JP2010138870A

JP2010138870A - Fuel pump and fuel supply device

Info

Publication number: JP2010138870A
Application number: JP2008318083A
Authority: JP
Inventors: Masashi Iwasaki; 真史岩崎; Akiyuki Wakabayashi; 晃行若林; Shinya Yamaguchi; 真也山口
Original assignee: Nikki Co Ltd
Current assignee: Nikki Co Ltd
Priority date: 2008-12-15
Filing date: 2008-12-15
Publication date: 2010-06-24

Abstract

【課題】プランジャ往復式の燃料ポンプについて、ロッドシールを配置することなしに燃料加圧室からカム室に液相の燃料が漏洩することを防止して良好なポンプ性能を確保できるようにする。
【解決手段】軸受３３ａ，３３ｂで軸支されたカム軸３２を有するカム室３１と、カム軸３２を軸周りに回動させる電動モータ４０と、基端側をカム室３１内に突出してカム３２ａ外周面に当接しながら先端側を燃料加圧室３６内に突出するプランジャ３５と、プランジャ３５を中心軸方向に往復摺動可能に挿通したシリンダ３４とを備え、電動モータ４０の駆動により回動するカム３２ａ外周面の変位動作でプランジャ３５が往復摺動することにより燃料加圧室３６内に導入した燃料を加圧して送出する燃料ポンプ３において、シリンダ３４がカム室３１下方に配置されてプランジャ３５の摺動方向を鉛直線に沿う上下方向となる向きとされ、カム室３１の軸受３３ａ，３３ｂ下端が燃料タンク２の満タン時液面よりも高い位置になるように配置した。
【選択図】図１A plunger reciprocating fuel pump prevents liquid phase fuel from leaking from a fuel pressurizing chamber to a cam chamber without providing a rod seal, thereby ensuring good pump performance.
A cam chamber (31) having a cam shaft (32) supported by bearings (33a, 33b), an electric motor (40) for rotating the cam shaft (32) around the shaft, and a cam with a proximal end projecting into the cam chamber (31). A plunger 35 that protrudes into the fuel pressurizing chamber 36 while abutting on the outer peripheral surface 32a and a cylinder 34 that is inserted into the plunger 35 so as to be slidable back and forth in the central axis direction. In the fuel pump 3 that pressurizes and feeds fuel introduced into the fuel pressurizing chamber 36 by the reciprocating sliding of the plunger 35 by the displacement operation of the outer peripheral surface of the moving cam 32a, the cylinder 34 is disposed below the cam chamber 31. Thus, the sliding direction of the plunger 35 is set to the vertical direction along the vertical line so that the lower ends of the bearings 33a and 33b of the cam chamber 31 are higher than the liquid level when the fuel tank 2 is full. It was placed.
[Selection] Figure 1

Description

本発明は、内燃機関の燃料供給システムに配置される燃料ポンプ及び燃料供給装置に関し、殊に、モータ等の駆動手段によりカム軸を回動させプランジャの直線往復動作に変換して、燃料を加圧・送出するプランジャ往復式の燃料ポンプ及びこれを備えた燃料供給装置に関する。 The present invention relates to a fuel pump and a fuel supply device arranged in a fuel supply system for an internal combustion engine, and in particular, a camshaft is rotated by a driving means such as a motor to convert it into a linear reciprocating motion of a plunger to add fuel. The present invention relates to a pressure reciprocating plunger reciprocating fuel pump and a fuel supply device including the same.

プランジャ往復式の燃料ポンプでは、プランジャ先端側の燃料加圧室内で加圧された燃料が、シリンダとプランジャの隙間からプランジャ基端側のカム室に漏れて液溜まりを形成することがあり、このカム室に侵入した液相燃料でカムに装着した転がり軸受やカム軸の軸受に充填されたグリース等の潤滑剤が洗い流されて、軸受の潤滑性を著しく劣化させ、ポンプ性能を損なってしまうことが知られている。 In the plunger reciprocating fuel pump, fuel pressurized in the fuel pressurizing chamber on the plunger tip side may leak from the gap between the cylinder and the plunger to the cam chamber on the plunger proximal side, forming a liquid pool. Lubricants such as grease filled in rolling bearings and camshaft bearings attached to the cam with liquid-phase fuel that has entered the cam chamber may be washed away, significantly reducing the lubricity of the bearing and impairing pump performance. It has been known.

