JP6290644B2 - Hydraulic drive - Google Patents

Description

  Embodiments described herein relate generally to a hydraulic drive device.

  As a hydraulic actuator mounted on a construction machine, for example, a hydraulic excavator, there are a hydraulic cylinder that drives a boom, an arm, a bucket, and the like, and a hydraulic motor that drives a cab (swivel body), a traveling caterpillar, and the like. A hydraulic drive device for driving these hydraulic actuators is provided to correspond to a variable displacement hydraulic pump (hereinafter simply referred to as a hydraulic pump) that discharges pressure oil, and the pressure discharged from the hydraulic pump. A hydraulic control valve group that supplies oil to each hydraulic actuator by controlling the flow rate. The hydraulic control valve group is provided with a plurality of switching valves, and these switching valves and a hydraulic actuator are connected to each other. Each switching valve is connected to the hydraulic pump via a tandem bypass passage through which pressure oil flows and a parallel bypass passage branched from the tandem bypass passage.

  Here, the hydraulic drive device mounted on the construction machine usually includes two hydraulic pumps, and the hydraulic control valve group often includes two hydraulic pumps corresponding to the number of hydraulic pumps. In this way, the pressure oil is supplied to each hydraulic actuator using two hydraulic pumps, and the pressure oil discharged from each hydraulic pump is merged and supplied to a desired hydraulic actuator as necessary. Operability is improved.

  In addition, as a hydraulic drive device mounted on a construction machine, there are some which include three hydraulic pumps and three hydraulic control valve groups. In this case, one of the three hydraulic pumps and the hydraulic control valve group is used exclusively for a hydraulic actuator (hydraulic motor) for turning the cab, which has a particularly high driving frequency. The other two hydraulic pumps and the hydraulic control valve group are used for driving a hydraulic actuator other than the hydraulic actuator for turning the cab, thereby reducing the burden on each hydraulic pump. As a result, the operability of the construction machine is further improved.

  Incidentally, in recent years, there has been a demand for further improvement in operability of construction machines without increasing the size of the hydraulic drive device.

Fujikoshi Technical Report Vol. 56 No. 2 Volume 121, [Search on December 9, 2013], Internet, <URL: http://www.nachi-fujikoshi.co.jp/tec/pdf/121/121-02.pdf>

  The problem to be solved by the present invention is to provide a hydraulic drive device capable of improving the operability of a construction machine while suppressing an increase in size of the device.

  The hydraulic drive device according to the embodiment has at least three hydraulic pumps and at least three hydraulic control valve groups corresponding to the number of hydraulic pumps. The hydraulic pump discharges pressure oil. The hydraulic control valve group controls the flow rate of the pressure oil discharged from the hydraulic pump, and supplies the pressure oil to the hydraulic actuator of the construction machine including the turning function. Each hydraulic control valve group has at least one switching valve to which a hydraulic actuator is connected. One of the hydraulic control valve groups is configured for turning drive in which one switching valve is connected to a hydraulic actuator for turning drive of the construction machine. Further, the hydraulic control valve group having the switching valve for turning drive is configured as an auxiliary supply for supplying pressure oil to the other hydraulic control valve group by a switching valve other than the turning drive.

The schematic block diagram which shows the hydraulic drive device of embodiment. The perspective view which shows the hydraulic control valve group of embodiment.

  Hereinafter, a hydraulic drive device of an embodiment is explained with reference to drawings.

FIG. 1 is a schematic configuration diagram of a hydraulic drive device.
As shown in the figure, the hydraulic drive device 1 is mounted on, for example, a hydraulic excavator and includes a plurality of hydraulic actuators 2. Further, a hydraulic pump (variable displacement hydraulic pump) 4 for supplying desired hydraulic oil to each hydraulic actuator 2 is provided. Further, a hydraulic control valve group 5 is provided between the hydraulic actuator 2 and the hydraulic pump 4 and controls the flow rate of the pressure oil supplied to the hydraulic actuator 2.

