Piezoelectric direct-drive high-speed switch valve with separated valve element and control method of piezoelectric direct-drive high-speed switch valve

Abstract

The invention discloses a piezoelectric direct-drive high-speed switch valve with a separated valve element and a control method of the piezoelectric direct-drive high-speed switch valve, and relates to the technical field of digital switch valves. According to the piezoelectric direct-drive high-speed switch valve, the requirement for high frequency response is met, meanwhile, the two-position three-way cone valve element structure is used for the piezoelectric direct-drive high-speed switch valve according to the design concept of the separation cone valve element, and zero leakage and high pressure of the high-speed switch valve are achieved on the basis that the machining, assembling and debugging cost is not increased. Comprising an electro-mechanical converter and a hydraulic control valve. The electro-mechanical converter comprises an upper end cover, a piezoelectric output mechanism, an output rod, a disc spring and a shell; the hydraulic control valve comprises the two-position three-way cone valve element and a valve sleeve. The piezoelectric stack direct drive and separated cone valve element structure is utilized, the machining, assembling and debugging difficulty of the two-position three-way cone valve element high-speed switch valve is lowered, and the two-position three-way cone valve element high-speed switch valve has the advantages of being free of leakage, resistant to high pressure and high in frequency response.

Description

Technical Field

[0001] The present invention relates to the technical field of digital switch valves, and in particular to a piezoelectric direct-drive high-speed switch valve with a separated valve core. Background Art

[0002] In recent years, with the rapid development of digitalization and intelligentization, digital hydraulic technology with high frequency response, high control precision, high stability, and high flexibility has gradually become a new development trend in hydraulic technology. As a key core component of digital hydraulic technology, the superior performance of high-speed switching valves directly affects the performance of digital hydraulic systems. Traditional electromagnetic high-speed switching valves are affected by factors such as electromagnetic hysteresis and mechanical hysteresis, which limits their response speed. As a result, their pressure and flow control accuracy cannot meet the high-frequency response and high-resolution control requirements of digital hydraulic technology. Due to the small output displacement of high-speed switching valves based on intelligent materials, when using a two-position three-way valve core configuration, in order to achieve zero leakage, it greatly increases the difficulty of processing, assembly, and debugging. Summary of the Invention

[0003] In response to the above problems, the present invention proposes a piezoelectric direct-driven high-speed switching valve with a separated valve core and a control method thereof. While meeting the high-frequency response requirements, the design concept of a separated cone valve core is adopted, and a two-position three-way cone valve core configuration is used for a piezoelectric direct-driven high-speed switching valve. Without increasing the processing, assembly and debugging costs, zero leakage and high pressure of the high-speed switching valve are achieved.

[0004] The technical solution of the present invention is as follows: comprising an electro-mechanical converter and a hydraulic control valve; The electromechanical converter includes an upper end cover 1, a piezoelectric output mechanism, an output rod 4, a disc spring 5, and a housing 12. The upper end cover 1 is fixedly mounted on one end of the housing 12, and the output rod 4 is telescopically arranged at the other end of the housing 12. The piezoelectric output mechanism is positioned between the upper end cover 1 and the output rod 4, and outputs a linear driving force between the two. The hydraulic control valve includes the two-position three-way cone valve core and a valve sleeve 13. The valve sleeve 13 is fixedly installed at one end of the housing 12. The disc spring 5 is pressed between the valve sleeve 13 and the output rod 4. The two-position three-way cone valve core is installed in the valve sleeve 13 and is fixedly connected to the output rod 4. An oil inlet cavity, a working oil cavity and an oil outlet cavity are sequentially provided inside the valve sleeve 13. The side walls of the three are sequentially provided with an oil inlet port P, a working oil port A and an oil outlet T. The inner diameter of the working oil cavity in the middle is smaller than the working oil cavity of the oil inlet cavity and the oil outlet, thereby forming a first throttling edge and a second throttling edge at both ends of the working oil cavity. When the two-position three-way cone valve core is attached to the first throttling edge, the oil inlet cavity and the working oil cavity remain cut off. When the two-position three-way cone valve core is attached to the second throttling edge, the oil outlet cavity and the working oil cavity remain cut off.

