CN112196855B

CN112196855B - Linear walking control valve, linear walking control system and crawler-type engineering machinery

Info

Publication number: CN112196855B
Application number: CN202011043855.4A
Authority: CN
Inventors: 苏洪昌; 林伟; 刘园
Original assignee: Changde Zhonglian Zhongke Hydraulic Co ltd; Zoomlion Heavy Industry Science and Technology Co Ltd
Current assignee: Changde Zhonglian Zhongke Hydraulic Co ltd; Zoomlion Heavy Industry Science and Technology Co Ltd
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2022-07-26
Anticipated expiration: 2040-09-28
Also published as: CN112196855A

Abstract

The invention relates to engineering machinery and discloses a linear walking control valve which comprises a first load valve, a second load valve, a first load oil port connected with the first load valve, a second load oil port connected with the second load valve, a first external control interface used for controlling the first load valve and a second external control interface used for controlling the second load valve, wherein the first load valve is connected with the second load valve through a load communication channel so as to control the connection and disconnection of the first load oil port and the second load oil port. The invention also discloses a linear walking control system and crawler-type engineering machinery. The linear traveling control valve is applied to a hydraulic system of engineering machinery needing linear traveling, so that the engineering machinery can still keep linear traveling when loads of traveling motors are different, the safety and the reliability are ensured, and the maintenance cost is reduced.

Description

Linear walking control valve, linear walking control system and crawler-type engineering machinery

Technical Field

The invention relates to engineering machinery with a linear traveling function, in particular to a linear traveling control valve. In addition, the invention also relates to a linear motion control system with the linear motion control valve and a crawler-type engineering machine with the linear motion control system.

Background

Some engineering machinery requires to keep straight-line walking during operation, for example, a crawler crane in engineering construction such as industrial hoisting, nuclear power hoisting, road and bridge has a poor working environment and various road conditions, and particularly, when ground with different damping coefficients or operation such as climbing and descending, straight-line walking needs to be realized.

At present, be equipped with two main pumps among the hydraulic system of crawler crane walking commonly used usually, two main pumps are independent respectively for walking motor oil supply about, because the output flow of two main pumps equals, and hydraulic oil only supplies walking motor, consequently the flow of walking motor equals about flowing through, and the rotational speed of walking motor is the same about, thereby crawler crane is no matter advanced simultaneously or is retreated simultaneously and all walks along the straight line.

However, the crawler crane is also required to perform a walking compound action, namely, a compound action of linear walking and other boarding executing mechanisms (such as rotation) is required to be realized; when the left and right traveling valves are operated to move forwards or backwards simultaneously, the other actions and one action of the left traveling or the right traveling are combined, so that the flow rate of the left and right traveling motors is different, the left and right traveling speeds are different, and the crawler crane cannot travel along a straight line.

In order to improve the linear walking capability of the crawler-type walking engineering mechanical equipment during the execution of walking compound actions, the technical means adopted at present is to arrange a linear walking valve in a hydraulic system of the crawler-type walking engineering mechanical equipment, after the linear walking valve is opened, the hydraulic system is changed into a mode that two original main pumps respectively supply oil to walking motors on two sides, one main pump supplies oil to a left walking motor and a right walking motor, and the other main pump supplies oil to an upper vehicle execution mechanism, so that the walking system is independent from the compound working condition, and the purpose of improving the linear walking capability of the crawler-type walking engineering mechanical equipment is achieved.

However, according to the technical scheme of the linear traveling control valve, linear traveling can be maintained only when the loads of the left and right traveling motors are the same, once the loads of the left and right traveling motors are different, the problem of deviation and even turning still occurs, because the loads are different, the pressures of the oil inlet oil paths of the traveling motors on two sides are different, the pressure of the side with the large load is large, the pressure of the side with the small load is small, and hydraulic oil always flows from a high-pressure area to a low-pressure area. Moreover, because the working environment of the engineering mechanical equipment with crawler-type traveling is usually complex and severe, the probability that the left and right traveling motors are subjected to the same load during actual traveling is very small, and even the loads on the two sides are usually greatly different; for example, when the whole crawler crane inclines, the load that the track of the lower one side of level received will be far greater than the track of the higher one side of level, and the hydraulic oil that the single pump provided mostly flows to the motor of the higher one side of level track, and the result that adopts straight line walking valve this moment is that the excavator is to low track one side off tracking even turn, and this not only can't reach the purpose that control excavator keeps straight line walking, still can influence construction safety even on the contrary.

In order to solve the technical problems of the linear traveling control valve, the Chinese patent application with publication number CN102888873A adopts an electrical control mode, various electrical elements are arranged in the system, and specifically, the system needs to be additionally provided with six flow sensors, two traveling controllers, four one-way electro-hydraulic proportional pressure control valves and a pressure switch, so that the cost is more than ten thousand yuan and higher; the reliability of the system itself is reduced because the system incorporates more electrical components and is connected in series. In addition, based on the characteristics of the additionally arranged electrical elements, the one-way electro-hydraulic proportional pressure control valve is arranged on a multi-way valve pilot oil path, the traveling controller is arranged in a cab, the flow sensors are arranged in left and right crawler traveling motor covering pieces, and the flow sensors are distributed dispersedly, so that the assembly and disassembly are inconvenient during maintenance, and even the problem that the frame needs to be modified because the space in the motor covering pieces is not enough to install the flow sensors in the number can occur.