このようなシリンダとプランジャの隙間を介した燃料漏れの問題を回避するために、ロッドシールを用いることが一般に行われているが、ロッドシールは通常、弾性樹脂材などをプランジャロッドに圧接させて外部への燃料漏れを防止するものであり、常時、プランジャロッドに摩擦による負荷が作用して駆動源におけるエネルギーの損失を生じることになり、特に、高圧の燃料ポンプにおいては高い圧接力が必要でエネルギー損出量も大きくなるばかりか構成も複雑になり、使用によりシールが損傷、摩耗するという問題もある。 In order to avoid the problem of fuel leakage through the gap between the cylinder and the plunger, a rod seal is generally used. However, the rod seal is usually formed by pressing an elastic resin material or the like against the plunger rod. This is to prevent fuel leakage to the outside, and a load due to friction acts on the plunger rod at all times, resulting in loss of energy in the drive source. Particularly, a high pressure fuel pump requires a high pressure contact force. In addition to an increase in the amount of energy loss, the structure becomes complicated, and there is a problem that the seal is damaged and worn by use.

また、例えば特開平１０−３１８１２３号公報や特開２００８−１５７２３３号公報に記載されているように、シリンダ内周面の中途位置に溝状の漏洩燃料貯留室を設けて、貯留した漏洩燃料がリターン通路を通り燃料タンクに回収されるようにした燃料ポンプが記載されているが、漏洩燃料貯留室を設けた場合でも、燃料加圧室側または漏洩燃料貯留室側とカム室側との圧力差が大きくなる高圧の燃料ポンプにおいては、圧力差によりこれらを通過してカム室まで燃料が到達することがある。この場合、漏洩燃料が気相である場合にはカム室の潤滑剤に影響を与えないのに対し、漏洩燃料が液相である場合には潤滑材を洗い流してしまうため、軸受の潤滑性を損なってポンプ性能を著しく悪化させる結果となる。
特開平１０−３１８１２３号公報特開２００８−１５７２３３号公報 Further, as described in, for example, Japanese Patent Application Laid-Open No. 10-318123 and Japanese Patent Application Laid-Open No. 2008-157233, a groove-like leaked fuel storage chamber is provided in the middle of the cylinder inner peripheral surface, and the stored leaked fuel is Although the fuel pump is described so as to be collected in the fuel tank through the return passage, the pressure between the fuel pressurizing chamber side or the leaked fuel storage chamber side and the cam chamber side even when the leaked fuel storage chamber is provided. In a high-pressure fuel pump in which the difference becomes large, fuel may pass through these to the cam chamber due to a pressure difference. In this case, when the leaked fuel is in the gas phase, the lubricant in the cam chamber is not affected, whereas when the leaked fuel is in the liquid phase, the lubricant is washed away. Resulting in a significant deterioration in pump performance.
JP-A-10-318123 JP 2008-157233 A

本発明は、上記のような問題点を解決しようとするものであり、プランジャ往復式の燃料ポンプについて、ロッドシールを使用しないことでエネルギー損失を防止するとともに燃料加圧室からカム室に液相の燃料が漏洩することを防止して良好なポンプ性能を確保できるようにすることを課題とする。 The present invention is intended to solve the above-described problems, and in a plunger reciprocating fuel pump, energy loss is prevented by not using a rod seal and a liquid phase is transferred from the fuel pressurizing chamber to the cam chamber. It is an object to prevent the fuel from leaking and to secure good pump performance.

そこで、本発明は、軸受で軸支されたカム軸を有するカム室と、前記カム室に隣接配置されて前記カム軸を軸周りに回動させる駆動手段と、基端側を前記カム室内に突出してカム外周面に当接しながら先端側を燃料加圧室内に突出するプランジャと、前記プランジャを中心軸方向所定範囲で往復摺動可能に挿通したシリンダとを備え、前記駆動手段の駆動により回動する前記カム外周面の変位動作で前記プランジャが往復摺動することにより、前記燃料加圧室内に導入した燃料を加圧して送出する燃料ポンプにおいて、前記シリンダが前記カム室の下方に配置されて前記プランジャの摺動方向を鉛直線に沿う上下方向になる向きにするとともに、前記カム室の軸受下端が燃料タンクの満タン時液面よりも高い位置になるように配置した。 Accordingly, the present invention provides a cam chamber having a cam shaft supported by a bearing, drive means arranged adjacent to the cam chamber to rotate the cam shaft around the shaft, and a base end side in the cam chamber. A plunger that protrudes into the fuel pressurizing chamber while projecting and coming into contact with the outer peripheral surface of the cam; and a cylinder that is slidably reciprocated within a predetermined range in the central axis direction. In the fuel pump that pressurizes and feeds the fuel introduced into the fuel pressurizing chamber by the reciprocating sliding of the plunger by the displacement operation of the cam outer peripheral surface that moves, the cylinder is disposed below the cam chamber. The plunger is slid in the vertical direction along the vertical line, and the lower end of the bearing in the cam chamber is positioned higher than the liquid level when the fuel tank is full.

