JP2010112304A - Fuel supply pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply pump capable of preventing fuel leakage from a pressurizing chamber, by restraining a variation in contact pressure generated on an abutting surface between a valve body and a plunger barrel. <P>SOLUTION: This fuel supply pump is provided for pressurizing and forcibly feeding fuel in the pressurizing chamber by sucking the fuel in the pressurizing chamber via a fuel suction valve. The fuel suction valve has a valve piston having a seat part and the valve body having a sliding hole for slidingly holding the valve piston and a seat surface for seating the valve piston, and is fixed by pressing down the valve body by a valve body pressing member. The valve body pressing member has a space part opening on the side opposed to the valve body and a fuel passing hole for introducing the fuel to the space part, and the valve body or the valve piston has a fuel passage for introducing the fuel introduced to the space part to the pressurizing chamber side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel supply pump, and more particularly to a fuel supply pump that is used in an accumulator fuel supply system having a common rail and that pumps fuel at a pressure higher than that of a conventional rail to the common rail.

  Conventionally, as a device for supplying fuel to an internal combustion engine such as a diesel engine, a plurality of fuel injection valves are connected and a common rail for accumulating high-pressure fuel is provided. An accumulator fuel supply device (common rail system) that enables precise fuel injection control by supplying to the fuel tank is used.

  A fuel supply pump used in this accumulator fuel supply apparatus includes a fuel intake valve for sucking fuel into a pressurizing chamber whose volume changes by reciprocation of a plunger slidably supported in the cylinder. . An example of the configuration of the fuel supply pump including the fuel intake valve is shown in FIG. The fuel intake valve 320 of the fuel supply pump 300 includes a valve piston 335, a valve body 333 having a seat surface on which the valve piston 335 is seated and a sliding hole 336 that holds the valve piston 335 slidably, A spring seat 337 fixed in the vicinity of the end of the piston 335; and an urging means 341 that is sandwiched between the valve body 333 and the spring seat 337 and urges the valve piston 335 in the valve closing direction, and includes a screw plug 331. It is fixed by pressing the valve body 333 with the tightening force (see Patent Document 1).

Japanese Patent Laid-Open No. 2004-21580 (see FIG. 1 and FIG. 13)

In the fuel supply pump 300 having the fuel intake valve configured as shown in FIG. 8, the contact pressure between the valve body 333 and the plunger barrel 312 is generated by the tightening force of the screw plug 331 that fixes the valve body 333. Thus, fuel leakage from the pressurizing chamber 314 is prevented.
However, a fuel passage 350 is formed in the valve body 333 of the fuel intake valve 320 along a direction that intersects the direction in which the tightening force of the screw plug 331 acts. Therefore, the fuel passage 350 is distorted by the tightening force of the screw plug 331, and the surface pressure generated at the contact surface between the valve body 333 and the plunger barrel 312 corresponding to the fuel passage 350 is compared with the surface pressure in other regions. There was a risk that high pressure fuel would leak from the pressurizing chamber 314 to the low pressure side.

  As described above, when fuel leakage from the pressurizing chamber to the low pressure side occurs, there is a possibility that the compression efficiency of the fuel in the pressurizing chamber may be reduced or fretting wear may occur due to the passage of the high pressure fuel. Further, since the high pressure fuel becomes high temperature, the temperature of the fuel in the fuel supply pump gradually increases due to repeated leakage of the high pressure fuel to the low pressure side, and is also used as a lubricating oil for the sliding portion of the plunger. The viscosity of the fuel may decrease, and damage due to poor lubrication may occur.

Accordingly, the inventors of the present invention have made diligent efforts, and in the fuel intake valve provided in the fuel supply pump, a fuel passage formed in a direction intersecting the direction in which the force for pressing the valve body acts is formed from the valve body. The present invention has been completed by finding that such a problem can be solved by providing the valve body on the side of the member that presses the valve body away.
That is, an object of the present invention is to provide a fuel supply pump capable of preventing fuel leakage from the pressurizing chamber by suppressing variations in surface pressure generated on the contact surface between the valve body and the plunger barrel. .