[0005] About the specific structure inside the electro-mechanical converter: The piezoelectric output mechanism includes a first annular piezoelectric stack 2, a second annular piezoelectric stack 3, a square piezoelectric stack 11, and a sleeve 10 for connection. One end of the sleeve 10 is sealed, and the outer wall of the other end has an annular boss. The first annular piezoelectric stack 2 and the second annular piezoelectric stack 3 are axially stacked and nested outside the sleeve 10 and abut against the annular boss; the square piezoelectric stack 11 axially penetrates into the sleeve 10 and abuts against the sealed end of the sleeve 10.

[0006] Furthermore, an upper anti-twist end cover 9 is provided between the upper end cover 1 and the piezoelectric output mechanism. Both the upper anti-twist end cover 9 and the output rod 4 have the following anti-twist structures: A rectangular protrusion is provided on the side wall of the upper anti-twist end cover 9, and a rectangular slide is provided on the upper portion of the inner wall of the housing 12, wherein the rectangular protrusion is slidably connected in the rectangular slide; A rectangular protrusion is also provided on the side wall of the output rod 4 , and a rectangular sliding groove is also provided on the lower portion of the inner wall of the housing 12 , in which the rectangular protrusion is slidably connected.

[0007] Furthermore, an adjusting screw 8 is installed through the upper end cover 1, and the adjusting screw 8 is threadedly connected to the upper end cover 1 and presses against the upper anti-twist end cover 9, thereby adjusting the initial pressure of the disc spring 5 and the initial position of the upper separation cone valve core 6 and the lower separation cone valve core 7.

[0008] About the specific structure inside the hydraulic control valve: The two-position three-way cone valve core includes an upper separation cone valve core 6 and a lower separation cone valve core 7. The upper separation cone valve core 6 and the lower separation cone valve core 7 are installed through the valve sleeve 13, and the output rod 4, the upper separation cone valve core 6, and the lower separation cone valve core 7 are fixedly connected in sequence; The upper separation cone valve core 6 is in the shape of a stepped shaft with a larger upper portion and a smaller lower portion, and its stepped surface is in the shape of a cone. The large shaft of the upper separation cone valve core 6 is accommodated in the oil inlet cavity, and its small shaft passes through the working oil cavity. The lower separation cone valve core 7 is accommodated in the oil outlet cavity and is fixedly mounted on the small shaft of the upper separation cone valve core 6. The top surface of the lower separation cone valve core 7 is in the shape of a cone. When the step surface of the upper separation cone valve core 6 fits the first throttling edge, the oil inlet cavity and the working oil cavity remain cut off; when the top surface of the lower separation cone valve core 7 fits the second throttling edge, the oil outlet cavity and the working oil cavity remain cut off, and the distance between the step surface of the upper separation cone valve core 6 and the top surface of the lower separation cone valve core 7 is greater than the distance between the first throttling edge and the second throttling edge.

[0009] Furthermore, the lower separation cone valve core 7 is mounted on the bottom end of the upper separation cone valve core 6, and a hexagonal adjusting screw 16 is installed through the lower separation cone valve core 7. The hexagonal adjusting screw 16 is threadedly connected to the upper separation cone valve core 6, and a valve core separation disc spring 15 is also mounted on the hexagonal adjusting screw 16, which is pressed between the lower separation cone valve core 7 and the upper separation cone valve core 6, so that the upper separation cone valve core 6 and the lower separation cone valve core 7 maintain the state adjusted by the hexagonal adjusting screw 16.

[0010] The control method of the piezoelectric direct-drive high-speed on-off valve with valve core separation provided by the present invention adopts the following technical solutions: A PWM voltage signal with a maximum amplitude of 110V DC is generated by a control pair for the piezoelectric direct-drive high-speed switching valve power amplifier and is applied to the two annular piezoelectric stacks and one square piezoelectric stack. The annular piezoelectric stack and the directional piezoelectric stack are excited by the DC voltage to generate axial deformation and output force, so that the output rod overcomes the compressive force of the disc spring and pushes the two-position three-way separation cone valve core to move, so that the valve core state of the piezoelectric direct-drive high-speed switching valve with valve core separation changes, that is, the working state in which the working oil chamber communicates with the return oil chamber is changed to the working state in which the working oil chamber communicates with the oil inlet chamber.

