JP4710944B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve used in an internal combustion engine.

In general, a fuel injection valve is attached to an internal combustion engine so that a nozzle portion at the tip is located at a predetermined gap along an attachment hole communicating with the combustion chamber of the internal combustion engine, and the nozzle portion is used for high-temperature combustion gas in the combustion chamber. Be exposed. For this reason, when the temperature of the nozzle part rises and the fuel inside the nozzle part remains, the deposit adheres to the inside of the nozzle part and the nozzle hole, resulting in a problem that the fuel injection amount decreases.

In order to solve this problem, in Patent Document 1 below, as shown in FIG. 5, a metal spring seal 14 is attached to the tip of the nozzle portion 8 and is brought into contact with the inner periphery of the mounting hole of the engine head 15. Area where the combustion gas is prevented from entering and exposed to the combustion gas of the nozzle portion 8 (length in the axial direction)
A method is described in which the temperature at the tip of the nozzle portion 8 is reduced to reduce deposits and to prevent deposit adhesion.

However, in the deposit adhesion suppression method described in Patent Document 1 below, the metal spring seal 14 is exposed to the combustion gas, so that the metal spring seal 14 becomes hot and thermally deforms, and the combustion gas may leak up to the upper portion of the nozzle portion 8. At that time, since the washer 16 for adjusting the mounting position of the fuel injection valve and the engine head 15 is installed on the flange portion of the retailing nut 7, the distance from the tip of the nozzle portion 8 is increased, and the side surface of the nozzle portion 8 is increased. The part is exposed to the combustion gas, and the temperature rise at the tip of the nozzle part 8 cannot be suppressed.

Further, in Patent Document 2 below, as shown in FIGS. 1 and 7, an annular groove 16 is formed at the tip of the nozzle portion 12 (fuel injection valve body), and two annular grooves 16 are formed in the annular groove 16. Metal ring members 17A and 17B are attached to prevent the intrusion of combustion gas.

However, the inner diameter of the two metal ring members 17A and 17B must be smaller than the outer shape of the nozzle portion 12 in order to be accommodated in the annular groove 16, and the metal ring members 17A and 17A for mounting on the nozzle portion 12 17B is provided with a notch (slit) 17C.

When the metal ring members 17A and 17B are accommodated in the annular groove 16, the notches 17C are shifted from each other so as to maintain the sealing performance. However, the high-temperature and high-pressure combustion gas removes one notch from the other notch. It is difficult to pass through and leak to the upper part of the nozzle part to ensure sufficient sealing of the combustion gas.

The members for sealing the combustion gas are the metal spring seal 14 in the following Patent Document 1 and the metal rings 17A and 17B in the following Patent Document 2, both of which are made of metal, and the fuel injection valve is used as a mounting hole of the internal combustion engine. When mounting, there is a concern that this metal seal member may damage the inner wall of the mounting hole and deteriorate the sealing performance of the combustion gas.
JP-A-9-310660 Japanese Patent Application Laid-Open No. 9-126089

The present invention has been made in view of the above points. An annular heat-resistant seal member that is in contact with the inner peripheral portion of the mounting hole of the internal combustion engine is attached to the outer peripheral portion of the tip portion of the nozzle portion. By mounting an annular heat-resistant protective member having an exposed portion that covers the exposed surface of the seal member on the tip side further from the mounting position, the annular heat-resistant protective member prevents melting damage of the annular heat-resistant seal member. The intrusion of combustion gas can be suppressed by the seal member, and as a result, the temperature rise of the nozzle portion is suppressed to prevent deposits from being generated and adhered in the nozzle portion.

In the invention according to claim 1, the nozzle portion is mounted on the internal combustion engine so as to be positioned with a predetermined gap from the inner peripheral portion of the mounting hole along the mounting hole communicating with the combustion chamber of the internal combustion engine. An annular heat-resistant sealing member that is attached to the outer peripheral portion on the tip side of the nozzle portion and contacts the inner peripheral portion of the mounting hole, and is attached to the tip side further than the mounting position of the annular heat-resistant seal member by obtaining Bei an annular heat-resistant protective member having an exposed protective portion covering the tip side of the annular heat seal.
Further, the annular heat resistant seal member and the annular heat resistant protective member are made of different materials, and the annular heat resistant protective member is a heat resistant elastic metal member having a higher melting point than the annular heat resistant seal member,
The annular heat-resistant seal member and the annular heat-resistant protective member are mounted in an annular groove formed in the outer peripheral portion on the tip side of the nozzle portion, and the annular heat-resistant seal is provided in the annular heat-resistant seal member and the annular heat-resistant protective member. The rear end side of only the member is in contact with the rear end side step portion of the groove, and the exposure area A1 of the exposure protection portion of the annular heat resistant protection member is set larger than the exposure area A2 of the exposure portion of the annular heat resistant seal member. It is characterized by being.

