KR20110101145A - Fuel injection pump - Google Patents

Abstract

Provided is a fuel injection pump 1 which solves the problem that lubricating oil is mixed in the fuel through the gap between the plunger 10 and the plunger barrel 11 and blackening of the fuel occurs. The plunger (12a) provided in the partition wall between the tappet chamber 16 below the plunger barrel 11 and the cam chamber 23 provided below the tappet chamber 16, and the plunger (12a), 10) A fuel injection pump having a roller tappet 20 connected to the lower end, the roller tappet 20 being reciprocally sliding along the protruding guide portion 12a of the pump case 12 in association with the rotational movement of the cam 21. As (1), the upper end of the roller tappet 20 always protrudes toward the plunger barrel 11 side from the upper end surface of the protruding guide portion 12a throughout the sliding stroke.

Description

Fuel Injection Pump {FUEL INJECTION PUMP}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection pump of a fuel injection device mounted on an engine, and more particularly, to a structure related to prevention of mixing of lubricating oil into fuel in a fuel injection pump.

Background Art Conventionally, in a fuel injection pump of a fuel injection device mounted on an engine, a structure related to prevention of mixing of lubricating oil into fuel is known (see Patent Document 1, for example).

The fuel injection pump described in patent document 1 is provided with the communication path which communicates a tappet inside and a tappet outside.

The fuel injection pump described in Patent Literature 1 can prevent lubricating oil from accumulating in the tappet and being mixed in fuel by lubricating oil introduced into the tappet by being discharged to the tappet outside by the communication passage.

Patent Document 1: Japanese Patent Application Laid-Open No. 2005-146984

However, the fuel injection pump described in Patent Document 1 cannot prevent the lubricating oil from splashing into the plunger.

That is, in the fuel injection pump described in Patent Document 1, the lubricating oil splashed on the plunger is mixed in the fuel through the gap between the plunger and the plunger barrel, whereby the fuel is blackened and the fuel is injected by incomplete combustion. There has been a problem that deterioration of exhaust smoke due to adhesion of a carbon flower to the nozzle splitter occurs.

The problem to be solved of the present invention is as described above, and then the means for solving the problem will be described.

That is, in this invention, a pump case, the hydraulic head provided in the upper part of this pump case, the plunger barrel inserted in this hydraulic head, the plunger which slides inside the said plunger barrel, and the said plunger barrel below, A protruding guide portion provided in a partition wall between the tappet chamber and a cam chamber provided below the tappet chamber, a tappet inserted into the protruding guide portion and connected to the lower end of the plunger, and provided inside the cam chamber below the tappet. And a cam contacting the tappet, wherein a pressurized chamber is provided between the upper end of the plunger and the plunger barrel to pressurize the fuel, and the tappet interlocks with the rotational movement of the cam. A fuel injection pump capable of reciprocating sliding along a section, the upper end of the tappet having the protruding guide in the entirety of the sliding stroke. From the top surface portion it will always be projected toward the plunger barrel.

In this invention, it is provided with the scattering prevention member which protrudes in the direction orthogonal to the sliding direction of the said tappet, and prevents lubricating oil from splashing on the said plunger.

In the present invention, the scattering preventing member is formed in a structure separate from the tappet.

In the present invention, the pump case is provided with a cam chamber incorporating the cam member, a rack chamber incorporating a rack (rack) is provided on the upper surface of the pump case, the cam chamber and the rack chamber is vented ( and an inflow preventing member for preventing lubricating oil from flowing into the vent hole.

In the present invention, the fuel injection pump includes a delivery valve for preventing fuel from flowing into the pressurizing chamber, a distribution shaft for distributing the pumped fuel to the delivery valve, and a coaxial axis with the distribution shaft. And a transmission shaft for transmitting power to the distribution shaft and a positioning member for determining an axial position of the transmission shaft, wherein the inflow preventing member is fastened together with the positioning member and attached to the pump case. .