[0011] The electro-mechanical converter in the present invention utilizes piezoelectric stack materials with large output force and high frequency response to solve the problem of limitations in improving the response speed of electromagnetic switch valves due to magnetic field hysteresis and mechanical hysteresis. The two-position three-way valve core of the hydraulic control valve adopts a separated zero-leakage cone valve core structure based on the separation design concept. The relative position of the cone surface of the two-position three-way valve core can be adjusted by the hexagonal screw, solving the problem of difficulty in processing, assembly and debugging caused by the small displacement of the valve core of the piezoelectric direct-drive high-speed switch valve. In addition, the upper and lower cone valve cores of the two-position three-way cone valve core are of the same diameter, which has the special effect of balancing the liquid pressure and reducing the driving force of the valve core, so that the high-speed switch valve has the characteristics of high pressure resistance. The present invention utilizes piezoelectric stack direct drive and separate cone valve core structure to reduce the difficulty of processing, assembly and debugging of the two-position three-way cone valve core high-speed switch valve, and has the characteristics of zero leakage, high pressure resistance and high frequency response. The beneficial effects of the present invention are: 1. The present invention uses piezoelectric stack materials as the motor converter of the high-speed switching valve, overcoming the problem of the limitation of the response speed improvement caused by electromagnetic hysteresis and mechanical hysteresis of the traditional electromagnetic high-speed switching valve, and further improving the response speed of the high-speed switching valve.

[0012] 2. The two-position three-way valve core of the present invention adopts a separated cone valve core structure, which reduces the difficulty of processing, assembling and debugging the piezoelectric direct-driven two-position three-way high-speed switching valve.

[0013] 3. The two-position three-way separation cone valve core of the present invention is designed to have the same outer circle as the cone valve core configuration, and is a piezoelectric direct-driven two-position three-way high-speed switch with the characteristics of zero leakage and high pressure resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 2. It is a schematic structural diagram of a piezoelectric direct-drive high-speed switching valve with a separated valve core according to an embodiment of the present invention; FIG2 is a schematic diagram of the working state of the piezoelectric direct-drive high-speed switching valve with valve core separation according to an embodiment of the present invention, wherein Figure 2a This is a schematic diagram of the working state where the oil inlet P is connected to the working port A. Figure 2b This is a schematic diagram of the working state where the working port A is connected to the oil return port T; FIG3 is a schematic diagram of a typical workpiece structure of a piezoelectric direct-drive high-speed switching valve with valve core separation according to an embodiment of the present invention, wherein Figure 3a This is a schematic diagram of the upper end cover. Figure 3b This is a schematic diagram of the upper anti-twist end cover. Figure 3c Figure 3 is a schematic diagram of the output rod, and Figure 3d is a schematic diagram of the separation cone valve core. DETAILED DESCRIPTION

[0015] In order to clearly illustrate the technical features of this patent, this patent is described in detail below through specific implementation methods and in combination with its accompanying drawings.

[0016] like Figure 1 As shown in Figures 2 and 3, this embodiment proposes a piezoelectric direct-drive high-speed switching valve with valve core separation, including an upper end cover 1, a first annular piezoelectric stack 2, a second annular piezoelectric stack 3, an output rod 4, a disc spring 5, an upper separation cone valve core 6, a lower separation cone valve core 7, an adjusting nut 8, an upper anti-twist end cover 9, a sleeve 10, a square piezoelectric stack 11, a shell 12, a valve body 13, an O-ring 14, a separation disc spring 15 and a hexagonal adjusting screw 16.

