KR20060084349A - Hydraulic circuit - Google Patents

Abstract

When the divert valves for the boom and the bucket for the boom of the first system and the divert valve for the arm of the second system are operated simultaneously, the pressurized oil from the third pump can be efficiently applied to the first system and the second. By joining the system, work efficiency can be improved.

The first system has a boom diverting valve 22 and a bucket diverting valve 23 to which pressurized oil from the first pump 13 is supplied. The second system has a female divert valve 27 to which pressurized oil from the second pump 12 is supplied. The third system has another divert valve to which pressurized oil from the third pump 13 is supplied. The first confluence passage 31 can supply pressurized oil from the third pump 13 to the boom diverting valve 22 and the bucket diverting valve 23 of the first system, and the second confluence passage 32 Is able to supply pressurized oil from the 3rd pump 13 to the arm direction switching valve 27 of a 2nd system. Then, a third confluence passage capable of supplying the pressurized oil from the third pump 13 to the bucket direction change valve 23 of the first system is provided.

Bucket cylinder, cylinder, directional directional valve, arm directional valve, pump, pressurized oil, directional directional valve for bucket, third confluence passage, hydraulic circuit

Description

Hydraulic Circuit {HYDRAULIC CIRCUIT}

1 illustrates a hydraulic circuit according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a part of the hydraulic circuit shown in FIG. 1.

(Explanation of the sign)

1 Hydraulic circuit 11 1st pump

12 Second Pump 13 Third Pump

14 boom cylinder 15 bucket cylinder

17 Arm cylinder 22 Directional valve for boom

23 Directional valves for buckets 27 Directional valves for arms

30 confluence switching valve 31 first confluence passage

32 Second confluence passage 33 Third confluence passage

A first system supplied with pressurized oil from the first pump, supplied with a boom diverting valve and a bucket diverted valve, a pressurized oil from the second pump, a second system having an arm diverted valve, and a third It relates to a hydraulic circuit having a third system with another redirection valve to which pressurized oil from the pump is supplied.

Background Art Conventionally, as a hydraulic circuit of a construction machine, a first system having a divert valve supplied with pressurized oil from a first pump, a second system having a divert valve supplied with pressurized oil from a second pump, and a third pump It is known to have a 3rd system which has a directional valve to which pressurized oil from is supplied (refer patent document 1, 2). In the hydraulic circuits described in Patent Literatures 1 and 2, a conduit passage capable of supplying pressurized oil from the third pump to the directional valve of the first system and pressurized oil from the third pump to the directional valve of the second system There is a conduit for supplying. Moreover, in patent document 2, the boom direction control valve for boom cylinder control and the bucket direction control valve for bucket cylinder control as the direction switching valve of a 1st system are the arm direction switching valves for arm cylinder control as a direction switching valve of a 2nd system. A hydraulic circuit is provided.

(Patent Document 1) Japanese Unexamined Patent Application Publication No. 5-310134 (FIGS. 1 and 2)

(Patent Document 2) Japanese Unexamined Patent Publication No. 2003-301804 (Fig. 2)

However, in the hydraulic circuit of the structure of patent documents 1 and 2, when the 1st system is provided with the direction switching valve for booms and the bucket direction switching valve, and the 2nd system is equipped with the arm direction switching valve, a boom There has been a problem with the working efficiency when the actuators of the three cylinders, the bucket cylinders and the arm cylinders are simultaneously performed. That is, when the pressurized oil of the third pump is joined to the first system and the second system through respective confluence passages, three operations of the boom raising operation, the arm pulling operation, and the bucket excavation operation are simultaneously performed. Since the pressurized oil supplied decreases compared with an arm cylinder and a boom cylinder, there existed a problem that the balance of these three operating speeds fell, and the work efficiency fell.

The present invention has been made in view of the above fact, and when the directional valve for the boom, the bucket directional valve of the first system and the three directional valves for the female directional valve of the second system are operated simultaneously, the pressure from the third pump is increased. It is an object of the present invention to provide a hydraulic circuit capable of efficiently joining oil to a first system and a second system to improve work efficiency.

The hydraulic circuit according to the present invention is provided with pressurized oil from a first pump, and has a directional valve for boom that controls the supply of pressurized oil to the boom cylinder and a directional valve for bucket that controls the supply of pressurized oil to the bucket cylinder. A second system having a first system, an arm divert valve supplied with pressurized oil from the second pump and controlling supply of pressurized oil to the arm cylinder, and another diverter valve supplied with pressurized oil from the third pump; A first confluence passage capable of supplying a third system, pressurized oil from the third pump to the boom diverting valve and the bucket diverting valve of the first system, and pressurized oil from the third pump. It relates to a hydraulic circuit having a second confluence passage that can be supplied to the arm direction switching valve of the second system.

