JPH0235123A - Hydraulic curcuit for pilot operated type hydraulic shovel - Google Patents

Abstract

PURPOSE:To make it possible to select operating methods of at least three specific companies by installing directional selector valves on pilot pipings witch connect each pilot valve and the pilot operating part of main directional selector valves. CONSTITUTION:Directional selector valves 24, 25,...32 are installed on pilot pipings 23A, 23B,...23H which connect eight pilot valves 21A, 21B, ...21H operated by two operating levers, making four valves one set, and pilot operating parts 22a, 22b,...22h of main directional selector valves operating each actuator. As for these directional selector valves 24, 25,...32, the directional selector valve 24 by way of example, directly connects pipings 23B and 23G at a non- changing over position (a), and at a changing over position (b) connects pipings 23B and 23G by replacing their inflow and outflow sides. Therefore, the operating method of operating levers can be changed over to three types by selectively changing over the directional selector valves 24, 25,...32 as the occasion may demand.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic circuit for a pilot-operated hydraulic excavator, in which the operating method of the operating lever can be made common among different types of excavators that have different operating methods for operating the operating lever.

In general, a hydraulic excavator has an engine control lever in the driver's cab that controls the starting rotation speed of the engine, two drive control levers that control the left and right drive motors, and control the actuator of the work equipment. There are five operating levers including two working operating levers, each of which is configured to operate a plurality of actuators (usually 2 (Ii!1)).

Therefore, among the operating methods of each operation lever of hydraulic excavators using the conventional technology of at least three companies, three representative
The operating method of the company will be explained with reference to FIGS. 1 to 5.

Fig. 1 is an overall configuration diagram of a hydraulic excavator to which the conventional technology is applied, Fig. 2 is an explanatory diagram showing the operating direction of each operation lever, and Fig. 3 is an illustration showing the operating direction of the operating lever according to Company X's specifications and each Figure 4 is an explanatory diagram showing the relationship between the actuators, Figure 4 is an explanatory diagram showing the relationship between the operation direction of the operating lever and each actuator according to the specifications of company Y, and Figure 5 is the same (the relationship between the operation direction and each actuator according to the specifications of the two companies). FIG.

In FIG. 1, 1 is an undercarriage, and 2 is the undercarriage 1.
A revolving upper structure 3 is a working device provided on the revolving upper structure 2 and has an operator's cab 2A. Here, the working device 3 is composed of a boom 4, an arm 5, a packet 6, etc., which are operated by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9. Reference numeral 10 indicates a turning motor for turning the upper revolving structure, and reference numeral 11.12 indicates a working operating lever provided in the operator's cab 2A, one operating lever 11 having operating directions A, B, C, and D. , the other operating lever 12 has operating directions E, F, G, H. In addition, in the following explanation, the dump operation of arm 5 is referred to as a, the cloud operation is referred to as b,
C1 is a left-turning movement of the turning motor 10; d is a turning right-hand movement of the turning motor 10; e is the raising movement of the boom 4; f is the lowering movement of the boom 4; g is the clouding movement of the packet 6;

However, as shown in Figure 3, Company X's operating lever 11.1
The relationship between the operating directions A-H of 2 and each cylinder 7°8.9 and the swing motor 10 is that the six directions are arm dump a, B.
The direction is arm cloud b, the C direction is turning pressure c, the D direction is turning cloth d, the E direction is boom up e, the F direction is boom down f, the C direction is packet cloud g, and the H direction is packet dump h. It is designed to make you do this.

On the other hand, as shown in FIG. 4, the operation lever 11 of company Y.
The relationship between the 12 operating directions A-H, each cylinder 7, 8, 9, and the swing motor 10 is that the 6 directions are bucket dump h.
, B direction is packet cloud g, C direction is boom up e
, D direction is boom lowering f, E direction is arm dump a, F
The direction is arm cloud b, the G direction is turning left c, and the H direction is turning cloth d.

Furthermore, as shown in FIG. 5, the operating lever 11.1 of the two companies
The relationship between the operating direction ANH of 2, each cylinder 7° 8.9, and the swing motor 10 is that for only the operating lever 11, direction A is swing left c, direction B is swing cloth d, and direction C is arm cloud b, D. The direction is arm dump a, and the operating direction of the operating lever 12 is the same as that of Company X shown in FIG.

