CN101813197A - Flow control valve - Google Patents

Abstract

The invention provides a flow control valve, which can be used for flow control in an exhaust gas recirculation pipeline of an internal combustion engine. The flow control valve is provided with a pipe communicating the pipeline, wherein a rotary plate for blocking the pipe is arranged along the vertical direction of the pipe; at least one opening is reserved on the rotary plate; the rotary plate can rotate to the position where the opening and the pipe are superposed; the diameter of the opening is not greater than the outer diameter of the pipe; and a drive mechanism can drive the rotary plate to rotate around the axis of a rotating shaft and the drive mechanism can be a piezoelectric drive mechanism. The flow control valve has the advantages of compact and simple structure, smart size, low energy consumption, low noise and easy and accurate flow adjustment.

Description

A flow control valve

technical field

The invention relates to a flow control valve, in particular to a flow control valve which can be used in an exhaust gas recirculation pipeline of an internal combustion engine.

Background technique

The harmful emissions of the engine are a major source of air pollution. In order to reduce harmful gas emissions, an exhaust gas recirculation (EGR) system is usually installed on the internal combustion engine, which recirculates a part of the exhaust gas from the exhaust passage to the intake passage to reduce engine emissions. The EGR system can effectively reduce the combustion temperature of the engine, thereby effectively reducing the content of toxic substances such as nitrogen oxides in exhaust gas.

The EGR system mainly includes an exhaust gas recirculation pipeline and an exhaust gas recirculation valve, the exhaust gas recirculation pipeline is used to guide the exhaust gas from the exhaust passage to recirculate into the intake passage. An exhaust gas recirculation valve is usually arranged in the recirculation pipeline for controlling the recirculated exhaust gas flow. A typical exhaust gas recirculation valve is a valve driven by the movement of a valve stem driven by a driving device. Common driving methods are: electromagnetic drive, stepper motor drive, DC motor drive and torque motor drive. However, the structure of the existing exhaust gas recirculation valve is relatively complicated, the electromagnetic drive is susceptible to magnetic field interference, the stepper motor drive requires more magnetic poles, and the DC motor drive requires a gearbox to reduce speed and increase torque.

US 4473056 A discloses a motor driven exhaust gas recirculation valve. Its valve body is controlled and operated by a motor. The positioning screw and steel ball help the rotation of the motor output shaft to be converted into the vertical movement of the valve stem, and its structure is relatively complicated. US 4840350 A discloses an exhaust gas recirculation valve driven by a torque motor. Although the lead screw is eliminated and high flow control accuracy is provided, the disadvantage of the torque motor itself is low efficiency and high cost.

A piezoelectric motor is a type of motor that appeared in the 1970s and usually consists of a rotor, a stator, a drive and a control device. Piezoelectric motors usually use piezoelectric sheets and elastic metals as stators, apply high-frequency AC voltage to the piezoelectric sheets to excite the piezoelectric sheets, and use the inverse piezoelectric effect of the piezoelectric sheets to cause alternating periodic stretching deformations of the piezoelectric sheets , the linkage elastic metal produces vibration, so that the rotor in contact with it moves under the action of friction. For the working principle of piezoelectric motors, please refer to "Theoretical and Experimental Research on Rotary Traveling Wave Ultrasonic Motors" (China Excellent Doctoral and Master's Dissertations Full-text Database (Master), author Zhao Bing, 2006, pages 10, 11, 15-20) .

Contents of the invention

The technical problem to be solved by the present invention is to provide a flow control valve to overcome the defects of electromagnetic drive, stepping motor drive, DC motor drive and torque motor drive.

A specific technical problem to be solved by the present invention is to provide a flow control valve, which has a simple structure, is easy to operate, and has high control precision.

Another specific technical problem to be solved by the present invention is to provide a flow control valve, which is free from magnetic field interference, compact and simple in structure, small in size, easy to precisely adjust flow and low in cost.

