JPH11311205A - Hydraulic control device with reclamation function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure safety by surely supplying pressure oil and preventing the production of cavitation. SOLUTION: An intermediate chamber 36, in which the notch section provided in a switch spool 34 opens in a pressure oil supply passage 32, and to which pressure oil is supplied from the pressure oil supply passage 32 through the notch section, is provided between the cylinder ports 38a and 38b of each switch valve and a pressure oil supply passage 32 according to the movement of the switch spool 34, and auxiliary ports 50 are provided between the tank line 47 communicated to the intermediate chamber 36 and the cylinder ports 38a and 38b to supply pressure oil to an actuator through the intermediate chamber 36 and one of the cylinder ports, and returned oil is discharged through the other cylinder port and the auxiliary port 50. In this case, a flow control means 48 is provided in an oil passage from the auxiliary port 50 to the tank line to adjust the flow rate in an opening direction by means of the pressure in the intermediate chamber 36 and in a closing direction by means of external signal pressure, and check valves 42 and 72 are arranged and connected in the direction to prevent the flow of pressure oil to the auxiliary port 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device such as a hydraulic excavator applied to construction machines and the like, and more particularly to an operation of an actuator which has a regeneration and counter balance function on a hydraulic circuit and is to be meter-out controlled. sex,
The present invention relates to a hydraulic control device having a regeneration function capable of improving safety and productivity.

[0002]

2. Description of the Related Art The applicant of the present invention has previously described a hydraulic control device for a construction machine such as a hydraulic shovel or the like during a composite operation.
In proportion to the opening area of the variable orifice between the pressure oil supply line and the actuator line of each switching valve, the discharge flow rate of the hydraulic pump is proportionally distributed so that good combined operability is obtained, and due to fluctuations in working conditions, When the pressure of the return oil becomes higher than the supply pressure oil in a specific actuator, the return oil having high energy is returned to the pressure oil supply passage side by the action of the regeneration check valve to save energy and improve work efficiency. And a cavitation is prevented, and a regeneration hydraulic circuit having a relatively simple and compact configuration has been developed, and a patent application has been filed (JP-A-4-185903).

[0003] That is, the hydraulic circuit according to the proposal has a configuration shown in FIGS. 5 to 7. 5 to 7, reference numeral 112 denotes a boom actuator, 11
Reference numeral 4 denotes an arm actuator. In this case, the arm actuator 114 is specified, and the regeneration check valve 162 is connected to the unit return line 150 and the unit supply line 1 of the switching valve 136 with respect to the arm actuator 114.
26 is provided in a passage communicating with the line 26.
From line 50, pressurized oil flows to line 126,
6 to line 150 are configured to block the flow of pressurized oil. Also, an orifice 164 and a check valve 166 are provided between the maximum signal pressure line 144 and the tank line 132, and the check valve 166 allows pressure oil to flow from the line 132 to the line 144, and the line 144 to the line 132. Is configured to block the flow of pressurized oil.

In FIG. 5, the structure of the switching valve 136 is such that the oil passage 170 connected to the pump line 118 is connected to the unit supply line 126 via the load check valve 122.
And a pilot port 172 is connected to the highest signal pressure line 144, and the unit signal pressure line 140 is connected to the hole 174 and each unit signal pressure line 140.
a, 140b via oil chambers 158a, 160, respectively.
a through the ball check valve 182, the pilot line 172b, and the orifice 180a.
66b.

On the other hand, the auxiliary spools 178, 180 of the auxiliary valves 158, 160 are connected to oil chambers 158a (160a) at both ends.
When the pressure of the oil chamber 158b (160b) is equal to the pressure of the oil chamber 158b (160b), the unit return line 150 (152) and the tank line 132 communicate with a large opening as shown by the spring force of the relatively small spring 190 (191). Holds open position. When the main spool 176 is at the neutral position, the unit signal pressure line 140
Right and left two shaft right holes 176a, shaft center holes 176b, shaft right holes 176c and unit return lines 150, 152, and annular oil passages 158d, 160d of auxiliary valves 158, 160.
Through the tank line 132. When the main spool 176 moves to the left side in the drawing, the unit supply line 126 is connected to the cylinder port 13 via the right orifice 176d on the outer periphery of the main spool 176 in the drawing.
6b, while the cylinder port 136a communicates with the unit return line 150 via a notch 176e on the outer periphery of the main spool 176 on the left side of the drawing.

The pilot port 172 communicates with oil chambers 158b and 160b via a pilot line 172a and an orifice 178a and a pilot line 172b and an orifice 180a, respectively.
The ball check valve 182 is configured to open when the pressure of the unit signal pressure line 140 is higher than the pressure of the highest signal pressure line 144 connected to the pilot port 172 and close when the pressure is low.

