JP4463028B2 - Spool valve - Google Patents

Description

  The present invention relates to a spool valve that switches a flow path by moving a spool incorporated in a valve body.

As this type of spool valve, the one described in Patent Document 1 is conventionally known, and FIGS. 4 to 6 show this conventional spool valve. This conventional spool valve is provided with a pair of actuator ports 2 and 3 in the valve body 1. The valve body 1 is provided with a supply port 4, and the supply port 4 communicates with the relay flow path 5 via a check valve v.
Although the spool 6 is slidably incorporated in the valve body 1, the spool 6 blocks communication between the supply port 4 and a pump (not shown) when the spool 6 is in the neutral position shown in the drawing. On the other hand, when the spool 6 is switched to the left or right side of the drawing, the supply port 4 is communicated with the pump, and one of the actuator ports 2 or 3 is connected via the first annular groove 7 or 8 formed in the spool 6. Communicate. At this time, the other actuator port 3 or 2 is communicated with the tank flow path 11 or 12 via the second annular groove 9 or 10 formed in the spool 6.

Therefore, when the spool 6 is switched to either left or right, the pressure oil supplied to the supply port 4 pushes the check valve v open and flows into the relay flow path 5, and from either of the relay flow paths 5, One actuator port 2 or 3 is supplied to an actuator (not shown) via one annular groove 7 or 8. The return oil from the actuator at this time flows out from the other actuator port 3 or 2 to the tank flow path 12 or 11 via the second annular groove 10 or 9.
Then, control notches 13 and 14 are formed in the first annular grooves 7 and 8 of the spool 6 as described above, and the relay flows through the control notches 13 and 14 according to the stroke of the spool 6. The passage 5 and the actuator ports 2 and 3 are made to communicate with each other so that a minute flow rate can be controlled.

  The check valve v opens and closes the seat portion 4a formed in the supply port 4 by the poppet portion 16 of the valve body 15. The valve main body 15 thus formed has a cylindrical portion 17 that is continuous with the poppet portion 16 on the tip side of the poppet portion 16. A plurality of large diameter holes 18 and a plurality of small diameter holes 19 are formed in the cylindrical portion 17. And the said small diameter hole 19 is located in the valve opening direction front of the check valve v, and the large diameter part 18 is located in the said valve opening direction back. Therefore, when the check valve v moves in the valve opening direction, that is, in the upward direction in the drawing, the small-diameter hole 19 is first opened in the relay flow path 5, and when the check valve v is further lifted, the large-diameter hole 18 becomes the relay flow path 5. It opens to.

  The check valve v configured as described above incorporates an auxiliary check valve 20 in the central portion of the valve body 15. The auxiliary check valve 20 is configured to allow only the flow from the supply port 4 to the pressure control chamber 21 of the check valve v. The pressure control chamber 21 is provided with a spring 22, and the poppet portion 16 normally closes the seat portion 4 a by the spring force of the spring 22.

  The pressure control chamber 21 communicates with the relay flow path 5 via the pilot spool valve 23. That is, when the pilot spool valve 23 is in the illustrated normal position, the opening for communicating the pressure control chamber 21 and the relay flow path 5 is maximized, and the pressure in the pressure control chamber 21 is connected to the relay flow path 5. Maintain almost the same pressure. However, when a pilot pressure is applied to the pilot spool valve 23, the pilot spool valve 23 moves against the spring 24, and the opening for communicating the pressure control chamber 21 and the relay flow path 5 is reduced. Thus, the smaller the opening for communicating the pressure control chamber 21 and the relay flow path 5, the more the pressure in the pressure control chamber 21 becomes equal to the pressure on the supply port 4 side.

Now, when the spool 6 is moved from the neutral position shown in the drawing to the left in the drawing, the supply port 4 communicates with the pump, and the relay flow path 4 and one actuator port 2 are connected via one first annular groove 7. Communicate. The other actuator port 3 communicates with the other tank flow path 12 via the other second annular groove 10.
Accordingly, the pressure oil flowing into the supply port 4 is supplied to an actuator (not shown), and return oil from the actuator is returned to a tank (not shown) via the tank flow path 12.

  When the movement amount of the spool 6, that is, the switching amount is made minute and the minute control, that is, the inching control is performed by the control notch 13, the pilot pressure is applied to the pilot chamber 25 of the pilot spool valve 23 to make the spool valve 23 spring. If it moves against 24, the pressure of the pressure control chamber 21 will rise relatively as mentioned above. If the pressure in the pressure control chamber 21 rises in this way, the rise of the valve body 15 is restricted by the pressure action, so that only the small-diameter hole 19 of the cylindrical portion 17 is connected to the relay flow path 5 as shown in FIG. Will open. Therefore, the flow rate supplied from the supply port 4 to the relay flow path 5 is also smaller than when the large-diameter hole 18 is open to the relay flow path 5. Since the flow rate supplied to the relay flow path 5 is reduced in this way, the control by the control notch 13 can be performed with the lower flow rate.