In order to solve the technical problems of the technical scheme of realizing the linear traveling control by adopting an electrical control mode, the chinese patent with the publication number CN106468294B designs a linear traveling control valve, which solves the problem that the engineering machinery cannot keep linear traveling while traveling compound action through the linear traveling control valve and a flow-pressure difference conversion device.

Therefore, there is a need to design a new linear travel control valve to overcome or alleviate the above technical problems.

Disclosure of Invention

The invention aims to provide a linear traveling control valve, which is applied to a hydraulic system of engineering machinery needing linear traveling, so that the engineering machinery can still keep linear traveling when loads of traveling motors are different, the safety and the reliability are ensured, and the maintenance cost is reduced.

The invention further aims to provide a linear travel control system, which can enable the engineering machinery to keep linear travel when the loads of the travel motors are different, so as to ensure the construction safety.

In addition, the technical problem to be solved by the invention is to provide a crawler-type engineering machine, which can enable the engineering machine to keep straight-line walking when the loads of the walking motors are different, ensure the construction safety and have better straight-line walking capability.

In order to solve the technical problem, the invention provides a linear traveling control valve, which comprises a first load valve, a second load valve, a first load oil port connected with the first load valve, a second load oil port connected with the second load valve, a first external control interface for controlling the first load valve, and a second external control interface for controlling the second load valve, wherein the first load valve is connected with the second load valve through a load communication channel so as to control the connection and disconnection of the first load oil port and the second load oil port.

Preferably, the first load valve includes a first oil port and a second oil port connected to the first load oil port, the second load valve includes a first oil port and a second oil port connected to the second load oil port, and the second oil port of the first load valve is communicated with the second oil port of the second load valve through the load communication passage.

Specifically, the first external control interface is connected to a pilot control chamber of the first load valve, and the second external control interface is connected to a pilot control chamber of the second load valve.

Particularly preferably, the first load valve comprises a first reversing valve rod, the second load valve comprises a second reversing valve rod, and at least one of the first reversing valve rod and the second reversing valve rod is connected with an adjusting screw so as to limit the stroke of the first reversing valve rod and/or the second reversing valve rod.

The oil leakage control device comprises a first load valve, a second load valve and an oil tank, and is characterized by further comprising an oil leakage channel, wherein a spring control cavity of the first load valve and a spring control cavity of the second load valve are connected with the oil tank through the oil leakage channel.

The invention also discloses a linear walking control system, which comprises a first walking control valve group, a second walking control valve group, a first walking motor connected with the first walking control valve group, a second walking motor connected with the second walking control valve group and the linear walking control valve in any one of the technical schemes, wherein a first load oil port of the linear walking control valve is connected to an oil path between the first walking control valve group and the first walking motor, and a second load oil port of the linear walking control valve is connected to an oil path between the second walking control valve group and the second walking motor.

Preferably, the first travel control valve group includes a first travel control valve and a first pressure compensation valve, the first travel control valve being connected with the first travel motor through the first pressure compensation valve; the second walking control valve group comprises a second walking control valve and a second pressure compensation valve, and the second walking control valve is connected with the second walking motor through the second pressure compensation valve.

Preferably, the control system further comprises a logic control system, and the logic control system is connected with the control cavity of the first walking control valve, the control cavity of the second walking control valve, and the first external control interface and the second external control interface of the linear walking control valve respectively.

Specifically, the logic control system comprises a first pilot control valve group and a second pilot control valve group, the first pilot control valve group comprises two first pilot valves respectively connected with control cavities at two ends of the first walking control valve, and the second pilot control valve group comprises two second pilot valves respectively connected with control cavities at two ends of the second walking control valve.

Further, a first shuttle valve is arranged between oil outlets of the two first pilot valves, an oil outlet of the first shuttle valve is connected with a first external control interface of the linear walking control valve, a second shuttle valve is arranged between oil outlets of the two second pilot valves, and an oil outlet of the second shuttle valve is connected with a second external control interface of the linear walking control valve.

Preferably, still include main pump, oil feed oil circuit and oil return oil circuit, the main pump passes through the oil feed oil circuit with first walking valves and second walking valves are connected respectively, first walking valves passes through first walking motor with the oil return oil circuit is connected, second walking valves passes through second walking motor with the oil return oil circuit is connected.

Optionally, still include at least one load executive component and at least one load control valves, each load control valves passes through the oil feed oil circuit with the main pump is connected, and each load control valves through corresponding load executive component with the oil return oil circuit is connected.

Typically, an overflow valve is arranged between the oil inlet path and the oil return path.

The invention further discloses crawler-type engineering machinery, which comprises the linear walking control system in any one of the technical schemes.

