JPH0723667Y2 - Flow control valve device with check valve for pilot pressure oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a hydraulic compound control valve (hereinafter simply referred to as compound control valve) for controlling the speed and direction of an actuator of a construction machine such as a hydraulic excavator, and this compound control valve. The present invention relates to a flow control valve device with a check valve for pilot pressure oil, which is installed between a control valve and a pilot valve which is remotely operated by pilot pressure oil, and particularly relates to downsizing of such a device and simplification of attached pilot piping. .

[Conventional technology]

Before describing the conventional flow control valve device with a check valve for this type of pilot pressure oil, first, the overall configuration of a hydraulic circuit in which such a device is mounted will be described. For example, in FIG. 5 showing a general hydraulic circuit of a hydraulic excavator, each actuator 10, 12, 14 provided in the hydraulic excavator is
Unit control valves 24, 26, 28 corresponding to respective actuators are provided in the composite control valve 22 which is remotely operated via pilot pressure oil generated by operating the corresponding pilot valves 16, 18, 20. The speed and the driving direction are controlled by.

In the following, control of the actuator 10 will be described as an example.First, in the illustrated state, the pilot valve 16 is in the neutral position, the pilot ports 16a, 16b are both in communication with the tank 32, and the pilot ports 16a, 16
Pilot port 2 of unit switching valve 24 connected to b
Since both 4a and 24b are at the same pressure as the tank 32, the unit switching valve 24 is also in the neutral position, and the discharge oil from the main pump 30 flows from the pump port 22a of the combined control valve 22 to the center bypass passage 22b and the tank port. It is returned to the tank 32 through 22c. Here, if the operation lever 16c of the pilot valve 16 is tilted to the left in the figure, for example, the pilot port
Pilot pressure oil of the pilot pump 34 flows into 16a, and pilot pressure proportional to the amount of the tilt angle is generated at the pilot port 16a. Then, this pilot pressure is transferred to the unit switching valve 24 via the pilot pipe 36 (36a, 36b).
The plunger 24b moves to the right side from the neutral position in the figure against the force of the spring 24c, which causes the oil discharged from the main pump 30 to move to the combined control valve.
22 pump ports 22a, parallel oil passage 22d, shaft right angle hole 22
It is supplied to the actuator 10 through the shaft center hole 22e, the check valve 22f, the shaft right angle hole 22m, and the actuator port 22g, and the actuator 10 is driven at a speed corresponding to the tilt angle of the operation lever 16c. At this time, the actuator
Return oil from 10 is returned to the tank 32 via the actuator port 22h, the shaft right angle hole 22n, the shaft center hole 22i, the check valve 22j, the shaft right angle hole o, the return oil passage 22k, and the tank port 22c. When the operating lever 16c of the pilot valve 16 is returned to the neutral position, the pilot pressure oil that has been exerting pressure on the pilot port 24a is released from the pilot pipe 36 (36a, 36a
b) Since the flow is opened to the tank 32 via the pilot port 16a, the plunger 24b of the unit switching valve 24 is returned to the neutral position by the force of the spring 24c, and thus the driven actuator 10 is stopped. Also, the operating lever
When 16c is tilted in the opposite direction to the above, that is, to the right, pilot pressure oil from the pilot pump 34 acts on the pilot port 24d via the pilot port 16b and pilot piping 38, and the plunger 24b moves to the left side, causing the actuator to move. 10 is driven in the opposite direction to the above.

However, in such a construction machine, when the actuator suddenly stops, a shock (a sudden stop shock) is generated in the cab and the comfortability is impaired. In recent years, therefore, the flow rate with a check valve for preventing such a sudden stop shock has been reduced. Control valve
40 (indicated by the one-dot chain line in Fig. 5) has been developed and applied. As shown in FIG. 5, the flow rate control valve with a check valve (hereinafter sometimes simply referred to as a control valve) 40 is composed of a check valve 42 and a flow rate control valve 44. Pilot piping 36a and 38a for both ports
... and 36b, 38b ... but this control valve 4
The configuration of 0 will be described.

