KR102500484B1 - directional seated valve - Google Patents

Abstract

A directional control valve having a simple structure capable of changing the supply flow rate of hydraulic oil is provided. The valve body 31 includes a first branch passage 48 and a first parallel passage 46 communicating with the first pump 51, a second branch passage 49 communicating with the second pump 52, and It has a second parallel passage 47 and a bridge passage 43 which is a bridge passage 43 opened to the spool hole 33 and is divided into a confluence passage 45 and a communication passage 44. When the spool 32 is disposed in the first position, the merging passage 45 is connected to at least one of the first branch passage 48 and the first parallel passage 46, the second branch passage 49, and the second branch passage 49. It communicates with at least one of the two parallel passages 47. When the spool 32 is disposed in the second position, the communication passage 44 communicates with at least one of the first branch passage 48 and the first parallel passage 46 .

Description

directional seated valve

The present invention relates to a directional selector valve that regulates the flow of hydraulic oil.

[0002] A hydraulic circuit system is known that drives various actuators with hydraulic oil supplied from two pumps (i.e., hydraulic oil). In such a hydraulic circuit system, the operation of each actuator is controlled by regulating the flow of hydraulic oil from two pumps with a directional control valve.

Patent Literature 1 discloses a directional selector valve capable of selectively forming a plurality of types of passage patterns. In this directional selector valve, selective formation of a plurality of types of passage patterns is possible by arranging a check valve or stopper between each of the tandem passage and the parallel passage and the bridge passage.

Japanese Unexamined Patent Publication No. 2016-138619

In order to drive a heavy operating device such as a boom of a hydraulic excavator, a hydraulic cylinder with a large area is used as an actuator, and a large flow of hydraulic oil needs to be supplied to the hydraulic cylinder, especially during upward driving. For example, when raising a boom, it is necessary to supply hydraulic oil with a relatively large flow rate to a hydraulic cylinder in order to move the boom against gravity while ensuring sufficient speed. On the other hand, when the boom is lowered, since the phase energy of the boom can be used, it is sufficient to supply hydraulic oil with a relatively small flow rate to the hydraulic cylinder.

In this way, the flow rate of hydraulic oil required to drive the actuator is not necessarily constant, and changes depending on specific operating conditions. Therefore, it is preferable to adjust the flow rate of the hydraulic fluid supplied to the hydraulic cylinder by the aforementioned directional control valve according to the specific operating state of the actuator. However, it is not easy to realize such a directional control valve with a simple structure, and simple addition of flow passages, valves, stoppers and the like complicates the structure of the directional control valve and results in high cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a simple structured directional selector valve capable of changing the supply flow rate of hydraulic oil.

One aspect of the present invention is a valve body in which a spool hole is formed, a spool disposed in the spool hole, and a bridge passage formed in a bridge shape and opened to the spool hole, and a bridge divided into a merging passage and a communication passage by a blocking portion. A passage and a first flow path, a second flow path, a third flow path, and a fourth flow path formed in the valve body, the first flow path and the second flow path communicating with the first pump, and the third flow path and the fourth flow path It communicates with the second pump, and when the spool is disposed in the first position, at least either one of the first flow passage and the second flow passage and at least one of the third and fourth flow passages communicate with the confluence passage, and the spool When disposed in this second position, at least either one of the first flow passage and the second flow passage communicates with the communication passage.

The valve body has an actuator passage that is open to the spool hole and communicates with the actuator, and one of the first flow passage and the second flow passage and at least either one of the third and fourth flow passage communicate with the merging passage, and the communication passage is , communicated to the other side of the first flow passage and the second flow passage but not to the confluence passage, the spool changes the communication state and blocking state between the bridge passage and the actuator passage according to the arrangement position in the spool hole, and the spool When arranged in this first position, the spool cuts off between the communication passage and the actuator passage while making the merging passage communicate with the actuator passage through the spool hole, and when the spool is placed in the second position, the spool, The communication passage may be brought into communication with the actuator passage through the spool hole while blocking between the merging passage and the actuator passage.

Another aspect of the present invention includes a valve body having a spool hole and a spool disposed in the spool hole, the valve body comprising: a first unloading passage communicating with the first pump and a second unloading passage communicating with the second pump; a passage, a first supply passage communicating with the first pump, a second supply passage communicating with the second pump, an actuator passage open to the spool hole and communicating with the actuator, and a bridge passage opening to the spool hole; A first parallel region capable of forming a first parallel passage communicating the first supply passage and the bridge passage, a second parallel region capable of forming a second parallel passage communicating the second supply passage and the bridge passage, the first supply passage and a first branch passage communicating the bridge passage with any one of the first unload passages, and a second branch passage communicating the bridge passage with any one of the second supply passage and the second unload passage, wherein the bridge passage comprises: A merging passage communicating with one parallel passage and a second parallel passage, and a communication passage communicating with the first branch passage but not communicating with the merging passage, the spool, depending on the arrangement position in the spool hole, bridge passage and actuator The communication state and blocking state between the passages are changed, and when the spool is disposed in the first position, the spool blocks the communication passage and the actuator passage while communicating the merging passage to the actuator passage through the spool hole, and the spool When disposed in this second position, the spool relates to a directional selector valve that connects the communication passage to the actuator passage via the spool hole while blocking between the merging passage and the actuator passage.

