JPH0245567Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to a poppet type two-port valve, and in particular, aims to simultaneously achieve high-speed response and shocklessness as a valve element for a gasket type lock valve for direction and flow rate control. This invention relates to a poppet-type two-port valve.

[Prior art and problems to be solved]

A plurality of gasket-type poppet valves, each of which independently cuts off communication between a plurality of ports, are selectively operated by pilot pressure generated by selective excitation of a pilot solenoid valve, and the combination of these operations is changed. Logic valves for directional and flow rate control are known in which the switching functions of a plurality of poppet valves can be selected differently. This logic-type hydraulic switching valve has been used more and more recently because it has features such as low leakage, the ability to reduce hydraulic shock during switching, and the ability to reduce installation space. There is.

A conventional poppet type two-port valve used as a valve element of such a logic valve has a configuration as illustrated in FIG. That is, in FIG. 4, inside the valve body 1, there is a valve seat 1 at the lower part of the inner surface.
2 is fitted, and the lower end of the sleeve communicates with one main port 3, while the upper cylindrical part of the valve seat 12 has a hole 13 at an appropriate position and communicates with the other main port 4. A poppet valve 5 is slidably inserted into the sleeve, and a valve cover 6 is attached to the upper part of the valve body 1 so as to come into contact with the upper end of the sleeve 2.
A spring chamber 7 surrounded by the poppet valve 5 and the valve cover 6 is formed at the back of the poppet valve 5, and a spring 8 in the spring chamber 7 seats the poppet valve 5 on the valve seat 12. A stopper 9 having an adjustment screw 10 at the tail end for adjusting the retraction limit position of the poppet valve 5, in other words, the valve opening degree, is screwed into the stopper 9, and this stopper 9 is arranged so as to be able to come into contact with the back of the poppet valve 5. The valve cover 6 has a pilot passage 12 that communicates the spring chamber 7 and the pilot port 11.

Therefore, when the pilot signal pressure is introduced into the spring chamber 7 from the pilot port 11 through the pilot passage 12, the poppet valve 5 is seated on the valve seat 12, and the valve is connected from one main port 3 to the other main port. Although the pressure oil flowing to 4 is cut off,
Conversely, when the pilot signal pressure is not introduced into the spring chamber 7, the pressure oil from one main port 3 pushes up the poppet valve 5 and flows to the other main port 4.

However, at this time, the opening degree of the poppet valve 5 is limited to a predetermined value by the poppet valve 5 coming into contact with the stopper 9.

In this way, poppet type 2 for conventional logic valves
The port valve has a structure that controls the flow rate of pressure oil by opening and closing the poppet valve by controlling the pilot signal pressure to the back of the poppet valve.If the opening and closing speed of the poppet valve is too fast, a hydraulic shock may occur. Since this is undesirable, it is generally
A fixed orifice is placed in series with spring chamber 7.
The moving speed of the poppet valve 5 is suppressed by controlling the flow rate of the pilot pressure oil into or out of the valve.

However, if we try to increase the effect of preventing hydraulic shock, the movement of the poppet valve 5 becomes too slow and the responsiveness of the valve decreases. In order to find a compromise between the two and the switching response, the design and processing of the poppet tip shape as well as the adjustment of the opening of the fixed orifice become complicated, resulting in a significant increase in the number of man-hours required for adjustment in the actual machine. points are inevitable. In addition, in this case, the poppet shape becomes uniform for each product, which not only increases design man-hours and various management man-hours, but also requires a high degree of processing accuracy because the shape of each poppet is complex, making it difficult to standardize the product. It's causing trouble.

[Problem solving means and effects]

In order to solve the above-mentioned problems, the poppet type 2-port valve of the present invention has the tip of the poppet shaped as a shortless type that has a small gain in flow rate control area with respect to its movement stroke, and the movement speed of the poppet is By performing slow speed control only during a certain stroke section at the beginning and end of opening and closing, and performing high speed control for the remaining stroke, it is possible to suppress the occurrence of hydraulic shock and obtain high switching response. In this case, the two-step switching control of the poppet movement speed is performed using the movement of the poppet itself, so that the poppet can also be used as a spool for this switching. In addition, slow speed control and high speed control are performed using separate orifices.
Since variable types can be used for these, even if the product is standardized, individual optimum adjustments can be made relatively easily in the actual machine.

