Excavator bucket rod contraction mechanism

Abstract

The utility model discloses an excavator bucket rod contraction mechanism, which belongs to the technical field of excavators and comprises a bucket rod control valve, and a valve port on the lower portion of the bucket rod control valve is connected with an oil way system. A valve port in the upper portion of the bucket rod control valve is connected with the pilot pressure speed regulating valve, and the pilot pressure speed regulating valve is connected with the bucket rod oil cylinder. A bucket rod approaching induction plate is arranged on a hydraulic rod of the bucket rod oil cylinder; one end of the upper part of the bucket rod oil cylinder is provided with a bucket rod inward-retracting contact head, and the other end is provided with a bucket rod outward-extending contact head; the bucket rod inward-retracting contact head and the bucket rod outward-extending contact head are connected with the bucket rod proximity switch, the bucket rod proximity switch is connected with the relay, the relay is electrically connected with the electric proportional pressure reducing valve, and the electric proportional pressure reducing valve is connected with the pilot pressure speed regulating valve in parallel. The low-speed operation of the bucket rod can be realized, the fine operation of the excavator bucket is facilitated, and the overall operability is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of excavators, and particularly relates to a boom retraction mechanism of an excavator. Background Technique

[0002] The statements in this part only provide background technical information related to the utility model, and do not necessarily constitute prior art.

[0003] An excavator is a commonly used construction machinery in the engineering operation process, and the working process of the excavator is mostly controlled by an oil circuit. The working arm of the existing excavator is mainly provided with a boom cylinder, a stick cylinder and a bucket cylinder, and the excavator is controlled to perform engineering operations through the combined action of the boom cylinder, the stick cylinder and the bucket cylinder.

[0004] However, in the use process, different users have different requirements for the operability of the excavator. Some users are used to the original fast operation of the excavator for work, and some users are used to the excavator with a slower speed. The existing excavator cannot adjust the action to be slow after the installation of the oil circuit hydraulic system, so it is difficult to achieve the purpose of meeting the needs of users. Especially during fine operations, a fast speed cannot guarantee the accuracy of the bucket position. Therefore, a slow operation is required to meet the accuracy of the bucket position, which is convenient for the land leveling operation of the excavator. Summary of the Utility Model

[0005] Aiming at the above problems, the utility model provides a boom retraction mechanism of an excavator, which can realize the slow operation of the boom, facilitate the fine operation of the bucket of the excavator, and improve the overall operability.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] A boom retraction mechanism of an excavator includes a stick control valve, the valve port at the lower part of the stick control valve is connected to the oil circuit system; the valve port at the upper part of the stick control valve is connected to a pilot pressure speed regulating valve, and the pilot pressure speed regulating valve is connected to the stick cylinder; a stick proximity induction plate is arranged on the hydraulic rod of the stick cylinder; at one end of the upper part of the stick cylinder, a stick retraction contact head is arranged, and at the other end, a stick extension contact head is arranged; the stick retraction contact head and the stick extension contact head are connected to a stick proximity switch, the stick proximity switch is connected to a relay, the relay is electrically connected to an electro-hydraulic proportional pressure reducing valve, and the electro-hydraulic proportional pressure reducing valve is connected in parallel with the pilot pressure speed regulating valve.

[0008] Further, the pilot pressure speed regulating valve includes a first pilot pressure speed regulating valve and a second pilot pressure speed regulating valve; one valve port at the upper part of the stick control valve is connected to one end of the first pilot pressure speed regulating valve, and the other valve port is connected to one end of the second pilot pressure speed regulating valve;

[0009] Further, the other end of the first pilot pressure speed control valve is connected to one end of the lower part of the bucket arm cylinder, and the other end of the second pilot pressure speed control valve is connected to the other end of the lower part of the bucket arm cylinder.

[0010] Further, the bucket arm proximity switches include a bucket arm retraction proximity switch and a bucket arm extension proximity switch. The bucket arm retraction contact head is connected to the bucket arm retraction proximity switch, and the bucket arm extension contact head is connected to the bucket arm extension proximity switch.

