Swing control system and excavator

Abstract

The application discloses a slewing control system and an excavator, and belongs to the technical field of engineering machinery. The application aims to solve the abnormal situation that the electric slewing speed becomes slow or even stops due to the pressure source fluctuation of a pilot pressure reducing valve group, and realizes the normal action of controlling the electric slewing and the hydraulic slewing by not canceling the main valve slewing control joint, controlling the LS pressure, and collecting the pressure from a pilot handle.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, and in particular to a slewing control system and an excavator. Background Technology

[0002] Currently, most mini excavators employ load-sensitive hydraulic systems, equipped with a main pump. The pilot oil route is led from the main pump outlet, pressure-reduced by a pressure-reducing valve, and then supplied to each control handle. The main valve's idle overflow pressure is generally lower than the pilot pressure-reducing valve's set pressure to reduce idle energy consumption. For hydraulic systems where the swing and main pump are driven by a motor, with the rest hydraulically controlled, only a pressure sensor is added at the pilot handle port. During single-action swing, the pressure sensor detects the maximum pilot pressure as the main valve's idle overflow pressure. However, during combined actions, the pressure sensor detects the maximum pilot pressure as the pressure-reducing valve's outlet pressure. Because these two pressures differ, situations may occur where the speed of switching between combined actions and single-action swing slows down, vibrates, or even stops. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a slewing control system and excavator to solve the abnormal situation where the slewing speed slows down or even stops due to pressure source fluctuations in the pilot pressure reducing valve group.

[0004] To solve the above-mentioned technical problems, the present invention is implemented using the following solution:

[0005] This invention provides a slewing control system, including a hydraulic oil tank, a load-sensitive pump, a main valve, a pilot valve, a check valve, a directional valve, an electro-proportional relief valve, a pressure sensor, a motor controller, and a slewing motor. The inlet of the load-sensitive pump is connected to the hydraulic oil tank, and the outlet is connected to the inlet of the main valve and the pilot valve. The feedback pressure oil of the slewing control link LS in the main valve and the feedback pressure oil of the working control link LS in the main valve (excluding the initial link and the slewing control link) converge at the initial link through different oil circuits. The check valve is connected to the working control link LS in the main valve (excluding the initial link and the slewing control link). The feedback pressure oil is located on the oil line; the inlet of the directional valve is connected to the inlet of the main valve, and the outlet is connected to the inlet of the rotary control link. The hydraulic control end is connected to the working control link LS of the main valve (excluding the first link and the rotary control link) on the oil line containing the feedback pressure oil and is located before the inlet of the check valve; the working port of the rotary control link is blocked; the inlet of the electro-proportional relief valve is connected to the outlet of the rotary control link, and the outlet is connected to the return oil line of the main valve; the pressure sensor, motor controller, and rotary motor are electrically connected in sequence, and the rotary pilot oil line is connected to the pressure sensor.

[0006] Optionally, the pilot oil circuit is connected to the control pilot side of each working control valve in the main valve and controls the switching of the control valve.

[0007] Optionally, the pilot includes a control handle and a pilot pressure reducing valve assembly, the inlet of which is connected to the outlet of the load-sensitive pump, and the outlet is connected to the inlet of the control handle.

[0008] Optionally, the pressure reducing valve is a fixed-value pressure reducing valve.

[0009] Optionally, the reversing valve is an electro-hydraulic controlled two-position two-way reversing valve.

[0010] This invention also provides a slewing control system, including a hydraulic oil tank, a load-sensitive pump, a main valve, a pilot valve, a check valve, an electro-proportional relief valve, a directional valve, a controller, and a slewing hydraulic motor; the inlet end of the load-sensitive pump is connected to the hydraulic oil tank, and the outlet end is connected to the inlet ends of the main valve and the pilot valve; the feedback pressure oil of the slewing control link LS in the main valve and the feedback pressure oil of the working control link LS in the main valve (excluding the initial link and the slewing control link) converge at the initial link through different oil circuits; the check valve is connected to the working control link LS in the main valve (excluding the initial link and the slewing control link). The feedback pressure oil is located on the oil line; the inlet of the electro-proportional relief valve is connected to the outlet of the rotary control link, and the outlet is connected to the return oil line of the main valve; the inlet of the directional valve is connected to the inlet of the main valve, and the outlet is connected to the inlet of the rotary control link; the hydraulic control end is connected to the oil line where the feedback pressure oil of the working control link LS is located in the main valve (excluding the first link and the rotary control link) and is located before the inlet of the check valve; the electrical control end is connected to the controller, and the controller is electrically connected to the electro-proportional relief valve; the working oil port of the rotary control link is connected to the working oil port of the rotary hydraulic motor.

