JP3925799B2 - Fluid injection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluid ejection valve that drives fluid ejection with a plurality of coil portions.
[0002]
[Prior art]
In order to increase the injection amount of the fluid injection valve, it is conceivable to increase the seat diameter of the valve portion formed by the valve member and the valve seat or the lift amount of the valve member. When the seat diameter is increased, the pressure receiving area of the seat portion that receives the fluid pressure increases, so the load of the spring that biases the valve member increases. Therefore, it is necessary to increase the magnetic attractive force for attracting the valve member against the spring load. Further, when the lift amount of the valve member is increased, the gap for attracting the valve member is increased, so that it is necessary to increase the magnetic attractive force.
[0003]
However, when the magnetic attractive force is increased, the inductance of the electromagnetic drive unit of the fluid injection valve is increased, and the rise and fall of the current flowing through the coil is delayed. As a result, the generation and disappearance of dynamic magnetic attraction force is delayed, and there is a problem that the open / close response of the fluid injection valve is lowered.
[0004]
Therefore, in order to improve the open / close response of the fluid injection valve, it is considered to use a plurality of coils (for example, Patent Document 1, Patent Document 2, and Non-Patent Document 1). Note that SAE in Non-Patent Document 1 is an abbreviation for “The Society of Automotive Engineers”.
[0005]
[Patent Document 1]
JP-A-8-326620 [Patent Document 2]
JP-A-60-56137 [Non-patent Document 1]
SAE820203
[0006]
[Problems to be solved by the invention]
In the fluid injection valve of Patent Literature 1, when the valve is opened, a plurality of coils are energized to open with a large magnetic attractive force to improve the valve opening response. After opening the valve, only a part of the plurality of coils is energized in order to keep the valve open. Since the magnetic attractive force generated in the valve-opening holding state is smaller than that at the start of the valve opening, the responsiveness when the valve is closed is improved.
[0007]
However, in the fluid injection valve of Patent Document 1, since a plurality of coils are wound around a common core, the inductance when using a plurality of coils is greater than when using some coils. growing. Therefore, the responsiveness at the time of valve opening which supplies with electricity to a plurality of coils falls.
[0008]
Patent Document 2 or Non-Patent Document 1 discloses a configuration in which a coil is wound around different cores. Compared to a configuration in which a plurality of coils are wound around one common core, the inductance of a single coil unit composed of the core and the coil is small, and even if a plurality of coils are energized simultaneously, the inductance of each coil unit is Since it does not change, the responsiveness when opening and closing the valve is improved.
[0009]
However, as shown in Patent Document 2 and Non-Patent Document 1, when a plurality of coil parts formed by winding a coil around different cores are used for a fluid injection valve, the gap between the fluid and the coil part is sealed. A structure is needed. In the fluid injection valve of Patent Document 2, a seal member such as an O-ring is used to seal between the coil portion and the fluid. If there are many seal portions between the coil portion and the fluid, the number of parts of the seal member increases, and the assembly of the seal member is complicated. Non-Patent Document 1 does not show a structure for sealing between a fluid and a seal portion. If non-patent document 1 is sealed with a sealing member such as an O-ring as in patent document 2, the same problem as in patent document 2 occurs.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fluid ejection valve that improves the opening / closing response of fluid ejection and is easy to seal.
[0010]
[Means for Solving the Problems]
According to invention of Claim 1, since the coil part by which the coil is wound by the different winding core is arrange | positioned in the circumferential direction on the outer periphery of a cylinder member, if it is a fluid injection valve of the same physique, one piece Compared to the case where one coil is wound around the core to form an electromagnetic drive unit, the magnetic path area of the magnetic circuit per coil unit is reduced and the magnetic resistance is increased. Therefore, the inductance of each coil part falls. Since the inductance of each coil portion does not change regardless of the number of coil portions that are energized at the same time, the open / close response of the fluid injection valve is improved by reducing the inductance of each coil portion.
In addition, since fluid flows on the inner peripheral side of the cylindrical member and the coil portion is disposed in the circumferential direction on the outer peripheral side of the cylindrical member, there are few places to seal between the liquid and the plurality of coil portions, and sealing is easy. It is.