  In addition, the hydraulic drive device 1 includes an operation unit, a pump control unit (both not shown), and the like. The operation unit outputs an operation signal of each hydraulic actuator 2, and this output signal is input to the hydraulic control valve group 5 and the pump control unit. In the hydraulic control valve group 5, operation signals are input to switching valves 17a to 37e described later, and the switching valves 17a to 37e are driven based on the operation signals. The pump control unit performs drive control of the hydraulic pump 4 based on the operation signal.

  Here, the hydraulic drive apparatus 1 includes three hydraulic pumps 4 (a first hydraulic pump 4a, a second hydraulic pump 4b, and a third hydraulic pump 4c), and corresponds to the hydraulic pumps 4a, 4b, and 4c. As described above, three hydraulic control valve groups 5 (a first hydraulic control valve group 5a, a second hydraulic control valve group 5b, and a third hydraulic control valve group 5c) are provided. The three hydraulic control valve groups 5 are arranged in the order of the first hydraulic control valve group 5a, the second hydraulic control valve group 5b, and the third hydraulic control valve group 5c. In other words, the second hydraulic control valve group 5b is disposed between the first hydraulic control valve group 5a and the third hydraulic control valve group 5c. The hydraulic actuator 2 is connected to the first hydraulic control valve group 5a and the third hydraulic control valve group 5c arranged on both sides.

The plurality of hydraulic actuators 2 includes an arm driving hydraulic cylinder 2a, a cab turning hydraulic motor 2b, a bucket driving hydraulic cylinder 2c, a boom driving hydraulic cylinder 2d, and two driving hydraulic motors 2e and 2f. Etc.
In the present embodiment, the first hydraulic control valve group 5a includes an arm driving hydraulic cylinder 2a, a cab turning hydraulic motor 2b, and one of the two traveling driving hydraulic motors 2e and 2f. Is connected. Further, the third hydraulic control valve group 5c is connected to the hydraulic cylinder 2c for driving the bucket, the hydraulic cylinder 2d for driving the boom, and the other hydraulic motor 2f of the two hydraulic motors 2e, 2f for driving. ing.

FIG. 2 is a perspective view of the hydraulic control valve group.
As shown in FIGS. 1 and 2, the first hydraulic control valve group 5 a has a rectangular parallelepiped first housing 13 a. In this first housing 13a, four switching valves (spools) 17a, 17b, 17c, 17d for adjusting the flow rate of the pressure oil to each hydraulic actuator 2 are slidable (slidable in the vertical direction in FIG. 2). And substantially parallel to each other. Each switching valve 17a-17d is what is called an open center type switching valve. The pressure oil supplied from the first hydraulic pump 4a passes through a first tandem bypass passage 8a formed in the first housing 13a and a first parallel bypass passage 9a branched from the first tandem bypass passage 8a, 7 is connected.

The first housing 13a is provided with check valves 10 on the first parallel bypass passage 9a so as to correspond to the switching valves 17a to 17d, and the pressure oil supplied to the switching valves 17a to 17d. Does not flow backward.
In the following description, the switching valves 17a to 17d are arranged in order from the upstream side (the lower side in FIG. 1), the first switching valve 17a, the second switching valve 17b, the third switching valve 17c, and the fourth switching valve 17d. Will be described.

  Further, the first housing 13a is provided with four cylinder ports 11a, 11b, 11c, and 11d on the side surface other than the mating surface with the second hydraulic control valve group 5b. The cylinder ports 11a to 11d are arranged in order of the first cylinder port 11a, the second cylinder port 11b, the third cylinder port 11c, and the fourth cylinder port 11d from the upstream side.

  The first cylinder port 11a communicates with the bypass passage 12 formed on the upstream side of the first switching valve 17a of the first housing 13a. The second cylinder port 11b communicates with the first switching valve 17a. The third cylinder port 11c communicates with the third switching valve 17c. The fourth cylinder port 11d communicates with the fourth switching valve 17d.