In the configuration shown in FIG. 7, the regeneration check valve 162 shown in FIG. 6 is provided between the unit return line 150 and the supply side actuator line 130b for the arm actuator 114. With such a configuration, when the switching valves 134 and 136 are operated to the positions (a) and (b), respectively, and the two actuators 112 and 114 are simultaneously operated, the unit of the arm actuator 114 is When the pressure in the return line 150 becomes higher than the pressure on the pressure oil supply line side, the return oil in the high-pressure unit return line 150 opens the regeneration check valve 162 and is directly returned to the actuator line 130b, and the arm actuator 114 Only speed up. Accordingly, in this case, unlike the configuration shown in FIG. 6, the speed of the boom actuator 112 is not increased.

Therefore, in the conventional hydraulic circuit configured as described above, a plurality of actuators having different load pressures are driven by the discharge oil from a common hydraulic pump, and the unit return line of each switching valve and An auxiliary valve for limiting the degree of opening is provided between the tank and the tank line. For a specific actuator, between the unit return line and the hydraulic oil supply line, the hydraulic oil in the return line is By providing a regeneration check valve that recirculates to the supply line, the amount of oil supply to the low-load side actuator is limited by the action of the auxiliary valve, and a plurality of actuators having different load pressures can be reliably operated simultaneously. In addition, depending on working conditions, high-pressure return oil is returned to the supply line via the regeneration check valve, thereby saving energy in the hydraulic circuit. Those that can improve the work efficiency and operability in rabbi.

[0009]

However, in the above-mentioned prior art, various problems to be improved remain.

That is, in the prior art, an auxiliary port 150 is provided on an oil passage through which pressure oil is discharged from the cylinder port 136a to the tank line 132, and an oil passage from the auxiliary port 150 to the tank line 132 is provided. Flow rate adjusting means 158 is provided. Further, the pressure of the cylinder port 136a acts on the flow rate adjusting means 158 in the opening direction, and the highest pressure of the load pressure of the actuator connected to each switching valve is selected and acts on the flow regulating means 158 in the closing direction. ing. However, in this case, since the pressure for controlling the opening and closing of each flow rate adjusting means is supplied through the signal path provided in the switching spool of each switching valve, the pressure loss in the path leading to each flow rate adjusting means is reduced. And
It is affected by leakage of signal pressure oil at each sliding part. Therefore, the operation of the flow rate adjusting means becomes unstable depending on a change in the environmental temperature in which the hydraulic device is used, and there is a problem that an appropriate regeneration function cannot always be obtained.

In the structure of the switching valve shown in FIG. 5, the pressure of the pressure oil supply line 170 of the hydraulic pump always acts on the regeneration check valve 162 via the check valve 122. Whenever another actuator is operated, the pressure of the pressure oil supply line fluctuates each time. Therefore, the reliability of the configuration of the regeneration passage is required to be further ensured.

Further, in the above-mentioned prior art, FIG.
As shown in FIG. 5, the regeneration check valve 162 is directly connected to the cylinder port of the switching valve to be regenerated. In this case, unlike the switching valve structure shown in FIG. However, since the pressure oil in the cylinder port acts directly on the regeneration check valve 162, it is necessary to take sufficient care to prevent leakage of the pressure oil in the neutral state.

On the other hand, in the above-mentioned prior art, when the switching valve having the regeneration function is operated alone, the control pressure in the opening direction and the closing direction of the flow rate adjusting means 158 of this switching valve are both changed by the switching valve. And therefore the flow control means is held in the open position.
In this case, for example, when the rotation speed of the hydraulic pump that supplies the pressure oil to the hydraulic device is small, and, for example, the spool 176 is operated to the left in the configuration shown in FIG. 5, the return oil of the cylinder port 136a becomes the notch 176e , Auxiliary port 1
50, the oil is discharged to the tank line 132 through the oil passage 158d. The notch 176e is set to be relatively large in accordance with the supply oil amount when the rotation speed of the hydraulic pump is rated.
In addition, since the spool 178 of the flow rate adjusting means 158 is kept at the open position, the pressure oil in the return line 130a of the arm actuator 114 is released from the load 114a.
And 114b are rapidly discharged by its own weight drop. As a result, as described above, the amount of oil supplied from the hydraulic pump is insufficient, and accordingly, the amount of oil in the supply line 130b connected to the cylinder port 136b is insufficient, and cavitation occurs in the actuator 114, and this operation is performed. It can be very difficult. In order to prevent the occurrence of the cavitation, the opening of the notch 176e may be limited in advance, but in this case, the resistance is large with respect to the supply oil amount when the rotation speed of the hydraulic pump is rated. Therefore, there is a difficulty that a predetermined actuator speed cannot be obtained.

