Palm vehicle hydraulic control system

Abstract

The invention relates to the technical field of hydraulic control, in particular to a palm vehicle hydraulic control system. The system comprises a main control system and a pilot control system, the main control system comprises a main control valve, a first gear pump and a second gear pump, the first gear pump and the second gear pump are connected to an oil tank, a left loop and a right loop are arranged in the main control valve, and the first gear pump and the second gear pump are connected to the two loops respectively for oil supply; each control link is connected to the working cavity of the corresponding execution element; a double-pump hydraulic system is adopted, seven hydraulic actions of the palm vehicle are uniformly distributed on two hydraulic pumps, the load fatigue of a single-pump system is reduced, the service life of the pumps is prolonged, the faults of the hydraulic pumps are reduced, and the fault-free service time of a user is greatly prolonged; hydraulic actions controlled by the first gear pump and the second gear pump can act simultaneously to complete composite motion, and the defects that a single-pump hydraulic system cannot complete hydraulic composite motion and the working efficiency is reduced are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and particularly relates to a hydraulic control system for a palm truck. Background Art

[0002] A palm truck is a special working vehicle used for operations such as palm fruit collection, handling, and loading. Its hydraulic control system is a key component for realizing the actions of various on-vehicle actuators. The existing hydraulic systems for palm trucks mostly adopt a single-pump single-circuit oil supply structure, and different actuators cannot perform combined actions. At the same time, to control costs, some systems only adopt a simple on-off type pilot control method, which is difficult to meet the requirements for the smoothness and speed adjustability of the actions of key actuators (such as the boom and stick). Summary of the Invention

[0003] The purpose of the present invention is to provide a reasonably designed hydraulic control system for a palm truck to solve the above-mentioned defects in view of the deficiencies and drawbacks of the prior art.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: It includes a main control system and a pilot control system. The main control system includes a main control valve, a first gear pump and a second gear pump connected to a fuel tank. There are two left and right circuits in the main control valve. The first gear pump and the second gear pump are respectively connected to the two circuits for oil supply. There are multiple control joints in the main control valve, namely a boom control joint, a bucket control joint, a gripper tightening control joint, a carriage lifting control joint, a gripper slewing control joint, a stick control joint, and a turret slewing control joint. Among them, the boom control joint, the bucket control joint, and the gripper tightening control joint are all arranged in the left circuit, and the remaining control joints are arranged in the right circuit; each control joint is connected to the working chamber of the corresponding actuator. The pilot control system includes a first pilot hydraulic handle, a second pilot hydraulic handle, a pilot control valve group, and a pilot gear pump. The pressure output end of the pilot gear pump is connected to the pilot control valve group. Both the first pilot hydraulic handle and the second pilot hydraulic handle are connected to the hydraulic circuits in the pilot control valve group. There is a pilot main solenoid valve and multiple electromagnetic directional valves in the hydraulic circuits of the pilot control valve group. The first pilot hydraulic handle, the second pilot hydraulic handle, and multiple solenoid valves are all connected behind the pilot main solenoid valve; the hydraulic signals output by the pilot control valve group are connected to the pilot chambers of the proportional spools of the main control valve.

[0005] Preferably, a boom cylinder is connected to the boom control joint, a bucket cylinder is connected to the bucket control joint, a gripper tightening cylinder is connected to the gripper tightening control joint, a carriage lifting cylinder is connected to the carriage lifting control joint, a gripper slewing motor is connected to the gripper slewing control joint, a stick cylinder is connected to the stick control joint, and a turret slewing cylinder is connected to the turret slewing control joint.

[0006] Preferably, the multiple electromagnetic directional control valves are, in sequence, the gripper left - hand rotation solenoid valve, the gripper right - hand rotation solenoid valve, the carriage lowering solenoid valve, the carriage raising solenoid valve, the gripper clamping solenoid valve, and the gripper releasing solenoid valve.

[0007] Preferably, a pilot filter is provided at the oil inlet port of the pilot control valve group, and a pilot main relief valve is provided between the outlet of the pilot filter and the oil return circuit in the pilot control valve group.