このように、燃料ポンプをシリンダがカム室の下方でプランジャを上下に往復摺動する配置とし、カム室の軸受下端が燃料タンクの液面よりも常に高い位置になるように配置することにより、燃料加圧室から漏洩した液相の燃料がその高低差によりカム室の軸受下端まで達しにくくなる。同時に、ロッドシールを必要としなくても燃料漏れを防げるのでロッドシールによるエネルギー損失や保守が不要である。 Thus, by arranging the fuel pump so that the cylinder is reciprocally slid up and down below the cam chamber and the bearing lower end of the cam chamber is always higher than the liquid level of the fuel tank, The liquid phase fuel leaking from the fuel pressurizing chamber is difficult to reach the lower end of the bearing in the cam chamber due to the height difference. At the same time, fuel leakage can be prevented without requiring a rod seal, so energy loss and maintenance by the rod seal are unnecessary.

また、この場合にカム室にはカム室内部を外部側に連通させる気相連通孔が開口しており、この気相連通孔を介してカム室と燃料タンクの気相部分とが接続されることを特徴としたものとすれば、カム室と燃料タンク気相部分とが接続・連通することにより両空間が等圧になってカム室と漏洩燃料貯留室との圧力差が小さくなるとともに、漏洩した液相燃料が燃料タンク液面よりも高い位置まで上がりにくくなりカム室の軸受下端に一層達しにくい。 Further, in this case, the cam chamber has a gas phase communication hole for communicating the inside of the cam chamber with the outside, and the cam chamber and the gas phase portion of the fuel tank are connected via the gas phase communication hole. If the cam chamber and the fuel tank gas phase part are connected and communicated with each other, both spaces become equal pressure, and the pressure difference between the cam chamber and the leaked fuel storage chamber is reduced. The leaked liquid-phase fuel is unlikely to rise to a position higher than the liquid level of the fuel tank, making it difficult to reach the lower end of the bearing in the cam chamber.

さらに、上述した燃料ポンプにおいて、その駆動手段はモータであって、このモータはシール手段を介してカム室を構成するケーシングの取付面にモータ内部を気密状態にして取り付けられており、且つ、カム室とモータの内部とが連通路で接続されて連通していることを特徴としたものとすれば、モータ内部が気密状態でカム室と等圧になるため、駆動軸とカム軸の接続部分からカム室内の圧力が外部に漏洩しにくい。 Further, in the fuel pump described above, the driving means is a motor, and the motor is attached to the mounting surface of the casing constituting the cam chamber via the sealing means with the inside of the motor being airtight, and the cam If the chamber and the inside of the motor are connected and communicated with each other through a communication path, the motor interior is in an airtight state and is at the same pressure as the cam chamber. The pressure in the cam chamber is difficult to leak to the outside.

さらにまた、上述した燃料ポンプにおいて、そのシリンダまたはシリンダ上方のプランジャ挿通部分に、燃料加圧室から漏洩した液相の燃料を溜める所定の容積を有した漏洩燃料貯留室がプランジャ周りに形成されており、この漏洩燃料貯留室にはその内部を外部側に連通させる液相連通孔が開口しており、この液相連通孔を介して漏洩燃料貯留室と燃料タンク気相部分とが接続されることを特徴としたものとすれば、漏洩燃料貯留室に入った液相の漏洩燃料を連続的に燃料タンク側に回収することで漏洩燃料貯留室に燃料が過剰に溜まりにくくなり、それより上方のカム室まで達しにくくすることができる。 Furthermore, in the fuel pump described above, a leaked fuel storage chamber having a predetermined volume for storing liquid fuel leaked from the fuel pressurizing chamber is formed around the plunger in the cylinder or a plunger insertion portion above the cylinder. The leaky fuel storage chamber has a liquid-phase communication hole that communicates the inside with the outside, and the leaky fuel storage chamber and the fuel tank gas-phase portion are connected via the liquid-phase communication hole. In this case, the liquid-phase leaked fuel that has entered the leaky fuel storage chamber is continuously collected to the fuel tank side, making it difficult for fuel to accumulate excessively in the leaky fuel storage chamber. It can be difficult to reach the cam chamber.

この場合、その漏洩燃料貯留室が燃料タンクの満タン時液面よりも高い位置に配置されることを特徴としたものとすれば、その高低差により溜まった燃料を燃料タンク側にスムースに回収することができる。 In this case, if the leaked fuel storage chamber is arranged at a position higher than the liquid level when the fuel tank is full, the fuel accumulated due to the difference in level is smoothly recovered to the fuel tank side. can do.

