JPWO2020080005A1 - High pressure fuel pump - Google Patents

Abstract

An object of the present invention is to provide a high-pressure fuel pump that solves any of the above-mentioned problems concerning the axial miniaturization of the seal structure and realizes the axial miniaturization of the seal structure. Therefore, the high-pressure fuel pump 100 seals between the plunger 2 that changes the volume of the pressurizing chamber, the outer peripheral side spaces 7s1, 7s2 formed on the outer peripheral side of the plunger 2 on the opposite side of the pressurizing chamber, and the outer space. The plunger seal 13 is provided with a metal member 16 having a seal facing surface 16b1 facing the end surface of the plunger seal 13 on the pressurizing chamber side and arranged on the outer peripheral side of the plunger 2. The seal facing surface 16b1 of the metal member 16 is radially outside the inner peripheral portion, and is opposite to the pressure chamber with respect to the outer peripheral side space 7s1 on the pressure chamber side with respect to the seal facing surface 16b1 and the seal facing surface 16b1. A through hole 16f that communicates with the outer peripheral side space 7s2 on the side is formed.

Description

The present invention relates to a high pressure fuel pump provided with a seal holding material.

As a background technique in the present technical field, for example, the high-pressure fuel pump described in Japanese Patent Application Laid-Open No. 2018-514702 (Patent Document 1) is known. The high-pressure fuel pump of Patent Document 1 is provided on the outer periphery of the piston and includes a sealing device (piston seal, low-pressure seal) that separates the space area on the fuel side and the space area on the oil side. The sealing device surrounds the lower portion of the piston (the portion facing the drive portion) in the radial direction, and the sealing device and the piston are configured to be relatively slidable. The seal device is arranged inside the pot-shaped seal support (hereinafter referred to as the first seal support) that supports one end (upper end) of the piston spring in the radial direction, and is located above the first seal support (of the seal device). It is supported in the axial direction by a hat-shaped holding member (hereinafter referred to as a second seal support) arranged on the entrance side in the insertion direction (see paragraphs 0023-0025 and FIG. 2 above). In this case, the inner diameter of the first seal support changes in the axial direction, a step portion is formed between the upper large diameter portion and the lower small diameter portion, and the sealing device has a lower small diameter portion. It is arranged so as to come into contact with the inner peripheral surface of the. On the other hand, the second seal support is arranged so as to come into contact with the inner peripheral surface of the upper large-diameter portion. Further, the second seal support is formed with a folded-back portion that folds upward at the lower end portion, and the folded-back portion faces the piston on the inner side in the radial direction (see FIG. 2).

Special Table 2018-514702

In the high-pressure fuel pump of Patent Document 1, a step portion is provided between the lower small diameter portion that the seal device contacts and the upper large diameter portion that the second seal support contacts, and this step portion is a shaft. Requires a finite length in the direction. Therefore, the stepped portion may be an obstacle (problem) to miniaturization in the axial direction in the seal structure.

Further, in the high-pressure fuel pump, since the piston slides with respect to the sealing device, frictional heat is generated in the sliding portion. This frictional heat can be cooled by circulating fuel in the sealing device. In the high-pressure fuel pump of Patent Document 1, the fuel circulates through the radially inner portion of the folded-back portion provided at the lower end portion of the second seal support. In this case, if the distance between the second seal support and the seal device in the axial direction is narrowed, the fuel circulation is hindered. Therefore, the fuel circulation structure configured in the second seal support may be an obstacle (problem) to the miniaturization in the axial direction in the seal structure.

In the above description, the names of the respective configurations and members are based on the names of Patent Document 1. Hereinafter, the piston is a plunger, the seal device (piston seal, low pressure seal) is a plunger seal (seal member), and the seal support (first seal support) is a seal holding member or a first seal support member, a holding member (second seal). The support) will be referred to as a metal member (second seal support member).

An object of the present invention is to provide a high-pressure fuel pump that solves any of the above-mentioned problems concerning the axial miniaturization of the seal structure and realizes the axial miniaturization of the seal structure.

In order to solve the above problems, the present invention is to form a through hole in a metal member facing the plunger seal so that fuel can be circulated in the space under the metal member. As a result, even if the metal member is placed close to the plunger seal, the fuel can be circulated in the space under the metal member. Alternatively, the seal holding member has a press-fit portion into which the metal member is press-fitted on the same surface as the inner peripheral surface of the seal holding member that holds the outer peripheral portion of the plunger seal. This eliminates the need to provide a throttle portion on the inner peripheral surface of the seal holding member between the contact portion of the plunger seal and the press-fit portion of the metal member.

According to the present invention, it is possible to provide a high-pressure fuel pump that realizes axial miniaturization in a seal structure. Other configurations, actions and effects of the present invention will be described in detail in the following examples.

It is an overall block diagram of the engine system to which the high pressure fuel pump which concerns on this invention is applied. It is sectional drawing which shows the vertical cross section (cross section parallel to the axial direction of a plunger) of the high pressure fuel pump which is presupposed to apply this invention. FIG. 5 is a cross-sectional view showing a horizontal cross section (a cross section orthogonal to the axial direction of the plunger) when the high-pressure fuel pump of FIG. 2 is viewed from above. FIG. 5 is a cross-sectional view showing a vertical cross section (cross section parallel to the axial direction of the plunger) when the high-pressure fuel pump of FIG. 2 is viewed from a direction different from that of FIG. It is sectional drawing which shows the vertical cross section (cross section parallel to the axial direction of a plunger) about 1st Example (Example 1) of the seal structure of this invention. FIG. 5 is an enlarged cross-sectional view showing the vicinity of the plunger seal, the first seal support member, and the metal member (second seal support member) of FIG. 5 in an enlarged manner. It is VII-VII sectional view which shows the inner part in the radial direction of the 2nd seal support member of FIG. It is a figure which shows the relationship between a plunger and a metal member (second seal support member) before (a), after (b), and (c) when a high pressure fuel pump is attached to an engine. Regarding the second embodiment (Example 2) of the seal structure of the present invention, the vicinity of the plunger seal, the first seal support member and the metal member (second seal support member) is enlarged and shown in an enlarged cross section similar to that of FIG. It is a figure. It is a perspective sectional view of the metal member (second seal support member) of the 2nd Example.

Hereinafter, examples according to the present invention will be described.

[Example 1]
FIG. 1 is an overall configuration diagram of an engine system to which the high-pressure fuel pump according to the present invention is applied. The portion surrounded by the broken line indicates the main body of the high-pressure fuel pump 100, and the mechanism and parts shown in the broken line indicate that the pump body 1 is integrally incorporated. Note that FIG. 1 is a drawing schematically showing the operation of the engine system, and the detailed configuration of the high-pressure fuel pump is different from the configuration of the high-pressure fuel pump of FIGS. 2 and later.

In the following description, the vertical direction may be specified, but the vertical direction is based on each figure and does not necessarily match the vertical direction when the high-pressure fuel pump 100 is mounted on the engine. Further, in the following description, the axial direction is defined by the central axis 2A (see FIG. 5) (longitudinal direction) of the plunger 2, and this axial direction is parallel to the central axis 2A of the plunger 2.