In the present invention, a pump case, a hydraulic head provided on an upper portion of the pump case, a plunger barrel inserted in the hydraulic head, a plunger sliding inside the plunger barrel, a tappet chamber below the plunger barrel and the tappet And a projection provided in the partition wall between the cam chambers provided below the chamber, a tappet inserted into the projection guide and connected to the lower end of the plunger, and a cam provided in the cam chamber below the tappet and in contact with the tappet. And a pressurized chamber in which fuel is pressurized between an upper end of the plunger and the plunger barrel, and the tappet is a fuel injection pump that can reciprocally slide along the protruding guide of the pump case in association with a rotational movement of the cam. And a covering member covering the gap between the plunger barrel and the entire sliding stroke of the tappet. It is.

In this invention, it has a ventilation hole which exhausts gas in the said tappet.

In this invention, it has a receiving part which receives the edge part by the side of the said plunger barrel of the said biasing member.

In the present invention, the tappet has a cam top portion that maintains a state positioned at a top dead center.

As an effect of this invention, the effect as shown below is exhibited.

In the present invention, the splashing of the lubricating oil on the plunger can be prevented by the protruding portion of the tappet, and the incorporation of the lubricating oil into the fuel can be prevented. Deterioration of the exhaust smoke resulting from carbon flower adhesion can be suppressed.

In the present invention, the splashing of the lubricating oil on the plunger can be prevented by the scattering preventing member, and the mixing of the lubricating oil in the fuel can be prevented, so that the carbon into the fuel injection nozzle splitting part due to blackening of the fuel and incomplete combustion The deterioration of the exhaust smoke resulting from flower adhesion can be suppressed.

In this invention, since the external shape of a tappet does not become complicated, the grinding process of a tappet outer periphery is easy and manufacturing cost can be held down.

In the present invention, since the inflow preventing member can prevent the lubricating oil from flowing into the vent hole, the lubricating oil having passed through the vent hole does not splash on the plunger. As a result, the mixing of lubricating oil into the fuel can be prevented, so that the deterioration of the exhaust smoke due to the blackening of the fuel and adhesion of carbon flowers to the fuel injection nozzle outlet portion due to incomplete combustion can be suppressed.

In the present invention, since the inflow preventing member and the positioning member can be attached at one time, the efficiency of the attaching operation is improved.

In the present invention, since the gap between the tappet and the plunger barrel is covered by the covering member, it is possible to prevent the lubricant from splashing on the plunger through the gap between the tappet and the plunger barrel. As a result, the mixing of lubricating oil into the fuel can be prevented, so that the deterioration of the exhaust smoke due to the blackening of the fuel and adhesion of carbon flowers to the fuel injection nozzle outlet portion due to incomplete combustion can be suppressed.

In the present invention, even when the gap between the tappet and the plunger barrel is covered by the covering member, gas discharge inside the tappet can be ensured.

In the present invention, since there is no need to provide a dedicated member that receives the biasing member, the number of parts can be reduced, and the part cost can be reduced.

In the present invention, since the tappet is held at the top dead center, the lubricant from the space accommodating the cam (hereinafter referred to as the 'cam chamber') becomes less likely to splash on the plunger, thereby preventing the incorporation of lubricant into the fuel. The deterioration of the exhaust smoke due to carbon flower adhesion to the fuel injection nozzle splitter due to blackening of the fuel and incomplete combustion can be suppressed.

1 is a side cross-sectional view showing a state where a roller tappet is located at a top dead center as a fuel injection pump according to a first embodiment of the present invention.
2 is a front sectional view of FIG. 1.
3 is a side sectional view showing a state where a roller tappet is located at a bottom dead center as a fuel injection pump according to a first embodiment of the present invention.
4 is a front sectional view of FIG. 3.
5 is a side view of the cam.
6 is a plan view illustrating the inflow preventing member.
7 is a cross-sectional view taken along line AA ′ of FIG. 6 showing the inflow preventing member.
8 is a sectional view showing an inflow preventing member according to a modification.
9 is a partial front sectional view of the roller tappet.
10 is a front sectional view showing a fuel injection pump having a roller tappet according to a modification.
11 is a partial front sectional view showing a roller tappet provided in the fuel injection pump according to the second embodiment of the present invention.

Next, the form for implementing invention is demonstrated.

