JPH08177675A - Solenoid valve - Google Patents

Abstract

PURPOSE: To attain facilitation of working while realizing stable action of a valve body. CONSTITUTION: A solenoid spill valve 25 is arranged in the halfway of spill passages 24a, 24b of a fuel injection pump 1. In the solenoid spill valve 25, a valve body slide hole, high pressure fuel passage, high pressure chamber and a low pressure fuel passage are formed in a valve housing 27. A valve body 28 is slidably inserted to the valve body slide hole. In the high pressure chamber, high pressure fuel is introduced in a direction orthogonal to a direction of moving the valve body 28. A valve guide 29, brought into slide contact with an internal diametric part of this valve body 28, is inserted to its lower opening. A pressure receiving area of the valve body 28 in the downstream of a valve is regulated by the valve guide 29, so as to reduce force received to the valve body 28 by a pressure in the downstream of the valve. Two sliding surfaces, brought into slide contact with the valve housing 27 and the valve guide 29, are respectively formed in external/internal diametric parts of the valve body 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve provided in the middle of a fluid passage that connects a high pressure fluid chamber and a low pressure fluid chamber.

[0002]

2. Description of the Related Art This type of solenoid valve is provided in the middle of a fluid passage connecting a high-pressure fluid chamber and a low-pressure fluid chamber, and permits the fluid to flow from the high-pressure fluid chamber to the low-pressure fluid chamber as the valve opens. The fluid flow is prohibited with the valve closing operation. Such an electromagnetic valve is embodied as an electromagnetic fuel spill valve attached to a fuel injection pump of a diesel engine, for example.

Further, in this type of solenoid valve, various techniques have been proposed for enabling the valve body to operate with a stable behavior without being affected by the fluid pressure. For example, JP
The solenoid valve disclosed in Japanese Patent Laid-Open No. 1-72867 uses a structure in which a high pressure fluid passage is provided in a direction orthogonal to the moving direction of the valve body and the high pressure fluid is taken in from the passage. That is, the high-pressure fluid is guided in a direction orthogonal to the moving direction of the valve element to reduce the influence of the high-pressure fluid on the operation of the valve element, thereby stabilizing the operation of the valve element.

However, the above solenoid valve causes a new problem that the operation of the valve body becomes unstable due to the influence of the fluid pressure from the low pressure fluid chamber side. That is, when the solenoid valve is opened to allow the high-pressure fluid to flow into the low-pressure fluid chamber, the pressure of the low-pressure fluid chamber temporarily rises due to the inflow of the high-pressure fluid, and the pressure change causes pressure pulsation in the low-pressure fluid chamber. Occurs. Then, the fluid pressure including this pulsating component adversely affects the operation of the valve element. Therefore, as a technique for solving this problem, in the solenoid valve disclosed in JP-A-1-113570, in addition to the configuration disclosed in JP-A-61-272867,
The low-pressure fluid passage on the downstream side of the valve body is provided in a direction orthogonal to the moving direction of the valve body. In this solenoid valve, the influence of the fluid pressure on the high pressure side on the valve body operation is suppressed,
The influence of the fluid pressure on the low pressure side on the valve body operation is suppressed.

[0005]

However, the solenoid valve disclosed in Japanese Patent Laid-Open No. 61-72867 has the following problems. That is, in the solenoid valve, in order to form the high-pressure fluid passage and the low-pressure fluid passage in the direction orthogonal to the moving direction of the valve body, a plurality of valve members are provided between the valve body and the housing member slidably arranged therein. A sliding surface is formed. Then, although high machining accuracy is required for these sliding surfaces in order to realize a high-pressure seal, it is actually difficult to machine each sliding surface coaxially with high accuracy. It was an obstacle.

The present invention has been made in view of the above problems, and an object thereof is to provide a solenoid valve which can realize a stable operation of a valve body and can be easily processed. To do.

