CN115126739B - Composite type attenuation device for digital valve group pressure pulsation and test method thereof - Google Patents

Abstract

The invention provides a composite type attenuation device facing to pressure pulsation of a digital valve bank and a testing method thereof. The first end of the neck connecting piece is connected with the first end of the lining cavity outer shell, the mounting end of the lining cavity inner lining is connected with the second end of the lining cavity outer shell, and the mounting end of the lining cavity top cover is connected with the third end of the lining cavity outer shell. The second end of the neck connecting piece is connected with the first end of the first tee pipe joint, the second end of the first tee pipe joint is connected with the first end of the second tee pipe joint through a seamless steel pipe, the second end of the second tee pipe joint is connected with the first end of the first elbow through a welding pipe, and the second end of the first elbow is connected with the first end of the second elbow through a seamless steel pipe. The invention generates pressure waves by the digital valves connected in parallel, and utilizes phase-staggered amplitude cancellation and liner cavity assembly to perform double filtering, thereby reducing the pressure pulsation of the digital valves, and improving the service life and control performance.

Description

Composite attenuation device and its test method for pressure pulsation of digital valve group

technical field

The invention relates to the field of hydraulic transmission control, in particular to a composite attenuation device for pressure pulsation of a digital valve group and a testing method thereof.

Background technique

The contemporary energy crisis and modern industrial development have put forward higher and higher requirements for hydraulic transmission technology in terms of energy saving, reliability, maintainability, low cost and intelligence. With the advantages of energy saving, good fault tolerance, strong interchangeability, high cost performance and strong anti-pollution ability, digital hydraulics closely follows the development theme of the times, and has become the frontier and hotspot of modern fluid transmission technology research. The beginning of intelligence.

Currently, digital hydraulic components with flow discretization characteristics include digital valves, digital pumps, digital cylinders and digital accumulators. The digital valve will cause pressure pulsation during the switching control process. When multiple parallel digital valves work together, the fluids between the various branches are transmitted, converged and coupled under the reciprocating excitation of the switching valves at different frequencies and speeds. Crosstalk will not only affect the force and stability of the digital valve, but also aggravate the pressure pulsation in the main and branch flow, cause vibration and noise, and seriously affect the flow control accuracy of the parallel discrete liquid resistance. Therefore, it is not only necessary to perform pressure pulsation testing on the digital valve group, but also to attenuate the pressure pulsation during the switching control process of the digital valve. The life and performance of the digital valve control system are of great significance.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a composite attenuation device for pressure pulsation of digital valve group and its test method, which utilizes the liner cavity assembly and the phase-staggered amplitude cancellation of pressure waves generated by parallel digital valves Doubly filtered to separate the neck connection from the resonant pressure pulsations generated by the liner chamber liner and the liner chamber shell in the liner chamber assembly with the interference type pressure pulsations generated by the first digital valve and the second digital valve Combined, the pressure pulsation caused by the digital valve during the switch control process is finally reduced, and the life of the digital valve and the performance of the entire control system are improved.

The invention provides a composite attenuation device for pressure pulsation of a digital valve group, which includes a neck connection piece, a lining cavity assembly and an HQ pipe assembly, and the liner cavity assembly passes through the neck connection piece and the HQ pipe Component connection; the liner cavity assembly, which includes a combination gasket, a liner cavity inner liner, a liner cavity shell and a liner cavity top cover, the first mounting end of the neck connector passes through the combination gasket and the liner The first installation end of the cavity shell is connected, the installation end of the liner cavity inner liner is connected with the second installation end of the liner cavity shell, the installation end of the liner cavity top cover is connected to the liner cavity The third installation end of the shell is connected; the HQ pipe assembly includes the first three-way pipe joint, the second three-way pipe joint, the third three-way pipe joint, the first seamless steel pipe, the second seamless steel pipe, the first Three seamless steel pipes, a first welded pipe, a second welded pipe, a first elbow and a second elbow, the second installation end of the neck connector is connected to the first end of the first three-way pipe joint, so The second end of the first three-way pipe joint is connected through the second seamless steel pipe and the first end of the second three-way pipe joint, and the second end of the second three-way pipe joint is connected through the first welded pipe and the first The first end of the elbow is connected, the second end of the first elbow is connected through the third seamless steel pipe and the first end of the second elbow, and the second end of the second elbow is connected through the second welded pipe It is connected with the first end of the third three-way pipe joint, and the second end of the third three-way pipe joint is connected with the third end of the first three-way pipe joint through the first seamless steel pipe; the first The three-way pipe joint, the first seamless steel pipe, the second seamless steel pipe, the second three-way pipe joint and the third three-way pipe joint form a main pipeline, and the transfer matrix of the main pipeline is mathematical The model expression is:

Simplifies to:

Among them, P ₃ is the pulsating pressure at the third section, Q ₃ is the flow rate at the third section, P ₄ is the pulsating pressure at the fourth section, Q ₄ is the flow rate at the fourth section, Γ(s) is equal to The propagation operator of the cross-section pipeline unit, Z ₃ (s) is the characteristic impedance of the basic unit b, Z ₄ (s) is the characteristic impedance of the basic unit e, A ₁₁ , A ₁₂ , A ₂₁ , A ₂₂ are the characteristic impedance of the main pipeline four terminal parameters;

The first welded pipe, the first elbow, the second elbow, the third seamless steel pipe and the second welded pipe form an auxiliary pipeline, and the transfer matrix mathematical model of the auxiliary pipeline The expression is:

Among them, P ₅ is the pulsating pressure at the fifth section, P ₆ is the pulsating pressure at the sixth section, Q ₅ is the flow at the fifth section, Q ₆ is the flow at the sixth section, Γ(s) is equal to The propagation operator of the cross-section pipeline unit, Z ₅ (s) is the characteristic impedance of the basic unit g;

The mathematical model expression of the transfer matrix of the composite attenuation device is:

in,

Among them, Z ₅ (s) is the characteristic impedance of the basic unit g, Γ(s) is the propagation operator of the equal-section pipeline unit, P ₁ is the pulsating pressure at the first section, and Q ₁ is the flow rate at the first section , P ₂ is the pulsating pressure at the second section, Q ₂ is the flow rate at the second section, T ₁₁ , T ₁₂ , T ₂₁ and T ₂₂ are the parameters of the four terminals in the composite damping device, A ₁₁ , A ₁₂ , A ₂₁ and A ₂₂ are the four-terminal parameters of the main pipeline.

