JP2008208775A - Gasket for fuel injector and sealing-structure for injector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasket for a fuel injector and a sealing structure by which increase in the number of manufacturing steps can be avoided, and vibration control effect for the injector is improved. <P>SOLUTION: Between the injector 1 and a cylinder head 4, two stacked gaskets 8 are placed to seal the space between the injector 1 and the cylinder head 4. Either of the two gaskets 8 is constituted of an iron based material as a single material. When vibration is transmitted from the injector 1, the two gaskets 8 vibrate separately to rub together. Thus, vibration to be transmitted to the cylinder head 4 is reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injector gasket and an injector seal structure.

  In general, in an engine mounted on an automobile, it is desired to reduce noise generated during driving. And it is known that one of the causes of noise generated from the engine so far is that the fuel injector vibrates due to the internal needle moving up and down when fuel is injected from the fuel injector. . That is, when the fuel injector vibrates with the vibration of the needle, the fuel injector collides with the cylinder head, and the impact sound (sitting sound) becomes a noise source. Therefore, conventionally, in order to reduce the noise generated from the internal combustion engine, a gasket for a fuel injector having a damping performance against vibration generated from the fuel injector has been proposed (for example, see Patent Document 1).

In the fuel injector gasket described in Patent Document 1, a metal / rubber mixed sheet in which rubber is filled in a gap of a metal nonwoven fabric is provided, and a plurality of the metal / rubber mixed sheets are laminated. The And when manufacturing this metal / rubber mixed sheet, the rubber solution is impregnated into the metal nonwoven fabric according to the shape of the gasket product, and the rubber is filled into the voids of the metal nonwoven fabric, and then the rubber is heated and vulcanized and mixed sheet The entire heat compression molding is performed.
JP 2006-71015 A

  However, in the fuel injector gasket described in Patent Document 1, the metal / rubber mixed sheet formed by integrally molding the rubber and the metal nonwoven fabric includes a step of impregnating the metal nonwoven fabric with a rubber solution and heating the rubber. Manufacture is not possible without performing the step of performing heat compression molding of sulfur and mixed sheets. Therefore, since it is necessary to carry out an extra step to manufacture the fuel injector gasket described in Patent Document 1, it is disadvantageous from the viewpoint of manufacturing ease.

  The present invention has been made in view of the above problems, and an object of the present invention is to avoid an increase in the number of manufacturing steps and to improve a vibration reduction effect with respect to the vibration of the injector. And providing a seal structure.

  The invention according to claim 1 is a fuel injector gasket that is sandwiched between an injector and a cylinder head or an intake pipe and seals between the injector and the cylinder head or the intake pipe. The gist is that a plurality of formed annular gasket components are stacked one on top of another.

  In the present invention, a gasket formed by stacking a plurality of separate gasket components is sandwiched between an injector and a cylinder head or an intake pipe, and the gasket vibrates when fuel is injected from the injector. At this time, a plurality of gasket component parts individually vibrate to cause a shift between the gasket component parts, and the gasket component parts rub against each other to generate a frictional force. And the vibration transmitted to a cylinder head or an intake pipe can be reduced by generating a frictional force. Therefore, the vibration reduction effect exhibited by the gasket configured by stacking a plurality of gasket components can be improved as compared with a gasket configured by only one gasket component.

  Further, since the gasket component is made of a single material, the gasket can be produced simply by molding and stacking the gasket components. Therefore, since it is not necessary to perform a process of integrally molding a plurality of materials as in the case of forming a gasket from a composite material, the number of manufacturing steps is compared with a gasket configured by stacking a plurality of sheets made of a composite material. Can be reduced.

  The invention according to claim 2 is the invention according to claim 1, wherein the plurality of gasket component parts include a restricting means for restricting a relative position in the radial direction between the gasket component parts from deviating from a predetermined range. The gist is that it is provided.

  In the present invention, the relative position between the gasket components is regulated by the regulating means, and the gasket is sandwiched between the injector and the cylinder head or the intake pipe in a state where the relative positions of the gasket components are deviated from a predetermined range. Can be avoided. Therefore, even if the gasket is configured by superimposing a plurality of gasket components, it is possible to avoid a shift from a state where the gasket is mounted at a predetermined position, so that it is possible to suppress a deterioration in the sealing performance of the gasket.