In FIG. 4, the control valve 40 is composed of a check valve 42 and a flow rate control valve 44 which are arranged in parallel, and the check valve 42 and a check poppet 46 that blocks passage of pressure oil from the B port to the A port. With check sheet 48, flow control valve
44 includes an orifice 50, a flow rate control spool 52 that controls the flow rate through the orifice 50 to a predetermined flow rate, and a flow rate control spring 64. And in such a configuration,
Pilot pressure oil flowing from the pilot valve 16 into the A port via the pilot pipe 36a passes through the chamber 54 and the oil passage 56, opens the check poppet 46 of the check valve 42, reaches the oil passage 58, and freely flows to the B port. . At this time, a part of the pilot pressure oil in the chamber 54 merges into the oil passage 58 through the orifice 50, the chamber 60, and the flow control valve oil passage 62, but this flow amount has a small opening area of the orifice 50. Therefore, the flow rate is extremely small compared to the flow rate flowing through the check valve 42. Further, the pilot pressure oil that has flowed into the B port from the pilot port 24a through the pilot pipe 36b is, on the one hand, the oil passage 58.
Flows into the check poppet 46 through the small hole 46a, presses the check poppet 46 toward the check sheet 48 side, and closes the check valve 42.
The pressure oil inside is flow control oil passage 62, chamber 60, orifice 50, chamber
Flow through 54 to A port. However, at this time, when the flow rate flowing through the orifice 50 reaches a predetermined control flow rate, a predetermined pressure difference is generated in the orifice 50, which causes the flow control spool 52 to move in the drawing due to the high pressure in the chamber 60 on the upstream side of the orifice 50. It is pushed and moved to the left.

The predetermined pressure difference is predetermined so as to be a value obtained by dividing the force of the flow rate control spring 64 by the sectional area of the flow rate control spool 52. Therefore, when pilot pressure oil of a predetermined flow rate or more is going to flow through the orifice 50,
The flow rate control spool 52 moves to the left in the figure, and the space between the flow rate control oil passage 62 and the annular oil passage 52a of the flow rate control spool 52 is blocked.
A from B port to A without flowing from port to A port
The flow rate of pilot pressure oil to the port is controlled to a predetermined flow rate.

Therefore, in the pressure oil circuit including such a control valve 40, the pilot valve 16 is driven to drive the actuator 10.
When the operating lever 16c of is tilted to the left, the total flow rate of the pressure oil discharged from the pilot pump 34 is changed to the pilot port 2 via the pilot pipe 36a, the control valve 40, and the pilot pipe 36b.
Since it flows into 4a and the plunger 24b is operated at high speed,
The actuator 10 can be driven with a short response time. On the other hand, when the operating lever 16c of the pilot valve 16 is rapidly returned to the neutral position when the actuator 10 is driven at high speed, the pressure oil in the chamber 24f connected to the pilot port 24a is set to a predetermined value through the control valve 40. Since it is recirculated into the tank 32 at a flow rate of, the return speed of the plunger 24 to the neutral position is also controlled to a predetermined speed, the actuator 10 does not suddenly stop, and therefore a sudden stop shock does not occur.

[Problems to be solved by the device]

However, the above-mentioned flow control valve with check valve has the following drawbacks.

That is, in a construction machine such as a hydraulic excavator, a large number of hydraulic devices are arranged in a limited space, and these devices are connected to each other by pipes. When arranging the attached flow control valve and its connecting piping, the flow control valve with check valve is generally required for all actuators and its shape is relatively large and cannot be directly incorporated in the composite control valve. It requires a new space, and at the same time, the hydraulic piping becomes more complicated and the cost increases.

Therefore, an object of the present invention is to reduce the size of the flow control valve with check valve so that it can be directly connected to an ordinary composite control valve, thereby making the entire device compact and simplifying the hydraulic piping. It is to provide a flow control valve device with a check valve for pressure oil.

