JP2560640Y2 - Pilot operated solenoid proportional valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot type proportional solenoid valve suitable for remotely controlling a swing hydraulic motor or a boom cylinder of a construction vehicle.

[0002]

2. Description of the Related Art A conventional pilot type solenoid proportional valve of this type is, for example, as shown in FIG.

[0003] This pilot type proportional solenoid valve has a body 4
0, P port, A port and B port, Ta port and T
A b port and an L port are provided. For each of these ports, the P port is a hydraulic oil port connected to a hydraulic pressure source,
The A port and the B port are output ports connected to a load such as a cylinder, the Ta port and the Tb port are tank ports connected to a tank, and the L port is a sensing port for detecting hydraulic pressure supplied to the A port or the B port. is there.

A sliding hole 41 penetrating through the center of the body 40 and communicating with each of the ports is formed. A main spool 42 as a valve is inserted into the sliding hole 41. The cover 4 is fixed to both ends of the cover 43 so as to project into a spring chamber 44.
5 to give a habit of returning to the illustrated neutral position.

In the cover 43, a pilot spool 46 and a pilot valve component part 47 including a valve seat (Pp is a pilot hydraulic port, Tp) are provided on the extension of the main spool 42 in a direction orthogonal to the extension. Is a tank port, Pc is a control port), and a pilot solenoid 48 for driving the pilot spool 46 is also attached. However, FIG. 4 does not show the left cover, the pilot valve component, and the pilot solenoid.

[0006] Any of the pilot solenoids 4
When the power is not supplied to the port 8, the main spool 42 is at the neutral position shown in the figure, and all the ports of the body 40 are blocked. From this state, if the right pilot solenoid 48 is energized, the pilot spool 46 descends according to the current value, and pilot oil is supplied to the control port Pc communicating with the spring chamber 44, and the hydraulic pressure causes the main spool 42 Is slid to the left against the urging force of the left spring (not shown).

As a result, the port between the P port and the B port is opened, and the pressure oil is supplied from the B port to the load.
Open between port and port A, return oil from load is A
Return from port to tank through Ta port. At this time,
The L port communicates with the B port through an oil passage 42a and radial through holes 42c and 42d in the main spool 42, and a remote control port of a pressure compensating valve whose hydraulic pressure is interposed between a hydraulic source (not shown) and the P port. , The differential pressure between the P port and the B port is controlled to be constant regardless of the flow rate.

When the left pilot solenoid (not shown) is energized, the main spool 42 is slid to the right by the pilot oil pressure corresponding to the current value, the port between the P port and the A port is opened, and the pressure oil is supplied to the A port. From the Tb port to the B port at the same time, the return oil from the load returns from the B port to the tank through the Tb port.

At this time, the L port is connected to the oil passage 4 in the body 40.
9 communicates with the A port through an oil passage 42b and radial through holes 42e and 42f in the main spool 42, and guides the oil pressure to the remote control port of the above-described pressure compensating valve, whereby the difference between the P port and the A port The pressure is controlled to be constant regardless of the flow rate. In the neutral position, the L port is connected to the through hole 42c or 42f, 42d or 42e, and the oil passage 42a or 42b in the main spool.
Through to the Ta port or Tb port.

[0010]

However, in such a conventional electromagnetic pilot proportional valve, the sensing ports La and Lb are provided at both ends of the body 40, and these are connected to one L port in the body. Therefore, it is necessary to form a long connecting oil passage 49 parallel to the sliding hole 41,
It was difficult to reduce the size of the body, and the number of holes required increased the cost.

The valve shown in FIG. 4 has a structure in which the sliding direction of the main spool 42 when the valve is opened and the direction in which the pressure oil flows from the P port to the B port or the A port are reversed. This method (same structure) is easily affected by fluid vibration. Further, it is not easy to compensate for the fluid force by changing the shape of the spool and the like, and it is not preferable in terms of component structure (machining) such as lack of control stability and a large number of body resettings.
Very few are used in general solenoid valves and proportional valves.

