JP2007132448A - Connecting structure of circulating connector and fuel circulating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting structure of a circulating connector for easily removing the circulating connector from a fuel injection part. <P>SOLUTION: This connecting structure of the circulating connector is provided in a fuel circulating system for recirculating fuel to a fuel tank from the fuel injection part in an internal combustion engine having the fuel injection part, and is provided for joining the circulating connector to the fuel injection part; and is characterized in that the fuel injection part has a connecting part connected with the circulating connector, and the connecting part has a first groove part, and the circulating connector has an opposed part opposed to an end surface of the connecting part and a second groove part, and an elastic member is interposed between the opposed part and the end surface of the connecting part, and the circulating connector is fixed by locking the first groove part and the second groove part by a clip member in a state of pressing and holding the elastic member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a connection structure for a circulation connector and a fuel circulation system, and in particular, includes a connection structure for a circulation connector in which the circulation connector can be easily detached from a fuel injection portion, and a connection structure for such a circulation connector. Related to the fuel circulation system.

2. Description of the Related Art Conventionally, a fuel injection valve used in a common rail system of an internal combustion engine introduces a high-pressure fuel pumped from the common rail into the fuel injection valve, and then opens and closes the injection hole at the tip by the valve body. Fuel is being injected against.
Here, the high-pressure fuel that is pumped is once injected into the pressure control chamber of the fuel injection valve, and then a part thereof is released to control the valve body to open the injection hole and be injected. The surplus fuel released at this time and the fuel used as lubricating oil are recirculated to the fuel tank via the fuel circulation hose.

  In such a fuel circulation system, a fuel recirculation passage is formed by connecting the fuel injection valve and the fuel circulation hose via a circulation connector joined and fixed to the fuel injection valve. Yes. If the connection between the circulation connector and the fuel injection valve or the fuel circulation hose is insufficient, they may come off due to vibration of the internal combustion engine or the like, and the fuel may leak. Since such fuel leaks can cause engine fires, it is necessary to ensure their connection reliability.

Therefore, in order to prevent the circulation connector from being detached from the fuel injection valve, when the circulation connector is fixed to the fuel injection valve, a bracket having a large spring force is used, while the circulation connector is pushed into the fuel injection valve. There has been proposed an element coupling device with a reduced insertion load.
More specifically, as shown in FIG. 8, a pair of holding openings 443 are formed in the peripheral wall of the port member 421, and a pair of leg portions 446 of the U-shaped clip member 444 are passed through the connector member. When the 431 is pushed into the port member 421, the leg portion 446 is once expanded, and the projecting portion of the leg portion 446 is engaged with the holding groove 441 so that the required element coupling is achieved. In the coupling device 404, the clip member 441 is connected to the port member 421 so that the line connecting the centers of the arcs forming the curved surfaces of the protrusions deviates from the center of the diameter of the circumferential surface 441 A of the holding groove 441 by a predetermined length. The element coupling device 404 is attached (see Patent Document 1).
JP2003-329184A (FIG. 2)

However, the element coupling device disclosed in Patent Document 1 can easily insert the circulation connector into the fuel injection valve, but quickly removes the circulation connector from the fuel injection valve when performing maintenance or the like. There was a case that could not be done.
That is, the circulation connector is pushed into the opening of the fuel injection valve, and a certain amount of force is required to pull it out. Moreover, when removing, it is necessary to pull out quickly while expanding the clip member. Furthermore, the size of the circulation connector itself is small, and since the fuel circulation hose is connected to the circulation connector, the connector cannot be rotated, so that it is difficult to apply force. Therefore, workability when removing the circulation connector may be deteriorated.

