JPS61160604A - Hydraulic control valve - Google Patents

Abstract

PURPOSE:To make highly accurate control performable, by engaging a pressure control disc with a valve body, while setting a drain disc oppositely in this pressure control disc, and connecting a stepping motor to the drain disc. CONSTITUTION:A rack 107 is tightly attached to the center of a valve body 102, and a gear part 108A of a pressure control disc 108 is engaged with this rack 107. Then, a drain disc 109 is made to be set to this pressure control disc 108 oppositely in a state of being stuck so closely and a stepping motor 110 to be driven by a digital input signal is connected to this drain disc 109. With this constitution, a travel of the valve body 102 comes to what is called a servomechanism uniquely determined by a turning angle of the stepping motor 110 so that highly accurate control is made performable in consequence.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluid control valve that employs a stepping motor that can be directly connected to a digital signal input.

[Prior Art] Conventionally, electric/hydraulic fluid control valves (for example, poppet valves or spool valves) have used analog electric/displacement output type torque motors or linear types such as force motors as input means. This is commonly used and will be explained below with reference to FIG. FIG. 4 is a sectional view showing a conventional fluid control valve that uses the above-mentioned linear torque motor as an input means to position the valve body (spool), and in the figure, reference numeral 1 indicates the valve body; This valve body 1 has ports ps, p1, P2Pd through which fluid enters and exits.
1 and Pd2 are formed, respectively. A spool 2 is housed inside the valve body 1 so as to be slidable in the left and right directions in the figure, and by sliding, each of the ports Ps,
Pl, P2 Pd1 and Pd2 are opened and closed to change the direction of fluid flow. Springs 3A and 3B are attached to both ends of this spool 2, and these springs 3A and 3B position the spool 2 in a neutral position at its initial stage.

Note that both end surfaces of the spool 2 are pressure receiving surfaces 2A and 2B on which fluid pressure acts.

Fluid passages 5A and 5B through which fluid flows are formed in the valve body 1, respectively, and these fluid passages 5A and 5B communicate with the pressure receiving surfaces 2A and 2B, respectively.

Further, control orifices 6A and 6B are installed in the fluid flow paths 5A and 5B, respectively.

Nozzles 7 are provided at the tips of the fluid flow paths 5A and 5B, respectively.
A and 7B are formed, and a flapper 8 is installed between these nozzles 7A and 7B. This flapper 8 is connected to a torque motor 9 and is held at a neutral position by a spring k. When no current flows through the torque motor 9, the flapper 8 is located at an intermediate position between the nozzles 7A and 7B as shown in the figure, and when current flows through the torque motor 9, , - selectively displaced in the left and right directions in the figure, and the nozzle 7
Either one of A and 7B is occluded.

The operation will be explained based on the above configuration. First, when no current flows through the torque motor 9, the flapper 8 is located at a neutral position due to the spring k, so that the fluid flow paths 5A and 5
The pressures Pcl and Pc2 in B are equal. Spool 2 is therefore also not displaced and is in its initial position determined by springs 3A and 3B.

Next, when current flows through the torque motor 4, the flapper 8 is selectively displaced in the left and right directions in the figure. Now if we assume that the nozzle 7A is displaced to the right in the figure, the nozzle 7A
Therefore, the back pressures in the working fluid flow paths 5A and 5B have a relationship of Pcl>Pc2. The back pressure in this relationship is caused by both pressure receiving surfaces 2A and 2B of the spool 2.
As a result, the spool 3 is displaced to the left in the figure. Due to this displacement of the spool 2, the fluid introduced from the port Ps flows into the port P2, and the fluid flows from the port P1 to the port Pd2.

On the other hand, when the flapper 8 is displaced to the left in the figure, the spool 2 is displaced to the right in the figure, contrary to what has been described above. By controlling the current flowing through the torque motor 9 in this way,
By positioning the spool 8, the port ps
It becomes possible to control the flow direction of the fluid flowing from.

[Problems to be Solved by the Invention] According to the above configuration, the current that is the input signal is an analog quantity. Therefore, in order to connect a digital signal of a computer, for example, an analog/digital converter (A
A/D converter) is required, and such an A/D converter is very expensive, resulting in increased costs. There was a need for an H position that could control the position of the spool valve or poppet valve. Furthermore, a linear current is generated by the torque motor 9 and the flapper 8 described above.

For a displacement transducer, in the case of rotational input, gear coupling is easy, and therefore resolution can be easily selected by increasing and decelerating speed. In this case, specific rotation input devices include stepping motors that rotate with high precision in fixed angle increments based on digital signals, and rotary type servo actuators, but none of the conventional low-cost and small-sized devices are available. There is a problem in that the torque is small, and even if the rotational motion is converted into linear motion using a rack gear mechanism, screw mechanism, etc., it is not possible to obtain a large force.