[0007]

In order to achieve the above object, a solenoid valve according to a first aspect of the present invention is provided in the middle of a fluid passage which connects a high pressure fluid chamber and a low pressure fluid chamber, and is connected to an electromagnetic drive member. A solenoid valve that opens or closes in accordance with the energization of a valve body sliding hole, a high pressure fluid passage extending from the high pressure fluid chamber and opening in a direction orthogonal to the valve body sliding hole, and the low pressure fluid chamber. A housing member having a low-pressure fluid passage extending from the valve body and opening into the valve body sliding hole; and two sliding surfaces, one sliding surface of which is in sliding contact with the valve body sliding hole of the housing member. A valve body disposed on the housing member; and a valve body guide member arranged to be in sliding contact with the other sliding surface of the valve body and to restrict the pressure receiving area of the valve body on the low pressure fluid passage side. That is the gist.

The electromagnetic valve according to claim 2 is used as an electromagnetic fuel spill valve provided in a fuel injection pump of a diesel engine.

[0009]

In the solenoid valve according to the first aspect of the present invention, when the valve body is moved by energizing the electromagnetic drive member, the fluid passage that connects the high pressure fluid chamber and the low pressure fluid chamber is opened or closed. At this time, since the high-pressure fluid is guided from the direction orthogonal to the moving direction of the valve body, the valve body operates without being affected by the high-pressure fluid, and the influence does not cause the valve body to exhibit unstable behavior. Further, since the valve body guide member regulates the receiving area of the valve body on the low-pressure fluid passage side, the force received by the valve body from the fluid pressure in the low-pressure fluid chamber is reduced, and the valve body is not affected by the fluid pressure in the low-pressure fluid chamber. Stable behavior is also avoided.

Further, in this structure, the two sliding surfaces of the valve body slide with respect to the two members of the housing member and the valve body guide member. Therefore, even if a high-pressure seal is required for these sliding surfaces, the processing can be easily performed. In other words, according to this configuration, since each sliding surface is configured by a different combination (valve element and housing member, valve element and valve element guide member), individual machining accuracy is easily satisfied, and as a solenoid valve, The accuracy requirement of is easily realized.

According to the solenoid valve of the second aspect, a stable fuel spill operation is realized in the fuel injection pump of the diesel engine.

[0012]

【Example】

(First Embodiment) A first embodiment in which the electromagnetic valve of the present invention is embodied as an electromagnetic fuel spill valve of a diesel engine fuel injection pump will be described below with reference to the drawings.

FIG. 1 shows a schematic structure of a fuel injection control device using a face cam type fuel injection pump. Note that, in the fuel injection pump 1 of FIG. 1, only essential parts are shown, and the configuration of a vane feed pump or the like which should be on the left side of the drawing is omitted. In FIG. 1, a drive shaft 3 is arranged in a pump housing 2 of a fuel injection pump 1, and a pulsar 4 having a plurality of teeth on its outer peripheral surface is attached to the drive shaft 3. When the drive shaft 3 rotates in synchronization with the crankshaft (not shown) of the diesel engine, a feed pump (not shown) rotates and fuel is supplied to the fuel chamber (low pressure fluid chamber) 5. The pressure inside the fuel chamber 5 is relatively low (for example, 10 k
g / cm ² ).

A cam plate 6 is connected to the right end of the drive shaft 3 in the figure via a coupling (not shown). One side of the cam plate 6 (left side of the figure)
Is provided with the same number of face cams 6a as the number of cylinders of the diesel engine. A roller ring 7 is arranged between the pulsar 4 and the cam plate 6, and the roller ring 7
A plurality of cam rollers 8 facing the face cam 6a of the cam plate 6 are attached to the.

A head portion 2a is provided on the right side of the pump housing 2 in the drawing, and a cylinder 10 is provided in the head portion 2a. A plunger hole 11 is formed in the cylinder 10. A plunger 12 is slidably arranged in the plunger hole 11. The plunger 12 is supported by the cam plate 6 so as to be integrally rotatable. The cam plate 6 is constantly urged and engaged with the cam roller 8 by the plunger spring 13. Therefore, the cam plate 6 and the plunger 12 rotate as the drive shaft 3 rotates, and the face cam 6a
And the cam roller 8 engage with each other to reciprocate in the left-right direction in the drawing.