Therefore, the inventors of the present invention have made diligent efforts, and in the connection structure of the circulation connector to the fuel injection valve, by interposing an elastic member between the connecting portion of the fuel injection valve and the facing portion of the circulation connector, The present inventors have found that the above-described problems can be solved and completed the present invention.
That is, an object of the present invention is to provide a connection structure for a circulation connector that makes it easy to remove the circulation connector from the fuel injection portion by using the repulsive force of an elastic member, and a connection structure for such a circulation connector. Is to provide a fuel circulation system.

  According to the present invention, in an internal combustion engine having a fuel injection portion, the fuel circulation system for returning fuel from the fuel injection portion to the fuel tank is provided, and the connector for circulation is joined to the fuel injection portion. A connection structure for a circulation connector, wherein the fuel injection portion includes a connection portion to which the circulation connector is connected, the connection portion has a first groove portion, and the circulation connector is connected to an end surface of the connection portion. An opposing member and a second groove, and an elastic member is interposed between the opposing portion and the end face of the connecting portion, and the elastic member is pressed and held, and the first groove and the second groove By locking the groove portion with the clip member, the circulation connector connection structure is provided, which is characterized in that the circulation connector is fixed, and the above-described problems can be solved.

  In configuring the connection structure for the circulation connector of the present invention, it is preferable that the elastic member is any one of an elastic rubber, a washer, and a leaf spring.

  Further, in configuring the connection structure for the circulation connector according to the present invention, the width of the second groove portion is increased by extending the wall surface on the opposite portion side in the cross-sectional shape of the second groove portion to the bottom portion of the second groove portion. It is preferable to have an inclined shape or an arc shape.

  Further, in configuring the connection structure for the circulation connector of the present invention, it is preferable that the thickness of the elastic member is set to a value within the range of 0.1 to 1.0 mm.

  Another aspect of the present invention is a fuel circulation system for recirculating fuel from a fuel injection unit to a fuel tank in an internal combustion engine having a fuel injection unit, wherein a circulation connector is provided to the fuel injection unit. The connection structure of the connector for circulation for joining is provided, the fuel injection portion includes a connecting portion to which the connector for circulation is connected, the connecting portion has a first groove portion, and the connector for circulation is connected to the connecting portion. A first groove portion and a second groove portion, wherein an elastic member is interposed between the opposite portion and the end surface of the connecting portion, and the elastic member is pressed and held. The fuel circulation system is characterized in that the circulation connector is fixed by locking the second groove with a clip member.

According to the connection structure and the fuel circulation system of the circulation connector of the present invention, the circulation that is press-fitted into the connection portion by interposing the elastic member between the connection portion of the fuel injection portion and the facing portion of the circulation connector. The connector can be easily removed. Therefore, work efficiency such as maintenance of the fuel circulation system can be improved.
Moreover, by interposing an elastic member at a predetermined location, the first groove portion, the second groove portion, and the clip member are pressed, and rattling of the circulation connector can be reduced.
Further, since the circulation connector is easily removed, the degree of sealing of an O-ring or the like for preventing fuel leakage can be further increased, and fuel leakage can be effectively prevented.

  Embodiments of a connection structure for a circulation connector and a fuel circulation system according to the present invention will be described below in detail. However, this embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

An embodiment according to the present invention is provided in a fuel circulation system for recirculating fuel from a fuel injection section to a fuel tank in an internal combustion engine having a fuel injection section. , Which may be simply referred to as a connector), and a fuel circulation system using a circulation connector connection structure and a circulation connector connection structure.
In such a connection structure for the circulation connector, the fuel injection portion includes a connection portion to which the circulation connector is connected, the connection portion has a first groove portion, and the circulation connector faces the end surface of the connection portion. A first groove portion and a second groove portion in a state in which an elastic member is interposed between the opposite portion and the end surface of the connecting portion and the elastic member is pressed and held. The connector for circulation is fixed by locking with a clip member.

1. Internal combustion engines Diesel engines and gasoline engines are typical as internal combustion engines, but they are equipped with a common rail system for precisely controlling the fuel injection timing, injection amount, pressure, etc., and higher pressure fuel is required. It is suitable to target diesel engines.

