JP2001140726A - Valve device and fuel injector using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve device and a fuel injector in which a valve member works normally and fluid may not be leaked even though valve bodies are displaced. SOLUTION: As a valve body, a cross valve 30 has a first valve body 31 and a second valve body 35. A first ball valve member 40 and a second ball valve member 41 can be moved independently. The first ball valve member 40 can be seated on a first valve seat 32, and the second ball valve member 41 can be seated on a second valve seat 36. Even though the positions of the valve bodies are displaced along abutting surfaces 31a, 35a, both the ball valve members are displaced along the abutting surfaces 31a, 35a so as to prevent the fixing of both the ball valve members between the valve bodies. As a result, even though the positions of both the valve bodies are displaced, a fuel passage can be certainly changed by the cross valve 30. Even though the positions of both the valve bodies are displaced, the abutting surface 31a and abutting surface 35a may not be separated from each other, so that fuel can be prevented from being leaked from a clearance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device and a fuel injection device for an internal combustion engine using the valve device (hereinafter referred to as an "internal combustion engine").

[0002]

2. Description of the Related Art Conventionally, various three-way valves have been disclosed as valve devices for switching a flow path by moving a valve member by a driving force generated by an electric drive unit. The fuel injection device disclosed in Japanese Patent Application Laid-Open No. 61-244864 uses a three-way valve that drives a valve member by the driving force of an electromagnetic valve. Further, the fuel injection device disclosed in European Patent Application Publication No. 816670 and the drawings uses a three-way valve that drives a valve member by a driving force generated by extension of a piezoelectric element.

FIG. 14 shows an example in which a ball valve member is used as a valve member in such a three-way valve. The valve body includes a first valve body 201 and a second valve body 203 formed of separate members. The two valve bodies are positioned by fitting pins 205 into holes 206 respectively formed in the two valve bodies. A piston 209 is provided on the ball valve member side of the piezoelectric element 208. Piston 209
Reciprocates with the piezoelectric element 208 as the piezoelectric element 208 expands and contracts. When the piezoelectric element 208 is in a discharged state,
The ball valve member 207 is seated on the first valve seat 202 by the fluid pressure in the second passage 212, the first passage 211 is closed, and the second passage 212 and the third passage 213 communicate with each other. When the piezoelectric element 208 is charged, the piezoelectric element 208 is extended, and the ball valve member 207 is seated on the second valve seat 204. Then, the second passage 212 is closed, and the first passage 211 and the third passage 213 communicate with each other.

[0004]

However, if the amount of movement of the ball valve member 207 moving between the first valve seat 202 and the second valve seat 204 is smaller than the clearance between the pin 205 and the hole 206, the two If there is a processing error in the valve body, or if the first valve body 201 and the second valve body 203 are displaced along their contact surfaces during or after assembling as shown in FIG. May be fixed between the conical slopes of both valve bodies. Further, when the conical slopes of the two valve bodies come into contact with the valve member, the two valve bodies do not adhere to each other, and there is a possibility that fluid may leak from between the two valve bodies. For example, when the apex angle of the conical slope of both valve bodies is 90 ° and the movement amount of the ball valve member 207 is 20 μm, the positions and shapes of the pins 205 and the holes 206 are all processed with high precision. Also, if the radial clearance between the pin 205 and the hole 206 is larger than 20 μm, the two valve bodies are displaced along the contact surface of each other, so that the ball valve member 207 is fixed as described above, or fuel leakage occurs. Can occur.

In the three-way valve disclosed in Japanese Patent Application Laid-Open No. 9-184463, a valve body housed in a valve chamber formed in a valve body is moved from outside the valve chamber by a push rod, and a first valve is provided. The seat is selectively seated on the valve seat or the second valve seat. According to this structure, it is impossible to integrally form the first valve body having the first valve seat and the second valve body having the second valve seat. For this reason, it is unavoidable that the shaft center shifts between the two valve seats. The misalignment between the two valve seats causes an axial misalignment between at least one of the valve seats and the valve body. Therefore, there is a problem in that the seating posture of the valve member is disturbed and seating is incomplete, causing fuel leakage. Further, when correcting the displacement of the axis between the valve body and the valve seat by the hydraulic pressure or the force of the push rod given as the seating force, the valve member changes its posture after once abutting on the valve seat. There has been a problem that the members and the valve seat are likely to be worn.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve device which operates normally even if the valve bodies are displaced from each other, does not cause fluid leakage, and prevents an increase in wear of the valve body and the valve member. And a fuel injection device.

[0007]

According to the valve device of the present invention, the valve body has the first valve body and the second valve body, and the first abutment which can be seated on the first valve seat. Part and second
The relative position with respect to the second contact portion that can be seated on the valve seat is variable according to the relative position of both valve seats. Even if the positions of both valve bodies are shifted, the positions of both contact parts are shifted accordingly.
The valve member is seated on the first valve seat according to the position of the first valve seat,
The second contact portion is seated on the second valve seat in accordance with the position of the second valve seat. Since normal seating is realized in this manner, the valve member does not change its posture after sitting on the valve seat. Therefore, it is possible to prevent the positions of the two valve bodies from being shifted from each other and to increase the wear amount of the valve body and the valve member. In addition, fluid leakage can be prevented by normal seating. Further, even if the positions of both valve bodies are shifted, fluid leakage can be prevented, so that the design tolerance of the members constituting the valve device can be increased. Therefore, processing of the valve device becomes easy.

According to the valve device of the second aspect of the present invention,
The valve member has a first valve member and a second valve member that can move independently of each other. Even if the positions of both valve bodies are shifted, the positions of both valve members are shifted accordingly, thereby securing a space where both valve members can move and preventing both valve members from being fixed between both valve bodies. it can. Therefore, the flow path can be switched by moving the two valve members. Further, leakage of fluid from between the two valve bodies is prevented.
Further, even if the positions of the two valve bodies are shifted, fluid leakage can be prevented and the flow path can be switched, so that the design tolerance of members constituting the valve device can be increased. Therefore,
Processing of the valve device becomes easy.