Specifically, in one form of the present invention, the operating principle of a piezoelectric motor is utilized to provide a drive mechanism for a flow control valve that can be used to control the flow of fluid in a pipeline.

In order to solve the above-mentioned technical problems, in one form of the present invention, a flow control valve is provided, which has a pipeline through which fluid passes, wherein a rotating piece is arranged along the vertical direction of the pipeline to cut off the pipeline, so that The rotating piece is provided with at least one opening, and the rotating piece can be rotated to a position where the opening coincides with the pipe, and the diameter of the opening is not larger than the outer diameter of the pipe.

Preferably, the rotating piece is in sealing contact with the duct wall of the duct.

Preferably, the rotating piece and the pipe are hermetically arranged in a housing, and the two ends of the pipe protrude out of the housing.

Preferably, the rotating piece can rotate around the axis of a rotating shaft driven by a driving mechanism.

Preferably, the driving mechanism includes a stator, at least one piezoelectric device and at least one piece of friction material, the piezoelectric device is arranged on one of the stator and the rotating piece, and the piece of friction material passes through An elastic member is tightly pressed between the stator and the rotating piece.

Preferably, the stator is a casing supporting and accommodating the rotating piece and the pipe, and the two ends of the pipe protrude outside the casing.

Preferably, the elastic member is arranged around the rotating shaft of the rotating piece, and presses the rotating piece toward the stator along the axial direction of the rotating shaft.

Preferably, the rotating piece is composed of two opposite sector-shaped parts, the opening is provided in the first sector-shaped part, and the second sector-shaped part is pressed against the friction material sheet.

Preferably, the piezoelectric device includes a piezoelectric sheet and a control circuit.

Preferably, one of the rotating piece and the stator is provided with a boss, and the boss is in contact with the friction material sheet.

Preferably, the friction material sheet is arranged on the stator, and the piezoelectric device is arranged on the rotating sheet.

In another form of the invention there is provided a flow control valve for flow control in an exhaust gas recirculation line of an internal combustion engine, the flow control valve having a conduit communicating with said line, wherein along said In the vertical direction of the pipeline, there is a rotating piece that cuts off the pipeline. The rotating piece is provided with at least one opening. The rotating piece can be rotated to a position where the opening coincides with the pipeline. The opening diameter is not greater than the outer diameter of the pipe.

Preferably, the rotating piece can rotate around the axis of a rotating shaft driven by a driving mechanism, the driving mechanism includes a stator, at least one piezoelectric device and at least one piece of friction material, and the piezoelectric device is arranged on On one of the stator and the rotating piece, the friction material sheet is tightly pressed between the stator and the rotating piece through an elastic member.

Preferably, the stator is a casing supporting and accommodating the rotating piece and the pipe, and the two ends of the pipe protrude outside the casing.

Preferably, the elastic member is arranged around the rotating shaft of the rotating piece, and presses the rotating piece toward the stator along the axial direction of the rotating shaft.

Preferably, the rotating piece is composed of two opposite sector-shaped parts, the opening is provided in the first sector-shaped part, and the second sector-shaped part is pressed against the friction material sheet.

Preferably, the piezoelectric device includes a piezoelectric sheet and a control circuit.

Preferably, one of the rotating piece and the stator is provided with a boss, and the boss is in contact with the friction material sheet.

Preferably, the friction material sheet is arranged on the stator, and the piezoelectric device is arranged on the rotating sheet.

In the present invention, the driving mechanism of the flow control valve can be set based on the principle of the piezoelectric motor, so it has the advantages of the piezoelectric motor, specifically:

The rotating plate in the present invention is not only the rotor of the piezoelectric drive mechanism, but also the control plate for controlling the flow rate of the valve. The exhaust gas flow in the pipe depends on the overlapping area of the openings on the rotor and the pipe. Because the rotating plate is driven by the high-frequency and small-amplitude vibration excited by the piezoelectric sheet, the flow rate of the exhaust gas recirculation can be accurately controlled.

