A steering hydraulic control system and a working machine

Abstract

The application discloses a steering hydraulic control system and engineering machinery, wherein the steering hydraulic control system comprises an oil supply module, a flow control module, a direction control module, a steering cylinder and a steering gear, the steering gear is used for generating a pilot pressure signal according to hydraulic oil, the direction control module is used for respectively controlling the hydraulic flow of the flow control module to the steering cylinder, the pilot flow of the steering gear to the pressure receiving end of the flow control module and the oil return flow of the steering cylinder to the oil supply module according to the pilot pressure signal, and the flow control module is used for adjusting the hydraulic flow output by the oil supply module to the direction control module according to the pilot pressure signal. The steering hydraulic control system and the engineering machinery can simplify the flow control structure of the hydraulic system, reduce the noise generated in the steering process and improve the steering operation comfort.

Description

Technical Field

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

[0002] For construction machinery such as loaders, the required flow rate for left and right steering is the same. The left and right output flow rates are ensured by the machining precision of the valve core, but a certain flow rate difference still exists. To solve the problem of the difference in left and right flow rates, a flow control valve assembly is generally used to achieve a balance between the left and right flow rates.

[0003] However, in practice, current flow control valve assemblies require multiple valve cores to achieve synchronous left and right flow control, making the hydraulic system complex and costly. Furthermore, the high-pressure pilot flow control at both ends of the valve core switching mechanism in flow control valve assemblies can cause noise during steering in applications such as loaders and other construction machinery. Additionally, the pilot control of high-pressure flow can negatively impact steering comfort.

[0004] Therefore, how to simplify the flow control structure of the hydraulic system, reduce noise during steering, and improve the comfort of steering operation has become an urgent problem to be solved. Summary of the Invention

[0005] This invention discloses a steering hydraulic control system and engineering machinery, which can simplify the flow control structure of the hydraulic system, reduce noise generated during steering, and improve the comfort of steering operation.

[0006] To achieve the above objectives, in a first aspect, the present invention discloses a steering hydraulic control system, the steering hydraulic control system comprising: The oil supply module is used to pump hydraulic oil; A flow control module, wherein the flow control module is connected to the oil circuit of the pump port of the oil supply module; A directional control module is connected to the return oil circuit of both the flow control module and the oil supply module. A steering cylinder is connected to the hydraulic circuit of the direction control module and is used to perform steering operations according to the hydraulic oil. The steering gear is connected to the oil supply module and the pressure receiving end oil circuit of the direction control module respectively, and the direction control module is also connected to the steering gear and the pressure receiving end oil circuit of the flow control module respectively. The steering gear is used to generate a pilot pressure signal based on the hydraulic oil. The direction control module is used to control the hydraulic flow of the steering cylinder by the flow control module, the pilot flow of the steering gear to the pressure receiving end of the flow control module, and the return flow of the steering cylinder to the oil supply module based on the pilot pressure signal. The flow control module is used to adjust the hydraulic flow output by the oil supply module to the direction control module based on the pilot pressure signal.

[0007] As an optional implementation, in an embodiment of the first aspect of the present invention, the direction control module includes: A directional control valve, wherein the pilot feed port of the directional control valve is connected to the oil circuit of the pressure receiving end of the steering gear and the flow control module respectively, the oil inlet of the directional control valve is connected to the oil outlet of the flow control module, the oil outlet of the directional control valve is connected to the oil circuit of the steering cylinder, and the oil return feed port of the directional control valve is connected to the oil return port of the oil supply module. A directional control throttle orifice is provided in the oil passage between the pressure receiving end of the directional control valve and the steering gear; The directional control valve is used to switch the valve core position according to the pilot pressure signal, so as to control the hydraulic flow of the flow control module to the steering cylinder, the pilot flow of the steering gear to the pressure receiving end of the flow control module, and the return flow of the steering cylinder to the oil supply module.

[0008] As an optional implementation, in an embodiment of the first aspect of the present invention, the flow control module includes: A flow control valve is provided, wherein the inlet of the flow control valve is connected to the pump port of the oil supply module, the outlet of the flow control valve is connected to the inlet of the directional control valve, the first pressure receiving end and the second pressure receiving end of the flow control valve are both connected to the pilot delivery port of the directional control valve, and the pilot delivery port of the flow control valve is connected to both the pilot delivery port of the directional control valve and the second pressure receiving end of the flow control valve. The flow control valve is used to adjust the hydraulic flow output by the oil supply module to the inlet of the directional control valve according to the pilot pressure signal. A pressure compensation unit is provided, which is connected to the oil supply module and the oil inlet of the flow control valve respectively. The pressure receiving end of the pressure compensation unit is connected to the pressure feedback port of the flow control valve. The pressure compensation unit is used to compensate the hydraulic pressure of the flow control valve according to the hydraulic pressure of the oil inlet of the flow control valve.

