JP2011163154A - Connector for fuel piping - Google Patents

Abstract

An object of the present invention is to eliminate the need to mount a pulsation damper on a fuel injection rail, and to add an inexpensive pulsation damper function having a high effect of reducing durability and pressure fluctuation to a pipe joint.
A cylinder portion 20 is provided integrally with a housing 18, and a piston 32 having a seal member 34 slidably contacting the inner peripheral surface of the cylinder portion 20 on the outer peripheral portion is slidably received. The fuel chamber 38 communicating with the air chamber 24 and the air chamber 36 containing air are partitioned liquid-tightly.
[Selection] Figure 3

Description

  The present invention relates to a connector as a pipe joint used in a fuel pipe of an automobile or a motorcycle, and more particularly to a connector having a pulsation damper mechanism that suppresses fuel pulsation.

  In the fuel supply system of an automobile, the fuel pulsation phenomenon appears prominently every time the injector valve opens and closes. There is a problem that the pressure fluctuation generated by the pulsation of the fuel affects a predetermined fuel injection according to the engine speed. There is also a problem that vibration is transmitted as noise to the vehicle body via the fuel pipe. For this reason, it has been conventionally performed to mount a pulsation damper on a fuel injection rail and suppress pulsation with the pulsation damper.

  As this type of pulsation damper, a diaphragm type housing in which a diaphragm and a spring for energizing the diaphragm are accommodated in a main body case (for example, Patent Document 1). In addition, there is also a type in which a piston is urged by a coil spring and the pulsation is attenuated by moving the piston against the elastic force of the coil spring (Patent Document 2).

  On the other hand, a connector in which a bellows that absorbs pulsation is accommodated inside a joint of a fuel pipe has been proposed (Patent Documents 3 and 4).

  In this connector, as a means for absorbing pulsation, a bellows formed from resin or rubber is used. The bellows is formed with a hermetically sealed air chamber so that pressure fluctuations due to pulsation are absorbed by expansion and contraction of the bellows.

JP 2001-207932 A JP 2003-003926 A JP 2004-183812 A JP 2005-344547 A

  However, the conventional diaphragm pulsation damper is an expensive part, and it is difficult to ensure durability. Furthermore, when mounting on a fuel injection rail, a sufficient mounting space is secured around the engine. There was a case where it was a restriction on installation.

  In this respect, in the damper of Patent Document 2, since the case for accommodating the piston is formed integrally with the resin fuel delivery pipe, the workability of assembly and attachment is improved, but the structure of the delivery pipe is limited. It has been done.

  Further, in the case of using the bellows as a pulsation absorber as in the connectors described in Patent Documents 3 and 4, there is an advantage that the bellows can be molded with an inexpensive resin such as a polyamide resin, but the bellows that repeatedly expands and contracts There was a problem with durability.

  Therefore, in view of the problems of the prior art, an object of the present invention is to eliminate the need to mount a pulsation damper on a fuel injection rail by incorporating a piston that partitions an air chamber and a fuel chamber into a connector that connects a fuel pipe. In addition, it is an object of the present invention to provide a connector having an inexpensive pulsation damper function that is highly effective in suppressing pressure fluctuations.

  In order to achieve the above object, the present invention provides a connector used for pipe connection in a fuel pipe for supplying fuel to a fuel injection device, wherein a male joint to which a fuel tube is connected and a counterpart fuel pipe are connected. A piston having a female joint portion having a fuel passage formed therein, a cylinder portion formed integrally with the housing, and a seal member slidably contacting the inner peripheral surface of the cylinder portion on the outer peripheral portion The piston is slidably accommodated in the cylinder portion, and the fuel chamber communicating with the fuel passage and the air chamber containing air are liquid-tightly partitioned by the piston. To do.

  Further, the present invention is a connector used for pipe connection in a fuel pipe for supplying fuel to a fuel injection device, and has a male joint part to which a fuel tube is connected and a female joint part to which a counterpart fuel pipe is connected. A housing having a fuel passage formed therein, a cylinder portion formed integrally with the housing, a hollow piston movable in the cylinder portion, and an inner peripheral surface of the cylinder portion, And a piston guide member having a second seal member slidably in contact with the inner peripheral surface of the piston. The piston guide member communicates with the fuel passage. The fuel chamber is formed, and the fuel chamber and the air chamber sealed with air are liquid-tightly partitioned by the piston fitted on the piston guide member. It is.