[0011]
According to the second aspect of the present invention, since the winding core is formed in a straight line from one end thereof to the winding portion around which the coil is wound, the coil is wound around the jig and the coil is removed from the jig. After that, when the winding core is inserted into the place where the jig is removed, the winding core can be easily inserted.
In this way, the coil can be easily wound because the coil can be inserted after the coil is wound around the jig instead of being wound directly around the coil. Further, when a defect such as disconnection or collapse occurs when winding on a jig, only the coil can be discarded. Therefore, it is possible to reduce the amount of discarded production members.
[0012]
According to the invention of claim 3, the cylindrical member accommodates the fixed core and the movable core, and has the first magnetic part, the magnetoresistive part, and the second magnetic part in this order from the valve seat side. Since the cylindrical member also serves as a part of the sealing member and the magnetic circuit, the number of parts is reduced.
According to the invention described in claim 4, since the inner peripheral wall of the valve housing on the side opposite to the valve seat and the outer peripheral wall of the cylindrical member are welded all around, the inner peripheral wall of the valve housing on the side opposite to the valve seat and the outer periphery of the cylindrical member A sealing member for sealing the wall is unnecessary. Therefore, the number of parts is reduced.
[0013]
Since the inductance of each coil portion does not change even if the energization to the coil portion is interrupted at the same time, the open / close response is improved by performing the energization control to the plurality of coil portions simultaneously as in the invention of claim 5. The magnetic attractive force can be secured while maintaining the above. Furthermore, since the energization control of each coil part is common, energization control is easy.
[0014]
According to the invention described in claim 6, by energizing all the coil portions at the time of opening the valve, it is possible to secure the magnetic attractive force while maintaining the improvement of the valve opening response. In addition, after the valve is opened, energization of a part of the plurality of coil portions is continued and the energization of the remaining coil portions is interrupted to maintain the valve open state. It has become. Accordingly, the valve closing response is improved as compared with the case where all the coil portions are energized.
[0015]
According to the seventh aspect of the present invention, a part of the plurality of coil parts is energized before the valve opening so that the magnetic attractive force required for the valve opening is lower, and then all the coil parts are energized to be opened. Since a magnetic attractive force has already been generated at the time of valve opening by the magnetic coil portion that has been energized in advance, if all the coil portions are energized at the time of valve opening, the valve opening response is further improved. In addition, after the valve is opened, energization of a part of the plurality of coil portions is continued and the energization of the remaining coil portions is interrupted to maintain the valve open state. It has become. Accordingly, the valve closing response is improved as compared with the case where all the coil portions are energized.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A fuel injection valve as a fluid injection valve according to an embodiment of the present invention is shown in FIG. In the present embodiment, the fuel injection valve 10 is applied to a direct injection fuel injection valve for a gasoline engine.
The valve body 12 is fixed to the fuel injection side end inner wall of the valve housing 16 by welding. The valve body 12 has a valve seat 13 on the inner peripheral wall on the injection hole 14 side in the fuel flow direction. The valve body 12 and the valve housing 16 constitute a valve housing described in the claims.
[0017]
As shown in FIG. 1, the valve member 20 has a contact portion 21 that sits on the valve seat 13 at the end portion on the injection hole 14 side. When the contact portion 21 is seated on the valve seat 13, the fuel injection from the nozzle hole 14 is cut off, and when the contact portion 21 is separated from the valve seat 13, fuel is injected from the nozzle hole 14. The valve seat 13 and the valve member 20 constitute a valve portion that opens and closes fuel injection.
[0018]
The cylindrical member 30 is inserted in the inner peripheral wall of the valve housing 16 on the side opposite to the valve seat. The cylindrical member 30 is fixed to the valve housing 16 by the all-around welding 200, and the gap between the valve housing 16 and the cylindrical member 30 is sealed by the all-around welding 200. The cylindrical member 30 includes a first magnetic part 32, a nonmagnetic part 34 as a magnetic resistance part, and a second magnetic part 36 from the nozzle hole 14 side. The nonmagnetic part 34 prevents a magnetic short circuit between the first magnetic part 32 and the second magnetic part 36.