Through the technical scheme, the invention has the following beneficial effects:

in the basic technical scheme of the invention, the first load valve is connected with the second load valve through the load communication channel, and the respective valve port openings of the first load valve and the second load valve can be respectively controlled through the first external control interface and the second external control interface, so that the communication between the first load oil port and the second load oil port can be realized; when the linear walking control valve is applied to a hydraulic system of engineering mechanical equipment needing linear walking capacity, the first load oil port and the second load oil port are respectively connected with walking motors on two sides of the engineering mechanical equipment, and when loads of the walking motors on the two sides are different, the first load oil port and the second load oil port are controlled to be communicated, so that driving loads are effectively balanced and compensated in real time, hydraulic oil can flow to the two walking motors in an equivalent manner, the problem that linear walking cannot be maintained when linear walking loads are different in the engineering machinery is effectively solved, and the linear walking control valve is simple in oil circuit and high in reliability.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

FIG. 1 is a hydraulic schematic of a straight travel control system according to an embodiment of the present invention;

FIG. 2 is one of the pressure reduction diagrams of the straight-travel control system according to the embodiment of the present invention;

FIG. 3 is a second voltage reduction diagram of the linear motion control system according to the embodiment of the present invention;

FIG. 4 is a third voltage reduction diagram of the straight-line walking control system according to the embodiment of the present invention;

FIG. 5 is a hydraulic schematic of a straight travel control valve according to an embodiment of the present invention;

FIG. 6 is a schematic structural view of a straight travel control valve according to an embodiment of the present invention;

FIG. 7 is a cross-sectional view taken along line A-A of FIG. 6, with the straight travel control valve in a non-operational position;

fig. 8 is a cross-sectional view taken along line a-a of fig. 6, with the straight travel control valve in an operational position.

Description of the reference numerals

11 first load valve e1 first port of first load valve

e second port 12 of the first load valve

f1 first port of second load valve f second port of second load valve

a first loading oil port d second loading oil port

b first external control interface c second external control interface

13 load communication passage 111 first direction valve stem

121 second reversing valve stem 14 adjusting screw

g oil drainage channel 20 first traveling motor

30 first travel motor 21 first travel control valve

22 first pressure compensating valve 31 second travel control valve

32 first pressure compensating valve 41 first pilot valve

42 second pilot valve 43 first shuttle valve

44 first shuttle valve 5 main pump

61 oil inlet oil path 62 oil return path

63 relief valve 71 load actuator

72 load control valve 73 load pressure compensating valve

Detailed Description

The following describes in detail embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration and explanation only, not limitation.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated, therefore, the features defined "first" and "second" may explicitly or implicitly include one or more of the features described.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be connected through inter-element communication or interaction between two elements. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

First, it should be noted that the linear motion control system of the present invention belongs to the hydraulic field, and for those skilled in the art, its substantial technical concept lies in the hydraulic connection relationship. The related hydraulic components, such as a directional control valve, a relief valve, a hydraulic motor, a hydraulic pump, etc., are well known to those skilled in the art and are common components in existing hydraulic systems, and therefore, they will be described only briefly below. After knowing the technical idea of the present invention, a person skilled in the art can also simply replace an oil way or a valve, etc. to implement the function of the linear motion control system of the present invention, which also belongs to the protection scope of the present invention.

As shown in fig. 5, the linear travel control valve according to the basic embodiment of the present invention includes a first load valve 11, a second load valve 12, a first load oil port a connected to the first load valve 11, a second load oil port d connected to the second load valve 12, a first external control port b for controlling the first load valve 11, and a second external control port c for controlling the second load valve 12, where the first load valve 11 is connected to the second load valve 12 through a load communication channel 13, so as to control on/off of the first load oil port a and the second load oil port d.

In the above basic technical solution of the present invention, the first load valve 11 is connected to the first load oil port a, the second load valve 12 is connected to the second load oil port d, the first load valve 11 is connected to the second load valve 12 through the load communicating channel 13, the first external control interface b can control movement of the valve core of the first load valve 11, and the second external control interface c can control movement of the valve core of the second load valve 12, so as to control on/off of the first load oil port a and the second load oil port d; therefore, when the first load oil port a and the second load oil port d are in a conduction state, the pressure at the first load oil port a and the second load oil port d can be balanced, and the driving pressure of the load connected with the first load oil port a and the second load oil port d can be equal.

Therefore, when the straight traveling control valve according to the present invention is applied to a hydraulic system of construction machinery requiring a straight traveling function, referring to fig. 1, in the case where loads of traveling motors on both sides are different, the movement of the spool of the first load valve 11 and the movement of the spool of the second load valve 12 can be controlled to make the first load port a and the second load port d conducted, so that the load driving pressures of the traveling motors on both sides can be equal, to perform load balance compensation, so that the front-rear differential pressure of the spool of the first pressure compensation valve 22 is equal to the front-rear differential pressure of the spool of the second pressure compensation valve 32, in the case where the opening areas of the first traveling control valve 21 and the second traveling control valve 31 are the same, the flow rates of the hydraulic oil flowing into the two traveling motors are made the same, therefore, the engineering mechanical equipment can still keep straight line walking even when the loads of the walking motors on the two sides are different, even the loads are greatly different.

Specifically, the first load valve 11 includes a first port e1 and a second port e, the first port e1 of the first load valve 11 is connected to the first load port a, the second load valve 12 includes a first port f1 and a second port f, the first port f1 of the second load valve 12 is connected to the second load port d, and the second port e of the first load valve 11 is communicated with the second port f of the second load valve 12 through the load communication passage 13.

The first external control interface b is connected with a pilot control cavity of the first load valve 11, and the second external control interface c is connected with a pilot control cavity of the second load valve 12; the first load valve 11 and the second load valve 12 are preferably hydraulic pilot reversing valves, the first external control interface b controls the make-and-break of the first port e1 and the second port e of the first load valve 11, and the second external control interface c controls the make-and-break of the first port f1 and the second port f of the second load valve 12, so as to control the make-and-break of the first load port a and the second load port d. Of course, the first and

second load valves

11 and 12 may be controlled by other means, for example, the first and

second load valves

11 and 12 may be pneumatic control valves, solenoid valves, etc.

