JPH0217258Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field This invention relates to a wet-type direct-acting solenoid valve, and in particular to a direct-acting shock valve that controls the sliding speed of the spool when the valve opens to prevent shock from being applied to the load. Regarding solenoid valves.

Prior Art A wet-type direct-acting solenoid valve, which is the object of this invention, is generally constructed as shown in FIG.

That is, a pair of solenoids 2 and 2' are provided on both sides of the valve body 1, and when either one of the pair of solenoids is energized, the movable iron core (not shown) of the solenoid is applied to the valve body 1 via the push rod 4. Push the inner spool 3 from one end and slide it in the direction of the arrow to open the oil path (between ports P, T and ports A, B).
Performs opening/closing or switching operations.

The movable iron core of each electromagnetic valve 2, 2' operates within a pressure-resistant tube filled with oil.

In such wet-type direct-acting solenoid valves, if the spool slides at a high speed when the valve opens, the valve operating time will be shortened, but the oil passage will open suddenly, causing a shock to the load. Become.

Therefore, as a conventional direct-acting type shockless solenoid valve that eliminates such a shock, there is one shown in FIG. Note that this second
The figure is a cross-sectional view of the left half, and parts corresponding to those in FIG. 1 are given the same reference numerals, and the right half is also constructed symmetrically.

The solenoid 2 of this solenoid valve includes a coil 22 wound around a bobbin 21 and molded inside a housing 20, a fixed iron core 24 to which a cylindrical core tube 23 is fixed, and a movable core 24 that is slidably installed inside the core tube 23. It consists of an iron core (armature) 25, a manual push pin 26, etc., and the push rod 4 fixed to the movable iron core 25 is connected to the fixed iron core 24.
It is slidably penetrated.

A pair of solenoids 2 as described above are screwed and fixed to both ends of the valve body 1, and form a spool end chamber 5 between them and the fixed core 24. A main spring 7 is interposed between the two to maintain the spool 3 in a neutral closed position at all times.

Further, an annular oil passage 27 is formed between the fixed iron core 24 of the solenoid 2 and the push rod 4, and the core tube 23 is filled with oil from the spool end chamber 5 through this oil passage 27.

The movable core 25 is formed with an oil passage hole 28 that communicates the left and right oil chambers, and an orifice 29 is provided therein.

When the coil 22 of the left solenoid 2 is energized, the fixed iron core 24 and the movable iron core 25 are excited and attract each other, and the movable iron core 25 moves to the right accompanied by the push rod 4, thereby causing the spool 3 in the valve body 1 Push the left end of and slide it to the right to open the ports TA and PB (see Figure 1).

When the coil 22 of the right solenoid (not shown) is energized, the spool 3 is slid to the left to open the ports P-A and B-T.

In this way, when the solenoid 2 slides the spool 3 of the valve body 1 to open the valve, the movable iron core 2
5 slides within the core tube 23, but in order to do so, the oil within the core tube 23 must move through the orifice 29 of the movable iron core 25, which slows down the sliding speed. Therefore, the sliding speed of the spool 3 is also slowed down, and the valve is opened slowly, so that no shock occurs.

However, such conventional direct-acting shockless solenoid valves have an orifice installed in the armature of the solenoid, so the orifice cannot be replaced unless the solenoid is disassembled and the armature replaced. , it was practically impossible to change the shotcress effect.

Furthermore, since the spool always slides at a low speed during the opening/closing or switching operation of the valve, there is a drawback that the total operating time becomes longer.

Purpose This invention was made in view of the above points, and provides a direct-acting type shotless solenoid valve that can easily change the shotless effect and shorten the total operating time when the valve is actuated. The purpose is to

Structure Therefore, the direct-acting type shockless solenoid valve devised by this invention has a piston hole that is open on the spool end chamber side in the fixed iron core of each solenoid, and a piston with an orifice is installed in the hole so that it can slide through the push rod. , each piston is urged toward the spool end chamber and locked in a predetermined position, and the oil chamber in the piston hole of the fixed core is communicated with the spool end chamber through the orifice of the piston, and the fixed core and The movable iron core is also communicated with an oil chamber in which the movable iron core slides through an oil passage between the push rod and the push rod.

