CN102817817A - Piezo-stack pump - Google Patents

Abstract

The invention discloses a piezoelectric stack pump, which comprises a pump base provided with a fluid inlet and a fluid outlet, a pump body, a pump upper cover and a piezoelectric stack accommodated in the pump body, one end of the piezoelectric stack is connected to the pump A vibrating piston is provided between the bases, and a pre-tightening piston is provided between the other end of the piezoelectric stack and the upper cover of the pump; the vibrating piston is pasted on the vibrating film, and a working force is formed between the vibrating film and the pump base. liquid cavity. All the components of the piezoelectric stack pump of the present invention are integrated into the pump body, saving space, each component is convenient to assemble, easy to process, and the working liquid chamber is strictly sealed to effectively prevent leakage and increase the output power. It can be widely used in the fields of automobile engine fuel supply and robots.

Description

A piezoelectric stack pump

technical field

The invention relates to a piezoelectric pump, in particular to a valved piezoelectric stack pump.

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Background technique

The research on piezoelectric pumps began in the 1980s. It is a fluid pump designed and manufactured based on the principle of piezoelectric drive. The piezoelectric pump does not need an additional drive motor, but uses the inverse piezoelectric effect of the piezoelectric material to apply an alternating current signal to the piezoelectric stack to cause the piezoelectric stack to expand and contract, and then the volume of the pump chamber changes due to the expansion and contraction deformation. Cooperate with the import and export check valve to control the direction of the fluid, so as to realize the fluid delivery. Since traditional piezoelectric pumps are mostly in the form of piezoelectric bimorphs, the advantages of this type of piezoelectric pump are simple structure, small size, light weight, low energy consumption, no electromagnetic interference and low cost, and are widely used in pharmaceutical , Medical, trace reagent ratio and chemical analysis and other fields. However, piezoelectric pumps of the piezoelectric sheet type or piezoelectric bimorph type have low output pressure and weak carrying capacity, which cannot meet the higher requirements for piezoelectric pumps at the present stage.

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Contents of the invention

technical problem

The technical problem to be solved by the invention is to provide a valve-type piezoelectric stack pump with compact structure and good output performance.

Technical solutions

In order to solve the above-mentioned technical problems, the piezoelectric stack pump of the present invention includes a pump base provided with a fluid inlet and a fluid outlet, a pump body, a pump upper cover, and a piezoelectric stack housed in the pump body. A vibrating piston is provided between one end of the stack and the pump base, and a pre-tightening piston is provided between the other end of the piezoelectric stack and the pump upper cover; the vibrating piston is pasted on the vibrating film, and the vibrating film and the A working fluid cavity is formed between the pump bases. The pump base, the pump body and the pump upper cover form a closed space, and the piezoelectric stack is accommodated in the space; the pump base is processed with a circular concave cavity, and the vibrating membrane vibrates the circular cavity. The concave cavity is sealed to form a working fluid cavity.

The vibrating membrane is arranged between the piezoelectric stack and the pump base. In order to ensure the sealing between the vibrating membrane and the circular concave cavity, a pressure ring fixed in another circular concave cavity will The vibrating membrane is compressed.

Furthermore, the pump upper cover is provided with a pair of preload screws for applying preload to the preload piston. Since the preload piston is in contact with the piezoelectric stack at the same time, when the preload screw applies preload When the tightening force is applied, that is, the pre-tightening force is applied to the piezoelectric stack, and the fine-tuning of the pre-tightening degree of the piezoelectric stack can be realized by fine-tuning the pre-tightening screw. The pump upper cover can also be processed with a circular concave cavity, and the pre-tightening piston is located in the circular concave cavity. Generally, in the piezoelectric stack pump of this technical solution, the pump body is a hollow structure with a cylindrical cavity, and the diameter of the preloaded piston is slightly smaller than the diameter of the inner cavity of the pump body and the diameter of the circular cavity of the pump upper cover. , to ensure that the preload piston is fixed circumferentially but can move up and down.

The pump body, the pump base and the pump upper cover are connected by screws, and the gaps between them are filled with sealing materials to ensure the overall sealing of the piezoelectric pump.

