CN115478572A - Engineering mechanical equipment and distributed electric hydrostatic hydraulic driving system thereof - Google Patents

Abstract

The application discloses engineering machine equipment and distributed electric hydrostatic drive system thereof, wherein, distributed electric hydrostatic drive system includes: a power subsystem, a power subsystem and an operation subsystem; the power subsystem includes a number of hydrostatic drive units, the hydrostatic drive units including: the system comprises a hydraulic cylinder, an energy accumulator, a driving pump, a medium container and an auxiliary pump; the energy accumulator, the active pump and the hydraulic cylinder form a driving loop so that the active pump can pump the hydraulic medium in the energy accumulator into different chambers of the hydraulic cylinder; the medium reservoir, the auxiliary pump and the hydraulic cylinder form a fluid-replenishing circuit so that the auxiliary pump can pump the hydraulic medium from the accumulator into different chambers of the hydraulic cylinder. The application has the beneficial effects that the engineering machinery equipment with the asymmetric structure of the hydraulic cylinder can be overcome, and the distributed electric hydrostatic driving system of the engineering machinery equipment is provided.

Description

Engineering mechanical equipment and distributed electric hydrostatic driving system thereof

Technical Field

The application relates to engineering machinery equipment and a distributed electro-hydrostatic driving system thereof.

Background

Construction machinery equipment, such as excavators, have long been in widespread use in a variety of capital construction fields. Owing to the characteristics of high power density, high rigidity, stability and the like of a hydraulic driving mode, the traditional hydraulic system (a dynamic hydraulic system) has high load capacity and high reliability and safety.

However, the conventional hydraulic system is a dynamic hydraulic transmission system, has a rather complex structure, and has the problems of high installation cost, hydraulic impact, pipeline loss, overheating caused by high-pressure throttling and particularly low energy efficiency. Meanwhile, the arrangement space of the structure and the maintenance difficulty of the system are increased by the long pipelines.

With the development of the hydrostatic transmission technology, in the related technology, for example, chinese patent document CN106013312A discloses an all-electric drive hydraulic excavator power system, which adopts a mode of converting electric energy into hydraulic energy to drive a hydraulic cylinder, so as to achieve the purposes of energy saving and emission reduction while continuing the high power advantage of the hydraulic system. But it only considers symmetric cylinders and is not applicable to asymmetric situations. For another example, chinese patent document CN110831750A discloses an electric hydrostatic drive device, which realizes two hydraulic structures of fast movement and boosting movement, but does not consider asymmetry and control of an actuator well, which may result in reduction of execution accuracy.

Aiming at the problem of asymmetric structure of a hydraulic cylinder in an electric hydrostatic driving excavator in the related art, an effective solution is not provided at present.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

Some embodiments of the present application provide a distributed electric hydrostatic drive system, comprising: the power supply subsystem is used for providing electric energy required by the electric hydrostatic driving system; a power subsystem for converting electrical energy into mechanical energy by driving or/and controlling the flow of a hydraulic medium; the operation subsystem is used for being operated by a user to realize the control of the power subsystem; the power subsystem includes a number of hydrostatic drive units, the hydrostatic drive units including: the system comprises a hydraulic cylinder, an energy accumulator, a driving pump, a medium container and an auxiliary pump; the energy accumulator, the active pump and the hydraulic cylinder form a driving loop so that the active pump can pump the hydraulic medium in the energy accumulator into different chambers of the hydraulic cylinder; the medium reservoir, the auxiliary pump and the hydraulic cylinder form a fluid circuit so that the auxiliary pump can pump the hydraulic medium in the accumulator into different chambers of the hydraulic cylinder.

Further, the hydrostatic drive unit further comprises: and a switching valve for switching the conduction state between the medium container and the hydraulic cylinder.

Further, a switching valve is provided between the medium container and the hydraulic cylinder.

Further, the switching valve at least comprises a three-position four-way electromagnetic directional valve.

Further, the hydrostatic drive unit further comprises: and the isolating device is used for forming a circulating loop isolated from the fluid infusion loop by the energy accumulator and the active pump.

Further, an isolation device is disposed between the active pump and the auxiliary pump.

Further, the isolation device at least comprises a two-position four-way electromagnetic directional valve.

Furthermore, the active pump is a bidirectional pump, and the auxiliary pump is a unidirectional pump.

Further, the hydrostatic drive unit includes a separate servo motor and controller.

As another aspect of the present application, the present application also provides a construction machinery equipment, which mainly comprises the above-mentioned distributed electric hydrostatic driving system.

The beneficial effect of this application lies in: the engineering mechanical equipment and the distributed electric hydrostatic driving system thereof are integrated and modularized, and can overcome the asymmetric structure of a hydraulic cylinder.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, serve to provide a further understanding of the application and to enable other features, objects, and advantages of the application to be more apparent. The drawings and their description illustrate the embodiments of the invention and do not limit it.

Further, throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic and that elements and elements are not necessarily drawn to scale.

In the drawings:

FIG. 1 is a schematic structural diagram of a work machine according to an embodiment of the present disclosure;

FIG. 2 is a block schematic diagram of a subsystem composition of an electric hydrostatic drive system in accordance with an embodiment of the present application;

FIG. 3 is a block diagram of a power subsystem according to an embodiment of the present application;

FIG. 4 is a block diagram of the module components of an operational subsystem according to one embodiment of the present application;

FIG. 5 is a block diagram schematic of an architecture of a power subsystem according to an embodiment of the present application;

FIG. 6 is a schematic illustration of a hydrostatic drive unit in the power sub-system in accordance with an embodiment of the present application;

FIG. 7 is a schematic structural view of an electric hydrostatic drive unit in accordance with another embodiment of the present application;

FIG. 8 is a schematic diagram of the operation of a hydrostatic drive unit in accordance with an embodiment of the present application;

FIG. 9 is a block diagram illustrating steps of a hydrostatic drive method according to one embodiment of the present application.