The inventor of the present invention has made intensive studies and studies and, as a result, has connected a control valve having a plurality of switching valves to the hydraulic pump, and connected an actuator to each of the switching valves, thereby obtaining the switching valves. , A hydraulic control device is configured to supply and discharge hydraulic oil from the hydraulic pump to each actuator, and each of the switching valves is slidably supported in a valve body in a liquid-tight and slidable manner. When,
A plurality of oil passages which are communicated or blocked according to the position of the switching spool of the switching valve, a pressure oil supply passage for supplying pressure oil from the hydraulic pump to the oil passage, and a communication with the pressure oil supply passage. According to the movement of the switching spool between the cylinder port and the cylinder port and the pressure oil supply passage, a cutout portion provided in the switching spool opens to the pressure oil supply passage and the pressure oil supply is performed through the cutout portion. When an intermediate chamber to which pressure oil is supplied from a passage, a tank line communicating with the intermediate chamber, and an auxiliary port provided between the tank line and the cylinder port, and when the switching valve is operated, The pressure oil is supplied to the actuator from the pressure oil supply passage through the intermediate chamber and one of the cylinder ports, and the other cylinder port and the auxiliary port are supplied from the actuator to the other cylinder port and the auxiliary port. To return to the tank line through to discharge the oil, further provided a flow rate adjusting means on the oil path from the auxiliary port to the tank line, the oil path between the auxiliary port and the tank line, the flow rate adjusting means While adjusting in the opening direction by the pressure of the intermediate chamber, and adjusting in the closing direction by the external signal pressure, and in the oil passage from the auxiliary port and the intermediate chamber to the cylinder port, from the oil passage to the auxiliary port The check valve is connected and arranged in the direction to block the flow of
In addition to supplying hydraulic oil to each actuator connected to each switching valve and having a different load pressure at the same time and in accordance with the operation amount of each switching valve, cavitation can be performed even when operating a load that falls by its own weight. , And maintain a predetermined speed for each actuator.Additionally, a counterbalance function can be added.Furthermore, operability and safety can be improved regardless of the oil supply amount of the variable displacement pump. It has been found that the fixed price of the speed can be prevented and the productivity can be improved.

Accordingly, an object of the present invention is to reliably supply hydraulic oil to the cylinder port of each switching valve when a plurality of switching valves having different loads are operated simultaneously when applying to construction machines and the like. It is another object of the present invention to provide a hydraulic control device capable of preventing the occurrence of cavitation as well as easily ensuring operational safety.

[0016]

In order to achieve the above object, a hydraulic control device having a regeneration function according to the present invention comprises connecting a control valve having a plurality of switching valves to a hydraulic pump, and connecting each of the switching valves to the hydraulic pump. In a hydraulic control device configured to supply and discharge pressure oil from the hydraulic pump to each actuator by connecting an actuator and operating each of the switching valves, each of the switching valves is liquid-tight within a valve body. And a slidably supported switching spool, a plurality of oil passages which are communicated or shut off in accordance with the position of the switching spool of the switching valve, and pressure oil for supplying pressure oil from the hydraulic pump to the oil passage. A supply passage, a cylinder port communicating with the pressure oil supply passage, and a switching port provided between the cylinder port and the pressure oil supply passage in accordance with movement of the switching spool. A notch opening into the pressure oil supply passage, an intermediate chamber to which the pressure oil is supplied from the pressure oil supply passage via the notch, a tank line communicating with the intermediate chamber, the tank line and the cylinder port When the switching valve is operated, the hydraulic oil is supplied from the hydraulic oil supply passage to the actuator through the intermediate chamber and one of the cylinder ports. It is configured to return the oil to the tank line via the other cylinder port and the auxiliary port, and to discharge the oil.Furthermore, a flow rate adjusting means is provided on an oil passage from the auxiliary port to the tank line. The flow path adjusting means adjusts the oil path in the opening direction by the pressure of the intermediate chamber and adjusts the oil path in the closing direction by the external signal pressure. Moreover the oil path leading to the cylinder port from the auxiliary port and the intermediate chamber, characterized in that connecting place a check valve in a direction to block the flow to the auxiliary port of the oil passage.

In this case, the external signal pressure for adjusting the flow rate adjusting means in the closing direction can be the pressure of the intermediate chamber of another switching valve.

Further, the pressure in the intermediate chamber of each of the switching valves is detected, the maximum pressure among these pressures is selected, and corresponding to this maximum pressure, the flow rate adjusting means of the switching valve is used as an external signal pressure. It can be configured to exert hydraulic pressure.

Further, another pilot signal pressure may be supplied to the supply line of the external signal pressure acting on the flow rate adjusting means of each of the switching valves via a check valve.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a hydraulic control device according to the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1 FIG. 1 shows an embodiment of a hydraulic control device according to the present invention. That is, in FIG. 1, reference numeral 30 denotes a valve body. The valve body 30 includes a common pressure oil supply passage 32 for receiving the supply of pressure oil from the variable displacement pump P, a switching spool 34, and a switching spool 34. An intermediate chamber receiving the supply of the pressure oil from the pressure oil supply passage 32 by the movement of the cylinder oil, a cylinder port 38a, 38b, a passage 40, 40 from the intermediate chamber 36 to the cylinder port 38a or 38b, a check valve, 42 and the switching spool 3
The auxiliary ports 44, 44 and the tank line 47 for discharging the pressure oil of the cylinder port 38a or 38b to the tank T by the movement of the tank 4 are built in.