  According to the present invention, a fuel supply pump for sucking fuel into a pressurizing chamber via a fuel suction valve, pressurizing and feeding the fuel in the pressurizing chamber, and the fuel suction valve has a seat portion. The valve body includes a valve piston, a valve body having a seat surface on which a seat portion of the valve piston is slidably held and a valve piston seat, and the valve body is pressed by a valve body pressing member. The valve body pressing member includes a space portion that opens to the side facing the valve body, and a fuel passage hole for introducing fuel into the space portion. A fuel supply pump is provided that includes a fuel passage that guides fuel introduced into the space to the pressurizing chamber side, and can solve the above-described problems. That.

  In configuring the fuel supply pump of the present invention, the fuel intake valve includes a spring seat fixed near the end of the valve piston on the side opposite to the seat, and both ends sandwiched by the valve body and the spring seat. Biasing means for biasing the piston in the valve closing direction, and the space of the valve body pressing member is preferably a space in which the spring seat and the biasing means are arranged.

  In configuring the fuel supply pump of the present invention, it is preferable that the fuel passage is provided facing the sliding hole of the valve body, and the fuel passage and the sliding hole constitute one opening.

  In configuring the fuel supply pump of the present invention, the valve body is preferably disposed at the opening of the plunger barrel and pressed by the valve body pressing member.

  In configuring the fuel supply pump of the present invention, the valve body pressing member has a plurality of fuel passage holes, and the biasing means on the spring seat in a state where the valve piston is seated on the seat surface of the valve body is locked. The fuel passage holes are preferably provided on both sides in the sliding direction of the valve piston.

  Further, in configuring the fuel supply pump of the present invention, it is preferable that the fuel intake valve is disposed on the side of the plunger in the axial direction.

  According to the fuel supply pump of the present invention, the fuel passage formed in the direction intersecting the direction in which the force for pressing the valve body acts is provided as the fuel passage hole of the valve body pressing member, and is not provided in the valve body. Therefore, it is possible to eliminate variations in the contact pressure between the valve body and the plunger barrel due to the distortion of the fuel passage of the valve body. Therefore, fuel leakage from the contact surface between the valve body and the plunger barrel is prevented to prevent deterioration of fuel compression efficiency and fretting wear in the pressurizing chamber, and poor lubrication due to fuel temperature rise in the fuel supply pump. Can be prevented.

  Further, in the fuel supply pump of the present invention, since the space portion of the valve body pressing member is a space in which the spring seat and the urging means are disposed, the shape of the valve body pressing member has not been greatly changed. A passage for the fuel flowing into the pressurizing chamber can be formed using the existing space.

  Further, in the fuel supply pump of the present invention, the fuel passage of the valve body is provided so as to face the sliding hole, so that the strength of the valve body is not lowered, while the outer shape of the valve body is increased. Can be prevented.

  Further, in the fuel supply pump of the present invention, the valve body is disposed at the opening of the plunger barrel and is pressed by the valve body pressing member, thereby facilitating the positioning of the valve body and the valve body and the plunger barrel. It is possible to improve the sealing performance.

  Further, in the fuel supply pump of the present invention, by providing a plurality of fuel passage holes at predetermined positions, when the valve piston moves in the direction in which the fuel intake valve closes, the low pressure fuel accumulates in the space portion, thereby It is possible to prevent the movement from being hindered and to make the fuel flow smoothly toward the fuel passage of the valve body through the space.

  Further, in the fuel supply pump of the present invention, the axial force acting on the cylinder on which the plunger slides can be reduced by arranging the fuel intake valve laterally with respect to the axial direction of the plunger. It is possible to provide a fuel supply pump that reduces stress acting on the cylinder inner surface and has excellent durability.

Hereinafter, embodiments of the fuel supply pump of the present invention will be described in detail with reference to the drawings. However, this embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.
In addition, what attached | subjected the same code | symbol in each figure has shown the same member, and description is abbreviate | omitted suitably.