The reference numerals have the meanings:

100. engineering machinery equipment;

101. a power supply device; 102. an operating device; 103. a control device; 104. a wire harness assembly; 105. a liquid flow tube; 109. a movable arm; 110. a bucket rod; 111. a bucket;

106. a power subsystem; 107. a power subsystem; 108. an operating subsystem;

1061. a grid interface; 1062. a three-phase power supply; 1063. a power management module; 1064. a charging module; 1065. a battery; 1066. a voltage inverter;

1081. an interactive instruction interface; 1082. a boom handle; 1083. a dipper handle; 1084. a bucket handle;

200. a hydrostatic drive unit;

201. a hydraulic cylinder; 2011. a cylinder body; 2012. a piston; 2013. a piston rod; 201a, a first chamber; 201b, a second chamber; 201c, a first media channel; 201d, a second medium channel;

202. an accumulator;

203. an active pump; 203a and a first liquid outlet; 203b and a second liquid outlet;

204. a motor; 205. a controller;

206. a liquid supplementing device;

207. a media container; 208. an auxiliary pump; 209. a reflux valve;

210. a switching valve; a1, a first switching interface; a2, a second switching interface; a3, a third switching interface; a4, a fourth switching interface;

211. a first hydraulic control pressure reducing valve; b1, a first inlet; b2, a first outlet;

212. a second hydraulic pressure reducing valve; c1, a second inlet; c2, a second outlet;

213. a first hydraulic control check valve; d1, a first liquid inlet; d2, a first transfusion port; d3, a first hydraulic control port;

214. a second hydraulic control one-way valve; e1, a second liquid inlet; e2, a second infusion port; e3, a second hydraulic control port;

215. an isolation device; 216. an isolation valve; f1, a first isolation interface; f2, a second isolation interface; f3, a third isolation interface; f4, a fourth isolation interface;

217. a first pressure sensor; 218. a second pressure sensor; 219. a rotational speed sensor; 220. a speed sensor.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it is to be understood that the disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. It should be understood that the drawings and embodiments of the disclosure are for illustration purposes only and are not intended to limit the scope of the disclosure.

It should be noted that, for convenience of description, only the portions related to the related invention are shown in the drawings. The embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict.

It should be noted that the terms "first", "second", and the like in the present disclosure are only used for distinguishing different devices, modules or units, and are not used for limiting the order or interdependence of the functions performed by the devices, modules or units.

It is noted that references to "a", "an", and "the" modifications in this disclosure are intended to be illustrative rather than limiting, and that those skilled in the art will recognize that "one or more" may be used unless the context clearly dictates otherwise.

The names of messages or information exchanged between devices in the embodiments of the present disclosure are for illustrative purposes only, and are not intended to limit the scope of the messages or information.

The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Referring to fig. 1, the present application provides a work machine 100, particularly an excavator, the work machine 100 including: the hydraulic control system comprises a power supply device 101, a plurality of hydrostatic driving units 200a, 200b and 200c, a control device 102, a control device 103, an electric wiring harness assembly 104 and a liquid flow pipe 105.

In the case where the construction machine 100 is an excavator, the power supply device 101 is provided in a body portion (i.e., a portion where a cab is located) of the excavator, and is rotatable with respect to a chassis portion of the excavator along with the body portion.

The control means and control means 103 are also provided in the body part of the excavator for convenience of operation and routing of lines. The operation device is used for a driver (or an operator, the same below) to operate and provides an interactive interface for information display for the driver, namely, the interactive device is provided for the driver, so that the driver can control the excavator and can obtain corresponding operation information from the interactive interface.

As a specific solution, the operating device comprises a plurality of operating handles and corresponding operating mechanisms, and the handles are used for enabling a driver to generate corresponding operating instruction signals when operating in a swinging mode. Specifically, the operation handles include a boom swing handle 1082, an arm bucket handle 1083, and a travel handle pedal 1084. They are used to control a boom 109, an arm 110, and a bucket 111 of the excavator, swing, and travel, respectively.

As a specific scheme, the operation device further comprises an instrument, a display screen and the like to form an interactive interface. When the display screen adopts a touch screen, the functions of parameter input, target selection, state switching and the like can be realized at the same time.

The control device 103 is a device for converting an operation command signal of the operation device into a corresponding control command signal and transmitting the control command signal to the corresponding motor 204 or the solenoid valve, and meanwhile, the control device 103 can receive feedback signals of various sensor devices, thereby realizing functions such as signal processing, logical operation, control output and the like according to the feedback signals. Specifically, the control device 103 may include a plurality of controllers 205, and the controllers 205 may be configured by a single chip microcomputer, a DSP chip, or the like.

The hydrostatic drive unit 200 is provided in a working part of the excavator, i.e. a part that implements the excavating work, the working part (implement) specifically including: boom, stick, and bucket. The hydrostatic driving units are distributed, the three hydrostatic driving units 200 are respectively used for driving a movable arm, an arm and a bucket, and the three hydrostatic driving units are independently arranged on each actuator and are connected to the corresponding actuators through respective liquid flow pipes so as to reduce the loss of the pipelines to the maximum extent, reduce the redundancy of the pipelines, enable a single-cylinder system to be compact and improve the energy utilization rate. In addition, the hydrostatic drive unit is connected to a controller, a power supply, and the like via an electrical harness assembly.

The electrical harness assembly 104 is used to electrically connect various devices requiring power, and the electrical harness assembly 104 can be routed to a desired location of the excavator according to actual needs.

The fluid flow tube 105 is used to form a passage for the hydraulic medium, and the fluid flow tube 105 may be disposed at a position where the hydrostatic drive unit 200 is disposed, thereby achieving construction of the entire fluid transmission route.

Referring to FIG. 2, the hydrostatic drive system of the present application may be applied to a work machine such as the excavator shown in FIG. 1. From a system perspective, the apparatus in fig. 1 can be divided into three subsystems: a power subsystem 106, a power subsystem 107, and an operational subsystem 108. Namely, the hydrostatic drive system comprises: a power subsystem 106, a power subsystem 107, and an operational subsystem 108. Wherein the power subsystem 106 is used to provide the electrical power required by the hydrostatic drive system; the power subsystem 107 is used for converting electric energy into mechanical energy by driving or/and controlling the flow of the hydraulic medium; the operating subsystem 108 is operable by a user to effect control of the power subsystem 107.