[0011] Further, the bucket arm retraction proximity switch is connected to a first relay, and the bucket arm extension proximity switch is connected to a second relay; the upper ends of the bucket arm retraction proximity switch and the bucket arm extension proximity switch are connected by a first wire, and the lower ends are connected by a second wire. The first wire is connected to the power supply line, and the second wire is connected to the ground wire.

[0012] Further, the first relay includes a switch, a coil, and a diode. The diode is connected in parallel with the coil. One end of the coil is connected to the bucket arm proximity switch, and the other end of the coil is connected to the power supply line; one end of the switch is connected to the power supply line, and the other end of the switch is connected to an electro-hydraulic proportional pressure reducing valve; the structures of the first relay and the second relay are the same.

[0013] Further, the electro-hydraulic proportional pressure reducing valves include a first electro-hydraulic proportional pressure reducing valve and a second electro-hydraulic proportional pressure reducing valve. The upper end of the first electro-hydraulic proportional pressure reducing valve is connected to the first relay, and the lower end of the first electro-hydraulic proportional pressure reducing valve is connected to the valve port of the bucket arm control valve; the upper end of the second electro-hydraulic proportional pressure reducing valve is connected to the second relay, and the lower end of the second electro-hydraulic proportional pressure reducing valve is connected to the valve port of the bucket arm control valve.

[0014] Further, the first electro-hydraulic proportional pressure reducing valve and the second electro-hydraulic proportional pressure reducing valve are connected by a third wire, and the third wire is connected to the ground wire.

[0015] Further, the oil circuit system includes a hydraulic pump, an oil filter, a relief valve, and an oil tank. One end of the hydraulic pump is connected to the valve port of the bucket arm control valve, and the other end of the hydraulic pump is connected to one end of the oil filter.

[0016] Further, the other end of the oil filter is connected to the oil tank. One end of the relief valve is connected to the upper end of the oil pump, and the other end of the relief valve is connected to the oil tank.

[0017] Compared with the prior art, the advantages and positive effects of the present utility model are:

[0018] The utility model realizes slow operation of the stick by making the outer extension contact head and the inner retraction contact head on the stick cylinder contact with the stick proximity induction plate. After contact, the proximity switch senses that the hydraulic rod of the stick cylinder enters the speed regulation state, and the proximity switch disconnects to make the relay close, and the electro-hydraulic proportional pressure reducing valve is powered on. According to the inner retraction or outer extension state, oil is supplied to or discharged from the oil cavity of the stick cylinder, thereby reducing the valve port of the pilot pressure speed regulating valve and reducing the oil flow rate at the oil inlet of the hydraulic cylinder, and further slowing down the movement of the stick during outer extension or inner retraction, facilitating fine operation of the excavator bucket and improving the overall operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The attached drawings forming a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments and descriptions thereof of the present utility model are used to explain the present utility model and do not constitute an improper limitation to the present utility model.

[0020] Figure 1 is a schematic structural diagram of the fast and slow retraction mechanism of the stick of the excavator of the present utility model;

[0021] In the figure: 1, stick control valve; 2, oil circuit system; 201, overflow valve; 202, hydraulic pump; 203, oil filter; 204, fuel tank; 3, first pilot pressure speed regulating valve; 4, first electro-hydraulic proportional pressure reducing valve; 5, second pilot pressure speed regulating valve; 6, second electro-hydraulic proportional pressure reducing valve; 7, stick cylinder; 8, stick outer extension contact head; 9, stick proximity induction plate; 10, stick inner retraction contact head; 11, stick outer extension proximity switch; 12, stick inner retraction proximity switch; 13, first relay; 14, second relay; 15, power line; 16, ground wire; 17, switch; 18, coil; 19, diode; 20, first wire; 21, second wire; 22, third wire. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present utility model. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present utility model belongs.