According to the valve device of the third aspect of the present invention,
Since both valve members are formed in a spherical shape, processing of the valve members is easy. According to the valve device according to claim 4 of the present invention, since both valve members are formed in a hemispherical shape and the planar outer walls of both valve members face each other, when the valve member is seated once on the valve seat,
It is possible to stabilize the positional relationship between the valve member and the two valve seats when the open / close valve is operated thereafter. Therefore, it is possible to more effectively prevent the positions of the two valve bodies from being shifted from each other and increasing the amount of wear of the valve bodies and the valve members.

[0010] According to the valve device of claim 5 of the present invention,
Since there is provided an urging member for urging one of the two contact portions toward the first valve seat located on the side of the low-pressure fluid outflow passage,
Even when the pressure difference between the fluid outflow passage and the fluid inflow passage is small, the first valve member can be reliably seated on the first valve seat.

According to the valve device of claim 6 of the present invention,
One of the first and second valve seats is formed in a conical shape, and the other is formed in a planar shape. On the other hand, the end surface on the valve seat side formed in a conical shape of the valve member is formed on a spherical surface,
The end face on the valve seat side formed in a planar shape is formed in a planar shape. That is, since the end surface of the valve member on the valve seat side formed in a planar shape is formed in a planar shape, and a part of the end surface is seated on the valve seat formed in a planar shape, the first contact portion and the second contact portion are formed. The relative position of the contact portion is variable according to the displacement of both valve seats. Therefore, even if the position of the second valve seat is shifted with respect to the first valve seat, the valve member normally seats on both valve seats. Since the valve member is formed of a single member, the behavior of the valve member is stable. Therefore, it is possible to more effectively prevent the positions of the two valve bodies from being shifted from each other and increasing the amount of wear of the valve bodies and the valve members.

According to the valve device according to claim 7 of the present invention,
Since the piezoelectric element is used as the drive source of the electric drive unit, the responsiveness of switching the flow path of the valve device is improved. Claim 8 of the present invention
According to the described valve device, the end of the piston that transmits the driving force to the valve member, which is in contact with the valve member, is formed on a plane, and the end of the valve member, which contacts the piston, is formed in a planar shape. Wear of the piston and the valve member can be prevented.

According to the fuel injection device of the ninth aspect of the present invention, a control pressure chamber for applying fuel pressure to the injection hole valve member in a direction to close the injection hole is provided. The communication between the control pressure chamber and the high-pressure fuel passage is interrupted while the control pressure chamber is communicated with the low-pressure fuel passage. This valve device is a so-called three-way valve. Therefore, by controlling the pressure in the control pressure chamber with the valve device, the injection hole valve member opens and closes the injection hole, and fuel is injected into the cylinder of the internal combustion engine.

[0014] Even if the positions of the two valve bodies of the valve device are displaced, the abutting portions are displaced with the displacement of the two valve bodies, thereby increasing the wear of the valve member and the two valve bodies. Further, it is possible to prevent the valve member from being fixed between the two valve bodies and prevent the fuel from leaking from between the first valve body and the second valve body. Therefore, the fuel pressure in the control pressure chamber is adjusted with high accuracy by the valve device, and the opening and closing of the injection hole can be controlled in accordance with the desired fuel injection characteristics. In addition, the said valve device is Claim 10-1.
6, the fuel pressure in the control pressure chamber is adjusted with high precision in addition to the effects of claims 2 to 8, and the injection hole is adjusted to a desired fuel injection characteristic. The opening and closing control can be effected.

According to the fuel injection device of the present invention, since the piezoelectric element is used as the drive source of the electric drive unit, the responsiveness of switching the flow path of the valve device is improved. As a result, the opening / closing response of the injection hole is improved. Further, the seat diameter of the second contact portion that closes the high-pressure fuel passage by sitting on the second valve seat is the seat diameter of the first contact portion that closes the low-pressure fuel passage by sitting on the first valve seat. Since
The second contact portion can be seated on the second valve seat with a small driving force of the electric drive portion.

According to another aspect of the present invention, there is provided a control pressure chamber which communicates with a high pressure fuel passage and applies fuel pressure to an injection hole valve member in a direction to close the injection hole. The device connects or disconnects the control pressure chamber and the low-pressure fuel passage. With the above valve device,
By controlling the pressure in the control pressure chamber, the injection hole valve member opens and closes the injection hole, and fuel is injected into the cylinder of the internal combustion engine. This valve device is a so-called two-way valve.

Here, the communication between the control pressure chamber and the low-pressure fuel passage is cut off when the valve member of the valve device is driven by the electric drive unit and seats on the first valve seat and the second valve seat. On the other hand, the communication between the control pressure chamber and the low-pressure fuel passage is established by the valve member being electrically driven by the first valve seat and the second valve seat.
This is done by leaving the valve seat. like this,
Even when the two-way valve type valve device is applied to the fuel injection device, the same effect as that of the above-described claim 9 can be obtained. In addition, by adopting the configuration described in claims 19 to 21 to the valve device, the above-described claims 11 and 1 are respectively provided.
It is possible to obtain the same effects as those of 4 and 16.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) A fuel injection device for a diesel engine using a three-way valve as a valve device according to a first embodiment of the present invention is shown in FIG.

As shown in FIG. 2, the valve body 20 and the housing 21 are connected by a retaining nut 22. An injection hole 20 a is formed at the tip of the valve body 20. The injection hole valve member 25 is composed of a plurality of members including a needle valve member 26 and a control piston 27, and opens and closes the injection hole 20a by reciprocating. The valve body 20 is provided with a needle valve seat 20b on the upstream side of the injection hole.
The injection hole 20a is closed by the needle valve member 26 sitting on the needle valve seat 20b. The spring 28 urges the needle valve member 26 downward in FIG. 2, that is, in the injection hole closing direction. A control pressure chamber 60 is formed on the side of the control piston 27 opposite the injection hole. The pressure in the control pressure chamber 60 is applied to the injection hole valve member 25 in a direction to close the injection hole 20a.

