Excavator hydraulic system and excavator

Abstract

The present invention discloses an excavator hydraulic system and an excavator. Hydraulic oil output by a variable displacement pump enters a boom link and a boom link through the P port of a main valve. The boom link is used to drive the boom cylinder and includes a boom valve core. The boom valve core's inlet is connected to the P port of the main valve. A working oil port 1 of the boom valve core is connected to the small chamber of the boom cylinder and the inlet of the first boom relief valve, while a working oil port 2 is connected to the large chamber of the boom cylinder and the inlet of the second boom relief valve. The outlets of the first boom relief valve and the second boom relief valve are respectively connected to the oil return port of the main valve. The compensating oil port of the boom valve core is connected to the inlet of a boom compensator. The control oil port 1 of the boom compensator is connected to the Ls port of the main valve. The control oil port 2 is connected to the oil return port of the main valve in sequence through a two-position, two-way solenoid valve and a stabilizing relief valve. The stabilizing relief valve is used to maintain the excavator operating within a set operating limit. The present invention enables the excavator to operate stably according to the set load, avoiding the problem of overall machine instability.

Description

Technical Field

[0001] The present invention belongs to the technical field of excavators, and in particular relates to an excavator hydraulic system and an excavator. Background Art

[0002] Excavators exported from Europe, the US, and Australia are generally short-tail or tailless models. Standard equipment generally does not affect overall machine stability. However, these markets often feature quick-change and heavy-duty tools, which can lead to instability. Existing excavators lack restrictions or necessary warnings in this regard, leading users to believe that overall machine performance is compromised. Summary of the Invention

[0003] In order to solve the deficiencies in the prior art, the present invention provides an excavator hydraulic system and an excavator, which can enable the excavator to work stably according to a set load and avoid the problem of instability of the entire machine.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] In the first aspect, a hydraulic system for an excavator is provided, comprising a variable pump, wherein the hydraulic oil output by the variable pump enters the P port of the main valve, and enters the boom link and the arm link respectively through the P port of the main valve; the boom link is used to drive the boom cylinder, comprising a boom valve core, the inlet of the boom valve core is connected to the P port of the main valve, the working oil port 1 of the boom valve core is respectively connected to the small chamber of the boom cylinder and the inlet of the boom overflow valve 1; the working oil port 2 of the boom valve core is respectively connected to the large chamber of the boom cylinder and the inlet of the boom overflow valve 2; the outlet of the boom overflow valve 1 and the outlet of the boom overflow valve 2 are respectively connected to the return oil port of the main valve; the compensation oil port of the boom valve core is connected to the inlet of the boom compensator; the control oil port 1 of the boom compensator is connected to the Ls port of the main valve, and the control oil port 2 of the boom compensator is connected to the return oil port of the main valve in sequence through a two-position two-way solenoid valve and a stable overflow valve; the stable overflow valve is used to keep the excavator working at a set working limit state.

[0006] Furthermore, the main valve is also provided with a first link, which includes a relief valve, the inlet of the relief valve is connected to the Ls port of the main valve, and the Ls port of the main valve is connected to the control port of the variable pump; the outlet of the relief valve is connected to the oil return port of the main valve; the set pressure of the stable relief valve is less than the working pressure of the relief valve.

[0007] Furthermore, the structure of the boom connection is the same as that of the arm connection.

[0008] Furthermore, it also includes a selection switch, which is provided with a neutral position, a boom control position and a boom control position; the boom control position is connected to the control end of the two-position two-way solenoid valve connected to the boom; the boom control position is connected to the control end of the two-position two-way solenoid valve connected to the boom, and at the same time, is connected to the control end of the two-position two-way solenoid valve connected to the boom through a connecting switch; the neutral position is used to keep the excavator working within the set working limit state; the boom control position is used to improve the working capacity of the excavator boom to break through the set working limit state; the boom control position is used to improve the working capacity of the excavator boom to break through the set working limit state.