  According to the present invention, it is not necessary to mount a pulsation damper on the fuel injection rail, and an inexpensive pulsation damper function having a high effect of suppressing pressure fluctuation can be added to the connector.

It is a side view which shows the connector for fuel piping by this invention. It is II-II longitudinal cross-sectional view of the connector for fuel piping. It is sectional drawing which shows the principal part of 1st Embodiment of the connector for fuel piping by this invention. Explanatory drawing which shows the example which used the connector for fuel piping with the fuel piping of the engine of a motor vehicle. Explanatory drawing which shows the example which used the connector for fuel piping with the fuel piping of the engine of a two-wheeled vehicle. It is sectional drawing which shows the principal part of 2nd Embodiment of the connector for fuel piping by this invention. It is sectional drawing which shows the principal part of 3rd Embodiment of the connector for fuel piping by this invention. It is sectional drawing which shows the principal part of 4th Embodiment of the connector for fuel piping by this invention. It is sectional drawing which shows the other modification of 4th Embodiment of the connector for fuel piping by this invention. It is sectional drawing which shows the principal part of 5th Embodiment of the connector for fuel piping by this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a fuel pipe connector according to the present invention will be described with reference to the accompanying drawings.
First embodiment
1 and 2 show a fuel pipe connector according to a first embodiment of the present invention. In FIG. 1, reference numeral 10 indicates a fuel pipe connector. Reference numeral 12 indicates a resin fuel tube. The fuel tube 12 constitutes a fuel pipe that supplies fuel by a pump (not shown). Reference numeral 14 indicates a resin pipe or metal fuel pipe connected to the fuel injection rail. In this embodiment, the fuel pipe connector 10 is configured as a quick connector type connector that can be connected only by inserting the fuel pipe 14 and then pushing the retainer 16 into the locked state.

The fuel pipe connector 10 includes a housing 18 constituting a joint main body and a cylinder portion 20 having a pulsation suppressing function.
In this embodiment, the housing 18 includes a male joint portion 21 and a female joint portion 22. The male joint portion 21 is a known male joint portion that can be connected by press-fitting the fuel tube 12. The fuel tube 12 is a tube having an inner diameter of, for example, 1.5 mm to 3.5 mm. In this embodiment, the fuel tube 12 is a thin resin tube having an inner diameter of 2.5 mm.

  As shown in FIG. 2, the female joint portion 22 is a known quick connector type female joint that restrains a spool portion 19 formed at the end of the fuel pipe 14 by the retainer 16 by pushing the retainer 16 from the side. . There are various quick connectors to which the present invention can be applied. For example, a quick connector of a type that is connected by inserting the fuel pipe 14 with the retainer attached to the female joint portion. Applicable.

Next, FIG. 3 shows a cross section of the fuel pipe connector 10.
Inside the housing 18, a fuel passage 23 through which fuel flows is formed in the male joint portion 21, and a fuel passage 24 is formed in the female joint portion 22. The axial centers of the fuel passage 23 and the fuel passage 24 are orthogonal to each other.

  The female joint portion 22 includes a small cylindrical portion 25 and a large cylindrical portion 26 having both an inner diameter and an outer diameter that extend through the step portion 25a. Among these, the small cylindrical portion 25 is provided with a cylinder portion 20. Since the end portion of the counterpart fuel pipe 14 is inserted into the large cylindrical portion 26, the seal member 27 is disposed using the step portion 25a.

  The cylinder part 20 includes a cylindrical cylinder 30, a cylinder lid 31, and a piston 32. The cylinder 30 is formed of resin as a material integrally with the small cylindrical portion 25 of the housing 18. In this embodiment, the cylinder 30 is arranged coaxially with the axial center of the male joint portion 21, and the entire cylinder 30 is positioned closer to the small cylindrical portion 25 than the end face of the stepped portion 25. The cylinder lid 31 is formed as a separate part, and is fixed to the cylinder 30 by welding, thereby sealing the cylinder portion 20. In addition, you may make it fasten with a screw | thread.

  The piston 32 is accommodated in the cylinder 30 so as to be movable in the axial direction of the cylinder portion 20. A groove 33 is formed in the outer circumferential portion of the piston 32 in the circumferential direction, and an O-ring 34 is fitted in the groove 33 as a seal member.