Preferably, according to the composition structure of the lining cavity component, an equivalent model of the lining cavity component is established, and the lining cavity component is equivalent to equivalent resistance, equivalent inductance and equivalent capacitance in sequence, and the equivalent resistance , which includes radiation resistance and viscous resistance, the expression of the radiation resistance is:

where R _r is the radiation resistance, c _e is the effective velocity of the lining cavity assembly, k _e is the effective wave number of the lining cavity assembly, ρ is the material density, and _S is the cross-sectional area of the neck connector;

The expression of the viscous resistance is:

R _w ＝2m ₂ ωα _w

Among them, R _w is the viscous resistance, α _w is the loss factor of complex wave number, m ₂ is the equivalent mass of oil in the neck connector, and ω is the angular frequency;

The expression of equivalent resistance is:

Among them, _RJ is the equivalent resistance, _Rr is the radiation resistance, _{Rw is} the viscous resistance, and _S2 is the cross-sectional area of the neck connector;

The equivalent inductance is caused by the oil in the neck connector, and the equivalent mass expression of the oil in the neck connector is:

m ₂ =ρS ₂ L' ₂

Among them, m ₂ is the equivalent mass of oil in the neck connector, ρ is the material density, L ₂ ' is the equivalent length of the neck connector, S ₂ is the cross-sectional area of the neck connector;

The expression for the equivalent inductance is:

Among them, L _J is the equivalent inductance, m ₂ is the equivalent mass of oil in the neck connector, and S ₂ is the cross-sectional area of the neck connector;

The expression for the equivalent capacitance is:

Among them, C _J is the equivalent capacitance, V _L is the volume of the inner lining of the lining cavity, V _f is the volume of hydraulic oil in the structure, β _L ' is the storage modulus of the inner lining of the lining cavity, and β _L ” is the lining The dissipation modulus of the cavity lining, _βf is the bulk modulus of the hydraulic oil.

Preferably, in the HQ pipe assembly, according to the mathematical model of the transfer matrix of the composite attenuation device, the installation position of the third three-way pipe joint is set as the basic unit a, and the installation position of the first seamless steel pipe is set as Basic unit b, the installation position of the first three-way pipe joint is set as basic unit c, the cavity structure of the lining cavity assembly is set as basic unit d, the installation position of the second seamless steel pipe is set as basic unit e, the second three The installation position of the pipe joint is set as the basic unit f, and the installation position of the auxiliary pipeline in the HQ pipe assembly is set as the basic unit g.

Preferably, the mathematical model of the transfer matrix of the basic unit b is:

The transfer matrix mathematical model of the basic unit e is:

The transfer matrix mathematical model of the basic unit g is:

Among them, Z ₃ (s) is the characteristic impedance of the basic unit b, Z ₄ (s) is the characteristic impedance of the basic unit e, Z ₅ (s) is the characteristic impedance of the basic unit g, Γ(s) is the equal-section pipeline The spread operator for the unit.

Preferably, the mathematical models of the transfer matrix of the basic unit c are respectively:

Among them, Z _c is the system impedance of the lined cavity assembly part.

The second aspect of the present invention provides a test method for the composite damping device for pressure pulsation of the aforementioned digital valve group, which includes the following steps:

S1. Connect the output terminal of the variable frequency motor to the control terminal of the hydraulic pump, connect the control terminal of the variable frequency motor to the output terminal of the controller, and connect the overflow valve to the side of the hydraulic pump in parallel, and connect the first digital valve to the second digital valve. The valves are connected in parallel to form a digital valve group, and the input ends of the digital valve group drive board are respectively connected to the control ends of the first digital valve and the second digital valve;

S2. Connect the oil supply port of the hydraulic pump to the first pressure sensor in series and connect it to the first end of the digital valve group, and connect the second end of the digital valve group to the third installation end of the third three-way pipe joint in the composite attenuation device Connecting, connecting the third installation end of the second three-way pipe joint in the composite attenuation device in series with the second pressure sensor and connecting it with the flow sensor, the flow control valve and the oil tank in sequence;

S3. The information collected by the digital valve group driver board, the first pressure sensor, the second pressure sensor and the flow sensor is transmitted to the controller through the collection board.

Preferably, the variable frequency motor, the overflow valve and the hydraulic pump form a hydraulic power circuit; the first digital valve, the second digital valve, the composite attenuation device, the flow control The valve, the first pressure sensor, the second pressure sensor and the flow sensor form a test loop; the controller, the acquisition board and the digital valve group drive board form a control acquisition loop.

Compared with the prior art, the present invention has the following advantages:

1. The present invention uses the liner cavity assembly and the phase-staggered amplitude cancellation of the pressure wave generated by the parallel digital valve to perform double filtering, and combines the resonance-type pressure pulsation with the interference-type pressure pulsation, making it suitable for digital valve groups in The composite attenuation device of low-frequency pressure pulsation reduces the pressure pulsation caused by the digital valve during the switch control process and improves the life of the digital valve.