  A cab turning hydraulic motor 2b is connected to the first cylinder port 11a. In addition, one hydraulic motor 2e of the two traveling drive hydraulic motors 2e, 2f is connected to the second cylinder port 11b. Furthermore, an arm driving hydraulic cylinder 2a is connected to the fourth cylinder port 11d. In the present embodiment, the third cylinder port 11c is set as a spare port.

The first housing 13a is provided with three connection ports 11e, 11f, and 11g on the side surface on the mating surface side with the second hydraulic control valve group 5b. The connection ports 11e to 11g are arranged in the order of the first connection port 11e, the second connection port 11f, and the third connection port 11g from the upstream side.
The first connection port 11e communicates with the bypass passage 12a. The second connection port 11f communicates with the second switching valve 17b. The third connection port 11g communicates with the fourth switching valve 17d and the fourth cylinder port 11d.

  Similar to the first housing 13a, the second hydraulic control valve group 5b has a second housing 13b formed in a rectangular parallelepiped shape. In the second housing 13b, four switching valves 27a, 27b, 27c, and 27d are provided so as to be slidable (slidable in the vertical direction in FIG. 2) and substantially in parallel. Each switching valve 27a to 27d is a so-called open center type switching valve. The pressure oil supplied from the second hydraulic pump 4b is supplied to the tank via the second tandem bypass passage 8b formed in the second housing 13b and the second parallel bypass passage 9b branched from the second tandem bypass passage 8b. 7 is connected.

The second housing 13b is provided with a check valve 10 on the second parallel bypass passage 9b so as to correspond to the switching valves 27a to 27d, and the pressure oil supplied to the switching valves 27a to 27d. Does not flow backward.
In the following description, the switching valves 27a to 27d are arranged in order from the upstream side (the lower side in FIG. 1), the first switching valve 27a, the second switching valve 27b, the third switching valve 27c, and the fourth switching valve 27d. Will be described.

Here, the first switching valve 27a is used to drive the hydraulic motor 2b for turning the cab, and the other second switching valve 27b to the fourth switching valve 27d are other hydraulic control valve groups (first hydraulic pressure valve). It is used for auxiliary supply (for merging) for supplying pressure oil to the control valve group 5a and the third hydraulic control valve group 5c).
More specifically, the first switching valve 27a communicates with the first connection port 21a provided on the side surface of the second housing 13b on the mating surface side with the first hydraulic control valve group 5a. The first connection port 21a is connected to the first connection port 11e of the first hydraulic control valve group 5a. Accordingly, the first switching valve 27a of the second hydraulic control valve group 5b is connected to the cab turning hydraulic motor 2b via the bypass passage 12 of the first hydraulic control valve group 5a.

  On the other hand, the second switching valve 27b communicates with the second connection port 21b provided on the side surface of the second housing 13b on the mating surface side with the first hydraulic control valve group 5a. The second connection port 21b is connected to the second connection port 11f of the first hydraulic control valve group 5a. Accordingly, the second switching valve 27b of the second hydraulic control valve group 5b is connected to the second switching valve 17b of the first hydraulic control valve group 5a.

The third switching valve 27c communicates with a fifth connection port 21e provided on the side surface of the second housing 13b on the mating surface side with the third hydraulic control valve group 5c. The fifth connection port 21e is connected to the third hydraulic control valve group 5c.
Further, the fourth switching valve 27d communicates with a third connection port 21c provided on the side surface of the second housing 13b on the mating surface side with the first hydraulic control valve group 5a. The third connection port 21c is connected to the third connection port 11g of the first hydraulic control valve group 5a. As a result, the fourth switching valve 27d of the second hydraulic control valve group 5b is connected to the fourth switching valve 17d of the first hydraulic control valve group 5a.