[0008] Preferably, a check valve one is connected to the rear end of the pilot filter, and a check valve two for providing bypass protection is connected in parallel to the pilot filter.

[0009] Preferably, a left - hand circuit relief valve is provided in the left circuit, and a right - hand circuit relief valve is provided in the right circuit.

[0010] Preferably, in the left circuit, a buffer valve one and a buffer valve two are respectively provided in the two oil circuits connected to the boom cylinder; in the right circuit, a buffer valve four and a buffer valve five are respectively provided in the two oil circuits connected to the turret slewing cylinder, and a buffer valve three is provided in the oil return circuit of the stick cylinder.

[0011] Preferably, a suction filter is connected between the first gear pump and the fuel tank, a second suction filter is connected between the second gear pump and the fuel tank, and a third suction filter is provided between the pilot gear pump and the fuel tank; a high - pressure filter one is provided behind the first gear pump, a high - pressure filter two is connected behind the second gear pump, and a high - pressure filter three is connected to the rear end of the pilot gear pump.

[0012] Preferably, a radiator is provided on the oil return path connected to the control port of the main control valve.

[0013] After adopting the above - mentioned structure, the beneficial effects of the present invention are as follows: 1. In the present invention, the hydraulic control system of the palm truck is a double - pump hydraulic system, which distributes the seven hydraulic actions of the palm truck evenly to two hydraulic pumps, reduces the load fatigue of the single - pump system, extends the service life of the pump, reduces the faults of the hydraulic pump, and greatly extends the trouble - free use time of the user.

[0014] 2. In the present invention, the first gear pump controls three groups of hydraulic actions of the boom, bucket, and gripper clamping and releasing, and the second gear pump controls four groups of hydraulic actions of the carriage, gripper slewing, stick, and turret. The hydraulic actions controlled by the first gear pump and the second gear pump can act simultaneously to complete compound movements, overcoming the defect that the single - pump hydraulic system cannot complete hydraulic compound actions and reducing the operation efficiency.

[0015] 3. In the present invention, a pilot control system is adopted to control the proportional spool of the main valve, which can select on - off control or proportional control according to the action requirements of different actuators, ensuring both the smooth operation of key actions and taking into account the system cost control.

[0016] 4. In the present invention, the system is provided with overflow valves, buffer valves and check valve structures for the main circuit and the pilot circuit, which can achieve automatic pressure relief and oil compensation when the actuator malfunctions or changes rapidly, avoid problems such as air suction and impact, and improve the safety and stability of the system.

[0017] 5. In the present invention, through the combined action of the pilot hydraulic handle and the electromagnetic directional valve, rapid response and fine adjustment of the actuator action are achieved. In particular, key actions such as the boom and bucket have good proportional control capabilities, significantly improving the operating comfort.

[0018] 6. In the present invention, the system is provided with multi-stage filters and radiators to ensure the oil cleanliness and temperature control, effectively prevent system contamination and overheating, and improve the service life and overall reliability of hydraulic components. Description of the Drawings

[0019] Figure 1 is the hydraulic schematic diagram of the main control system in the present invention; Figure 2 is the hydraulic schematic diagram of the main control system when the boom cylinder and the stick cylinder perform combined actions in the present invention; Figure 3 is the hydraulic schematic diagram of the pilot control system in the present invention; Figure 4 is the schematic diagram of the pilot control system when the boom descends and the gripper rotates left in the present invention.