[0009] Furthermore, when the selection switch is in the neutral position, the variable pump draws hydraulic oil from the hydraulic tank through the P port of the main valve into the boom valve core and the boom compensator of the boom link to act on the boom cylinder; when the boom cylinder receives the load pressure, it will transmit the pressure to the boom link's stabilizing relief valve through the two-position two-way solenoid valve of the boom link; when the load pressure is lower than the working pressure at which the whole machine becomes unstable, the whole machine works normally; when the load pressure is higher than the working limit state set by the boom link's stabilizing relief valve, the boom link's stabilizing relief valve will discharge the excess load pressure back to the hydraulic tank through the one-way valve.

[0010] Furthermore, when the selection switch is in the neutral position, the variable pump draws hydraulic oil from the hydraulic oil tank through the P port of the main valve into the boom valve core and boom compensator of the boom unit to act on the boom cylinder; when the boom cylinder receives the load pressure, it will transmit the pressure to the boom unit's stabilizing relief valve through the two-position two-way solenoid valve; when the load pressure is lower than the working pressure at which the whole machine becomes unstable, the whole machine works normally; when the load pressure is higher than the working limit state set by the boom unit's stabilizing relief valve, the boom unit's stabilizing relief valve will discharge the excess load pressure back to the hydraulic oil tank through the one-way valve.

[0011] Furthermore, when the selection switch is in the boom control position, the two-position two-way solenoid valve connected to the boom is energized, and the two-position two-way solenoid valve connected to the boom enters the left position, so that the stabilizing overflow valve is disconnected from the main oil circuit, and the working capacity of the boom cylinder is increased to the pressure setting value of the overflow valve.

[0012] Furthermore, when the selection switch is in the boom control position, the two-position two-way solenoid valve of the boom is energized, and the two-position two-way solenoid valve of the boom enters the left position, so that the stabilizing overflow valve of the boom is disconnected from the main oil circuit, and the working capacity of the boom cylinder is increased to the pressure setting value of the overflow valve.

[0013] Furthermore, when the selection switch is in the boom control position or the arm control position, and the connection switch is closed, the two-position two-way solenoid valves of the boom connection and the arm connection are energized and enter the left position, so that the stable relief valves of the boom connection and the arm connection are disconnected from the main oil circuit, and the working capacity of the boom cylinder and the arm cylinder are increased to the pressure setting value of the relief valve.

[0014] In a second aspect, an excavator is provided, characterized in that the excavator is equipped with the excavator hydraulic system according to the first aspect.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention drives the boom cylinder through a boom linkage, and the boom linkage includes a boom valve core, the inlet of the boom valve core is connected to the P port of the main valve, the working oil port 1 of the boom valve core is respectively connected to the small chamber of the boom cylinder and the inlet of the boom relief valve 1; the working oil port 2 of the boom valve core is respectively connected to the large chamber of the boom cylinder and the inlet of the boom relief valve 2; the outlet of the boom relief valve 1 and the outlet of the boom relief valve 2 are respectively connected to the return oil port of the main valve; the compensation oil port of the boom valve core is connected to the inlet of the boom compensator; the control oil port 1 of the boom compensator is connected to the Ls port of the main valve, and the control oil port 2 of the boom compensator is connected to the return oil port of the main valve in sequence through a two-position two-way solenoid valve and a stable relief valve; the stable relief valve is used to keep the excavator working at a set working limit state; it can make the excavator work stably according to the set load and avoid the problem of instability of the whole machine;

[0017] (2) The present invention also provides a channel for improving the capacity of the boom cylinder and the dipper cylinder. By setting a selection switch to control the boom cylinder and / or the dipper cylinder, it can be operated when the load exceeds the design load of the excavator. The excavator's working capacity is improved by artificial control, and the user is reminded that the excavator is currently in an overloaded working state. This can not only meet the user's occasional overload operation needs, but also achieve the purpose of reminding the user that the excavator is currently in an overloaded working state and should pay more attention to safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the working principle of an excavator hydraulic system provided by an embodiment of the present invention;

[0019] In the figure: 1. Boom cylinder; 2. Arm cylinder; 3. Hydraulic oil tank; 4. Variable pump; 5. Unloading valve; 6. Check valve; 7. Overflow valve; 8. Arm valve core; 9. Arm compensator; 10. Two-position two-way solenoid valve; 11. Stable overflow valve; 121. Arm overflow valve 1; 122. Arm overflow valve 2; 13. Selection switch; 14. Connecting switch. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0021] Example 1:

[0022] like Figure 1As shown, an excavator hydraulic system includes a boom cylinder 1, an arm cylinder 2, a hydraulic oil tank 3, a variable pump 4 and a main valve. The main valve includes a first connection, an arm connection, a boom connection and other working connections.

