JP2019094819A - High-pressure fuel supply pump - Google Patents

Abstract

To provide a high-pressure fuel supply pump which prevents the flow-in of a lubricant at an engine side into the pump caused by a reciprocation motion of a plunger, and can secure cooling performance with respect to slide friction heat which is generated by the reciprocation motion of the plunger.SOLUTION: A high-pressure fuel supply pump comprises: a pump body 1 having a pressurization chamber 11 therein; a plunger 2 for increasing and decreasing a capacity of the pressurization chamber 11 by a reciprocation motion; a seal holder 7 having a sub-chamber 7a which can accept fuel leaking out of the pressurization chamber 11 along the plunger 2 therein; and a seal member 13 which is held in the seal holder 7 in a state that the seal member can slide-contact with an external peripheral face of the plunger 2, and seals the sub-chamber 7a from the outside (engine). The seal holder 7 holds the seal member 13 so that a first pressing force F1 for pressing a first portion 131a of the seal member 13 at the engine side to the inside of a radial direction becomes large compared with a second pressing force F2 for pressing a second portion 131b at the pressurization chamber 11 side to the inside of the radial direction.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a high pressure fuel supply pump for an internal combustion engine of a motor vehicle, and to a high pressure fuel supply pump provided with a seal member sliding on the outer peripheral surface of a reciprocating plunger.

  BACKGROUND ART In a direct injection type internal combustion engine in which fuel is directly injected into the combustion chamber of an internal combustion engine, a high pressure fuel supply pump for increasing the pressure of the fuel is widely used. As background art of this high pressure fuel supply pump, there is a thing of patent documents 1 statement, for example. In the high-pressure fuel supply pump described in Patent Document 1, a seal member is mounted on an outer peripheral surface of a piston plunger that pressurizes fuel in a pressure chamber by reciprocation so as to be in sliding contact therewith. It is fixed in the inner cylindrical surface. The seal member prevents the fuel in the pump from flowing into the internal combustion engine, and at the same time prevents the lubricating oil for lubricating the sliding portion in the internal combustion engine from flowing into the pump.

JP, 2010-106740, A

  Like a seal member of a high pressure fuel supply pump described in Patent Document 1, a seal member which prevents the outflow of fuel in the pump to the internal combustion engine side and prevents the inflow of lubricating oil of the internal combustion engine into the pump is Normally, the pressure is applied to both the pressure chamber side portion and the internal combustion engine side portion of the piston plunger with substantially the same magnitude of tightening force. That is, both the portion of the seal member for preventing the outflow of the fuel from the pump and the portion for preventing the inflow of the lubricating oil into the pump are in similar contact with the piston plunger.

  In such a case, since the viscosity of the lubricating oil is larger than the viscosity of the fuel, there is a concern that the lubricating oil on the internal combustion engine side may leak into the pump through the sliding portion between the piston plunger and the seal member. In order to prevent the inflow of lubricating oil into the pump by increasing the pressure on the piston plunger of the seal member against such concerns, seizing due to sliding friction between the piston plunger and the seal member, etc. The problem of frictional heat may occur.

  The present invention has been made to solve the above-mentioned problems, and its object is to prevent the inflow of lubricating oil on the internal combustion engine side into the pump by the reciprocating motion of the plunger and to reciprocate the plunger. An object of the present invention is to provide a high pressure fuel supply pump capable of securing a cooling performance against the generated sliding friction heat.

  The present application includes a plurality of means for solving the above-mentioned problems, and an example thereof is a pump body attached to an engine to which lubricating oil is supplied and having a pressure chamber inside, and the pressure by reciprocating motion. A plunger for increasing or decreasing the volume of the chamber, a seal holder internally forming a sub-chamber capable of receiving fuel leaking from the pressure chamber along the plunger, and a state capable of sliding contact with the outer peripheral surface of the plunger And a seal member held in the seal holder and sealing the sub-chamber from the engine, the seal holder pressing the first portion on the engine side of the seal member radially inward The seal member is characterized in that the pressure is greater than a second pressing force for pressing the second portion of the seal member on the pressure chamber side radially inward.

According to the present invention, the seal holder and the seal member are configured such that the tension force of the first portion of the seal member on the plunger is relatively larger than the tension force of the second portion. It is possible to prevent the inflow of lubricating oil on the side of the pump into the pump, and secure the cooling performance against the frictional heat due to the sliding of the plunger and the seal member by the lubricating action of the fuel on the sliding surface of the plunger and the seal member. be able to.
Problems, configurations, and effects other than the above are clarified by the description of the embodiments below.

BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram which shows the structure of the fuel supply system of a motor vehicle containing the high pressure fuel supply pump which concerns on the 1st Embodiment of this invention. FIG. 2 is a cross-sectional view showing the high-pressure fuel supply pump according to the first embodiment of the present invention in a state where it is cut along a plane along the axial direction of the plunger. It is sectional drawing which looked at the high pressure fuel supply pump which concerns on 1st Embodiment of this invention shown in FIG. 2 from the III-III arrow. FIG. 1 is a cross-sectional view showing a high-pressure fuel supply pump according to a first embodiment of the present invention cut in a plane including both axial centers of a plunger and a suction joint. FIG. 2 is an enlarged cross-sectional view of an electromagnetic suction valve mechanism that constitutes a part of the high-pressure fuel supply pump according to the first embodiment of the present invention. It is a sectional view showing the seal member which constitutes a part of high-pressure fuel supply pump concerning a 1st embodiment of the present invention in the state where it was expanded. It is sectional drawing which shows the seal holder which comprises some high pressure fuel supply pumps which concern on 1st Embodiment of this invention shown in FIG. 2, and its peripheral part in the expanded state. It is sectional drawing shown in the state which expanded the holding structure of the seal member of the seal holder shown in FIG. It is sectional drawing which shows the seal holder which comprises some high pressure fuel supply pumps which concern on the 2nd Embodiment of this invention, and the peripheral part in the state which expanded. It is sectional drawing shown in the state which expanded the holding structure of the seal member of the seal holder shown in FIG. It is sectional drawing which shows the seal holder which comprises some high pressure fuel supply pumps which concern on the 3rd Embodiment of this invention, and the peripheral part in the state which expanded. It is sectional drawing shown in the state which expanded the holding structure of the seal member of the seal holder shown in FIG.

Hereinafter, an embodiment of the high-pressure fuel supply pump of the present invention will be described with reference to the drawings.
First Embodiment
First, the configuration of a fuel supply system of a vehicle including a high-pressure fuel supply pump according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a conceptual view showing a configuration of a fuel supply system of an automobile including a high pressure fuel supply pump according to a first embodiment of the present invention.

  The broken line in FIG. 1 shows the pump body 1 which is the main body of the high pressure fuel supply pump. The mechanisms and components drawn inside the dashed line show what is incorporated into the pump body 1.