The fuel in the fuel tank 20 is pumped by the feed pump 21 based on a signal from the engine control unit 27 (hereinafter referred to as an ECU). This fuel is pressurized to an appropriate feed pressure and sent to the low pressure fuel suction port 10a of the high pressure fuel pump 100 through the suction pipe 28. As shown in FIGS. 3 and 4, the low-pressure fuel suction port 10a is composed of a suction joint 51.

The fuel that has passed through the low-pressure fuel suction port 10a reaches the suction port 31b of the solenoid valve mechanism 300 that constitutes the capacity variable mechanism via the damper chambers (10b, 10c) in which the pressure pulsation reduction mechanism 9 is arranged. Specifically, the solenoid valve mechanism 300 constitutes an electromagnetic suction valve mechanism.

The fuel that has flowed into the solenoid valve mechanism 300 passes through the suction port that is opened and closed by the suction valve 30 and flows into the pressurizing chamber 11. The engine cam mechanism 93 (see FIGS. 3 and 4) gives the plunger 2 reciprocating power. Due to the reciprocating motion of the plunger 2, fuel is sucked from the suction port opened and closed by the suction valve 30 in the descending stroke of the plunger 2, and the fuel in the pressurizing chamber 11 is pressurized in the ascending stroke. The pressurized fuel is pressure-fed to the common rail 23 on which the pressure sensor 26 is mounted via the discharge valve mechanism 8. Then, the injector 24 injects fuel into the engine based on the signal from the ECU 27. This embodiment is a high-pressure fuel pump applied to a so-called direct injection engine system in which the injector 24 injects fuel directly into the cylinder cylinder of the engine. In the high-pressure fuel pump 100, the solenoid valve mechanism 300 is controlled by a signal sent from the ECU 27 to the solenoid valve mechanism 300, and a desired fuel flow rate is discharged through the fuel discharge port 12.

FIG. 2 is a cross-sectional view showing a vertical cross section (a cross section parallel to the axial direction of the plunger) of a high-pressure fuel pump to which the present invention is applied. FIG. 3 is a cross-sectional view showing a horizontal cross section (a cross section orthogonal to the axial direction of the plunger) when the high-pressure fuel pump of FIG. 2 is viewed from above. FIG. 4 is a cross-sectional view showing a vertical cross section (cross section parallel to the axial direction of the plunger) when the high-pressure fuel pump of FIG. 2 is viewed from a direction different from that of FIG.

As shown in FIGS. 2 and 3, the high-pressure fuel pump 100 of this embodiment is closely fixed to the high-pressure fuel pump mounting portion 90 of the internal combustion engine. Specifically, as shown in FIG. 3, a screw hole 1b is formed in a mounting flange 1a provided on the pump body 1, and a plurality of bolts (not shown) are inserted into the screw hole 1b. As a result, the mounting flange 1a is brought into close contact with and fixed to the high-pressure fuel pump mounting portion 90 of the internal combustion engine. An O-ring 61 is fitted into the groove 1c of the pump body 1 for sealing between the high pressure fuel pump mounting portion 90 and the pump body 1 to prevent engine oil from leaking to the outside.

As shown in FIGS. 2 and 4, a cylinder 6 that guides the reciprocating motion of the plunger 2 and forms a pressurizing chamber 11 together with the pump body 1 is attached to the pump body 1. That is, the plunger 2 reciprocates inside the cylinder 6 to change the volume of the pressurizing chamber 11. Further, a solenoid valve mechanism 300 for supplying fuel to the pressurizing chamber 11 and a discharge valve mechanism 8 for discharging fuel from the pressurizing chamber 11 to the discharge passage are provided.

The cylinder 6 is press-fitted with the pump body 1 on the outer peripheral side thereof. An insertion hole for inserting the cylinder 6 from below is formed in the pump body 1, and an inner peripheral convex portion 1d deformed to the inner peripheral side so as to come into contact with the lower surface of the fixed portion 6a of the cylinder 6 at the lower end of the insertion hole. It is formed. The upper surface of the inner peripheral convex portion 1d of the pump body 1 presses the fixed portion 6a of the cylinder 6 upward in the drawing, and the cylinder 6 is sealed on the upper end surface so that the fuel pressurized in the pressurizing chamber 11 does not leak to the low pressure side. doing.

A tappet 92 is provided at the lower end of the plunger 2 to convert the rotational motion of the cam 93 attached to the camshaft of the internal combustion engine into a vertical motion and transmit it to the plunger 2. The plunger 2 is crimped to the tappet 92 by the plunger urging spring 4 via the retainer 15. As a result, the plunger 2 can be reciprocated up and down with the rotational movement of the cam 93.

The plunger seal 13 is held at the lower end of the inner circumference of the seal holding member 7, and is installed in a slidable contact with the outer periphery of the plunger 2 at the lower portion in the drawing of the cylinder 6. When the plunger 2 slides, the plunger seal 13 seals the fuel in the sub chamber 7s1 to prevent the fuel from flowing into the internal combustion engine. At the same time, the plunger seal 13 prevents the lubricating oil (including the engine oil) that lubricates the sliding portion in the internal combustion engine from flowing into the inside of the pump body 1.

A regulation member 16 for preventing the plunger 2 from falling when the high-pressure fuel pump 100 is not attached to the engine is attached to the upper portion of the plunger seal 13.

The seal holding member 7 is a member that supports the plunger seal 13 from the radial outer side and one end side (lower side) in the axial direction, and the regulating member 16 is a member that supports the plunger seal 13 from the other end side (upper side) in the axial direction. Is. Therefore, hereinafter, the seal holding member 7 will be referred to as a first seal support member, and the regulation member 16 will be referred to as a second seal support member. Since the second seal support member 16 is arranged inside the first seal support member 7, the first seal support member 7 may be referred to as an outer seal support member, and the second seal support member 16 may be referred to as an inner seal support member. be. Further, the second seal support member (regulatory member) 16 is a metal annular member, and may be referred to as a metal member or an annular member.

The regulating member 16 is made of a metal member, and is press-fitted inward in the radial direction of the first seal support member 7 to be fixed. When the high-pressure fuel pump is not attached to the engine, the plunger 2 moves downward due to gravity, but the plunger 2 is moved by the outer peripheral portion of the large diameter portion 2a of the plunger 2 coming into contact with the bottom surface of the regulating member 16. It is held by the pump body 1 without falling off from the pump body 1.

As shown in FIGS. 3 and 4, a suction joint 51 is attached to the side surface of the pump body 1 of the high-pressure fuel pump 100. The suction joint 51 is connected to a low-pressure pipe that supplies fuel from the fuel tank 20 to the high-pressure fuel pump 100, and the fuel is supplied from the suction joint 51 to the inside of the high-pressure fuel pump 100. The suction filter 52 prevents foreign matter existing between the fuel tank 20 and the low-pressure fuel suction port 10a from being absorbed inside the high-pressure fuel pump 100 by the flow of fuel.

