CN217327880U

CN217327880U - Hydraulic system for load sensing and pilot pressure control of drilling machine

Info

Publication number: CN217327880U
Application number: CN202220975319.6U
Authority: CN
Inventors: 陈党伟; 赵彤凯; 卢政彤; 李海臣; 宋忠兴; 宋世伟
Original assignee: Gltech Co ltd
Current assignee: Gltech Co ltd
Priority date: 2022-04-25
Filing date: 2022-04-25
Publication date: 2022-08-30
Anticipated expiration: 2032-04-25

Abstract

The utility model relates to a hydraulic system that is used for sensitive and guide's pressure control of load of rig. The hydraulic control system comprises a load sensitive variable pump, an oil supply control valve, a hydraulic motor, a pilot oil path, a shuttle valve, a load feedback oil path and a pilot feedback oil path, wherein an oil outlet of the load sensitive variable pump is connected with an oil inlet of the hydraulic motor through the oil supply control valve, and the oil outlet of the load sensitive variable pump provides pilot pressure control for the hydraulic motor through the pilot oil path so as to adjust the displacement of the hydraulic motor; the pilot pressure of the pilot oil circuit is fed back to the shuttle valve by the pilot feedback oil circuit, the load pressure of the hydraulic motor is fed back to the shuttle valve by the load feedback oil circuit, and the larger pressure is output and fed back to the load sensitive variable pump after being compared by the shuttle valve. The utility model discloses a this kind of hydraulic system carries out the feedback of guide's pressure when utilizing guide's pressure control hydraulic motor discharge capacity, and it is fast to adjust response speed, and the degree of accuracy is higher, has greatly made things convenient for hydraulic motor's output to adjust.

Description

Hydraulic system for load sensing and pilot pressure control of drilling machine

Technical Field

The utility model relates to an engineering machine tool execute component's hydraulic control technical field, concretely relates to a hydraulic system that is used for the sensitive and guide's pressure control of load of rig.

Background

In the hydraulic system of the coal mine underground drill rig in the prior art, a load feedback control mode is usually adopted to change the hydraulic oil flow of a hydraulic motor so as to adjust the output power of the hydraulic motor, for example, a full-hydraulic multi-arm umbrella drill with load sensitive control disclosed in chinese patent with the publication number of CN105156028B includes a load sensitive pump, a load sensitive multi-way directional valve, a hydraulic motor and other mechanisms, and the oil outlet of the load sensitive pump is connected with the hydraulic motor through the load sensitive multi-way directional valve so as to output hydraulic oil to the hydraulic motor. The flow direction and flow rate of the hydraulic oil can be adjusted through the load-sensitive multi-way reversing valve, and the hydraulic motor feeds back load pressure to the load-sensitive pump through a feedback oil circuit (LS pipeline) of the load-sensitive multi-way reversing valve when in work so as to control the output pressure adjustment of the load-sensitive variable pump. The hydraulic system controls the output power change of the hydraulic motor by adjusting the flow of an oil inlet of the hydraulic motor.

For another example, the chinese patent with application publication No. CN113404735A discloses a load-sensitive hydraulic system for tilt angle adjustment of a drilling machine, which includes a hydraulic pump, a multi-way valve, and a hydraulic motor that are sequentially connected, the hydraulic pump is connected to the hydraulic motor through the multi-way valve to supply hydraulic oil to the hydraulic motor, a sequence valve and a throttle valve are further disposed on an oil return path of the hydraulic motor, a back pressure of the oil return path can be set by setting an opening pressure of the sequence valve, and an oil return port flow of the hydraulic motor can be adjusted by controlling the throttle valve, thereby adjusting a rotation speed of the hydraulic motor. Such a hydraulic system controls the output power change of the hydraulic motor by adjusting the displacement of the hydraulic motor.

However, in the load-sensitive control method, when the outlet pressure of the load-sensitive pump is controlled to change according to the fed-back load pressure, since the actual load pressure of the hydraulic motor needs a certain time to be adjusted to a set value after the opening of the valve and the output pressure of the hydraulic pump are adjusted, a feedback adjustment process has a certain hysteresis, the reaction time is long, and the adjustment accuracy is poor.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a hydraulic system that is used for the sensitive and guide's pressure control of load of rig for solve current rig hydraulic control system response speed slow, adjust the poor problem of accuracy.