Referring to fig. 3, as a specific solution, the power subsystem 106 includes: grid interface 1061, three-phase power 1062, power management module 1063, charging module 1064, battery 1065, and voltage inverter 1066. Power subsystem 106 is a source of energy, and in particular electrical energy, for the overall system, which provides the voltage required for operation of the overall system. The grid interface 1061 is used to couple power from the grid to the power subsystem 106. The three-phase power supply 1062 delivers three-phase ac power from the grid input to the power management module 1063 for direct use in providing power. The power management module 1063 may convert the ac power into dc power through the charging module 1064 to charge the battery 1065, so that the battery 1065 stores corresponding electric energy to maintain the power supply function of the power subsystem 106 when the grid interface 1061 does not have an external power source. The whole electric harness assembly 104 respectively uses alternating current and direct current to supply power for strong current and weak current equipment, so when the battery 1065 is used for supplying power, the direct current output by the battery 1065 needs to be converted into alternating current by the voltage inverter 1066 and transmitted to the power management module 1063, then the alternating current is subjected to voltage reduction and rectification by the power management module 1063, and strong current and weak current are output to the required equipment through the electric harness assembly 104. Of course, rather than merely carrying AC power, the electrical harness assembly 104 may carry DC power when control circuitry or the like, which is a low-current component, is used to effect electrical signal conduction.

As a specific solution, as shown in fig. 4, the operation subsystem 108 of the present application includes: an interactive instruction interface 1081, a boom swing handle 1082, a stick bucket handle 1083, and a travel handle pedal 1084. The interactive instruction interface 1081 is used for implementing a human-computer interaction function, and the boom swing handle 1082, the arm bucket 1083 and the walking handle pedal 1084 are all used for converting the user's operation into corresponding electrical signals. Control command signals generated by interface 1081, boom swing handle 1082, stick bucket 1083, and travel handle pedals 1084 are transmitted to the corresponding controller 205 or device via harness assembly 104. Accordingly, electrical harness assembly 104 provides the necessary electrical power to interface 1081, boom swing handle 1082, stick bucket 1083 and travel handle pedals 1084.

Alternatively, the input of some high-level control commands, including but not limited to level ground, hill repair, excavation, loading, etc., may be accomplished via input from the interactive command interface 1081. Safety control instructions can also be input through the interactive instruction interface 1081, and the safety control instructions include, but are not limited to, emergency stop and limit.

Specifically, as shown in fig. 5, the power subsystem 107 of the present application includes a plurality of hydrostatic drive units 200, each hydrostatic drive unit 200 configured to drive a particular implement (e.g., a hydraulic cylinder 201 that drives a boom, stick, and bucket). In the scheme shown in fig. 5, each hydrostatic drive unit 200 is provided with one controller 205 to realize control of the hydrostatic drive unit 200, and the controllers 205 realize coordinated control through the electric harness assembly 104 or are integrated into one general controller 205 to carry out coordinated control, so that the reliability is high, and even if one controller fails, the normal operation of other hydrostatic drive units is not influenced. Alternatively, different output ports of the integrated controller 205 may be used to control different hydrostatic drive units 200, respectively, in a compact and low cost manner.

As shown in fig. 6, a hydrostatic drive unit 200 mainly includes: hydraulic cylinder 201, accumulator 202, active pump 203, motor 204, controller 205, etc.

Specifically, the hydraulic cylinder 201 is used to realize power output; the hydraulic cylinder 201 comprises a cylinder 2011, a piston 2012 and a piston rod 2013, wherein the piston 2012 is accommodated in the cylinder 2011 and divides the internal space of the cylinder 2011 into a first chamber 201a and a second chamber 201b, the piston rod 2013 is connected to one side of the piston 2012, which is positioned in the second chamber 201b and can move synchronously with the piston 2012, and the piston rod 2013 is at least partially arranged outside the cylinder 2011. The accumulator 202 is at least used for storing hydraulic medium, and the accumulator 202 is communicated with an inlet of the active pump 203; the active pump 203 is used for pumping the hydraulic medium in the accumulator 202 into the hydraulic cylinder 201, the active pump 203 is a fixed displacement pump and at least has a first liquid outlet D2203a and a second liquid outlet 203b, the first liquid outlet D2203a is directly or indirectly connected to the first chamber 201a, and the second liquid outlet 203b is directly or indirectly connected to the second chamber 201b; the motor 204 is used for driving the active pump 203; the controller 205 is at least used for controlling the operation of the motor 204 (motor direction, rotation speed, etc.), the operation strategy of the hydraulic cylinder, flow balance, overload protection, precision control, etc.

Because the piston rod 2013 exists, the first chamber 201a and the second chamber 201b are in an asymmetric structure, so that the maximum volume of the first chamber 201a is larger than that of the second chamber 201b, the hydraulic cylinder 201 is an asymmetric hydraulic cylinder 201, and the inflow and outflow of the media of the first chamber 201a and the second chamber 201b are different when the piston 2012 moves, which results in instability when the piston rod 2013 is driven.

In order to solve the above problem of unstable driving of the piston rod 2013, the present application addresses the following starting points: when the oil is transferred from the first chamber 201a to the second chamber 201b, the oil flowing out of the first chamber 201a is larger than the oil flowing in of the second chamber 201b, the oil is redundant, and the redundant oil needs to be stored in the accumulator 202, and when the oil is transferred from the second chamber 201b to the first chamber 201a, the oil in the accumulator 202 needs to be supplemented to the first chamber 201a.

As a preferred solution, the hydrostatic drive unit 200 of the present application further includes: and a liquid replenishing device 206 for replenishing or recovering the hydraulic medium to one of the first chamber 201a or the second chamber 201b when the piston 2012 moves so as to balance the flow rate on both sides of the piston 2012. Specifically, the fluid replacement device 206 includes: medium tank 207, auxiliary pump 208, reflux valve 209, and switching valve 210.

