JPH11325297A - Plunger for solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase of sliding resistance, due to dirt in an electromagnetic valve, for a long time. SOLUTION: In a plunger 31 driven by the electromagnetic force of a solenoid 14, a first annular groove 35 and second annular grooves 36, 36 are provided in the periphery of a plunger mainbody 32 to form first-fourth large diameter portions 37, 38 put in slide contact a cylindrical sheet 5. A contact area between the plunger 31 and the cylindrical sheet 5 is smaller than that in a conventional structure where the plunger mainbody 32 has uniform diameter, so that sliding resistance is less increased even if dirt is deposited around the plunger 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plunger for a solenoid valve.

[0002]

2. Description of the Related Art Conventionally, for example, there is a solenoid valve shown in FIG. This solenoid valve 1 is provided in a bypass passage communicating between the upstream side and the downstream side of a throttle provided in the middle of the intake passage of the engine, and is used as an auxiliary flow control device for stabilizing the idling speed in the engine. And has the following configuration.

That is, the solenoid valve 1 has a block 4 in which an inflow passage 2 located on the upstream side of the bypass passage and an outflow passage 3 located on the downstream side thereof are formed. In the block 4, a tubular seat 5 having one end open to the outflow passage 3 and forming a valve chamber is provided on the inflow passage 2 side. The cylindrical sheet 5 is formed of a non-magnetic material and has flow control ports 6 and 6 at predetermined positions. Air flowing in from the inflow passage 2 is supplied from the flow control ports 6 and 6 to the inside of the cylindrical sheet 5. Through the outlet passage 3.

A plunger 7 is slidably fitted in the tubular sheet 5. Plunger 7 is plunger body 8
And a valve portion 9 formed at one end thereof and opening and closing the flow control ports 6 and 6 in accordance with the operation of the plunger 7. The valve section 9 is formed smaller in diameter than the plunger body 8. The plunger body 8 is provided at the base end of the valve portion 9.
While a stopper piece 10 having substantially the same diameter as that of the valve member 10 is externally inserted, a stepped portion is provided inside the tubular sheet 5 by making one end side on which the valve portion 9 is located to have a small diameter. The plunger 7 moves from the fully closed position (the position shown in FIG. 2) where the valve portion 9 closes the flow control ports 6 and 6 to one end side by the stopper piece 10 abutting on the step portion. Has been blocked.

On the other hand, the other end of the tubular sheet 5 is accommodated in a solenoid assembly 11 fixed to the block 4. The solenoid assembly 11 includes a bobbin 12 into which the other end of the tubular sheet 5 is fitted and a coil 13 wound around the bobbin 12.
, A core 15 housed in the bobbin 12, a core plate 16 connected to the core 15, and a metal cover 17 covering them.

The core 15 has a cylindrical shape, and the cylindrical sheet 5
The inside of one end side abutting on the other end is tapered so that the tapered end of the plunger body 8 can be accommodated. A stopper 18 that determines the limit of movement of the plunger 7 in the valve opening direction (upward in the figure) is screwed into the core 15, and a spring 19 that biases the plunger 7 in the valve closing direction is externally inserted into the stopper 18. ing.

A magnetic circuit is formed by the solenoid 14, the core 15, the core plate 16, the cover 17, and the plunger 7. When the solenoid 14 is excited, a suction force is generated in the plunger 7 in the valve opening direction. Further, the cover 17 is provided with a joint 17a which is fitted inside the block 4 and which is fitted outside the tubular sheet 5. When the solenoid 14 is excited, the cover 17 is connected via the joint 17a.
The magnetism is passed between and the plunger 7.

In the solenoid valve 1, a control current (duty control current) is supplied to the solenoid 14 from a controller (not shown) to move the plunger 7 in the axial direction. Is opened and closed to control the auxiliary air.

The plunger 7 has a communicating hole in the longitudinal direction penetrating through the shaft core and a peripheral surface of the valve portion 9 perpendicular to the communicating hole in order to balance the pressure at both ends of the plunger 7 during the operation described above. And a communication hole 20 in the transverse direction that is open to the outside. A plurality of large-diameter portions 21 having a larger diameter than other portions are provided on the peripheral surface of the valve portion 9 at regular intervals, and the large-diameter portions 21 pass through the flow rate control ports 6 and 6. Air, that is, dust in the mainstream, is prevented from entering between the tubular sheet 5 and the valve portion 9.