The fuel supplied from a common rail (not shown) to the fuel chamber 62 around the injection hole valve member 25 through the high pressure fuel passage 61 is supplied to a gap formed between the injection hole valve member 25, the housing 21 and the valve body 20. And reaches the tip of the needle valve member 26. A chamfer is formed at a position where the injection hole valve member 25 except the control piston 27 slides with the housing 21 and the valve body 20 so that fuel can pass therethrough. The fuel supplied to the fuel chamber 62 passes through a fuel passage 27a formed in the control piston 27 and is supplied to the control pressure chamber 60.
Is also supplied. The high-pressure fuel passage 61 is branched into a passage 66, and the passage 66 communicates with a fuel inflow passage 64 of the three-way valve 30 described later.

As shown in FIG. 1, the three-way valve 30 has a first valve body 31 and a second valve body 35 as valve bodies. The first valve body 31 and the second valve body 35 are in close contact with the contact surface 31a and the contact surface 35a. The first valve body 31 and the second valve body 35 are positioned by fitting pins 38 into positioning holes 33 and 37 formed in both valve bodies.

First ball valve member 40 as first valve member
And the second ball valve member 41 as the second valve member
Valve chamber 3 formed by valve body 31 and second valve body 35
0a so as to be movable. The diameter and seat diameter of both ball valve members are equal. The two ball valve members move integrally due to the fuel pressure on the high pressure side and the force received from the piezoelectric element 51, but can move independently of each other. When the first ball valve member 40 is seated on the first valve seat 32, the fuel outflow passage 63 as the first passage is closed, and when the second ball valve member 41 is seated on the second valve seat 36, the second passage is formed. The fuel inflow passage 64 is closed.

The fuel outlet passage 63 formed in the first valve body 31 communicates with the low pressure chamber 67. The fuel inflow passage 64 formed in the second valve body 35 communicates with the passage 66. The valve chamber 30a formed in the second valve body 35
The fuel control passage 65 which opens to the side of is connected to the control pressure chamber 60.

The electric drive unit 50 has a piezoelectric element 51 as a drive source and a piston 52 which reciprocates as the piezoelectric element 51 expands and contracts. Electric power is supplied to the piezoelectric element 51 from a terminal 46 embedded in the connector 45. The disc spring 53 biases the piezoelectric element 51 in a direction away from the first ball valve member 40.

Next, a description will be given of a state in which the two valve bodies are displaced. The diameter Dv of the ball valve members 40 and 41 is 2 mm, the cone apex angle of the valve body accommodating both ball valve members is 90 °, and the lift amount Hv1 of both ball valve members is 20 μm.
And Conical apex angle of valve body and ball valve member 4
The diameters and lift amounts of 0 and 41 are not limited to the values described above.

FIG. 3 shows a state in which the first ball valve member 40 is seated on the first valve seat 32 and the second ball valve member 41 is seated on the second valve seat 36 in a state where both valve bodies are displaced. It shows the state where it is. As shown in FIG. 4, the distance between the contact surface 31a and the second ball valve member 41 in the lift direction is a, and the contact surface 35
Assuming that the distance between the valve body a and the first ball valve member 40 in the lift direction is b, when the positions of both valve bodies are not shifted as shown in FIG. 1, the lift amount Hv1 of both ball valve members is Hv1.
= A + b. The values of a and b may be any values as long as Hv1 = a + b is satisfied, and one of the ball valve members may be beyond the boundary of the contact surface. When the positions of the two valve bodies are not shifted, the two ball valve members are not fixed between the two valve bodies, and the fuel does not leak from between the contact surface 31a and the contact surface 35a.

Next, the positions of the two valve bodies are set at 4 along the contact surface.
Let us consider the case where the displacement is 0 μm. If both valve bodies are shifted by 40 μm along the contact surface, both ball valve members can be shifted by 40 μm in the direction along the contact surface while sitting on each valve seat. In FIG. 4, the displacement Ha of the two ball valve members along the contact surface is Ha = 40 μm. The distance Hv2 over which both ball valve members can move in the lift direction is Hv2 = H
v1 + 2x. Here, x = (Dv / 2) −y, y = ((Dv / 2) ² − (Ha
/ 2) ^{2) 1/2} Therefore, Hv2 = Hv1 + 2 (( Dv / 2) - ((Dv / 2) 2 - (Ha / 2) 2) 1/2) Hv2 = Hv1 + Dv- (Dv 2 -Ha 2) ^1/2 (1) In equation (1), Hv1 = 20 μm, Dv = 2 mm, Ha = 40
Substituting μm, Hv2 ≒ 20.4 μm, which is almost the same as the design value Hv1 = 20 μm. Therefore,
Even if the two valve bodies are displaced along the contact surface, the ball valve member is fixed between the valve bodies, thereby preventing malfunction. Further, since the ball valve member is fixed between the valve bodies, the contact surface of the valve body is prevented from separating, and the fuel is prevented from leaking from the gap. Also, since the valve member does not change its posture after sitting on the valve seat,
Wear of the valve member and the valve seat can be prevented.

Next, the operation of the fuel injection device 10 will be described. (1) When the piezoelectric element 51 is in a discharged state, the piezoelectric element 5
1 is in the position shown in FIG. 1 without stretching. The piston 52 is
The first ball valve member 40 is slightly separated from the first ball valve member 40 so as not to prevent the first ball valve member 40 from sitting on the first valve seat 32. When the piezoelectric element 51 is in a discharged state and the piezoelectric element 51 is not extended, the first ball valve member 40 is moved to the first ball valve member 40 by the force received from the pressure difference between the low-pressure fuel outflow passage 63 and the high-pressure fuel inflow passage 64. The second ball valve member 41 is seated on the valve seat 32 and is separated from the second valve seat 36. Therefore,
The fuel outflow passage 63 is closed, and the fuel inflow passage 64 communicates with the fuel control passage 65 on the control pressure chamber 60 side. Control pressure chamber 6 through fuel inflow passage 64 and fuel control passage 65
0 and the high-pressure fuel passage 66 communicate with each other, so that the fuel pressure in the control pressure chamber 60 is high. At this time, the fuel pressure in the control pressure chamber 60 and the spring
Since the force applied to the nozzle hole 5 in the injection hole closing direction is greater than the force applied to the injection hole valve member 25 from the fuel in the fuel chamber 62 in the injection hole opening direction, the needle valve member 26 is seated on the needle valve seat 20b and the injection hole 20a is closed. It is closed. Therefore, no fuel is injected from the injection hole 20a.