The switching spool 34 is provided with a notch 33 for connecting the pressure oil supply passage 32 to the intermediate chamber 36 as the switching spool 34 moves. The switching spool 34 is provided with the switching spool 34.
Notches 45, 45 'and 46, 46' are provided for connecting the cylinder port 38a or 38b to the passage 40 or the auxiliary port 44 as the cylinder moves.

The auxiliary ports 44, 44 are provided between the cylinder ports 38a, 38b and the tank line 47, and are provided between the auxiliary ports 44, 44 and the tank line 47 from the cylinder ports 38a, 38b. A flow rate adjusting means 48 for adjusting the opening degree A of the passage to the line 47 is provided.

The flow rate adjusting means 48 has a spool 50 and a spring 52, and the spool 50 has spool holes 53, 54, 5 and 5 formed in the valve body 30.
5 are slidably and liquid-tightly held at one end, and one end thereof is surrounded and held by a cover 56. One end of an internal passage 58 provided in the spool 50 is connected to a back chamber 6 formed in the cover 56 via a check valve 60 and a passage 61.
2, and the other end is open to the front chamber 64. In this case, the check valve 60 is moved from the back chamber 62 to the front chamber 6.
4 to prevent the flow of pressurized oil.

On the other hand, the front chamber 64 is connected to the intermediate chamber 36 through a passage 65 and accommodates the spring 52 in the front chamber 64 so that the other end of the spool 50 is elastically connected. keeping.

Thus, the flow rate adjusting means 48
As the spool 50 moves downward against the resilience of the spring 51, the opening A thereof is regulated by the notch 50b while the shoulder 50a of the spool 50 is engaged with the spool hole 54, and becomes gradually smaller. It is configured to be.

Further, an auxiliary port 4 connected to one of the cylinder ports 38a is connected to the switching spool 34.
4 and a passage 40, a check valve 72 is provided to connect the auxiliary port 44 and the passage 40 to each other, and a part of the return oil from the one cylinder port 38a is transferred to the other cylinder port 38a. 38b.

In the configuration shown in FIG. 1 of this embodiment, the switching spool is provided with a center bypass passage 66 to constitute an open center type hydraulic control device. Of course, it can be configured as a control device.

Further, in this embodiment, a plurality of switching valves having the structure shown in FIG. 1 are included, and each back chamber (for example, 62 ') in the flow rate adjusting means (not shown) of another switching valve is included. The connection is made through the communication passage 68,
Is connected to the tank T via a throttle 70 as appropriate.

Next, the operation of the hydraulic control apparatus having the above-described configuration and having a regeneration function in the present embodiment will be described with reference to a hydraulic circuit diagram shown in FIG.

In the hydraulic circuit shown in FIG. 2, a plurality of switching valves (two in the illustrated example) having the configuration shown in FIG. 1 are provided, and these switching valves 80 and 81 are connected to the cylinder ports 38a and 38b, respectively. On the other hand, the actuator 82,
83 are connected. And each of the switching valves 8
The structures of 0 and 81 have the structure shown in FIG. 1 described above. Therefore, the same reference numerals are given to the same components of only one of the switching valves 80 and will be described.

(1) Independent operation In a hydraulic control apparatus having a configuration shown in FIG. 1 or a plurality of switching spools having the same configuration, when the switching spool of one switching valve 80 shown in FIG. 2 is operated, That is, in FIG. 1, when the switching spool 34 is moved rightward, the notch 33 provided in a part of the switching spool 34 is provided.
Opens into a common pressure oil supply passage 32, from which the pressure oil flows into the intermediate chamber 36, this pressure oil opens the check valve 42, and the notch 4 provided in the passage 40 and the switching spool 34
After passing through 5 ', it reaches one cylinder port 38b and is supplied to the actuator 82.

On the other hand, the return oil from the actuator 82 flows in from the other cylinder port 38a, reaches the auxiliary port 44 through the notch 46 provided in the switching spool 34, and returns to the recess 51 of the spool 50 of the flow rate adjusting means 48. Via an annular passage 54a formed by a spool hole 54 provided in the valve body 30, the tank line 47 is reached,
It is discharged to the tank T.

