KR20170038160A - Direction converter valve and hydraulic system - Google Patents

Abstract

The present invention relates to a directional selecting valve in which a regeneration mechanism and a discharge mechanism of working oil are integrally configured, and a hydraulic system using such a directional selecting valve. A disposition position of a valve slider (32) in a valve hole (31) is determined in accordance with pressure of working oil supplied from a supply path (20) to the valve hole (31) and pressure of working oil supplied from a discharge path (22) to the valve hole (31), to regulate the flow path in the valve slider (32). When the pressure of the working oil supplied from the discharge path (22) to the valve hole (31) is higher than the pressure of the working oil supplied from the supply path (20) to the valve hole (31), the valve slider (32) regulates a first connection flow path (33) connecting the discharge path (22) to the supply path (20), into the valve hole (31). When the pressure of the working oil supplied from the discharge path (22) to the valve hole (31) is lower than the pressure of the working oil supplied from the supply path (20) to the valve hole (31), the valve slider (32) regulates a second connection flow path connecting the discharge path (22) to a second tank (15), into the valve hole (31).

Description

DIRECTION CONVERTER VALVE AND HYDRAULIC SYSTEM [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direction switching valve capable of switching a flow path, and a hydraulic system using such a direction switching valve.

BACKGROUND ART [0002] In the field of construction machinery and the like, a hydraulic system for switching a flow path connected to a pump device, an actuator, and a discharge tank by a direction switching valve is used in accordance with an operation of an actuator.

For example, Patent Document 1 discloses a hydraulic system in which, according to the operation of a boom cylinder, a flow path connected to a main pump, a boom cylinder, and a tank is switched by an operation valve. In the hydraulic system of Patent Document 1, the return oil from the piston chamber of the boom cylinder at the time of descent is guided to the hydraulic motor as the regenerated flow rate by the valve mechanism, and if necessary, .

Japanese Patent Application Laid-Open No. 11-179541

In the hydraulic system described above, the actuator has a supply side portion and an exhaust side portion, and during normal operation, the hydraulic oil is supplied from the pump device to the supply side portion, and the hydraulic oil is discharged from the discharge side portion. In addition, there is a case where the hydraulic system of Patent Document 1 and the regenerating mechanism for returning the operating oil (return oil) discharged from the discharge side portion to the supply side portion and providing it to the normal driving are constituted. This regeneration mechanism is very useful from the viewpoint of effective utilization of energy, and can be relatively easily implemented using a check valve or the like, so that it can be suitably employed also in a hydraulic system such as an excavator.

An actuator such as an arm, a boom and a bucket of an excavator is driven not only in the air but also directly or indirectly grounded to an object. Excavation force is not required when the actuator is driven in the air, but excavating force is required when the actuator is driven with the object grounded. When the excavating force is required in this way, the above-mentioned " regenerating mechanism for returning the return oil to the supplying-side portion " alone is insufficient and actuation of the hydraulic oil from the discharge- desirable.

Although it is possible to provide such a discharge mechanism of the operating oil separately from the above-described regenerating mechanism, the configuration in which the discharging mechanism and the regenerating mechanism are separately provided has a tendency that the space efficiency becomes poor and the piping configuration becomes complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a direction switching valve in which a regeneration mechanism and a discharge mechanism of a hydraulic fluid are integrally formed, and a hydraulic system using such a direction switching valve.

According to an aspect of the present invention, there is provided a valve control apparatus comprising: a valve hole formed in a valve body; a supply passage connected to the valve hole, the actuator and the pump device and supplied with operating fluid from the pump device; A discharge port provided in the valve hole, and a discharge port provided in the valve hole so as to be movable in the valve hole according to the pressure of the operating oil supplied from the supply passage to the valve hole and the operating oil supplied from the discharge passage to the valve hole, When the pressure of the operating oil supplied from the discharge passage to the valve hole is larger than the pressure of the operating oil supplied from the supply passage to the valve hole, the first connection passage for communicating the discharge passage with the supply passage is provided in the valve hole A valve slider disposed at a prescribed position, and a second connection for communicating the discharge passage with the discharge tank It relates to a directional control valve having parts form a flow path capable of forming a.

According to this aspect, the first connection flow passage is defined in accordance with the magnitude relationship between the " pressure of the hydraulic oil supplied from the discharge passage to the valve hole " and " pressure of the hydraulic oil supplied from the supply passage to the valve hole & The second connection flow path is defined. Therefore, the first connecting flow path usable as the operating fluid regeneration mechanism and the second connecting flow path usable as the operating fluid discharging mechanism can be integrally formed by the direction switching valve.

The valve slider includes a first hydraulic oil acting portion that is movable in the first direction and the second direction in the valve hole and in which a force in the first direction acts by the hydraulic oil supplied from the discharge passage to the valve hole, And a second operating oil operating portion to which a force in the second direction is applied by the operating oil supplied to the hole.

According to this aspect, depending on the " force of the operating oil supplied from the discharge passage to the valve hole " acting on the first operating oil operating portion and the " force of operating oil supplied from the supplying passage to the valve opening & , The valve slider can be moved.

When the pressure of the hydraulic oil supplied from the discharge passage to the valve hole is larger than the pressure of the hydraulic oil supplied from the supply passage to the valve hole, the valve slider has a discharge- The communication between the discharge passage and the cutout for connection to the discharge tank may be restricted rather than when the pressure of the operating oil supplied from the discharge passage to the valve hole is smaller than the pressure of the operating oil supplied from the supply passage to the valve hole.

According to this aspect, the state of communication between the discharge passage and the cutout for connection to the discharge tank is determined according to the " force of the working oil supplied from the discharge passage to the valve hole " and " the force of the working oil supplied from the supply passage to the valve hole & The effectiveness of the discharge mechanism of the operating oil is appropriately switched. In the case of " limiting the communication between the discharge passage and the cutout for connection to the discharge tank ", it is necessary to completely block the gap between the discharge passage and the discharge tank connection to completely communicate (Reduced) of the opening area through which the operating oil can flow "between the discharge passage and the cutout for connection to the discharge tank, as well as the communication between the discharge passage and the cutout for connection to the discharge tank And the like.

The valve body is provided with a first connection hole communicating with the valve hole, a second connection hole and a third connection hole. The first connection hole is connected to the exhaust passage, and hydraulic oil is supplied from the exhaust passage to the first hydraulic oil- The second connection hole is connected to the discharge passage and the third connection hole is communicated with the discharge tank, and the valve slider is configured such that the pressure of the operating oil supplied from the discharge passage to the valve hole is supplied from the supply passage to the valve hole And the pressure of the operating oil supplied from the discharge passage to the valve hole is greater than the pressure of the operating oil supplied from the supply passage to the valve hole When the pressure is larger than the pressure, the pressure of the hydraulic oil supplied from the discharge passage to the valve hole is smaller than the pressure of the hydraulic oil supplied from the supply passage to the valve hole, It may restrict the communication between the hole and the discharge tank section for connection associated.

According to this aspect, the first connection hole, the second connection hole, and the third connection hole can appropriately guide the operating oil from the discharge passage to the first operating oil operating portion, can do.

When the pressure of the operating oil supplied from the discharge passage to the valve hole is smaller than the pressure of the operating oil supplied from the supply passage to the valve hole, the valve slider is provided on the valve seat provided on the valve body forming the boundary between the supply passage and the valve hole It may be moved to the first position in which it is brought into close contact and moved to the second position spaced from the valve seat when the pressure of the hydraulic oil supplied from the discharge passage to the valve hole is larger than the pressure of the hydraulic oil supplied from the supply passage to the valve hole.

According to this aspect, the first connecting flow path can be appropriately defined in accordance with the movement of the valve slider.

According to another aspect of the present invention, there is provided an air conditioner comprising: the directional control valve; a pump device connected to the supply passage of the directional control valve; an actuator connected to the supply passage and the discharge passage of the directional control valve; And a discharge tank communicating with the discharge tank. And a discharge tank communicating with the second connection passage of the directional control valve.

According to the present invention, the first connection flow passage is defined in accordance with the magnitude relationship between the "pressure of the hydraulic oil supplied from the discharge passage to the valve hole" and the "pressure of the hydraulic oil supplied from the supply passage to the valve hole" The second connection flow path is defined. Therefore, the first connecting flow path usable as the operating fluid regeneration mechanism and the second connecting flow path usable as the operating fluid discharging mechanism can be integrally formed by the direction switching valve.