(2) When the piezoelectric element 51 is charged, the disc spring 5
3 against the biasing force of the first ball valve member 4
Stretch toward zero. Then, since the first ball valve member 40 is separated from the first valve seat 32 and the second ball valve member 41 is seated on the second valve seat 36, the fuel outflow passage 63 and the fuel control passage 65 communicate with each other, and the fuel The inflow passage 64 is closed. From the control pressure chamber 60 to the fuel control passage 65 and the fuel outflow passage 63
The fuel is discharged into the low pressure chamber 67 via the control valve 70, so that the fuel pressure in the control pressure chamber 60 decreases. The fuel discharged to the low-pressure chamber 67 is returned from the fuel passage 68 to the outside of the fuel injection device 10, for example, to a fuel tank. When the fuel pressure in the control pressure chamber 60 and the force that the injection hole valve member 25 receives in the injection hole closing direction from the spring 28 becomes smaller than the force that the injection hole valve member 25 receives from the fuel in the fuel chamber 62 in the injection hole opening direction, the needle The valve member 26 is separated from the needle valve seat 20b, and fuel is injected from the injection hole 20a.

(3) When the electric charge of the piezoelectric element 51 is released, the piezoelectric element 51 contracts. Then, the first ball valve member 40 and the second ball valve member 41 are pushed toward the first valve seat 32 by the fuel pressure in the fuel inflow passage 64, so that the fuel outflow passage 63 is closed and the fuel inflow passage 64 is closed. The fuel control passage 65 communicates with the fuel control passage 65. Then, the fuel pressure in the control pressure chamber 60 increases. When the force that the injection hole valve member 25 receives in the injection hole closing direction from the fuel pressure of the control pressure chamber 60 and the spring 28 becomes larger than the force that the injection hole valve member 25 receives from the fuel in the fuel chamber 62 in the injection hole opening direction, the needle Valve member 2
6 is seated on the needle valve seat 20b and closes the injection hole 20a. Therefore, fuel injection from the injection hole 20a is shut off.

As described above, by controlling the charging and discharging of the piezoelectric element 51, the two ball valve members reciprocate in the valve chamber 30a and the fuel pressure in the control pressure chamber 60 increases and decreases, so that the injection holes 20a are opened and closed. . Further, since the first ball valve member 40 and the second ball valve member 41 are formed in a spherical shape, and the seating surface of the seat to be seated is not a flat surface but a conical surface, when both valve members are seated on the valve seats respectively. Can be suppressed.

In the first embodiment, the seat diameters of the first ball valve member 40 and the second ball valve member 41 are the same, but the second ball valve member 41 closing the high pressure side fuel inflow passage 64 is used.
To close the fuel outlet passage 63 on the low pressure side.
It is preferable that the seat diameter of the ball valve member 40 is smaller than the seat diameter.

In FIG. 5, reference numeral 100 denotes a graph showing the relationship between the driving force (generation force) of the piezoelectric element 51 and the amount of displacement when the driving voltage applied to the piezoelectric element 51 is 200 V;
102 is a graph showing the relationship between the generated force and the displacement of the piezoelectric element 51 when the driving voltage applied to the piezoelectric element 51 is set to 150V. The amount of displacement indicated by points 101 and 103 is the second
This is the amount of displacement of the piezoelectric element 51 required for seating the second ball valve member 41 on the valve seat 36. First ball valve member 4
The displacement amount of the piezoelectric element 51 when 0 is separated from the first valve seat 32 is almost 0. The generated force indicated by the point 101 is the generated force of the piezoelectric element 51 required for the first ball valve member 40 to separate from the first valve seat 32 in the first embodiment.

As shown in FIG. 5, in general, a piezoelectric element generates a large force when the displacement is small when the driving voltage is constant, and
As the displacement increases, the generated force decreases. In the configuration of the three-way valve 30 shown in the first embodiment, the force required to separate the first ball valve member 40 from the first valve seat 32 is such that the pressure in the low-pressure side fuel outlet passage 63 is zero. , The product of the seat area of the first ball valve member 40 and the fuel pressure in the valve chamber 30a, that is, the high-pressure fuel passage 66. Also, the second valve seat 36
The force required to maintain the state where the second ball valve member 41 is seated is the product of the seat area of the second ball valve member 41 and the fuel pressure in the high-pressure fuel passage 66. Second valve seat 36
The amount of displacement of the piezoelectric element 51 when the second ball valve member 41 is kept seated is larger than the amount of displacement of the piezoelectric element 51 when the first ball valve member 40 is separated from the first valve seat 32. large. Therefore, judging from the relationship between the generated force of the piezoelectric element and the amount of displacement shown in FIG. 5, when the seat diameter when the second ball valve member 41 is seated on the second valve seat 36 is reduced, the generated force of the piezoelectric element 51 is reduced. Even if is small, the state where the second ball valve member 41 is seated on the second valve seat 36 can be maintained. For example, if the seat diameters of the first ball valve member 40 and the second ball valve member 41 are the same, the force generated at the point 101 is required to seat the second ball valve member 41 on the second valve seat 36. , 200V. On the other hand, if the seat diameter of the second ball valve member 41 is smaller than the seat diameter of the first ball valve member 40, the generated force required to seat the second ball valve member 41 on the second valve seat 36 is The force at point 103,
Can be smaller. The driving voltage at this time is 150
V. Even when the drive voltage is set to 150 V, the force generated by the piezoelectric element 51 when the displacement is near 0 exceeds the force required to separate the first ball valve member 40 from the first valve seat 32. Therefore, the drive voltage applied to the piezoelectric element 51 can be reduced by making the seat diameter of the second ball valve member 41 smaller than the seat diameter of the first ball valve member 40.