The blocking portion may block one end of the communication passage while blocking one end of the confluence passage.

The actuator passage has a first actuator passage disposed closer to the merging passage among the merging passage and the communication passage, and a second actuator passage disposed closer to the merging passage among the merging passage and the communication passage, wherein the spool is in the first position; , the spool blocks the communication passage and the first actuator passage while communicating the merging passage to the second actuator passage through the spool hole, and when the spool is disposed in the second position, the spool, The communication passage may be communicated with the first actuator passage through the spool hole while blocking between the confluence passage and the second actuator passage.

When the spool is disposed at the third position, the spool may block between the merging passage and the actuator passage while blocking between the communication passage and the actuator passage.

The directional control valve includes a first check valve that prevents a reverse flow of hydraulic oil from the confluence passage to the second flow passage, a second check valve that prevents a reverse flow of hydraulic fluid from the confluence passage to the third passage, and a communication passage to the first flow passage. You may further provide at least any one of the 3rd check valve which prevents the backflow of the hydraulic fluid of this, and the 4th check valve which prevents the backflow of the hydraulic fluid from the merging passage to the 4th flow path.

The actuator may be a hydraulic cylinder.

The actuator may be an actuator for driving the boom.

ADVANTAGE OF THE INVENTION According to this invention, the directional selector valve which can change the supply flow rate of hydraulic oil can be realized with a simple structure.

1 is an external view schematically illustrating a typical configuration example of a hydraulic excavator.
Fig. 2 is a cross-sectional view of the directional control valve.
Fig. 3 shows a hydraulic circuit diagram of a hydraulic excavator, and particularly shows a case where the boom is raised by driving a hydraulic cylinder in a forward direction.
Fig. 4 shows a hydraulic circuit diagram of a hydraulic excavator, and particularly shows a case where a hydraulic cylinder is driven in a reverse direction to lower the boom.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of this invention is described with reference to drawings. Hereinafter, a case in which the present invention is applied to a hydraulic excavator, particularly to a directional selector valve used in a hydraulic circuit for driving a boom, will be described. However, the subject to which the present invention can be applied is not limited to a directional control valve used in a hydraulic excavator. For example, it is possible to apply the present invention also to construction machines other than hydraulic excavators and hydraulically driven equipment other than construction machines.

1 is an external view schematically illustrating a typical configuration example of a hydraulic excavator 10 .

The hydraulic excavator 10 generally includes a lower frame 11 having a crawler, an upper frame 12 provided to be able to pivot with respect to the lower frame 11, and a boom 14 installed on the upper frame 12 ), an arm 15 installed on the boom 14, and a bucket 16 installed on the arm 15. The hydraulic cylinders 18, 19, and 20 are actuators for booms, arms, and buckets, and drive the boom 14, arm 15, and bucket 16, respectively. When the upper frame 12 is turned, rotational driving force from the swing motor 13 is transmitted to the upper frame 12 . Further, when the hydraulic excavator 10 is driven, rotational driving force from the driving motor 17 is transmitted to the crawler of the lower frame 11 .

2 is a cross-sectional view of the directional control valve 30 . The directional selector valve 30 is a valve that regulates the flow of hydraulic oil supplied from a pump to an actuator and hydraulic oil discharged from the actuator, and can selectively form a desired passage pattern among a plurality of types of passage patterns. FIG. 2 shows a hydraulic cylinder 18, which is an actuator for driving the boom 14 shown in FIG. 1, and a directional selector valve 30 disposed between the first pump 51 and the second pump 52. there is. In addition, other actuators (for example, the hydraulic cylinder 19 for driving the arm 15 shown in FIG. 1 and / or the hydraulic cylinder 20 for driving the bucket 16) and the pump are disposed The directional selector valve may have a configuration similar to that of the directional selector valve 30 shown in FIG. 2 .

The directional control valve (30) includes a valve body (31) having a spool hole (33) and a spool (32) disposed in the spool hole (33).