2. FIG. 1 shows an example of a fuel circulation system for an internal combustion engine that uses the connection structure for a circulation connector according to this embodiment.
As illustrated in FIG. 1, the fuel circulation system 80 includes a fuel tank 82, a feed pump (low pressure pump) 84 for supplying fuel in the fuel tank 82, and a fuel supply pump (high pressure pump) 83. A common rail 86 as an accumulator for accumulating the fuel pumped from the fuel supply pump 83, and a plurality of fuel injection units (injectors) for injecting the fuel pumped from the common rail 86 into the cylinders of the internal combustion engine 11).

  The feed pump 84 is a part that pumps the fuel (light oil) in the fuel tank 82 to the fuel supply pump 83, and a filter 85 is interposed between the feed pump 84 and the fuel supply pump 83. Is preferred. The feed pump 84 has a gear pump structure, but is attached to the end portion of the cam, and is directly connected to the camshaft or driven through an appropriate gear ratio through a gear drive.

The fuel pumped from the feed pump 84 through the filter 85 is further supplied to the fuel supply pump 83 via the proportional control valve 90 for adjusting the injection amount.
Further, the fuel supplied from the feed pump 84 is pressure-fed to the proportional control valve 90 and the fuel supply pump 83, and via an overflow valve (OFV) 91 provided in parallel with the proportional control valve 90. Thus, the fuel tank 82 is recirculated. A part of the fuel is pumped to a cam chamber (not shown) of the fuel supply pump 83 through an orifice (not shown) attached to the overflow valve 91 and used as fuel lubricating oil in the cam chamber. Is done.

Further, the common rail 86 is a part that temporarily stores the fuel supplied from the fuel supply pump and supplies the fuel to a high pressure state, and then pumps the fuel to each injector 11 with a uniform pressure while adjusting the injection timing. The configuration of the common rail 86 is not particularly limited, and any known one can be used.
Here, in order to adjust the pressure in the common rail 86, for example, when the pressure in the common rail 86 is reduced, a part of the fuel is returned to the fuel tank 82 via the fuel circulation hose 94.

A plurality of injectors 11 are connected to the common rail 86. Then, the fuel accumulated at a high pressure by the common rail 86 is pumped to each injector 11 and flows into a pressure control chamber (not shown) in the injector 11. The high pressure fuel flowing into the pressure control chamber urges the valve body in the direction of closing the injection hole 13, and releases a part of the high pressure fuel in the pressure control chamber to weaken the urging force of the valve body. The fuel can be injected from the injection hole 13 into the cylinder of the internal combustion engine. Thus, the fuel can be injected into the internal combustion engine via the injector 11 at an injection pressure corresponding to the rotational speed without the injection pressure being affected by fluctuations in the rotational speed of the engine.
At this time, in order to open the injection hole 13, a part of the fuel released from the pressure control chamber is supplied to the fuel via the connector 30 connected to the injector 11 and the fuel circulation hose 93 connected to the connector 30. It is returned to the tank 82.

3. Circulation Connector Connection Structure Next, the circulation connector and the connection structure thereof according to the present invention will be described with reference to FIG.
For example, an injector 11 as shown in FIG. 2 can be used as the fuel injection portion used in the connection structure of the circulation connector of the present embodiment. The injector includes a pressure control chamber 15, a valve body 19, a fuel passage 17, and an injection hole 13, and the valve body 19 is injected by high-pressure fuel that is pumped from a common rail or the like and flows into the pressure control chamber 15. The hole 13 is biased in the closing direction. When fuel is injected, a part of the fuel in the pressure control chamber 15 is released, thereby weakening the urging force of the valve body 19 and opening the injection hole 13, so that the combustion chamber of the internal combustion engine is opened. Can be injected.