Due to the inherently high torque-to-speed ratio of piezoelectric actuation, the flow control valve of the present invention is capable of providing sufficient torque without the need for mechanical components such as gearboxes. Piezoelectric drive has a large output torque at low speed and can directly drive the load. Generally, if the common electromagnetic motor wants to achieve the characteristics of large output torque at low speed, it usually needs to add a gear transmission mechanism to reduce the speed. It can be achieved; and the piezoelectric drive can directly drive the load without such a reduction mechanism, which not only reduces the weight and volume of the reduction mechanism, but also avoids problems such as vibration, impact and noise generated by the gear transmission mechanism.

The flow control valve of the invention has a simpler and more compact structure. Compared with the piezoelectric motor, the rotating plate of the present invention only rotates within a fan-shaped area, instead of continuously rotating like the rotating plate of the piezoelectric motor. Piezoelectric motors usually have piezoelectric devices on the stator, which can avoid the use of brushes. In the present invention, the piezoelectric device can be arranged on the stator or on the rotating piece, and the use of brushes can be avoided, thereby improving the reliability of the flow control valve of the present invention.

The holding torque of the general electromagnetic motor is small, after the power is cut off, the motor will not stop immediately because the inertial force is greater than the holding torque. The flow control valve of the present invention is driven by traveling wave friction coupling between the rotating plate and the stator. Due to the high holding torque provided by the friction force, the rotating plate of the valve of the present invention can maintain a precise position without consuming extra energy.

Because the flow control valve of the present invention is driven by piezoelectricity, it is free from magnetic field interference and has lower noise than the existing methods such as electromagnetic drive and DC motor drive.

Description of drawings

The following drawings are only intended to illustrate and explain the present invention schematically, and do not limit the scope of the present invention. in,

1 is a schematic cross-sectional view of a flow control valve according to a specific embodiment of the present invention;

Fig. 2a is a schematic diagram when the opening of the rotating piece and the pipe completely overlap according to a specific embodiment of the present invention;

Fig. 2b is a schematic diagram when the opening of the rotating piece coincides with the pipe part according to a specific embodiment of the present invention;

Fig. 2c is a schematic diagram according to a specific embodiment of the present invention when the opening of the rotating piece does not coincide with the pipe.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings. Wherein, the same parts adopt the same reference numerals.

Fig. 1 is a schematic cross-sectional view of a flow control valve according to a specific embodiment of the present invention. As shown in the figure, the flow control valve 1 of this embodiment has a pipeline 100 for fluid to pass through, and a rotating piece 107 for cutting off the pipeline 100 is arranged along the vertical direction of the pipeline 100. The pipe 100 overlaps the opening 109 , wherein the diameter of the opening 109 is not larger than the outer diameter of the pipe 100 .

It can be seen from the figure that the pipeline 100 is actually composed of two parts separated by the rotating piece 107, and the rotating piece 107 is vertically inserted between the two parts. In order to prevent fluid from leaking from the contact surface between the pipe 100 and the rotating piece 107 , the rotating piece 107 is in sealing contact with the pipe wall of the pipe 100 . Depending on the nature of the fluid, a certain sealing device (not shown) may also be provided on the contact surface between the pipe 100 and the rotating piece 107, for example, a rubber sealing sleeve is provided on the pipe wall. In addition, in order to protect the internal parts of the flow control valve 1, the rotating piece 107 and the pipe 100 can also be sealed and arranged in a housing 105. Pipelines, such as exhaust gas recirculation pipes, etc. The casing 105 can also play a certain sealing role when the contact surface between the pipe 100 and the rotating piece 107 leaks.