The gist of the invention described in claim 3 is that, in the invention described in claim 2, a plurality of the gasket component parts have the same outer diameter.
In the present invention, if the outer diameters of the gasket components are the same, the gasket components can be overlapped so that a part of the gasket components is not covered.

  According to a fourth aspect of the present invention, in a seal structure for sealing between an injector and a cylinder head or an intake pipe, a plurality of gaskets formed from a single material are overlapped, and the stacked gaskets are combined with the injector and the injector. The gist is that it is arranged at a position sandwiched between the cylinder head or the intake pipe.

  In the present invention, a plurality of gaskets are overlapped and used by being sandwiched between an injector and a cylinder head or an intake pipe, and when a fuel injection is performed from the injector, the plurality of gaskets vibrate. At this time, the superposed gaskets vibrate separately in the radial direction, and each gasket rubs against an adjacent gasket to generate a frictional force, thereby reducing vibration transmitted to the cylinder head or the intake pipe. Therefore, the vibration transmitted from the injector to the cylinder head or the intake pipe can be reduced as compared with the case where only one gasket is sandwiched between the injector and the cylinder head or the intake pipe for sealing.

  Moreover, since the gasket formed from the single material is used, a gasket can be produced only by molding. Therefore, since it is not necessary to perform a process of integrally molding a plurality of materials as in the case of manufacturing a gasket made of a composite material, the number of manufacturing steps can be reduced compared to the case of manufacturing a gasket made of a composite material. .

  According to the present invention, it is possible to avoid an increase in the number of manufacturing steps and to improve the vibration reduction effect with respect to the vibration of the injector.

  Hereinafter, an embodiment in which the present invention is embodied as a gasket for sealing between a cylinder head of an automobile engine and an injector attached to the cylinder head will be described with reference to FIGS.

  As shown in FIG. 1, the injector 1 is used to add fuel to the combustion chamber 2 of the engine. The injector 1 passes through the clamp 3 and is clamped to the cylinder head 4 side by the clamp 3 and attached to the cylinder head 4 when the bolt 5 screwed into the cylinder head 4 constituting the engine is tightened.

  The injector 1 includes a main body 6 that receives a pressing force from the clamp 3 when the bolt 5 is tightened, and a nozzle 7 that is formed at the tip of the injector 1. The nozzle 7 is formed with a fuel injection hole (not shown) and two annular gaskets 8 are mounted on the outer periphery thereof.

  The gasket 8 as a gasket component is formed of a single material, and in this embodiment, is formed of an iron-based metal material. As shown in FIG. 2B, the inner diameter D1 of the gasket 8 is formed in such a size that a gap having a dimensional tolerance exists between the inner peripheral surface 9 and the nozzle 7, and the outer diameter d1 of the gasket 8 is set. Is formed to be smaller than the outer diameter of the main body 6.

  As shown in FIGS. 2A and 2B, the gasket 8 includes a seal portion 10 having the thickest portion, and an inner tapered portion 11 that becomes thinner from the seal portion 10 toward the inner peripheral side. And the outer side taper part 12 whose thickness becomes thin as it goes to the outer peripheral side from the seal part 10 is formed. Further, the seal portion 10 is provided with a first seal surface 13 and a second seal surface 14 that are orthogonal to the axial direction of the gasket 8, that is, the direction of the arrow Y 1 shown in FIG. Yes.

  When the injector 1 is attached to the cylinder head 4, as shown in FIG. 3, the nozzle 7 is inserted into the hole 15 of the cylinder head 4, and two gaskets 8 having the same shape are overlapped with the main body 6. It is sandwiched between the cylinder head 4 and seals between them. In this state, one of the two gaskets 8 is disposed on the cylinder head 4 side, and the other is disposed on the injector 1 side. The two gaskets 8 have the same outer diameter d1 and are overlapped along the axial direction of the gasket 8 so that the inner peripheral hole 16 of each gasket 8 and the center of the nozzle 7 coincide. Further, since the gasket 8 disposed on the injector 1 side is pressed by the injector 1, the second seal surface 14 of the gasket 8 facing the injector 1 is in contact with the injector 1 and the first of the gasket 8 facing the cylinder head 4. The seal surface 13 is in contact with the cylinder head 4. Therefore, the sealing performance between the cylinder head 4 and the injector 1 is ensured. In addition, the gasket 8 on the injector 1 side is pressure-bonded to the gasket 8 on the cylinder head 4 side, whereby the opposing seal surfaces 13 and 14 are in close contact with each other, and the sealing performance between the two gaskets 8 is ensured.