First, the fuel injection pump 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 10.

On the other hand, hereinafter, for convenience, the direction in which gravity acts on the basis of the posture when the fuel injection pump 1 is attached to the engine is defined as 'down' and the direction opposite to the direction in which gravity acts is 'upward'. Define the 'up and down' direction, define the 'front and rear direction' as the direction perpendicular to the up and down direction, define the 'left and right direction' as the direction perpendicular to the up and down direction and the front and back direction, and these defined directions Explain using

In addition, arrow T direction shown in FIG. 1 is an upward direction, arrow D direction is downward direction, arrow F direction is a forward direction, and arrow Re direction is a backward direction. In addition, the arrow Ri direction shown in FIG. 2 is a right direction, and the arrow L direction is a left direction, and it is the same also in the following figure.

As shown in FIG. 1 to FIG. 4, the fuel injection pump 1 which concerns on 1st Example is a component which comprises the fuel injection apparatus of an engine, and conveys fuel at high pressure. The fuel injection pump 1 is a distribution type fuel injection pump which distributes and delivers fuel by one plunger 10 to each cylinder (not shown) of an engine.

The plunger 10 is provided in the plunger barrel 11 so as to reciprocate in the vertical direction. The plunger barrel 11 is inserted into the hydraulic head 13 provided on the upper part of the pump case 12. In the hydraulic head 13, a thermoelement 14, which is a cold start timer mechanism, is provided on the right side with the plunger barrel 11 interposed therebetween, and an accumulator on the left side with the plunger barrel 11 interposed therebetween. (37) is provided. Between the plunger barrel 11 and the upper end of the plunger 10, a pressurizing chamber 15 communicating with a fuel tank (not shown) is formed.

The lower end of the plunger barrel 11 is inserted into the tappet chamber 16 formed in the vertical direction on the upper part of the pump case 12. The plunger 10 protrudes downward from the lower end of the plunger barrel 11 in the tappet chamber 16. The upper spring support 17 is fixed to the outer circumference of the lower end of the plunger barrel 11, and the lower spring support 18 is fixed to the lower end of the plunger 10. A spring 19 is provided between the upper surface of the lower spring bearing 18 and the lower surface of the upper spring bearing 17 to impart a downward biasing force to the plunger 10. The roller tappet 20 is provided at the lower end of the plunger 10 so as to reciprocate in the vertical direction along the protruding guide 12a of the pump case 12.

Meanwhile, FIGS. 1 and 2 illustrate a fuel injection pump 1 having a roller tappet 20 at a top dead center, and FIGS. 3 and 4 illustrate fuel injection with a roller tappet 20 at a bottom dead center. The pump 1 is shown.

The roller tappet 20 is a cylindrical shape opened upwards. The lower spring support 18 is fixed inside the roller tappet 20, and the roller tappet 20 is biased downward together with the plunger 10 by the spring 19 through the lower spring support 18. In the lower part of the roller tappet 20, the roller part 201 which contacts the cam 21 is axially rotatable through the roller shaft 202. An adjusting shim 206 is provided between the upper surface of the roller tappet 20 and the lower surface of the lower spring bearing 18. The adjustment shim 206 adjusts the gap between the cam 21 and the roller tappet 20 to an appropriate value.

The cam 21 is fixed on the camshaft 22 and is accommodated in the front part inside the cam chamber 23 formed in the lower part of the pump case 12. The inside of the cam chamber 23 is filled with lubricating oil, and the cam 21 is lubricated by this lubricating oil. The camshaft 22 is constructed in the front-back direction inside the cam chamber 23, and is axially rotatable to the pump case 12 via the bearing 221. As shown in FIG.

From the front of the pump case 12, the front end of the camshaft 22 protrudes forward, and the power from the crankshaft (not shown) of the engine is applied to the front protruding portion of the camshaft 22. The gear 222 to be transmitted is fixed. The rear end of the camshaft 22 protrudes rearward from the rear part of the pump case 12, and the governor sleeve which is a component which comprises a governor mechanism (not shown) in the rear protrusion of the camshaft 22. As shown in FIG. 24 and the governor weight 25 are provided.

