JP2014141914A - Fluid control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid control valve capable of opening and closing by small driving force with a simple construction.SOLUTION: A balance rod 11 provided slidably with a needle 30 forms a low-pressure chamber 27 in communication with a core chamber 34 formed inside a housing 20. A needle chamber 32 capable of communicating with a nozzle 242 is formed between a nozzle part 24 and a valve part 303. The needle chamber 32 communicates with the core chamber 34 via a throttle flow passage 28. When opening of the valve, if balance between acting force acting on the needle 30 in a valve closing direction and acting force acting on the needle 30 in a valve opening direction, which are caused by pressure of fuel, changes as compared with when closing of the valve, the needle chamber 32 and the core chamber 34 exchange fuel via the throttle flow passage 28. With this, the acting force acting on the needle 30 in the valve opening direction and the acting force acting on the needle 30 in the valve closing direction, which are caused by pressure of fuel, can be balanced in the same relationship either when closing of the valve or when opening of the valve.

Description

  The present invention relates to a fluid control valve that controls the flow of fluid.

  Conventionally, a fuel injection valve that opens and closes an injection hole formed in a housing and injects fuel in the housing is known. In the fuel injection valve, the fuel pressure acts on the needle that opens and closes the nozzle hole in both the valve opening direction and the valve closing direction. If the acting force acting in the valve opening direction and the acting force acting in the valve closing direction are balanced in the same relationship both when the valve is opened and when the valve is closed, the opening and closing of the fuel injection valve are reduced in driving force. This can be done easily. For example, Patent Document 1 includes a nozzle needle that can open and close an injection hole and a core needle that reciprocates integrally with the nozzle needle, and the pressure of the fuel acting on the nozzle needle and the core needle is in the valve opening direction and the valve closing direction. Also describes a fuel injection valve that balances.

German Patent Application Publication No. 102010040307

  However, in the fuel injection valve described in Patent Document 1, when the valve is closed, the nozzle needle and the core needle that are slidably supported by the core needle simultaneously abut against the valve seat, so that the configuration of the fuel injection valve is complicated. In addition, high processing accuracy is required during manufacturing.

  An object of the present invention is to provide a fluid control valve that can be opened and closed with a simple structure and a small driving force.

  The present invention includes an inlet for introducing a fluid, a housing for forming a valve seat provided around the outlet and the outlet for discharging the fluid, a coil for generating a magnetic field when energized, and a magnetic field generated by the coil. A fixed core fixed to the fixed core, a movable core provided on the valve seat side of the fixed core and attracted to the fixed core side when the coil generates a magnetic field, and can be reciprocated integrally with the movable core on the valve seat side of the movable core And a valve body that blocks or communicates with the first pressure chamber formed between the inner wall of the housing and the lead-out port when contacting or separating from the valve seat, and is slidably provided on the housing or the movable core. A balance rod that forms a third pressure chamber that communicates with the second pressure chamber communicating with the introduction port and the outside between the housing and the movable core, and a biasing means that biases the valve body in the direction of the valve seat; A fluid control valve with In the valve body, when the valve body and the valve seat come into contact with each other, the cross-sectional area of the fourth pressure chamber formed between the outer wall of the valve body and the valve seat is cut off at the part where the cross section of the fourth pressure chamber slides with the inner wall of the housing of the movable core. The second pressure chamber and the first pressure chamber, which are formed to be smaller than the area and accommodate the movable core, are characterized in that they communicate with each other through a throttle channel.

In the fluid control valve of the present invention, the fluid introduced from the inlet is led out from the outlet through the second pressure chamber, the throttle channel, and the first pressure chamber. The pressure of the fluid in the first pressure chamber acts to move the valve body in the valve opening direction. Moreover, the pressure of the fluid in the second pressure chamber acts to move the movable core in the valve closing direction.
When the valve is closed, the acting force in the valve opening direction and the acting force in the valve closing direction acting on the movable core and the valve body are large and small between the cross-sectional area of the balance rod forming the third pressure chamber and the cross-sectional area of the fourth pressure chamber. Based on the relationship, a balance is established in a predetermined relationship. On the other hand, when the valve body is separated from the valve seat when the valve is opened, the fluid in the first pressure chamber flows into the fourth pressure chamber. At this time, since the area where the fuel pressure of the first pressure chamber acts increases, the acting force in the valve opening direction acting on the valve element becomes larger than when the valve is closed, but the first pressure chamber is connected to the first pressure chamber via the throttle channel. Fluid is appropriately exchanged with the second pressure chamber, and the acting force in the valve opening direction and the acting force in the valve closing direction are adjusted so as to balance in the predetermined relationship. As a result, the “balance” between the acting force in the valve closing direction and the acting force in the valve opening direction due to the fluid pressure has the same relationship both when the valve is opened and when the valve is closed. Therefore, the driving force for driving the movable core and the valve body when the valve is opened or closed can be reduced with a simple configuration.

  Moreover, since it is a simple structure, a high processing precision is not required at the time of manufacture of the components which constitute the fluid control valve. Thereby, the fluid control valve of this invention can implement | achieve the structure of a balance valve, without requiring high processing precision.

It is sectional drawing of the fuel injection valve by 1st Embodiment of this invention. It is a characteristic view which shows the 1st experimental result in the fuel injection valve by 1st Embodiment of this invention. It is a characteristic view which shows the 2nd experiment result in the fuel injection valve by 1st Embodiment of this invention. It is sectional drawing of the fuel injection valve by 2nd Embodiment of this invention. It is sectional drawing of the fuel injection valve by 3rd Embodiment of this invention. It is sectional drawing of the fuel injection valve by 4th Embodiment of this invention. It is sectional drawing of the fuel injection valve by 5th Embodiment of this invention. It is sectional drawing of the fuel injection valve by 6th Embodiment of this invention. It is sectional drawing of the fuel injection valve by 7th Embodiment of this invention.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A fuel injection valve according to a first embodiment of the present invention is shown in FIG. FIG. 1 illustrates a valve opening direction in which the needle 30 is separated from the valve seat 26 and a valve closing direction in which the needle 30 is in contact with the valve seat 26.