In order to achieve the above object, the present invention provides a hydraulic system for load sensing and pilot pressure control of a drilling machine, which adopts the following technical solution: the hydraulic control system comprises a load sensitive variable pump, an oil supply control valve and a hydraulic motor, wherein the load sensitive variable pump is provided with an oil outlet and a pump feedback oil outlet, the oil outlet is connected with an oil inlet of the hydraulic motor through the oil supply control valve, the pump feedback oil outlet is connected with a pump feedback oil path, the pump feedback oil path is used for feeding back and adjusting hydraulic pressure to the load sensitive variable pump, the hydraulic motor comprises a displacement control valve, the displacement control valve is used for controlling the hydraulic oil displacement of the oil outlet of the hydraulic motor, the displacement control valve comprises a pilot control oil cylinder, and the pilot control oil cylinder is used for adjusting the opening of the displacement control valve; the hydraulic motor displacement control system is characterized by further comprising a pilot oil way, wherein one end of the pilot oil way is communicated with the oil outlet of the pump, the other end of the pilot oil way is communicated with the pilot control oil cylinder, a pilot on-off valve and a pressure reducing valve are arranged on the pilot oil way, and the pressure reducing valve is used for adjusting the pilot pressure of hydraulic oil output to the pilot control oil cylinder from the pilot oil way so as to control the displacement control valve to adjust the displacement of the hydraulic motor through the pilot control oil cylinder; the hydraulic control system further comprises a shuttle valve, a load feedback oil path and a pilot feedback oil path, one end of the pilot feedback oil path is communicated with the pilot oil path through a one-way valve, the other end of the pilot feedback oil path is communicated with the pump feedback oil path through the shuttle valve and used for feeding back pilot hydraulic pressure output by the pilot oil path, one end of the load feedback oil path is communicated with the hydraulic motor, the other end of the load feedback oil path is also communicated with the pump feedback oil path through the shuttle valve and used for feeding back load hydraulic pressure of the hydraulic motor, and the shuttle valve is used for comparing the pilot hydraulic pressure fed back by the pilot feedback oil path with the load hydraulic pressure fed back by the load feedback oil path and outputting hydraulic oil with the highest pressure to the pump feedback oil path.

The beneficial effects are that: when the flow of hydraulic oil introduced into the hydraulic motor by the load-sensitive variable pump is controlled by the oil supply control valve, pilot pressure with adjustable size is introduced into the pilot control oil cylinder by the pilot oil circuit, the displacement of the hydraulic motor is adjusted by the displacement control valve controlled by the pilot control oil cylinder, the rotation speed of the hydraulic motor is convenient to adjust, and the interference with the working and adjusting processes of a main oil circuit can be avoided, so that the control requirement of the hydraulic oil circuit under various working conditions is met; and the pilot pressure is fed back in real time through the feedback oil path while the pilot pressure is changed by the pilot oil path, and is compared with the actual load pressure fed back by the hydraulic motor, and the larger pressure is fed back to the load-sensitive variable pump so as to control the change of the oil outlet pressure of the load-sensitive variable pump, so that the response speed is high, and the accurate adjustment of hydraulic pressure is facilitated.

Preferably, the number of the hydraulic motors is more than two, the load feedback oil paths are arranged in one-to-one correspondence with the hydraulic motors, the shuttle valves comprise more than two shuttle valves which are connected in series in a grading manner, an output port of the final stage shuttle valve is communicated with the pump feedback oil path, and two input ports of the primary stage shuttle valve are respectively communicated with the two load feedback oil paths or one load feedback oil path and the pilot feedback oil path; in two adjacent upper and lower shuttle valves, one input port of the lower shuttle valve is communicated with the output port of the upper shuttle valve, and the other input port of the lower shuttle valve is communicated with a load feedback oil path or a pilot feedback oil path

Preferably, the shuttle valve includes a first shuttle valve and a second shuttle valve, the hydraulic motor includes a first hydraulic motor and a second hydraulic motor, the load feedback oil path includes a first load feedback oil path and a second load feedback oil path respectively communicated with the first hydraulic motor and the second hydraulic motor, the pilot feedback oil path and the first load feedback oil path are respectively communicated with two input ports of the first shuttle valve, an output port of the first shuttle valve and the second load feedback oil path are respectively communicated with two input ports of the second shuttle valve, and an output port of the second shuttle valve is communicated with the pump feedback oil path.

Preferably, the oil supply control valve is a load-sensitive proportional valve, an oil inlet of the load-sensitive proportional valve is communicated with an oil outlet of the pump, and an oil outlet of the load-sensitive proportional valve is communicated with the hydraulic motor.