[0009] As an optional implementation, in an embodiment of the first aspect of the present invention, the pressure compensation unit includes: A priority valve is provided, with its inlet connected to the oil supply module's oil circuit, its outlet connected to the inlet oil circuit of the flow control valve, its first pressure receiving end connected to the outlet oil circuit of the priority valve, and its second pressure receiving end connected to both the outlet oil circuit of the priority valve and the pressure feedback port oil circuit of the flow control valve. The pressure compensation unit is used to perform hydraulic pressure compensation on the flow control valve based on the hydraulic pressure at the inlet oil circuit of the flow control valve. The first priority throttling orifice is disposed in the oil line between the first pressure receiving end of the priority valve and the oil outlet of the priority valve. The second priority throttling orifice is disposed in the oil line between the second pressure receiving end of the priority valve and the oil outlet of the priority valve; The third priority throttling orifice is located in the oil line between the second pressure receiving end of the priority valve and the pressure feedback port of the flow control valve.

[0010] As an optional implementation, in an embodiment of the first aspect of the present invention, the flow control module further includes: The first flow control throttle orifice is disposed on the oil passage between the first pressure receiving end of the flow control valve and the pilot delivery port of the directional control valve. The second flow control throttle orifice is disposed on the oil passage between the second pressure receiving end of the flow control valve and the pilot delivery port of the directional control valve.

[0011] As an optional implementation, in an embodiment of the first aspect of the present invention, the steering hydraulic control system further includes: An overflow valve, wherein the oil inlet of the overflow valve is connected to the oil pump port of the oil supply module, and the oil outlet of the overflow valve is connected to the oil return port of the oil supply module. A back pressure valve, wherein the oil inlet of the back pressure valve is connected to the oil return supply port of the directional control valve, and the oil outlet of the back pressure valve is connected to the oil return port of the oil supply module. The target check valve has its inlet connected to the outlet of the relief valve. The oil replenishment control module is connected to the oil circuits of the steering cylinder, the oil outlet of the target check valve, and the oil inlet of the back pressure valve.

[0012] As an optional implementation, in an embodiment of the first aspect of the present invention, the oil replenishment control module includes: The first replenishing check valve has its inlet connected to the outlet of the target check valve and the return oil supply port of the directional control valve, and its outlet is connected to the first inner cavity oil passage of the steering cylinder. The first overload valve has its inlet connected to the first internal cavity oil passage of the steering cylinder, and its outlet connected to the inlet oil passage of the back pressure valve. The second replenishing check valve has its inlet connected to the outlet of the target check valve and the return oil supply port of the directional control valve, and its outlet connected to the second inner cavity oil passage of the steering cylinder. The second overload valve has its inlet connected to the second inner cavity oil passage of the steering cylinder, and its outlet connected to the inlet oil passage of the back pressure valve.

[0013] As an optional implementation, in an embodiment of the first aspect of the present invention, the steering hydraulic control system further includes: A pressure reducing valve is provided between the oil pump port of the oil supply module and the oil inlet of the steering gear.

[0014] As an optional implementation, in an embodiment of the first aspect of the present invention, the oil supply module includes: A hydraulic oil tank, used to store hydraulic oil; A hydraulic pump is connected to the hydraulic oil tank, the flow control module, and the steering gear oil circuit, respectively. The hydraulic pump is used to pump the hydraulic oil in the hydraulic oil tank to the flow control module and the steering gear.

[0015] Secondly, the present invention discloses an engineering machinery, characterized in that it comprises: Construction machinery body; The steering hydraulic control system as described in the first aspect of the present invention is disposed in the body of the engineering machinery.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The steering hydraulic control system provided by this invention controls the balance of left and right output flow by using a flow control module with only one flow control valve, thereby simplifying the flow control structure of the hydraulic system and reducing system cost. At the same time, the hydraulic pressure is converted into a low-pressure pilot pressure signal through the steering gear to achieve low-pressure pilot control of the flow control module, thereby reducing noise generated during steering and improving the comfort of steering operation.

[0017] The engineering machinery provided by this invention adopts the aforementioned steering hydraulic control system. By using a flow control module with only one flow control valve to control the balance of the left and right output flow, the flow control structure of the hydraulic system is simplified, and the system cost is reduced. At the same time, the hydraulic pressure is converted into a low-pressure pilot pressure signal through the steering gear, thereby realizing low-pressure pilot control of the flow control module, which reduces the noise generated during steering and improves the comfort of steering operation. Attached Figure Description

[0018] Figure 1 This is a block diagram of the steering hydraulic control system in this invention; Figure 2 This is a schematic diagram of a specific embodiment of the steering hydraulic control system in this invention.