In addition, the hydraulic circuit according to the present invention has several features as follows to achieve the above object. That is, the hydraulic circuit of this invention is equipped with the following features individually or in combination suitably.

A first feature of the hydraulic circuit of the present invention for achieving the above object is to provide a third confluence passage capable of supplying pressurized oil from the third pump to the bucket divert valve of the first system.

According to this configuration, since the pressurized oil of the third pump can be supplied to the bucket direction change valve through the third confluence passage, the flow rate of the pressurized oil supplied from the third pump to the bucket cylinder can be increased. As a result, when simultaneous operation of the directional valve for the boom, the directional valve for the bucket, and the three directional valves for the arm is performed, the operating speed of the bucket cylinder is slower than the operating speed of the boom cylinder and the arm cylinder. You can restrain losing. Therefore, when the said three direction switching valves are operated simultaneously, the pressurized oil from a 3rd pump can be efficiently joined to a 1st system and a 2nd system, and work efficiency can be improved.

In addition, a second feature of the hydraulic circuit according to the present invention includes a confluence valve provided between the first confluence passage, the second confluence passage, and the third confluence passage, and the third pump. The confluence valve has a first position in which the first confluence passage, the second confluence passage, and the third confluence passage communicate with the third pump, and the first confluence passage communicates with the third pump. At the same time, the second confluence passage and a second position for interrupting the connection between the third confluence passage and the third pump, and switch to the first position when the directional valve of the second system is operated. It is.

According to this structure, when the 2nd system directional valve is operated, pressurized oil from a 3rd pump can be supplied to the directional valve for boom, the directional valve for bucket, and the 3 directional valve for arm. Done. At this time, since the pressurized oil from the third pump is supplied to the bucket direction change valve through the first confluence passage and the third confluence passage, it is possible to suppress the slow operation speed of the bucket cylinder.

Further, a third feature of the hydraulic circuit according to the present invention is that the merging valve is switched to the second position when only the direction switching valve of the first system is operated, and the direction switching valve and the first system of the first system are operated. When the direction change valve of the 2nd system is operated, it switches to the said 1st position.

According to this structure, when only the direction change valve of a 1st system is operated, since a joining valve is switched to a 2nd position, more pressurized oil is supplied to a 1st system via a 1st confluence | path passage, and the direction change for booms A case where the supply amount of pressurized oil is insufficient in the valve and the bucket direction changeover valve can be suppressed, and the work efficiency can be improved. When the divert valves of the first and second systems are operated, pressurized oil from the third pump can be supplied to the divert valves for the boom divert valve, the bucket divert valve, and the arm divert valve. Done. At this time, since the pressurized oil from the third pump is supplied to the bucket direction change valve through the first confluence passage and the third confluence passage, the operation speed of the bucket cylinder can be suppressed from slowing down.

Further, a fourth feature of the hydraulic circuit according to the present invention includes a first throttle provided on the third pump side rather than a branching position where the boom diverting valve and the bucket diverting valve diverge in the first confluence passage; And a second throttle provided between the branch position and the bucket direction switching valve in the first confluence passage, and a third throttle provided in the third confluence passage.

According to this constitution, when the confluence valve is in the first position, the supply of pressurized oil to the turn direction valve for the female through the second confluence passage and the turn valve for the female through the second confluence passage is performed by the first throttle. 1 Priority is supplied to supply of pressurized oil to the directional valve for boom through the confluence passage. Then, when the confluence valve is in the first position, the supply of pressurized oil to the female direction diverter valve via the second confluence passage is further supplied by the third throttle to the bucket divert valve through the third confluence passage. It will take priority over supply. When the confluence valve is in the second position, the supply of pressurized oil to the directional direction valve for boom through the first confluence passage is given priority over the supply of the pressurized oil to the bucket direction change valve by the second throttle. By providing such first to third throttles, the amount of pressurized oil supplied to each of the three directional valves when the directional directional valve, the bucket directional valve, and the female directional valve is operated simultaneously. The distribution of the pressurized oil supply to these two diverter valves when the divert valve for boom and the divert valve for buckets are operated simultaneously can also be optimized. Therefore, in each of these two operating states, it is possible to realize an optimal confluence distribution in which the pressurized oil from the third pump is efficiently joined to the first and second systems.