[0010]

However, in such a conventional solenoid valve 1, there is a clearance between the tubular sheet 5 and the plunger 7, and the inside of the tubular sheet 5 communicates with the air passage. Has become. Moreover, the cylindrical sheet 5
Inside, blow-by gas and EGR gas generated by the engine also flow, and contaminants such as solidified oil contained in the blow-by gas and carbon contained in the EGR gas are contaminated by the peripheral surface of the plunger 7 and the inner surface of the cylindrical sheet 5. Adheres to

For this reason, when the use period elapses, the sliding resistance of the plunger 7 increases due to the dirt adhering to the periphery of the plunger main body 8, which is a factor of deteriorating the controllability of the auxiliary air in the solenoid valve 1. Was. FIG.
Is a diagram of a basic experiment showing the relationship between the clearance between the cylindrical sheet 5 and the plunger main body 8 and the sliding resistance of the plunger 7, with respect to the case where there is no contamination at all.
When dirt collected from a market process product is applied, the sliding resistance of the plunger 7 increases.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a plunger capable of preventing an increase in sliding resistance due to adhesion of dirt in a solenoid valve for a long period of time. I do.

[0013]

According to a first aspect of the present invention, there is provided an electromagnetic valve which is slidably held in an opening and closing direction of a solenoid valve and driven by an electromagnetic force of a solenoid. In the plunger, a large-diameter portion protruding from a peripheral surface of the plunger, which is in sliding contact with a holding member that covers the periphery provided in the solenoid valve, protrudes.

In this configuration, the plunger is slidably held in the solenoid valve in the opening and closing direction of the solenoid valve by the large diameter portion slidingly contacting the holding member. Therefore, the contact area between the plunger and the holding member is smaller than in a configuration in which the diameter of the plunger is uniform.

In the invention of claim 2, the edge of the large-diameter portion in the opening and closing direction is angled. In such a configuration, when dirt adheres to the holding member and accumulates to some extent with the elapse of the use period, the edge of the large diameter portion protruding from the peripheral surface of the plunger is scraped off.

In the invention according to claim 3, the large-diameter portions are formed at both ends in the opening and closing direction. In such a configuration, the plunger does not tilt significantly inside the holding member.

Further, in the invention according to claim 4, the large diameter portion is formed at a position where it can always function as a magnetic transfer portion in the magnetic circuit of the solenoid valve regardless of the sliding position of the plunger. did.

In this configuration, the large-diameter portion protruding from the peripheral surface of the plunger slides with the holding member.
Even when the sectional area other than the large-diameter portion is small, when the solenoid is excited, a sufficient suction force is generated in the plunger.

According to the fifth aspect of the present invention, the large diameter portion can always function as a magnetic transfer portion in the magnetic circuit of the solenoid valve regardless of both ends in the opening and closing direction and the sliding position of the plunger. It was formed at the position.

In such a configuration, as described above,
The plunger does not tilt greatly inside the holding member,
In addition, the large-diameter portion protruding from the peripheral surface of the plunger slides on the holding member, so that even if there is a portion where the cross-sectional area is reduced in the plunger, the suction force generated by the plunger when the solenoid is excited is slightly reduced. Becomes

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a plunger 31 according to the present invention and a relationship between the plunger 31 and other members when the plunger 31 is used in a solenoid valve shown in the related art. The components other than the plunger 31 are denoted by the same reference numerals as those shown in FIG.

That is, the plunger 31 is slidably fitted inside the tubular sheet 5 which is the holding member of the present invention. The plunger 31 has a plunger main body 32 and a valve portion 33 formed at one end thereof and opening and closing the flow control port 6 with the operation of the plunger 31. The valve section 33 is formed to have a smaller diameter than the plunger body 32. A stopper piece 10 having substantially the same diameter as the plunger body 32 is externally inserted into the base end portion of the valve portion 33. The plunger 31 is moved from the fully closed position (the position shown in FIG. 1) where the valve portion 33 closes the flow rate control port 6 by the stopper piece 10 abutting on the stepped portion in the tubular sheet 5. Movement to is blocked.

