A piezoelectric stack driven resonant diaphragm pump and method of operation thereof

Abstract

The application discloses a piezoelectric stack driven resonant diaphragm pump and a working method thereof, and relates to the field of intelligent hydraulic pumps. The volume of a pump cavity is greatly changed through the forced vibration principle of a resonator under a basic simple harmonic excitation, so that the oil suction and discharge capacity of the hydraulic pump is enhanced, and the output flow of the hydraulic pump is improved. The resonant diaphragm pump comprises a piezoelectric stack material electric-motor converter, a pump cavity fixedly connected with the piezoelectric stack material electric-motor converter through a support and a resonator arranged between the piezoelectric stack material electric-motor converter and the pump cavity. The application utilizes the resonance principle to improve the output performance of the piezoelectric stack, realizes the improvement of the output flow of the hydraulic pump and improves the efficiency of the hydraulic pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of intelligent hydraulic pump, in particular to a piezoelectric stack driven resonant diaphragm pump. BACKGROUND

[0002] Due to the advantages of small size, high precision and not easy to be interfered by electromagnetic wave, piezoelectric pump has a wide application prospect in the field of medicine, aerospace and micro-mechanical. The piezoelectric stack material driven hydraulic pump uses piezoelectric ceramic to drive, through the high frequency periodic extension and shortening movement of piezoelectric stack material, the volume of pump cavity is changed, so that the pressure in the pump cavity is changed, thereby achieving the purpose of pumping and discharging oil. However, the output displacement of piezoelectric stack material is very limited, the displacement of direct drive is in micrometer level, the volume change brought to the pump cavity is small, which limits the flow output of piezoelectric pump.

[0003] At present, the output flow of piezoelectric stack material driven hydraulic pump has a great gap compared with the actual application. In order to improve the output flow of piezoelectric stack material driven hydraulic pump, usually from the aspects of improving the output displacement of piezoelectric stack material and increasing the number of piezoelectric stack material. Therefore, how to improve the output flow of piezoelectric stack material driven hydraulic pump has become a technical problem to be solved by the person skilled in the art. SUMMARY

[0004] The present application aims at the above problems, and provides a piezoelectric stack driven resonant diaphragm pump and a working method thereof. The forced vibration principle of the resonant body under the basic harmonic excitation is used to greatly change the volume change of the pump cavity, so as to enhance the oil pumping and discharging capacity of the hydraulic pump and improve the output flow of the hydraulic pump.

[0005] The technical scheme of the present application is as follows: the resonant diaphragm pump comprises a piezoelectric stack material electric-mechanical converter I, a pump cavity IV fixedly connected with the piezoelectric stack material electric-mechanical converter I through a support III, and a resonant body II arranged between the piezoelectric stack material electric-mechanical converter I and the pump cavity IV.

[0006] The output end of the piezoelectric stack material electric-mechanical converter I is an output joint 7 capable of reciprocating motion, and the resonant body II is fixedly connected to an output rod 5.

[0007] The resonance body II includes a rectangular spring sheet 19 installed on the output connector 7, a gasket 18 and a mass block 10 installed on the rectangular spring sheet 19 in sequence through a locking screw 17, a positioning output head 15 and a diaphragm top rod 14 installed on the mass block 10 in sequence through a fastening screw 16, and the mass block 10 is spaced apart from the output connector 7 through the gasket 18; the mass block 10 is suspended under the action of the rectangular spring sheet 19, forming a spring-mass system, so that the reciprocating movement of the output connector 7 will reach the mass block 10 after being transmitted through the rectangular spring sheet 19, and finally drive the diaphragm top rod 14 to reciprocate.

[0008] The pump cavity IV includes an annular pump base 12, a diaphragm 13 installed in the pump base 12, a pump cavity height plate 22 and a shunt one-way plate 24 installed on the upper end of the pump base 12 in sequence, and a kapton film 27 installed between the pump cavity height plate 22 and the shunt one-way plate 24.

[0009] The center of the diaphragm 13 is fixedly connected with the top end of the diaphragm top rod 14; so that the reciprocating movement of the diaphragm top rod 14 can directly drive the center of the diaphragm 13 to rise and fall.