(Second Embodiment) FIG. 6 shows a second embodiment of the present invention.
Shown in The same reference numerals are given to the same components as those in the first embodiment, and the description is omitted. A second ball valve member 41 and a spring 72 as an urging member are provided in the second valve body 70.
Is housed. The spring 72 is connected to the second valve body 7.
0 is in contact with the spring seat 71 formed at
The second ball valve member 4 is moved away from the second valve seat
One is energizing. Even if the pressure difference between the low-pressure side fuel outflow passage 63 and the high-pressure side fuel inflow passage 64 is small, when the electric charge of the piezoelectric element 51 is released, the first ball valve member 40 is securely seated on the first valve seat 32. be able to.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention.
Shown in The same reference numerals are given to the same components as those in the first embodiment, and the description is omitted. The spring 77 as an urging member is provided between the first ball valve member 40 and the second ball valve member 41.
And abuts a spring seat 76 formed on the second valve body 75. The spring 77 urges the first ball valve member 40 toward the first valve seat 32. Since no spring seat is formed on the second ball valve member 41 side, it is not necessary to reduce the diameter of the fuel inflow passage 64.

(Fourth Embodiment) FIG. 8 shows a fourth embodiment of the present invention.
Shown in The same reference numerals are given to the same components as those in the first embodiment, and the description is omitted. Since the first valve member 80 and the second valve member 83 are formed in substantially the same shape, the description of the first valve member 80 also serves as the description of the second valve member 83. Reference numerals 80, 81, and 82 correspond to reference numerals 83, 84, and 85, respectively.

The first valve member 80 includes a valve body 81 and a sliding portion 82 formed in an outer periphery of the valve body 81 in an annular shape.
The end of the valve body 81 on the first valve seat 32 side is formed in a truncated conical shape whose diameter decreases toward the first valve seat 32. The sliding portion 82 is guided by the inner peripheral wall of the first valve body 31 and slides on the inner peripheral wall of the first valve body 31 according to the expansion and contraction of the piezoelectric element 51. A communication passage 82 for allowing fuel to communicate with the sliding portion 82
a are formed in plurality.

Since the first valve member 80 and the second valve member 83 abut on the planes 81a and 84a, even if the pressure difference between the low-pressure side fuel outflow passage 63 and the high-pressure side fuel inflow passage 64 is large. Thus, the surface pressure applied to the contact surfaces of the two valve members is reduced.
Therefore, damage to both valve members can be prevented.

(Fifth Embodiment) FIG. 9 shows a fifth embodiment of the present invention.
Shown in The same reference numerals are given to the same components as those in the first embodiment, and the description is omitted. The first valve member 92 includes a cylindrical valve body 93 and a sliding portion 94 formed in an annular shape on the outer periphery of the valve body 93. The sliding portion 94 is guided by the inner peripheral wall of the first valve body 90 and slides on the inner peripheral wall of the first valve body 90 according to the expansion and contraction of the piezoelectric element 51. The sliding portion 94 is provided with a plurality of communication passages 94a for communicating fuel.

The first valve seat 91 is formed in a flat shape.
Contact portion 93a of first valve member 92 seated on first valve seat 91
Is also formed in a planar shape, so that the first valve member 92
When seated on the valve seat 91, the surface pressure applied to the contact portion 93a and the first valve seat 91 can be reduced. Therefore, even if the pressure difference between the low pressure side fuel outflow passage 63 and the high pressure side fuel inflow passage 64 is large, the first valve member 92 and the first valve seat 91
Damage can be prevented.

(Sixth Embodiment) FIG. 1 shows a sixth embodiment of the present invention.
0 is shown. The same reference numerals are given to the same components as those in the first embodiment, and the description is omitted. The first valve member 100 and the hemispherical second valve member 101 are both formed in a hemispherical shape, and their respective flat portions 100a and 101a face each other.
It is housed in the valve chamber 30a. The first valve member 100 and the second
Since the contact portion with the valve member 101 is flat, the positional relationship between the two valve members is stabilized after the two valve members once sit on the valve seat. Therefore, it is possible to more effectively prevent the positions of the two valve bodies from being shifted from each other and increasing the amount of wear of the valve bodies and the valve members.

In the above-described first to sixth embodiments showing the embodiment of the present invention, two valve members are accommodated in a valve body composed of two valve bodies. Therefore, even if the positions of the valve bodies are shifted along the contact surfaces of each other, the valve members are shifted along the contact surfaces of the valve bodies, thereby enabling the movement of both valve members. This prevents the valve member from being fixed, so that the valve device can reliably switch the flow path even if the position of the valve body is displaced. Further, even if the position of the valve body shifts, the contact surfaces between the valve bodies do not separate, so that the fluid can be prevented from leaking from the gap. The effects of the above-described plurality of embodiments are effective when the lift amount of the valve member of the valve device is extremely small in the order of microns. In particular, it is particularly effective when a piezoelectric element having a large generated force but a small displacement is used as a drive source of the electric drive unit of the valve device.

(Seventh Embodiment) FIG. 1 shows a seventh embodiment of the present invention.
It is shown in FIG. The same reference numerals are given to the same components as those in the first embodiment, and the description is omitted. The fuel control passage 140 is the first
It is formed on the side of the valve body 31 so as to open to the valve seat 30a. The second valve seat 12 is attached to the end of the second valve body 120.
1 is formed in a planar shape. The valve member 130 is composed of a single member. The valve member 130 has a shape in which two flat surfaces 130a and 130b are formed by cutting off both ends of a sphere. The first contact portion 130c seated on the first valve seat 32 of the valve member 130 is formed on a spherical surface. Plane 13
A part of Oa closes an opening of the fuel inflow passage 64 with the valve chamber 30a. That is, a part of the flat surface 130a becomes the second contact portion.

