JP7298184B2 - injector - Google Patents

Description

The present disclosure relates to injectors.

Patent Literature 1 discloses a fuel injection valve having two valve bodies, a sub-valve body and a main valve body. In this fuel injection valve, a sub-valve having a small opening is driven by an electromagnetic force to open the valve. By opening the sub-valve, the pressure difference in the main valve is released, and the main valve can be easily moved. I am opening the valve.

JP 2015-45239 A

However, if the fuel is not a liquid but a gas, the gas is a compressible fluid, so there is a problem that it is difficult to control the opening and closing force of the valve by using the pressure difference across the valve. . Therefore, there is a demand for a fuel injection valve that has two valve bodies, a sub-valve body and a main valve body, and that can be used even when the fuel is gas.

According to one aspect of the present disclosure, an injector (100) is provided. This injector is housed in a housing (10) having a first injection port (10h), a housing (90) provided on the opposite side of the housing from the first injection port, the housing and the housing, and A needle assembly (20, 30, 40, 50) that slides within the housing and the casing and opens and closes the first injection port, and an electric actuator that is arranged outside the casing and drives and moves the needle assembly. (60), and a fixed core (70) that is housed in the housing and restricts the movement of the needle assembly, wherein the needle assembly comprises an outer needle (20) that opens and closes the first injection port; An inner needle (30) for opening and closing a second injection port (20h), comprising: an inner needle housed inside the outer needle and sliding in the outer needle; and a movable core (40) driven by the electric actuator, the movable core (40) moving the inner needle together with the stopper. A first outer needle portion (20a) having an injection port, a second outer needle portion (20b) on the opposite side of the second injection port, and an abutting portion arranged at the inner upper end portion of the second outer needle portion. a contact portion (22) that contacts the inner needle when the inner needle moves in the valve opening direction of the second injection port, and the contact portion is the outer portion of the inner needle. The material forming the inner needle, the first outer needle portion, and the contact portion has a larger Vickers hardness than the material forming the second outer needle portion. The movable core moves the inner needle to open the second injection port by driving the electric actuator, and moves the outer needle after the inner needle contacts the contact portion. The first injection port is opened. According to this aspect, the opening and closing of the two needles, the inner needle and the outer needle, can be controlled by one movable core regardless of whether the fuel is liquid fuel or gaseous fuel.

1 is a schematic configuration diagram of an injector of a first embodiment; FIG. FIG. 10 is an explanatory view showing a state when the electric actuator is driven to open the inner needle and the inner needle comes into contact with the contact portion; FIG. 10 is an explanatory view showing a state when the outer needle is opened and the movable core comes into contact with the fixed core; FIG. 10 is an explanatory diagram showing a state in which the inner needle and the outer needle are lowered after the movable core contacts the fixed core; FIG. 10 is an explanatory view showing a state in which the driving of the electric actuator is stopped and the inner needle is closed; FIG. 10 is an explanatory view showing a state in which driving of the electric actuator is stopped and the outer needle is closed; 4 is a time chart showing the drive voltage of the electric actuator and the open/closed states of the inner needle and the outer needle; FIG. 10 is an explanatory diagram showing a state in which the movable core is moved in the direction of the outer needle; FIG. 4 is an explanatory view showing a method of welding a stopper to an inner needle; FIG. 4 is an explanatory view showing the needle assembly after stopper welding; FIG. 5 is a schematic configuration diagram of an injector of a second embodiment; FIG. 10 is a cross-sectional view of the injection port of the injector of the second embodiment;

・First embodiment:
As shown in FIG. 1, the injector 100 includes a housing 10, an outer needle 20, an inner needle 30, a movable core 40, a stopper 50, an electric actuator 60, a fixed core 70, springs 80a and 80b, A housing 90 is provided. A combination of the outer needle 20, the inner needle 30, the movable core 40, and the stopper 50 is called a "needle assembly".