  The fuel injection valve 1 is used, for example, in a fuel injection device of a direct injection gasoline engine (not shown), and injects and supplies gasoline as fuel to the engine. The fuel injection valve 1 includes a housing 20, a needle 30, a fixed core 35, a coil 36, and the like.

  The housing 20 includes a first cylinder member 21, a second cylinder member 22, a third cylinder member 23, a nozzle member 24, and a lid member 25.

The 1st cylinder member 21 and the 3rd cylinder member 23 are formed, for example from magnetic materials, such as ferritic stainless steel, and the magnetic stabilization process is performed. On the other hand, the 2nd cylinder member 22 is formed from nonmagnetic materials, such as austenitic stainless steel, for example. The first cylinder member 21, the second cylinder member 22, and the third cylinder member 23 are all formed in a substantially cylindrical shape, and are coaxial in the order of the first cylinder member 21, the second cylinder member 22, and the third cylinder member 23. Are arranged and connected to each other.
An introduction port 211 is formed on the radially outer side of the first cylinder member 21. The inlet 211 is connected to a fuel tank (not shown) and introduces fuel in the fuel tank into the housing 20.

The nozzle member 24 is formed in a bottomed cylindrical shape. The nozzle member 24 is connected to the end of the third cylinder member 23 opposite to the end connected to the second cylinder member 22 by welding. A concave portion 241 into which a part of the needle 30 is inserted is formed in the axial direction of the nozzle member 24. A plurality of injection holes 242 serving as “outlet ports” for communicating the inside and the outside of the housing 20 are formed at the end of the nozzle member 24 opposite to the end connected to the third cylinder member 23. A valve seat 26 is formed at the edge of the opening on the concave portion 241 side of the nozzle hole 242.
In addition, the nozzle member 24 forms a throttle channel 28 that communicates a needle chamber 32 and a core chamber 34 described later. The throttle channel 28 is, for example, an orifice that reduces the cross-sectional area of the channel.

  The lid member 25 is provided at the end of the first cylinder member 21 opposite to the end connected to the second cylinder member 22. The lid member 25 includes a large diameter part 251, a medium diameter part 252, the balance rod 11, and the like. The large diameter part 251, the medium diameter part 252, and the balance rod 11 are integrally formed.

  The large-diameter portion 251 is a substantially cylindrical portion that fits into an opening formed at an end portion on the opposite side of the end portion of the first tubular member 21 that is connected to the second tubular member 22. The large-diameter portion 251 holds the liquid tightness between the inside and the outside of the housing 20 while fixing the lid member 25 to the first cylinder member 21.

  The medium diameter portion 252 is a substantially cylindrical portion provided on the inner side of the housing 20 of the large diameter portion 251. The medium diameter part 252 is formed so that the outer diameter is smaller than that of the large diameter part 251. The medium diameter part 252 forms a fuel passage 254 between the inner diameter part 252 and the inner wall of the first cylinder member 21. The fuel passage 254 communicates with the introduction port 211.

  The balance rod 11 is a cylindrical portion formed so as to extend from the medium diameter portion 252 toward the valve seat 26. The balance rod 11 is inserted into the fixed core 35, and the end 111 on the valve seat 26 side of the balance rod 11 is slidably inserted into the recess 31 formed in the needle 30.

  The lid member 25 has a communication path 256 formed in the axial direction. The communication path 256 includes a low pressure chamber 27 formed between the inner wall 310 of the small inner diameter portion 312 of the recess 31 formed in the needle 30 and the outer wall of the end portion 111 of the balance rod 11, and the outside of the fuel injection valve 1. And communicate with each other. In the fuel injection valve 1 according to the first embodiment, the communication passage 256 is connected to a return pipe (not shown) that returns the fuel in the low pressure chamber 27 to the fuel tank. At this time, the balance rod 11 forming the low-pressure chamber 27 is formed to have a diameter of R1.

  The needle 30 is accommodated in the housing 20 so as to be reciprocally movable. The needle 30 includes a core part 301, a shaft part 302, and a valve part 303. The core part 301, the shaft part 302, and the valve part 303 are integrally formed. When the needle 30 is separated from the valve seat 26 or abuts against the valve seat 26, the nozzle hole 242 is opened and closed.

  The core portion 301 is formed from a cylindrical magnetic material and is provided on the fixed core 35 side of the needle 30. The core portion 301 is accommodated in a core chamber 34 formed between the inner wall 201 as the “second inner wall” of the housing 20 and the fixed core 35 so as to be reciprocally movable.

  The shaft portion 302 is formed in a bottomed cylindrical shape, and is provided on the valve seat 26 side of the core portion 301. The shaft portion 302 is formed so that the outer diameter is smaller than the outer diameter of the core portion 301. The outer wall 304 on the radially outer side of the shaft portion 302 slides with the inner wall 243 as the “third inner wall” of the recess 241 of the nozzle member 24. The shaft portion 302 corresponds to “a portion that slides with the inner wall of the housing of the movable core” recited in the claims.

  The valve portion 303 is formed of a substantially rod-like material having high hardness, and is provided on the valve seat 26 side of the shaft portion 302. The valve portion 303 as a “valve element” is accommodated in the concave portion 241 of the nozzle member 24 so as to be able to reciprocate. The valve portion 303 is formed so that the seal diameter when the valve portion 303 abuts on the valve seat 26 is R2 having the same size as the diameter R1 of the balance rod 11 of the lid member 25.

  Among the inner walls forming the recess 241 of the nozzle member 24, there is a “first pressure chamber” between an inner wall 244 as a “first inner wall” radially outside the valve seat 26 and an outer wall 305 radially outside the valve portion 303. As a needle chamber 32 is formed. Further, a sack 33 as a “fourth pressure chamber” is formed between the valve seat 26 and the outer wall 306 in the reciprocating direction of the valve portion 303 in the inner wall forming the concave portion 241 of the nozzle member 24. The outer wall 306 corresponds to “an outer wall surface in the reciprocating direction of the valve body” recited in the claims.