[0023] When the excavator is operating, it can perform fine leveling. Lower the boom of the excavator slightly so that the stick is perpendicular to the ground, and the movement range of the stick is about 45 degrees. Open the bucket so that the bucket mouth is basically horizontal with the second arm. After the bucket touches the ground, retract the second arm and raise the boom to pull the soil backward; after finishing one shovel width, move the fuselage and complete the leveling in sequence. At this time, slow control of the stick is required to ensure the accurate final position of the bucket.

[0024] The following combines the attached drawings to describe the present utility model in detail. An excavator stick retraction mechanism disclosed in this embodiment is as Figure 1As shown in the figure, it includes a boom control valve 1. The valve port at the lower part of the boom control valve 1 is connected to an oil circuit system 2. The valve port at the upper part of the boom control valve 1 is connected to a pilot pressure speed regulating valve, and the pilot pressure speed regulating valve is connected to a boom cylinder 7. A boom proximity induction plate 9 is arranged on the hydraulic rod of the boom cylinder 7. At one end of the upper part of the boom cylinder 7, a boom retraction contact head 10 is arranged, and at the other end, a boom extension contact head 8 is arranged. The boom retraction contact head 10 and the boom extension contact head 8 are connected to a boom proximity switch, the boom proximity switch is connected to a relay, the relay is electrically connected to an electro-hydraulic proportional pressure reducing valve, and the electro-hydraulic proportional pressure reducing valve is connected in parallel with the pilot pressure speed regulating valve.

[0025] Through the extension contact head and the retraction contact head on the boom cylinder 7 contacting the boom proximity induction plate 9, after the contact, the proximity switch senses that the hydraulic rod of the boom cylinder 7 enters the speed regulation state, the proximity switch disconnects to make the relay close, the electro-hydraulic proportional pressure reducing valve gets electricity, and according to the retraction or extension state, it supplies oil or discharges oil to the oil cavity of the boom cylinder 7, thereby reducing the valve port of the pilot pressure speed regulating valve and reducing the oil flow at the oil inlet of the hydraulic cylinder, and further slowing down the boom during extension or retraction.

[0026] The pilot pressure speed regulating valve includes a first pilot pressure speed regulating valve 3 and a second pilot pressure speed regulating valve 5. One valve port at the upper part of the boom control valve 1 is connected to one end of the first pilot pressure speed regulating valve 3, and the other valve port is connected to one end of the second pilot pressure speed regulating valve 5. The other end of the first pilot pressure speed regulating valve 3 is connected to one end of the lower part of the boom cylinder 7, and the other end of the second pilot pressure speed regulating valve 5 is connected to the other end of the lower part of the boom cylinder 7.

[0027] The boom proximity switch includes a boom retraction proximity switch and a boom extension proximity switch 11. The boom retraction contact head 10 is connected to the boom retraction proximity switch 12, and the boom extension contact head 8 is connected to the boom extension proximity switch 11. In the retraction state, the boom retraction contact head 10 contacts the boom proximity induction plate 9, making the boom retraction proximity switch 12 disconnect. In the extension state, the boom extension contact head 8 contacts the boom proximity induction plate 9, making the boom extension proximity switch 11 disconnect. When the boom retraction proximity switch 12 or the boom extension proximity switch disconnects, the relay closes, and then the pressure reducing valve gets electricity for pressure reduction, thereby realizing the speed reduction of the boom during extension or retraction.

[0028] A relay is an electronic control device that has a control system (also known as the input circuit) and a controlled system (also known as the output circuit), and is usually applied to an automatic control circuit. The boom retraction proximity switch 12 is connected to the first relay 13, and the boom extension proximity switch 11 is connected to the second relay 14; the upper ends of the boom retraction proximity switch 12 and the boom extension proximity switch 11 are connected by a first wire 20, and the lower ends are connected by a second wire 21. The first wire 20 is connected to the power supply line 15, and the second wire 21 is connected to the ground wire 16. The first relay 13 includes a switch, a coil 18, and a diode 19. The diode 19 is connected in parallel with the coil 18. One end of the coil 18 is connected to the boom proximity switch, and the other end of the coil 18 is connected to the power supply line 15; one end of the switch 17 is connected to the power supply line 15, and the other end of the switch 17 is connected to the electro-hydraulic proportional relief valve. The first relay 13 and the second relay 14 have the same structure. The opening and closing states of the first electro-hydraulic proportional relief valve 4 or the second electro-hydraulic proportional relief valve 6 are controlled by the first relay 13 and the second relay 14, thereby achieving pressure reduction.