1. 1 is a cross-sectional view of the fuel supply pump 1 according to the present embodiment cut along the arrangement direction of a plurality of plungers 13. This fuel supply pump 1 is used in a common rail system, and is a pump in which a cylinder 12a in which a plunger 13 for pressurizing fuel in a pressurizing chamber 14 is slidably disposed is disposed in parallel. The high-pressure pump unit 10 that pumps high-pressure fuel to the common rail 93 to which the fuel injection valve 95 of the internal combustion engine is connected, the low-pressure feed pump 3 that pumps the fuel in the fuel tank 91 to the high-pressure pump unit 10, and the high-pressure pump unit 10 A flow rate control valve 5 for adjusting the flow rate of the fuel to be sent is configured as a main element.
Each component is connected by a fuel passage, and the fuel in the fuel tank 91 is pressurized by the fuel supply pump 1 and pumped to the common rail 93, and is connected to the plurality of fuel injection valves 95 connected to the common rail 93. By supplying high-pressure fuel, fuel injection control to the internal combustion engine by energization control of the fuel injection valve 95 is performed.

  The low-pressure feed pump 3 has a gear pump structure including a drive gear (not shown) connected to the end of the camshaft 23 and a driven gear (not shown) connected to the drive gear. As the shaft 23 rotates, the fuel in the fuel tank 91 is sucked up by negative pressure and is pumped. Further, a prefilter (not shown) is interposed upstream of the low pressure feed pump 3, and when foreign matters are mixed in the fuel in the fuel tank 91, those foreign matters flow into the fuel supply pump 1. It is supposed to be collected so that there is no.

  The flow control valve 5 is configured using, for example, an electromagnetic proportional control valve, and is provided in a fuel passage between the low pressure feed pump 3 and the high pressure pump unit 10. The flow rate of the fuel fed into the pressurizing chamber 14 of the high-pressure pump unit 10 is adjusted by supplying a current having a magnitude corresponding to the fuel pressure required by the common rail system.

Although not shown, the fuel supply pump 1 includes an overflow valve that is branched from the middle of a fuel passage that communicates the low-pressure feed pump 3 and the flow control valve 5 and is arranged in parallel with the flow control valve 5. Yes. This overflow valve is connected to a fuel return passage 97 communicating with the fuel tank 91, and the pressure of the fuel sent to the flow control valve 5 exceeds a specified value or the pressure of the fuel sent to the flow control valve 5 When the difference between the pressure of the fuel in the fuel return path downstream from the overflow valve exceeds a predetermined range, the fuel is returned to the fuel tank 91 via the overflow valve.
At this time, the fuel recirculated through the overflow valve can be sent into a cam chamber 11b of the high-pressure pump unit 10 to be described later and used as lubricating oil. As a result, the fuel can be effectively used as the lubricating oil without using a separate lubricating oil or the like as the lubricating oil in the cam chamber.

Next, the configuration of the high-pressure pump unit 10 will be described in detail.
FIG. 2 shows a cross-sectional view of the XX cross-section of FIG. 1 as viewed in the direction of the arrow. As shown in FIG. 2, the high-pressure pump unit 10 of the fuel supply pump 1 of the present embodiment has a cam chamber 11 b in which a cam 21 is rotatably accommodated and a cylindrical space 11 a provided on the upper side of the cam 21. A pump housing 11 and a plunger barrel 12 mounted in the cylindrical space 11a are provided. A plunger 13 is slidably held in a cylinder 12 a provided inside the plunger barrel 12, and a spring seat 19 is locked to the end of the plunger 13. Also, in the cylindrical space 11a of the pump housing 11, a plunger spring 15 having both ends locked by a spring seat 19 and a plunger barrel 12 is disposed, and the plunger 13 is urged downward. ing.

Further, a tappet structure 18 having an inner peripheral surface of the cylindrical space 11a of the pump housing 11 and a slidable outer peripheral surface is interposed between the plunger 13 and the cam 21, and with the rotation of the cam 21, The plunger 13 is pushed upward while being centered against the urging force of the plunger spring 15.
The tappet structure 18 provided in the fuel supply pump 1 of the present embodiment includes a roller 17 and a tappet main body 16, and the roller main body 16 includes a roller holding portion 16 b that slides and holds the roller 17 and a cylindrical space. The sliding surface 16a with respect to 11a is provided. In addition to this, for example, a tappet without a roller can be used.