[0017] In this embodiment, the upper end cover 1 is mounted on the upper end surface of the housing 12, and adopts a threaded connection structure, which is conducive to reducing the wall thickness of the housing 12 and achieving maximum utilization of the space of the housing 12. In addition, the upper end cover 1 is designed with four cylindrical through holes with a diameter of 4 mm (such as Figure 3a As shown), it is convenient to install the upper end cover 1 using circlip pliers.

[0018] The first annular piezoelectric stack 2 and the second annular piezoelectric stack 3 are axially stacked and nested in the outer circle of the sleeve 10, and the square piezoelectric stack 11 is nested in the inner circle of the sleeve 10, together forming a new type of "axial stacking" and "radial nesting" structure piezoelectric motor converter, so that the motor converter constituting the piezoelectric direct-drive high-speed switching valve can amplify the output displacement of the piezoelectric stack while taking into account the large output force, thereby reducing the axial size of the motor converter, which is conducive to the miniaturization of the piezoelectric direct-drive high-speed switching valve.

[0019] In order to better use this embodiment, the upper anti-twist end cap 9 and the output rod 4 are designed with a pair of protruding rectangular structures, such as Figure 3b and 3c As shown, they are located on the upper end surface of the first annular piezoelectric stack 2 and the lower end surface of the square piezoelectric stack 11. During installation, this structure is aligned with the rectangular slotted axis on the housing 12, limiting the axial rotation of the upper anti-twist end cap 9 and the output rod 7, protecting the annular piezoelectric stack 2, the second annular piezoelectric stack 3, and the square piezoelectric stack 11 from torsional torque during operation, and thus extending the service life of the piezoelectric stack material.

[0020] The two-position, three-way valve core of the piezoelectric direct-drive high-speed on-off valve with a separated valve core utilizes a split valve core structure, consisting of an upper separated cone valve core 6 and a lower separated cone valve core 7, each having the same outer diameter. This split structure solves the challenges of high valve core machining precision and complex assembly and commissioning due to the small output displacement of the piezoelectric stack material. The conical valve core configuration achieves zero leakage in the piezoelectric direct-drive high-speed on-off valve. The upper and lower separated cone valve cores use the same outer diameter to balance the hydraulic pressure acting on the valve core, making the opening and closing dynamic characteristics of the piezoelectric direct-drive high-speed on-off valve unaffected by the operating pressure, thereby achieving high-pressure resistance and highly stable output.

[0021] The upper separation cone valve core 6 is located at the lower end face of the output rod 4 and is rigidly connected via a threaded structure. The upper separation cone valve core 6 and the valve body 13, the upper separation cone valve core 6 and the lower separation cone valve core 7, and the lower separation cone valve core 7 and the valve body 13 all use the O-ring 14, so that the upper and lower separation cone valve cores 6 and the lower separation cone valve core 7, the first throttling edge and the second throttling edge of the valve body 13 form an oil inlet cavity, a working oil cavity and an oil outlet cavity. It should be noted that the lower separation cone valve core is also designed with an inner hexagonal hole to facilitate the installation of the lower separation cone valve core 6 and the output rod 4, as shown in FIG. Figure 3d shown.

[0022] The adjusting nut 8 is in close contact with the upper end surface of the upper anti-twist end cap 9 through the threaded hole of the upper end cap 1. Adjustment of the adjusting nut 8 enables the output rod 4 and the upper separation cone valve core 6 to move up and down, thereby adjusting and controlling the relative position between the conical surface of the upper separation cone valve core 6 and the first throttling edge of the valve body 13.

[0023] The adjusting disc spring 5 is located in a composite configuration between the output rod 4 and the valve body 13, and together with the adjusting screw 8, forms a displacement-force conversion system. By adjusting the adjusting screw 8, the disc spring 5 converts the displacement of the output rod 4 into force, thereby adjusting the preload force of the annular and square piezoelectric stacks. Furthermore, after the motor converter is powered off, the compressive force of the disc spring 5 also acts as the driving force for the upper and lower separation cone valve cores 6 and 7, and the output rod 4, to return to their initial displacement.