1 is a circuit diagram for explaining a functional configuration of a hydraulic system;
Fig. 2 is a view showing an example of a valve configuration (refer to the symbol " A " in Fig. 1) of the directional control valve in the first drive state;
3 is a circuit diagram schematically showing an example of a direction switching valve for realizing the first driving state and showing a state in which the valve slider is disposed at the regeneration driving position.
Fig. 4 is a circuit diagram schematically showing an example of a direction switching valve for realizing the first driving state, and showing a state in which the valve slider is disposed at the discharge driving position. Fig.
5 is a circuit diagram for explaining a functional configuration of a hydraulic system;
6 is a view showing an example of the valve configuration (refer to reference character " C " in Fig. 5) of the directional control valve shown in Fig. 5;
7 is a cross-sectional view of a direction switching valve disposed at a neutral position;
8 is a side view showing an exploded state of the spool;
9 is a sectional view of a direction switching valve disposed at a first operating position, showing a state in which a space between a second actuator passage and a third supply passage (second bridge passage) is blocked;
10 is a cross-sectional view of a part of a direction switching valve disposed at a first operating position, showing a state in which a second actuator passage and a third supply passage (second bridge passage) are in communication with each other.
11 is a sectional view of a direction switching valve disposed in a second operating position;

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, the basic concept of the present invention will be described.

Fig. 1 is a circuit diagram for explaining the functional configuration of the hydraulic system 10. Fig. In the hydraulic system 10 of the present embodiment, the variable displacement pump device 11 is connected to the actuator 12 via the direction switching valve 13, and the hydraulic oil 10 between the pump device 11 and the actuator 12 Is defined by the directional valve (13). The pump device 11 is connected to the direction switching valve 13 through the supply path 20 provided with the check valve 16 and the direction switching valve 13 is connected to the actuator 20 via the supply path 20, And is connected to the head chamber 12a of the head 12. The load chamber 12b of the actuator 12 is connected to the direction switching valve 13 through the discharge passage 22 and the direction switching valve 13 is connected to the second tank 15 via the tank flow path 23. [ Respectively. The unloading passage 21 branched from the supply passage 20 is connected to the direction switching valve 13 and the direction switching valve 13 is connected to the first tank 14 through the unloading passage 21. [

The directional control valve 13 of the present embodiment can employ a flow path configuration of a neutral state (neutral position), a first drive state (first operation position) and a second drive state (second operation position) The directional switching valve 13 has a valve structure in the order from the left to the first driving state, the neutral state and the second driving state.

Fig. 2 is a view showing an example of the valve configuration (see the symbol " A " in Fig. 1) of the directional valve 13 in the first drive state. The directional control valve 13 in the first drive state in the present example includes a valve structure indicated by reference numeral B in Fig. 2 and is connected to the discharge passage 22 from the actuator 12 (rod chamber 12b) And the pressure of the hydraulic fluid supplied from the pump device 11 to the supply passage 20, the flow path configuration of the valve is determined.

That is, when the "pressure of the hydraulic oil discharged from the actuator 12 to the discharge passage 22" is larger than the "pressure of the hydraulic oil supplied from the pump device 11 to the supply passage 20" And the operating oil is sent from the discharge passage 22 to the supply passage 20. In this case, That is, in the directional control valve 13, the "hydraulic oil flowing through the discharge passage 22" is connected to the supply passage 20 connected to the pump device 11 and the actuator 12 (head chamber 12a) (See Fig. 1) to the pump device 11 while preventing the backflow to the pump device 11 by the check valve 16 (see Fig. 1) through the supply passage 20 And is sent to the actuator 12 (head room 12a). In the example shown in Fig. 2, the "direction in which the working fluid from the discharge path 22 and the working fluid from the supply path 20" of the directional control valve 13 and the " (20), " the flow rate regulation of the operating oil and the pressure adjustment are performed.

On the other hand, when the "pressure of the hydraulic oil supplied from the pump device 11 to the supply path 20" is larger than the "pressure of the hydraulic oil discharged from the actuator 12 to the discharge passage 22" And the working oil is sent from the discharge passage 22 to the tank flow passage 23. The valve opening of the tank passage 23 is connected to the discharge passage 22, In accordance with the magnitude relationship between the "pressure of the hydraulic oil supplied from the pump device 11 to the supply path 20" and the "pressure of the hydraulic oil discharged from the actuator 12 to the discharge passage 22" (That is, to be discharged) to the second tank 15 through the tank flow passage 23 is determined to be the operating fluid discharged from the discharge passage 22 to the discharge passage 22 do. 1, the first tank 14 and the second tank 15 are shown as separate tanks, but the first tank 14 and the second tank 15 may be the same tank.

When the directional control valve 13 is placed in the first drive state, the unloading passage 21 is shut off and the hydraulic fluid supplied from the pump device 11 is supplied to the supply passage 20 and the directional control valve 13 And is supplied to the actuator 12 (head room 12a).

On the other hand, when the directional control valve 13 is placed in the neutral state, as shown in Fig. 1, the supply passage 20 is shut off and the discharge passage 22 and the tank passage 23 are also shut off, The operating fluid supplied from the pump device 11 is sent to the first tank 14 through the unloading passage 21. [

1, the supply passage 20 to which the operating oil is supplied from the pump device 11 is connected to the discharge passage 13 through the direction switching valve 13, And the supply passage 20 connected to the actuator 12 is connected to the tank flow passage 23 through the direction switching valve 13. [ Therefore, when the direction switching valve 13 is in the second driving state, the actuator 12 is driven to perform an operation opposite to that in the case where the direction switching valve 13 is in the first driving state. 1, the operating fluid is supplied to the head chamber 12a and the operating fluid is discharged from the load chamber 12b. In the case of the second driving state, however, the load chamber 12b, And the operating oil is discharged from the head chamber 12a.

Next, a specific example of the " valve configuration of the directional valve 13 in the first driven state " shown in Fig. 2 will be described.

3 and 4 are circuit diagrams schematically showing one example of the directional control valve 13 for realizing the first drive state and the state in which the valve slider 32 is arranged at the regeneration drive position is shown in Fig. , And the state in which the valve slider 32 is disposed in the discharge driving position is shown in Fig. 3 and 4 schematically show that the supply path 20 drawn by the line from the pump device 11 is connected to the supply path 20 having a predetermined diameter in practice, (20) extends from the pump device (11) toward the valve hole (31) unilaterally without being interrupted.

In the hydraulic system 10 of the present embodiment, the supply path 20 is connected to the pump device 11, the actuator 12 (the head chamber 12a) and the valve hole 31 of the directional control valve 13 , And the operating oil is supplied from the pump device (11). On the other hand, the discharge passage 22 is connected to the actuator 12 (the rod chamber 12b) and is connected to the valve hole 31 of the direction switching valve 13, (31). In this example, the discharge passage 22 extending from the actuator 12 (rod chamber 12b) branches off in the middle, and one of the branched discharge passages 22 is formed in the valve body 30 And the other branched discharge passage 22 connected to the connection hole 38 is connected to the second connection hole 39 formed in the valve body 30.

The directional control valve 13 has a valve hole 31 formed in the valve element 30 and a valve hole 31 formed in the valve hole 31 in a first direction And a valve slider 32 movably installed at a position indicated by reference sign " D2 "

The valve slider 32 is provided in the valve hole 31 in accordance with the pressure of the operating oil supplied from the supply passage 20 to the valve hole 31 and the pressure of the operating oil supplied from the discharge passage 22 to the valve hole 31 And the flow path is defined in the valve hole 31 in accordance with the arrangement in the valve hole 31. [

The valve slider 32 of this embodiment has a first valve land portion 42a and a second valve land portion 42b sliding on the peripheral wall of the valve hole 31 and a first valve land portion 42a, The gap between the second valve land portion 42b and the second valve land portion 42b is greater than the first valve land portion 42b. And a through hole 43 passing through the valve slider 32 between the valve slider 32 and the valve slider 32. The first valve land portion 42a and the second valve land portion 42b of the first valve land portion 42a and the second valve land portion 42b are disposed in the vicinity of the connecting portion of the valve hole 31 and the supply passage 20 (The end surface constituted by the valve land portion 42a) has an inclined surface. The inclined surface of the inclined surface is inclined by a force in the first direction D1 by the operating oil supplied from the discharge passage 22 to the valve hole 31 The first operating oil working portion 35 is formed. On the other hand, the end surface of the valve slider 32 constituted by the second valve land portion 42b is pressed by the operating oil supplied from the supply passage 20 to the valve hole 31 in the second direction D2 A second operating oil operating portion 36 to which the force of the second operating oil acts. The discharge tank connection cutout portion 37 is formed by combining the discharge passage 22 and the second tank 30 in combination with the second connection hole 39, the third connection hole 40 and the tank passage 23, (Refer to FIG. 4) that communicates with the first connection channel 15.