The core portion 301 and the shaft portion 302 are formed with recesses 31 in the axial direction. The recess 31 includes a core portion 301 and a large inner diameter portion 311 formed on a part of the shaft portion 302 on the core portion 301 side, and a small inner diameter portion 312 formed on the shaft portion 302. The balance rod 11 of the lid member 25 is inserted into the recess 31.
The large inner diameter portion 311 forms a through hole, and a relatively large gap is formed between the inner wall and the outer wall of the balance rod 11. The small inner diameter portion 312 is formed in a bottomed cylindrical shape so that the inner diameter is smaller than the inner diameter of the large inner diameter portion 311. The radially inner wall of the small inner diameter portion 312 slides with the radially outer wall of the balance rod 11.
The shaft portion 302 is also formed with a communication passage 307 that connects the inner wall of the recess 31 and the outer wall of the shaft portion 302.

  The fixed core 35 is formed in a substantially cylindrical shape from a magnetic material and is subjected to a magnetic stabilization process. The fixed core 35 is fixed to the inside of the housing 20 via a disc spring 351 provided on an end surface of the lid member 25 on the valve seat 26 side while abutting the second cylindrical member 22 of the housing 20. ing. A through hole 352 into which the balance rod 11 of the lid member 25 is inserted is formed in the axial direction of the fixed core 35. The through hole 352 communicates the fuel passage 254 and the core chamber 34.

  The coil 36 is formed in a substantially cylindrical shape, and is provided on the outer side of the housing 20, particularly, in the radial direction of the second cylindrical member 22. The coil 36 generates a magnetic force when electric power is supplied. When the coil 36 generates magnetic force, a magnetic circuit is formed that passes through the fixed core 35, the core portion 301 of the needle 30, the third cylinder member 23, and the first cylinder member 21. As a result, a magnetic attractive force is generated between the fixed core 35 and the core portion 301 of the needle 30, and the needle 30 is attracted to the fixed core 35.

  One end of the spring 37 abuts on a step surface 353 formed on the fixed core 35. The other end is in contact with the end surface of the needle 30 on the fixed core 35 side. The spring 37 as “first urging means” urges the needle 30 in a direction away from the fixed core 35, that is, in a direction in which the needle 30 contacts the valve seat 26.

  Next, the operation of the fuel injection valve 1 will be described.

  When power is not supplied to the coil 36, the valve portion 303 of the needle 40 is brought into contact with the valve seat 26 by the urging force of the spring 37, that is, the valve is closed. The fuel that flows into the housing 20 from the introduction port 211 flows into the needle chamber 32 through the fuel passage 254, the through hole 352, the core chamber 34, and the throttle channel 28. At this time, since the sac 33 is in contact with the valve portion 303 and the valve seat 26, the fuel in the needle chamber 32 does not flow into the sack 33. As a result, the pressure of the fuel in the sac 33 is relatively low compared to the pressure of the fuel in the needle chamber 32.

  A part of the fuel in the core chamber 34 leaks into the low pressure chamber 27 through a gap between the inner wall in the radial direction of the small inner diameter portion 312 and the outer wall on the outer side in the radial direction of the balance rod 11. The pressure of the fuel leaking into the low pressure chamber 27 is approximately the same as the pressure outside the fuel injection valve 1.

  When the fuel injection valve 1 is closed, the acting force F1 acting on the needle 30 by the fuel pressure in the valve closing direction is a value obtained by subtracting the cross-sectional area of the low-pressure chamber 27 from the cross-sectional area of the shaft portion 302 of the needle 30. The value is obtained by multiplying the fuel pressure of 34. On the other hand, the acting force F2 in the valve opening direction acting on the needle 30 by the fuel pressure is obtained by multiplying the value of the fuel in the needle chamber 32 by the value obtained by subtracting the cross-sectional area of the sack 33 from the cross-sectional area of the shaft 302 of the needle 30. Value. Since the diameter R1 of the end 111 of the balance rod 11 and the seal diameter R2 of the sack 33 are the same size, the cross-sectional area of the low-pressure chamber 27 and the cross-sectional area of the sack 33 are the same size. Further, when the valve is closed, the pressure of the fuel in the core chamber 34 and the needle chamber 32 is the same, so the acting force F1 and the acting force F2 have the same magnitude. Thereby, the fuel injection valve 1 balances the acting force in the valve opening direction and the acting force in the valve closing direction with the same magnitude due to the fuel pressure.

  When power is supplied to the coil 36, a magnetic attractive force is generated between the fixed core 35 and the core portion 301 of the needle 30. The needle 30 is attracted to the fixed core 35 by the generated magnetic attraction force. The needle 30 is separated from the valve seat 26, and the fuel in the needle chamber 32 is injected to the outside of the fuel injection valve 1 through the plurality of injection holes 242. At this time, the sac 33 is filled with fuel in the needle chamber 32.

  When the fuel injection valve 1 is opened, the closing force F3 acting on the needle 30 due to the fuel pressure is a value obtained by subtracting the cross-sectional area of the low-pressure chamber 27 from the cross-sectional area of the shaft portion 302 of the needle 30. The value obtained by multiplying the pressure of the fuel in the core chamber 34 by the value is not changed compared to when the valve is closed. On the other hand, the acting force F4 in the valve opening direction that acts on the needle 30 due to the pressure of the fuel flows into the cross-sectional area of the shaft portion 302 of the needle 30 because the fuel in the needle chamber 32 flows into the sack 33. It becomes the value which multiplied the pressure of and becomes large compared with the time of valve closing. In the fuel injection valve 1 according to the first embodiment, fuel is exchanged between the core chamber 34 and the needle chamber 32 via the throttle channel 28 by appropriately setting the cross-sectional area of the throttle channel 28, and the core chamber. 34 and the pressure of the fuel in the needle chamber 32 are adjusted so that the acting force F3 and the acting force F4 have the same magnitude both when the valve is closed and when the valve is opened.

  Here, the experimental result of FIG. 2 and FIG. 3 is demonstrated about the characteristic of the fuel injection valve 1 by 1st Embodiment.