A fuel discharge valve 22 is disposed in the upper opening 61 of the cylinder 12 a of the plunger barrel 12, and a fuel intake valve 20 is disposed through a fuel suction path 12 b extending laterally from the cylinder 12 a of the plunger barrel 12. Has been.
A part of the cylinder 12 a of the plunger barrel 12 is defined by the plunger 13 and the fuel discharge valve 22 to form a pressurizing chamber 14. The fuel suction valve 20 is opened by the negative pressure generated when the plunger 13 is lowered, and low-pressure fuel is supplied to the pressurizing chamber 14 via the fuel suction passage 12b. When the fuel is closed, the fuel in the pressurizing chamber 14 is pressurized, and the fuel discharge valve 22 is opened, so that the fuel is pumped to the downstream common rail.

  The fuel discharge valve 22 disposed in the upper opening 61 of the cylinder 12 a of the plunger barrel 12 includes a delivery valve type valve body 51, a valve spring 53 that biases the valve body 51 in the valve closing direction, and a valve spring 53. A spring retainer 55 that holds the end opposite to the end engaged with the valve body 51 out of the end, and a plug holder 57 that holds the spring retainer 55 and is fixed to the plunger barrel 12 are provided. . In this way, the fuel discharge valve 22 mounted on the plunger barrel 12 is always closed with the seat portion 51 b of the valve body 51 seated on the seat surface 63 by the urging force of the valve spring 53. Then, when the pressure in the pressurizing chamber 14 increases and exceeds the sum of the urging force of the valve spring 53 and the pressure in the common rail, the valve body 51 is lifted and opened to increase the pressure. Fuel is supplied to the common rail.

2. Fuel Intake Valve Next, the configuration of the fuel intake valve 20 provided in the fuel supply pump 1 of the present embodiment will be described in detail with reference to FIGS. 3 and 4 (a) to 4 (b). FIG. 3 shows an enlarged cross-sectional view of the vicinity of the fuel intake valve 20 in the fuel supply pump 1 of the present embodiment shown in FIG. FIGS. 4A and 4B are views for explaining the configuration of the fuel intake valve 20 used in the fuel supply pump of the present embodiment. FIG. A perspective view is shown, and FIG. 4B shows a plan view of only the valve body 33 and the valve piston 35 as viewed from the upper side of FIG. 4A.

  The fuel intake valve 20 is a valve for supplying the fuel sent via the flow control valve to the pressurizing chamber 14, and is provided in the cylinder 12a of the plunger barrel 12 in the fuel supply pump of the present embodiment. The side of the pressurizing chamber 14 is disposed in a side opening 65 formed so as to communicate with the fuel suction passage 12b.

  The fuel intake valve 20 provided in the fuel supply pump of the present embodiment includes a valve piston 35 having a flange portion 35a on one end side, a valve body 33 that slidably holds the valve piston 35, and a valve piston 35. The spring seat 37 is fixed in the vicinity of the end opposite to the end provided with the collar portion 35a, and both ends are locked by the spring seat 37 and the valve body 33, and the valve piston 35 is attached in the valve closing direction. A valve spring 41 as a biasing means for biasing is provided as a main component.

The valve body 33 has a cylindrical outer shape and is provided with sliding holes 36 whose both ends are open along the axial direction. In the sliding hole 36 of the valve body 33, a flange portion 35a is provided on one end side, and the valve piston 35 is slidably held so that the flange portion 35a is disposed on the pressurizing chamber 14 side. Yes.
Further, a large-diameter recess 38 that is larger in diameter than the sliding hole 36 and concentrically formed with the sliding hole 36 is formed on the surface of the valve body 33 on the pressurizing chamber 14 side. The opening edge of the large-diameter recess 38 is a seat surface 38a on which the flange portion 35a of the valve piston 35 is seated. The depth (axial length) of the large-diameter recess 38 is set so that a space is formed in the large-diameter recess 38 when the valve piston 35 is seated.

A spring holding groove 39 that is concentrically formed with the sliding hole 36 and that presses one end of the valve spring 41 and defines the radial position of the valve spring 41 is provided on the surface of the valve body 33 on the screw plug 31 side. It has been.
The fuel intake valve 20 shown in FIGS. 3 and 4 (a) to 4 (b) is configured as a circular spring holding groove 39 that is entirely depressed with respect to the surface of the valve body 33 on the screw plug 31 side. However, as shown in FIGS. 5A to 5B, a donut-shaped spring holding groove 73 in which a protrusion 71 is formed around the central sliding hole 36 may be used. By providing the protrusion 71, when the valve spring 41 contracts, a spring seat 37, which will be described later, comes into contact, and the maximum stroke amount of the valve piston 35 is regulated. In FIG. 5A, the valve spring is omitted.