Specifically, the present invention provides a valve seat in the middle of a main oil passage communicating between the main ports of a valve body having a pilot port and a pair of main ports, and a spring is attached to this valve seat from the tail end side. The spring chamber on the tail end side of the poppet is connected to the pilot port via the pilot oil passage, and when the poppet is unseated against the spring. In a poppet-type two-port valve in which the retraction limit position of the poppet can be adjusted by the tip of the stroke adjustment screw in the spring chamber, a gradual change in the flow rate control area between the valve seat and the valve seat is provided with respect to the moving stroke. A poppet with a tip shape, a first orifice selectively connected in series in the pilot oil passage and a second orifice with a larger opening degree, and a position between the seating position and the fully open position of the poppet's movement stroke. The first orifice is connected in series in the pilot oil passage between the seating position and the halfway position, and from the halfway position to the fully open position, an oil passage that operates integrally with the poppet to connect and switch communication between the second and second orifices and the spring chamber so that only the second orifice is substantially connected in series in the pilot oil passage; The invention is characterized by comprising an opening/closing mechanism.

In one embodiment of the present invention, the oil passage opening/closing mechanism is provided through a groove formed in the inner circumferential wall of the poppet sliding hole in the valve body and through the poppet body so that the poppet moves from the halfway position to the fully open position. The spring chamber is connected to the pilot port by a pilot oil passage through the first orifice and the second orifice in order, and The groove communicates with a pilot oil passage between the first orifice and the second orifice.

In another embodiment, the first orifice may be a variable orifice whose opening degree can be adjusted, and the second orifice may be a fixed orifice with a preset opening degree. good.

In yet another embodiment, the first orifice includes a first check valve in parallel with a first check valve.
A second check valve including a variable throttle valve with a check and a second check valve facing oppositely to the first check valve in parallel.
The present invention also includes a series connection with a variable throttle valve with a check.

The structure and effects of the present invention will be more clearly understood from the following description of embodiments with reference to the drawings.

〔Example〕

FIG. 1 is a longitudinal sectional view showing the basic structure of the present invention, and FIG. 2 is an equivalent hydraulic circuit diagram thereof, and corresponding parts are given the same reference numerals in both figures. In the illustrated embodiment, the valve main body 20 includes a body portion 20a and a cover portion 2.
0b, a poppet sliding hole 22 is vertically penetrated through the body part 20a, and the lower end thereof is formed as one main port 24, and the passage 2 is formed from the middle.
6 is branched, and the end of this passage 26 is formed at the other main port 28, and the passage leading from one main port 24 to the other main port 28 via the passage 26 is a main oil passage.
A valve seat 32 is disposed at a position in the poppet sliding hole in the middle of this main oil passage by a cylindrical seat member 30 inserted from one main port 24 side. A poppet 34 is inserted into the valve seat 32 from the tail end side and is biased by a spring 36 so as to sit on the valve seat 32. The tip of the poppet 34 has a tapered shape with a small slope so as to provide a gradual change in the flow rate control area with respect to its movement stroke. The body portion 20a is also provided with a pilot port 38 and a pilot passage 40 communicating therewith, and the pilot passage 40 is a first port which will be described later.
It is connected to the spring chamber 42 on the tail end side of the poppet via an orifice, a second orifice, or an oil passage switching mechanism. A stroke adjusting screw 44 with a tip rod portion 44a protruding into the spring chamber 42 is disposed on the cover portion 20b.
By adjusting the protruding position of the tip rod portion 44a, it is possible to adjust the retracting limit position of the poppet 34 when the poppet 34 is released against the spring 36. This makes it possible to adjust the position of the main oil passage when the poppet is opened. The flow rate settings are now being fulfilled.