(The best form to carry out invention)

EMBODIMENT OF THE INVENTION Hereinafter, the best form for implementing this invention is demonstrated, referring drawings. 1 illustrates a hydraulic circuit applied to a construction machine as a hydraulic circuit according to an embodiment of the present invention. The construction machine to which this hydraulic circuit 1 is applied is a crawler vehicle provided with various actuators, such as a boom and an arm, and is equipped with each hydraulic motor and each cylinder which drive them. And this construction machine is the 1st pump 11 (P1), the 2nd pump 12 (P2) which respectively supply pressurized oil to each of the 1st-3rd system provided in the hydraulic circuit 1, And third pump 13 (P3).

As shown in FIG. 1, the hydraulic circuit 1 includes a first system having a plurality of directional valves 21, 22, and 23 through which pressurized oil from the first pump 11 is supplied through the switching valve 20. And a second system having a plurality of directional valves 24, 25, 26, 27 from which the pressurized oil from the second pump 12 is supplied through the switching valve 20, and from the third pump 13. A third system having a plurality of directional valves 28 and 29 to which pressurized oil is supplied is provided.

The first system includes a left travel directional valve 21 for controlling the supply of pressurized oil to the left travel motor, and a boom directional valve 22 for controlling the supply of pressurized oil to the boom cylinder 14 for operating the boom. And a bucket direction switching valve 23 for controlling the supply of pressurized oil to the bucket cylinder 15 for operating the bucket. The boom directional valve 22 and the bucket directional valve 23 are connected in para (parallel), and these directional valves 22 and 23 and the left traveling directional valve 21 are in tandem (serial). Connected.

The second system is configured to control the supply of pressurized oil to the right direction change valve 24 for controlling supply of pressurized oil to the right drive motor and the boom swing (B / swing) cylinder 16 for boom swing operation. A boom swing directional valve 25, a service directional valve 26, and an arm directional valve 27 for controlling supply of pressurized oil to the arm cylinder 17 for operating the arm are provided. The service diverting valve 26 and the female diverting valve 27 are connected to para, and these diverting valves 26 and 27, the directional swing valve 25 for the boom swing, and the right turning valve 24 ) Is connected in tandem.

In the third system, a blade diverting valve 28 for controlling the supply of pressurized oil to the blade cylinder 15 for operating the blade and a turning diverting valve 29 for controlling the supply of pressurized oil to the swing motor are provided. It is provided. The blade directional valve 28 and the swing directional valve 29 are connected by para. In addition, these direction switching valves 28 and 29 comprise the other direction switching valve of the 3rd system in this embodiment.

In addition, the hydraulic circuit 1 includes a first joining passage 31, a second joining passage 32, a third joining passage 33, and a joining valve 30. The 1st confluence path 31 is comprised so that the pressurized oil from the 3rd pump 13 may join the 1st system, and may supply to the boom diverting valve 22 and the bucket directional valve 23. The second confluence passage 32 is configured to allow the pressurized oil from the third pump 13 to join the second system and to be supplied to the female direction change valve 27. The third confluence passage 33 is configured to allow the pressurized oil from the third pump 13 to join the first system and to be supplied to the bucket switching valve.

The merging valve 30 is provided between the merging passages of the three first merging passages 31, the second merging passages 32, and the third merging passages 33, and the third pump 13. As shown in the enlarged view of FIG. 2, this confluence valve 30 is switched between the first position 30a and the second position 30b. The switching between the first position 30a and the second position 30b is to be switched in accordance with the operation of the direction switching valve of the hydraulic circuit 1, as will be described later. When the merging valve 30 is switched to the first position 30a, the merging passages of the first merging passage 31, the second merging passage 32, and the third merging passage 33 are the third It is made to communicate with the pump 13. When the confluence valve 30 is switched to the second position 30b, the first confluence passage 31 and the third pump 13 communicate with each other, and the second confluence passage 32 and the third confluence together. The passage 33 and the third pump 13 are shut off.

1 and 2, the hydraulic circuit 1 includes a first throttle 34, a second throttle 35, and a third throttle 36. The first throttle 34 is provided on the third pump 13 side than the branching position 37 where the boom diverting valve 22 and the bucket diverting valve 23 branch in the first confluence passage 31. have. In this hydraulic circuit 1, the first throttle 34 is incorporated into the confluence valve 30 and formed. The second throttle 35 is provided between the branching position 37 and the bucket direction switching valve 23 in the first confluence passage 31. The third throttle 36 is provided in the third confluence passage 33.