According to the above configuration, the annular heat resistant seal member can be prevented from being melted by the exposure protection portion of the annular heat resistant protective member, and the annular heat resistant seal member can prevent the combustion gas from entering the rear end side of the nozzle portion. As a result, the temperature rise of the nozzle part is suppressed to prevent deposits from being generated and adhered in the nozzle part.

According to the above configuration, the annular heat-resistant sealing member (hereinafter appropriately referred to as the annular sealing member) can be prevented from being melted from the high-temperature combustion gas.
Furthermore, since the pressure to the rear end side of the exposed protection portion of the annular heat resistant protective member by the combustion gas is larger than the pressure to the rear end portion of the exposed portion of the annular heat resistant seal member, the annular heat resistant protective member is always provided. Is in close contact with the annular heat-resistant sealing member, and combustion gas can be prevented from entering the gap between the annular heat-resistant protecting member and the annular heat-resistant sealing member.

The invention according to claim 2 is characterized in that the annular heat-resistant sealing member has a lower hardness than the material of the mounting hole portion of the internal combustion engine.

  According to the above configuration, when the fuel injection valve is attached to the mounting hole of the internal combustion engine, the annular heat resistant seal member can prevent the inner wall of the mounting hole from being damaged.

The invention according to claim 3 is characterized in that the annular heat-resistant protective member is made of stainless steel and the annular heat-resistant sealing member is made of polytetrafluoroethylene material.

According to the above configuration, the annular heat-resistant sealing member made of stainless steel reliably prevents the annular heat-resistant sealing member from being melted from a high-temperature combustion gas and reliably maintains the combustion performance of the annular heat-resistant sealing member. it can.

The invention according to claim 4 is characterized in that the annular heat-resistant protective member is provided with a position stable holding portion extending in the front-rear direction.

According to the above configuration, when the annular heat-resistant protective member is attached to the annular groove portion of the outer peripheral portion of the nozzle portion by the position stable holding portion, the annular heat-resistant protective member is scattered with respect to the nozzle portion. Stable position can be maintained.

In the invention which concerns on Claim 5 , the said position stable holding | maintenance part is arrange | positioned inside the said annular heat resistant sealing member, It is characterized by the above-mentioned.

According to the above configuration, the annular heat-resistant protective member does not contact the outer peripheral portion of the nozzle portion made of metal or the inner peripheral surface of the mounting hole of the internal combustion engine, and the annular seal member is in contact with the outer peripheral portion of the nozzle portion. Since it abuts on the inner peripheral surface of the mounting hole of the internal combustion engine, the sealing performance can be ensured.

In the invention which concerns on Claim 6 , length L1 of the said position stable holding | maintenance part from the exposure protection part front end side of the said heat resistant protection member is set to the said cyclic | annular heat resistant seal member from the exposure protection part front end side of the said annular heat resistance protection member. It is characterized by being set shorter than the length L2.

  According to the above configuration, when the combustion gas enters the combustion gas introduction space portion of the annular groove portion, the rear end side of the position stabilizing holding portion does not contact the rear end side step portion of the annular groove portion, and the exposure protection portion is annular. It can be in close contact with the front end surface of the seal member to prevent the combustion gas from entering the front end surface and prevent the annular seal member from being melted.

In the invention which concerns on Claim 7 , the said cyclic | annular heat-resistant protective member is connected to the two axial direction division | segmentation surfaces which pass the axis line, and the two axis lines which connect with the said two axial direction division | segmentation surfaces and are orthogonal to the said two axial direction division | segmentation surfaces A two-division structure divided by an orthogonal direction dividing surface and two axial parallel direction dividing surfaces connected to the two axial orthogonal direction dividing surfaces and parallel to the two axial direction dividing surfaces, and the two axial orthogonal directions The other surface in which the two axial orthogonal divided surfaces are recessed from the two axial divided surfaces is the exposure area S1 of one divided convex divided piece protruding from the two axial divided surfaces. It is characterized by being set to be larger than the exposure area S2 in the divided concave divided piece.

  According to the said structure, since the said cyclic | annular heat-resistant protection member is made into 2 division structure, mounting | wearing to the cyclic | annular groove part of the said nozzle part is easy, and the exposure area S1 of the said convex division piece is made into the said concave division piece. Since it is set to be larger than the exposure area S2, the combustion gas pressure acting on the convex divided piece is always larger than the combustion gas pressure acting on the concave divided piece, and therefore, the two axes of the convex divided piece. The orthogonal dividing surface is always kept in close contact with the two axial orthogonal dividing surfaces of the concave divided piece, and combustion gas does not leak from the dividing surfaces of the two divided pieces.

In the invention which concerns on Claim 8 , the said cyclic | annular heat resistant protection member is comprised only by the exposure protection part extended in radial direction, It is characterized by the above-mentioned.