In this way, each hydraulic excavator has its own operating lever 11.
．． The relationship between the operating direction ANH of the cylinders 7, 8, 9 and the operating direction of the swing motor 10 is different. For this reason, an operator who is accustomed to the operating method of a hydraulic excavator of one company may find it difficult to operate the operating method of another company's hydraulic excavators because he or she is unfamiliar with it, and it is also dangerous. Therefore, in the case of hydraulic excavators according to the prior art, the actual situation is that the company's operating system is purposely improved to the operating system of other companies in response to the user's request, and then supplied to the user. However, even if you improve your company's operating method, it will be very difficult to operate a single hydraulic excavator when multiple operators who are accustomed to different operating methods, or when a leasing company lends the excavator to an unspecified person. The disadvantage is that it is inconvenient.

The present invention was devised in view of the problems and drawbacks of the prior art described above, and it is possible to freely switch the operating method of the operating lever for at least three companies out of the operating methods that differ for each company. The object of the present invention is to provide a hydraulic circuit for a pilot-operated hydraulic excavator.

In order to achieve the above object, the configuration adopted by the present invention is as follows:
The hydraulic excavator has four work actuators, each consisting of a boom cylinder, an arm cylinder, a bucket cylinder, and a swing motor, and two pilot operating units for each work actuator to switch the driving direction of each work actuator. 4 pilot type main directional switching valves, 8 pilot valves each supplying pilot pressure to the pilot operation part of the lichen directional switching valve, and 4 pilot valves each according to the operating direction as a set. In a hydraulic circuit for a hydraulic excavator of a pilot operation type, the hydraulic circuit includes two operation levers that are operated as a hydraulic excavator, and pilot piping that connects each of the pilot valves and a pilot operation part of each main directional switching valve, respectively. A directional control valve is provided in the middle of the control valve, which changes the operation method of each of the control levers of at least three companies by switching the connection between each of the pilot valves and the pilot operating part of each main directional control valve. It is characterized by

By providing the directional switching valve configured as described above in the middle of the pilot piping, 4
If the connection relationship of each pilot piping between the pilot valves that are operated as a set and the pilot operating section of each main directional switching valve is changed appropriately, it will be possible to adapt to the operating method of the operating lever of at least three companies. , the operator can freely select the operating method of the company he or she is familiar with, and improves workability and safety when controlling multiple actuators that make up a hydraulic excavator with two operating levers.

Hereinafter, embodiments of the present invention will be specifically described based on FIGS. 6 to 9, taking as an example a case where the operation methods of three companies can be changed simultaneously. Note that the same components as those in the prior art described above are given the same reference numerals, and their explanations will be omitted.

First, FIG. 6 shows a hydraulic circuit principle diagram when the operating method of company X shown in FIG. 3 and the operating method of company Y shown in FIG. 4 are mutually changed.

In FIG. 6, 21A, 21B, ... 21H are pilot valves 2 operated by operating levers 11.12.
2a, 22b, ... 22h are pilot operation parts of the main directional switching valves that operate each actuator, 23A,
23B, . . . 23H are pilot pipes connecting these, and 24, 25, 26°, 27.28, 29.30 are directional valves, respectively. Here, the directional switching valve 24 is provided between the pilot pipes 23B and 23G, and the directional switching valve 25 is provided between the pilot pipes 23A and 23H.
The directional switching valve 26 is provided between the pilot pipes 23C and 23B, and the directional switching valve 27 is provided between the pilot pipes 23C and 23B.
The directional switching valve 28 is provided between the pilot pipe 23
A directional switching valve 29 is provided between the pilot pipes 23A and 23B, and a directional switching valve 3 is provided between the pilot pipes 23A and 23B.
0 is provided between pilot pipes 23B and 23G. Further, each of the directional switching valves 24 to 30, for example, the directional switching valve 2
For example, as shown in Fig. 7, 4 is a 2-position, 4-boat electromagnetic directional switching valve, in which the pilot pipes 23B and 23G are directly connected when in the non-switching position (a), and when switched to the switching position (b). Pilot pipe 23B inflow side and 2
3G outflow side and between the pilot pipe 23G inflow side and 23B outflow side. The same applies to the other directional control valves 25 to 30.

