Novel driving and energy recovery element

Abstract

The invention discloses a novel driving and energy recovery element, and belongs to the technical field of hydraulic transmission and control. An element main body is composed of a radial digital pump and a motor which are mutually independent and mechanically and coaxially connected, a plurality of rows of independent pistons and piston cavity units are arranged in a shell in the radial direction, and oil inlet and outlet are controlled by two groups of high-speed switch valves. The digital pump and the motor are rigidly connected through a concentric shaft with a plurality of rows of eccentric wheels, and a plurality of pistons and piston cavity units are radially arranged on the eccentric wheels; when the eccentric wheel drives the piston to reciprocate, pressure oil is supplied under a pump working condition; when pressure oil drives the piston to drive the concentric shaft to rotate, a motor working condition is achieved, and the eccentric wheel controls the pump-side piston and the motor-side piston to move. A motor side piston cavity communicates with a high-low pressure loop through a high-speed switch valve set, and hydraulic energy is converted into mechanical energy. And the pump side piston cavity is communicated with a low-pressure and load loop through another valve group to realize conversion from mechanical energy to pressure energy. The element coordinates the on-off time sequence of each valve group through the control unit to realize the functions of integrated driving and energy recovery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic transmission and control, in particular to a new type of driving and energy recovery element, and more particularly to a new type of hydraulic element which integrates a radial digital piston pump and a radial digital piston motor through a coaxial structure and adopts a high-speed digital valve group for collaborative control, thereby realizing the dual functions of driving and energy recovery. BACKGROUND

[0002] In a hydraulic system, efficient conversion of pressure and flow and energy recovery are the key to improving the overall energy efficiency of the system. Currently, the mainstream technical route adopts a highly integrated hydraulic transformer, but its structure and variable control are usually complex, and there are inherent problems such as inconvenient maintenance, heat concentration, and low design freedom. In addition, when using a hydraulic transformer to drive a load, the system's adjustment of pressure or flow often relies on a variable mechanism or a throttle valve. If a throttle valve is used for adjustment, although it can realize the transmission of pressure from high pressure to low pressure, it will be accompanied by significant throttling loss, reducing energy efficiency. The existing variable mechanism still has limitations in variable range and control stability, and the integrated hydraulic transformer also has room for further optimization in terms of design and distribution control of the flow area. These are technical problems that need to be solved in this field. SUMMARY

[0003] The technical problem to be solved by the present application is to overcome the technical defects of the existing integrated hydraulic transformer, such as difficult maintenance, low design freedom, and poor system collaboration and complex control after simply combining a discrete digital hydraulic pump and motor, and to provide a new type of driving and energy recovery element that is modular, high-performance, flexible in control, and high in energy efficiency.

[0004] To solve the above technical problems, the technical solution adopted by the present application is to provide a new type of driving and energy recovery element, the core of which is to integrate a radial digital piston pump module and a radial digital piston motor module through a mechanical series coaxial integration.

[0005] Further, the concentric shaft is supported on the transformer housing by a rolling bearing, and a plurality of eccentric wheels are arranged on the concentric shaft in the axial direction. Each eccentric wheel is radially arranged with a plurality of pistons. One end of the piston is in contact with the outer contour surface of the corresponding eccentric wheel and can reciprocate in the respective piston cavity under the drive of the eccentric wheel.

[0006] Furthermore, the component also includes a control unit and a valve group system composed of high-speed switching valves. The valve group system specifically includes: a motor-side high-speed switching valve group connected to each motor-side piston chamber, used to control the connection and disconnection of this chamber with the system's high-pressure or low-pressure circuit; and a pump-side high-speed switching valve group connected to each pump-side piston chamber, used to control the connection and disconnection of this chamber with the load's high-pressure working circuit or low-pressure oil source. The control unit is used to receive commands and sensor signals, and output control signals to synchronously coordinate the opening and closing sequence of the external power source driving the concentric shaft, the pump-side high-speed switching valve group, and the motor-side high-speed switching valve group.

[0007] Furthermore, the pump-side high-speed switching valve assembly is configured to connect to the low-pressure circuit when the volume of its corresponding piston chamber increases (suction stroke), and to the high-pressure load circuit when the volume decreases (discharge stroke). The motor-side high-speed switching valve assembly is configured to control its corresponding piston chamber to alternately connect to the high-pressure oil inlet circuit and the low-pressure oil return circuit according to actual operating conditions.