Bevel gears 223 fixed on the camshaft 22 are accommodated in the rear portion of the cam chamber 23. From the rear upper surface inside the cam chamber 23, the pump case 12 is pivotally rotatable, and the lower end of the transmission shaft 26 hypothesized in the vertical direction protrudes downward. Bevel gears 261 engaged with the bevel gears 223 are fixed to the lower end of the transmission shaft 26.

While the upper end of the transmission shaft 26 is pivotally rotatable to the bearing portion 121 of the pump case 12, the position in the axial direction (up and down direction) is determined by the positioning member 28. . On the upper side of the pump case 12 above the transmission shaft 26, a rack chamber 27 containing a rack (not shown) which is a component constituting the injection amount adjusting mechanism of the fuel injection pump 1 is formed. The rack chamber 27 communicates with the cam chamber 23 by the vent hole 30.

The vent 30 communicates from the rack chamber 27 to the cam chamber 23 in the pump case 12. The opening end surface (opening end surface of the rack chamber 27 side) of the upper end of the ventilation hole 30 is covered by the inflow prevention member 31 (refer FIG. 6 and FIG. 7).

A dispensing shaft 32 is fixed to the upper end of the transmission shaft 26 via the joint 33 on the same axis as the transmission shaft 26. The inside of the distribution shaft 32 and the pressurizing chamber 15 are communicated by the flow path 131 formed in the hydraulic head 13 inside. On the rear side of the distribution shaft 32 of the hydraulic head 13, it becomes a backflow prevention valve at the end of the injection of the fuel injection pump 1, and it turns out that the fuel in an injection pipe (not shown) flows out into the pressurizing chamber 15 inside. The delivery valve 34 which prevents is provided through the holder 341.

In the fuel injection pump 1 according to such a configuration, when the cam 21 is rotated, the roller tappet 20 is reciprocated in the vertical direction by the rotation of the cam 21, and the roller tappet 20 is connected to the roller tappet 20. The plunger 10 is also reciprocated through the fixed lower spring support 18. At this time, the lubricating oil filling the cam chamber 23 by the reciprocating motion of the roller tappet 20 and the lubricating oil lubricated on the outer circumferential surface of the roller tappet 20 are the outer circumferential surface of the roller tappet 20 and the tappet chamber 16. ) Through the gap of the inner circumferential wall.

And the suction stroke of the fuel to the pressurizing chamber 15 and the discharge stroke of the fuel from the pressurizing chamber 15 are performed by the reciprocating motion of the plunger 10 alternately. That is, when the plunger 10 is pushed down by the biasing force of the spring 19 in the suction stroke and lowered, the fuel from the fuel tank is sucked into the pressurizing chamber 15, and the plunger 10 is the spring ( When it is pushed up and raised by the biasing force of 19, the fuel sucked in the pressurizing chamber 15 is pressurized and is conveyed to the distribution shaft 32 through the flow path 131. As shown in FIG.

Thereafter, the fuel pumped to the distribution shaft 32 is distributed to the delivery valve 34 by the distribution shaft 32 and injected from the fuel injection nozzle (not shown) through the injection pipe.

Next, the cam 21 will be described with reference to FIG. 5.

As shown in FIG. 5, the cam 21 has a constant spacing around the center 213 of the base circle portion 211 at the edge of the base circle portion 211 (spaced 120 degrees with respect to the center 213). Three cam nose parts 212 are provided.

On the other hand, since the structure of the cam nose part 212 is substantially the same, it demonstrates centering around one cam nose part 212 in the following description, and the other cam nose part 212 is demonstrated only when necessary.

The cam nose portion 212 has a cam top portion 212A. The cam top portion 212A is an arc shape formed at a constant radius r from the center 213 of the base circle portion 211. That is, the cam top portion 212A has a shape that can be maintained in a state where the roller tappet 20 is located at the top dead center.

Next, the inflow prevention member 31 is demonstrated, referring FIG. 6 and FIG.