2. The present invention is conducive to improving the control performance of the digital valve by suppressing vibration and noise, thereby improving the life of the digital valve and the performance of the digital valve control system. At the same time, the pressure pulsation measurement method for the digital valve group can improve the accuracy of the measurement , which is conducive to exploring the relevant mechanism affecting the pressure pulsation of the digital valve group.

Description of drawings

Fig. 1 is the working principle diagram of the composite attenuation device facing the digital valve group pressure pulsation according to the present invention;

Fig. 2 is a structural schematic diagram of a composite attenuation device for digital valve group pressure pulsation according to the present invention;

Fig. 3 is a structural diagram of the neck connector and the lining cavity assembly in the composite attenuation device facing digital valve group pressure pulsation according to the present invention;

Fig. 4 is the structural diagram of the HQ assembly in the complex attenuation device facing digital valve group pressure pulsation according to the present invention;

Fig. 5 is the test schematic diagram of the test method of the compound type attenuation device facing digital valve group pressure pulsation according to the present invention;

Fig. 6 is the insertion loss diagram under different load end pressures and pulsation frequencies of the test method of the composite attenuation device for digital valve group pressure pulsation according to the present invention;

Fig. 7 is a diagram of the insertion loss of the test method of the composite attenuation device facing digital valve group pressure pulsation under different lining cavity lining bulk modulus and pulsation frequency of the present invention;

Fig. 8 is a graph of insertion loss under different neck diameters and pulsation frequencies of the test method of the composite attenuation device for digital valve group pressure pulsation according to the present invention.

Main reference signs:

Neck Connector 1, Liner Chamber Assembly 2, HQ Tube (Herschel-Quincke Tube) Assembly 3, First Tee Fitting 4, Combined Gasket 5, Liner Chamber Liner 6, Liner Chamber Shell 7, Liner Chamber Body top cover 8, first seamless steel pipe 9, second seamless steel pipe 10, second tee pipe joint 11, first welded pipe 12, first elbow 13, second elbow 14, third seamless steel pipe 15. The second welded pipe 16, the third three-way pipe joint 17, the frequency conversion motor 18, the first pressure sensor 19, the first digital valve 20, the second digital valve 21, the digital valve group drive board 22, and the composite attenuation device 23 , a flow sensor 24, a flow control valve 25, a controller 26, an acquisition board 27, a second pressure sensor 28, and an overflow valve 29.

Detailed ways

In order to detail the technical content, structural features, achieved goals and effects of the present invention, the following will be described in detail in conjunction with the accompanying drawings.

Using the liner cavity assembly 2 and the phase-staggered amplitude cancellation of the pressure waves generated by the parallel digital valves to perform double filtering, combining the resonant pressure pulsation and the interference-type pressure pulsation, a composite pressure pulsation oriented digital valve group is proposed. Type attenuation device, as shown in Fig. 1, Fig. 3 and Fig. 4, includes neck connector 1, lining chamber assembly 2 and HQ pipe assembly 3, and liner chamber assembly 2 passes through neck connector 1 and HQ pipe assembly 3 connect.

The lining chamber assembly 2 adopts a split structure, which is convenient for adjustment and installation, and can reduce the price and cost and improve the machining accuracy, as shown in Figure 2, specifically including the combined gasket 5, the inner lining of the lining chamber 6, the lining The cavity shell 7 and the lining cavity top cover 8, the first mounting end of the neck connector 1 are threadedly connected with the first mounting end of the lining cavity shell 7 through the combination gasket 5, and the combination gasket 5 ensures that the No oil leakage, the installation end of the lining chamber lining 6 is adhered to the second installation end of the lining chamber casing 7 by vulcanization, and the installation end of the lining chamber top cover 8 is threaded and the third installation end of the lining chamber casing 7 The installation end is connected, and an ED gasket is installed in the middle to ensure no oil leakage under this connection method.

In the hydraulic system, the oil medium in the neck connector 1 can be regarded as a small liquid column with corresponding mass. When the pulsating pressure acts on the small liquid column, the small liquid column reciprocates like a piston, lining the cavity Component 2 is similar to the mass-spring-damper system, the small liquid column is equivalent to mass, the cavity structure d of the lining cavity component 2 is equivalent to a spring, and the damping and friction of the cavity structure d of the lining cavity component 2 are equivalent to for damping.

Specifically, the composite attenuation device 23 uses the liner cavity assembly 2 and the phase-staggered amplitude cancellation of the pressure waves generated by the parallel digital valves to perform double filtering. According to the composition structure of the liner cavity assembly 2, the liner cavity assembly The equivalent model of 2, the lining cavity component 2 is equivalent to equivalent resistance, equivalent inductance and equivalent capacitance in turn, the equivalent resistance is composed of radiation resistance and viscous resistance, and the expression of radiation resistance is:

where R _r is the radiation resistance, c _e is the effective velocity of the lining cavity assembly 2, ke _is the effective wave number of the lining cavity assembly 2, ρ is the material density, and _S is the cross-sectional area of the neck connector 1.

The expression for viscous resistance is:

R _w ＝2m ₂ ωα _w

Among them, R _w is the viscous resistance, α _w is the loss factor of complex wave number, m ₂ is the equivalent mass of oil in the neck connector 1, and ω is the angular frequency.

It can be obtained that the expression of the equivalent resistance is:

Among them, _RJ is the equivalent resistance, _Rr is the radiation resistance, _Rw is the viscous resistance, and _S2 is the cross-sectional area of the neck connector 1.