[0023] The hydraulic oil output by the variable pump 4 enters the P port of the main valve and enters the first coupling, the arm coupling, and the boom coupling respectively through the P port of the main valve. The first coupling includes a relief valve 7 and an unloading valve 5. The inlet of the relief valve 7 is connected to the Ls port of the main valve, and the Ls port of the main valve is connected to the control port of the variable pump 4. The outlet of the relief valve 7 is connected to the return oil port of the main valve, and the return oil port of the main valve is connected to the hydraulic oil tank 3 through a check valve 6. The inlet of the unloading valve 5 is connected to the P port of the main valve, and the outlet of the unloading valve 5 is connected to the return oil port of the main valve. The control port of the unloading valve 5 is connected to the Ls port of the main valve.

[0024] The boom connection is used to drive the boom cylinder, including the boom valve core 8. The inlet of the boom valve core 8 is connected to the P port of the main valve. The working oil port 1 of the boom valve core 8 is respectively connected to the small chamber of the boom cylinder 2 and the inlet of the boom overflow valve 121; the working oil port 2 of the boom valve core 8 is respectively connected to the large chamber of the boom cylinder 2 and the inlet of the boom overflow valve 2 122; the outlet of the boom overflow valve 121 and the outlet of the boom overflow valve 2 122 are respectively connected to the return oil port of the main valve.

[0025] The compensation oil port of the boom valve core 8 is connected to the inlet of the boom compensator 9; the control oil port 1 of the boom compensator 9 is connected to the Ls port of the main valve. The control oil port 2 of the boom compensator 9 is connected to the return oil port of the main valve through a two-position, two-way solenoid valve 10 and a stable relief valve 11. The stable relief valve 11 is used to maintain the excavator's operating limit. The advantage of placing the two-position, two-way solenoid valve 10 and the stable relief valve 11 after the boom compensator 9 is that it does not affect the normal operation of other main valves (such as travel speed and rotation speed).

[0026] The set pressure of the stable relief valve 11 is lower than the working pressure of the relief valve 7 .

[0027] The structure of the boom connection is the same as that of the arm connection.

[0028] The selection switch 13 is provided with a neutral position a, a boom control position b and a boom control position c; the boom control position b is connected to the control end of the two-position two-way solenoid valve 10 connected to the boom; the boom control position c is connected to the control end of the two-position two-way solenoid valve 10 connected to the boom, and at the same time, is connected to the control end of the two-position two-way solenoid valve 10 connected to the boom through the connecting switch 14; when the selection switch 13 is in the neutral position a, no signal is input, which is used to keep the excavator working within the set working limit state; when the selection switch 13 is in the boom control position b, the two-position two-way solenoid valve 10 connected to the boom is energized, which is used to improve the working capacity of the excavator boom to break through the set working limit state; when the selection switch 13 is in the boom control position c, the two-position two-way solenoid valve connected to the boom is energized, which is used to improve the working capacity of the excavator boom to break through the set working limit state.

[0029] When the selection switch 13 is in the neutral position a, the variable pump 4 draws hydraulic oil from the hydraulic oil tank 3 and enters the boom valve core 8 and boom compensator 9 of the boom link through the P port of the main valve to act on the boom cylinder 2; when the boom cylinder 2 receives the load pressure, it will transfer the pressure to the stabilizing relief valve 11 of the boom link through the two-position two-way solenoid valve 10 of the boom link; when the load pressure is lower than the working pressure at which the whole machine becomes unstable, the whole machine works normally; when the load pressure is higher than the working limit state set by the stabilizing relief valve 11 of the boom link, the stabilizing relief valve 11 of the boom link will discharge the excess load pressure back to the hydraulic oil tank 3 through the one-way valve 6.