[0019] The meanings of the reference numerals in the attached figures are as follows: Oil supply module 100, hydraulic oil tank 110, hydraulic pump 120, flow control module 200, flow control valve 210, pressure compensation unit 220, priority valve 221, first priority throttle orifice 222, second priority throttle orifice 223, third priority throttle orifice 224, first flow control throttle orifice 230, second flow control throttle orifice 240, direction control module 300, direction control valve 310, direction control throttle orifice 320, steering cylinder 400, steering gear 500, relief valve 610, back pressure valve 620, target check valve 630, replenishment control module 640, first replenishment check valve 641, first overload valve 642, second replenishment check valve 643, second overload valve 644, pressure reducing valve 650. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0022] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0023] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0024] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0025] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0026] For construction machinery such as loaders, the required flow rate for left and right steering is the same. The left and right output flow rates are ensured by the machining precision of the valve core, but a certain flow rate difference still exists. To solve the problem of the difference in left and right flow rates, a flow control valve assembly is generally used to achieve a balance between the left and right flow rates.

[0027] However, in practice, current flow control valve assemblies require multiple valve cores to achieve synchronous left and right flow control, making the hydraulic system complex and costly. Furthermore, the high-pressure pilot flow control at both ends of the valve core switching mechanism in flow control valve assemblies can cause noise during steering in applications such as loaders and other construction machinery. Additionally, the pilot control of high-pressure flow can negatively impact steering comfort.

[0028] Therefore, how to simplify the flow control structure of the hydraulic system, reduce noise during steering, and improve the comfort of steering operation has become an urgent problem to be solved.

[0029] In this regard, embodiments of the present invention provide a steering hydraulic control system and engineering machinery, which can simplify the flow control structure of the hydraulic system, reduce noise generated during steering, and improve the comfort of steering operation.

[0030] like Figure 1 As shown, this invention discloses a hydraulic steering control system, which includes: an oil supply module 100, a flow control module 200, a direction control module 300, a steering cylinder 400, and a steering gear 500. The oil supply module 100 is used to pump hydraulic oil; the flow control module 200 is connected to the oil inlet of the oil supply module 100; the direction control module 300 is connected to the return oil inlets of both the flow control module 200 and the oil supply module 100; the steering cylinder 400 is connected to the oil inlet of the direction control module 300 and is used to perform steering operations based on the hydraulic oil supply; the steering gear 500 is connected to the pressure receiving ends of both the oil supply module 100 and the direction control module 300, and the direction control module 300 is also connected to the oil inlets of the steering gear 500 and the flow control module 300. The pressure receiving end of the control module 200 is connected to the oil circuit; the steering gear 500 is used to generate a pilot pressure signal based on the hydraulic oil; the direction control module 300 is used to control the hydraulic flow of the flow control module 200 to the steering cylinder 400, the pilot flow of the steering gear 500 to the pressure receiving end of the flow control module 200, and the return flow of the steering cylinder 400 to the oil supply module 100 based on the pilot pressure signal; the flow control module 200 is used to adjust the hydraulic flow output by the oil supply module 100 to the direction control module 300 based on the pilot pressure signal.

[0031] In this embodiment, the steering hydraulic control system is applied to construction machinery that uses hydraulic steering, including loaders, and the steering cylinder 400 is a cylinder used in construction machinery to perform steering actions.

[0032] The oil supply module 100 is connected to the flow control module 200 and the steering gear 500 via their respective oil circuits. The flow control module 200 is connected to the steering cylinder 400 via the steering control module 300. The oil outlet of the steering gear 500 is connected to the pressure receiving end of the steering control module 300 via its oil circuit, and is also connected to the pressure receiving end of the flow control module 200 via a pilot delivery pipe within the steering control module 300. This pilot delivery pipe is controlled by the steering control module 300 for opening and closing.

[0033] The oil supply module 100 pumps hydraulic oil to the flow control module 200 and the steering gear 500 through its pump port. The steering gear 500 converts the received hydraulic oil into a low-pressure pilot pressure signal, which is then applied to the pressure receiving end of the direction control module 300. This opens the pilot delivery pipeline within the direction control module 300 and connects the oil circuit between the flow control module 200 and the steering cylinder 400. Subsequently, the pilot delivery pipeline of the direction control module 300 is applied to the pressure receiving end of the flow control module 200, enabling the flow control module 200 to operate. Hydraulic oil then flows through the flow control module 200, the direction control module 300, and finally to the steering cylinder 400. The flow control module 200 adjusts the output hydraulic flow rate based on the magnitude of the pilot pressure signal, thereby controlling the hydraulic flow for left and right steering of the steering cylinder 400.