The spool hole 33 is formed inside the valve body 31, and the spool 32 is slidably disposed. The slide driving method of the spool 32 is not particularly limited, and in order to slide the spool 32 in the spool hole 33 and place it at a desired position, for example, a mechanical, hydraulic pilot, or electromagnetic driving structure is oriented. The switching valve 30 can be employed. The spool 32 is a substantially cylindrical member inserted into the spool hole 33, and has a plurality of land portions disposed spaced apart from each other in the axial direction, and a plurality of cutout portions provided between the land portions. The outer circumferential diameter of each land portion substantially coincides with the inner circumferential diameter of the spool hole 33. The outer circumferential diameter of each cutout is smaller than the inner circumferential diameter of the spool hole 33. When each land part is disposed between passages opened to the spool hole 33 and described later, the spool hole 33 between these passages is blocked to block the flow of hydraulic oil. On the other hand, when each cutout is disposed between passages opened in the spool hole 33 and described below, they form flow passages connecting these passages to allow the flow of hydraulic fluid. In this way, the spool 32 can not only switch between connecting and blocking passages (i.e., presence/absence of connection), but also adjust the flow path opening degree (i.e., valve opening degree) between passages.

The valve body 31 is a block-shaped (massive) member, and includes a first unloading passage 34, a second unloading passage 35, a first supply passage 36, a second supply passage 37, and an actuator passage. (40), a bridge passage (43) and a tank passage (58). Hydraulic oil flows through these passages.

The first unload passage 34 communicates with the first pump 51 and the second unload passage 35 communicates with the second pump 52 . The first supply passage 36 communicates with the first pump 51 and the second supply passage 37 communicates with the second pump 52 . Specifically, flow passages extending from the first pump 51 diverge halfway, and one of the flow passages constitutes the first unloading passage 34 (especially the upstream first unloading passage 34a), and the other one The flow path of constitutes the first supply passage (36). Similarly, flow passages extending from the second pump 52 branch off on the way, one of the flow passages constitutes the second unloading passage 35 (especially the upstream second unloading passage 35a), and the other one of the flow passages constitutes the second supply passage 37.

The first unloading passage 34 has an upstream first unloading passage 34a and a downstream first unloading passage 34b, and the second unloading passage 35 has an upstream second unloading passage 35a and a downstream side. It has a second unload passage 35b. The upstream-side first unloading passage 34a and the upstream-side second unloading passage 35a are passages on the upstream side (that is, on the pump side) of the spool hole 33, and the downstream first unloading passage 34b and the downstream side The second unloading passage 35b is a passage downstream of the spool hole 33 (namely, on the tank side). Moreover, in this embodiment, the 1st unloading passage 34 and the 2nd unloading passage 35 are arrange|positioned adjacent to each other with respect to the axial direction of the spool 32. That is, the downstream first unloading passage 34b and the upstream second unloading passage 35a are disposed adjacent to each other, and the upstream first unloading passage 34a and the downstream first unloading passage 34b are adjacently disposed. , the upstream second unloading passage 35a and the downstream second unloading passage 35b are disposed adjacent to each other. By arranging the passages constituting the first unloading passage 34 and the second unloading passage 35 adjacently, the first unloading passage 34 and the second unloading passage 34 and the second unloading passage use a common land portion of the spool 32. The connection/disconnection of (35) can be switched, and the enlargement of the spool 32 and the spool hole 33 in the axial direction can be suppressed.

The 1st unloading passage 34 and the 2nd unloading passage 35 are passages (bypass passages) for returning the hydraulic oil from the 1st pump 51 and the 2nd pump 52 to a tank, without supplying it to an actuator. )am. In this embodiment, as shown in FIG. 2, each of the first unloading passage 34 and the second unloading passage 35 and the actuator passage 40 (that is, the first actuator passage 41 and the second actuator Between the passages 42, there is one or more land portions of the spool 32. Therefore, each of the first unloading passage 34 and the second unloading passage 35 does not communicate directly with the actuator passage 40 through the spool hole 33, and the first unloading passage 34 and There is no direct supply and discharge of hydraulic fluid from each of the second unloading passages 35 to the actuator passage 40 through the spool hole 33. However, for example, when other flow paths diverge from the first unloading passage 34 and the second unloading passage 35, hydraulic oil is supplied to the actuator from the first unloading passage 34 and the second unloading passage 35 It is possible. In this embodiment, the upstream second unloading passage 35a communicates with the second branch passage 49, and the hydraulic oil from the upstream second unloading passage 35a is passed through the second branch passage 49, the bridge It is possible to supply the hydraulic cylinder 18 via the passage 43 (particularly the confluence passage 45), the spool hole 33 and the actuator passage 40 (particularly the second actuator passage 42).

The 1st supply passage 36 and the 2nd supply passage 37 are passages for supplying the hydraulic oil from the 1st pump 51 and the 2nd pump 52 to an actuator. The first supply passage 36 and the second supply passage 37 are connected to the spool hole 33 via the bridge passage 43 without being directly connected to the spool hole 33 . Although the 1st supply passage 36 of this embodiment is directly connected to the 1st pump 51, it may be connected to the 1st pump 51 via the 1st unloading passage 34. Similarly, although the 2nd supply passage 37 of this embodiment is directly connected to the 2nd pump 52, it may be connected to the 2nd pump 52 via the 2nd unloading passage 35.