[0008] Furthermore, based on the above structure and control, the component of the present invention can realize two basic energy conversion modes: in motor operation, high-pressure oil drives the piston on the motor side to move, which drives the concentric shaft to rotate through the eccentric wheel, thereby outputting mechanical energy; in pump operation, external power drives the concentric shaft to rotate, which drives the piston on the pump side to move through the eccentric wheel, inputting oil from the low-pressure side to the high-pressure side, providing hydraulic power for the load.

[0009] Furthermore, to optimize torque characteristics, flow pulsation, and adapt to different functional modes, multiple rows of different eccentric wheels fixed on the same concentric shaft can be designed to have the phase relationship between their eccentric directions as in phase, out of phase, or with a fixed phase difference.

[0010] Furthermore, through the precise programming control of the valve group's on / off timing and the concentric shaft's drive state by the control unit, this component can realize a variety of advanced functions such as pressure-flow matching during the hydraulic system actuator (such as hydraulic cylinder, hydraulic motor) drive process, flow regeneration during downward movement, braking or gravitational potential energy recovery, thereby significantly improving system energy efficiency.

[0011] The beneficial effects of this invention are:

[0012] 1. High modularity and good maintainability: By designing the radial digital piston pump module and the radial digital piston motor module as relatively independent yet coaxially integrated modules, a clear modular structure is formed. This structure significantly simplifies the assembly and disassembly process, facilitates component testing, maintenance, and replacement, effectively reduces the total lifecycle cost, and improves system availability and maintainability.

[0013] 2. Smooth operation, high load-bearing capacity and reliability: Both the pump and motor adopt a multi-row radial piston structure, which multiplies the number of pistons working simultaneously, thereby significantly reducing flow and pressure pulsation and ensuring high stability of hydraulic and mechanical output. In addition, the inherent high pressure-bearing capacity of the radial piston structure, combined with the load-distributing effect of the multi-row arrangement, makes this component particularly suitable for high-pressure and heavy-load conditions, with high structural reliability.

[0014] 3. Precise control and fast dynamic response: Employing a fully digital flow distribution control strategy based on high-speed switching valves, it can directly and independently control the oil inlet and outlet actions of each piston chamber. Combined with precise adjustment of the drive concentric shaft speed, it can continuously, quickly, and programmably control the component's displacement, output pressure, and flow rate in real time, achieving excellent dynamic response performance and flexible adaptability to operating conditions.

[0015] 4. High degree of design freedom and great potential for system matching and optimization: Key parameters of the radial digital piston pump module and radial digital piston motor module (such as the number of piston rows, the number of pistons per row, and the piston diameter) can be independently designed and optimized according to the different pressure, flow rate, and power requirements of the high-pressure and low-pressure sides of the system. This flexibility allows for optimal matching between the pump side and the motor side, thereby achieving the optimization of the overall system efficiency over a wider operating range.

[0016] 5. Excellent thermal management performance and long service life: The pump module and motor module, as the main heat sources, are physically separated, which facilitates the dissipation of their respective heat. This design effectively avoids the problem of high heat concentration in traditional integrated transformers, reduces the thermal load on key components, thereby improving the overall thermal reliability of the components and helping to extend their service life.

[0017] 6. Highly integrated functions and high overall energy efficiency: The pump and motor are connected in series via a concentric shaft, and combined with independent digital flow distribution systems on both sides, multiple functions such as high-pressure drive, active pressure and flow conversion, braking energy or gravitational potential energy recovery (energy regeneration), and power compounding are efficiently integrated within a compact physical unit. This deep integration eliminates energy losses from complex external connecting pipelines and intermediate links, significantly improving the overall system energy efficiency from power source to actuator to energy recovery. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the novel drive and energy recovery element of the present invention.

[0020] Figure 2 This is a schematic diagram of application scheme 1 of the present invention.

[0021] Figure 3 This is a schematic diagram of application scheme 2 of the present invention.

[0022] 1. Concentric shaft; 2. Eccentric wheel; 3. Piston; 4. Piston chamber; 5. Oil tank; 6. High-speed switching valve; 7. Digital hydraulic transformer; 8. Return spring; 9. High-voltage accumulator; 10. Check valve; 11. Three-position four-way solenoid directional valve; 12. Hydraulic cylinder; 13. Hydraulic motor; 14. Throttle valve; 15. Low-voltage accumulator. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] See Figure 1 This example provides a specific implementation of a novel drive and energy recovery element.