  In FIG. 1, the fuel supply system pressurizes and discharges a fuel tank 20 for storing fuel, a feed pump 21 for drawing up and delivering the fuel in the fuel tank 20, and low pressure fuel sent from the feed pump 21. A high pressure fuel supply pump and a plurality of injectors 24 for injecting high pressure fuel pressure-fed from the high pressure fuel supply pump are provided. The high pressure fuel supply pump is connected to the feed pump 21 via the suction pipe 28. The high pressure fuel supply pump pumps fuel to the injector 24 via the common rail 23. The injectors 24 are attached to the common rail 23 according to the number of cylinders of the engine. A pressure sensor 26 is mounted on the common rail 23. The pressure sensor 26 detects the pressure of the fuel discharged from the high pressure fuel supply pump.

  The high pressure fuel supply pump is applied to a so-called direct injection engine system in which the injector 24 directly injects fuel into the cylinder of the engine as an internal combustion engine. The high pressure fuel supply pump includes a pressurizing chamber 11 for pressurizing the fuel, an electromagnetic suction valve mechanism 300 as a capacity variable mechanism for adjusting the amount of fuel drawn into the pressurizing chamber 11, and fuel in the pressurizing chamber 11 It includes a plunger 2 that is pressurized by reciprocating motion, and a discharge valve mechanism 8 that discharges the fuel pressurized by the plunger. A metal damper 9 as a pressure pulsation reducing mechanism is provided on the upstream side of the electromagnetic suction valve mechanism 300 to reduce the pressure pulsation generated in the high pressure fuel supply pump from spreading to the suction pipe 28.

  The feed pump 21, the electromagnetic suction valve mechanism 300, and the injector 24 are electrically connected to an engine control unit (hereinafter referred to as an ECU) 27 and controlled by a control signal output from the ECU 27. A detection signal of the pressure sensor 26 is input to the ECU 27.

  The fuel in the fuel tank 20 is pumped up by a feed pump 21 driven based on a control signal of the ECU 27. The fuel is pressurized to an appropriate feed pressure by the feed pump 21 and is sent through the suction pipe 28 to the low pressure fuel suction port 10 a of the high pressure fuel supply pump. The fuel that has passed through the low pressure fuel suction port 10a reaches the suction port 31b of the electromagnetic suction valve mechanism 300 via the metal damper 9 and the suction passage 10d. The fuel that has flowed into the electromagnetic suction valve mechanism 300 passes through the suction valve 30 that opens and closes based on the control signal of the ECU 27. The fuel that has passed through the suction valve 30 is sucked into the pressure chamber 11 in the downward stroke of the reciprocating plunger 2 and pressurized in the pressure chamber 11 in the upward stroke of the plunger 2. The pressurized fuel is pressure-fed to the common rail 23 via the discharge valve mechanism 8. The high pressure fuel in the common rail 23 is injected into the cylinder of the engine by the injector 24 driven based on the control signal of the ECU 27.

  The high pressure fuel supply pump discharges a desired flow amount of fuel according to a control signal from the ECU 27 to the electromagnetic suction valve mechanism 300.

  Next, the detailed structure of the high-pressure fuel supply pump according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing the high-pressure fuel supply pump according to the first embodiment of the present invention in a state cut along a plane along the axial direction of the plunger. FIG. 3 is a cross-sectional view of the high-pressure fuel supply pump according to the first embodiment of the present invention shown in FIG. 2 as viewed from the arrow III-III. FIG. 4 is a cross-sectional view showing the high-pressure fuel supply pump according to the first embodiment of the present invention in a state cut at a plane including both axial centers of the plunger and the suction joint. FIG. 5 is a cross-sectional view showing, in an enlarged state, an electromagnetic suction valve mechanism that constitutes a part of the high-pressure fuel supply pump according to the first embodiment of the present invention. In addition, FIG. 5 is shown in the state which abbreviate | omitted the connector.

  2 and 3, the high pressure fuel supply pump includes a pump body 1 having a pressure chamber 11 therein, a plunger 2 assembled to the pump body 1, an electromagnetic suction valve mechanism 300, a discharge valve mechanism 8 and a relief valve mechanism 200. And a metal damper 9 as a pressure pulsation reducing mechanism. The high pressure fuel supply pump is attached to, for example, an engine block of an engine. The engine is supplied with lubricating oil (including engine oil) for lubricating each part in the engine.

  The pump body 1 is in close contact with the pump mounting portion 90 of the engine using a mounting flange 1e integrally formed on one end side (the lower side in FIG. 2), and is fixed by a plurality of bolts. An O-ring 61 is fitted on the outer peripheral surface of the pump body 1 on the side of the mounting flange 1 e of the pump body 1 to be fitted with the pump mounting portion 90. The O-ring 61 seals between the pump mounting portion 90 and the pump body 1 to prevent engine oil and the like from leaking out of the engine.

  As shown in FIG. 2 and FIG. 4, the pump body 1 has a bottomed two-step stepped first accommodation hole with one end side (the lower side in FIG. 2 and FIG. 4) open at the center portion. 1a is provided. In the first accommodation hole portion 1a, a small diameter portion including the bottom surface thereof forms a part of the pressure chamber 11. The cylinder 6 is press-fitted and fixed to the middle diameter portion of the first accommodation hole portion 1a. The cylinder 6 is pressed toward the pressurizing chamber 11 by the fixed portion 1f obtained by plastically deforming a part of the pump body 1 to the inner peripheral side, and the cylinder 6 is on the pressurizing chamber 11 side (upper side in FIGS. 2 and 4) The end face 6 b is press-bonded to the step surface of the first accommodation hole 1 a of the pump body 1. Thus, the fuel in the pressure chamber 11 is sealed so as not to leak to the low pressure side from the contact portion between the wall surface of the first accommodation hole portion 1a of the pump body 1 and the end surface 6b on the pressure chamber 11 side of the cylinder 6. The cylinder 6 has the plunger 2 slidably disposed therein, and guides the reciprocating motion of the plunger 2.

  The plunger 2 increases and decreases the volume of the pressure chamber 11 by reciprocating movement, and the large diameter portion 2a sliding on the cylinder 6 and the opposite side to the pressure chamber 11 from the large diameter portion 2a, It is comprised by the small diameter part 2b smaller diameter than the large diameter part 2a. A tappet 3 is provided on the tip end side (lower end side in FIGS. 2 and 4) of the small diameter portion 2 b of the plunger 2. The tappet 3 converts the rotational movement of a cam 93 (cam mechanism) attached to the camshaft of the engine into a linear reciprocating movement and transmits it to the plunger 2. A retainer 15 is provided at the tip of the small diameter portion 2 b of the plunger 2. The plunger 2 is crimped to the tappet 3 by the biasing force of the spring 4 through the retainer 15. Thus, the plunger 2 can be reciprocated with the rotational movement of the cam 93.