The bridge passage 43 is formed in a bridge shape and is opened to the spool hole 33, and includes a first parallel passage 46, a second parallel passage 47, a first branch passage 48 and a second branch passage ( 49) and the spool hole 33. The bridge passage 43 is a passage for supplying hydraulic oil to the hydraulic cylinder 18 through the spool hole 33 and the actuator passage 40 . When the bridge passage 43 is blocked by the land portion of the spool 32, the communication between the spool hole 33 and the actuator passage 40 and the bridge passage 43 is blocked, or the valve opening is restricted. The bridge passage 43 of the present embodiment has a communication passage 44 and a merging passage 45 that do not communicate with each other, and the communication passage 44 and the merging passage 45 are located at different positions from each other and have spool holes ( 33) is opened.

The actuator passage 40 opens to the spool hole 33 and communicates with a hydraulic cylinder 18 serving as an actuator for driving the boom 14 . The actuator passage 40 of the present embodiment has a first actuator passage 41 and a second actuator passage 42 . The first actuator passage 41 is disposed closer to the communication passage 44 among the confluence passage 45 and the communication passage 44, and is connected to the first port 18a of the hydraulic cylinder 18. The second actuator passage 42 is disposed closer to the merging passage 45 of the merging passage 45 and the communication passage 44, and is connected to the second port 18b of the hydraulic cylinder 18.

The first port 18a and the second port 18b of the hydraulic cylinder 18 are supply ports of hydraulic oil to the hydraulic cylinder 18 according to the flow of hydraulic oil determined based on the arrangement state of the spool 32. or as an outlet. In this embodiment, when the 1st port 18a functions as a discharge port and the 2nd port 18b functions as a supply port, the hydraulic cylinder 18 is driven forward, and the piston of the hydraulic cylinder 18 protrudes from the cylinder. On the other hand, when the first port 18a functions as a supply port and the second port 18b functions as an outlet port, the hydraulic cylinder 18 is driven in the reverse direction, so that the piston of the hydraulic cylinder 18 is drawn into the cylinder. do.

The tank passage 58 is a passage connected to the tank (refer to matching "59" in Figs. 3 and 4), and is a passage for returning the hydraulic fluid discharged from the hydraulic cylinder 18 to the tank. Specifically, depending on the arrangement of the spool 32, the tank passage 58 communicates with the first actuator passage 41 or the second actuator passage 42, or the first actuator passage 41 and the second actuator passage 42. It does not communicate with both of the two actuator passages 42.

In addition, the valve body 31 includes a first parallel region 53, a second parallel region 54, a first tandem region 55, and a second tandem region 56 in addition to the passages described above.

The first parallel region 53 is a region capable of forming a first parallel passage 46 that communicates the first supply passage 36 and the bridge passage 43 (particularly, the confluence passage 45). The second parallel region 54 is a region capable of forming a second parallel passage 47 that communicates the second supply passage 37 and the bridge passage 43 (particularly, the confluence passage 45). The first tandem area 55 is formed by either one of the first supply passage 36 and the first unload passage 34 (particularly the upstream first unload passage 34a) and the bridge passage 43 (particularly the communication passage ( 44) is a region in which a first branch passage 48 communicating with each other can be formed. The 1st branch passage 48 of this embodiment makes the 1st supply passage 36 and the communication passage 44 communicate. The second tandem area 56 is formed by either one of the second supply passage 37 and the second unloading passage 35 (particularly, the upstream second unloading passage 35a) and the bridge passage 43 (particularly, the joining passage ( 45) is a region in which the second branch passage 49 communicating with each other can be formed. In the second branch passage 49 of the present embodiment, the second unload passage 35 (ie, the upstream second unload passage 35a) and the merging passage 45 communicate with each other.

The valve body 31 is a blocking portion 50 disposed between the communication passage 44 and the merging passage 45 and divides the bridge passage 43 into the communication passage 44 and the merging passage 45. It has part 50. The blocking portion 50 closes one end of the communication passage 44 (right end in FIG. 2) while blocking one end of the confluence passage 45 (left end in FIG. 2). As a result, the communication passage 44 can communicate with the first branch passage 48 and the spool hole 33, but not with the merging passage 45. On the other hand, the merging passage 45 can communicate with the first parallel passage 46, the second parallel passage 47, the second branch passage 49, and the spool hole 33, but communicates with the communication passage 44. It doesn't work.