  Inside the cylinder portion 20, the air chamber 36 and the fuel chamber 38 are liquid-tightly partitioned by the piston 32 with the O-ring 34 attached. In this embodiment, the air chamber 36 is filled with air at atmospheric pressure when the piston 32 is in the neutral position shown in FIG. In a connector to which a thin fuel tube 12 having an inner diameter of 1.5 mm to 3.5 mm is connected as in this embodiment, the volume of the air chamber 36 is caused by fuel pulsation if the volume is about 0.1 to 5 ml. It is sufficient to reduce the pressure.

  The fuel chamber 38 communicates with the fuel passage 24 inside the small cylindrical portion 25 through an opening 39 formed in the small cylindrical portion 25 of the housing 18. The opening 39 is a small-diameter opening that is narrower than the cross-sectional area of the fuel chamber 38.

  As shown in FIG. 3, the O-ring 34 attached to the outer peripheral portion of the piston 32 is pressed against the inner peripheral surface of the cylinder 30 and crushed. When the piston 32 moves, the O-ring 34 prevents the fuel from entering the air chamber 36 from the fuel chamber 38 while sliding on the inner peripheral surface of the cylinder 30. Moreover, since the speed at which the piston 32 is pushed increases as the fuel pressure increases, the sliding resistance of the O-ring 34 increases. Accordingly, the O-ring 34 gives the piston 32 a sliding resistance corresponding to the pressure fluctuation of the fuel.

  The fuel pipe connector according to the present embodiment is configured as described above. Next, the operation and effect thereof will be described.

FIG. 4 is a view showing an example in which the fuel pipe connector according to the present embodiment is used for a fuel pipe for supplying fuel to an automobile engine.
In FIG. 4, reference numeral 60 is an engine cylinder, 61 is a piston, 62 is an intake pipe, 63 is an exhaust pipe, 64 is an intake valve, 65 is an exhaust valve, 66 is an air flow meter, and 67 is an air cleaner. .

  An injector 72 is attached to the fuel injection rail 70, and the injector 72 is connected to an intake pipe 62 as shown in FIG. The fuel pipe connector 10 of the present embodiment connects a fuel tube 12 extending from a fuel tank (not shown) to an engine to a fuel injection rail 70. In this case, the fuel tube 12 is press-fitted into the male joint portion 21, and the fuel pipe 14 attached to the fuel injection rail 70 is inserted into the female joint portion 22 and locked by the retainer 16.

  1, 3, and 4, when the fuel is injected from the injector 72 of the fuel injection rail 70, the fuel pressure decreases, and when the injection ends and the valve of the injector 72 is closed, the fuel pressure increases. Since pressurized fuel is always sent from the fuel pump, the pressure fluctuation wave reflected by the injector 72 and the pressure wave from the fuel pump collide, and this repetition causes pulsation. .

  According to the fuel pipe connector of the present embodiment, the fuel tube 12 and the fuel pipe 14 are simply connected to the fuel injection rail 70 via the connector, and the cylinder portion 20 incorporating the piston 36 is used as follows. Pulsation pressure fluctuations can be absorbed.

  First, when the injection is finished and the valve of the injector 72 is closed and the fuel pressure is increased, the pressure in the fuel chamber 38 is increased and the piston 32 is moved in the direction of pushing into the air chamber 36. At this time, the air in the air chamber 36 is compressed and the pressure increases, and the piston 32 moves toward the air chamber 36 against the pressure of the air in the air chamber 36 and can absorb the increase in fuel pressure.

  On the contrary, when the valve of the injector 72 is opened at the injection timing, the fuel pressure rapidly decreases. At this time, since the pressure of the fuel chamber 38 is lowered, the piston 32 is pushed back to the fuel chamber 38 by the pressure of the air in the air chamber 36 that has been compressed so far, so that the fuel pressure drop can be absorbed. .

  When the piston 32 receives the pressure fluctuation, a sliding resistance is generated between the O-ring 34 and the inner peripheral surface of the cylinder 30. Since the pressure fluctuation at the initial stage of the pulsation is small, this pressure fluctuation is absorbed by the sliding resistance between the O-ring 34 and the inner peripheral surface of the cylinder 30. It can be absorbed by the air in the air chamber 36.

  In this way, the pulsation is effectively spread over a wide range by the sliding resistance of the O-ring 34 and the air in the air chamber 36 while the piston 32 repeats the movement following the fluctuation of the fuel pressure caused by the pulsation. Can be reduced.