  FIG. 2 shows, as a first experimental result, a characteristic diagram showing a change over time of the characteristic of the fuel injection valve 1 when the diameter of the throttle channel 28 is changed. FIG. 2A is a characteristic diagram illustrating a change over time in the needle lift amount of the needle 30. FIG. 2B is a characteristic diagram showing a time change of the magnetic attractive force generated between the core portion 301 of the needle 30 and the fixed core 35. FIG. 2C is a characteristic diagram showing time differentiation of the injection amount of the fuel injection valve 1, that is, time variation of the injection rate. In FIG. 2, the experimental result when the diameter of the throttle channel 28 is 1.0 mm is indicated by a solid line L1, the experimental result when the diameter is 0.9 mm is indicated by a one-dot chain line L2, and the experimental result when the diameter is 0.83 mm is indicated by a dotted line. The experimental result when the diameter is L3 and the diameter is 0.76 mm is indicated by a two-point difference line L4.

From the time change of the needle lift amount shown in FIG. 2A, it becomes clear that the needle lift amount stably changes from the valve opening to the valve closing when the diameter is 0.9 mm and 0.83 mm. It was.
On the other hand, when the diameter is 0.76 mm, as shown in FIG. 2A, after the needle lift amount is once increased, the fuel pressure in the core chamber 34 and the fuel pressure in the needle chamber 32 and the sac 33 are It became clear that the needle lift amount is not stable, for example, the needle lift amount becomes 0 or becomes larger due to the relationship. For this reason, when a throttle channel having a diameter of 0.76 mm was used, it became clear that neither the magnetic attractive force shown in FIG. 2 (b) nor the injection rate shown in FIG. 2 (c) was stable. . From this, it became clear that when the diameter of the throttle channel 28 is small, it is difficult to maintain a stable valve opening state.

When the diameter is 1.0 mm, as shown in FIG. 2A, the needle lift amount is a magnetic attraction force due to the relationship between the fuel pressure in the core chamber 34 and the fuel pressure in the needle chamber 32 and the sac 33. It became constant regardless of the size, and as shown in FIG. 2 (c), it became clear that the injection rate was not 0, that is, the valve could not be closed.
Further, when the case where the diameter is 0.9 mm and the case where the diameter is 0.83 mm are compared, it has been clarified that the valve having a smaller diameter closes earlier as shown in FIG.

FIG. 3 is a characteristic diagram showing the relationship between the cross-sectional area of the throttle channel 28 and the fuel pressure in the needle chamber 32 as a second experimental result. FIG. 3 shows a cross-sectional area of the throttle channel 28 that can open and close the fuel injection valve 1 when the pressure of the fuel in the core chamber 34 is 120 MPa. As shown in FIG. 3, when the diameter of the throttle channel 28 is 0.94 mm, it is in the vicinity of the valve closing limit, and the fuel injection valve 1 can be opened and closed by forming the throttle channel 28 having a smaller diameter. At this time, the pressure of the fuel in the needle chamber 32 is 113.8 MPa, which is 95% of the pressure of the fuel in the core chamber 34. On the other hand, when the diameter of the throttle channel 28 is 0.83 mm, it is in the vicinity of the valve closing holdable limit, and the fuel injector 1 can be opened and closed by forming the throttle channel 28 having a larger diameter. At this time, the pressure of the fuel in the needle chamber 34 is 109.2 MPa, which is 91% of the pressure of the fuel in the core chamber 34. That is, when the pressure of the fuel in the core chamber 32 is 120 MPa, the sectional area of the throttle channel 28 that can open and close the fuel injection valve 1 is clearly 0.54 mm ² or more and 0.69 mm ² or less. It was.

ここで、軸部３０２の断面積Ａ２は、バランスロッド１１の直径Ｒ１を用いると、Ａ２＝π×（Ｒ１／２）²と表すことができる。また、サック３３の断面積Ａ３は、弁部３０３が弁座２６に当接するときのシール径Ｒ２を用いると、Ａ３＝π×（Ｒ２／２）²と表すことができる。また、噴孔２４２の断面積Ａ４は、複数ある噴孔２４２の断面積の合計である。 In the fuel injection valve 1 according to the first embodiment, the cross-sectional area of the narrowest portion of the throttle channel 28 is A0 (m ² ), the cross-sectional area of the injection hole 242 is A4 (m ² ), and the cross-sectional area of the shaft portion 302 is A2. When (m ² ) and the cross-sectional area of the sack 33 are A3 (m ² ), an appropriate cross-sectional area of the throttle channel 28 is expressed by the following formula 1.

Here, the cross-sectional area A2 of the shaft portion 302 can be expressed as A2 = π × (R1 / 2) ² when the diameter R1 of the balance rod 11 is used. Further, the cross-sectional area A3 of the sack 33 can be expressed as A3 = π × (R2 / 2) ² when the seal diameter R2 when the valve portion 303 is in contact with the valve seat 26 is used. The cross-sectional area A4 of the nozzle hole 242 is the sum of the cross-sectional areas of the plurality of nozzle holes 242.

  As described above, in the fuel injection valve 1 according to the first embodiment, the throttle passage 28 having an appropriate cross-sectional area is formed, so that the valve opening caused by the fuel pressure is generated both when the valve is closed and when the valve is opened. The acting force in the direction and the acting force in the valve closing direction are balanced with the same magnitude. This realizes a “balance valve” that balances the acting force in the valve opening direction and the acting force in the valve closing direction with the same relationship both when the valve is closed and when the valve is opened, with a simple configuration. Can do. Therefore, the valve can be easily opened and closed with a small driving force.

  Further, by forming the throttle channel 28 having an appropriate cross-sectional area, even when the pressure of the fuel introduced from the introduction port 211 is set high, the acting force in the valve opening direction and the acting force in the valve closing direction due to the fuel pressure are set. Are exchanged between the core chamber 34 and the needle chamber 32 via the throttle channel 28 so as to balance them in the same size. Thereby, it can be easily opened and closed with a small driving force regardless of the pressure of the fuel.

(Second Embodiment)
Next, the fuel injection valve by 2nd Embodiment of this invention is demonstrated based on FIG. The second embodiment differs from the first embodiment in the position where the low pressure chamber is formed. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st Embodiment, and description is abbreviate | omitted.

  In the fuel injection valve 2 according to the second embodiment, the balance rod 12 is provided on the fixed core 35 side of the core portion 301 of the needle 30. The balance rod 12 is inserted through the through hole 352 of the fixed core 35. Further, the end 121 of the balance rod 12 opposite to the end connected to the core 301 is slidably inserted into a recess 257 formed in the medium diameter portion 252 of the lid member 25. .