The fuel that has passed through the low-pressure fuel suction port 10a goes to the pressure pulsation reduction mechanism 9 through the low-pressure fuel suction passage extending in the vertical direction in the pump body 1. The pressure pulsation reducing mechanism 9 is arranged in the damper chambers 10b and 10c between the damper cover 14 and the upper end surface of the pump body 1, and is supported from below by the holding member 9a arranged on the upper end surface of the pump body 1. Specifically, the pressure pulsation reduction mechanism 9 is a metal damper formed by superimposing two metal diaphragms. A gas of 0.3 MPa to 0.6 MPa is sealed inside the pressure pulsation reduction mechanism 9, and the outer peripheral edge portion is joined by welding.

Damper chambers 10b and 10c communicating with the low-pressure fuel suction port 10a and the low-pressure fuel suction passage are formed on the upper and lower surfaces of the pressure pulsation reduction mechanism 9. Although not shown in the figure, the holding member 9a is formed with a passage that communicates the upper side and the lower side of the pressure pulsation reducing mechanism 9.

The fuel that has passed through the damper chambers 10b and 10c then reaches the suction port 31b of the solenoid valve mechanism 300 via the low-pressure fuel suction passage 10d formed by extending in the vertical direction in the pump body 1. As shown in FIG. 3, the suction port 31b is formed on the suction valve seat member 31 forming the suction valve seat 31a in the vertical direction of FIG.

As shown in FIG. 2, the terminal 46a is molded integrally with the connector 46, and the unmolded end portion can be connected to the engine control unit 27 side.

The solenoid valve mechanism 300 will be described with reference to FIG.

When the plunger 2 moves in the direction of the cam 93 due to the rotation of the cam 93 and is in the suction stroke state, the volume of the pressurizing chamber 11 increases and the fuel pressure in the pressurizing chamber 11 decreases. When the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure of the suction port 31b in this stroke, the suction valve 30 is opened. When the suction valve 30 is in the maximum lift state, the suction valve 30 comes into contact with the stopper 32. When the suction valve 30 is lifted, the suction port between the suction valve seat 31a and the suction valve 30 is opened, and the solenoid valve mechanism 300 is opened. The fuel passes through the suction port between the suction valve seat 31a and the suction valve 30, and flows into the pressurizing chamber 11 through a hole (fuel passage) formed in the pump body 1 in the lateral direction.

After the plunger 2 finishes the inhalation stroke, the plunger 2 shifts to the ascending movement and shifts to the ascending stroke. Here, the electromagnetic coil 43 remains in a non-energized state and no magnetic urging force acts on it. The rod urging spring 40 is set to urge the rod convex portion 35a which is convex on the outer diameter side of the rod 35 and to have a necessary and sufficient urging force to keep the suction valve 30 open in a non-energized state. There is. The volume of the pressurizing chamber 11 decreases with the ascending movement of the plunger 2. In this state, the fuel once sucked into the pressurizing chamber 11 passes through the suction port of the suction valve 30 in the opened state again. Since it is returned to 10d, the pressure in the pressurizing chamber 11 does not rise. This process is called the return process.

In this state, when a control signal from the ECU 27 is applied to the solenoid valve mechanism 300, a current flows through the solenoid coil 43 via the terminal 46 (see FIG. 2). As a result, a magnetic attraction force acts between the magnetic core 39 and the anchor 36, and the magnetic core 39 and the anchor 36 come into contact with each other on the magnetic attraction surface. The magnetic attraction force overcomes the urging force of the rod urging spring 40 to urge the anchor 36, and the anchor 36 engages with the rod convex portion 35a to move the rod 35 away from the suction valve 30.

At this time, the suction valve 30 is closed by the urging force of the suction valve urging spring 33 and the fluid force caused by the fuel flowing into the suction passage 10d. After the valve is closed, the fuel pressure in the pressurizing chamber 11 rises with the ascending motion of the plunger 2, and when the pressure exceeds the pressure of the fuel discharge port 12, high-pressure fuel is discharged via the discharge valve mechanism 8, and the high-pressure fuel is a common rail. It is supplied to 23. This process is called a discharge process.

That is, the ascending stroke from the lower start point to the upper start point of the plunger 2 consists of a return stroke and a discharge stroke. Then, by controlling the energization timing of the solenoid valve mechanism 300 to the coil 43, the amount of high-pressure fuel discharged can be controlled.

The plunger 2 has a large diameter portion 2a and a small diameter portion 2b, and the volume of the sub chamber 7s1 is increased or decreased by the reciprocating motion of the plunger 2. The sub chamber 7s1 communicates with the damper chambers 10b and 10c by the fuel passage 10e. A fuel flow is generated from the sub chambers 7s1 to the damper chambers 10b and 10c when the plunger 2 is lowered, and from the damper chambers 10b and 10c to the sub chambers 7s1 when the plunger 2 is ascended.

As a result, the fuel flow rate inside and outside the pump in the suction stroke or the return stroke of the pump can be reduced, and the pressure pulsation generated inside the high-pressure fuel pump 100 can be reduced.

As shown in FIG. 3, the discharge valve mechanism 8 provided at the outlet of the pressurizing chamber 11 directs the discharge valve seat 8a, the discharge valve 8b that comes into contact with and separates from the discharge valve seat 8a, and the discharge valve 8b toward the discharge valve seat 8a. It is composed of a discharge valve spring 8c for urging and a discharge valve stopper 8d for determining a stroke (moving distance) of the discharge valve 8b. The discharge valve stopper 8d and the pump body 1 are joined by welding at the contact portion 8e to block the flow path through which fuel flows from the outside.

When there is no fuel differential pressure between the pressurizing chamber 11 and the discharge valve chamber 12a, the discharge valve 8b is crimped to the discharge valve seat 8a by the urging force of the discharge valve spring 8c, and is in a closed state. When the fuel pressure in the pressurizing chamber 11 becomes higher than the fuel pressure in the discharge valve chamber 12a, the discharge valve 8b opens against the discharge valve spring 8c. Then, the high-pressure fuel in the pressurizing chamber 11 is discharged to the common rail 23 through the discharge valve chamber 12a, the fuel discharge passage 12b, and the fuel discharge port 12. When the discharge valve 8b is opened, it comes into contact with the discharge valve stopper 8d and the stroke is limited. Therefore, the stroke of the discharge valve 8b is appropriately determined by the discharge valve stopper 8d. As a result, it is possible to prevent the fuel discharged at high pressure into the discharge valve chamber 12a from flowing back into the pressurizing chamber 11 due to the delay in closing the discharge valve 8b due to the stroke being too large, and the efficiency of the high pressure fuel pump 100 can be prevented. Can be suppressed from decreasing.

The fuel discharge port 12 is formed in the discharge joint 60, and the discharge joint 60 is welded and fixed to the pump body 1 by a welded portion 60a.

Next, the relief valve mechanism 200 will be described with reference to FIG.

