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JPH0412166A - Check valve of fuel injection pump - Google Patents

Check valve of fuel injection pump

Info

Publication number
JPH0412166A
JPH0412166A JP11394390A JP11394390A JPH0412166A JP H0412166 A JPH0412166 A JP H0412166A JP 11394390 A JP11394390 A JP 11394390A JP 11394390 A JP11394390 A JP 11394390A JP H0412166 A JPH0412166 A JP H0412166A
Authority
JP
Japan
Prior art keywords
hole
return
discharge
fuel injection
discharge pipe
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP11394390A
Other languages
Japanese (ja)
Inventor
Shohei Ito
伊藤 昇平
Toru Okazaki
透 岡崎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Denso Corp
Original Assignee
NipponDenso Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NipponDenso Co Ltd filed Critical NipponDenso Co Ltd
Priority to JP11394390A priority Critical patent/JPH0412166A/en
Publication of JPH0412166A publication Critical patent/JPH0412166A/en
Pending legal-status Critical Current

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  • Fuel-Injection Apparatus (AREA)

Abstract

PURPOSE:To restrain undesirable increase of injection quantity at high rotating speed territory by constituting the check valve of a fuel injection pump so that an intercepting body of a return hole having a restriction part to decrease fluid resistance of the return hole accompanied wit increase of lift of a valve separately provided against the intercepting part. CONSTITUTION:The check valve (delivery valve) of a fuel injection pump is constituted by inserting a discharge hole intercepting body 2 of cylindrical shape into a discharge hole 10 penetratably formed in a base cylinder part 1, and the lower face 22a of the flange part 22 of the top part of the intercepting body 2 and the upper end edge of the discharge hole 10 are respectively formed into slopes 22b, 12b of truncated cone face mutually close- contacted. The body 2 is energizated so as to close valve with a first spring 6 for setting discharge pressure. A return hole 25 is penetratably provided along the axis in the center of the intercepting body 2, and a return hole intercepting body 3 having a circular section is inserted in the hole 25. The intercepting body 3 is formed out of a base part 3a of large diameter and a restriction part 3b of small diameter, and upward energizated with a second spring 4 for setting back flow pressure.

Description

【発明の詳細な説明】 [産業上の利用分野] 本発明は、燃料噴射ポンプの逆止弁に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a check valve for a fuel injection pump.

[従来の技術] ディーゼル機関の燃料噴射ポンプでは、第6図に示すよ
うに、プランジャにより燃料が圧縮される圧縮室は逆止
弁(以下、デリバリバルブともいう)及び吐出管路を順
次介してノズルに連結されている。このデリバリバルブ
(第6図参照)の吐出孔200を開閉する吐出孔遮断体
300には、圧縮室側空間Bと吐出管路側空間Aとを連
通ずる戻り孔400が貫設されており、この戻り孔40
0は戻り五速断体500により開閉される。すなわち、
吐出孔遮断体300が開いて吐出管路側空間Aへ燃料が
圧入されると、圧力波かノズル(図示せず)を反射点と
して吐出管路(図示せず)を往復する。この反射圧力波
が吐出孔遮断体300で反射するのを防止するために、
吐出孔遮断体300は後動してノズルからの反射圧力波
を減勢し、また、戻り五速断体500は戻り孔400を
開口して反射圧力波を一層減勢させる。これらの減勢に
より反射圧力波が消勢されるとともに、吐出管路の残圧
は回転数によらずほぼ一定となる(第5図の点線参照)
ので、この種のデリバリバルブは、逆止弁(戻り弁)付
き等圧弁型式と呼ばれ、例えば、特開昭60−1193
66.119367.142050号公報に開示されて
いる。
[Prior Art] In a fuel injection pump for a diesel engine, as shown in FIG. connected to the nozzle. A return hole 400 that communicates the compression chamber side space B and the discharge pipe side space A is provided through the discharge hole blocking body 300 that opens and closes the discharge hole 200 of this delivery valve (see FIG. 6). Return hole 40
0 is opened and closed by a five-speed return disconnector 500. That is,
When the discharge hole blocking body 300 is opened and fuel is pressurized into the discharge pipe side space A, pressure waves reciprocate in the discharge pipe (not shown) using the nozzle (not shown) as a reflection point. In order to prevent this reflected pressure wave from being reflected by the discharge hole blocking body 300,
The discharge hole blocker 300 moves backward to reduce the reflected pressure wave from the nozzle, and the return five-speed cutter 500 opens the return hole 400 to further reduce the reflected pressure wave. Due to these deenergizations, the reflected pressure waves are deenergized, and the residual pressure in the discharge pipe becomes almost constant regardless of the rotation speed (see the dotted line in Figure 5).
Therefore, this type of delivery valve is called an equal-pressure valve type with a check valve (return valve).
It is disclosed in the publication No. 66.119367.142050.