A fuel passage 50 formed along the axial direction of the valve body 33 is provided around the sliding hole 36 of the valve body 33 so as to face the sliding hole 36. 50, one opening is formed. The fuel passage 50 communicates the surface of the valve body 33 on the screw plug 31 side and the large-diameter recess 38 on the pressurizing chamber 14 side.
The fuel passage that communicates the surface of the valve body 33 on the screw plug 31 side and the large-diameter recess 38 on the pressurizing chamber 14 side can be provided in the valve piston 35 in addition to the valve body 33. In consideration of the flow path area and the strength of the valve piston 35, it is preferably provided in the valve body 33.

  As shown in FIG.4 (b), in the structural example of the fuel intake valve 20 of this embodiment, the three fuel passages 50a-50c are arrange | positioned at equal intervals. Although the number of the fuel passages 50 is not particularly limited, the fuel intake valve 20 of the present embodiment is composed of three fuel passages 50a to 50c, so the areas of the fuel passages 50a to 50c are compared. Even if the size of the fuel passages 50a to 50c is increased, the space between the fuel passages 50a to 50c is hardly thinned, the strength of the valve body 33 is ensured, and the sliding portion of the valve piston 35 is easily secured.

  In addition, the fuel passage is not provided independently of the sliding hole, but the fuel passages 50a to 50c and the sliding hole 36 form one opening as in the fuel intake valve 20 of the present embodiment. Since a thin portion is not formed between the sliding hole 36 and the strength is prevented from being lowered, the fuel is allowed to permeate the sliding portion between the valve piston 35 and the sliding hole 36. It becomes easy and lubricity is secured. Further, if the fuel passages 50a to 50c are configured to face the sliding holes, the diameter of the large-diameter concave portion 38 formed on the pressure chamber 14 side of the valve body 33 can be made as small as possible. In addition, the flange portion 35a of the valve piston 35 is made compact so that the fuel intake valve 20 is prevented from being enlarged.

  Further, the other end side of the valve spring 41 disposed in the spring holding groove 39 of the valve body 33 is locked by a spring seat 37 fixed to the side opposite to the flange portion 35 a side of the valve piston 35. Therefore, the valve spring 41 is sandwiched between the valve body 33 and the spring seat 37, and the valve piston 35 is urged in the direction in which the flange portion 35a of the valve piston 35 is seated on the seat surface 38a of the valve body 33, thereby A set load for valve opening is given to 35.

In the fuel intake valve 20 of the present embodiment, the valve body 33 is disposed in the side opening 65 of the plunger barrel 12 and is pressed toward the plunger barrel 12 by the tightening force of the screw plug 31. 12 side openings 65 are fixed.
The screw plug 31 has a small diameter portion 31a on the pressurizing chamber 14 side and a large diameter portion 31b on the opposite side of the pressurizing chamber 14, and a screw groove is formed on the outer peripheral surface of the large diameter portion 31b. 12 side openings 65 are screwed together. A space formed between the small diameter portion 31 a of the screw plug 31 and the inner peripheral surface of the side opening 65 of the plunger barrel 12 is provided as a fuel reservoir chamber 49.

  In addition, a space 43 that opens to the side facing the valve body 33 is provided in the small diameter portion 31 a of the screw plug 31, and the valve piston 33, the spring seat 37, and the valve spring 41 are disposed in the space 43. Has been. The small diameter portion 31 a of the screw plug 31 includes a plurality of fuel passage holes 45 that connect the space portion 43 and the fuel reservoir chamber 49. Among the plurality of fuel passage holes 45, some of the fuel passage holes 45a are formed closer to the valve body 33 than the spring locking portion 37a of the spring seat 37 when the valve piston 35 is in the seat position. The spring seat 37 makes it difficult for the fuel flow to be hindered. Further, another part of the fuel passage hole 45b is provided at a position opposite to the valve body 33 with respect to the spring locking portion 37a of the spring seat 37 in a state where the valve piston 35 is at the seat position. When the piston 35 returns from the lift position to the seat position, pressure is prevented from accumulating between the spring seat 37 and the space portion 43 so that the movement of the valve piston 35 is not hindered.

