WO2007129556A1 - Fuel feeding pump - Google Patents

Abstract

A fuel feeding pump where a fuel suction valve has enhanced durability and capable of stably feeding under pressure a high-pressure high-flow rate fuel. In the fuel suction valve, a valve piston has a groove in the outer surface near an end section on the opposite side of a flange, and a stopper for fixing the valve piston and a spring seat is engaged with the groove. The spring seat has an opening in which the valve piston is inserted and a step that is along an edge of the opening and to which the stopper is engaged. After the valve piston is inserted into the opening of the spring seat, the stopper is engaged with the groove of the valve piston, the spring seat is urged by a spring to engage the stopper to the step, and, as a result, the spring seat is fixed to the valve piston. A gap is provided between the stopper and at least either that edge of the groove which is on the side of the urging direction by the spring or that edge of the step which is on the opposite side of the urging direction.

Description

 Specification

 Fuel supply pump

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a fuel supply pump provided with a fuel intake valve, and more particularly to a fuel supply pump suitable for pumping a high flow rate high-pressure fuel.

 [0002] Conventionally, various types of accumulator fuel injection devices (CRS: Common Rail System) using accumulators (common rails) have been proposed in order to efficiently inject high-pressure fuel in diesel engines and the like. .

 An example of a fuel supply pump used in such an accumulator fuel injection system is shown in FIG. The fuel supply pump 410 is provided with a cam 429 in the pump housing 421, and has a cylindrical space 421a in which a plunger barrel 415 is mounted above the cam 429, and the plunger barrel 415 mounted in the cylindrical space 421a. A fuel intake valve 422 is attached to the upper opening of the. In addition, a fuel pressurization chamber 425 closed by a plunger 423 and a fuel intake valve 422 is formed inside the plunger barrel 415, and further, a fuel discharge valve 428 is provided at a portion facing the fuel pressurization chamber 425. A connecting fuel passage 431 is provided. In the fuel supply pump 410, the fuel discharge valve is pressurized after being pressurized by the plunger 423 that reciprocates as the fuel cam 429 rotates through the fuel suction chamber 425 via the fuel intake valve 422. It is pumped to the common rail via 428.

Here, a fuel intake valve 422 used in a fuel supply pump has a valve body 433 and a valve piston 435 having a flange 436 at one end and slidably held by the valve body 433. And a spring 441 that urges the valve piston 435 in the valve closing direction, and a spring that receives one end of the spring 441 and is fixed near the end of the valve piston 435 opposite to the end where the flange 436 is provided. And a sheet 437 (see Patent Document 1). In the fuel intake valve 422, fuel is supplied to the fuel reservoir 433a through the fuel intake hole, and the difference between the pressure in the fuel pressurization chamber 425 and the pressure in the fuel reservoir 433a is a predetermined pressure value. When the pressure exceeds the value, the fuel is opened and fuel is supplied into the fuel pressurizing chamber 425. On the other hand, as the plunger 423 rises, the pressure in the fuel pressurizing chamber 425 increases, and the pressure in the fuel reservoir 433a decreases, so that the valve piston 435 moves to the seat portion of the valve body 433. The seat is closed.

 Patent Document 1: Japanese Patent Application Laid-Open No. 2004-211580 (Figs. 1 and 13)

 Disclosure of the invention

 Problems to be solved by the invention

However, in the fuel intake valve used in the fuel supply pump disclosed in Patent Document 1, the valve piston and the spring seat are configured separately from each other for assembly reasons. Since this fuel intake valve is generally about 3 to 4 cm in size, laser welding is adopted as a simple fixing method when fixing the nozzle piston and spring seat. . Therefore, it is necessary to select a material that can be easily welded as a material for the valve piston, and it has been difficult to adopt a material having a relatively high strength such as high carbon steel. As a result, there is a risk that the portion of the valve piston seated on the valve body will be worn out and the durability will soon be poor. In particular, when a veg fuel supply pump that pumps a large amount of high-pressure fuel, such as an accumulator fuel injection device, is rotated at high speed, the durability of the valve piston decreases excessively and is stable. In some cases, pressure treatment could not be performed.

 [0005] Therefore, as a result of intensive studies, the inventors of the present invention have adopted a mechanical fixing method using a predetermined stopper instead of welding as a fixing method of the valve piston and the spring seat, and the valve piston and the spring seat. Alternatively, it has been found that such a problem can be solved by providing a predetermined structure in the spring seat where the stopper is locked.

 That is, the present invention provides a fuel supply device that is improved in durability, in which the fuel intake valve is difficult to be damaged even when the fuel supply pump is driven at high speed to pump a high flow rate of high pressure fuel. The object is to provide a pump.