In addition, the injector 11 shown in FIG. 2 includes a cylindrical connecting portion 21 to which a connector 30 is joined at an end position opposite to the injection hole 13. In addition, the connector 30 includes a head 33 having a facing portion 33 a that faces the end surface 21 a of the connecting portion 21 of the injector 11, and an insertion portion 31 that is inserted into the connecting portion 21 of the injector 11. Then, the connecting portion 21 of the injector 11 and the insertion portion 31 of the connector 30 are coaxially connected, and a part of the fuel discharged to open the injection hole 13 at the time of injection or the fuel used as lubricating oil is the connector. It flows into the fuel circulation hose 93 through 30 and is returned to the fuel tank.
More specifically, the connecting portion 21 of the injector 11 has a first groove portion 23, the insertion portion 31 of the connector 30 has a second groove portion 32, and the insertion portion 31 of the connector 30 is connected to the connecting portion of the injector 11. 21, and the first groove portion 23 and the second groove portion 32 are both pressed by the clip member 27 at the same time, thereby being fixed so as not to be easily removed.
Moreover, the insertion part 31 inserted in the connection part 21 of the injector 11 in the connector 30 is provided with an O-ring 37 to seal between the inner peripheral surface of the connection part 21 of the injector 11 and the insertion part 31. Prevents fuel from leaking outside.

Here, as shown in FIG. 3, the connection structure for the circulation connector according to the present invention includes an elastic member 42 interposed between the facing portion 33 a of the connector 30 and the end surface 21 a of the connecting portion 21 of the injector 11. The connector 30 is fixed by locking the first groove portion 23 and the second groove portion 32 with a clip member 27 in a state where the elastic member 42 is pressed and held. That is, when the connector 30 is fixed while the elastic member 42 is pressed and held, when the connector 30 is removed, as shown in FIGS. Since the second groove portion (not shown) of the connector 30 is released from the clip member 27 and the connector 30 is pushed upward by the elastic force of the elastic member 42, the removal becomes easy. Therefore, since the force required when pulling out can be reduced, work efficiency at the time of work such as maintenance can be improved.
4A is a view of the connection structure of the circulation connector as viewed from above, and FIG. 4B is a side view of the connection structure of the circulation connector of FIG. 4A as viewed from the direction of the arrow. FIG.

  In addition, since the connector can be easily detached from the injector, conversely, since the crimping force when the connector is pushed into the connecting portion of the injector can be increased, the sealing force by the O-ring or the like is improved, It is possible to effectively prevent fuel leakage.

  Further, by interposing an elastic member between the connector and the injector and holding it, an elastic force that pushes the connector 30 upward by the elastic member 42 acts in the state where the connector 30 is joined as shown in FIG. Therefore, the second groove 32 of the connector 30 and the first groove 23 of the injector 11 are pressed against the clip member 27, respectively. As a result, the connector 30 is fixed by the clip member 27 and the elastic member 42, and rattling can be eliminated. Therefore, it is possible to effectively prevent wear and damage of the connector and the connecting portion of the injector, and the O-ring for preventing fuel leakage.

  Further, as an example of an elastic member interposed between the facing portion 33a of the connector 30 and the end surface 21a of the connecting portion 21 of the injector 11, an elastic rubber 42a, a washer 42b, and a leaf spring 42c as shown in FIG. 6 are used. be able to. Such an elastic member is a preferable aspect because the thickness can be relatively reduced, and the connection structure of the circulation connector is not increased in size.

Further, as shown in FIGS. 7A to 7B, the wall surface located in the insertion direction of the insertion portion 31 in the cross-sectional shape of the second groove portion 32 of the connector 30 is extended to the bottom portion 32 c of the second groove portion 32. It is also preferable to use an inclined wall surface 32a or an arcuate wall surface 32b so that the width of the two groove portions 32 is increased.
This is because the clip member 27 is easily caught by the second groove 32, so that even if a force is applied in the direction of pushing out the connector by the elastic force of the elastic member, the connector cannot be removed unless the clip member is removed. It is because it can be made.