[0020] Description of the Reference Numerals in the Drawings: 1, fuel tank; 2, suction filter; 3, gear pump I; 4, high-pressure filter I; 5, radiator; 6, main control valve; 7, boom cylinder; 8, bucket cylinder; 9, gripper tightening and loosening cylinder; 10, carriage lifting cylinder; 11, gripper slewing motor; 12, stick cylinder; 13, turret slewing cylinder; 14, high-pressure filter II; 15, gear pump II; 16, suction filter II; 601, left overflow valve; 602, boom control connection; 603, buffer valve I; 604, buffer valve II; 605, bucket control connection; 606, gripper tightening and loosening control connection; 607, carriage lifting control connection; 608, gripper slewing control connection; 609, buffer valve III; 610, stick control connection; 611, buffer valve IV; 612, buffer valve V; 613, turret slewing control connection; 614, right overflow valve; 17, suction filter III; 18, pilot gear pump; 19, high-pressure filter III; 20, pilot control valve group; 21, pilot hydraulic handle I; 22, pilot hydraulic handle II; 2001, Grab Left Rotation Solenoid Valve; 2002, Grab Right Rotation Solenoid Valve; 2003, Carriage Lowering Solenoid Valve; 2004, Carriage Lifting Solenoid Valve; 2005, Grab Clamping Solenoid Valve; 2006, Grab Releasing Solenoid Valve; 2007, Pilot Main Solenoid Valve; 2008, Pilot Main Relief Valve; 2009, Check Valve 1; 2010, Pilot Filter; 2011, Check Valve 2. Detailed Implementation Manner

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] As Figure 1 , 3 shown, it includes a main control system and a pilot control system; the main control system includes a main control valve 6 and a gear pump 1 3 and a gear pump 2 15 respectively connected to the fuel tank 1; the main control valve 6 internally has a left circuit and a right circuit, and the gear pump 1 3 and the gear pump 2 15 respectively provide hydraulic oil for the left and right circuits; the main control valve 6 is provided with a plurality of control joints, namely a boom control joint 602, a bucket control joint 605, a grab clamping and releasing control joint 606, a carriage lifting and lowering control joint 607, a grab rotation control joint 608, a stick control joint 610 and a turret rotation control joint 613; among them, the boom control joint 602, the bucket control joint 605 and the grab clamping and releasing control joint 606 are arranged in the left circuit, and the remaining control joints are arranged in the right circuit; each control joint is connected to the working chamber of the corresponding actuator; Among them, the boom control joint 602 is connected to the boom cylinder 7, the bucket control joint 605 is connected to the bucket cylinder 8, the grab clamping and releasing control joint 606 is connected to the grab clamping and releasing cylinder 9, the carriage lifting and lowering control joint 607 is connected to the carriage lifting and lowering cylinder 10, the grab rotation control joint 608 is connected to the grab rotation motor 11, the stick control joint 610 is connected to the stick cylinder 12, and the turret rotation control joint 613 is connected to the turret rotation cylinder 13; The pilot control system includes a pilot gear pump 18, a first pilot hydraulic handle 21, a second pilot hydraulic handle 22, and a pilot control valve group 20; the pressure output end of the pilot gear pump 18 is connected to the pilot control valve group 20, and the first pilot hydraulic handle 21 and the second pilot hydraulic handle 22 are connected to the hydraulic circuits in the pilot control valve group 20; the pilot control valve group 20 is provided with a pilot main solenoid valve 2007 and a plurality of electromagnetic directional valves; the pilot hydraulic handles are connected to the plurality of solenoid valves behind the pilot main solenoid valve 2007; the hydraulic signals output by the pilot control valve group 20 are connected to the pilot chambers of the proportional spools in the main control valve 6, so as to achieve the pilot control of each actuator in the main control system; the plurality of electromagnetic directional valves include: a gripper left rotation solenoid valve 2001, a gripper right rotation solenoid valve 2002, a carriage lowering solenoid valve 2003, a carriage raising solenoid valve 2004, a gripper clamping solenoid valve 2005, and a gripper loosening solenoid valve 2006, which respectively control the action directions or state switching of each mechanism; In the hydraulic oil circuit, in order to ensure the safety and stability of the system operation, a pilot filter 2010 is provided at the oil inlet port of the pilot control valve group 20, a pilot main relief valve 2008 is provided between the outlet of the pilot filter 2010 and the return oil circuit, a check valve 2009 is provided at the rear end of the filter, and a check valve 2011 for providing bypass protection is provided in parallel on the pilot filter 2010; A left circuit relief valve 601 is provided in the left circuit of the main control system, and a right circuit relief valve 614 is provided in the right circuit; in the left circuit, a first buffer valve 603 and a second buffer valve 604 are respectively provided in the two oil circuits connected to the boom cylinder 7; in the right circuit, a fourth buffer valve 611 and a fifth buffer valve 612 are respectively provided in the two oil circuits connected to the turret slewing cylinder 13; a third buffer valve 609 is provided in the return oil circuit of the bucket cylinder 12 to reduce impact and improve the response stability of the system; In addition, in order to ensure the quality of the hydraulic oil, an oil suction filter 2 is provided between the first gear pump 3 and the fuel tank 1, an oil suction filter 16 is provided between the second gear pump 15 and the fuel tank 1, and an oil suction filter 17 is provided between the pilot gear pump 18 and the fuel tank 1; the outlet of the first gear pump 3 is connected to a high-pressure filter 4, the outlet of the second gear pump 15 is connected to a high-pressure filter 14, and the outlet of the pilot gear pump 18 is connected to a high-pressure filter 19; Radiators 5 are provided on the return oil paths of each control connection of the main control valve 6 to reduce the temperature of the hydraulic oil and ensure the long-term stable operation of the system.