[0010] The edges of the diaphragm 13 and the edges of the kapton film 27 are respectively sealed with the bottom surface and the top surface of the pump cavity height plate 22, and one-way flow distribution is performed through the kapton film 27, the edges of the kapton film 27 are also sealed with the bottom surface of the shunt one-way plate 24, and the shunt one-way plate 24 is provided with a one-way oil suction port 26 and a one-way oil discharge port 25 above the kapton film 27, so that under the action of one-way flow distribution of the kapton film 27, oil will be sucked from the one-way oil suction port 26 and pass through the shunt one-way plate 24, the kapton film 27 and the pump cavity height plate 22 to enter the pump cavity generated after deformation of the diaphragm 13, and finally be discharged outward through the one-way oil discharge port 25.

[0011] Further, the shunt one-way plate 24 is provided with an inlet small hole 241 and an outlet large hole 242, and the pump cavity height plate 22 is provided with an inlet large hole 221 and an outlet small hole 222, the one-way oil suction port 26, the inlet small hole 241 and the inlet large hole 221 are sequentially communicated from top to bottom, and the outlet small hole 222, the outlet large hole 242 and the one-way oil discharge port 25 are sequentially communicated from bottom to top, one-way flow distribution is realized by slitting the kapton film 27 between the pump cavity height plate 22 and the shunt one-way plate 24, the slitting position of the kapton film 27 is at the edge of the inlet large hole 221 and the edge of the outlet large hole 242, so that the inlet small hole 241 is one-way conducted to the inlet large hole 221, and the outlet small hole 222 is one-way conducted to the outlet large hole 242.

[0012] Further, the output joint 7 is fixedly connected to the output rod 5 by an output joint fixing screw 8, and a gap is left between the output joint fixing screw 8 and the mass 10.

[0013] Further, the diaphragm is made of beryllium bronze, PDMS film, Kapton flexible film or PET plastic film.

[0014] Further, the diaphragm top rod 14 is bonded to the diaphragm 13 by epoxy resin, the pump base 12 is bonded to the diaphragm 13 by epoxy resin to ensure sealing, and the pump cavity height plate 22, the shunt one-way plate 24 and the kapton film 27 are bonded by epoxy resin to ensure sealing.

[0015] Further, the diaphragm top rod 14 is gap-fitted with the position-adjusting output head 15, and the vertical height of the diaphragm 14 can be adjusted by tightening the clamp.

[0016] Further, the piezoelectric stack material electric-mechanical transducer I comprises a base 1, a shell 4 mounted on the base 1, a bushing 2 mounted in the shell 4, a piezoelectric stack material 3 mounted in the bushing 2, an output rod 5 mounted on the upper end of the piezoelectric stack material 3, an output joint 7 mounted on the upper end of the output rod 5, and a disc spring 6 for providing a restoring force to the output rod.

[0017] The top of the shell 4 is further fixedly connected with a pre-tightening end cover 21, the output rod 5 penetrates through the pre-tightening end cover 21, and the disc spring 6 is sleeved on the output rod 5 and abuts between the stepped surface of the output rod 5 and the bottom surface of the pre-tightening end cover 21. In this way, during the process of energizing and de-energizing the piezoelectric stack material 3, the disc spring is matched to make the output rod 5 and the output joint 7 produce synchronous up-down reciprocating motion.

[0018] Further, the bracket III comprises a plurality of studs 11, the bottom ends of the studs 11 are threadedly connected to the top surface of the shell 4 and locked by a rotation-stopping nut 20, the middle parts of the studs 11 penetrate through the mass 10 and keep separated therefrom, and the top ends of the studs 11 are fixedly connected with the pump base 12.

[0019] The method for using the piezoelectric stack driven resonant diaphragm pump is as follows:

[0020] Step 1, calculate the resonance frequency f of the mechanical system composed of the resonator, and the calculation formula is:

[0021] Wherein, K1 is the stiffness of the rectangular spring sheet, m 质量块 is the mass of the mass in the resonator.

[0022] The calculation formula of the stiffness of the rectangular spring sheet is:

[0023] The calculation formula of the stiffness of the rectangular spring sheet is: where b is the width of the spring leaf; E is the modulus of elasticity of the spring leaf material; h is the thickness; and l is the length of the spring leaf.