 Means for solving the problem

[0006] According to the present invention, there is provided a fuel supply pump comprising a fuel pressurization chamber for increasing the pressure of fuel and a fuel intake valve for supplying fuel to the fuel pressurization chamber, The fuel intake valve includes a valve body, a valve piston having a flange portion on one end side and held slidably on the valve body, a spring for urging the valve piston in the valve closing direction, and one end side of the valve piston. Fixed near the end opposite to the end of the spring. The valve piston has a groove portion on the outer surface near the end on the opposite side, in which a stopper for fixing the valve piston and the spring seat is locked, and the spring seat It has an opening into which the piston is inserted, and has a step portion to which the stopper is locked along the edge of the opening. After inserting the valve piston into the opening of the spring seat, the stopper is inserted into the valve. The spring seat is fixed to the valve piston by engaging the spring seat with the spring and engaging the stopper with the step by engaging the spring seat with the groove of the piston. A fuel supply pump is provided in which a gap is provided between at least one of the edges of the edge or step opposite to the biasing direction and the stopper. It is possible to solve the above problem.

 [0007] Further, in configuring the fuel supply pump of the present invention, the cross-sectional shape of the groove portion or the step portion is an arc shape, and the gap is formed by shifting the center of the circle drawing the arc to the outer surface position force of the valve piston. It is preferable to provide it.

 Hereinafter, in this specification, “the outer surface position of the valve piston” is present when it is assumed that the surface position on the outer side in the circumferential direction with respect to the axis of the valve piston and the surface position on the outer side in the circumferential direction extend. Means the surface position.

In configuring the fuel supply pump of the present invention, it is preferable that a frictional force generating member is interposed between the groove or step and the stopper.

[0009] Further, in configuring the fuel supply pump of the present invention, it is preferable that the stopper is a C-ring having a high elasticity and an alloying force.

[0010] In configuring the fuel supply pump of the present invention, it is preferable that the valve piston and the spring seat be carburized material or bearing steel force.

[0011] Further, another aspect of the present invention is a fuel supply pump including a fuel pressurization chamber for increasing the pressure of the fuel, and a fuel intake valve for supplying fuel to the fuel pressurization chamber. The fuel intake valve includes a valve body, a valve piston having a flange portion at one end and slidably held by the valve body, a spring that urges the valve piston in a valve closing direction, and the valve piston. A spring seat that is fixed near the end opposite to the one end side and receives one end of the spring, and the valve piston has the valve piston and the spring seat on the outer surface near the opposite end. Groove where the stopper for fixing is locked The spring seat has an opening into which the nozzle piston is inserted, and has a step portion with which a stopper is locked along the edge of the opening, and a valve is provided at the opening of the spring seat. After inserting the piston, the spring seat is fixed to the valve piston by locking the stopper to the groove of the valve piston and urging the spring seat by the spring to lock the stopper to the stepped portion. In this fuel supply pump, the contact portion between the groove portion and the stopper and the contact portion between the step portion and the stopper are connected obliquely with respect to the urging direction.

 The invention's effect

 [0012] According to the fuel supply pump of the present invention, the valve piston and the spring seat are fixed by a mechanical fixing method using a predetermined stopper, so that the selection of the material constituting the valve piston is free. The degree of spread increases, and it becomes possible to select high-strength materials that are unsuitable for welding. Therefore, the strength of the valve piston can be increased, and wear of the seated portion with respect to the valve body can be reduced.

 In addition, if the stopper is in a predetermined contact state with at least one of the groove part of the valve piston or the step of the spring seat to which the stopper is locked, the pressing force of the valve piston by the fuel pressure or the application of the spring It is possible to prevent the stopper from being damaged by preventing the shearing force from acting on the stopper due to a force or the like.

 Accordingly, since the durability of the fuel intake valve is improved, a high flow rate of high-pressure fuel can be stably pumped even when the pump is rotated at a high speed.

 Brief Description of Drawings

 FIG. 1 is a side view including a partial cutout of a fuel supply pump according to an embodiment of the present invention.

 FIG. 2 is a cross-sectional view of a fuel supply pump according to an embodiment of the present invention.

 FIG. 3 is a cross-sectional view of a fuel intake valve provided in a fuel supply pump.

 FIG. 4 is a diagram for explaining parts constituting a fuel intake valve.

 FIG. 5 is a diagram for explaining a method of assembling a fuel intake valve.

 FIG. 6 is a diagram for explaining the direction of the force acting on the stopper.

FIG. 7 is a diagram for explaining another configuration example of the fuel intake valve. FIG. 8 is a view for explaining a groove portion of a valve piston having a circular cross section and a step portion of a spring seat.

 FIG. 9 is a view for explaining a groove portion of a valve piston having a straight cross section and a step portion of a spring seat.

 FIG. 10 is a diagram for explaining the configuration of a fuel intake valve with a frictional force generating member interposed.

 FIG. 11 is a diagram for explaining an accumulator fuel injection system (APCRS) using a piston boosting system.

 FIG. 12 is a diagram conceptually showing a method for boosting fuel using a piston pressure-accumulating fuel injection system (APCRS).

 FIG. 13 is a diagram for explaining the structure of a conventional fuel supply pump.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the fuel supply pump according to the present invention will be specifically described with reference to the drawings. However, the embodiment to be described shows one aspect of the present invention, and can be arbitrarily changed within the scope of the present invention which is not intended to limit the present invention.

 In addition, in each figure, what attached | subjected the same code | symbol has shown the same member, and abbreviate | omits description suitably.