Further, the main spool 4 in the cover 43
Since the pilot valve component 47 is provided on the extension line of 2, the spring chamber 44 cannot be made large in view of the compact design of the valve. Therefore, a spring having a sufficient spring force cannot be incorporated as the return spring 45. Not only is it difficult to measure a high pressure and a large flow rate, but also there is a problem in improving control rigidity and responsiveness. Alternatively, it is extremely difficult to attach a detector (LVDT) for detecting a stroke of the main spool or an emergency manual operation lever on an extension of the main spool 42.

The present invention has been made in view of these problems, and a first object of the present invention is to simplify formation of a sensing port in an electromagnetic pilot proportional valve to facilitate downsizing and cost reduction of the valve. A detector (LVDT) that detects the stroke of the main spool by forming a large sprink chamber inside the cover attached to both ends of the body so that a strong return spring can be incorporated.
A second object is to make it easy to attach an emergency manual operation lever.

[0014]

In order to achieve the above object, the present invention provides a pressure oil port P, a pair of output ports A and B on both sides thereof, a pair of tank ports Ta and Tb, and one sensing port on one side thereof. A body formed with a sliding hole communicating the port L with each of these ports, a main spool fitted into the sliding hole and controlling opening and closing of each port;
A pair of covers mounted on both ends of the body and each having a spring chamber, and each port is interposed between each end of the main spool and each cover in each spring chamber, and the main spool is provided with each port. A pilot-type electromagnetic device comprising: a spring for giving a return behavior to a neutral position to be blocked; and a pair of electromagnetic pilot valves attached to each of the covers and controlling a supply amount of pilot oil into the spring chamber according to an input current. The proportional valve is configured as follows.

That is, a land portion is formed on the main spool at a position where the pair of output ports A and B are closed at the neutral position, and a small-diameter portion is formed at a position where the pressure oil port P is always open. In the neutral position, the sensing port L communicates with one of the tank ports through the center hole, and the pressure oil port P is connected to the pair of output ports A and B at the neutral position.
When it slides to communicate with any one of the above, the sensing port L is configured to communicate with the output port through the center hole.

Furthermore, it is preferable that the pair of electromagnetic pilot valves be attached to the side of the spring chamber of the pair of covers. Also, it is desirable to use, as each of the electromagnetic pilot valves, one in which a pilot valve component is housed in a fixed iron core fixed in a core tube having a solenoid coil sheathed.

[0017]

With the above construction, when the main spool slides from the neutral position by the pilot oil pressure supplied by the operation of the electromagnetic pilot valve, the sliding direction and the pressure oil port P are set. And the flow direction of the pressure oil flowing out to one of the pair of output ports A and B is in the same direction, so that it is less susceptible to fluid vibration and stability in control can be obtained.

When the valve is opened, the sensing port L
Communicates with the output port A or B through which the pressure oil flows out through the center hole of the main spool, so that there is no need to form an oil passage for connecting the two sensing ports to the body. Therefore, the formation of the sensin port is simplified,
This makes it easy to reduce the size and cost of the valve.

Further, since each electromagnetic pilot valve is attached to the side of the spring chamber of each of the covers, a large sprink chamber can be formed in the cover.
It is possible to increase the flow rate and improve control rigidity and responsiveness.

Further, it is possible to easily attach a detector (LVDT) for detecting the stroke and an emergency manual operation lever on the extension of the main spool. If the pilot valve component is housed in a fixed iron core fixed in a core tube with a solenoid coil as an electromagnetic pilot valve, the above-described operation is more effective.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a plan view of a pilot type solenoid operated proportional valve showing one embodiment of the present invention, and FIG. 1 is a sectional view taken along the line XX (however, each port is not formed at the same sectional position. FIG. 3 shows a cylinder as a load, a tank,
FIG. 5 is a hydraulic circuit diagram when hydraulic pressure sources are connected via pressure compensating valves.

As shown in FIGS. 1 and 2, the pilot-type solenoid proportional valve has a body 1, a pair of covers 2, 2 mounted on both ends thereof, and a pair of covers 2, 2 mounted on the covers 2, 2, respectively. The electromagnetic pilot valves 3 are provided. The body 1 is provided with an output port A and a port B connected to a load on the upper side, and a P port as a pressure oil port, a Ta port and a Tb port as a tank port, and a sensing port on the lower side. A certain L port and a pair of pilot ports Ppa and Ppb are provided.