In order to facilitate the flow of fluid in the piezoelectric pump, the fluid inlet is provided with an inlet one-way valve, and the fluid outlet is provided with an outlet one-way valve.

In the piezoelectric stack pump of this technical solution, the vibrating membrane and the vibrating piston are pasted together. Under the action of an external AC signal, the piezoelectric stack drives the vibrating piston, and the vibrating piston then drives the vibrating membrane to move, and the deformation of the vibrating membrane is realized. The pump cavity is the change of the internal volume of the working liquid cavity, so that the pressure difference between the inside and outside of the pump cavity is generated, and the liquid inlet and outlet are controlled by the one-way valve at the liquid inlet and the one-way valve at the liquid outlet. When the volume of the working fluid chamber decreases and the pressure inside the working fluid chamber is greater than the external pressure, the passive valve of the liquid outlet opens and the fluid flows out; when the volume of the working liquid chamber increases, the pressure inside the working liquid chamber is The passive valve opens and fluid flows in, and so on to achieve a continuous one-way flow of fluid.

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Beneficial effect

In the piezoelectric stack of the present invention, all components can be integrated into the pump body, which saves the space required for design, is very compact, and each component is easy to assemble and easy to process. The working fluid chamber is strictly sealed to effectively prevent leakage. The output power is improved, and the problem of low output pressure and relatively weak carrying capacity of the double-chip piezoelectric pump is overcome. The output pressure can reach 5bar, and the maximum output flow can reach 350ml/min. Integrating the advantages of large output pressure, small volume and large carrying capacity of the present invention, the piezoelectric stack pump of the present invention can be widely used in the fields of automobile engine fuel supply and robotics, especially in the field of aerospace, when it is connected to the hydraulic cylinder Such actuators can convert the pressure fluid output into force output, and push the rudder surface of the aircraft to move.

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Instructions attached

Fig. 1 is the structural representation of an embodiment of the present invention;

Fig. 2 is a schematic structural view of a pump base according to an embodiment of the present invention;

Fig. 3 is a schematic diagram of the structure of the upper cover of the pump according to an embodiment of the present invention.

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Detailed ways

As shown in Fig. 1 and Fig. 2, the piezoelectric stack pump of this embodiment includes a pump base 11 provided with a fluid inlet 13 and a fluid outlet 12, a pump body 6, a pump upper cover 3 and a pump housed in the pump body 6. The piezoelectric stack 5, the fluid inlet 13 is provided with an inlet check valve 13, and the fluid outlet 12 is provided with an outlet check valve 12; the pump body 6 has a cylindrical cavity, and the piezoelectric stack 5 is accommodated in the cylindrical cavity Correspondingly, the piezoelectric stack 5 is also cylindrical. A vibrating piston 8 is provided between one end of the piezoelectric stack 5 and the pump base 11, and a preloaded piston 4 is provided between the other end of the piezoelectric stack 5 and the pump upper cover 3; the vibrating piston 8 is pasted on the vibrating On the membrane 10 , a working fluid cavity 14 is formed between the vibration membrane 10 and the pump base 11 .

Specifically, the vibrating membrane 10 is arranged between the vibrating piston 8 and the pump base 11 , and is pressed and fixed by a pressure ring 9 . In this embodiment, two circular concave cavities are processed on the pump base 11, one of which has a diameter of 35 mm and a height of 0.5 mm. The vibrating membrane 10 covers the opening of the circular concave cavity so that the cavity The body seal forms the working fluid cavity, that is, the working fluid cavity 14 is composed of the vibrating membrane 10 and the circular concave cavity seal on the pump base 11, and is connected with the fluid inlet and outlet. The height of the working fluid cavity is the circular concave cavity the height of. Another circular concave cavity has a diameter of 43 mm and a height of 5 mm. The pressure ring 9 cooperates with this circular concave cavity to compress the vibrating film 10. The sealing material such as Raw tape. As shown in FIG. 1 , the lower end of the pump body 6 is connected to the pump base 11 through four M6X25 hex socket head cap screws 7 .