  The low pressure chamber 27 formed between the inner wall 258 of the recess 257 and the end 121 of the balance rod 12 communicates with the outside of the fuel injection valve 2 via the communication path 256. The balance rod 12 is formed so that its diameter R3 is the same as the seal diameter R2 between the valve portion 303 and the valve seat 26.

  In the fuel injection valve 2 according to the second embodiment, the core chamber 34 and the needle chamber 32 communicate with each other through the throttle channel 28. The fuel injection valve 2 forms the throttle passage 28 having an appropriate cross-sectional area, so that the acting force in the valve opening direction and the acting force in the valve closing direction are the same when the valve is opened and closed. It works to balance with. Therefore, the fuel injection valve 2 according to the second embodiment has the same effects as the first embodiment.

(Third embodiment)
Next, a fuel injection valve according to a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the second embodiment in that the balance rod and the needle are formed separately. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 2nd Embodiment, and description is abbreviate | omitted.

  In the fuel injection valve 3 according to the third embodiment, the needle 40 and the balance rod 13 are provided separately. The needle 40 includes a core part 401, a concave part 402, a shaft part 403, and a valve part 404.

The core portion 401 is formed in a cylindrical shape and is provided on the fixed core 35 side of the needle 40. The other end of the spring 37 that urges the needle portion 40 in the direction separating the needle 40 from the fixed core 35, that is, the direction in which the needle 40 contacts the valve seat 26, is in contact with the end surface of the core portion 401 on the fixed core 35 side.
The concave portion 402 is provided between the core portion 401 and the shaft portion 403. The balance rod 13 is inserted into the through hole 406 of the core portion 401, and the end portion 132 is accommodated in the recess 402. The core part 401 and the recessed part 402 are corresponded to the "movable core" as described in a claim.

  The shaft portion 403 is provided on the valve seat 26 side of the recess 402. The shaft part 403 is formed so that the outer diameter is smaller than the outer diameters of the core part 401 and the recessed part 402. The outer wall 407 on the radially outer side of the shaft portion 403 slides with the inner wall 243 of the recess 241 formed in the nozzle member 24. The shaft portion 403 corresponds to a “movable core” recited in the claims.

  The valve portion 404 is formed of a substantially rod-like material having high hardness, and is accommodated in the concave portion 241 of the nozzle member 24 so as to be reciprocally movable. The valve portion 404 as the “valve element” is such that when the valve portion 404 abuts on the valve seat 26, the seal diameter between the valve portion 404 and the valve seat 26 becomes R5 having the same size as the diameter R4 of the balance rod 13. Is formed.

  In the fuel injection valve 3 according to the third embodiment, the core chamber 34 and the needle chamber 32 communicate with each other through the throttle channel 28. As a result, the fuel injection valve 3 forms the throttle passage 28 having an appropriate cross-sectional area so that the opening force and the closing force due to the fuel pressure can be reduced when the valve is opened and closed. Functions to balance at the same size. Therefore, the fuel injection valve 3 according to the third embodiment has the same effect as the second embodiment.

  In the fuel injection valve 3, the balance rod 13 and the needle 40 are provided separately. Thereby, since the coaxial process of the balance rod 13 and the needle 40 is not required, the balance rod 13 and the needle 40 can be processed easily.

  Further, since the balance rod 13 and the needle 40 are provided separately, a certain amount of axial deviation of the balance rod 13 with respect to the needle 40 can be allowed.

(Fourth embodiment)
Next, the fuel injection valve by 4th Embodiment of this invention is demonstrated based on FIG. The fourth embodiment differs from the first embodiment in the shape of the nozzle member. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st Embodiment, and description is abbreviate | omitted.

  In the fuel injection valve 4 according to the fourth embodiment, the nozzle member 44 is formed in a bottomed cylindrical shape. A concave portion 441 into which a part of the needle 30 is inserted is formed in the axial direction of the nozzle member 44. The inner wall 443 of the concave portion 441 of the nozzle member 44 and the outer wall 304 of the shaft portion 302 of the needle 30 facing the inner wall 443 do not slide, and a gap 444 as a “throttle channel” is formed.

  A plurality of injection holes 442 serving as “outlet ports” for communicating the inside and the outside of the housing 20 are formed at the end of the nozzle member 44 opposite to the side connected to the third cylinder member 23. A valve seat 26 is formed at the edge of the opening on the concave portion 441 side of the injection hole 442.

  In the fuel injection valve 4, the fuel that flows into the housing 20 from the introduction port 211 flows into the needle chamber 32 through the fuel passage 254, the through hole 352, the core chamber 34, and the gap 444.

  In the fuel injection valve 4 according to the fourth embodiment, the core chamber 34 and the needle chamber 32 communicate with each other through a gap 444. As a result, the fuel injection valve 4 forms a gap 444 having an appropriate cross-sectional area so that the opening force and the closing force due to the fuel pressure are the same when opening and closing. It works to balance. Therefore, the fuel injection valve 4 according to the fourth embodiment has the same effects as the first embodiment.

(Fifth embodiment)
Next, a fuel injection valve according to a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment differs from the first embodiment in the shapes of the housing and the needle. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st Embodiment, and description is abbreviate | omitted.

  The fuel injection valve 5 according to the fifth embodiment includes a housing 50, a balance rod 15, a needle 60, a fixed core 65, a coil 66, and the like.

  The housing 50 includes a first housing member 51, a second housing member 52, and a nozzle member 24. The first housing member 51, the second housing member 52, and the nozzle member 24 are connected by, for example, welding.

  The first housing member 51 is formed in a substantially cylindrical shape. The first housing 51 is connected to a second housing member 52 provided on the radially outer side of the first housing 51, thereby forming a recess 501 that accommodates the fixed core 65, the coil 66, the balance rod 15, and the like. An introduction port 511 is formed at one end of the first housing member 51. The introduction port 511 communicates with a fuel passage 512 as a “second pressure chamber” formed in the axial direction of the first housing member 51. The introduction port 511 communicates with a fuel tank (not shown).