[0024] Similarly, the valve core separation disc spring 15 located between the upper and lower separation cone valve cores and the hexagonal adjusting screw 16 passing through the lower separation cone valve core and connected to the upper separation cone valve core by a thread constitute a displacement-force conversion system. By adjusting the hexagonal adjusting screw 16, the relative positions of the upper separation cone valve core 6 and the lower separation cone valve core 7 can be adjusted, and the valve core separation disc spring 15 converts the displacement of the hexagonal adjusting screw 16 into disc spring compression force and acts on the upper separation cone valve core 6 and the lower separation cone valve core 7, so that the upper separation cone valve core 6 and the lower separation cone valve core 7 maintain the state adjusted by the hexagonal adjusting screw 16.

[0025] The working principle of the present invention is as follows: like Figure 2a As shown, when the first annular piezoelectric stack 2, the second annular piezoelectric stack 3, and the square piezoelectric stack 11 are not receiving voltage excitation, the output rod 4 is in its upper limit position due to the pre-compression force of the regulating disc spring 5. Similarly, because the upper and lower separation cone valve cores 6 and 7 are rigidly connected to the output rod 4, they are also in their upper limit positions. The conical surface of the lower separation cone valve core 7 is in close contact with the second throttling edge of the valve body 13, while the conical surface of the upper separation cone valve core 6 and the first throttling edge of the valve body 12 form a throttling orifice, allowing the oil inlet P to communicate with the working oil port A, while the working oil port A does not communicate with the oil return port T.

[0026] like Figure 2bAs shown, when the first annular piezoelectric stack 2, the second annular piezoelectric stack 3, and the square piezoelectric stack 11 are excited by voltage, they generate axial deformation and output force. When the axial output force generated by the first annular piezoelectric stack 2, the second annular piezoelectric stack 3, and the square piezoelectric stack 11 exceeds the pre-compression force of the adjusting disc spring 5, the output rod 4 is pushed downward. As the voltage excitation signal continues, the output rod 4 will continue to move downward until it reaches the lower limit position. Similarly, since the upper separation cone valve core 6 and the lower separation cone valve core 7 are rigidly connected to the output rod 4, the upper separation cone valve core 6 and the lower separation cone valve core 7 move to the lower limit position together with the output rod 4 - the conical surface of the upper separation cone valve core 6 is in close contact with the first throttling edge of the valve body 13, and the conical surface of the lower separation cone valve core 7 and the second throttling edge of the valve body 13 form a throttling port, causing the channel between the oil inlet port P and the working oil port A to be closed, and the channel between the working oil port A and the oil return port T to be open.

[0027] There are many specific implementation ways of the present invention. The above is only the preferred implementation method of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be considered as the scope of protection of the present invention.

Claims

1. A piezoelectric direct-drive high-speed switching valve with valve core separation, characterized in that: Including electro-mechanical converter and hydraulic control valve; The electromechanical converter comprises an upper end cover (1), a piezoelectric output mechanism, an output rod (4), a disc spring (5) and a housing (12), wherein the upper end cover (1) is fixedly mounted on one end of the housing (12), the output rod (4) is telescopically arranged on the other end of the housing (12), and the piezoelectric output mechanism is positioned between the upper end cover (1) and the output rod (4) and outputs a linear driving force between the two. The hydraulic control valve comprises a two-position three-way cone valve core and a valve sleeve (13), wherein the valve sleeve (13) is fixedly mounted on one end of a housing (12), the disc spring (5) is abutted between the valve sleeve (13) and the output rod (4), and the two-position three-way cone valve core is installed through the valve sleeve (13) and is fixedly connected to the output rod (4); an oil inlet cavity, a working oil cavity and an oil outlet cavity are sequentially provided inside the valve sleeve (13), and an oil inlet (P), a working oil cavity (A) and an oil outlet (T) are sequentially provided on the side walls of the three, and the inner diameter of the working oil cavity in the middle is smaller than that of the oil inlet cavity and the working oil cavity of the oil outlet, thereby forming a first throttling edge and a second throttling edge at both ends of the working oil cavity; when the two-position three-way cone valve core is attached to the first throttling edge, the oil inlet cavity and the working oil cavity are kept cut off, and when the two-position three-way cone valve core is attached to the second throttling edge, the oil outlet cavity and the working oil cavity are kept cut off.