Now, the cover part 20b has a pair of variable throttle valves 46 and 48 with checks as a first orifice, and a second orifice.
A fixed orifice 50 as an orifice is provided. The variable throttle valves 46 and 48 with checks are preferably equipped with a viscosity-compensated orifice as shown in the example shown in the figure, in order to stabilize the throttle control (fine speed control) against changes in oil temperature. In the illustrated example, these orifices are connected to the spring chamber 42.
From the passage 52, through the second variable throttle valve 48 with a check and the first variable throttle valve 46 with a check, the passage 54 reaches the passage 56 via the fixed orifice 50, and the passage 56 is connected to the body. It is connected to the pilot passage 40 of the section 20a. In this case, two variable throttle valves with checks 4
6 and 48 are connected in series with the check directions facing each other, that is, in opposite directions, and a second The variable throttle valve 48 with a check opens its check so that the first variable throttle valve 46 with a check functions as a first orifice,
For oil flow in the opposite direction, the first variable throttle valve 46 with a check opens the check, and the second variable throttle valve 48 with a check functions as a first orifice. As mentioned above, the throttle opening of the fixed orifice 50 is wider than the throttle openings of these two variable throttle valves 46 and 48 with checks. That is, the throttle opening degrees of the two variable throttle valves 46 and 48 with checks can be set and adjusted as desired within a range that is equal to or less than the throttle opening degree of the fixed orifice 50, respectively, using the respective adjustment knobs 46a and 48a. Now, at a position near the tail end of the body of the poppet 34, an opening 60 having an opening width larger than a predetermined value in the axial direction of the poppet is opened in the outer circumferential surface of the poppet, and this hole 60 penetrates through the poppet body to prevent the spring from forming. It communicates with the inside of the chamber 42. Further, a groove 62 having a groove width of a predetermined value or more is provided on the inner circumferential wall of the poppet sliding hole 22 in correspondence with this opening 60, and this groove 62 is connected to a passage 58 in the cover part through a passage 64 in the body. The passage 58 is connected to the passage 54 between the variable check throttle valve 46 and the fixed orifice 50. These openings 60
The groove 62 and the passages 64 and 58 constitute an oil passage opening/closing mechanism which is the main part of the present invention. That is, with a predetermined intermediate position between the seating (fully closed) position and the fully open position of the movement stroke of the poppet 34 as the border, the opening 60 is formed during the stroke St ₁ from the seating position to the aforementioned intermediate position. The spring chamber 42 and the pilot port 38 are isolated from each other.
A pair of variable throttle valves 46 and 48 with checks are inserted in series into the pilot oil passage between the two. In this case, in the illustrated example, the fixed orifice 50 is also inserted in series, but the throttle opening of the fixed orifice 50 is controlled by the variable throttle valve 46,
Since it is more open than that of 48, it can be virtually ignored in terms of orifice function. and stroke St ₁
The opening 60 and groove 6
2, a pair of variable throttle valves 46 with checks,
48 is bypassed through the passages 64 and 58 by the communicating opening 60 and the groove 62, and the orifice 50 which functions in the pilot oil passage is fixed to the orifice 50.
I'm starting to do it only. said stroke
St ₁ is approximately determined by the insertion position of the opening 60 near the tail end of the body of the poppet 34, but can be adjusted by adjusting the axial position of the cylindrical shear member 30.

The operation of the embodiment shown in FIGS. 1 and 2 having the above configuration will be described below. FIG. 3 is a diagram showing the relationship between the stroke (vertical axis) and the time required for movement (horizontal axis) of the poppet 34 from the seated (fully closed) position to the fully open position.
I will also refer to the figure.

First, when the poppet 34 opens from the seated state, the spring chamber 42 is blocked from the groove 62 while the poppet 34 seated at time T ₀ is unseated against the spring 36 and moves by a constant stroke St ₁ . and
Therefore, the discharged pressure oil from the spring chamber 42 is transferred from the passage 52 to the check 48 of the second variable throttle valve 48 with a check.
b is pushed open and flows out to the pilot port 38 through the passages 54, 56, 40 through the throttle control part 46c of the first variable throttle valve 46 with a check, and is set by the adjustment knob 46a of the first variable throttle valve 46 with a check. By controlling the flow rate at the throttle opening (smaller than the throttle opening of the fixed orifice 50), the poppet 3
4 is suppressed to a very small speed determined by the throttle opening setting of the first variable throttle valve 46 with a check until the stroke _St1 is reached at time _T1 as shown in the characteristic _A1 of FIG.

Next, when the poppet 34 exceeds the stroke St ₁ , the opening 60 and the groove 62 communicate with each other and the passages 64, 5
Since the side passages of the variable throttle valves 46 and 48 are formed by the valves 8, substantially only the fixed orifice 50 is present in the pilot oil passage, and the poppet 3
The moving speed of No. 4 is set at a high speed determined by the opening degree of the fixed orifice 50, as shown by characteristic A ₂ in FIG. 3, and reaches the fully open position at time T ₂ . In addition, if the opening degree of the fixed orifice 50 is made small, after the time T ₂ as shown in characteristic A ₃ .
It will reach full throttle at _T3 .