As a concrete solution, the medium reservoir 207 is used to provide a fluid replacement space for accommodating the hydraulic medium separately from the accumulator 202. The auxiliary pump 208 has two modes of operation: a motor mode and a flow balance mode, when the auxiliary pump works in the motor mode, the hydraulic medium in the fluid infusion space is pumped into the first chamber 201a or the second chamber 201b; the auxiliary pump recovers the hydraulic medium to the fluid replacement space when it is operating in a flow balancing mode, i.e. when the flow is saturated in the first or second chamber or in the drive circuit. Specifically, the auxiliary pump 208 is a hydraulic pump that is driven by a low power motor (not shown). The return valve 209 is used to communicate the fluid replacement space with the first chamber 201a or the second chamber 201b when the pressure of the hydraulic medium input to the medium tank 207 is equal to or greater than a preset value. Specifically, the return valve 209 is a pilot operated relief valve. The switching valve 210 is at least used for switching the communication relationship between the first chamber 201a or the second chamber 201b and the auxiliary pump 208 and the return valve 209, and specifically, the switching valve 210 is a three-position four-way electromagnetic directional valve; the switching valve 210 is used to change positions to realize flow supplement/backflow to different oil passages, and realize active flow balance; the switch valve 210 is electrically connected to the controller 205, and the switch valve 210 is set by the electrical signal of the controller 205.

Specifically, the switching valve 210 includes: a first switching interface A1, a second switching interface A2, a third switching interface A3 and a fourth switching interface A4; the first switching port A1 is communicated with the first chamber 201a, the second switching port A2 is communicated with the second chamber 201b, the third switching port A3 is directly or indirectly communicated with the liquid supplementing space, and the fourth switching port is used for plugging. When the switching valve 210 is placed at the left position, the fluid infusion space is communicated with the second chamber 201b; when the switching valve 210 is set at the right position, the fluid infusion space is communicated with the first chamber 201 a; when the switching valve 210 is placed in the neutral position, the fluid infusion space is not communicated with the first chamber 201a and the second chamber 201b.

As a more specific aspect, the cylinder 2011 is provided with a first medium passage 201c that communicates with the first chamber 201 a; the fluid infusion device 206 further comprises: and a first pilot-operated relief valve 211, the first pilot-operated relief valve 211 being configured to make the first medium passage 201c constitute one-way communication to the switching valve 210 when the pressure of the first medium passage 201c is greater than a preset value. The first pilot-operated relief valve 211 includes: a first inlet B1 and a first outlet B2; the first inlet B1 is connected to the first chamber 201a, such that the pressure at the first inlet B1 is equal to the pressure of the first chamber 201a, the first outlet B2 is connected to the second chamber 201B, or the first outlet B2 is directly/indirectly connected to the active pump 203; when the pressure of the first chamber 201a is greater than the set pressure of the first pilot-controlled pressure reducing valve 211, the first outlet B2 of the first pilot-controlled pressure reducing valve 211 is opened, and the first pilot-controlled pressure reducing valve 211 is turned on, so that the pressure of the first chamber 201a is maintained in the safety pressure range.

The cylinder 2011 is provided with a second medium passage 201d communicating with the second chamber 201b; the fluid infusion device 206 further comprises: the second pilot-operated pressure reducing valve 212 is used to make the second medium passage 201d constitute one-way communication to the switching valve 210 when the pressure of the second medium passage 201d is greater than a preset value. The second hydraulic pressure reducing valve 212 includes: a second inlet C1 and a second outlet C2; the second inlet C1 is communicated to the second chamber 201b, so that the pressure at the second inlet C1 is equal to the pressure of the second chamber 201b, and the second outlet C2 is communicated to the first chamber 201a, or the second outlet C2 is directly/indirectly communicated to the active pump 203; when the pressure of the second chamber 201b is greater than the set pressure of the second hydraulic pressure reducing valve 212, the second outlet C2 of the second hydraulic pressure reducing valve 212 is opened, and the second hydraulic pressure reducing valve 212 is turned on, so that the pressure of the second chamber 201b is maintained in the safety pressure range.

As a more specific aspect, the hydrostatic drive unit 200 of the present application further includes: a first pilot check valve 213 and a second pilot check valve 214, wherein the first pilot check valve 213 is used for making the first liquid outlet 2023a form a one-way communication with the accumulator 202 when the pressure of the first liquid outlet 203a of the active pump 203 is greater than a preset value. Specifically, the first pilot operated check valve 213 includes: the device comprises a first liquid inlet D1, a first transfusion port D2 and a first hydraulic control port D3; the first fluid inlet D1 is connected to the first fluid outlet 203a of the active pump 203, the first fluid inlet D2 is connected to the accumulator 202, and the first fluid control port D3 is connected to the second fluid outlet 203b.

The second hydraulic check valve 214 is used for making the second liquid outlet 203b form one-way communication with the accumulator 202 when the pressure of the second liquid outlet 203b of the active pump 203 is greater than a preset value. Specifically, the second hydraulic check valve 214 includes: a second liquid inlet E1, a second transfusion port E2 and a second hydraulic control port E3; the second inlet port E1 is connected to the second outlet port 203b of the master pump 203, the second fluid delivery port is connected to the accumulator 202, and the second fluid control port E3 is connected to the first outlet port 203a.

With such a scheme, the first pilot check valve 213 and the second pilot check valve 214 are used for realizing flow balance between the first chamber 201a and the second chamber 201b, and since the pilot check valves can realize bidirectional conduction through the pilot control ports, pressure values of the first pilot check valve 213 and the second pilot check valve 214 are set to be equal in advance; when the pressure of the first chamber 201a exceeds a preset pressure value, the second hydraulic control port E3 is automatically opened to conduct the second hydraulic control check valve 214, so as to adjust the flow rate, thereby realizing the balance of the flow rates of the first chamber 201a and the second chamber 201b. Similarly, when the pressure of the second chamber 201b exceeds the preset pressure value, the first pilot control port D3 is automatically opened to conduct the first pilot control check valve 213, so as to adjust the flow rate, thereby achieving the balance between the flow rates of the first chamber 201a and the second chamber 201b.