[0019]
The movable core 40 is formed of a magnetic material in a cylindrical shape, and is fixed to the end portion 24 of the valve member 20 on the side opposite to the injection hole by welding. The movable core 40 reciprocates together with the valve member 20. The outflow hole 42 that penetrates the cylindrical wall of the movable core 40 forms a fuel passage that communicates the inside and outside of the cylinder of the movable core 40.
[0020]
The fixed core 44 is formed of a magnetic material in a cylindrical shape. The fixed core 44 is inserted into the cylindrical member 30 and is fixed to the cylindrical member 30 by the all-around welding 202. A space between the cylindrical member 30 and the fixed core 44 is sealed by a circumferential weld 202. The fixed core 44 is installed on the side opposite to the injection hole which is one side in the reciprocating direction of the valve member 20 with respect to the movable core 40 and faces the movable core 40.
[0021]
The adjusting pipe 46 is press-fitted into the fixed core 44 and forms a fuel passage therein. A spring 48 as an urging member is locked to the adjusting pipe 46 at one end and locked to the movable core 40 at the other end. By adjusting the press-fitting amount of the adjusting pipe 46, the load of the spring 48 applied to the movable core 40 can be changed. The movable core 40 and the valve member 20 are biased toward the valve seat 13 on the other side in the reciprocating direction by the biasing force of the spring 48.
[0022]
The coil unit 50 includes a coil 51 and a wound core 52. Each coil is electrically connected in parallel. As shown in FIG. 2, each winding core 52 is formed in an arc shape in cross section, and as shown in FIG. 1, the winding core 52 is formed in a straight line from one end to a winding portion around which the coil 51 is wound. Yes. Three coil portions 50 are arranged in the circumferential direction on the outer peripheral side of the cylindrical member 30. The coil part 50 is formed by first winding the coil 51 on a winding jig and inserting the straight part of the winding core 52 into the wound coil 51.
[0023]
The terminal 62 is insert-molded in the resin housing 60 and is electrically connected to the coil 51. When the coil 51 is energized, a magnetic attractive force acts between the movable core 40 and the fixed core 44, and the movable core 40 is attracted toward the fixed core 44 against the urging force of the spring 48.
[0024]
The filter 70 is accommodated in the fuel inflow member 72 and installed on the fuel upstream side of the fixed core 44. The fuel filter 70 removes foreign matters in the fuel supplied to the fuel injection valve 10. The fuel inflow member 72 is fixed to the tubular member 30 by the all-around welding 204, and the space between the tubular member 30 and the fuel inflowing member 72 is sealed by the all-around welding 204.
[0025]
The fuel flowing into the fixed core 44 through the filter 70 flows between the fuel passage in the adjusting pipe 46, the fuel passage in the movable core 40, the outflow hole 42, and the inner peripheral wall of the valve housing 16 and the outer peripheral wall of the valve member 20. Pass through sequentially. When the valve member 20 is separated from the valve seat 13, the fuel passes through an opening flow path formed between the contact portion 21 and the valve seat 13 and is guided to the injection hole 14.
[0026]
The drive current supplied to the coil unit 50 is controlled by the CPU 100, which is a control device, as shown in FIG. The CPU 100 includes a controller 102 that controls switching of the switching transistor 112. When the controller 102 turns the switching transistor 112 on and off, the drive current flowing through each coil 51 is interrupted. The controller 102 and the switching transistor 112 constitute a switching circuit 110. In the first embodiment, the CPU 100 and the switching transistor 112 are installed outside the fuel injection valve 10.
[0027]
Next, the relationship between the number of coil sections 50 (hereinafter, “the number of coil sections 50” is referred to as the number of poles), the magnetic attractive force, and the current value will be described with reference to FIGS. 4 to 8, the number of turns of each coil 51 is the same regardless of the number of poles. When the number of poles is n, the resistance value of each coil 51 with n poles is set to n times, so that the current value supplied to each coil 51 is reduced to 1 / n, and the total current flowing through the coil section 50 is increased. Is the same regardless of the number of poles.