By the way, if a throttle is inserted into the pilot oil passage of the valve of the conventional example shown in FIG. 4 at the throttle opening of the fixed orifice 50 that gives characteristic A ₃ , the conventional example will have characteristic B from the moment of unseating, as shown in characteristic B. As a result, a hydraulic shock at the beginning or end of closing is unavoidable.To prevent this, if a throttle with a throttle opening that provides characteristic _A1 is inserted into the pilot oil passage, the conventional example would be able to reach the fully open position as in characteristic C. The engine is in a slow speed control state until reaching the point _T3, and does not reach the fully open state until the time _T4 , which is much later than the time T3. On the other hand, with the present invention, the slow speed control of characteristic _A1 is possible for the section of stroke St ₁ from the beginning of opening to the end of closing, and then the high-speed characteristic is maintained until the fully open position.
Since the control can be performed with _A2 , the response time ( _T0 to _T2 ) is generally the same as that of the conventional example with characteristic B, and fine speed control without hydraulic impact during the stroke _St1 can be achieved.

When the poppet 34 is closed, the operation is performed in the reverse order as described above, at first high-speed control is performed by the fixed orifice 50, and then, when entering the stroke St ₁ section, slow-speed control is performed by the variable throttle valve 48 with a second check. Needless to say.

In the illustrated embodiment, the fixed orifice 50 is provided in the passage 56, but it is also possible to provide the fixed orifice 50 in the passage 58 instead of the passage 56. Furthermore, the fixed orifice 50 may be replaced with a variable orifice. In addition to being externally adjustable, it is also possible for the first and second variable throttle valves to be a single variable or fixed throttle valve.

[Effect of idea]

As described above, according to the present invention, in a poppet-type two-port valve for logic valves, it is possible to simultaneously prevent the occurrence of hydraulic shock at the beginning of opening and the end of closing, and ensure high switching response. Even with standardization, it is relatively easy to make optimal adjustments on actual equipment.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing the basic configuration of an embodiment of the present invention, Fig. 2 is an equivalent hydraulic circuit diagram, Fig. 3 is a poppet opening/closing speed characteristic diagram, and Fig. 4 is a longitudinal sectional view showing a conventional example. It is a front view. 20...Valve body, 22...Poppet sliding hole, 2
4, 28... Main port, 30... Cylindrical seat member, 32... Valve seat, 34... Poppet, 3
6...Spring, 38...Pilot port, 40,
52, 54, 56... passage (pilot oil passage),
42...Spring chamber, 44...Stroke adjustment screw,
46, 48... Variable throttle valve with check (first orifice), 50... Fixed orifice (second orifice), 60... Hole, 62... Groove, 58, 64
……aisle.

Claims (1)

[Claims for Utility Model Registration] (1) A valve seat is provided in the middle of a main oil passage communicating between the main ports of a valve body having a pilot port and a pair of main ports, and a spring is applied to this valve seat from the tail end side. The energized poppet is seated so that the main oil passage can be shut off, the spring chamber on the tail end side of the poppet is connected to the pilot port via the pilot oil passage, and the poppet is unseated against the spring. In a poppet-type two-port valve in which the retraction limit position of the poppet can be adjusted by the tip of the stroke adjustment screw in the spring chamber, a gradual change in the flow rate control area between the valve seat and the valve seat is provided with respect to the moving stroke. A poppet with a tip shape, a first orifice selectively connected in series in the pilot oil passage and a second orifice with a larger opening degree, and a position between the seating position and the fully open position of the poppet's movement stroke. The first orifice is connected in series in the pilot oil passage between the seating position and the halfway position, and from the halfway position to the fully open position, an oil passage that operates integrally with the poppet to connect and switch communication between the first and second orifices and the spring chamber so that only the second orifice is substantially connected in series in the pilot oil passage; A poppet type 2-port valve characterized by being equipped with an opening/closing mechanism. (2) When the oil passage opening/closing mechanism is installed through a groove formed in the inner circumferential wall of the poppet sliding hole in the valve body and the poppet body, and the poppet is located between the halfway position and the fully open position. The spring chamber is connected to the pilot port by a pilot oil passage via the first orifice and the second orifice in order, and the spring chamber is connected to the pilot port by the pilot oil passage through the first orifice and the second orifice in order. The poppet type two-port valve according to claim 1, wherein the groove is in communication with a pilot oil passage between the two ports. (3) The poppet type two port according to claim 1, wherein the first orifice is a variable orifice whose opening degree can be adjusted, and the second orifice is a fixed orifice whose opening degree is set in advance. valve. (4) The first orifice is connected to a first variable throttle valve with a check, which is equipped with a first check valve in parallel;
Utility model registration claim 1 consisting of a series connection with a second variable throttle valve with check, which is provided with a second check valve in parallel in the opposite direction to that of the check valve.
The poppet type 2-port valve described in .