On the peripheral surface of the plunger body 32, a first annular groove 35 having a large width is provided at a middle portion in the axial direction thereof.
Further, second annular grooves 36, 36 having a width smaller than that of the first annular groove 35 are provided on both sides thereof at a distance from each other.
As a result, the plunger body 32 includes a first large-diameter portion 37 located at one end where the valve portion 33 extends, and a second large-diameter portion 38 located at the other end having a tapered shape. Between the third large diameter portion 39 adjacent to the first large diameter portion 37 and the fourth large diameter portion 4 adjacent to the second large diameter portion 38
0 is formed. In addition, the first to fourth large diameter portions 37 to
38 has a shape whose edge in the axial direction is square.

The third large diameter portion 39 is always located at a position surrounded by the joint 17a of the cover 17, regardless of the sliding position of the plunger 31, that is, the cover 17 on the plunger 31 side.
It is formed at a position where it can function as a magnetic transfer part. Further, the fourth large-diameter portion 40 is a joint portion 1 of the cover 17.
7a near the opening on the solenoid 14 side,
When the plunger 31 initially moves immediately after the solenoid 14 is mainly excited, the cover 17 on the plunger 31 side
It is formed at a position where it can function as a magnetic transfer part.

The plunger 31 has a longitudinal communication hole 41 penetrating the shaft core and a peripheral surface of the valve portion 33 which is perpendicular to the communication hole 41 in order to balance the pressure at both ends of the plunger 31 during operation. A transverse communication hole 42 that opens is provided. A plurality of large-diameter portions 43 having a larger diameter than other portions are provided on the peripheral surface of the valve portion 33 at regular intervals. That is, dust in the mainstream is prevented from entering between the tubular sheet 5 and the valve portion 33.

In the present embodiment having the above-described structure, the plunger 31 slides in the axial direction (the opening and closing direction of the valve) by the first to fourth large-diameter portions 37 to 38 slidingly contacting the cylindrical sheet 5. It is freely held. Therefore, the contact area between the plunger 31 and the cylindrical sheet 5 is smaller than the conventional configuration in which the diameter of the plunger body 32 is uniform.

Therefore, it is possible to prevent the sliding resistance of the plunger 31 from increasing due to the adhesion of dirt in the solenoid valve for a long time. That is, as shown in FIG. 3, when dirt is applied in the same manner, the degree of increase in the sliding resistance is small as compared with the conventional plunger 7 shown in FIG.
As a result, when employed in an electromagnetic valve used as an auxiliary flow control device as in the present embodiment, it is possible to maintain the controllability of the auxiliary air for a long time.

Moreover, in the first to fourth large-diameter portions 37 to 38, since the edges in the axial direction are square, dirt adheres to the tubular sheet 5 side with the elapse of the use period. When the piles accumulate to some extent, they are scraped off by the angular edges of the large-diameter portions 37 to 38 projecting from the peripheral surface of the plunger main body 32, so that the amount of clearance reduction around the large-diameter portions 37 to 38 due to dirt is large. Never be.
Therefore, it is possible to prevent the sliding resistance from increasing for a longer period of time and to maintain the controllability of the auxiliary air.

A first large diameter portion 37 is provided at one end of the plunger main body 32, and a second large diameter portion 38 is provided at the other end.
Is provided, so that the plunger 31 is not greatly inclined in the tubular sheet 5. Therefore, wear of the plunger 31 due to the inclination can be prevented, and rattling of the plunger 31 with the elapse of the use period can be prevented.

Further, since the third large diameter portion 39 is always provided at a position where it can function as a magnetic transfer portion with the cover 17 regardless of the sliding position of the plunger 31, each large diameter portion 37 is provided. Even when the cross-sectional area of the plunger main body 32 in a portion other than the portions 40 to 40 is small, when the solenoid 14 is excited, a sufficient suction force is generated in the plunger 31.