特開昭60−119366.7号公報は、吐出孔遮断体
としてポール形状のものを採用してあり、戻り五速断体
を受承する弁座と吐出管路とを吐出孔遮断体に設けた絞
り細孔で連通している。また、特開昭60−14205
0号公報は、吐出孔遮断体として円盤形状ものを採用し
ており、戻り五速断体を受承する弁座と吐出管路とを吐
出孔遮断体に設けた絞り細孔で連通している。
JP-A-60-119366.7 adopts a pole-shaped discharge hole blocking body, and the discharge hole blocking body is provided with a valve seat for receiving a five-speed return disconnection and a discharge pipe line. They communicate through narrow pores. Also, JP-A-60-14205
Publication No. 0 adopts a disc-shaped discharge hole blocker, and the valve seat that receives the return five-speed disconnection and the discharge pipe are communicated through a throttle hole provided in the discharge hole blocker. .

[発明が解決しようとする課題] 上述したように、戻り弁付き等圧弁型式のデリバリバル
ブは、第5図に点線で示すように吐出管路残圧を一定に
制御している。
[Problems to be Solved by the Invention] As described above, the delivery valve of the equal pressure valve type with a return valve controls the discharge pipe residual pressure to be constant, as shown by the dotted line in FIG.

(ブれども、ノズルの孔が近時、−段と縮径されつつあ
り、それとともにノズルからの反射圧力波が上昇する傾
向にある。反射圧力波が上昇すれば吐出孔遮断体のリフ
ト量も増加するが、管内残圧は一定に保たれるため、プ
ランジャの圧送ストロク一定時の燃料噴射量は増加する
(第5図参照)。ガバナにより噴射量を制御する場合で
も、低回転域の上半部で噴1=lIの山が生じてしまう
(第5図参照)。
(Recently, however, the diameter of the nozzle hole has been reduced by -100 degrees, and the reflected pressure wave from the nozzle has also tended to rise. If the reflected pressure wave rises, the amount of lift of the discharge hole blocker increases. However, since the residual pressure in the pipe is kept constant, the fuel injection amount when the plunger's pressure stroke is constant increases (see Figure 5).Even when the injection amount is controlled by a governor, the fuel injection amount in the low rotation range A mountain of spout 1=lI is formed in the upper half (see Figure 5).

この噴射量の増加を防止するために、上記絞り細孔を拡
径したり戻り五速断体の開弁圧力を決定するスプリング
を弱化したりして中回転域の残圧を減少させることも考
えられる。しかし絞り細孔の拡径では全回転域にわたっ
て戻り量(逆流量)か増大してしまうので、特定の中回
転域(ガバナ制御時)における噴射量増加の集中抑制が
できない。すなわち、低回転域における吐出管路残圧が
低下し過ぎ噴射量が不足する。また、スプリングの弱化
は吐出時の燃料リークなど各種不具合を誘発する。
In order to prevent this increase in injection quantity, it is also possible to reduce the residual pressure in the medium rotation range by enlarging the diameter of the throttle pore and weakening the spring that determines the valve opening pressure of the return five-speed cutter. It will be done. However, expanding the diameter of the throttle pores increases the return amount (backflow amount) over the entire rotation range, so it is not possible to intensively suppress the increase in the injection amount in a specific medium rotation range (during governor control). That is, the residual pressure in the discharge pipe in the low rotation range decreases too much and the injection amount becomes insufficient. Additionally, a weakened spring can lead to various problems such as fuel leaks during discharge.

本発明は上記問題に鑑みなされたものであり、その目的
は、回転速度の増加とともに戻り孔の逆流量の著増を可
能として、高回転域にお(ブる噴射量の好ましからざる
増大を抑圧し得る燃料噴射ポンプの逆止弁を提供するこ
とにある。
The present invention was made in view of the above problems, and its purpose is to suppress an undesirable increase in the injection amount in the high rotation range by making it possible to significantly increase the amount of backflow in the return hole as the rotation speed increases. An object of the present invention is to provide a check valve for a fuel injection pump that can be used in a fuel injection pump.

