JP4495667B2

JP4495667B2 - Fuel injection device

Info

Publication number: JP4495667B2
Application number: JP2005318823A
Authority: JP
Inventors: 徹小川; 雅道田中; 忍佐久間; 賢廣谷
Original assignee: Yanmar Co Ltd
Current assignee: Yanmar Co Ltd
Priority date: 2005-11-01
Filing date: 2005-11-01
Publication date: 2010-07-07
Anticipated expiration: 2025-11-01
Also published as: JP2007127002A

Description

本発明は、燃料噴射ポンプの技術に関する。より詳細には、燃料供給圧力を調整する調圧弁のピストン機構において、逃がし機構を設けた燃料噴射装置の技術に関する。 The present invention relates to a technology of a fuel injection pump. More specifically, the present invention relates to a technology of a fuel injection device provided with a relief mechanism in a piston mechanism of a pressure regulating valve that adjusts a fuel supply pressure.

従来からディーゼルエンジンには、燃焼室内に燃料を噴射するための、燃料噴射装置が付設されており、該燃料噴射装置においては、高圧側の燃料ギャラリと低圧側の燃料タンクとの間に、調圧弁１００が介装されている。該調圧弁１００は、例えば図１２に示すように、嵌通孔１０１ａが形成される調圧弁本体（ホルダー）１０１と、該調圧弁本体１０１の嵌通孔１０１ａ内に摺動自在に嵌挿されるピストン１０２と、該ピストン１０２を摺動方向の一側に付勢するバネ１０３とで構成されている。 Conventionally, a diesel engine has been provided with a fuel injection device for injecting fuel into a combustion chamber. In the fuel injection device, a fuel injection device is arranged between a high-pressure side fuel gallery and a low-pressure side fuel tank. A pressure valve 100 is interposed. For example, as shown in FIG. 12, the pressure regulating valve 100 is slidably fitted into a pressure regulating valve main body (holder) 101 in which a fitting hole 101a is formed, and a fitting hole 101a of the pressure regulating valve main body 101. The piston 102 includes a spring 103 that urges the piston 102 to one side in the sliding direction.

調圧弁本体１０１には、嵌通孔１０１ａ内部と外部を連通する本体孔１０１ｂが形成され、該本体孔１０１ｂはピストン１０２の摺動により開閉される。嵌通孔１０１ａの一端側１０１ｃは、燃料噴射ポンプの高圧側回路である燃料ギャラリに接続されており、本体孔１０１ｂは、低圧側回路である燃料タンクに接続されている。そして、本体孔１０１ｂがピストン１０２により閉じられている場合には、嵌通孔１０１ａの一端側１０１ｃと該本体孔１０１ｂとが分断され、開いている場合には、嵌通孔１０１ａの一端側１０１ｃと該本体孔１０１ｂとが連通するように構成されている。 The pressure regulating valve main body 101 is formed with a main body hole 101 b that communicates the inside and the outside of the fitting hole 101 a, and the main body hole 101 b is opened and closed by sliding of the piston 102. One end side 101c of the fitting hole 101a is connected to a fuel gallery which is a high pressure side circuit of the fuel injection pump, and the main body hole 101b is connected to a fuel tank which is a low pressure side circuit. When the main body hole 101b is closed by the piston 102, the one end side 101c of the fitting hole 101a and the main body hole 101b are divided, and when the main body hole 101b is open, the one end side 101c of the fitting hole 101a. And the body hole 101b communicate with each other.

この本体孔１０１ｂのピストン１０２による開閉は、ピストン１０２の摺動動作により行われ、燃料ギャラリ内の圧力が所定圧力以上となるまでは、ピストン１０２は、バネ１０３により本体孔１０１ｂが閉じる方向に付勢されている。逆に、燃料ギャラリ内の圧力が所定圧力以上となると、該圧力によりバネ１０３の付勢力に抗してピストン１０２が摺動し、本体孔１０１ｂが開いて燃料ギャラリ内の圧力を開放し、該燃料ギャラリ内の内圧を調整するように構成されている。 The opening and closing of the main body hole 101b by the piston 102 is performed by a sliding operation of the piston 102, and the piston 102 is attached in the direction in which the main body hole 101b is closed by the spring 103 until the pressure in the fuel gallery exceeds a predetermined pressure. It is energized. On the contrary, when the pressure in the fuel gallery exceeds a predetermined pressure, the piston 102 slides against the urging force of the spring 103 by the pressure, and the main body hole 101b opens to release the pressure in the fuel gallery. The internal pressure in the fuel gallery is adjusted.

また、調圧弁本体１０１の嵌通孔１０１ａにおける、バネ１０３が収納される空間は、バネ収納室１０１ｄに構成されており、ピストン１０２には、該バネ収納室１０１ｄと嵌通孔１０１ａの一端側１０１ｃとを連通するエア抜き孔１０２ａが形成されている。エア抜き孔１０２ａは小径に形成されており、燃料ギャラリ内に発生する気泡を該エア抜き孔１０２ａから低圧側へ排出するように構成されている。また、エア抜き孔１０２ａからは、常時、燃料ギャラリ内の燃料油が除々に低圧側へ漏出している。尚、調圧弁本体１０１には、バネ収納室１０１ｄ内と低圧側とを連通する連通孔１０１ｅが形成される。 The space in which the spring 103 is accommodated in the fitting hole 101a of the pressure regulating valve main body 101 is configured in the spring accommodating chamber 101d, and the piston 102 has one end side of the spring accommodating chamber 101d and the fitting hole 101a. An air vent hole 102a communicating with 101c is formed. The air vent hole 102a has a small diameter, and is configured to discharge air bubbles generated in the fuel gallery from the air vent hole 102a to the low pressure side. Further, the fuel oil in the fuel gallery gradually leaks out to the low pressure side from the air vent hole 102a at all times. The pressure regulating valve main body 101 is formed with a communication hole 101e that communicates the inside of the spring storage chamber 101d with the low pressure side.

ところで前述した調圧弁を有する、燃料噴射ポンプにおいては、従来からポンプ内に発生するキャビテーション・エロージョン（高速で流れる流体中に発生する気泡が、崩壊するときに発生する衝撃力による材料表面の損傷）を低減させ、ポンプの長寿命化を図ると同時に、ポンプ低回転時の、ハンチングやエンストを防止する対策が検討されてきた。ここで、キャビテーション・エロージョンの発生を低減する為には、調圧弁１００が開く設定圧力をできるだけ高圧に設定し、燃料ギャラリ圧を高圧に保持することが望ましい一方、ハンチングやエンストを防止する為には、逆に燃料ギャラリ圧を低圧に保持することが望ましい為、両者対峙する要望を同時に満足させることが必要となる。 By the way, in the fuel injection pump having the pressure regulating valve described above, cavitation erosion that occurs in the pump conventionally (damage of the material surface due to the impact force generated when the bubbles generated in the fluid flowing at high speed collapse) Measures to prevent hunting and engine stall at the time of low pump rotation have been studied at the same time as reducing pumping and extending pump life. Here, in order to reduce the occurrence of cavitation and erosion, it is desirable to set the set pressure that the pressure regulating valve 100 opens as high as possible and maintain the fuel gallery pressure as high as possible, while preventing hunting and engine stall. On the other hand, since it is desirable to keep the fuel gallery pressure low, it is necessary to satisfy both requirements simultaneously.