As shown in FIG. 1, a sliding hole 4 penetrating through the central portion of the body 1 and communicating with each of the ports is formed, and a main spool 5 serving as a valve body is fitted therein. Both end portions are projected into spring chambers 6 and 6 formed in the covers 2 and 2, and are urged by two concentric coil sprinklings 8 and 9 from both sides via centering washers 7 respectively. The behavior of returning to the neutral position shown in the figure is given.

The main spool 5 has the lands 5a and 5b at the neutral position shown in FIG. 1 at positions where the A and B ports are closed, and the small diameter portions at positions where the P port, Ta port and Tb port are always open. And a plurality of tapered grooves are formed on each of the land portions 5a and 5b on both left and right sides thereof at circumferential intervals as shown by broken lines, so that the valve opening at a minute flow rate is also stabilized. I can do it.

Further, a center hole 5c is formed in the main spool 5 so as to penetrate along the axial direction, and both ends thereof are closed by blind plugs 11,11. In FIG. 1, a small diameter portion provided between the large diameter portions near the right end portion is provided with a through hole 5d communicating from the outer periphery to the center hole 5c, and through a sliding hole 4 and a sensing port hole 12 formed in the body. , L ports communicate with the center hole 5c.

On the other hand, an annular groove 5e and a through hole 5f communicating therefrom with a center hole 5c are formed in a large diameter portion near the left end of the main spool 5 as shown in FIG. The opening 1 is located at a position corresponding to the annular groove 5e.
A drain hole 13 having 3a is formed on the body 1 side so as to communicate with the Ta port.

The land 5 of the main spool 5
The annular portions 5g and 5h and the through-holes leading to the central hole 5c are also formed in the overlap portion on the P port side (the right side in the figure) and the overlap portion on the P port side (the left side in the figure) of the land portion 5b. Holes 5i and 5j are formed. Reference numeral 14 denotes an oil passage for communicating the tank ports Ta and Tb within the body 1, but this is not necessarily provided.

These constitute the main valve section 10. Further, electromagnetic pilot valves 3 (SOL.A, SOL.B) respectively connect a part of the core tube 31 to the upper side of each of the spring chambers 6 of the covers 2 and 2 attached to both ends of the body 1. It is fitted and attached. As the electromagnetic pilot valve 3, for example,
It is preferable to use a type in which a pilot valve component is housed in a core tube as seen in Japanese Patent Application Laid-Open No. 2-27681.

That is, the coil housing 34 provided with the solenoid coil 32 and the terminal 33 in the core tube 31.
A movable iron core (not shown) is movably incorporated in the core tube 31 and a fixed iron core 35 is fixed therein. A pilot spool (not shown) (moved by a push rod provided on the movable iron core) and A pilot valve component comprising the sliding hole (valve seat) and each port is housed.

Reference numeral 36 denotes control ports Pca and Pcb from which pilot oil is output, and communicates with the spring chamber 6 through a pilot oil passage 15 formed in the cover 2. Reference numeral 37 denotes an oil passage for supplying pilot oil, which communicates with the pilot ports Ppa and Ppb through an oil passage 16 in the cover 2 and an oil passage 17 in the body 1. Reference numeral 38 denotes an oil passage returning to the tank, which communicates with the tank port Ta or Tb of the body 1 through the oil passage 18 in the cover 2 and the oil passage 19 in the body 1.

When a pilot-type solenoid proportional valve (indicated by a dashed line in FIG. 3) configured as described above is used, as shown in FIG.
, A line for supplying pressure oil to the P port is connected, the L port is connected to the remote control (vent pressure) port Rc of the pressure compensating valve 21, and the tank port T
a and Tb are connected to the tank 22. A pilot line for supplying pilot oil from the inlet side (a) or the outlet side (b) of the pressure compensating valve 21 is connected to the pilot ports Ppa and Ppb. On the other hand, the output ports A and B are connected to the front and rear chambers of the cylinder 24 that drives the load 23, respectively.