A pump chamber (high pressure fluid chamber) 14 is formed by the cylinder 10 and the end surface of the plunger 12, and the suction groove 1 for the number of cylinders is formed on the peripheral surface near the end of the plunger 12.
5 is formed. When one of the suction grooves 15 communicates with the suction passage 16 provided in the cylinder 10 and the head portion 2a as the plunger 12 rotates, fuel is sucked from the fuel chamber 5 into the pump chamber 14. Also, the plunger 12
Is moved to the right in the figure, the fuel sucked into the pump chamber 14 is pressurized, and the fuel is communicated with the communication passage 17 and the distribution port 1.
It is pressure-fed to the injection passage 19 through 8. Then, the fuel is fed to the fuel injection nozzle 21 via the delivery valve 20 and injected from the nozzle 21 into the combustion chamber of the engine.

On the other hand, the fuel chamber 5 in the pump housing 2 is provided with a rotation speed sensor 22 which is attached integrally with the roller ring 7. The rotation speed sensor 22 is composed of an electromagnetic pickup coil and detects passage of teeth provided on the outer peripheral surface of the pulsar 4. That is, the rotation speed sensor 22 outputs a reference timing signal at a constant timing with respect to the plunger lift.

Further, the head portion 2a of the pump housing 2
Spill passages (fluid passages) 24a, 24b that connect the fuel chamber 5 and the pump chamber 14 to each other are formed in the spill passages 24a, 24b.
An electromagnetic spill valve) 25 is arranged. For convenience,
In the following description, 24a will be referred to as a high pressure side spill passage and 24b will be referred to as a low pressure side spill passage.

FIG. 2 is a sectional view showing the structure of the electromagnetic spill valve 25 in detail. In the electromagnetic spill valve 25 of FIG. 2, a casing 26 made of a non-magnetic material is screwed to the head portion 2b of the pump housing 2, and a valve housing 27 as a housing member is provided below the casing 26.
Is assembled. The valve housing 27 is formed with a valve body sliding hole 27a extending in the vertical direction in the drawing, and the valve body sliding hole 27a has a columnar shape and a valve body 28 that opens downward in the drawing slides. It is inserted as possible.

A high pressure fuel passage 27b communicating with the high pressure side spill passage 24a is formed in the valve housing 27, and a high pressure chamber 27c surrounding the valve body 28 in an annular shape is communicated with the high pressure fuel passage 27b. . This high pressure chamber 27
c introduces high-pressure fuel in a direction orthogonal to the moving direction of the valve body 28 (the vertical direction in the figure). Further, the valve housing 27 has a low pressure fuel passage 27d communicating with the low pressure side spill passage 24b. In this embodiment, the high pressure fuel passage 27b and the high pressure chamber 27c form a high pressure fluid passage, and the low pressure fuel passage 27d forms a low pressure fluid passage.

A tapered contact portion 28a is formed at the lower end of the valve body 28, and a valve seat 27e is formed in the valve housing 27 facing the contact portion 28a. Here, as shown in FIG. 3, the taper angle θ1 formed by the contact portion 28a of the valve body 28 is determined by the valve seat 27e of the valve housing 27.
Is set to be larger than the taper angle θ2 formed (θ1> θ2). Therefore, when the valve body 28 moves downward in the drawing, the uppermost portion of the contact portion 28a contacts the valve seat 27e as shown in FIG. That is, the valve closed state (see FIG.
In the state shown in (1), the high-pressure fuel acts only on the side surface of the valve element 28 extending in the vertical direction and does not act on the moving direction of the valve element 28.

Further, in FIG. 2, a valve guide 29 as a valve body guide member, which is in sliding contact with the inner diameter portion of the valve body 28, is inserted from below in the valve body 28. A compression coil spring 30 is arranged in the hollow portion of the valve body 28, and the compression coil spring 30 always urges the valve body 28 upward in the drawing. Similarly, the compression coil spring 30
As a result, the valve guide 29 is biased toward the pump housing 2, and the valve guide 29 is held in the fixed position in the figure. In this embodiment, the outer diameter portion and the inner diameter portion of the valve body 28 form two sliding surfaces.

On the other hand, an electromagnet 31 is provided above the casing 26.
And a rod 33 extending in the vertical direction in the figure is arranged at the center of the electromagnet 31. The rod 33 is supported by a bush 34. The lower end of the rod 33 is in contact with the upper surface of the valve body 28, and the armature 35 is attached to the upper end of the rod 33. Casing 2
A cap member 36 made of a non-magnetic material is caulked on the upper end of the member 6. A stopper 37 for restricting the movable position of the armature 35 is attached to the cap member 36, and an energization signal from a drive circuit 51 (see FIG. 1) described later is input to the coil 32 constituting the electromagnet 31. A terminal 38 is attached. In this embodiment, the electromagnet 31, the rod 33 and the armature 35 constitute an electromagnetic drive member.