As shown in fig. 6 to 8, a first direction valve rod 111 is arranged in the first load valve 11, and a second direction valve rod 121 is arranged in the second load valve 12, so that the linear motion control valve of the present invention can be adapted to different types of devices, an adjusting screw 14 may be arranged on the first load valve 11 or the second load valve 12, and the first direction valve rod 111 is connected to the adjusting screw 14, or the second direction valve rod 121 is connected to the adjusting screw 14, or both are connected to the adjusting screw 14; taking the specific structure of fig. 7 and 8 for connecting the adjusting screw 14 to the first direction-changing valve rod 111 as an example for explanation, as shown in fig. 7, when the straight-traveling control valve of the present invention is in an initial state, i.e., in a non-operating position, the end of the adjusting screw 14 is at a distance L from the end of the first direction-changing valve rod 111, so as to limit the moving stroke of the first direction-changing valve rod 111; as shown in fig. 8, the pilot oil flows from the first external control port b to the pilot control chamber of the first load valve 11, and the pilot oil flows from the second external control port c to the pilot control chamber of the second load valve 12, so that the first direction changing valve rod 111 moves by a distance L, the first load port a communicates with the second load port d, and the load driving pressures at both ends can be substantially the same. The first load valve 11 and the second load valve 12 may be in the form of inserts, and are connected together by a valve body.

In addition, an oil drainage channel g is further arranged in the linear traveling control valve, one end of the oil drainage channel g is respectively connected with the spring control cavity of the first load valve 11 and the spring control cavity of the second load valve 12, the other end of the oil drainage channel g is connected with an oil tank, hydraulic oil which is internally drained is discharged out of the shell of the linear traveling control valve, and therefore damage to the sealing structure and the shell are prevented.

In order to facilitate understanding of the technical concept of the present invention, the linear travel control valve of the present invention is applied to a specific hydraulic system for explanation.

As shown in fig. 1, the linear travel control system of the present invention includes a first travel control valve set, a second travel control valve set, a first travel motor 20, and a second travel motor 30, wherein the first travel control valve set is connected to the first travel motor 20, and is capable of conveying hydraulic oil to the first travel motor 20 through the first travel control valve set to drive the first travel motor 20, the second travel control valve set is connected to the second travel motor 30, and is capable of conveying hydraulic oil to the second travel motor 30 through the second travel control valve set to drive the second travel motor 30; a first load port a of the straight traveling control valve is connected to an oil path between the first traveling control valve group and the first traveling motor 20, and a second load port d of the straight traveling control valve is connected to an oil path between the second traveling control valve group and the second traveling motor 30. The first traveling control valve group and the second traveling control valve group are supplied with oil by the same hydraulic pump, and the linear traveling control valve is adjusted to communicate the first load oil port a and the second load oil port d of the linear traveling control valve, so that the load driving pressures of the first traveling motor 20 and the second traveling motor 30 are balanced, the flow rates flowing into the first traveling motor 20 and the second traveling motor 30 are equal, and the linear traveling function is realized. The first and

second travel motors

20 and 30 are preferably bidirectional hydraulic motors.

Specifically, the first travel control valve group includes a first travel control valve 21 and a first pressure compensation valve 22, and the first travel control valve 21 is connected to the first travel motor 20 through the first pressure compensation valve 22; the second travel control valve group includes a second travel control valve 31 and a second pressure compensation valve 32, and the second travel control valve 31 is connected to the second travel motor 30 through the second pressure compensation valve 32.

Further, the main pump 5 is connected to the first traveling control valve 21 and the second traveling control valve 31 through the oil inlet passage 61, the first traveling control valve 21 is connected to the first traveling motor 20 through the first pressure compensating valve 22, the first traveling motor 20 is connected to the oil return passage 62 through the first traveling control valve 21, the second traveling control valve 31 is connected to the second traveling motor 30 through the second pressure compensating valve 32, the second traveling motor 30 is connected to the oil return passage 62 through the second traveling control valve 31, the first load port a of the linear traveling control valve is connected to the oil passage between the first traveling control valve 21 and the first traveling motor 20, and the second load port d of the linear traveling control valve is connected to the oil passage between the second traveling control valve 31 and the second traveling motor 30. In this way, the hydraulic oil provided by the main pump 5 flows through the oil inlet path 61 to the first traveling control valve 21 and the second traveling control valve 31, and then flows to the corresponding first traveling motor 20 and the second traveling motor 30 through the first pressure compensating valve 22 and the second pressure compensating valve 32, respectively, to drive the first traveling motor 20 and the second traveling motor 30, and by providing the linear traveling control valve of the present invention, in the case where the load driving pressures of the first traveling motor 20 and the second traveling motor 30 are different, when the linear traveling function is required, the first load port a and the second load port d of the linear traveling control valve are controlled to communicate, and the pressures at both ends are balanced, so that the front-rear differential pressure of the spool of the first traveling control valve 21 is equal to the front-rear differential pressure of the spool of the second traveling control valve 31, and at this time, it is only necessary that the opening areas of the spools of the first traveling control valve 21 and the second traveling control valve 31 are equal, it is possible to make the flow rate allocated to the first and second traveling motors 20 and 30 the same, thereby implementing the straight traveling function. Of these, the main pump 5 is preferably a variable displacement hydraulic pump.