  The seal holder 7 is press-fitted to the large diameter portion of the first accommodation hole portion 1 a of the pump body 1 and fixed by welding. The seal holder 7 is configured to cover the outside of a part of the plunger 2 with a gap on the engine side (lower side in FIGS. 2 and 4) than the cylinder 6. The seal holder 7 forms therein a sub chamber 7 a as a space capable of receiving the fuel leaking from the pressure chamber 11 along the sliding portions of the plunger 2 and the cylinder 6.

  A plunger seal 13 is installed at the small diameter portion 2 b of the plunger 2. The plunger seal 13 is held in the seal holder 7 in a state where it can be in sliding contact with the outer peripheral surface of the small diameter portion 2 b. The plunger seal 13 seals the sub chamber 7a from the engine (outside), seals the fuel in the sub chamber 7a when the plunger 2 reciprocates, and prevents the fuel from flowing out to the engine side. The lubricating oil functions as a seal member that prevents the lubricating oil from flowing into the interior of the pump body 1 from the engine side.

  In the seal holder 7, the pressing member 16 is press-fitted and held at a position closer to the pressure chamber 11 than the plunger seal 13. The pressing member 16 functions as a movement restricting member that restricts the movement of the plunger seal 13 toward the pressure chamber 11 due to the sliding of the plunger 2 and the plunger seal 13 when the plunger 2 reciprocates.

  The detailed configuration and structure of the plunger seal 13 and the seal holder 7 of the present embodiment will be described later.

  Further, as shown in FIG. 3, a suction joint 51 is attached to the outer peripheral portion of the pump body 1. A suction pipe 28 (see FIG. 1) is connected to the suction joint 51, and the fuel from the feed pump 21 is supplied to the inside of the high pressure fuel supply pump through the low pressure fuel suction port 10 a of the suction joint 51. As shown in FIGS. 3 and 4, a suction filter 52 is attached to the downstream side of the low pressure fuel suction port 10a. The suction filter 52 serves to prevent foreign matter present between the fuel tank 20 (see FIG. 1) and the pump body 1 from being absorbed by the high pressure fuel pump by the flow of fuel.

  Furthermore, as shown in FIGS. 2 and 3, the pump body 1 is provided with a second accommodation hole 300H from the outer peripheral wall toward the pressure chamber 11. An electromagnetic suction valve mechanism 300 for supplying fuel to the pressure chamber 11 is attached to the second accommodation hole 300H. As shown in FIG. 5, the electromagnetic suction valve mechanism 300 mainly includes a suction valve portion mainly constituted by the suction valve 30, a solenoid mechanism portion mainly constituted by the rod 35 and the anchor portion 36, and the electromagnetic coil 43. It is roughly divided into the coil part comprised by this, and is arrange | positioned at the suction side of the pressurization chamber 11. As shown in FIG.

  The suction valve portion includes a suction valve 30, a suction valve housing 31, a suction valve stopper 32, and a suction valve biasing spring 33.

  The suction valve housing 31 has, for example, a cylindrical valve housing 31h for housing the suction valve 30 on one side (right side in FIG. 5), and an annular suction valve seat that protrudes to the inner peripheral side of the valve housing 31h. And 31a. An outer peripheral side of the suction valve housing 31 is press-fitted and fixed to the second accommodation hole 300 H of the pump body 1. A plurality of suction ports 31 b are radially provided in the suction valve housing 31 so as to communicate with the opening 30 d of the suction valve seat portion 31 a. A suction valve stopper 32 is press-fitted and fixed to the valve accommodating portion 31 h of the suction valve housing 31.

  The suction valve 30 is disposed in the valve accommodating portion 31 h of the suction valve housing 31 and faces the suction valve seat portion 31 a. The suction valve 30 is closed by coming into contact with the suction valve seat portion 31a, and is brought into contact with the suction valve stopper 32 when the valve is opened. That is, the distance between the suction valve seat portion 31a and the suction valve stopper 32 is a stroke in which the suction valve 30 moves at the time of the on-off valve. The suction valve biasing spring 33 is disposed between the suction valve 30 and the suction valve stopper 32, and biases the suction valve 30 in the valve closing direction.

  The suction valve housing 31 is integrally formed with a rod guide 37 described later located on the other side (left side in FIG. 5).

  The solenoid mechanism includes a rod 35 and an anchor 36 which are movable parts, a rod guide 37 which is a fixed part, an outer core 38 and a fixed core 39, a rod biasing spring 40 and an anchor biasing spring 41. And consists of.

  The rod 35 and the anchor portion 36 are configured as separate members. The rod 35 is axially slidably held on the inner peripheral side of the rod guide 37. The rod 35 is configured separately from the suction valve 30, and the tip of one side (right side in FIG. 5) is configured to be able to contact and separate from the suction valve 30. The rod 35 has a rod collar 35a at the end on the other side (left side in FIG. 5). The anchor portion 36 is slidably held on the outer peripheral side of the rod 35 at the inner peripheral side. That is, both the rod 35 and the anchor portion 36 are axially slidable within a geometrically restricted range. The anchor portion 36 has at least one axially extending through hole 36a in order to move axially freely and smoothly in the fuel. Thereby, the restriction of the movement of the anchor portion 36 due to the pressure difference on both sides in the axial direction of the anchor portion 36 is eliminated as much as possible.

  The rod guide 37 guides the reciprocation of the rod 35. As described above, the rod guide 37 is integrally formed with the suction valve housing 31, and the cylindrical central bearing portion 37b is provided on the center side of the anchor portion 36 side end (the left end in FIG. 5). Have. Similar to the anchor portion 36, the rod guide 37 is provided with a through hole 37a penetrating in the axial direction. Thereby, the pressure in the chamber which accommodates the anchor part 36 does not prevent the movement of the anchor part 36, and the anchor part 36 can move freely freely.

  The outer core 38 is formed of a stepped cylindrical member. A rod guide 37 is press-fit fitted on one axial side (right side in FIG. 5) on the inner peripheral side of the outer core 38. The anchor portion 36 is slidably disposed on the other axial side (left side in FIG. 5). The large diameter portion on one side of the outer core 38 is inserted into the second accommodation hole 300H of the pump body 1, and the outer peripheral side is fixed by welding.

  The fixed core 39 is disposed such that the end face on one side (the right side in FIG. 5) faces the end face on the rod collar 35a side of the anchor 36. The one end surface of the fixed core 39 and the end surface of the anchor portion 36 opposed thereto constitute a magnetic attraction surface S on which a magnetic attraction force acts between each other. When the suction valves 30 are open, they face each other via a magnetic gap.

  A rod biasing spring 40 is disposed between the fixed core 39 and the rod collar 35a. The rod biasing spring 40 applies a biasing force in a direction in which the rod 35 contacts the suction valve 30 and pulls the suction valve 30 away from the suction valve seat portion 31 a, that is, in the valve opening direction of the suction valve 30.