Therefore, in the electromagnetic spill valve 25 having the above structure, the valve body 28 is held at the valve opening position (the position shown in FIG. 2) by the biasing force of the compression coil spring 30 when the electromagnet 31 is not energized. In this case, the contact portion 28a and the valve seat 27e
And the high pressure fuel passage 27b of the valve housing 27
And the low-pressure fuel passage 27d are always communicated with each other. On the other hand, when the electromagnet 31 is energized, the armature 3 is applied to the electromagnet 31.
5 is attracted, and the valve body 28 moves in the valve closing direction (downward direction in the figure) against the biasing force of the compression coil spring 30. As a result, the contact portion 28a and the valve seat 27e come into contact with each other, and the fuel passages (high-pressure fuel passage 27b and low-pressure fuel passage 27d) are closed.

The spring chamber 28b and the spaces 40 and 41 in the valve body 28 are communicated by the communication passages 28c, 33a and 42 provided in the valve body 28, the rod 33 and the electromagnet 31, respectively, and the respective spaces are the same. It is kept under pressure. Space 40
Communicate with the low-pressure fuel passage 27d through the communication passage 43.

On the other hand, in FIG. 1, an electronic control unit (hereinafter referred to as ECU) 50 includes a CPU (central processing unit),
It is composed of a microcomputer including various memories and input / output circuits. The ECU 50 has a rotation speed sensor 2
An accelerator opening signal, a water temperature signal, etc. are input in addition to the input signals from the ECU 2, and the ECU 50 operates the engine based on these input signals (engine speed, accelerator opening,
Cooling water temperature, etc.) is detected. In addition, the ECU 50 controls the fuel injection amount according to the operating state of the engine,
A drive pulse signal for opening and closing the electromagnetic spill valve 25 is generated at a predetermined crank angle position, and the drive circuit 51 outputs the signal.
Output to. Then, the drive circuit 51 responds to the drive pulse signal from the ECU 50 by the electromagnet 31 of the electromagnetic spill valve 25.
Energize and de-energize.

Next, the operation of the fuel injection control device of this embodiment will be described with reference to the timing chart of FIG. When the drive shaft 3 shown in FIG. 1 rotates due to the operation of the engine, the plunger 12 rotates with the rotation. When the intake groove 15 at the tip of the plunger 12 and the intake passage 16 of the cylinder 10 communicate with each other by the rotation of the plunger 12, the fuel in the fuel chamber 5 passes through the intake groove 15 and the communication passage inside the pump chamber 14 and the plunger 12. Inhaled to 17. After the fuel is sucked, the suction passage 16 is closed as the plunger 12 rotates. At this time, the face cam 6a of the cam plate 6 is rotated by the roller 8
When you get on the top, the amount of cam lift increases (time t1 in FIG. 5),
With this increase, the plunger 12 moves to the right in FIG.

Then, a predetermined valve drive timing (time t
2), the valve drive pulse (valve closing signal) is sent to the ECU 50.
And the electromagnet 31 of the electromagnetic spill valve 25 is energized. At this time, the valve body 28 starts to lift at a timing (time t3) slightly delayed from the output of the valve drive pulse,
The valve body 28 moves against the biasing force of the compression coil spring 30 to a position where the contact portion 28a and the valve seat 27e of the valve housing 27 contact. That is, the valve body 28 moves from the valve opening position to the valve closing position, and the fuel passages 27b and 27d of the valve housing 27 are closed.

The fuel pressure in the pump chamber 14 rises due to the closing operation of the electromagnetic spill valve 25. At this time, the distribution port 18 is opened to one injection passage 19,
The fuel highly compressed in the pump chamber 14 is the distribution port 1
It is pressure-fed to the fuel injection nozzle 21 through 8, the injection passage 19, and the delivery valve 20. At the time of this valve closing, the high-pressure fuel acts on the valve body 28 from a direction orthogonal to the moving direction of the valve body 28, so the valve body 28 is closed without being affected by the high-pressure fuel and is opened by the influence of the high-pressure fuel. There is nothing to do.