[0034] As can be seen, the steering hydraulic control system of the present invention can convert hydraulic pressure into a low-pressure pilot pressure signal through the steering gear 500, thereby realizing low-pressure pilot control of the flow control module 200, thereby reducing the noise generated during steering and improving the comfort of steering operation.

[0035] like Figure 2 As shown, in an optional embodiment, the direction control module 300 includes a direction control valve 310 and a direction control throttle orifice 320. The pilot feed port of the direction control valve 310 is connected to the oil circuits of the steering gear 500 and the pressure receiving end of the flow control module 200, respectively. The oil inlet of the direction control valve 310 is connected to the oil circuit of the outlet of the flow control module 200, the oil outlet of the direction control valve 310 is connected to the oil circuit of the steering cylinder 400, and the return feed port of the direction control valve 310 is connected to the oil circuit of the oil supply module 100. The direction control throttle orifice 320 is disposed in the oil circuit passage between the pressure receiving end of the direction control valve 310 and the steering gear 500. The direction control valve 310 is used to switch the valve core position according to the pilot pressure signal to control the hydraulic flow of the flow control module 200 to the steering cylinder 400, the pilot flow of the steering gear 500 to the pressure receiving end of the flow control module 200, and the return flow of the steering cylinder 400 to the oil supply module 100, respectively.

[0036] In this optional embodiment, refer to Figure 2 The steering gear 500 has two pilot flow output ports, A and B. The directional control valve 310 has two pressure receiving ends in the form of left and right spring chambers. The pilot flow output ports of the steering gear 500 are connected to the corresponding pressure receiving end of the directional control valve 310 via oil circuits. Each of the left and right pressure receiving ends of the directional control valve 310 is provided with a directional control throttle orifice 320 to achieve flow restriction. In the following embodiments, port A of the steering gear 500 is used as the pilot flow output port for illustration.

[0037] After the pilot pressure signal is output from port A of the steering gear 500, one path passes through the corresponding directional control throttle orifice 320 for flow restriction and acts on the pressure receiving end on the left side of the directional control valve 310, causing the valve core of the directional control valve 310 to switch to the left position. The other path is delivered to port e of the directional control valve 310. At this time, a flow path is formed between ports e and b of the directional control valve 310. That is, ports e and b act as pilot delivery ports, which can transmit the pilot pressure signal to the pressure receiving end of the flow control module 200, thereby controlling the flow control module 200 to adjust the output hydraulic flow. At the same time, a flow path is formed between ports a and f, and between ports g and d of the directional control valve 310. That is, port a acts as the oil inlet, port f as the oil outlet, and ports g and d as the oil return delivery ports. The flow output by the flow control module 200 can be output from ports a and f to the steering cylinder 400, and return to the oil supply module 100 through ports g and d. It is understandable that using port B of the steering gear 500 as the pilot flow output port does not affect the effect of this application. The only difference between the two is that the steering cylinder 400 controlled by them performs the opposite steering direction. That is, the operator can adjust the left and right steering actions by controlling the position of the valve core of the steering control valve 310 through the steering gear 500.

[0038] As can be seen, this optional embodiment can also adjust the flow circulation direction of the steering cylinder 400 through the directional control valve 310, thereby realizing the adjustment of left and right steering actions.

[0039] like Figure 2 As shown, in an optional embodiment, the flow control module 200 includes a flow control valve 210 and a pressure compensation unit 220. The inlet of the flow control valve 210 is connected to the pump port of the oil supply module 100, and the outlet of the flow control valve 210 is connected to the inlet of the directional control valve 310. The first and second pressure receiving ends of the flow control valve 210 are both connected to the pilot delivery port of the directional control valve 310. The pilot delivery port of the flow control valve 210 is connected to both the pilot delivery port of the directional control valve 310 and the second pressure receiving end of the flow control valve 210. The flow control valve 210 is used to adjust the hydraulic flow output by the oil supply module 100 to the inlet of the directional control valve 310 according to the pilot pressure signal. The pressure compensation unit 220 is connected to both the oil supply module 100 and the inlet of the flow control valve 210. The pressure receiving end of the pressure compensation unit 220 is connected to the pressure feedback port of the flow control valve 210. The pressure compensation unit 220 is used to compensate the hydraulic pressure of the flow control valve 210 according to the hydraulic pressure at its inlet.