Next, the operation of the gasket 8 sandwiched between the injector 1 and the cylinder head 4 will be described.
When the engine is operated, the injector 1 vibrates to raise and lower a needle (not shown) in order to perform fuel injection, and vibrations in the radial direction and the axial direction are transmitted to each gasket 8. When vibration is transmitted to each gasket 8, each gasket 8 is a separate body and vibrates individually, so that the relative positions of the gaskets 8 in the radial direction are shifted. Therefore, the seal surfaces 13 and 14 of the gasket 8 that are in contact with each other rub against each other, and a frictional force is generated between the two gaskets 8. When a frictional force is generated between the two gaskets 8, the vibration energy included in the vibration applied to the gasket 8 is changed to heat, and the vibration transmitted to the cylinder head 4 is reduced.

  Further, as shown in FIG. 4, when the gasket 8 vibrates, the gasket 8 is elastically deformed in the radial direction (state shown by a two-dot chain line in FIG. 4) and the original state (state shown by a solid line in FIG. 4). ) And may change. At this time, a deviation H occurs in the radial direction of the gasket 8 between the two gaskets 8. Therefore, when each gasket 8 changes between a state in which it is elastically deformed in the radial direction and a normal state, the seal surfaces 13 and 14 that are in contact with each other rub against each other, and a frictional force is generated between the two gaskets 8. Arise. When a frictional force is generated between the two gaskets 8, the vibration energy included in the vibration applied to the gasket 8 is changed to heat, and the vibration transmitted to the cylinder head 4 is reduced.

  Therefore, in this embodiment, in addition to the vibration reduction effect that the two gaskets 8 originally have, a structure in which a frictional force is generated between the two gaskets 8 can provide a further vibration reduction effect. The vibration reducing effect can be improved. Therefore, vibration transmitted from the injector 1 to the cylinder head 4 is reduced, and noise generated from the engine can be reduced.

  Here, in order to evaluate the vibration reduction effect exhibited by the gasket 8, the following experiment was performed. In this experiment, a fixing jig is prepared instead of the cylinder block, the cylinder head 4 is mounted on the fixing jig, a gasket is sandwiched between the injector 1 and the cylinder head 4, and the injector 1 is attached to the cylinder head 4. Attached. In addition, the injector 1 was attached by pressing the injector 1 against the cylinder head 4 side with the clamp 3 as in the case of attaching to the actual machine. The force when the injector 1 is pressed against the cylinder head 4 side by the clamp 3 is set by the torque when tightening the bolt 5 that passes through the clamp 3 and is screwed into the cylinder head 4. Tightening was performed with a tightening torque of 25 [N · m]. Then, an exciting force 98N (10 kgf) is applied to the nozzle 7 portion of the injector 1 by the vibrator, and the force and acceleration applied to the cylinder head 4 through the gasket at that time are impedance heads attached to the cylinder head 4 Measured by. Next, a decibel value [dB] was calculated using the obtained measurement result and a calculation formula of dB = 20 log (Y / X). X is the excitation force applied to the injector, and Y is the excitation force calculated based on the force and acceleration measured by the impedance head.

  In this experiment, a gasket formed by superposing two gaskets 8 formed of iron-based metal and having an inner diameter D1 of 10 mm, an outer diameter d1 of 20 mm, and a maximum thickness of 1.5 mm is taken as an example. The experiment described above was performed. The experimental result is shown by a solid line in FIG. In addition, a single gasket having a maximum thickness of 3 mm is used as a comparative example, which is formed from an iron-based metal that is the same material as the gasket of the embodiment, and has the same inner diameter and outer diameter as the gasket of the embodiment. The experiment was conducted. The experimental result is shown by a two-dot chain line in FIG.