The characteristic impedance expression of the inner lining 6 of the lining cavity is:

Wherein, Z _c is the system impedance of the lining cavity assembly 2, R _J is the equivalent resistance, L _J is the equivalent inductance, and ω is the angular frequency.

The equivalent inductance is caused by the oil in the neck connector 1, and the equivalent mass expression of the oil in the neck connector 1 is:

m ₂ =ρS ₂ L' ₂

Among them, m ₂ is the equivalent mass of oil in the neck connector 1, ρ is the material density, L ₂ ′ is the equivalent length of the neck connector 1, and S ₂ is the cross-sectional area of the neck connector 1.

The expression for the equivalent inductance is:

Among them, L _J is the equivalent inductance, m ₂ is the equivalent mass of oil in the neck connector 1, and S ₂ is the cross-sectional area of the neck connector 1.

The equivalent capacitance is caused by the oil in the cavity structure of the lining cavity assembly 2 and the capacitance of the inner lining 6 of the lining cavity, and the expression of the equivalent capacitance is:

Among them, C _J is the equivalent capacitance, V _L is the volume of the lining 6 in the lining cavity, V _f is the volume of the hydraulic oil in the lining 6 of the lining cavity, β _L ' is the energy storage mode of the lining 6 in the lining cavity β _L ” is the dissipation modulus of lining 6 in the lining cavity, and β _f is the bulk modulus of hydraulic oil.

The present invention adopts the transmission loss method to evaluate the pressure pulsation suppression effect, and the transmission loss (Transmission Loss, TL) is the acoustic performance evaluation index of the pressure pulsation composite attenuation device 23 applied to the acoustic muffler. Transmission loss is defined in acoustics as the difference between the incident sound power level at the entrance of the muffler and the sound power level at the exit when there is no reflection at the exit;

In an ideal hydraulic system with a muffler terminal, for a pressure pulsation composite attenuator 23 with a four-terminal parameter transfer matrix mathematical model, the transmission loss expression is calculated and solved by the four-terminal parameter of the transfer matrix mathematical model, and the specific expression is as follows :

Among them, Z ₀ (s) is the characteristic impedance of the medium-section pipeline unit of the HQ tube assembly 3 , and T ₁₁ , T ₁₂ , T ₂₁ and T ₂₂ are the four-terminal parameters in the composite attenuation device 23 respectively.

In a preferred implementation of the present invention, the length _L1 of the liner cavity liner 6 of the liner cavity assembly 2 structural parts will affect the equivalent capacitance, and further affect the attenuation effect of the composite attenuation device 23. Therefore, it is necessary to adjust the liner cavity The effect of the length L1 of the inner lining ₆ on the pressure pulsation attenuation effect is analyzed. Firstly, other parameters except the length _L1 of the inner lining 6 of the inner lining cavity are set as constant values, and the length L of the inner lining 6 of different lining inner chambers is taken respectively. _1. Substituting the length L1 of the lining ₆ of different lining cavities into the above equivalent capacitance expression, and then substituting the mathematical model of the transfer matrix of the composite attenuation device 23 into the above transmission loss expression, thus: the lining cavity The longer the length _L1 of the component 2, the better the attenuation effect and the higher the effective operating frequency range; and the length of the lining cavity component 2 has a moderate effect on the effective operating frequency range and the transmission loss amplitude of the composite attenuation device 23 .

The bulk modulus β _L of the lining cavity lining 6 of the lining cavity assembly 2 structural part will affect the equivalent capacitance, and further affect the attenuation effect of the composite attenuation device 23, so it is necessary to influence the bulk modulus of the lining cavity lining 6 The attenuation effect of pressure pulsation is analyzed, and other parameters except the bulk modulus of the lining cavity are given as constant values _. 6 Substitute the bulk modulus β _L into the equivalent capacitance expression, and then substitute the transfer matrix mathematical model of the composite attenuation device 23 into the above transmission loss expression. Thus it can be obtained that: as the bulk modulus of the lining cavity 6 increases, the effective operating frequency range of the composite attenuator 23 decreases, and at the same time the transmission loss amplitude decreases; and the bulk modulus of the lining cavity 6 is The effective operating frequency range and the transmission loss amplitude of the composite attenuator 23 are significantly affected.

The neck connector 1 will have a greater impact on the pressure pulsation attenuation effect of the digital valve group under low-frequency working conditions due to its inductive and resistive properties.

Since the length L of the neck connector 1 _will affect the equivalent inductance and equivalent resistance, and further affect the attenuation effect of the composite attenuation device 23, it is necessary to analyze the effect of the length of the neck connector 1 on the pressure pulsation attenuation effect. Other parameters except the length of the neck connector 1 are fixed values. Take the length L ₂ of different neck connectors 1 respectively, and substitute the length L ₂ of different neck connectors 1 into the equivalent mass expression of the neck connector 1 above, and then substitute the mathematical model of the transfer matrix of the composite attenuation device 23 into the above The expression of transmission loss can thus be obtained: as the neck length L _increases , the effective operating frequency range of the composite attenuator ₂₃ decreases, and the amplitude of the transmission loss decreases simultaneously; The effective operating frequency range and transmission loss amplitude are moderately affected.