In addition, in FIG. 6, the pilot valve 21A.

The European letters A, B,...H in 21B,...21H indicate pilot valves that can be switched by operating the operating levers 11.12 in the operating directions A, B,...H, and the pilot operating portions. The subscripts a, b, ...h of 22a, 22b, ...22h are also arm dump a, arm cloud b
, . . . indicates the pilot operating portion of each main directional switching valve used for the packet dump h, etc., and corresponding subscripts are used for these.

Thus, by setting each directional control valve 24 to 30 to the non-switching position (a) shown in FIG. 7, each pilot valve 21A
, 21B, . . . 21H are the pilot operation parts 22a,
22b, . . . 22h, and the operation method is according to the specifications of Company X shown in FIG. As a result, by operating the operating lever 11 in the inward direction, the pilot valve 21A is actuated, and the pressure oil from the pilot pump (not shown) operates the arm cylinder 8 in the dumping direction via the pilot piping 23A. It is supplied to the pilot operation part 22a of the main directional switching valve to operate the arm 4 in the arm dump a direction. In addition, by operating the operating lever 11 in the direction B, the pilot valve 21B is operated, and the pressure oil from the pilot pump is transferred to the pilot pipe 23.
B is supplied to the pilot operating portion 22b of the main directional switching valve which is to operate the arm cylinder 8 in the cloud direction, and causes the arm 4 to operate in the arm cloud direction b. The same applies to the following.

On the other hand, when each of the directional control valves 24 to 30 is switched to the switching position (b) shown in FIG. 7, the operation method according to the specifications of Company Y shown in FIG. 4 is achieved via the directional control valves 24 to 30. That is, 2
1A → 24 → 23G → 22g, 21B → 24 → 23G,
21C→23G-26--23D-28-23E-22
e, 21D → 23D → 26 → 23C → 27 → 23F → 2
2f, 21E → 23E → 28 → 23D → 29 → 23A-
=22a, 21F-23F-27-23C-430→2
3B→22b, 21G→23G→24→23B→30→
23C → 22C5 further 21H-23H → 25 → 23A
→ 29 → 23D → 22d, and the connection relationship is the same as that shown in FIG. 4.

Next, Fig. 8 shows a hydraulic circuit principle diagram in which the operating methods of the two companies can be changed mutually, in addition to the case where the operating methods of Company X and Company Y shown in Fig. 6 are mutually changed. be.

That is, in FIG. 8, the same components as in FIG. 6 are given the same reference numerals, and in this case, in addition to the hydraulic circuit in FIG. 6, a directional control valve 31 is installed between the pilot pipes 23B and 23C. In addition to providing pilot piping 23C, 23D
A directional switching valve may be provided between them.

With the hydraulic circuit configured in this way, Company
To change to the operating method of directional control valves 24 to 28.
30 is held in the non-switching position (a), and the directional switching valves 29, 3 are
1. Switch only 32 to the switching position (b). As a result, 21A → 23A-29-23D-32-23C-22
c, 21B → 23B → 31 → 23C → 32 → 23D → 2
2d, 21C-31→23B→22b, 23D→29→
23A to 22d, respectively, and have the same connection relationship as in FIG.

In addition, when changing Company X's operation method to Company 2's operation method,
Instead of switching the directional control valves 29, 31.32, the directional control valves 29., 30.32 may be used, and in the case of such a circuit configuration, the directional control valve 31 can be omitted.

(Then, the operating method of company X or company Y is
To change to the formula, leave the directional control valves 24 to 28.30 in the non-switching position (a),
This can be done by switching to the switching position (b).

In this case, in order to use the operation method of Company X, the directional control valve 24
A switch mechanism that holds the front part of ~32 in the non-switching position (A), and a directional control valve 24~3 to use the operation method of Company Y.
0 to the switching position (b), and a switch mechanism to switch the directional control valves 29, 31, 32 to the switching position (b) in order to use the two companies' operation method. The operation method can be instantaneously changed by pressing three changeover switches provided in the operator's cab 2A of the upper revolving structure 2 in FIG.