The second housing 13b is provided with a fourth connection port 21d and a sixth connection port 21f on the side surface on the mating surface side with the third hydraulic control valve group 5c. The fourth connection port 21d communicates with the second switching valve 27b and the second connection port 21b. On the other hand, the sixth connection port 21f communicates with the fourth switching valve 27d and the third connection port 21c.
In addition, a first bypass passage 22a and a second bypass passage 22b are formed in the second housing 13b. The first bypass passage 22a communicates with the parallel bypass passage 9a of the first hydraulic control valve group 5a. On the other hand, the second bypass passage 22b communicates with the tandem bypass passage 8a of the first hydraulic control valve group 5a.

  The third hydraulic control valve group 5c has a rectangular parallelepiped third housing 13c. Within this third housing 13c, five switching valves 37a, 37b, 37c, 37d, 37e for adjusting the flow rate of the pressure oil to each hydraulic actuator 2 are slidable (slidable in the vertical direction in FIG. 2). And provided substantially in parallel. Each switching valve 37a-37e is what is called an open center type switching valve. The pressure oil supplied from the third hydraulic pump 4c passes through the third tandem bypass passage 8c formed in the third housing 13c and the third parallel bypass passage 9c branched from the third tandem bypass passage 8c, 7 is connected.

The third housing 13c is provided with check valves 10 on the third parallel bypass passage 9c so as to correspond to the switching valves 37b to 37e, and the pressure oil supplied to the switching valves 37b to 17e. Does not flow backward.
In the following description, the switching valves 37a to 37e are arranged in order from the upstream side (the lower side in FIG. 1), the first switching valve 37a, the second switching valve 37b, the third switching valve 37c, the fourth switching valve 37d, This will be described as the fifth switching valve 37e.

  Further, the third housing 13c is provided with three cylinder ports 31a, 31b, 31c on the side surface other than the mating surface with the second hydraulic control valve group 5b. The cylinder ports 31a to 31c are arranged in order of the first cylinder port 31a, the second cylinder port 31b, and the third cylinder port 31c from the upstream side.

The first cylinder port 31a communicates with the second switching valve 37b. The second cylinder port 31b communicates with the third switching valve 37c. The third cylinder port 31c communicates with the fourth switching valve 37d.
The other hydraulic motor 2f of the two traveling drive hydraulic motors 2e, 2f is connected to the first cylinder port 31a. In addition, a boom driving hydraulic cylinder 2d is connected to the second cylinder port 31b. Furthermore, a hydraulic cylinder 2c for driving a bucket is connected to the third cylinder port 31c.

  The third housing 13c is provided with a first connection port 31d, a second connection port 31e, and a third connection port 31f on the side surface on the mating surface side with the second hydraulic control valve group 5b. The first connection port 31d communicates with the third switching valve 37c and the second cylinder port 31b. The first connection port 31d is connected to the fourth connection port 21d of the second hydraulic control valve group 5b, and the third switching valve 37c of the third hydraulic control valve group 5c and the second hydraulic control valve group 5b are connected. The second switching valve 27b is connected.

  The second connection port 31e communicates with the fourth switching valve 37d and the third cylinder port 31c. The second connection port 31e is connected to the fifth connection port 21e of the second hydraulic control valve group 5b, and the fourth switching valve 37d of the third hydraulic control valve group 5c and the second hydraulic control valve group 5b. The third switching valve 27c is connected.

  The third connection port 31f communicates with the fifth switching valve 37e. The third connection port 31f is connected to the sixth connection port 21f of the second hydraulic control valve group 5b, and the fifth switching valve 37e of the third hydraulic control valve group 5c and the second hydraulic control valve group 5b are connected. A fourth switching valve 27d is connected.

  On the other hand, the first switching valve 37a of the third hydraulic control valve group 5c is connected to the first bypass passage 22a and the second bypass passage 22b of the second hydraulic control valve group 5b. As a result, the pressure oil flowing into the first switching valve 37a of the third hydraulic control valve group 5c passes through the first bypass passage 22a of the second hydraulic control valve group 5b, and the first parallel of the first hydraulic control valve group 5a. It can supply to the bypass passage 9a.