[0026] This example consists of a digital hydraulic transformer 7, which is composed of a concentric shaft 1, an eccentric wheel 2 fixed on the concentric shaft 1, a piston 3 in contact with the eccentric wheel 2, a piston chamber 4 that accommodates the piston 3, a reset spring 8 that assists in resetting the piston 3, and a high-speed switching valve 6.

[0027] The concentric shaft 1 serves as the core transmission component, supported on the transformer housing by bearings at both ends. Multiple eccentric wheels 2 (or cam segments) are integrated on the concentric shaft 1. One end of the piston 3 contacts the outer surface of the eccentric wheel 2.

[0028] The valve system connected to the control unit includes: a motor-side high-speed switching valve connected to each motor piston chamber 4, used to control its connection to the high-pressure or low-pressure circuit of the component; and a pump-side high-speed switching valve connected to each pump piston chamber 4, used to control its connection to the load operating circuit. The control unit itself is used to receive commands and sensor signals, and output control signals to synchronously coordinate the drive source of the concentric shaft 1 and the actions of all pump-side and motor-side high-speed switching valves.

[0029] The pump-side high-speed switching valve allows piston chamber 4 to draw oil from the low-pressure circuit during the suction stroke and discharge oil to the high-pressure circuit during the discharge stroke; the motor-side high-speed switching valve controls piston chamber 4 to receive oil from the high-pressure circuit and discharge oil from the low-pressure circuit according to operating conditions.

[0030] The novel drive and energy recovery element, when the high-pressure oil in the high-pressure oil circuit drives the piston 3 to reciprocate in the piston chamber 4, the piston 3 drives the eccentric wheel 2 to rotate, which in turn drives the concentric shaft 1 to rotate to form a motor working condition; when the eccentric wheel 2 drives the piston 3 to reciprocate in the piston chamber 4, it becomes a pump working condition to supply pressure oil for driving the load.

[0031] See attached document Figure 2 This example provides an application scheme 1 for a novel drive and energy recovery element.

[0032] This example provides a complete hydraulic system integrating a digital hydraulic transformer, such as... Figure 2 As shown, the system includes: a digital hydraulic transformer 7, a high-voltage accumulator 9, a low-voltage accumulator 15, an oil tank 5, a concentric shaft 1, and an actuator (hydraulic cylinder 12 or hydraulic motor 13) controlled by a three-position four-way solenoid directional valve 11.

[0033] The core mechanical structure of the digital hydraulic transformer 7 includes: a concentric shaft 1, an eccentric wheel 2 fixed on the concentric shaft 1, a piston 3 in contact with the eccentric wheel 2, a piston cavity 4 accommodating the piston 3, and a reset spring 8 for the auxiliary reset piston 3.

[0034] Its working principle is as follows: The electric motor drives the concentric shaft 1 and the eccentric wheel 2 to rotate, forcing the piston 3 to reciprocate within the piston chamber 4. A high-frequency PWM (Pulse Width Modulation) signal is sent to the high-speed switching valve 6 via the control unit to precisely control its opening and closing sequence. When the piston 3 moves backward (increasing the chamber volume), the high-speed switching valve 6 connects the high-pressure accumulator 9 to the piston chamber 4, drawing in high-pressure oil. When the piston 3 moves forward (increasing the chamber volume), the high-speed switching valve 6 switches at a specific moment, connecting the piston chamber 4 to the low-pressure accumulator 15 or the load circuit, discharging the oil. By changing the duty cycle or phase of the PWM signal, the effective stroke and pressure of each oil discharge can be steplessly adjusted, thereby converting the constant pressure oil from the high-pressure accumulator 9 into working oil with the required pressure and flow rate to drive the hydraulic cylinder 12 or the hydraulic motor 13. The throttle valve 14 is used for system overload protection.

[0035] See attached document Figure 3 This example provides a novel application scheme 2 for drive and energy recovery elements.

[0036] This embodiment provides a hydraulic energy recovery system based on a digital hydraulic transformer, such as... Figure 3As shown, this system, based on the force control function of the first embodiment, adds the ability to actively recover the mechanical energy of external loads. When the load force is actively applied externally (e.g., when the boom of an engineering machine is lowering, a vehicle is braking, or a press is returning), the system can convert this mechanical energy into hydraulic energy and store it in the high-pressure accumulator 9, thus achieving energy saving and energy recovery.