  Table 1 shows average values obtained by averaging the decibel value at 2 to 3 kHz, the decibel value at 3 to 4 kHz, and the decibel value at 2 to 4 kHz when the two gaskets 8 are overlapped. Similarly, in the case of a single gasket, Table 1 shows average values obtained by averaging the decibel value at 2 to 3 kHz, the decibel value at 3 to 4 kHz, and the decibel value at 2 to 4 kHz.

  Table 2 shows average values obtained by averaging the decibel values at 4 to 5 kHz, the decibel values at 5 to 6 kHz, and the decibel values at 4 to 6 kHz when the two gaskets 8 are configured to overlap each other. Similarly, in the case of a single gasket, Table 2 shows average values obtained by averaging the decibel value at 4 to 5 kHz, the decibel value at 5 to 6 kHz, and the decibel value at 4 to 6 kHz.

表１より、実施例のガスケットでは、２〜３ｋＨｚの振動、及び３〜４ｋＨｚの振動に対する振動低減効果は比較例のガスケットが発揮する振動低減効果とほぼ同様であることがわかった。

From Table 1, it was found that in the gasket of the example, the vibration reduction effect with respect to the vibration of 2 to 3 kHz and the vibration of 3 to 4 kHz is almost the same as the vibration reduction effect exhibited by the gasket of the comparative example.

  Moreover, from Table 2, the gasket of the example is 4.57 dB superior in vibration reduction effect with respect to vibration of 4 to 5 kHz as compared with the gasket of the comparative example, and the vibration reduction effect with respect to vibration of 5 to 6 kHz is compared with the gasket of the comparative example. It was found to be excellent by 5.61 dB. Therefore, the gasket of the example has a vibration reduction effect with respect to vibration of 2 to 4 kHz that is equivalent to the gasket of the comparative example, and exhibits a vibration reduction effect that is 5.09 dB larger than the gasket of the comparative example with respect to vibration of 4 to 6 kHz. I found out that

According to this embodiment, the following effects can be obtained.
(1) The two overlapped gaskets 8 are provided between the injector 1 and the cylinder head 4 and are sandwiched between the injector 1 and the cylinder head 4. Therefore, the vibration reducing effect exhibited by the two gaskets 8 can be improved.

  (2) The gasket 8 is formed from a single material. Therefore, since there is no need to perform a process of molding a plurality of materials integrally, for example, it is manufactured with fewer man-hours than when a gasket is formed from a composite material configured by filling rubber in the voids of a metal nonwoven fabric. can do.

  (3) The two gaskets 8 are both made of a metal material. Therefore, for example, higher heat conductivity can be obtained as compared with a gasket made of a composite material made of rubber and a metal nonwoven fabric. Further, if the gasket 8 is formed of a metal material, higher heat resistance can be obtained as compared with a gasket formed of a composite material made of rubber and a metal nonwoven fabric.

  (4) In the case of a gasket in which rubber is used as the material of the part to which the impact is applied, the deterioration progresses due to the impact applied from the injector in a high temperature state, and the sealing performance and the shock absorption performance are lowered. There is a high possibility that the function cannot be performed. However, if the gasket 8 is formed of a metal material, even if an impact is applied to the gasket 8 from the injector 1 in a high temperature state, the gasket 8 is excellent in heat resistance, so that the deterioration does not easily progress, and the durability of the gasket 8 is improved. .

The embodiment is not limited to the above, and may be embodied as follows, for example.
A restricting means for restricting the relative position in the radial direction of the gasket from deviating from a predetermined range may be provided on the gasket. For example, as shown in FIG. 6, a first gasket 17 and a second gasket 18 that are flat and have the same outer diameter are provided, and the second seal surface 17 a of the first gasket 17 is provided on the second seal surface 17 a. A protrusion 19 that makes a round along the inner periphery of the first gasket 17 may be provided, and a recess 20 having a diameter larger than that of the protrusion 19 may be provided in a portion of the first seal surface 18 a corresponding to the protrusion 19. The outer diameter of the protrusion 19 is made smaller than the diameter of the recess 20 so that the protrusion 19 is inserted into the recess 20 when the first gasket 17 and the second gasket 18 are overlapped. If comprised in this way, when the relative position of the radial direction of the 1st gasket 17 and the 2nd gasket 18 tends to shift | deviate from a predetermined range, the 1st gasket 17 and the protrusion 19 engage with the recessed part 20, and In order to restrict the movement of the second gasket 18, the protrusion 19 and the recess 20 are configured as a restricting means. Therefore, it is suppressed that the relative position in the radial direction between the first gasket 17 and the second gasket 18 deviates from a predetermined range. Therefore, even if it is a seal structure comprised by the 1st gasket 17 and the 2nd gasket 18 being piled up, it can suppress that the sealing performance of the gasket 8 is impaired. Moreover, the groove part which comprises a control means may be provided in the 2nd seal surface 17a, and the protrusion which comprises a control means may be provided in the 1st seal surface 18a. Even in this case, when the relative position of the first gasket 17 and the second gasket 18 in the radial direction is about to deviate from a predetermined range, the first gasket 17 and the second gasket 17 are engaged with the groove portion. Movement with the gasket 18 is restricted.