Further, an overflow valve 63 is arranged between the oil inlet path 61 and the oil return path 62 to ensure the safety of the system.

Further, a logic control system may be provided to control the first travel control valve 21, the second travel control valve 31, and the straight travel control valve; for example, the logic control system is connected to the control chamber of the first travel control valve 21, the control chamber of the second travel control valve 31, and the first external control port b and the second external control port c of the linear travel control valve, respectively.

The structure forms of the logic control system are various, for example, the logic control system may include a first pilot control valve group and a second pilot control valve group, the first pilot control valve group includes two first pilot valves 41, the two first pilot valves 41 are respectively connected with the control cavities at the two ends of the first walking control valve 21 in a one-to-one correspondence manner, the second pilot control valve group includes two second pilot valves 42, and the two second pilot valves 42 are respectively connected with the control cavities at the two ends of the second walking control valve 31 in a one-to-one correspondence manner; the oil return ports of the two first pilot valves 41 are connected with the oil inlet path 61 through a pressure reducing valve, the oil return ports of the two first pilot valves 41 are connected with an oil tank through an overflow valve, the oil outlets of the two first pilot valves 41 are respectively connected with a one-way throttle valve, a first shuttle valve 43 is arranged between the oil outlets of the two first pilot valves 41, and the oil outlet of the first shuttle valve 43 is connected with a first external control interface b of the linear walking control valve; the oil return ports of the two second pilot valves 42 are connected with the oil inlet path 61 through a pressure reducing valve, the oil return ports of the two second pilot valves 42 are connected with an oil tank through an overflow valve, the oil outlets of the two second pilot valves 42 are respectively connected with a one-way throttle valve, a second shuttle valve 44 is arranged between the oil outlets of the two second pilot valves 42, and the oil outlet of the second shuttle valve 44 is connected with a second external control interface c of the linear walking control valve.

Other boarding actuators (such as a boom, a swing, a winch and the like) can be connected to the linear travel control system, and specifically, referring to fig. 1, the linear travel control system includes at least one load actuator 71 and at least one load control valve group, the load control valve group includes a load control valve 72 and a load pressure compensation valve 73, control chambers at two ends of the load control valve 72 are respectively connected with one pilot valve, a one-way throttle valve is arranged between each pilot valve and a corresponding control chamber of the load control valve 72, and the load control valve 72 is connected with the load actuator 71 through the load pressure compensation valve 73. In this way, when the main pump 5 delivers hydraulic oil to the first travel control valve 21, the second travel control valve 31, and the load control valve 72, respectively, a travel complex operation occurs, and the linear travel control valve of the present invention acts to equalize the flow rates to the first travel control valve 21 and the second travel control valve 31, thereby preventing the occurrence of a problem of a difference in the flow rates of the first travel motor 20 and the second travel motor 30 due to the influence of the load actuator 71, and effectively realizing a linear travel function. The load actuator 71 may be a hydraulic element such as a hydraulic motor or a hydraulic cylinder.

In order to better understand the operation principle of the linear motion control valve in the linear motion control system, the following description will be made in detail with reference to fig. 2 to 4, and for the sake of simplicity of description, the first travel motor 20 is a right travel motor, and the second travel motor 30 is a left travel motor.

While traveling in a straight line

In the example of fig. 2, the straight travel control valve of the present invention is not provided, and the flow sensing port AJ1 is connected to the first travel motor 20 through the corresponding first pressure compensating valve 22, and the flow sensing port AJ2 is connected to the second travel motor 30 through the corresponding second pressure compensating valve 32; when the first traveling control valve 21 and the second traveling control valve 31 are switched to the left position, the forward straight traveling is set, the opening areas of the flow sensing port AJ1 and the flow sensing port AJ2 are the same, the first pressure compensation valve 22 is switched from the left position to the right position through the middle position by delivering hydraulic oil to the control chamber d1 of the first pressure compensation valve 22, the second pressure compensation valve 32 is switched from the left position to the right position through the middle position by delivering hydraulic oil to the control chamber d2 of the second pressure compensation valve 32, the rear pressure of the flow sensing port in front of the first pressure compensation valve 22 is Pc1, the rear pressure of the flow sensing port in front of the second pressure compensation valve 32 is Pc2, and the rear pressure is transmitted to the variable mechanism of the main pump 5 through the load feedback port Pls of the main pump 5 to perform variable feedback; hydraulic oil respectively enters the first traveling motor 20 and the second traveling motor 30, the driving motors operate, when the load driving pressure Pa1 of the first traveling motor 20 is the same as the load driving pressure Pa2 of the second traveling motor 30, the front-rear differential pressure Δ Pd1 of the spool of the first pressure compensating valve 22 is equal to the front-rear differential pressure Δ Pd2 of the spool of the second pressure compensating valve 32, and the opening areas of the flow sensing ports AJ1 and AJ2 are the same, so that Δ Pp — Δ Pd1 is equal to Δ Pp — Δ Pd2, where Pp is the outlet pressure of the main pump 5 and Δ Pp is the pump pressure difference, and therefore, the flow rates passing through the flow sensing ports AJ1 and AJ2 are equal to each other, and linear traveling is realized.