[問題点を解決するための手段] 本発明の燃料噴射ポンプの逆止弁は、 燃料噴射ポンプの圧縮室からノズルに至る吐出管路中に
配設され吐出孔を有する基筒部と、該吐出孔に摺動自在
に挿通され、前記圧縮室圧力の上昇により前記圧縮室と
前記吐出管路とを連通して前記圧縮室の燃料を前記吐出
管路へ吐出する吐出孔遮断体と、 該吐出孔遮断体を所定の付勢力で閉弁方向に付勢して前
記圧縮室圧力の降下時に前記吐出孔を遮断させる吐出圧
設定用の第1スプリングと、前記吐出孔遮断体に貫設さ
れ前記圧縮室と前記吐出管路とを連通する戻り孔と、 該戻り孔に摺動自在に挿通され、前記吐出管路圧力の上
昇により前記圧縮室と前記吐出管路とを連通して前記吐
出管路の燃料を前記圧縮室へ戻す戻り五速断体と、 該戻り五速断体を所定の付勢力で閉弁方向に付勢して前
記吐出管路圧力の降下時に前記戻り孔を遮断させる逆流
圧設定用の第2スプリングと、を備える燃料噴射ポンプ
の逆止弁において、前記戻り五速断体は、前記吐出孔遮
断体に形成された弁座面に当接可能な遮断部と、前記遮
断部に対し別設され前記バルブリフト量の増大とともに
戻り孔の流体抵抗を低下させる絞り部とを具備している
ことを特徴としている。
[Means for Solving the Problems] A check valve for a fuel injection pump according to the present invention comprises: a base cylindrical portion having a discharge hole disposed in a discharge pipe leading from a compression chamber to a nozzle of the fuel injection pump; a discharge hole blocking body that is slidably inserted into the discharge hole and communicates the compression chamber and the discharge pipe line by increasing the pressure in the compression chamber and discharges the fuel in the compression chamber to the discharge pipe line; a first spring for setting a discharge pressure that biases the discharge hole blocking body in the valve closing direction with a predetermined biasing force to shut off the discharge hole when the pressure in the compression chamber drops; and a first spring that extends through the discharge hole blocking body; a return hole that communicates between the compression chamber and the discharge pipe; and a return hole that is slidably inserted into the return hole and that communicates the compression chamber and the discharge pipe with an increase in the pressure of the discharge pipe to cause the discharge to be discharged. a return five-speed disconnector that returns fuel in the pipe line to the compression chamber; and a reverse flow that biases the return five-speed disconnector in the valve closing direction with a predetermined biasing force to shut off the return hole when the discharge pipe pressure decreases. In the check valve for a fuel injection pump, the check valve includes a second spring for pressure setting, and the five-speed return disconnection member includes a shutoff portion that can come into contact with a valve seat surface formed in the discharge hole shutoff body, and a second spring for setting the pressure. The present invention is characterized in that it includes a constriction part that is separately provided to the valve lift and reduces the fluid resistance of the return hole as the valve lift increases.

1作用及び効果] 本発明の燃料噴射ポンプの逆止弁は、戻り五速断体が、
遮断部に対し別設されバルブリフト量の増大とともに戻
り孔の流体抵抗を低下させる絞り部を具備している。
1 Actions and Effects] The check valve of the fuel injection pump of the present invention has a five-speed return disconnection,
A constriction part is provided separately from the shutoff part and reduces the fluid resistance of the return hole as the valve lift increases.

したがって、バルブリフト量が増大する高回転域におい
て戻り孔の流体抵抗が低下するので、吐出管路から圧縮
室側への戻り量(逆流量)が増大し、それにより高回転
域における吐出管路の残圧が低下する。
Therefore, in the high rotation range where the valve lift amount increases, the fluid resistance of the return hole decreases, so the amount of return from the discharge pipe to the compression chamber side (reverse flow rate) increases, and as a result, the flow rate of the discharge pipe in the high rotation range increases. The residual pressure decreases.

その結果、高回転域において吐出圧力波が増強されても
吐出管路残圧がもともと低いので、それほど燃料噴射量
が増加することがない。
As a result, even if the discharge pressure wave is strengthened in the high rotation range, the residual pressure in the discharge pipe is originally low, so the fuel injection amount does not increase significantly.

またそれに伴ってガバナ制御を強化しなくてもよく、ガ
バナ制御が容易となる。
Further, there is no need to strengthen the governor control accordingly, and the governor control becomes easy.

また、回転増加により上記反射圧力波が強大となっても
、それによりバルブリフト量が増加して戻り量が急増す
るので、戻り五速断体で再反射してノズルに達する再反
射圧力波を消勢して、ノズルの後噴射を防止することが
できる。
In addition, even if the reflected pressure waves become stronger due to increased rotation, this will increase the valve lift amount and the return amount will rapidly increase, so the five-speed return section will eliminate the re-reflected pressure waves that are re-reflected and reach the nozzle. This can prevent the nozzle from spraying afterward.

[実施例] 本発明の燃料噴射ポンプの逆上弁の一実施例を第1図の
要部拡大断面図に基づいて説明する。
[Embodiment] An embodiment of a reverse valve for a fuel injection pump according to the present invention will be described based on an enlarged cross-sectional view of a main part in FIG.

第1図は燃料噴射ポンプの逆止弁(デリバリバルブ)の
縦断面を示す。
FIG. 1 shows a longitudinal section of a check valve (delivery valve) of a fuel injection pump.

このデリバリバルブは燃料噴射ポンプ(図示せず)の圧
縮室(図示せず)と、内燃機関(図示せず)のノズルを
終端末とする吐出管路(図示せず)との間に設【ブられ
ている。
This delivery valve is installed between a compression chamber (not shown) of a fuel injection pump (not shown) and a discharge line (not shown) that terminates in a nozzle of an internal combustion engine (not shown). It is blocked.