The housing 10 is a tubular member having a first nozzle hole 10h at one end. The housing 10 is made of, for example, martensitic non-magnetic stainless steel. A housing 90 is provided on the opposite side of the housing 10 to the first injection port 10h. The housing 90 includes a substantially cylindrical first magnetic portion 90a, a second magnetic portion 90c, and a non-magnetic portion 90b. The first magnetic portion 90a and the second magnetic portion 90c are substantially cylindrical members made of ferritic magnetic stainless steel. The non-magnetic portion 90b is a substantially cylindrical member provided between the first magnetic portion 90a and the second magnetic portion 90c, and is made of austenitic non-magnetic stainless steel. A needle assembly, a fixed core 70, and springs 80a and 80b are housed inside the housing 10 and the housing 90. As shown in FIG.

The outer needle 20 is a hollow cylindrical member having a second injection port 20h. The outer needle 20 includes a first outer needle portion 20a, a second outer needle portion 20b, and a contact portion 22. As shown in FIG. The first outer needle portion 20a has a second injection port 20h that communicates with the first injection port 10h, functions as a valve seat, and functions as a valve body that opens and closes the first injection port 10h. Therefore, the first outer needle portion 20a is made of martensitic non-magnetic stainless steel so as to be resistant to wear. The Vickers hardness of the first outer needle portion 20a is 600, for example. The second outer needle portion 20b is made of ferritic magnetic stainless steel. The Vickers hardness of the second outer needle portion 20b is 170, for example. An opening 20c is formed in the side surface of the second outer needle portion 20b. This opening 20c communicates the inside and the outside of the outer needle 20 with each other. The first outer needle portion 20a and the second outer needle portion 20b are welded together, and the inside thereof is hollow. A contact portion 22 is provided at the end portion of the inside of the first outer needle portion 20a and the second outer needle portion 20b on the side opposite to the first outer needle portion 20a. The contact portion 22 is made of martensitic non-magnetic stainless steel. The Vickers hardness of the contact portion 22 is 600, for example.

The inner needle 30 includes a first inner needle portion 30a, a second inner needle portion 30b, and a third inner needle portion 30c in this order from the second injection port 20h side of the outer needle 20. As shown in FIG. Among them, the first inner needle portion 30 a and the second inner needle portion 30 b are housed inside the outer needle 20 and slide inside the outer needle 20 . The third inner needle portion 30c protrudes outside the outer needle 20 from the side of the outer needle 20 opposite to the second injection port 20h. The first inner needle portion 30a functions as a valve element that opens and closes the second injection port 20h. The second inner needle portion 30b has a contact portion 30d that contacts the contact portion 22 when the inner needle 30 moves in the valve opening direction. The inner needle 30 is made of martensitic non-magnetic stainless steel so that the contact portion 30d is not worn. The Vickers hardness of the inner needle 30 is 600, for example. A stopper 50 is attached by welding to the side of the third inner needle portion 30c opposite to the second inner needle portion 30b. The stopper 50 may be attached to the third inner needle portion 30c by screwing or pinning by a method other than welding.

A movable core 40 is provided between the outer needle 20 and the stopper 50 . The movable core 40 includes a magnetic movable core portion 40a, a first movable core portion 40b, and a second movable core portion 40c. The first movable core portion 40b is positioned around the stopper 50, and the magnetic movable core portion 40a is arranged on the outer edge side of the first movable core portion 40b. The second movable core portion 40c is arranged on the outer needle 20 side of the first movable core portion 40b. The magnetic movable core portion 40a is made of ferritic magnetic stainless steel and has a Vickers hardness of 170, for example. The first movable core portion 40b and the second movable core portion 40c are made of non-magnetic stainless steel and have a Vickers hardness of 600, for example.

The second movable core portion 40c includes a contact portion 40d that contacts the fixed core 70 when the needle assembly moves in the valve opening direction, and an opening 40e into which the stopper 50 can be inserted. A contact portion 42 is in contact with the bottom of the opening 40e. The contact portion 42 is provided around the third inner needle portion 30c. The contact portion 42 is made of non-magnetic stainless steel and has a Vickers hardness of 600, for example.