The rotating piece 107 can rotate around the axis of a rotating shaft 102 driven by a driving mechanism 2 . Wherein, the rotating shaft 102 is supported by the bearing 101 on the casing 105 , and the rotating shaft 102 can rotate around its axis together with the rotating piece 107 . Of course, the rotating piece 107 can also be installed on the rotating shaft 102 through bearings, the rotating shaft 102 is fixedly installed relative to the housing 105, the rotating piece 107 can rotate around the axis of the rotating shaft 102, and the rotating shaft 102 remains stationary relative to the rotating piece 107.

The drive mechanism 2 can be a manual drive mechanism installed on the rotating shaft 102, a mechanical transmission mechanism, a stepping motor, or a drive mechanism that directly drives the rotating piece 107, such as the piezoelectric drive shown in Figure 1 mechanism.

As shown in FIG. 1 , the drive mechanism 2 includes a casing 105 as a stator 105', at least one piezoelectric device 12 disposed on a rotating piece 107, and at least one piece of frictional material 108. Wherein, the friction material sheet 108 is arranged on the housing 105 and pressed tightly between the housing 105 and the rotating piece 107 by an elastic member 103 . The elastic member 103 is arranged around the rotating shaft 102 of the rotating piece 107 , presses the rotating piece 107 toward the housing 105 along the axial direction of the rotating shaft 102 , and presses against the friction material sheet 108 tightly.

The rotating piece 107 is provided with a boss on the side that is connected with the friction material sheet 108. The setting of the boss reduces the contact area with the friction material sheet 108 on the one hand, and can also eliminate the contact between the rotating piece 107 and the housing 105. , which is more conducive to the relative movement between the rotating piece 107 and the pipe 100; Certainly, those skilled in the art should understand that the above-mentioned bosses can also be arranged on the casing 105 , that is, a semi-circular boss covered with a sheet of friction material can be arranged on the casing 105 .

It should be noted that, in a specific embodiment of the present invention, the stator 105' can be an independent component (not shown in FIG. 1 ), and its surface is in close contact with the surface of the rotating piece 107. In the preferred embodiment of the present invention shown in Figure 1, the separate stator is actually omitted, and the housing 105 replaces the separate stator to realize the function of the stator, which can reduce the parts of the separate stator, thereby making the flow control valve 1 is simpler in structure and lower in cost. For the convenience of description, the function of the housing 105 mentioned in the following description is the same as that of the stator 105'.

The piezoelectric device 12 includes a piezoelectric sheet 106 and a control circuit 104 . In an embodiment of the present invention, the piezoelectric sheet 106 is made of piezoelectric ceramics, such as lead zirconate titanate ceramics. Of course, other piezoelectric materials that can excite the rotating plate to vibrate and drive the rotating plate to rotate can also be used. The control circuit 104 is used to apply a high-frequency voltage to the piezoelectric sheet 106 to excite it to vibrate, thereby generating a driving force.

Referring to Figures 2a-2c, in a preferred embodiment of the present invention, the rotating piece 107 is designed as a shape composed of two opposite fan-shaped parts. Wherein, the piezoelectric sheet 106 is provided in the first fan-shaped part, and the opening 109 is provided in the second fan-shaped part opposite to it. Those skilled in the art should understand that the rotating piece 107 may be completely disc-shaped. Certainly, adopting the above double fan-shaped method can save material, and more importantly, reduce the mass of the rotating piece 107, thereby reducing the inertia of the rotating piece 107, so as to control the position of the rotating piece 107 more accurately.

Similarly, in order to reduce the cost, the friction material sheet 108 can be arranged within the rotation angle range of the rotating sheet 107, instead of being arranged as a whole ring.

In another embodiment of the present invention, the piezoelectric device is disposed on the casing 105 , and correspondingly, a friction material sheet is disposed on the side of the rotating piece 107 in contact with the casing 105 . Of course, similarly, the friction material sheet 108 only needs to be provided within the angle range of rotation of the rotating sheet 107, and a boss can also be provided on the rotating sheet 107 or the housing 105, which will not be repeated here.

The working principle and process of the flow control valve 1 of the present invention will be further described below with reference to the accompanying drawings.