上記対策として、ピストンに圧力逃がし用嵌通孔を設けて、ポンプ高回転時の燃料ギャラリ圧の高圧保持と、ポンプ低回転時の燃料ギャラリ圧の低圧保持と、を同時に満足させる技術が公知となっている。即ち、ポンプ低回転時においては、ピストンは閉じているが、前記圧力逃がし用嵌通孔を介して、燃料ギャラリ側（高圧側）と燃料タンク側（低圧側）を連通させ、該燃料ギャラリ内の燃料を低圧側へと漏出させる結果、該燃料ギャラリ圧を低圧に保持することができる。また、ポンプ高回転時においては、ピストンが開くと同時に、圧力逃がし用嵌通孔は閉じるので、圧力損失は発生せず、設定圧力を高圧に設定し、燃料ギャラリ圧を高圧に保持することができる（特許文献１を参照）。
特開２００３−６５１８６号公報 As a measure for the above, a technology is known in which a pressure relief fitting hole is provided in the piston to simultaneously satisfy the high pressure holding of the fuel gallery pressure during high pump rotation and the low pressure holding of the fuel gallery pressure during low pump rotation. It has become. That is, the piston is closed at the time of low pump rotation, but the fuel gallery side (high pressure side) and the fuel tank side (low pressure side) are communicated with each other via the pressure relief fitting hole. As a result, the fuel gallery pressure can be maintained at a low pressure. Also, when the pump is rotating at high speed, the pressure relief fitting hole closes at the same time as the piston opens, so no pressure loss occurs and the set pressure can be set to a high pressure and the fuel gallery pressure can be maintained at a high pressure. Yes (see Patent Document 1).
JP 2003-65186 A

このように、従来の調圧弁を改善し、キャビテーション・エロージョンの減少と、ハンチングやエンストの防止を同時に満足させる技術が提供されているが、実現化に伴う課題は依然に残る。即ち、特許文献１に示す発明においては、ピストンが閉じている状態では、圧力逃がし用嵌通孔は全開状態とし、ピストンがバネ収納室１０１ｄ側へ摺動するに従い、該圧力逃がし用嵌通孔を徐々に閉塞させ、ピストンが本体孔１０１ｂを開くと同時に、該圧力逃がし用嵌通孔を完全に閉塞させる要件を満足する必要があり、加工および組付けに関する精度の確保が容易でなく、またコストの増加も誘発する。 As described above, there has been provided a technique for improving the conventional pressure regulating valve and simultaneously satisfying the reduction of cavitation erosion and the prevention of hunting and engine stalling, but problems associated with realization still remain. That is, in the invention shown in Patent Document 1, when the piston is closed, the pressure relief fitting hole is fully opened, and as the piston slides toward the spring housing chamber 101d, the pressure relief fitting hole is provided. And the piston opens the main body hole 101b, and at the same time, the requirements for completely closing the pressure relief fitting hole must be satisfied, and it is not easy to ensure the accuracy of processing and assembly. It also induces an increase in cost.

よって、本発明においては、従来の調圧弁を改善する新技術として、ポンプ高回転時の燃料ギャラリ圧の高圧保持と、ポンプ低回転時の燃料ギャラリ圧の低圧保持と、を同時に満足させ、キャビテーション・エロージョンの減少と、ハンチングやエンストの防止を図る技術の提供を課題とする。 Therefore, in the present invention, as a new technology for improving the conventional pressure regulating valve, the high pressure holding of the fuel gallery pressure at the time of high pump rotation and the low pressure holding of the fuel gallery pressure at the time of low pump rotation are satisfied at the same time.・ Provide technologies to reduce erosion and prevent hunting and engine stalls.

本発明の解決しようとする課題は以上の如くであり、次にこの課題を解決するための手段を説明する。 The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

ポンプ本体（１）の内部に複数の燃料噴射ポンプ（１１）を併設し、該複数の燃料噴射ポンプ（１１）が連通する燃料ギャラリ（８）を設け、該燃料噴射ポンプ（１１）を構成するプランジャバレル（２）には、プランジャ（６）の摺動方向と直角方向にバレルポート（７）が穿設し、該バレルポート（７）がポンプ本体（１）に形成された燃料ギャラリ（８）と連通し、該ポンプ本体（１）に、該燃料ギャラリ（８）と外部とを連通させる燃料吸入通路及び燃料排出通路を設け、燃料は、燃料吸入通路より燃料ギャラリ（８）、バレルポート（７）を介してポンプ室（３）内に供給され、逃がし油は、バレルポート（７）、燃料ギャラリ（８）を介して燃料排出通路より燃料タンク側へ排出すべく構成し、高圧側の燃料ギャラリ（８）と低圧側の燃料タンクとの間に、調圧弁（２０）を介装し、該調圧弁（２０）を、調圧弁本体（２１）と、該調圧弁本体（２１）に形成した嵌通孔（２１ａ）に嵌装するピストン（２２）と、該ピストン（２２）を閉じる側に付勢するバネ（２３）より構成し、該調圧弁本体（２１）とピストン（２２）の間における、該ピストンストローク初期部分に逃がし機構を設け、前記逃がし機構はピストン（２２）の端部に、前記嵌通孔（２１ａ）の径を嵌通孔（２１ａ）よりも小径とした段付部（２４）を設け、該段付部（２４）の軸心方向における長さの寸法（イ）は、嵌通孔（２１ａ）に挿入したピストン（２２）が、調圧弁本体（２１）の長手方向中途部に前記嵌通孔（２１ａ）に対して直角方向に開口され、燃料ギャラリ（８）と連通する本体孔（２１ｂ）を閉塞し、該燃料ギャラリ（８）側から圧力を受けない状態の挿入深さの寸法（ロ）より、僅かに短い寸法とし、該ピストン（２２）と嵌通孔（２１ａ）との間に寸法（ハ）の微小掛止部を構成し、該微小掛止部は、該ピストン（２２）の位置規制部としたものである。 A plurality of fuel injection pumps (11) are provided inside the pump body (1), and a fuel gallery (8) through which the plurality of fuel injection pumps (11) communicate with each other is provided to constitute the fuel injection pump (11). A barrel port (7) is formed in the plunger barrel (2) in a direction perpendicular to the sliding direction of the plunger (6), and the barrel port (7) is formed in the fuel body (8) formed in the pump body (1). ), And the pump body (1) is provided with a fuel intake passage and a fuel discharge passage for communicating the fuel gallery (8) and the outside, and fuel is supplied from the fuel intake passage to the fuel gallery (8), barrel port. (7) is supplied into the pump chamber (3), and the release oil is configured to be discharged from the fuel discharge passage to the fuel tank side via the barrel port (7) and the fuel gallery (8). Fuel gallery (8) and low The pressure regulating valve (20) is interposed between the fuel tank on the side, and the pressure regulating valve (20) is formed in the pressure regulating valve main body (21) and the fitting hole (21a) formed in the pressure regulating valve main body (21). ) And a spring (23) that biases the piston (22) toward the closing side, and the piston stroke between the pressure regulating valve body (21) and the piston (22) A relief mechanism is provided in the initial portion, and the relief mechanism is provided with a stepped portion (24) in which the diameter of the fitting hole (21a) is smaller than that of the fitting hole (21a) at the end of the piston (22). The dimension (a) of the length of the stepped portion (24) in the axial direction is such that the piston (22) inserted into the fitting hole (21a) is located in the middle in the longitudinal direction of the pressure regulating valve body (21). A book that opens in a direction perpendicular to the fitting hole (21a) and communicates with the fuel gallery (8). The hole (21b) is closed and is slightly shorter than the insertion depth (b) in a state in which no pressure is received from the fuel gallery (8) side. The piston (22) and the fitting hole (21a) A minute latching portion having a dimension (c) is formed between and a position restricting portion of the piston (22) .

本発明の効果として、以下に示すような効果を奏する。 As effects of the present invention, the following effects can be obtained.