The valve body 30 is formed with a first connection hole 38, a second connection hole 39 and a third connection hole 40 communicating with the valve hole 31. The first connection hole 38 is connected to the discharge passage 22 and guides the hydraulic oil from the discharge passage 22 to the first hydraulic oil acting portion 35 in the valve hole 31. The third connection hole (40) communicates with the second tank (15) through the tank flow path (23). The second connection hole 39 is connected to the discharge passage 22 and the valve slider 32 (particularly the first valve land portion 42a ) Or the like.

When the pressure of the operating oil supplied from the discharge passage 22 to the valve hole 31 is larger than the pressure of the operating oil supplied from the supply passage 20 to the valve hole 31 The pressure of the hydraulic oil discharged from the actuator 12 to the discharge passage 22 is larger than the pressure of the hydraulic oil supplied from the pump device 11 to the supply passage 20) (Second position) shown in Fig. The operating oil discharged from the actuator 12 to the discharge passage 22 flows into the valve hole 31 through the first connecting hole 38 and presses the first operating oil operating portion 35 to the valve slider 32 ) In the first direction D1, and the valve slider 32 is disposed at the regeneration drive position shown in Fig. The valve slider 32 is separated from the valve seat 41 which is provided in the valve body 30 and forms the boundary between the supply passage 20 and the valve hole 31, 38, the valve hole 31 (first connection passage 33), and the supply passage 20 are formed.

The valve slider 32 (particularly, the first valve land portion 42a) disposed at the regeneration drive position interrupts the gap between the second connection hole 39 and the cutout 37 for connection to the discharge tank, The connection hole 39 and the cutout 37 for connection to the discharge tank are in a non-combustion state. That is, when the pressure of the hydraulic oil supplied from the discharge passage 22 to the valve hole 31 is greater than the pressure of the hydraulic oil supplied from the supply passage 20 to the valve hole 31, When the pressure of the working oil supplied from the discharge passage 22 to the valve hole 31 is smaller than the pressure of the working oil supplied from the supply passage 20 to the valve hole 31, (Particularly, the communication between the second connection hole 39 and the cutout 37 for connection to the discharge tank) is restricted.

When the pressure of the operating oil supplied from the discharge passage 22 to the valve hole 31 is larger than the pressure of the operating oil supplied from the supply passage 20 to the valve hole 31, (Limiting) the communication between the discharge passage connecting portion 22 and the discharge tank connecting cutout portion 37 while the first connection hole 38 is closed and the discharge passage 22 is communicated with the supply passage 20 in combination with the first connection hole 38, And the flow path 33 is defined in the valve hole 31. In this manner, the actuator 12 is supplied with the operating fluid (not shown) from the actuator 12 through the discharge passage 22, the first connecting hole 38, the valve hole 31 (first connecting passage 33) And the hydraulic fluid discharged from the actuator 12 (rod chamber 12b) is returned to the actuator 12 (head chamber 12a) as return oil.

On the other hand, when the "pressure of the hydraulic oil supplied from the discharge passage 22 to the valve hole 31" is smaller than the "pressure of the hydraulic oil supplied from the supply passage 20 to the valve hole 31" The pressure of the hydraulic fluid discharged from the pump device 11 to the discharge passage 22 is smaller than the pressure of the hydraulic fluid supplied from the pump device 11 to the supply passage 20) (The first position). The operating fluid supplied from the supply passage 20 to the valve hole 31 presses the second operating oil acting portion 36 through the through hole 43 to move the valve slider 32 in the second direction D2, The valve slider 32 is disposed at the discharge driving position shown in Fig. The first hydraulic oil acting portion 35 of the valve slider 32 is brought into close contact with the valve seat 41 to cut off the communication between the valve hole 31 and the supply passage 20.

When the valve slider 32 is disposed at the discharge driving position, the discharge tank connection cutout portion 37 is connected to the second connection hole 39 and the third connection hole 40, and the second connection hole 39, The third connecting hole 40 guides the working oil from the discharge tank connecting cutout portion 37 to the tank flow path 23 from the discharge passage 22 to the discharge tank connecting cutout portion 37 .

When the pressure of the operating oil supplied from the discharge passage 22 to the valve hole 31 is smaller than the pressure of the operating oil supplied from the supply passage 20 to the valve hole 31, The second connection hole 39 and the tank passage 23 are connected to each other so that the discharge passage 22 and the second tank 15 are communicated with each other The second connecting passage 34 is defined in the valve hole 31 by the valve slider 32. [ As described above, in the present embodiment, the valve hole 31 and the valve slider 32 are used to form the second connection passage 34 for communicating the discharge passage 22 and the second tank 15 (discharge tank) Forming portion " In this way, the discharge passage 22, the second connection hole 39, the valve hole 31 (the discharge tank connection cutout portion 37 (second connection passage 34)), the third A flow path for sending hydraulic oil to the second tank 15 is formed through the connection hole 40 and the tank flow path 23 and the hydraulic fluid discharged from the actuator 12 is discharged to the second tank 15.

As described above, according to the directional control valve 13 of this embodiment, the "pressure of the operating oil supplied from the discharge passage 22 to the valve hole 31" and the "pressure of the operating oil supplied from the supply passage 20 to the valve hole 31" The first connection passage 33 (see FIG. 3) and the second connection passage 34 (see FIG. 4) can be defined in the valve hole 31 in accordance with the magnitude of the pressure. Therefore, the first connection passage 33, which can be used as the operating oil regeneration mechanism, and the second connection passage 34, which can be used as the operating oil discharge mechanism, can be integrally formed by the single directional control valve 13, The device configuration can be simplified.

Particularly, the operating fluid discharged from the actuator 12 using the first connection flow path 33 is regenerated in the actuator 12, thereby preventing the energy loss of the operating fluid, thereby improving the operating speed of the actuator 12. [ As described above, the operating oil used as the regeneration oil is supplied to the downstream side of the actuator 12, the discharge passage 22, the first connection hole 38, the first connection passage 33 and the check valve 16 Supply path 20 "), the working fluid can be reliably returned to the actuator 12 while ensuring sufficient regeneration amount of the working fluid. A flow path for discharging (unloading) the operating fluid discharged from the actuator 12 to the second tank 15 is formed in the second connection hole 39, the discharge tank connection cutout portion 37, the third connection hole 40 And the tank flow path 23, respectively. Therefore, during excavation, the excavating force required for excavation can be ensured by discharging the operating oil discharged from the actuator 12 through the oil line to the second tank 15.

The directional control valve 13, which can integrally constitute the "first connection passage 33", which can be used as a regeneration mechanism of the hydraulic oil, and the "second connection passage 34", which can be used as a hydraulic oil discharge mechanism, It is not limited to the example. For example, in the above-described embodiment, the example in which the pump device 11 has the "single hydraulic oil supply source" is described. However, even in the case where the pump device 11 has the "plural hydraulic oil supply sources" (13) can be applied.

Next, an example of a hydraulic system in which the pump device 11 has a plurality of supply sources of hydraulic oil will be described with reference to Figs. 5 to 11. Fig.

Fig. 5 is a circuit diagram for explaining a functional configuration of the hydraulic system 101. Fig. Fig. 6 is a diagram showing an example of the valve configuration (refer to symbol " C " in Fig. 5) of the directional control valve 13 shown in Fig. 6 is described in a manner based on JIS (Japanese Industrial Standards).

The hydraulic system (hydraulic circuit) 101 for a construction machine shown in Fig. 5 is a hydraulic system used in a construction machine (not shown). This construction machine is a machine for performing construction work. The construction machine is, for example, a hydraulic shovel. 5, the hydraulic system 101 for a construction machine includes a pump device 11, a tank 115, an actuator 120, and a direction switching valve 130. As shown in Fig.