According to the above configuration, the annular heat-resistant protective member has a very simple shape, is easy to manufacture and is inexpensive, and the annular seal member contacts the outer peripheral portion of the nozzle portion and the inner peripheral portion of the mounting hole. Therefore, sealing can be performed reliably.

The invention according to claim 9 is characterized in that the annular heat-resistant protective member is sandwiched between the annular heat-resistant sealing member and a stepped side portion of the annular groove portion of the nozzle portion.

According to the said structure, when attaching the said annular heat resistant protection member to the annular groove part of the said nozzle part, the said annular heat resistant protective member is prevented from inclining, and attachment property improves.

In the invention which concerns on Claim 10 , the outer diameter length D1 of the exposure protection part of the said cyclic | annular heat resistant protection member is set shorter than the internal diameter D2 of the attachment hole of the said internal combustion engine, It is characterized by the above-mentioned.

According to the above configuration, when setting the fuel injection valve in a state where the annular heat-resistant protective member is mounted on the tip side of the nozzle portion in the mounting hole of the internal combustion engine, the exposure protective portion of the annular heat-resistant protective member The tip does not contact the inner periphery of the mounting hole, and therefore the inner periphery of the mounting hole is not damaged, and the fuel injection valve can be set smoothly.

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment. FIG. 1 is a cross-sectional view showing a main part of the fuel injection valve 1, and FIG. 2 is an enlarged cross-sectional view of a portion X in FIG. In the specification, the “front end side” is a side located on the combustion chamber 11 side of the internal combustion engine 8 described later as shown in FIG. 1, and the “rear end side” is the opposite side of the “front end side”. .

A needle 3 that is slid in the axial direction by a drive body such as an electromagnetic solenoid or a piezo element (not shown) and a control valve mechanism is disposed inside the nozzle portion 2 located on the tip side of the fuel injection valve 1. The high-pressure fuel supplied to the internal space 4 of the nozzle portion 2 by the sliding of the needle 3 is injected / blocked from the nozzle holes 5 and 6 on the tip side of the nozzle portion 2.

The rear end side of the nozzle portion 2 is assembled by a retaining nut 7 in contact with a body member (not shown) to form the fuel injection valve 1. The fuel injection valve 1 is connected to the head of the internal combustion engine 8 through the gasket 9 at the flange portion of the retaining nut 7, and the mounting hole 10 and the outside are arranged so that the nozzle portion 2 extends along the mounting hole 10 of the head of the internal combustion engine 8. Can be installed by blocking. The attachment hole 10 communicates with the combustion chamber 11 of the internal combustion engine 8 and high-temperature and high-pressure combustion gas enters. In the present invention, the annular seal member 12 and the annular heat-resistant protective member 13 described later prevent the combustion gas from entering the rear end side of the outer peripheral portion 2a of the nozzle portion 2.

Next, the mounting structure of the annular seal member 12 and the annular heat-resistant protective member 13 on the nozzle portion 2 will be described with reference to FIG. An annular groove portion 2b is formed in the outer peripheral portion 2a on the tip side of the nozzle portion 2, and the annular groove portion 2b has a rectangular cross-sectional shape and a heat-resistant annular seal member 12 such as polytetrafluoroethylene and a meat. An annular heat-resistant protective member 13 of an elastic member made of a heat-resistant elastic metal such as stainless steel whose cross-sectional shape is L-shaped is mounted, and the annular heat-resistant protective member 13 is on the tip side of the annular seal member 12, that is, the combustion chamber. It is arrange | positioned so that it may be located in 11 side. The annular heat-resistant protective member 13 is provided with a notch (slit) (not shown), and the notch can be slightly opened to be attached to the annular groove 2b of the nozzle part 2. The material of the annular seal member 12 is elastic from the viewpoint of having a sealing function, and can be mounted outside the annular heat-resistant protective member 13 by increasing its diameter in an annular state. An example of the annular heat-resistant protective member 13 will be described later with reference to FIGS.

The annular heat-resistant protective member 13 is L-shaped in cross section, but the radial portion covers the distal end side surface 12b of the annular seal member 12 and presents an exposure protection portion 13a that protects it from being exposed to combustion gas. A portion connected to the exposure protection portion 13a and extending in the front-rear (axial) direction along the annular groove portion 2b forms a position stable holding portion 13b. The outer diameter length D1 of the exposure protection part 13a is set slightly shorter than the inner diameter D2 of the mounting hole 10. That is, the outer diameter of the exposure protection part 13a is the mounting hole 10
It is not in contact with the inner diameter.

The annular seal member 12 is disposed on the outer periphery of the position stable holding portion 13b of the annular heat-resistant protective member 13, and the rear end side thereof is in contact with the rear end side step portion 2e of the annular groove portion 2b. The tip side surface 12b is in contact with the exposure protection part 13a of the annular heat-resistant protection member 13 and is mostly covered by the exposure protection part 13a.