請求項１においては、ポンプ本体（１）の内部に複数の燃料噴射ポンプ（１１）を併設し、該複数の燃料噴射ポンプ（１１）が連通する燃料ギャラリ（８）を設け、該燃料噴射ポンプ（１１）を構成するプランジャバレル（２）には、プランジャ（６）の摺動方向と直角方向にバレルポート（７）が穿設し、該バレルポート（７）がポンプ本体（１）に形成された燃料ギャラリ（８）と連通し、該ポンプ本体（１）に、該燃料ギャラリ（８）と外部とを連通させる燃料吸入通路及び燃料排出通路を設け、燃料は、燃料吸入通路より燃料ギャラリ（８）、バレルポート（７）を介してポンプ室（３）内に供給され、逃がし油は、バレルポート（７）、燃料ギャラリ（８）を介して燃料排出通路より燃料タンク側へ排出すべく構成し、高圧側の燃料ギャラリ（８）と低圧側の燃料タンクとの間に、調圧弁（２０）を介装し、該調圧弁（２０）を、調圧弁本体（２１）と、該調圧弁本体（２１）に形成した嵌通孔（２１ａ）に嵌装するピストン（２２）と、該ピストン（２２）を閉じる側に付勢するバネ（２３）より構成し、該調圧弁本体（２１）とピストン（２２）の間における、該ピストンストローク初期部分に逃がし機構を設けたので、ピストンの摺動初期領域における、燃料ギャラリ内の燃料が、該逃がし機構を介して低圧側へ漏出し、燃料供給圧力（フィード圧力）を低減させる為、プランジャーの追従性が向上し、燃料噴射ポンプの回転数が低回転となるローアイドル運転時の、ハンチングやエンストを防止することができる。
また、燃料噴射ポンプの回転数が高回転となる定格運転時においては、燃料ギャラリ内の圧力は増加し、燃料供給圧力も上昇する為、キャビテーション・エロージョンの発生が抑止され、ポンプ自体の長寿命化に繋がる。 The fuel injection pump according to claim 1, wherein a plurality of fuel injection pumps (11) are provided inside the pump body (1), and a fuel gallery (8) is provided in communication with the plurality of fuel injection pumps (11). A barrel port (7) is formed in the plunger barrel (2) constituting (11) in a direction perpendicular to the sliding direction of the plunger (6), and the barrel port (7) is formed in the pump body (1). The fuel gallery (8) communicates, and the pump body (1) is provided with a fuel intake passage and a fuel discharge passage for communicating the fuel gallery (8) and the outside, and fuel is supplied from the fuel intake passage to the fuel gallery. (8) The oil is supplied into the pump chamber (3) through the barrel port (7), and the release oil is discharged from the fuel discharge passage to the fuel tank side through the barrel port (7) and the fuel gallery (8). Configured on the high pressure side A pressure regulating valve (20) is interposed between the gallery (8) and the fuel tank on the low pressure side, and the pressure regulating valve (20) is formed in the pressure regulating valve body (21) and the pressure regulating valve body (21). A piston (22) that fits into the fitting hole (21a) and a spring (23) that biases the piston (22) toward the closing side, and the pressure regulating valve body (21) and the piston (22) Since the escape mechanism is provided at the initial part of the piston stroke , the fuel in the fuel gallery leaks to the low pressure side through the escape mechanism in the initial sliding region of the piston, and the fuel supply pressure (feed pressure) Therefore, the followability of the plunger is improved, and hunting and engine stall can be prevented during low idle operation where the rotational speed of the fuel injection pump is low.
Also, during rated operation where the number of revolutions of the fuel injection pump is high, the pressure in the fuel gallery increases and the fuel supply pressure also rises, so the occurrence of cavitation and erosion is suppressed, and the pump itself has a long service life. Leads to

また、前記逃がし機構はピストン（２２）の端部に、前記嵌通孔（２１ａ）の径を嵌通孔（２１ａ）よりも小径とした段付部（２４）を設け、該段付部（２４）の軸心方向における長さの寸法（イ）は、嵌通孔（２１ａ）に挿入したピストン（２２）が、調圧弁本体（２１）の長手方向中途部に前記嵌通孔（２１ａ）に対して直角方向に開口され、燃料ギャラリ（８）と連通する本体孔（２１ｂ）を閉塞し、該燃料ギャラリ（８）側から圧力を受けない状態の挿入深さの寸法（ロ）より、僅かに短い寸法とし、該ピストン（２２）と嵌通孔（２１ａ）との間に寸法（ハ）の微小掛止部を構成し、該微小掛止部は、該ピストン（２２）の位置規制部としたので、簡単な構成で逃がし機構が構成でき、安価なコストで燃料噴射ポンプ低回転時の燃料供給圧力を低減することができる。 The relief mechanism is provided with a stepped portion (24) having a diameter of the fitting hole (21a) smaller than that of the fitting hole (21a) at the end of the piston (22). 24) The length (a) in the axial direction of the shaft 24 is such that the piston (22) inserted into the fitting hole (21a) is inserted into the fitting hole (21a) in the longitudinal direction of the pressure regulating valve main body (21). From the dimension (B) of the insertion depth in a state where the body hole (21b) is opened at a right angle to the fuel gallery (8) and communicates with the fuel gallery (8) and no pressure is received from the fuel gallery (8) side. A slightly shorter dimension is formed, and a minute latching part having a dimension (c) is formed between the piston (22) and the fitting hole (21a), and the minute latching part is used to regulate the position of the piston (22). because the parts can mechanism construction relief with a simple configuration, fuel at the fuel injection pump low rotation at a low cost It is possible to reduce the supply pressure.

次に、発明の実施の形態を説明する。 Next, embodiments of the invention will be described.

図１は本発明の一実施例に係る、ポンプ本体の調圧弁の配設部を示す正面図、図２は同じく、調圧弁の配設部を示す平面図、図３は本発明の調圧弁と配設される燃料噴射ポンプを示す側面断面図である。図４は本発明の第一実施例に係る調圧弁の、ピストンが閉じた状態を示す側面断面図である。 1 is a front view showing an arrangement portion of a pressure regulating valve of a pump body according to an embodiment of the present invention, FIG. 2 is a plan view showing the arrangement portion of the pressure regulating valve, and FIG. 3 is a pressure regulating valve of the present invention. It is side surface sectional drawing which shows the fuel-injection pump arrange | positioned. FIG. 4 is a side sectional view showing the pressure regulating valve according to the first embodiment of the present invention in a state where the piston is closed.

図５は本発明の第一実施例に係る調圧弁の、ピストンが開いた状態を示す側面断面図、図６は本発明の一実施例に係る、調圧弁のピストンを斜上方から見た斜視図である。図７は本発明の第一構成例に係る調圧弁の、ピストンが閉じた状態を示す側面断面図、図８は本発明の第一構成例に係る調圧弁の、ピストンが開いた状態を示す側面断面図である。 FIG. 5 is a side sectional view showing a state in which the piston of the pressure regulating valve according to the first embodiment of the present invention is open, and FIG. 6 is a perspective view of the piston of the pressure regulating valve according to one embodiment of the present invention as viewed obliquely from above. FIG. Figure 7 is a first configuration example according regulating valve of the present invention, showing a side sectional view showing a state in which the piston is closed, Figure 8 is a pressure regulating valve according to a first configuration of the present invention, a state in which the piston is open It is side surface sectional drawing.