The relief valve mechanism 200 includes a relief body 201, a relief valve 202, a relief valve holder 203, a relief spring 204, and a spring stopper 205. The relief body 201 is provided with a tapered seat portion. In the relief valve 202, the load of the relief spring 204 is applied via the relief valve holder 203, is pressed against the seat portion of the relief body 201, and shuts off the fuel in cooperation with the seat portion.

When the pressure of the fuel discharge port 12 becomes abnormally high due to a failure of the electromagnetic valve mechanism 300 of the high-pressure fuel pump 100 and becomes larger than the set pressure of the relief valve mechanism 200, the abnormally high-pressure fuel passes through the relief passage 213 to the low-pressure side. It is relieved in the damper room 10c. In this embodiment, the relief destination of the relief valve mechanism 200 is the damper chamber 10c, but the relief valve mechanism 200 may be configured to be relieved in the pressurizing chamber 11.

Next, the configuration (seal structure) around the seal portion (plunger seal) of this embodiment will be described with reference to FIGS. 5, 6 and 7.

FIG. 5 is a cross-sectional view showing a vertical cross section (cross section parallel to the axial direction of the plunger) with respect to the first embodiment (Example 1) of the seal structure of the present invention.

The seal structure SC of this embodiment is composed of a plunger seal 13, a first seal support member, and a regulation member (second seal support member).

The plunger seal 13 prevents the fuel inside the high-pressure fuel pump 100 from flowing into the engine, or prevents the oil inside the engine from flowing into the high-pressure fuel pump 100. The plunger seal 13 has a spring 13a1 whose upper portion extends in the radial direction and a spring 13a2 whose lower portion extends in the radial direction. As a result, the plunger seal 13 is held between the plunger seal 13 and the second seal support member 7 by the radial tension generated by the springs 13a1 and 13a2.

The plunger seal 13 has a recessed portion 13b1 recessed from the facing surface (upper surface) facing the sub chamber 7s1 to the side opposite to the sub chamber 7s1 side (lower side) over the entire circumference outward in the radial direction of the small diameter portion 2b. It is formed. A spring 13a1 is arranged in the recessed portion 13b1. Further, the plunger seal 13 has a recessed portion 13b2 recessed from this end surface to the sub chamber 7s1 side (upper side) on the end surface (lower surface) opposite to the facing surface (upper surface) facing the sub chamber 7s1, and has a small diameter portion 2b. It is formed on the outer side in the radial direction over the entire circumference. A spring 13a2 is arranged in the recessed portion 13b2.

The plunger seal 13 is arranged inside the first seal support member 7. In this case, the plunger seal 13 is arranged inside the first seal support member 7 in the radial direction and the axial direction. The first seal support member 7 has an inner peripheral side cylindrical portion 7a for accommodating the plunger seal 13. The inner peripheral side cylindrical portion 7a includes a large diameter portion 7a1 formed in the upper portion, a small diameter portion 7a2 formed in the lower portion, and a tapered portion 7a3 formed between the large diameter portion 7a1 and the small diameter portion 7a2. Have. An opening 7b is formed inward in the radial direction at the upper end of the large diameter portion 7a. Further, a flange portion 7c extending outward in the radial direction is formed at the upper end portion of the large diameter portion 7a, and an outer peripheral side cylindrical portion 7d is formed so as to be folded downward from the outer peripheral end portion of the flange portion 7c. NS.

The pump body 1 is formed with a recess 1e for assembling the first seal support member 7, and the lower end portion 7d1 of the outer peripheral side cylindrical portion 7d of the first seal support member 7 is inside the recess 1e of the first seal support member 7. It is press-fitted and fixed to the lower end portion 1e1 of the peripheral surface. Therefore, the upper end portion of the first seal support member 7 is inserted into the recess 1e.

The flange portion 7c constitutes a support portion (spring seat) that supports the upper end portion (end portion on the pressurizing chamber 11 side) of the plunger urging spring 4. Therefore, the plunger urging spring 4 is arranged between the inner cylindrical portion 7a and the outer peripheral side cylindrical portion 7d in the radial direction. The lower end of the plunger urging spring 4 is supported by the retainer 15, and the retainer 15 constitutes a spring seat at the lower end of the plunger urging spring 4.

The second seal support member 16 is arranged inside the first seal support member 7 and above the plunger seal 13 (on the opening 7b side). The plunger seal 13 is inserted into the inside of the first seal support member 7 through the opening 7b. A bottom portion 7e formed by being bent inward in the radial direction is provided at the lower end portion of the small diameter portion 7a2 of the first seal support member 7, and the plunger seal 13 is provided between the bottom portion 7e and the second seal support member 16. The axial position is constrained. Further, the position of the plunger seal 13 in the radial direction is restricted by the first seal support member 7 and the small diameter portion 2b of the plunger 2.

A through hole 7f penetrating in the axial direction is provided in the central portion of the bottom portion 7e of the first seal support member 7, and the lower end portion of the small diameter portion 2b of the plunger 2 is inserted through the through hole 7f to provide the first seal support member 7. It protrudes to the outside of 7.

The seal structure SC will be described in more detail with reference to FIG. FIG. 6 is an enlarged cross-sectional view showing the vicinity of the plunger seal, the first seal support member, and the metal member (second seal support member) of FIG. 5 in an enlarged manner. FIG. 6 shows the relationship between the plunger 2, the regulating member (second seal support member), and the plunger seal 13 after the high-pressure fuel pump 100 is attached to the engine, specializing in the seal structure SC.

The plunger seal 13 and the second seal support member 16 are provided inside the small diameter portion 7a2 of the inner peripheral side cylindrical portion 7a of the first seal support member 7. The plunger seal 13 is sandwiched between the lower inner peripheral surface 7a2-2 of the small diameter portion 7a2 and the outer peripheral surface of the small diameter portion 2b of the plunger 2 and is in contact with the lower inner peripheral surface 7a2-2. The second seal support member 16 is press-fitted and fixed to the upper portion 7a2-1 of the inner peripheral surface of the small diameter portion 7a2. That is, the first seal support member (seal holding member) 7 has a second seal on the same surface as the inner peripheral surface 7a2-2 of the first seal support member (seal holding member) 7 that holds the outer peripheral portion of the plunger seal 13. It has a press-fitting portion 7a2-1 into which the support member (metal member) 16 is press-fitted.

Here, the same surface is a cylindrical inner peripheral surface having the same inner diameter and continuous in the axial direction, or an axially continuous reduced diameter surface or expansion in which the inner diameter is reduced or expanded at a constant rate in the axial direction. It is a radial surface. In this case, the same surface does not mean that the portion where the plunger seal 13 contacts and the portion where the second seal support member 16 is press-fitted are at the same position in the axial direction, and the plunger seals that are separated from each other in the axial direction. It means that the contact portion of 13 and the press-fitting portion of the second seal support member 16 are present on one surface continuous in the axial direction.