[Means for Solving the Problems]

In order to achieve the above object, a flow control valve device with a check valve for pilot pressure oil according to the present invention is a composite control valve (22).
And a pilot valve (36a, 36b, 38a, 38b) communicating with the operation pressure oil control pilot valve (16), a flow control valve with a check valve (70) is connected and arranged, and the pilot valve for pilot pressure oil ( When the flow from 16) to the combined control valve (22) flows, the check valve (72) of the flow control valve with check valve (70) is opened to allow the pilot pressure oil to pass freely, and the combined control of the pilot pressure oil is performed. When flowing from the valve (22) toward the pilot valve (16), the check valve (72) is closed and the flow rate control valve (74) of the flow control valve with check valve (70) controls the flow rate of the pilot pressure oil. In a flow control valve device with a check valve for pilot pressure oil configured to control to a predetermined flow rate, the flow control valve with a check valve (70) is combined with an A port connected to the pilot valve (16) side. Connect to control valve (22) side B port and the B port are arranged on the same axis, and the flow control spool (82) forming the flow control valve (74) slides inside the check poppet (76) forming the check valve (72). It is characterized in that it is arranged freely and is directly connected to the composite control valve (22).

In this case, the flow control valve with a check valve (70) is composed of a check poppet (76) and a check seat (78) that prevent the passage of pilot pressure oil, and the flow control valve (74) ) Is composed of an orifice (80), a flow rate control spool (82) for controlling the flow rate through the orifice (80) to a predetermined flow rate, and a flow rate control spring (92), and the A port, check sheet (78), check A poppet (76) and the B port are sequentially arranged on the same axis, and a check poppet outer peripheral oil passage (84) communicating with the check sheet (78) and the B port is provided outside the check poppet (76). A flow control spool (82) is slidably arranged inside the check poppet (76), and a side wall of the check poppet (76) and a side wall of the flow control spool (82) are respectively checked. It may be configured to provided Kupopetto outer peripheral oil passage (84) and the flow control fluid passage communicating with the chamber (86) of the flow rate control spool (82) within the (88) ring-shaped oil passage and (90).

[Action]

Flow control valve with check valve is arranged on the same axis A,
B It is constructed in series between both ports. Therefore, the dimension in the direction perpendicular to the axis thereof is particularly small, and it is possible to directly connect the pilot ports of the unit switching valves, which form the composite control valve and have a narrow interval, in parallel with each other without any trouble. That is, the required space is minimized, the number of connecting pipes is reduced, and the hydraulic pipes of the entire machine are not complicated.

〔Example〕

Next, one embodiment of a flow control valve device with a check valve for pilot pressure oil according to the present invention will be described in detail below with reference to the accompanying drawings.

First of all, the overall structure of the hydraulic circuit to which the flow control valve with check valve of the present invention is mounted is completely the same as the conventional structure shown in FIG. Is omitted.

However, the flow control valve with check valve according to the present invention is configured as described below. That is, in FIG. 1, the control valve 70 is composed of a check valve 72 and a flow rate control valve 74, and the check valve 72 is provided with a check poppet 76 and a check seat 78 that prevent passage of pilot pressure oil. The orifice 74 includes an orifice 80, a flow rate control spool 82 that controls the amount of oil passing through the orifice 80 to a predetermined flow rate, and a flow rate control spring 92. Here, the A port connected to the pilot valve side and the B port connected to the composite control valve side are arranged on the same axis line, and the check sheet 78 and the check poppet 76 are sequentially arranged on the same axis line from the A port side. A check poppet outer peripheral oil passage 84 that connects the check sheet 78 and the B port is provided outside the check poppet 76, and the flow control spool 82 is provided inside the check poppet 76.
Is slidably arranged. The side wall of the check poppet 76 has a check poppet outer peripheral oil passage 84 and a flow control spool 82.
A flow rate control oil passage 88 is provided for communicating with the chamber 86 on the upstream side of the orifice via an annular oil passage 90 provided on the spool 82. The outer peripheral oil passage 84 is formed in a cocoon shape as shown in a cross section in FIG. 2, and the two are communicated with each other by an axis-perpendicular oil passage 84a. Further, the flow control oil passage 88 is moved by moving the spool 82 to the left in FIG.
The opening area between the oil passage 90 and the annular oil passage 90 is reduced, and finally, the oil passages 88 and 90 are blocked. Further, reference numerals 94, 96 and 98 respectively denote a chamber, a check spring and a chamber.