As shown in FIG. 6 and FIG. 7, the inflow preventing member 31 has a substrate 311 and a pair of side plates 312. The inflow preventing member 31 is fixed by the bolt 29 to the accumulator 121 of the pump case 12 together with the positioning member 28. That is, the inflow prevention member 31 is fastened with the positioning member 28 by the bolt 29, and is attached to the storage part 121 of the pump case 12. As shown in FIG. The long side at the side of the transmission shaft 26 of the board | substrate 311 is cut | disconnected in the shape (approximately arc-shaped) according to the outer peripheral shape of the transmission shaft 26. As shown in FIG.

The board | substrate 311 and the pair of side plates 312 are each a substantially rectangular plate-shaped member. Long sides of the pair of side plates 312 are respectively connected to the pair of short sides of the substrate 311.

In this embodiment, after the pair of side plates 312 protrude in parallel with the plate surface of the substrate 311 from a portion of the pair of short sides of the substrate 311, a sheet of metal plate is molded. The metal plate is bent so that the plate surface of the substrate 311 and the plate surface of the pair of side plates 312 are substantially perpendicular at the boundary between the pair of short sides of the substrate 311 and the pair of side plates 312, thereby preventing inflow. The member 31 is comprised. That is, the inflow prevention member 31 has a pair of side plates (outside of the side where the one ventilation hole 30 and the other ventilation hole 30 oppose) of the ventilation hole 30 when viewed from the left-right direction ( 312) is a roughly shaped door.

Between the inflow prevention member 31 and the pump case 12, predetermined clearance gap D1, D2, D3, D4 is formed so that the gas discharge by the ventilation hole 30 may be performed smoothly.

Specifically, between the plate surface of the board | substrate 311 on the side facing the horizontal surface 123 of the pump case 12, and the opening end surface of the upper end part of the ventilation hole 30 (opening end surface of the rack chamber 27 side). Gap D1 (see FIG. 7), the gap D2 between the vertical surface 122 of the pump case 12 and the long side of the substrate 311 facing the vertical surface 122 and the short sides of the pair of side plates 312, the bearing part. The clearance gap D3 and the horizontal surface 123 of the pump case 12 and the pair of side plates opposing the horizontal surface 123 between the 121 and the short sides of the pair of side plates 312 facing the bearing portion 121. A gap D4 is formed between the long sides of 312.

On the other hand, the inflow preventing member 31 according to the present embodiment is formed by bending (pressing) the plate member, but the inflow preventing member according to the present invention is, for example, by welding or screwing a plurality of members. In combination, or as shown in FIG. 8, you may comprise with the baffle plate 35. As shown in FIG.

As shown in FIG. 8, the baffle plate 35 has a shape in which a predetermined gap D5 is formed between an opening end face (an opening end face on the rack chamber 27 side) of the upper end of the vent hole 30 (for example, , A shape bent in a direction spaced apart from the opening end face of the vent hole 30). The baffle plate 35 is fixed in the rack chamber 27 by welding or screwing on the horizontal surface 123 of the pump case 12 or the like.

Next, the structure concerning prevention of mixing of the lubricating oil in the fuel of the roller tappet 20 is demonstrated, referring FIG.

As shown in FIG. 9, the upper part of the roller tappet 20 always protrudes upwards (the plunger barrel 11 side) from the upper end of the protruding guide part 12a of the pump case 12 in the whole range of the sliding stroke 203. As shown in FIG. do. That is, the upper end part of the roller tappet 20 is always located above (the plunger barrel 11 side) upper end part T of the protrusion guide part 12a of the pump case 12 shown in FIG. The scattering prevention member 204 is provided in the upper part of the roller tappet 20.

The scattering prevention member 204 protrudes in the horizontal direction (the direction orthogonal to the sliding direction of the roller tappet 20) over the entire circumference of the outer surface of the roller tappet 20 so that the lubricant splashes on the plunger 10. prevent. The shape of the scattering prevention member 204 is, for example, an "approximately ring shape" when viewed from the sliding direction (up-down direction) of the roller tappet 20.