[0023] In the main control system, the left loop and the right loop are respectively supplied with oil by gear pump 1 - 3 and gear pump 2 - 15. Therefore, the two can work independently, that is, the actuators driven by the two can act simultaneously. For example, the boom cylinder 7 and the stick cylinder 12 can act simultaneously, and the boom cylinder 7 and the turret slewing cylinder 13 can also act simultaneously, achieving the purpose of compound movement, improving the operation efficiency of the machine, and improving the driving experience of the driver. Moreover, various hydraulic actions of the palm truck are evenly distributed to the two gear pumps at the same time, reducing the working time and labor intensity of the gear pump, increasing the service life of the gear pump, and extending the trouble-free operation time of the hydraulic system test. The control methods of each hydraulic actuator are as follows: the boom cylinder 7 is controlled by hydraulic proportion, the bucket cylinder 8 is controlled by hydraulic proportion, the gripper tightening cylinder 9 is controlled by switch, the carriage lifting cylinder 10 is controlled by switch, the gripper slewing motor 11 is controlled by switch, the stick cylinder 12 is controlled by hydraulic proportion, and the turret slewing cylinder 13 is controlled by hydraulic proportion; See Figure 2 , taking the compound action of the boom cylinder 7 and the stick cylinder 12 as an example for illustration: The spool pilot chamber b1 of the boom control union 602 receives a proportional pressure signal, and the spool opening can be adjusted proportionally, so as to realize the proportional control of the telescopic movement of the boom cylinder 7. Gear pump 1 - 3 sucks oil from the hydraulic oil tank 1 through the suction filter 2 - 1. The pressurized oil output by it successively passes through the high-pressure filter 1 - 4 and the lower channel of the boom control union 602, and enters the lower chamber of the boom cylinder 7 to drive the cylinder to extend. At the same time, the oil returning from the upper chamber of the boom cylinder 7 passes through the lower channel of the boom control union 602, flows through the radiator 5, and finally returns to the hydraulic oil tank 1. The left circuit relief valve 601 set in the left circuit is used to control the system pressure and play a safety protection role. The cushion valve 1 - 603 and the cushion valve 2 - 604 set in the oil circuits of the two chambers of the boom cylinder 7 are used to protect the cylinder. And when the oil supply in a certain chamber of the cylinder is insufficient due to too fast movement speed, automatic oil replenishment can be realized through the check valve built in the cushion valve to prevent the occurrence of air suction phenomenon; At the same time, the spool pilot chamber b6 of the stick control union 610 receives a proportional pressure signal, and its spool opening can also be adjusted proportionally to realize the proportional control of the telescopic movement of the stick cylinder 12. Gear pump 2 - 15 sucks oil from the hydraulic oil tank 1 through the suction filter 2 - 16. The pressurized oil output by it successively passes through the high-pressure filter 2 - 14 and the lower channel of the stick control union 610, and enters the lower chamber of the stick cylinder 12 to drive the cylinder to extend. The oil returning from the upper chamber of the stick cylinder 12 passes through the lower channel of the stick control union 610, flows through the radiator 5, and finally returns to the hydraulic oil tank 1; Through the above control method, the simultaneous action of the boom cylinder 7 and the stick cylinder 12 can be realized, and the pressure and flow rate of the two do not interfere with each other during the operation process, so that the lifting mechanism of the palm truck can complete the compound action.