As shown in Fig. 1 and Fig. 3, the pump upper cover 3 is provided with a M10X20 hexagon socket head cap screw which exerts a pre-tightening force on the pre-tightening piston 4, that is, the pre-tightening screw 1, and through the fine-tuning of the pre-tightening screw 1 The fine adjustment of the preload degree of the piezoelectric stack 5 can be realized, so as to obtain different pump working parameters. Correspondingly, as shown in Figure 2, the pump upper cover 3 is provided with an opening 31 for the pre-tightening screw 1 to pass through, and the side of the pump upper cover 3 facing the pump body 6 is a circular cavity 32 for accommodating the pre-tightening screw. Piston 4, the diameter of the preloaded piston 4 is slightly smaller than the diameter of the pump body, that is, the overall position of the preloaded piston 4 is relatively fixed through the cooperation of the preloaded screw 1 and the piezoelectric stack 5, but it can be adjusted due to the action of the vibrating piston 8 axial movement. The pump upper cover 3 is connected with the pump body through two M6X30 socket head cap screws 2 .

In this embodiment, the piezoelectric stack 5 has a diameter of 10 mm and a length of 90 mm. During operation, the adjustable voltage of the power supply is 0-150 V, and the frequency range is 40-200 Hz alternating current. With water as the experimental working medium, the maximum output pressure of the pump can reach 500Kpa.

The pump body 6, the pump base 11 and the pump upper cover 3 in this embodiment are made of aluminum or plexiglass, and the gaps between the parts are sealed; the vibrating membrane 10 is a copper sheet with a thickness of 0.2 mm and a diameter of 43 mm. It can also be made of other types of elastic materials.

When the piezoelectric stack pump in this embodiment is working, under the action of an external AC signal, the piezoelectric stack 5 drives the vibrating piston 8, and the vibrating piston 8 drives the vibrating membrane 10 to move up and down to deform the vibrating membrane 10. Realize the change of the internal volume of the working liquid chamber, so that the pressure difference between the inside and outside of the pump body 6 is generated, and the liquid in and out is controlled by the one-way valve at the liquid inlet and the one-way valve at the liquid outlet. When the volume of the working fluid chamber decreases, the pressure inside the working fluid chamber is greater than the external pressure, and the passive valve of the fluid outlet 12 opens, and the fluid flows out; when the volume of the working fluid chamber increases, the pressure inside the working fluid chamber is The passive valve of 13 is opened, and the fluid flows in, and so circulates to realize the continuous one-way flow of liquid.

Claims (7)

1. A piezoelectric stack pump, including a pump base (11) with a fluid inlet (13) and a fluid outlet (12), a pump body (6), a pump cover (3) and a pump body ( 6) The piezoelectric stack (5) inside is characterized in that a vibrating piston (8) is provided between one end of the piezoelectric stack (5) and the pump base (11), and the other end of the piezoelectric stack (5) There is a pre-tightening piston (4) between one end and the pump upper cover (3); the vibrating piston (8) is pasted on the vibrating film (10), and the vibrating film (10) and the pump base (11 ) to form a working liquid chamber (14). 2. The piezoelectric stack pump according to claim 1, characterized in that, the vibrating membrane (10) is arranged between the vibrating piston (8) and the pump base (11), and passes through a pressure ring ( 9) Press and fix. 3. The piezoelectric stack pump according to claim 1, characterized in that, the pump upper cover (3) is provided with a pair of pre-tightening pistons (4) to apply pre-tightening screws (1) for pre-tightening force. 4. The piezoelectric stack pump according to claim 1, 2 or 3, characterized in that the pump body (6) is a pump body with a cylindrical cavity. 5. The piezoelectric stack pump according to claim 4, characterized in that, the diameter of the preloaded piston (4) is smaller than that of the inner cavity of the pump body (6). 6. The piezoelectric stack pump according to claim 1, characterized in that, the pump body (6), the pump base (11) and the pump upper cover (3) are connected by screws. 7. The piezoelectric stack pump according to claim 1, characterized in that, the fluid inlet (13) is provided with an inlet check valve, and the fluid outlet (12) is provided with an outlet check valve.

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