Since the valve member is composed of one member, the behavior of the valve member is stable, and it is more effective to prevent the positions of both valve bodies from shifting and the amount of wear of the valve body and the valve member to increase. Can be prevented. Further, the end surface of the valve member 130 contacting the piston 52 is defined as a flat surface 130b.
The flat surface 52a has an end surface that abuts on the valve member 130, so that abrasion between the piston 52 and the valve member 130 can be prevented.

Further, the second valve seat 121 is formed in a planar shape, and the second contact portion seated on the second valve seat 121 is also formed in a planar shape. 121
The surface pressure applied to the second contact portion and the second valve seat 121 when the user is seated on the vehicle can be reduced. Therefore, even if the pressure difference between the low pressure side fuel outflow passage 63 and the high pressure side fuel inflow passage 64 is large, damage to the valve member 130 and the second valve seat 121 can be prevented.

(Eighth Embodiment) FIG. 12 shows a fuel injection system for a diesel engine using a valve device according to an eighth embodiment of the present invention. In this embodiment, a two-way valve is employed as a valve device. The same reference numerals are given to the same components as those in the first embodiment, and the description is omitted.

In the fuel injection device shown in FIG. 12, a high-pressure passage 66 branched from a high-pressure fuel passage 61 communicates directly with the control pressure chamber 60. That is, the high-pressure passage 66 is configured to communicate with the control pressure chamber 60 via the fuel inflow passage 64 as a first passage formed in the second valve body 120 of the two-way valve 300. Further, an in-orifice 301 is formed in the high-pressure passage 66, and an out-orifice 302 is formed in the fuel inflow passage 64.

FIG. 13 shows a two-way valve 300 as a valve device. Components substantially the same as those of the three-way valve shown in FIG. 11 are denoted by the same reference numerals. The main difference from the three-way valve shown in FIG. 11 is that the fuel control passage 140 is eliminated and the out orifice 302 is formed in the fuel inflow passage 64 as described above.

Next, control of the position of the valve member 130 by the electric drive unit 50 of the two-way valve 300 will be described. When the piezoelectric element 51 is in a discharging state, the piezoelectric element 51 is not extended and is at the position shown in FIG.
Is located at a position where the first contact portion 130c is seated. Accordingly, high-pressure fuel is supplied into the control pressure chamber 60 communicating with the high-pressure fuel passage 61, and the fuel pressure in the pressure chamber 60 is maintained at a high pressure.

When charging the piezoelectric element 51, the piezoelectric element 51 is charged at a predetermined charge amount at which the valve member 130 is at a predetermined position separated from both the first valve seat 32 and the second valve seat 121 in the compartment 30a.
Is extended, the control pressure chamber 60 communicates with the fuel outflow passage 63, and the fuel pressure in the pressure chamber 60 decreases.

Further, when the piezoelectric element 51 is extended with a higher charge from the state where the valve member 130 is at the predetermined position, the flat surface 130 a of the valve member 130 is seated on the second valve seat 121. Thereby, the high-pressure fuel in the high-pressure fuel passage 61 is supplied into the control pressure chamber 60 again, and the fuel pressure in the pressure chamber 60 becomes high.

In the eighth embodiment, by controlling the amount of expansion and contraction of the piezoelectric element 51 of the electric drive section 50 by the above-described stepwise charging control, the piezoelectric element 51 is seated on the first valve seat 32 or the second valve seat 120. The position of the valve member 130 is controlled to a position separated from both the first valve seat 32 and the second valve seat 33.

Next, the operation of the fuel injection device according to the eighth embodiment will be described. When the piezoelectric element 51 is in a discharged state,
The valve member 130 is seated on the first valve seat 32, and the high-pressure fuel from the high-pressure fuel passage 61 flows into the control pressure chamber 60 through the in-orifice 301.
The fuel pressure within 0 is high. At this time, the control pressure chamber 6
From the fuel pressure of 0 and the spring 28
Is received in the injection hole closing direction from the fuel in the fuel chamber 62 by the injection hole valve member 25 in the injection hole opening direction, so that the dollar valve member 26 is seated on the dollar valve seat 20b. The injection hole 20a is closed. Therefore, no fuel is injected from the injection hole 20a.

When the piezoelectric element 51 is charged with the above-mentioned predetermined charge, the valve member 130 becomes the first valve seat 32 and the second valve seat 12.
It is a position away from 0. Then, the control pressure chamber 60 communicates with the fuel outflow passage 63, and the fuel in the control pressure chamber 60 is discharged to the low pressure chamber 67 via the fuel outflow passage 63, and returned from the fuel passage 68 to an external fuel tank. Therefore,
Since the fuel pressure in the control pressure chamber 60 becomes low and the above-mentioned injection hole valve member 25 receives a small force in the injection hole closing direction,
The $ 21 valve member 26 is separated from the $ 21 valve seat 20b,
Fuel is injected from the injection hole 20a.

By further increasing the amount of charge to the piezoelectric element 51 from the above state, the valve member 130 moves downward and sits on the second valve seat 120. Then, since the communication between the control pressure chamber 60 and the fuel outflow passage 63 is cut off, the fuel pressure in the control pressure chamber 60 becomes high. Accordingly, the $ 21 valve member 26 is seated on the $ 21 valve seat 20b and
a, and the fuel injection from the injection hole 20a is stopped.

When the next fuel injection is executed from the state in which the valve member 130 is seated on the second valve seat 120, the electric charge of the piezoelectric element 51 is discharged and discharged to the predetermined charge amount.
Then, the piezoelectric element 51 contracts, and the valve member 130 is located at a position separated from the first valve seat 32 and the second valve seat 120, so that the fuel pressure in the pressure control chamber 60 decreases as described above. Therefore, the twenty-first valve member 26 is connected to the twenty-first valve seat 20b.
And the fuel is injected from the injection hole 20a.

Next, the piezoelectric element 51 is further discharged, and the valve member 130 is seated on the first valve seat 32. Thereby, the communication between the control pressure chamber 60 and the fuel outflow passage 63 is cut off,
When the fuel pressure in the control pressure chamber 60 becomes high, the dollar valve member 26 sits on the dollar valve seat 20b, closes the injection hole 20a, and the fuel injection from the injection hole 20a stops.