このデリバリバルブは燃料噴射ポンプ(図示せず)のケ
ーシングく図示せず)に螺入される基筒部1を有し、基
筒部1に貫孔された吐出孔10に円筒形状の吐出孔遮断
体2が摺動自在に挿通されている。吐出孔遮断体2の頂
部(図中上部)21外周には鍔部22が設けられ、鍔部
22の下面22a及び吐出孔10の上端縁には、吐出孔
遮断体2の下降とともに互いに密接可能な切頭円錐面形
状の斜面(弁面)22b、斜面(弁座面)12bが形成
されている。鍔部22を除く吐出孔遮断体2の外周面に
は軸心と平行方向に4本の油溝23が凹設されており、
油溝23は所定位置で遮断部24により遮断されている
This delivery valve has a base cylinder part 1 that is screwed into a casing of a fuel injection pump (not shown), and has a cylindrical discharge hole in a discharge hole 10 penetrated through the base cylinder part 1. A blocking body 2 is slidably inserted therethrough. A flange 22 is provided on the outer periphery of the top (upper part in the figure) 21 of the discharge hole blocker 2, and the lower surface 22a of the flange 22 and the upper edge of the discharge hole 10 can be brought into close contact with each other as the discharge hole blocker 2 descends. A slope (valve surface) 22b and a slope (valve seat surface) 12b are formed in the shape of a truncated conical surface. Four oil grooves 23 are recessed in the outer peripheral surface of the discharge hole blocking body 2 excluding the flange 22 in a direction parallel to the axis.
The oil groove 23 is blocked by a blocking portion 24 at a predetermined position.

吐出孔遮断体2の上端面29は吐出圧設定用の第1スプ
リング6により所定の付勢力で閉弁方向(図中下方)に
付勢されており、第1スプリング6の基端(図示せず)
は燃料ポンプ(図示せず)のケーシング(図示せず)に
担持されている。
The upper end surface 29 of the discharge hole blocking body 2 is biased in the valve closing direction (downward in the figure) with a predetermined biasing force by the first spring 6 for setting the discharge pressure. figure)
is carried by a casing (not shown) of a fuel pump (not shown).

吐出孔遮断体2の中央には軸心に沿って戻り孔25が貫
孔されており、戻り孔25は吐出管路側空間Aと圧縮室
側空間Bとを連通している。戻り孔25の上孔部25a
は径小、戻り孔25の下孔部25bは径大に形成されて
あり、戻り孔25の内周面は上孔部25aと下孔部25
bとの境界部において切頭円錐面形状の傾斜面(弁座面
)25Cとなっている。
A return hole 25 is formed through the center of the discharge hole blocker 2 along the axis, and the return hole 25 communicates the discharge pipe side space A and the compression chamber side space B. Upper hole portion 25a of return hole 25
is formed to have a small diameter, and the lower hole portion 25b of the return hole 25 is formed to have a larger diameter.
At the boundary with b, there is an inclined surface (valve seat surface) 25C having a truncated conical shape.

戻り孔25には軸心と直交する横断面が円形の戻り五速
断体3が挿通されてあり、戻り五速断体3は径大な厚肉
円盤形状の基部(本発明でいう遮断部>38と、基部3
aの上端面31に基部3aと同心に突設された径小な絞
り部3bとからなる。
A five-speed return section 3 having a circular cross section perpendicular to the axis is inserted into the return hole 25. and base 3
It consists of a constricted portion 3b with a small diameter that protrudes from the upper end surface 31 of the base portion 3a and concentrically with the base portion 3a.

基部3aの外周面32には、それぞれ下孔部25bの内
周面に摺動自在に接する4個のガイド39が設けられて
いる。基部3aの上端面31と外周面32との間には切
頭円錐面形状の傾斜面(弁面)33が設けられている。
Four guides 39 are provided on the outer circumferential surface 32 of the base portion 3a, each slidingly contacting the inner circumferential surface of the lower hole portion 25b. A truncated conical inclined surface (valve surface) 33 is provided between the upper end surface 31 and the outer peripheral surface 32 of the base portion 3a.

また、絞り部3bは基部3aから軸心に沿って立設され
る比較的径大な径大絞り部34と、径大絞り部34から
軸心に沿って立設される比較的径小な径小絞り部35と
からなり、径大絞り部34と径小絞り部35との間に切
頭円錐面が設けられている。
The constricted portion 3b includes a relatively large diameter constricted portion 34 extending upright from the base 3a along the axis, and a relatively small diameter constricted portion 34 upright from the large diameter constricted portion 34 along the axis. A truncated conical surface is provided between the large diameter throttle part 34 and the small diameter throttle part 35.