Since the diameter _d2 of the neck connector 1 will affect the equivalent inductance and equivalent resistance, and further affect the attenuation effect of the composite attenuation device 23, it is necessary to analyze the effect of the diameter _d2 of the neck connector 1 on the pressure pulsation attenuation effect, first Given other parameters except the diameter d ₂ of the neck joint 1 as fixed values, different diameters d ₂ of the neck joint 1 are taken respectively. Substituting different neck connector 1 diameters d ₂ into the neck equivalent mass expression above, and then substituting the transfer matrix mathematical model of the composite attenuation device 23 into the above transmission loss expression, it can be obtained: The effective operating frequency range of the composite attenuator 23 increases with the increase of the internal diameter, and at the same time the transmission loss increases, and the neck diameter _d2 has a great influence on the effective operating frequency range of the composite attenuator 23 and the magnitude of the transmission loss.

HQ pipe assembly 3, as shown in Figure 4, comprises the first three-way pipe joint 4, the first seamless steel pipe 9, the second seamless steel pipe 10, the second three-way pipe joint 11, the first welded pipe 12, the first Elbow 13, second elbow 14, third seamless steel pipe 15, second welded pipe 16 and third three-way pipe joint 17, the second installation end of neck connector 1 and the first three-way pipe joint 4 The first end is connected, the second end of the first three-way pipe joint 4 is connected through the first end of the second seamless steel pipe 10 and the second three-way pipe joint 11, and the second end of the second three-way pipe joint 11 is passed through the first end of the second three-way pipe joint 11. A welded pipe 12 is connected with the first end of the first elbow 13, the second end of the first elbow 13 is connected with the first end of the second elbow 14 by the third seamless steel pipe 15, the second elbow 14 The second end is connected by the first end of the second welded pipe 16 and the third three-way pipe joint 17, and the second end of the third three-way pipe joint 17 is connected by the first seamless steel pipe 9 and the first three-way pipe joint 4. Third end connection. The connection mode of the HQ tube assembly 3 can more conveniently adjust the dimensional error occurring in the assembly process, and improve the error tolerance rate of the overall prototype assembly.

Specifically, the mathematical model of the overall transfer matrix of the composite attenuation device 23 is constructed by using the hydroelectric analogy method, and it is divided into basic units. As shown in Figure 2, the installation position of the third three-way pipe joint 17 is set to The basic unit a, the installation position of the first seamless steel pipe 9 is set as the basic unit b, the installation position of the first three-way pipe joint 4 is set as the basic unit c, the cavity structure of the lining cavity assembly 2 is set as the basic unit d, The installation position of the second seamless steel pipe 10 is set as the basic unit e, the basic unit b, the basic unit e and the basic unit g are all equal-section pipeline units, and the installation position of the second three-way pipe joint 11 is set as the basic unit f, The installation position of the auxiliary pipeline in the HQ pipe assembly 3 is set as the basic unit g.

The mathematical model of the transfer matrix of the basic unit b is:

The mathematical model of the transfer matrix of the basic unit e is:

The mathematical model of the transfer matrix of the basic unit g is:

Among them, Z ₃ (s) is the characteristic impedance of the basic unit b, Z ₄ (s) is the characteristic impedance of the basic unit e, Z ₅ (s) is the characteristic impedance of the basic unit g, Γ(s) is the equal-section pipeline The spread operator for the unit.

The mathematical models of the transfer matrix of the basic unit c are:

Wherein, Z _c is the system impedance of the lining cavity assembly 2 .

The HQ pipe assembly 3 is composed of the main pipeline and the auxiliary pipeline in parallel. The pipeline forms two pipelines at the first branch, and merges into one at the second branch; the two pipelines in the HQ pipe assembly 3 The difference in length produces a phase difference, and the two columns of pressure waves "interfere" at the second branch to achieve the effect of attenuating the pressure pulsation. The first three-way pipe joint 4, the first seamless steel pipe 9, the second seamless steel pipe 10, the second three-way pipe joint 11 and the third three-way pipe joint 17 form the main pipeline, and the transfer matrix mathematical model expression of the main pipeline for:

can be simplified to:

Among them, P ₃ is the pulsating pressure at the third section, Q ₃ is the flow rate at the third section, P ₄ is the pulsating pressure at the fourth section, Q ₄ is the flow rate at the fourth section, Γ(s) is equal to The propagation operator of the cross-section pipeline unit, Z ₃ (s) is the characteristic impedance of the basic unit b, and Z ₄ (s) is the characteristic impedance of the basic unit e.

The first welded pipe 12, the first elbow 13, the second elbow 14, the third seamless steel pipe 15 and the second welded pipe 16 form an auxiliary pipeline, and the mathematical model expression of the transfer matrix of the auxiliary pipeline is:

Among them, P ₅ is the pulsating pressure at the fifth section, P ₆ is the pulsating pressure at the sixth section, Q ₅ is the flow at the fifth section, Q ₆ is the flow at the sixth section, Γ(s) is equal to The propagation operator of the section pipeline unit, Z ₅ (s) is the characteristic impedance of the basic unit g.

The transfer matrix mathematical model expression of composite attenuation device 23 is:

in,

Among them, Z ₅ (s) is the characteristic impedance of the basic unit g, Γ(s) is the propagation operator of the equal-section pipeline unit, P ₁ is the pulsating pressure at the first section, and Q ₁ is the flow rate at the first section , P ₂ is the pulsating pressure at the second section, Q ₂ is the flow rate at the second section, T ₁₁ , T ₁₂ , T ₂₁ and T ₂₂ are the parameters of the four terminals in the composite attenuation device.