図９は本発明の第一構成例に係る調圧弁の、ホルダーを示した側面断面図である。図１０は従来の調圧弁を用いた場合と、本発明に係る調圧弁を用いた場合の、燃料噴射ポンプ回転数の低速領域における、燃料供給圧力の差異を示す図である。図１１は調圧弁の開口面積と、ピストンの摺動量との関係を示す図、図１２は従来の調圧弁に係る、ピストンが閉じた状態を示す側面断面図である。 FIG. 9 is a side sectional view showing the holder of the pressure regulating valve according to the first configuration example of the present invention. FIG. 10 is a diagram showing a difference in fuel supply pressure in the low speed region of the fuel injection pump rotation speed when the conventional pressure regulating valve is used and when the pressure regulating valve according to the present invention is used. FIG. 11 is a view showing the relationship between the opening area of the pressure regulating valve and the sliding amount of the piston, and FIG. 12 is a side sectional view showing a state where the piston is closed according to a conventional pressure regulating valve.

本発明の実施例１を、以下に説明する。 Example 1 of the present invention will be described below.

［全体構成］
図１及び図２に示すように、本発明の調圧弁２０は、ポンプ本体１の上面部に、複数の燃料噴射ポンプ１１と並設され、該ポンプ本体１内部において、その一端を燃料ギャラリ８と連通する。燃料噴射ポンプ１１は、図３に示すように、ポンプ本体１に内嵌されたプランジャバレル２内にポンプ室３が形成され、プランジャバレル２の上部に取り付けられたデリベリホルダー４内にポンプ室３に連通するデリベリ油路５が穿設されていて、ポンプ室３内において、プランジャ６が往復摺動することによって、デリベリ油路５を介して、燃料噴射バルブに燃料を圧送するものである。 [overall structure]
As shown in FIGS. 1 and 2, the pressure regulating valve 20 according to the present invention is arranged in parallel with a plurality of fuel injection pumps 11 on the upper surface of the pump body 1, and one end of the pressure regulating valve 20 is disposed in the fuel gallery 8 inside the pump body 1. Communicate with. As shown in FIG. 3, the fuel injection pump 11 has a pump chamber 3 formed in a plunger barrel 2 fitted in the pump body 1, and a pump chamber in a delivery holder 4 attached to the top of the plunger barrel 2. A delivery oil passage 5 communicating with the fuel delivery valve 3 is formed, and the plunger 6 reciprocates and slides in the pump chamber 3 to pump the fuel to the fuel injection valve via the delivery oil passage 5. .

プランジャバレル２には、プランジャ６の摺動方向と直角方向にバレルポート７・７が穿設され、このバレルポート７・７がポンプ本体１に形成された燃料ギャラリ８に連通している。ポンプ本体１には、燃料ギャラリ８と外部とを連通させる燃料吸入通路（図示せず）及び燃料排出通路（図示せず）が設けられており燃料は、燃料吸入通路より燃料ギャラリ８、バレルポート７を介してポンプ室３内に供給され、また逃がし油をバレルポート７、燃料ギャラリ８を介して燃料排出通路より燃料タンク（図示せず）側へ排出するようになっている。燃料ギャラリ８に連通する燃料排出通路と燃料タンクとの間には、調圧弁（図示せず）が介装されており、ポンプ本体１に装着されている。 In the plunger barrel 2, barrel ports 7 are formed in a direction perpendicular to the sliding direction of the plunger 6, and the barrel ports 7 are communicated with a fuel gallery 8 formed in the pump body 1. The pump body 1 is provided with a fuel intake passage (not shown) and a fuel discharge passage (not shown) for communicating the fuel gallery 8 with the outside, and fuel is supplied from the fuel intake passage to the fuel gallery 8 and the barrel port. 7 is supplied into the pump chamber 3 through the barrel port 7 and the fuel gallery 8 and is discharged from the fuel discharge passage to the fuel tank (not shown) side. A pressure regulating valve (not shown) is interposed between the fuel discharge passage communicating with the fuel gallery 8 and the fuel tank, and is attached to the pump body 1.

また、燃料ギャラリ８への燃料の供給は、燃料噴射ポンプに付設される燃料供給ポンプ（図示せず。）により行われ、該燃料供給ポンプは、エンジン回転数により燃料吐出量が変化するように構成されている。即ち、エンジン回転数が低いときには吐出量が少なく、エンジン回転数が高いときには吐出量が多くなるように構成されている。 The fuel is supplied to the fuel gallery 8 by a fuel supply pump (not shown) attached to the fuel injection pump, and the fuel supply pump changes the fuel discharge amount according to the engine speed. It is configured. That is, the discharge amount is small when the engine speed is low, and the discharge amount is large when the engine speed is high.

［調圧弁］
次に、調圧弁２０の構成について説明する（尚、本発明の実施例１に係る調圧弁２０は、ピストンの一部形状に関して、従来の調圧弁１００と相違する）。図４及び図５に示すように、調圧弁２０は、嵌通孔２１ａが軸心部に形成される調圧弁本体２１と、該調圧弁本体２１の嵌通孔２１ａ内に摺動自在に嵌装されるピストン２２と、該ピストン２２を摺動方向の一側に付勢するバネ２３とで構成される。 [Pressure control valve]
Next, the configuration of the pressure regulating valve 20 will be described (note that the pressure regulating valve 20 according to the first embodiment of the present invention is different from the conventional pressure regulating valve 100 with respect to a partial shape of the piston). As shown in FIGS. 4 and 5, the pressure regulating valve 20 is slidably fitted into the pressure regulating valve main body 21 in which the fitting hole 21 a is formed in the shaft center portion, and the fitting hole 21 a of the pressure regulating valve main body 21. It comprises a piston 22 to be mounted and a spring 23 that biases the piston 22 to one side in the sliding direction.

調圧弁本体（ホルダー）２１には、嵌通孔２１ａ内と外部とを連通する本体孔２１ｂが嵌通孔２１ａと直角方向に調圧弁本体２１の長手方向中途部に開口され、該本体孔２１ｂはピストン２２の摺動により開閉される。調圧弁本体２１の嵌通孔２１ａの一端は調整ネジ２５または栓により閉じられ、ピストン２２とこの閉じられた空間内にバネ２３が収納されてバネ収納室２１ｄとしている。嵌通孔２１ａの一端側２１ｃは、燃料噴射ポンプの高圧側回路である燃料ギャラリ８と連通する、燃料排出通路に接続されており、本体孔２１ｂは、低圧側（余剰戻し側）回路である燃料タンクに接続されている。 In the pressure regulating valve main body (holder) 21, a main body hole 21b that communicates the inside of the fitting hole 21a with the outside is opened at a midway in the longitudinal direction of the pressure regulating valve main body 21 in a direction perpendicular to the fitting hole 21a. Is opened and closed by sliding of the piston 22. One end of the fitting hole 21a of the pressure regulating valve main body 21 is closed by an adjusting screw 25 or a stopper, and a spring 23 is accommodated in the piston 22 and the closed space to form a spring accommodating chamber 21d. One end side 21c of the fitting hole 21a is connected to a fuel discharge passage communicating with the fuel gallery 8 which is a high-pressure side circuit of the fuel injection pump, and the main body hole 21b is a low-pressure side (excess return side) circuit. Connected to the fuel tank.

そして、図４に示すように、ピストン２２がバネ２３により付勢されて一端側２１ｃに摺動している場合には、本体孔２１ｂがピストン２２により閉じられ、逆に、図５に示すように、ピストン２２がバネ２３の付勢力に抗してバネ収納室２１ｄ側に摺動すると、本体孔２１ｂがピストン２２により開いて、嵌通孔２１ａの一端側２１ｃと該本体孔２１ｂとが直接連通するように構成されている。 As shown in FIG. 4, when the piston 22 is urged by the spring 23 and slides toward the one end 21c, the main body hole 21b is closed by the piston 22, and conversely, as shown in FIG. When the piston 22 slides toward the spring accommodating chamber 21d against the biasing force of the spring 23, the main body hole 21b is opened by the piston 22, and the one end side 21c of the fitting hole 21a and the main body hole 21b are directly connected. It is configured to communicate.