[0028]
First, as shown in FIG. 4, if the electromotive forces are the same, the static attractive force acting between the movable core 40 and the fixed core 44 decreases as the number of poles increases. In the configuration in which the coils 51 are wound around different winding cores 52 as in the present embodiment and the coil portions 50 are installed in the circumferential direction on the outer peripheral side of the cylindrical member 30, the winding through which the magnetic flux passes for each coil portion 50. Since the rotating core 52 is differently divided, the magnetic path area of each coil portion 50 decreases as the number of poles increases. When the magnetic path area is reduced, the magnetic resistance of each coil portion 50 is increased, so that the static attractive force per pole is decreased as shown in FIG. However, if the number of turns is the same, if the magnetic path area is small and the magnetic resistance is large, the inductance of each coil unit 50 is small.
[0029]
Next, a change in current value at the start of energization is shown in FIG. As described above, when the number of poles increases, the inductance of each coil unit 50 decreases, so that the current value supplied to each coil 51 rises earlier. Then, as shown in FIG. 6, the magnetic attraction force generated by each coil unit 50 rises quickly. However, since the resistance value of each coil 51 is increased as the number of poles is increased, the saturation current value and the magnetic attractive force are decreased.
[0030]
Since the dynamic change in the current value and the magnetic attraction force in all the coil portions 50 is the sum of the dynamic change in the current value and the magnetic attraction force in each coil portion 50, as shown in FIGS. The larger the value, the faster the current value and magnetic attraction rise. Therefore, the valve opening response is improved. If the dynamic suction force rises earlier, the dynamic suction force falls faster, and the valve closing response improves. In the present embodiment, the number of coil portions 50 is set to three in consideration of the coil resistance that generates the necessary magnetic attraction force, the current value, and the number of turns of the coil.
[0031]
In the energization control to each coil 51 described above, energization to all three coil portions 50 was interrupted at the same time. In addition to this, for example, only one of the three coil units 50 may be energized before the valve is opened, and the other two coil units 50 may be energized at the start of the valve opening. By energizing one coil unit 50, a magnetic attractive force necessary for opening the valve is not generated. By energizing one coil unit 50 in advance before the valve is opened, a magnetic attractive force is already generated between the fixed core 44 and the movable core 40 at the start of the valve opening. The valve opening response is further improved by energizing the other two coil portions 50. It is possible to energize the three coil units 50 simultaneously when the valve is opened, without energizing one coil unit 50 in advance before the valve is opened.
[0032]
Further, after the valve is opened, it is only necessary to generate a magnetic attractive force sufficient to maintain the valve open state. Therefore, only one or two of the three coil portions 50 are energized, and the remaining The energization to the coil unit 50 is cut off. By doing so, the magnetic attractive force working at the time of closing the valve is reduced, so that the valve closing response is further improved.
[0033]
In the first embodiment, the winding core 52 is linearly formed from one end to the winding portion of the coil 51. Therefore, the winding core 52 can be easily inserted into the coil 51 after the coil 51 is wound around the winding jig. It is easier to wind around a dedicated winding jig than to wind directly around the winding core 52. Further, when a defect such as disconnection or collapse occurs during winding of the coil 51, only the coil can be discarded. Therefore, it is possible to reduce the amount of members discarded during the production.
[0034]
(Second Embodiment)
A second embodiment of the present invention is shown in FIG. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals. In the second embodiment, the switching circuit 110 shown in FIG. 3 is inserted into the resin housing 60.
[0035]
In the plurality of embodiments described above, the number of the coil portions 50 is made plural, and each coil portion 50 forms a different magnetic circuit, thereby reducing the inductance of the coil portion 50 and improving the open / close response. . Furthermore, since the fuel flows through the cylindrical member 30 and the coil portion 50 is disposed on the outer peripheral side of the cylindrical member 30, there are few places where the fuel and the coil portion 50 are sealed, and sealing is easy.
In the above embodiments, the number of coil portions 5 is three, but the number of coil portions 50 may be two or four or more. What is necessary is just to set the optimal number of the coil parts 50 with respect to the coil resistance which generate | occur | produces a required magnetic attraction force, a current value, and the number of turns of a coil.
