JP2785984B2 - Solenoid valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to improvements in, for example, an electromagnetic unloader valve.

(Prior Art) As an unloader valve, there is an electromagnetic unloader valve that controls opening and closing of a valve by using a suction force of a solenoid.

The electromagnetic unloader valve has excellent remote controllability since the release of the load can be controlled by an electric signal through a solenoid, and its application range is expanding.

(Problems to be solved by the invention) By the way, such an electromagnetic unloader valve is
It is very important that the variation in the suction force of the solenoid when operating the valve is small in order to enhance the stability of performance.

Since the suction force of the solenoid is inversely proportional to the square of the distance,
If the initial distance between the solenoid core and the plunger sucked by the solenoid is not precisely adjusted, the solenoid excitation current when the plunger starts operating will fluctuate greatly, and the operating characteristics of the valve will change significantly.

Therefore, if it is attempted to avoid such a problem without improving the dimensional accuracy of the initial interval, the exciting current of the solenoid is set to a value larger in advance in consideration of the dimensional variation than the designed rated value. However, since the attraction force of the solenoid decreases with the square of the distance as described above, the surplus current actually becomes a considerably large value.

Therefore, an object of the present invention is to provide an electromagnetic valve capable of improving performance stability without requiring strict dimensional control.

(Means for Solving the Problems) According to the present invention, an inlet and an outlet for hydraulic oil are connected to a storage space inside a valve body, and a seat portion communicating with the outlet is directly or indirectly connected to the storage space. A plunger that opens and closes in a closed manner is arranged so that a solenoid core that is located at the base end of the plunger and sucks the plunger against the return spring is opposed, and engages with the core to close the storage space. A spacer that is screwed until it comes into contact with the step portion of the valve body is provided, and a center pin is pressed in from the axial direction with a part of the plunger protruding,
The center pin is configured to regulate the effective stroke amount of the plunger between the core end face and the seat portion in accordance with the press-fitting allowance.

(Operation) Therefore, the axial movement amount, that is, the stroke amount of the plunger arranged in the storage space of the valve body is regulated by the center pin which is press-fitted with a part protruding from the plunger. By adjusting the press-fit allowance through the outlet after the valve is assembled, the effective stroke amount can be arbitrarily set.

As a result, the suction force of the solenoid exerted on the plunger can be accurately adjusted to a constant value, and the variation in valve performance can be reliably prevented.

(Example) Hereinafter, it demonstrates according to drawing. As shown in a first embodiment of FIG. 1, a solenoid 3 is attached to a base end cylindrical portion 2 of a valve body 1.

The solenoid 3 has a core 5 penetrating through the inner periphery of the coil bobbin 4, and a disk-shaped spacer 6 is provided at the tip of the core 5. A thread portion 7 is formed on the outer periphery of the spacer 6, and is screwed to the inner periphery of the proximal end tube portion 2 of the valve body 1 until it comes into contact with the step portion 9. The end face of the core 5 is somewhat protruded from the end face of the spacer 6, and the spacer 6
Engage with each other via the step 8.

In addition, the base end cylindrical portion 2 is located outside the solenoid 3.
A cylindrical case 10 is fitted on the outer periphery of the case, and an end face of the case 10 is sealed with a cap 11. The other end of the core 5 is fitted into a center hole of the cap 11, and is fixed by bolts 12. You. The coil bobbin 4 is pressed against the inner end face of the spacer 6 via a spring 13.

A stepped cylindrical valve storage space 15 is formed inside the valve body 1, and a hydraulic oil inlet 16 communicates with the storage space 15 from the side and an outlet 17 communicates from the axial direction. I have.

A plunger 18 is provided at the center of the storage space 15, and a disk 19 crimped to the base end of the plunger 18 faces the core 5 of the solenoid 3 at a predetermined interval (plunger stroke).

A stepped through hole 20 is formed at the center of the plunger 18, and the center pin 22 is partially protruded from the distal end side.
Is press-fitted, and a return spring 23 is
Are provided to urge the plunger 18 in a direction away from the core 5.

A cylindrical spool 25 is disposed outside the plunger 18 so as to be relatively slidable, and the spool 25 opens and closes the seat 30 communicating with the outlet 17.

Cylindrical spacers 26 and 27 are fitted on the inner and outer circumferences of the spool 25.

A return spring 28 is in pressure contact with the proximal end of the spool 25, and the return spring 28 is supported by a retaining ring 29 that locks on the inner periphery of the storage space 15, whereby the spool 25
To the seat portion 30. The seat 30
A thin sheet plate 31 is interposed between the and the spool 25.

An orifice 32 is formed on the side surface of the spool 25, and a through hole 33 is formed on the axis thereof.

The seat plate 34 is arranged inside the opening 33.
A hole is formed in the center of each of the sheet plates 31 and 34, and these sheet plates 31 and 34 are held by springs 40 and 41.

The center pin is provided on the inner end face of the spool 25.
The tip of 22 is in contact with the
33 is closed.

An annular chamber communicating with the introduction port 16 is provided on the outer periphery of the spool 25.
An orifice is formed on the inner periphery of the spool 25.
An internal chamber 36 communicating with the annular chamber 35 is formed through the annular chamber 32.When the spool 25 retreats from the seat portion 30,
The inlet 16 and the outlet 17 communicate with each other.
The rear chamber 38 at the rear end of the spool 20 is always in communication with the internal chamber 36 via a vertical groove 39 formed on the outer periphery of the plunger 18.

The configuration is as described above, and the operation will be described next.

When the solenoid 3 is not excited, the plunger
18 is separated from the core 5 by a return spring 23, and the center pin 22 at the tip thereof closes the opening 33 of the spool 25. The spool 25 is also a return spring 28
Therefore, the inlet port 16 and the outlet port 17 are completely shut off, and there is no flow of hydraulic oil.