The pump device 11 is a variable displacement hydraulic pump that discharges hydraulic oil. In the pump device 11, for example, the capacity is changed by changing the tilting angle of the swash plate, and when the capacity is changed, the discharge amount of the hydraulic oil per one rotation of the input shaft is changed. The pump device 11 is composed of two pumps. The pump device 11 includes a first pump 111 forming a first discharge port and a second pump 112 forming a second discharge port. The pump device 11 is, for example, a split pump. The split pump is a pump in which a plurality of pumps (the first pump 111 and the second pump 112) are driven by one input shaft. In the split pump, the first pump 111 and the second pump 112 are integrally formed. In the split pump, the discharge amount of the first pump 111 and the discharge amount of the second pump 112 are equal. Further, the pump device 11 may not be a split pump. The first pump 111 and the second pump 112 may be separate. The input shaft of the first pump 111 and the input shaft of the second pump 112 may be common or not common. The discharge amount of the first pump 111 and the discharge amount of the second pump 112 may be the same or different.

The tank 115 stores the operating oil. The tank 115 supplies operating oil to the pump device 11. [ In the tank 115, the hydraulic oil discharged from the pump device 11 and passed through the actuator 120 is returned. In the tank 115, the hydraulic oil discharged from the pump device 11 and not passing through the actuator 120 is returned.

The actuator 120 actuates the construction machine. The actuator 120 is a hydraulic actuator and is driven by supplying oil from the pump device 11. [ The actuator 120 is driven by supplying operating fluid from at least one of the first pump 111 and the second pump 112. [ The actuator 120 includes a hydraulic motor (not shown) and a hydraulic cylinder. When the construction machine is a hydraulic excavator, the use of the actuator 120 includes driving, turning, bucket rotation, arm loading, and boom loading. A concrete example of the actuator 120 is as follows. [Example 1] The actuator 120 is a hydraulic motor (traveling motor) for traveling a construction machine. The actuator 120 is a right traveling motor or a left traveling motor for driving a crawler (right or left crawler) of the lower traveling body of the construction machine. [Example 2] The actuator 120 is a hydraulic motor (orbiting motor) for turning the upper revolving structure relative to the lower traveling body. [Example 3] The actuator 120 is a hydraulic cylinder (bucket cylinder) for rotating the bucket with respect to the arm. EXAMPLE 4 The actuator 120 is a hydraulic cylinder (arm cylinder) for raising (lowering and rotating) an arm against a boom. [Example 5] The actuator 120 is a hydraulic cylinder (a cylinder for a boom) for relieving (raising and lowering) the boom against the upper revolving body. The actuator 120 may be other than those of the above-described [Example 1] to [Example 5], and may be, for example, a hydraulic cylinder for dozer operation. The actuator 120 includes a first hydraulic oil port 121 and a second hydraulic oil port 122.

The first hydraulic oil port 121 and the second hydraulic oil port 122 are the supply port and the discharge port for the hydraulic fluid to the actuator 120, respectively. The hydraulic oil is supplied to the first hydraulic oil port 121 and the hydraulic oil is discharged from the second hydraulic oil port 122 so that the actuator 120 operates as one side. Specifically, for example, the hydraulic cylinder is elongated or a hydraulic motor (not shown) is rotated to one side. The operating oil is supplied to the second operating oil port 122 and the operating oil is discharged from the first operating oil port 121 so that the actuator 120 operates on the other side (the side opposite to the "one side"). Specifically, for example, the hydraulic cylinder shrinks or the hydraulic motor rotates to the other side.

The directional control valve 130 is a valve for controlling the operation of the actuator 120. The directional control valve 130 is a valve for supplying and discharging hydraulic fluid to and from the actuator 120. The directional control valve 130 supplies the discharge hydraulic fluid of the pump device 11 to the actuator 120. The directional control valve 130 discharges the hydraulic fluid discharged by the actuator 120 to the tank 115. [ The directional control valve 130 adjusts the flow rate of the hydraulic fluid supplied from the pump device 11 to the actuator 120 and / or switches the flow direction. The directional control valve 130 is connected to the first pump 111, the second pump 112, the actuator 120 and the tank 115. The directional control valve 130 is disposed between the first pump 111 and the actuator 120 and between the second pump 112 and the actuator 120. In order to supply the operating fluid from the first pump 111 and the second pump 112 (two pumps) to the one actuator 120, one directional control valve 130 is sufficient, The valve 130 is unnecessary. A plurality of directional control valves 130 may be provided in the hydraulic system 101 for the construction machine (not shown). When a plurality of directional control valves 130 are provided, the plurality of directional control valves 130 are integrally formed, for example, in the form of a block (substantially rectangular parallelepiped). The plurality of directional control valves 130 may be collectively referred to as " directional control valves ".

The switching position of the directional control valve 130 is provided with a neutral position 130a (see FIG. 7), a first operating position 130b (see FIGS. 9 and 10) And a second operating position 130c (see Fig. 11). The directional control valve 130 of the present example includes a valve structure indicated by the symbol " D " in Fig. 6 when it is disposed in the first operating position 130b. In this valve configuration D, the pressure of the hydraulic fluid flowing through the second actuator passage 162, which will be described later, which is the hydraulic fluid discharged from the actuator 120, and the hydraulic fluid supplied from the pump device 11, The flow path configuration is determined depending on the magnitude and the magnitude of the pressure of the hydraulic fluid flowing through the oil passage.

That is, the "pressure of the hydraulic oil discharged from the actuator 120 in the second actuator passage 162 serving as the discharge passage" is smaller than the "pressure of the hydraulic oil supplied from the pump device 11 to the third supply passage 153" 6, the right valve structure of the valve structure indicated by the symbol " D " is adopted, the operating oil from the second actuator passage 162 is sent to the tank passage 145, and the first actuator passage (That is, returned). The passage connecting the second actuator passage 162 and the tank passage 145 is locally narrowed so that the second actuator passage 162 is moved from the second actuator passage 162 to the first actuator passage 161 The operating oil returns effectively. On the other hand, when the "pressure of the hydraulic oil supplied from the pump device 11 to the third supply passage 153" is equal to or larger than the "pressure of the hydraulic oil discharged from the actuator 120 to the second actuator passage 162" The operating fluid from the second actuator passage 162 is sent to the tank passage 145 but not to the first actuator passage 161 (that is, Not returned). In accordance with the magnitude relationship between the "pressure of the hydraulic oil supplied from the pump device 11 to the third supply passage 153" and the "pressure of the hydraulic oil discharged from the actuator 120 to the second actuator passage 162" It is determined whether or not the operating fluid discharged from the actuator 120 is sent to the actuator 120 (i.e., returned).

When the directional control valve 130 is disposed in the first operating position 130b, the unloading passages 141 and 142 are shut off, and the hydraulic fluid supplied from the pump device 11 is supplied to the third supply passage 153, The directional control valve 130 and the first actuator passage 161 to the actuator 120 (the first hydraulic oil port 121).

6, the third supply passage 153, the first actuator passage 161, the second actuator passage 162, and the third actuator passage 163 are disposed in the neutral position 130a, The unloading passages 141 and 142 are communicated and the hydraulic fluid supplied from the pump device 11 is sent to the tank 115 through the unloading passages 141 and 142. [

6, the third supply passage 153 is connected to the second actuator passage 162, and when the directional valve 130 is disposed in the second actuating position 130c, The passage 161 is connected to the tank passage 145, and the unloading passages 141 and 142 are shut off. Therefore, when the directional control valve 130 is disposed in the second operating position 130c, the actuator 120 is operated in the opposite direction to that in the case where the directional control valve 130 is disposed in the first operating position 130b .

The directional control valve 130 described above can be configured by a spool valve as shown in Fig. The spool valve is a valve that changes the flow rate and direction of the operating oil in accordance with the position (stroke position) of the spool 180 (below) relative to the spool hole 133 (below). The directional control valve 130 switches the switching position in accordance with the stroke position of the spool 180. 7, the direction switching valve 130 includes a switching valve body 131, a spool hole 133, passages 141 to 162, check valves 171 and 172, a spool 180 ).

The switching valve body 131 is a portion where the spool hole 133 and the passages 141 to 162 are formed. The switching valve main body 131 is block-shaped (massive).

The spool hole 133 is formed in (inside) the switching valve body 131 (inside). The spool hole 133 is a hole into which the spool 180 can be inserted.