加えて、上述した燃料ポンプと、燃料タンクと、燃料タンクから延設され燃料ポンプに接続された燃料供給配管とを備えている燃料供給装置において、その燃料ポンプはカム室の軸受下端が燃料タンクの満タン時液面よりも高くなる位置に配置されていることを特徴としたものとすれば、カム室への液相燃料の漏洩防止機能が確実に発揮される。 In addition, in the fuel supply apparatus including the above-described fuel pump, a fuel tank, and a fuel supply pipe extending from the fuel tank and connected to the fuel pump, the lower end of the bearing in the cam chamber has a fuel tank at the lower end of the bearing. If it is arranged at a position that is higher than the liquid level when the tank is full, the function of preventing the liquid phase fuel from leaking into the cam chamber is reliably exhibited.

また加えて、上述の気相連通孔を備えた燃料ポンプと、燃料タンクと、燃料タンクから延設され燃料ポンプに接続された燃料供給配管とを備えて、燃料ポンプをカム室の軸受下端が燃料タンクの満タン時液面よりも高くなる位置に配置した燃料供給装置において、カム室と燃料タンク気相部分とがその気相連通孔を介し導管で接続されていることを特徴としたものとすれば、カム室内部と燃料タンク気相部分とが等圧になってカム室と漏洩燃料貯留室との圧力差が確実に縮小されて燃料がカム室まで到達しにくくなる。 In addition, the fuel pump includes the above-described gas phase communication hole, a fuel tank, and a fuel supply pipe that extends from the fuel tank and is connected to the fuel pump. In the fuel supply device arranged at a position higher than the liquid level when the fuel tank is full, the cam chamber and the fuel tank gas phase part are connected by a conduit via the gas phase communication hole As a result, the cam chamber and the fuel tank gas phase become equal in pressure, and the pressure difference between the cam chamber and the leaked fuel storage chamber is reliably reduced, making it difficult for the fuel to reach the cam chamber.

更に加えて、上述の漏洩燃料貯留室を備えた燃料ポンプと、燃料タンクと、燃料タンクから延設され燃料ポンプに接続された燃料供給配管とを備え、燃料ポンプをカム室の軸受下端が燃料タンクの満タン時液面よりも高くなる位置に配置され、且つ、カム室と燃料タンク気相部分とが気相連通孔を介し導管で接続された燃料供給装置において、漏洩燃料貯留室と燃料タンクとが液相連通孔を介し燃料回収管で接続されていることを特徴としたものとすれば、漏洩した燃料を確実に循環使用しながらそれより上方に位置するカム室内に液相の漏洩燃料が一到達しにくいものとすることができる。 In addition, the fuel pump includes the above-described leaked fuel storage chamber, a fuel tank, and a fuel supply pipe extending from the fuel tank and connected to the fuel pump. In a fuel supply device in which a cam chamber and a fuel tank gas phase part are connected by a conduit via a gas phase communication hole, the leaked fuel storage chamber and the fuel are arranged at a position higher than the liquid level when the tank is full. If the tank is connected by a fuel recovery pipe via a liquid phase communication hole, the leaked fuel is reliably circulated and used while the liquid phase leaks into the cam chamber located above it. It is possible to make the fuel difficult to reach.

そしてこの燃料供給装置において、その漏出燃料貯留室が燃料タンクの満タン時液面よりも高い位置とされていることを特徴としたものとすれば、燃料タンクの液面との高低差により漏出燃料貯留室に侵入する液相燃料の量を確実に少なくするとともに燃料を燃料タンクにスムースに回収することができる。 In this fuel supply device, if the leaked fuel storage chamber is located at a position higher than the liquid level when the fuel tank is full, the leakage occurs due to the difference in level from the liquid level of the fuel tank. The amount of liquid phase fuel entering the fuel storage chamber can be reliably reduced and the fuel can be smoothly collected in the fuel tank.

プランジャが上下に往復動作するとともにカム室の軸受が燃料タンクの液面よりも常に高い位置になるものとした本発明によると、燃料加圧室からカム室に液相の燃料が漏洩することを有効に防止して良好なポンプ性能を確保できるものである。 According to the present invention in which the plunger reciprocates up and down and the bearing of the cam chamber is always positioned higher than the liquid level of the fuel tank, liquid phase fuel leaks from the fuel pressurizing chamber to the cam chamber. It can be effectively prevented to ensure good pump performance.

以下に、図面を参照しながら本発明を実施するための最良の形態について説明する。 The best mode for carrying out the present invention will be described below with reference to the drawings.