[0040] In this optional embodiment, refer to Figure 2In the steering hydraulic control system, only one flow control valve 210 is needed for flow control. Port b of the directional control valve 310 is connected to the first pressure receiving end on the left side of the flow control valve 210, the second pressure receiving end on the right side of the flow control valve 210, and the oil circuit of port 3 of the flow control valve 210. Port 6 of the flow control valve 210 is connected to the second pressure receiving end on the right side of the flow control valve 210 and the oil circuit of port c of the directional control valve 310. The pump port of the oil supply module 100 is connected to port 1 of the flow control valve 210 and the oil circuit of the pressure compensation unit 220. Port 1 of the flow control valve 210 is also connected to the oil circuit of the pressure compensation unit 220. Port 2 of the flow control valve 210 is connected to the oil circuit of the pressure compensation unit 220. Port 4 of the flow control valve 210 is connected to the oil circuit of port a of the directional control valve 310.

[0041] When the valve core of the directional control valve 310 reverses and a flow path is formed between port e and port b of the directional control valve 310, one of the pilot pressure signals preferentially acts on the first pressure receiving end on the left side of the flow control valve 210, causing the valve core of the flow control valve 210 to switch to the left position.

[0042] At this time, a flow path is formed between port 1 of the flow control valve 210 and ports 2 and 4 respectively. That is, port 1 serves as the oil inlet and port 4 serves as the oil outlet to output hydraulic oil to port a of the directional control valve 310. Port 2 serves as the pressure feedback port to transmit the load pressure of the hydraulic oil to the pressure receiving end of the pressure compensation unit 220, thereby controlling the pressure compensation unit 220 to perform pressure compensation on port 1 of the flow control valve 210, so as to meet the hydraulic flow required by the core of the flow control valve 210.

[0043] like Figure 2 As shown, in an optional embodiment, the flow control module 200 further includes a first flow control throttle orifice 230 and a second flow control throttle orifice 240. The first flow control throttle orifice 230 is disposed in the oil passage between the first pressure receiving end of the flow control valve 210 and the pilot delivery port of the directional control valve 310; the second flow control throttle orifice 240 is disposed in the oil passage between the second pressure receiving end of the flow control valve 210 and the pilot delivery port of the directional control valve 310.

[0044] In this optional embodiment, refer to Figure 2The pilot pressure signal, output from port b of the directional control valve 310, is divided into three outputs. The first output flows through the first flow control orifice 230 and acts on the first pressure receiving end of the flow control valve 210. The second output flows through the second flow control orifice 240 and acts on the second pressure receiving end of the flow control valve 210. The third output flows directly to port 3 of the flow control valve 210. The first flow control orifice 230 and the second flow control orifice 240 can limit the flow of the pilot pressure signal output from port b of the directional control valve 310. Additionally, filters can be installed at the front and rear ends of the second flow control orifice 240.

[0045] like Figure 2 As shown, in an optional embodiment, the pressure compensation unit 220 includes: a priority valve 221, a first priority throttle orifice 222, a second priority throttle orifice 223, and a third priority throttle orifice 224. The inlet of the priority valve 221 is connected to the oil circuit of the oil supply module 100, the outlet of the priority valve 221 is connected to the oil circuit of the inlet of the flow control valve 210, the first pressure receiving end of the priority valve 221 is connected to the oil circuit of the outlet of the priority valve 221, and the second pressure receiving end of the priority valve 221 is connected to the oil circuits of the outlet of the priority valve 221 and the pressure feedback port of the flow control valve 210 respectively. The pressure compensation unit 220 is used to perform hydraulic pressure compensation on the flow control valve 210 according to the hydraulic pressure of the inlet of the flow control valve 210. The first priority throttling orifice 222 is provided in the oil circuit between the first pressure receiving end of the priority valve 221 and the outlet of the priority valve 221. The second priority throttling orifice 223 is provided in the oil circuit between the second pressure receiving end of the priority valve 221 and the outlet of the priority valve 221. The third priority throttling orifice 224 is provided in the oil circuit between the second pressure receiving end of the priority valve 221 and the pressure feedback port of the flow control valve 210.

[0046] In this optional embodiment, the oil supply module 100 is connected to the oil inlet of the priority valve 221, the oil outlet of the priority valve 221 is connected to the oil outlet of the flow control valve 210, the first pressure receiving end on the left side of the priority valve 221 is connected to the oil outlet of the priority valve 221 through the first priority throttling orifice 222, the second pressure receiving end on the right side of the priority valve 221 is connected to the oil outlet of the priority valve 221 through the second priority throttling orifice 223, and the second pressure receiving end on the right side of the priority valve 221 is also connected to the oil outlet of the flow control valve 210 through the third priority throttling orifice 224.