戻り五速断体3の下端面37は、戻り孔25中に装入さ
れた逆流圧設定用の第2スプリング4により図中上方に
付勢され、第2スプリング4の下端は、戻り孔25の下
側開口部に圧入された貫通孔51付の圧入体5により担
持されている。
The lower end surface 37 of the five-speed return section 3 is biased upward in the figure by the second spring 4 for setting backflow pressure inserted into the return hole 25. It is supported by a press-fit body 5 with a through hole 51 press-fitted into the lower opening.

上記第2スプリング4の付勢により戻り五速断体3の傾
斜面(弁面)33と吐出孔遮断体2の傾斜面(弁座面)
25Cとは密接し、戻り孔25の上孔部25aと下孔部
25bとを液通不能に遮断している。
The inclined surface (valve surface) 33 of the five-speed section 3 and the inclined surface (valve seat surface) of the discharge hole blocking body 2 return due to the bias of the second spring 4.
25C, and blocks the upper hole part 25a and lower hole part 25b of the return hole 25 so that liquid cannot flow through them.

戻り五速断体3の基部3aの外周面32と、この基部3
aに対向する戻り孔25の下孔部25bの内周面との間
の間隙は充分広く(この実施例ではQ、5mm程度に)
設定されている。
The outer circumferential surface 32 of the base 3a of the five-speed return section 3, and the base 3
The gap between the inner circumferential surface of the lower hole portion 25b of the return hole 25 facing the point a is sufficiently wide (in this embodiment, Q is approximately 5 mm).
It is set.

戻り五速断体3の径大絞り部34の外周面と、この径大
絞り部34に対向する戻り孔25の上孔部25aの内周
面との間の間隙部d1はこの戻り孔25の戻り量(逆流
@)を調節する第1のオリフィスとなっており、微小(
この実施例では20〜30μ程度)に設定されている。
A gap d1 between the outer circumferential surface of the large-diameter constricted portion 34 of the five-speed return section 3 and the inner circumferential surface of the upper hole portion 25a of the return hole 25 facing the large-diameter constricted portion 34 is defined by the This is the first orifice that adjusts the return amount (backflow @), and it is
In this embodiment, it is set to about 20 to 30μ).

戻り五速断体3の径小絞り部35の外周面と、この径小
絞り部35に対向する戻り孔25の上孔部25aの内周
面との間の間隙部d2はこの戻り孔25の戻り量(逆流
量)を調節する第2のオリフィスとなっており、間隙d
1より所定量だけ拡大(この実施例では80〜100μ
m程度)されている。
A gap d2 between the outer circumferential surface of the small diameter constricted portion 35 of the five-speed return section 3 and the inner circumferential surface of the upper hole portion 25a of the return hole 25 facing the small diameter constricted portion 35 is the gap d2 of the return hole 25. This is the second orifice that adjusts the return amount (backflow amount), and the gap d
1 by a predetermined amount (in this example, 80 to 100μ)
m).

以下、このデリバリバルブの動作を説明する。The operation of this delivery valve will be explained below.

プランジャ(図示せず)の押動により圧縮室く図示せず
)が加圧されると、この圧縮室に連通する戻り孔10の
圧縮室側空間Bの圧力が上昇し、第1スプリング6に抗
して吐出孔遮断体2を上方に付勢し、その結果、遮断部
24の下端が斜面(弁座面)12bの下縁より上昇し、
油溝23を経由して上記両者の間隙から吐出管路側空間
Aに燃料か吐出される。
When the compression chamber (not shown) is pressurized by pushing the plunger (not shown), the pressure in the compression chamber side space B of the return hole 10 communicating with the compression chamber increases, and the first spring 6 The discharge hole blocking body 2 is urged upward against the force, and as a result, the lower end of the blocking portion 24 rises above the lower edge of the slope (valve seat surface) 12b,
Fuel is discharged from the gap between the two through the oil groove 23 into the discharge pipe side space A.

プランジャ(図示せず)による圧縮室(図示せず)の加
圧が終了すると、戻り孔10の圧縮室側空間Bの圧力が
低下し、第1スプリング6が吐出孔遮断体2を下方に付
勢し、その結果、遮断部24の下端が斜面(弁座面)1
2bの下縁より下降し、吐出管路側空間Aが圧縮室側空
間Bから遮断される。その後も続く吐出孔遮断体2の不
動により吐出管路側空間Aの容積が拡大され、ノズル(
図示せず)からの反射圧力波が吐出孔遮断体2の上端面
29で反射する際の再反射が減殺され、また吐出管路残
圧が減衰される。
When the compression chamber (not shown) is pressurized by the plunger (not shown), the pressure in the compression chamber side space B of the return hole 10 decreases, and the first spring 6 pushes the discharge hole blocker 2 downward. As a result, the lower end of the shutoff part 24 becomes the slope (valve seat surface) 1
It descends from the lower edge of 2b, and the discharge pipe side space A is cut off from the compression chamber side space B. As the discharge hole blocking body 2 continues to remain stationary, the volume of the discharge pipe side space A is expanded, and the nozzle (
Re-reflection when the reflected pressure wave from the discharge hole blocker 2 (not shown) is reflected by the upper end surface 29 of the discharge hole blocking body 2 is reduced, and the residual pressure in the discharge pipe is attenuated.