As a preferred solution, the hydrostatic drive unit 200 of the present application further includes: a first pressure sensor 217, a second pressure sensor 218, a rotational speed sensor 219, and a speed sensor 220; the first pressure sensor 217 is used for monitoring the pressure of the first chamber 201a, and the first pressure sensor 217 is electrically connected with the controller 205 to output a pressure signal to the controller 205; the second pressure sensor 218 is used for monitoring the pressure of the second chamber 201b, and the second pressure sensor 218 is electrically connected with the controller 205 to output a pressure signal to the controller 205; the rotation speed sensor 219 is electrically connected to the controller 205 for monitoring the rotation speed of the motor 204. The speed sensor 220 is electrically connected to the controller 205 for monitoring the displacement and speed of the piston rod. Of course, the displacement sensor may be used to monitor the displacement of the piston rod, and the displacement and the velocity may be obtained by converting the displacement per unit time.

When the pressure value of the first pressure sensor 217 is greater than the pressure value of the second pressure sensor 218, and the monitoring value of the speed sensor 220 is smaller than a predetermined value (i.e., the pressure of the first chamber 201a is greater than the pressure of the second chamber 201 b), the switching valve 210 is set to the left position, and the fluid infusion space is communicated with the second chamber 201b; when the pressure value of the first pressure sensor 217 is smaller than the pressure value of the second pressure sensor 218 and the monitoring value of the speed sensor 220 is smaller than the predetermined value (i.e., the pressure of the second chamber 201b is greater than the pressure of the first chamber 201 a), the switching valve 210 is set to the right position, and the fluid infusion space is communicated with the first chamber 201a.

The switching valve 210, the auxiliary pump 208 and the return valve 209 realize active flow balance, the auxiliary pump 208 has the functions of outputting flow and recovering flow, the return valve 209 is conducted when the pressure reaches a preset value, and the oil path flow can return to the oil tank through the return valve 209.

The oil tank is provided as a specific example of the medium container 207. The medium tank 207, the auxiliary pump 208, the return valve 209, and the switching valve 210 described above constitute the fluid replacement device 206 of the present application. The fluid replenishing device 206 of the present application is used for replenishing the hydraulic medium to one of the first chamber 201a or the second chamber 201b when the piston 2012 moves so as to balance the flow balance on both sides of the piston 2012.

The hydrostatic drive unit 200 of the present application operates with four operating conditions:

the working condition I is as follows: when the pressure of the second chamber 201b is lower than that of the first chamber 201a, the piston rod 2013 moves towards the second chamber 201b; the controller 205 controls the motor 204 to drive the active pump 203, so that the oil in the second chamber 201b is delivered to the first chamber 201a through the active pump 203. The direction of the second hydraulic pressure is the same as the direction of the movement speed of the piston rod 2013, the inlet flow of the first chamber 201a is larger than the discharge flow of the second chamber 201b, the pressure value of the first pressure sensor 217 is larger than the pressure value of the second pressure sensor 218, the switching valve 210 is arranged at the left position, the second hydraulic control port E3 is opened, the second hydraulic control one-way valve 214 is conducted, the oil in the accumulator 202 and the oil led out by the auxiliary pump 208 are converged into the oil flowing out of the second chamber 201b, and the flow returning to the active pump 203 is equal to the output flow.

Working conditions are as follows: when the pressure in the second chamber 201b is higher than that in the first chamber 201a, the piston rod 2013 moves towards the second chamber 201b; the controller 205 controls the motor 204 to drive the active pump 203, so as to deliver the oil in the second chamber 201b to the first chamber 201a through the active pump 203, wherein the pressure direction is opposite to the moving speed direction of the piston rod 2013, and at this time, the oil led out by the accumulator 202 and the auxiliary pump 208 is also required to supplement the first chamber 201a. The pressure value of the first pressure sensor 217 is smaller than that of the second pressure sensor 218, the switching valve 210 is arranged at the right position, the first hydraulic control port D3 is opened, the first hydraulic control one-way valve 213 is conducted, oil in the energy accumulator 202 and oil led out by the auxiliary pump 208 converge to the first chamber 201a, flow balance between the first chamber 201a and the second chamber 201b is achieved, potential energy of a load is transmitted to the piston 2012, the hydraulic circuit drives the active pump 203 to generate power, the power is recycled, and energy is saved.

Working conditions are as follows: the pressure of the second chamber 201b is higher than that of the first chamber 201a, and the piston rod 2013 moves towards the first chamber 201 a; at this time, the oil in the first chamber 201a is transferred to the second chamber 201b by the active pump 203. The pressure direction is the same as the moving speed direction of the piston rod 2013, the outflow flow of the first chamber 201a is larger than the inflow flow of the second chamber 201b, the pressure value of the first pressure sensor 217 is smaller than the pressure value of the second pressure sensor 218, the switching valve 210 is arranged at the right position, the first hydraulic control port D3 is opened, the first hydraulic control one-way valve 213 is conducted, the redundant oil in the first chamber flows into the oil tank from the switching valve 210 and the auxiliary pump, the auxiliary pump is driven to generate electricity and is recycled, and energy is saved; meanwhile, a part of the redundant oil in the first chamber flows into the accumulator 202 from the first pilot-controlled check valve 213, and the flow balance between the first chamber 201a and the second chamber 201b is realized.

Working conditions are as follows: the pressure of the second chamber 201b is lower than that of the first chamber 201a, and the piston rod 2013 moves towards the first chamber 201 a; the oil in the first chamber 201a is delivered to the second chamber 201b by the active pump 203. The pressure direction is opposite to the movement speed direction of the piston rod 2013, the outflow flow of the first chamber 201a is larger than the inflow flow of the second chamber 201b, the pressure value of the first pressure sensor 217 is larger than the pressure value of the second pressure sensor 218, the switching valve 210 is arranged at the left position, the second hydraulic control port E3 is opened, the second hydraulic control one-way valve 214 is conducted, and redundant oil liquid which is about to enter the second chamber 201b flows into the oil tank through the switching valve 210 and the auxiliary pump, so that the auxiliary pump is driven to generate electricity and is recycled, and energy is saved; meanwhile, a part of the redundant oil in the second chamber 201b flows into the accumulator 202 through the second pilot-controlled check valve 214, so that the flow balance between the first chamber 201a and the second chamber 201b is realized. Meanwhile, the potential energy of the load is transmitted to the piston 2012, and then the driving pump 203 is driven by the hydraulic loop to generate electricity and be recycled, so that the energy is saved.