[0011] Optionally, the reversing valve is an electro-hydraulic controlled two-position two-way reversing valve.

[0012] The present invention also provides an excavator equipped with the aforementioned slewing control system.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0014] 1. This invention achieves stable control of electric rotary single-action / compound action and input pressure, avoiding the situation where pressure fluctuations caused by pump idling lead to slowing down, shaking, or even stopping of rotary single-action switching between compound actions.

[0015] 2. This invention achieves the change of rotary action from electrical control to hydraulic control without changing the main valve, thereby improving the versatility of the main valve. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a rotary control system provided in an embodiment of the present invention;

[0017] In the diagram: 1. Hydraulic oil tank; 2. Load-sensitive pump; 3. Main valve; 4. Pilot; 5. Pressure sensor; 6. Motor controller; 7. Slewing motor; 8. Boom cylinder; 9. Electro-proportional relief valve; 10. Controller; 11. Check valve; 12. Electro-hydraulic two-position two-way directional valve. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example 1:

[0019] like Figure 1 As shown, this embodiment provides a slewing control system, which mainly consists of a hydraulic oil tank 1, a load-sensitive pump 2, a main valve 3, a pilot valve 4, a check valve 11, an electro-hydraulic two-position two-way directional valve 12, an electro-proportional relief valve 9, a pressure sensor 5, a motor controller 6, and a slewing motor 7.

[0020] Specifically, the inlet of the load-sensitive pump 2 is connected to the hydraulic oil tank 1, and the outlet is connected to the inlet of the main valve 3 and the pilot 4. The feedback pressure oil of the rotary control link LS in the main valve 3 and the feedback pressure oil of the working control link LS in the main valve (excluding the first link and rotary control link) converge at the first link through different oil circuits. The check valve 11 is connected to the oil circuit of the working control link LS feedback pressure oil in the main valve 3 (excluding the first link and rotary control link). The inlet of the electro-hydraulic two-position two-way directional valve 12 is connected to the inlet of the main valve 3, the outlet is connected to the inlet of the rotary control link, and the hydraulic control end is connected to the oil circuit of the working control link LS feedback pressure oil in the main valve 3 (excluding the first link and rotary control link) and is located before the inlet of the check valve 11. The working ports (i.e., ports A1 and B1) of the rotary control link are blocked; the inlet of the electro-proportional relief valve 9 is connected to the outlet of the rotary control link, and the outlet is connected to the return oil circuit of the main valve 3. Pressure sensor 5, motor controller 6, and rotary motor 7 are electrically connected in sequence. The rotary pilot oil circuit is connected to pressure sensor 5. Pilot 4 includes an operating handle and a pilot pressure reducing valve assembly (a set-value pressure reducing valve: a hydraulic valve that reduces the input pressure P to a set value P0 for output; P ≥ P0 is required; when P < P0, then P0 = P). The inlet of the pilot pressure reducing valve assembly is connected to the outlet of the load-sensitive pump 2, and the outlet is connected to the inlet of the operating handle. The pilot oil circuit is connected to the control pilot side of the control valves in each working control link (rotation control link, boom control link, and other working control links) within the main valve 3 and controls the reversing of the control valves.

[0021] Working principle:

[0022] The load-sensitive pump 2 draws oil from the hydraulic oil tank 1. One outlet oil flows into the pilot pressure relief handle, supplying oil to the pilot 4, while another flows through the P2 port of the main valve 3 to the main valve, supplying oil to the main oil circuit. For the pilot pressure relief oil supply section, in this embodiment, the slewing control link is set as the first link, the boom control link as the second link, and other working control links. The slewing pilot oil circuits pa1 / pb1 are connected not only to the control pilot side of the control valve in the slewing control link within the main valve 3, but also to the pressure sensor 5. That is, the slewing pilot pressure signal is converted into an electrical signal, which, after processing by the motor controller 6, sends a control signal to the slewing motor 7, thereby controlling the slewing motor 7 to operate. The hydraulic pressure of the electro-hydraulic two-position two-way directional valve 12 is controlled by feedback pressure from the working control link LS, excluding the first link and the slewing control link.