また、本体孔２１ｂのピストン２２による開閉は、ピストン２２の摺動動作により行われ、燃料ギャラリ内の圧力が所定圧力以上となるまでは、ピストン２２は、バネ２３により本体孔２１ｂが閉じる方向に付勢された状態を保持する。逆に、燃料ギャラリ内の圧力が所定圧力以上になると、該圧力によりバネ２３の付勢力に抗してピストン２２が摺動し、本体孔２１ｂが開いて燃料ギャラリ内の圧力が開放される。これにより、燃料ギャラリ内の圧力がバネ２３により設定される圧力以上とならないように調整される。尚、ピストン２２を押圧するバネ２３の付勢力は、該ピストン２２と対峙して配設する調整ネジ２５を出入することにより、自在に調整可能な機構を有する。そして、本発明では前記調圧弁本体（ホルダー）２１とピストン２２の間における、ピストンストローク初期部分に逃がし機構を設けている。まず、ピストンに逃がし機構を設けた実施例について説明する。 The opening and closing of the main body hole 21b by the piston 22 is performed by a sliding operation of the piston 22, and the piston 22 is moved in a direction in which the main body hole 21b is closed by the spring 23 until the pressure in the fuel gallery exceeds a predetermined pressure. Hold the energized state. On the contrary, when the pressure in the fuel gallery exceeds a predetermined pressure, the piston 22 slides against the urging force of the spring 23 by the pressure, and the main body hole 21b is opened to release the pressure in the fuel gallery. Thus, the pressure in the fuel gallery is adjusted so as not to exceed the pressure set by the spring 23. The urging force of the spring 23 that presses the piston 22 has a mechanism that can be freely adjusted by moving an adjustment screw 25 arranged opposite to the piston 22. In the present invention, a relief mechanism is provided in the initial part of the piston stroke between the pressure regulating valve main body (holder) 21 and the piston 22. First, an embodiment in which a relief mechanism is provided on the piston will be described.

［ピストン］
ピストン２２は、従来型ピストン１０２の燃料ギャラリ側に、外径を設定長さ小径とした段付部２４を設けた形状を有し、その形成範囲（軸心方向における小径部の長さ、つまり、図４に示す、寸法イ）は、嵌通孔２１ａに挿入したピストン２２が燃料ギャラリ側から圧力を受けない状態（非作用時）での挿入深さ（図４に示す、寸法ロ）より、僅かに浅い領域となっている。そして、ピストン２２と嵌通孔２１ａとの微小掛止部（図４に示す、寸法ハ）は、該ピストン２２挿入時の位置規制に利用される。但し、ピストン２２の燃料ギャラリ側外周に、寸法イの範囲で溝を設けたり、すり割を設けたりして段付部を構成することも可能である。 [piston]
The piston 22 has a shape in which a stepped portion 24 having a small outer diameter is provided on the fuel gallery side of the conventional piston 102, and its formation range (the length of the small diameter portion in the axial direction, that is, Dimension (a) shown in FIG. 4 is based on the insertion depth (dimension (b) shown in FIG. 4) in a state where the piston 22 inserted into the fitting hole 21a does not receive pressure from the fuel gallery side (when not acting). It is a slightly shallow area. And the minute latching | locking part (dimension C shown in FIG. 4) of piston 22 and the fitting hole 21a is utilized for position control at the time of piston 22 insertion. However, it is also possible to form a stepped portion by providing a groove or slit in the outer periphery of the piston 22 on the fuel gallery side within the range of dimension A.

ピストン２２がバネ２３により一端側２１ｃ（ストーク始端側）に摺動している状態においては（図４に示す状態）、ピストン２２により本体孔２１ｂが閉じられているが、エア抜き孔２２ａは連通しており、燃料ギャラリ内に発生する気泡及び燃料油が徐々に低圧側へ漏出する。 In the state where the piston 22 is slid to the one end side 21c (Stoke start end side) by the spring 23 (the state shown in FIG. 4), the body hole 21b is closed by the piston 22, but the air vent hole 22a is in communication. Therefore, bubbles and fuel oil generated in the fuel gallery gradually leak to the low pressure side.

この状態から、燃料ギャラリ内の圧力が上昇して、ピストン２２がバネ収納室２１ｄ側（ストロークエンド側）へ摺動する場合、該ピストン２２が前記微小掛止部から脱離した直後から、燃料ギャラリ内の燃料油はピストン２２の段付部２４からも、低圧側へ漏出し始める。そして、ピストン２２の摺動距離が伸長するにつれて、段付部２４における間隙部２１ｆも緩やかに拡大する。 From this state, when the pressure in the fuel gallery rises and the piston 22 slides toward the spring accommodating chamber 21d side (stroke end side), the fuel immediately after the piston 22 is detached from the minute latching portion. The fuel oil in the gallery starts to leak from the stepped portion 24 of the piston 22 to the low pressure side. As the sliding distance of the piston 22 increases, the gap portion 21f in the stepped portion 24 also gradually increases.

燃料ギャラリ内の圧力が更に上昇し、ピストン２２の一側端が嵌通孔２１ａとの挿入部を完全に脱すると、本体孔２１ｂの開口断面積が広がり始め、燃料ギャラリと低圧側との連通部面積は急激に増加する。そして、更にピストン２２は摺動し、図５に示す状態において、本体孔２１ｂは、完全に開口される。 When the pressure in the fuel gallery further rises and one side end of the piston 22 completely disengages the insertion part with the fitting hole 21a, the opening cross-sectional area of the main body hole 21b begins to expand, and the communication between the fuel gallery and the low pressure side begins. Part area increases rapidly. Further, the piston 22 slides, and in the state shown in FIG. 5, the main body hole 21b is completely opened.

以上ように、ピストン２２の摺動領域内において、燃料ギャラリ内の圧力が低圧時の領域と、高圧時の領域とで、燃料ギャラリと低圧部との連通部面積の増加量を変化させる機構を設けることで、低圧領域での燃料供給圧力を、従来調圧弁と比較して、減少させ、且つ、高圧領域での燃料供給圧力を、従来調圧弁と同等に、所定の設定圧力に保持することを可能とする。尚、調圧弁２０における調圧弁本体２１には、バネ収納室２１ｄ内部と外部の低圧側とを連通する連通穴２１ｅが形成されており、ピストン２２がバネ収納室２１ｄ側へ摺動する場合に、該バネ収納室２１ｄ内の燃料が低圧側へ逃げることができるように構成している。これにより、バネ収納室２１ｄ内の燃料がピストン２２の摺動に対する抵抗となることを防止するようにしている。 As described above, in the sliding region of the piston 22, the mechanism for changing the amount of increase in the communication portion area between the fuel gallery and the low pressure portion between the region when the pressure in the fuel gallery is low and the region when the pressure is high. By providing, the fuel supply pressure in the low pressure region is reduced as compared with the conventional pressure regulating valve, and the fuel supply pressure in the high pressure region is maintained at a predetermined set pressure equivalent to the conventional pressure regulating valve. Is possible. The pressure regulating valve main body 21 of the pressure regulating valve 20 is formed with a communication hole 21e that communicates the inside of the spring storage chamber 21d with the low pressure side on the outside, and when the piston 22 slides toward the spring storage chamber 21d. The fuel in the spring storage chamber 21d is configured to escape to the low pressure side. This prevents the fuel in the spring storage chamber 21d from becoming a resistance against the sliding of the piston 22.