As described above, in the fuel intake valve 20 fixed by the screw plug 31, the low-pressure fuel that is pumped by the low-pressure feed pump and flows through the low-pressure fuel passage formed in the pump housing and the plunger barrel is moved into the fuel reservoir chamber 49. And flows into the space 43 in the screw plug 31 through a plurality of fuel passage holes 45 formed in the small diameter portion 31 a of the screw plug 31. Further, the low-pressure fuel that has flowed into the space 43 flows into the fuel passage 50 formed in the valve body 33, and the pressure in the space 43 and the fuel passage 50 is increased. When a negative pressure is generated in the fuel suction passage 12b as the plunger 13 is lowered, the sum of the pressure in the space 43 and the fuel passage 50 and the negative pressure in the fuel suction passage 12b is the biasing force of the valve spring 41. As a result, the valve piston 35 is lifted to supply low pressure fuel to the pressurizing chamber 14 side.
Thereafter, as the pressure of the fuel in the pressurizing chamber 14 increases with the rise of the plunger, the valve piston 35 is seated on the valve body 33 again, thereby stopping the supply of fuel.

Here, as described above, the fuel intake valve 20 of the present embodiment is fixed in the side opening 65 of the plunger barrel 12 by pressing the valve body 33 with the tightening force of the screw plug 31. At this time, the contact surface S on which the valve body 33 and the plunger barrel 12 abut must secure a sealing property so that the high-pressure fuel pressurized in the pressurizing chamber 14 does not leak out. The tightening force of 31 is relatively large, and the surface pressure is increased.
In the configuration of the fuel intake valve 20 of the present embodiment, only the fuel passage 50 in the axial direction is formed in the valve body 33 and no fuel passage extending in the circumferential direction is provided. The surface pressure of the contact surface S between the valve body 33 and the plunger barrel 12 is uniformly generated by the tightening force, and fuel leakage from the contact surface S is prevented.

  More specifically, as shown in FIG. 6A, in the conventional fuel intake valve 120 in which the fuel passage hole 150 extending in the circumferential direction is formed in the valve body 133, the tightening force by the screw plug 131 is low. When acting on the valve body 133, the fuel passage hole 150 arranged to intersect the direction in which the tightening force acts is distorted. Then, as shown in FIG. 6B, the surface pressure in the region corresponding to the position of the fuel passage hole 150 in the contact surface S between the valve body 133 and the plunger barrel 112 decreases, and the fuel is likely to leak. There is a fear. In particular, in the case of a fuel supply pump configured to pressurize at a higher pressure than before, high-pressure fuel is likely to leak out from a region where the surface pressure has decreased.

  On the other hand, in the fuel intake valve 20 of this embodiment, the fuel in the fuel reservoir chamber 49 flows along the axial direction of the valve body 33 while flowing into the space 43 through the fuel passage hole 45 of the screw plug 31. The pressurizing chamber 14 is supplied through the formed fuel passage 50. Therefore, as shown in FIG. 7, the fuel passage hole formed along the circumferential direction of the valve body 33 is omitted, and the surface pressure generated on the contact surface S between the valve body 33 and the plunger barrel 12 is made uniform. . As a result, fuel leakage from the contact surface S between the valve body 33 and the plunger barrel 12 is prevented, and it is not necessary to consider variations in surface pressure, so that the tightening force of the screw plug 31 can be increased. It becomes like this.

As described above, according to the fuel supply pump of the present embodiment, the fuel passage hole disposed along the direction intersecting the tightening force from the valve body 33 of the fuel intake valve 20 fixed by the tightening force of the screw plug 31. Is omitted, and the surface pressure generated on the contact surface S between the valve body 33 and the plunger barrel 12 can be made uniform. Therefore, the sealing performance between the valve body 33 and the plunger barrel 12 is improved, and fuel leakage from the pressurizing chamber 14 side can be effectively prevented.
As a result, it is possible to suppress a reduction in fuel compression efficiency and fretting wear due to leakage of high-pressure fuel, and further occurrence of poor lubrication due to an increase in fuel temperature in the low-pressure fuel system.