 [0015] An embodiment of the present invention is a fuel supply pump including a fuel pressurization chamber for increasing the pressure of fuel and a fuel intake valve for supplying fuel to the fuel pressurization chamber.

In the fuel supply pump according to the present embodiment, the fuel intake valve has a valve body, a valve piston having a flange portion at one end side, and slidably held by the valve body, and the valve piston in the valve closing direction. A spring for biasing, and a spring seat that is fixed near the end of the valve piston opposite to the end provided with the flange, and receives one end of the spring, and the valve piston has an end on the opposite side On the outer surface in the vicinity, there is a groove portion to which a stopper for fixing the nozzle piston and the spring seat is engaged. The spring seat has an opening portion into which the valve piston is inserted, and the opening portion of the opening portion. Along the edge is a step where the stopper is locked, and a nore piston is installed in the opening of the spring seat. After insertion, the spring seat is fixed to the valve piston by locking the stopper to the groove of the valve piston and urging the spring seat by the spring to lock the stopper to the stepped portion. A gap is provided between at least one of the edge portion on the urging direction side or the edge portion on the opposite side of the urging direction at the step portion and the stopper.

 Hereinafter, the fuel supply pump according to the present embodiment will be specifically described separately for each member.

 [0016] 1. Overall configuration

 The overall configuration of the fuel supply pump of the present invention is not particularly limited, but an example is shown in FIG. This fuel supply pump 1 is a so-called column type pump in which cylinders (column space) 11 lb, 11c in which a plunger 13 for pressurizing fuel is arranged are arranged in parallel, and a pump main body that pumps fuel at a high pressure A part 10, a feed pump 3 for pumping fuel from a fuel tank (not shown), and a metering valve 5 for adjusting the flow rate of the pressurized fuel are provided.

 The example of the fuel supply pump 1 is configured to increase the pressure of the fuel by using two plungers 13 and to pump the fuel. However, in order to process a larger volume of fuel at a higher pressure, the fuel supply pump 1 is increased to a higher number. You can also

[0017] 2. Feed pump

 The feed pump 3 is a part for pumping up the fuel in the fuel tank and transferring it to the metering valve 5. The feed pump 3 has a gear pump structural force including, for example, a drive gear connected to the end of the camshaft 23 and a driven gear connected to the drive gear, and is directly connected to the camshaft 23 or via an appropriate gear ratio. Driven. When the feed pump 3 is driven, fuel is sucked up from the fuel tank and transferred to the metering valve 5 using negative pressure.

 In addition, a pre-filter (not shown) is interposed between the feed pump 3 and the fuel tank, and when foreign objects are mixed in the fuel in the fuel tank, these foreign objects are transferred to the fuel supply pump 1 It can be collected primarily so that it does not flow into.

[0018] 3. Metering valve The metering valve 5 is attached to the pump body 10 and is a part for adjusting the fuel amount when the fuel transferred from the feed pump 3 is transferred to the fuel pressurizing chamber 14 of the pump body 10. It is. The metering valve 5 can be configured using, for example, a proportional control valve. With this metering valve 5, the fuel amount can be adjusted in accordance with the fuel pressure required by the internal combustion engine and can be fed into the fuel pressurizing chamber 14 of the pump body 10.

[0019] 4. Overflow Banorebu

 In addition, although not shown, the fuel supply pump includes an overflow valve that branches from the middle of the fuel passage that connects the feed pump and the metering valve and is arranged in parallel with the metering valve. When the pressure of the fuel transferred to the metering valve exceeds the specified value or the flow rate of the fuel transferred to the metering valve exceeds the specified amount, the fuel flows through the overflow valve. It can be refluxed to a tank or the like. At this time, the fuel that has flowed to the overflow valve side can be transferred to a cam chamber of a pump body, which will be described later, and used as lubricating oil. As a result, it is possible to effectively use fuel that does not separately supply lubricating oil or the like as lubricating oil in the cam chamber, and it is possible to prevent the entire fuel supply pump from being enlarged and complicated.

[0020] 5. Pump body

 (1) Basic configuration

 The pump body 10 is a part for increasing the pressure of the fuel transferred through the metering valve 5 and pumping it to the downstream common rail or the like.

Here, FIG. 2 shows a cross-sectional view of the fuel supply pump 1 of FIG. As shown in FIG. 2, the pump body 10 is slid into, for example, a pump housing 11, a plunger barrel 12 mounted in a cylindrical space l ib of the pump housing 11, and an internal space 12a of the plunger barrel 12. A plunger 13 that is moved and held, a springer sheet 19 that is locked to the end of the plunger 13, and a spring that is locked at both ends by the plunger barrel 12 and the spring seat 19 and biases the plunger 13 downward. 15 and a tappet structure 18 that is interposed between the plunger 13 and the cam 21 and pushes up the plunger 13 while centering it as the cam 21 rotates. A fuel intake valve 20 is disposed in the upper opening of the internal space 12a of the plunger barrel 12 and the plunger barrel 12 A fuel discharge valve 22 is disposed through a fuel passage 12b extending in the lateral direction from the partial space 12a.