図１は、本実施の形態である燃料供給装置１の配置図を示している。この燃料供給装置１は、燃料タンク２と燃料ポンプ３と燃料供給配管６を備えて、車両用エンジン等における燃料供給システムの一部を構成するものであり、燃料タンク２に貯留したガソリン等の燃料を、燃料供給配管６を介し燃料ポンプ３の燃料加圧室３６に導入して、所定圧力に加圧し図示しないエンジンのインジェクタ等に送出するためのものである。 FIG. 1 shows a layout of a fuel supply device 1 according to the present embodiment. The fuel supply device 1 includes a fuel tank 2, a fuel pump 3, and a fuel supply pipe 6, and constitutes a part of a fuel supply system in a vehicle engine or the like, such as gasoline stored in the fuel tank 2. The fuel is introduced into the fuel pressurizing chamber 36 of the fuel pump 3 via the fuel supply pipe 6, pressurized to a predetermined pressure, and sent to an engine injector (not shown) or the like.

その燃料ポンプ３は、ポンプ本体３０とポンプ駆動手段である電動モータ４０からなり、ポンプ本体３０には、燃料供給配管６が接続し入口側と出口側に各々逆止弁を備えた燃料加圧室３５と、カム３２ａを有したカム軸３２及びこれを軸支するボールベアリング式の軸受３３ａ，３３ｂを内装してなるカム室３１と、基端側をカム室３１内に突出しながらカム３２ａ外周面に当接し先端側を燃料加圧室３６内に突出するプランジャ３５と、プランジャ３５をその中心軸方向所定範囲で摺動可能に挿通したシリンダ３４を備えている。尚、カム３２ａは偏芯した円カムであってその外周側にもボールベアリン式の軸受３３ｃが装着されており、プランジャ３５のスムースな往復動作を実現しやすい。特に、本実施の形態ではシリンダ３４におけるプランジャ３５の露出端に従来のようなロッドシールが配置されていない。 The fuel pump 3 includes a pump main body 30 and an electric motor 40 as a pump driving means. The fuel pressure is provided to the pump main body 30 by a fuel supply pipe 6 and provided with check valves on the inlet side and the outlet side, respectively. A cam chamber 31 having a chamber 35, a cam shaft 32 having a cam 32a, and ball bearing type bearings 33a and 33b for supporting the cam shaft 32, and an outer periphery of the cam 32a while projecting the base end side into the cam chamber 31. A plunger 35 abutting on the surface and projecting the tip end side into the fuel pressurizing chamber 36 and a cylinder 34 through which the plunger 35 is slidably inserted in a predetermined range in the central axis direction thereof are provided. The cam 32a is an eccentric circular cam, and a ball bearing type bearing 33c is mounted on the outer peripheral side of the cam 32a, so that the smooth reciprocation of the plunger 35 can be easily realized. In particular, in the present embodiment, a conventional rod seal is not disposed at the exposed end of the plunger 35 in the cylinder 34.

一方、電動モータ４０は、そのモータ室４１内で軸受４４ａ，４４ｂが駆動軸４３を軸支しており、その駆動軸４３の先端側が電動モータ４０に隣接配置したポンプ本体３０のカム室３１に内装したカム軸３２の一端に接続されており、電動モータ４０の駆動による駆動軸４３の回動により、カム軸３２を回動させるようになっている。尚、この電動モータ４０は、そのモータ室４１内部空間とカム室３１内部空間の両方が内外気密状態となるようにシール手段を介してポンプ本体３０の取付け部に密着・固定されている。 On the other hand, in the electric motor 40, the bearings 44 a and 44 b support the drive shaft 43 in the motor chamber 41, and the distal end side of the drive shaft 43 is placed in the cam chamber 31 of the pump body 30 disposed adjacent to the electric motor 40. The camshaft 32 is connected to one end of the camshaft 32 provided therein, and the camshaft 32 is rotated by the rotation of the drive shaft 43 driven by the electric motor 40. The electric motor 40 is closely attached and fixed to the mounting portion of the pump main body 30 via a sealing means so that both the internal space of the motor chamber 41 and the internal space of the cam chamber 31 are airtight.

以上のような燃料供給装置１の構成は、従来例とほぼ共通した周知のものであるが、以下に詳述する各構成が本実施の形態における特徴部分となっている。先ず、本実施の形態の燃料供給装置１において、燃料ポンプ３のシリンダ３４が、カム室３１の下方でプランジャ３５の摺動方向が鉛直線に沿う上下方向となる向きで配置されており、カム室３１内部でカム軸３２を軸支する軸受３３ａ，３３ｂの下端レベル（一点鎖線）が、二点鎖線で示す燃料タンク２の満タン時液面よりも高い位置となるように燃料ポンプ３が配置されている点が、本実施の形態における第１の特徴部分となっている。 The configuration of the fuel supply device 1 as described above is a well-known configuration that is almost in common with the conventional example, but each configuration described in detail below is a characteristic part of the present embodiment. First, in the fuel supply device 1 according to the present embodiment, the cylinder 34 of the fuel pump 3 is arranged below the cam chamber 31 so that the sliding direction of the plunger 35 is the vertical direction along the vertical line. The fuel pump 3 is positioned so that the lower end level (one-dot chain line) of the bearings 33a and 33b that pivotally support the camshaft 32 inside the chamber 31 is higher than the full liquid level of the fuel tank 2 indicated by the two-dot chain line. The arranged point is the first characteristic portion in the present embodiment.

