JPH0443602Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The invention consists of a switching valve that switches the direction of pressure oil supply and a pump passage of this switching valve that is interposed so as to take two positions: a small opening and a large opening. 2 consisting of a poppet valve
Regarding speed control valves.

<Prior art> Conventionally, as this type of two-speed control valve, for example, the fifth
The one shown in the figure is known (Japanese Unexamined Patent Publication No. 1983-
Publication No. 203202). This two-speed control valve has a spool valve body 43 fitted in a spool valve chamber 42 in a main body 41.
The secondary port A connects the primary port P and tank port T to the rod chamber of the cylinder 45 by sliding the
and a throttle switching valve 44 which is switchably connected to the secondary port B communicating with the piston chamber of the cylinder 45, and a bottomed cylindrical poppet valve body having an orifice 45a at the center of the bottom and a throttle passage 45b passing around the orifice to the side. 45, a poppet valve chamber 46 having a drain port D
A spring 47 compressed in the valve chamber 46 connects the bottom outer edge of the poppet valve body 45 to the inlet port Po.
and a poppet valve 49 biased toward a valve seat 48 provided between the primary port P of the throttle switching valve 44 and the primary port P of the throttle switching valve 44.

Then, for example, when the cylinder 45 is raised by sliding the spool valve body 43 in the direction of arrow X in the figure and communicating the primary port P with the secondary port B and the tank port T with the secondary port A, respectively. , a switching valve 50 connected to the drain port D of the poppet valve chamber 46
When closed (left symbol position in the figure), spring 4
The pressure oil that is throttled to a small flow rate in the throttle passage 45b of the poppet valve body 45 seated at 7 is connected to the inlet port.
It is supplied from Po to the piston chamber of the cylinder 45 via the primary port P and the secondary port B, and the cylinder 4
5 rises slowly. On the other hand, when the switching valve 44 is opened (right symbol position in the figure), the inlet port Po
The poppet valve body 45 is moved by the spring 47 due to the drain flow passing through the orifice 45a of the poppet valve body 45, the drain port D, and the switching valve 50 to the tank 51.
Lift from the valve seat 48 against the
and the primary port P are opened, and a large flow of pressure oil flows through the 2
It is supplied to the piston chamber of the cylinder 45 through the next port B, and the cylinder 45 moves up at high speed. That is, the poppet valve 49, which has two positions, a small opening and a large opening, switches the flow rate to the cylinder 45 in two stages.

<Problems to be Solved by the Invention> However, the conventional two-speed control valve described above has a structure in which only the orifice 45a of the poppet valve body 45 is interposed as a restricting element between the inlet port Po and the tank 51, so that the switching is difficult. When the valve 50 is opened, a large amount of drain flows through the orifice 45a and the drain port D into the tank 51 at all times. Therefore, in order to raise the cylinder 45 at a high speed by closing the switching valve 50 and raising the cylinder 45 at a low speed in the example described above, the switching valve 50
When 0 is opened, there is a control problem in that the back pressure of the cylinder 45 drops instantaneously due to the above-mentioned large amount of drain flow, and the piston suddenly descends temporarily. Furthermore, an increase in the drain flow results in a decrease in the amount of hydraulic oil that can be supplied to the cylinder 45. In order to reduce this drain flow, the hole diameter of the orifice 45a can be reduced to, for example, 0.3 mm or less, but this requires precision and labor-intensive machining.
The disadvantage is that the speed control valve is expensive. Also,
Even when such an orifice is machined, there is a drawback that the orifice quickly becomes clogged with dirt in the hydraulic oil, and the dirt cannot be easily removed.

Therefore, the purpose of the present invention is to control the poppet valve of the two-speed control valve, which is composed of a spool switching valve and a poppet valve installed in the pump passage and which takes two positions, small opening and large opening, when the poppet valve is lifted to a large opening. To provide an inexpensive two-speed control valve which does not cause problems caused by drop of dead weight load or dust by having a simple structure in which the drain flow passing through an orifice is reduced and is not clogged with dust.

