JPH0791558A - Solenoid valve - Google Patents

Abstract

PURPOSE:To hold generated abrasion powder in a recess so as to prevent a contact surface from becoming rough by forming the surface of a movable iron core to be in contact with a fixed iron core into a three-dimensional uneven surface having a specific maximum height roughness, and applying specific viscosity lubricant to a recess formed on the contact surface. CONSTITUTION:A contact surface 12a of a movable iron core 12 of a solenoid valve to be in contact with a fixed iron core 11 thereof is ground for securing flatness, followed by shot-peening where hard beads having high hardness are blasted against the contact surface 12a at a high jetting speed. By using a hard bead having a diameter of about 80-240 microns, a surface roughness of the contact surface 12a is set to a maximum hight roughness Rmax of 7-20mum and a center line average roughness Ra of 0.7-2.0mum. 0.03-0.04cm<3> of turbine oil having the ISO viscosity grade VG of 32 in the industrial lubricant viscosity classification K2001 is applied to a three-dimensional uneven portion formed on the contact surface 12a, thus holding the turbine oil in a recess formed on the contact surface 12a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve used in industrial machinery and, more particularly, to prolonging the life of a solenoid valve used with high repetition frequency.

[0002]

2. Description of the Related Art Conventionally, a large number of solenoid valves have been used in industrial machinery. The structure of the solenoid valve is shown in FIG. The solenoid valve is composed of an upper half solenoid portion 22 and a lower half valve body 21. At the center of the solenoid portion 22 is a coil 13 in which a copper wire is wound around the body of a hollow cylindrical coil bobbin 14 having flanges at both ends.
A magnetic frame 15 is fixedly provided so as to surround the outer circumference of the coil 13. The fixed iron core 11 is inserted and fixed in the upper hollow hole of the coil bobbin 14. The collar portion of the fixed iron core 11 contacts the magnetic frame 1 to form a magnetic path.

A movable iron core 12 is slidably fitted in a lower hollow hole of the coil bobbin 14. A valve body 17 made of an elastic material such as rubber is embedded and fixed below the movable iron core 12. The movable iron core 12 is biased downward by a return spring 16, and the valve body 17 is in contact with the valve seat 18. The valve body 21 has an input port 19 communicating with the central hole of the valve seat 18 and an output port 20 communicating with the valve chamber 23. FIG. 1 shows a state in which the coil 13 is not energized. That is, the movable iron core 1
2 is urged downward by a return spring 16, and a valve body 17 is in contact with a valve seat 18. In this state, the input port 19 is not in communication with the output port 20. When the coil 13 is energized, the movable iron core 12 is attracted to the fixed iron core 11, and the movable iron core 12 contacts the fixed iron core 11. As a result, the valve body 17 is separated from the valve seat 18, and the input port 19 and the output port 20 are communicated with each other.

Here, the collision noise generated when the movable iron core 12 is brought into contact with the fixed iron core 11 is reduced, and the responsiveness that the movable iron core 12 adsorbed to the fixed iron core 11 is separated from the fixed iron core 11 is provided. It is generally required to be high. In addition, in the AC coil, when the movable iron core 12 is attracted to the fixed iron core 11, the movable iron core 11 is generated because the attraction force of the fixed iron core 11 changes in accordance with the AC frequency of the current supplied to the coil 13. It is required to reduce 12 vibration noises. Conventionally, when the flatness of the surfaces 11a, 12a with which the movable iron core 12 and the fixed iron core 11 contact each other is poor or the surface roughness is large, the true contact area is reduced and the air gap is increased, so that vibration noise is generated. It was known to grow. When disassembling the solenoid valve that became unusable due to the high vibration noise and observing the contact surface 12a of the movable iron core 12, the surface roughness was the maximum height roughness Rmax.
This is because it exceeds 20 μm. Therefore, in the conventional solenoid valve, it is considered that the vibration noise can be reduced by increasing the flatness and reducing the surface roughness by grinding the contact surfaces 11a and 12a. Maximum roughness due to grinding Rmax =
2 to 6 μm, center line average roughness Ra = 0.2 to 0.6 μm
It was about degree.