2. The piezoelectric direct-drive high-speed switching valve with valve core separation according to claim 1, characterized in that: The piezoelectric output mechanism comprises a first annular piezoelectric stack (2), a second annular piezoelectric stack (3), a square piezoelectric stack (11), and a sleeve (10) for connection, wherein one end of the sleeve (10) is sealed and the outer wall of the other end has an annular boss; The first annular piezoelectric stack (2) and the second annular piezoelectric stack (3) are axially stacked and nested outside the sleeve (10) and abut against the annular boss; the square piezoelectric stack (11) is axially inserted into the sleeve (10) and abuts against the sealed end of the sleeve (10).

3. The piezoelectric direct-drive high-speed switching valve with valve core separation according to claim 1, characterized in that: An upper anti-twist end cover (9) is further provided between the upper end cover (1) and the piezoelectric output mechanism, and both the upper anti-twist end cover (9) and the output rod (4) have the following anti-twist structures: A rectangular protrusion is provided on the side wall of the upper anti-twist end cover (9), and a rectangular slide groove is provided on the upper portion of the inner wall of the housing (12), wherein the rectangular protrusion is slidably connected in the rectangular slide groove; A rectangular protrusion is also provided on the side wall of the output rod (4), and a rectangular sliding groove is also provided on the lower portion of the inner wall of the housing (12), and the rectangular protrusion is slidably connected in the rectangular sliding groove.

4. The piezoelectric direct-drive high-speed switching valve with valve core separation according to claim 3, characterized in that: An adjusting screw (8) is installed through the upper end cover (1), and the adjusting screw (8) is threadedly connected to the upper end cover (1) and abuts against the upper anti-twist end cover (9), thereby adjusting the initial pressure of the disc spring (5) and the initial positions of the upper separation cone valve core (6) and the lower separation cone valve core (7).

5. The piezoelectric direct-drive high-speed switching valve with valve core separation according to claim 1, characterized in that: The two-position three-way cone valve core comprises an upper separation cone valve core (6) and a lower separation cone valve core (7), wherein the upper separation cone valve core (6) and the lower separation cone valve core (7) are installed through the valve sleeve (13), and the output rod (4), the upper separation cone valve core (6), and the lower separation cone valve core (7) are fixedly connected in sequence; The upper separation cone valve core (6) is in the shape of a stepped shaft with a larger upper portion and a smaller lower portion, and its stepped surface is in the shape of a cone. The large shaft of the upper separation cone valve core (6) is accommodated in the oil inlet cavity, and its small shaft passes through the working oil cavity. The lower separation cone valve core (7) is accommodated in the oil outlet cavity and is fixedly mounted on the small shaft of the upper separation cone valve core (6). The top surface of the lower separation cone valve core (7) is in the shape of a cone. When the step surface of the upper separation cone valve core (6) is in contact with the first throttling edge, the oil inlet cavity and the working oil cavity are kept cut off; when the top surface of the lower separation cone valve core (7) is in contact with the second throttling edge, the oil outlet cavity and the working oil cavity are kept cut off; and the distance between the step surface of the upper separation cone valve core (6) and the top surface of the lower separation cone valve core (7) is greater than the distance between the first throttling edge and the second throttling edge.

6. The piezoelectric direct-drive high-speed switching valve with valve core separation according to claim 5, characterized in that: The lower separation cone valve core (7) is mounted on the bottom end of the upper separation cone valve core (6), and a hexagonal adjusting screw (16) is installed through the lower separation cone valve core (7). The hexagonal adjusting screw (16) is threadedly connected to the upper separation cone valve core (6). A valve core separation disc spring (15) is also mounted on the hexagonal adjusting screw (16) and is pressed between the lower separation cone valve core (7) and the upper separation cone valve core (6), so that the upper separation cone valve core (6) and the lower separation cone valve core (7) maintain the state adjusted by the hexagonal adjusting screw (16).

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