また、上記反射圧力波は戻り孔25の上孔部25aに侵
入し、第2スプリング4に抗して戻り五速断体3を下方
に押動させる。この下動により、戻り五速断体3の傾斜
面(弁面)33は傾斜面(弁座面)25Cから離れ、吐
出管路側空間Aの燃料が圧縮室側空間Bへ戻る(逆流す
る)。
Further, the reflected pressure wave enters the upper hole portion 25a of the return hole 25 and pushes the five-speed return section 3 downward against the second spring 4. Due to this downward movement, the inclined surface (valve surface) 33 of the five-speed return section 3 separates from the inclined surface (valve seat surface) 25C, and the fuel in the discharge pipe side space A returns to the compression chamber side space B (flows backward).

この逆流量は戻り五速断体3の絞り部3bのバルブリフ
ト量の変動に応じて著しく変化する。すなわち、戻り五
速断体3の径大絞り部34の外周面と戻り孔25の上孔
部25aの内周面との間の間隙部d1が存在する内は、
戻り孔25の戻り量(逆流量)はほぼこの間隙部d1に
より決定され、バルブリフト量の増大にしたがって間隙
部d1の軸心と平行な方向への平均長が短縮する分だけ
戻り量が増加する。
This backflow amount changes significantly in accordance with fluctuations in the valve lift amount of the throttle portion 3b of the five-speed return section 3. That is, while there is a gap d1 between the outer circumferential surface of the large diameter constricted portion 34 of the five-speed return section 3 and the inner circumferential surface of the upper hole portion 25a of the return hole 25,
The return amount (backflow amount) of the return hole 25 is almost determined by the gap d1, and as the valve lift increases, the return amount increases by the amount that the average length of the gap d1 in the direction parallel to the axis is shortened. do.

更にバルブリフト量が増大して戻り五速断体3の径大絞
り部34が戻り孔25の上孔部25aから離脱し、上記
間隙部d1が消滅すると、戻り五速断体3の径小絞り部
35の外周面と戻り孔25の上孔部25aの内周面との
間の間隙部d2か、戻り孔25の戻り量を決定するよう
になる。そして、この間隙部d2が間隙部d1より拡径
されているために戻り量は急増する。
When the valve lift amount further increases and the large-diameter constricted portion 34 of the five-speed return section 3 separates from the upper hole section 25a of the return hole 25, and the gap d1 disappears, the small-diameter constricted section of the five-speed return section 3 separates from the upper hole 25a of the return hole 25. The amount of return of the return hole 25 is determined by the gap d2 between the outer peripheral surface of the return hole 35 and the inner peripheral surface of the upper hole portion 25a of the return hole 25. Since the gap d2 has a larger diameter than the gap d1, the amount of return increases rapidly.

したがってこの実施例のデリバリバルブを用いた場合、
第5図に示すように、回転速度の上昇によりバルブリフ
ト量(戻り弁を構成する戻り孔遮断体3の下動量)が増
加すると、間隙部d2が戻り聞を決定するようになるた
めに戻り量が急増し、それにより吐出管路残圧が回転増
加とともに急減する。そのために、圧送ストローク一定
の場合における噴射量の急増を抑制することができ、ま
た、カバナ付きの噴射ポンプの場合には低速度域の上半
部における噴射量の増加を防止することができ、結局、
燃料噴射量の制御性を向上することができる。
Therefore, when using the delivery valve of this embodiment,
As shown in FIG. 5, when the amount of valve lift (the amount of downward movement of the return hole blocker 3 constituting the return valve) increases due to an increase in the rotational speed, the gap d2 comes to determine the return distance. The amount increases rapidly, and as a result, the residual pressure in the discharge pipe decreases rapidly as the rotation increases. Therefore, it is possible to suppress a sudden increase in the injection amount when the pumping stroke is constant, and in the case of an injection pump with a cabana, it is possible to prevent an increase in the injection amount in the upper half of the low speed range. in the end,
Controllability of fuel injection amount can be improved.

また、この実施例では間隙部d1、d2がともに円筒形
状に形成されているので、戻り五速断体3の下動により
間隙部di、d2の軸心と直交する断面積が変化しにく
く、戻り量変化を所望レベルに安定化することができる
In addition, in this embodiment, since the gaps d1 and d2 are both formed in a cylindrical shape, the cross-sectional area perpendicular to the axis of the gaps di and d2 is unlikely to change due to the downward movement of the five-speed return section 3, and the return Quantity changes can be stabilized at desired levels.