The second seal support member 16 has an outer peripheral side cylindrical portion (press-fit cylindrical portion) 16a, a radial extension portion 16b, a folded portion (inner peripheral side cylindrical portion) 16c, and a diameter expansion portion (tapered portion) 16d. The outer peripheral side cylindrical portion 16a is press-fitted into the small diameter portion 7a2 of the first seal support member 7 and comes into contact with the inner peripheral surface upper portion 7a2-1. The radial extension portion 16b extends inward in the radial direction from the lower end portion of the outer peripheral side cylindrical portion 16a. The radial extension portion 16b is provided with a through hole 16f that penetrates in the axial direction. The folded-back portion 16c is formed so as to be folded back upward (on the opening 7b side of the first seal support member 7) from the inner peripheral end portion of the radially extending portion 16b. The diameter-expanded portion 16d is extended so as to expand in diameter upward from the upper end portion of the cylindrical portion 16a.

The second seal support member (metal member) 16 is arranged only on the radial inside and the axial inside of the first seal support member (seal holding member) 7. As a result, the amount of drawing when the first seal support member 7 and the second seal support member 16 are pressed can be suppressed, and stable strength can be obtained in the first seal support member 7 and the second seal support member 16.

The provision of the enlarged diameter portion 16d defines the axial position of the second seal support member 16 with respect to the first seal support member 7. That is, when the second seal support member 16 is press-fitted, the second seal support member 16 is inserted into the first seal support member 7 to a position where the enlarged diameter portion 16d and the tapered portion 7a3 of the first seal support member 7 interfere with each other. Then, the second seal support member 16 cannot be further inserted into the first seal support member 7 downward. As described above, the enlarged diameter portion 16d has a function for positioning the second seal support member 16 in the axial direction.

The plunger seal 13 is in contact with the lower inner peripheral surface 7a2-2 of the small diameter portion 7a2, but is not completely fixed to the lower inner peripheral surface 7a2-2. In this embodiment, the lower end of the plunger seal 13 abuts on the bottom portion 7e of the first seal support member 7, and the upper end abuts on the radial extension portion 16b of the second seal support member 16, so that the position in the axial direction is changed. It is fixed. When it is not necessary to completely fix the position of the plunger seal 13 in the axial direction, a gap may be provided between the radial extension portion 16b of the second seal support member 16 and the upper end portion of the plunger seal 13.

A frictional force is generated between the plunger seal 13 and the small diameter portion 2b of the plunger 2 due to the radial tension generated by the spring 13a1. When the engine is started and the high-pressure fuel pump 100 is in the driving state, the average pressure from the feed pump 21 is applied to the plunger seal 13, and the plunger seal 13 is pressed downward in FIG. In this case, even if a frictional force is generated between the plunger seal 13 and the small diameter portion 2b of the plunger 2, the plunger seal 13 is pressed against the bottom portion 7e of the first seal support member 7 by the average pressure of the feed pump 21. May be maintained.

In the above-described embodiment, the high-pressure fuel pump 100 includes a plunger 2 that changes the volume of the pressurizing chamber 11, and outer peripheral space 7s1, 7s2 formed on the outer peripheral side of the plunger 2 on the opposite side of the pressurizing chamber 11. A second seal support member having a plunger seal 13 for sealing between the outside space and a seal facing surface 16b1 facing the end surface of the plunger seal 13 on the pressure chamber 11 side, and arranged on the outer peripheral side of the plunger 2 ( A first seal support member (seal holding member) 7 that holds the plunger seal 13 and separates the outer peripheral side spaces 7s1 and 7s2 from the external space is provided. Further, the first seal support member (seal holding member) 7 is on the same surface as the inner peripheral surface of the first seal support member (seal holding member) 7 that holds the outer peripheral portion of the plunger seal 13, and the second seal support member (metal). Member) has a press-fitting portion into which the 16 is press-fitted.

In this embodiment, the press-fitting portion of the second seal supporting member 16 into the first seal supporting member 7 is on the same surface as the insertion portion of the plunger seal 13 into the first seal supporting member 7. As a result, on the surface where the second seal support member 16 faces the plunger seal 13, the gap formed between the first seal support member 7 and the second seal support member 16 is small, and the plunger seal 13 is in this gap. It can be prevented from entering.

In this case, it is desirable that the second seal support member (metal member) 16 is made of a metal having a thickness of 0.6 mm or less. The second seal support member 16 is formed with a corner portion bent at approximately 90 ° between the outer peripheral side cylindrical portion 16a and the radial extension portion 16b. When the radius of the corner portion becomes large, even when the outer peripheral side cylindrical portion 16a is press-fitted into the first seal support member 7, between the first seal support member 7 and the second seal support member 16 at this corner portion. There is a possibility that the plunger seal 13 may enter the gap. Therefore, by forming the second seal support member 16 with a metal having a thickness of 0.6 mm or less, the radius of the corner portion is reduced and the plunger seal 13 is prevented from entering the gap.

It is desirable that the first seal support member (seal holding member) 7 is made of a press-molded product. Further, it is desirable that the second seal support member (metal member) 16 is made of a press-molded product. As a result, the high-pressure fuel pump 100 can be mass-produced at low cost.

Since the press-fitting portion of the second seal support member 16 and the insertion portion of the plunger seal 13 are on the same surface of the first seal support member 7, the press-fitting portion of the second seal support member 16 and the insertion portion of the plunger seal 13 It is not necessary to provide a drawing portion between the two, and the drawing amount of press molding can be suppressed. As a result, stable strength can be obtained for the first seal support member 7. Further, since the amount of press molding is reduced, the material cost can be reduced. In addition, the distance between the fulcrum and the point of effort can be shortened, and the plunger can be held even with a thin wall.

In the above configuration, the upper part of the plunger seal 13 is exposed to fuel and the lower part (outside the pump) is exposed to oil. Since the plunger seal 13 is a resin material, changes in the fuel temperature and the oil temperature affect the decrease in the strength of the plunger seal 13. The temperature of the plunger seal 13 also rises due to the sliding heat generated by sliding the plunger 2 up and down.
Basically, the higher the temperature of the plunger seal 13, the lower the strength.

In order to cool the periphery of the plunger seal 13, it is effective to circulate the fuel having a lower temperature than the oil in the upper part (inside the pump) of the plunger seal 13 exposed to the fuel. For this purpose, it is necessary to provide a space for circulating fuel between the second seal support member 16 and the plunger seal 13. However, when the radial tension generated by the springs 13a1 and 13a2 between the plunger seal 13 and the first seal support member 7 is weaker than the tension force with the plunger 2, the plunger seal 13 moves up and down the plunger 2. At the same time, the movement between the second seal support member 16 and the first seal support member 7 is repeated, and the durability of the plunger seal 13 may decrease. Therefore, it is better to make the space (axial gap) formed between the second seal support member 16 and the plunger seal 13 as small as possible to suppress the movement of the plunger seal 13. Further, increasing the space (axial gap) formed between the second seal support member 16 and the plunger seal 13 causes an increase in the size of the seal structure SC in the axial direction, and thus this space (axial gap). ) Is desirable.