Preferably, the pressure reducing valve is connected with a first oil return path and a second oil return path, and is connected with the oil tank through the first oil return path and the second oil return path respectively, and the second oil return path is provided with an overflow valve for limiting the maximum value of the pilot pressure.

The beneficial effects are that: the overflow valve is arranged to effectively limit the maximum value of pilot pressure adjustment, so that the displacement adjustment threshold value of the hydraulic motor is guaranteed, and the hydraulic motor is prevented from being damaged due to overlarge pilot pressure.

Preferably, a speed regulating valve is further arranged on the pilot oil path and used for changing the flow of the hydraulic oil of the pilot oil path.

The beneficial effects are that: the speed regulating valve is arranged to change the hydraulic oil flow of the pilot oil way, so that the overflow flow of the overflow valve is limited to a lower value, and the energy loss of the system is reduced.

Preferably, the pilot feedback oil path is connected with a third oil return oil path, the third oil return oil path is provided with a damping element, and the pilot feedback oil path is connected with the oil tank through the third oil return oil path and the damping element.

The beneficial effects are that: the hydraulic oil returns to the hydraulic oil tank through the damping element to play an unloading role so as to ensure the stability of the pilot oil circuit and the pilot feedback oil circuit and ensure the working performance of the hydraulic system.

Drawings

Fig. 1 is a schematic structural diagram of a pilot pressure control system according to the present invention.

In the figure: 1. a load-sensitive variable displacement pump; 2. a load-sensitive proportional valve; 3. a first hydraulic motor; 4. a second hydraulic motor; 5. a displacement control valve; 6. a pilot control cylinder; 7. a first load feedback loop; 8. a second load feedback loop; 9. a first shuttle valve; 10. a second shuttle valve; 11. a speed regulating valve; 12. a pilot on-off valve; 13. an overflow valve; 14. a one-way valve; 15. a pressure reducing valve; 16. a damping element; 17. a pump feedback oil path; 18. a pilot feedback oil path; 19. a first oil return path; 20. a second oil return path; 21. and a third oil return path.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clear, the present invention is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention, i.e., the described embodiments are only some, but not all embodiments of the invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by the person skilled in the art without creative work belong to the protection scope of the present invention.

It is noted that relational terms such as "first" and "second," and the like, which may be present, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, terms such as "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …," or the like, does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The features and properties of the present invention are described in further detail below with reference to examples.

The utility model discloses a hydraulic system's for load is sensitive and guide's pressure control of rig concrete embodiment: as shown in fig. 1, the hydraulic system of the present embodiment mainly includes a load-sensitive variable displacement pump 1, a load-sensitive proportional valve 2, a hydraulic motor, a pilot oil path, an overflow valve 13, and a damping element 16. The load-sensitive variable pump 1 is provided with a pump outlet (port B) and a pump feedback outlet (port X), the pump feedback outlet is connected with a pump feedback oil path 17, and the pump feedback oil path 17 is used for feeding back and adjusting hydraulic pressure to the load-sensitive variable pump 1. An oil outlet of the pump is connected with an oil inlet (P port) of the load sensitive proportional valve 2, an oil outlet of the load sensitive proportional valve 2 is connected with an oil inlet of the hydraulic motor, the load sensitive variable pump 1 supplies driving hydraulic oil to the hydraulic motor through the load sensitive proportional valve 2, and the load sensitive proportional valve 2 is used for adjusting the flow of the hydraulic oil input into the hydraulic motor by the load sensitive variable pump 1.

The two hydraulic motors are arranged, oil outlets of the two hydraulic motors are provided with displacement control valves 5, each displacement control valve 5 comprises a pilot control oil cylinder 6, and the opening degree of each displacement control valve 5 is controlled through the pilot control oil cylinder 6, so that the displacement of each hydraulic motor is adjusted. The oil outlet of the pump of the load sensitive variable pump 1 is communicated with the pilot control oil cylinder 6 through a pilot oil path, a speed regulating valve 11, a pilot on-off valve 12 and a pressure reducing valve 15 are sequentially arranged on the pilot oil path, the speed regulating valve 11 is connected with the oil outlet of the pump of the load sensitive variable pump 1, the pressure reducing valve 15 is respectively connected with the pilot control oil cylinders 6 of the two hydraulic motors, the pressure reducing valve 15 is used for adjusting the pilot pressure of the pilot oil path output hydraulic oil, the pilot hydraulic oil is output to the pilot control oil cylinder 6 through the pilot oil path, the piston of the pilot control oil cylinder 6 is pushed to move, the opening size of the displacement control valve 5 is adjusted, the displacement of the hydraulic motors is adjusted, and further the rotating speed of the motors is controlled.