Here, as shown in detail in FIG. 2, each of the hydraulic control valve groups 5 a to 5 c is arranged in a direction (hereinafter referred to as “the longitudinal direction of the housing”) orthogonal to the direction in which the switching valves 17 a to 37 e are disposed (hereinafter referred to as the longitudinal direction of the housing). (Referred to as the short direction of the housing). The hydraulic control valve groups 5a to 5c are provided so that the switching valves 17a to 37e are arranged in parallel with each other. Cylinder ports 11a to 31f are provided on the side surfaces of the housings 13a to 13c other than the mating surfaces.
Further, the first hydraulic control valve group 5a and the second hydraulic control valve group 5b, and the second hydraulic control valve group 5b and the third hydraulic control valve group 5c are directly connected to the corresponding connection ports 11e to 31f. Yes. Thereby, the hydraulic control valve group 5 as a whole can be reduced in size when the three hydraulic control valve groups 5a to 5c are assembled.

  In addition, each hydraulic pump 4a-4c which supplies pressure oil to each hydraulic control valve group 5a-5c is connected via the pump ports 14a-14c formed in the longitudinal direction end of a housing. Further, in FIG. 2, reference numerals 15a to 15c denote switching valve ports to which pressure oil for driving the switching valves 17a to 37e is supplied.

With such a configuration, when driving one of the two hydraulic motors 2e, 2f for driving the arm and the hydraulic cylinder 2a for driving, the first hydraulic pump 4a is mainly driven. Then, a desired amount of pressure oil is supplied to the hydraulic cylinder 2a and the hydraulic motor 2e via the first hydraulic control valve group 5a.
Further, when the cab turning hydraulic motor 2b is driven, the second hydraulic pump 4b is mainly driven, and the desired hydraulic motor 2b is supplied to the hydraulic motor 2b via the second hydraulic control valve group 5b and the first hydraulic control valve group 5a. Supply pressure oil at flow rate.

Here, the first switching valve 27a of the second hydraulic control valve group 5b to which the cab turning hydraulic motor 2b is connected is one of the four switching valves 27a to 27d provided in the second hydraulic control valve group 5b. It is provided on the most upstream side. For this reason, pressure oil can be supplied to the hydraulic motor 2b for turning the cab while suppressing the pressure loss of the pressure oil discharged from the second hydraulic pump 4b as much as possible.
This will be described in more detail. That is, pressure oil discharged from the second hydraulic pump 4b through the switching valve located on the upstream side or the second parallel bypass passage 9b is supplied to the switching valves (27b to 27d) located on the downstream side. Will be. For this reason, since the pressure loss of this partial pressure oil becomes large, by connecting the hydraulic motor 2b for turning the cab to the first switching valve 27a arranged on the most upstream side, the hydraulic motor 2b is efficiently pressurized. Oil can be supplied.

  The third hydraulic pump 4c is mainly used to drive the hydraulic cylinder 2c for bucket driving, the hydraulic cylinder 2d for boom driving, and the other hydraulic motor 2f of the two hydraulic motors 2e, 2f for driving. And a desired flow rate of pressure oil is supplied to the hydraulic cylinders 2c and 2d and the hydraulic motor 2f via the third hydraulic control valve group 5c.

Here, when driving one of the two hydraulic motors 2e and 2f for driving the arm and the two hydraulic motors 2e and 2f for driving, a request for pressure oil to the hydraulic cylinder 2a and the hydraulic motor 2e is required. The total flow rate may exceed the maximum discharge amount of the first hydraulic pump 4a. In such a case, the pressure oil discharged from the second hydraulic pump 4b and the third hydraulic pump 4c is supplied to the first hydraulic control valve group 5a via the second hydraulic control valve group 5b.
That is, the second switching valve 27b to the fourth switching valve 27d of the second hydraulic control valve group 5b are communicated with the first hydraulic control valve group 5a and the third hydraulic control valve group 5c, respectively. For this reason, it becomes possible to supply the pressure oil discharged from the 2nd hydraulic pump 4b and the 3rd hydraulic pump 4c to the 1st hydraulic control valve group 5a as needed. Thereby, the pressure oil of a desired flow rate can be reliably supplied to the hydraulic cylinder 2a and the hydraulic motor 2e.