<Means for Solving the Problems> In order to achieve the above object, the two-speed control valve of the present invention has a spool valve body 23 fitted in a spool valve chamber 22 in a main body 21, as illustrated in FIG. A switching valve 3 that slides to switch and connect the primary port P and tank port T to one secondary port A and the other secondary port B, and a bottomed cylindrical poppet with an orifice 34a at the center of the bottom. The valve body 34 is fitted into a poppet valve chamber 27 having a drain port D, and a spring 36 compressed in the poppet valve chamber 27 connects the outer edge of the bottom of the poppet valve body 34 to the inlet port Po and 1 of 23 of the switching valve. A throttle 34 with a small opening is provided on the outer edge of the bottom of the poppet valve body 34 in a seated state by biasing it toward the valve seat 37 provided between the poppet valve body 34 and the next port P.
b narrows the flow path from the inlet port Po to the primary port P, while the drain flow from the orifice 34a of the poppet valve body 34 through the drain port D lifts the flow path between the inlet port Po and the primary port P. In the poppet valve 12 to be opened, the poppet valve body 34 is fitted into the poppet valve chamber 27 so as to fit inside the poppet valve body 34, and the poppet valve body 34 is lifted.
The stopper 35 is provided with a drain groove 35b formed in the distal end surface that abuts the inner surface of the bottom portion thereof and that extends radially across the distal end surface and communicates with the orifice 34a.

<Function> First, when the drain port D of the poppet valve chamber 27 is closed, the poppet valve body 34 is biased by the spring 36 compressed in the valve chamber 27 and connects its bottom outer edge to the inlet port Po and the switching valve 3. and the primary port P of the valve seat 37. Pressure oil is supplied to the inlet port Po through a small opening throttle 34b provided at the outer edge of the bottom of the poppet valve body 34 in the seated state.
From the primary port P, secondary ports A, B of the switching valve 3
A small flow rate is supplied to the actuator etc. through the , and the actuator is driven at low speed. Next, when the drain port D of the poppet valve chamber 27 is opened to the tank 17, the poppet valve body 34 is lifted against the spring 36 by the drain flow flowing from the orifice 34a of the poppet valve body 34 to the tank 17. , opens between the inlet port Po and the primary port P. At this time, the bottom inner surface of the lifted poppet valve body 34 is
The orifice 3 of the poppet valve body 34 comes into contact with the end surface of the stopper 35 fitted in the poppet valve chamber 27.
4a communicates with the drain groove 35b formed on the tip surface, the drain flow from the inlet port Po is constricted at these parts and becomes a small flow rate. In this way, the pressure oil flows through the opened poppet valve 12.
From inlet port Po to primary port P of switching valve 3, 2
A large flow rate is supplied to the actuator etc. through the next ports A and B, and the actuator is driven at high speed.Moreover, due to the above-mentioned reduction in drain flow, the dropping phenomenon of the dead weight load as in the conventional case does not occur when switching the large opening degree. Further, since the drain flow can be sufficiently restricted by the drain groove 35b on the stopper end surface, the hole diameter of the orifice 34a can be made large, and the dirt clogged in the drain groove 35b can be removed by the separating operation when the poppet valve body 34 is seated.

<Example> Hereinafter, the present invention will be explained in detail with reference to the illustrated example.

FIG. 1 shows a hydraulic circuit including a two-speed control valve of the present invention, in which a discharge line 2 of a constant displacement hydraulic pump 1 is connected to a four-port throttle switching valve 3 having load pressure detection ports R ₁ and R ₂ . The ports A and B of the throttle switching valve 3 are connected to the rod chamber and piston chamber of the hydraulic cylinder 6 via lines 4 and 5, respectively, and the T port is connected to the tank 8 via the tank line 7. is connected to. Then, by operating a lever against a spring, the throttle switching valve 3 is switched to the right or left symbol position in the figure to lower or raise the piston rod 6a of the hydraulic cylinder 6.