After that, the time t4 when the desired injection amount is obtained.
Then, the valve drive pulse is turned off, and the electromagnet 31 of the electromagnetic spill valve 25 is de-energized. Therefore, the compression coil spring 3
The urging force of 0 moves the valve body 28 upward in FIG.

The fuel passages 27b and 27d of the valve housing 27 are opened as the valve body 28 opens.
The high-pressure fuel in the pump chamber 14 flows into the gap between the contact portion 28a of the valve body 28 and the valve seat 27e of the valve housing 27. That is, the high-pressure fuel is spilled into the fuel chamber 5 through the spill passages 24a and 24b. Then, the pump room 14
The electromagnet 31 is energized every time fuel is pumped from
The above operation is repeated.

Further, in the above operation, at time t5 immediately after the opening of the electromagnetic spill valve 25, the pressure on the downstream side of the valve body 28 (referred to as the valve downstream side pressure) temporarily becomes high, and the valve changes due to this pressure change. Downstream pressure pulsates. More specifically, the valve downstream side pressure is normally maintained at, for example, 10 kg / cm ² , but when the valve is opened, about 500 kg / cm ² of fuel flows into the valve downstream side from the high pressure passage 27c, and 5
It rises to 0 kg / cm ² . Due to the increase in the pressure, the pressure on the valve downstream side pulsates in the range of 10 ± 10 kg / cm ² , and the pulsation of this pressure exerts an unstable force on the valve body 28.

However, in this structure, the influence on the pulsation of the valve downstream side pressure can be minimized.
That is, the valve guide 29 is inserted into the valve body 28 from below, and the area where the end portion of the valve body 28 is exposed to the valve downstream side (pressure receiving area for the valve downstream side pressure) is wholly exposed. It is greatly reduced compared to the case. In this case, the force that the valve body 28 receives in the moving direction due to the valve downstream side pressure depends on the difference between the inner and outer diameters of the valve body 28, and the force that the valve body 28 receives due to the reduction in size is not affected by the pressure pulsation. It can be kept within the range. In this way, the influence of the valve downstream side pressure on the valve closing operation of the valve body 28 is almost eliminated, and the valve closing response is maintained.

As described above, in the present configuration, the factor that makes the behavior of the valve body 28 unstable during valve opening operation or valve closing operation is eliminated, and stable valve opening or closing operation can be realized. it can.

Further, in this structure, the two sliding surfaces of the valve body 28 slide on the two members of the valve housing 27 and the valve guide 29. Therefore, even if a high-pressure seal is required for these sliding surfaces, the processing can be easily performed.
That is, according to this configuration, since each sliding surface is configured by a different combination (valve element 28 and valve housing 27, valve element 28 and valve guide 29), the individual processing accuracy is easily satisfied, and the electromagnetic accuracy is improved. The accuracy requirement of the spill valve 25 can be easily realized.

(Second Embodiment) Next, the structure of the electromagnetic spill valve 25 in the second embodiment will be described focusing on the differences from the first embodiment. FIG. 6 shows the structure of the main part of the electromagnetic spill valve 25 in the second embodiment.

In FIG. 6, a valve housing 60 as a housing member is provided with a valve body sliding hole 60a, a high pressure fuel passage 60b, a high pressure chamber 60c, a low pressure fuel passage 60d and a valve seat 60e. In the second embodiment, the high pressure fuel passage 60b and the high pressure chamber 60c form a high pressure fluid passage, and the low pressure fuel passage 60d forms a low pressure fluid passage. The valve body 61 is slidably inserted into the valve body sliding hole 60a of the valve housing 60. The valve body 61 has a tapered contact portion 61a facing the valve seat 60e.
And a small diameter portion 61b is formed below the contact portion 61a.
Are formed. The valve body 61 corresponds to the valve body 28 of FIG. 1 in the first embodiment, and the armature 35 is connected to the upper end of the valve body 61 via the rod 33 of FIG. Further, the valve body 61 is a compression coil spring 62.
Is urged in the upper direction of the drawing, that is, in the valve opening direction.