  The second housing member 52 forms a communication passage 521 that connects the recess 501 and the outside of the fuel injection valve 5 in a part of the outer side of the housing 50 in the radial direction. In the fuel injection valve 5 according to the fifth embodiment, the communication passage 521 is connected to a return pipe (not shown) that returns the fuel in the recess 501 to the fuel tank.

  The balance rod 15 is a cylindrical member that is slidably accommodated in the fixed core 65. The end 151 on the introduction port 511 side of the balance rod 15 is in contact with one end of a spring 67 as “third urging means” for urging the balance rod 15 toward the valve seat 56. The end 152 of the balance rod 15 on the valve seat 56 side is formed in a substantially truncated cone shape, and the tip of the end 152 is in contact with the end surface 600 of the needle 60 on the fixed core 65 side. A through hole 153 formed in the axial direction of the balance rod 15 communicates with the fuel passage 512 of the first housing member 51.

  The needle 60 is made of a magnetic material and is accommodated in the housing 50 so as to be reciprocally movable. The needle 60 includes a core part 601, a shaft part 602, and a valve part 603.

  The core part 601 is accommodated in a core chamber 64 formed between the inner wall of the housing 50 and the fixed core 65 so as to be reciprocally movable. The fuel leaking from between the outer wall of the balance rod 15 and the through hole 652 of the fixed core 65 flows into the core chamber 64. The fuel in the core chamber 64 having a relatively low pressure compared to the fuel flowing through the fuel passage 512 is discharged to the outside of the fuel injection valve 5 through the communication passage 521. In the fuel injection valve 5 according to the fifth embodiment, the communication passage 521 is connected to a return pipe (not shown) that returns the fuel in the core chamber 64 to the fuel tank.

  The shaft portion 602 is formed so that its outer diameter is smaller than the outer diameter of the core portion 601. The outer wall 604 on the outer side in the radial direction of the shaft portion 602 slides with the inner wall 243 of the recess 241 of the nozzle member 24. The shaft portion 602 corresponds to “a portion that slides with the inner wall of the housing of the movable core” recited in the claims.

  The valve portion 603 is formed so that its outer diameter is smaller than the outer diameter of the shaft portion 602. The valve portion 603 connected to the valve seat 56 side of the shaft portion 602 is accommodated in the recessed portion 241 of the nozzle member 24 so as to be able to reciprocate. The end of the valve portion 603 opposite to the end connected to the shaft portion 602 abuts or separates from the valve seat 56.

  A needle chamber 62 as a “first pressure chamber” is formed between the inner wall 244 radially outside the valve seat 56 and the outer wall 605 radially outer of the valve portion 603 among the inner walls forming the recess 241 of the nozzle member 24. It is formed. Further, a sack 63 as a “fourth pressure chamber” is formed between the valve seat 56 and the axial outer wall 606 of the valve portion 603 in the inner wall forming the recess 241 of the nozzle member 24.

  The needle 60 forms a communication path 607 substantially parallel to the axial direction of the needle 60. The communication path 607 communicates with a throttle channel 68 formed substantially perpendicular to the axial direction of the needle 60. As a result, the fuel that flows into the housing 50 from the introduction port 511 flows into the needle chamber 62 via the fuel passage 512, the through hole 153 of the balance rod 15, the communication passage 607, and the throttle passage 68.

  The fixed core 65 is formed in a substantially cylindrical shape from a magnetic material, and is subjected to a magnetic stabilization process. A through hole 652 is formed in the axial direction of the fixed core 65. The balance rod 15 is slidably accommodated in the through hole 652.

  The coil 66 is formed in a substantially cylindrical shape and is provided inside the fixed core 65. A magnetic attraction force is generated between the fixed core 65 and the needle 60 due to the magnetic force generated when electric power is supplied to the coil 66, and the needle 60 is attracted to the fixed core 65.

When the diameter of the balance rod 15 is R6, the diameter of the shaft portion 602 is R7, and the seal diameter between the valve portion 603 and the valve seat 56 is R8 when the valve portion 603 contacts the valve seat 56, the fuel injection valve 5 is as follows. It is formed so that the following formula 2 may be satisfied.
R6 ² = R7 ² −R8 ² ... Formula 2
Thereby, the fuel injection valve 5 functions as a “balance valve” that balances the acting force in the valve opening direction and the acting force in the valve closing direction with the same magnitude when the valve is closed. π × (R6 / 2) ² corresponds to “A1” recited in the claims. π × (R7 / 2) ² corresponds to “A2” recited in the claims. π × (R8 / 2) ² corresponds to “A3” recited in the claims.

  Further, when the fuel injection valve 5 is opened, the acting force in the valve opening direction becomes larger than the acting force in the valve closing direction due to the fuel flowing into the sack 63. However, by setting the cross-sectional area of the throttle channel 68 to an appropriate size, the balance between the force acting in the valve opening direction and the force acting in the valve closing direction acting on the balance rod 17 and the needle 60 is the same as when the valve is closed. Fuel is exchanged between the fuel passage 512 and the needle chamber 62 so that Accordingly, the fuel injection valve 5 is configured so that the acting force in the valve opening direction due to the pressure of the fuel such as the fuel passage 512 and the acting force in the valve closing direction due to the pressure of the fuel such as the needle chamber 62 are balanced with the same magnitude. To work. Therefore, the fuel injection valve 5 according to the fifth embodiment has the same effects as the first embodiment.

  In the fuel injection valve 5, the fuel pressure in the fuel passage 512 acts on the balance rod 15 in the direction of the needle 60, so that fuel leaks between the end portion 152 of the balance rod 15 and the end surface 600 of the needle 60. No gap is formed. The fuel introduced into the housing 50 from the introduction port 511 flows into the needle chamber 62 without flowing into the core chamber 64 having a relatively large cross-sectional area. Thereby, the pressure receiving area where the high-pressure fuel acts in the fuel injection valve 5 can be reduced. Therefore, the structure of the housing 50 can be simplified.

  In the fuel injection valve 5, the balance rod 15 and the needle 60 are provided separately. Thereby, since the coaxial process of the balance rod 15 and the needle 60 is not required, the balance rod 13 and the needle 40 can be processed easily.

(Sixth embodiment)
Next, a fuel injection valve according to a sixth embodiment of the present invention will be described with reference to FIG. Unlike the fifth embodiment, the sixth embodiment differs in the position of the throttle channel. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 5th Embodiment, and description is abbreviate | omitted.