FIG. 5 shows measurement data of the surface shape of the contact surface 12a of the conventional solenoid valve. FIG. 5A shows data when tracing in a direction perpendicular to the grinding direction, and FIG. 5B shows data when tracing in a direction parallel to the grinding direction. The unevenness when traced in the direction perpendicular to the grinding direction is considerably larger than the unevenness when traced in the direction parallel to the grinding direction. A surface in which the shape of the unevenness is significantly different in the orthogonal direction is called a two-dimensional unevenness. The contact surface 11a is similar to the contact surface 12a. Maximum height roughness Rm mentioned above
ax = 2 to 6 μm, center line average roughness Ra = 0.2 to 0.
The data of 6 μm is data of unevenness when traced in a direction orthogonal to the grinding direction.

Further, by applying a small amount of lubricating oil such as turbine oil to the contact surface 12a, it has been attempted to reduce collision noise and vibration noise due to the lubricating action and the damper action. Here, when the viscosity of the lubricating oil is high, the movable iron core 12 becomes the fixed iron core 11
When the movable core 12 separates from the fixed core 11 due to the close contact with the fixed core 11, a delay time occurs. In order to prevent the occurrence of the delay time, the lubricating oil applied to the contact surface is ISO viscosity grade VG = 5 in industrial lubricating oil viscosity classification K2001.
A free-flowing product having a low viscosity of about 10 was used.

[0007]

However, some conventional solenoid valves have a life of 2 to 5 million times when air of extremely high dryness is used and a small amount of lubricating oil is applied. When the lubricating oil was not applied, the life was only about 1/10 of that. Here, the life is
The magnitude of vibration noise when the movable iron core 12 and the fixed iron core 11 are in contact with each other is less than or equal to a predetermined value, and the time when the movable iron core 12 is separated from the fixed iron core 11 when the energization is cut off is a predetermined time. The condition is as follows.

Conventionally, in order to reduce the vibration noise, the contact surface 1
The surface roughness of 2a is the maximum height roughness Rm by grinding finish.
ax = 2 to 6 μm, center line average roughness Ra = 0.2 to 0.
The amount of lubricating oil applied was about 6 μm and a small amount of lubricating oil was applied to the abutment surface 12a, but the amount of applied lubricating oil decreased due to repeated contact and separation of the movable iron core 12 with the fixed iron core 11,
Along with this, the collision sound increased at an accelerating rate. Since the low-viscosity VG = 5 or so was used as the lubricating oil, the adhesion of the lubricating oil to the contact surface 12a was small, which caused the lubricating oil to disappear quickly. When the amount of lubricating oil decreases, the collision noise increases at an accelerated rate.When the amount of lubricating oil decreases, the lubrication effect disappears and the surfaces come into direct contact with each other. It is considered that this is because the surface roughness of the surface acts as a material and accelerates.

This has been a particular problem in recent years with the rapid increase in the speed of automatic manufacturing equipment and the like, the frequency of use of the solenoid valve has rapidly increased, and the life of the solenoid valve has been short. For example, if an automatic assembly machine with a 2-second tact is operated for 24 hours, the number of operations per day is about 40,000, and the life span is only about 1 to 3 months. Since many solenoid valves are used, replacement was complicated.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a solenoid valve having improved durability.

[0011]

To achieve this object, a solenoid valve according to the present invention comprises a coil having a wire wound around the outer circumference of a coil bobbin, a fixed iron core fitted to one end of a coil bobbin hole, In a solenoid valve having a movable iron core that is slidably fitted to the other end of the coil bobbin hole and is attracted to a fixed iron core when the coil is energized, and a valve seat that is opened and closed by driving the movable iron core to switch communication between ports (1) The surface of the surface of the movable iron core that comes into contact with the fixed iron core is a three-dimensional uneven surface having good flatness and a maximum surface roughness of 7 to 20 μm, and (2) three-dimensional. It is characterized in that the lubricating oil of ISO viscosity grade VG of 20 to 64 is adhered to the concave portion of the uneven surface in an amount sufficient for continuous lubrication.