このような構成としたことで、燃料加圧室３６内で加圧された燃料がシリンダ３４とプランジャ３５の隙間を通ってカム室３１側に移動しようとする場合、シリンダ３５が下向きになっている関係で重力に逆らうことになる。また、カム室３１の軸受３３ａ，３３ｂの下端側（一点鎖線＝カム室３１の底面）が、常に燃料タンク２の液面よりも高い位置となるようにしたことで、漏洩燃料がカム室３１にまで達するにはその高低差分を重力に逆らって上昇することを要するため、気相燃料よりも比重の重い液相燃料が燃料加圧室３６からシリンダ３４とプランジャ３５の隙間を介してカム室３１まで到達することを困難なものとしている。 With this configuration, when the fuel pressurized in the fuel pressurizing chamber 36 tries to move to the cam chamber 31 side through the gap between the cylinder 34 and the plunger 35, the cylinder 35 faces downward. It will be against gravity due to the relationship. Further, the lower end side of the bearings 33 a and 33 b of the cam chamber 31 (the one-dot chain line = the bottom surface of the cam chamber 31) is always higher than the liquid level of the fuel tank 2, so that the leaked fuel is in the cam chamber 31. Therefore, it is necessary to raise the difference in height against the gravity, so that the liquid phase fuel having a higher specific gravity than the gas phase fuel flows from the fuel pressurizing chamber 36 through the gap between the cylinder 34 and the plunger 35 to the cam chamber. It is difficult to reach 31.

また、燃料ポンプ３のカム室３１には、その内部（気相部）を外部側に連通させる気相連通孔３９が開口しており、この気相連通孔３９を介してカム室３１と燃料タンク２の気相部とが導管８で接続されている点が、本実施の形態の第２の特徴部分となっている。 The cam chamber 31 of the fuel pump 3 has a gas phase communication hole 39 that communicates the inside (gas phase portion) to the outside. The cam chamber 31 and the fuel are communicated with the cam chamber 31 via the gas phase communication hole 39. The point that the gas phase part of the tank 2 is connected by the conduit 8 is the second characteristic part of the present embodiment.

これにより、燃料ポンプ３のカム室３１は燃料タンク２の気相部と連通して両空間が等圧になることから、カム室３１と燃料加圧室３６との圧力差が従来例の燃料ポンプの場合よりも小さくなり、前述の高低差による作用と相俟って燃料加圧室３６から漏洩した液相燃料がカム室３１まで到達することを一層困難なものとしている。 As a result, the cam chamber 31 of the fuel pump 3 communicates with the gas phase portion of the fuel tank 2 so that both spaces have the same pressure. It becomes smaller than the case of the pump, and combined with the above-described height difference, it is more difficult for the liquid phase fuel leaking from the fuel pressurizing chamber 36 to reach the cam chamber 31.

さらに、ポンプ本体３０のカム室３１と電動モータ４０のモータ室４１とは連通路４２で接続されて連通しているとともにカム室３１とモータ室４１の両空間の外部に対する気密性が確保されている点が、本実施の形態における第３の特徴部分となっている。このように、カム軸３２を電動モータ４０の駆動軸４３と連結する部分をバイパスして接続してモータ室４１内部空間とカム室３１内部空間とが等圧の気密状態としたことにより、燃料タンク２の気相部由来の圧力が外部に漏洩することを回避可能としている。 Further, the cam chamber 31 of the pump body 30 and the motor chamber 41 of the electric motor 40 are connected and communicated with each other through a communication passage 42 and airtightness to the outside of both spaces of the cam chamber 31 and the motor chamber 41 is ensured. This is the third characteristic part in the present embodiment. As described above, the cam shaft 32 is connected by bypassing the portion connecting the drive shaft 43 of the electric motor 40 so that the internal space of the motor chamber 41 and the internal space of the cam chamber 31 are in an airtight state of equal pressure. It is possible to avoid the pressure derived from the gas phase portion of the tank 2 from leaking to the outside.