The length L1 of the position stable holding portion 13b from the distal end side of the exposure protection portion 13a of the annular heat resistant protection member 13 is shorter than the length L2 of the annular seal member 12 from the distal end side of the exposure protection portion 13a of the annular heat resistance protection member 13. The rear end side of the position stability holding portion 13b is not in contact with the rear end side step portion 2e of the annular groove portion 2b. That is, only the annular seal member 12 is the rear end side step portion 2 of the annular groove portion 2b.
It is set to abut against e.

Further, the step portion 2c on the front end side of the annular groove portion 2b is notched in the radial direction to provide a combustion gas introduction space portion 2d, and the combustion gas is introduced into the combustion gas introduction space portion 2d. In addition, although the step part 2c is cyclically provided over the entire circumference in the annular groove part 2b, it may be partially provided in a part of the entire circumference, for example, four places. In this case, the area of the exposure protection part 13a is increased. can do.

Further, the annular exposure area A1 of the exposed protection portion 13a portion of the annular heat-resistant protective member 13 is set to be considerably larger than the annular exposure area A2 of the exposed portion 12a of the annular seal member 12. The combustion gas pressure acts on the exposure protection part 13a having a large area to press the annular heat-resistant protection member 13 toward the rear end side,
While acting so as to be always in close contact with the annular seal member 12, the exposure protection portion 13a covers most of the tip side of the annular seal member 12 to prevent melting loss due to combustion gas. The annular exposure area A2 of the exposed portion 12a of the annular seal member 12 is the exposure protected portion 13a of the annular heat-resistant protective member 13.
Since it is much smaller than the annular exposure area A1 of the portion, the annular seal member 12 has heat resistance and can withstand melting damage.

When the annular exposed area A2 of the exposed portion 12a of the annular seal member 12 is set larger than the annular exposed area A1 of the exposed protected portion 13a portion of the annular heat-resistant protective member 13, the annular seal member 12 is pressed to the rear end side. The force to perform is superior to the force to press the annular heat-resistant protective member 13, and a slight gap is formed between the two, and the combustion gas enters the gap, and the exposed portion 12 a of the annular seal member 12.
Since the annular exposure area A2 is large, the annular seal member 12 may be melted.

  Next, an embodiment of the annular heat-resistant protective member 13 will be described with reference to FIGS. As shown in FIGS. 6 and 7, the annular heat-resistant protective member 13 having the exposure protection part 13a and the position stable holding part 13b has a two-part structure. The two-part structure is composed of a convex part 13c and a concave part 13d.

  The convex segment 13c and the concave segment 13d connect the annular heat-resistant protective member 13 to the two axial segmented surfaces 13e passing through the axis (center line) X and the two axial segmented surfaces 13e, respectively. Two axis-orthogonal direction dividing surfaces 13f perpendicular to (extend in the circumferential direction) the two axis-direction dividing surfaces 13e, and these two axis-orthogonal direction dividing surfaces 13f are connected to and parallel to the two axial-direction dividing surfaces 13e. It is divided and formed by two axial parallel direction dividing surfaces 13g.

  As shown in FIGS. 6 and 7 (right-side piece), the convex divided piece 13c has two axis-orthogonal direction dividing surfaces 13f protruding in the circumferential direction from the two axial direction dividing surfaces 13e, and two axis-parallel direction dividing surfaces. As shown in FIGS. 6 and 7 (left side piece), the two axis-orthogonal direction dividing surfaces 13f are two axis-convex dividing pieces 13c in the line-direction dividing surface. A convex shape is formed that is recessed (recessed) in the circumferential direction from 13e and connected to two axially parallel dividing surfaces 13g.

  The convex divided piece 13c and the concave divided piece 13d are integrated to form the annular heat-resistant protective member 13 by combining the two axial direction divided surfaces 13e, the axis orthogonal direction divided surface 13f, and the axis parallel direction divided surface 13g.

  Further, since the convex divided piece 13c and the concave divided piece 13d are formed as described above, the convex divided piece exposure area S1 of the exposure protection portion 13a in the convex divided piece 13c is the exposure protection in the concave divided piece 13d. It becomes larger than the concave divided piece exposure area S2 of the part 13a (S1> S2). Here, the convex divided piece exposure area S1 and the concave divided piece exposure area S2 are the areas of the portion directly exposed to the combustion gas, and the tip side of the annular groove 2b of the nozzle portion 2 as shown by the shaded pattern in FIG. It is the area of the part except the area of the part contact | abutted to the step part 2c. That is, the annular exposure area A1 of the exposure protection part 13a = the convex divided piece exposed area S1 + the concave divided piece exposed area S2. Furthermore, the annular exposure area A2 of the exposed portion 12a of the annular seal member 12 is set to be smaller than the concave divided piece exposure area S2. That is, the annular exposure area A2 <the concave divided piece exposed area S2 <the convex divided piece exposed area S1.