When the spool of the valve body is driven by one solenoid and slides, only the push rod on the other solenoid side is pushed and the spool slides at a relatively high speed while the spool slides by the amount of overlap with the sliding hole. Thereafter, the piston is also pushed and the oil in the piston hole flows out into the spool end chamber through the orifice of the piston while sliding at a reduced speed, thereby opening the valve without a shock.

Embodiment Hereinafter, an embodiment of this invention will be described with reference to FIG.

FIG. 3 is a sectional view of the left half of the solenoid valve according to this invention, and the right half is also constructed symmetrically. Note that parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and their description will be omitted.

Fixed iron core 2 of solenoid 2 in this embodiment
4 has a piston hole 24b opened on the spool end chamber 5 side, which is concentric with the push rod through hole 24a, in a portion screwed into the valve body 1.

A piston 10 with an orifice is slidably provided in the piston hole 24b by penetrating the push rod 4, and is attached toward the spool end chamber by a pilot spring 12 interposed between the piston hole 24b and the bottom surface of the piston hole 24b. force, piston hole 24
A main spring 7 is inserted into the large diameter portion of b and interposed between it and the centering washer 6, and is locked in a predetermined position by a ring-shaped holder 13 which also serves as a locking member.

In addition, a cylindrical ring 14 is attached to the push rod 4.
When the ring 14 is slidably and closely fitted between the piston 10 and the tip surface 3a of the spool 3, and the ring 14 is brought into close contact with the piston 10, the tip of the spool 3 is in the neutral valve closing position. Distance x from surface 3a
is approximately equal to the overlap distance between the spool 3 and its sliding hole 8. Note that this ring 14 may be provided integrally with the piston 10.

Further, the cylindrical push rod 4 is chamfered except for a part near the tip that contacts the spool 3 to form an oil passage 15 between it and the fixed iron core 24, and is fixed by the piston 10. The oil chamber 16 formed in the piston hole 24b of the iron core 24 is communicated with the spool end chamber 5 through the orifice 11 of the piston 10, and the oil chamber 17 in which the movable iron core 25 in the core tube 23 slides through the oil passage 15. It communicates with

The movable core 25 of this embodiment has only an oil passage hole 28 for allowing the oil in the oil chamber 17 to move without resistance from one side partitioned by the movable core 25 to the other side when the movable core 25 slides. is provided, but no orifice is provided.

Next, the operation of this embodiment will be explained.

Now, a case will be described in which the right solenoid (not shown) is energized from the neutral state shown, and the spool 3 of the valve body 1 is pushed from the right end and slides to the left.

While the spool 3 slides by a distance x corresponding to the overlap section with the sliding hole 8, the tip surface 3
Since a does not come into contact with the ring 14, it slides against the biasing force of the main spring 7 while pushing only the push rod 4.

At this time, the amount of oil protruding into the oil chamber 17 of the push rod 4 increases, so that amount of oil must flow out into the spool end chamber 5 through the oil passage 15, oil chamber 16, and orifice 11. Since the diameter of 4 is small, the cross-sectional area S ₁
Since the oil is small and the amount of oil to be spilled (maximum S ₁ × x) is small, it spills out with almost no resistance,
It does not interfere with the sliding movement. Therefore, the spool shifts at high speed in this section.

Beyond this section, the tip surface 3a of the spool 3
comes into contact with the ring 14, and during the valve opening stroke y,
The spool 3 slides while pushing against the push rod 4 and ring 14.

At this time, the amount of oil that should flow out from the oil chamber 17 due to the increase in the amount of protrusion of the push rod 4 (maximum S ₁ ×
y) is small as in the previous case, but in addition, by sliding the piston 10 to the left via the ring 14, if the cross-sectional area is S ₂ , the amount of maximum S ₂ × y increases. From oil chamber 16 to orifice 11
through the spool end chamber 5.

In this case, since S ₂ is considerably larger than S ₁ , the amount of oil that needs to flow out will also be large, and the oil cannot flow out quickly from the orifice 11 , and the sliding speed of the piston 10 will be slow, so the sliding movement of the spool 3 will be affected. It becomes a resistance force against the friction, and acts as a cushion to reduce the sliding speed.