A first check valve 61 is disposed in the first parallel passage 46, a second check valve 62 is disposed in the second parallel passage 47, and a third check valve is disposed in the first branch passage 48. 63 is disposed, and a fourth check valve 64 is disposed in the second branch passage 49. The 1st check valve 61 is a valve which prevents the reverse flow of hydraulic oil from the merging passage 45 to the 1st parallel passage 46, and the pressure of the hydraulic oil in the 1st parallel passage 46 in the merging passage 45 When the hydraulic oil pressure in the first parallel passage 46 is greater than the hydraulic oil pressure, the first parallel passage 46 is not blocked, and when the hydraulic oil pressure in the first parallel passage 46 is smaller than the hydraulic oil pressure in the confluence passage 45, the first parallel passage 46 is block Similarly, the second check valve 62 is a valve that prevents the reverse flow of hydraulic oil from the merging passage 45 to the second parallel passage 47, and the fourth check valve 64 removes from the merging passage 45. It is a valve that prevents the reverse flow of hydraulic fluid to the second branch passage 49. On the other hand, the third check valve 63 is a valve that prevents a reverse flow of hydraulic oil from the communication passage 44 to the first branch passage 48, and the pressure of the hydraulic oil in the first branch passage 48 is reduced to the communication passage 44. When the hydraulic oil pressure in the first branch passage 48 is greater than the hydraulic oil pressure in the first branch passage 48, the first branch passage 48 is not blocked. .

In addition, each of the above-mentioned spool 32 and check valves 61, 62, 63, 64 is provided with respect to the valve main body 31 so that attachment and detachment is possible, and as needed, members other than the structure shown in FIG. 2 may be substituted with For example, another spool having a land portion and a cutout portion different from the spool 32 shown in FIG. 2 may be disposed in the spool hole 33 . In addition, instead of one or a plurality of check valves 61, 62, 63, 64, a member such as a stopper blocking the passage may be disposed. As a result, the directional selector valve 30 can selectively form various passage patterns, and exhibits excellent general-purpose performance. For example, with the directional control valve 30, it is possible to supply hydraulic oil to an actuator from only one pump or to supply hydraulic oil to an actuator from two pumps. In addition, it is also possible to flexibly change and determine which of parallel connection and tandem connection the connection mode of the flow path is to be made by the directional selector valve 30 . In addition, when it is desired to give priority to the supply of hydraulic oil to the flow path, it is also possible to form a restrictor structure at a corresponding location of the valve body 31 as needed.

In the directional control valve 30 having the above configuration, the spool 32 is positioned between the bridge passage 43 and the actuator passage 40 according to the arrangement position in the spool hole 33 (that is, the stroke position). It is possible to change the communication state and blocking state of the hydraulic fluid and change the flow direction of the hydraulic fluid.

For example, FIG. 2 shows a state in which the spool 32 is disposed in a neutral position (ie, "third position"). In this case, the spool 32 (particularly the land portion) blocks the communication passage 44 and the actuator passage 40 (that is, the first actuator passage 41 and the second actuator passage 42) while forming a confluence passage. 45 and the actuator passage 40 (ie, the first actuator passage 41 and the second actuator passage 42) are blocked. Thereby, the hydraulic oil from the 1st pump 51 and the 2nd pump 52 does not flow into the spool hole 33 from the bridge passage 43 (ie, the communication passage 44 and the merging passage 45), , does not flow into the actuator passage 40 (ie, the first actuator passage 41 and the second actuator passage 42), so the hydraulic cylinder 18 is placed in a neutral state. Moreover, in this case, each of the 1st actuator passage 41 and the 2nd actuator passage 42 is cut off from the other flow path, blocks hydraulic oil, and the state of the hydraulic cylinder 18 is maintained.

Further, in the spool hole 33, the spool 32 is moved from the neutral position in one axial direction (refer to "D1" in Fig. 2) to be placed in the first operating position (ie, "first position"), It may be moved from the neutral position to the other axial direction (refer to coincidence "D2" in Fig. 2) and disposed in the second operating position (ie "second position").