As described above, by controlling the amount of charge to the piezoelectric element 51 stepwise, the valve member 130 moves downward from the state of sitting on the first valve seat 32, and After seating on the valve member, the valve member 130 moves upward until it is seated again on the first valve seat 32, so that two fuel injections can be performed by one reciprocating movement of the valve member 130.

As in the eighth embodiment, in a fuel injection device having a two-way valve for controlling the amount of movement of a valve member between two valve seats in a stepwise manner, a valve member 130 shown in FIG. 13 is employed. Thereby, the same effect as in the seventh embodiment can be obtained. In this embodiment, the valve device shown in the seventh embodiment (FIG. 11) has been described as the structure of the two-way valve, but the valve device structure shown in the first to sixth embodiments has been described. May be applied.

In the above embodiments, the force generated by the piezoelectric element 51 is directly applied to the first ball valve member via the piston 52. In this case, the lift amount of the first ball valve member is substantially equal to the displacement amount of the piezoelectric element. On the other hand, when the lift amount of the first ball valve member is larger than the displacement amount of the piezoelectric element, a fuel chamber is provided between the piezoelectric element and the first ball valve member, and the fuel element on the piezoelectric element side facing the fuel chamber is provided. By making the pressure receiving area larger than the pressure receiving area on the first ball valve member side,
It is also possible to convert a small displacement of the piezoelectric element into a large displacement and apply it to the first ball valve member. In the above embodiments, the piezoelectric element is used as the drive source of the electric drive unit, but a magnetostrictive element may be used as the drive source. In the above embodiments, the valve device of the present invention is applied to a fuel injection device for a diesel engine. However, the present invention is not limited to the fuel injection device, but may be applied to any application as long as the valve device is used.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a three-way valve as a valve device used in a fuel injection device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the fuel injection device of the first embodiment.

FIG. 3 is a sectional view showing a state in which the position of a valve body is shifted in the three-way valve of the first embodiment.

FIG. 4 is an explanatory view showing a state in which the position of a ball valve member is shifted in the three-way valve of the first embodiment.

FIG. 5 is a characteristic diagram showing a relationship between a generated force and a displacement of a piezoelectric element with respect to a drive voltage in the three-way valve of the first embodiment.

FIG. 6 is a sectional view showing a three-way valve as a valve device according to a second embodiment of the present invention.

FIG. 7 is a sectional view showing a three-way valve as a valve device according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a three-way valve as a valve device according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing a three-way valve as a valve device according to a fifth embodiment of the present invention.

FIG. 10 is a sectional view showing a three-way valve as a valve device according to a sixth embodiment of the present invention, showing a state where the position of a valve body is shifted.

FIG. 11 is a sectional view showing a three-way valve as a valve device according to a seventh embodiment of the present invention, showing a state where the position of a valve body is shifted.

FIG. 12 is a sectional view showing a fuel injection device according to an eighth embodiment of the present invention.

FIG. 13 is a sectional view showing a three-way valve as a valve device used in a fuel injection device according to an eighth embodiment of the present invention, showing a state where the position of a valve body is shifted.

FIG. 14 is a sectional view showing a conventional three-way valve.

FIG. 15 is a cross-sectional view showing a state where the position of a valve body is shifted in a conventional valve device.

[Explanation of symbols]

 Reference Signs List 10 fuel injection device 20a injection hole 25 injection hole valve member 26 needle valve member 30 three-way valve 31 first valve body 32 first valve seat 35 second valve body 36 second valve seat 38 pin 40 first ball valve member (first Valve member) 41 second ball valve member (second valve member) 50 electric drive unit 51 piezoelectric element (electric drive unit) 52 piston (electric drive unit) 60 control pressure chamber 63 fuel outflow passage (first passage) 64 fuel inflow Passage (second passage) 65 Fuel control passage (third passage) 70, 75 Second valve body 72, 77 Spring (biasing member) 80, 92 First valve member 83 Second valve member 90 First valve body 100 First 1 valve member 101 second valve member 120 second valve body 121 second valve seat 130 valve member 130a plane (second contact portion) 300 three-way valve

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02M 51/00 F02M 51/00 FE 61/20 61/20 N // F16K 27/00 F16K 27/00 D (72) Inventor Toshihiko Inoka 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation (72) Inventor Toshio Kondo 1-1-1, Showa-cho, Kariya-shi, Aichi F term (Reference) 3G066 AA07 AB02 AD12 BA19 BA35 CC06T CC08T CC14 CC21 CC64T CC67 CC68U CC70 CD30 CE27 CE34 3H051 AA01 AA07 BB10 CC11 FF15

Claims (21)