[0030] Similarly, when the selection switch 13 is in the neutral position a, the variable pump 4 draws hydraulic oil from the hydraulic oil tank 3 and enters the boom valve core and boom compensator of the boom connection through the P port of the main valve to act on the boom cylinder 1; when the boom cylinder 1 receives the load pressure, it will transmit the pressure to the boom connection's stable relief valve through the boom connection's two-position two-way solenoid valve; when the load pressure is lower than the working pressure at which the whole machine becomes unstable, the whole machine works normally; when the load pressure is higher than the working limit state set by the boom connection's stable relief valve, the boom connection's stable relief valve will discharge the excess load pressure back to the hydraulic oil tank 3 through the one-way valve 6.

[0031] When the selection switch 13 is in the boom control position b (at this time, the connection switch 14 is disconnected; if the user wants to increase the working capacity of the boom, select this operation), the two-position two-way solenoid valve 10 connected to the boom is energized, and the two-position two-way solenoid valve 10 connected to the boom enters the left position, so that the stabilizing relief valve 11 is disconnected from the main oil circuit, and the working capacity of the boom cylinder is increased to the pressure setting value of the relief valve 7.

[0032] Similarly, when the selection switch 13 is in the boom control position c (at this time, the connection switch 14 is disconnected; if the user wants to increase the working capacity of the boom, select this operation), the two-position two-way solenoid valve of the boom is energized, and the two-position two-way solenoid valve of the boom enters the left position, so that the stabilizing relief valve of the boom is disconnected from the main oil circuit, and the working capacity of the boom cylinder is increased to the pressure setting value of the relief valve 7.

[0033] When the selection switch 13 is in the boom control position b or the arm control position c, and the connecting switch 14 is closed (if the user wants to increase the working capacity of the boom and the boom at the same time, select this operation), the two-position two-way solenoid valves of the boom connection and the boom connection are both energized and enter the left position, so that the stable relief valves of the boom connection and the boom connection are disconnected from the main oil circuit, and the working capacity of the boom cylinder and the boom cylinder are both increased to the pressure setting value of the relief valve 7.

[0034] The excavator hydraulic system described in this invention maintains a stable operating state by being in its initial position. Depending on specific work requirements, the excavator's operating capacity can be partially or fully released manually. This reminds the user that manually releasing the operating capacity will cause the entire excavator to become unstable, thereby enhancing safety awareness. This electro-hydraulic control system operates independently, unaffecting the performance of other main valve linkages in the excavator and preventing degradation of their operating performance.

[0035] Example 2:

[0036] Based on the excavator hydraulic system described in the first embodiment, this embodiment provides an excavator, which is equipped with the excavator hydraulic system described in the first embodiment.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An excavator hydraulic system, characterized in that: It includes a variable pump (4), wherein the hydraulic oil output by the variable pump (4) enters the P port of the main valve and respectively enters the arm link and the boom link through the P port of the main valve; The boom linkage is used to drive the boom cylinder, and includes a boom valve core (8). The inlet of the boom valve core (8) is connected to the P port of the main valve. The working oil port 1 of the boom valve core (8) is respectively connected to the small chamber of the boom cylinder (2) and the inlet of the boom overflow valve 1 (121); the working oil port 2 of the boom valve core (8) is respectively connected to the large chamber of the boom cylinder (2) and the inlet of the boom overflow valve 2 (122); the outlet of the boom overflow valve 1 (121) and the outlet of the boom overflow valve 2 (122) are respectively connected to the return oil port of the main valve. The compensation oil port of the boom valve core (8) is connected to the inlet of the boom compensator (9); the control oil port 1 of the boom compensator (9) is connected to the Ls port of the main valve, and the control oil port 2 of the boom compensator (9) is connected to the return oil port of the main valve through a two-position two-way solenoid valve (10) and a stable overflow valve (11) in sequence; the stable overflow valve (11) is used to keep the excavator working at a set working limit state; The device further comprises a selection switch (13), wherein the selection switch (13) is provided with a neutral position (a), a boom control position (b), and a boom control position (c); the boom control position (b) is connected to the control end of a two-position two-way solenoid valve (10) connected to the boom; the boom control position (c) is connected to the control end of the two-position two-way solenoid valve (10) connected to the boom, and is connected to the control end of the two-position two-way solenoid valve (10) connected to the boom via a connecting switch (14); The neutral position (a) is used to keep the excavator working within the set working limit state; the boom control position (b) is used to improve the working capacity of the excavator boom to break through the set working limit state; the boom control position (c) is used to improve the working capacity of the excavator boom to break through the set working limit state.