As a procedure for mounting the fuel injection valve 1 according to the present invention on the internal combustion engine 8, the convex divided piece 13 c and the concave divided piece 13 d are set from the outside of the annular groove 2 b formed on the tip side of the nozzle portion 2. The annular heat-resistant protective member 13 is configured by combining the axial-direction divided surface 13e, the axial-orthogonal-direction divided surface 13f, and the axial-parallel-direction divided surface 13g, and then the annular heat-resistant protective member 13 is mounted. The fuel injection valve 1 fitted with the annular heat-resistant protective member 13 and the annular seal member 12 is inserted into the mounting hole 10 of the internal combustion engine 8 from the nozzle portion 2 and the fuel injection valve 1 is inserted. Attached to the internal combustion engine 8. In the mounted state, the groove portion 2b of the nozzle portion 2, the heat resistant protection member 13, the annular seal member 12, and the inner peripheral portion 10a of the mounting hole 10 are in contact with each other in the radial direction. As a result, the combustion gas can be prevented from entering the rear end side of the outer peripheral portion 2a of the nozzle portion 2.

As described above, in the first embodiment of the present invention, the nozzle portion 2 is positioned along the mounting hole 10 communicating with the combustion chamber 11 of the internal combustion engine 8 while maintaining a predetermined gap with the inner peripheral portion 10a of the mounting hole 10. The fuel injection valve 1 mounted on the internal combustion engine 8 includes an annular seal member 12 mounted on the outer peripheral portion 2a on the tip end side of the nozzle portion 2 and abutting on the inner peripheral portion 10a of the mounting hole 10, and an annular seal member 12 The exposure protection unit 1 that is mounted on the tip side further than the mounting position and covers the tip side surface 12a of the seal member 12.
Since the annular heat-resistant protective member 13 having 3a is provided, the annular heat-resistant seal member 12 is prevented from being melted by the exposure protection portion 13a of the annular heat-resistant protective member 13, and the annular heat-resistant seal member 12 is provided.
Thus, it is possible to prevent the combustion gas from entering the rear end side of the nozzle portion 2, thereby suppressing the temperature rise of the nozzle portion 2 and preventing deposits from being generated and deposited in the nozzle portion.

Further, the annular seal member 12 and the annular heat-resistant protective member 13 are mounted in an annular groove 2b formed in the outer peripheral portion 2a on the tip side of the nozzle portion 2, and in the annular seal member 12 and the annular heat-resistant protective member 13 Only the annular seal member 12 has a rear end side on the rear end side step portion 2e on the groove portion 2b.
Since the annular exposure area A1 of the exposure protection part 13a of the annular heat resistant protection member 13 is set larger than the exposure area A2 of the exposure part 12a of the annular seal member 12, the annular heat resistance protection by the combustion gas is performed. The pressure on the rear end side of the exposure protection portion 13a of the member 13 is increased by the annular seal member 12
Therefore, the annular heat-resistant protective member 13 is always in close contact with the annular seal member 12, and combustion gas is generated between the annular heat-resistant protective member 13 and the annular seal member 12. Intrusion into the gap can be prevented.

Further, since the annular heat-resistant protective member 13 is provided with a position stable holding portion 13b extending in the front-rear direction, the annular heat-resistant protective member 13 is attached to the annular groove portion of the outer peripheral portion 2a of the nozzle portion 2 by the position stable holding portion 13b. When mounted on 2b, the annular heat-resistant protective member 13 can be held in a stable position without being swayed with respect to the nozzle portion 2.

Further, since the outer diameter length D1 of the exposure protection portion 13a of the annular heat resistant protection member 13 is set shorter than the inner diameter D2 of the mounting hole 10 of the internal combustion engine 8, the annular heat resistant protection member 13 serves as the tip of the nozzle portion 2. When the fuel injection valve 1 mounted on the side is set in the mounting hole 10 of the internal combustion engine 8, the tip of the exposure protection part 13a of the annular heat-resistant protective member 13 does not contact the inner periphery 10a of the mounting hole 10, Therefore, the fuel injection valve 1 can be set smoothly without scratching the inner periphery 10a of the mounting hole 10.

  Further, since the annular heat-resistant protective member 13 is made of a refractory metal material rather than the annular seal member 12, the annular seal member 12 can be prevented from being melted from a high-temperature combustion gas.

  Further, since the material of the annular seal member 12 is lower in hardness than the material of the attachment hole 10 portion of the internal combustion engine 8, when the fuel injection valve 1 is attached to the attachment hole 10, the annular seal member 12 causes the attachment hole 10. The inner wall is not damaged.