次に、燃料供給ポンプ運転時における、調圧弁２０の具体的動作を説明する。上述のように構成される調圧弁２０は、エンジン停止時には、ピストン２２は、一端側２１ｃに摺動しており、本体孔２１ｂは該ピストン２２によって完全に閉口された状態にある（図４に示す状態。）。この状態においては、該ピストンに嵌通されたエア抜き孔２２ａのみを通じて、高圧側と低圧側とが連通されている（図１１に示すＳ１）。 Next, a specific operation of the pressure regulating valve 20 during the fuel supply pump operation will be described. In the pressure regulating valve 20 configured as described above, when the engine is stopped, the piston 22 slides toward the one end side 21c, and the body hole 21b is completely closed by the piston 22 (see FIG. 4). State shown.) In this state, the high pressure side and the low pressure side are communicated with each other only through the air vent hole 22a fitted in the piston (S1 shown in FIG. 11).

この状態からエンジンが始動して、エンジンの燃料供給ポンプは、エンジン回転数の上昇に伴って吐出量が増加していくので、エンジン回転数が上昇していくと、燃料噴射ポンプの燃料ギャラリ内の圧力も上昇していき、ピストン２２は該圧力によりバネ収納室２１ｄ側へ摺動していく。そして、ピストン２２が嵌通孔２１ａとの挿入部を完全に脱するまでの間、該ピストン２２の段付部２４により形成される間隙部２１ｆが徐々に増加し、燃料ギャラリと低圧側とを連通する開口部面積は、エア抜き孔２２ａと、間隙部２１ｆとの合計となる為、全体として、緩やかに増加する（図１１に示すＳ２）。 Since the engine is started from this state and the discharge amount of the fuel supply pump of the engine increases as the engine speed increases, when the engine speed increases, the fuel gallery in the fuel injection pump The pressure of the piston 22 also rises, and the piston 22 slides toward the spring accommodating chamber 21d by the pressure. The gap 21f formed by the stepped portion 24 of the piston 22 gradually increases until the piston 22 completely removes the insertion portion with the fitting hole 21a, and the fuel gallery and the low pressure side are separated. Since the area of the opening that communicates is the sum of the air vent hole 22a and the gap 21f, the area gradually increases as a whole (S2 shown in FIG. 11).

その後更にエンジン回転数が上昇し、吐出量が増加すると、本体孔２１ｂが開口し始め、ピストン２２の摺動距離に伴ってその開口面積が大きくなる為、燃料ギャラリと低圧側とを連通する開口部面積は、エア抜き孔２２ａと、間隙部２１ｆと、本体孔２１ｂとの合計となる為、全体として急激に増加し、該本体孔２１ｂが完全に開口した状態（図５に示す状態。）で、燃料ギャラリと低圧側とを連通する開口部面積は最大値となる（図１１に示すＳ３）。 Thereafter, when the engine speed further increases and the discharge amount increases, the main body hole 21b starts to open, and the opening area increases with the sliding distance of the piston 22, so that the fuel gallery communicates with the low pressure side. Since the partial area is the sum of the air vent hole 22a, the gap portion 21f, and the main body hole 21b, the whole area is rapidly increased and the main body hole 21b is completely opened (the state shown in FIG. 5). Thus, the area of the opening that communicates the fuel gallery and the low-pressure side becomes the maximum value (S3 shown in FIG. 11).

これに対し、図１２に示した従来の調圧弁１００は、ピストン１０２が一定の摺動量に達するまで（即ち燃料ギャラリ内圧力が所定の圧力に達するまで）は、開口面積Ｓは極僅かなエア抜き孔１０２ａ分の面積のみであり、その摺動量を超えると、本体孔１０１ｂが開口し始めて、ピストン１０２の摺動量に応じて開口面積が急激に増加する。 On the other hand, the conventional pressure regulating valve 100 shown in FIG. 12 has a very small opening area S until the piston 102 reaches a certain sliding amount (that is, until the pressure in the fuel gallery reaches a predetermined pressure). The area is only the area for the extraction hole 102a. When the sliding amount is exceeded, the main body hole 101b starts to open, and the opening area increases rapidly according to the sliding amount of the piston 102.

このように、従来の調圧弁１００においては、エンジン回転数が低いときには開口面積Ｓが殆どゼロに近い状態であるので、燃料供給ポンプからの燃料圧が殆ど全て燃料ギャラリ内に蓄積され、図１０に示すように、エンジン回転数がローアイドル時の低い回転数Ｎ１であるときから燃料ギャラリ内の圧力は、ほぼ定格運転時に近い圧力Ｐ２となっている。 As described above, in the conventional pressure regulating valve 100, when the engine speed is low, the opening area S is almost zero, so almost all the fuel pressure from the fuel supply pump is accumulated in the fuel gallery. As shown in FIG. 3, the pressure in the fuel gallery is almost the pressure P2 at the time of rated operation since the engine speed is the low speed N1 at the time of low idling.

一方、本発明の調圧弁２０においては、エンジン回転数が低い時でも、間隙部２１ｆの開口によって、全体としてある程度の開口面積を確保できる為、燃料供給ポンプからの燃料圧の一部が、本体孔２１ｂと連通穴２１ｅを介して、低圧側へ逃げていくこととなり、ローアイドル時の低い回転数Ｎ１には、燃料ギャラリ内の圧力は、前記圧力Ｐ２よりもかなり低い圧力Ｐ３となっている。そして、エンジン回転数が増加していくと、それに伴って燃料ギャラリ内の圧力も増加し、定格運転時の回転数Ｎ２となると、本体孔２１ｂは全開となり、燃料ギャラリ内の圧力は、前記調圧弁１００と同様にＰ２となる。 On the other hand, in the pressure regulating valve 20 of the present invention, even when the engine speed is low, the opening of the gap portion 21f can secure a certain opening area as a whole, so that part of the fuel pressure from the fuel supply pump The pressure escapes to the low pressure side through the hole 21b and the communication hole 21e, and the pressure in the fuel gallery is considerably lower than the pressure P2 at the low rotational speed N1 during low idling. . As the engine speed increases, the pressure in the fuel gallery increases accordingly. When the engine speed reaches the rated operation speed N2, the body hole 21b is fully opened, and the pressure in the fuel gallery is adjusted as described above. Like the pressure valve 100, P2 is obtained.

ここで、燃料噴射ポンプ内でのキャビテーション・エロージョンの発生を低減する為には、燃料ギャラリ圧を高くすることが望ましく、ハンチングやエンストを防ぐ為には、燃料ギャラリ圧を低くすることが望ましいが、本発明の調圧弁２０では、燃料供給ポンプの吐出量が少ない低回転時には、燃料ギャラリの圧力を低くするとともに、燃料供給ポンプの吐出量が多い高回転時には、燃料ギャラリの圧力を高くすることができる。従って、調圧弁２０が設けられる燃料噴射ポンプにおいては、高負荷高回転時に燃料ギャラリ内の圧力を高く設定して、キャビテーション・エロージョンの発生を抑えることができるとともに、停回転時には燃料ギャラリ圧を低く設定して、ハンチングやエンストを防止することが可能となり、キャビテーション・エロージョンの低減と、ハンチングやエンストの防止との両方を実現することが可能となる。 Here, in order to reduce the occurrence of cavitation erosion in the fuel injection pump, it is desirable to increase the fuel gallery pressure, and in order to prevent hunting and engine stall, it is desirable to decrease the fuel gallery pressure. In the pressure regulating valve 20 of the present invention, the pressure of the fuel gallery is reduced at the time of low rotation with a small discharge amount of the fuel supply pump, and the pressure of the fuel gallery is increased at the time of high rotation with a large discharge amount of the fuel supply pump. Can do. Therefore, in the fuel injection pump provided with the pressure regulating valve 20, the pressure in the fuel gallery can be set high during high load and high rotation, and the occurrence of cavitation and erosion can be suppressed, and the fuel gallery pressure can be reduced during rotation. By setting it, it becomes possible to prevent hunting and engine stall, and it is possible to realize both reduction of cavitation and erosion and prevention of hunting and engine stall.