  O Of the two gaskets 8, the outer diameter d1 of one gasket 8 may be changed so that the outer diameters of the two gaskets 8 are different. For example, by making the outer diameter of the gasket 8 arranged on the cylinder head 4 side larger than the outer diameter of the gasket 8 arranged on the injector 1 side, the contact area between the gasket 8 and the cylinder head 4 is increased. The sealing performance with the head 4 may be improved. Further, by making the outer diameter of the gasket 8 arranged on the injector 1 side larger than the outer diameter of the gasket 8 arranged on the cylinder head 4 side, the contact area between the gasket 8 and the injector 1 is increased, and the gasket 8 and the injector 1 are increased. The sealing property may be improved.

  ○ Three or more gasket components may be stacked to form a gasket. For example, three gaskets 8 as gasket components may be prepared, and the three gaskets 8 may be overlapped.

  ○ The material constituting the gasket 8 may be changed. For example, the gasket 8 may be made of a copper material. Moreover, you may comprise the gasket 8 with a ceramic material instead of comprising with a metal material.

  ○ The shape of the gasket 8 may be changed. For example, the gasket 8 may be formed in a flat plate shape without a taper portion. Moreover, you may form the gasket 8 in planar view elliptical shape or planar view polygonal shape, respectively.

  O Instead of using the gasket 8 for the injector 1 attached to the cylinder head 4, it may be used for the injector 1 attached to the intake pipe. In this case, when the injector 1 is attached to the intake pipe with the nozzle 7 of the injector 1 being inserted into the hole of the intake pipe, the gasket is used by being sandwiched between the injector 1 and the intake pipe.

  ○ Instead of providing the gasket of the present invention between the cylinder head and the injector of an automobile engine, the present invention may be used between the cylinder head and the injector of a railway car engine or between the cylinder head and the injector of a generator engine. An inventive gasket may be provided.

Sectional drawing which shows the attachment structure to the engine of the injector to which the gasket of this embodiment is applied. (A) is a perspective view of a gasket, (b) is a sectional side view in a state where two gaskets are overlapped. The expanded sectional view which shows the state where two gaskets were pinched | interposed into the injector and the cylinder head. The schematic diagram which shows the state of a gasket when vibration is added. The graph which shows the relationship between the frequency of the vibration applied to a gasket, and decibel. The sectional side view of the gasket in another embodiment.

Explanation of symbols

  d1 ... outer diameter, 1 ... injector, 4 ... cylinder head, 8 ... gasket as a gasket component, 13 ... first seal surface, 14 ... second seal surface, 19 ... projection as a restriction means, 20 ... regulation means As a recess.

Claims (4)

In a fuel injector gasket that is sandwiched between an injector and a cylinder head or an intake pipe and seals between the injector and the cylinder head or the intake pipe,
A fuel injector gasket comprising a plurality of annular gasket components formed from a single material. The gasket according to claim 1, wherein each of the plurality of gasket component parts is provided with a restricting unit that restricts a relative position in the radial direction between the gasket component parts from deviating from a predetermined range. The gasket according to claim 2, wherein the plurality of gasket components have the same outer diameter. In the seal structure that seals between the injector and the cylinder head or the intake pipe,
A seal structure for an injector in which a plurality of gaskets made of a single material are stacked, and the stacked gaskets are arranged at positions sandwiched between the injector and the cylinder head or the intake pipe.

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