Based on in the operating mode above, the quiet hydraulic drive unit of this application can realize the variable displacement control to asymmetric jar, and first, the second hydraulic control relief pressure valve, the auxiliary pump, the active pump, the energy storage ware has all played energy recuperation's effect in the course of the work, has optimized the system energy consumption for the quiet hydraulic drive unit of this application possesses low energy consumption characteristic (energy recuperation, overflow optimization).

As further shown in fig. 6, in an implementation, the hydrostatic drive unit 200 further includes an isolation device 215, the isolation device 215 isolating communication between the first outlet port 203a or/and the second outlet port 203b of the active pump 203 and the first chamber 201a or/and the second chamber 201b.

Specifically, the first liquid outlet 203a and the second liquid outlet 203b of the active pump 203 are respectively connected to an isolation device 215, and the isolation device 215 at least comprises an isolation valve 216; the isolation valve 216 is electrically connected with the controller 205, and the isolation valve 216 changes setting by receiving an electric signal of the controller 205, so that the oil circuit of the hydraulic cylinder 201 and the active pump 203 is switched on and off, and the sliding caused by the leakage of the active pump 203 is avoided. Meanwhile, the hydraulic impact effect of the driving circuit under the condition of sudden load change is prevented, and the element safety of the driving circuit is ensured under the conditions of sudden stop, rapid unloading, loading obstacle and the like.

Specifically, the isolation valve 216 is a two-position four-way electromagnetic directional valve capable of isolating the communication between the fluid infusion device 206 and the accumulator 202. The isolation valve 216 includes a first isolation port F1, a second isolation port F2, a third isolation port F3, and a fourth isolation port F4; the first isolation port F1 is connected to the first outlet 203a of the active pump 203, the second isolation port F2 is connected to the second outlet 203b of the active pump 203, the third isolation port F3 is connected to the first chamber 201a, and the fourth isolation port F4 is connected to the second chamber 201b. When the isolation valve 216 is switched to the first setting, the first isolation port F1 is communicated to the third isolation port F3 along the internal passage of the isolation valve 216, so that the first liquid outlet 203a is communicated with the first chamber 201 a; when the isolation valve 216 is switched to the second set position, the first isolation port F1 is communicated to the second isolation port F2 along the internal passage of the isolation valve 216, the oil paths of the third isolation port F3 and the fourth isolation port F4 are switched on and off, and the switching valve 210 is placed in the neutral position at the moment, so that the hydraulic media in the first chamber 201a and the second chamber 201b cannot flow in and out, and the position of the piston rod 2013 can be stably maintained.

As shown in fig. 7, as another embodiment of the isolation device, the isolation device 315 includes an isolation valve 316 and a shuttle valve 317, the isolation valve 216 is electrically connected to the controller 205, and the isolation valve 216 is changed in setting by an electrical signal from the controller 205, so as to open and close the oil paths between the hydraulic cylinder 201 and the active pump 203, and avoid the sliding caused by the leakage of the active pump 203.

In the normal working process, the shuttle valve 317 is opened at one side of the high-pressure area to act on the isolation valve 316 hydraulic control unit, at the moment, the pressure is regulated through the electric control side of the isolation valve 316, and the isolation valve 316 is normally opened and is positioned at the upper position.

When the hydraulic impact effect occurs, the high-pressure side pressure of the driving circuit is sharply increased, the high-pressure side pressure acts on the isolating valve hydraulic control unit, the isolating valve is closed and is positioned at the lower position, and the driving circuit is isolated, so that the driving pump, the motor and the energy accumulator are protected. Meanwhile, the hydraulic cylinder is limited, the stability and the precision of the hydraulic cylinder are guaranteed, and accidents caused by high-amplitude vibration are prevented.

When the pressure is over, the isolating valve is opened by the controller acting on the electromagnetic signal unit, and the normal work of the loop is recovered.

The application is further based on the scheme, and a method for arranging the distributed electric hydrostatic system of the engineering machinery equipment is provided. Each hydrostatic drive unit 200 is all integrated modularization, and each hydrostatic drive unit 200 can be integrated as an independent equipment, when the hydrostatic drive system of this application is being built, can lay the hydrostatic drive unit 200 that integrates through the modularized mode according to demand and engineering machine tool's demand to reduce the redundancy of pipeline, made single cylinder system become compact, improved energy utilization.

As one particular example, boom and stick cylinder hydrostatic drive units 200a and 200b are disposed near the boom surface cylinder and bucket cylinder hydrostatic drive unit 200c is disposed near the stick surface bucket cylinder, which is coupled to control signal harness and power management module 1064 via harness assembly 104 and to cylinder 201 via fluid line 105.

As a specific solution, each hydrostatic drive unit 200 may be integrated with a controller 205, a drive motor 203, a bidirectional constant displacement pump 203, an accumulator 202, a one-way control valve 213 (214), an isolation device 215, a pressure control valve 211 (212), a three-position four-way directional valve (210), an auxiliary pump (208), a flow valve (209), and a media reservoir.

As shown in fig. 8, from the control point of view, in the hydrostatic unit, the controller 205 actively controls the active pump 203 and the auxiliary pump 208, and at the same time, the corresponding sensors feed back electric signals to the controller 205 regarding the relevant states of the hydraulic cylinder 201, thereby forming a closed control loop.

The controller 205 base control method uses a closed loop velocity displacement control. The controller 205 is connected to the harness assembly 104 to read command signals sent by the system regarding the speed, displacement or other function of the hydraulic cylinder 201, and then to control the motor 204 (preferably the servo motor 204) based on these command signals.

Specifically, the active pump is driven by a high power motor and the auxiliary pump is driven by a low power motor. The hydraulic cylinder 201 is driven to move by the driving circuit.

The signals required to be output by the sensors include two chamber pressure signals of the hydraulic cylinder 201 and a displacement signal of the piston rod 2013. And processing the speed signal and the displacement signal based on a filtering means, and realizing the control of the position and the speed by designing a control strategy, wherein the control mode comprises the steps of not limited to PID control, sliding film control, robust control and the like.