The hydraulic system of the present embodiment further includes a pilot feedback oil passage 18, a load feedback oil passage, and a shuttle valve. One end of a pilot feedback oil path 18 is communicated with the pilot oil path through a one-way valve 14, the other end of the pilot feedback oil path is communicated with the pump feedback oil path 17 through a shuttle valve and is used for feeding back pilot hydraulic pressure output by the pilot oil path, one end of a load feedback oil path is communicated with a hydraulic motor, the other end of the load feedback oil path is also communicated with the pump feedback oil path 17 through the shuttle valve and is used for feeding back load hydraulic pressure of the hydraulic motor, and the shuttle valve is used for comparing the pilot hydraulic pressure fed back by the pilot feedback oil path 18 with the load hydraulic pressure fed back by the load feedback oil path and outputting the hydraulic oil with the highest pressure to the pump feedback oil path 17.

Specifically, the two hydraulic motors are a first hydraulic motor 3 and a second hydraulic motor 4 respectively, correspondingly, the load feedback oil path includes a first load feedback oil path and a second load feedback oil path, which are respectively communicated with the first hydraulic motor 3 and the second hydraulic motor 4, and the shuttle valve includes a first shuttle valve 9 and a second shuttle valve 10. One end of the pilot feedback oil path 18 is connected to the pressure reducing valve 15 via the check valve 14, and the other end is connected to one input port of the first shuttle valve 9, and feeds the pilot oil pressure output from the pilot oil path back to the first shuttle valve 9. One end of the first load feedback oil path is connected with the first hydraulic motor 3, and the other end of the first load feedback oil path is connected with the other input port of the first shuttle valve 9, so that the load hydraulic pressure of the first hydraulic motor 3 is fed back to the first shuttle valve 9. The pilot hydraulic pressure fed back from the pilot feedback oil passage 18 is compared with the load hydraulic pressure fed back from the first load feedback circuit 7 in the first shuttle valve 9, wherein the hydraulic pressure of a higher pressure is output from the output port of the first shuttle valve 9 to one input port of the second shuttle valve 10. One end of the second load feedback loop 8 is connected with the second hydraulic motor 4, the other end of the second load feedback loop is connected with the other input port of the second shuttle valve 10, the load hydraulic pressure of the second hydraulic motor 4 is fed back into the second shuttle valve 10 and is compared with the higher pressure hydraulic pressure output by the first shuttle valve 9, the output port of the second shuttle valve 10 is communicated with the pump feedback oil path 17, the compared hydraulic pressure with the highest pressure is used as the adjusting hydraulic pressure and is fed back to the load sensitive variable pump 1 through the pump feedback oil path 17 and the pump feedback oil port, so that the hydraulic feedback adjustment of the load sensitive variable pump 1 is realized, and the output power of the load sensitive variable pump 1 is adjusted.

In addition, the pressure reducing valve 15 in the hydraulic system of the present embodiment is connected to a first oil return path 19 and a second oil return path 20, the pressure reducing valve 15 is connected to the oil tank through the first oil return path 19 and the second oil return path 20, respectively, wherein the first oil return path 19 passes through the pilot on-off valve 12 and is in a normally open state, and the second oil return path 20 is provided with the relief valve 13 for limiting the maximum value of the pilot pressure. Similarly, the pilot feedback oil path 18 is connected with a third oil return path 21, one end of the third oil return path 21 is communicated with the one-way valve 14, the other end of the third oil return path 21 is communicated with the oil tank, the third oil return path 21 is further provided with a damping element 16, the pilot feedback oil path 18 is connected with the oil tank through the third oil return path 21 and the damping element 16, and the damping element 16 plays an unloading role for hydraulic oil on the third oil return path 21 so as to ensure the stability of the third oil return path 21.