 A part of the inner space 12 a of the plunger barrel 12 forms a fuel pressurizing chamber 14 that is closed by the inner peripheral surface of the plunger barrel 12, the plunger 13, and the fuel intake valve 20. Then, the fuel supplied through the fuel intake valve 20 is increased in pressure in the fuel pressurizing chamber 14 by the plunger 13 that is pushed up by the rotational movement of the cam 21, and downstream via the fuel discharge valve 22. It is pumped to the common rail.

[0022] (2) Pump housing

 The pump housing 11 is a housing in which the plunger barrel 12 is mounted and the plunger 13, the tappet structure 18, the cam 21 and the like are accommodated. The pump housing 11 can be configured to include, for example, a cam chamber 11a and a cylindrical space l ib that opens above the cam chamber 11a and to which the plunger barrel 12 is mounted.

 The form of the pump housing including the number of cylindrical spaces can be changed as appropriate in accordance with the type of fuel supply pump.

[0023] (3) Plunger barrel

 The plunger barrel 12 is attached to the cylindrical space l ib of the pump housing 11 and is a housing in which the plunger 13 is slidably held in the internal space 12a and the fuel intake valve 20 is disposed in the upper opening of the internal space 12a. is there. The internal space 12 a of the plunger barrel 12 is an element that constitutes the fuel pressurizing chamber 14 for increasing the pressure of the fuel together with the plunger 13 and the fuel intake valve 20.

 When the fuel supply pump type is an in-line type or a radial type, the form of the plunger barrel can be changed as appropriate in accordance with the type.

[0024] (4) Plunger

The plunger 13 is a portion that is slidably held in the internal space 12 a of the plunger barrel 12 and is pushed up as the cam 21 rotates to increase the pressure of the fuel in the fuel pressurizing chamber 14. A spring seat 19 is received at the end of the plunger 13 to receive one end of the spring 15 and pull down the plunger 13 toward the cam 21 by the urging force of the spring 15. The The plunger 13 is held up and down by a downward force due to the urging force of the spring 15 and an upward force accompanying the rotation of the cam 21.

 [0025] (5) Fuel pressurizing chamber

 The fuel pressurizing chamber 14 is a small chamber formed by being closed by the plunger 13 and the fuel intake valve 20 in the internal space 12a in the plunger barrel 12. In this fuel pressurizing chamber 14, the fuel that has flowed in through the fuel intake valve 20 can be efficiently and massively pressurized by the plunger 13 being driven at a high speed. The fuel pressurized by the plunger 13 is supplied to a common rail or the like via a fuel discharge valve 22.

 [0026] (6) Cam

 The cam 21 includes one or a plurality of cam ridges, and is a main element for raising the plunger 13 via the tappet structure 18 as the cam shaft 23 rotates. The powerful cam 21 is fixedly attached to a camshaft 23 connected to the diesel engine in the cam chamber 11a. The camshaft 23 is connected to the crankshaft of the engine via a gear, and the cam 21 is configured to rotate by driving the engine. The cam 21 is positioned below the cylindrical space l ib of the pump housing 11 and is arranged in parallel at a predetermined interval in the axial direction of the cam shaft 23.

[0027] (7) Tappet structure

 The tappet structure 18 is interposed between the plunger 13 and the cam 21, and is used to move the plunger 13 up and down while centering the plunger 13 in response to the rotation of the cam 21 as the cam shaft 23 rotates. It is a member. The structure of the powerful tappet structure 18 is not particularly limited. For example, the tappet structure 18 shown in FIG. 2 includes a spring sheet 19, a tappet main body portion 16 including a roller holding portion 16b and a sliding portion 16a. And roller 17 and force are also configured. In addition, for example, a tappet that does not include a roller can be used.

[0028] (8) Fuel intake valve

 The fuel intake valve 20 is disposed at an upper opening portion of an internal space 12 a provided in the plunger barrel 12 and is a part for supplying the fuel transferred through the metering valve to the fuel pressurizing chamber 14.

In the vicinity of the fuel intake valve 20 in the fuel supply pump 1 of the present embodiment (the part indicated by A in FIG. 2) Fig. 3 (a) shows an enlarged cross-sectional view of Fig. 3 (a), and Fig. 3 (b) shows an enlarged cross-sectional view of the portion indicated by B in Fig. 3 (a).

 The fuel intake valve 20 shown in FIG. 3 (a) includes a holder portion 31, a nozzle body 33, a flange portion 35a on one end side, a valve piston 35 slidably held by the valve body 33, and a valve A spring seat 37 that biases the piston 35 in the valve closing direction, and a spring seat 37 that is fixed near the end of the valve piston 35 opposite to the end provided with the flange 35a and receives one end of the spring 41 And. In addition, a seal ring groove 45 is provided on the outer peripheral surface of the holder part 31, and a seal property between the holder part 31 and the pump housing 11 is ensured by the seal ring 43 disposed in the seal ring groove 45. ing. In addition, the space 31a of the holder 31 is filled with fuel as a lubricating oil for ensuring the lubricity of the sliding surface of the valve piston 35, and the plug 47 is press-fitted in the upward force of the space 31a. And contain the fuel for lubrication. Further, a gap 49 as a passage for fuel flowing into the suction passage 33b of the valve body 33 is provided between the valve body 33 and the pump housing 11 in the outer peripheral direction of the valve body 33 (lateral direction in the figure). ing. This gap 49 enables the fuel to be sucked from the suction passages 33b provided radially in the valve body 33.