[0024] Step 2, set the frequency of the driving signal driving the piezoelectric stack material to the calculated resonance frequency f;

[0025] Step 3, the piezoelectric stack material makes periodic elongation and shortening movement at the resonance frequency, drives the resonator to resonate, and makes the diaphragm move up and down at the resonance frequency f, thereby changing the volume inside the pump cavity; with the periodic change of the pump cavity volume, the oil pumping is completed.

[0026] Compared with the prior art, the advantages of the present application are: the resonance principle is used to improve the output performance of the piezoelectric stack, the output flow of the hydraulic pump is improved, and the efficiency of the hydraulic pump is improved; the piezoelectric stack material electric-mechanical converter is used as the excitation element, so that the resonator and the diaphragm resonate, the resonance of the piezoelectric material is isolated, and the service life of the piezoelectric material is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of the resonant diaphragm pump driven by the piezoelectric stack in the present application;

[0028] Figure 2 It is a front view of the resonant diaphragm pump driven by the piezoelectric stack in the present application;

[0029] Figure 3 It is an explosion schematic diagram of the pump cavity in the present application;

[0030] Figure 4 It is a schematic diagram of the rectangular spring leaf in the present application;

[0031] Figure 5 It is an axial sectional view of the pump cavity in the present application;

[0032] In the figure, I is the piezoelectric stack material electric-mechanical converter, II is the resonator, III is the bracket, and IV is the pump cavity.

[0033] 1 is the base, 2 is the bushing, 3 is the piezoelectric stack material, 4 is the outer shell, 5 is the output rod, 6 is the disc spring, 7 is the output connector, 8 is the output connector fixing screw, 9 is the fixing screw, 10 is the mass block, 11 is the stud, 12 is the pump base, 13 is the diaphragm, 14 is the diaphragm top rod, 15 is the position adjusting output head, 16 is the fastening screw, 17 is the locking screw, 18 is the gasket, 19 is the rectangular spring leaf, 20 is the rotation-stopping nut, 21 is the pre-tightening end cover, 22 is the pump cavity height plate, 221 is the large inlet hole, 222 is the small outlet hole, 24 is the flow dividing one-way plate, 241 is the small inlet hole, 242 is the large outlet hole, 25 is the one-way oil outlet, 26 is the one-way oil inlet, and 27 is the kapton film. DETAILED DESCRIPTION

[0034] In order to clearly illustrate the technical solutions of the present patent, the present patent will be described in detail below with reference to the specific embodiments and drawings thereof.

[0035] The present patent greatly changes the pump cavity volume change through resonance, thereby enhancing the oil suction and discharge capacity of the hydraulic pump and improving the output flow of the hydraulic pump.

[0036] In order to achieve the above-mentioned purpose, the embodiments of the present patent adopt the following technical solutions:

[0037] The resonant diaphragm pump comprises a piezoelectric stack material electric-mechanical converter I, a resonance body II, a bracket III, and a pump cavity IV; the piezoelectric stack material electric-mechanical converter I is installed below the resonance body II; the bracket III is installed on the piezoelectric stack material electric-mechanical converter I and is fastened by screw rod and nut; and the pump cavity IV is installed on the bracket III.

[0038] The piezoelectric stack material electric-mechanical converter I comprises a base 1, an outer shell 4 and piezoelectric stack material 3 installed on the base 1, a bushing 2 installed in the outer shell 4, an output rod 5 installed on the upper end of the piezoelectric stack material 3, a disc spring 6 installed on the upper end of the output rod 5, an output connector 7 installed on the upper end of the output rod 5, and a pre-tightening end cover 21 installed on the disc spring 6.

[0039] Further, the piezoelectric stack material performs high-frequency periodic elongation and shortening movement, and transmits the movement to the resonance body through the output rod.

[0040] The resonance body II comprises a rectangular spring sheet 19 installed on the upper end of the output connector 7 through a fixing screw 9, a gasket 18 and a mass block 10 installed on the rectangular spring sheet 19, a position-adjusting output head 15 and a diaphragm top rod 14 installed on the mass block 10.

[0041] The bracket III is fixed on the outer shell 4 of the piezoelectric stack material electric-mechanical converter I through screw studs and nuts, and the pump cavity IV is installed on the bracket III through two nuts.

[0042] The resonance body drives the diaphragm on the transmission rod to vibrate up and down, so that the volume change occurs in the pump cavity.