On the other hand, the shape of the scattering prevention member according to the present invention may be a shape that covers the gap between the outer peripheral surface of the tappet and the inner peripheral wall of the tappet chamber. Preferably, for example, the shape of the shatterproof member 204 is larger than the opening area of the tappet chamber 16 in the area surrounding the outer circumference of the shatterproof member 204, and the shatterproof member 204 may be formed. The outer circumferential surface of the roller tappet 20 and the tappet chamber are located between the outer circumferential surface of the roller tappet 20 and the inner circumferential wall of the tappet chamber 16 within the range surrounding the outer circumference (by the scattering preventing member 204 when viewed from above). The gap between the inner circumferential walls of (16) is not seen), whereby lubricating oil can be reliably prevented from splashing into the plunger 10.

With this configuration, with the reciprocating motion of the roller tappet 20, lubricant oil from the cam chamber 23 side is upwardly through a gap between the outer circumferential surface of the roller tappet 20 and the inner circumferential wall of the tappet chamber 16. Even if it is shifted (hereinafter referred to as 'transition lubricant'), the transition lubricant does not exceed the upper end of the roller tappet 20, and splashes of the transition lubricant are blocked by the scattering preventing member 204 ( Arrow 205 shown in FIG. 9).

As described above, the fuel injection pump 1 according to the first embodiment of the present invention includes a pump case 12, a hydraulic head 13 provided above the pump case 12, and a hydraulic head 13. The plunger barrel 11 inserted into the plunger barrel 11, the plunger 10 sliding inside the plunger barrel 11, and the cam chamber 23 provided below the tappet chamber 16 and the tappet chamber 16 under the plunger barrel 11. ) Projecting guide portion 12a provided on the partition wall, roller tappet 20 inserted into projecting guide portion 12a and connected to the lower end of plunger 10, and cam chamber 23 under roller tappet 20. With a cam 21 provided therein and contacting the roller tappet 20, a pressurizing chamber 15 is provided between the upper end of the plunger 10 and the plunger barrel 11 to pressurize the fuel, and the roller tappet 20 ) Is a fuel injection pump (1) capable of reciprocating sliding along the protruding guide portion (12a) of the pump case (12) in conjunction with the rotational movement of the cam (21), the roller tappet The upper end of 20 is always protruding toward the plunger barrel 11 side from the upper end surface of the protruding guide portion 12a throughout the sliding stroke.

Such a structure prevents the lubricating oil from splashing on the plunger 10 by the protruding portion of the roller tappet 20, thereby preventing the mixing of the lubricating oil into the fuel, thereby making the fuel black and incomplete combustion. Deterioration of the exhaust smoke caused by adhesion of carbon flowers to the fuel injection nozzle splitter can be suppressed.

And it is provided with the scattering prevention member 204 which protrudes in the direction orthogonal to the sliding direction of the roller tappet 20, and prevents lubricating oil from splashing on the plunger 10. As shown in FIG.

With such a configuration, the splashing of the lubricating oil to the plunger 10 can be prevented by the scattering preventing member 204, so that the mixing of the lubricating oil into the fuel can be prevented, resulting in blackening of the fuel and incomplete combustion. Deterioration of the exhaust smoke resulting from carbon flower adhesion to the fuel injection nozzle splitter can be suppressed.

In addition, the shatterproof member 204 is formed in a structure separate from the roller tappet 20.

By such a structure, since the outer shape of the roller tappet 20 does not become complicated, the grinding process of the outer periphery of the roller tappet 20 is easy, and manufacturing cost can be held down.

In addition, in the fuel injection pump 1, the cam chamber 23 and the rack chamber 27 communicate with each other by the air vent 30, and an inflow preventing member for preventing lubricating oil from flowing into the air vent 30 ( 31).

With such a configuration, since the inflow preventing member 31 can prevent the lubricating oil from flowing into the vent hole 30, the lubricating oil having passed through the vent hole 30 does not splash on the plunger 10. As a result, the mixing of lubricating oil into the fuel can be prevented, so that the deterioration of the exhaust smoke due to the blackening of the fuel and adhesion of carbon flowers to the fuel injection nozzle outlet portion due to incomplete combustion can be suppressed.

Then, the transmission shaft 26 is provided coaxially with the distribution shaft 32 of the fuel injection pump 1 to transfer power to the distribution shaft 32, and to determine the position in the axial direction of the transmission shaft 26. The positioning member 28 is provided, and the inflow prevention member 31 is fastened and attached together with the positioning member 28.