  Further, unlike the conventional mechanism in which fluctuations in fuel pressure are absorbed by an elastic absorber such as a diaphragm, bellows, or spring, the air sealed in the air chamber 36 is compressed and expanded by the piston 32. Since a damper mechanism having a novel structure that has not been absorbed so far is employed, it can be manufactured at a lower cost than a damper mechanism using a diaphragm or bellows.

In order to be able to cope with a wide range of fuel pressure fluctuations, the air pressure in the air chamber 36 is made to correspond to the range of fuel pressure fluctuations, and air with a pressure higher than atmospheric pressure (preferably Air having a pressure in the range of 0.1 to 10 kgf / cm ² may be enclosed. For example, when the pressure fluctuation of the fuel is 3-5 kg / cm ^2, air pressure is 5 kg / cm ² at maximum.

Next, the structural advantage of the connector integrated with the cylinder portion 20 will be described.
According to the fuel pipe connector of the present embodiment, the cylinder portion 20 that accommodates the piston 32 is provided in the housing 18 in which the male joint portion 21 and the female joint portion 22 which are quick connectors widely used for fuel piping are integrated. Thus, a function of suppressing pressure fluctuation can be added to the quick connector itself. For this reason, it is not necessary to mount an expensive pulsation damper on the fuel injection rail as in the prior art. Therefore, it is not necessary to secure a space for mounting the pulsation damper as in the prior art, and a function for reducing pressure fluctuation caused by pulsation can be easily added without being restricted by the piping layout. .

  Further, since the cylinder 30 is integrally formed in the housing 18, the piston 32 is housed, and the cylinder lid 31 is simply welded or fixed with screws, it can be applied to general quick connectors in general. However, since the piston 32 itself is inexpensive, the cost can be greatly reduced.

  And in providing the cylinder part 20, it becomes the structure which formed the cylinder 30 integrally in the side part of the small cylindrical part 25 of the female coupling part 22, and arrange | positioned coaxially with the male coupling part 21 like this embodiment. Therefore, the projection of the cylinder part 20 in the radial direction of the male joint part 21 can be suppressed, and a coherent and compact structure can be achieved. Moreover, by adopting an integral structure with the small cylindrical portion 25, the cylinder portion 20 itself is composed of a male joint portion 21 as a press-fit connection portion required as a fuel pipe connector and a female joint portion 22 as a quick connector. It does not affect the function at all, and a simple one-touch connection operability as a quick connector and a pressure fluctuation suppressing action are compatible. Even if the pressure fluctuation suppressing function of the cylinder portion 20 is impaired, the entire connector can be removed, and the maintainability is excellent.

In FIG. 3, the inner diameter of the male joint portion 21 is D1, the inner diameter of the opening 39 communicating the fuel passage 24 and the fuel chamber 38 is D2, the inner diameter of the cylinder 30 is D3, and the inner diameter of the large cylindrical portion 26 of the female joint portion 22. Is D4 and the inner diameter of the small cylindrical portion 25 is D5,
D1 <D2 <D5 <D4 <D3
It is preferable that
By making the inner diameter D2 of the opening 39 for communicating the fuel passage 24 and the fuel chamber 38 larger than the inner diameter D1 of the male joint portion 21, for example, a thin fuel tube 12 having an inner diameter of 2.5 mm is connected. The fuel fed from the small-diameter male joint portion 21 can be smoothly guided to the fuel chamber 38 and the pressure fluctuation can be transmitted to the piston 32.

  Further, by making the inner diameter D2 of the opening 39 smaller than the inner diameter D5 of the small cylindrical portion 25, the opening 39 functions as an orifice that relieves sudden pressure fluctuations due to pulsation, and prevents sudden movement of the piston 32. This can protect the O-ring 34 from wear.

  By making the inner diameter D3 of the cylinder 30 larger than D4 of the large cylindrical portion 26 of the female joint portion 22, the cylinder 30 is relatively shortened while securing the volume of the cylinder 30, and a compact structure with suppressed protrusion is obtained. be able to. Further, by making the cylinder lid 31 coaxial with the male joint portion 21 having the inner diameter D1, a structure in which the cylinder 30 and the cylinder lid 31 are prevented from protruding in the radial direction can be achieved.