さらにまた、燃料ポンプ３におけるシリンダ３４上方のプランジャ３５を挿通している部分には、燃料加圧室３６から漏洩した液相の燃料を溜めるための所定の容積を有した漏洩燃料貯留室３７がプランジャ３５周りに形成され、その漏洩燃料貯留室３７にはその内部を外部側に連通させる液相連通孔３８が開口しており、この液相連通孔３８を介し燃料回収管７で燃料タンク２に接続している点が、本実施の形態における第４の特徴部分となっている。 Furthermore, a leaked fuel storage chamber 37 having a predetermined volume for storing liquid-phase fuel leaked from the fuel pressurizing chamber 36 is inserted into the portion of the fuel pump 3 through which the plunger 35 above the cylinder 34 is inserted. A liquid phase communication hole 38 formed around the plunger 35 and communicating with the inside of the leaked fuel storage chamber 37 to the outside is opened, and the fuel tank 2 is connected to the fuel recovery pipe 7 through the liquid phase communication hole 38. The point connected to is the fourth characteristic part in the present embodiment.

このような構成としたことで、燃料加圧室３６による圧力が強い場合において、燃料タンク２の液面との高低差による作用及びカム室３１側の圧力に抗して燃料がシリンダ３４とプランジャ３５の隙間を上昇した場合であっても、漏洩燃料貯留室３７で漏洩燃料を一端溜めるとともに燃料回収管７で燃料タンク２側に接続したことにより、溜まった燃料が逐次燃料タンク２側に回収されるため漏洩燃料がこれより上方のカム室３１に到達しにくいものとすることができ、回収した漏洩燃料はそのまま使用されるものとなる。 With such a configuration, when the pressure in the fuel pressurizing chamber 36 is strong, the fuel is opposed to the cylinder 34 and the plunger against the action due to the height difference from the liquid level of the fuel tank 2 and the pressure on the cam chamber 31 side. Even when the gap 35 is raised, the leaked fuel storage chamber 37 collects one end of the leaked fuel and connects the fuel recovery pipe 7 to the fuel tank 2 side, so that the accumulated fuel is sequentially recovered to the fuel tank 2 side. Therefore, it is possible to make it difficult for the leaked fuel to reach the cam chamber 31 above this, and the collected leaked fuel is used as it is.

尚、この漏洩燃料貯留室３７はシリンダ３４の途中に設けることもできるが、図のように燃料タンク２の満タン時液面よりも高い位置とすることにより、その高低差で漏洩燃料貯留室３７に燃料が侵入する量を少なくして漏洩燃料貯留室３７の容積を小さくすることができ、且つ、二点鎖線で示す燃料タンク２の満タン時液面との高低差による重力で、溜まった燃料を燃料タンク２にスムースに回収できるものとなる。 The leaked fuel storage chamber 37 can be provided in the middle of the cylinder 34. However, by setting the leaked fuel storage chamber 37 to a position higher than the liquid level when the fuel tank 2 is full as shown in the figure, the leaked fuel storage chamber 37 is different depending on the height. The amount of fuel entering the fuel tank 37 can be reduced and the volume of the leaked fuel storage chamber 37 can be reduced, and the fuel tank 2 can be stored by gravity due to the difference in level from the full liquid level of the fuel tank 2 indicated by a two-dot chain line. The recovered fuel can be smoothly collected in the fuel tank 2.

従って、上述した機能を発揮する燃料ポンプ３を有した燃料供給装置１を燃料供給システムに適用することにより、燃料を高圧で送出する場合であっても燃料ポンプ３のカム室３１に液相の漏洩燃料が到達することを防止することができるため、カム室３１内でカム軸３２を軸支する軸受３３ａ，３３ｂやカム３２ａに設けた軸受３３ｃの潤滑材が洗い流されてカム軸３２の回動における潤滑性が妨げられる問題を、回避することができるものとなる。 Therefore, by applying the fuel supply device 1 having the fuel pump 3 that performs the above-described function to the fuel supply system, even when the fuel is sent out at a high pressure, the liquid phase is supplied to the cam chamber 31 of the fuel pump 3. Since it is possible to prevent the leaked fuel from reaching, the lubricant in the bearings 33a and 33b that support the cam shaft 32 in the cam chamber 31 and the bearing 33c provided in the cam 32a is washed away and the rotation of the cam shaft 32 is performed. The problem that the lubricity in the movement is hindered can be avoided.

以上、述べたように、プランジャ往復式の燃料ポンプについて、本発明により、ロッドシールを使用することなしに燃料加圧室からカム室に液相の燃料が漏洩することを防止することができ、良好なポンプ性能を確保できるようになった。 As described above, for the plunger reciprocating fuel pump, according to the present invention, it is possible to prevent liquid phase fuel from leaking from the fuel pressurizing chamber to the cam chamber without using a rod seal, Good pump performance can be secured.