Therefore, in the case of single operation, the flow rate adjusting means 4
8, the pressure oil in the intermediate chamber 36 passes through the passage 65 and the front chamber 6.
4. Internal passage 58 of spool 50, check valve 60, passage 6
1 to the back room 62. Further, the pressure oil passes through the communication passage 68, and the back chamber (62 ') related to the other switching valve 81.
And a part thereof is discharged to the tank T through a relatively small throttle 70, so that the pressure in the back chamber 62 becomes substantially the same as the pressure in the front chamber 64. Moreover, in this case, since the spool 50 holds the opening A of the annular passage 54a at the open position by the spring force of the spring 52 provided in the front chamber 64, the return oil from the cylinder port 38a is subjected to flow rate adjustment. Without any restrictions by means 48, the tank T
Can be discharged to

(2) A plurality of switching spools are operated simultaneously.
Case (Operation on High Load Side) The spool 50 related to the high load side is the same as the case of the single operation.

(3) A plurality of switching spools are operated simultaneously.
Case (Operation on Light Load Side) Assuming that the switching valve shown in FIG. 1 is on the light load side, when the switching spool 34 is operated to the right similarly to the case of the single operation,
The direction of the flow of pressurized oil is the same as in (1) above,
In the flow rate adjusting means 48, with respect to the back chamber 62,
As in the case of (1), the pressure of the intermediate chamber (36) on the high load side flows in through the communication passage 68, and the pressure oil is supplied to the check valve provided inside the spool 50 on the light load side. Valve 60
Accordingly, the pressure in the back chamber 62 on the light load side becomes higher than the pressure in the front chamber 64 on the light load side because the flow to the front chamber 64 on the light load side is blocked. Therefore, when the force due to the pressure difference of the back chamber 62 with respect to the front chamber 64 overcomes the spring force of the spring 52, the spool 50 of the flow rate adjusting means 48 is moved downward and communicates from the auxiliary port 44 to the tank line 47. The opening degree A of the passage is restricted, and the cylinder port 38a
Gives resistance to return oil from.

In this state, if the load 82 ′ for driving the actuator 82 connected to the switching valve 80 is a load that falls under its own weight, meter-out control is performed, and the load is set by the spool 50 of the flow rate adjusting means 48. Depending on the opening degree, the pressure in one oil chamber 82b of the actuator 82 becomes higher than the pressure in the other oil chamber 82a, so that a part of the return oil flowing from the cylinder port 38a to the auxiliary port 44 is Through the passage 40 to the cylinder port 38b.

Therefore, the actuator 82 is driven at a sufficient speed even if the return oil passage is restricted by the flow rate adjusting means 48, and the oil supplied from the variable displacement pump is supplied to another high load side switching valve. Since it is positively supplied to 81, a predetermined drive speed can be obtained for each actuator even when a plurality of switching valves are simultaneously operated.

Further, according to the hydraulic control apparatus of the present invention having the above-described structure, if the corresponding switching valve is in the neutral state in the passage for regenerating the return oil from the auxiliary port 44, the pressure by the variable displacement pump acts. Since it is a part that does not perform the pressure cycle, it is not subjected to a high-frequency pressure cycle as seen in the related art, and the safety is extremely excellent.

Embodiment 2 FIG. 3 shows another embodiment of the hydraulic control apparatus having a regeneration function according to the present invention, and shows a modification of the hydraulic circuit of Embodiment 1 shown in FIG. is there.

That is, in FIG. 3, the basic structure of the hydraulic control apparatus of the present embodiment is the same as that of the embodiment shown in FIG. 2, and a pilot pump P 'is provided. Is connected to the communication passage 68 via the throttle 85 and the check valve 84. Reference numeral 86 indicates a relief valve. That is, in the present embodiment, when the pressure selected by the flow rate adjusting means 48 of each of the switching valves 80 and 81 is lower than the supply pressure from the pilot pump P ', the flow rate adjusting means 48 For example, in the configuration of the switching valve shown in FIG. 1, a pressure is applied to the back chamber 62 so as to adjust in the closing direction. The other configuration is the same as the configuration of the hydraulic circuit shown in FIG. 2, and the same components are denoted by the same reference numerals and detailed description thereof will not be repeated.

In the switching spools 34 of the switching valves 80 and 81, when supplying and discharging the pressure oil to and from the cylinder ports 38a and 38b through the cutouts 45 and 45 'formed in the switching spool 34, Notch 45, 45 '
Is set to a size corresponding to the supply amount of the pressure oil from the variable displacement pump P driven at a predetermined rotation speed (in the case of a hydraulic shovel, for example, 2000 rpm).

However, depending on the working conditions of the actuators 82 and 83, the amount of oil supplied from the variable displacement pump P may be small. In this case, for example, when the engine speed for noise prevention is used at 700 rpm,
With the opening degree of the notches 45, 45 'set under the above conditions,
For example, when operating the load that falls under its own weight, if the switching spool 34 is moved to the right in FIG. 1, the opening degree of the cutouts 45 and 45 'increases, and the load tends to fall under its own weight. In this case, since the amount of oil supplied from the variable displacement pump P is small, the amount of pressure oil supplied to the cylinder port 38b is insufficient, and there is a concern that the operation of the actuators 82 and 83 becomes difficult.