The control valve 70 of the present invention having such a structure operates basically in the same manner as the above-mentioned conventional control valve 40. That is,
The pilot pressure oil that has flowed into the A port reaches the chamber 94 and opens the check valve 72 against the biasing force of the check spring 96, and freely flows through the outer peripheral oil passage 84, the axis-perpendicular oil passage 84a, and the chamber 98.
It flows to the port. At this time, part of the pilot pressure oil in the chamber 94 merges into the outer peripheral oil passage 84 through the orifice 80, the chamber 86, the annular oil passage 90, and the flow rate control oil passage 88. Since the opening area of the check valve 72 is small, it is extremely small compared to the flow rate of the check valve 72. On the other hand, the pilot pressure oil that has flowed into the B port pushes the check poppet 76 toward the check seat 78 and then the check valve 72.
However, on the other hand, it flows from the chamber 98 to the outer peripheral oil passage 84, the flow rate control oil passage 88, the chamber 86, the orifice 80, the chamber 94, and flows to the A port. However, at this time, when the flow rate through the orifice 80 reaches a predetermined flow rate, a predetermined pressure difference is generated in the orifice 80, which causes the flow control spool 82 to move in the drawing due to the high pressure in the chamber 86 upstream of the orifice 80. It is pushed and moved to the left. Since the predetermined pressure difference is predetermined to be a value obtained by dividing the force of the flow control spring 92 by the cross-sectional area of the flow control spool 82, the pilot pressure oil of the predetermined flow rate or more passes through the orifice 80. When trying to flow, the flow control spool 82 moves to the left in the figure, and the flow control oil passage 88 and the annular oil passage of the flow control spool 82 are moved.
Since the area between 90 and 90 is blocked, pressure oil above the specified flow rate is
There is no flow from the port to the A port, and the flow rate of pilot pressure oil from the B port to the A port is controlled to a predetermined flow rate. As described above, when the actuator is driven, the total flow rate of the pressure oil discharged from the pilot pump flows into the combined control valve through the control valve 70, and the plunger 24b is operated at high speed, so that the actuator is driven with a short response time. can do. On the other hand, when the actuator is stopped, the pilot pressure oil is recirculated to the tank 32 at a predetermined flow rate set in advance via the control valve 70, so that the return speed of the plunger 24b to the neutral position is also controlled to a predetermined speed. No sudden stop shock will occur due to sudden stop of the actuator.

By the way, in the flow rate control valve 70 with a check valve of the present invention having such a configuration, the check valve 72 and the flow rate control valve 74 are configured integrally and in series. The shape, especially in the direction perpendicular to the axis, can be greatly reduced. Therefore, as shown in the drawing, the unit switching valves 24, 26, ... Of the normal composite control valve 22 can be directly connected in parallel adjacent to each other without any trouble. That is, compared with the conventional control valve connected via the pilot pipe, the required space can be reduced to the minimum, and at the same time, the connecting pipe can be simplified.

FIG. 3 shows another embodiment of the flow control valve with a check valve according to the present invention. As is apparent from FIG. 3, the control valve 100 of this embodiment has a check spring in the previous embodiment.
96 and its chamber 98 are omitted. Therefore, in the oil-free state and when the pressure at the B port is slightly higher than the pressure at the A port, the check poppet 76 and the check seat 78 are separated from each other, that is, the check valve 72 is opened.

Therefore, in this state, it seems that oil freely flows from the B port to the A port, and it is impossible to control the flow rate of the passage from the B port to the A port. stroke control pressure of the plunger of the valve 22 is about 3 kg / cm ² at the neutral position, and set the force of the spring 24 to be about 20 kg / cm ² at the stroke end, the pilot port 24a of the composite control valve 22 In the pressure range of 3 kg / cm ² or less, the plunger is in the neutral position, and therefore oil is not discharged from the pilot port 24a. In other words, it is not necessary to control the flow rate from B port to A port, so check valve
No problem if 72 is open. Further, when the pressure at the B port is 3 kg / cm ² or more, the urging force of the flow control spring 92 and the diameter of the check sheet 78 can be appropriately determined so that the check valve 72 is closed. Therefore, even if the check spring is omitted in this manner, practically no problem occurs.