However, when a combined operation of the linear travel and the other boarding actuators such as the swing is required, the main pump 5 also supplies the hydraulic oil to the load actuator 71, and a part of the hydraulic oil flows to the load actuator 71 through the flow sensing port AJ3 and the load pressure compensating valve 73, resulting in a difference in flow rate to the first travel motor 20 and the second travel motor 30, and a difference in left and right travel speeds, and thus a linear travel cannot be achieved. Hydraulic oil is conveyed to a control cavity d3 of the load pressure compensation valve 73, so that the load pressure compensation valve 73 is switched from a left position to a right position through a middle position, the front flow sensing port rear pressure Pc3 of the load pressure compensation valve 73 is increased, and the front-rear pressure difference of a valve core of the load pressure compensation valve 73 is delta Pd 3.

When the first travel control valve 21 and the second travel control valve 31 are reversed to the right position, the backward straight travel is set, which is the same principle as the forward straight travel described above.

Fig. 3 is an example in which the linear travel control valve of the present invention is provided on the basis of the example of fig. 2, when the first travel control valve 21 and the second travel control valve 31 are switched to the left position, the linear travel control valve is set to travel straight forward, and at this time, the opening areas of the flow sensing port AJ1 and the flow sensing port AJ2 are the same, the first pressure compensation valve 22 is switched from the left position to the right position through the middle position by feeding hydraulic oil to the control chamber d1 of the first pressure compensation valve 22, the second pressure compensation valve 32 is switched from the left position to the right position through the middle position by feeding hydraulic oil to the control chamber d2 of the second pressure compensation valve 32, the rear pressure of the flow sensing port in front of the first pressure compensation valve 22 is Pc1, the rear pressure of the flow sensing port in front of the second pressure compensation valve 32 is Pc2, and the rear pressure of the flow sensing port in front of the main pump 5 is transmitted to the variable mechanism of the main pump 5 for variable feedback; hydraulic oil respectively enters the first traveling motor 20 and the second traveling motor 30, the driving motors operate, when the load driving pressure Pa1 of the first traveling motor 20 is greater than the load driving pressure Pa2 of the second traveling motor 30, the load driving pressure Pa1 and the load driving pressure Pa2 side are provided with the linear traveling control valve of the present invention, at this time, the linear traveling control valve of the present invention does not work, that is, the first load port a of the linear traveling control valve and the second load port d of the linear traveling control valve are in a cut-off state, the front-rear differential pressure Δ Pd1 of the spool of the first pressure compensation valve 22 is greater than the front-rear differential pressure Δ Pd2 of the spool of the second pressure compensation valve 32, so that Δ Pp- Δ Pd1 is smaller than Δ Pp- Δ Pd2, and the opening areas of the flow sensing ports AJ1 and AJ2 are the same, so that the flow passing through the flow sensing port AJ1 is smaller than the flow sensing port AJ2, so that the straight walking cannot be realized.

In the example of fig. 4, the linear travel control valve of the present invention is provided in addition to the example of fig. 2, specifically, the linear travel control valve of the present invention is provided on the load drive pressure Pa1 and the load drive pressure Pa2 side, when there is a difference between the load drive pressure Pa1 and the load drive pressure Pa2, the first load port a of the linear travel control valve and the second load port d of the linear travel control valve are brought into a conduction state by hydraulic pressure automatic recognition of the positions of the first travel control valve 21 and the second travel control valve 31 being switched, the load drive pressure Pa1 of the first travel motor 20 and the load drive pressure Pa2 of the second travel motor 30 are load-balanced and compensated, the load drive pressure Pa1 is Pa2, and the Δ Pd1 is 2, so that Δ Pp — Δ Pd1 — Δ Pd — Δ 2 are maintained, and the induced flow rates through the induced ports Δ AJ1 and AJ 34 are equal in opening area, and therefore the induced flow rates through the induced ports AJ are equal to Δ 2, thereby realizing straight-line walking.

When performing linear traveling load balance compensation, referring to fig. 7 and 8, a load driving pressure Pa1 of the first traveling motor 20 is connected to the first load valve 11 through the first load port a, a load driving pressure Pa2 of the second traveling motor 30 is connected to the second load valve 12 through the second load port d, and the logic control system pushes the first direction changing valve rod 111 through the first external control interface b to change the direction of the first load valve 11, opens the first port e1 of the first load valve 11, and communicates the first load port a with the second port e of the first load valve 11, where the adjustment screw 14 can limit the stroke of the first direction changing valve rod 111 and control the port opening of the first port e1 of the first load valve 11; meanwhile, the logic control system pushes the first reversing valve rod 121 through the first external control interface c to reverse the second load valve 12, opens the first port f1 of the second load valve 12, and communicates the second load port d with the second port f of the second load valve 12, because the second port e of the first load valve 11 is communicated with the second port f of the second load valve 12 through the load communication channel 13, the load driving pressure Pa1 of the first traveling motor 20 is communicated with the load driving pressure Pa2 of the second traveling motor 30 through the first load port a and the second load port d, load balance compensation is performed, and a linear traveling function is realized.

When walking in a non-straight line

When the first and second traveling

control valves

21 and 31 are switched to different working positions, for example, a left working position and a right working position, the load balance compensation method is the same as that of the straight traveling, so that pivot turning can be performed.