[0037] The core components of the energy recovery system include: a digital hydraulic transformer 7, a high-voltage accumulator 9, a low-voltage accumulator 15, an oil tank 5, a three-position four-way solenoid directional valve 11, and a hydraulic cylinder 12. Its key feature is that the operating mode of the digital hydraulic transformer 7 can be switched by controlling the timing of its high-speed switching valve 6.

[0038] Energy recovery working principle: When an external load drives the piston of hydraulic cylinder 12 to move (for example, the load gravity forces the hydraulic cylinder piston rod to retract), the original working chamber is compressed to generate high-pressure oil, while the other chamber needs to be replenished with low-pressure oil. When the control unit detects that the direction of movement of the hydraulic cylinder is consistent with the direction of drive of the external load, it immediately switches the system from "force control mode" to "energy recovery mode".

[0039] Pressure Conversion and Energy Recovery: The high-pressure oil discharged from chamber A of the hydraulic cylinder is guided to a specific working port of the digital hydraulic transformer 7 via a three-position four-way solenoid directional valve 11. The control unit adjusts the control logic of the high-speed switching valve 6, enabling the digital hydraulic transformer 7 to operate under pump conditions (see the innovative principle section for the principle). At this time, the mechanical energy driven by the external load is converted into hydraulic energy (high-pressure oil) through the hydraulic cylinder and input into the digital hydraulic transformer 7.

[0040] The digital hydraulic transformer 7 operates as a "digital adjustable hydraulic motor-pump unit": it first acts as a hydraulic motor, using the input high-pressure oil to drive its internal rotor (concentric shaft 1) to rotate; simultaneously, its rotor also acts as a pump, drawing oil from the low-pressure accumulator 15 and discharging oil to the high-pressure accumulator 9. By precisely controlling the timing of the high-speed switching valves, the system can efficiently and controllably convert the fluctuating high pressure input from the load into a stable pressure level suitable for storage in the high-pressure accumulator 9. Ultimately, the mechanical energy of the external load is converted into hydraulic energy and stored in the high-pressure accumulator 9 for subsequent use.

[0041] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same embodiments / modes or examples. Furthermore, the specific features, structures, materials, or characteristics described may be present in one or more embodiments / modes or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of those different embodiments / modes or examples.

[0042] Furthermore, in the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A novel drive and energy recovery element characterized by: The application relates to a mechanical coaxial assembly of a concentric shaft, an eccentric wheel, a piston, a piston cavity, a high-speed switch valve group and a control unit, a radial digital piston pump and a radial digital piston motor; the concentric shaft is supported on a transformer shell through rolling bearings; a plurality of rows of eccentric wheels are arranged on the concentric shaft respectively, one end of the piston is in contact with the outer surface of the eccentric wheel profile, and the control element comprises a motor-side high-speed switch valve group connected with each motor piston cavity, a pump-side high-speed switch valve group connected with each pump piston cavity, and the control unit for receiving instructions and sensor signals and outputting control signals to synchronously coordinate the driving source of the concentric shaft and the actions of all the pump-side and motor-side high-speed switch valve groups.

2. The novel drive and energy recovery element of claim 1, characterized by: The pump-side high-speed switch valve group is configured to allow the piston cavity to suck oil from the low-pressure circuit in the oil suction stroke and discharge oil to the high-pressure circuit in the oil discharge stroke; the motor-side high-speed switch valve group is configured to control the piston cavity to suck oil from the high-pressure circuit and discharge oil from the low-pressure circuit according to the working condition requirement.

3. The novel drive and energy recovery element of claim 1, wherein: When the pressure oil of the high-pressure oil circuit drives the piston to reciprocate in the piston cavity, the piston drives the eccentric wheel to rotate, the concentric shaft is rotated to output mechanical energy and form the motor working condition; when the eccentric wheel drives the piston to reciprocate in the piston cavity, the pump working condition is formed to supply pressure oil for driving the load.

4. The novel drive and energy recovery element of claim 1, wherein: The eccentric wheels on the concentric shaft in the transformer shell are designed according to the eccentric direction and phase relationship of the concentric shaft according to the working condition; the eccentric wheels can be in-phase, anti-phase or have a fixed phase difference.

5. The novel drive and energy recovery element of claim 2, wherein: The novel driving and energy recovery element can be used in the driving of a linear actuator or a rotary actuator of a hydraulic transmission system to realize the pressure flow matching, flow regeneration or energy recovery of the load and the like.

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