A pressure control valve 10 is interposed in the relief line 9 connecting the discharge line 2 and the tank line 7 near the hydraulic pump 1, and the pilot line 11 is connected to the spring chamber 10b having the spring 10a of the pressure control valve 10. The load pressure detection port R ₁ is connected to the load pressure detection port R 1 of the four-port throttle switching valve 3 through the pilot line 12 , while the load pressure detection port R ₂ is connected to the middle of the tank line 7 via the pilot line 12 . In the pressure control valve 10, when the 4-port throttle switching valve 3 is in the neutral position, the spring chamber 10b is connected to the pilot line 11,
Load pressure detection port R ₁ , R ₂ , pilot line 1
2 and the tank line 7 to the tank 8, and the discharge oil pressure from the discharge line 2 is applied to the spring 1.
When the spring pressure of 0a is reached, it functions as an unload valve that relieves the discharged oil, while when the 4-port throttle switching valve 3 is at the left and right symbol positions in the figure,
The load pressure of the cylinder 6 is guided to the spring chamber 10b via the pilot line 11, and when the discharge oil pressure reaches the total pressure of the load pressure and the spring pressure of the spring 10a, the discharge oil is relieved, and the pressure is released before and after the control valve 12, which will be described later. functions as a pressure compensation valve that maintains the differential pressure constant.

The control valve 12, which forms the main part of the present invention, is a poppet valve installed in the discharge line 2 between the 4-port throttle switching valve 3 and the pressure control valve 10, and is seated in the figure with a small throttle opening. The symbol position 12a on the left and the symbol position 12b on the right in the figure with a large throttle opening lifted from the valve seat are taken, and the spring chamber 12d with the spring 12c is connected to the upstream side of the discharge line 2 through the throttle 13. The pressure on the upstream side of the discharge line 2 is directly applied to the pilot chamber 12e facing the spring chamber 12d. As will be described later in FIG. 2, the throttle 13 is specifically an orifice 34 provided at the center of the bottom of a bottomed cylindrical poppet valve body.
a, and the aperture 14 in the left symbol position 12a
is a notch 34b provided at the outer edge of the bottom of the poppet valve body, and the throttle 15 in the symbol position 12b on the right is provided at the tip surface of the stopper that comes into contact with the inner surface of the bottom of the lifted poppet valve body, This is a drain groove 35b communicating with the orifice.

Further, the spring chamber 12d of the control valve 12 is connected to a tank 17 via a pilot line 16, and a cutoff position 18a is connected to the pilot line 16.
A spring-offset electromagnetic switching valve 18 is provided which has two positions, ie, a communication position 18b, and a communication position 18b. Then, the electromagnetic switching valve 18 is positioned at the cutoff position 18a, and the tank 17 in the spring chamber 12d of the control valve 12 is
By cutting off the communication to and applying the pressure of the discharge line 2 to the spring chamber 12d and the pilot chamber 12e of the control valve 12, the control valve 12 is positioned at the small opening position 12a by the biasing force of the spring 12c. By positioning the electromagnetic switching valve 18 at the communication position 18b and releasing the pressure acting on the spring chamber 12d from the discharge line 2 through the throttle 13 to the tank 17,
The control valve 12 is switched to the large opening position 12b by the pressure of the discharge line 2 acting on the opposing pilot chamber 12e, and the throttle openings of these two opening positions are equal to the throttle opening of the throttle switching valve 3. is set smaller than .

The operation of the hydraulic circuit of the above embodiment is essentially no different from that of the conventional example (Japanese Unexamined Patent Publication No. 58-203202).
This is detailed in the above-mentioned publication, and since it is not closely related to the problem to be solved by the present invention, only the main points will be described.

First, when the throttle switching valve 3 is positioned at the neutral position, ports A, B, P, and T of the throttle switching valve 3 are cut off, the hydraulic cylinder 6 stops at that position, and the spring of the pressure control valve 10 The chamber 10b is opened to the tank 8, and the oil discharged from the hydraulic pump 1 is unloaded at low pressure through the pressure control valve 10.

