuel pressurized chamber defined by an end face of a valve and an inner wall of the cylinder, wherein the base material is exposed on a side wall near the fuel pressurized chamber that is in sliding contact with an inner wall of the sliding hole; A high-pressure supply pump, comprising: a tappet provided at an end opposite to the fuel pressurizing chamber; and a cam that contacts the tappet and reciprocates the plunger together with the tappet. 2. The cylinder has a large-diameter hole having a diameter larger than that of the slide hole and defining the fuel pressurizing chamber on the suction passage side of the slide hole. 2. The high-pressure supply pump according to claim 1, wherein the base material is exposed on a side wall of a portion of the inner wall of the sliding hole that is in sliding contact with an edge on the side of the large-diameter hole. 3. 3. The high-pressure supply pump according to claim 2, wherein the plunger has the base material exposed on a side wall of a portion of the inner wall of the sliding hole that is in sliding contact with the edge on the tappet side. 4. The plunger transfers oil leaking from an edge of the inner wall of the sliding hole on the tappet side to a minute gap between the inner wall of the sliding hole and the outer wall of the plunger to the fuel pressurizing chamber side. 4. The high-pressure supply pump according to claim 1, wherein a concave portion is formed on an outer wall. 5. The high-pressure supply pump according to claim 1, wherein the plating layer contains polytetrafluoroethylene. 6. The method for manufacturing a high-pressure supply pump according to claim 1, wherein a substrate having a large-diameter portion and a small-diameter portion is molded; Forming a plating layer on the substrate, polishing the plating layer to expose a large-diameter portion of the base material, and leaving a plating layer on a side wall of the small-diameter portion of the base material. How to make a high pressure supply pump.