However, as shown in FIG. 3, by applying a predetermined pilot pressure to the communication passage 68, ie, the back chamber 62 in FIG.
When the amount of oil supplied from the pump is insufficient and the pressure in the intermediate chamber 36 is reduced, the force caused by the pressure difference from the pilot pressure acting on the back chamber 62 causes the spool 50 of the flow rate adjusting means 48 to By moving the auxiliary port 44 in the closing direction against the force, the amount of return oil from the auxiliary port 44 to the tank line 47 is limited, and the pressure of the auxiliary port 44 becomes higher than the pressure of the passage 40, and the check valve The opening 72 opens to supply a portion of the return oil from the auxiliary port 44 to the passage 40, and this return oil is supplied to the cylinder port 38b, which can prevent cavitation of the actuator 80 and prevent a reduction in speed. be able to.

Further, in this embodiment, the pilot pressure is determined by the balance with the pressure of the front chamber 64 in FIG.
The counter 50 has a counterbalance function for operating the spool 50 and adjusting the opening of the passage communicating from the auxiliary port 44 to the tank line 47. This pressure may be set by the relief valve 72 in FIG. From the pressure oil supply passage 32 through a pressure reducing valve (not shown).

Embodiment 3 FIG. 4 shows still another embodiment of the hydraulic control apparatus having a regeneration function according to the present invention, and shows a modification of the hydraulic circuit of Embodiment 2 shown in FIG. It is.

That is, in this embodiment, when the pilot pressure is supplied from the outside using the pilot pump P 'in the hydraulic control apparatus of the second embodiment shown in FIG. 3, a switching valve for applying the pilot pressure is provided. It is possible to specify. In this case, for example, as shown in FIG. 4, by providing a check valve 88 in a part of the communication passage 68, the above-described counter balance function can be added only to the switching valve 80 to which the actuator 82 is connected. . The other configuration is the same as the configuration of the hydraulic circuit shown in FIGS. 2 and 3, and the same components are denoted by the same reference characters and detailed description thereof will not be repeated.

As described above, the hydraulic control apparatus having a regeneration function when applied to a hydraulic excavator has been described as a preferred embodiment of the present invention. However, the present invention is not limited to the above-described embodiment, and the spirit of the present invention is not limited thereto. Many design changes are possible without departing from the scope.

[0049]

As described above, the hydraulic control apparatus having the regeneration function according to the present invention comprises connecting a control valve having a plurality of switching valves to a hydraulic pump, and connecting an actuator to each of the switching valves. In the hydraulic control device configured to supply and discharge the pressure oil from the hydraulic pump to each actuator by operating each of the switching valves, each of the switching valves is slidably and liquid-tight within a valve body. A switching spool that is supported, a plurality of oil passages that are communicated or blocked according to the position of the switching spool of the switching valve, a pressure oil supply passage that supplies pressure oil from the hydraulic pump to the oil passage, A notch provided in the switching spool according to the movement of the switching spool between the cylinder port communicating with the oil supply passage and the cylinder port and the pressure oil supply passage is used to supply the pressure oil. An intermediate chamber that opens into a passage and is supplied with pressurized oil from the pressurized oil supply passage via the notch, a tank line that communicates with the intermediate chamber, and an auxiliary provided between the tank line and the cylinder port. When the switching valve is operated, pressure oil is supplied from the pressure oil supply passage to the actuator via the intermediate chamber and one cylinder port, and the other cylinder port and the auxiliary port are supplied from the actuator to the other cylinder port and the auxiliary port. To return to the tank line through to discharge the oil, further provided flow rate adjusting means on the oil path from the auxiliary port to the tank line,
The oil passage between the auxiliary port and the tank line is configured to be adjusted in the opening direction by the pressure of the intermediate chamber in the flow rate adjusting means and to be adjusted in the closing direction by the external signal pressure, and the auxiliary port And, in the oil passage from the intermediate chamber to the cylinder port, the check valve is connected and arranged in a direction for preventing the flow from the oil passage to the auxiliary port, so that the check valve is connected to the common pressure oil supply passage. When a plurality of switching valves are simultaneously operated, pressure oil can be supplied simultaneously to actuators having different load pressures connected to the respective switching valves and in accordance with the operation amounts of the respective switching valves, and at the same time, own weight can be reduced. Cavitation can be reliably prevented even when manipulating a descending load. Not only that, but also with the addition of a counter balance function, it is possible to improve operability and safety and prevent reduction in speed, regardless of the amount of oil supplied by the variable displacement pump, thereby improving productivity. Advantages, such as being possible, are obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a main part showing a schematic configuration as an embodiment of a hydraulic control device having a regeneration function according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic control system of the hydraulic control device shown in FIG.