[Claims] A first valve seat and a second valve seat which are disposed at positions facing each other and on which the valve member can be seated; And the valve member is the first
A valve body that closes a first passage when seated on a valve seat and closes a second passage when the valve member seats on the second valve seat, wherein the valve body is the first valve A first valve body having a seat; and a second valve body having the second valve seat, wherein the valve member is seated on a first contact portion capable of sitting on the first valve seat and on the second valve seat. A valve device comprising: a possible second contact portion; and a relative position of the two contact portions is variable according to a relative position of the two valve seats. 2. The valve member according to claim 1, wherein the first valve member is seated on the first valve seat, and a second valve member is seated on the second valve seat.
The valve device according to claim 1, further comprising a valve member, wherein the two valve members are movable independently of each other. 3. The valve device according to claim 2, wherein the first valve member and the second valve member are formed in a spherical shape. 4. The first valve member and the second valve member are formed in a hemispherical shape, and a planar outer wall of the first valve member and a planar outer wall of the second valve member face each other. The valve device according to claim 2, wherein the valve device is provided. 5. The apparatus according to claim 1, wherein the first passage is a fluid outflow passage, and the second passage is a fluid inflow passage, and includes an urging member for urging one of the contact portions toward the first valve seat. The valve device according to any one of claims 1 to 4, characterized in that: 6. The conical valve seat of the valve member, wherein one of the first and second valve seats is formed in a conical shape, and the other is formed in a planar shape. The valve device according to claim 1, wherein the end surface on the side of the valve member is formed on a spherical surface, and the end surface on the valve seat side of the valve member is formed in a planar shape. 7. The valve device according to claim 1, wherein the electric drive unit has a piezoelectric element that generates a driving force. 8. The electric drive unit includes a piston for transmitting a driving force to the valve member, the piston having an end portion in contact with the valve member formed in a planar shape. The valve device according to any one of claims 1 to 7, wherein an end portion abutting on the piston is formed in a planar shape. 9. An injection hole valve member for opening and closing an injection hole, a control pressure chamber provided on a side opposite to the injection hole of the injection hole valve member and applying a fuel pressure to the valve member in a direction of the injection hole; A valve device for selectively communicating the control pressure chamber with the low-pressure fuel passage, wherein when the control pressure chamber communicates with the high-pressure fuel passage by the valve device, the pressure in the control pressure chamber becomes high and the injection hole When the valve member shuts off the injection hole and the control pressure chamber communicates with the low-pressure fuel passage by the valve member, the pressure in the control pressure chamber becomes low and the injection hole valve member opens the injection hole. A fuel injection device that injects fuel into a cylinder of an internal combustion engine, wherein the valve device includes: a valve member; an electric drive unit that generates a driving force for moving the valve member; Members can be seated Having a first valve seat and second valve seat, said valve member said first
When seated on a valve seat, the low-pressure fuel passage is closed and the high-pressure fuel passage communicates with the control pressure chamber. When the valve member is seated on the second valve seat, the high-pressure fuel passage is closed and A valve body in which the low-pressure fuel passage communicates with the control pressure chamber; the valve body has a first valve body having the first valve seat and a second valve body having the second valve seat; The valve member has a first contact portion that can be seated on the first valve seat and a second contact portion that can be seated on the second valve seat, and the relative positions of the both contact portions are the two valves. A fuel injection device characterized by being variable according to a relative position of a seat. 10. The valve member has a first valve member that can be seated on the first valve seat, and a second valve member that can be seated on the second valve seat, and the two valve members are independent of each other. The fuel injection device according to claim 9, wherein the fuel injection device is movable. 11. The fuel injection device according to claim 10, wherein the first valve member and the second valve member are formed in a spherical shape. 12. The first valve member and the second valve member are formed in a hemispherical shape, and a planar outer wall of the first valve member and a planar outer wall of the second valve member face each other. The fuel injection device according to claim 10 or 11, wherein 13. The first passage is a fluid outflow passage,
The said 2nd path | pass is a fluid inflow path, Comprising: The urging member which urges | biases one of the said both contact parts to the said 1st valve seat is provided. Fuel injection device. 14. The conical valve seat of the valve member, wherein one of the first and second valve seats is formed in a conical shape, and the other valve seat is formed in a planar shape. 10. The fuel injection device according to claim 9, wherein the end surface on the side of the valve member is formed on a spherical surface, and the end surface on the valve seat side of the valve member is formed in a planar shape. 15. The fuel injection device according to claim 9, wherein the electric drive unit has a piezoelectric element that generates a driving force. 16. The electric drive section includes a piston for transmitting a driving force to the valve member, the piston having an end portion abutting on the valve member formed in a planar shape, wherein the valve member includes the piston. The fuel injection device according to any one of claims 9 to 15, wherein an end portion abutting on the piston is formed in a planar shape. 17. The apparatus according to claim 17, wherein the electric drive section has a piezoelectric element for generating a driving force, and a sheet diameter of the second contact section is smaller than a sheet diameter of the first contact section. 9 ~
17. The fuel injection device according to claim 16. 18. An injection hole valve member that opens and closes an injection hole, and is provided on the opposite injection hole side of the injection hole valve member, communicates with a high-pressure fuel passage, and controls fuel pressure to the valve member in the injection hole direction. A pressure chamber, a valve device that communicates or shuts off the control pressure chamber, and a low-pressure fuel passage that allows fuel in the control pressure chamber to escape to the low-pressure side, and the control pressure chamber and the low-pressure fuel passage are provided by the valve device. When the communication is interrupted, the control pressure chamber becomes high pressure, the injection hole valve member shuts off the injection hole, and when the control pressure chamber communicates with the low pressure fuel passage by the valve member, the control is performed. In a fuel injection device that injects fuel into a cylinder of an internal combustion engine by a low pressure in a pressure chamber and the injection hole valve member opens the injection hole, the valve device moves the valve member and the valve member Electric drive that generates the driving force A moving part; a first valve seat and a second valve seat which are arranged at positions facing each other and on which the valve member can be seated, wherein the valve member is electrically driven by the first or second valve seat. The low-pressure fuel passage is closed when seated, and the control pressure chamber and the low-pressure fuel passage are closed when the valve member is separated from the first valve seat and the second valve seat by the electric drive unit. A first valve body having the first valve seat and a second valve body having the second valve seat, wherein the valve member is connected to the first valve seat. It has a first contact portion that can be seated and a second contact portion that can be seated on the second valve seat, and the relative position of the two contact portions is variable according to the relative position of the two valve seats. A fuel injection device characterized by the above-mentioned. 19. The fuel injection device according to claim 18, wherein the first valve member and the second valve member are formed in a spherical shape. 20. One of the first valve seat and the second valve seat is formed in a conical shape, and the other valve seat is formed in a planar shape, and the conical valve seat of the valve member is formed. 19. The fuel injection device according to claim 18, wherein an end surface on the side of the valve member is formed on a spherical surface, and an end surface of the valve member on the valve seat side is formed in a planar shape. 21. The electric drive section, comprising: a piston for transmitting a driving force to the valve member, the piston having an end formed in a planar shape in contact with the valve member; 21. The fuel injection device according to claim 18, wherein an end portion abutting on the piston is formed in a planar shape.