Next, the operation of this embodiment will be described. When power is not supplied to the solenoid coil 32 of either the left or right electromagnetic pilot valve 3, the main spool 5 is at the neutral position shown in FIGS. 1 and 3, and all ports of the main valve portion 10 are blocked. Therefore, the A port and the B port are closed, the cylinder 24 is locked, and the piston 24a and the load 23 are immobile.

At this time, the L port of the main valve portion 10 is connected to the sensing port hole 12 of the body 1, the through hole 5d, the center hole 5c, the through hole 5f, the annular groove 5e of the main spool 5, and the drain hole of the body 1. 13 and the tank port, it communicates with the tank 22, and no hydraulic pressure is generated.

From this state, if the terminal 33 is connected to the solenoid coil 32 of the right electromagnetic pilot valve 3 (SOL.A).
When pilot electricity is supplied from the main spool 5 to the control port Pca communicating with the right spring chamber 6 in accordance with the current value ia,
Is slid to the left against the urging force of the springs 8 and 9 in the left spring chamber 6. In FIG. 3, the main valve portion 10 is located on the right side.

As a result, the lands 5a and 5b move leftward to open the space between the P port and the A port, and pressure oil is supplied from the A port to the front chamber of the cylinder 24. When opened, return oil from the rear chamber of the cylinder 24 returns to the tank 22 from the B port through the Ta port. At this time, since the flow direction of the pressure oil from the P port to the A port is the same as the moving direction of the main spool 5, there are advantages such as being less susceptible to fluid vibration and having high control stability.

Also, the left port of the main spool 5 cuts off the communication between the drain hole 13 and the annular groove 5e of the main spool 3, and the annular groove 5g communicates with the A port. Center hole 5 in spool 5
c and through-holes 5d and 5i communicate with the A port, and guide the hydraulic pressure (load pressure) to the remote control (vent pressure) port Rc of the pressure compensating valve 21 so that the differential pressure between the P port and the A port becomes A. It is controlled to be constant irrespective of the flow rate of the pressure oil flowing out of the port (proportional to the current value ia).

On the other hand, when the solenoid coil 32 of the right electromagnetic pilot valve 3 (SOL.B) is energized from the terminal 33 from the block state shown in FIG. 1 and FIG. 3, the left spring chamber 6 according to the current value ib. The pilot oil is supplied to the control port Pcb communicating with the main spool 5, and the hydraulic pressure causes the main spool 5 to slide rightward against the urging force of the springs 8 and 9 in the right spring chamber 6.
In FIG. 3, the main valve portion 10 is located on the left side.

As a result, the lands 5a and 5b move rightward to open the space between the P port and the B port, and pressure oil is supplied from the B port to the rear chamber of the cylinder 24. At the same time, the space between the Ta port and the A port is opened. When opened, the return oil from the front chamber of the cylinder 24 returns from the A port to the tank 22 through the Ta port, and the piston 24a moves so as to push the load 23 in the direction opposite to the arrow Q in FIG. At this time, B from P port
Since the flow direction of the pressure oil to the port is the same as the moving direction of the main spool 5, stable controllability is obtained because the influence of the fluid vibration is less.

Further, due to the rightward movement of the main spool 5, the communication between the drain hole 13 and the annular groove 5e of the main spool 3 is cut off, and the annular groove 5h communicates with the B port. Center hole 5 in spool 5
c and through-holes 5d and 5j, and communicates with the B port, and applies the oil pressure to the remote control port R of the pressure compensating valve 21.
c, the differential pressure between the P port and the A port becomes A
It is controlled to be constant irrespective of the flow rate of the pressure oil flowing out of the port (proportional to the current value ib).

According to this embodiment, the sensing port and the drain port on the A port side and the B port side are connected by the center hole 5c in the main spool 5 and guided to the common L port, so that they are connected on the body 1 side. It is not necessary to form a long oil passage for use, the valve can be made compact, and the processing related to the sensing becomes easy, so that the cost can be reduced.