With such a configuration, since the inflow preventing member 31 and the positioning member 28 can be attached at one time, the efficiency of the attaching operation is improved.

In addition, the cam 21 has a cam top portion 212A for maintaining the state where the roller tappet 20 is located at the top dead center.

With this configuration, since the roller tappet 20 is held at the top dead center, it is difficult for the lubricant oil from the cam chamber 23 side to splash on the plunger 10, thereby preventing the mixing of lubricant oil into the fuel. Deterioration of the exhaust smoke due to carbon flower adhesion to the fuel injection nozzle splitter due to blackening and incomplete combustion can be suppressed.

In addition, although the fuel injection pump 1 which concerns on this embodiment provided the scattering prevention member 204 in the upper part of the roller tappet 20, as shown in FIG. 10, scattering prevention is carried out in the upper part of the roller tappet 20. FIG. It is also possible to configure the fuel injection pump 1 without providing the member.

Next, the fuel injection pump 1 which concerns on 2nd Example of this invention is demonstrated, referring FIG. 11, members having the same reference numerals as those in the first embodiment are the same as those in the first embodiment, and thus detailed descriptions thereof will be omitted.

As shown in FIG. 11, the fuel injection pump 1 which concerns on 2nd Example is provided with the cover member 36. As shown in FIG.

The covering member 36 covers the gap between the roller tappet 20 and the plunger barrel 11 over the entire sliding stroke of the roller tappet 20. The covering member 36 is a cylindrical shape opened downward. The inner diameter of the covering member 36 is slightly larger than the outer diameter of the roller tappet 20. That is, the roller tappet 20 can slide inside the covering member 36. The covering member 36 has a receiving part 361 and a covering part 362.

The receiving part 361 is a part which receives the upper end part (end part of the plunger barrel 11 side) of the spring 19. As shown in FIG. The coating 362 is a portion covering the gap between the roller tappet 20 and the plunger barrel 11 over the entire sliding stroke of the roller tappet 20. The covering part 362 is provided with a ventilation hole 362A through which gas is discharged inside the roller tappet 20.

The vent 362A is located above the upper end of the roller tappet 20 throughout the sliding stroke of the roller tappet 20. That is, the ventilation hole 362A is provided at a position which is not blocked by the roller tappet 20.

In addition, the shape, number, and provision position of the ventilation hole which concern on this invention are not limited. That is, the ventilation hole which concerns on this invention should just be a shape, number, and provision position which can discharge gas inside a tappet.

With such a configuration, the transition lubricant is blocked by the covering member 36 (coating part 362) and cannot flow into the roller tappet 20, and the droplets of the transition lubricant are also coated with the coating member 36 (coating part ( 362)).

As described above, in the fuel injection pump 1 according to the second embodiment of the present invention, the plunger 10 is provided to reciprocally slide in the plunger barrel 11, and one end of the plunger 10 and the plunger barrel are provided. A pressurization chamber 15 through which fuel is pressurized is provided between the 11, while the other end of the plunger 10 protrudes from the plunger barrel 11 in a direction opposite to the pressurization chamber 15 to interlock with the roller tappet 20. The roller tappet 20 is a fuel injection pump 1 capable of reciprocally sliding inside the tappet chamber 16 containing the plunger barrel 11 and the plunger 10 by direct drive by the cam 21, The covering member 36 which covers the clearance of the roller tappet 20 and the plunger barrel 11 over the sliding stroke of the roller tappet 20 is provided.

With this configuration, since the gap between the roller tappet 20 and the plunger barrel 11 is covered by the covering member 36, the lubricating oil is plunged through the gap between the roller tappet 20 and the plunger barrel 11. 10) can prevent splashing. As a result, the mixing of lubricating oil into the fuel can be prevented, so that the deterioration of the exhaust smoke due to the blackening of the fuel and adhesion of carbon flowers to the fuel injection nozzle outlet portion due to incomplete combustion can be suppressed.