For example, when the spool 32 is disposed in the first operating position, the land portion of the spool 32 is disposed between the communication passage 44 and the first actuator passage 41, and the merging passage 45 and the second actuator passage 41 are disposed. A cutout of the spool 32 is disposed between the actuator passages 42 . In addition, a cutout of the spool 32 is disposed between the first actuator passage 41 and the tank passage 58, and a land portion of the spool 32 is disposed between the second actuator passage 42 and the tank passage 58. are placed As a result, the spool 32 connects the merging passage 45 to the actuator passage 40 (particularly the second actuator passage 42) through the spool hole 33, while the communication passage 44 and the actuator passage 40 ) (that is, the first actuator passage 41 and the second actuator passage 42) are blocked. In addition, at least one of the first branch passage 48 (first flow passage) and the first parallel passage 46 (second flow passage) (the first parallel passage 46 in this example), the second parallel passage ( 47) (third flow passage) and at least one of the second branch passage 49 (fourth flow passage) (at least the second branch passage 49 in this example) communicates with the merging passage 45. Thus, at least one of the first supply passage 36 and the first unload passage 34 (the first supply passage 36 in this example), the second supply passage 37 and the second unload passage 35 ), at least one of which (in this example, at least the second unloading passage 35) communicates with the confluence passage 45. Therefore, the hydraulic oil flowing into the confluence passage 45 from the first pump 51 through the first supply passage 36 and the first parallel passage 46, and the upstream second unloading passage from the second pump 52 Hydraulic fluid flowing into the merging passage 45 through 35a and the second branch passage 49 merges in the merging passage 45 and flows into the second actuator passage 42 through the spool hole 33 . Moreover, the 2nd parallel passage 47 is provided with the bridge part (refer FIG. 3) not shown. Therefore, the hydraulic fluid flowing into the merging passage 45 from the second supply passage 37 is limited in flow by the throttling portion of the second parallel passage 47 . Thereby, while hydraulic oil is supplied from the 2nd actuator passage 42, the hydraulic cylinder 18 discharges hydraulic oil to the tank passage 58 via the 1st actuator passage 41, and is driven forward. The drive in the forward direction as used herein means a drive for moving the boom 14 requiring a larger power in the upward direction, among the drives for moving the boom 14 in the vertical direction.

On the other hand, when the spool 32 is disposed in the second operating position, the cutout of the spool 32 is disposed between the communication passage 44 and the first actuator passage 41, and the merging passage 45 and the second A land portion of the spool 32 is disposed between the actuator passages 42 . In addition, a land portion of the spool 32 is disposed between the first actuator passage 41 and the tank passage 58, and a cutout portion of the spool 32 is disposed between the second actuator passage 42 and the tank passage 58. are placed Thereby, the spool 32 cuts off between the merging passage 45 and the actuator passage 40 (the first actuator passage 41 and the second actuator passage 42), and the communication passage through the spool hole 33. 44 is communicated with the actuator passage 40 (particularly the first actuator passage 41). Further, at least one of the first branch passage 48 (first flow passage) and the first parallel passage 46 (second flow passage) (the first branch passage 48 in this example) is the communication passage 44 is connected to Thus, at least one of the first unloading passage 34 and the first supply passage 36 (the first supply passage 36 in this example) communicates with the communication passage 44 . Therefore, the hydraulic oil flowing into the communication passage 44 from the first pump 51 through the first supply passage 36 and the first branch passage 48 passes through the spool hole 33 to the first actuator passage 41 ) is introduced into Thereby, while hydraulic oil is supplied from the 1st actuator passage 41, the hydraulic cylinder 18 discharges hydraulic oil to the 2nd actuator passage 42, and is driven in the reverse direction. The driving in the reverse direction here means a drive for moving the boom 14 requiring a smaller power in the lower direction among driving for moving the boom 14 in the vertical direction.

Next, the driving state of the 1st pump 51, the 2nd pump 52, the direction change valve 30, and the hydraulic cylinder 18 is demonstrated using the hydraulic circuit diagram of FIG.3 and FIG.4.

Fig. 3 shows a hydraulic circuit diagram of the hydraulic excavator 10, and particularly shows a case where the boom 14 is raised by driving the hydraulic cylinder 18 forward. Fig. 4 shows a hydraulic circuit diagram of the hydraulic excavator 10, and particularly shows a case where the boom 14 is lowered by driving the hydraulic cylinder 18 in the reverse direction. 3 and 4, not only the hydraulic circuit for the hydraulic cylinder 18 that drives the boom 14, but also the hydraulic circuit for the swing motor 13 and the hydraulic cylinder 19 that drives the arm 15 Hydraulic circuitry for the hydraulic circuit, and hydraulic circuitry for the hydraulic cylinder 20 that drives the bucket 16 is also shown. Hereinafter, since the hydraulic circuit of the hydraulic cylinder 18 that mainly drives the boom 14 will be described, the turning motor 13, the hydraulic cylinder 19 and the direction change valve 70 provided for the hydraulic cylinder 20, 71 and 72) are in a neutral state in FIGS. 3 and 4 .

When the boom 14 is raised by driving the hydraulic cylinder 18 forward, the spool 32 is placed in the first operating position as described above. In this case, the directional selector valve 30 has the circuit structure shown in FIG. 3, and the 1st pump 51 and the 2nd pump 52 and the hydraulic cylinder 18 are connected by the flow path indicated by the code|symbol "30b". do.

That is, the flow path extending from the first pump 51 branches on the way to form the first supply passage 36, and the first parallel passage 46 branching from the first supply passage 36 is the confluence passage 45. communicate with On the other hand, the upstream second unloading passage 35a is formed by the flow path extending from the second pump 52, and the second branch passage 49 branching from the upstream second unloading passage 35a is a merging passage ( 45) in communication. A throttling portion and a second check valve 62 are provided in the second parallel passage 47 branching from the second supply passage 37, and the second parallel passage 47 also communicates with the merging passage 45. . And the merging passage 45 communicates with the 2nd actuator passage 42, and the 2nd actuator passage 42 is connected to the 2nd port 18b of the hydraulic cylinder 18. Moreover, the 1st actuator passage 41 connected to the 1st port 18a of the hydraulic cylinder 18 communicates with the tank passage 58, and the tank passage 58 is connected to the tank 59.