[0036]
Further, if possible, a plurality of members constituting the magnetic circuit may be arranged in the circumferential direction similarly to the wound core 52. For example, a plurality of fixed cores and movable cores can be arranged in the circumferential direction. In this case, the number of fixed cores and movable cores may be the same as or different from the number of coil portions 50. When a plurality of fixed cores are arranged in the circumferential direction, the space between the fuel inflow member 72 and the cylindrical member 30 is sealed by welding, so that fuel does not leak from the cylindrical member 30 to the coil portion 50 side. Since the cylindrical member 30 and the valve housing 16 are members that seal the fuel and the coil portion 50, they are not constituted by a plurality of members.
In the plurality of embodiments described above, the present invention is applied to a direct injection fuel injection valve of a gasoline engine. However, the present invention may be applied to a fuel injection valve that injects in an intake pipe in addition to direct injection.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a fuel injection valve according to a first embodiment of the present invention.
2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is a circuit diagram showing a coil section and a switching circuit of the first embodiment.
FIG. 4 is a characteristic diagram showing the relationship between magnetomotive force per pole and static attractive force.
FIG. 5 is a characteristic diagram showing a change in current value per pole.
FIG. 6 is a characteristic diagram showing a change in dynamic attractive force per pole.
FIG. 7 is a characteristic diagram showing changes in the total current value of all poles.
FIG. 8 is a characteristic diagram showing a change in dynamic attractive force of all poles in total.
FIG. 9 is a sectional view showing a switching circuit of a fuel injection valve according to a second embodiment of the present invention.
[Explanation of symbols]
10 Fuel injection valve (fluid injection valve)
12 Valve body 13 Valve seat 14 Injection hole 16 Valve housing 20 Valve member 21 Contact part 40 Movable core 44 Fixed core 48 Spring (biasing member)
50 Coil part 51 Coil (Coil part)
52 Winding core (coil part)
100 CPU (control device)
102 Controller 110 Switching circuit

Claims (7)

A valve portion for injecting fluid;
A winding core, and a coil wound around the winding core, and a plurality of coil portions that open and close the valve portion by magnetic attraction generated by energizing the coil; and
The plurality of coil portions are arranged in the circumferential direction on the outer peripheral side, and a cylindrical member that seals between the fluid flowing on the inner peripheral side toward the valve portion and the plurality of coil portions,
With
The fluid injection valve , wherein the coils of the plurality of coil portions are electrically connected in parallel .   The fluid injection valve according to claim 1, wherein the winding core is formed in a straight line from one end thereof to a winding portion around which the coil is wound. A valve housing having a valve seat;
A valve member that forms the valve seat and the valve portion, shuts off fluid injection by sitting on the valve seat, and allows fluid injection by separating from the valve seat;
A movable core installed on the valve seat side of the valve member and reciprocating with the valve member;
A fixed core installed on one side of the reciprocating movement direction with respect to the movable core and facing the movable core;
The cylindrical member houses the fixed core and the movable core on the inner peripheral side, and has a first magnetic part, a magnetoresistive part, and a second magnetic part in this order from the valve seat side. The fluid injection valve according to claim 1 or 2.   The fluid injection valve according to claim 3, wherein the inner peripheral wall of the valve housing on the side opposite to the valve seat and the outer peripheral wall of the cylindrical member are welded all around.   5. The fluid injection valve according to claim 1, further comprising: a control device that controls energization of the plurality of coil portions, wherein the control device simultaneously interrupts energization of the plurality of coil portions. .   The controller includes a control device that controls energization of the plurality of coil portions, and the control device energizes all the coil portions when the valve is opened, and continues energization to a part of the plurality of coil portions after the valve is opened. The fluid injection valve according to any one of claims 1 to 4, wherein the valve opening state is maintained by interrupting energization to the portion.   A control device that controls energization of the plurality of coil portions, and the control device energizes a part of the plurality of coil portions before opening the valve so as to be less than a magnetic attractive force necessary for valve opening; The coil portion is energized to open the valve, and after opening, the energization to a part of the plurality of coil portions is continued and the energization to the remaining coil portions is interrupted to maintain the valve open state. The fluid injection valve according to any one of claims 1 to 4.

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