[0047] When the valve core of the flow control valve 210 is switched to the left position, a flow path is formed between port 1, port 2, and port 4 of the flow control valve 210. At this time, port 2 acts as a pressure feedback port, delivering the load pressure of the hydraulic oil to the second pressure receiving end of the priority valve 221, causing the valve core of the priority valve 221 to switch to the right position. This allows the oil supply module 100 to flow to port 1 of the flow control valve 210, thereby achieving pressure compensation for the flow control valve 210 and meeting the hydraulic flow required by the valve core of the flow control valve 210.

[0048] like Figure 2 As shown, in an optional embodiment, the steering hydraulic control system further includes: an overflow valve 610, a back pressure valve 620, a target check valve 630, and a replenishment control module 640. The inlet of the overflow valve 610 is connected to the pump port of the oil supply module 100, and the outlet of the overflow valve 610 is connected to the return port of the oil supply module 100. The inlet of the back pressure valve 620 is connected to the return delivery port of the directional control valve 310, and the outlet of the back pressure valve 620 is connected to the return port of the oil supply module 100. The inlet of the target check valve 630 is connected to the outlet of the overflow valve 610. The replenishment control module 640 is connected to the steering cylinder 400, the outlet of the target check valve 630, and the inlet of the back pressure valve 620, respectively.

[0049] In this optional embodiment, the inlet of the relief valve 610 is connected to the pump port of the oil supply module 100, the port 2 of the flow control valve 210, and the outlet of the priority valve 221, respectively. The outlet of the relief valve 610 is connected to the return port of the oil supply module 100. The relief valve 610 can preset the steering pressure threshold of the system. When the hydraulic pressure of the system exceeds the preset steering pressure threshold, the relief valve 610 is opened and the excess hydraulic oil flows back to the oil supply module 100 until the system hydraulic pressure is lower than the preset steering pressure threshold.

[0050] The inlet of the back pressure valve 620 and the outlet of the target check valve 630 are both connected to the oil circuit of the replenishment control module 640 and the d-port of the directional control valve 310. The outlet of the back pressure valve 620 and the inlet of the target check valve 630 are both connected to the oil circuit of the outlet of the relief valve 610. The replenishment control module 640 is connected to the oil circuit of the steering cylinder 400. When the steering cylinder 400 needs replenishment, the hydraulic flow direction restriction of the target check valve 630 and the back pressure valve 620 can direct the hydraulic oil originally used for return oil to the replenishment control module 640, and the replenishment operation of the steering cylinder 400 can be realized through the replenishment control module 640.

[0051] like Figure 2As shown, in an optional embodiment, the oil replenishment control module 640 includes: a first oil replenishment check valve 641, a first overload valve 642, a second oil replenishment check valve 643, and a second overload valve 644. The inlet of the first replenishing check valve 641 is connected to the outlet of the target check valve 630 and the return oil supply port of the directional control valve 310. The outlet of the first replenishing check valve 641 is connected to the first internal cavity oil circuit of the steering cylinder 400. The inlet of the first overload valve 642 is connected to the first internal cavity oil circuit of the steering cylinder 400. The outlet of the first overload valve 642 is connected to the inlet oil circuit of the back pressure valve 620. The inlet of the second replenishing check valve 643 is connected to the outlet of the target check valve 630 and the return oil supply port of the directional control valve 310. The outlet of the second replenishing check valve 643 is connected to the second internal cavity oil circuit of the steering cylinder 400. The inlet of the second overload valve 644 is connected to the second internal cavity oil circuit of the steering cylinder 400. The outlet of the second overload valve 644 is connected to the inlet oil circuit of the back pressure valve 620.

[0052] In this optional embodiment, the inlet of the first replenishing check valve 641 and the outlet of the first overload valve 642 are both connected to the oil circuit at the node between the outlet of the target check valve 630 and the inlet of the back pressure valve 620. The outlet of the first replenishing check valve 641 and the inlet of the first overload valve 642 are both connected to the oil circuit of the first inner cavity of the steering cylinder 400, where the first inner cavity is any one of the large or small cavities of the steering cylinder 400. When the steering cylinder 400 needs replenishment, hydraulic oil can flow through the first replenishing check valve 641 to replenish the first inner cavity of the steering cylinder 400; when the steering cylinder 400 experiences hydraulic pressure overload, the overloaded hydraulic oil can return to the oil supply module 100 through the first overload valve 642.