Specifically, the speed and displacement of the hydraulic pump are changed by the frequency conversion motor 18, and the overflow valve 29 is mainly used for pressure limiting, and is used as a safety valve to protect the safe operation of the hydraulic system. At the same time, the overflow valve 29 adjusts the digital valve group at the hydraulic pump port Before the previous pressure, the hydraulic pump provides oil with constant pressure for the entire hydraulic system. The oil inlet of the hydraulic pump draws the fluid medium from the oil tank to provide the hydraulic system with a certain flow and pressure of the fluid medium. The fluid medium generates pressure through the digital valve group. Pulsation, the digital valve group will produce different pressure pulsations for different PWM signal inputs. The composite attenuation device 23 is connected to the hydraulic system through a steel straight pipe, and the fluid medium flows through the composite attenuation device 23 and passes through the pressure sensor and flow sensor 24. , flows back to the oil tank through the flow control valve 25, the flow control valve 25 adopts a manual control throttle valve, which can adjust the pressure at the load end, thereby simulating the change of the load end pressure of the composite attenuation device 23 prototype, the controller and the acquisition board 27 pass The CAN bus is connected to realize real-time data transmission, and the two cooperate to realize the functions of controlling the digital valve group driving board 22 and collecting the data of the second pressure sensor 28 and the flow sensor 24 .

Frequency conversion motor 18, overflow valve 29 and hydraulic pump form a hydraulic power circuit. The hydraulic pump is connected to the upper machine position through CAN bus to monitor the state of the mobile oil source and change the maximum output pressure and maximum output of the mobile oil source in real time. flow rate and other parameters; the first digital valve 20, the second digital valve 21, the composite attenuation device 23, the flow control valve 25, the first pressure sensor 19, the second pressure sensor 28 and the flow sensor 24 are composed, and the test circuit ensures that The rationality of the experiment ensures the accuracy of the pressure pulsation measurement to the greatest extent; the controller, the acquisition board 27 and the digital valve group drive board 22 form a control acquisition circuit, and the electronic control part of the control acquisition circuit is mainly responsible for the digital valve group The electric signal input of the driving board 22 and the data collection of the pressure and flow sensor 24.

A composite attenuation device and testing method for digital valve group pressure pulsation of the present invention will be further described in conjunction with the following examples:

According to the structural characteristics of the liner cavity assembly 2 in the composite attenuation device 23, in this specific embodiment, the outer diameter _D1 of the liner cavity shell 7 is set to 59mm, and the main pipeline diameter _dp is set to 10mm, while ensuring Under the premise of the requirements of the structural pressure rating (preliminary calculation of the wall thickness of the structure according to the experience in engineering design), the maximum volume of the cavity structure in the lining cavity assembly 2 is about 0.4L.

At the same time, in order to be suitable for the pressure pulsation of the digital valve group in low-frequency working conditions, the bulk modulus of the lining cavity assembly 2 β _L ≤ 20MPa; The size of the installation space is limited, the length of the neck connector 1 is controlled at 50mm≤L ₂ ≤60mm, the diameter of the neck connector 1 is controlled at d ₂ ≤10mm, specifically, the shorter the length _L2 of the neck connector 1 , the larger the diameter d ₂ of the neck connector 1 is, the higher the operating frequency range of the structural part of the lining cavity assembly 2 is. However, with the increase of the length L ₂ of the neck connector 1 and the decrease of the diameter d ₂ of the neck connector 1, the overall operating frequency is more suitable for the pressure pulsation of the low-frequency working condition of the digital valve group, but the pressure pulsation attenuation effect is worse , Therefore, under the premise of combining with the actual situation of the project, the length L ₂ of the neck connector 1 is selected as 50mm, and the diameters d ₂ of three neck connectors 1 are designed to be 6mm, 8mm and 10mm respectively.

选用20Hz、50Hz和80Hz三种数字阀组工作过程中的典型压力脉动频率进行分析，得出不同HQ管直径及长度下的传递损失，在20Hz、50Hz和80Hz三种数字阀组工作过程中的典型压力脉动频率下，均在HQ管的长度及直径上限处，传递损失达到最大值，HQ管长度l₅与HQ管直径d₅的增加会提高复合型衰减装置23的衰减效果，在本实施例中，根据HQ管组件3外形尺寸及主管路的接头接口尺寸限制，HQ管组件3长度l₅≤900mm，HQ管组件3直径d₅≤20mm，选用HQ管组件3长度l₅＝900mm，HQ管组件3直径d₅＝20mm为最佳。且低频段的工作特性表现更为优越，在本申请实施例中，最终选择HQ管组件3长度l₅＝900mm，HQ管直径d₅＝20mm。Since the structural parameters of the HQ pipe assembly 3 have an obvious influence on the attenuation effect of the pressure pulsation, the boundary conditions of the diameter _d5 and the length _l5 of the HQ pipe assembly 3 (whether it is a seamless steel pipe or a welded pipe, corresponding to each other) are set as:

The typical pressure pulsation frequency in the working process of three digital valve groups of 20Hz, 50Hz and 80Hz is selected for analysis, and the transmission loss under different HQ tube diameters and lengths is obtained. Under the typical pressure pulsation frequency, the transmission loss reaches the maximum value at the upper limit of the length and diameter of the HQ tube, and the increase of the HQ tube length l ₅ and the HQ tube diameter d ₅ will improve the attenuation effect of the composite attenuation device 23. In this implementation In the example, according to the external dimensions of the HQ pipe assembly 3 and the size limitation of the joint interface of the main pipeline, the length of the HQ pipe assembly 3 is l ₅ ≤ 900mm, the diameter of the HQ pipe assembly 3 is d ₅ ≤ 20mm, and the length of the HQ pipe assembly 3 is l ₅ = 900mm, The diameter d ₅ =20mm of the HQ pipe assembly 3 is optimal. Moreover, the working characteristics in the low frequency band are more superior. In the embodiment of the present application, the length l ₅ of the HQ tube assembly 3 is finally selected to be 900 mm, and the diameter of the HQ tube d ₅ =20 mm.