The first movable core portion 40b has a hole 40f and a recess 40g into which the outer needle 20 can be inserted. A plurality of holes 40f are formed along the circumference with the inner needle 30 as the central axis. The hole 40f is formed parallel to the movement direction of the inner needle 30, communicates the opening 40e with the outside of the outer needle 20, and functions as a fuel flow path fp4 as described later.

The fixed core 70 is a cylindrical member housed inside the housing 90, and is provided at a position that restricts movement so that the needle assembly does not move in the valve opening direction beyond a certain amount. The fixed core 70 includes a first fixed core portion 70a with which the magnetic movable core portion 40a abuts, and a second fixed core portion 70b with which the first movable core portion 40b abuts. The first fixed core portion 70a is made of, for example, ferritic magnetic stainless steel. The Vickers hardness of the first fixed core portion 70a is 170, for example. The second fixed core portion 70b is made of martensitic non-magnetic stainless steel. The Vickers hardness of the second fixed core portion 70b is 600, for example. By configuring the fixed core 70 with such a material, the members of the movable core 40 that contact each other, for example, the magnetic movable core portion 40a and the first fixed core portion 70a, and the first movable core portion 40b and the second fixed core portion 40a, can be arranged. The core portion 70b is made of the same material and has substantially the same Vickers hardness. As a result, wear of the movable core 40 and the fixed core 70 due to the collision of the movable core 40 with the fixed core 70 can be suppressed.

The electric actuator 60 is formed of, for example, a solenoid and arranged around the housing 90 . A magnetic member 11 made of magnetic stainless steel is provided outside the electric actuator 60 . When the electric actuator 60 is energized, magnetic flux is generated inside and outside the electric actuator 60 as indicated by the arrows in FIG. A magnetic circuit is formed through and causes the movable core 40 to move. Electric actuator 60 also moves inner needle 30 and outer needle 20 via movement of movable core 40 . Details of this operation will be described later.

The spring 80a biases the needle assembly in the valve opening direction, and the spring 80b biases the needle assembly in the valve closing direction.

Next, the fluid flow paths fp1 to fp6 in the injector 100 will be described. Inside the injector 100, flow paths fp1 to fp6 are formed as described below. The flow path fp1 is formed by the space inside the cylinder of the fixed core 70 . The flow path fp2 is formed by the space between the stopper 50 and the non-magnetic portion 90b. The flow path fp3 is formed by the opening 40e of the first movable core portion 40b. The flow path fp4 is formed by the hole 40f of the first movable core portion 40b. Flow path fp5 is formed by the space between outer needle 20 and housing 10 . Flow path fp6 is formed by a space between outer needle 20 and inner needle 30 . The flow channel fp5 and the flow channel fp6 are in communication with each other through the opening 20c. When the outer needle 20 is opened, the fluid is injected from the first injection port 10h through the flow paths fp1 to fp5. When the inner needle 30 is opened, the fluid passes through the flow paths fp1 to fp5, the opening 20c, the flow path fp6, the second injection port 20h, and is jetted from the first injection port 10h.

Next, valve opening conditions for the inner needle 30 and the outer needle 20 will be described. Ds is the diameter of the contact portion between the inner needle 30 and the outer needle 20 when the inner needle 30 is seated on the outer needle 20, and the diameter of the contact portion between the outer needle 20 and the housing 10 when the outer needle 20 is seated on the housing 10. is Db, L is the lift amount until the inner needle 30 opens from the seated state and contacts the contact portion 22, Fsp is the biasing force of the spring 80b, k is the elastic modulus, F is the attraction force of the electric actuator 60, Let Ff be the fuel pressure. The elastic modulus k is a value determined by the material and shape of the second outer needle portion 20 b and the contact portion 22 . The condition for opening the inner needle 30 is
F>Ss×Ff+Fsp (1)
is. Here, Ss is the sheet area of the inner needle 30, and Ss=π×Ds ² /4.
In order for the outer needle 20 not to open, the following conditions must be satisfied.
(Sb−Ss)×Ff>(F×L×k) ^1/2 (2)
Here, Sb is the sheet area of the outer needle 20, and Sb=π×Db ² /4. Note that Db>Ds and Sb>Ss. By doing so, the valve closing force acting on the inner needle 30 that opens the valve by the electric actuator 60 when the valve opening force is small can be reduced, and the inner needle can be easily opened. Further, since the valve closing force due to the fuel pressure acting on the outer needle 20 can be set large, it is possible to easily create a state in which only the inner needle 30 is opened.