Therefore, it is desirable that the second seal support member 16 is press-fitted into the first seal support member 7 so as to come into contact with the plunger seal 13. In this case, the seal facing surface 16b1 of the second seal support member (metal member) 16 is configured to come into contact with the plunger seal 13.

As a result, even if the force of the plunger seal 13 with the plunger 2 exceeds the force of tension with the first seal support member 7, the metal member (second seal support member) 16 suppresses the movement of the plunger seal 13. can do.

However, if the seal facing surface 16b1 of the second seal support member 16 is brought into contact with the plunger seal 13 or the distance between the seal facing surface 16b1 and the plunger seal 13 is narrowed, fuel circulates in the space 7s2 on the plunger seal 13 side. There is a risk that it will not work.

Therefore, in the high-pressure fuel pump 100 of this embodiment, a through hole 16f is provided in the metal member (second seal support member) 16. Specifically, the high-pressure fuel pump 100 includes a plunger 2 that changes the volume of the pressurizing chamber 11, an outer peripheral side space 7s1, 7s2 formed on the outer peripheral side of the plunger 2 on the opposite side of the pressurizing chamber 11, and an external space. A plunger seal 13 for sealing between the plunger seal 13 and a metal member 16 having a seal facing surface 16b1 facing the end surface of the plunger seal 13 on the pressure chamber 11 side and arranged on the outer peripheral side of the plunger 2 are provided. Further, in the seal facing surface 16b1 of the metal member 16, the outer peripheral side space 7s1 on the pressurizing chamber 11 side with respect to the seal facing surface 16b1 and the pressurizing chamber with respect to the seal facing surface 16b1 are radially outside the inner peripheral portion. A through hole 16f that communicates with the outer peripheral side space 7s2 on the opposite side of 11 is formed.

More specifically, the second seal support member (metal member) 16 includes an outer peripheral side cylindrical portion 16a that is press-fitted into the inner peripheral portion of the first seal support member (seal holding member) 7 and an outer peripheral side cylindrical portion 16a. It is formed so as to fold back from the radial extension portion 16b extending inward in the radial direction from the end portion on the plunger seal 13 side and the inner peripheral end portion of the radial extension portion 16b to the opposite side to the plunger seal 13. It has an inner peripheral side cylindrical portion 16c. The through hole 16f is formed in the radial extension portion 16b. In this case, the inner peripheral side cylindrical portion 16c is bent so as to be folded back from the bottom portion 16b, the rigidity of the inner peripheral side cylindrical portion 16c can be easily increased, and the plate thickness constituting the second seal support member 16 is reduced. can do. Further, as described above, by reducing the plate thickness of the second seal support member 16, the radius of the corner portion between the outer peripheral side cylindrical portion 16a and the radial extension portion 16b can be reduced.

The above-mentioned through hole 16f can improve the circulation state of the fuel around the plunger seal 13, and the heat generated by the friction between the small diameter portion 2b of the plunger 2 and the plunger seal 13 is released to the outside of the seal structure SC by the circulating fuel. Can be done. In particular, the seal facing surface 16b1 of the second seal support member (metal member) 16 is provided with a through hole 16 radially outside the inner peripheral portion, so that the lower space 7s2 of the second seal support member 16 is provided. Efficiency phrase Fuel can be circulated, and the cooling effect of the plunger seal 13 is enhanced. As a result, the plunger seal 13 can be sufficiently cooled, so that a high-pressure fuel pump 100 that does not exceed the allowable temperature of the plunger seal 13 can be obtained.

Since the plunger seal 13 can be sufficiently cooled by providing the through hole 16f, the second seal support member 16 can be brought into contact with the plunger seal 13 or placed close to the plunger seal 13. As a result, the size of the seal structure SC in the axial direction can be reduced.

The arrangement of the through holes 16f will be described with reference to FIG. 7. FIG. 7 is a sectional view taken along line VII-VII showing a portion inside the second seal support member of FIG. 6 in the radial direction.

The through hole (communication passage) 16f is formed by opening a hole in the bottom portion 16b of the second seal support member 16. Further, when viewed from the direction of the plunger axis, it is desirable that the through hole 16f is formed directly above the recessed portion 13b1 of the plunger seal 13. The through hole 16f causes the fuel to move in the vertical direction. Therefore, by forming the communication passage 16f so as to overlap the recessed portion 13b1 of the plunger seal 13 when viewed from the axial direction, the upper space (sub chamber or outer peripheral side space) 7s1 and the lower space (outer peripheral side space) are formed. ) The amount of fuel that goes back and forth between 7s2 can be increased, and the cooling effect of the plunger seal 13 can be further improved.

As shown in FIG. 7, the bottom portion 16b of the second seal support member (metal member) 16 is provided with a plurality of through holes 16f and a plurality of cross-linking portions 16g. That is, in this embodiment, a plurality of through holes 16f formed in the seal facing surface 16b1 of the second seal support member (metal member) 16 are formed. As a result, the amount of fuel that travels between the upper space 7s1 and the lower space 7s2 can be increased, the fuel can be circulated uniformly in the circumferential direction, and the bias of the cooling effect in the circumferential direction can be suppressed. Can be done.

The through hole 16f and the crosslinked portion 16g are configured in the range of the bottom portion 16b forming an annular shape. That is, the through hole 16f and the crosslinked portion 16g are configured in the range from the inner peripheral radius r2 to the outer peripheral radius r1 as the center of the second seal support member 16. In this case, the total area of the through hole 16f is larger than the total area of the crosslinked portion 16g. That is, the second seal support member (metal member) 16 of the present embodiment has a plurality of through holes 16f at intervals in the circumferential direction, and between the two adjacent through holes 16f, the outer peripheral side cylindrical portion 16a and the inner circumference. It has a cross-linked portion 16g that connects to the side cylindrical portion 16c. The total area of the through holes 16f formed in the radial extension 16b is larger than the total area of the bridge 16g formed in the radial extension 16b. As a result, it becomes difficult to obstruct the flow of fuel flowing back and forth between the upper space 7s1 and the lower space 7s2, and the amount of fuel flowing through the through hole 16f can be increased. Therefore, it is possible to improve the cooling effect of the plunger seal 13.

The state before and after the high-pressure fuel pump 100 is attached to the engine will be described with reference to FIG. FIG. 8 is a diagram showing the relationship between the plunger and the metal member (second seal support member) before (a), after (b), and (c) when the high-pressure fuel pump is attached to the engine. Note that (b) indicates a state in which the plunger is at bottom dead center, and (c) indicates a state in which the plunger is at top dead center.

Before the high-pressure fuel pump 100 is attached to the engine head (FIG. 8A), the plunger 2 is pressed downward by the plunger urging spring 4. At that time, the step portion 2c between the large diameter portion 2a and the small diameter portion 2b of the plunger 2 may come into direct contact with the plunger seal 13 to damage the plunger seal 13. Therefore, a second seal support member (regulatory member) 16 is provided as a protective member for the plunger seal 13.

As a result, the stepped portion 2c of the plunger 2 comes into contact with the upper end portion of the inner peripheral side cylindrical portion 16c of the second seal support member 16 and is restricted from moving further downward. That is, in the high-pressure fuel pump of this embodiment, the plunger 2 has a large-diameter portion 2a, a small-diameter portion 2b, and a step portion 2c between the large-diameter portion 2a and the small-diameter portion 2b. The second seal support member (metal member) 16 has an inner peripheral side cylindrical portion 16c formed by bending toward the step portion 2c at a position overlapping with the step portion 2c in the radial direction.

In FIG. 8A, the distance δ1 between the stepped portion 2c of the plunger 2 and the upper end portion of the inner peripheral side cylindrical portion 16c is 0, and the lower end portion of the plunger 2 is located at Pa. At this time, the step portion 2c is not in contact with the plunger seal 13, and the plunger seal 13 can be protected.

As described above, the second seal support member 16 has a function as a regulating member for the axial movement of the plunger seal 13 and a function as a regulating member for the axial movement of the plunger 2.

Note that FIG. 8B shows a state in which the plunger 2 is at bottom dead center with the high-pressure fuel pump 100 attached to the engine head. Even in this state, the lower end portion of the plunger 2 is at a position Pb higher than the position Pa in FIG. 8A, and the distance δ2 between the step portion 2c of the plunger 2 and the upper end portion of the inner peripheral side cylindrical portion 16c is from 0. Also has a large value. Further, FIG. 8C shows a state in which the plunger 2 is at top dead center with the high-pressure fuel pump 100 attached to the engine head. In this state, the lower end portion of the plunger 2 is located at a position Pc higher than the position Pb in FIG. 8B, and the distance δ3 between the step portion 2c of the plunger 2 and the upper end portion of the inner peripheral side cylindrical portion 16c is δ2. Has a greater value than.

[Example 2]
The high-pressure fuel pump according to the second embodiment (Example 2) will be described with reference to FIGS. 9 and 10. FIG. 9 shows an enlarged view of the vicinity of the plunger seal, the first seal support member, and the metal member (second seal support member) with respect to the second embodiment (Example 2) of the seal structure of the present invention. It is a similar enlarged sectional view. FIG. 10 is a perspective sectional view of the metal member (second seal support member) of the second embodiment. Hereinafter, only the parts different from those of the first embodiment will be described. The same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

In this embodiment, a part of the configuration of the second seal support member 16 is changed from the first embodiment. Specifically, the second seal support member 16 is not provided with the folded-back portion (inner peripheral side cylindrical portion) 16c and the diameter-expanded portion 16d. In this embodiment, since the enlarged diameter portion 16d is not provided, the second seal support member (metal member) 16 is the first seal support member (seal holding member) 7 that holds the outer peripheral portion of the plunger seal 13. It is arranged only on the inner side in the radial direction with respect to the inner peripheral surface 7a2-2. As a result, the amount of drawing when the second seal support member 16 is pressed can be suppressed, and stable strength can be obtained in the second seal support member 16.

In this embodiment, the second seal support member 16 is arranged radially inside and only axially inside with respect to the small diameter portion 7a2 of the first seal support member 7. However, the upper end portion of the second seal support member 16 may protrude outward (upper side) in the axial direction from the upper end portion of the small diameter portion 7a2 of the first seal support member 7. However, the axial length of the second seal support member 16 is made shorter by arranging the second seal support member 16 only on the inner side in the axial direction with respect to the small diameter portion 7a2 of the first seal support member 7. This makes it possible to reduce the amount of drawing when the second seal support member 16 is pressed.

In this embodiment, the stepped portion 2c of the plunger 2 comes into contact with the bottom surface 16h of the second seal support member (regulatory member) 16, and the plunger 2 is restricted from moving further downward. As described above, due to the difference in the shape of the second seal support member 16, the portion of the second seal support member 16 with which the stepped portion 2c of the plunger 2 abuts is different. Other configurations are the same as those in the first embodiment, and the same effects as those in the first embodiment can be obtained for the same configurations as in the first embodiment. Although the portion (surface) 16h of the second seal support member 16 with which the stepped portion 2c of the plunger 2 abuts is different from that of the first embodiment, the effect of restricting the movement of the plunger 2 is the same as that of the first embodiment.

In this embodiment, the contact portion 16h of the second seal support member 16 with which the step portion 2c of the plunger 2 contacts is formed on a plane perpendicular to the axial direction of the plunger 2.

That is, in this embodiment, the plunger 2 has a large diameter portion 2a, a small diameter portion 2b, and a step portion 2c between the large diameter portion 2a and the small diameter portion 2b, and the second seal support member (metal member) 16 has a seal facing surface. It has a stepped portion facing surface 16h facing the stepped portion 2c on the opposite side of 16b1. By facing the stepped portion 2c, the stepped portion facing surface 16h regulates the movement of the plunger 2 to the opposite side to the pressurizing chamber 11 before mounting the high-pressure fuel pump 100.

According to this configuration, a sufficient contact surface between the stepped portion 2c of the second seal support member 16 and the contact portion (contact surface) 16h of the second seal support member 16 can be sufficiently secured on a flat surface. Therefore, the contact force is dispersed over a wide area, and the stress concentration can be relaxed, so that the reliability is improved. Further, when it is not necessary to bring the second seal support member 16 into contact with the plunger seal 13 in order to restrict the movement of the plunger seal 13, it is not necessary to provide the inner peripheral side cylindrical portion 16c of the first embodiment. 2 The axial dimension of the seal support member 16 can be reduced. Therefore, it is possible to more easily achieve both the protection function of the seal portion 13 of the high-pressure fuel pump 100 before the engine is mounted and the cooling function during driving.

It is desirable that the first seal support member (seal holding portion taste) 7 and the second seal support member (regulatory member) 16 are made of metal members and are manufactured by press molding. As a result, the high-pressure fuel pump 100 can be mass-produced at low cost.

The configuration of the first embodiment can be combined with the configuration of the present embodiment. For example, a configuration in which the stepped portion 2c of the plunger 2 is brought into contact with the bottom surface 16c of the second seal support member (regulatory member) 16 can be applied to the first embodiment, and the second seal support member 16 of the first embodiment can be used. The structure may be such that the inner peripheral side cylindrical portion 16c is eliminated. Alternatively, the enlarged diameter portion 16d of the second seal support member 16 in the first embodiment may be applied to the second seal support member 16 in the second embodiment.

Summarizing the examples described so far, the high-pressure fuel pump 100 according to the embodiment of the present invention has the following configuration.