[0043] The pump cavity IV comprises a pump base 12 installed on the bracket III, a diaphragm 13 installed on the pump base 12, a pump cavity height plate 22 installed on the upper end of the diaphragm 13, and a kapton film 27 installed between the pump cavity height plate 22 and a shunt one-way plate 24.

[0044] The kapton film 27 needs to be slit along the two long edges of the rectangular large hole after being installed between the pump cavity height plate 22 and the shunt one-way plate 24, so as to provide flow passage and form an integrated one-way valve plate. Specifically, the shunt one-way plate 24 is provided with an inlet small hole 241 and an outlet large hole 242, and the pump cavity height plate 22 is provided with an inlet large hole 221 and an outlet small hole 222, the one-way oil suction hole 26, the inlet small hole 241 and the inlet large hole 221 are sequentially communicated from top to bottom, and the outlet small hole 222, the outlet large hole 242 and the one-way oil discharge hole 25 are sequentially communicated from bottom to top, and the one-way flow distribution is realized by slitting the kapton film 27 between the pump cavity height plate 22 and the shunt one-way plate 24, and the slitting position of the kapton film 27 is at the edge of the inlet large hole 221 and the edge of the outlet large hole 242, so that the inlet small hole 241 is unidirectionally communicated to the inlet large hole 221, and the outlet small hole 222 is unidirectionally communicated to the outlet large hole 242.

[0045] The oil discharge valve plate and the oil suction valve plate unidirectionally distribute oil, the oil discharge valve plate is opened when the pressure in the pump cavity body is increased, and the oil suction valve plate is opened when the pressure in the pump cavity body is reduced.

[0046] The material of the diaphragm includes beryllium bronze, PDMS film, kapton flexible film and PET plastic film.

[0047] The application also discloses a working method of the resonant hydraulic pump driven by the piezoelectric stack material.

[0048] Step 1, the resonance frequency f of the mechanical system composed of the resonator is calculated, and the calculation formula is as follows:

[0049] Wherein, K1 is the stiffness of the rectangular spring sheet, m 质量块 is the mass of the mass block in the resonator.

[0050] The calculation formula of the stiffness of the rectangular spring sheet is as follows:

[0051] Wherein b is the width of the spring sheet, E is the elastic modulus of the spring sheet material, h is the thickness, and l is the length of the spring sheet.

[0052] Step 2, the frequency of the driving signal of the driving piezoelectric stack material is set to the calculated resonance frequency f;

[0053] Step 3, the piezoelectric stack material performs periodic elongation and shortening movement at the resonance frequency, drives the resonator to resonate, and drives the diaphragm to move up and down at the resonance frequency f, so as to change the volume of the pump cavity; with the periodic change of the pump cavity volume, the oil pumping is completed.

[0054] The present application has many specific implementation approaches, and the above description is only the preferred embodiment of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, several improvements can be made, and these improvements should also be considered as the protection scope of the present application.

Claims

1. A piezoelectric stack driven resonant diaphragm pump, characterized by, The resonant diaphragm pump comprises a piezoelectric stack material electromechanical converter (I), a pump cavity (IV) fixedly connected with the piezoelectric stack material electromechanical converter (I) through a support (III), and a resonator (II) arranged between the piezoelectric stack material electromechanical converter (I) and the pump cavity (IV); The output end of the piezoelectric stack material electromechanical converter (I) is an output joint (7) capable of reciprocating motion, and the resonator (II) is fixedly connected to an output rod (5). The resonator (II) comprises a rectangular spring sheet (19) mounted on the output joint (7), a gasket (18) and a mass block (10) mounted on the rectangular spring sheet (19) in sequence, a position adjusting output head (15) and a diaphragm top rod (14) mounted on the mass block (10) in sequence, and a gap is left between the mass block (10) and the output joint (7) through the gasket (18). The pump cavity (IV) comprises an annular pump base (12), a diaphragm (13) mounted in the pump base (12), a pump cavity height plate (22) and a shunt one-way plate (24) mounted on the upper end of the pump base (12) in sequence, and a kapton film (27) mounted between the pump cavity height plate (22) and the shunt one-way plate (24). The center of the diaphragm (13) is fixedly connected to the top end of the diaphragm top rod (14). The edges of the diaphragm (13) and the edges of the kapton film (27) are respectively sealed with the bottom surface and the top surface of the pump cavity height plate (22), one-way flow distribution is performed through the kapton film (27), the edges of the kapton film (27) are also sealed with the bottom surface of the shunt one-way plate (24), and a one-way oil suction port (26) and a one-way oil discharge port (25) are arranged above the kapton film (27) on the shunt one-way plate (24). An inflow small hole (241) and an outflow large hole (242) are arranged in the shunt one-way plate (24), and an inflow large hole (221) and an outflow small hole (222) are arranged in the pump cavity height plate (22), the one-way oil suction port (26), the inflow small hole (241) and the inflow large hole (221) are sequentially communicated from top to bottom, and the outflow small hole (222), the outflow large hole (242) and the one-way oil discharge port (25) are sequentially communicated from bottom to top, one-way flow distribution is realized through the slitting mode of the kapton film (27) between the pump cavity height plate (22) and the shunt one-way plate (24), the slitting position of the kapton film (27) is at the edges of the inflow large hole (221) and the outflow large hole (242), so that the inflow small hole (241) is one-way conducted to the inflow large hole (221), and the outflow small hole (222) is one-way conducted to the outflow large hole (242).