Also, when driving the hydraulic cylinder 2c for driving the bucket, the hydraulic cylinder 2d for driving the boom, and the other hydraulic motor 2f of the two hydraulic motors 2e, 2f for driving, the arm driving hydraulic cylinder is also used. The same operation as that for driving the hydraulic motor 2e for driving 2a or traveling is performed.
That is, when driving the hydraulic cylinder 2c for driving the bucket, the hydraulic cylinder 2d for driving the boom, and the other hydraulic motor 2f for driving, the required flow rate of pressure oil to the hydraulic cylinders 2d and 2f and the hydraulic motor 2f If the sum of the pressures exceeds the maximum discharge amount of the third hydraulic pump 4c, the pressure oil discharged from the first hydraulic pump 4a and the second hydraulic pump 4b is transferred to the third hydraulic control via the second hydraulic control valve group 5b. It is supplied to the valve group 5c.

Therefore, according to the above-described embodiment, the first switching valve 27a of the second hydraulic control valve group 5b among the three hydraulic control valve groups 5a to 5c is configured to drive the hydraulic motor 2b for turning the cab. Therefore, the operability of the hydraulic motor 2b for turning the cab that is frequently used can be improved. In other words, even when other hydraulic actuators 2 other than the hydraulic motor 2b are operated at the same time, insufficient supply of pressure oil to the hydraulic motor 2b can be prevented, and the operability of the hydraulic motor 2b can be ensured. It can be improved.
Further, by specializing the second hydraulic pump 4b as a hydraulic pump that drives the hydraulic motor 2b for turning the cab, the size of the second hydraulic pump 4b is reduced as compared with the other hydraulic pumps 4a and 4c. It is also possible to do.

  Further, the switching valves other than the first switching valve 27a of the second hydraulic control valve group 5b, that is, the second switching valve 27b to the fourth switching valve 27d are connected to other hydraulic control valve groups (the first hydraulic control valve group 5a and The third hydraulic control valve group 5c) is configured as an auxiliary supply (for merging) for supplying pressure oil. For this reason, the pressure oil discharged from the three hydraulic pumps 4a to 4c can be supplied to each hydraulic actuator 2 via the second hydraulic control valve group 5b, respectively, as necessary. Therefore, the operability of a construction machine (for example, a hydraulic excavator) on which the hydraulic drive device 1 is mounted can be further improved.

  Further, the second hydraulic control valve group 5b configured for driving and auxiliary supply of the hydraulic motor 2b for turning the cab is disposed between the first hydraulic control valve group 5a and the third hydraulic control valve group 5c. Yes. The first hydraulic control valve group 5a and the second hydraulic control valve group 5b, and the second hydraulic control valve group 5b and the third hydraulic control valve group 5c are connected directly to the corresponding connection ports 11e to 31e. Yes. For this reason, it is possible to store all the auxiliary supply flow paths (pressure oil merging flow paths) of pressure oil from the hydraulic pumps 4a to 4c to the hydraulic actuators 2 in the housings 13a to 13c. Accordingly, it is not necessary to provide an auxiliary supply flow path, the manufacturing cost of the hydraulic drive device 1 can be reduced, and the entire hydraulic control valve group 5 can be reduced in size.

  In addition, the hydraulic control valve groups 5a to 5c are provided so that the switching valves 17a to 37e are arranged in parallel to each other. Therefore, the space occupied by the entire hydraulic control valve group 5 when the three hydraulic control valve groups 5a to 5c are assembled can be saved. Therefore, the layout of the hydraulic drive device 1 at the time of design becomes easy.