Note that although the operation methods of each company are exemplified by three companies, if the application is to be applied to a hydraulic excavator from a company with a different operation method, a directional control valve may be added or the existing directional control valve 24 may be used.
- 32 may be used to change the connection relationship of the pilot pipes 23A to 23H.

Next, Figure 9 shows a concrete hydraulic circuit that allows the operating methods of Company X, Company Y, and the two companies to be mutually changed. The operation of the motor 10 will be specifically described. Note that the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted.

However, 41, 42, 43.44 are the left and right switching positions (
The figure shows a 3-position, 6-boat main directional switching valve having a), (b) and a neutral position (c). A pilot operating section 41g that operates on the bucket dump h side, and a pilot operating section 41h that operates on the bucket dump h side.
and has. The main direction switching valve 42 operates the boom 7, and includes a pilot operating section 42e for operating the boom 7 toward the boom-up e side and a pilot operating section 42f for operating the boom toward the boom-down f side. Main direction switching valve 43
actuates the arm 8, and includes a pilot operating section 43a that operates the arm 8 toward the arm dump a side, and a pilot operating section 43b that operates the arm 8 toward the arm cloud b side.
and has. Furthermore, the main direction switching valve 44 is connected to the swing motor 1.
0, and the pilot operation part 4 for swirl pressure C
4c, and a pilot operating section 44d for the swirling cloth d. 45 is a pump, 46 is a tank, 47 is a supply pipe that supplies pressure oil from the pump 45, 48 is a return pipe,
Each of the main directional switching valves 41 to 44 forms a tandem circuit with respect to the supply pipe 47.

49.50 indicates a pilot valve device operated by the operating lever 11.12, one pilot valve device 49
are pilot valves 49A and 49B.

49G and 49D, and the other pilot valve device 50 has pilot valves 50E, 50F, and 50G.

It has 50H.

Reference numerals 51, 52, 53, 54, and 55.56 indicate directional switching valves, and directional switching valves 51, 52. The directional control valves 54, 55, and 56 are two-position, four-boat electromagnetic directional control valves having a non-switching position (a) and a switching position (b).

On the other hand, 57A, 57B, 57G, 57D.

57E, 57F, 57G, and 57H indicate pilot pipes, and one end of each pilot pipe 57A to 57H is connected to a pilot valve 49A to 49D of each pilot valve device 49.50.
, 50E to 50H, and the other pilot pipe 57
A, 57B.

The other ends of 57G and 57H are connected to the inflow side of the directional switching valve 51, and are pilot pipes 57C and 57D.

The other ends 57E and 57F are connected to the inflow side of the directional switching valve 52.

58A, 58B, 58G, 58D, 58E.

58F, 58G, and 58H also indicate pilot piping, and one end of the pilot piping 58A, 58B is connected to the outflow side of the directional control valve 51, and the pilot piping 58C, 58D
One end is connected to the outflow side of the directional switching valve 52, and the other end thereof is connected to the inflow side of the directional switching valve 53. One end of the pilot pipes 58E, 58F is connected to the outflow side of the directional switching valve 52, and the other end thereof is connected to each pilot operating section 42e, 42f of the main directional switching valve 42 for the boom. One ends of the pilot pipes 58G and 58H are connected to the outflow side of the directional switching valve 51, and the other ends thereof are connected to the inflow side of the directional switching valve 54.

Also, 59A, 59B, 59C, 59D.

59G and 59H also show pilot piping, one end of the pilot piping 59A, 59B, 59C, 59D is connected to the outflow side of the directional switching valve 53, and the other pilot piping 59A,
The other end of 59B is connected to the inflow side of directional switching valve 55, and the other ends of pilot pipes 59C and 59D are connected to the inflow side of directional switching valve 56, respectively. Pilot piping 59G, 59
One end of H is connected to the outflow side of the directional switching valve 54, and the other end thereof is connected to each pilot operation section 41g, 41h of the main directional switching valve 41 for packet.

Furthermore, 60A, 60'B, 60G, and 60D also show pilot piping, and pilot piping 60A.