[0023] When the slewing action is achieved by electric rotation, the main valve slewing linkage is not canceled, and the electro-hydraulic two-position two-way directional valve 12 has no input electrical signal. When performing a compound action or operating the handle, i.e., when the pilot 4 pressure reducing handle operating part outputs a pressure signal from the relevant pilot port, the working control linkage LS (excluding the first linkage and slewing control linkage) has feedback pressure. The LS feedback pressure oil is output to the hydraulic control end of the electro-hydraulic two-position two-way directional valve 12, thereby controlling the electro-hydraulic two-position two-way directional valve 12 to switch to the left position. At this time, the main oil circuit does not pass through the slewing control linkage of the main valve 3, so other actions will not fail due to its low overflow pressure. At this time, the pilot oil source can output a stable pressure. The pilot pressure pa1 / pb1 changes with the angle of the operating handle, thereby changing the output signal of the pressure sensor 5. That is, the slewing pilot pressure signal is converted into an electrical signal. After being processed by the motor controller 6, a control signal can be sent to the slewing motor 7, thereby controlling the slewing motor 7 to operate and achieve different slewing speeds. When only the slewing single action is performed, the working control link LS (excluding the slewing link) has no feedback pressure. Due to the presence of check valve 11, the feedback pressure oil from the slewing control link LS will not be output to the hydraulic control end of the electro-hydraulic two-position two-way directional valve 12. The electro-hydraulic two-position two-way directional valve 12 does not switch and remains in the right position. Since the A / B ports of the main valve 3 slewing link are blocked, the feedback pressure of the slewing control link LS is the pressure set by the electro-proportional relief valve 9. By adjusting the pressure set by the electro-proportional relief valve 9, the oil source pressure at the pilot pressure reducing section input port (slewing single action) is adjusted. During operation, the oil source pressure at the pilot pressure reducing section input port (the feedback pressure of the slewing control linkage LS + the idle overflow pressure of the main valve 3) is greater than the pressure reducing valve set pressure. At this time, the pilot oil source can be guaranteed to output stable pressure. The pilot pressure pa1 / pb1 will change with the angle of the operating handle, thereby changing the output signal of the pressure sensor 5. That is, the slewing pilot pressure signal is converted into an electrical signal. After being processed by the motor controller 6, a control signal can be sent to the slewing motor 7, thereby controlling the slewing motor 7 to operate and realize the control of its different slewing speeds.

[0024] In summary, in this embodiment, by controlling the pressure signal fed back from the main valve 3LS port, the oil source pressure at the input port of the pilot pressure reducing section can be made greater than the set pressure of the pressure reducing valve, regardless of whether it is a single or compound electric rotation action, thereby stabilizing its output pressure and solving the abnormal situation where the electric rotation speed slows down or even stops due to pressure source fluctuations in the pilot pressure reducing valve group. Example 2:

[0025] This embodiment provides a slewing control system, which mainly consists of a hydraulic oil tank 1, a load-sensitive pump 2, a main valve 3, a pilot valve 4, a check valve 11, an electro-proportional relief valve 9, an electro-hydraulic two-position two-way directional valve 12, a controller 10, and a slewing hydraulic motor.