In the powerful fuel intake valve 20, the valve piston 35 is always urged by the spring 41 in the valve closing direction. Then, the fuel transferred through the metering valve flows into the fuel reservoir chamber 33a through the gap 49 and the radially formed suction passage 33b, and the pressure in the fuel pressurizing chamber 14 and the fuel reservoir chamber 33a When the pressure difference exceeds a predetermined pressure value, the valve is opened and fuel is supplied into the fuel pressurizing chamber 14. Thereafter, when the pressure in the fuel reservoir chamber 33a decreases and the fuel in the fuel caloric pressure chamber 14 rises as the plunger 13 rises in the fuel pressurizing chamber 14, the fuel intake valve 20 is driven by the urging force of the spring 41. Is closed again.

 At this time, the fuel in the fuel reservoir chamber 33a of the valve body 33 or the space portion 31a of the holder portion 31 enters the sliding surface of the valve piston 35 slidably held by the valve body 33, and lubricity is ensured. Prevents burn-in.

Here, the fuel intake valve in the fuel supply pump of the present invention is as shown in FIG. The valve piston 35 has a groove portion 51 in which a stopper 40 for fixing the valve piston 35 and the spring seat 37 is locked to a circumferential outer surface near the end opposite to the flange portion, and a spring. The seat 37 has an opening 37a into which the valve piston 35 is inserted or press-fitted, and has a step 53 to which the stopper 40 is locked along the edge of the opening 37a. After inserting or press-fitting the valve piston 35 into the opening 37a of 37, the stopper 40 is locked to the groove 51 of the valve piston 35, and the spring seat 37 is urged by the spring 41 and stopped to the step 53. The spring seat 37 is fixed to the valve piston 35 by locking the tool 40, and the edge 51a on the biasing direction side in the groove 51 or the edge 53a on the opposite side to the biasing direction in the step 53 is provided. At least of A gap S is provided between one end and the fastener 40.

 More specifically, as shown in FIG. 13, the conventional fuel intake valve is fixed to the valve piston 435 and the spring seat 437 by laser welding! As the material, carburized material, bearing steel, etc., which has low bonding strength by welding, could not be used. Therefore, as the pump with relatively low wear resistance of the valve piston 435 is rotated at high speed or the fuel pressure becomes high, the portion of the valve body 433 that comes into contact with the seat is damaged and is easily durable. There was a fear of being poor. Further, a carburized material or the like cannot be used for the spring seat 437, and a high hardness shim (not shown) has to be interposed in order to protect the receiving surface of the spring 441 from damage.

 Therefore, as shown in FIG. 3 (b), the fuel intake valve used in the fuel supply pump of the present invention has a predetermined method for fixing the valve piston 35 and the spring seat 37 in the fuel intake valve 20. The fixing method using the stopper 40 is adopted. Therefore, the carburizing material is hardly deformed, such as bearing steel, and the noble piston 35 and the spring seat 37 can be configured using the material. As a result, the strength of the valve piston 35 is increased, and the fuel can be stably pumped even when the pump is rotated at high speed or the fuel pressure becomes high. In addition, the strength of the spring seat 37 is enhanced, and one end of the spring 41 can be directly received by the spring seat 37. Therefore, it is necessary to interpose a shim or the like, and the number of parts can be reduced.

[0033] The fuel intake valve 20 shown in FIGS. 3 (a) to 3 (b) includes spring springs shown in FIGS. This is assembled using a 37, C-ring 40A as a stopper 40, a Noreb body 33, and a Noreb piston 35.

 That is, first, as shown in FIG. 5A, the valve piston 35 is inserted into the valve body 33 and the spring 41 is disposed on the upper surface of the valve body 33. Next, as shown in FIG. 5B, the valve piston 35 is inserted or press-fitted into the opening 37a of the spring seat 37, and the spring 41 is contracted by being pressed as it is. In this state, as shown in FIG. 5 (c), after the C-ring 40A is locked to the groove 51 of the valve piston 35, the spring seat 37 is urged by the spring 41 as shown in FIG. Then, the C-ring 40A is locked to the step 53 of the spring seat 37. Thus assembled, the spring seat 37 is fixed to the valve piston 35.

[0034] However, if a forceful fixing method is adopted, the spring biasing force, the force of pushing down the valve piston due to the fuel pressure in the fuel reservoir chamber, and the force press the spring seat and the valve piston in opposite directions. The stoppers respectively engaged with the piston groove and the spring seat step are easily subjected to the shearing force caused by the valve piston groove edge and the spring seat step edge.