For another example, when the logic control system pushes the first direction changing valve rod 111 through the first external control interface b to change the direction of the first load valve 11, open the first port e1 of the first load valve 11, communicate the first load port a with the second port e of the first load valve 11, and control the first traveling control valve 21 to change the direction at the same time, but the second traveling control valve 31 is not changed in the middle position, at this time, the first load port a is not communicated with the second load port d, so the load driving pressure Pa1 of the first traveling motor 20 is not communicated with the load driving pressure Pa2 of the second traveling motor 30, and the load balancing compensation function is cut off, thereby enabling the single-side turning action. In the same way, the second travel control valve 31 may be controlled to change direction, and the first travel control valve 21 may be controlled to change direction at the neutral position without changing direction, and may also perform a single-side turning operation.

In order to further understand the technical idea and advantages of the present invention, the following describes a structural form of the linear walking control system of the present invention with relatively comprehensive preferred features.

As shown in fig. 1 to 8, the main pump 5 is connected to the first traveling control valve 21, the second traveling control valve 31, and the load control valve 72 through the oil inlet passage 61, the first traveling control valve 21 is connected to the first traveling motor 20 through the first pressure compensating valve 22, the second traveling control valve 31 is connected to the second traveling motor 30 through the second pressure compensating valve 32, the first load port a of the straight traveling control valve is connected to an oil passage between the first traveling control valve 21 and the first traveling motor 20, the second load port d of the straight traveling control valve is connected to an oil passage between the second traveling control valve 31 and the second traveling motor 30, and the load control valve 72 is connected to the load actuator 71 through the load pressure compensating valve 73; the oil outlets of the two first pilot valves 41 are respectively connected with a one-way throttle valve and are connected with control cavities on two sides of the first walking control valve 21 through the one-way throttle valve, a first shuttle valve 43 is arranged between the oil outlets of the two first pilot valves 41, the oil outlet of the first shuttle valve 43 is connected with a first external control interface b of the linear walking control valve, the oil outlets of the two second pilot valves 42 are respectively connected with a one-way throttle valve and are connected with the control cavities on two sides of the second walking control valve 31 through the one-way throttle valve, a second shuttle valve 44 is arranged between the oil outlets of the two second pilot valves 42, the oil outlet of the second shuttle valve 44 is connected with a second external control interface c of the linear walking control valve, and the control cavities on two sides of the load control valve 72 are also respectively connected with the pilot valves; the linear traveling control valve comprises a first load valve 11 and a second load valve 12, a first reversing valve rod 111 is arranged in the first load valve 11, an adjusting screw 14 connected with the first reversing valve rod 111 is arranged on the first load valve 11 so as to limit the stroke of the first load valve 11, a first external control interface b is connected with a pilot control cavity of the first load valve 11, the first pilot valve 41 is operated, the first reversing valve rod 111 can be driven through the first external control interface b, and a first oil port e1 of the first load valve 11 is communicated with a first load oil port a; a second reversing valve rod 121 is arranged in the second load valve 12, a second external control interface c is connected with a pilot control cavity of the second load valve 12, the second pilot valve 41 is operated, the second reversing valve rod 121 can be driven through the second external control interface c, and the first oil port f1 and the second oil port f of the second load valve 12 are communicated.

Under the condition that straight-line walking is not needed, only the first pilot valve 41 or the second pilot valve 42 needs to be operated to reverse the first walking control valve 21 or the second walking control valve 31, so that unilateral turning action can be realized, or the first pilot valve 41 and the second pilot valve 42 are operated simultaneously to reverse the first walking control valve 21 and the second walking control valve 31 to opposite directions, so that pivot turning is realized; the linear traveling control valve does not work, that is, the first load port a and the second load port d are not communicated.

When the linear traveling function is required, the first pilot valve 41 and the second pilot valve 42 are operated simultaneously, the first traveling control valve 21 and the second traveling control valve 31 are caused to reverse in the same direction, for example, the first traveling control valve 21 and the second traveling control valve 31 are caused to forward or backward jointly, at the same time, the first pilot valve 41 is caused to convey pilot oil to the first external control interface b through the first shuttle valve 43, the first reversing valve rod 111 is driven to move through the first external control interface b, the first load valve 11 is caused to reverse, the first oil port e1 and the second oil port e of the first load valve 11 are caused to be communicated, the second pilot valve 42 is caused to convey pilot oil to the second external control interface c through the second shuttle valve 44, the second reversing valve rod 121 is driven to move through the second external control interface c, the second load valve 12 is caused to reverse, the first oil port f1 and the second oil port f of the second load valve 12 are caused to be communicated, and the second oil port e of the first load valve 11 is caused to be communicated with the second oil port f of the second load valve 12 through the load communication passage 13, therefore, the load driving pressure Pa1 of the first travel motor 20 and the load driving pressure Pa2 of the second travel motor 30 are allowed to communicate with each other, and the load pressures are balanced so that the load driving pressure Pa1 of the first travel motor 20 and the load driving pressure Pa2 of the second travel motor 30 are made equal to each other; therefore, when walking composite action is carried out or the loads of the walking motors on two sides are different, the change fluctuation of the driving load does not influence linear walking, the driving load can be effectively balanced and compensated in real time, the problem that the linear walking cannot be maintained when the linear walking loads are different in engineering machinery is effectively solved, an oil circuit is simple, the linear walking control system and the linear walking control valve provided by the invention are mainly composed of mechanical control components of hydraulic valves, extra control strategies such as electric devices do not exist, the linear walking performance can be efficiently and reliably controlled in the working conditions of frequent operation and various driving loads, and the reliability is high.