以下に、本発明の他の変形態様を説明する。Other modifications of the present invention will be described below.

第1図の実施例において、更にバルブリフト量が増加す
ると間隙d2も消滅して更に戻り量を増加することがで
きる。
In the embodiment shown in FIG. 1, when the valve lift amount further increases, the gap d2 also disappears, making it possible to further increase the return amount.

第2図のデリバリバルブは第1図の戻り孔25の入口に
固定のオリフィス100を設けたものであり、戻り量の
特性をこのオリフィス100と間隙部d1、d2との総
合流体抵抗により決定することができる。
The delivery valve shown in FIG. 2 is provided with a fixed orifice 100 at the entrance of the return hole 25 shown in FIG. be able to.

第3図のデリバリバルブは第1図の戻り五速断体3の絞
り部3bの径小絞り部35を切頭円錐面形状としたもの
であり、このようにすれば、バルブリフト量の増大とと
もに急激に戻り量を増加することができる。
In the delivery valve shown in FIG. 3, the small-diameter throttle section 35 of the throttle section 3b of the five-speed return section 3 shown in FIG. 1 has a truncated conical shape. The amount of return can be rapidly increased.

第4図のデリバリバルブは第1図の戻り五速断体3の絞
り部3bの径小絞り部35を省略したものであり、この
ようにすれば、バルブリフト量の増大により間隙部d1
が消滅すると同時に更に急激に戻り量を増加することが
できる。
In the delivery valve shown in FIG. 4, the small-diameter constricted portion 35 of the constricted portion 3b of the five-speed return section 3 in FIG. 1 is omitted.
At the same time as disappearing, the amount of return can be increased even more rapidly.

【図面の簡単な説明】[Brief explanation of drawings]

第1図は本発明の燃料噴射ポンプの逆止弁の一実施例を
示すもので、特にデリバリバルブ部分の拡大断面図、第
2図〜第4図はそれぞれ変形態様を示す拡大断面図、第
5図は第1図のデリバリバルブの特性図、第6図は従来
のデリバリバルブの断面図である。 1・・・基筒部 2・・・吐出孔遮断体 3・・・戻り五速断体 3a・・・基部(遮断部) 3b・・・絞り部 4−・・第2スプリング 6・・・第1スプリング 10・・・吐出孔 25・・・戻り孔
FIG. 1 shows an embodiment of a check valve for a fuel injection pump according to the present invention, in particular, an enlarged cross-sectional view of the delivery valve part, and FIGS. 2 to 4 are enlarged cross-sectional views showing modified forms, respectively. FIG. 5 is a characteristic diagram of the delivery valve shown in FIG. 1, and FIG. 6 is a sectional view of the conventional delivery valve. 1... Base cylinder part 2... Discharge hole blocking body 3... Return five-speed section 3a... Base (blocking part) 3b... Throttle part 4-... Second spring 6... No. 1 Spring 10...Discharge hole 25...Return hole

Claims (5)