On the other hand, the displacement, the speed signal and the pressure signal are used for judging the structure of the driving loop, so that an intelligent active flow balance strategy, a start-stop strategy and a hydraulic cylinder 201 telescopic switching strategy are realized.

Specifically, when an actuator drive signal is detected, the controller 205 acts on the isolation valve 216 of the drive circuit to communicate the drive circuit with the power circuit. The isolation valve 216 of the drive circuit is closed after no drive signal and the target position is reached.

The controller 205 is designed to determine the load condition through pressure acquisition. When a tensile load is detected and the hydraulic cylinder 201 is in tensile output, the controller 205 switches the switching valve 210 of the balance circuit to a left functional position to establish a path between a main pump (the abbreviation of the main pump 203, the same below), an auxiliary pump (the abbreviation of the auxiliary pump 208, the same below) and an oil inlet of the main pump, and oil is supplemented to the oil inlet of the main pump to realize flow balance; when a tensile load is detected and the hydraulic cylinder 201 is in compression output, the controller 205 switches the switching valve 210 of the balance loop to a left functional position to establish a passage between the oil outlets of the auxiliary pump and the main pump, and performs flow diversion on the oil outlet of the main pump to realize flow balance; when a compression load is detected and the hydraulic cylinder 201 is in tension output, the controller 205 switches the switching valve 210 of the balance loop to a right functional position to establish a passage between the oil outlets of the auxiliary pump and the main pump and supplement oil to the oil outlet of the main pump to realize flow balance; when a compression load is detected and the hydraulic cylinder 201 is in compression output, the controller 205 switches the switching valve 210 of the balance circuit to the right functional position to establish a passage between the auxiliary pump and the main pump oil inlet, and performs flow diversion on the main pump oil inlet to realize flow balance.

When receiving the emergency stop signal, the controller 205 controls the isolation valve 216 of the driving circuit and the switching valve 210 of the balancing circuit to cut off the oil paths between the driving circuit and the power circuit and between the driving circuit and the balancing circuit. While minimizing the output of the servo motor 204 to achieve the standby energy-saving control mode.

The pressure of the pressure reducing valve of the balancing circuit is set according to actual conditions. So as to ensure that the equal volume unloading is realized under the condition of flow diversion of the balance loop.

Other functional signals include, but are not limited to, an emergency stop signal, a limit signal, and the like. The controller 205 may be one controller, and is connected to multiple servo motor 204 driving circuits to control the movement of the hydraulic cylinder 201, or may be distributed multiple controllers, and is respectively connected to corresponding servo motor 204 driving circuits to control the movement of the hydraulic cylinder 201.

As another aspect of the present application, the present application is also based on the above, and provides an electric hydrostatic driving method. The electric hydrostatic drive method of the present application is performed by the hydrostatic drive unit 200 described above.

Specifically, in the hydrostatic drive unit 200, the accumulator 202, the master pump 203 and the hydraulic cylinder 201 form a drive circuit so that the master pump 203 can pump the hydraulic medium in the accumulator 202 into different chambers of the hydraulic cylinder 201; the medium reservoir 207, the auxiliary pump 208 and the hydraulic cylinder 201 form a fluid circuit so that the auxiliary pump 208 can pump the hydraulic medium in the accumulator 202 into different chambers of the hydraulic cylinder 201;

based on the above, as shown in fig. 9, the electro-hydrostatic driving method includes the steps of:

s1: driving the active pump 203 to pump hydraulic medium into one chamber 201a or 201b of the hydraulic cylinder 201;

s2: detecting the pressure value of the hydraulic medium in the other chamber 201b or 201a of the hydraulic cylinder 201;

s3: the operation of the auxiliary pump 208 is controlled on the basis of the pressure value of the hydraulic medium in the other chamber of the hydraulic cylinder 201.

As a specific scheme, step S2 may also detect the speed and displacement value of the piston rod, or detect the pressure values of the two chambers at the same time, and then step S3 combines the pressure value of the hydraulic medium in the other chamber and the speed and displacement value of the piston rod to control the operation of the auxiliary pump.

As a specific solution, a switching valve 210 is provided in the hydrostatic drive unit 200, which is arranged between the medium reservoir 207 and the hydraulic cylinder 201; the electro-hydrostatic drive method further includes the steps of: the switching valve 210 is controlled according to the pressure value of the hydraulic medium in the hydraulic cylinder 201 to switch the conduction state between the medium tank 207 and the hydraulic cylinder 201.

Specifically, an isolator 215 is provided in the hydrostatic drive unit 200; the electro-hydrostatic drive method further includes the steps of: the accumulator 202 and the active pump 203 form a circulation loop isolated from the fluid replenishing loop by controlling the isolation device 215 according to the pressure values of the hydraulic medium in the two chambers of the hydraulic cylinder 201 and the position of the piston rod 2013.

As a specific scheme, step S3 is to control the operation of the auxiliary pump, the switching valve and the isolation valve according to the pressure values of the first chamber and the second chamber and the displacement and velocity values of the piston rod. And calculating a speed signal and a displacement signal based on a filtering means, and realizing the control of the position and the speed by designing a control strategy, wherein the control mode comprises the steps of not limited to PID control, sliding film control, robust control and the like. Other functional signals include, but are not limited to, emergency stop signals, limit signals, and the like.

As an embodiment of the specific scheme, the working process includes four control strategies:

the first strategy is as follows: when the pressure of the second chamber 201b is lower than that of the first chamber 201a, the piston rod 2013 moves towards the second chamber 201b; the controller 205 controls the motor 204 to drive the active pump 203, so that the oil in the second chamber 201b is delivered to the first chamber 201a through the active pump 203. The direction of the second hydraulic pressure is the same as the direction of the movement speed of the piston rod 2013, the inlet flow of the first chamber 201a is larger than the discharge flow of the second chamber 201b, the pressure value of the first pressure sensor 217 is larger than the pressure value of the second pressure sensor 218, the switching valve 210 is arranged at the left position, the second hydraulic control port E3 is opened, the second hydraulic control one-way valve 214 is conducted, the oil in the accumulator 202 and the oil led out by the auxiliary pump 208 are converged into the oil flowing out of the second chamber 201b, and the flow returning to the active pump 203 is equal to the output flow.