The passages 141 to 162 are flow paths (flow paths, piping) through which the operating fluid flows. The passages 141 to 162 are formed in (inside) the switch valve body 131 (inside). A plurality of passages 141 to 162 are provided and a plurality of passages 141 to 162 are respectively connected to the spool holes 133 and opened in the spool hole 133. The openings of the passages 141 to 162 to the spool hole 133 extend in the peripheral direction of the spool hole 133, for example. The passages 141 to 162 are opened on the surface of the switching valve body 131 (not shown) so as to communicate with the outside of the switching valve body 131. The passages 141 to 162 include unloading passages 141 and 142 to which operating oil is supplied from the pump device 11, a tank passage 145 communicating with the tank 115, supply passages 151 to 153, And actuator passages 161 and 162, respectively.

The unloading passages 141 and 142 are bypass passages for returning the discharge hydraulic fluid of the pump device 11 shown in Fig. 5 to the tank 115 without supplying the actuator 120, (133). However, for example, when the unloading passages 141 and 142 and the other passages join (not shown), the hydraulic oil discharged from the actuator 120 may flow through the unloading passages 141 and 142. Further, for example, when the other passage is branched from the unloading passages 141 and 142 (not shown), the operating fluid may be supplied from the unloading passages 141 and 142 to the actuator 120. [ In this embodiment, a so-called dual bypass system is adopted and two unloading passages 141 and 142 (first unloading passage 141 and second unloading passage 142) are provided.

The first unloading passage 141 is connected to the first pump 111 and the operating fluid is supplied from the first pump 111. The first unloading passage 141 is connected to the tank 115. The first unloading passage 141 has an upstream first unloading passage 141a and a downstream first unloading passage 141b. The upstream first unloading passage 141a is a passage of the first unloading passage 141 upstream of the spool hole 133 (the first pump 111 side). The downstream first unloading passage 141b is a passage of the first unloading passage 141 downstream of the spool hole 133 (on the side of the tank 115).

The second unloading passage 142 is connected to the second pump 112, and the operating fluid is supplied from the second pump 112. The second unloading passage 142 is connected to the tank 115. The second unloading passage 142 has an upstream second unloading passage 142a and a downstream second unloading passage 142b. The upstream second unloading passage 142a is a passage of the second unloading passage 142 upstream of the spool hole 133 (the second pump 112 side). The downstream second unloading passage 142b is a passage of the second unloading passage 142 downstream of the spool hole 133 (on the side of the tank 115).

The tank passage 145 is connected to the tank 115 and is a passage for returning the operating oil discharged from the actuator 120 to the tank 115.

The supply passages 151 to 153 are paths for supplying the discharge operating fluid of the pump device 11 to the actuator 120. [ The supply passages 151 to 153 are provided with a first supply passage 151, a second supply passage 152 and a third supply passage 153.

The first supply passage 151 is a passage for supplying the discharge fluid of the first pump 111 to the actuator 120 (note that the third supply passage 153 is included in the first supply passage 151 . The first supply passage 151 is connected to the first pump 111. The first supply passage 151 is connected to the first unloading passage 141 (the first-side first unloading passage 141a). Connection of the first supply passage 151 to the first unloading passage 141 is performed outside the directional control valve 130 (may also be performed inside the directional control valve 130).

The second supply passage 152 is a passage for supplying the discharge operating fluid of the second pump 112 to the actuator 120 (provided that the third supply passage 153 is included in the second supply passage 152) . The second supply passage 152 is connected to the second pump 112. And the second supply passage 152 is connected to the second unloading passage 142 (the upstream second unloading passage 142a). The connection of the second supply passage 152 to the second unloading passage 142 is performed outside the directional control valve 130 (this can also be done inside the directional control valve 130).

The third supply passage 153 is a passage for supplying the discharge operating oil (at least one of the first pump 111 and the second pump 112) of the pump device 11 to the actuator 120. Hereinafter, at least one of the first pump 111 and the second pump 112 is referred to as a " pump apparatus 11 ". The third supply passage 153 is connected (communicated) to the first supply passage 151 and the second supply passage 152. In the third supply passage 153, a working oil in which the working oil flowing through the first supply passage 151 and the working oil flowing through the second supply passage 152 join together flows. Alternatively, only the operating oil flowing through one of the first supply passage 151 and the second supply passage 152 flows through the third supply passage 153. [ 7, the third supply passage 153 is provided with a first bridge passage 153a and a second bridge passage 153b, and the first bridge passage 153a and the second bridge passage 153b, Is connected (communicated) to at least one of the first supply passage 151 and the second supply passage 152. The first bridge passage 153a is a passage for supplying the discharge hydraulic fluid of the pump device 11 (see Fig. 5) to the first actuator passage 161. As shown in Fig. The second bridge passage 153b is a passage for supplying the discharge hydraulic fluid of the pump device 11 (see Fig. 5) to the second actuator passage 162. [

As shown in Fig. 5, the actuator passages 161 and 162 are passages for supplying the hydraulic fluid flowing through the third supply passage 153 to the actuator 120. As shown in Fig. The actuator passages 161 and 162 are connected to the actuator 120. The actuator passages 161 and 162 are provided with a first actuator passage 161 and a second actuator passage 162. [ The first actuator passage 161 is connected to the first hydraulic oil port 121. And the second actuator passage 162 is connected to the second hydraulic oil port 122.

The check valves 171 and 172 are valves for preventing backflow. The check valves 171 and 172 are provided with a first check valve 171 and a second check valve 172. The first check valve 171 is disposed in the first supply passage 151 and prevents back flow of the operating oil from the third supply passage 153 to the first supply passage 151. [ The second check valve 172 is disposed in the second supply passage 152 and prevents back flow of the operating oil from the third supply passage 153 to the second supply passage 152. [

The spool 180 is inserted into the spool hole 133 as shown in Fig. 7, and performs the same function as the valve body (refer to reference numeral 30 in Figs. 3 and 4) as described later. The spool 180 has a substantially cylindrical shape. The axial direction of the spool 180 (the direction of the center axis of the substantially cylindrical body) is defined as the spool axial direction A. One side in the spool axial direction A is referred to as one side A1 and the other side is referred to as the other side A2. The spool 180 is slidable (stroke) in the spool axial direction A with respect to the spool hole 133. 9 and 10 show a state in which the stroke position of the spool 180 (the position of the spool 180 with respect to the spool hole 133) is the position of the end of the other side A2 State). 11 shows a state in which the stroke position of the spool 180 is the position of the end of one side A1.

The spool 180 switches connection of the plurality of passages 141 to 162 shown in Fig. The spool 180 switches connection between the third supply passage 153 (the first supply passage 151 or the second supply passage 152) and the actuator passages 161 and 162. The spool 180 switches connection between the actuator passages 161 and 162 and the tank passage 145. [ The spool 180 switches connection between the upstream first unloading passage 141a and the downstream first unloading passage 141b. The spool 180 switches connection between the upstream side second unloading passage 142a and the downstream side second unloading passage 142b.

This spool 180 switches the connection between the passages 141 to 162 and the degree of opening (valve opening degree) of the connection. More specifically, the spool 180 sets the passages 141 to 162 to any one of the "blocked state" and the "connected state" (the "fully opened state" and the "throttled state"). Quot; blocked state " is a state in which the passages 141 to 162 are not connected (blocked state). The " connection state " is a state in which the passages 141 to 162 are connected (communicated). The " connection state " includes a " fully opened state " The " fully opened state " is a state in which the opening degree of the passage between the passages 141 to 162 is maximum (the opening degree varies when the spool 180 is caused to stroke from the end of one side A1 to the end of the other side A2, And the opening degree is the maximum). For example, the " fully opened state " is a state in which the flow paths of the passages 141 to 162 are not narrowed. The " throttling state " is a state in which the flow paths of the passages 141 to 162 are narrower than the above-mentioned " fully opened state "

The spool 180 includes a plurality of notches 181 and a plurality of land portions 183 as shown in Fig. The cut-away portion 181 and the land portion 183 are alternately arranged (formed) in the spool axial direction A.