It should be noted that, in the above-described embodiments, the linear travel control system of the present invention is mainly applied in combination with a single pump system, but it is needless to say that the linear travel control system of the present invention may be applied to a double pump system, for example, two hydraulic pumps independently supply oil to left and right travel motors, and when a travel composite operation is performed, one hydraulic pump supplies oil to the left and right travel motors and the other hydraulic pump supplies oil to other loads.

The linear walking control system can be applied to various engineering mechanical equipment with crawler walking, such as a crawler crane and a crawler excavator.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, numerous simple variants are possible, comprising the combination of the individual specific technical features in any suitable manner. The invention is not described in detail in order to avoid unnecessary repetition. Such simple modifications and combinations should be considered within the scope of the present disclosure as well.

Claims

1. The linear walking control system is characterized by comprising a first walking control valve group, a second walking control valve group, a first walking motor (20) connected with the first walking control valve group, a second walking motor (30) connected with the second walking control valve group and a linear walking control valve, wherein the linear walking control valve comprises a first load valve (11), a second load valve (12), a first load oil port (a) connected with the first load valve (11), a second load oil port (d) connected with the second load valve (12), a first external control interface (b) used for controlling the first load valve (11) and a second external control interface (c) used for controlling the second load valve (12), and the first load valve (11) is connected with the second load valve (12) through a load communication channel (13), so as to control the on-off of the first load oil port (a) and the second load oil port (d); a first load oil port (a) of the linear traveling control valve is connected to an oil path between the first traveling control valve group and the first traveling motor (20), and a second load oil port (d) of the linear traveling control valve is connected to an oil path between the second traveling control valve group and the second traveling motor (30); the first travel control valve group comprises a first travel control valve (21) and a first pressure compensation valve (22), the first travel control valve (21) being connected with the first travel motor (20) through the first pressure compensation valve (22); the second walking control valve group comprises a second walking control valve (31) and a second pressure compensation valve (32), and the second walking control valve (31) is connected with the second walking motor (30) through the second pressure compensation valve (32).

2. The straight traveling control system according to claim 1, wherein the first load valve (11) includes a first port (e 1) and a second port (e) connected to the first load port (a), the second load valve (12) includes a first port (f 1) and a second port (f) connected to the second load port (d), and the second port (e) of the first load valve (11) is communicated with the second port (f) of the second load valve (12) through the load communication passage (13).

3. Straight walking control system according to claim 1, characterized in that the first external control interface (b) is connected with the pilot control chamber of the first load valve (11) and the second external control interface (c) is connected with the pilot control chamber of the second load valve (12).

4. The straight travel control system according to claim 1, wherein the first load valve (11) comprises a first direction change valve stem (111), the second load valve (12) comprises a second direction change valve stem (121), and an adjusting screw (14) is connected to at least one of the first direction change valve stem (111) and the second direction change valve stem (121) so as to limit the stroke of the first direction change valve stem (111) and/or the second direction change valve stem (121).

5. The straight travel control system according to any one of claims 1 to 4, further comprising a drain passage (g) through which the spring control chamber of the first load valve (11) and the spring control chamber of the second load valve (12) are connected with a tank.

6. The straight travel control system according to claim 1, further comprising a logic control system connected to the control chamber of the first travel control valve (21), the control chamber of the second travel control valve (31), and the first external control port (b) and the second external control port (c) of the straight travel control valve, respectively.

7. The linear travel control system according to claim 6, characterized in that the logic control system comprises a first pilot valve group comprising two first pilot valves (41) connected to the two-end control chambers of the first travel control valve (21), respectively, and a second pilot valve group comprising two second pilot valves (42) connected to the two-end control chambers of the second travel control valve (31), respectively.

8. The linear walking control system according to claim 7, characterized in that a first shuttle valve (43) is arranged between oil outlets of the two first pilot valves (41), the oil outlet of the first shuttle valve (43) is connected with a first external control interface (b) of the linear walking control valve, a second shuttle valve (44) is arranged between oil outlets of the two second pilot valves (42), and the oil outlet of the second shuttle valve (44) is connected with a second external control interface (c) of the linear walking control valve.

9. The straight-line walking control system according to any one of claims 6 to 8, further comprising a main pump (5), an oil inlet path (61) and an oil return path (62), wherein the main pump (5) is connected with the first and second walking control valve sets through the oil inlet path (61), the first walking control valve set is connected with the oil return path (62) through the first walking motor (20), and the second walking control valve set is connected with the oil return path (62) through the second walking motor (30).

10. The linear walking control system according to claim 9, further comprising at least one load actuator (71) and at least one load control valve group, wherein each load control valve group is connected to the main pump (5) through the oil inlet passage (61), and each load control valve group is connected to the oil return passage (62) through the corresponding load actuator (71).

11. The linear walking control system according to claim 9, wherein an overflow valve (63) is arranged between the oil inlet passage (61) and the oil return passage (62).

12. A track-type working machine, characterized by comprising a straight-travel control system according to any one of claims 1 to 11.