Next, the conditions for opening both the inner needle 30 and the outer needle 20 are
F>(Sb−Ss)×Ff+Fsp (3)
is.

For example, if Ds is 1.2 mm, Db is 4.6 mm, fuel pressure Ff is 1.1 MPa, biasing force of spring 80b is 3 N, lift amount L is 0.15 mm, and elastic coefficient k is 4.5×10 ⁴ , The attractive force F of the electric actuator 60 required to open the inner needle 30 is 4.24N. At this time, the left side of the equation (2) is 17.04N and the right side is 5.3N, so the equation (2) is satisfied. Therefore, the inner needle 30 is opened, but the outer needle 20 is not opened. The attractive force F of the electric actuator 60 required to open the outer needle 20 is 20.04N from equation (3). It should be noted that the attraction force F of the electric actuator 60 can be easily controlled by the drive current that drives the electric actuator 60 .

・Opening of the inner needle 30:
A voltage is applied to the electric actuator 60 to make the attraction force F of the electric actuator 60 greater than or equal to the force for opening the inner needle 30 . It should be noted that the suction force F at this time is less than the force for opening the outer needle 20 . As shown in FIG. 2, the electric actuator 60 moves the movable core 40 in the valve opening direction (upward in the drawing), and the movable core 40 moves the stopper 50 upward in the drawing. Since the stopper 50 and the inner needle 30 are fixed by welding, the inner needle 30 also moves upward to open the second injection port 20h. That is, the inner needle 30 is opened. At this time, the fluid passes through the flow paths fp1 to fp5, the opening 20c, the flow path fp6, the second injection port 20h, and is jetted from the first injection port 10h.

If the attraction force F of the electric actuator 60 is greater than or equal to the force that causes the inner needle 30 to open, but less than the force that causes the outer needle 20 to open, the inner needle 30 moves further upward. be moved. When the contact portion 30d of the inner needle 30 comes into contact with the contact portion 22, the inner needle 30 no longer opens. At this time, the contact portion 30 d may apply a large impact load to the contact portion 22 . However, in the present embodiment, the abutting portion 30d of the inner needle 30 and the abutting portion 22 are both made of martensitic stainless steel having a high Vickers hardness, so they are less likely to wear out.

Further, when a voltage is applied to the electric actuator 60 and the attractive force F of the electric actuator 60 becomes greater than or equal to the force for opening the outer needle 20, the electric actuator 60 moves the movable core 40 to the fixed core 70 as shown in FIG. , and the stopper 50 and the inner needle 30 are moved upward in the drawing. At this time, the outer needle 20 receives an upward force from the inner needle 30 via the contact portion 22 and moves upward, opening the first injection port 10h and opening the outer needle 20 . The fluid is not only ejected from the first nozzle hole 10h via the second nozzle hole 20h, but is also ejected from the first nozzle hole 10h from the flow paths fp1 to fp5 without passing through the second nozzle hole 20h.

When the contact portion 40d of the movable core 40 collides with the fixed core 70, the movable core 40 stops moving upward. In the present embodiment, both the first movable core portion 40b having the contact portion 40d of the movable core 40 and the second fixed core portion 70b of the fixed core 70 are made of martensitic stainless steel having a high Vickers hardness. Therefore, even if the contact portion 40d collides with the fixed core 70, the contact portion 40d is less likely to be worn.

After the contact portion 40d of the movable core 40 collides with the fixed core 70, the inner needle 30 and the stopper 50 move upward once due to inertia force, and the contact portion 42 moves from the second movable core portion 40c. Separate. After that, the stopper 50 and the inner needle 30 move downward due to the pressure of the fluid and the biasing force of the spring 80b, and as shown in FIG. 4, the contact portion 42 collides with the second movable core portion 40c. As a result, the outer needle 20 is opened with a constant size. In addition, since the contact portion 42 and the second movable core portion 40c are both made of martensitic stainless steel having a high Vickers hardness, the contact portion 42 collides with the second movable core portion 40c. Both are hard to wear. In FIG. 4 and subsequent figures, some reference numerals and the flow of fuel are omitted because the figures are difficult to see.