[0012]

When excited, the coil of the solenoid valve of the present invention having the above-described structure is slidable to the other end of the coil bobbin hole through the guide sleeve together with the fixed iron core fitted to one end of the coil bobbin hole. Suction the movable iron core to be fitted.
The valve seat is opened and closed by driving the movable iron core to switch communication between the ports. This opening / closing operation is repeated in the solenoid valve. Since the movable iron core and the fixed iron core repeatedly collide with each other during this opening / closing operation, abrasion powder is generated. Then, since the abrasion powder acts as an abrasive, the contact surfaces of the movable core and the fixed core become rough. The surface roughness of the contact surface is the maximum height roughness Rmax = 20.
From around μm, the vibration noise during adsorption becomes loud and it cannot be used.

The contact surface of the movable iron core of the solenoid valve of this embodiment is
It is a three-dimensional unevenness, and the maximum height roughness Rmax = 7 to 2
Since it is 0 μm, (1) the lubricating oil with high viscosity continues to adhere to the abutting surface of the movable iron core and exerts a lubricating action for a long period of time. The area is very small, and since the irregularities do not have directionality, the lubricating oil can freely flow in the concave portions, and as a result,
The adhesion of the contact surface due to oil content is reduced, and (3) abrasion powder or the like that occurs at the time of hitting in during the initial stage of use is stored in the recess, and does not act as a foreign matter on the suction surface.
It works like that.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solenoid valve which is an embodiment of the present invention will be described below with reference to the drawings. The structure of the solenoid valve of the present embodiment is almost the same as the structure of the conventional solenoid valve, and the difference is the structure of the contact surface 12a with which the movable core 12 contacts the fixed core 11. The same parts as those of the conventional solenoid valve will be described with the same reference numerals. Figure 1
FIG. 3 is a sectional view of a solenoid valve which is an embodiment of the present invention. The solenoid valve consists of an upper half solenoid 22 and a lower half valve body 21.
It is composed of At the center of the solenoid part 22,
Hollow cylindrical coil bobbin 1 with flanges on both ends
There is a coil 13 in which a copper wire is wound around the body of No. 4. Coil 1
A magnetic frame 15 is fixedly provided so as to surround the outer circumference of 3. The fixed iron core 11 is inserted and fixed in the upper hollow hole of the coil bobbin 14. The collar portion of the fixed iron core 11 contacts the magnetic frame 1 to form a magnetic path.

The movable iron core 12 is slidably fitted in the lower hollow hole of the coil bobbin 14. A valve body 17 made of an elastic material such as rubber is embedded and fixed below the movable iron core 12. The movable iron core 12 is biased downward by a return spring 16, and the valve body 17 is in contact with the valve seat 18. The valve body 21 has an input port 19 communicating with the central hole of the valve seat 18 and an output port 20 communicating with the valve chamber 23. FIG. 1 shows a state in which the coil 13 is not energized. That is, the movable iron core 1
2 is urged downward by a return spring 16, and a valve body 17 is in contact with a valve seat 18. In this state, the input port 19 is not in communication with the output port 20. When the coil 13 is energized, the movable iron core 12 is attracted to the fixed iron core 11, and the movable iron core 12 contacts the fixed iron core 11. As a result, the valve body 17 is separated from the valve seat 18, and the input port 19 and the output port 20 are communicated with each other.