FIG. 3 is a hydraulic circuit diagram showing another embodiment of the hydraulic control device having a regeneration function according to the present invention.

FIG. 4 is a hydraulic circuit diagram showing still another embodiment of the hydraulic control device having the regeneration function according to the present invention.

FIG. 5 is an explanatory sectional view of a main part showing a schematic configuration of a conventional hydraulic control device having a regeneration function.

6 is a hydraulic circuit diagram showing a hydraulic control system of the hydraulic control device shown in FIG.

FIG. 7 is a hydraulic circuit diagram showing a modified example of the hydraulic control circuit shown in FIG.

[Explanation of symbols]

 Reference Signs List 30 valve body 32 pressure oil supply passage 33 notch 34 switching spool 36 intermediate chamber 38a, 38b cylinder port 40 passage 42 check valve 44 auxiliary port 45, 46, 45 ', 46' notch 47 tank line 48 flow rate adjusting means 50 Spool 50a Shoulder 50b Notch 51 Recess 52 Spring 53, 54, 55 Spool hole 54a Annular passage 56 Cover 58 Internal passage 60 Check valve 61 Passage 62 Backroom 62 'Other backroom 64 Front chamber 65 Passage 66 Center bypass Passage 68 Communication passage 70 Restrictor 72 Check valve 80, 81 Switching valve 82, 83 Actuator 82a, 82b Oil chamber 84 Check valve 85 Restrictor 86 Relief valve 88 Check valve P Variable displacement pump P 'Pilot pump T tank

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[Procedure amendment]

[Submission date] February 3, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

The inventor of the present invention has made intensive studies and studies and, as a result, has connected a control valve having a plurality of switching valves to the hydraulic pump, and connected an actuator to each of the switching valves, thereby obtaining the switching valves. , A hydraulic control device is configured to supply and discharge hydraulic oil from the hydraulic pump to each actuator, and each of the switching valves is slidably supported in a valve body in a liquid-tight and slidable manner. When,
A plurality of oil passages to be communicated or blocked according to the position of the switching spool of the switching valve, and a pressure oil supply passage for supplying pressurized oil from the oil passage is the hydraulic pump, the cylinder port
And a notch provided in the switching spool between the cylinder port and the pressure oil supply passage in accordance with the movement of the switching spool. The notch opens in the pressure oil supply passage and the pressure oil supply passage extends through the notch. An intermediate chamber to which pressurized oil is supplied from
A tank line and an auxiliary port provided between the tank line and the cylinder port, and when the switching valve is operated, the pressure oil is supplied from the pressure oil supply passage to the actuator through the intermediate chamber and one of the cylinder ports. The pressure oil is supplied, the actuator returns to the tank line via the other cylinder port and the auxiliary port, and the oil is discharged.Furthermore, a flow rate adjusting means is provided on an oil passage from the auxiliary port to the tank line, The oil passage between the auxiliary port and the tank line is adjusted in the opening direction by the pressure of the intermediate chamber in the flow rate adjusting means, and is adjusted in the closing direction by the external signal pressure. Check that the flow from the oil passage to the auxiliary port is blocked in the oil passage from the chamber to the cylinder port. Is connected and arranged, it is possible to simultaneously supply pressure oil to each actuator connected to each switching valve having a different load pressure and in accordance with the operation amount of each switching valve, Even when operating a load, the occurrence of cavitation can be reliably prevented, a predetermined speed can be maintained for each actuator, and a counterbalance function can be added. Regardless, it has been found that improvement of operability and safety and prevention of speed price list can be achieved, and improvement of productivity can be achieved.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

[0016]

In order to achieve the above object, a hydraulic control device having a regeneration function according to the present invention comprises connecting a control valve having a plurality of switching valves to a hydraulic pump, and connecting each of the switching valves to the hydraulic pump. In a hydraulic control device configured to supply and discharge pressure oil from the hydraulic pump to each actuator by connecting an actuator and operating each of the switching valves, each of the switching valves is liquid-tight within a valve body. a switching spool which is slidably supported to and to have a plurality of oil passages to be communicated or blocked according to the position of the switching spool of the switching valve, pressure the oil passage for supplying pressurized oil from the hydraulic pump and an oil supply passage, the cylinder port and the cutouts is the pressure oil supply passage provided in the switching spool according to the movement of the switching spool between said cylinder port and said pressurized oil supply passage An intermediate chamber which pressure oil is supplied from the pressurized oil supply passage through an open the cut portion, Tankurai
And an auxiliary port provided between the tank line and the cylinder port. When the switching valve is operated, the hydraulic oil is supplied from the pressure oil supply passage to the intermediate chamber and to the actuator through one of the cylinder ports. It is configured to supply pressure oil, return to the tank line from the actuator via the other cylinder port and the auxiliary port, and discharge the oil, and further provide a flow rate adjusting means on an oil passage from the auxiliary port to the tank line. The oil passage between the auxiliary port and the tank line is adjusted in the opening direction by the pressure of the intermediate chamber in the flow rate adjusting means, and is adjusted in the closing direction by the external signal pressure; A check valve is connected to the oil passage from the port and the intermediate chamber to the cylinder port in a direction to prevent the flow from the oil passage to the auxiliary port. Characterized in that the placed.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction contents]