The high-pressure fuel pump 100 is a first that supports the plunger 2 that changes the volume of the pressurizing chamber 11, the plunger seal 13 that is in sliding contact with the outer peripheral surface of the plunger 2, and the plunger seal 13 from the outside in the radial direction and one end side in the axial direction. A seal support member 7 and a second seal support member 16 that supports the plunger seal 13 from the other end side in the axial direction are provided. The first seal support member 7 is provided on one end side in the axial direction, and is provided at an insertion port 7b for inserting the plunger seal 13 and the second seal support member 16 inside the first seal support member 7, and on the other end side in the axial direction. A bottom portion 7e provided with a through hole 7f through which the plunger 2 is inserted, an inner peripheral surface 7a2-1, 7a2-2 having the same inner diameter formed in a predetermined range between the insertion port 7f and the bottom portion 7e, and the like. Has. The plunger seal 13 is sandwiched between the inner peripheral surfaces 7a2-1, 7a2-2 of the first seal support member 7 and the plunger 2 so as to be located on the bottom 7e side with respect to the second seal support member 16. The seal support member 16 is press-fitted into the inner peripheral surface 7a2-1 of the first seal support member 7 so as to be located on the insertion port 7b side with respect to the plunger seal 13.

The present invention is not limited to the above-described examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

2 ... Plunger, 2a ... Large diameter portion of plunger 2, 2b ... Small diameter portion of plunger 2, 2c ... Step portion of plunger 2, 7 ... First seal support member (seal holding member), 7a2-1 ... Second seal support The inner peripheral surface of the first seal support member 7 into which the member 16 is press-fitted, 7a2-2 ... The inner peripheral surface of the first seal support member 7 that holds the outer peripheral portion of the plunger seal 13, 7b ... The first seal support member 7. Constructed insertion port, 7e ... bottom of first seal support member 7, 7s1, 7s2 ... outer peripheral side space, 11 ... pressurizing chamber, 13 ... plunger seal, 16 ... second seal support member (metal member), 16a ... The outer peripheral side cylindrical portion of the second seal support member 16, 16b ... the radial extension portion of the second seal support member 16, 16b1 ... the seal facing surface of the second seal support member, 16c ... the inner circumference of the second seal support member 16. Side cylindrical portion, 16f ... Through hole, 16h ... Stepped portion facing surface facing the stepped portion 2c of the second seal support member 16, 16g ... Bridge portion connecting the outer peripheral side cylindrical portion 16a and the inner peripheral side cylindrical portion 16c, 100 ... High pressure fuel pump.

Claims (14)

A plunger that changes the volume of the pressurizing chamber and
A plunger seal that seals between the outer peripheral space and the outer space formed on the outer peripheral side of the plunger on the opposite side of the pressurizing chamber,
A metal member having a seal facing surface facing the end surface of the plunger seal on the pressurizing chamber side in the axial direction and arranged on the outer peripheral side of the plunger.
On the seal facing surface of the metal member, the outer peripheral side space on the pressurizing chamber side with respect to the seal facing surface and the pressurizing chamber with respect to the seal facing surface are radially outside the inner peripheral portion. A high-pressure fuel pump in which a through hole is formed that communicates with the outer peripheral space on the opposite side. A plunger that changes the volume of the pressurizing chamber and
A plunger seal that seals between the outer peripheral space and the outer space formed on the outer peripheral side of the plunger on the opposite side of the pressurizing chamber,
A metal member having a seal facing surface facing the end surface of the plunger seal on the pressurizing chamber side and arranged on the outer peripheral side of the plunger.
A seal holding member that holds the plunger seal and separates the outer peripheral space from the external space is provided.
The seal holding member is a high-pressure fuel pump having a press-fitting portion into which the metal member is press-fitted on the same surface as the inner peripheral surface of the seal holding member that holds the outer peripheral portion of the plunger seal. In the high-pressure fuel pump according to claim 1 or 2.
The plunger has a large-diameter portion, a small-diameter portion, and a step portion between the large-diameter portion and the small-diameter portion.
The metal member has a stepped portion facing surface facing the stepped portion on the side opposite to the seal facing surface.
A high-pressure fuel pump that regulates the movement of the plunger to the side opposite to the pressurizing chamber before mounting the high-pressure fuel pump by facing the stepped portion facing surface. In the high-pressure fuel pump according to claim 1 or 2.
The plunger has a large-diameter portion, a small-diameter portion, and a step portion between the large-diameter portion and the small-diameter portion.
The metal member is a high-pressure fuel pump having an inner peripheral side cylindrical portion formed by bending toward the step portion at a position overlapping the step portion in the radial direction. In the high-pressure fuel pump according to claim 1,
A high-pressure fuel pump in which a plurality of the through holes formed on the seal facing surface of the metal member are formed. In the high-pressure fuel pump according to claim 2.
The metal member is a high-pressure fuel pump arranged only inside the seal holding member in the radial direction and inside in the axial direction. In the high-pressure fuel pump according to claim 2.
The metal member is a high-pressure fuel pump that is arranged only radially inside the inner peripheral surface of the seal holding member that holds the outer peripheral portion of the plunger seal. In the high-pressure fuel pump according to claim 1 or 2.
A high-pressure fuel pump configured such that the seal facing surface of the metal member comes into contact with the plunger seal. In the high-pressure fuel pump according to claim 1 or 2.
The metal member is a high-pressure fuel pump made of metal having a thickness of 0.6 mm or less. In the high-pressure fuel pump according to claim 1 or 2.
The metal member is a high-pressure fuel pump made of a press-molded product. In the high-pressure fuel pump according to claim 2.
The seal holding member is a high-pressure fuel pump made of a press-molded product. In the high-pressure fuel pump according to claim 1,
A seal holding member for holding the plunger seal is provided.
The metal member includes an outer peripheral side cylindrical portion press-fitted into the inner peripheral portion of the seal holding member and a radial extension extending radially inward from the end of the outer peripheral side cylindrical portion on the plunger seal side. It has a portion and an inner peripheral side cylindrical portion formed so as to be folded back from the inner peripheral end portion of the radial extension portion to the side opposite to the plunger seal.
The through hole is a high-pressure fuel pump formed in the radial extension portion. In the high-pressure fuel pump according to claim 12.
The metal member has a plurality of the through holes at intervals in the circumferential direction, and also has a cross-linked portion connecting the outer peripheral side cylindrical portion and the inner peripheral side cylindrical portion between two adjacent through holes. ,
A high-pressure fuel pump in which the total area of the through holes formed in the radial extension is larger than the total area of the bridge formed in the radial extension. A plunger that changes the volume of the pressurizing chamber and
A plunger seal that slides into the outer peripheral surface of the plunger and
A first seal support member that supports the plunger seal from the outside in the radial direction and one end side in the axial direction,
A second seal support member that supports the plunger seal from the other end side in the axial direction is provided.
The first seal support member is provided on one end side in the axial direction, and is provided on the other end side in the axial direction and an insertion port for inserting the plunger seal and the second seal support member inside the first seal support member. It has a bottom portion formed with a through hole through which the plunger is inserted, and an inner peripheral surface having the same inner diameter formed in a predetermined range between the insertion port and the bottom portion.
The plunger seal is sandwiched between the inner peripheral surface of the first seal support member and the plunger so as to be located on the bottom side of the second seal support member.
A high-pressure fuel pump in which the second seal support member is press-fitted into the inner peripheral surface of the first seal support member so as to be located on the insertion port side with respect to the plunger seal.

Images