And the covering member 36 has the ventilation hole 362A which performs gas discharge | emission inside the roller tappet 20. As shown in FIG.

By such a structure, even when the clearance gap between the roller tappet 20 and the plunger barrel 11 is covered by the coating member 36, the gas discharge inside the roller tappet 20 can be ensured.

Moreover, it is provided with the spring 19 as a bias member which biases the plunger 10 to the cam 21 direction, and the covering member 36 receives the receiving part which receives the edge part by the side of the plunger barrel 11 of the spring 19 ( 361).

By such a structure, since it is not necessary to provide the exclusive member which receives the spring 19, a component number can be reduced and a component cost can be reduced.

One… Fuel injection pump
11 ... Plunger barrel
10... plunger
15... Pressurized chamber
16... Tappet chamber
19 ... Spring (biased member)
20... Roller Tappet
21 ... Cam (without cam)
23 ... Cam chamber
26... Transmission shaft
27 ... Rack chamber
28 ... Positioning member
30... Aeration
31... Inflow prevention member
32... Distribution shaft
36... Cladding
204... Shatterproof member
212A... Cam top
361... Receiving part
362A... Aeration

Claims (9)

With pump case,
A hydraulic head provided on an upper portion of the pump case;
A plunger barrel inserted into the hydraulic head,
A plunger sliding inside the plunger barrel;
A protruding guide portion provided on a partition wall between the tappet chamber below the plunger barrel and the cam chamber provided below the tappet chamber;
A tappet inserted into the protruding guide part and connected to a lower end of the plunger;
Has a cam provided inside the cam chamber below the tappet and in contact with the tappet,
Between the upper end of the plunger and the plunger barrel is provided a pressure chamber for pressurizing the fuel,
The tappet is a fuel injection pump capable of reciprocating sliding along the protruding guide of the pump case in conjunction with the rotational movement of the cam,
And the upper end portion of the tappet always protrudes from the upper end surface of the protruding guide portion to the plunger barrel side throughout the sliding stroke. The method of claim 1,
And a scattering preventing member protruding in a direction perpendicular to a sliding direction of the tappet to prevent lubricating oil from splashing on the plunger. The method of claim 2,
The scattering prevention member is a fuel injection pump, characterized in that formed in a separate structure from the tappet. The method of claim 3,
The pump case is provided with a cam chamber incorporating the cam member, a rack chamber incorporating a rack is provided on an upper surface of the pump case, and the cam chamber and the rack chamber communicate with each other by a ventilation hole, and the ventilation hole is provided. A fuel injection pump, comprising: an inflow preventing member for preventing lubricating oil from flowing inside. The method of claim 4, wherein
The fuel injection pump includes a delivery valve for preventing fuel from flowing into the pressurizing chamber, a distribution shaft for distributing the pumped fuel to the delivery valve, and coaxially with the distribution shaft to transfer power to the distribution shaft. And a transmission shaft and a positioning member for determining a position in the axial direction of the transmission shaft, wherein the inflow preventing member is engaged with the positioning member and attached to the pump case. With pump case,
A hydraulic head provided on an upper portion of the pump case;
A plunger barrel inserted into the hydraulic head,
A plunger sliding inside the plunger barrel;
A protruding guide portion provided on a partition wall between the tappet chamber below the plunger barrel and the cam chamber provided below the tappet chamber;
A tappet inserted into the protruding guide part and connected to a lower end of the plunger;
Has a cam provided inside the cam chamber below the tappet and in contact with the tappet,
Between the upper end of the plunger and the plunger barrel is provided a pressure chamber for pressurizing the fuel,
The tappet is a fuel injection pump capable of reciprocating sliding along the protruding guide of the pump case in conjunction with the rotational movement of the cam,
And a covering member covering the gap between the tappet and the plunger barrel over the sliding stroke of the tappet. The method of claim 6,
And the covering member has a vent hole for discharging gas inside the tappet. The method of claim 7, wherein
And the covering member has a receiving portion receiving an end portion on the plunger barrel side of the biasing member. The method according to any one of claims 1 to 8,
And the cam member has a cam top portion for maintaining the state where the tappet is located at the top dead center.

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