The present invention has been made based on the above points, and its purpose is to position a spool valve or a poppet valve with high precision using a configuration that employs a stepping motor that can be directly connected to a digital signal as an input means. The object of the present invention is to provide a fluid control valve that is capable of

[Means for Solving the Problems] That is, the fluid control valve according to the present invention includes a valve body having a plurality of ports through which fluid enters and exits, and a valve body that is slidably housed in the valve body and that controls the plurality of ports depending on the position. A valve body that opens and closes to change the flow direction of fluid, a fluid flow path formed in the valve body and communicating with a pressure receiving surface of the valve body, a rack fixed to the valve body, and a gear part on this rack. A pressure control disk that meshes with the pressure control disk, a drain disk that is secretly opposed to the pressure control disk, and a stepping motor that is connected to the drain disk and driven by a digital input signal. and a first hole formed in the pressure control disk and communicating with the fluid flow path, and a second hole formed in the drain disk and communicating with the drain side flow path. It is something to do.

[Function] That is, by controlling the rotation of the drain disk by a stepping motor and appropriately communicating the second hole formed in the drain disk with the first hole formed in the pressure control disk,
Drain the fluid in the fluid flow path and adjust the fluid pressure acting on the pressure receiving surface of the valve body to slide the valve body in the desired direction, and after sliding the desired amount, slide the rack. The rotation of the pressure control disk accompanying the rotation of the pressure control disk blocks the communicating first hole and the second hole, thereby fixing the position of the valve body.

[Effects of the invention] Therefore, since a stepping motor is used as the electric/displacement converter, direct connection with digital signals is possible.
This allows control using a computer. In this case, most of the force required to operate the valve body is due to the force of the fluid, and the stepping motor is not required to have high output and torque, making it possible to use a low-cost and small-sized stepping motor. Become. Since the amount of movement of the valve body is determined uniquely by the rotation angle of the stepping motor using a so-called servo mechanism, highly accurate control is possible. In addition, by appropriately adjusting the gear pitch of the gear portion of the pressure control disk, the amount of movement of the valve body relative to the rotation angle of the stepping motor can be changed, and the first It can also be adjusted by appropriately changing the shape of the second hole, and desired control can be achieved depending on the situation.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a sectional view of the fluid control valve according to this embodiment, and the mark @101 in the figure indicates the valve body.
A spool 102 is housed inside the spool 102 so as to be movable in the horizontal direction in the drawing, and ports A, B, and R are respectively formed therein. Fluid flows through these ports A, B, and R.

By sliding the spool 102, the ports A, B, and R are opened and closed to change the direction of fluid flow. Further, springs 103A and 103B are attached to both ends of the spool 102, respectively.
Its initial position is determined by A and 103B. A port 104 to which fluid (for example, hydraulic pressure) is supplied is formed in the valve body 101, and fluid passages 1058 and 105B communicating with this port 104 are formed.

Fluid pressure acts on pressure receiving surfaces 102A and 102B of the spool 102 via these fluid flow paths 105A and 105B. Further, the fluid flow paths 105A and 10
5B includes pressure control orifices 106A and 106B.
are installed respectively.

A rank 107 is fixed to the center of the spool 102. A gear portion 108A of a pressure control disc 108 meshes with this rack 107.

A drain disk 109 is closely opposed to the pressure control disk 108, and a stepping motor 110 is connected to the drain disk 109. Code 11 in the figure
1 indicates a flange portion on the side of the drain disk 108, and the output shaft 11 of the stepping motor 110 is attached to this flange portion 111.
The flange portion 113 on the second side is joined via bolts 114 and nuts 115. Further, the stepping motor 110 is connected to the valve body by a bolt 116, and the reference numeral 119 in the figure indicates a spacer.

As shown in FIG. 3(A), the pressure control disk 108 is formed with two holes 121 and a flow path communicating with the pressure receiving surface 102A side, and two holes 121 communicating with the pressure receiving surface 102B side. A hole 123 and a flow path are formed. On the other hand, as shown in FIG. 3(B), the drain disc 109 is formed with two holes 125 and a flow path that communicate with a drain tank (not shown). The symbol T is a port leading to the drain tank. In other words, the fluid control valve of this embodiment is
The pressure control orifices 106A and 106B, the pressure control disk 108, and the drain disk 109 cause the fluid pressure P1 acting on the pressure receiving surfaces 102A and 102B to
and P2, thereby controlling the position of the spool 102, and thus the flow direction and flow rate of the fluid.