The contact surface 12a where the movable iron core 12 of the solenoid valve of this embodiment contacts the fixed iron core 11 is ground to secure flatness, and then hard beads having high hardness are applied at a high injection speed. Shot peening is performed to spray the contact surface 12a. Hard beads have a diameter of 80-240
Using a micron type, the surface roughness of the contact surface 12a is
The maximum height roughness Rmax = 7 to 20 μm and the center line average roughness Ra = 0.7 to 2.0 μm. The reason why the maximum height roughness is 20 μm or less will be described. FIG. 7 shows the relationship between the contact surface roughness and the vibration sound level. This data is
It shows the data of the experiment without applying the lubricating oil. This is because, as indicated by K in the figure, if the contact surface roughness is 20 microns or less, it is confirmed that the vibration noise is small even without lubrication.

FIG. 4 shows measurement data of the surface shape of the contact surface 12a. 4A and 4B show data when tracing is performed in the orthogonal direction. According to the shot peening process, the surface shape shows almost the same data in the orthogonal direction, and there is no significant difference in tracing at any angle. This is called a three-dimensional uneven surface. In this embodiment,
Rmax = 10 μm. Turbine oil of ISO viscosity grade VG = 32 in industrial lubricating oil viscosity classification K2001 is applied to the three-dimensional uneven portion formed on the contact surface 12a by 0.03 to 0.04 cm ³ . This allows
Turbine oil is retained in the recess formed in the contact surface 12a.

Next, the operation of the solenoid valve having the above construction will be described. FIG. 1 shows a state in which no current is applied to the coil 3. The movable iron core 12 is biased downward by the return spring 16, and the valve body 17 is in contact with the valve seat 18. As a result, the input port 19 and the output port 20 do not communicate with each other. On the other hand, when an electric current is applied to the coil 3, a magnetic field is generated in the vertical direction of the fixed iron core 11, and the fixed iron core 11 attracts the movable iron core 12. Since this suction force is stronger than the spring force of the return spring 16, the movable iron core 12 moves to the position where it abuts on the fixed iron core 11. As a result, the valve body 17 separates from the valve seat 18, and the input port 19 and the output port 20 communicate with each other. This operation is repeated in the solenoid valve attached to the production line or the like.

The results of experiments on the durability of the solenoid valve of this embodiment are shown in FIGS. 2 and 3. FIG. 2 shows the relationship between the number of times the solenoid valve operates and the vibration noise generated by the solenoid valve. FIG. 3 shows the relationship between the number of operations of the solenoid valve and the time during which the movable core 12 separates from the fixed core 11 when the coil 13 is de-energized. In FIG. 2, the vibration noise measurement is a measurement value at a distance of 5 cm from the solenoid valve with a background noise of 45 dB in the laboratory. H indicates a limit control noise value of 53 dB. The reason for setting this condition is that, in the electromagnetic valve, it has been confirmed by experiments that the noise level is 45 dB rapidly increases when the noise level exceeds 53 dB at a distance of 5 cm. .

B1 indicates the average value of the noise data by the conventional solenoid valve, and A1 indicates the average value of the noise data by the solenoid valve of this embodiment. With conventional solenoid valves, 2
After exceeding, 000,000 times, some exceeded the limit control noise value H. According to the solenoid valve of this embodiment, the limit control noise value H does not exceed 100 million times. Next, consider the reason. As shown in FIG. 6, the maximum height roughness Rma, which is the difference between the convex portion T and the concave portion V, on the contact surface 12a.
Since x is as large as 7 to 20 μm and the convex portions T are three-dimensionally present, the fixed iron core 11 is considered at the micro level.
It is considered that there is a large proportion of the concave portions V that do not actually contact.

That is, the contact surface 1 as in the conventional solenoid valve.
When 2a is formed by a ground surface, since the projections T are connected in a mountain range, the proportion of the projections T that come into contact with the fixed iron core 11 is large, and therefore the area of the recesses V that do not come into contact is small. Further, since the surface roughness was also controlled to about Rmax = 2 to 6 μm, the volume formed by the concave portion V was small when the movable iron core 12 was in contact with the fixed iron core 11. In comparison with this, in the solenoid valve of the present embodiment, when the movable core 12 is in contact with the fixed core 11, the volume formed by the recess V is considerably large. It is the contact surface 12
This is because a has three-dimensional unevenness formed by the shot peening process, and the surface roughness is controlled to a large value of Rmax = 7 to 20 μm. This has been confirmed by experiments. FIG. 8 shows the relationship between the contact surface roughness and the detachment time of the movable iron core. This is because, as indicated by I1 to I4 in the figure, it can be confirmed that when the contact surface roughness is 7 μm or less, the disengagement time of the movable core rapidly increases.