  The anchor biasing spring 41 is inserted into the central bearing 37 b of the rod guide 37 at one end, and is arranged to apply a biasing force to the anchor 36 toward the rod collar 35 a while maintaining the same axis as the rod 35. It is assumed. The amount of movement of the anchor portion 36 is set to be larger than the amount of movement 30 e of the suction valve 30. It is for the suction valve 30 to close reliably.

  Since the rod 35 and the rod guide 37 slide with each other, and the rod 35 repeatedly collides with the suction valve 30, the martensitic stainless steel is heat-treated in consideration of hardness and corrosion resistance. Since the anchor portion 36 and the fixed core 39 form a magnetic circuit, magnetic stainless steel is used. The rod biasing spring 40 and the anchor biasing spring 41 use austenitic stainless steel in consideration of corrosion resistance.

  According to the above configuration, the suction valve portion and the solenoid mechanism portion are configured by arranging the three springs organically. The suction valve biasing spring 33 of the suction valve portion, the rod biasing spring 40 of the solenoid mechanism portion, and the anchor portion biasing spring 41 correspond to this. The rod biasing spring 40 is set to have a biasing force that keeps the suction valve 30 open while the electromagnetic coil 43 is not energized. In the present embodiment, any spring uses a coil spring, but any configuration is possible as long as a biasing force can be obtained.

  As shown in FIGS. 2 and 5, the coil portion has a connector 47 having a first yoke 42, an electromagnetic coil 43, a second yoke 44, a bobbin 45, and two (only one is shown in FIG. 2) terminals 46. It consists of

  The electromagnetic coil 43 is obtained by winding a copper wire around the bobbin 45 a plurality of times. The electromagnetic coil 43 is assembled on the outer peripheral side of the fixed core 39 and the outer core 38 in a state of being surrounded by the first yoke 42 and the second yoke 44.

  The hole at the central portion of the first yoke 42 is press-fitted and fixed to the small diameter portion of the outer core 38 of the solenoid mechanism. The outer peripheral side of the second yoke 44 is press-fitted and fixed to the inner peripheral side of the first yoke 42. Further, the inner diameter side of the second yoke 44 is in contact with the outer periphery of the fixed core 39 of the solenoid mechanism or is in close proximity with a slight clearance.

  The two terminals 46 of the connector 47 have a configuration in which one end thereof is connected to both ends of the electromagnetic coil 43 so as to be conductive and the other end can be connected to the ECU 27 side. Both terminals 46 are molded integrally with the main body of the connector 47.

  The first yoke 42 and the second yoke 44 are both formed of a magnetic stainless steel material to form a magnetic circuit and in consideration of corrosion resistance. The main body portions of the bobbin 45 and the connector 47 are formed of a high-strength heat-resistant resin in consideration of the strength characteristics and the heat resistance characteristics. The electromagnetic coil 43 uses copper and the terminal 46 uses brass plated with metal.

  Thus, a magnetic circuit is formed by the outer core 38, the first yoke 42, the second yoke 44, the fixed core 39, and the anchor portion 36. In this magnetic circuit, when a current is applied to the electromagnetic coil 43, a magnetic attraction force is generated between the fixed core 39 and the anchor portion 36, and a attraction force is generated. Since the outer core 38 does not extend to the fixed core 39, substantially all of the magnetic flux passes between the fixed core 39 and the anchor portion 36. As a result, the magnetic attraction between the fixed core 39 and the anchor portion 36 can be efficiently obtained.

  Further, as shown in FIG. 3, the pump body 1 is provided with a third accommodation hole 8H from the outer peripheral wall at a position different from the second accommodation hole 300H toward the pressure chamber 11. A discharge valve mechanism 8 for discharging the fuel from the pressurizing chamber 11 to a discharge passage 12b described later is attached to the third accommodation hole 8H. The discharge valve mechanism 8 is disposed on the outlet side of the pressure chamber 11, and directs the discharge valve seat 8a, the discharge valve 8b coming into contact with and separated from the discharge valve seat 8a, and the discharge valve 8b toward the discharge valve seat 8a. It comprises a discharge valve spring 8c that is biased and a discharge valve stopper 8d that determines the stroke (moving distance) of the discharge valve 8b. The discharge valve seat 8a is held, for example, in the third accommodation hole 8H of the pump body 1 by press-fitting. The discharge valve stopper 8d and the pump body 11 are joined by welding at the contact portion 8e, thereby blocking the leakage of the fuel to the outside. A discharge valve chamber 12a is formed on the secondary side of the discharge valve 8b in the third accommodation hole 8H to which the discharge valve mechanism 8 is attached.

  In the state where there is no fuel pressure difference between the pressure chamber 11 and the discharge valve chamber 12a, the discharge valve 8b is crimped to the discharge valve seat 8a by the biasing force of the discharge valve spring 8c and is in a closed state. Only when the fuel pressure in the pressurizing chamber 11 becomes larger than the fuel pressure in the discharge valve chamber 12a, the discharge valve 8b opens against the biasing force of the discharge valve spring 8c. When the discharge valve 8b is opened, the high pressure fuel in the pressure chamber 11 is discharged to the common rail 23 through the discharge valve chamber 12a, the discharge passage 12b described later, and the fuel discharge port 12 described later.

  The discharge valve 8b contacts the discharge valve stopper 8d when the valve is opened, 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 high pressure fuel discharged to the discharge valve chamber 12a from flowing back into the pressurizing chamber 11 again due to the delay in closing of the discharge valve 8b due to the excessive stroke, and the efficiency of the high pressure fuel supply pump is lowered. Can be suppressed. Further, the outer peripheral surface of the discharge valve stopper 8d is configured to guide the discharge valve 8b so that the discharge valve 8b moves only in the stroke direction when the valve opening and closing motion is repeated. With the above configuration, the discharge valve mechanism 8 functions as a check valve that restricts the flow direction of the fuel.

  Furthermore, as shown in FIGS. 2 and 4, a housing recess 1 p is provided on the side (upper side in FIGS. 2 and 4) opposite to the mounting flange 1 e of the pump body 1. A cup-shaped damper cover 14 is fixed to the pump body 1 by welding so as to cover the housing recess 1p. A low pressure fuel chamber 10 is formed by the accommodation recess 1 p on the other end side of the pump body 1 and the damper cover 14. The low pressure fuel chamber 10 communicates with the low pressure fuel suction port 10a, and also communicates with the suction port 31b of the electromagnetic suction valve mechanism 300 via the suction passage (low pressure fuel flow path) 10d. The low pressure fuel chamber 10 is also in communication with the sub chamber 7a via the communication passage 10e.