[0049]

As described above, the hydraulic control apparatus having the regeneration function according to the present invention comprises connecting a control valve having a plurality of switching valves to a hydraulic pump, and connecting an actuator to each of the switching valves. In the hydraulic control device configured to supply and discharge the pressure oil from the hydraulic pump to each actuator by operating each of the switching valves, each of the switching valves is slidably and liquid-tight within a valve body. A switching spool that is supported, and a plurality of oil passages that are communicated or blocked according to the position of the switching spool of the switching valve;
A hydraulic oil supply passage for supplying hydraulic oil from the hydraulic pump, a cylinder port, and a notch provided in the switching spool between the cylinder port and the hydraulic oil supply passage according to movement of the switching spool. An intermediate chamber that opens into the pressure oil supply passage and is supplied with pressure oil from the pressure oil supply passage through the notch, a tank line, and an auxiliary port provided between the tank line and the cylinder port. When the switching valve is operated, pressure oil is supplied from the pressure oil supply passage to the actuator through the intermediate chamber and one cylinder port, and from this actuator through the other cylinder port and the auxiliary port. The system is configured to return oil to the tank line and discharge oil, and further, a flow rate adjusting means is provided on an oil passage from the auxiliary port to the tank line. The oil passage between the oil tank and the tank line is adjusted in the opening direction by the pressure of the intermediate chamber in the flow rate adjusting means, and is adjusted in the closing direction by the external signal pressure. In the oil passage from the chamber to the cylinder port, the check valve is connected and arranged in such a direction as to block the flow from the oil passage to the auxiliary port. When the switching valves are operated at the same time, pressure oil can be supplied to each actuator connected to each switching valve having a different load pressure at the same time and in accordance with the operation amount of each switching valve, and the load that falls by its own weight can be supplied. When operating the actuator, it is possible to reliably prevent cavitation and to maintain a predetermined speed for each actuator. In addition, a counterbalance function has been added to improve operability and safety and prevent reduction in speed, regardless of the amount of oil supplied by the variable displacement pump, thereby improving productivity. Benefits are obtained.

[Procedure amendment]

[Submission date] April 12, 1999

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

Claims (4)

[Claims] 1. A control valve having a plurality of switching valves built therein is connected to a hydraulic pump, an actuator is connected to each of the switching valves, and each of the switching valves is operated. In the hydraulic control device configured to supply and discharge to and from the actuator, each of the switching valves communicates or shuts off according to a position of a switching spool supported in a valve body in a liquid-tight and slidable manner, and a switching spool of the switching valve. A plurality of oil passages, a pressure oil supply passage for supplying pressure oil from the hydraulic pump to the oil passage, a cylinder port communicating with the pressure oil supply passage, the cylinder port and the pressure oil supply. A notch provided in the switching spool opens to the pressure oil supply passage in accordance with the movement of the switching spool between the passage and the passage, and pressure oil is supplied from the pressure oil supply passage through the notch. An intermediate chamber, a tank line communicating with the intermediate chamber, and an auxiliary port provided between the tank line and the cylinder port. When the switching valve is operated, the pressure oil supply passage From the intermediate chamber and one of the cylinder ports to supply the pressure oil to the actuator, from the actuator to the other cylinder port and the auxiliary port to return to the tank line to discharge the oil, further from the auxiliary port A flow rate adjusting means is provided on an oil path leading to the tank line, and an oil path between the auxiliary port and the tank line is adjusted in the opening direction by the pressure of the intermediate chamber in the flow rate adjusting means and closed by an external signal pressure. In the direction from the auxiliary port and the intermediate chamber to the cylinder port. Hydraulic control device having a playback function, characterized in that the check valve in the direction for blocking the flow to the auxiliary port connections are arranged. 2. The external signal pressure for adjusting the flow control means in the closing direction comprises the pressure of the intermediate chamber of another switching valve.
A hydraulic control device having the regeneration function described in the above. 3. The pressure in the intermediate chamber of each switching valve is detected, the maximum pressure among these pressures is selected, and oil corresponding to the external signal pressure is supplied to flow rate adjusting means of the switching valve in accordance with the maximum pressure. 2. The hydraulic control device having a regeneration function according to claim 1, wherein the hydraulic control device is configured to apply pressure. 4. The regeneration function according to claim 1, wherein another pilot signal pressure is supplied via a check valve to a supply line of the external signal pressure acting on the flow rate adjusting means of each switching valve. Hydraulic control device having: