JPS6227681Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention includes a pilot valve driven by a solenoid, and can control the amount of oil flowing through the main valve in proportion to the input current of the solenoid. This invention relates to a pilot type proportional solenoid valve.

[Conventional technology]

In recent years, with the demand for energy saving of mechanical devices through hydraulic control, it has been desired to significantly reduce the power consumption of solenoid valves, which are most commonly used in hydraulic systems.

Fig. 1 shows an example of a conventionally used energy-saving type pilot type proportional solenoid valve, in which a pilot valve component 2 and a solenoid component 3 for driving it are arranged on both sides of a main valve part 1 (Fig. (only the left half is shown), the spool of the main valve part 1 is moved by the pilot pressure controlled by the pilot valve component part 2, thereby saving energy and reducing the size.

[Problem that the invention attempts to solve]

However, in such a pilot type proportional solenoid valve, the main valve section 1 and the solenoid component section 3
A space is required for the pilot valve component 2 between the valve and the valve, the structure is complex, production costs are high, and miniaturization is limited.Furthermore, since it is an open control with no food back, it is difficult to avoid the effects of fluid force, etc. There were problems in that highly accurate proportional control according to the input current or voltage could not be performed, and the allowable flow rate was small.

In order to solve the problem of miniaturization, it is possible to house the pilot valve component inside the solenoid component, for example, in a fixed core, and such a solenoid valve for pneumatic circuits is already available. have also been proposed (for example, Japanese Patent Laid-Open No. 54-36623).

However, in order to achieve this with a pilot type proportional solenoid valve that requires a high-pressure pilot hydraulic output, the fixed parts that form each port of the pilot valve component cannot be moved by the generated hydraulic pressure, vibration, or impact force from a solenoid. The pilot valve component of the solenoid component and the main valve component must be reliably sealed to prevent oil from leaking outside in a narrow space. This was not possible because it was difficult to connect them directly.

This invention solves these problems by housing the pilot valve component of a pilot type proportional solenoid valve for hydraulic circuits within the fixed core of the solenoid component and directly connecting it to the main valve. The valve as a whole has been significantly downsized and consumes less power, always operates stably and reliably, and even when used at high oil pressure, there is no leakage of oil to the outside. The purpose is to enable highly accurate proportional control with a large allowable flow rate using the yield back system.

[Means for solving problems]

Therefore, the pilot type proportional solenoid valve according to this invention is constructed as follows.

A fixed iron core is fixed in a core tube with a solenoid coil on the outside, and a movable piece of magnetic material is installed in each fixed iron core of a pair of solenoid components so that it can slightly slide. A pilot valve component comprising a pilot spool to be driven and a sleeve into which the pilot spool is slidably fitted and which forms three ports whose connection relationship can be switched by sliding is housed and provided, and the above-mentioned A fitting part with the main valve part is provided at the end of the fixed core of each solenoid core tube, and each of the fixed cores has a large-diameter hollow part on the fitting part side and a side facing the movable piece. A stepped hollow part with a small diameter is formed, and the sleeve of the pilot valve component is fitted into the large diameter hollow part, and the pilot spool is brought into contact with the movable piece through the small diameter part, and the end wall of the sleeve is fitted. The large-diameter hollow part of the fixed iron core is partitioned, and an oil chamber is formed on the open end side of the main valve part to receive the pilot hydraulic output from the pilot valve component on the opposite side, thereby obtaining the pilot hydraulic output formed in the sleeve. Connect the C port, the P port to be connected to the pump, and the T port to be connected to the tank to each oil passage formed in the fixed iron core, and attach an O-ring to the outer periphery of the fitting part of each solenoid's core tube. The pair of solenoid components are directly connected to both sides of the main valve by fitting into the recesses provided on both end faces of the main body of the main valve, and the oil at the P port and T port formed on each fixed core is inserted into the recesses provided on both end faces of the main body of the main valve. connecting the passages to the oil passages of the P port and the T port formed in the main body, respectively, and
The oil passages of the C ports formed in the fixed iron core of each solenoid component are connected to the oil chamber of the solenoid component on the opposite side with the main valve section in between, and the main spool of the main valve section is connected to the oil chamber. With both ends facing each other,
A main spring is interposed between the end wall of the sleeve of each pilot valve component and the main body and main spool, and both ends of the rod are inserted into the center hole of the main spool and move axially with the main spool. The rod passes through the end wall of the sleeve of each pilot valve component, and a feedback spring is interposed between both ends of the rod and each pilot spool.

[Effect]

This invention uses the above-mentioned means to improve the pilot valve component of a pilot proportional solenoid valve for a hydraulic circuit.
Everything is housed within the fixed core of the solenoid component and connected directly to the main valve, eliminating the need for a separate space for the pilot valve component, resulting in significant downsizing and power savings for the proportional solenoid valve as a whole. It was realized.

Furthermore, to explain the operation using FIGS. 2 and 3 corresponding to the embodiment, the fitting part of the core tube 33 in the solenoid component 3 is connected to the main valve part 1 by attaching an O-ring 40 to its outer periphery. The fixed iron core is fitted into a recess provided in the end face of the main body 11 of the main body 11, so that the O-ring 40 securely seals the core against the outside, eliminating the risk of oil leakage and forming an oil passage for each port. There is no need to increase the diameter as in the case of sealing at the end face of 34.

In addition, the sleeve 21 of the pilot valve component is
The spring force of the feedback spring 24 is f, and the spring force of the main spring 43 is
F ₁ , the spring force of the sealing spring 44 is
Assuming F ₂ , when the solenoid is OFF, it is pushed to the left in Fig. 3 by the spring force (F ₁ +F ₂ -f), and is pressed against the step in the hollow part of the fixed iron core 34 and held fixed. .

And when the solenoid on the opposite side is ON,
Since the pilot hydraulic pressure output from the pilot valve component on the opposite side is introduced into the oil chamber of the C ₂ port,
The sleeve 21 is strongly pressed and fixed by the hydraulic pressure.

When the solenoid is ON, the spool 22 moves to the right by the movable piece 35, compressing the feedback spring 24, and the force that moves the sleeve 21 to the right in FIG. 2 increases. , C ₁
The pilot oil pressure output of the port is applied to the oil chamber of the _C2 ' port on the opposite side, causing the main spool 12 and rod 13 to move to the left in Fig. 2, so the main spring 43 and sealing spring 44 are compressed, and their spring force is increased. Sleeve 21
is strongly pressed to the left in FIG. 3, and is firmly fixed and held within the fixed iron core 34 without moving even when subjected to vibrations or shocks.

Therefore, without causing chatter phenomenon etc.
Reliable control operations can be performed at all times.

Furthermore, since there is no need to fix the sleeve 21 to the fixed core 34 by welding, adhesive, etc., it is not necessary to disassemble or
Assembly and replacement of internal parts such as the pilot spool 22 are also easy.

In addition, since the rod 13 for performing force feedback is made separate from the main spool 12, by creating a slight play in the radial direction between the two, the center of the through hole between the main spool 12 and the sleeve 21 can be adjusted. Even if there is a slight deviation, it can be absorbed, so the tolerance for centering errors is increased and manufacturing is easy.

〔Example〕

An embodiment of this invention will be described below with reference to FIGS. 2 and 3.

Fig. 2 is a longitudinal sectional view showing the left half of a pilot type proportional solenoid valve as an embodiment of this invention.Actually, there is a right half on the right side that is symmetrical to this, so in the following explanation, If necessary, portions of the right half corresponding to portions of the left half will be explained by adding dashes to the reference numerals (not shown).

In the pilot type proportional solenoid valve according to this invention, the solenoid component 3 is directly connected to the main valve part 1, and the pilot valve component 2 is directly connected to the solenoid component 3.
Built-in.

The solenoid component 3 comprises a solenoid coil 32 wound around a bobbin 31, a fixed iron core 34 fixed within a cylindrical core tube 33, and a movable piece (movable iron core) 35 made of a magnetic material arranged inside so as to be able to slide slightly.

The right end of the core tube 33 fits into the main valve part 1, and the left end has a small diameter, into which a manual lever rod 36 is fitted via a zero adjustment screw 37, and a spring 38 is engaged between it and the movable piece 35. I'm wearing it.

The solenoid coil 32 wound around the bobbin 31 is molded into a coil housing 39 and fitted onto the outer periphery of the core tube 33.