According to the hydraulic circuit having the configuration described above, the hydraulic oil from the first pump 51 and the hydraulic oil from the second pump 52 are merged in the confluence passage 45, and the hydraulic fluid is supplied through the second actuator passage 42. supplied to cylinder 18. Moreover, the hydraulic fluid flowing out from the hydraulic cylinder 18 is discharged to the tank 59 via the 1st actuator passage 41 and the tank passage 58. As a result, the hydraulic cylinder 18 is driven forward, and the boom 14 can be raised.

Meanwhile, when the boom 14 is lowered by driving the hydraulic cylinder 18 in the reverse direction, the spool 32 is disposed in the second operating position as described above. In this case, the directional selector valve 30 has the circuit structure shown in FIG. 4, and the 1st pump 51 and the 2nd pump 52 and the hydraulic cylinder 18 are connected by the flow path indicated by the code|symbol "30c". do.

That is, the flow path extending from the first pump 51 branches on the way to form the first supply passage 36, and the first branch passage 48 branches from the first supply passage 36, and this first branch The passage 48 communicates with the first actuator passage 41 via the communication passage 44 . On the other hand, the passage extending from the second pump 52 is blocked by the directional control valve 30 and communicates with the actuator passage 40 (ie, the first actuator passage 41 and the second actuator passage 42) It doesn't work. And the 2nd actuator passage 42 is connected to the tank 59 via the tank passage 58.

According to the hydraulic circuit having the configuration described above, the hydraulic oil from the first pump 51 flows through the first supply passage 36, the first branch passage 48, the communication passage 44, and the first actuator passage 41. is supplied to the hydraulic cylinder 18 via , but the hydraulic oil from the second pump 52 is not supplied to the hydraulic cylinder 18 . Moreover, the hydraulic fluid flowing out from the hydraulic cylinder 18 is discharged to the tank 59 via the 2nd actuator passage 42 and the tank passage 58. As a result, the hydraulic cylinder 18 is driven in the reverse direction, and the boom 14 is lowered.

In addition, when the boom 14 is neither raised nor lowered, as described above, the spool 32 is disposed in a neutral position, and between the first pump 51 and the second pump 52 and the hydraulic cylinder 18 The flow path of is configured as shown by reference numeral "30a" in FIGS. 3 and 4 . That is, between the first pump 51 and the second pump 52 and the actuator passage 40 (that is, the first actuator passage 41 and the second actuator passage 42) is blocked by the direction change valve 30 And neither supply nor discharge of hydraulic fluid to the hydraulic cylinder 18 is performed.

As explained above, according to this embodiment, the supply flow rate of the hydraulic oil to the hydraulic cylinder 18 can be changed by the directional control valve 30 of a simple structure. In particular, in the directional selector valve 30 of the present embodiment, the hydraulic cylinder 18 operates only by dividing the bridge passage 43 into a communication passage 44 and a confluence passage 45 by the blocking portion 50. A desired amount of hydraulic oil according to the condition can be supplied to the hydraulic cylinder 18 . That is, when the hydraulic cylinder 18 is driven in the forward direction requiring a large flow of hydraulic oil, hydraulic oil is supplied to the hydraulic cylinder 18 from two pumps (ie, the first pump 51 and the second pump 52). can On the other hand, when the supply amount of hydraulic oil to the hydraulic cylinder 18 is sufficient at a small amount, the hydraulic oil can be supplied to the hydraulic cylinder 18 only from one pump (ie, the first pump 51).

In this way, it is possible to optimize the supply mode of hydraulic oil according to the driving state of the hydraulic cylinder 18, and thus energy efficiency can be improved.

In the embodiment described above, the direction select valve 30 for regulating the supply and discharge of hydraulic oil to the hydraulic cylinder 18 for driving the boom 14 has the configuration shown in FIG. 2, but other direction changes Valves 70, 71, 72 (specifically, directional control valves 71, 72 for regulating the supply and discharge of hydraulic oil to the hydraulic cylinders 19, 20 for driving the arm 15 and the bucket 16) You may have the structure shown in FIG.