The notch 181 connects the passages 141 to 162 shown in Fig. 7 (between passages). The cutout portion 181 (see Fig. 8) connects the openings of the passages 141 to 162 to the spool hole 133. Hereinafter, the opening into the spool hole 133 is referred to as " opening ". The notch portion 181 connects the passages 141 to 162 through the spool hole 133. [ As shown in Fig. 8, the notch 181 is a portion that dents inward in the radial direction of the spool 180 with respect to the land portion 183. A plurality of notches 181 are formed. The cutout portion 181 has a cutout portion 181a for the first unloading passage, a cutout portion 181b for the second unloading passage, a cutout portion 181c for the first actuator passage, (181d). The first unloading passage cutout portion 181a connects the upstream first unloading passage 141a and the downstream first unloading passage 141b. The second unloading passage cutout portion 181b connects the upstream second unloading passage 142a and the downstream second unloading passage 142b. The cutout portion 181c for the first actuator passage connects the third supply passage 153 (first bridge passage 153a) and the first actuator passage 161. [ The cutout portion 181d for the second actuator passage connects the third supply passage 153 (second bridge passage 153b) and the second actuator passage 162 with each other.

The land portion 183 is set in a state in which the passages 141 to 162 shown in Fig. 7 are not connected (shut-off state). The land portion 183 (see Fig. 8) prevents the passage 141-162 from being connected to each other by the notch 181 (see Fig. 8). The land portion 183 contacts the inner surface of the spool hole 133. [ The land 183 closes the openings of the passages 141-162. Alternatively, the land portion 183 closes the spool hole 133 between the different passages 141 - 162. The lands 183 bring the passages 141 to 162 into a contracted state. The land portion 183 narrows the opening of the passages 141 to 162 to be smaller than the fully opened state. As shown in Fig. 8, a plurality of land portions 183 are provided. The land portion 183 includes unloading passage land portions 183a, 183b, and 183c.

The unloading passage land portions 183a, 183b, and 183c are capable of shutting off the unloading passages 141 and 142 (it is possible to put them into a blocked state). The unloading passage land portions 183a, 183b and 183c are provided with a first unloading passage land portion 183a, a second unloading passage land portion 183b and a third unloading passage land portion 183c do. The first unloading passage land 183a has the first unloading passage 141 in a cutoff state or a contracted state (not shown) when it is the first operating position 130b shown in Figs. 9 and 10 . The second unloading passage land portion 183b has the second unloading passage 142 in a shutoff state or a throttling state (not shown) when it is the second operating position 130c shown in Fig.

The third unloading passage land 183c can block the first unloading passage 141 (see FIG. 11) and the second unloading passage 142 (see FIGS. 9 and 10) Used for dogs, can be common). The third unloading passage land portion 183c has the second unloading passage 142 in a blocked state or a contracted state (not shown) when it is the first operating position 130b shown in Figs. 9 and 10 . The third unloading passage land 183c has the first unloading passage 141 in a shutoff state or a throttling state (not shown) when it is the second operating position 130c shown in Fig.

The spool 180 of this embodiment has a passage switching portion 185 including the valve slider 32, the valve seal portion 51 and the valve base portion 50 already described with reference to Figs. The end portion of the other side A2 of the spool axial direction A among the end portions of the spool 180 (particularly the end portion of the other side A2 in the spool axial direction A than the cutout portion 181b for the second unloading passage) And the aforementioned valve hole 31 is formed in the end portion. The valve slider 32 is slidably disposed in the valve hole 31 and slidably moves on the peripheral wall of the valve hole 31. The valve base 50 is mostly disposed in the valve hole 31 and fixedly installed at the end of the other side A2 of the spool 180 so as to close the valve hole 31. [ The valve seal portion 51 is penetrated by the valve base portion 50 and is configured to seal between the peripheral wall of the valve hole 31 and the valve base portion 50, 50, respectively. Although not shown, a spring (elastic body) is provided between the valve slider 32 and the valve base 50, and the valve slider 32 is moved in the direction away from the valve base 50 The one side A1 of the spool axial direction A).

A through hole 43 penetrating through the valve slider 32 is formed between the end face of the valve slider 32 on one side A1 in the spool axial direction A and the end face on the other side A2. The end surface of the other side A2 of the valve slider 32 is supplied from the third supply passage 153 (second bridge passage 153b) to the valve hole 31, The second operating oil working portion 36 is formed.

A fourth connecting hole 54 communicating the outside of the spool 180 with the inside (that is, the valve hole 31) is formed in the wall portion of the spool 180 that forms the valve hole 31 therein, The sixth connecting hole 56 and the seventh connecting hole 57 are formed in order from the one side A1 to the other side A2 of the spool axial direction A. [ The sixth connection hole 56 is formed in the cutout portion 181d for the second actuator passage. The fourth connection hole 54 and the fifth connection hole 55 are formed at one side A1 in the spool axial direction A with respect to the second actuator passage cutout 181d so that the second unloading passage cutout portion 181b and the second And is formed in the land portion 183 between the cutouts 181d for the actuator passages. The seventh connection hole 57 is formed in the land portion 183 on the other side A2 of the spool axial direction A than the cutout portion 181d for the second actuator passage. The shape of the fourth connection hole 54, the fifth connection hole 55, the sixth connection hole 56, and the seventh connection hole 57 is not particularly limited.

(Arrangement of the passages 141 to 162)

The openings (openings in the spool hole 133) of the passages 141 to 162 shown in Fig. 7 are arranged in the order from one side A1 to the other side A2 of the spool axial direction A, for example, " tank passages 145, The first bridge passage 153a (the third supply passage 153 at one side A1), the unloading passages 141 and 142, the second bridge passage 153b (the third supply passage at the other side A2) (The passage 153), the second actuator passage 162, and the tank passage 145 of the other side A2. The opening of the tank passage 145 of the one side A1 and the opening of the tank passage 145 of the other side A2 communicate with each other inside the switching valve body 131 (the inside of the switching valve body 131 does not need to be communicated) .

(Arrangement of the unloading passages 141 and 142)

The unloading passages 141 and 142 are arranged as follows. The unloading passages 141 and 142 are disposed so as to suppress the dimension (the dimension of the spool 180) of the spool hole 133 (see FIG. 7) in the spool axial direction A from becoming excessively large. Specifically, it is as follows.

(In order of disposition of the unloading passages 141 and 142)

The unloading passages 141 and 142 are arranged so as to allow the third unloading passage land portion 183c to be used in common. Concretely, the first unloading passage 141 and the second unloading passage 142 are arranged so as to be adjacent to each other (adjacent to the spool axis direction A, hereinafter the same) (see " adjacent " For example, the first upstream unloading passage 141a and the second upstream unloading passage 142a are disposed adjacent to each other. For example, the downstream first unloading passage 141b and the first upstream unloading passage 141a are disposed adjacent to each other. For example, the upstream side second unloading passage 142a and the downstream side second unloading passage 142b are disposed adjacent to each other.

Here, the passage? And the passage? Are " adjacent to each other " is arranged in the following [placement example 1] or [placement example 2]. [Arrangement Example 1] No other passage (a passage other than the passage? And the passage?) Is disposed between the passage? And the passage?. In the spool hole 133 (see Fig. 7), the opening of another passage is not disposed between the opening of the passage a (opening into the spool hole 133) and the opening of the passage?. [Arrangement Example 2] The passage? And the passage? Are arranged in order in the spool axial direction A. More specifically, passage a is arranged next to passage a in the order from one side A1 to the other side A2 of the spool axial direction A (or passage a is arranged after passage a). In the spool hole 133 (see Fig. 7), the opening of the passage a and the opening of the passage [beta] are sequentially arranged in the spool axial direction A. [

(work)

The hydraulic system 101 for a construction machine shown in Fig. 5 operates as follows. The directional control valve 130 operates in accordance with the operation of the directional control valve 130 (operation by the operator of the construction machine, for example, lever operation). According to this operation, the direction switching valve 130 switches the neutral position 130a, the first operating position 130b, and the second operating position 130c. According to this operation, the spool 180 shown in Fig. 7 changes the stroke position. As a result, the spool 180 switches the connection between the passages 141 to 162 and the opening degree of the connection (valve opening degree). As a result, the directional control valve 130 adjusts the presence or absence of supply and discharge of the operating fluid to and from the actuator 120 and the flow rate of the operating fluid supplied to and discharged from the actuator 120.