A stepped hollow part consisting of a large-diameter hollow part 34a and a small-diameter hollow part 34b following it is provided in the fixed core 34. A sleeve 21 is fitted into the large-diameter hollow part 34a, and a pilot spool 2 is inserted into the sleeve 21.
2 is fitted so as to be able to slide slightly, forming a pilot valve component 2.

This pilot spool 22 has a sleeve 21
A feedback spring 24 is engaged between the spring 23 and the spring 23 which is slidably mounted on the iron core 34 to provide a leftward movement, and the left end passes through the small diameter hollow part 34b of the fixed iron core 34 and comes into contact with the movable piece 35. ing.

The spring receiver 23 has a rod 13 that is inserted into the center hole of the main spool 12 of the main valve section 1, which will be described later, and that moves together with the main spool 12 in the axial direction.
One end of the sleeve 21 passes through and abuts the end wall of the sleeve 21.

In addition, the pilot spool 22 has an oil passage 22a.
is formed through the movable piece 35, and a groove 35a is formed on the outer periphery of the movable piece 35.
is provided to allow the movement of oil in the left and right oil chambers to reduce resistance when the pilot spool 22 and movable piece 35 move.

Further, the sleeve 21 is provided with a P ₁ port to be connected to the pump, a T ₁ port to be connected to the tank, and C ₁ and C ₂ ports to transmit and receive pilot hydraulic output. Connect the P ₁ port, T ₁ port, and C ₁ port of this pilot valve component 2 to the P port (high pressure side), T port (low pressure side) of the main valve part 1, and the C ₂ ' port of the right half, respectively. Oil passages 34c, 34d, and 34e are formed for this purpose.

In this way, the solenoid component 3 in which the pilot valve component 2 is housed within the fixed core 34 is
In order to connect the main valve part 1 consisting of the main body 11 and the main spool 12, a centering washer 41 and a sealing washer 42 are interposed between the sleeve 21 and the main body 11 and the main spool 12. After the main spring 43 and the sealing spring 44 are engaged between the washer 41 and the sealing washer 42 and the sleeve 21, respectively, and the rod 13 is inserted into the center hole of the main spool 12, the main body of the main valve part 1 is inserted. An O-ring 40 is attached to the outer periphery of the fitting part of the core tube 33 and fitted into the recessed part 11, the flange plate 45 is fixed to the main body 11 with bolts 46, and the coil housing 39 in which the solenoid coil 32 is molded is attached. What is necessary is to fit it into the core tube 33.

Note that 47 and 48 are O-rings for sealing.

FIG. 3 shows this pilot type proportional solenoid valve as a hydraulic path diagram, and 2' and 3' are the pilot valve component and solenoid component on the right side, which are also omitted in FIG. 2.

Next, the operation of this embodiment will be explained.

When the solenoid coil 32 is not energized, the pilot spool 22 moves to the left by the force of the feedback spring 24 and is in the state shown in FIG. 2, and the C ₁ and C ₂ ports of the pilot valve component 2 are closed.
_T1 port, and no pilot oil pressure is applied to the main spool 12 of the main valve part 1, and it is pushed by the left and right main springs 43, 43' to a neutral position, and the main valve part 1 is in a neutral position as shown in FIG. Both A port and B port of No. 1 are closed.

Here, for example, when an input current is applied to the left solenoid coil 32, the fixed iron core 34 and the movable piece 35 attract each other, so the movable piece 35 resists the feedback spring 24 and inputs the input to the pilot spool 22. Move to the right in proportion to the current.

As a result, the communication between the T ₁ port and the C ₁ port is restricted, and the P ₁ port communicates with the C ₁ port, so high-pressure pilot oil pressure is applied from the C ₁ port to the right C ₂ ′ port, and the main Spring 43
The main spool 12, rod 13, and sealing washer 42 are pushed to the left against the force.

At this time, the feedback spring 24 is also pressed to the left via the spring receiver 23, so the pilot spool 22 is pushed back and stops at a balanced position, producing a force feedback effect.

Due to this action, the proportional solenoid valve has the characteristic that its main spool is less susceptible to disturbances such as fluid force. Therefore, it becomes possible to extremely increase the allowable flow rate of the main valve section.