Next, the structure and operation | movement which switch the confluence valve 30 are demonstrated. FIG. 1 shows a state in which the confluence valve 30 is switched to the first position 30a. The confluence valve 30 has been operated by an arm directional valve 27 which is a directional valve of the second system. At this time, it is comprised so that it may switch to the 1st position 30a. That is, when the pilot signal Pa3 of the arm pulling operation command is lowered and the arm direction switching valve 27 is switched operation (pilot pressure is applied to one of the pilot chambers and the arm direction switching valve 27 is switched position 27a). ), The pilot flow path 38 is formed so that the pilot pressure of the pilot signal Pa3 also acts on the confluence valve 30 to switch to the first position 30a.

Moreover, the confluence valve 30 is comprised so that it may switch to 2nd position 30b when only the boom direction change valve 22 which is a direction change valve of a 1st system was operated. That is, when the pilot signal Pa8 of the boom raising operation is lowered and only the boom direction switching valve 22 is switched to operate (the pilot pressure acts on one pilot chamber so that the boom direction switching valve 22 is switched position 22a). Pilot flow paths 39a and 39b are formed so that the pilot pressure of the pilot signal Pa8 also acts on the confluence valve 30 to switch to the second position 30b when only an operation to be switched to is performed). . In this way, the pressurized oil from the third pump 13 is joined to the first system via the first confluence passage 31 in the boom raising operation, which is the operation requiring the highest operating pressure. ) Can be supplied.

When the arm direction switching valve 27 and the boom direction switching valve 22 are operated, that is, when the pilot signal Pa3 for the arm pulling operation and the pilot signal Pa8 for the boom raising operation are simultaneously lowered, The joining valve 30 is comprised so that it may switch to the 1st position 30a. In the confluence valve 30, the hydraulic pressure area in the pilot chamber in which the pilot pressure of the pilot signal Pa3 acts, and the hydraulic pressure area in the pilot chamber in which the pilot pressure of the pilot signal Pa8 acts. It is formed so that it may become the same, and when the pilot signals Pa3 and Pa8 act simultaneously, it switches to the 1st position 30a by the spring force of the spring 30c.

Further, when switching from the first position 30a to the second position 30b, the opening area of the first throttle 34 is changed linearly in accordance with the pilot pressure of the pilot signal Pb8 in the boom lowering operation. The confluence valve 30 is formed.

In the hydraulic circuit 1 described above, since the third confluence passage 33 is provided, the pressurized oil of the third pump 13 can be supplied to the bucket direction change valve 23, and the third pump ( It is possible to increase the flow rate of the pressurized oil supplied from the 13 to the bucket cylinder 15. Thereby, the operation speed of the bucket cylinder 15 when the simultaneous operation of three directional valves for the boom directional valve 22, the bucket directional valve 23, and the arm directional valve 27 is performed. Can be suppressed from being slower than the operating speeds of the boom cylinders 14 and the arm cylinders 17. Therefore, when the said three direction switching valves are operated simultaneously, the pressurized oil from the 3rd pump 13 can be efficiently joined to a 1st system and a 2nd system, and work efficiency can be improved.

Moreover, in the hydraulic circuit 1, when the arm direction switching valve 27 of the 2nd system was operated, the boom direction switching valve 22, the bucket direction switching valve 23, and the arm direction switching valve 27 Pressurized oil from the third pump 13 can be supplied to the three directional valves of the pump. At this time, since the pressurized oil from the third pump 13 is supplied to the bucket direction change valve 23 through the first confluence passage 31 and the third confluence passage 33, the bucket cylinder 15 The operation speed of can be suppressed from slowing down.

In the hydraulic circuit 1, when only the boom direction switching valve 22 of the first system is operated, since the joining valve 30 is switched to the second position 30b, the first joining passage 31 is closed. Through this, more pressurized oil is supplied to the first system, and the supply amount of pressurized oil can be suppressed from the boom diverting valve 22 and the bucket diverting valve 23, thereby improving the work efficiency. Can be. And when the directional diverting valve 22 for booms of the 1st system and the female directional valve 27 of the 2nd system were operated, the boom diverting valve 22, the bucket directional valve 23, and the arm direction Switch valve 27 The pressurized oil from the third pump 13 can be supplied to the three directional valves. At this time, since the pressurized oil from the third pump 13 is supplied to the bucket direction change valve 23 through the first confluence passage 31 and the third confluence passage 33, the bucket cylinder 15 The operation speed of can be suppressed from slowing down.