(Neutral position 130a)

The direction switching valve 130 when the switching position is the neutral position 130a does not supply and discharge the operating oil to the actuator 120. [ When the switching position of the direction switching valve 130 is the neutral position 130a, the spool 180 is disposed at the second position in the spool hole 133 shown in Fig. 7, the direction switching valve 130, It works together. As shown in Fig. 7, the spool 180 disengages or interrupts the first unloading passage 141, and the direction switching valve 130 disengages the first unloading passage 141 from the fully opened state . More specifically, the first upstream unloading passage 141a and the first downstream unloading passage 141b are brought into a fully opened state through the first unloading passage cutout portion 181a (see FIG. 8). The operating oil flows from the upstream first unloading passage 141a to the downstream first unloading passage 141b. [Operation 1b] The spool 180 releases the blocking or opening of the second unloading passage 142, and the direction switching valve 130 brings the second unloading passage 142 into a fully opened state. Specifically, the directional control valve 130 opens the second upstream unloading passage 142a and the second downstream unloading passage 142b through the second unloading passage cutout portion 181b (see FIG. 8) State. The operating oil flows from the upstream-side second unloading passage 142a to the downstream-side second unloading passage 142b. [Operation 1c] The directional control valve 130 turns off the first bridge passage 153a. [Operation 1d] The directional control valve 130 brings the tank passage 145 into a shutoff state.

[Operation 1e] The second bridge passage 153b communicates with the valve hole 31 through the fourth connection hole 54 and the valve hole 31a through the fourth connection hole 54 from the second bridge passage 153b. 31) through the through hole (43) and acts on the second operating oil operating portion (36). Thereby, the valve slider 32 moves to one side A1 of the spool axial direction A (left side in Fig. 7). The fifth connection hole 55 is disposed between the second bridge passage 153b and the second actuator passage 162 and the sixth connection hole 56 is communicated with the second actuator passage 162, 7 connecting hole 57 is disposed between the second actuator passage 162 and the tank passage 145. [

[Operation 1f] As a result, the discharge hydraulic fluid of the pump device 11 shown in Fig. 5 is not supplied from the directional control valve 130 to the actuator 120. [ The spool 180 disposed at the second position disengages or interrupts the unloading passages 141 and 142 so that the discharge hydraulic fluid of the pump device 11 passes through the unloading passages 141 and 142 and flows into the tank 115) (see FIG. 5). [Operation 1g] The passage between the second actuator passage 162 and the second bridge passage 153b is blocked by the passage switching portion 185 (valve slider 32).

(First operating position 130b)

When the switching position is the first operating position 130b, the direction switching valve 130 supplies and discharges the operating fluid to and from the actuator 120. [ When the switching position of the direction switching valve 130 is the first operating position 130b, the spool 180 is disposed at the first position in the spool hole 133 shown in Figs. 9 and 10, 130) operate as follows. [Operation 2a] The spool 180 shuts off or throttles the first unloading passage 141, and the direction switching valve 130 sets the first unloading passage 141 to the shutoff state or the throttling state (not shown) . Specifically, the directional control valve 130 switches the first upstream unloading passage 141a and the first downstream unloading passage 141b to the closed state or the contracted state by the first unloading passage land portion 183a do. [Operation 2b] The spool 180 shuts off or throttles the second unloading passage 142, and the direction switching valve 130 sets the second unloading passage 142 to the shutoff state or the throttling state (not shown) . Specifically, the directional control valve 130 is switched between a closed state or a contracted state by the third unloading passage land portion 183c in the upstream side second unloading passage 142a and the downstream side second unloading passage 142b do. [Operation 2c] The directional control valve 130 brings the first bridge passage 153a (third supply passage 153) and the first actuator passage 161 into a connected state. Specifically, the cutout portion 181c for the first actuator passage formed in the spool 180 is connected to the first bridge passage 153a (the third feed passage 153) and the first actuator passage 161, The first bridge passage 153a (the third supply passage 153) and the first actuator passage 161 are connected through the cutout portion 181c for the first actuator passage. [Operation 2d] The spool 180 defines a passage (second connection passage) for connecting the second actuator passage 162 and the tank passage 145 by the second actuator passage cutout portion 181d, The valve 130 brings the second actuator passage 162 and the tank passage 145 into a connected state. [Operation 2e] As a result, the hydraulic fluid flowing through the first supply passage 151 and the second supply passage 152 joins at the third supply passage 153. [ The hydraulic fluid flowing through the third supply passage 153 is supplied to the actuator 120 (first hydraulic oil port 121; see FIG. 5) through the first actuator passage 161. As a result, the actuator 120 operates as one side.

[Operation 2f] Further, the fourth connection hole 54 is connected to the second bridge passage 153b, the fifth connection hole 55 is connected to the second actuator passage 162, and the sixth connection hole 56 Is disposed between the second actuator passage 162 and the tank passage 145 and the seventh connection hole 57 is connected to the tank passage 145. [

[Operation 2g] When the pressure of the hydraulic fluid flowing through the second actuator passage 162 is equal to or lower than the pressure of the hydraulic fluid flowing through the second bridge passage 153b, the valve slider 32 (The left side in Fig. 9) of the spool axial direction A to block the gap between the second actuator passage 162 and the second bridge passage 153b. The hydraulic oil discharged from the actuator 120 (the second hydraulic oil port 122) is supplied to the second actuator passage 162 and the second actuator passage cutout portion (second actuator passage) 162 without being sent to the second bridge passage 153b 181d (second connection passage 34) to the tank passage 145 and sent to the tank 115 (see FIG. 5). As described above, in this example, the second actuator passage 162 (discharge passage) communicates with the tank 115 (discharge tank) by the spool 180 (the cutout portion 181d for the second actuator passage) A flow path forming portion capable of forming the connection flow path 34 ".

[Operation 2h] On the other hand, when the "pressure of the hydraulic oil flowing through the second actuator passage 162" is larger than the "pressure of the hydraulic oil flowing through the second bridge passage 153b", as shown in FIG. 10, 32) is moved to the other side A2 (the right side in FIG. 10) of the spool axial direction A and the valve hole 31 is provided with a first connection hole 54 communicating with the fourth connection hole 54 and the fifth connection hole 55 (33) is formed. Therefore, the second actuator passage 162 and the second bridge passage 153b are connected to the fifth connection hole 55, the first connection passage 33 (valve hole 31), and the fourth connection hole 54 . The hydraulic fluid discharged from the actuator 120 (the second hydraulic oil port 122) flows into the tank passage 145 through the second actuator passage 162 and the cutout portion 181d for the second actuator passage, And is sent to the second bridge passage 153b through the fifth connection hole 55, the first connection passage 33 (valve hole 31) and the fourth connection hole 54 Loses. The operating fluid sent from the second actuator passage 162 to the second bridge passage 153b is sent back to the actuator 120 through the first bridge passage 153a and the first actuator passage 161, .

The pressure of the operating oil supplied from the second actuator passage 162 (discharge passage) to the valve hole 31 and the pressure of the operating fluid supplied from the second bridge passage 153b (supply passage) to the valve hole 31 The first connection passage 33 is defined by the flow path switching portion 185 (valve slider 32) of the directional control valve 130 in accordance with the magnitude relationship between the pressure and the pressure of the fluid. The second actuator passage 162 (discharge passage) and the tank passage 145 (the tank 115 (discharge tank)) are connected by the directional control valve 130 (the cutout portion 181d for the second actuator passage) (Second connection flow path) is defined. Therefore, the first connection passage 33, which can be used as the regeneration mechanism of the hydraulic oil, and the second connection passage, which can be used as the hydraulic oil discharge mechanism, can be integrally formed by the direction switching valve 130.