As a result, as compared with the conventional solenoid valve, the solenoid valve of this embodiment retains a large amount of lubricating oil in the volume portion formed by the recess V. Further, in the solenoid valve of the present embodiment, the viscosity ISO viscosity grade VG of the lubricating oil is 20 or more and 64 or less, so that the viscosity of the lubricating oil is higher than that of the conventional one, so that the lubricating oil sticks to the recess V, It is rarely scattered and is retained on the contact surface 12a even if the number of times of use increases.
On the other hand, in the conventional solenoid valve, when the viscosity of the lubricating oil is increased, the movable iron core 12 becomes the fixed iron core 1 when the energization is turned off.
Since the time for releasing from 1 becomes long and the responsiveness of the solenoid valve deteriorates, a free-flowing lubricating oil having a low viscosity of about VG = 5 was used. That is, as shown in FIG. 8, it can be confirmed that when VG = 100 or more, the disengagement time of the movable core becomes long. On the other hand, with the lubricating oil of VG = 5, as shown in FIG. 9, when heated at a constant temperature, there is a problem that it evaporates in a short time like J2 and loses the lubricating effect. It is necessary to use VG = 20 or more.

It is considered that in the conventional solenoid valve, the generated abrasion powder mixes with the lubricating oil to form a lump-shaped abrasive material, which roughens the surface of the contact surface 12a. On the other hand, in the solenoid valve according to the present embodiment, as shown in FIG. 6, the generated wear powder M is held in the recess V together with the lubricating oil, so that the generated wear powder M is generated.
Therefore, the contact surface 12a is less likely to be roughened. In the conventional solenoid valve, since the volume of the concave portion is small, abrasion powder adheres to the abutting portion of the convex portion and roughens the surfaces of the abutting portions of the fixed iron core 11 and the movable iron core 12. In the solenoid valve, since the volume of the recess is large, the abrasion powder M is less likely to be retained in the recess and roughen the surfaces of the abutting portions of the fixed iron core 11 and the movable iron core 12.

Next, when the energization is turned off, the movable iron core 12
The time taken for the core to separate from the fixed iron core 11 will be described with reference to FIG. The data of the conventional solenoid valve is shown in B2, and the data of the solenoid valve of this embodiment is shown in A2. The conventional solenoid valve uses a low-viscosity lubricating oil to shorten the disengagement time, but the disengagement time is as long as 0.2 to 0.3 seconds in a range where the number of uses is small. When viewed at a micro level, the area of the convex portion T where the movable iron core 12 is actually in contact with the fixed iron core 11 is large. Therefore, in the conventional solenoid valve, if a high viscosity lubricating oil is used, ,
Since the lubricating oil enters the abutting portion of the movable iron core 12 and the fixed iron core 11 to enhance the adhesiveness, the lubricating oil having a low viscosity is used.

In the conventional solenoid valve, the disengagement time becomes shorter as the number of times of use increases. The reason why the number of times of use increases is that abrasion powder is generated and the movable iron core 12 and the fixed iron core 11
The movable iron core 12 and the fixed iron core 1 enter between the abutting parts
It is considered that this is because the adsorptivity with 1 is deteriorated. In the solenoid valve of this embodiment, the disengagement time is extremely short from the time when the number of operations is small to 100 million times. this is,
Since the contact surface 12a is three-dimensionally uneven, the area of the contact portion between the movable iron core 12 and the fixed iron core 11 is small when viewed at a micro level, and the movable iron core 12 is attracted by the residual magnetism of the fixed iron core 11. It is thought that this is because it is not much affected by power.