[0029] The electro-hydraulic proportional relief valve includes a first electro-hydraulic proportional relief valve 4 and a second electro-hydraulic proportional relief valve 6. The upper end of the first electro-hydraulic proportional relief valve 4 is connected to the first relay 13, and the lower end of the first electro-hydraulic proportional relief valve 4 is connected to the valve port of the boom control valve 1; the upper end of the second electro-hydraulic proportional relief valve 6 is connected to the second relay 14, and the lower end of the second electro-hydraulic proportional relief valve 6 is connected to the valve port of the boom control valve 1. The first electro-hydraulic proportional relief valve 4 and the second electro-hydraulic proportional relief valve 6 are connected by a third wire 22, and the third wire 22 is connected to the ground wire 16.

[0030] The oil circuit system 2 includes a hydraulic pump 202, an oil filter 203, a relief valve 201, and an oil tank 204. One end of the hydraulic pump 202 is connected to the valve port of the boom control valve 1, and the other end of the hydraulic pump 202 is connected to one end of the oil filter 203. The other end of the oil filter 203 is connected to the oil tank 204. One end of the relief valve 201 is connected to the upper end of the oil pump, and the other end of the relief valve 201 is connected to the oil tank 204. The oil circuit system 2 is used to convey pressure oil into the boom control valve, thereby controlling the oil inlet or oil outlet state of the chamber of the boom cylinder 7, and further causing the hydraulic rod to retract or extend to drive the boom to retract or extend.

[0031] Usage method:

[0032] At the positions where the telescopic hydraulic cylinder is close to the maximum stroke and the minimum stroke, Hall-type proximity switches that need speed regulation recognition are installed, namely the boom extension contact switch and the boom retraction proximity switch 12. Through the boom retraction contact head 10 or the boom extension contact head 8 contacting the boom proximity induction plate 9, the boom extension contact switch or the boom retraction contact switch is opened or closed, and then the first relay 13 or the second relay 14 is opened, and then the first electro-hydraulic proportional relief valve 4 or the second electro-hydraulic proportional relief valve 6 is opened for speed regulation, that is, the retraction or extension state of the boom is decelerated according to the contact situation between the boom proximity induction plate 9 fixed on the hydraulic rod and the contact head;

[0033] When the stroke of the boom cylinder 7 is in the middle position, the proximity switch sends a signal to make the two normally closed proximity relays in the off state. At this time, the boom runs at a normal speed;

[0034] The slow operation of the boom is divided into two states, one is the retraction state and the other is the extension state; the boom cylinder 7 is divided into two chambers, and the end where the hydraulic rod is located is the large chamber end, and the other end is the small chamber end; the boom control valve 1 is a three-position four-way directional control valve with three valve positions;

[0035] When the boom extends outwards, the boom control valve 1 is in the left valve position, and the hydraulic oil enters from the large chamber end and flows out from the small chamber end. When the boom extension proximity switch 11 senses that the hydraulic rod enters the speed regulation stroke, the boom extension proximity switch 11 disconnects, making the second relay 14 close, making the second electro-hydraulic proportional relief valve 6 energized, filling the second pilot pressure speed regulating valve 5 at the oil inlet of the large chamber end, reducing the valve port of the second pilot pressure speed regulating valve 5, reducing the oil inlet flow rate of the boom cylinder 7, and slowing down the extension movement of the boom;

[0036] When the boom continues to retract inwards, the boom control valve 1 is in the right valve position, and the hydraulic oil enters from the small chamber end and flows out from the large chamber end. When the boom retraction proximity switch 12 senses that the hydraulic rod enters the speed regulation stroke, the boom retraction proximity switch 12 disconnects, making the first relay 13 close, making the first electro-hydraulic proportional relief valve 4 energized, filling the first pilot speed regulating valve at the oil inlet of the small chamber end, reducing the valve port of the first pilot speed regulating valve, reducing the oil inlet flow rate of the boom cylinder 7, and slowing down the retraction movement of the boom.