In this implementation, the test method for the composite attenuation device for the pressure pulsation of the digital valve group, as shown in Figure 5, includes the following steps:

S1. Connect the output terminal of the variable frequency motor 18 to the control terminal of the hydraulic pump, connect the control terminal of the variable frequency motor 18 to the output terminal of the controller, and connect the overflow valve 29 to one side of the hydraulic pump in parallel, and connect the first digital valve 20 It is connected in parallel with the second digital valve 21 to form a digital valve group. The digital valve group is the source of pressure pulsation. For different PWM signal inputs, different pressure pulsations will be produced, and then the pressure pulsation will be transmitted to the composite attenuation device 23. The digital valve passes through the cover plate Installed on the valve body of the digital valve group, the upper part is driven by the electromagnetic coil, and the input end of the digital valve group driving board 22 is connected with the control ends of the first digital valve 20 and the second digital valve 21 respectively.

S2. Connect the oil supply port of the hydraulic pump to the first pressure sensor 19 in series and connect it to the first end of the digital valve group, and connect the second end of the digital valve group to the first end of the third three-way pipe joint 17 in the composite damping device 23 The three installation ends are connected, and the third installation end of the second three-way pipe joint 11 in the composite attenuation device 23 is connected in series with the second pressure sensor 28 and connected with the flow sensor 24, the flow control valve 25 and the fuel tank in sequence, and the composite The type attenuation device 23 is fixed on the bottom plate to ensure that it is in a fixed state during the test; the second pressure sensor 28 is a current type pressure sensor, which is used to test the pressure response curve of the composite type attenuation device 23 under different working conditions , and collect data into the built-in board of the controller. The flow sensor 24 is a voltage sensor, which is collected through the collection board 10 and transmitted to the controller through CAN communication, mainly to test the flow value of the oil return circuit of the hydraulic system , corresponding to the flow input at the load end during the working process of the digital valve group, the flow control valve 25 mainly plays the role of simulating the load of the hydraulic system, and controls the pressure at the load end by controlling the valve opening of the flow control valve 25 .

S3. The information collected by the digital valve group driver board 22, the first pressure sensor 19, the second pressure sensor 28 and the flow sensor 24 is transmitted to the controller through the acquisition board 27, and the controller transmits the collected data to the upper position through the CAN bus In the machine program, to adjust the pressure of the entire hydraulic system.

In this test method, the hydraulic pump provides a fluid medium with a certain flow rate and pressure. The fluid medium passes through the digital valve group to generate pressure pulsation, and then flows through the composite attenuation device 23, passes through the pressure sensor and flow sensor 24, and flows through the flow control valve 25. The oil return tank, the controller and the acquisition board 27 are connected through the CAN bus to realize real-time data transmission. At the same time, the two cooperate to realize the control of the digital valve group drive board 22 and the collection of pressure sensor and flow sensor data, and measure different load end pressures (3MPa , 4MPa, 5MPa) and pulsation frequency insertion loss diagram, as shown in Figure 6, different lining cavity lining bulk modulus (10MPa, 15MPa, 20MPa) and the insertion loss diagram under pulsation frequency, as shown in Figure 7 , the insertion loss diagram under different neck diameters (4mm, 6mm, 8mm) and pulsation frequency, as shown in Figure 8.

The above-mentioned embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. All such modifications and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (6)

1. A composite attenuation device facing digital valve group pressure pulsation, which includes a neck connector, a lining chamber assembly and an HQ pipe assembly, and the lining chamber assembly is connected to the HQ pipe assembly through a neck connector , characterized in that, The liner cavity assembly includes a combined gasket, a liner cavity inner liner, a liner cavity shell and a liner cavity top cover, the first mounting end of the neck connector passes through the combination gasket and the liner cavity shell The first installation end of the lining chamber is connected, the installation end of the lining cavity is connected with the second installation end of the lining cavity shell, the installation end of the lining cavity top cover is connected with the second installation end of the lining cavity shell Three installation end connections; The HQ pipe assembly includes a first three-way pipe joint, a second three-way pipe joint, a third three-way pipe joint, a first seamless steel pipe, a second seamless steel pipe, a third seamless steel pipe, a first welding pipe, a second welded pipe, a first elbow and a second elbow, the second installation end of the neck connector is connected to the first end of the first three-way pipe joint, and the first three-way pipe joint The second end is connected to the first end of the second three-way pipe joint through the second seamless steel pipe, and the second end of the second three-way pipe joint is connected to the first end of the first elbow through the first welded pipe, The second end of the first elbow is connected to the first end of the second elbow through the third seamless steel pipe, and the second end of the second elbow is connected through the second welded pipe and the third three-way pipe joint. The first end is connected, the second end of the third three-way pipe joint is connected through the first seamless steel pipe and the third end of the first three-way pipe joint; In the HQ pipe assembly, according to the mathematical model of the transfer matrix of the composite attenuation device, the installation position of the third three-way pipe joint is set as the basic unit a, the installation position of the first seamless steel pipe is set as the basic unit b, and the installation position of the first seamless steel pipe is set as the basic unit b. The installation position of the first three-way pipe joint is set as the basic unit c, the cavity structure of the lining chamber assembly is set as the basic unit d, the installation position of the second seamless steel pipe is set as the basic unit e, and the installation position of the second three-way pipe joint The position is set as the basic unit f, and the installation position of the auxiliary pipeline in the HQ pipe assembly is set as the basic unit g; The first three-way pipe joint, the first seamless steel pipe, the second seamless steel pipe, the second three-way pipe joint and the third three-way pipe joint form a main pipe, and the main pipe The mathematical model expression of the transfer matrix is:

Simplifies to:

Among them, P ₃ is the pulsating pressure at the third section, Q ₃ is the flow rate at the third section, P ₄ is the pulsating pressure at the fourth section, Q ₄ is the flow rate at the fourth section, Γ(s) is equal to The propagation operator of the cross-section pipeline unit, Z ₃ (s) is the characteristic impedance of the basic unit b, Z ₄ (s) is the characteristic impedance of the basic unit e, A ₁₁ , A ₁₂ , A ₂₁ , A ₂₂ are the characteristic impedance of the main pipeline Four-terminal parameters, _Zc is the system impedance of the lining cavity assembly part; The first welded pipe, the first elbow, the second elbow, the third seamless steel pipe and the second welded pipe form an auxiliary pipeline, and the transfer matrix mathematical model of the auxiliary pipeline The expression is:

Among them, P ₅ is the pulsating pressure at the fifth section, P ₆ is the pulsating pressure at the sixth section, Q ₅ is the flow at the fifth section, Q ₆ is the flow at the sixth section, Γ(s) is equal to The propagation operator of the cross-section pipeline unit, Z ₅ (s) is the characteristic impedance of the basic unit g; The mathematical model expression of the transfer matrix of the composite attenuation device is:

in,

Among them, Z ₅ (s) is the characteristic impedance of the basic unit g, Γ(s) is the propagation operator of the equal-section pipeline unit, P ₁ is the pulsating pressure at the first section, and Q ₁ is the flow rate at the first section , P ₂ is the pulsating pressure at the second section, Q ₂ is the flow rate at the second section, T ₁₁ , T ₁₂ , T ₂₁ and T ₂₂ are the four-terminal parameters in the composite damping device, A ₁₁ , A ₁₂ , A ₂₁ , A ₂₂ are the four-terminal parameters of the main pipeline. 2. The composite attenuation device facing digital valve group pressure pulsation according to claim 1, characterized in that, according to the composition structure of the lining chamber assembly, an equivalent model of the lining chamber assembly is established, and the lining chamber assembly is sequentially Equivalent to equivalent resistance, equivalent inductance and equivalent capacitance, the equivalent resistance includes radiation resistance and viscous resistance, and the expression of the radiation resistance is:

where R _r is the radiation resistance, c _e is the effective velocity of the lining in the lining cavity, k _e is the effective wave number of the lining in the lining cavity, ρ is the material density, and _S is the cross-sectional area of the neck connector; The expression of the viscous resistance is: R _w ＝2m ₂ ωα _w Among them, R _w is the viscous resistance, α _w is the loss factor of complex wave number, m ₂ is the equivalent mass of oil in the neck connector, and ω is the angular frequency; The expression of equivalent resistance is:

Among them, _RJ is the equivalent resistance, _Rr is the radiation resistance, _Rw is the viscous resistance, and _S2 is the cross-sectional area of the neck connector; The equivalent inductance is caused by the oil in the neck connector, and the equivalent mass expression of the oil in the neck connector is: m ₂ =ρS ₂ L' ₂ Among them, m ₂ is the equivalent mass of oil in the neck connector, ρ is the material density, L ₂ ' is the equivalent length of the neck connector, S ₂ is the cross-sectional area of the neck connector; The expression for the equivalent inductance is:

Among them, L _J is the equivalent inductance, m ₂ is the equivalent mass of oil in the neck connector, and S ₂ is the cross-sectional area of the neck connector. 3. The composite attenuation device facing digital valve group pressure pulsation according to claim 1, characterized in that, the transfer matrix mathematical model of the basic unit b is:

The transfer matrix mathematical model of the basic unit e is:

The transfer matrix mathematical model of the basic unit g is:

Among them, Z ₃ (s) is the characteristic impedance of the basic unit b, Z ₄ (s) is the characteristic impedance of the basic unit e, Z ₅ (s) is the characteristic impedance of the basic unit g, Γ(s) is the equal-section pipeline The spread operator for the unit. 4. The composite attenuation device facing digital valve group pressure pulsation according to claim 1, characterized in that, the transfer matrix mathematical model of the basic unit c is:

Among them, Z _c is the system impedance of the lined cavity assembly part. 5. A method for testing a composite attenuation device facing digital valve group pressure pulsation according to any one of claims 1-4, characterized in that it comprises the following steps: S1. Connect the output terminal of the variable frequency motor to the control terminal of the hydraulic pump, connect the control terminal of the variable frequency motor to the output terminal of the controller, and connect the overflow valve to the side of the hydraulic pump in parallel, and connect the first digital valve to the second digital valve. The valves are connected in parallel to form a digital valve group, and the input ends of the digital valve group drive board are respectively connected to the control ends of the first digital valve and the second digital valve; S2. Connect the oil supply port of the hydraulic pump to the first pressure sensor in series and connect it to the first end of the digital valve group, and connect the second end of the digital valve group to the third installation end of the third three-way pipe joint in the composite attenuation device Connecting, connecting the third installation end of the second three-way pipe joint in the composite attenuation device in series with the second pressure sensor and connecting it with the flow sensor, the flow control valve and the oil tank in sequence; S3. The information collected by the digital valve group driver board, the first pressure sensor, the second pressure sensor and the flow sensor is transmitted to the controller through the collection board. 6. The test method according to claim 5, characterized in that, the variable frequency motor, the overflow valve and the hydraulic pump form a hydraulic power circuit; the first digital valve, the second digital valve, The composite attenuation device, the flow control valve, the first pressure sensor, the second pressure sensor and the flow sensor form a test loop; the controller, the acquisition board and the digital The valve group drive board forms the control acquisition loop.

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