  Further, the first switching valve 27a of the second hydraulic control valve group 5b to which the cab turning hydraulic motor 2b is connected is, among the four switching valves 27a to 27d provided in the second hydraulic control valve group 5b. It is provided on the most upstream side. For this reason, pressure oil can be supplied to the hydraulic motor 2b for turning the cab while suppressing the pressure loss of the pressure oil discharged from the second hydraulic pump 4b as much as possible. For this reason, the operativity of the hydraulic motor 2b can further be improved.

  In the above-described embodiment, the hydraulic drive device 1 includes the three hydraulic pumps 4 (the first hydraulic pump 4a, the second hydraulic pump 4b, and the third hydraulic pump 4c), and the hydraulic pumps 4a and 4b. , 4c, the case where the three hydraulic control valve groups 5 (the first hydraulic control valve group 5a, the second hydraulic control valve group 5b, and the third hydraulic control valve group 5c) are provided has been described. However, the present invention is not limited to this, and the hydraulic drive device 1 may include three or more hydraulic pumps 4 and hydraulic control valve groups 5. In this case, one of the plurality of hydraulic control valve groups 5 is set to drive the cab turning hydraulic motor 2b (second hydraulic control valve group 5b). In this case, it is desirable that the drive hydraulic control valve group of the hydraulic motor 2b for turning the cab is disposed between the other hydraulic control valve groups, and the respective hydraulic control valve groups are provided in an overlapping manner.

  Further, the number of switching valves 17a to 37e provided in each of the hydraulic control valve groups 5a to 5c is not limited to the number of the above-described embodiments, and the number of switching valves is arbitrarily set as necessary. It is possible. In particular, the second hydraulic control valve group 5b only needs to be provided with the first switching valve 27a connected to at least the hydraulic motor 2b for turning the cab.

Furthermore, in the above-described embodiment, the case where the four switching valves 27a to 27d are provided in the second hydraulic control valve group 5b has been described. However, the present invention is not limited to this. Between the first switching valve 27a and the second switching valve 27b, the second tandem bypass passage 8b between the first switching valve 27a and the second switching valve 27b and the second switching valve 27b. A switching valve 27e (indicated by a two-dot chain line in FIG. 1) that can shut off the two parallel bypass passages 9b may be provided.
By providing this switching valve 27e, it is possible to efficiently supply all the pressure oil discharged from the second hydraulic pump 4b to the hydraulic motor 2b for turning the cab. For this reason, the operability of the cab can be stabilized even when the frequency of the cab turning drive is extremely high.

  In the above-described embodiment, the first hydraulic control valve group 5a includes one of the hydraulic cylinder 2a for driving the arm, the hydraulic motor 2b for turning the cab, and the two hydraulic motors 2e and 2f for driving the travel. The case where the hydraulic motor 2e is connected has been described. Further, the third hydraulic control valve group 5c is connected to the hydraulic cylinder 2c for bucket driving, the hydraulic cylinder 2d for boom driving, and the other hydraulic motor 2f of the two hydraulic motors 2e and 2f for driving driving. Explained the case. However, the present invention is not limited to these, and various hydraulic actuators 2 other than the cab turning hydraulic motor 2b can be connected to the first hydraulic control valve group 5a and the third hydraulic control valve group 5c. .

According to at least one embodiment described above, of the three hydraulic control valve groups 5a to 5c, the first switching valve 27a of the second hydraulic control valve group 5b is used for driving the hydraulic motor 2b for turning the cab. Since it comprises, the operativity of the hydraulic motor 2b for cab turning with a high use frequency can be improved. In other words, even when other hydraulic actuators 2 other than the hydraulic motor 2b are operated at the same time, insufficient supply of pressure oil to the hydraulic motor 2b can be prevented, and the operability of the hydraulic motor 2b can be ensured. It can be improved.
Further, by specializing the second hydraulic pump 4b as a hydraulic pump that drives the hydraulic motor 2b for turning the cab, the size of the second hydraulic pump 4b is reduced as compared with the other hydraulic pumps 4a and 4c. It is also possible to do.