The thickness of the elastic member interposed between the connector and the injector is preferably set to a value within the range of 0.1 to 1.0 mm.
This is because the elastic force may not be ensured when the thickness of the elastic member is less than 0.1 mm. On the other hand, if the thickness of the elastic member exceeds 1.0 mm, the size (height) of the connector connection portion may increase.
Therefore, the thickness of the elastic member interposed between the connector and the injector is more preferably set to a value within the range of 0.1 to 0.8 mm, and the value within the range of 0.1 to 0.6 mm. More preferably.

  As described above, the elastic member is interposed between the circulation connector and the injector, and the elastic member is engaged with the clip member while being pressed and held, thereby utilizing the elastic force of the elastic member. The removal of the circulation connector can be facilitated.

It is a figure which shows the structural example of the fuel circulation system which can apply this invention. It is a figure provided in order to demonstrate the connection structure of the connector for circulation of this invention. It is a figure which shows the structural example of the connection structure of the connector for circulation of this invention. It is a figure provided in order to demonstrate the effect | action at the time of removing the connector for circulation. It is a figure provided in order to explain the state where shakiness of the connector for circulation is reduced. It is a figure which shows the example of the elastic member which can be used for the connection structure of the connector for circulation of this invention. It is a figure which shows the state which made a part of wall surface of the groove part of the connector for circulation the inclined form. It is a figure which shows the structure of the conventional connector for circulation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11: Injector, 13: Injection hole, 15: Pressure control chamber, 17: Fuel passage, 19: Valve body, 21: Connection part, 21a: End surface, 23: 1st groove part, 27: Clip member, 30: For circulation Connector, 31: Insertion section, 32: Second groove section, 32a: Inclined wall surface, 32b: Arc-shaped wall surface, 33: Head, 33a: Opposing section, 37: O-ring, 42: Elastic member, 80: Fuel circulation system, 82: Fuel tank, 83: Fuel supply pump, 84: Feed pump, 86: Common rail, 88: Booster, 93/94: Fuel circulation hose

Claims (5)

An internal combustion engine having a fuel injection unit is provided in a fuel circulation system for returning fuel from the fuel injection unit to a fuel tank, and a circulation connector for joining a circulation connector to the fuel injection unit. A connection structure,
The fuel injection part includes a connection part to which the circulation connector is connected, and the connection part has a first groove part,
The circulation connector includes a facing portion facing the end surface of the connecting portion, and a second groove portion,
An elastic member is interposed between the facing portion and the end surface of the connecting portion, and the elastic member is pressed and held, and the first groove portion and the second groove portion are locked by a clip member, thereby The connection structure for a circulation connector according to claim 1, wherein the circulation connector is fixed.   The connection structure for a circulation connector according to claim 1, wherein the elastic member is one of elastic rubber, a washer, and a leaf spring.   The wall surface on the facing portion side in the cross-sectional shape of the second groove portion is inclined or arcuate so that the width of the second groove portion increases toward the bottom of the second groove portion. Item 3. A connection structure for a circulation connector according to item 1 or 2.   The connection structure for a circulation connector according to any one of claims 1 to 3, wherein a thickness of the elastic member is set to a value within a range of 0.1 to 1.0 mm. A fuel circulation system for recirculating fuel from the fuel injection section to a fuel tank in an internal combustion engine having a fuel injection section,
A connection structure for a circulation connector for joining the circulation connector to the fuel injection part,
The fuel injection part includes a connection part to which the circulation connector is connected, and the connection part has a first groove part,
The circulation connector includes a facing portion facing the end surface of the connecting portion, and a second groove portion,
An elastic member is interposed between the facing portion and the end surface of the connecting portion, and the elastic member is pressed and held, and the first groove portion and the second groove portion are locked by a clip member, thereby A fuel circulation system, wherein a circulation connector is fixed.

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