  In the fuel injection valve 6 according to the sixth embodiment, a throttle 164 is formed on the inner wall of the through hole 163 formed in the balance rod 16. The fuel introduced from the introduction port 511 flows into the needle chamber 62 through the fuel passage 512, the through hole 163, the communication passage 607, and the communication passage 608 formed substantially perpendicular to the axial direction of the needle 60.

  When the fuel injection valve 6 is opened, the acting force in the valve opening direction becomes larger than the acting force in the valve closing direction due to the fuel flowing into the sack 63. However, by setting the cross-sectional area of the throttle 164 to an appropriate size, the balance between the force acting in the valve opening direction and the force acting in the valve closing direction acting on the balance rod 16 and the needle 60 becomes the same as when the valve is closed. Thus, the fuel is exchanged between the fuel passage 512 and the needle chamber 62. Thus, the fuel injection valve 6 is configured so that the acting force in the valve opening direction due to the pressure of the fuel such as the fuel passage 512 and the acting force in the valve closing direction due to the pressure of the fuel such as the needle chamber 62 are balanced with the same magnitude. To work. Therefore, the fuel injection valve 6 according to the sixth embodiment has the same effects as the fifth embodiment.

(Seventh embodiment)
Next, the fuel injection valve by 7th Embodiment of this invention is demonstrated based on FIG. The seventh embodiment differs from the sixth embodiment in that a member different from the balance rod is provided between the balance rod and the needle. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 6th Embodiment, and description is abbreviate | omitted.

  In the fuel injection valve 7 according to the seventh embodiment, a shake absorbing member 70 is provided between the balance rod 17 and the needle 60.

  The shake absorbing member 70 is formed in a substantially annular shape. As shown in FIG. 9, the shake absorbing member 70 is formed so that the thickness decreases as the distance from the central axis of the shake absorbing member 70 increases. That is, the end surface 701 on the balance rod 17 side of the vibration absorbing member 70 is formed in a curved shape so as to approach the needle 60 as it is away from the central axis of the vibration absorbing member 70, and the end surface 702 on the needle 60 side of the vibration absorbing member 70 is The curved surface is formed so as to approach the balance rod 17 as the distance from the central axis of the vibration absorbing member 70 increases. In the axial direction of the vibration absorbing member 70, an end surface 701 and a through hole 703 connected to the end surface 702 are formed. A diaphragm 704 is formed on the inner wall forming the through hole 703. Note that the end surface 702 on the needle 60 side of the shake absorbing material 70 may be formed in a tapered shape so as to approach the balance rod 17 as the distance from the central axis of the shake absorbing member 70 increases.

  The balance rod 17 applies the urging force of the spring 67 to the needle 60 via the vibration absorbing member 70. The end portion 172 of the balance rod 17 on the needle 60 side is formed in a taper shape so as to approach the needle 60 as it moves away from the central axis of the balance rod 17 so as to contact the end surface 701 of the vibration absorbing member 70.

  The fuel introduced from the introduction port 511 flows into the needle chamber 62 through the fuel passage 512, the through hole 173 formed in the balance rod 17, the through hole 703 of the shake absorbing member 70, and the communication passages 607 and 608.

  When the fuel injection valve 7 is opened, the acting force in the valve opening direction becomes larger than the acting force in the valve closing direction due to the fuel flowing into the sack 63. However, by setting the cross-sectional area of the throttle 704 to an appropriate size, the balance between the force acting in the valve opening direction and the force acting in the valve closing direction acting on the balance rod 17 and the needle 60 becomes the same as when the valve is closed. Thus, the fuel is exchanged between the fuel passage 512 and the needle chamber 62. Thus, the fuel injection valve 7 is configured so that the acting force in the valve opening direction due to the pressure of the fuel such as the fuel passage 512 and the acting force in the valve closing direction due to the pressure of the fuel such as the needle chamber 62 are balanced with the same magnitude. To work. Therefore, the fuel injection valve 7 according to the seventh embodiment has the same effects as the first embodiment.

  Further, the balance rod 17 is in contact with the needle 60 via the shake absorbing member 70. Accordingly, when the position of the balance rod 17 with respect to the needle 60 is shifted, no gap is formed between the balance rod 17 and the vibration absorbing member 70 and between the vibration absorbing member 70 and the needle 60, so that the fuel flowing through the through holes 173 and 607 Can be prevented from leaking into the core chamber 64.

(Other embodiments)
(A) Although the fuel injection valve has been described in the above embodiment, the present invention is not limited to this. This is a fluid control valve that functions to balance the acting force in the valve opening direction and the acting force in the valve closing direction due to the fluid pressure in the same relationship both when the valve is closed and when the valve is opened, and controls the flow of fluid. I just need it.

  (A) In the first to fourth embodiments described above, the seal diameter between the valve portion and the valve seat with respect to the diameter of the low pressure chamber is the same. However, the relationship between the diameter of the low pressure chamber and the seal diameter is not limited to this. The diameter of the low pressure chamber may be larger than the seal diameter between the valve portion and the valve seat. In this case, since the acting force acting in the valve opening direction is larger than the acting force acting in the valve closing direction, the needle serves as a fuel injection valve for valve opening assistance. Further, the diameter of the low pressure chamber may be smaller than the seal diameter between the valve portion and the valve seat. In this case, since the acting force acting in the valve opening direction is smaller than the acting force acting in the valve closing direction, the needle serves as a valve closing assist fuel injection valve.

  (C) In the fifth to seventh embodiments described above, the square of the diameter of the balance rod is assumed to be the same as the sum of the square of the diameter of the shaft portion and the square of the seal diameter. However, these relationships are not limited to this. The square of the diameter of the balance rod may be larger than the sum of the square of the diameter of the shaft portion and the square of the seal diameter. In this case, since the acting force acting in the valve opening direction is smaller than the acting force acting in the valve closing direction, the needle serves as a valve closing assist fuel injection valve. Further, the square of the diameter of the balance rod may be smaller than the sum of the square of the diameter of the shaft portion and the square of the seal diameter. In this case, since the acting force acting in the valve opening direction is larger than the acting force acting in the valve closing direction, the needle serves as a fuel injection valve for valve opening assistance.