The present invention has been described above with reference to the preferred embodiments, but the present invention is not limited to these embodiments, and many design changes can be made without departing from the spirit thereof.

[Effect of device]

As described above, in the pilot pressure oil flow control valve device with check valve according to the present invention, the check valve forming the control valve and the flow control valve are integrally and serially configured. Compared with the conventional flow control valve with check valve that was configured in parallel, the shape of the control valve can be significantly reduced, especially in the direction perpendicular to its axis. They can be directly connected in parallel. Therefore, the required space can be suppressed to the minimum, and at the same time, the connection pipe can be simplified.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a flow control valve device with a check valve for pilot pressure oil according to the present invention, and FIG.
Fig. 2 is a sectional view taken along line II-II, Fig. 3 is a vertical sectional view showing another embodiment of the flow control valve with a check valve according to the present invention, and Fig. 4 is a vertical sectional view showing a conventional flow control valve with a check valve. FIG. 5 is a circuit diagram showing an actuator driving hydraulic circuit of a construction machine. 22 …… Composite control valve 24,26 …… Unit switching valve 24a …… Pilot port 36a …… Pilot piping 70 …… Flow control valve with check valve 72 …… Check valve 74 …… Flow control valve 76 …… Check poppet 78 …… Check sheet 80 …… Orifice 82 …… Flow control spool 84 …… Outer peripheral oil passage 84 a …… Axial right angle oil passage 86 …… Chamber 88 …… Flow control oil passage 90 …… Circular oil passage 92 …… Flow control spring 94 …… Room 96 …… Check spring 98 …… Room 100 …… Flow control valve with check valve

Claims (2)

[Scope of utility model registration request] Claims: 1. Pilot piping (36a, 3a) for connecting the composite control valve (22) and the operating pressure oil control pilot valve (16).
6b, 38a, 38b) is connected with a flow control valve with a check valve (70), and when the pilot pressure oil flows from the pilot valve (16) toward the combined control valve (22), the flow control with the check valve is performed. The check valve (72) of the valve (70) is opened to allow the pilot pressure oil to freely pass therethrough, and when the pilot pressure oil flows from the combined control valve (22) toward the pilot valve (16), the check valve (72 ) Is closed and the flow rate control valve (74) of the flow rate control valve (70) with check valve controls the flow rate of the pilot pressure oil to a predetermined flow rate. In the flow control valve with check valve (70), the A port connected to the pilot valve (16) side and the B port connected to the combined control valve (22) side are arranged on the same axis. Configuring its check valve (72) A flow control spool (82) constituting a flow control valve (74) is slidably arranged inside the check poppet (76) to be directly connected to the composite control valve (22). A flow control valve device with a check valve for pilot pressure oil, which is characterized in that 2. A flow control valve with a check valve (70) comprising a check poppet (76) for blocking passage of pilot pressure oil and a check seat (78), the flow control valve having a check valve (72). The (74) comprises an orifice (80), a flow rate control spool (82) for controlling the flow rate of the orifice (80) to a predetermined flow rate, and a flow rate control spring (92), and the A port and the check sheet (78). , The check poppet (76) and the B port are sequentially arranged on the same axis line, and the check seat (78) and the check poppet outer peripheral oil passage (84) communicating with the B port are provided outside the check poppet (76). , A flow control spool (82) is slidably arranged inside the check poppet (76), and the side wall of the check poppet (76) and the side wall of the flow control spool (82) are respectively separated. The pilot pressure according to claim 1, further comprising: a flow control oil passage (88) and an annular oil passage (90) that connect the outer periphery oil passage (84) and the chamber (86) in the flow control spool (82). Flow control valve device with oil check valve.