Further, a valve guide 63 as a valve body guide member is provided in the valve housing 60 in a loosely fitted state. The valve guide 63 has an annular shape and is in sliding contact with the second sliding portion 61c of the valve body 61. The contact surface between the lower end surface of the valve guide 63 and the head portion 2a of the pump housing 2 is a flat ground surface capable of high-pressure sealing. Therefore, the spill fuel flowing from the high pressure chamber 60c into the space on the low pressure side (65 in the figure) is not allowed to flow into the valve housing 6
0 penetrates into the gap between the valve guide 63 (66 in the drawing), but does not penetrate into the space below the valve body 61 (64 in the drawing). For example, an O-ring (not shown) is arranged on the contact surface, or a compression coil spring (not shown) is arranged on the upper surface of the valve guide 63 so that the valve guide 63 is always pressed downward. May be. In this second embodiment, two sliding surfaces are formed on the outer diameter portion of the valve body 61, and they are in sliding contact with the valve housing 60 and the valve guide 63, respectively.

In the second embodiment as well, similar to the construction of the first embodiment, the valve body 61 when the valve is opened or closed.
Stable operation can be realized. Further, the processing accuracy on each sliding surface may be combined by pairing the processing accuracy, and the processing can be easily performed.

The present invention can be embodied as follows in addition to the above embodiment. In the above embodiment, the electromagnetic valve of the present invention is embodied as the electromagnetic spill valve of the face cam type fuel injection pump, but this may be changed. For example,
The electromagnetic spill valve may be embodied in an inner cam type fuel injection pump.

[0041]

According to the invention described in claims 1 and 2, the excellent effect that the easiness of processing can be achieved while realizing the stable operation of the valve body is exhibited.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a fuel injection control device in a first embodiment.

FIG. 2 is a sectional view showing the structure of an electromagnetic spill valve according to the first embodiment.

FIG. 3 is a partial cross-sectional view showing an enlarged configuration of a valve seat of a valve housing and a contact portion of a valve body.

FIG. 4 is a partial cross-sectional view showing an enlarged configuration of a valve seat of a valve housing and a contact portion of a valve body.

FIG. 5 is a timing chart for explaining the operation of the fuel injection control device.

FIG. 6 is a partial sectional view showing the structure of an electromagnetic spill valve according to a second embodiment.

[Explanation of symbols]

24a ... High pressure side spill passage as fluid passage, 24b ...
Low pressure side spill passage as fluid passage, 25 ... Electromagnetic fuel spill valve, 27 ... Valve housing as housing member, 27a ... Valve body sliding hole, 27b ... High pressure fuel passage as high pressure fluid passage, 27c ... High pressure fluid passage High-pressure chamber as a reference, 27d ... Low-pressure fuel passage as a low-pressure fluid passage, 28
... Valve element, 29 ... Valve guide as valve element guide member,
31 ... Electromagnet as electromagnetic driving member, 33 ... Rod as electromagnetic driving member, 35 ... Armature as electromagnetic driving member, 60 ... Valve housing as housing member, 60a ... Valve body sliding hole, 60b ... As high pressure fluid passage High-pressure fuel passage, 60c ... High-pressure chamber as high-pressure fluid passage, 60d ... Low-pressure fuel passage as low-pressure fluid passage, 61
... Valve element, 63 ... Valve guide as a valve element guide member.

Claims (2)

[Claims] 1. A solenoid valve which is provided in the middle of a fluid passage that connects a high pressure fluid chamber and a low pressure fluid chamber and which opens or closes in accordance with energization of an electromagnetic drive member, and which has a valve body sliding hole. A housing member having a high-pressure fluid passage extending from the high-pressure fluid chamber and opening in a direction orthogonal to the valve body sliding hole, and a low-pressure fluid passage extending from the low-pressure fluid chamber and opening to the valve body sliding hole; A valve body having a sliding surface, the one sliding surface being in sliding contact with the valve body sliding hole of the housing member and being disposed in the housing member; and the other sliding surface of the valve body. A solenoid valve which is in contact with the valve body and is disposed so as to regulate a pressure receiving area of the valve body on the side of the low pressure fluid passage. 2. Use as an electromagnetic fuel spill valve provided in a fuel injection pump of a diesel engine.
Solenoid valve described in.