・Closing the inner needle 30:
When the voltage application to the electric actuator 60 is stopped, the attractive force F of the electric actuator 60 disappears. As a result, the stopper 50 and the inner needle 30 move downward due to the pressure of the fluid and the biasing force of the spring 80b. As shown in FIG. 5, the first inner needle portion 30a of the inner needle 30 is seated on the first outer needle portion 20a of the outer needle 20 to close the second injection port 20h of the outer needle 20, thereby closing the inner needle 30. speak up. At this time, since the first inner needle portion 30a and the first outer needle portion 20a are both made of martensitic stainless steel having a high Vickers hardness, the first inner needle portion 30a is the first outer needle portion 20a. Even if you sit on it, it is hard to wear. As can be seen from FIG. 5, the outer needle 20 is not supported by any member. Also, the stopper 50 and the inner needle 30 move downward due to the pressure of the fluid and the biasing force of the spring 80b. Therefore, it is difficult to maintain the state shown in FIG. 5, and then the outer needle 20 moves downward together with the stopper 50 and the inner needle 30 .

- Closure of the outer needle 20:
When the stopper 50 and the inner needle 30 move further downward due to the pressure of the fluid and the biasing force of the spring 80b, the outer needle 20 moves downward. As a result, as shown in FIG. 6, the first outer needle portion 20a of the outer needle 20 is seated on the housing 10 to close the first injection port 10h of the housing 10 and the outer needle 20 is closed. At this time, since both the first outer needle portion 20a and the housing 10 are made of martensitic stainless steel having a high Vickers hardness, they are not easily worn.

FIG. 7 is a time chart showing the relationship between the drive voltage of the electric actuator 60 and the open/closed states of the inner needle 30 and the outer needle 20. As shown in FIG. By increasing the drive voltage in stages, that is, by first applying a small drive voltage to the electric actuator 60, the inner needle 30 is opened as shown in FIG. By doing so, the outer needle 20 can be opened as shown in FIG. When the valve is closed, the application of voltage to the electric actuator 60 is stopped, so that the inner needle 30 is closed as shown in FIG. 5, and then the outer needle 20 is closed as shown in FIG. can be done. Thus, according to this embodiment, by controlling the driving voltage of the electric actuator 60, the opening and closing of the inner needle 30 and the outer needle 20 can be controlled.

When welding the stopper 50 to the inner needle 30, first, as shown in FIG. move. Then, the third inner needle portion 30c is exposed. As shown in FIG. 9 with the third inner needle portion 30c exposed, the stopper 50 is attached to the third inner needle portion 30c and welded from the side surface of the stopper 50. As shown in FIG. FIG. 10 shows a state in which the position of the movable core 40 is moved so that the movable core 40 and the contact portion are in contact with each other. Since the third inner needle portion 30 c to which the stopper 50 is attached can be exposed from the movable core 40 in this manner, the stopper 50 can be welded to the inner needle 30 while the stopper 50 is exposed from the movable core 40 . In addition, since the axial length of the inner needle 30 can be shortened, the injector 100 can be made compact. Furthermore, when the stopper 50 is welded to the inner needle 30 , it is possible to prevent the stopper 50 from coming off due to the impact when the movable core 40 collides with the fixed core 70 .

As described above, according to the first embodiment, since the opening and closing of the inner needle 30 and the outer needle 20 can be controlled by one movable core 40, two movable cores, the movable core for the inner needle 30 and the movable core for the outer needle, are used. The cost can be reduced rather than providing.

Further, according to the first embodiment, the valve opening force of the inner needle 30 is transmitted to the outer needle 20 using the pressure of the fuel, and the voltage applied to the electric actuator 60 is used instead of the configuration for opening the outer needle 20. By moving the movable core 40, the opening and closing of the inner needle 30 and the outer needle 20 can be controlled. Therefore, the fuel injected by the injector 100 is not limited to liquid, and may be gas, which is a compressible fluid.