And (2) strategy two: when the pressure in the second chamber 201b is higher than that in the first chamber 201a, the piston rod 2013 moves towards the second chamber 201b; the controller 205 controls the motor 204 to drive the active pump 203, so as to deliver the oil in the second chamber 201b to the first chamber 201a through the active pump 203, wherein the pressure direction is opposite to the moving speed direction of the piston rod 2013, and at this time, the oil led out by the accumulator 202 and the auxiliary pump 208 is also required to supplement the first chamber 201a. The pressure value of the first pressure sensor 217 is smaller than that of the second pressure sensor 218, the switching valve 210 is arranged at the right position, the first hydraulic control port D3 is opened, the first hydraulic control one-way valve 213 is conducted, oil in the energy accumulator 202 and oil led out by the auxiliary pump 208 converge to the first chamber 201a, flow balance between the first chamber 201a and the second chamber 201b is achieved, potential energy of a load is transmitted to the piston 2012, the hydraulic circuit drives the active pump 203 to generate electricity and recycle the electricity, and energy is saved.

And (3) strategy three: the pressure of the second chamber 201b is higher than that of the first chamber 201a, and the piston rod 2013 moves towards the first chamber 201 a; the oil in the first chamber 201a is delivered to the second chamber 201b by the active pump 203. The pressure direction is the same as the moving speed direction of the piston rod 2013, the outflow rate of the first chamber 201a is larger than the inflow rate of the second chamber 201b, the pressure value of the first pressure sensor 217 is smaller than the pressure value of the second pressure sensor 218, the switching valve 210 is arranged at the right position, the first hydraulic control port D3 is opened, the first hydraulic control one-way valve 213 is conducted, the redundant oil in the first chamber flows into the oil tank from the switching valve 210 and the auxiliary pump, the auxiliary pump is driven to generate electricity and is recycled, and energy is saved; meanwhile, a part of the redundant oil in the first chamber flows into the accumulator 202 from the first pilot-controlled check valve 213, so that the flow balance between the first chamber 201a and the second chamber 201b is realized.

And (4) strategy four: the pressure of the second chamber 201b is lower than that of the first chamber 201a, and the piston rod 2013 moves towards the first chamber 201 a; the oil in the first chamber 201a is delivered to the second chamber 201b by the active pump 203. The pressure direction is opposite to the moving speed direction of the piston rod 2013, the outflow flow of the first chamber 201a is larger than the inflow flow of the second chamber 201b, the pressure value of the first pressure sensor 217 is larger than the pressure value of the second pressure sensor 218, the switching valve 210 is arranged at the left position, the second hydraulic control port E3 is opened, the second hydraulic control one-way valve 214 is conducted, and redundant oil to enter the second chamber 201b flows into the oil tank through the switching valve 210 and the auxiliary pump, so that the auxiliary pump is driven to generate electricity and is recycled, and energy is saved; meanwhile, a part of the redundant oil in the second chamber 201b flows into the accumulator 202 through the second pilot-controlled check valve 214, so that the flow balance between the first chamber 201a and the second chamber 201b is realized. Meanwhile, the potential energy of the load is transmitted to the piston 2012, and then the driving pump 203 is driven by the hydraulic loop to generate electricity and be recycled, so that the energy is saved.

The foregoing description is only exemplary of the preferred embodiments of the disclosure and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the invention in the embodiments of the present disclosure is not limited to the specific combinations of the above-mentioned features, and other embodiments in which the above-mentioned features or their equivalents are combined arbitrarily without departing from the spirit of the invention are also encompassed. For example, the above features and (but not limited to) the features with similar functions disclosed in the embodiments of the present disclosure are mutually replaced to form the technical solution.

Claims (10)

1. A distributed electric hydrostatic drive system, comprising:

the power supply subsystem is used for providing electric energy required by the distributed electric hydrostatic driving system;

a power subsystem for converting electrical energy into mechanical energy by driving or/and controlling the flow of a hydraulic medium;

the operation subsystem is used for being operated by a user to realize the control of the power subsystem;

the method is characterized in that:

the power subsystem includes a number of hydrostatic drive units, including: the system comprises a hydraulic cylinder, an energy accumulator, a driving pump, a medium container and an auxiliary pump;

the energy accumulator, the active pump and the hydraulic cylinder form a driving loop so that the active pump can pump the hydraulic medium in the energy accumulator into different chambers of the hydraulic cylinder;

the medium reservoir, the auxiliary pump and the hydraulic cylinder form a fluid circuit so that the auxiliary pump can pump the hydraulic medium in the accumulator into different chambers of the hydraulic cylinder.

2. The distributed electric hydrostatic drive system of claim 1, wherein:

the hydrostatic drive unit further includes:

and a switching valve for switching the conduction state between the medium container and the hydraulic cylinder.

3. The distributed electric hydrostatic drive system of claim 2, wherein:

the switching valve is disposed between the medium container and the hydraulic cylinder.

4. The distributed electric hydrostatic drive system of claim 3, wherein:

the switching valve at least comprises a three-position four-way electromagnetic directional valve.

5. The distributed electric hydrostatic drive system of claim 4, wherein:

the hydrostatic drive unit further includes:

and the isolating device is used for forming a circulating loop isolated from the fluid infusion loop by the energy accumulator and the active pump.

6. The distributed electric hydrostatic drive system of claim 5, wherein:

the isolation device is disposed between the active pump and the auxiliary pump.

7. The distributed electric hydrostatic drive system of claim 6, wherein:

the isolating device at least comprises a two-position four-way electromagnetic directional valve.

8. The distributed electric hydrostatic drive system of any of claims 1-7, wherein:

the active pump is a bidirectional pump, and the auxiliary pump is a unidirectional pump.

9. The distributed electric hydrostatic drive system of claim 8, wherein:

the hydrostatic drive unit includes a separate servo motor and controller.

10. A work machine rig comprising the distributed electric hydrostatic drive system of any of claims 1-9.

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