Next, when the throttle switching valve 3 is switched to the symbol position on the left in the figure, discharge oil is supplied to the piston chamber of the hydraulic cylinder 6 through the P port and the B port, and the piston rod 6a rises, and the pressure control valve 10 The pressure at port A of the throttle switching valve 3 is guided to the spring chamber 10b of the control valve 12, and the differential pressure across the control valve 12 is kept constant, and the flow rate of the discharged oil is controlled by the pressure-compensated throttle opening of the control valve 12. accurately controlled according to the degree of That is, when the electromagnetic switching valve 18 is demagnetized and discharge pressure is applied to the spring chamber 12d of the control valve 12, a small flow rate is obtained by the control valve 12 positioned at the small opening position 12a, and the electromagnetic switching valve 18 is activated. When the spring chamber 12d is energized and opened to the tank 17, a large flow rate is obtained by the control valve 12 positioned at the large opening position 12b. Therefore, the piston rod 6a of the hydraulic cylinder 6 moves up at low or high speed. Conversely, when the throttle switching valve 3 is switched to the right symbol position in the figure, the piston rod 6a of the hydraulic cylinder 6 can be lowered accurately at low or high speed in the same way.

FIG. 2 is a sectional view showing an example of a two-speed control valve in which the four-port throttle switching valve 3 and the control valve 12 described in FIG. 1 are integrated. This two-speed control valve has a main body 21
There are three lands 23 in the spool valve chamber 22 formed in
A spool valve body 23 having a, 23b, and 23c is slidably fitted therein. The above spool valve chamber 22
are provided with annular grooves T, 24, P, Po, P, 25, T in order from the left in the figure at regular intervals, and the annular grooves 24, 25 are connected to the piston chamber of the hydraulic cylinder 6. The secondary port B is connected to the secondary port A connected to the rod chamber of the hydraulic cylinder 6, respectively,
Tank port with annular grooves T and Po not shown, respectively.
In addition to communicating with the inlet port, the annular groove P,
Po, P communicate with each other through a trifurcated passage 26, while a poppet valve chamber 2 facing the annular groove Po
7 and a plug 28 having a drain port D communicating therewith, the front end of the poppet valve chamber 27 is connected to the passage 2.
It is screwed onto the main body 21 in a liquid-tight manner so as to face the intersection of the parts 6 and 6.

An adjustment bolt 29 with a spring receiver 30 fitted onto the head thereof is screwed onto one end of the spool valve body 23 protruding from the main body 21 so as to be movable forward and backward in the axial direction. A spring 32 is installed between the spring receiver 31 and the spring receiver 30, which are fitted onto the outside so as to be locked at one end, and the spring 32 is covered with the spring receiver 30.
A spring case 33 is fixed to the side of the spring 32 to precompress the spring 32.

Therefore, the spool valve body 23 is moved from the neutral position shown in the figure in which the ports are shut off against the spring 32 to the left side in the figure by the operation lever (not shown) attached to the other end of the spool valve body 23. If you move it to , the annular groove P which is the primary port and the secondary port A will become
While the annular groove T serving as the tank port and the secondary port B communicate with each other, and the piston rod 6a of the cylinder 6 is lowered (see the right symbol position in Figure 1), if it is moved to the right in the figure, each port Communication is switched and the piston rod 6a is raised (see symbol position on the left in FIG. 1). Also,
Since the opening degree between each port changes continuously according to the amount of movement of the spool valve body 23, the flow rate of hydraulic oil to the cylinder 6 can be controlled arbitrarily. That is, main body 2
The spool valve body 23 fitted into the spool valve chamber 22 of 1 constitutes the 4-port throttle switching valve 3 shown in FIG.