 Therefore, in the present invention, as shown in FIG. 3 (b), the edge 51a of the spring 41 in the groove 51 of the valve piston 35 (on the side opposite to the flange of the valve piston 35) 51a or spring By providing a gap S between at least one of the edge portions 53a of the step portion 53 of the seat 37 opposite to the biasing direction of the spring 41 (the flange portion side of the valve piston 35) and the stopper 40 The shearing force acting on the stopper 40 is reduced to prevent the stopper 40 from being damaged.

 In other words, the contact portion P1 between the groove 51 of the valve piston 35 and the stopper 40 and the contact portion P2 between the step 53 of the spring seat 37 and the stopper 40 are oblique to the biasing direction of the spring 41. It is configured to be tied in a direction.

[0035] For example, the fuel intake valve shown in FIG. 3 (b) is provided between the edge 51a on the biasing direction side (upper side in the figure) of the spring 41 and the stopper 40 in the groove 51 of the nozzle piston 35, and A gap S is provided between the edge 53a of the step 53 of the spring sheet 37 opposite to the biasing direction of the spring 41 (the lower side in the figure) and the stopper 40. This is shown in Figure 6. In other words, the force acting on the stopper 40 from the spring seat 37 due to the urging force of the spring 41 and the force acting on the stopper 40 from the valve piston 35 due to the pushing down force of the nozzle piston 35 due to the fuel pressure in the fuel reservoir chamber diagonally The force acting on the stopper 40 can be changed from the shear direction to the compression direction. In general, since the allowable compressive stress is higher than the allowable shear stress for the same material, the durability of the fastener 40 can be improved.

[0036] Thus, in order to reduce the shearing force acting on the stopper, the spring between the edge of the spring biasing direction side of the valve piston groove and the stopper, or at the step of the spring seat A gap may be provided only between the edge on the opposite side of the biasing direction and the stopper.

 For example, FIG. 7A shows an example in which the gap S is provided only between the edge portion 51a of the spring portion 41 in the groove portion 51 of the valve piston 35 (upper side in the drawing) and the stopper 40. Even with this configuration, the force acting on the stopper 40 from the spring seat 37 and the force acting on the stopper 40 from the valve piston 35 can be exerted by acting in an oblique direction. It becomes like this. Therefore, the force acting on the stopper 40 is changed from the shearing direction to the compression direction, the shearing force acting on the stopper 40 can be reduced, and durability can be improved.

 FIG. 7B shows a gap only between the edge 53a of the step 53 of the spring seat 37 opposite to the biasing direction of the spring 41 (the lower side in the figure) and the stopper 40. This is an example in which S is provided. With this configuration, the force acting on the stopper 40 from the spring seat 37 and the force acting on the stopper 40 from the valve piston 35 can be applied in an oblique direction. Become. Therefore, the force acting on the stopper 40 is changed to the shear direction force compression direction, the shear force acting on the stopper 40 can be reduced, and durability can be improved.

[0038] In this manner, the edge and stopper between the edge of the groove of the nozzle piston on the biasing direction side of the spring and the stopper, and the edge of the spring seat on the opposite side of the spring biasing direction. For example, the groove or step has a cross-sectional shape that is larger than the diameter of the cross-section of the stopper, and the center of the circle that describes the arc is the valve piston. A predetermined gap can be provided by shifting the outer surface position force of the sensor. That is, when a gap is provided between the predetermined edge of the groove portion of the valve piston and the stopper, as shown in FIG. 8 (a), the center of the circle in the arc-shaped cross section of the groove portion 51 of the valve piston 35 is provided. By shifting the position Q from the outer surface position of the valve piston 35 toward the outer side in the outer circumferential direction, the curvature of the groove 51 becomes larger than the curvature of the stopper 40, and the predetermined gap S can be formed. Similarly, when a gap is provided between the spring seat cut-off portion and the stopper, as shown in Fig. 8 (b), a circle in the arc-shaped cross section of the cut-out portion 53 of the spring seat 37 is used. By shifting the center position Q from the outer surface position force of the valve piston 35 toward the inside of the valve piston 35, the curvature of the cut 53 becomes larger than the curvature of the stopper 40, and a predetermined gap S is formed. Can do.

 The “outer surface position of the valve piston” means a surface position on the outer side in the circumferential direction with respect to the axis of the valve piston and a surface position that exists when it is assumed that the surface position on the outer side in the circumferential direction extends.

 Further, as shown in FIG. 9, the predetermined gap S can also be formed by making the cross-sectional shapes of the groove 51 of the valve piston 35 and the step 53 of the spring seat 37 linear. it can. However, in the case of such a straight line shape, the stopper and the valve piston, or the spring seat and the stopper are in line contact, and the contact area becomes excessively small, and the pressure may be concentrated. . From this point of view, the contact area between the groove of the valve piston and the stopper and the contact area between the spring seat step and the stopper can be as large as possible, and rattling between the nozzle piston and the spring seat can be ensured. It is a more preferable aspect that the cross-sectional shape is an arc shape because it can be prevented.

 Further, as shown in FIG. 10, a frictional force generating member 55 is provided between the groove 51 of the valve piston 35 and the stopper 40 or between the step 53 of the spring seat 37 and the stopper 40. It is preferable to intervene.

By interposing the frictional force generating member 55, the contact position between the groove 51 of the valve piston 35 or the step 53 of the spring seat 37 and the stopper 40, that is, the point of action of the force applied to the stopper 40 Pl P2 can be maintained at a position where the edge forces of the groove 51 and the step 53 are also separated. Therefore, the force acting on the stopper 40 from the valve piston 35 and the spring seat 3 The force acting on the stopper 40 from 7 can be easily applied in an oblique direction, and the shearing force acting on the stopper 40 can be easily reduced.

[0041] In addition, the stopper that is locked to the groove portion of the valve piston and the step portion of the spring seat is particularly limited as long as it can be locked to both the groove portion and the step portion. In addition to the above-mentioned C-ring, clip members can be used.

 However, since it can be configured as a relatively small stopper so that it can be placed in the space of the holder portion of the fuel intake valve, it is preferable to use a C-ring. It is preferable to use a ring. By using such a C-ring as a stopper, while assuring the strength of the C-ring, when assembling the fuel intake valve, after expanding the C-ring and inserting the valve piston, the shape of the C-ring is changed to the original shape. It can be made to recover, and it can be made to latch in the groove part of a valve piston reliably.

 Powerful high-elastic alloys include Ni-Ti alloys and Co-Cr alloys, but are not limited to these.

[0042] Further, it is preferable that the valve piston and the spring seat constituting the fuel intake valve are made of carburized material and bearing steel. As described above, the fuel intake valve according to the fuel supply pump of the present invention employs a fixing method using a predetermined stopper as a method for fixing the spring seat to the valve piston. This is because the joining force by welding is not questioned as a material for the seat or valve piston.

 Therefore, the strength of the valve piston and spring seat can be increased, and even when a higher pressure fuel is pumped in large quantities, the durability of the fuel supply pump is improved and the fuel can be pumped stably. it can. Further, it is not necessary to provide a member such as a high-strength shim that prevents the wear of the spring sheet, so that the number of parts can be reduced and the assembling efficiency can be improved.

[0043] (9) Fuel discharge valve

Further, the fuel discharge valve 22 shown in FIG. 2 is disposed on the side of the fuel pressurizing chamber 14 in the cylindrical space l ib of the pump nosing 11 and is a part for transferring the pressurized fuel to a common rail or the like. It is. For example, in the fuel discharge valve 22, when the ball valve 61 is constantly urged in the valve closing direction by the spring 63, and the plunger 13 is pushed up by the cam 21, the fuel pressurizing chamber 14 becomes high pressure. The valve can be opened and the fuel can be allowed to pass therethrough.

[0044] 6. Example of use in piston pressure-accumulating fuel injection system

 The fuel supply pump according to the present invention described so far is a piston pressure-accumulation fuel injection type in which high pressure fuel supplied from a pressure accumulator (common rail) is further increased by a pressure-increasing piston and then an injector is also injected. It can be suitably used as a fuel supply pump used in the system (APCRS).

 Fig. 11 shows a configuration example of APCRS. This APCRS is composed of a fuel tank 62, a fuel supply pump 1 that pressurizes the fuel in the fuel tank 62 at a high pressure, and a pressure accumulator for accumulating the high-pressure fuel pumped from the fuel supply pump 1 ( The common rail) 66, the pressure increasing device (pressure increasing piston) 68 for further increasing the pressure of the fuel accumulated in the common rail 66, and the injector 70 are also configured.

[0045] The configuration of the common rail 66 is not particularly limited, and a publicly known one can be used. A plurality of injectors 70 are connected to the common rail 66, and the fuel whose pressure has been increased by the fuel supply pump 1 is evenly supplied to all the injectors 70. By controlling the injectors 70, an internal combustion engine (Fig. (Not shown) can be injected at a desired injection timing. By providing such a common rail 66, fuel can be injected into the engine via the injector 70 at an injection pressure commensurate with the rotational speed at which the rotation of the pump does not directly affect the injection pressure.

 In addition, a pressure detector (not shown) is connected to the common rail 66, and the pressure detection signal force obtained by the pressure detector is sent to an electronic control unit (ECU). Then, the ECU controls an electromagnetic control valve (not shown) similarly provided in the common rail 66 so that the common rail pressure becomes a predetermined pressure while receiving the pressure detection signal from the pressure detector.

Further, as illustrated in FIG. 11, as the pressure increasing device, a cylinder 75, a mechanical piston (pressure increasing piston) 74, a pressure receiving chamber 78, a pressurizing chamber 79, a solenoid valve 80, The mechanical piston 74 includes a pressure receiving portion 72, and a pressure portion 76 having a relatively smaller area than the pressure receiving portion 72. It can be set as the structure provided.

 In such a pressure increasing device, the mechanical piston 74 accommodated in the cylinder 75 moves while being pressed by the fuel having the common rail pressure in the pressure receiving portion 72, and the fuel in the pressurizing chamber 79 is compressed by the pressurizing portion 76. The pressure is increased.

That is, as shown in a schematic diagram in FIG. 12, the pressure increasing device is configured as a mechanical piston including a pressure receiving portion and a pressurizing portion having a relatively smaller area than the pressure receiving portion, and the stroke of the piston By considering the amount, it is possible to efficiently increase the pressure of the fuel having the common rail pressure while minimizing the pressure loss.