The present invention is not limited to the above-described embodiments and modified examples. For example, various modifications may be added to each element of the above-described embodiments and modified examples. In addition, forms including components other than the above-mentioned components are also included in the embodiments of the present invention. In addition, forms in which some of the elements described above are not included are also included in the embodiments of the present invention. Therefore, the components included in each of the above-described embodiments and modified examples and embodiments of the present invention other than those described above may be combined, and forms relating to such combinations are also included in the embodiments of the present invention. In addition, the effects exhibited by the present invention are not limited to the above-mentioned effects, and unique effects according to the specific configuration of each embodiment can also be exhibited. In this way, various additions, changes, and partial deletions to each element described in the claims, specification, abstract, and drawings are possible without departing from the technical spirit and spirit of the present invention.

For example, the merging passage 45 is one of the first branch passage 48 and the first parallel passage 46, and at least one of the second parallel passage 47 and the second branch passage 49 You have to be connected. Moreover, the communication passage 44 should just communicate with the other of the 1st branch passage 48 and the 1st parallel passage 46. However, even in this case, the communication passage 44 does not communicate with the confluence passage 45.

10: hydraulic shovel
11: lower frame
12: upper frame
13: Slewing motor
14: Boom
15: cancer
16: Bucket
17: travel motor
18: hydraulic cylinder
18a: first port
18b: second port
19: hydraulic cylinder
20: hydraulic cylinder
30: directional control valve
30a: neutral position
30b: first operating position
30c: second operating position
31: valve body
32: spool
33: spool hole
34: first unload passage
34a: upstream first unload passage
34b: downstream first unload passage
35: second unload passage
35a: upstream second unload passage
35b: downstream second unload passage
36: first supply passage
37: second supply passage
40: actuator passage
41: first actuator passage
42: second actuator passage
43 bridge passage
44: communication passage
45 confluence passage
46: 1st parallel passage (2nd flow path)
47: 2nd parallel passage (3rd flow path)
48: first branch passage (first flow path)
49: second branch passage (fourth flow path)
50: blocking part
51: first pump
52: second pump
53: first parallel area
54: second parallel area
55: first tandem area
56: second tandem area
58: tank passage
59: tank
61: first check valve
62: second check valve
63: third check valve
64: fourth check valve
70: directional control valve
71: directional control valve
72: directional control valve

Claims (8)

A valve body having a spool hole;
a spool disposed in the spool hole;
A bridge passage formed in a bridge shape and opened to the spool hole, and divided into a merging passage and a communication passage by a blocking portion;
A first flow path, a second flow path, a third flow path, and a fourth flow path formed in the valve body,
The first flow path and the second flow path communicate with the first pump,
The third flow path and the fourth flow path communicate with the second pump,
When the spool is disposed in the first position, at least one of the first flow passage and the second flow passage and at least one of the third flow passage and the fourth flow passage communicate with the confluence passage;
When the spool is disposed in the second position, at least one of the first flow passage and the second flow passage communicates with the communication passage. The method according to claim 1, wherein the valve body has an actuator passage that is open to the spool hole and communicates with an actuator;
One of the first flow passage and the second flow passage and at least one of the third flow passage and the fourth flow passage communicate with the confluence passage,
The communication passage communicates with the other of the first flow passage and the second flow passage, but does not communicate with the merging passage;
The spool changes a communication state and a blocking state between the bridge passage and the actuator passage according to the arrangement position in the spool hole;
When the spool is disposed in the first position, the spool blocks between the communication passage and the actuator passage while communicating the merging passage to the actuator passage through the spool hole;
When the spool is disposed in the second position, the spool connects the communication passage to the actuator passage through the spool hole while blocking between the merging passage and the actuator passage. The directional selector valve according to claim 2, wherein the blocking portion blocks one end of the communication passage while blocking one end of the confluence passage. The method according to claim 2 or 3, wherein the actuator passage comprises: a first actuator passage disposed closer to the communication passage among the merging passage and the communication passage; having a second actuator passage disposed closer together;
When the spool is disposed in the first position, the spool blocks between the communication passage and the first actuator passage while communicating the merging passage to the second actuator passage through the spool hole;
When the spool is disposed in the second position, the spool changes direction to communicate the communication passage to the first actuator passage through the spool hole while blocking between the confluence passage and the second actuator passage valve. The direction according to claim 2 or 3, wherein when the spool is disposed in the third position, the spool blocks between the merging passage and the actuator passage while blocking between the communication passage and the actuator passage. diverter valve. The method according to claim 2 or 3, wherein a first check valve prevents a reverse flow of hydraulic oil from the confluence passage to the second flow passage, and a second check valve prevents a reverse flow of hydraulic fluid from the confluence passage to the third passage. At least one of a valve, a third check valve preventing a reverse flow of hydraulic oil from the communication passage to the first flow passage, and a fourth check valve preventing a reverse flow of hydraulic oil from the confluence passage to the fourth flow passage. A directional control valve provided. The directional control valve according to claim 2 or 3, wherein the actuator is a hydraulic cylinder. The directional control valve according to claim 2 or 3, wherein the actuator is an actuator for driving a boom.

Images