Therefore, it is not necessary to increase the power supplied to the solenoid 14 or to make the solenoid 14 too large. As a result, it is possible to prevent an increase in sliding resistance of the plunger 31 due to adhesion of dirt in the solenoid valve for a long time without increasing power consumption and increasing the size of the solenoid valve.

Further, in the present embodiment, the fourth large diameter portion 40 can function as a magnetic transfer portion between the plunger 31 and the cover 17 at the time of the initial movement of the plunger 31 immediately after the solenoid 14 is excited. Position. This also allows the plunger 31 to generate a sufficient suction force when the solenoid 14 is excited.

In this embodiment, the plunger 31 has been described as having the valve portion 33 integrally formed with the plunger main body 32. However, the present invention is not limited to this. Even when the invention is adopted, the above-described effects can be obtained. Also,
The present invention may be applied to a plunger used for another electromagnetic valve that is not used as an auxiliary flow control device.

[0034]

As described above, in the first aspect of the present invention, the contact area between the plunger and the holding member is made smaller as compared with a configuration in which the diameter of the plunger is uniform. Therefore, it is possible to prevent an increase in sliding resistance due to adhesion of dirt in the solenoid valve for a long time.

According to the second aspect of the present invention, when dirt adheres to the holding member and accumulates to some extent as the use period elapses, the dirt is scraped off by the edge of the large diameter portion protruding from the peripheral surface of the plunger. I did it. Therefore, it is possible to prevent the sliding resistance from increasing due to the adhesion of dirt in the solenoid valve for a longer period of time.

Further, in the invention of claim 3, the plunger is prevented from being greatly inclined inside the holding member. Accordingly, it is possible to prevent the plunger from being worn due to the inclination inside the holding member, and to prevent rattling of the plunger with the elapse of the use period.

According to the fourth aspect of the present invention, the large-diameter portion protruding from the peripheral surface of the plunger slides with the holding member. A sufficient attractive force was generated in the plunger when excited. Therefore, it is not necessary to increase the power supplied to the solenoid or to make the solenoid too large. As a result, it is possible to prevent an increase in sliding resistance due to adhesion of dirt in the solenoid valve for a long time without increasing power consumption and increasing the size of the solenoid valve.

According to the fifth aspect of the invention, the power consumption and the size of the solenoid valve are not increased and the solenoid valve is not enlarged.
It is possible to prevent an increase in sliding resistance due to the adhesion of dirt in the solenoid valve for a long time, and at the same time, it is possible to prevent rattling of the plunger with the elapse of the use period.

[0039]

[Brief description of the drawings]

FIG. 1 is an explanatory view of a main part of a plunger and a solenoid valve according to an embodiment of the present invention.

FIG. 2 is a sectional view of a solenoid valve showing a conventional technique.

FIG. 3 shows a conventional technology and an embodiment of the present invention.
It is a figure showing the relation between the clearance between a cylindrical sheet and a plunger main part, and the sliding resistance of a plunger.

[Explanation of symbols]

 5 Cylindrical sheet 14 Solenoid 15 Core 16 Core plate 17 Cover 17a Joining part 31 Plunger 32 Plunger main body 33 Valve part 37 First large diameter part 38 Second large diameter part 39 Third large diameter part 40 Fourth large Diameter

Claims (5)

[Claims] 1. A plunger which is slidably held in an opening and closing direction of a solenoid valve and is driven by an electromagnetic force of a solenoid. A plunger for an electromagnetic valve, wherein a large-diameter portion in sliding contact protrudes. 2. A plunger for an electromagnetic valve according to claim 1, wherein an edge of said large diameter portion in said opening and closing direction is angled. 3. The plunger according to claim 1, wherein the large-diameter portions are formed at both ends in the opening and closing direction. 4. The large-diameter portion according to claim 1, wherein the large-diameter portion is formed at a position that can always function as a magnetic transfer portion in a magnetic circuit of the solenoid valve regardless of a sliding position of the plunger. Plunger for solenoid valve. 5. The large-diameter portion has both ends in the opening and closing direction,
3. A plunger for an electromagnetic valve according to claim 1, wherein the plunger is formed at a position which can always function as a magnetic transfer portion in a magnetic circuit of the electromagnetic valve regardless of a sliding position of the plunger.