Moreover, in the hydraulic circuit 1, when the confluence valve 30 is in the 1st position 30a, the female directional valve 27 via the 2nd confluence path 32 is carried out by the 1st throttle 34. As shown in FIG. And the supply of pressurized oil to the bucket diverting valve 23 through the third confluence passage 33 takes precedence over the supply of pressurized oil to the boom diverting valve 22 through the first confluence passage 31. When the confluence valve 30 is in the first position 30a, the supply of pressurized oil to the female direction change valve 27 through the second confluence passage 32 is further controlled by the third throttle 36. The supply of pressurized oil to the bucket direction switching valve 23 through the three confluence passages 33 takes precedence. When the confluence valve 30 is in the second position 30b, the supply of pressurized oil to the boom direction switching valve 22 through the first confluence passage 31 is performed by the second throttle 35 for the bucket. Priority is given to supply of pressurized oil to the directional valve 23. By providing such a 1st throttle 34, 2nd throttle 35, and 3rd throttle 36, the directional diverting valve 22, the bucket directional valve 23, and the female directional valve 27 are provided. When the three directional valves are operated simultaneously, the distribution of the pressurized oil supply to each of the three directional valves can be optimized, and the boom directional valve 22 and the bucket directional valve 23 are The distribution of the pressurized oil supply amount to these two direction switching valves at the time of simultaneous operation can also be optimized. Therefore, in each of these two operating states, it is possible to realize an optimal confluence distribution in which the pressurized oil from the third pump 13 is efficiently joined to the first and second systems.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change is possible as long as it is described in a claim. For example, it may be changed as follows.

In this embodiment, the case where the confluence valve 30 is switched to the second position 30b when the boom directional valve 22 is operated so that the boom raising operation is performed has been described as an example. Various forms can be selected about the switching form of (s). For example, when the operation of the direction change valve is performed such that a bucket dump operation, a bucket excavation operation, a boom lowering operation, or the like is performed, the confluence valve 30 may be interlocked so as to be switched. In addition, the joining valve 30 may be switched in conjunction with all or part of the direction switching valve.

The present invention efficiently operates pressurized oil from a third pump when the divert valves for the boom and the bucket for the first system, the diverter valve for the bucket for the first system, and the three diverter valves for the arm for the second system are operated at the same time. And the second system can provide a hydraulic circuit capable of improving work efficiency.

Claims (4)

A first system, to which pressurized oil from a first pump is supplied, having a boom directional valve for controlling the supply of pressurized oil to the boom cylinder and a bucket directional valve for controlling the supply of pressurized oil to the bucket cylinder; A second system which is supplied with pressurized oil from the second pump and has a female direction diverter valve for controlling supply of pressurized oil to the arm cylinder; A third system having another diverting valve to which pressurized oil from the third pump is supplied; A first confluence passage for supplying pressurized oil from the third pump to the boom diverting valve and the bucket diverting valve of the first system; In the hydraulic circuit provided with the 2nd confluence path which can supply the pressurized oil from the said 3rd pump to the said arm directional valve of a said 2nd system, And a third confluence passage for supplying pressurized oil from the third pump to the bucket direction change valve of the first system. The confluence valve according to claim 1, further comprising: a confluence valve provided between the first confluence passage, the second confluence passage, and the third confluence passage, and the third pump; The confluence valve, A first position in which the first confluence passage, the second confluence passage, and the third confluence passage communicate with the third pump, and the first confluence passage and the third pump communicate with each other; A joining passage and a second position for interrupting between the third joining passage and the third pump, The hydraulic circuit characterized in that the switch to the first position when the direction switching valve of the second system is operated. The flow control valve according to claim 2, wherein the merging valve is switched to the second position when only the direction switching valve of the first system is operated, and the direction switching valve of the first system and the direction switching valve of the second system are operated. And the hydraulic circuit is switched to the first position. The first throttle according to claim 2 or 3, wherein the first throttle is provided on the third pump side rather than a branching position where the diverting valve for the boom and the diverting valve for the bucket diverge in the first confluence passage; A second throttle installed between the branch position and the bucket diverting valve in the first confluence passage; And a third throttle installed in the third confluence passage.

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