On the other hand, when the solenoid 3 is excited by energization, the core 5 is magnetized and an attractive force acts on the plunger 18.

Therefore, the plunger is opposed to the return spring 23.
18 is drawn and the center pin 22 is the opening of the spool 25
Open 33. As a result, since the internal chamber 36 communicates with the low-pressure outlet 17 through the communication port 33, high-pressure hydraulic oil from the introduction port 16 flows into the internal chamber 36 from the annular chamber 35 through the orifice 32, and further flows through the communication port. Attempts to flow from 33 to outlet 17.

Since the hydraulic oil is throttled when passing through the orifice 32, a large pressure difference occurs between the annular chamber 35 and the internal chamber 36. Since the internal chamber 36 is also in communication with the rear chamber 38, the spool 25 is connected to the high-pressure annular chamber 35 and the low-pressure internal chamber 36 and the rear chamber 38.
Due to the pressure difference between the seat portion 30 and the return portion 28, the seat portion 30 moves away from the seat portion 30.

As a result, the inlet 16 and the outlet 17 communicate with each other through the annular chamber 35 to release high-pressure hydraulic oil and release the load connected to the inlet 16 (unloader).

By the way, the stroke amount of the plunger 18 sucked by the solenoid 3 is an initial distance from the end face of the plunger 18 to the end face of the core 5.
Is greatly changed according to the square of this distance.

In particular, when the initial interval is larger than the preset distance, the suction force applied to the plunger 18 is greatly reduced, and the valve operating characteristics become extremely unstable.

For this reason, the initial distance from the plunger 18 to the core 5 needs to be adjusted accurately.

However, in the present invention, the plunger stroke amount (initial interval) can be set to a predetermined value with high accuracy as follows.

First, in assembling the valve, the center pin 22 is press-fitted from the tip of the plunger 18 in advance so as to be slightly longer than the regular position, and in this state, the spool 25 is
And the plunger 18 and the like are incorporated in the valve body 1.

Then, while leaving the case 10 and the coil bobbin 4, the spacer 6 into which the core 5 is inserted is screwed into the screw portion 7 of the base tube 2 of the valve body 1.

Plunger 18 with extended allowance on the inner end face of spool 25
Since the center pin 22 of the spacer 6 is in contact, the plunger is attached to the end face of the spacer 6 when the spacer 6 is screwed halfway.
The end face 18 (the end face of the disk 19) comes into contact, but the spacer 6 is tightened until it comes into contact with the step portion 9 as it is.

With the tightening of the spacer 6, the center pin 22 is further pressed into the plunger 18. Spacer 6
Is completely in contact with the step 9, the spool 25 is pressed against the seat 30, and the plunger 18 is pressed against the inside of the spool 25. At this stage, the plunger 18 cannot move at all, In other words, the plunger stroke is correctly held at the zero point.

Next, a jig (not shown) is inserted into the spool 25 through the outlet 17.
And press the center pin 22 to the plunger 18
And slowly push the spool 25 back.

When the center pin 22 is press-fitted by a predetermined amount via the spool 25 in this manner, a gap is formed between the spacer 6 and the seat portion 30 so that the plunger 18 can move relative to the spool 25. This press-fitting amount becomes the effective stroke amount of the plunger 18.

As a result, the plunger 18, the spool 25, and the core 5
The axial dimension of the plunger 18, the stroke amount of the plunger 18 with respect to the spool 25, and the mutual dimension of the storage space 15 for determining the stroke amount of the spool 25 with respect to the seat portion 30, etc. The plunger effective stroke amount (initial interval) can be easily and accurately set to an arbitrary value.

Next, the embodiment of FIG. 2 will be described.
The seat part 30 was opened and closed directly by 18.
Direct-acting spool that operates by differential pressure
Not equipped with 25.

Therefore, when the solenoid 3 is excited, the plunger
18 is sucked, the center pin 22 separates from the sheet plate 34, the communication between the inlet 16 and the outlet 17 communicates, and the hydraulic oil escapes.

Also, the setting of the effective stroke amount of the plunger 18 at the time of assembling is performed by setting the center pin 22 to be slightly longer and press-fitting the center pin 22 into the plunger 18 by tightening the spacer 6 in the same manner as described above. Adjust the zero point, and then move the center pin 22 from the outlet 17 side through a jig.
May be press-fitted by a predetermined amount.

(Effect of the Invention) As described above, according to the present invention, the effective stroke amount of the plunger can be set to an arbitrary value without strictly controlling the axial length of the plunger and the distance between the core and the seat. Therefore, the operating characteristics of the valve can be stabilized stably at a low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, and FIG. 2 is a sectional view of the second embodiment. 1 ... valve body, 2 ... base end cylinder, 3 ... solenoid, 5 ... core, 6 ... spacer, 9 ... step, 15 ...
Storage space, 16: Inlet, 17: Outlet, 18: Plunger, 22: Center pin, 23: Return spring, 30: Seat.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16K 31/06 305 F16K 31/06 385

Claims (1)

(57) [Claims] 1. A plunger for connecting an inlet and an outlet of hydraulic oil to a storage space inside a valve body and for directly or indirectly opening and closing a seat portion communicating with the outlet is disposed inside the storage space. A solenoid core, which is located at the base end of the plunger and sucks the plunger against the return spring, is opposed to the solenoid, and is engaged with the core and abuts the step of the valve body so as to close the storage space. A spacer that is screwed into the plunger is provided, and a center pin is pressed in from the axial direction with a part of the plunger protruding,
An electromagnetic valve, wherein the effective stroke amount of the plunger between the core end surface and the seat portion is regulated in accordance with the press-fit amount of the center pin.