[0037] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. An excavator boom retraction mechanism, characterized in that: It includes a boom control valve, wherein the valve port at the lower part of the boom control valve is connected to the oil circuit system; the valve port at the upper part of the boom control valve is connected to the pilot pressure speed regulating valve, and the pilot pressure speed regulating valve is connected to the boom cylinder; a boom proximity sensing plate is arranged on the hydraulic rod of the boom cylinder; a boom inward contact head is arranged at one end of the upper part of the boom cylinder, and a boom outward contact head is arranged at the other end; the boom inward contact head and the boom outward contact head are connected to a boom proximity switch, and the boom proximity switch is connected to a relay, and the relay is electrically connected to an electric proportional pressure reducing valve, and the electric proportional pressure reducing valve is connected in parallel with the pilot pressure speed regulating valve.

2. The excavator boom retraction mechanism according to claim 1, characterized in that: The pilot pressure speed regulating valve includes a first pilot pressure speed regulating valve and a second pilot pressure speed regulating valve; a valve port on the upper part of the boom control valve is connected to one end of the first pilot pressure speed regulating valve, and the other valve port is connected to one end of the second pilot pressure speed regulating valve.

3. The excavator boom retraction mechanism according to claim 2, characterized in that: The other end of the first pilot pressure speed regulating valve is connected to one end of the lower part of the boom cylinder, and the other end of the second pilot pressure speed regulating valve is connected to the other end of the lower part of the boom cylinder.

4. The excavator boom retraction mechanism according to claim 1, characterized in that: The arm proximity switch includes an arm retracting proximity switch and an arm extending proximity switch. The arm retracting contact head is connected to the arm retracting proximity switch, and the arm extending contact head is connected to the arm extending proximity switch.

5. The excavator boom retraction mechanism according to claim 4, characterized in that: The boom retraction proximity switch is connected to the first relay, and the boom extension proximity switch is connected to the second relay; the upper ends of the boom retraction proximity switch and the boom extension proximity switch are connected by a first wire, and the lower ends are connected by a second wire, the first wire is connected to the power line, and the second wire is connected to the ground wire.

6. The excavator boom retraction mechanism according to claim 5, characterized in that: The first relay includes a switch, a coil and a diode, the diode is connected in parallel with the coil, one end of the coil is connected to the boom proximity switch, and the other end of the coil is connected to the power cord; one end of the switch is connected to the power cord, and the other end of the switch is connected to the electric proportional pressure reducing valve; the first relay and the second relay have the same structure.

7. The excavator boom retraction mechanism according to claim 6, characterized in that: The electric proportional pressure reducing valve includes a first electric proportional pressure reducing valve and a second electric proportional pressure reducing valve, the upper end of the first electric proportional pressure reducing valve is connected to the first relay, and the lower end of the first electric proportional pressure reducing valve is connected to the valve port of the boom control valve; the upper end of the second electric proportional pressure reducing valve is connected to the second relay, and the lower end of the second electric proportional pressure reducing valve is connected to the valve port of the boom control valve.

8. The excavator boom retracting mechanism according to claim 7, characterized in that: The first electric proportional pressure reducing valve is connected to the second electric proportional pressure reducing valve via a third wire, and the third wire is connected to a ground wire.

9. The excavator boom retraction mechanism according to claim 1, characterized in that: The oil circuit system includes a hydraulic pump, an oil filter, an overflow valve and an oil tank. One end of the hydraulic pump is connected to the valve port of the boom control valve, and the other end of the hydraulic pump is connected to one end of the oil filter.

10. The excavator boom retracting mechanism according to claim 9, characterized in that: The other end of the oil filter is connected to the oil tank, one end of the overflow valve is connected to the upper end of the oil pump, and the other end of the overflow valve is connected to the oil tank.

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