また、高圧側の燃料ギャラリ内の燃料を低圧側の燃料タンクへ流出させる為の間隙部２１ｆは、低圧側に対しては本体孔２１ｂとのみ連通し、バネ収納室２１ｄへは設けていない為、燃料ギャラリからの燃料圧が、バネ収納室２１ｄ内に侵入してピストン２２の摺動動作の妨げとなることがないようにして、低回転時に燃料ギャラリの圧力を低くできるようにしている。 Further, the gap 21f for allowing the fuel in the high-pressure side fuel gallery to flow out to the low-pressure side fuel tank communicates only with the main body hole 21b with respect to the low-pressure side, and is not provided in the spring housing chamber 21d. The fuel pressure from the fuel gallery does not enter the spring housing chamber 21d and interfere with the sliding operation of the piston 22, so that the pressure of the fuel gallery can be lowered at the time of low rotation.

次に、本発明の構成例１を、以下に説明する。本発明に係る構成例１は、実施例１と比較し、ピストン３２の形状は、従来のピストン１０２と同形状とし、調圧弁本体（ホルダー）３１の一部に嵌通孔３１ｆを加えたことにより内容を異にする。 Next, Configuration Example 1 of the present invention will be described below. In the first configuration example according to the present invention, the piston 32 has the same shape as the conventional piston 102 as compared with the first embodiment, and a fitting hole 31f is added to a part of the pressure regulating valve main body (holder) 31. Depending on the content.

［調圧弁］
即ち、図７及び図８に示すように、調圧弁３０は、嵌通孔３１ａが形成される調圧弁本体３１と、該調圧弁本体３１の嵌通孔３１ａ内に摺動自在に嵌装されるピストン３２と、該ピストン３２を摺動方向の一側に付勢するバネ３３とで構成され、且つ、該バネ３３により一端側３１ｃに付勢されて、該ピストン３２が、燃料ギャラリ内の圧力の上昇により、該バネ３３の付勢力に抗して、該ピストン３２が、バネ収納室３１ｄ側へ摺動し、本体穴３１ｂを開口する機能を有する。そして、調圧弁本体３１の嵌通孔３１ａにおいて、燃料ギャラリ内の圧力がかかっていない状態でのピストン３２先端から設定長さ摺動側に嵌通孔３１ｆを設けることにより、燃料供給ポンプの低回転時における、燃料ギャラリの圧力を低くできるようにしている。以下、調圧弁本体３１を中心に詳細を説明する。 [Pressure control valve]
That is, as shown in FIGS. 7 and 8, the pressure regulating valve 30 is slidably fitted into the pressure regulating valve main body 31 in which the fitting hole 31 a is formed and the fitting hole 31 a of the pressure regulating valve main body 31. And a spring 33 that urges the piston 32 to one side in the sliding direction, and is urged to the one end side 31c by the spring 33 so that the piston 32 is in the fuel gallery. Due to the rise in pressure, the piston 32 slides toward the spring housing chamber 31d against the urging force of the spring 33 and has a function of opening the body hole 31b. Then, in the fitting hole 31a of the pressure regulating valve main body 31, the fitting hole 31f is provided on the sliding side of the set length from the tip of the piston 32 in a state where the pressure in the fuel gallery is not applied. The pressure of the fuel gallery during rotation can be lowered. Hereinafter, the details will be described focusing on the pressure regulating valve main body 31.

［調圧弁本体］
調圧弁本体（ホルダー）３１は、従来型調圧弁本体１０１の一部に嵌通孔３１ｆを設けた構造を有する。即ち、図８において、該調圧弁本体３１を軸方向に貫く嵌通孔３１ａと、該嵌通穴と直角に嵌通する本体孔３１ｂと、該本体孔３１ｂに並列し、且つ、該調圧弁本体３１内部と外部を連通する連通孔３１ｅと、を有する従来型調圧弁本体１０１の構造において、該嵌通孔３１ａのピストン３２挿入部に、該調圧弁本体３１内部と外部を連通する嵌通孔３１ｆをピストンストローク初期部分に設けている。即ち、該嵌通孔３１ｆはピストン３２がバネ３３に抗して摺動していない状態における本体孔３１ｂとピストン３２先端との間に、本体孔３１ｂよりも小径の孔が開口して配置されている。この嵌通孔３１ｆにより、ピストン２２の摺動初期時における、燃料ギャラリ内の燃料油を徐々に低圧側へ漏出させ、該燃料ギャラリ内の圧力を急激に高くなるのを防止する構造を有する。 [Pressure adjustment valve body]
The pressure regulating valve main body (holder) 31 has a structure in which a fitting hole 31 f is provided in a part of the conventional pressure regulating valve main body 101. That is, in FIG. 8, a fitting hole 31a passing through the pressure regulating valve body 31 in the axial direction, a body hole 31b fitted perpendicularly to the fitting hole, and in parallel with the body hole 31b, the pressure regulating valve In the structure of the conventional pressure regulating valve main body 101 having a communication hole 31e that communicates the inside of the main body 31 with the outside, the fitting that communicates the inside and outside of the pressure regulating valve main body 31 with the piston 32 insertion portion of the fitting hole 31a. A hole 31f is provided in the initial part of the piston stroke. That is, the fitting hole 31f is disposed with a hole having a smaller diameter than the main body hole 31b between the main body hole 31b and the tip of the piston 32 in a state where the piston 32 does not slide against the spring 33. ing. This fitting hole 31f has a structure in which the fuel oil in the fuel gallery is gradually leaked to the low pressure side at the initial sliding of the piston 22 to prevent the pressure in the fuel gallery from rapidly increasing.

次に、調圧弁３０の動作について説明する。ピストン３２がバネ３３により一端側（ストローク始端側）に摺動している状態においては（図７に示す状態）、ピストン３２により本体孔３１ｂが閉じられているが、エア抜き孔３２ａは連通しており、燃料ギャラリ内に発生する気泡及び燃料油が徐々に低圧側へ漏出する。 Next, the operation of the pressure regulating valve 30 will be described. In a state where the piston 32 is slid to one end side (the stroke start end side) by the spring 33 (the state shown in FIG. 7), the body hole 31b is closed by the piston 32, but the air vent hole 32a is in communication. Therefore, bubbles and fuel oil generated in the fuel gallery gradually leak to the low pressure side.

この状態から、燃料ギャラリ内の圧力が上昇して、該圧力によりバネ３３の付勢力に抗してピストン３２が他端側（ストロークエンド側）へ摺動し始めると、燃料ギャラリ内の燃料油は、嵌通孔３１ａとピストン３２先端部に生じた間隙部を介して嵌通孔３１ｆを通り、低圧側へと漏出し始める。そして、ピストン３２の摺動距離が伸長するにつれて、嵌通孔３１ａとピストン３２先端部に生じる間隙部も徐々に増加し、燃料油の低圧側への漏出量を増加するが、嵌通孔３１ｆの開口断面積は一定である為、燃料油の漏出量も一定量を超えると、増加は停止する。 From this state, when the pressure in the fuel gallery rises and the piston 32 starts to slide to the other end side (stroke end side) against the biasing force of the spring 33 due to the pressure, the fuel oil in the fuel gallery Begins to leak to the low-pressure side through the fitting hole 31f via a gap formed at the tip of the fitting hole 31a and the piston 32. As the sliding distance of the piston 32 increases, the gap formed at the fitting hole 31a and the tip of the piston 32 also gradually increases, increasing the amount of fuel oil leaking to the low pressure side, but the fitting hole 31f. Since the opening cross-sectional area of the fuel oil is constant, the increase stops when the amount of fuel oil leakage exceeds a certain amount.