See Figures 2a-2c. The piezoelectric sheet 106 produces an electrostrictive effect after the high-frequency voltage is applied by the control circuit 104, causing the piezoelectric sheet 106 to expand and contract, thereby exciting the rotating sheet 107 to vibrate, and the rotating sheet 108 is made to vibrate by the frictional resistance of the friction material sheet 108. 107 rotates around the shaft 102. Its principle of action is similar to that of piezoelectric motors. In the present invention, the rotating piece 107 is not only the rotor of the piezoelectric drive mechanism, but also a control piece for controlling the flow of the pipeline 100, and meanwhile, the rotating piece 107 is also an elastic piece that generates vibration.

Under the control of the control circuit 104, the flow control valve 1 can rotate the rotating piece 107 to the state where the opening 109 and the pipeline 100 are completely overlapped. At this time, the valve is opened to the maximum, and the fluid flow in the pipeline 100 is the maximum, as shown in Figure 2a It can also be rotated to the state where the opening 109 and the pipeline 100 are partially overlapped. At this time, the valve is in a partially open state, and the fluid flow in the pipeline 100 decreases, as shown in Figure 2b; it can also be rotated to the state where the opening 109 and the pipeline 100 does not overlap, at this time, the valve is closed, the pipeline 100 is cut off, and the fluid flow rate is zero. Through the above method, the opening and closing of the pipeline 100 , and even the size of the fluid flow in the pipeline 100 can be controlled by changing the overlapping area of the opening 109 and the pipeline 100 .

To change the rotation direction of the rotating piece 107, it is only necessary to reverse the phase of the excitation voltage applied to the two poles of the piezoelectric thin piece 106 .

The rotating piece of the flow control valve of the present invention does not need to rotate continuously like a piezoelectric motor, but only needs to rotate reciprocally within a limited angle range, so the friction material piece can only be set within the required range, saving materials, Reduced costs. More importantly, the electrical connection of the piezoelectric thin film does not need to use brushes, so the reliability is high.

In the present invention, the driving mechanism of the flow control valve is designed based on the principle of a piezoelectric motor, instead of merely replacing the driving method of the existing exhaust gas recirculation valve with a piezoelectric motor.

The flow control valve of the present invention is capable of providing sufficient torque without requiring mechanical parts such as a gearbox. It can reduce the weight of the reduction mechanism and the volume it occupies, and can avoid problems such as vibration, impact and noise generated by the gear transmission mechanism. The flow control valve of the present invention has a simpler and more compact structure, can avoid the use of electric brushes, and improves reliability.

The flow control valve of the present invention is driven by traveling wave friction coupling between the rotating plate and the stator. Due to the large holding torque provided by the friction force, the rotating plate of the valve of the present invention can maintain a precise position without consuming extra energy, reducing the overall energy consumption. Compared with the existing methods such as electromagnetic drive and DC motor drive, it is free from magnetic field interference and has lower noise.

The flow control valve of the present invention can be applied in an exhaust gas recirculation system of an internal combustion engine as an exhaust gas recirculation valve to control the flow of exhaust gas recirculation, and has the advantages of high control precision, quietness and low energy consumption.

The above descriptions are only illustrative specific implementations of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the protection scope of the present invention.

Claims (19)