(The second operating position 130c)

The direction switching valve 130 when the switching position is the second operating position 130c supplies and discharges the operating oil to the actuator 120. [ At this time, the directional control valve 130 supplies and discharges the hydraulic fluid to and from the actuator 120 such that the actuator 120 is operated on the opposite side (the other side) to the case where the switching position is the first operating position 130b. When the switching position of the direction switching valve 130 is the second operating position 130c, the spool 180 is disposed at the third position in the spool hole 133 shown in Fig. 11, and the direction switching valve 130 Works as follows. [Operation 3a] As shown in Fig. 11, the directional control valve 130 sets the first unloading passage 141 to a shutoff state or a throttling state (not shown). Specifically, the directional valve 130 is connected to the upstream first unloading passage 141a and the downstream first unloading passage 141b by the third unloading passage land portion 183c (see Fig. 7) Shut off or throttled. [Operation 3b] The directional control valve 130 sets the second unloading passage 142 to a shutoff state or a throttling state (not shown). Specifically, the directional control valve 130 closes the second upstream unloading passage 142a and the downstream second unloading passage 142b by the second unloading passage land portion 183b (see FIG. 7) State or a throttling state. [Operation 3c] The directional control valve 130 turns off the first bridge passage 153a. Concretely, the first unloading passage land 183a blocks the first bridge passage 153a, and the first bridge passage 153a and the first actuator passage 161 are blocked. [Operation 3d] The directional control valve 130 brings the second bridge passage 153b (the third supply passage 153) and the second actuator passage 162 into a connected state. Specifically, the cutout portion 181d for the second actuator passage is connected to the second bridge passage 153b (third supply passage 153) and the second actuator passage 162, and the second actuator passage cut- The second bridge passage 153b (the third supply passage 153) and the second actuator passage 162 are connected via the first passage 181d. [Operation 3e] The directional control valve 130 brings the first actuator passage 161 and the tank passage 145 into a connected state. Specifically, the first actuator passage cutout portion 181c is connected to the first actuator passage 161 and the tank passage 145, and is connected to the first actuator passage 161 (not shown) through the cutout portion 181c for the first actuator passage And the tank passage 145 are connected to each other.

[Operation 3f] The fourth connection hole 54 is disposed between the second unloading passage 142 (the downstream second unloading passage 142b) and the second bridge passage 153b. The fifth connection hole 55 is connected to the second bridge passage 153b. The sixth connection hole 56 is connected to the second bridge passage 153b and the second actuator passage 162. [ The seventh connection hole 57 is connected to the second actuator passage 162. [

As a result, the hydraulic fluid flowing through the first supply passage 151 and the second supply passage 152 joins together in the third supply passage 153. [Operation 3g] As a result, The hydraulic fluid flowing through the third supply passage 153 (the second bridge passage 153b) flows through the second actuator passage cut-away portion 181d and the second actuator passage 162 to the actuator 120 Port 122; see Fig. 5). The hydraulic fluid discharged from the actuator 120 (the first hydraulic oil port 121) flows through the tank passage 145 through the first actuator passage 161 and the first actuator passage cutout portion 181c shown in Fig. And is sent to the tank 115 shown in Fig. As a result, the actuator 120 operates on the other side.

[Operation 3h] The second bridge passage 153b and the second actuator passage 162 are communicated through the cutout portion 181d for the second actuator passage and the second actuator passage 162b from the second bridge passage 153b , The " pressure of the hydraulic oil flowing through the second bridge passage 153b " becomes equal to or higher than " the pressure of the hydraulic oil flowing through the second actuator passage 162 ". In this case, the valve slider 32 moves to one side A1 (the left side in Fig. 11) of the spool axial direction A and the fifth connection hole 55, the sixth connection hole 56 and the seventh connection hole 57 (Closed).

The present invention is not limited to the above-described individual embodiments and modifications, but may be combined with each other, and various modifications may be added. Various additions, changes and omissions can be made without departing from the spirit and scope of the present invention, which is derived from the contents specified in the claims and their equivalents.

10: Hydraulic system
11: Pump device
12: Actuator
12a: head room
12b: Rod seal
13: Directional valve
14: First tank
15: Second tank
16: Check valve
20: Supply path
21: Unloading passage
22: exhaust passage
23: tank flow
30: valve body
31: valve hole
32: Valve slider
33: first connection channel
34: second connection channel
35: first operating oil operating portion
36: second operating oil operating portion
37: Cutout portion for connecting the discharge tank
38: first connection hole
39: second connection hole
40: third connection hole
41: Valve seat
42a: a first valve land portion
42b: the second valve land portion
43: Through hole
50: valve base
51: valve seal portion
54: fourth connection hole
55: fifth connection hole
56: sixth connection hole
57: seventh connecting hole
101: Hydraulic system for construction machinery
111: first pump
112: Second pump
115: tank
120: Actuator
121: First working oil port
122: second operating oil port
130: Directional switching valve
130a: Neutral position
130b: first operating position
130c: second operating position
131: Switching valve body
133: Spool hole
141: 1st unloading passage
141a: upstream side first unloading passage
141b: the first unloading passage on the downstream side
142: 2nd unloading passage
142a: upstream side second unloading passage
142b: downstream side second unloading passage
145: tank passage
151: first supply passage
152: second supply passage
153: third supply passage
153a: first bridge passage
153b: second bridge passage
161: first actuator passage
162: second actuator passage
171: first check valve
172: second check valve
180: spool (valve body)
181:
181a: cutout portion for the first unloading passage
181b: cutout portion for the second unloading passage
181c: cutout portion for the first actuator passage
181d: cutout portion for the second actuator passage
183:
183a: the first unloading passage land portion
183b: Land portion for the second unloading passage
183c: Land portion for the third unloading passage
185:

Claims (6)

A valve hole formed in the valve body,
A supply passage connected to the valve hole, the actuator and the pump device and supplied with operating fluid from the pump device,
A discharge passage connected to the actuator and the valve hole, through which the operating fluid is discharged from the actuator,
Wherein the valve hole is provided in a movable manner in the valve hole so as to be movable in the valve hole according to a pressure of the operating oil supplied from the supply passage to the valve hole and a pressure of operating oil supplied from the discharge passage to the valve hole When the pressure of the hydraulic fluid supplied from the discharge passage to the valve bore is larger than the pressure of the hydraulic fluid supplied from the supply passage to the valve bore, A valve slider disposed at a position defining the connecting flow passage in the valve hole,
And a flow passage forming portion capable of forming a second connection passage communicating the discharge passage and the discharge tank. The method according to claim 1,
Wherein the valve slider
The valve hole being movable in a first direction and a second direction,
A first hydraulic oil acting portion in which a force in a first direction acts by a hydraulic oil supplied from the discharge passage to the valve hole and a second hydraulic oil working portion in which a force in a second direction is applied by a hydraulic oil supplied from the supply passage to the valve hole (2) A directional valve having a hydraulic oil acting portion. 3. The method of claim 2,
Wherein the valve slider
And a discharge tank connection cutout portion constituting at least a part of the second connection flow passage,
When the pressure of the operating oil supplied from the discharge passage to the valve hole is larger than the pressure of the operating oil supplied from the supply passage to the valve hole, the pressure of the operating oil supplied from the discharge passage to the valve hole And restricts communication between the discharge passage and the cutout for connection to the discharge tank, as compared with a case where the pressure of the operating oil supplied to the valve hole is smaller than the pressure of the operating oil supplied to the valve hole. The method of claim 3,
Wherein the valve body is provided with a first connection hole, a second connection hole and a third connection hole communicating with the valve hole,
Wherein the first connection hole is connected to the discharge passage and guides the operating oil from the discharge passage to the first operating oil operating portion,
The second connection hole is connected to the discharge passage,
The third connection hole communicates with the discharge tank,
Wherein the valve slider
When the pressure of the operating oil supplied from the discharge passage to the valve hole is smaller than the pressure of the operating oil supplied from the supply passage to the valve hole, the cutout portion for connecting the discharge tank is connected to the second connection hole and the third connection hole And,
When the pressure of the operating oil supplied from the discharge passage to the valve hole is larger than the pressure of the operating oil supplied from the supply passage to the valve hole, the pressure of the operating oil supplied from the discharge passage to the valve hole And restricts communication between the second connection hole and the cutout for connection to the discharge tank, as compared with a case where the pressure of the hydraulic oil supplied to the valve hole is smaller than the pressure of the hydraulic oil supplied to the valve hole. 5. The method according to any one of claims 1 to 4,
Wherein the valve slider
When the pressure of the operating oil supplied from the discharge passage to the valve hole is smaller than the pressure of the operating oil supplied from the supply passage to the valve hole, the valve body is provided in the valve body forming the boundary between the supply passage and the valve hole To a first position in close contact with the valve seat,
When the pressure of the operating oil supplied from the discharge passage to the valve hole is larger than the pressure of the operating oil supplied from the supply passage to the valve hole, moves to a second position spaced from the valve seat. A direction changing valve according to any one of claims 1 to 5,
A pump device connected to the supply passage of the direction switching valve,
An actuator connected to the supply passage and the discharge passage of the direction switching valve,
And a discharge tank communicating with the second connection passage of the directional control valve.

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