  In the low pressure fuel chamber 10, a metal damper 9 as a pressure pulsation reducing mechanism is disposed. That is, the low pressure fuel chamber 10 constitutes a damper chamber that accommodates the metal damper 9. A holding member 9a is disposed between the metal damper 9 and the housing recess 1p of the pump body 1, and is held in the low pressure fuel chamber 10 in a state where the metal damper 9 is held by the holding member 9a and the damper cover 14 It is done. The metal damper 9 is formed of, for example, a metal diaphragm damper in which two corrugated disc-like metal plates are laminated at the outer periphery thereof and an inert gas such as argon is injected therein.

  Further, as shown in FIGS. 2 and 3, the pump body 1 is directed from the outer peripheral wall of the pump body 1 to the pressure chamber 11 at a position facing the second accommodation hole 300 H with the pressure chamber 11 interposed therebetween. A stepped fourth accommodation hole 200H is provided. A relief valve mechanism 200 is attached to the small diameter side of the fourth accommodation hole 200H. A discharge joint 60 is fixed on the large diameter side of the fourth accommodation hole 200H by welding so as to close the fourth accommodation hole 200H. The fourth accommodation hole 200H communicates with the third accommodation hole 8H via the discharge passage 12b. The fourth accommodation hole 200H also communicates with the pressure chamber 11 via the relief passage 210.

  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 formed in a cylindrical shape with a bottom, and has a tapered seat portion on the bottom side. In the relief body 201, a relief valve holder 203 is disposed movably on the bottom side, and a spring stopper 205 is press-fitted and fixed on the opening side. One end of the relief spring 204 is in contact with the relief valve holder 203, and the other end is in contact with the spring stopper 205. The biasing force of the relief spring 204 is loaded via the relief valve holder 203, the relief valve 202 is pressed by the seat portion of the relief body 201, and shuts off fuel in cooperation with the seat portion. The opening pressure of the relief valve 202 is determined by the biasing force of the relief spring 204. The biasing force of the relief spring 204 is adjusted by the position of the press-fit of the spring stopper 205.

  A fuel discharge port 12 is formed in the discharge joint 60, and a fuel passage is secured. The discharge joint 60 is configured to be able to house a part of the relief valve mechanism 200 therein.

  The pressurizing chamber 11 is constituted by the pump body 1, the cylinder 6, the plunger 2, the electromagnetic suction valve mechanism 300, and the discharge valve mechanism 8.

  Next, the operation of the high pressure fuel supply pump will be described with reference to FIGS.

  When the plunger 2 moves to the cam 93 side by the rotation of the cam 93 shown in FIG. 2 and is in the suction stroke, the volume of the pressure chamber 11 increases and the fuel pressure in the pressure chamber 11 decreases. When the fuel pressure in the pressure chamber 11 becomes lower than the pressure of the suction port 31b in this stroke, the suction valve 30 is opened. Therefore, the fuel flows into the pressurizing chamber 11 through the opening 30d of the suction valve 30, as shown in FIG.

  After the end of the suction stroke, the plunger 2 switches to the upward movement and shifts to the compression stroke. Here, the non-energized state of the electromagnetic coil 43 is maintained, and no magnetic bias is generated. In this case, the suction valve 30 is maintained in the open state by the biasing force of the rod biasing spring 40. The volume of the pressure chamber 11 decreases with the compression motion of the plunger 2. However, when the suction valve 30 is opened, the fuel once sucked into the pressure chamber 11 is again drawn through the opening 30d of the suction valve 30 into the suction passage. Since the pressure is returned to 10d, the pressure in the pressure chamber 11 does not rise. This process is called a return process.

  In this state, when the control signal of the ECU 27 (see FIG. 1) is applied to the electromagnetic suction valve mechanism 300, a current flows in the electromagnetic coil 43 via the terminal 46. Then, a magnetic attraction force acts between the fixed core 39 and the anchor portion 36, whereby the magnetic biasing force overcomes the biasing force of the rod biasing spring 40 and the rod 35 moves in the direction away from the suction valve 30. Therefore, the suction valve 30 is closed by the biasing force of the suction valve biasing spring 33 and the flow of fuel into the suction passage 10d. By closing the suction valve 30, the fuel pressure in the pressure chamber 11 rises in response to the upward movement of the plunger 2, and when it becomes equal to or higher than the pressure of the fuel discharge port 12, the discharge valve 8b of the discharge valve mechanism 8 shown in FIG. Opens. As a result, the high-pressure fuel in the pressure chamber 11 is discharged from the fuel discharge port 12 through the discharge valve chamber 12a and the discharge passage 12b, and is supplied to the common rail 23 (see FIG. 1). This stroke is called a discharge stroke.

  That is, the compression stroke (the rising stroke from the lower start point to the upper start point) of the plunger 2 shown in FIG. 2 includes a return stroke and a discharge stroke. Further, by controlling the energization timing of the electromagnetic coil 43 of the electromagnetic suction valve mechanism 300, it is possible to control the flow rate of the high pressure fuel to be discharged. If the timing for energizing the electromagnetic coil 43 is advanced, the proportion of the return stroke during the compression stroke becomes smaller and the proportion of the discharge stroke becomes greater. That is, while the amount of fuel returned to the suction passage 10d decreases, the amount of fuel discharged at high pressure increases. On the other hand, if the timing of energizing is delayed, the proportion of the return stroke in the compression stroke becomes large, and the proportion of the discharge stroke becomes small. That is, while the amount of fuel returned to the suction passage 10d increases, the amount of fuel discharged at high pressure decreases. The energization timing of the electromagnetic coil 43 is controlled by a command from the ECU 27.

  As described above, by controlling the energization timing of the electromagnetic coil 43, it is possible to control the amount of high pressure discharged fuel to the amount required by the engine.

  In the above-described capacity control of the pump, when the fuel once flowing into the pressure chamber 11 is returned to the suction passage 10d again through the suction valve 30 in the open state (in the case of the return stroke), the pressure chamber 11 to the suction passage 10d The backflow of the fuel generates pressure pulsations in the low pressure fuel chamber 10. This pressure pulsation is absorbed and reduced by the expansion and contraction of the metal damper 9 disposed in the low pressure fuel chamber 10.

  Further, as shown in FIG. 4, the volume of the sub chamber 7 a is increased or decreased by the reciprocating motion of the plunger 2 having the large diameter portion 2 a and the small diameter portion 2 b. When the plunger 2 is lowered, the volume of the sub chamber 7a is reduced, and the flow of fuel from the sub chamber 7a to the low pressure fuel chamber 10 via the communication passage 10e is generated. On the other hand, at the time of ascent, the volume of the sub chamber 7a increases, and the flow of fuel from the low pressure fuel chamber 10 to the sub chamber 7a via the communication passage 10e occurs. As a result, the fuel flow rate into and out of the pump in the suction stroke or return stroke of the pump can be reduced, and pressure pulsations generated inside the pump can be reduced.