  The above is an example in which a fuel pipe connector is applied to a fuel pipe of an automobile. FIG. 5 shows an example in which the fuel pipe connector of the present invention is applied to a fuel pipe of a motorcycle.

  FIG. 5 is a plan view showing an example of the layout of fuel piping in the motorcycle. In FIG. 5, reference numeral 76 indicates an engine, 77 indicates an intake pipe, 78 indicates an exhaust pipe, 80 indicates an injector, 82 indicates a fuel tank, and 83 indicates a fuel pump. The fuel tube 12 extending from the fuel pump 83 is routed as shown in FIG. 5, and the fuel pipe connector 10 connects the injector 80 and the fuel tube 12 via the fuel injection rail 84. Thus, the fuel pipe connector 10 can also be used for the fuel pipe of a motorcycle, and can effectively reduce fuel pulsation.

Second embodiment
Next, a fuel pipe connector according to a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the second embodiment, a coil spring 40 is housed in the air chamber 36 of the cylinder portion 20 as a biasing member that biases the piston 32 toward the fuel chamber 38. The main function of the coil spring 40 is to regulate the amount of movement of the piston 32 while adjusting the fuel pressure when the piston 32 moves by biasing the piston 32 toward the fuel chamber 38.

  According to the second embodiment described above, as in the first embodiment, the air sealed in the air chamber 36 is compressed and expanded by the piston 32 to absorb fuel pressure fluctuations. In addition, since the wear of the O-ring 34 can be reduced by suppressing the amount of movement of the piston 32 in the axial direction of the cylinder 30 by the elastic force of the coil spring 40, fuel can be stored in the air chamber 36 over a long period of time. Invasion can be prevented, and the durability of the damper mechanism can be greatly improved.

Third embodiment
Next, a fuel pipe connector according to a third embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the third embodiment, a through hole 42 is formed in the cylinder lid 31 fixed to the end of the cylinder 30, and the air chamber 36 is open to the atmosphere. A coil spring 43 is accommodated in the air chamber 36 as an urging member for absorbing fuel pressure fluctuation and attenuating pulsation.

  According to the third embodiment described above, unlike the first and second embodiments, the air chamber 36 is open to the atmosphere, so the air chamber 36 itself has a function of absorbing fuel pressure fluctuations. Although the coil spring 43 expands and contracts by receiving the movement of the piston 32, the pressure fluctuation can be absorbed. Even if fuel enters the air chamber 36, the function as a damper mechanism does not change, and there is an advantage that a durable damper mechanism is obtained.

Fourth embodiment
FIG. 8 shows a fuel pipe connector according to a fourth embodiment of the present invention. The same components as those in the first embodiment in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the fifth embodiment, the arrangement position of the cylinder portion 20 is different from that of the first embodiment. As shown in FIG. 8, the cylinder portion 20 and the male joint portion 21 are coaxial with the female joint portion 22. It is constructed integrally. According to such a structure, it can be set as the compact structure in consideration of suppressing the protrusion of the cylinder part 20 to the axial direction of the male coupling part 21. FIG.

Next, FIG. 9 shows another modification of the fuel pipe connector.
In the first to third embodiments, the fuel passage 24 in the female joint portion 22 is perpendicular to the fuel passage 23 in the male joint portion 21, and the relationship between the male joint portion 21 and the female joint portion 22 is the same. In contrast to the L-shaped embodiment, this modification is a straight-shaped embodiment in which the male joint portion 21 and the female joint portion 22 are coaxial, and the structure of the present invention is all A straight connector is also applicable.

  In FIG. 9, when L1 is the width in the joint axial direction and L2 is the width of the cylinder 30, there is a relationship of L1> L2. Thereby, since the cylinder 30 is arrange | positioned in the width | variety L1 of a joint axial direction, protrusion of a joint axial direction can be suppressed.

  As described above, as shown in FIGS. 8 and 9, the configuration of the housing 18 of the fuel pipe connector can be appropriately changed in the positional relationship between the male joint portion 21 and the female joint portion 21 and the cylinder portion 20. It is possible to flexibly deal with any type of engine.