燃料ギャラリ内の圧力が更に上昇し、ピストン３２の一側端が嵌通孔３１ａとの挿入部を完全に脱すると、本体孔３１ｂの開口断面積が広がり始め、燃料ギャラリと低圧側との連通部面積は急激に増加する。そして、更にピストン３２は摺動し、図８に示す状態において、本体孔３１ｂは、完全に開口される。 When the pressure in the fuel gallery further increases and one end of the piston 32 completely disengages the insertion portion with the fitting hole 31a, the opening cross-sectional area of the main body hole 31b begins to expand, and the communication between the fuel gallery and the low pressure side begins. Part area increases rapidly. Further, the piston 32 slides, and in the state shown in FIG. 8, the main body hole 31b is completely opened.

以上ように、ピストン３２の摺動領域内において、実施例１と同様、燃料ギャラリ内の圧力が低圧及び高圧時の領域で、燃料ギャラリと低圧部との連通部面積の増加量を変化させる機構を設けることで、低圧領域での燃料供給圧力を、従来調圧弁と比較して、減少させ、且つ、高圧領域での燃料供給圧力を、従来調圧弁と同等に、所定の設定圧力に保持することを可能とする。その結果、燃料供給ポンプの吐出量が少ない低回転時には、燃料ギャラリ圧を低く設定して、ハンチングやエンストを防止することが可能となり、同時に、吐出量が多い高回転時には、燃料ギャラリ内の圧力を高く設定して、キャビテーション・エロージョンの発生を抑えることができる。 As described above, in the sliding region of the piston 32, as in the first embodiment, in the region where the pressure in the fuel gallery is low and high, the mechanism for changing the amount of increase in the communication portion area between the fuel gallery and the low pressure portion is changed. The fuel supply pressure in the low pressure region is reduced as compared with the conventional pressure regulating valve, and the fuel supply pressure in the high pressure region is maintained at a predetermined set pressure, equivalent to the conventional pressure regulating valve. Make it possible. As a result, the fuel gallery pressure can be set low to prevent hunting and engine stall at low revolutions when the discharge rate of the fuel supply pump is low, and at the same time, the pressure in the fuel gallery can be prevented at high revolutions with a large discharge rate. Can be set high to suppress the occurrence of cavitation erosion.

本発明の一実施例に係る、ポンプ本体の調圧弁の配設部を示す正面図。The front view which shows the arrangement | positioning part of the pressure regulation valve of the pump main body based on one Example of this invention. 同じく、調圧弁の配設部を示す平面図。Similarly, the top view which shows the arrangement | positioning part of a pressure regulation valve. 本発明の調圧弁と配設される燃料噴射ポンプを示す側面断面図。Side surface sectional drawing which shows the pressure regulation valve of this invention, and the fuel injection pump arrange | positioned. 本発明の第一実施例に係る調圧弁の、ピストンが閉じた状態を示す側面断面図。Side surface sectional drawing which shows the state which the piston closed of the pressure regulation valve which concerns on 1st Example of this invention. 本発明の第一実施例に係る調圧弁の、ピストンが開いた状態を示す側面断面図。Side surface sectional drawing which shows the state which the piston opened of the pressure regulation valve which concerns on 1st Example of this invention. 本発明の一実施例に係る、調圧弁のピストンを斜上方から見た斜視図。The perspective view which looked at the piston of the pressure regulation valve based on one Example of this invention from diagonally upward. 本発明の第一構成例に係る調圧弁の、ピストンが閉じた状態を示す側面断面図。Side surface sectional drawing which shows the state which the piston closed of the pressure regulation valve which concerns on the 1st structural example of this invention. 本発明の第一構成例に係る調圧弁の、ピストンが開いた状態を示す側面断面図。Side surface sectional drawing which shows the state which the piston of the pressure regulation valve which concerns on the 1st structural example of this invention opened. 本発明の第一構成例に係る調圧弁の、ホルダーを示した側面断面図。Side surface sectional drawing which showed the holder of the pressure regulation valve which concerns on the 1st structural example of this invention. 従来の調圧弁を用いた場合と、本発明に係る調圧弁を用いた場合の、燃料噴射ポンプ回転数の低速領域における、燃料供給圧力の差異を示す図。The figure which shows the difference of the fuel supply pressure in the low speed area | region of the fuel-injection pump rotation speed at the time of using the conventional pressure regulation valve, and the case where the pressure regulation valve which concerns on this invention is used. 調圧弁の開口面積と、ピストンの摺動量との関係を示す図。The figure which shows the relationship between the opening area of a pressure regulation valve, and the sliding amount of a piston. 従来の調圧弁に係る、ピストンが閉じた状態を示す側面断面図。Side surface sectional drawing which shows the state which the piston related to the conventional pressure regulation valve closed.

２０調圧弁
２１調圧弁本体
２２ピストン
２３バネ
２４段付部
２５調整ネジ
２１ａ嵌通孔
２１ｂ本体孔
２１ｃ嵌通孔２１ａの一端側
２１ｄバネ収納室
２１ｅ連通孔
２１ｆ間隙部 20 pressure regulating valve 21 pressure regulating valve body 22 piston 23 spring 24 stepped portion 25 adjusting screw 21a fitting hole 21b body hole 21c one end side of fitting hole 21a 21d spring accommodating chamber 21e communicating hole 21f gap

Claims

A plurality of fuel injection pumps (11) are provided inside the pump body (1), and a fuel gallery (8) through which the plurality of fuel injection pumps (11) communicate with each other is provided to constitute the fuel injection pump (11). A barrel port (7) is formed in the plunger barrel (2) in a direction perpendicular to the sliding direction of the plunger (6), and the barrel port (7) is formed in the fuel body (8) formed in the pump body (1). ), And the pump body (1) is provided with a fuel intake passage and a fuel discharge passage for communicating the fuel gallery (8) and the outside, and fuel is supplied from the fuel intake passage to the fuel gallery (8), barrel port. (7) is supplied into the pump chamber (3), and the release oil is configured to be discharged from the fuel discharge passage to the fuel tank side via the barrel port (7) and the fuel gallery (8). Fuel gallery (8) and low The pressure regulating valve (20) is interposed between the fuel tank on the side, and the pressure regulating valve (20) is formed in the pressure regulating valve main body (21) and the fitting hole (21a) formed in the pressure regulating valve main body (21). ) And a spring (23) that biases the piston (22) toward the closing side, and the piston stroke between the pressure regulating valve body (21) and the piston (22) A relief mechanism is provided in the initial portion, and the relief mechanism is provided with a stepped portion (24) in which the diameter of the fitting hole (21a) is smaller than that of the fitting hole (21a) at the end of the piston (22). The dimension (a) of the length of the stepped portion (24) in the axial direction is such that the piston (22) inserted into the fitting hole (21a) is located in the middle in the longitudinal direction of the pressure regulating valve body (21). A book that opens in a direction perpendicular to the fitting hole (21a) and communicates with the fuel gallery (8). The hole (21b) is closed and is slightly shorter than the insertion depth (b) in a state in which no pressure is received from the fuel gallery (8) side. The piston (22) and the fitting hole (21a) The fuel injection device is characterized in that a minute latching portion having a dimension (c) is formed between the piston and the position of the piston (22) .