  (D) In the sixth embodiment described above, the aperture is formed on the inner wall of the through hole of the balance rod. Moreover, in 7th Embodiment, the aperture_diaphragm | restriction was formed in the inner wall of the through-hole of a shake absorber. However, the position where the diaphragm is formed is not limited to this. You may form in the inner wall of the communicating hole currently formed in the needle.

  (E) In the above fifth to seventh embodiments, the balance rod is slidably accommodated in the fixed core. However, the part where the balance rod is accommodated is not limited to this. It may be slidable on the inner wall forming the fuel passage of the first housing.

  (F) In the above-described embodiment, a plurality of nozzle holes are formed in the nozzle member. However, the number of nozzle holes formed is not limited to this. There may be one nozzle hole.

  As mentioned above, this invention is not limited to such embodiment, It can implement with a various form in the range which does not deviate from the summary.

1, 2, 3, 4, 5, 6, 7 ... fuel injection valve (fluid control valve),
11, 12, 13, 14, 15, 16, 17 ... balance rod,
163,703 ... through holes (throttle channels),
20, 50 ... housing,
27 ・ ・ ・ Low pressure chamber (third pressure chamber)
28, 444, 68...
301, 601 ... core part (movable core),
302, 602 ... Shaft (movable core)
303, 404 ... valve part (valve),
32, 62 ... Needle chamber (first pressure chamber),
34 ... Core chamber (second pressure chamber),
35, 65 ... fixed core,
36 ・ ・ ・ Coil,
37, 67 ・ ・ ・ Spring (biasing means),
512 ... Fuel passage (second pressure chamber),
64 ... Core chamber (third pressure chamber).

Claims (8)

A housing (20) forming an inlet (211) for introducing fluid, outlets (242, 442) for discharging fluid, and a valve seat (26) provided around the outlet;
A coil (36) that generates a magnetic field when energized;
A fixed core (35) fixed in a magnetic field generated by the coil;
A movable core (301, 302, 401, 402, 403) provided on the valve seat side of the fixed core and attracted to the fixed core side when the coil generates a magnetic field;
A first pressure chamber (32) provided on the valve seat side of the movable core so as to be reciprocally movable integrally with the movable core and formed between the inner wall of the housing when contacting or separating from the valve seat. And a valve body (303, 404) that shuts off or communicates with the outlet.
A third pressure chamber (27) that is slidably provided in the housing or the movable core and communicates with the introduction port and a third pressure chamber (27) that communicates with the outside are provided between the housing and the movable core. Balance rods (11, 12, 13, 14) to be formed into
Urging means (37) for urging the valve body in the direction of the valve seat;
With
In the valve body, a cross-sectional area of a fourth pressure chamber (33) formed between the outer wall (306) of the valve body and the valve seat when the valve body and the valve seat abut is the movable core. Formed so as to be smaller than the cross-sectional area of the portion (302) sliding with the inner wall of the housing,
The fluid control valve, wherein the second pressure chamber accommodating the movable core and the first pressure chamber communicate with each other through a throttle channel (28, 444).   The fluid control valve according to claim 1, wherein a diameter (R1) of the balance rod is equal to a seal diameter (R2) between the valve body and the valve seat. The balance rod is provided separately from the movable core (401, 402, 403), and engages with the movable core while being inserted into a recess (402) formed in the movable core,
The fluid control valve according to claim 1 or 2, wherein the balance rod is formed so as to be allowed to be displaced relative to the movable core. The movable core connects the first inner wall (244) of the housing forming the first pressure chamber and the second inner wall (201) of the housing forming the second pressure chamber. Slidably provided,
4. The fluid control valve according to claim 1, wherein the throttle channel is an orifice that connects the first inner wall and the second inner wall. 5.   The said throttle flow path (444) is formed between the outer wall (304) of the said movable core, and the inner wall (443) of the said housing, The Claim 1 characterized by the above-mentioned. Fluid control valve. A housing (50) forming an inlet (511) through which fluid is introduced, a outlet (242) for leading out the fluid, and a valve seat (56) provided around the outlet;
A coil (66) that generates a magnetic field when energized;
A fixed core (65) fixed in a magnetic field generated by the coil;
A movable core (601, 602) provided on the valve seat side of the fixed core and attracted to the fixed core side when the coil generates a magnetic field;
A first pressure chamber (62) provided on the valve seat side of the movable core so as to be capable of reciprocating integrally with the movable core and formed between the inner wall of the housing when contacting or separating from the valve seat. And a valve body (603) that shuts off or communicates with the outlet.
A through-hole (153, 163, 173) is provided in the housing or the fixed core so as to be slidable and communicates with the second pressure chamber (512) communicating with the introduction port and the first pressure chamber. A balance rod (15, 16, 17) in contact with the end surface (600) of the movable core on the fixed core side;
Urging means (67) for urging the valve body in the direction of the valve seat;
With
The fixed core and the housing form a third pressure chamber (64) that communicates the second pressure chamber and the outside,
In the valve body, a cross-sectional area of a fourth pressure chamber (63) formed between an outer wall (606) of the valve body and the valve seat when the valve body and the valve seat abut is the movable core. Formed so as to be smaller than the cross-sectional area of the portion (602) that slides with the inner wall of the housing,
The fluid control valve characterized in that the first pressure chamber and the second pressure chamber communicate with each other through a throttle channel (68, 163, 703). The cross-sectional area of the balance rod is A1 (m ² ), the cross-sectional area of the movable core that slides on the inner wall of the housing is A2 (m ² ), and the cross-sectional area of the fourth pressure chamber is A3 (m ² ) If the balance rod is
A1 = A2-A3
The fluid control valve according to claim 6, wherein the fluid control valve is formed so as to satisfy the relationship. The minimum cross-sectional area of the throttle channel is A0 (m ² ), the cross-sectional area of the outlet is A4 (m ² ), and the cross-sectional area of the movable core that slides on the inner wall of the housing is A2 (m ² ). And, when the cross-sectional area of the fourth pressure chamber is A3 (m ² ),
The throttle channel is

The fluid control valve according to claim 1, wherein the fluid control valve is formed so as to satisfy the relationship.

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