Since the pilot valve component is not provided on the extension of the main spool 5 in the cover 2, a detector (LVDT) for detecting the stroke on the extension of the main spool 5 as shown by an imaginary line in FIG. It becomes easy to mount the valve 25 to enhance the control performance of the valve and to mount an emergency manual operation lever.

Further, since the spring chamber 6 can be made large, springs 8 and 9 for returning the main spool having sufficient spring force can be incorporated (in this example, two springs each). The capacity can be increased, control rigidity can be increased, and responsiveness and stability can be improved. These advantages are further promoted by using a type in which a pilot valve component is housed in a core tube as the electromagnetic pilot valve 3. Further, the cover 2 is made of an aluminum material, so that the weight of the valve can be reduced.

[0043]

As described above, according to the present invention, it is possible to reduce the size and cost of the pilot-type solenoid proportional valve. A detector (LVD) for detecting the stroke is provided on an extension of the main spool.
It becomes easy to mount T) to enhance the control performance of the valve, or to mount an emergency manual operation lever. Furthermore, by incorporating a spring with sufficient spring force as the spring for returning the main spool, it is possible to increase the pressure and capacity of the valve, or to increase the control rigidity and improve the responsiveness and stability. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view taken along line XX of FIG.

FIG. 2 is a plan view of a pilot type electromagnetic proportional valve showing one embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram showing an example of use of the pilot type electromagnetic proportional valve shown in FIGS. 1 and 2.

FIG. 4 is a longitudinal sectional view showing an example of a conventional pilot type electromagnetic proportional valve, omitting a left cover, a pilot valve component, and a pilot solenoid.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Body 2 Cover 3 Solenoid pilot valve 4 Sliding hole 5 Main spool 5a, 5b
Land portion 5c Center hole 5d, 5f, 5i, 5j Through hole 5e, 5g, 5h Annular groove 6 Spring chamber 7 Centering washer 8, 9 Coil spring 10 Main valve portion 11 Blind plug 12 Sensing port hole 13 Drain hole 15, 16, 18 Oil passage in cover 17, 19 Oil passage in body 20 Hydraulic source 21 Pressure compensating valve 22 Tank 23 Load 24 Cylinder 31 Core tube 32
Solenoid coil 33 Terminal 34 Coil housing 35
Fixed iron core 36 Control port P Pressure oil port Ta, Tb Tank port L Sensing port A, B Output port Ppa, Ppb Pilot port Pca, Pcb Control port

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-177601 (JP, A) JP-A-57-101108 (JP, A) JP-A-2-62405 (JP, A)

Claims (3)

(57) [Scope of request for utility model registration] 1. A pressure oil port (P) and a pair of output ports (A, B) and a pair of tank ports (Ta, T
b) a body formed with one sensing port (L) on one side thereof and a sliding hole communicating with each of the ports, and a main spool inserted into the sliding hole and controlling opening and closing of each port. A pair of covers attached to both ends of the body, each having a spring chamber, and each of the ports being interposed between each end of the main spool and each cover in each of the spring chambers. A spring that gives the habit of returning to the neutral position to block the
A pilot-type electromagnetic proportional valve attached to each of the covers and configured to control a supply amount of pilot oil into the spring chamber in accordance with an input current; A land portion at a position to block the pair of output ports (A, B), respectively.
The small-diameter portion is formed at a position where the pressure oil port (P) and the tank port (Ta, Tb) are always open, and a central hole penetrating along the axial direction is formed, and both ends thereof are closed. Then, when the sensing port (L) slides so as to communicate with one tank port through the center hole and the pressure oil port (P) communicates with one of the pair of output ports (A, B). And a pilot-type solenoid proportional valve, wherein the sensing port (L) is configured to communicate with the output port through the center hole. 2. The pilot-type solenoid proportional valve according to claim 1, wherein said pair of electromagnetic pilot valves are respectively attached to sides of said spring chamber of said pair of covers. 3. The pilot-type electromagnetic proportional valve according to claim 2, wherein each of said electromagnetic pilot valves houses a pilot valve component in a fixed iron core fixed in a core tube having a solenoid coil. valve.