One end of 60B is connected to the outflow side of the directional switching valve 55, and the other end thereof is connected to each pilot operation section 43a, 43b of the main directional switching valve 43 for arm. Further, one end of the pilot pipes 60C, 60D is connected to the outflow side of the directional switching valve 56, and the other end thereof is connected to each pilot operation part 44c, 44d of the main directional switching valve 44 for the swing motor.

In addition, in Fig. 9, each main directional control valve 43, 44° 42.4
1 each pilot operating section 43a.

43b, 44c, 44d, 42e, 42f.

The subscripts a, b, -h of 41g and 41h are arm dump a, arm cloud b, ... bucket dump h in Fig. 1.
The corresponding subscript is used. In addition, each pilot valve 49A to 49D, 50E to 49 of the pilot valve device 49.50
50H, pilot piping 57A-57H, 58A-58
H, 59A-59D, 59G, 59H, 60A-60D
The European letters A, B, . . . H correspond to the operating directions A, B, . . . H of the operating lever 11.12.

The present embodiment is configured as described above, and its operation will be described below.

First, in order to use the operation method according to the specifications of Company X, all of the directional control valves 51 to 56 are set to the non-switching position (a), so that the circuit configuration is brought to the state shown in FIG. 9. As a result, for example, by operating the operating lever 11 in the A direction, the pilot valve 49A of the pilot valve device 49 is activated, and 57A→51→58A→53→59A→55→60
A→43a is connected. As a result, the arm main direction switching valve 43 is switched to the switching position (b), and the pump 45
The pressure oil is supplied in the direction of contracting the arm cylinder 8, and moves the arm 5 toward the arm dump a side. Hereinafter, even if the operation levers 11 and 12 are operated in the other direction B-H, the operation can be similarly performed according to the specifications of Company X shown in FIG. 3.

Next, in order to change the circuit configuration from the one according to the specifications of company X to the one according to the specifications of company Y, each directional valve 51
- 56 solenoids are energized all at once, and the switching position (b) is reached.
And it is sufficient. As a result, for example, by operating the pilot valve 49A of the pilot valve device 49 with the operating lever 11, 57A→51→58G→54→59H→
41h is connected. As a result, the packet main direction switching valve 41 becomes the switching position (b), and pressure oil from the pump 45 is supplied in the direction of contracting the packet cylinder 9.
Packet 6 is activated to the bucket dump h side. Hereinafter, when the operating levers 11 and 12 are operated in other directions B to H, the operation can be similarly performed according to the specifications of Company Y shown in FIG. 4.

Furthermore, in order to change from the operating method according to the specifications of Company X or Company Y to the operating method of Seven Companies, it is only necessary to switch only the directional control valves 53 and 56 to the switching position (B). As a result, by operating the pilot valve 49A of the pilot valve device 49 using the operating lever 11, for example, the 57A→51→5
8A→53→59D→56→60C→44c are connected. Thereby, the main direction switching valve 44 for the swing motor becomes the switching position (A), and the swing motor 10 can be turned to the left C side of the swing. Similarly, when the operation lever 11 is operated in directions B, C, and D, the operation can be performed according to the specifications of the seven companies shown in FIG. Note that when the operating lever 12 is operated in the E, F, G, and H directions, there is no difference from the specifications of Company X.

In addition, in the example, the hydraulic circuit for a pilot-operated hydraulic excavator to which the present invention is applied is exemplified in which the operating method is changed simultaneously for three companies, Company X, Company Y, and Company 7, but if Of course, the present invention may be applied to the operating methods of many companies.

Furthermore, in the embodiment, an electromagnetic directional valve is used as the directional valve, but a hydraulic directional valve or a pneumatic directional valve may also be used.

Further, the number of directional switching valves, switching mode, etc. can be selected as appropriate, and are not limited to those of the embodiment, as long as valve switching as illustrated in FIG. 6 or 8 can be realized.