 More specifically, a machine having a common rail force fuel (pressure: pl, volume: VI, work: W1), a pressure receiving part having a relatively large area, and a pressure part having a relatively small area. A higher pressure fuel (pressure: p2, volume: V2, work: W2) can be achieved with the formula piston.

 In the pressure increasing device 68 shown in FIG. 11, a large amount of fuel having a common rail pressure is used to press the mechanical piston 74, but after pressurization, the fuel tank 6 is connected via the electromagnetic valve 80. Reflux to 2. That is, most of the fuel having the common rail pressure is returned to the fuel tank 62 via, for example, the line 93 after pressing the mechanical piston 74, and can be used again as high-pressure fuel.

 On the other hand, the fuel increased in pressure by the pressurizing unit 76 is sent to the injection hole 73 side of the injector 70 and injected, while the fuel discharged from the solenoid valve 71 is used for back pressure control of the injector 70. Is returned to the fuel tank 62 via the line 93.

 By providing such a pressure intensifying device, the mechanical piston can be effectively pressed by the fuel having the common rail pressure at any time without excessively increasing the size of the common rail.

[0049] The form of the injector 70 is not particularly limited. For example, as shown in FIG. 11, for example, a seating surface 102 on which the needle valve body 101 is seated, and the valve body of the seating surface 102 A nozzle body 103 having a nozzle hole 73 formed on the downstream side of the contact portion, and guides fuel to which the upstream force of the seating surface 102 is also supplied to the nozzle hole 73 when the double dollar valve body 101 is lifted It can be configured. In addition, the injector 70 always urges the dollar valve body 101 toward the seating surface 102 by a spring 104 or the like, and opens and closes the needle valve body 101 by switching energization of the solenoid (not shown) Z de-energization. It can be set as a solenoid valve type.

 In such a pressure-accumulation type accumulator fuel injection system, the power required for a fuel supply pump capable of pumping a large amount of higher pressure fuel to the common rail is required. For example, the durability of the fuel intake valve is improved, and it can withstand long-term use even when used in APCRS. Therefore, a large amount of high-pressure fuel can be stably supplied even when high-pressure and high-speed operation is performed for a long time.

Claims

The scope of the claims  [1] In a fuel supply pump comprising a fuel pressurizing chamber for increasing the pressure of fuel and a fuel intake valve for supplying fuel to the fuel pressurizing chamber,  The fuel intake valve includes a valve body, a valve piston having a flange portion on one end side and slidably held by the valve body, a spring for biasing the valve piston in a valve closing direction, and the valve piston A spring seat that is fixed near the end opposite to the one end side and receives one end of the spring,  The valve piston has a groove portion, on the outer surface near the opposite end portion, in which a stopper for fixing the valve piston and a spring seat is locked.  The spring seat has an opening into which the valve piston is inserted, and has a step portion with which the stopper is locked along an edge of the opening.  After the valve piston is inserted into the opening of the spring seat, the stopper is engaged with the groove of the valve piston, and the spring seat is urged by the spring to place the stopper on the stepped portion. By locking, the spring seat is fixed to the nozzle piston,  A gap is provided between at least one of an edge of the groove portion on the biasing direction side or an edge of the step portion opposite to the biasing direction and the stopper. Fuel supply pump.  [2] The cross-sectional shape of the groove portion or the step portion is an arc shape, and the gap is provided by shifting the position of the outer surface position force of the valve piston with respect to the center of a circle describing the arc. The fuel supply pump according to paragraph 1 of the scope. [3] The fuel supply pump according to claim 1 or 2, wherein a frictional force generation member is interposed between the groove or step and the stopper. [4] The fuel supply pump according to any one of [1] to [3], wherein the stopper is a C-ring having an alloy force having high elasticity. [5] The fuel supply pump according to any one of claims 1 to 4, wherein the nozzle piston and the spring seat are made of a carburized material or a bearing steel. [6] A fuel pressurizing chamber for increasing the pressure of fuel, and a fuel for supplying fuel to the fuel pressurizing chamber A fuel supply pump comprising a fuel intake valve;  The fuel intake valve includes a valve body, a valve piston having a flange portion on one end side and slidably held by the valve body, a spring for biasing the valve piston in a valve closing direction, and the valve piston A spring seat that is fixed near the end opposite to the one end side and receives one end of the spring,  The valve piston has a groove portion, on the outer surface near the opposite end portion, in which a stopper for fixing the valve piston and a spring seat is locked.  The spring seat has an opening into which the valve piston is inserted, and has a step portion with which the stopper is locked along an edge of the opening.  After the valve piston is inserted into the opening of the spring seat, the stopper is engaged with the groove of the valve piston, and the spring seat is urged by the spring to place the stopper on the stepped portion. By locking, the spring seat is fixed to the nozzle piston,  The fuel supply pump, wherein the contact portion between the groove portion and the stopper and the contact portion between the stepped portion and the stopper are connected obliquely with respect to the biasing direction.