【特許請求の範囲】[Claims] (1)燃料噴射ポンプの圧縮室からノズルに至る吐出管
路中に配設され吐出孔を有する基筒部と、該吐出孔に摺
動自在に挿通され、前記圧縮室圧力の上昇により前記圧
縮室と前記吐出管路とを連通して前記圧縮室の燃料を前
記吐出管路へ吐出する吐出孔遮断体と、 該吐出孔遮断体を所定の付勢力で閉弁方向に付勢して前
記圧縮室圧力の降下時に前記吐出孔を遮断させる吐出圧
設定用の第1スプリングと、前記吐出孔遮断体に貫設さ
れ前記圧縮室と前記吐出管路とを連通する戻り孔と、 該戻り孔に摺動自在に挿通され、前記吐出管路圧力の上
昇により前記圧縮室と前記吐出管路とを連通して前記吐
出管路の燃料を前記圧縮室へ戻す戻り孔遮断体と、 該戻り孔遮断体を所定の付勢力で閉弁方向に付勢して前
記吐出管路圧力の降下時に前記戻り孔を遮断させる逆流
圧設定用の第2スプリングと、を備える燃料噴射ポンプ
の逆止弁において、前記戻り孔遮断体は、前記吐出孔遮
断体に形成された弁座面に当接可能な遮断部と、前記遮
断部に対し別設され前記戻り孔遮断体のバルブリフト量
の増大とともに戻り孔の流体抵抗を低下させる絞り部と
を具備していることを特徴とする燃料噴射ポンプの逆止
弁。
(1) A base cylinder part disposed in a discharge pipe line leading from a compression chamber to a nozzle of a fuel injection pump and having a discharge hole; a discharge hole blocking body that communicates between the chamber and the discharge pipe line and discharges the fuel in the compression chamber to the discharge pipe line; a first spring for setting a discharge pressure that shuts off the discharge hole when the compression chamber pressure drops; a return hole that extends through the discharge hole blocking body and communicates the compression chamber and the discharge pipe line; a return hole blocker that is slidably inserted into the discharge pipe and communicates the compression chamber and the discharge pipe with an increase in the pressure of the discharge pipe to return fuel in the discharge pipe to the compression chamber; A check valve for a fuel injection pump, comprising: a second spring for setting backflow pressure that biases a blocking body in a valve closing direction with a predetermined biasing force to shut off the return hole when the discharge pipe pressure decreases. , the return hole blocking body includes a blocking portion that can come into contact with a valve seat surface formed on the discharge hole blocking body, and a blocking portion that is separately provided to the blocking portion and that returns as the valve lift amount of the return hole blocking body increases. 1. A check valve for a fuel injection pump, comprising: a constriction portion that reduces fluid resistance in a hole.
(2)前記戻り孔の内周面と前記絞り部の前記外周面と
の間に形成される絞り間隙部の平均断面積は、前記戻り
孔遮断体のバルブリフト量の増加により増大するもので
ある請求項1記載の燃料噴射ポンプの逆止弁。
(2) The average cross-sectional area of the throttle gap formed between the inner circumferential surface of the return hole and the outer circumferential surface of the throttle section increases as the valve lift amount of the return hole blocker increases. A check valve for a fuel injection pump according to claim 1.
(3)前記戻り孔の内周面と前記絞り部の前記外周面と
の間に形成される絞り間隙部の平均通路長は、前記戻り
孔遮断体のバルブリフト量の増加により減少するもので
ある請求項1記載の燃料噴射ポンプの逆止弁。
(3) The average passage length of the throttle gap formed between the inner circumferential surface of the return hole and the outer circumferential surface of the throttle section decreases as the valve lift amount of the return hole blocker increases. A check valve for a fuel injection pump according to claim 1.
(4)前記絞り部は、円筒面形状あるいは円錐形状ある
いは切頭円錐面形状あるいはこれらを組合せた形状の外
周面を有する請求項1記載の燃料噴射ポンプの逆止弁。
(4) The check valve for a fuel injection pump according to claim 1, wherein the throttle portion has an outer peripheral surface having a cylindrical shape, a conical shape, a truncated conical shape, or a combination thereof.
(5)前記絞り部は、前記吐出管路側に位置するより径
小な径小絞り部と、前記圧縮室側に位置する径大な径大
絞り部とを備える請求項3記載の燃料噴射ポンプの逆止
弁。
(5) The fuel injection pump according to claim 3, wherein the throttle section includes a small diameter throttle section located on the discharge pipe side and a large diameter throttle section located on the compression chamber side. check valve.
JP11394390A 1990-04-27 1990-04-27 Check valve of fuel injection pump Pending JPH0412166A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11394390A JPH0412166A (en) 1990-04-27 1990-04-27 Check valve of fuel injection pump

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11394390A JPH0412166A (en) 1990-04-27 1990-04-27 Check valve of fuel injection pump

Publications (1)

Publication Number Publication Date
JPH0412166A true JPH0412166A (en) 1992-01-16

Family

ID=14625088

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11394390A Pending JPH0412166A (en) 1990-04-27 1990-04-27 Check valve of fuel injection pump

Country Status (1)

Country Link
JP (1) JPH0412166A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007332795A (en) * 2006-06-12 2007-12-27 Toyota Motor Corp Fuel pump and fuel supply system
JP2009108847A (en) * 2007-10-12 2009-05-21 Nippon Soken Inc High-pressure fuel pump
US7891338B2 (en) * 2004-06-30 2011-02-22 C.R.F. Societa Consortile Per Azioni Device for regulating pressure/flow in an internal combustion engine fuel injection system
JP2012052464A (en) * 2010-09-01 2012-03-15 Nippon Soken Inc Constant residual pressure valve
US8206131B2 (en) 2007-10-12 2012-06-26 Nippon Soken, Inc. Fuel pump

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7891338B2 (en) * 2004-06-30 2011-02-22 C.R.F. Societa Consortile Per Azioni Device for regulating pressure/flow in an internal combustion engine fuel injection system
JP2007332795A (en) * 2006-06-12 2007-12-27 Toyota Motor Corp Fuel pump and fuel supply system
JP2009108847A (en) * 2007-10-12 2009-05-21 Nippon Soken Inc High-pressure fuel pump
JP2010019263A (en) * 2007-10-12 2010-01-28 Nippon Soken Inc High pressure fuel pump
US8206131B2 (en) 2007-10-12 2012-06-26 Nippon Soken, Inc. Fuel pump
US8297941B2 (en) 2007-10-12 2012-10-30 Nippon Soken, Inc. Fuel pump
JP2012052464A (en) * 2010-09-01 2012-03-15 Nippon Soken Inc Constant residual pressure valve

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