The utility model discloses a hydraulic system of above-mentioned embodiment is at the operation in-process, and the sensitive variable displacement pump of load 1 starts the back, follows the delivery port output hydraulic oil of pump, and hydraulic oil gets into two hydraulic motor's execution chamber respectively through the sensitive proportional valve 2 of load all the way, can adjust the hydraulic oil flow that lets in two hydraulic motor through the sensitive proportional valve 2 of load to control hydraulic motor's rotational speed. The other path of hydraulic oil enters the pilot control oil cylinder 6 through a speed regulating valve 11, a pilot on-off valve 12 and a pressure reducing valve 15 on the pilot oil path in sequence, the pressure reducing valve 15 is used for regulating the pilot pressure of the hydraulic oil output to the pilot control oil cylinder 6, the speed regulating valve 11 is used for regulating the flow of the hydraulic oil of the pilot oil path and limiting the overflow flow of an overflow valve 13 connected with the pressure reducing valve 15 to a lower value so as to reduce the energy loss of the system, and the pilot on-off valve 12 is used for controlling the on-off of the pilot oil path. After hydraulic oil enters the pilot control oil cylinder 6 through the pilot oil way, the piston of the pilot control oil cylinder 6 is pushed to move, a discharge capacity control valve 5 is arranged at an oil outlet of the hydraulic motor, and the piston of the pilot control oil cylinder 6 moves to change the opening size of the discharge capacity control valve 5, so that the discharge capacity of the hydraulic motor is changed. That is, the pilot hydraulic pressure output by the pilot oil path is adjusted by the pressure reducing valve 15 to change the piston movement displacement of the pilot control oil cylinder 6, and the opening size of the displacement control valve 5 is controlled, so that the functions of adjusting the rotating speed and the output power of the hydraulic motor are achieved. Meanwhile, the pilot hydraulic pressure output by the pilot oil line is input into the shuttle valve by the pilot feedback oil line 18, the load hydraulic pressure of the corresponding hydraulic motor is also input into the shuttle valve by the load feedback oil line, and after comparison by the shuttle valve, the hydraulic pressure with the highest pressure is fed back into the load sensitive variable displacement pump 1 as the regulating hydraulic pressure by the pump feedback oil line 17 and the pump feedback oil port, so that the output power of the load sensitive variable displacement pump 1 is regulated.

Of course, the present invention is not limited to the above-described embodiments, but also provides several other embodiments of the hydraulic system for load sensing and pilot pressure control of a drilling machine based on the design concept of the present invention, specifically as follows:

in other embodiments of a load sensitive and pilot pressure controlled hydraulic system for a drilling rig, different from the above described embodiments are: the load-sensitive proportional valve is not used as the oil supply control valve of the hydraulic motor, for example, the speed regulating valve and/or the electromagnetic directional valve is used as the oil supply control valve of the hydraulic motor, and the oil supply flow of the hydraulic motor can be adjusted.

In other embodiments of a load sensitive and pilot pressure controlled hydraulic system for a drilling rig, different from the above described embodiments are: the pressure reducing valve is provided with a pressure reducing valve, and the pressure reducing valve is communicated with an oil tank to realize oil return.

In other embodiments of a load sensitive and pilot pressure controlled hydraulic system for a drilling rig, different from the above described embodiments are: the pilot oil circuit may not be provided with a speed regulating valve, and the oil return circuit of the pilot feedback oil circuit may not be provided with a damping element, and further, the pilot feedback oil circuit may not be connected with the oil return circuit.

In other embodiments of a load sensitive and pilot pressure controlled hydraulic system for a drilling rig, different from the above described embodiments are: the number of the hydraulic motors can be one or more than two, the load feedback oil circuit and the shuttle valve are correspondingly provided with one or more than two, and the shuttle valve compares all feedback hydraulic pressures and feeds back the hydraulic output with the highest pressure to the load sensitive variable pump.

The above description is only for the preferred embodiment of the present invention, and the present invention is not limited thereto, the protection scope of the present invention is defined by the claims, and all structural changes equivalent to the contents of the description and drawings of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a hydraulic system for load is sensitive and guide's pressure control of rig, includes the sensitive variable pump of load (1), supplies oil control valve, hydraulic motor, the sensitive variable pump of load (1) has pump oil-out and pump feedback hydraulic fluid port, and pump oil-out connects hydraulic motor's oil inlet through supplying oil control valve, and pump feedback hydraulic fluid port is connected with pump feedback oil circuit, and pump feedback oil circuit is used for adjusting hydraulic pressure to the sensitive variable pump of load (1) feedback, its characterized in that:

the hydraulic motor comprises a displacement control valve (5), the displacement control valve (5) is used for controlling the hydraulic oil displacement of an oil outlet of the hydraulic motor, the displacement control valve (5) comprises a pilot control oil cylinder (6), and the pilot control oil cylinder (6) is used for adjusting the opening of the displacement control valve (5);

the hydraulic motor displacement control system is characterized by further comprising a pilot oil path, wherein one end of the pilot oil path is communicated with the oil outlet of the pump, the other end of the pilot oil path is communicated with the pilot control oil cylinder (6), a pilot on-off valve (12) and a pressure reducing valve (15) are arranged on the pilot oil path, and the pressure reducing valve (15) is used for adjusting the pilot pressure of hydraulic oil output to the pilot control oil cylinder (6) by the pilot oil path so as to control the displacement control valve (5) to adjust the displacement of the hydraulic motor through the pilot control oil cylinder (6);

the hydraulic control system is characterized by further comprising a shuttle valve, a load feedback oil path and a pilot feedback oil path, wherein one end of the pilot feedback oil path is communicated with the pilot oil path through a one-way valve (14), the other end of the pilot feedback oil path is communicated with the pump feedback oil path through the shuttle valve and used for feeding back pilot hydraulic pressure output by the pilot oil path, one end of the load feedback oil path is communicated with the hydraulic motor, the other end of the load feedback oil path is also communicated with the pump feedback oil path through the shuttle valve and used for feeding back load hydraulic pressure of the hydraulic motor, and the shuttle valve is used for comparing the pilot hydraulic pressure fed back by the pilot feedback oil path with the load hydraulic pressure fed back by the load feedback oil path and outputting hydraulic oil with the highest pressure to the pump feedback oil path.

2. The hydraulic system for load sensing and pilot pressure control of a drilling machine according to claim 1, wherein the hydraulic motors are more than two, the load feedback oil passages are arranged in one-to-one correspondence with the hydraulic motors, the shuttle valves comprise more than two shuttle valves which are connected in series in a grading manner, the output port of the final shuttle valve is communicated with the pump feedback oil passage, and the two input ports of the primary shuttle valve are respectively communicated with the two load feedback oil passages or one load feedback oil passage and the pilot feedback oil passage; in two adjacent upper and lower shuttle valves, one input port of the lower shuttle valve is communicated with the output port of the upper shuttle valve, and the other input port of the lower shuttle valve is communicated with the load feedback oil path or the pilot feedback oil path.

3. The hydraulic system for load sensing and pilot pressure control of a drilling machine according to claim 1, characterized in that the shuttle valve comprises a first shuttle valve (9) and a second shuttle valve (10), the hydraulic motors comprise a first hydraulic motor (3) and a second hydraulic motor (4), the load feedback oil circuit comprises a first load feedback oil circuit and a second load feedback oil circuit which are respectively communicated with the first hydraulic motor (3) and the second hydraulic motor (4), the pilot feedback oil circuit and the first load feedback oil circuit are respectively communicated with two input ports of the first shuttle valve (9), the output port of the first shuttle valve (9) and the second load feedback oil circuit are respectively communicated with two input ports of the second shuttle valve (10), and the output port of the second shuttle valve (10) is communicated with the pump feedback oil circuit.

4. The hydraulic system for load-sensitive and pilot pressure control of a drilling machine according to claim 1, characterized in that the oil supply control valve is a load-sensitive proportional valve (2), the oil inlet of the load-sensitive proportional valve (2) is communicated with the oil outlet of the pump, and the oil outlet of the load-sensitive proportional valve (2) is communicated with the hydraulic motor.

5. The hydraulic system for load sensing and pilot pressure control of a drilling machine according to claim 1, characterized in that the pressure reducing valve (15) is connected with a first oil return path (19) and a second oil return path (20) and is connected with an oil tank through the first oil return path (19) and the second oil return path (20), respectively, and an overflow valve (13) is arranged on the second oil return path (20), and the overflow valve (13) is used for limiting the maximum value of the pilot pressure.

6. The load sensitive and pilot pressure controlled hydraulic system for a drilling rig according to claim 5, characterized in that a speed regulating valve (11) is further provided on the pilot oil circuit for varying the hydraulic oil flow of the pilot oil circuit.

7. The hydraulic system for load sensing and pilot pressure control of a drilling machine according to claim 1, characterized in that the pilot feedback oil path is connected with a third oil return path (21), a damping element (16) is arranged on the third oil return path (21), and the pilot feedback oil path is connected with an oil tank through the third oil return path (21) and the damping element (16).