  If the flow rate supplied to the control notch 13 is small as described above, the inching control can be easily performed accordingly. For example, if the flow rate supplied to the control notch 13 is large, the differential pressure before and after the control notch 13 increases accordingly, so that the flow rate passing through the control notch 13 changes greatly with a slight movement of the spool 6. become. For this reason, the lever operation of the operator becomes delicate, and there arises a problem that it is impossible to steer unless an expert. Therefore, as described above, only the small-diameter hole 19 is opened in the relay flow path 5 to limit the flow rate supplied to the control notch 13.

  On the other hand, when the pilot pressure in the pilot chamber 25 is released to the tank pressure, the pilot spool valve 23 returns to the normal position shown in the figure by the action of the spring 24. When the spool valve 23 returns to the normal position shown in the figure, the opening for communicating the pressure control chamber 21 and the relay flow path 5 is maximized, so that the pressure in the pressure control chamber 21 is relatively lowered. When the pressure in the pressure control chamber 21 is relatively lowered in this way, the poppet unit 16 is also moved greatly. If the poppet portion 16 moves greatly, the large-diameter hole 18 of the cylindrical portion 17 opens into the relay flow channel 5 as shown in FIG. 6, so that the flow rate supplied to the relay flow channel 5 and the first annular groove 7 is The number of the small-diameter holes 19 is larger than when the small-diameter holes 19 are opened in the relay flow path 5. Accordingly, a large amount of pressure oil can be supplied to the actuator.

The above description is for the case where the spool 6 is switched to the left in the drawing. However, even when the spool 6 is switched to the right in the drawing, the small diameter hole 19 is opened in the relay flow path 5 or the large diameter hole 18 is connected to the relay flow path 5 depending on whether pilot pressure is applied to the pilot chamber 25. It is the same as when the spool 6 is switched to the left.
JP 2003-227571 A

In the conventional spool valve as described above, the maximum supply flow rate is regulated by the opening area of the large diameter hole 18. However, since the opening area of the large-diameter hole 18 depends on the size of the cylindrical portion 17 and the like, it cannot be increased without limitation. Therefore, there is a problem that the above-described maximum supply flow rate cannot be sufficiently secured.
An object of the present invention is to provide a spool valve that can be finely controlled and that can sufficiently secure a maximum supply flow rate.

The present invention incorporates a spool into a valve body having a pair of actuator ports, and communicates a supply port formed in the valve body with a pump, and the supply port is connected to a poppet type check valve incorporated in the valve body. When the spool is switched to the switching position, the relay channel is connected to one of the actuator ports, and the other actuator port is connected to the tank flow. On the other hand, the check valve has a fully closed position in which the poppet portion presses against the seat portion formed in the supply port and closes the seat portion, a control position for keeping the opening stroke small, and a large opening stroke. Presupposing a spool valve configured to stroke between the valve opening positions to be maintained A. And while presupposing the said spool valve, this invention provides the control protrusion in the front end side of the poppet part in the said check valve, and this control protrusion forms a notch in the base, and the notch A small diameter portion smaller in diameter than the seat portion and a tapered portion continuous to the small diameter portion in order from the front side to the rear side in the valve opening direction of the check valve. It closes in the fully closed position and opens when the check valve keeps the control position to communicate the supply port and the relay flow path, and the small diameter part is the seat part when the check valve keeps the open position. It is characterized in that it is configured to maintain a predetermined interval.

According to the first invention, in a state in which the check valve is maintained in the control position, the notch can minute flow rate control using, moreover, when the check valve is in the open position is sufficiently maximum flow It can be secured. Therefore, it is possible to appropriately respond when the actuator requires the maximum flow rate.
In addition, since the control protrusion of the check valve is provided with a small-diameter portion and a tapered portion, by adjusting the relative relationship between them in the design, the fluid force can be increased while ensuring the maximum flow rate required by the actuator. It can be reduced.

  In the embodiment shown in FIGS. 1 to 3, everything except the structure of the check valve V is the same as the conventional one. Accordingly, detailed description of the same components as those in the related art will be omitted, and the same components will be described with the same reference numerals. Since the check valve V is also characterized by the shape of the poppet portion 16, the others are the same as the conventional one. Therefore, with respect to the check valve V, the detailed description of the same components as the conventional one is omitted. The same components will be described with the same reference numerals.

The greatest feature of this embodiment is that a control projection 26 is formed at the tip of the poppet portion 16 of the check valve V and a notch 27 is formed at the base of the control projection 26.
That is, the control protrusion 26 is formed with a columnar convex portion 26a continuous with the poppet portion 16, and a plurality of notches 27 are formed around the columnar convex portion 26a. However, the cylindrical convex portion 26a has an outer diameter that fits the seat portion 4a, while having a slight axial length, so that the check valve V, that is, the valve body 15 is moved from the fully closed position shown in FIG. When slightly moved to the control position shown in FIG. 2, the supply port 4 and the relay flow path 5 communicate with each other through the notch 27. That is, the valve body 15 being in the control position means a positional relationship in which the supply port 4 and the relay flow path 5 communicate with each other through the notch 27.