  Further, the length L1 of the position stable holding portion 13b from the distal end side of the exposure protection portion 13a of the heat resistant protection member 13 is longer than the length L2 of the annular seal member 12 from the distal end side of the exposure protection portion 13a of the annular heat resistance protection member 13. Since it is set short, when the combustion gas enters the combustion gas introduction space 2d of the annular groove 2b, the rear end side of the position stabilizing holding portion 13b does not contact the rear end side step 2e of the annular groove 2b. The exposure protection part 13a is in close contact with the front end surface 12b of the annular seal member 12 and prevents the combustion gas from entering the front end surface 12b, thereby preventing the annular seal member 12 from being melted.

  In addition, since the heat-resistant protective member 13 has a two-part structure composed of the convex divided piece 13c and the concave divided piece 13d, the set mounting of the nozzle part 2 on the annular groove part 2b can be performed very easily. In this case, even if the heat-resistant protective member 13 has a two-divided structure of the convex divided piece 13c and the concave divided piece 13d, the convex divided piece exposure area S1 in the convex divided piece 13c is the concave divided piece in the concave divided piece 13d. Since it is larger than the exposed area S2, as shown in FIG. 8, the convex divided piece pressing force F1 that the combustion gas acts on the convex divided piece exposed area S1 is the concave divided piece pressed force F2 that acts on the concave divided piece exposed area S2. Since it becomes larger (F1> F2), the two axis-orthogonal direction dividing surfaces 13f of the convex divided piece 13c are always in close contact with the two axis-orthogonal direction dividing surfaces 13f of the concave divided piece 13d, and the two axis-orthogonal direction dividing surfaces are divided. The combustion gas can be prevented from leaking to the inside (rear end side) of the mounting hole 10 by the surface 13f. In addition, in FIG. 8, the internal structure of the nozzle part 2 is abbreviate | omitted from a viewpoint which clarifies description of the 2 division structure of the heat resistant protective member 13. In FIG. The internal structure of the nozzle part 2 is the same as the structure described in FIG.

The difference D between the exposed area A2 of the exposed portion 12a of the annular seal member 12, that is, the inner diameter D2 of the mounting hole 10 of the internal combustion engine 8 and the outer diameter length D1 of the exposed protective portion 13a of the annular heat-resistant protective member 13.
2-D1 is desirably as small as possible from the viewpoint of preventing the annular seal member 12 from being melted.

Next, second, third, and fourth embodiments will be described with reference to FIGS. 3, 4, and 5. In the second, third, and fourth embodiments, only the feature points and differences will be described. 3, 4, and 5 are all shown in FIG. 1.
The part corresponding to the X part is shown.

In the second embodiment shown in FIG. 3, the cross-sectional shape of the meat portion of the annular heat-resistant protective member 13 is inverted T-shaped, and the annular seal member 12 has a small-diameter annular seal member 12 c and a large-diameter annular seal 12 having different inner diameters.
It is an example of the seal structure divided | segmented into d.

The position stable holding portion 13b extending in the front-rear direction of the annular heat-resistant protective member 13 is the annular seal member 1.
2, that is, sandwiched between the small-diameter annular seal member 12c and the large-diameter annular seal 12d. The rear end sides of the small-diameter annular seal member 12c and the large-diameter annular seal 12d are in contact with the rear end side step portion 2e of the groove 2b, and the front end side surface 12b is in contact with and covered with the exposure protection portion 13a of the annular heat-resistant protection member 13. ing. Other dimensions and area relationships are the same as those described in FIG. The annular heat-resistant protective member 13 in the second embodiment shown in FIG. 3 may have the two-part structure described in the first embodiment.

In the invention of the second embodiment shown in FIG. 3, in addition to the common effects in the first embodiment, the position stable holding portion 13 b of the annular heat-resistant protective member 13 is arranged inside the annular seal member 12. Since the annular seal member 12 contacts the outer peripheral portion 2a of the nozzle portion 2 and the inner peripheral surface 10a of the mounting hole 10 of the internal combustion engine 8, the sealing performance can be reliably performed. Even if the annular heat-resistant protective member 13 is made of metal, it does not come into contact with the inner peripheral surface 10a of the mounting hole 10 of the internal combustion engine 8, so that the inner peripheral surface 10a is not damaged during mounting.

In the third embodiment shown in FIG. 4, the annular heat-resistant protection member 13 is configured only by the exposure protection portion 13 a extending in the radial direction (the position stabilizing holding portion 13 b is eliminated), and the annular seal member 12 is formed in the groove portion of the nozzle portion 2. This is an example in which both 2b and the inner peripheral surface 10a of the mounting hole 10 are brought into contact with each other. As shown in the drawing, the inner diameter side portion of the annular heat-resistant protective member 13 is sandwiched between the annular seal member 12 and the tip side step portion 2 c of the annular groove portion 2 b of the nozzle portion 2. Other dimensions and area relationships are the same as those described in FIG.