Now, assuming that the amount of displacement of the main spool 12 is X, the amount of displacement of the pilot spool 22 is x, and the input current to the solenoid coil ₃₂ is _i , the following relationship is established:

In addition, K ₁ and K ₂ are feedback springs 2
This is a constant determined by the spring constant of 4.

In this manner, the displacement of the main spool 12 is proportional to the input current to the solenoid coil 32, and the amount of oil flowing through the main valve portion 1 can be controlled proportionally with high accuracy based on the input current.

Since the resistance of the solenoid coil 32 is constant, the input current is proportional to the input voltage, making it possible to proportionally control the flow rate depending on the input voltage.

Furthermore, if the input current is made equal to the extent that the pilot spool 22 is sufficiently displaced, on/off control will be performed like a normal pilot type solenoid valve.

Furthermore, by rotating the zero adjustment screw 37, the manual push rod 36 can be moved and controlled manually.

By the way, according to this embodiment, the fitting portion of the core tube 33 in the solenoid component 3 is fitted into the recess provided in the end face of the main body 11 of the main valve portion 1 with the O-ring 40 attached to its outer periphery. Therefore, the O-ring 40 provides a reliable seal to the outside and there is no risk of oil leakage, and the diameter is increased as in the case of sealing at the end face of the fixed iron core 34 that forms the oil passage of each port. There's no need.

Furthermore, the sleeve 21 of the pilot valve component
, the spring force of the feedback spring 24 is f, and the spring force of the main spring 43 is
F ₁ , the spring force of the sealing spring 44 is
Assuming F ₂ , when the solenoid is OFF, it is pushed to the left in Fig. 3 by the spring force (F ₁ +F ₂ -f), and is pressed against the step in the hollow part of the fixed iron core 34 and held fixed. .

And when the solenoid on the opposite side is ON,
Since the pilot oil pressure output from the pilot valve component on the opposite side is introduced into the oil chamber of the _C2 port, the sleeve 21 is strongly pressed and fixed by the oil pressure.

When the solenoid is ON, the spool 22 moves to the right by the movable piece 35 and compresses the feedback spring 24, increasing the force that moves the sleeve 21 to the right in FIG. The pilot hydraulic output of the _C1 port is applied to the oil chamber of the _C2 ' port on the opposite side, causing the main spool 12 and rod 13 to move to the left in Fig. 2, so the main spring 43 and sealing spring 44 are compressed. Since the spring force is strengthened, the sleeve 21 is strongly pressed to the left in FIG. 3, and is held fixed within the fixed iron core 34 without moving even when vibrations or shocks are applied.

Therefore, without causing chatter phenomenon etc.
Reliable control operations can be performed at all times.

Furthermore, since there is no need to fix the sleeve 21 to the fixed core 34 by welding, adhesive, etc., it is not necessary to disassemble or
Assembly and replacement of internal parts such as the pilot spool 22 are also easy.

In addition, since the rod 13 for performing force feedback is made separate from the main spool 12, by creating a slight play in the radial direction between the two, the center of the through hole between the main spool 12 and the sleeve 21 can be adjusted. Even if there is a slight deviation, it can be absorbed, so the tolerance for centering errors is increased and manufacturing is easy.

In the above embodiment, a normal pilot spool 22 is used in the three-way function pilot valve component 2.
However, other than this spool, for example, a spool having a poppet-shaped portion may be used, and it goes without saying that the main spool 12 of the main valve portion 1 can be changed depending on the applied circuit.

In addition, the pilot type proportional solenoid valve of this invention can be widely applied to intrinsically safe solenoid control valves, power-saving solenoid valves, etc., and with some modifications, it can also be applied to solenoid pressure control valves. .

[Effect of idea]

As described above, according to this invention, all the pilot valve components are housed in the solenoid component, so there is no need for an independent spacer for the pilot valve component.

Moreover, the pilot valve component can be assembled by using the hollow part of the fixed core through which the push pin for pushing the pilot spool is inserted in conventional solenoids, and the push pin can be removed and the movable piece can be used to directly push the pilot spool. There is no need to increase the size of the solenoid component.

Furthermore, since the solenoid component can be made larger than the pilot valve component, the number of turns of the coil can be increased, which increases the excitation force and is extremely effective in reducing power consumption.