On the other hand, a bottomed cylindrical poppet valve pair 34 is slidably fitted into the poppet valve chamber 27 facing the annular groove Po serving as an inlet port, and a pair of poppet valves 34 is fitted with a base so as to fit inside the poppet valve body 34. Cylindrical stopper 35
is fitted with its base part in contact with the rear end of the valve chamber, and the base part of the stopper 35 and the poppet valve body 3 are fitted.
A spring 36 is compressed between the bottom inner surface of the poppet valve 4 and the poppet valve body 34 to urge the poppet valve body 34 toward a valve seat 37 provided at the boundary between the annular groove Po and the poppet valve chamber 27 and seat it. . As shown in FIG. 3, the poppet valve body 34 has an orifice 34a forming the orifice 13 shown in FIG. It has four notches 34b. Further, the stopper 35 is
As shown in FIG. 4, the drain groove 35d forming the aperture 15 in FIG. 1 that crosses in the radial direction (see FIG. 4c)
It consists of a disc-shaped base part 35c having on the back surface, and a shaft part 35a protruding from the center of the surface of this base part 35c, and the tip surface of the shaft part 35a forms the aperture 15 shown in FIG. 1 that crosses in the radial direction. Drain groove 35b
(see Figure 4 a, b), and the valve seat 3
The orifice 34a of the poppet valve body 34 is brought into contact with the bottom inner surface of the poppet valve body 34 lifted from the poppet valve body 7.
The drain groove 35b communicates with the drain groove 35b. The poppet valve body 34 fitted into the poppet valve chamber 27 constitutes the control valve 12 shown in FIG.
Note that the opening degrees of the orifice 34a, notch 34b, and drain grooves 35b, 35d that form the throttle are set to be considerably smaller than the throttle opening between the ports by the spool valve body 23, but this may cause problems in machining. For example, the diameter of the orifice 34a is about 1 mm. Further, the drain port D connected to the poppet valve chamber 27 is connected to the above-mentioned electromagnetic switching valve 18.
It is connected to tank 17 via.

The operation of the two-speed control valve having the above configuration is as follows.

Assume that the spool valve body 23 is now switched to the right in FIG. First, electromagnetic switching valve 1
8 is demagnetized to cut off communication between the drain port D of the poppet valve chamber 27 and the tank 17, the poppet valve body 34 is compressed between the stopper 35 and the valve 3.
6 to seat its bottom outer edge in a valve seat 37 provided between the inlet port Po and the primary port P of the spool valve. The pressure oil in the inlet port Po is throttled by the small opening notch 34b of the seated poppet valve body 34, passes through the passage 26, the primary port P, and the secondary port B, and enters the piston chamber of the cylinder 6 at a small flow rate. The piston rod 6a is raised at a low speed. Next, when the electromagnetic switching valve 18 is energized and the drain port D of the poppet valve chamber 27 is opened to the tank 17, the drain port D of the poppet valve chamber 27 is opened to the tank 17 from the orifice 34a of the poppet valve body 34 through the drain groove 35d.
7, the poppet valve body 34
is lifted against the spring 36, and the space between the inlet port Po and the primary port P is opened. At this time, the bottom inner surface of the lifted poppet valve body 34 touches the shaft portion 35 of the stopper 35 fitted in the poppet valve chamber 27.
a, and the orifice 34a of the poppet valve body 34 is formed in the drain groove 3.
5b, the drain flow from the inlet port Po is throttled to a small flow rate by this drain groove and the drain groove 35d on the back surface of the stopper base. Therefore, since a large amount of drain flow does not constantly flow to the tank 17 as in the conventional example shown in Fig. 5, the back pressure in the cylinder 6 does not drop instantaneously, and the piston rod 6a, which had been rising at a low speed, suddenly falls due to its own weight. There's nothing to do.
Thus, the pressure oil at the inlet port Po is supplied at a large flow rate to the piston chamber of the cylinder 6 through the opened poppet valve and through the same route as described above.
a is made to rise at high speed. Similarly, when the spool valve body 23 is switched to the left in FIG. 2, the piston rod 6a of the cylinder 6 can be lowered at low or high speed.