2. A piezoelectric stack driven resonant diaphragm pump according to claim 1, characterized in that, The output joint (7) is fixedly connected to the output rod (5) through an output joint fixing screw (8), and a gap is left between the output joint fixing screw (8) and the mass block (10).

3. A piezoelectric stack driven resonant diaphragm pump according to claim 1, characterized in that, The material of the diaphragm is beryllium bronze, a PDMS film, a kapton flexible film or a PET plastic film.

4. A piezoelectric stack driven resonant diaphragm pump according to claim 1, characterized in that, The diaphragm top rod (14) and the diaphragm (13) are bonded by epoxy, the pump base (12) and the diaphragm (13) are bonded by epoxy to ensure sealing, the pump cavity height plate (22), the shunt one-way plate (24) and the kapton film (27) are bonded by epoxy to ensure sealing.

5. A piezoelectric stack driven resonant diaphragm pump according to claim 1, characterized in that, The diaphragm top rod (14) and the positioning output head (15) are gap fitted, and the vertical height of the diaphragm (13) can be adjusted by tightening the clamp.

6. A piezoelectric stack driven resonant diaphragm pump according to claim 1, characterized in that, The piezoelectric stack material electric-mechanical converter (I) comprises a base (1), a shell (4) mounted on the base (1), a bushing (2) mounted in the shell (4), a piezoelectric stack material (3) mounted in the bushing (2), an output rod (5) mounted on the upper end of the piezoelectric stack material (3), an output connector (7) mounted on the upper end of the output rod (5), and a disc spring (6) for providing a restoring force to the output rod. The top of the shell (4) is further fixedly connected with a pre-tightening end cover (21), the output rod (5) penetrates the pre-tightening end cover (21), the disc spring (6) is sleeved on the output rod (5) and abuts between the stepped surface of the output rod (5) and the bottom surface of the pre-tightening end cover (21).

7. A piezoelectric stack driven resonant diaphragm pump according to claim 1, characterized in that, The support (III) comprises a plurality of studs (11), the bottom end of the stud (11) is threadedly connected to the top surface of the shell (4), the middle part of the stud (11) penetrates the mass block (10) and keeps separated therefrom, and the top end of the stud (11) is fixedly connected with the pump base (12).

8. A method of using a piezoelectric stack driven resonant diaphragm pump as defined in claim 1, characterized by, The specific steps are as follows: Step 1, calculate the resonance frequency f of the mechanical system of the resonance body composition, the calculation formula is: Wherein, K1 is the stiffness of the rectangular spring piece, m 质量块 is the mass of the mass block in the resonance body, the calculation formula of the stiffness of the rectangular spring piece: where b is the spring leaf width; E is the modulus of elasticity of the spring leaf material; h is the thickness; and / is the spring leaf length; Step 2, set the frequency of the driving signal for driving the piezoelectric stack material to the calculated resonance frequency f; Step 3, the piezoelectric stack material makes periodic elongation and shortening movement at the resonance frequency, drives the resonator to resonate, and makes the diaphragm move up and down at the resonance frequency f, thereby changing the volume inside the pump cavity; with the periodic change of the pump cavity volume, the oil pumping is completed.

Images