As described in detail above, according to the solenoid valve of the present embodiment, the three-dimensional unevenness is formed as the surface of the contact surface 12a of the movable iron core 12 which comes into contact with the fixed iron core 11, and the maximum height is obtained. Roughness Rmax = 7 to 20 μm, and contact surface 1
Since the high-viscosity lubricating oil of VG = 20 to 64 is attached to the concave portion of 2a and the generated abrasion powder is stored in the concave portion having a large volume, it is possible to prevent the surface of the abutting surface from being roughened, which causes noise. The life of the solenoid valve can be reduced to 1
It is possible to extend it to 0 times or more, and the result has exceeded 100 million times. Further, it is possible to always shorten the time during which the movable iron core 12 is separated from the fixed iron core 11 when the power is turned off.

In this embodiment, Rm is used as an evaluation model.
The experimental data when ax = 10 μm and the viscosity of the lubricating oil VG = 32 are shown. The experimental results show that Rmax = 7-
When 20 μm and the viscosity of the lubricating oil VG = 20 to 64, the result of the noise data does not exceed the limit control noise H when tested with the number of solenoid valve operations of 100 million times. Therefore, the effect of the present invention can be exhibited within the range.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in this embodiment,
Shot peening is used to form the three-dimensional unevenness, but another processing method may be used as long as the surface unevenness can be formed three-dimensionally. Further, in this embodiment, although turbine oil is used as the lubricating oil, the ISO
Other lubricating oils may be used as long as the viscosity grade VG = 20-64.

[0029]

As is apparent from the above description, according to the solenoid valve of the present invention, the surface of the movable iron core that abuts the fixed iron core has a maximum height roughness Rmax = 7 to 20 μm. VG = 20-
Since the viscosity lubricating oil of 64 is attached, the generated abrasion powder is stored in the concave portion having a large volume, and the contact surface can be prevented from being roughened, so that the generation of noise can be suppressed and the electromagnetic valve The life can be extended to 10 times or more of the conventional one. Further, it is possible to always shorten the time during which the movable core separates from the fixed core when the power is turned off.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a solenoid valve that is an embodiment of the present invention.

FIG. 2 is a diagram showing noise data of a solenoid valve.

FIG. 3 is a data diagram showing a disengagement time of a movable iron core of a solenoid valve.

FIG. 4 is a data diagram showing the surface shape of the contact surface of the movable core of the solenoid valve according to the embodiment of the present invention.

FIG. 5 is a data diagram showing a surface shape of a contact surface of a conventional electromagnetic valve movable iron core.

FIG. 6 is a conceptual diagram showing a surface state of an abutting surface of a movable iron core of a solenoid valve which is an embodiment of the present invention.

FIG. 7 is a data diagram showing the relationship between contact surface roughness and vibration sound level.

FIG. 8 is a data diagram showing the relationship between the contact surface roughness and the detachment time of the movable core.

FIG. 9 is a data diagram showing the relationship between the heating time and the remaining amount of oil.

[Explanation of symbols]

 11 Fixed Iron Core 12 Movable Iron Core 12a Abutment Surface 13 Coil 17 Valve Body 18 Valve Seat T Convex Part V Concave M Wear Powder

Claims (1)

[Claims] 1. A coil having a wire wound around an outer circumference of a coil bobbin, a fixed iron core fitted to one end of a coil bobbin hole, and a fixed iron core slidably fitted to the other end of the coil bobbin hole when the coil is energized. In a solenoid valve having a movable core that is attracted to the movable core and a valve seat that is opened and closed by driving the movable core to switch communication between ports, a surface of a surface of the movable core that contacts the fixed core has a maximum surface roughness. Is 3 to 20 μm, and the ISO viscosity grade VG is provided in the concave portion of the three-dimensional uneven surface.
20 to 64 lubricating oil is attached to the solenoid valve.