As described above, according to the two-speed control valve, when the poppet valve 34 is switched from the small opening position to the large opening position as described above, the falling phenomenon of the dead weight load does not occur as in the conventional case, which causes a control problem. , poppet valve 34
The diameter of the orifice 34a was changed to 0.3mm as before.
Since there is no need to do the following, clogging of the orifice due to dust is eliminated, and machining of the valve becomes easier and costs can be reduced. In addition, the dirt clogged in the drain groove 35b at the tip of the stopper shaft portion is naturally removed by the seating and lifting operation of the poppet valve body 34, and the conventional troubles caused by clogging are eliminated at once.

It goes without saying that the present invention is not limited to the illustrated embodiment.

<Effects of the invention> As is clear from the above explanation, the two-speed control valve of the invention connects the primary port and tank port from one side to the other by sliding the spool valve body fitted into the valve chamber in the main body. A switching valve is connected to the secondary port, and a poppet valve body, which has a bottomed cylindrical shape and has an orifice for drain, is fitted into a valve chamber with a drain port inside the main body, and a spring compressed into the valve chamber connects the inlet port. and a poppet valve, which is seated on a valve seat provided between the valve and the primary port of the switching valve, and which takes a small opening position due to a throttle on the outer edge of the bottom when seated and a large opening position when opened when lifted. A stopper is fitted in the poppet valve chamber so as to fit inside the poppet valve body,
A drain groove is formed on the tip surface of the stopper that contacts the bottom inner surface of the lifted poppet valve body, and a drain groove is formed in the tip surface that traverses in the radial direction and communicates with the orifice, so even if the hole diameter of the orifice is large, the poppet valve can be When the valve body is lifted, the drain flow flowing out from the drain port via this orifice can be narrowed down to a sufficiently small flow rate by the drain groove, and by reducing the amount of drain, the falling phenomenon is used for the self-weight load when the poppet valve body is lifted. It is possible to suppress the pressure to a level that does not cause any problems and increase the amount of pressurized oil that can be used for the load.
Problems can be solved by eliminating clogging of orifices and drain grooves caused by debris, and manufacturing costs can be reduced by making orifice machining easier.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a hydraulic circuit including the two-speed control valve of the present invention, Fig. 2 is a sectional view showing a specific example of the above-mentioned two-speed control valve, and Figs. 3 and 4 are the above-mentioned two-speed control valve. FIG. 5 is a sectional view showing a conventional two-speed control valve. 3...4-port throttle switching valve, 6...cylinder,
12... Control valve, 18... Solenoid switching valve, 21...
Main body, 22... Spool valve chamber, 23... Spool valve body, 27... Poppet valve chamber, 34... Poppet valve body, 13, 34a... Orifice, 14, 34
b...Notch, 35...Stopper, 15,35
b, 35d...Drain groove, 36...Spring, 37...
...valve seat, Po...inlet port, P...primary port,
A, B...Secondary port, D...Drain port.

Claims (1)

[Claims for Utility Model Registration] The spool valve body 23 fitted in the spool valve chamber 22 in the main body 21 is slid to connect the primary port P and tank port T to one secondary port A and the other secondary port A. A poppet valve chamber 27 having a drain port D is connected to a switching valve 3 which is switch-connected to port B, and a poppet valve body 34 having a bottomed cylindrical shape with an orifice 34a at the center of the bottom.
The bottom outer edge of the poppet valve body 34 is directed toward the valve seat 37 provided between the inlet port Po and the primary port P of the switching valve by a spring 36 fitted into the poppet valve chamber 27. When the poppet valve body 34 is in the seated state, the throttle 34b provided at the bottom outer edge of the poppet valve body 34 is used to connect the inlet port Po to the primary port P.
In a two-speed control valve consisting of a poppet valve 12 which opens between the inlet port Po and the primary port P by lifting the drain flow from the orifice 34a of the poppet valve body 34 through the drain port D, , which is fitted into the poppet valve chamber 27 so as to fit inside the poppet valve body 34, radially crosses the tip face of the lifted poppet valve body 34, and communicates with the orifice 34a. A two-speed control valve comprising a stopper 35 having a drain groove 35b formed therein.