In addition, a force feedback system was adopted in which the left and right pilot pressures are guided to the other side to push the main valve in the opposite direction to the pilot valve, and the pilot valve is pushed back via the feedback spring, so the amount of displacement of the main valve is controlled by the solenoid. The input current of the solenoid is proportional to the input current or input voltage of the solenoid, and the fluid flow rate determined by the amount of displacement of the main valve can be controlled accurately proportionally by the input voltage, and the maximum permissible value is less susceptible to the influence of fluid force. A pilot type proportional solenoid valve with a large flow rate can be provided.

Furthermore, since sealing between the pilot valve component and the main valve can be reliably achieved in a small space, there is no risk of oil leakage even when used in a high pressure hydraulic circuit.

In addition, the sleeve of the pilot valve component is fixed and held only by spring force when the solenoid is OFF, making it easy to disassemble, assemble, and replace internal parts.When the opposite solenoid is ON, the pilot hydraulic pressure is output. When the solenoid is turned on, it is firmly fixed and held by the increase in spring force due to compression of the main spring, so even if the pilot oil pressure increases or vibrations or shocks are applied, the positional relationship between the pilot spool and the sleeve will be maintained. will not shift, so
Control operations can always be performed reliably without causing chatter or the like.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the left half of a conventional pilot type proportional solenoid valve, and Fig. 2 is a longitudinal sectional view of the left half of the pilot type proportional solenoid valve, which is an embodiment of the invention. Figure 3 is the entire hydraulic circuit diagram. 1... Main valve part, 2... Pilot valve component part, 3
... Solenoid component, 11 ... Main body,
12... Main spool, 13... Rod, 21
...Sleeve, 22 ...Pilot spool, 2
4...Feedback spring, 32...Solenoid coil, 34...Fixed core, 35...Movable piece, 36...Manual pump rod, 40,
47, 48...O-ring, 43...main spring.

Claims (1)

[Claims for Utility Model Registration] A pilot-type proportional electromagnetic valve is equipped with a pair of pilot valves driven by solenoids on both sides of the main valve, and the main valve is driven by pilot hydraulic pressure guided through each pilot valve. In the valve, a fixed core is fixed in a core tube having a solenoid coil on the outside, and a movable piece is installed inside each of the fixed cores of a pair of solenoid components, each of which has a movable piece of magnetic material inside so as to be able to slide slightly. A pilot valve component comprising a pilot spool driven by a sleeve and a sleeve into which the pilot spool is slidably fitted and which forms three ports whose connection relationship can be switched by sliding is housed. At the same time, each core tube of each solenoid is provided with a fitting part with the main valve part at an end to which the fixed core is fixed, and each of the fixed cores has a large diameter hollow part on the fitting part side and the movable part. A stepped hollow part is formed with a small-diameter hollow part on the side facing the piece, and the sleeve of the pilot valve component is fitted into the large-diameter hollow part, and the pilot spool is brought into contact with the movable piece through the small-diameter part. a large diameter hollow part of the fixed iron core is partitioned by an end wall of the sleeve, and an oil chamber is formed on the open end side of the sleeve to sandwich the main valve part and receive the pilot hydraulic output of the pilot valve component on the opposite side;
A C port formed in the sleeve for obtaining a pilot hydraulic output, a P port to be connected to a pump, and a T port to be connected to a tank are connected to each oil passage formed in the fixed iron core, and a core tube of each solenoid is connected to each oil passage formed in the fixed iron core. The pair of solenoid components are directly connected to both sides of the main valve part by attaching an O-ring to the outer periphery of the fitting part and fitting them into the recesses provided on both end faces of the main body of the main valve part, respectively. Connecting the oil passages of the P port and T port formed on each fixed iron core to the oil passages of the P port and T port formed on the main body, respectively,
The oil passages of the C ports formed in the fixed iron cores of the respective solenoid components are connected to the oil chamber of the solenoid component on the opposite side with the main valve section in between, and the main spool of the main valve section is connected to the oil chamber. A main spring is interposed between the end wall of the sleeve of each pilot valve component and the main body and main spool, and is inserted into the center hole of the main spool so that the main spring is aligned with the main spool. Both ends of a rod that moves in the same direction pass through the end wall of the sleeve of each of the pilot valve components, and a feedback spring is interposed between each end of the rod and each of the pilot spools. Features a pilot type proportional solenoid valve.