  Further, as shown in FIG. 2, in the fuel supply pump 1 of the present embodiment, the fuel intake valve 20 is disposed on the side of the axial direction of the cylinder 12a through the fuel intake passage 12b, and the screw plug 31 The tightening force is prevented from acting in the axial direction of the cylinder 12a. Therefore, even when the tightening force of the screw plug 31 is large, it does not act as an axial force on the cylinder 12a, and the stress generated on the inner periphery of the cylinder 12a is reduced, so that the fuel supply pump 1 is improved in durability.

It is a transverse cross section for explaining an example of composition of a fuel supply pump concerning an embodiment of the invention. It is a longitudinal cross-sectional view for demonstrating the structural example of a fuel supply pump. It is sectional drawing for demonstrating the structural example of a fuel intake valve. It is the perspective view and top view for demonstrating the structural example of a fuel intake valve. It is the perspective view and sectional drawing for demonstrating another structural example of a fuel intake valve. It is a figure for demonstrating the surface pressure which arises when using the fuel intake valve in which the fuel passage hole was formed in the valve body. It is a figure for demonstrating the surface pressure which arises when using the fuel intake valve of this embodiment. It is a figure for demonstrating the structure of the conventional fuel supply pump.

Explanation of symbols

1: fuel supply pump, 3: low pressure feed pump, 5: flow control valve, 10: high pressure pump section, 11: pump housing, 11a: cylindrical space, 11b: cam chamber, 12: plunger barrel, 12a: cylinder, 12b: Fuel intake path, 13: Plunger, 14: Pressurizing chamber, 15: Plunger spring, 16: Tappet body, 16a: Sliding surface, 16b: Roller holding part, 17: Roller, 18: Tappet structure, 19: Spring Seat: 21: Cam, 20: Fuel intake valve, 22: Fuel discharge valve, 23: Cam shaft, 31: Screw plug, 33: Valve body, 35: Valve piston, 35a: Collar portion, 36: Sliding hole, 37 : Spring seat, 37a: Spring locking part, 38: Large diameter recess, 38a: Seat surface, 39: Spring holding groove, 41: Valves Ring, 43: space, 45: fuel passage hole, 49: fuel reservoir, 51: valve body, 51b: seat, 53: valve spring, 55: spring retainer, 57: plug holder, 61: upper opening 63: Seat surface, 65: Side opening, 91: Fuel tank, 93: Common rail, 95: Fuel injection valve

Claims (6)

In a fuel supply pump for sucking fuel into a pressurizing chamber via a fuel intake valve, pressurizing and feeding fuel in the pressurizing chamber,
The fuel intake valve includes a valve piston having a seat portion, a valve body including a sliding hole for slidably holding the valve piston and a seat surface on which the valve piston is seated, and a valve body It is fixed by pressing the valve body with a pressing member,
The valve body pressing member includes a space portion that opens to the side facing the valve body, and a fuel passage hole for introducing the fuel into the space portion,
The valve body or the valve piston includes a fuel passage that guides the fuel introduced into the space to the pressurizing chamber side. The fuel intake valve includes a spring seat fixed near the end of the valve piston opposite to the seat portion, and both ends sandwiched between the valve body and the spring seat, and attaches the valve piston in the valve closing direction. An urging means for energizing,
2. The fuel supply pump according to claim 1, wherein the space portion of the valve body pressing member is a space in which the spring seat and the urging means are arranged.   The fuel supply pump according to claim 1 or 2, wherein the fuel passage is provided facing the sliding hole of the valve body, and the fuel passage and the sliding hole constitute one opening. .   The fuel supply pump according to any one of claims 1 to 3, wherein the valve body is disposed at an opening of a plunger barrel and is pressed by the valve body pressing member.   The valve body pressing member includes a plurality of the fuel passage holes, and the position where the urging means in the spring seat is locked in a state where the valve piston is seated on the seat surface of the valve body as a reference. The fuel supply pump according to any one of claims 2 to 4, wherein the fuel passage holes are provided on both sides in the sliding direction of the valve piston.   The fuel supply pump according to any one of claims 1 to 5, wherein the fuel intake valve is disposed laterally with respect to an axial direction of the plunger.

Images