Fifth embodiment
FIG. 10 shows a fuel pipe connector according to a fifth embodiment of the present invention. The same components as those in the first embodiment in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

The fourth embodiment is an embodiment in which the structure of the piston accommodated in the cylinder portion 20 is different from the first to third embodiments.
In FIG. 10, reference numeral 44 indicates a cylindrical hollow piston whose one end is open. The hollow piston 44 is movably fitted to the cylinder 30. A piston guide member 45 is fitted into the inner diameter portion of the hollow piston 44. The piston guide member 45 is fixed to the inner peripheral surface of the cylinder 30 and is integrally formed from a large diameter portion 46a fitted to the inner peripheral surface of the cylinder 30 and a small diameter portion 46b to which the hollow piston 44 is fitted. ing.

In the fourth embodiment, the fuel chamber 47 is formed inside the piston guide member 45 and communicates with the fuel passage 24 through the opening 39. The air chamber 48 in which air is sealed is formed between the cylinder lid 31 and the end face of the hollow piston 44. The air chamber 48 and the fuel chamber 47 are hollow by providing the following sealing members. The piston 44 is liquid-tightly partitioned. The pressure of the air sealed in the air chamber 48 is atmospheric pressure or air having a pressure of 10 kg / cm ^{2 at} the maximum.

  A groove 49 is formed in the outer peripheral portion of the large-diameter portion 46 a of the piston guide member 45 in the circumferential direction, and an O-ring 50 as a first seal member is fitted in the groove 49. An O-ring 52 as a second seal member is fitted to the outer peripheral portion of the small diameter portion 46 b through a groove 51. The O-ring 50 is in contact with the inner peripheral surface of the cylinder 30, and the O-ring 52 is slidably pressed against the inner peripheral surface of the hollow piston 44 in a crushed state. A tapered surface 53 is formed on the small diameter side of the groove 51 in which the O-ring 52 is fitted. The end edge portion 54 of the hollow piston 44 is formed in a tapered shape following the tapered surface 53. As a result, the space for providing the O-ring 50 can be secured, the stroke of the hollow piston 44 can be set from the immediate vicinity of the O-ring 50, and the narrow space inside the cylinder portion 20 can be effectively utilized. .

  According to the fourth embodiment described above, as in the first embodiment, the quick connector is provided by providing the cylinder portion 20 that accommodates the hollow piston 44 integrally with the housing 18 of the quick connector that is widely used for fuel piping. Since a function of suppressing pulsation is added to the fuel injection rail itself, it is not necessary to mount an expensive pulsation damper on the fuel injection rail as in the prior art, and it can be applied to a quick connector for general use.

  And, unlike the conventional mechanism in which the fluctuation of the fuel pressure is absorbed by an elastic absorber such as a diaphragm, bellows, or spring, the air sealed in the air chamber 48 is compressed by the hollow piston 44. Since a damper mechanism that has not been absorbed so far by absorbing it is employed, there is an advantage that it can be manufactured at a lower cost than a damper mechanism that uses a diaphragm or bellows.

  In addition, the O-ring 52 is made to fit the O-ring of the first embodiment by fitting the hollow piston 44 to the piston guide member 45 and sliding the O-ring 52 to the inner peripheral surface of the hollow piston 44. Compared with the ring 34, the contact area becomes smaller and the sliding resistance is reduced. Therefore, it is easy to move with respect to a wide range of pressure fluctuations of the fuel, and it can cope with a wider range of pulsations. it can. The piston guide member 45 is provided with two seal members, O-rings 50 and 52, and is tightly sealed so that the fuel does not enter the air chamber 47. Therefore, the damper having excellent durability. Become a mechanism.

  The configuration of the fuel pipe connector housing 18 can be varied in the positional relationship between the male joint portion 21 and the female joint portion 21 and the cylinder portion 20 as in the first to fourth embodiments.

  The fuel pipe connector according to the present invention has been described with reference to the embodiment applied to the quick connector. However, the present invention can also be applied to pipe joints other than the quick connector.

  DESCRIPTION OF SYMBOLS 10 ... Connector for fuel piping, 12 ... Fuel tube, 14 ... Fuel piping, 16 ... Retainer, 18 ... Housing, 20 ... Cylinder part, 21 ... Male joint part, 22 ... Female joint part, 30 ... Cylinder, 31 ... Cylinder lid 32 ... Piston, 36 ... Air chamber, 38 ... Fuel chamber, 44 ... Hollow piston, 45 ... Piston guide member

Claims (14)