Therefore, the valve opens smoothly and does not cause any shock to the load. Moreover, since the spool slides at high speed in the overlap section, the total time required for the valve opening operation is shortened.

Also, when the solenoid 2 on the left side of the drawing is energized and its movable iron core 25 moves to the right with the push rod 4 to push the spool 3 from the left end and slide it to the right, the solenoid on the right side (not shown) moves. A piston with an orifice provides a cushioning effect after the overlap section.

Then, from the open state where the movable core 25 of the left solenoid 2 is at the sliding end to the right, the coil 22
When the power is cut off and the spool 3 returns to the neutral position by the force of the main spring 7 on the opposite side and closes the valve, oil is pumped in an amount corresponding to the increased amount of the push rod 4 protruding into the oil chamber 17. The oil must flow out from the oil chamber 17, but since the amount is small, it flows out through the orifice 11 with almost no resistance, so it returns at a relatively high speed.

In this embodiment, the push rod 4 is chamfered from the right end of the ring 14 to a point z, which is about x/3 smaller than the total stroke x+y of the push rod 4 pushing the spool 3 in the neutral state.

Therefore, in the valve open state in which the push rod 4 moves the full stroke to the right, its chamfered portion is exposed to the spool end chamber 5 from the right end of the ring 14. Therefore, at the initial stage of return, oil flows from the oil chamber 17 to the spool end chamber 5 even through the oil passage 15 formed by the chamfered portion, so that the return speed in the saturated state can be increased. In addition, the air inside the core tube is no longer limited to the orifice 11 of the piston, making it easier.

Effects As explained in the embodiments above, the direct-acting shockless solenoid valve of this invention is able to operate without applying shock to the load due to the cushioning effect of the orifice-equipped piston in the solenoid on the inactive side when the valve is opened. The valve can be opened smoothly, and the overlapping section between the spool and its sliding hole can increase the sliding speed of the spool, thereby shortening the total time required for the valve opening operation.

In addition, by removing the solenoid from the valve body, you can easily replace only the piston with orifice, so you can change the shotless effect by replacing the piston with a different orifice diameter depending on the purpose and application. can.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an example of a wet type direct acting solenoid valve, which is the subject of this invention, with only the valve body section taken in section, and Fig. 2 shows the left half of a conventional direct acting shockless solenoid valve. The vertical cross-sectional view, Figure 3, shows
FIG. 2 is a longitudinal sectional view similar to FIG. 2 showing an embodiment of the invention. 1... Valve body, 2... Solenoid, 3... Spool, 4... Push rod, 5... Spool end chamber, 7... Main spring, 8... Sliding hole, 10... Piston with orifice, 11... ...Orifice, 12...Pilot spring, 13
...Holder, 14...Ring, 15...Oil passage, 1
6, 17...Oil chamber, 20...Housing, 22...
... Coil, 23 ... Core tube, 24 ... Fixed iron core, 25 ... Movable iron core, 28 ... Oil passage hole.

Claims (1)

[Claims for Utility Model Registration] A pair of solenoids are provided on both sides of the valve body,
When either of the paired solenoids is energized,
A wet type direct acting solenoid valve in which a movable iron core of the solenoid pushes and slides a spool in the valve body from one end via a push rod to open/close or switch an oil passage, and the push rod of the solenoid is penetrated. A piston hole with an open spool end chamber side formed between the fixed iron core and the valve body is formed concentrically with a push rod through hole, and a piston with an orifice is inserted into each piston hole and slides through the push rod. each piston is biased toward the spool end chamber by a spring and locked in a predetermined position by a locking member, when the spool is in a neutral closed position; A distance corresponding to the overlap between the spool and its sliding hole is provided between each piston and each tip of the spool or a sliding member interposed between the two, and each of the fixing holes is provided by each piston. An oil chamber formed in the piston hole of the iron core is communicated with the spool end chamber through an orifice of each piston, and an oil passage is formed between each of the fixed iron cores and the push rod, so that each of the movable iron cores slides. A direct-acting shockless solenoid valve characterized in that an oil chamber and an oil chamber formed in a piston hole of each of the fixed iron cores are communicated with each other.