According to the invention of the third embodiment, in addition to the common effects in the first and second embodiments, the structure of the annular heat-resistant protective member 13 is simple, easy to manufacture and inexpensive. Moreover, the sealing effect by the annular seal member 12 can be reliably performed. Further, since the annular heat-resistant protective member 13 is sandwiched between the annular seal member 12 and the tip side step 2c of the annular groove 2b of the nozzle portion 2, the annular heat-resistant protective member 13 is attached to the annular groove 2b of the nozzle portion 2. At this time, the annular heat-resistant protective member 13 is prevented from being tilted, and the mountability is improved.

In the fourth embodiment shown in FIG. 5, the annular heat-resistant protective member 13 is composed only of the exposure protection portion 13a extending in the radial direction (the position stable holding portion 13b is eliminated), and the outer diameter D1 of the exposure protection portion 13a is attached. In this example, the hole 10 is set to have substantially the same dimension as the inner diameter D2 (where D2> D1). That is, this is an example in which the exposed protection part 13a of the annular heat-resistant protective member 13 covers almost the entire front end surface 12 of the annular seal member 12 (an example in which the exposed part 12a is eliminated). As shown in the drawing, the inner diameter side portion of the annular heat-resistant protective member 13 is sandwiched between the annular seal member 12 and the tip side step portion 2 c of the annular groove portion 2 b of the nozzle portion 2. Other dimensions and area relationships are the same as those described with reference to FIGS.

According to the invention of the fourth embodiment, in addition to the common effects in the first to third embodiments, the annular seal member 12 is entirely covered with the exposure protection part 13a of the heat-resistant protective member 13, and the heat-resistant protective member 1 is covered.
3 and the annular seal member 12 in the front-rear direction has the greatest adhesion force.
2 can be surely prevented from being melted, and the sealing effect can also be reliably achieved. Moreover, in 4th Embodiment, although the difference of the outer diameter D1 of the exposure protection part 13a of the heat-resistant protective member 13 and the internal diameter D2 of the attachment hole 10 is small, when attaching the heat-resistant protective member 13, it is based on this slight clearance. The inclination of the heat-resistant protective member 13 can be reliably prevented by being sandwiched between the annular seal member 12 and the tip side step portion 2c of the annular groove portion 2b of the nozzle portion 2.

In the first to third embodiments, the outer diameter D1 of the exposure protection portion 13a of the heat-resistant protection member 13 is smaller than the inner diameter D2 of the mounting hole 10, and a slight exposure portion is formed on the tip side surface 12b of the annular seal member 12. In this case, the outer diameter D1 of the exposure protection portion 13a is substantially the same as the inner diameter D2 of the mounting hole 10 (however, D2> D1).
May be set.

In the above embodiment, the heat-resistant protective member 13 is an example of stainless steel as a heat-resistant elastic member, but it may be made of ceramic having heat resistance. In this case, since the ceramic product lacks elasticity, the nozzle portion 2 is transversely cut at the front end side step portion 2c or the rear end side step portion 2e of the annular groove portion 2b, attached to the annular groove portion 2b, and then connected. A ceramic heat-resistant protective member 13 may be attached to the distal end side.

It is principal part sectional drawing which shows 1st Embodiment of this invention fuel injection valve. It is an expanded sectional view of the X section of FIG. FIG. 3 is an enlarged cross-sectional view of a portion corresponding to a portion X in FIG. 1 showing a second embodiment of the fuel injection valve of the present invention. FIG. 5 is an enlarged cross-sectional view of a portion corresponding to a portion X in FIG. 1 showing a third embodiment of the fuel injection valve of the present invention. FIG. 7 is an enlarged cross-sectional view of a portion corresponding to a portion X in FIG. 1 showing a fourth embodiment of the fuel injection valve of the present invention. It is sectional drawing which shows a division structure in the Example of the cyclic | annular heat resistant protection member 13 in 1st Embodiment of this invention fuel injection valve. It is a decomposition | disassembly upper perspective view of the cyclic | annular heat resistant protection member 13 of the division | segmentation structure shown in FIG. It is sectional drawing which uses for the nozzle part 2 of the cyclic | annular heat-resistant protective member 13 of the division | segmentation structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve 2 Nozzle part 2a The outer peripheral part of the nozzle part 2 2b The annular groove part 2c of the nozzle part 2 2c The front end side step part of the groove part 2b 2d The combustion gas introduction space part of the groove part 2b 2e The rear end side step part of the groove part 2b 4 Needle 5 , 6 Injection hole 7 Retaining nut 8 Internal combustion engine 10 Mounting hole 10a Inner peripheral portion of mounting hole 10 Combustion chamber 12 Annular seal member 12a Exposed portion of annular seal member 12b Tip end surface of annular seal member 12 Annular heat resistance protection Member 13a Exposure protection part 13b of annular heat resistant protective member 13 Position stable holding part 13c of annular heat resistant protective member 13 Convex segment piece constituting annular heat resistant protective member 13d Recessed part constituting annular heat resistant protective member 13 Piece 13e Axial direction dividing surface 13e
13f Axis orthogonal direction division surface 13f
13g Axis parallel direction division surface 13g
A1 Annular exposure area of the exposure protection part 13a of the annular heat resistant protection member 13 A2 Annular exposure area of the exposure part 12a of the annular seal member 12 DI An outer diameter of the exposure protection part 13a of the annular heat resistance protection member 13 D2 Inside the mounting hole 10 Inner diameter F1 of the peripheral portion F1 Combustion gas pressure acting on the exposed area S1 of the convex segment 13c F2 Combustion gas pressure acting on the exposed area S2 of the concave segment 13d L1 Length of the annular heat-resistant protective member 13 in the front-rear direction L2 The length of the annular heat-resistant protective member 13 from the exposed protective part 13a in the annular seal member 12 S1 The exposed area in the convex divided piece 13c S2 The exposed area in the concave divided piece 13d Y The axis of the annular heat-resistant protective member 13