According to the first embodiment, the first injection hole 10h and the second injection hole 20h can be provided on one axis, so the injector 100 can be made smaller.

・Second embodiment:
In the injector 100 of the second embodiment shown in FIG. 11, both the first injection hole 10h and the second injection hole 20h are provided in the housing 10. As shown in FIG. In 2nd Embodiment, the same code|symbol as 1st Embodiment is used. Both the first injection port 10 h and the second injection port 20 h are provided in the housing 10 . FIG. 12 shows the XII-XII section of FIG. As can be seen from FIG. 12, the second nozzle hole 20h has a circular shape, and the first nozzle hole 10h has an arc shape, and a plurality of them are provided around the second nozzle hole 20h. formed. The first injection port 10 h is opened and closed by the outer needle 20 of the needle assembly, and the second injection port is opened and closed by the inner needle 30 sliding inside the outer needle 20 . Both the first injection port 10h and the second injection port 20h may be formed in the housing 10 as in the second embodiment, or the first injection port 10h may be formed in the housing 10 as in the first embodiment. , the second injection port 20h may be formed in the outer needle 20, and the first injection port 10h and the second injection port 20h may be communicated with each other.

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the scope of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each form described in the outline of the invention are used to solve some or all of the above problems, or Alternatively, replacements and combinations can be made as appropriate to achieve all. Also, if the technical features are not described as essential in this specification, they can be deleted as appropriate.

REFERENCE SIGNS LIST 10 housing 10h first injection port 20 outer needle 20h second injection port 22 contact portion 30 inner needle 40 movable core 42 contact portion 50 stopper 60 electric actuator 70 fixed core 90 housing 100 injector

Claims (8)

An injector (100) for ejecting a fluid,
a housing (10) having a first nozzle hole (10h);
a housing (90) provided on the opposite side of the housing from the first injection port;
a needle assembly (20, 30, 40, 50) housed in the housing and the housing, sliding in the housing and the housing, and opening and closing the first injection port;
an electrical actuator (60) located outside the housing for driving movement of the needle assembly;
a fixed core (70) that is housed in the housing and restricts movement of the needle assembly;
with
The needle assembly is
an outer needle (20) for opening and closing the first injection port;
an inner needle (30) for opening and closing a second injection port (20h), the inner needle being housed inside the outer needle and sliding within the outer needle;
a stopper (50) provided on the side of the inner needle opposite to the second injection port;
a movable core (40) driven by the electric actuator for moving the inner needle together with the stopper;
has
The outer needle includes a first outer needle portion (20a) having the second injection port, a second outer needle portion (20b) opposite to the second injection port, and an inner upper end portion of the second outer needle portion. an abutment portion (22) that abuts against the inner needle when the inner needle moves in the valve-opening direction of the second injection port;
the abutting portion has an opening through which a portion of the inner needle having a reduced outer diameter passes;
A material forming the inner needle, the first outer needle portion, and the contact portion has a higher Vickers hardness than a material forming the second outer needle portion,
The movable core moves the inner needle to open the second injection port by driving the electric actuator, and moves the outer needle to open the second injection port after the inner needle contacts the contact portion. opening the first injection port;
injector. The injector of claim 1, comprising:
The injector, wherein the stopper is welded to the inner needle. 3. The injector according to claim 1 or 2,
The injector, wherein the first outer needle portion and the second outer needle portion are welded together. The injector according to any one of claims 1 to 3,
The injector, wherein the stopper can be exposed from the movable core when the needle assembly is removed from the housing. The injector according to any one of claims 1 to 4,
The injector, wherein the seat area of the inner needle is smaller than the seat area of the outer needle. The injector according to any one of claims 1 to 5,
The injector, wherein the second injection port is provided in the outer needle and communicates with the first injection port. The injector according to any one of claims 1 to 5,
The injector, wherein the second injection port is provided in the housing. The injector according to any one of claims 1 to 7,
The injector, wherein the fluid is gas.

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