  When the pressure of the fuel discharge port 12 becomes abnormally high pressure due to a failure of the electromagnetic suction valve mechanism 300 shown in FIG. 3 or the like and becomes larger than the set pressure of the relief valve mechanism 200, fuel of abnormally high pressure flows in the relief passage 210. The pressure is relieved to the pressure chamber 11 via

  By the way, as shown in FIG. 2, due to the reciprocation of the plunger 2, the fuel in the pressure chamber 11 leaks into the sub-chamber 7 a along the sliding portion of the plunger 2 and the cylinder 6. The plunger seal 13 held in the seal holder 7 prevents the fuel in the sub chamber 7a from flowing out to the engine side (the lower side in FIG. 2). Further, the plunger seal 13 also prevents the lubricating oil on the engine side from flowing into the sub chamber 7 a by the reciprocating motion of the plunger 2. That is, the plunger seal 13 seals the lubricating oil of the engine by the first portion on the cam 93 side (the lower side in FIG. 2) to prevent the inflow into the sub chamber 7a, and at the same time The fuel in the auxiliary chamber 7a is sealed by the second portion (upper side in FIG. 2) to prevent the outflow to the engine side.

  In the conventional high-pressure fuel supply pump, the pressing force of the plunger seal against the plunger is substantially equal to the pressurizing chamber side (the part for sealing the lubricating oil on the engine side) and the cam side (the part for sealing the fuel on the pump side). The plunger seal and the seal holder are configured to be the same size. In such a conventional configuration, since the viscosity of the lubricating oil is larger than the viscosity of the fuel, there is a concern that the lubricating oil on the engine side may flow into the auxiliary chamber via the sliding portion between the plunger and the plunger seal. When the lubricating oil flows into the pump, it may react with the fuel in the pump to generate foreign matter, which may cause a failure. In order to prevent the lubricating oil from flowing into the sub chamber by uniformly increasing the tension force on the cam side portion and the pressure chamber side portion of the plunger seal against such concerns, the plunger and the plunger seal There is a possibility that the problem of frictional heat such as seizing due to sliding friction with it may occur.

  Therefore, in the present embodiment, the problem is solved by configuring the plunger seal and the seal holder as follows. First, the configuration and structure of the plunger seal will be described with reference to FIG. FIG. 6 is a cross-sectional view showing a seal member constituting a part of the high-pressure fuel supply pump according to the first embodiment of the present invention in an enlarged state.

  As shown in FIG. 6, the plunger seal 13 is formed in a substantially cylindrical shape, and is mounted on the plunger 2 in a state where its inner peripheral surface can be in sliding contact with the outer peripheral surface of the cylindrical plunger 2 (see FIG. 2) It is configured to be. In the main body portion 131 of the plunger seal 13, the first portion 131a on one side in the axial direction divided by the bisecting plane P in the axial direction (longitudinal direction) and the second portion 131b on the other side in the axial direction are equally divided. It is configured to have a substantially plane-symmetrical shape with respect to the plane P. Therefore, when assembling the plunger seal 13, the plunger seal 13 may be assembled from the first portion 131a side or from the second portion 131b side. That is, there is no limitation on the assembling direction of the plunger seal 13 with respect to the plunger 2, and the assembling operation can be performed efficiently.

  Annular groove portions 131 d are provided on both axial end surfaces of the main body portion 131 of the plunger seal 13. A sealing spring 1132 is disposed in each annular groove 131 d. The spring 132 biases the main body portion 131 of the plunger seal 13 in the radial direction. That is, the spring 132 presses the inner peripheral surface of the main body portion 131 to the plunger 2 and presses the outer peripheral surface of the main body portion 131 to the seal holder 7. The spring 132 is, for example, a leaf spring.

  Next, the configuration and structure of the seal holder 7 will be described using FIGS. 7 and 8. FIG. 7 is a cross-sectional view showing, in an enlarged state, a seal holder which constitutes a part of the high-pressure fuel supply pump according to the first embodiment of the present invention shown in FIG. FIG. 8 is a cross-sectional view showing the holding structure of the seal member of the seal holder shown in FIG. 7 in an enlarged state.

  In FIG. 7, the seal holder 7 includes a bottomed inner cylindrical portion 71, an outer cylindrical portion 72 located outside the inner cylindrical portion 71, and a cylinder 6 of an open end of the inner cylindrical portion 71 and the outer cylindrical portion 72. It is comprised by the annular part 73 which connects with the front-end | tip part of the side. The seal holder 7 is fixed by welding by pressing the outer peripheral surface of the outer cylindrical portion 72 into the large diameter portion of the first accommodation hole portion 1 a of the pump body 1. A part of the spring 4 is accommodated in a space formed by the inner cylindrical portion 71, the outer cylindrical portion 72, and the annular portion 73, and one end side of the spring 4 is in contact with the annular portion 73. That is, the annular portion 73 functions as a spring seat of the spring 4.

  The bottom portion 75 of the inner cylindrical portion 71 is provided with an insertion hole 75a through which the plunger 2 can be inserted, and the inner cylindrical portion 71 receives a portion of the plunger 2 when the plunger 2 is inserted into the insertion hole 75a. doing. Inside the inner cylindrical portion 71, the plunger seal 13 and the pressing member 16 are arranged in order from the bottom portion 75 side.

  The inner cylindrical portion 71 has, for example, a bottom portion 75 having an insertion hole 75a, a first cylindrical portion 76 extending from the bottom portion 75 to the cylinder 6 side and holding the plunger seal 13 therein, and a first cylindrical portion 76. And the second cylindrical portion 77 which holds the pressing member 16 inside. An auxiliary chamber 7 a is formed between the second cylindrical portion 77 and the plunger 2.

  The inner circumferential surface 79 of the first tubular portion 76 constitutes a holding inner circumferential surface for holding the plunger seal 13 as shown in FIG. An inner circumferential surface 79 of the first cylindrical portion 76 as a holding inner circumferential surface is a first holding surface 79a for holding a first portion 131a on the engine side (lower side in FIG. 8) of the plunger seal 13; The second portion 131b on the pressure chamber 11 side (see FIG. 2) (the upper side in FIG. 8) on the pressure chamber 11 side (the upper side in FIG. 8); doing. The inner circumferential surface 79 is formed of a tapered surface which expands outward in the radial direction from the first holding surface 79 a side to the second holding surface 79 b side. On the other hand, the outer peripheral surface 80 of the first cylindrical portion 76 is formed of a cylindrical surface.