1. A flow control valve, which has a pipeline (100) for fluid to pass through, is characterized in that, a rotating piece (107) that cuts off the pipeline (100) is provided along the vertical direction of the pipeline (100), the The rotating piece (107) is provided with at least one opening (109), and the rotating piece (107) can be rotated to a position where the opening (109) overlaps with the pipe (100), and the opening ( 109) having a diameter no greater than the outer diameter of said pipe (100). 2. The flow control valve according to claim 1, wherein the rotating piece (107) is in sealing contact with the duct wall of the duct (100). 3. The flow control valve according to claim 1, wherein the rotating piece (107) and the pipe (100) are hermetically arranged in a casing (105), and the two ends of the pipe (100) protrude to the outside of the housing (105). 4. The flow control valve according to claim 1, wherein the rotating piece (107) can rotate around the axis of a rotating shaft (102) driven by a driving mechanism (2). 5. The flow control valve according to claim 4, wherein the driving mechanism (2) comprises a stator (105'), at least one piezoelectric device (12) and at least one frictional material sheet (108), the The piezoelectric device (12) is arranged on one of the stator (105') and the rotating piece (107), and the friction material sheet (108) is pressed against the stator through an elastic piece (103). (105') and the rotating piece (107). 6. The flow control valve according to claim 5, wherein the stator (105') is a housing (105) supporting and containing the rotating piece (107) and the pipe (100), the pipe Both ends of (100) protrude outside said housing (105). 7. The flow control valve according to claim 5, wherein the elastic member (103) is arranged around the rotation axis (102) of the rotating piece (107), and moves the rotating piece (107) along the rotation axis ( 102) axially presses against said stator (105'). 8. The flow control valve according to claim 5, wherein, the rotating piece (107) is composed of two opposite fan-shaped parts, the opening (109) is arranged in the first fan-shaped part, and the second fan-shaped part is tightly closed. Press on the friction material sheet (108). 9. The flow control valve according to claim 5, wherein the piezoelectric device (12) comprises a piezoelectric foil (106) and a control circuit (104). 10. The flow control valve according to claim 5, wherein, one of the rotating piece (107) and the stator (105') is provided with a boss, and the boss is connected with the friction material piece (108) connected. 11. The flow control valve according to claim 5, wherein, the friction material sheet (108) is arranged on the stator (105'), and the piezoelectric device (12) is arranged on the rotating sheet ( 107) on. 12. A flow control valve, used for flow control in an exhaust gas recirculation pipeline of an internal combustion engine, the flow control valve (1) has a pipeline (100) communicating with the pipeline, characterized in that, along the pipeline ( 100) A rotating piece (107) that cuts off the pipeline (100) is provided in the vertical direction, and at least one opening (109) is provided on the rotating piece (107), and the rotating piece (107) can be rotated to make Where the opening (109) coincides with the pipe (100), the diameter of the opening (109) is not greater than the outer diameter of the pipe (100). 13. The flow control valve according to claim 12, wherein the rotating piece (107) can rotate around the axis of a rotating shaft (102) driven by a driving mechanism (2), and the driving mechanism (2) Comprising a stator (105'), at least one piezoelectric device (12) and at least one friction material sheet (18), the piezoelectric device (12) is arranged on the stator (105') and the rotating sheet ( 107), the friction material sheet (108) is tightly pressed between the stator (105') and the rotating sheet (107) through an elastic member (103). 14. The flow control valve according to claim 13, wherein the stator (105') is a housing (105) supporting and accommodating the rotating piece (107) and the pipe (100), the pipe Both ends of (100) protrude outside said housing (105). 15. The flow control valve according to claim 13, wherein the elastic member (103) is arranged around the rotation axis (102) of the rotating piece (107), and moves the rotating piece (107) along the rotation axis ( 102) axially presses against said stator (105'). 16. The flow control valve according to claim 13, wherein, the rotating piece (107) is composed of two opposite fan-shaped parts, the opening (109) is set in the first fan-shaped part, and the second fan-shaped part is tightly closed. Press on the friction material sheet (108). 17. The flow control valve of claim 13, wherein the piezoelectric device (12) comprises a piezoelectric foil (106) and a control circuit (104). 18. The flow control valve according to claim 13, wherein, one of the rotating piece (107) and the stator (105') is provided with a boss, and the boss is connected with the friction material piece (108) connected. 19. The flow control valve according to claim 13, wherein the friction material sheet (108) is arranged on the stator (105'), and the piezoelectric device (12) is arranged on the rotating sheet ( 107) on.

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