Claims (10)

A fuel injection valve mounted on the internal combustion engine along a mounting hole communicating with a combustion chamber of the internal combustion engine so that a nozzle portion is positioned with a predetermined gap from an inner peripheral portion of the mounting hole,
An annular heat-resistant seal member attached to the outer peripheral portion on the tip end side of the nozzle portion and in contact with the inner peripheral portion of the mounting hole;
An annular heat-resistant protective member having an exposure protection portion that is mounted on the distal end side further than the mounting position of the annular heat-resistant seal member and covers the distal end side surface of the annular heat-resistant seal member ;
The annular heat resistant seal member and the annular heat resistant protective member are made of different materials, and the annular heat resistant protective member is a heat resistant elastic metal member having a higher melting point than the annular heat resistant seal member,
The annular heat-resistant seal member and the annular heat-resistant protective member are mounted in an annular groove formed in the outer peripheral portion on the tip side of the nozzle portion, and the annular heat-resistant seal is provided in the annular heat-resistant seal member and the annular heat-resistant protective member. The rear end side of only the member is in contact with the rear end side step portion of the groove, and the exposure area A1 of the exposure protection portion of the annular heat resistant protection member is set larger than the exposure area A2 of the exposure portion of the annular heat resistant seal member. The fuel injection valve characterized by the above-mentioned . 2. The fuel injection valve according to claim 1, wherein the annular heat resistant seal member has a hardness lower than that of a material of a mounting hole portion of the internal combustion engine . The fuel injection valve according to claim 1 or 2, wherein the annular heat-resistant protective member is made of stainless steel, and the annular heat-resistant sealing member is made of polytetrafluoroethylene material . The fuel injection valve according to any one of claims 1 to 3, wherein the annular heat-resistant protective member is provided with an exposure protection part extending in a radial direction and a position stable holding part extending in the front-rear direction . The fuel injection valve according to claim 4, wherein the position stable holding portion is disposed inside the annular heat resistant seal member. A length L1 of the position stable holding portion from the front end side of the exposure protection portion of the annular heat resistance protection member is set shorter than a length L2 of the annular heat resistance seal member from the front end side of the exposure protection portion of the annular heat resistance protection member. according to claim 4 or 5 fuel injection valve, wherein the being. The annular heat-resistant protective member includes two axially divided surfaces passing through the axis, two axially orthogonally divided surfaces connected to the two axially divided surfaces and orthogonal to the two axially divided surfaces, and the 2 A two-division structure connected to two axis-orthogonal dividing surfaces and divided by two axis-parallel-division surfaces parallel to the two axial-direction dividing surfaces, wherein the two axis-orthogonal dividing surfaces are the two axial directions An exposure area S1 of one divided convex divided piece protruding from the dividing plane is exposed to the other divided concave divided piece in which the two axial orthogonal dividing planes are recessed from the two axial dividing planes. The fuel injection valve according to any one of claims 1 to 6, wherein the fuel injection valve is set to be larger than the area S2 . The fuel injection valve according to any one of claims 1 to 3, wherein the annular heat-resistant protective member includes only an exposure protection portion extending in a radial direction . 9. The fuel injection valve according to claim 8, wherein the annular heat-resistant protective member is sandwiched between the annular heat-resistant sealing member and a front end side step portion of an annular groove portion of the nozzle portion . The fuel according to any one of claims 1 to 9 , wherein an outer diameter length D1 of the exposure protection portion of the annular heat-resistant protective member is set shorter than an inner diameter D2 of the mounting hole of the internal combustion engine. Injection valve.

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