[0053] The inlet of the second replenishing check valve 643 and the outlet of the second overload valve 644 are both connected to the oil circuit at the node between the outlet of the target check valve 630 and the inlet of the back pressure valve 620. The outlet of the second replenishing check valve 643 and the inlet of the second overload valve 644 are both connected to the oil circuit of the second inner cavity of the steering cylinder 400, where the second inner cavity is another inner cavity among the large and small cavities of the steering cylinder 400. When the steering cylinder 400 needs replenishment, hydraulic oil can flow through the second replenishing check valve 643 to replenish the second inner cavity of the steering cylinder 400; when the steering cylinder 400 experiences hydraulic pressure overload, the overloaded hydraulic oil can return to the oil supply module 100 through the second overload valve 644.

[0054] like Figure 2As shown, in an optional embodiment, the steering hydraulic control system further includes a pressure reducing valve 650. The pressure reducing valve 650 is disposed between the pump port of the oil supply module 100 and the oil inlet of the steering gear 500. In this optional embodiment, the pressure reducing valve 650 can reduce the hydraulic pressure pumped by the oil supply module 100 to the steering gear 500 to a preset required pressure.

[0055] like Figure 2 As shown, in an optional embodiment, the oil supply module 100 includes a hydraulic oil tank 110 and a hydraulic pump 120. The hydraulic oil tank 110 is used to store hydraulic oil; the hydraulic pump 120 is connected to the hydraulic oil tank 110, the flow control module 200, and the steering gear 500 via oil circuits, and is used to pump the hydraulic oil in the hydraulic oil tank 110 to the flow control module 200 and the steering gear 500 respectively. In this optional embodiment, the hydraulic oil is stored in the hydraulic oil tank 110, and the hydraulic oil tank 110 is connected to the hydraulic pump 120 via oil circuits. Multiple hydraulic pumps 120 may be provided, and the priority valve 221 and the steering gear 500 are connected to the hydraulic pump 120 via ports P and P1 respectively. Figure 2 The diagram shows the hydraulic pump 120 oil circuit connection. Figure 2 The hydraulic pump 120 corresponding to port P2 is connected to port 1 of the flow control valve 210 to supply oil to the priority valve 221, the flow control valve 210 and the steering gear 500.

[0056] The present invention also discloses an engineering machinery, which includes an engineering machinery body and a steering hydraulic control system described in the above embodiments of the present invention, wherein the steering hydraulic control system is disposed in the engineering machinery body.

[0057] In this embodiment, the engineering machinery adopts the above-mentioned steering hydraulic control system, which can control the balance of left and right output flow by using only a flow control module 200 with a flow control valve 210, thereby simplifying the flow control structure of the hydraulic system and reducing system cost. At the same time, the hydraulic pressure is converted into a low-pressure pilot pressure signal through the steering gear 500, thereby realizing low-pressure pilot control of the flow control module 200, thereby reducing the noise generated during steering and improving the comfort of steering operation.

[0058] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A steering hydraulic control system, characterized in that, The steering hydraulic control system includes: The oil supply module is used to pump hydraulic oil; A flow control module, wherein the flow control module is connected to the oil circuit of the pump port of the oil supply module; A directional control module is connected to the return oil circuit of both the flow control module and the oil supply module. A steering cylinder is connected to the hydraulic circuit of the direction control module and is used to perform steering operations according to the hydraulic oil. The steering gear is connected to the oil supply module and the pressure receiving end oil circuit of the direction control module respectively, and the direction control module is also connected to the steering gear and the pressure receiving end oil circuit of the flow control module respectively. The steering gear is used to generate a pilot pressure signal based on the hydraulic oil. The direction control module is used to control the hydraulic flow of the steering cylinder by the flow control module, the pilot flow of the steering gear to the pressure receiving end of the flow control module, and the return flow of the steering cylinder to the oil supply module based on the pilot pressure signal. The flow control module is used to adjust the hydraulic flow output by the oil supply module to the direction control module based on the pilot pressure signal.

2. The steering hydraulic control system according to claim 1, characterized in that, The direction control module includes: A directional control valve, wherein the pilot feed port of the directional control valve is connected to the oil circuit of the pressure receiving end of the steering gear and the flow control module respectively, the oil inlet of the directional control valve is connected to the oil outlet of the flow control module, the oil outlet of the directional control valve is connected to the oil circuit of the steering cylinder, and the oil return feed port of the directional control valve is connected to the oil return port of the oil supply module. A directional control throttle orifice is provided in the oil passage between the pressure receiving end of the directional control valve and the steering gear; The directional control valve is used to switch the valve core position according to the pilot pressure signal, so as to control the hydraulic flow of the flow control module to the steering cylinder, the pilot flow of the steering gear to the pressure receiving end of the flow control module, and the return flow of the steering cylinder to the oil supply module.