2. The hydraulic system for an excavator according to claim 1, characterized in that: The main valve is further provided with a first link, which includes a relief valve (7), the inlet of the relief valve (7) being connected to the Ls port of the main valve, and the Ls port of the main valve being connected to the control port of the variable pump (4); the outlet of the relief valve (7) being connected to the oil return port of the main valve; and the set pressure of the stable relief valve (11) being lower than the working pressure of the relief valve (7).

3. The hydraulic system for an excavator according to claim 2, characterized in that: The structure of the boom connection is the same as that of the arm connection.

4. The hydraulic system for an excavator according to claim 3, characterized in that: When the selector switch (13) is in the neutral position (a), the variable pump (4) draws hydraulic oil from the hydraulic oil tank (3) and enters the boom valve core (8) and boom compensator (9) of the boom linkage through the P port of the main valve to act on the boom cylinder (2); when the boom cylinder (2) receives the load pressure, it transmits the pressure to the boom linkage stabilization relief valve (11) through the two-position two-way solenoid valve (10); when the load pressure is less than the working pressure at which the whole machine becomes unstable, the whole machine operates normally; when the load pressure is higher than the working limit state set by the boom linkage stabilization relief valve (11), the boom linkage stabilization relief valve (11) releases the excess load pressure back to the hydraulic oil tank (3) through the one-way valve (6).

5. The hydraulic system for an excavator according to claim 3, characterized in that: When the selector switch (13) is in the neutral position (a), the variable pump (4) draws hydraulic oil from the hydraulic oil tank (3) and enters the boom valve core and boom compensator of the boom unit through the P port of the main valve to act on the boom cylinder (1); when the boom cylinder (1) receives the load pressure, it transmits the pressure to the stabilizing relief valve of the boom unit through the two-position two-way solenoid valve of the boom unit; when the load pressure is lower than the working pressure at which the whole machine loses stability, the whole machine works normally; when the load pressure is higher than the working limit state set by the stabilizing relief valve of the boom unit, the stabilizing relief valve of the boom unit releases the excess load pressure back to the hydraulic oil tank (3) through the one-way valve (6).

6. The hydraulic system for an excavator according to claim 3, characterized in that: When the selector switch (13) is in the boom control position (b), the two-position two-way solenoid valve (10) of the boom is energized and enters the left position, so that the stabilizing relief valve (11) is disconnected from the main oil circuit, and the working capacity of the boom cylinder is increased to the pressure setting value of the relief valve (7).

7. The hydraulic system for an excavator according to claim 3, characterized in that: When the selector switch (13) is in the boom control position (c), the two-position two-way solenoid valve of the boom is energized and enters the left position, so that the stabilizing relief valve of the boom is disconnected from the main oil circuit, and the working capacity of the boom cylinder is increased to the pressure setting value of the relief valve (7).

8. The hydraulic system for an excavator according to claim 6 or 7, characterized in that: When the selector switch (13) is in the arm control position (b) or the boom control position (c), and the connection switch (14) is closed, The two-position two-way solenoid valves of the boom and the dipper link are both energized and enter the left position, so that the stable relief valves of the boom and the dipper link are disconnected from the main oil circuit, and the working capacity of the boom cylinder and the dipper cylinder is increased to the pressure setting value of the relief valve (7).

9. An excavator, characterized in that: The excavator is equipped with the excavator hydraulic system according to any one of claims 1 to 8.

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