  Further, the switching valves other than the first switching valve 27a of the second hydraulic control valve group 5b, that is, the second switching valve 27b to the fourth switching valve 27d are connected to other hydraulic control valve groups (the first hydraulic control valve group 5a and The third hydraulic control valve group 5c) is configured as an auxiliary supply (for merging) for supplying pressure oil. For this reason, the pressure oil discharged from the three hydraulic pumps 4a to 4c can be supplied to each hydraulic actuator 2 via the second hydraulic control valve group 5b, respectively, as necessary. Therefore, the operability of a construction machine (for example, a hydraulic excavator) on which the hydraulic drive device 1 is mounted can be further improved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Hydraulic drive device, 2 ... Hydraulic actuator, 4 ... Hydraulic pump, 4a ... 1st hydraulic pump (hydraulic pump), 4b ... 2nd hydraulic pump (hydraulic pump), 4c ... 3rd hydraulic pump (hydraulic pump), 5 ... hydraulic control valve group, 5a ... first hydraulic control valve group (hydraulic control valve group), 5b ... second hydraulic control valve group (hydraulic control valve group), 5c ... third hydraulic control valve group (hydraulic control valve group) , 8a ... first tandem bypass passage, 8b ... second tandem bypass passage (pressure oil passage), 8c ... third tandem bypass passage, 9a ... first parallel bypass passage, 9b ... second parallel bypass passage (pressure oil) ), 9c, third parallel bypass passage, 11a, 31a, first cylinder port, 11b, 31b, second cylinder port, 11c, 31c, third cylinder port, 11d, fourth cylinder port, 11e. 21a, 31d ... 1st connection port (connection port), 11f, 21b, 31e ... 2nd connection port (connection port), 11g, 21c, 31f ... 3rd connection port (connection port), 17a, 27a, 37a ... 1st 1 switching valve (switching valve), 17b, 27b, 37b ... 2nd switching valve (switching valve), 17c, 27c, 37c ... 3rd switching valve (switching valve), 17d, 27d, 37d ... 4th switching valve (switching) Valve), 37e ... fifth switching valve (switching valve), 21d ... fourth connection port (connection port), 21e ... fifth connection port (connection port), 21f ... sixth connection port (connection port)

Claims (5)

At least three hydraulic pumps for discharging pressure oil;
At least three hydraulic pumps corresponding to the number of the hydraulic pumps are provided, the flow rate of the hydraulic oil discharged from the hydraulic pumps is controlled, and the hydraulic oil is supplied to hydraulic actuators of construction machines including a turning function. A control valve group,
Each of the plurality of hydraulic control valve groups has at least one switching valve to which the hydraulic actuator is connected,
One of the plurality of hydraulic control valve groups is configured for turning driving in which one switching valve is connected to the hydraulic actuator for turning driving of the construction machine, and the switching valve other than for turning driving is used. Is a hydraulic drive device configured for auxiliary supply for supplying pressure oil to the other hydraulic control valve group. The plurality of hydraulic control valve groups are provided in an overlapping manner so that the respective connection ports communicate directly with each other,
2. The hydraulic drive device according to claim 1, wherein the hydraulic control valve group having the switching valve for turning driving is disposed between the other hydraulic control valve groups.   The hydraulic drive device according to claim 2, wherein the plurality of hydraulic control valve groups are provided so as to overlap each other so that the switching valves are arranged in parallel to each other. The hydraulic control valve group having the switching valve for turning driving has a plurality of the switching valves,
The hydraulic drive according to any one of claims 1 to 3, wherein the switching valve for turning driving is disposed on the most upstream side of the flow path of the pressure oil among the plurality of switching valves. apparatus.   5. The hydraulic drive device according to claim 4, wherein a switching valve capable of shutting off the flow path of the pressure oil is provided between the switching valve for driving for turning and the other switching valve.

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