[0026] Specifically, the inlet of the load-sensitive pump 2 is connected to the hydraulic oil tank 1, and the outlet is connected to the inlet of the main valve 3 and the pilot 4. The feedback pressure oil of the rotary control link LS within the main valve 3 and the feedback pressure oil of the working control link LS within the main valve (excluding the initial link and rotary control link) converge at the first link through different oil circuits. The check valve 11 is connected to the oil circuit containing the feedback pressure oil of the working control link LS within the main valve 3 (excluding the initial link and rotary control link). The inlet of the electro-proportional relief valve 9 is connected to the outlet of the rotary control link, and the outlet is connected to the return oil circuit of the main valve 3. The inlet of the electro-hydraulic two-position two-way directional valve 12 is connected to the inlet of the main valve 3, and the outlet is connected to the inlet of the rotary control link. The hydraulic control end is connected to the oil circuit containing the feedback pressure oil of the working control link LS within the main valve 3 (excluding the initial link and rotary control link) and is located before the inlet of the check valve 11. The electro-hydraulic control end is connected to the controller 10, and the controller 10 is electrically connected to the electro-proportional relief valve 9. The working ports of the slewing control linkage (i.e., ports A1 and B1) are connected to the working ports of the slewing hydraulic motor (i.e., ports A / B). Pilot 4 includes an operating handle and a pilot pressure reducing valve assembly (a set-value pressure reducing valve: a hydraulic valve that reduces the input pressure P to a set value P0 for output; P ≥ P0 is required; when P < P0, then P0 = P). The inlet of the pilot pressure reducing valve assembly is connected to the outlet of the load-sensitive pump 2, and the outlet is connected to the inlet of the operating handle. The pilot oil circuit connects to the control pilot side of the control valves in each working control linkage (slewing control linkage, boom control linkage, and other working control linkages) within the main valve 3 and controls the reversing of the control valves.

[0027] Working principle:

[0028] The load-sensitive pump 2 draws oil from the hydraulic oil tank 1. One outlet oil flows into the pilot pressure reducing handle, supplying oil to the pilot 4; the other flows through the P2 port of the main valve 3 to the main valve, supplying oil to the main oil circuit. For the pilot pressure reducing oil supply section, in this embodiment, the slewing is set as the first connection, the boom as the second connection, and other working connections. The electro-hydraulic two-position two-way directional valve 12 is electrically controlled by the output signal from the controller 10.

[0029] When the slewing action is achieved, the pressure of the electro-proportional relief valve 9 at the main valve 3 port is increased. The controller 10 sends an electrical signal to the electro-hydraulic two-position two-way directional valve 12 to put it in the right position (normal position). The main valve slewing control A1 / B1 port is connected to the slewing hydraulic motor A / B port. This allows the slewing action to be changed from electro-controlled to hydraulic-controlled without changing the main valve 3. The combined action is also hydraulic-controlled. The hydraulic control mode is the conventional control mode, so it will not be described in detail here. Example 3:

[0030] This embodiment provides an excavator equipped with the slewing control system described in Embodiment 1 or Embodiment 2.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A slewing control system, characterized by, The hydraulic system comprises a hydraulic oil tank, a load-sensitive pump, a main valve, a pilot, a check valve, a reversing valve, an electric proportional overflow valve, a pressure sensor, a motor controller and a rotary motor; the oil inlet end of the load-sensitive pump is connected with the hydraulic oil tank, and the oil outlet end is connected with the oil inlet end of the main valve and the pilot; the rotary control link LS feedback pressure oil in the main valve is combined with the working control link LS feedback pressure oil in the main valve except the first link and the rotary control link through different oil paths; the check valve is connected to the oil path of the working control link LS feedback pressure oil in the main valve except the first link and the rotary control link; the oil inlet end of the reversing valve is connected with the oil inlet end of the main valve, the oil outlet end is connected with the oil inlet end of the rotary control link, and the hydraulic control end is connected to the oil path of the working control link LS feedback pressure oil in the main valve except the first link and the rotary control link and is located in front of the oil inlet end of the check valve; the working oil port of the rotary control link is in a blocking state; the oil inlet end of the electric proportional overflow valve is connected with the oil outlet end of the rotary control link, and the oil outlet end is connected with the oil return path of the main valve; the pressure sensor, the motor controller and the rotary motor are electrically connected in sequence, and the rotary pilot oil path is connected with the pressure sensor. The pilot comprises a control handle and a pilot pressure reducing valve group, the oil inlet end of the pilot pressure reducing valve group is connected with the oil outlet end of the load-sensitive pump, and the oil outlet end is connected with the oil inlet end of the control handle; the pressure reducing valve is a constant value pressure reducing valve.

2. The slewing control system according to claim 1, wherein The pilot oil path is connected with the control pilot side of the control valve in each working control link in the main valve and controls the reversing of the control valve.

3. The slewing control system of claim 1, wherein The reversing valve is an electro-hydraulic control two-position two-way reversing valve.

4. An excavator characterized by comprising: The excavator is provided with the rotary control system according to any one of claims 1 to 3.

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