3. The steering hydraulic control system according to claim 2, characterized in that, The flow control module includes: A flow control valve is provided, wherein the inlet of the flow control valve is connected to the pump port of the oil supply module, the outlet of the flow control valve is connected to the inlet of the directional control valve, the first pressure receiving end and the second pressure receiving end of the flow control valve are both connected to the pilot delivery port of the directional control valve, and the pilot delivery port of the flow control valve is connected to both the pilot delivery port of the directional control valve and the second pressure receiving end of the flow control valve. The flow control valve is used to adjust the hydraulic flow output by the oil supply module to the inlet of the directional control valve according to the pilot pressure signal. A pressure compensation unit is provided, which is connected to the oil supply module and the oil inlet of the flow control valve respectively. The pressure receiving end of the pressure compensation unit is connected to the pressure feedback port of the flow control valve. The pressure compensation unit is used to compensate the hydraulic pressure of the flow control valve according to the hydraulic pressure of the oil inlet of the flow control valve.

4. The steering hydraulic control system according to claim 3, characterized in that, The pressure compensation unit includes: A priority valve is provided, with its inlet connected to the oil supply module's oil circuit, its outlet connected to the inlet oil circuit of the flow control valve, its first pressure receiving end connected to the outlet oil circuit of the priority valve, and its second pressure receiving end connected to both the outlet oil circuit of the priority valve and the pressure feedback port oil circuit of the flow control valve. The pressure compensation unit is used to perform hydraulic pressure compensation on the flow control valve based on the hydraulic pressure at the inlet oil circuit of the flow control valve. The first priority throttling orifice is disposed in the oil line between the first pressure receiving end of the priority valve and the oil outlet of the priority valve. The second priority throttling orifice is disposed in the oil line between the second pressure receiving end of the priority valve and the oil outlet of the priority valve; The third priority throttling orifice is located in the oil line between the second pressure receiving end of the priority valve and the pressure feedback port of the flow control valve.

5. The steering hydraulic control system according to claim 3, characterized in that, The flow control module also includes: The first flow control throttle orifice is disposed on the oil passage between the first pressure receiving end of the flow control valve and the pilot delivery port of the directional control valve. The second flow control throttle orifice is disposed on the oil passage between the second pressure receiving end of the flow control valve and the pilot delivery port of the directional control valve.

6. The steering hydraulic control system according to claim 2, characterized in that, The steering hydraulic control system further includes: An overflow valve, wherein the oil inlet of the overflow valve is connected to the oil pump port of the oil supply module, and the oil outlet of the overflow valve is connected to the oil return port of the oil supply module. A back pressure valve, wherein the oil inlet of the back pressure valve is connected to the oil return supply port of the directional control valve, and the oil outlet of the back pressure valve is connected to the oil return port of the oil supply module. The target check valve has its inlet connected to the outlet of the relief valve. The oil replenishment control module is connected to the oil circuits of the steering cylinder, the oil outlet of the target check valve, and the oil inlet of the back pressure valve.

7. The steering hydraulic control system according to claim 6, characterized in that, The oil replenishment control module includes: The first replenishing check valve has its inlet connected to the outlet of the target check valve and the return oil supply port of the directional control valve, and its outlet is connected to the first inner cavity oil passage of the steering cylinder. The first overload valve has its inlet connected to the first internal cavity oil passage of the steering cylinder, and its outlet connected to the inlet oil passage of the back pressure valve. The second replenishing check valve has its inlet connected to the outlet of the target check valve and the return oil supply port of the directional control valve, and its outlet connected to the second inner cavity oil passage of the steering cylinder. The second overload valve has its inlet connected to the second inner cavity oil passage of the steering cylinder, and its outlet connected to the inlet oil passage of the back pressure valve.

8. The steering hydraulic control system according to any one of claims 1 to 7, characterized in that, The steering hydraulic control system further includes: A pressure reducing valve is provided between the oil pump port of the oil supply module and the oil inlet of the steering gear.

9. The steering hydraulic control system according to any one of claims 1 to 7, characterized in that, The oil supply module includes: A hydraulic oil tank, used to store hydraulic oil; A hydraulic pump is connected to the hydraulic oil tank, the flow control module, and the steering gear oil circuit, respectively. The hydraulic pump is used to pump the hydraulic oil in the hydraulic oil tank to the flow control module and the steering gear.

10. An engineering machinery, characterized in that, The engineering machinery includes: Construction machinery body; The steering hydraulic control system as described in any one of claims 1 to 9, wherein the steering hydraulic control system is disposed in the body of the engineering machinery.

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