[0024] The pilot control system provides pilot control pressure for the main control valve 6. The pilot pressure signals are divided into two categories: The first category is the switch hydraulic signal. The main control valve 6 spool controlled by such a signal has three fixed positions: upper position, middle position, and lower position, meeting the control requirements of the palm truck hydraulic actuator for simple switch actions, and achieving the expected functions on the premise of being economical and applicable. The three actions of the palm truck's carriage lifting, gripper tightening, and gripper rotation are all controlled by switch hydraulic signals. The corresponding electromagnetic directional valves include: gripper left rotation solenoid valve 2001, gripper right rotation solenoid valve 2002, carriage lowering solenoid valve 2003, carriage lifting solenoid valve 2004, gripper tightening solenoid valve 2005, and gripper loosening solenoid valve 2006; The second category is the hydraulic proportional control signal. The four groups of actions of the boom, bucket, arm, and turret rotation have an important impact on the comfort of the vehicle operation and the smoothness of operation. Therefore, hydraulic proportional control signals are adopted. The opening of the proportional spool in the boom control union 602, bucket control union 605, arm control union 610, and turret rotation control union 613 can be adjusted proportionally with the pilot pressure, so as to achieve the proportional control of the actuator; The pilot hydraulic handle 21 is used to control the boom and bucket actions. This handle can move in four directions: forward, backward, left, and right, corresponding to four proportional actions. The pressure signal output by the handle is proportional to its moving angle. Therefore, the pressure in the pilot chamber of the corresponding spool in the main control valve 6 can also be adjusted proportionally, realizing the proportional control of the spool opening and the actuator speed. The same applies to the pilot hydraulic handle 22; See Figure 2 , taking the two actions of boom lowering and gripper left rotation as examples, to illustrate the basic working principle of the pilot oil circuit: First, after the pilot main solenoid valve 2007 is energized, it switches to the right position. The pilot gear pump 18 sucks oil from the fuel tank 1 through the oil suction filter three 17. Its output pressure oil flows through the high-pressure filter three 19, pilot filter 2010, check valve one 2009 in sequence, and then enters the gripper left rotation solenoid valve 2001 or outputs a pressure signal from the pilot hydraulic handle. The pilot main relief valve 2008 set in the system is used to limit the pilot system pressure and play a protective role. When the gripper left rotation solenoid valve 2001 is energized, the pilot chamber of the gripper rotation control union 608 in the main control valve 6 receives a hydraulic signal, driving the gripper rotation motor 11 to achieve left rotation. At the same time, operate the pilot hydraulic handle to move forward, and the corresponding pilot chamber in the boom control union 602 receives a proportional pressure signal, thereby controlling the boom cylinder 7 to achieve the lowering action.