本発明の実施の形態を示す配置図。The layout which shows embodiment of this invention.

Explanation of symbols

１燃料供給装置、２燃料タンク、３燃料ポンプ、６燃料供給配管、７燃料回収管、８導管、３０ポンプ本体、３１カム室、３２カム軸、３２ａカム、３３ａ，３３ｂ，３３ｃ，４４ａ，４４ｂ軸受、３４シリンダ、３５プランジャ、３６燃料加圧室、３７漏洩燃料貯留室、３８液相連通孔、３９気相連通孔、４０電動モータ、４１モータ室、４２連通路、４３駆動軸
DESCRIPTION OF SYMBOLS 1 Fuel supply apparatus, 2 Fuel tank, 3 Fuel pump, 6 Fuel supply piping, 7 Fuel recovery pipe, 8 Conduit, 30 Pump main body, 31 Cam chamber, 32 Cam shaft, 32a Cam, 33a, 33b, 33c, 44a, 44b Bearing, 34 Cylinder, 35 Plunger, 36 Fuel pressurization chamber, 37 Leakage fuel storage chamber, 38 Liquid phase communication hole, 39 Gas phase communication hole, 40 Electric motor, 41 Motor chamber, 42 Communication path, 43 Drive shaft

Claims

A cam chamber having a cam shaft pivotally supported by a bearing; drive means arranged adjacent to the cam chamber to rotate the cam shaft around the shaft; The outer peripheral surface of the cam that includes a plunger that protrudes into the fuel pressurizing chamber while abutting, and a cylinder that is inserted through the plunger so as to be slidable back and forth within a predetermined range in the central axis direction, and is rotated by driving of the driving means. In the fuel pump that pressurizes and feeds the fuel introduced into the fuel pressurizing chamber by reciprocatingly sliding the plunger in the displacement operation, the cylinder is disposed below the cam chamber and the plunger slides The fuel port is arranged so that the direction is a vertical direction along a vertical line, and the lower end of the bearing of the cam chamber is positioned higher than the liquid level when the fuel tank is full. Flop.

The cam chamber has a gas phase communication hole for communicating the inside of the cam chamber to the outside, and the cam chamber and the gas phase portion of the fuel tank are connected via the gas phase communication hole. The fuel pump according to claim 1, wherein

The driving means is a motor, and the motor is attached to a mounting surface of a casing constituting the cam chamber via a sealing means with the inside of the motor being airtight, and the cam chamber and the interior of the motor The fuel pump according to claim 1, wherein the two are connected by a communication path and communicated with each other.

A leaked fuel storage chamber having a predetermined volume for storing liquid phase fuel leaking from the fuel pressurizing chamber is formed around the cylinder in the cylinder or the plunger insertion portion above the cylinder, and the leaked fuel storage chamber The chamber has a liquid phase communication hole for communicating the inside of the leaked fuel storage chamber to the outside, and the leaked fuel storage chamber and the fuel tank are connected through the liquid phase communication hole. The fuel pump according to claim 1, 2, or 3.

The fuel pump according to claim 4, wherein the leaked fuel storage chamber is disposed at a position higher than a liquid level when the fuel tank is full.

A fuel supply apparatus comprising the fuel pump according to claim 1, 2, 3, 4 or 5, the fuel tank, and a fuel supply pipe extending from the fuel tank and connected to the fuel pump. The fuel supply device according to claim 1, wherein the lower end of the bearing of the cam chamber is disposed at a position higher than a liquid level when the fuel tank is full.

A bearing for the cam chamber, comprising: a fuel pump having the gas phase communication hole according to claim 2; the fuel tank; and a fuel supply pipe extending from the fuel tank and connected to the fuel pump. In the fuel supply device in which the fuel pump is disposed at a position where the lower end is higher than the liquid level when the fuel tank is full, the cam chamber and the fuel tank gas phase portion are connected by a conduit via the gas phase communication hole. A fuel supply device characterized by being connected.

A bearing lower end of the cam chamber, comprising: a fuel pump including the leaked fuel storage chamber according to claim 4; the fuel tank; and a fuel supply pipe extending from the fuel tank and connected to the fuel pump. The fuel pump is disposed at a position where the fuel tank is higher than the liquid level when the fuel tank is full, and the cam chamber and the fuel tank gas phase portion are connected by a conduit via the gas phase communication hole In the supply apparatus, the fuel supply apparatus is characterized in that the leaked fuel storage chamber and the fuel tank are connected by a fuel recovery pipe through the liquid phase communication hole.

9. The fuel supply device according to claim 8, wherein the leaked fuel storage chamber is positioned higher than the liquid level when the fuel tank is full.