  In the plunger seal 13 and the seal holder 7 configured as described above, when the plunger seal 13 is press-fitted and held on the inner peripheral surface 79 of the first cylindrical portion 76, the plunger seal 13 is deformed along the tapered surface of the inner peripheral surface 79. As a result, the first portion 131a of the plunger seal 13 radially contracts more than the second portion 131b. In other words, the first pressing force F1 which causes the seal holder 7 to press the first portion 131a of the plunger seal 13 radially inward pushes the second portion 131b of the plunger seal 13 radially inward. Hold the plunger seal 13 so as to be larger than. Therefore, the spring 132 on the first portion 131a side of the plunger seal 13 contracts more than the spring 132 on the second portion 131b side, and the restoring force of the spring 13b on the first portion 131a side restores the spring 132 on the second portion 131b side. It becomes bigger than power.

  Therefore, the tension on the plunger 2 of the first portion 131a of the plunger seal 13 is relatively larger than the tension on the second portion 131b. As a result, it is possible to prevent the lubricating oil on the engine side from flowing into the sub-chamber 7a shown in FIG. 7 through the sliding portion between the first portion 131a of the plunger seal 13 and the plunger 2.

  Further, since the tension force of the second portion 131b of the plunger seal 13 is relatively smaller than that of the first portion 131a, the sliding surface between the second portion 131b of the plunger seal 13 and the plunger 2 is in the sub chamber 7a. Fuel leaks slightly. The fuel leaked to the sliding surface between the plunger seal 13 and the plunger 2 lubricates and cools the sliding surface, thereby suppressing the generation of sliding frictional heat.

  When the reciprocating plunger 2 slides on the plunger seal 13, the plunger seal 13 may move in the axial direction (vertical direction in FIG. 8) of the plunger 2 along with the movement of the plunger 2. In the present embodiment, the bottom portion 75 of the inner cylindrical portion 71 of the seal holder 7 functions as a movement restricting portion that restricts the movement of the plunger seal 13 to the engine side (downward in FIG. 8). Similarly, the pressing member 16 functions as a movement restricting portion that restricts movement of the plunger seal 13 to the pressure chamber 11 (see FIG. 2) side (upper side in FIG. 8).

  As described above, according to the high-pressure fuel supply pump according to the first embodiment of the present invention, the tension force of the first portion 131a of the plunger seal 13 (seal member) against the plunger 2 is the tension of the second portion 131b. Since the plunger seal 13 (seal member) and the seal holder 7 are configured to be relatively larger than the force, the inflow of lubricating oil on the engine (engine) side by the reciprocating motion of the plunger 2 It is possible to prevent the friction between the plunger 2 and the plunger seal 13 (seal member) by the lubricating action of the fuel on the sliding surface of the plunger 2 and the plunger seal 13 (seal member). can do.

  Further, according to the present embodiment, the inner peripheral surface 79 holding the plunger seal 13 of the seal holder 7 is a first holding surface 79 a holding the first portion 131 a of the plunger seal 13, and the second holding surface of the plunger seal 13. Since the portion 131b is held and provided with the second holding surface 79b located radially outward of the first holding surface 79a, the tension force of the first portion 131a and the second portion 131b of the plunger seal 13 The difference in size can be caused by the shape of the inner peripheral surface of the seal holder 7.

  Furthermore, according to the present embodiment, a tapered surface in which the inner peripheral surface 79 of the first cylindrical portion 76 of the seal holder 7 is expanded radially outward from the first holding surface 79a side to the second holding surface 79b side. Since the inner circumferential surface 79 of the first tubular portion 76 is easy to process.

  Further, according to the present embodiment, since the pressing member 16 is held in the seal holder 7 at a position closer to the pressure chamber 11 than the plunger seal 13, the pressure chamber 11 of the plunger seal 13 by reciprocation of the plunger 2 is You can regulate the movement to the side.

  Furthermore, according to the present embodiment, the plunger seal 13 is configured to have a shape of plane symmetry with respect to the bisecting plane P in the length direction (axial direction). The orientation is optional, and misassembly can be prevented. As a result, efficient assembly work is possible.

  Furthermore, according to the present embodiment, since the plunger seal 13 is provided with the spring 132 for biasing the first portion 131a and the second portion 131b in the radial direction, the tension force of the plunger seal 13 is It can be made to act reliably.

  In addition, according to the present embodiment, the electromagnetic suction valve mechanism 300 is disposed on the suction side of the pressure chamber 11, the damper chamber 10 is provided on the upstream side of the electromagnetic suction valve mechanism 300, and pressure pulsation is generated in the damper chamber 10. The pressure pulsation reduction mechanism (metal damper) 9 for absorbing the pressure is arranged, and the communication passage 10e that connects the sub chamber 7a and the damper chamber 10 is provided in the pump body 1, so pressure pulsation generated inside the pump can be reliably reduced. can do.

  Next, a high-pressure fuel supply pump according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing, in an enlarged state, a seal holder that constitutes a part of the high-pressure fuel supply pump according to the second embodiment of the present invention and the periphery thereof. FIG. 10 is a cross-sectional view showing the holding structure of the seal member of the seal holder shown in FIG. 9 in an enlarged state. In FIGS. 9 and 10, the same reference numerals as those shown in FIGS. 1 to 8 denote the same parts, so the detailed description thereof will be omitted.

  The high-pressure fuel supply pump according to the second embodiment of the present invention shown in FIGS. 9 and 10 differs from the high-pressure fuel supply pump according to the first embodiment in the inner cylindrical portion 71A of the seal holder 7A. It is the shape of the inner circumferential surface 79A of the first tubular portion 76A. Specifically, the inner peripheral surface 79A of the first cylindrical portion 76A is composed of a first holding surface 79c consisting of a cylindrical surface and a second holding surface 79d consisting of a cylindrical surface larger in inner diameter than the first holding surface 79c. It is configured. That is, on the inner circumferential surface 79A of the first cylindrical portion 76A, a step is formed by the first holding surface 79c and the second holding surface 79d.

  In the plunger seal 13 and the seal holder 7A configured as described above, when the plunger seal 13 is press-fitted and held on the inner peripheral surface 79A of the first cylindrical portion 76A, the plunger seal 13 and the first holding surface 79c of the inner peripheral surface 79A. Due to the difference in level with the second holding surface 79d, the first portion 131a of the plunger seal 13 contracts in the radial direction more than the second portion 131b. In other words, the seal holder 7A presses the first portion 131a of the plunger seal 13 radially inward, and the first pressing force F1 presses the second portion 131b of the plunger seal 13 radially inward. Hold the plunger seal 13 so as to be larger than.

  Therefore, the tension on the plunger 2 of the first portion 131a of the plunger seal 13 is relatively larger than the tension on the second portion 131b. As a result, it is possible to prevent the lubricating oil on the engine side from flowing into the sub-chamber 7a shown in FIG. 9 through the sliding portion between the first portion 131a of the plunger seal 13 and the plunger 2.