A connector used for pipe connection in a fuel pipe for supplying fuel to a fuel injection device,
A housing having a male joint to which a fuel tube is connected and a female joint to which a fuel pipe of the other party is connected;
A cylinder part formed integrally with the housing;
A piston having an outer peripheral portion with a seal member that is in sliding contact with the inner peripheral surface of the cylinder portion,
A fuel pipe connector characterized in that the piston is slidably accommodated in the cylinder portion, and a fuel chamber communicating with the fuel passage and an air chamber containing air are liquid-tightly partitioned by the piston. .   2. The fuel pipe according to claim 1, wherein a groove is formed in a circumferential direction on an outer peripheral portion of the piston, and a seal member that gives sliding resistance to the piston according to pressure fluctuation is fitted in the groove. connector.   2. The fuel pipe connector according to claim 1, wherein the seal member is formed of an O-ring capable of adjusting a width of a pressure fluctuation that can be absorbed by setting a sliding resistance depending on a compression ratio thereof. A connector used for pipe connection in a fuel pipe for supplying fuel to a fuel injection device,
A housing having a male joint to which a fuel tube is connected and a female joint to which a fuel pipe of the other party is connected;
A cylinder part formed integrally with the housing;
A hollow piston movable in the cylinder part;
A first guide member fixed to the inner peripheral surface of the cylinder portion and in contact with the inner peripheral surface of the cylinder portion; and a piston guide member having a second seal member in sliding contact with the inner peripheral surface of the piston, and
A fuel chamber communicating with the fuel passage is formed inside the piston guide member, and the fuel chamber and the air chamber sealed with air are liquid-tightly partitioned by the piston fitted on the piston guide member. A fuel pipe connector characterized by that.   The piston guide member includes a large-diameter portion that fits on the inner peripheral surface of the cylinder portion and a small-diameter portion that externally fits the hollow piston, and the first seal member is disposed on the outer peripheral portion of the large-diameter portion. The fuel pipe connector according to claim 4, wherein the second seal member is provided on an outer peripheral portion of the small diameter portion.   The first seal member is fitted into a groove formed in a circumferential direction on the outer peripheral surface of the large-diameter portion of the piston guide member, and a tapered surface is formed on the small-diameter portion side of the groove. 6. The fuel pipe connector according to claim 5, wherein an edge portion is formed in a tapered shape following the tapered surface.   The female joint portion of the housing is composed of a small cylindrical portion that forms a fuel passage, and a large cylindrical portion that is continuous with the small cylindrical portion via a stepped portion and receives a counterpart fuel pipe. The fuel pipe connector according to claim 1 or 5, comprising a cylindrical cylinder integrated with a small cylindrical portion, and a cylinder lid fixed to an end portion of the cylinder and sealing the air chamber. The inner diameter of the male joint portion is D1, the inner diameter of the opening communicating the fuel passage and the fuel chamber is D2, the inner diameter of the cylinder is D3, the inner diameter of the large diameter portion of the female joint portion is D4, and the inner diameter of the small diameter portion is D5. Sometimes between these inner diameters
D1 <D2 <D5 <D4 <D3
The fuel pipe connector according to claim 1, wherein:   5. The fuel pipe according to claim 1, wherein a biasing member that biases the piston toward the fuel chamber and regulates a movement amount of the piston is housed in the air chamber of the cylinder portion. Connector. 9. The fuel pipe connector according to claim 1, wherein air having a pressure in a range of 0.1 to 10 kgf / cm < ² > is sealed in the air chamber.   The cylinder portion includes a cylinder lid that is fixed to an end portion of the cylinder and has a through hole that opens the air chamber to the atmosphere, and includes a biasing member that absorbs fuel pressure fluctuations in response to movement of the piston. The fuel pipe connector according to claim 1, wherein the connector is contained in an air chamber.   5. The fuel pipe connector according to claim 4, wherein the second seal member includes an O-ring capable of adjusting a width of a pressure fluctuation that can be absorbed by setting a sliding resistance depending on a compression ratio thereof. .   The connector includes a male joint portion into which a fuel tube made of a resin or rubber is press-fitted, and a spool portion formed on the outer periphery of a counterpart fuel pipe by a retainer inserted into the housing, and the fuel pipe and the housing. The connector for fuel piping according to any one of claims 1 to 12, wherein the connector is a quick connector having a female joint portion that couples to each other.   14. The fuel pipe connector according to claim 13, wherein the quick connector connects the fuel tube extending to the vicinity of the engine and the fuel pipe for sending fuel to a fuel injection device.

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