  Further, a small-diameter portion 26b is formed continuously with the cylindrical convex portion 26a, and a tapered portion 26c is formed on the distal end side of the small-diameter portion 26b. The small diameter portion 26b is sufficiently smaller in diameter than the seat portion 4a, and when the valve main body 15 is in the valve open position shown in FIG. 3, a sufficient distance L is maintained between the small diameter portion 26b and the seat portion 4a. It is trying to be. The sufficient distance L here refers to an interval that allows a sufficient necessary maximum flow rate to flow through the actuators connected to the actuator ports 2 and 3.

  However, the sufficient distance L is determined by the relative relationship with the tapered portion 26c. That is, the tapered portion 26c is provided to reduce the fluid force when the check valve V is opened and closed, and the fluid force reducing effect varies depending on the angle and length of the inclined portion of the tapered portion 26c. . Therefore, for example, the smaller the outer diameter of the small diameter portion 26b, the shorter the length of the inclined surface in the axial direction of the tapered portion 26c. However, if the above-mentioned length of the inclined surface becomes too short, the fluid force reducing effect is almost lost.

On the other hand, as the length of the inclined surface is increased, the effect of reducing the fluid force can be expected, but now the outer diameter of the small diameter portion 26b must be increased. However, the larger the outer diameter of the small-diameter portion 26b, the smaller the interval L, and the maximum flow rate required by the actuator cannot be ensured. In this sense, the sizes of the outer diameter of the small diameter portion 26b and the tapered portion 26c are relatively determined according to the maximum flow rate required by the actuator.
In addition, although it is an absolute condition that the said small diameter part 26b maintains the space | interval L with respect to the sheet | seat part 4a, it may incline with respect to an axis line.

Next, the operation of this embodiment will be described.
Now, when the pilot pressure is applied to the pilot chamber 25 of the pilot spool valve 23 and the pressure in the pressure control chamber 21 is maintained at a high pressure, for example, the spool 6 is switched to the left in FIG. The check valve V in the closed position is moved to the control position shown in FIG. 2 by the supply pressure of the supply port 4. If the check valve V is in the control position, the supply port 4 and the relay flow path 5 communicate with each other via the notch 27. Therefore, a minute flow rate controlled by the notch 27 is supplied to the first annular groove 7.

  Further, for example, when the spool 6 is switched to the left in FIG. 1 without applying the pilot pressure to the pilot chamber 25, the check valve V in the fully closed position shown in FIG. 3 moves to the valve opening position shown in FIG. 3, and the supply port 4 and the relay flow path 5 communicate with each other through the interval L. Therefore, the maximum flow rate required by the actuator is supplied to the first annular groove 7.

When the maximum flow rate is supplied from the supply port 4 to the relay flow path 5 as described above, the pressure oil is guided along the inclined surface of the tapered portion 26c. In this way, the pressure oil flows along the inclined surface of the tapered portion 26c, so that the jet angle of the pressure oil to the relay flow path 5 is controlled, thereby reducing the fluid force. In this embodiment, the angle of the tip of the tapered portion 26c is set to 90 degrees, but the angle of the tip is also relatively determined.
It should be noted that by operating the pilot spool valve 23, the check valve V can be controlled to the control position or the valve opening position.

It is sectional drawing of a spool valve in the state where the check valve maintained the fully closed position. It is principal part sectional drawing of the state in which the check valve maintained the control position. It is principal part sectional drawing of the state in which the check valve maintained the valve opening position. It is sectional drawing of the conventional spool valve of the state in which the check valve maintained the fully closed position. It is a conventional principal part sectional view in the state where the check valve maintained the control position. It is a conventional principal part sectional view of the state where the check valve maintained the valve open position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve body 2, 3 Actuator port 4 Supply port 4a Seat part 5 Relay flow path 6 Spool V Check valve 16 Poppet part 25 Control protrusion 27 Notch L Interval

Claims (1)

A spool is incorporated into a valve body formed with a pair of actuator ports, and a supply port formed in the valve body is connected to a pump. The supply port is connected to the valve body via a poppet type check valve incorporated in the valve body. When the spool is switched to the switching position, the relay channel is communicated with one of the actuator ports, and the other actuator port is communicated with the tank channel. On the other hand, the check valve has a fully closed position in which the poppet portion presses against a seat portion formed in the supply port and closes the seat portion, a control position that keeps the valve opening stroke small, and a valve opening position that keeps the valve opening stroke large In the spool valve configured to stroke between
The check valve is provided with a control protrusion on the distal end side of the poppet portion, and the control protrusion has a notch in the base portion, and is on the tip side of the notch and in the opening direction of the check valve. From the rear to the rear, a small-diameter portion smaller in diameter than the seat portion and a tapered portion continuing to the small-diameter portion are provided in order, and the notch is closed at the fully closed position of the check valve, and the check valve maintains the control position. The spool valve is configured such that the supply port and the relay flow path are opened to communicate with each other , and the small diameter portion is configured to maintain a predetermined distance from the seat portion when the check valve maintains the open position.

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