  In addition, since the tension force of the second portion 131b of the plunger seal 13 is relatively smaller than the tension force of the first portion 131a, the sub-chamber is against the sliding surface between the second portion 131b of the plunger seal 13 and the plunger 2. The fuel in 7a leaks slightly. The fuel leaked to the sliding surface between the plunger seal 13 and the plunger 2 lubricates and cools the sliding surface, thereby suppressing the generation of sliding frictional heat.

  According to the high-pressure fuel supply pump according to the second embodiment of the present invention described above, the same effect as that of the first embodiment described above can be obtained.

  Further, according to the present embodiment, the inner peripheral surface 79A of the first cylindrical portion 76A of the seal holder 7A is configured such that a step is formed by the first holding surface 79c and the second holding surface 79d. The processing of the inner circumferential surface 79A of the first cylindrical portion 76A is further facilitated.

  Next, a high-pressure fuel supply pump according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a cross-sectional view showing, in an enlarged state, a seal holder that constitutes a part of the high-pressure fuel supply pump according to the third embodiment of the present invention and the periphery thereof. FIG. 12 is a cross-sectional view showing the holding structure of the seal member of the seal holder shown in FIG. 11 in an enlarged state. In FIGS. 11 and 12, the same reference numerals as those shown in FIGS. 1 to 10 denote the same parts, so the detailed description thereof will be omitted.

  The third embodiment of the high pressure fuel supply pump according to the present invention shown in FIGS. 11 and 12 is different from the first embodiment in the first cylindrical portion of the inner cylindrical portion 71B of the seal holder 7B. It is the shape of the inner circumferential surface 79B of 76B. Specifically, the inner circumferential surface 79B of the first cylindrical portion 76B is formed of a second holding surface 79f formed of a cylindrical surface and a curved surface projecting radially inward of the second holding surface 79f. 1 and a holding surface 79e.

  In the plunger seal 13 and the seal holder 7B configured as described above, when the plunger seal 13 is press-fitted and held on the inner peripheral surface 79B of the first cylindrical portion 76B, the plunger seal 13 moves radially inward of the first holding surface 79e. Due to the deformation, the first portion 131a of the plunger seal 13 radially contracts more than the second portion 131b. In other words, the first pressing force F1 which presses the first portion 131a of the plunger seal 13 radially inward of the seal holder 7B presses the second portion 131b of the plunger seal 13 radially inward. Hold the plunger seal 13 so as to be larger than.

  Therefore, the tension on the plunger 2 of the first portion 131a of the plunger seal 13 is relatively larger than the tension on the second portion 131b. As a result, it is possible to prevent the lubricating oil on the engine side from flowing into the sub-chamber 7a shown in FIG. 11 via the sliding portion between the first portion 131a of the plunger seal 13 and the plunger 2.

  In addition, since the tension force of the second portion 131b of the plunger seal 13 is relatively smaller than the tension force of the first portion 131a, the sub-chamber is against the sliding surface between the second portion 131b of the plunger seal 13 and the plunger 2. The fuel in 7a leaks slightly. The fuel leaked to the sliding surface between the plunger seal 13 and the plunger 2 lubricates and cools the sliding surface, thereby suppressing the generation of sliding frictional heat.

  According to the high-pressure fuel supply pump of the third embodiment of the present invention described above, the same effect as that of the first embodiment described above can be obtained.

  The present invention is not limited to the present embodiment, but includes various modifications. The embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, and replace other configurations for part of the configurations of the respective embodiments.

  In the first to third embodiments of the high-pressure fuel supply pump according to the present invention described above, the plunger seal 13 has a shape of plane symmetry with respect to the bisecting plane P in the longitudinal direction (axial direction). Although the example which comprised it was shown, it is also possible to comprise so that it may become an asymmetrical shape with respect to the bisecting plane P of a length direction (axial direction). However, the shape of the plunger seal is set in such a range that the first pressing force F1 of the seal holder 7, 7A, 7B becomes larger than the second pressing force F2.

  In the first embodiment described above, the inner peripheral surface 79 of the first cylindrical portion 76 of the seal holder 7 is radially outward from the first holding surface 79a side to the second holding surface 79b side. Although the example which comprised the taper surface which expanded was shown, it is also possible to form so that the inner skin of the 1st cylindrical part may be expanded radially outward from the 1st holding surface side toward the 2nd holding surface side. is there. That is, the inner peripheral surface of the first cylindrical portion can be configured by a curved surface or the like other than the tapered surface. Also in the case of such a configuration, the same effect as that of the first embodiment can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Pump body, 2 ... plunger, 7, 7A, 7B ... seal holder, 7a ... subchamber, 11 ... pressurization chamber, 13 ... plunger seal (seal member), 16 ... pressing member (movement control member), 79, 79A, 79B: inner circumferential surface (holding inner circumferential surface) 79a, 79c, 79e: first holding surface 79b, 79d, 79f: second holding surface 131a: first portion 131b: second portion

Claims (7)

A pump body attached to an engine supplied with lubricating oil and having a pressure chamber therein;
A plunger that increases or decreases the volume of the pressure chamber by reciprocating movement;
A seal holder internally forming a sub-chamber capable of receiving fuel leaking from the pressure chamber along the plunger;
And a seal member held in the seal holder so as to be in sliding contact with the outer peripheral surface of the plunger, and sealing the sub chamber from the engine.
The seal holder presses a first portion on the engine side of the seal member radially inward. A first pressing force presses a second portion on the pressure chamber side of the seal member radially inward. A high-pressure fuel supply pump characterized in that the seal member is held so as to be larger than a pressing force. In the high pressure fuel supply pump according to claim 1,
Of the inner peripheral surface of the seal holder, the holding inner peripheral surface for holding the seal member is:
A first holding surface for holding the first portion of the seal member;
A high-pressure fuel supply pump comprising: a second holding surface for holding the second portion of the seal member and located radially outward of the first holding surface. In the high pressure fuel supply pump according to claim 2,
The high pressure fuel supply pump according to claim 1, wherein the holding inner circumferential surface is formed so as to expand radially outward from the first holding surface side toward the second holding surface side. In the high pressure fuel supply pump according to claim 3,
The high pressure fuel supply pump according to claim 1, wherein the inner circumferential surface is a tapered surface. In the high pressure fuel supply pump according to claim 2,
The high pressure fuel supply pump according to claim 1, wherein the holding inner circumferential surface has a step formed by the first holding surface and the second holding surface. In the high pressure fuel supply pump according to claim 2,
The second holding surface is formed of a cylindrical surface,
The high-pressure fuel supply pump according to claim 1, wherein the first holding surface is a curved surface projecting radially inward of the second holding surface. The high pressure fuel supply pump according to any one of claims 1 to 5, wherein
The high-pressure fuel further includes a movement restricting member which is held at a position closer to the pressurizing chamber than the seal member in the seal holder and restricts the movement of the seal member toward the pressurizing chamber. Supply pump.

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