The operation will be explained based on the above configuration. First, a case where the stepping motor 110 is not operating will be described. Fluid enters fluid flow path 10 at pressure P through port 104.
5A and 105B. Pressures P1 and P2 act on the pressure receiving surfaces 102A and 102B@ of the spool 102, respectively. At this time, as described above, the stepping motor 110 is not being driven, so the holes 121 and 123 on the pressure control disk 108 side and the hole 125 on the drain disk 109 side are cut off, so that the fluid flows through the fluid flow. It is enclosed within channels 105A and 105B, and the pressures P1 and P2 are equal. Therefore, the spool 102 remains at the initial position without being displaced.

Next, when the stepping motor 110 is driven and, for example, the drain disk 109 is rotated a predetermined amount clockwise in FIG. 3(B), the hole 121 of the pressure control disk and the hole 125 of the drain disk 109 are communicate. Due to this communication, the fluid in the fluid flow path 105A flows out through the holes 121, 125 and the port T into a drain tank (not shown).

As a result, the pressure P1 on the pressure receiving surface 102A side is reduced to
The pressure on the 02B side becomes lower than P2, and as a result, the spool 1
02 is displaced to the left in FIG. Spool 10
2 is displaced to the left, the rack 107 is also displaced to the left. Due to this displacement of rank 107, gear part 10
8A, the pressure control disk 108 rotates counterclockwise in FIG. 2(A). This rotation closes off the holes 121 and 125, and the pressure P1 on the pressure receiving surface 102A side and the pressure P2 on the pressure receiving surface 102B side become equal again, thereby fixing the spool 102 at this position. This is the rotation angle of the stepping motor 110 and the spool 101.
This indicates that the amount of displacement was accurately matched. At this time, port 104 and port B are in communication, and port A and port R are in communication.

Moreover, if the stepping motor 110 is rotated in the opposite direction to the above case, the hole 123 on the fluid flow path 105B side and the hole 1
25 are brought into communication, so that the spool 102 is displaced to the right in FIG. 1 and is fixed at that position. Therefore, port 104 is connected to port A, and port B is connected to port R.

According to this embodiment, since the stepping motor 110 is used as the electricity/displacement converter, direct connection with digital signals is possible, and control using a computer can be performed.

At this time, most of the force that operates the spool 102 is the force of the fluid, so the stepping motor 110 is not required to have a large output and large torque, and therefore a low-cost and small-sized stepping motor can be used. . Since the amount of displacement of the spool 102 is uniquely determined by the rotation angle of the pressure control disk 109, that is, the rotation angle of the stepping motor 110, it is possible to control with high accuracy. Further, the displacement amount of the spool 102 is adjusted by a gear portion 108A that meshes with the rack 107.
This is possible by selecting the pitch of the holes 121, 123 and 125, and also by appropriately changing the shapes of the holes 121, 123 and 125, so that desired control can be achieved. Furthermore, a stepping motor 110 and a pressure control disk 1
If a variable speed machine is interposed between the spool 102 and the spool 109 for one pulse of the digital input signal, the amount of rotation of the pressure control disc 109 corresponding to the rotation angle of the stepping motor 110 can be adjusted appropriately. It becomes possible to realize highly accurate control, such as being able to freely select the resolution of the amount of displacement. Also, the pressure control disk 108
Since it is installed in close contact with the train disk 109, there is extremely little fluid leakage, and when it is stationary, P2
-Pl-P (in the conventional case, P2-Pl -13
P) Powerful and fast-responsive control becomes possible.

Note that the number of holes 121, 123, and 125 formed in the pressure control disk 108 and the drain disk 19 is not limited to that in the embodiment described above, and various numbers may be considered.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing one embodiment of the present invention.
The figure is a sectional view of the fluid control valve, and Figure 2 is II-II in Figure 1.
3(A) is a sectional view along line A in FIG. 2, FIG. 3(8) is a sectional view taken along line BB in FIG. 2, and FIG. 4 shows a conventional fluid control valve. FIG. 101... Valve body, 102... Valve body, 105A. 105B...Fluid channel, 107...Rack, 108
... Pressure control disk, 109 ... Drain disk, 110
...Stepping motor, 121.123...1st
hole, 115... second hole.

Claims (1)

[Claims] a valve body having a plurality of ports through which fluid enters and exits; a valve body that is slidably housed within the valve body and opens and closes the plurality of ports depending on the position to change the flow direction of the fluid;
a fluid flow path formed in the valve body and communicating with the pressure receiving surface of the valve body; a rack fixed to the valve body; a pressure control disc meshing with the rack via a gear portion; a drain disc that is placed opposite to the disc in a confidential manner; a stepping motor connected to the drain disc and driven by a digital input signal; and a stepping motor that is formed on the pressure control disc and communicates with the fluid flow path. A fluid control valve comprising a first hole and a second hole formed in the drain disk and communicating with the drain side flow path.