[0025] It should be understood that the above specific embodiments of the present invention are only for illustrative or explanatory purposes of the principles of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all variations and modifications that fall within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A palm car hydraulic control system, which includes a main control system and a pilot control system, characterized in that: The main control system includes a main control valve (6) and a gear pump 1 (3) and a gear pump 2 (15) connected to the oil tank (1). The main control valve (6) is provided with two left and right circuits. The gear pump 1 (3) and the gear pump 2 (15) are respectively connected to the two circuits for oil supply. The main control valve (6) is provided with a plurality of control links, namely a boom control link (602), a bucket control link (605), a gripper loosening control link (606), a carriage lifting control link (607), and a gripper swing control link (608). ), a boom control link (610) and a turret swing control link (613), wherein the boom control link (602), the bucket control link (605) and the gripper tightness control link (606) are all arranged in the left circuit, and the remaining control links are arranged in the right circuit, the left circuit is provided with a left-circuit overflow valve (601), and the right circuit is provided with a right-circuit overflow valve (614); each control link is connected to the working chamber of the corresponding actuator, and a radiator (5) is arranged on the oil return line connected to the control link on the main control valve (6); The pilot control system comprises a pilot hydraulic handle 1 (21), a pilot hydraulic handle 2 (22), a pilot control valve group (20) and a pilot gear pump (18); the pressure output end of the pilot gear pump (18) is connected to the pilot control valve group (20); the pilot hydraulic handle 1 (21) and the pilot hydraulic handle 2 (22) are both connected to the hydraulic circuit in the pilot control valve group (20); a pilot main solenoid valve (2007) and a plurality of solenoid reversing valves are provided in the hydraulic circuit in the pilot control valve group (20); the pilot hydraulic handle 1 (21), the pilot hydraulic handle 2 (22) and the plurality of solenoid valves are all connected to the rear of the pilot main solenoid valve (2007); and the hydraulic signal output by the pilot control valve group (20) is connected to the pilot chambers of the respective proportional valve cores of the main control valve (6).

2. A palm cart hydraulic control system according to claim 1, characterized in that: The boom control link (602) is connected to a boom cylinder (7), the bucket control link (605) is connected to a bucket cylinder (8), the gripper tension control link (606) is connected to a gripper tension cylinder (9), the carriage lifting control link (607) is connected to a carriage lifting cylinder (10), the gripper rotation control link (608) is connected to a gripper rotation motor (11), the arm control link (610) is connected to an arm cylinder (12), and the turret rotation control link (613) is connected to a turret rotation cylinder (13).

3. A palm cart hydraulic control system according to claim 1, characterized in that: The multiple electromagnetic reversing valves are, in order, a gripper left-rotation solenoid valve (2001), a gripper right-rotation solenoid valve (2002), a carriage lowering solenoid valve (2003), a carriage raising solenoid valve (2004), a gripper tightening solenoid valve (2005), and a gripper loosening solenoid valve (2006).

4. A palm cart hydraulic control system according to claim 1, characterized in that: A pilot filter (2010) is provided at the oil inlet port of the pilot control valve group (20), and a pilot main overflow valve (2008) is provided between the outlet of the pilot filter (2010) and the oil return path in the pilot control valve group (20).

5. A palm cart hydraulic control system according to claim 4, characterized in that: The rear end of the pilot filter (2010) is connected to a one-way valve 1 (2009), and the pilot filter (2010) is connected in parallel to a one-way valve 2 (2011) for providing bypass protection.

6. A palm cart hydraulic control system according to claim 2, characterized in that: In the left circuit, the two oil circuits connected to the boom cylinder (7) are respectively provided with a buffer valve 1 (603) and a buffer valve 2 (604); in the right circuit, the two oil circuits connected to the turret swing cylinder (13) are respectively provided with a buffer valve 4 (611) and a buffer valve 5 (612), and the return oil circuit of the boom cylinder (12) is provided with a buffer valve 3 (609).

7. A palm cart hydraulic control system according to claim 1, characterized in that: An oil suction filter (2) is connected between the gear pump 1 (3) and the oil tank (1), an oil suction filter 2 (16) is connected between the gear pump 2 (15) and the oil tank (1), and an oil suction filter 3 (17) is provided between the pilot gear pump (18) and the oil tank (1); a high-pressure filter 1 (4) is provided at the rear of the gear pump 1 (3), a high-pressure filter 2 (14) is connected at the rear of the gear pump 2 (15), and a high-pressure filter 3 (19) is connected at the rear end of the pilot gear pump (18).

Images