The hydraulic circuit for a pilot-operated hydraulic excavator according to the present invention is as described above in detail, and includes each pilot valve operated by the operating lever and the pilot operating section of the main directional switching valve that operates each work actuator. A directional switching valve is installed in the piping that connects between the pipes 1 and 1 to switch the operating method of each company, and by operating the directional switching valve, each company can switch between the operating methods of the operating lever of at least three companies. Since the pilot piping connection direction can be changed to change the operating method for each hydraulic excavator, operators can easily change the operating method of hydraulic excavators from at least three manufacturers to the operating method of the company they are familiar with, thereby improving safety. can be increased. In addition, there is no need to change the pilot piping connection and supply it to the user in order to improve the company's operating method to another company's operating method based on the user's request, as is the case with conventional technology. Productivity can be increased. Furthermore, it is extremely convenient for leasing companies and the like who lend hydraulic excavators to unspecified parties, as they can freely change the operating method for any company's hydraulic excavators.

[Brief explanation of the drawing]

Figures 1 to 5 relate to the prior art; Figure 1 is an overall configuration diagram of a hydraulic excavator to which a pilot-operated hydraulic circuit according to the prior art is applied; Figure 2 shows the operating direction of the work operating lever. 3 is an explanatory diagram showing the relationship between the operating direction of the operating lever and each actuator according to Company X's specifications, and FIG. 4 is an explanatory diagram showing the relationship between the operating direction of the operating lever and each actuator according to Company Y's specifications. , Fig. 5 is an explanatory diagram showing the relationship between the operating direction and each actuator based on the specifications of the two companies, and Fig. 6 is the operating method of company X shown in Fig. 3 and the operating method of company Y shown in Fig. 4. Fig. 7 is a circuit diagram showing specific examples of each directional valve in Fig. 6, and Fig. 8 shows the operation of Company X and Company Y shown in Fig. 6. In addition to mutually changing the methods, the hydraulic circuit principle diagram shows that the operating methods of the two companies can be changed mutually. Figure 9 shows a concrete example of how the operating methods of Company X, Company Y, and the two companies can be changed mutually. The hydraulic circuit diagram is shown below. DESCRIPTION OF SYMBOLS 1... Lower traveling body, 2... Upper rotating body, 3... Working device, 4... Boom, 5... Arm, 6... Packet, 7... Boom sill, 8... ...Arm cylinder, 9...Bucket cylinder, 10...Swivel motor, 11.12...Work operation lever, 2LA, 21
B, 21C. 21D, 21E, 21F, 21G, 21H... Pilot valves, 22a, 22b, 22c, 22d. 22e, 22f, 22g, 22h--pilot operation section, 23A, 23B, 23C, 23D. 23E, 23F, 23G, 23H... Pilot piping, 24, 25. '26,27,28,29゜30.31
．． 32... Directional switching valve, 41,4243.44-...
Main directional valve, 43a, 43b. 44c, 44d, 42e, 42f, 41g. 41h...Pilot operation unit, 49.50...Pilot valve device, 49A, 49B, 49G, 49D. 49E, 49F, 49G, 49H...pilot valve,
51, 52, 53, 54, 55° switching valve, 57A, 57B, 57C. 57E, 57F, 57G, 57H. 58B, 58C, 58D, 58E. 58G, 58H, 59A, 59B. 59D, 59G, 59H, 60A. 60C, 60D...Pilot piping. 56...Direction 57D. 58A. 58 F. 59 C9 60B.

Claims (1)

[Claims] The hydraulic excavator has four work actuators, each consisting of a boom cylinder, an arm cylinder, a bucket cylinder, and a swing motor, and two pilot operating units for each work actuator to switch the driving direction of each work actuator. A set of four pilot type main directional switching valves, eight pilot valves that supply pilot pressure to the pilot operating portion of each main directional switching valve, and four of each pilot valve depending on the operating direction. In a hydraulic circuit for a hydraulic excavator of a pilot operation type, the hydraulic circuit includes two operation levers that are operated as a hydraulic excavator, and pilot piping that connects each of the pilot valves and a pilot operation part of each main directional switching valve, respectively. A directional control valve is provided in the middle of the control valve, which changes the operation method of each of the control levers of at least three companies by switching the connection between each of the pilot valves and the pilot operating part of each main directional control valve. A hydraulic circuit for a pilot-operated hydraulic excavator featuring: