Disclosure of Invention
In order to solve the problems that the pintle injector in the prior art is difficult to realize the adjustment of micro-opening and is difficult to use in a high-temperature environment, the invention aims to provide a piezoelectric ceramic micro-motion pintle injector adjusting mechanism.
The invention provides the following technical scheme:
a piezoelectric ceramic micro-motion pintle injector adjustment mechanism applied to a pintle injector, the piezoelectric ceramic micro-motion pintle injector adjustment mechanism comprising:
the piezoelectric ceramic assembly comprises a cylindrical shell, wherein an end cap is arranged at one end of the shell along the axis direction, a piezoelectric ceramic stack is arranged in the shell, and the deformation direction of the piezoelectric ceramic stack after voltage is applied to the piezoelectric ceramic stack is the axis direction of the shell;
the mounting bracket is fixedly connected with the shell and is used for being connected with the pintle injector, and the end cap is in sliding fit with the mounting bracket along the axial direction of the shell; and
the adapter is connected with the end cap and used for being connected with a needle valve of the pintle injector.
As a further alternative to the piezo ceramic micro-motion pintle injector adjustment mechanism, the piezo ceramic assembly further comprises a spring urging the end cap against the piezo ceramic stack.
As a further optional scheme for the piezoelectric ceramic micro-motion pintle injector adjusting mechanism, the piezoelectric ceramic component further includes a pre-tightening bolt, the pre-tightening bolt is arranged along an axis direction of the housing, the pre-tightening bolt is in threaded fit with the housing, and the pre-tightening bolt abuts against one end, facing away from the end cap, of the piezoelectric ceramic stack.
As a further optional scheme for the piezoelectric ceramic micro-motion pintle injector adjusting mechanism, the housing is in threaded fit with the mounting bracket, a screwing part is arranged on the housing, and the outer edge of the cross section of the screwing part is not circular.
As a further optional solution for the adjusting mechanism of the piezoelectric ceramic micro-motion pintle injector, a groove is provided at one end of the end cap facing the piezoelectric ceramic stack, a side surface of the groove is a conical surface, and the piezoelectric ceramic stack abuts against the side surface of the groove.
As a further alternative to the piezo ceramic micro-motion pintle injector adjustment mechanism, the adaptor is directly connected to the end cap.
As a further optional scheme for the piezoelectric ceramic micro-motion pintle injector adjusting mechanism, a lever is rotatably arranged on the mounting bracket, the end cap and the adaptor are respectively connected with two ends of the lever, and the end cap is connected with the adaptor through the lever.
As a further alternative to the piezoelectric ceramic micro-motion pintle injector adjustment mechanism, the lever is connected to the mounting bracket by a first flexible hinge, the lever is connected to the end cap by a second flexible hinge, and the lever is connected to the adaptor by a third flexible hinge.
As a further optional scheme for the piezoelectric ceramic micro-motion pintle injector adjusting mechanism, a mounting hole is formed in the mounting bracket, a screw penetrates through the mounting hole, the length of the mounting hole in the axis direction of the lever is greater than the diameter of the screw, and the screw is in threaded fit with the first flexible hinge.
As a further optional scheme for the piezoelectric ceramic micro-motion pintle injector adjusting mechanism, a protective shell is arranged on the mounting bracket, and the lever is located inside the protective shell.
The embodiment of the invention has the following beneficial effects:
after voltage is applied to the piezoelectric ceramic stack, the piezoelectric ceramic stack deforms along the axis direction of the shell, and the deformation amplitude of the piezoelectric ceramic stack changes along with the change of the voltage. The piezoelectric ceramic stack extrudes the end cap in the deformation process, so that the end cap slides along the axis direction of the shell, and the end cap drives the needle valve of the pintle injector to move through the adapter piece, thereby realizing the adjustment of the pintle injector.
On one hand, the piezoelectric ceramic stack can keep the response time of a sub-millisecond level and the opening degree of a micron level, so that the micro-adjustment of the pintle injector can be realized. On the other hand, the piezoelectric ceramic stack is used as a driving source, the deformation characteristic of the material of the piezoelectric ceramic stack is utilized, the complexity of the whole structure is reduced, the reliability is improved, and meanwhile, the use of electronic components is reduced, so that the piezoelectric ceramic stack can normally operate in severe environments such as high temperature.
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible and comprehensible, preferred embodiments accompanied with figures are described in detail below.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the templates herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Example 1
Referring to fig. 1 to 8, the present embodiment provides a piezoelectric ceramic micro-motion pintle injector adjusting mechanism (hereinafter, referred to as "adjusting mechanism") for adjusting the pintle injector 500 to control the propellant injection state, and finally realize the variable thrust of the rocket engine. The adjusting mechanism comprises a piezoelectric ceramic component 100, a mounting bracket 200 and an adapter 300, wherein the piezoelectric ceramic component 100 outputs power, the piezoelectric ceramic component 100 is connected with a pintle injector 500 through the mounting bracket 200, and the adapter 300 transmits the power output by the piezoelectric ceramic component 100 to a needle valve of the pintle injector 500.
Specifically, piezo ceramic assembly 100 includes a housing 110, a piezo ceramic stack 120, and end caps 130.
The housing 110 is cylindrical, one end of which is closed and the other end of which is open.
The piezo stack 120 is disposed in the housing 110, and is composed of a plurality of piezo sheets, and each piezo sheet is arranged along the axial direction of the housing 110. After applying voltage to the piezoelectric ceramic plates, each piezoelectric ceramic plate deforms along the axial direction of the casing 110, that is, the entire piezoelectric ceramic stack 120 deforms along the axial direction of the casing 110.
Furthermore, one end of housing 110 is closed, and piezo ceramic stack 120 can only be deformed toward the open end of housing 110, limited by the internal walls or other structure of housing 110.
End cap 130 is disposed at the open end of housing 110, opposite to the end of piezo-ceramic stack 120 along the axis of housing 110. When piezoceramic stack 120 expands and deforms, end cap 130 is pushed to move along the axial direction of housing 110.
Further, the end cap 130 has a groove 131 at an end facing the piezo ceramic stack 120, and the side of the groove 131 is a tapered surface and abuts against the end of the piezo ceramic stack 120. Accordingly, the end of the piezo ceramic stack 120 facing the end cap 130 is configured as a hemisphere.
After the hemispherical end of the piezoelectric ceramic stack 120 is inserted into the groove 131, the groove 131 restricts the end of the piezoelectric ceramic stack 120, and the deformation of the piezoelectric ceramic stack 120 is concentrated in the axial direction of the housing 110, thereby ensuring the adjustment accuracy.
In this embodiment, the groove 131 is conical.
Further, when piezoceramic stack 120 contracts and deforms, a lost motion is likely to occur between end cap 130 and piezoceramic stack 120, so that when piezoceramic stack 120 expands again, end cap 130 cannot be immediately acted on. To solve this problem, the piezoceramic assembly 100 further comprises a spring 140.
Spring 140 applies a spring force to end cap 130 along the axis of housing 110 and the spring force is directed toward piezoceramic stack 120, causing end cap 130 to move with the end of piezoceramic stack 120 and remain in close proximity to piezoceramic stack 120.
Further, a preload nut 112 is fixed to the closed end of the housing 110 by welding or integral molding, and the axis of the preload nut 112 coincides with the axis of the housing 110. The pre-tightening nut 112 is provided with a pre-tightening bolt 150 which is in threaded fit with the pre-tightening nut. In addition, the closed end of the casing 110 is further provided with a circular hole, and the pre-tightening bolt 150 can freely pass through the circular hole and abut against one end of the piezoelectric ceramic stack 120 facing away from the end cap 130.
The pretension bolt 150 is in threaded fit with the housing 110 through the pretension nut 112, and the relative position of the pretension bolt 150 and the housing 110 in the axial direction can be changed by screwing the pretension bolt 150, so that the initial position of the piezoelectric ceramic stack 120 is changed. The upper and lower limits of the adjustment range are changed synchronously with the maximum deformation of the piezo-ceramic stack 120 unchanged.
Specifically, the mounting bracket 200 is composed of a bracket body 210 and a flange 220. The holder body 210 has a cylindrical shape, and both the axis of the holder body 210 and the axis of the flange 220 coincide with the axis of the housing 110.
The end of the bracket body 210 facing the outer shell 110 is provided with an internal thread, correspondingly, the end of the outer shell 110 facing the bracket body 210 is provided with an external thread, and the outer shell 110 and the bracket body 210 are fixed in a threaded connection manner.
Furthermore, the outer shell 110 is provided with a screwing part 111, and the outer edge of the cross section of the screwing part 111 is in a regular hexagon shape, so that the screwing part can be conveniently matched with tools such as a wrench, and the screwing part is not easy to slip off in the process of screwing the outer shell 110. Similarly, the end of the bracket body 210 facing the outer shell 110 is also provided in a hexagonal nut shape.
The end cap 130 is located in the holder body 210 and slidably engages with the holder body 210 in the axial direction of the housing 110. When the piezo ceramic stack 120 pushes on the end cap 130, the holder body 210 positions and guides the end cap 130.
The middle part of the inner wall of the bracket body 210 protrudes inwards to form a ring-shaped bump 211. End cap 130 is comprised of a large end 132 and a small end 133, with large end 132 abutting piezoceramic stack 120 and small end 133 passing freely through the middle of bump 211. The spring 140 is a disc spring, and the spring 140 is sleeved on the small end 133 of the end cap 130. The spring 140 is supported by the protrusion 211 to apply an elastic force to the cap 130 by abutting one side of the spring against the large end 132 of the cap 130 and abutting the other side of the spring against the protrusion 211.
Through holes 212 are formed in pairs at one end of the side wall of the holder body 210, which faces away from the housing 110, so that the needle valve of the pintle injector 500 can pass through the through holes and can move along the axial direction of the holder body 210.
The end of the holder body 210 facing away from the housing 110 is integrally formed with or welded to the flange 220, and the flange 220 is bolted to the head of the pintle injector 500.
Specifically, the adaptor 300 is located on a side of the protrusion 211 opposite to the large end 132, and the adaptor 300 is provided with an internal thread to be screwed with the small end 133. One end of the adaptor 300, which faces away from the protrusion 211, is provided with a threaded hole 310, and the threaded hole 310 is arranged along the radial line direction of the holder body 210 and is in threaded fit with a needle valve of the pintle injector 500.
In operation, a voltage is applied to piezo stack 120, causing piezo stack 120 to deform along the axis of housing 110. During the deformation process, the piezo-ceramic stack 120 presses the end cap 130, so that the end cap 130 slides along the axial direction of the housing 110. The end cap 130 drives the needle valve of the pintle injector 500 to move through the adaptor 300, so as to adjust the opening of the pintle injector 500.
In the above process, the deformation amplitude of the piezoelectric ceramic stack 120 changes with the change of the voltage, and the deformation amount of the piezoelectric ceramic stack 120 can be controlled by controlling the voltage signal. For example, when a high voltage is applied to piezo stack 120, the amount of deformation of piezo stack 120 is greater, and the amount of displacement of end cap 130 is also greater; when a low voltage is applied to piezo stack 120, the amount of deformation of piezo stack 120 is smaller and the amount of displacement of end cap 130 is also smaller.
Taking the piezo-ceramic stack 120 with a length of 100mm as an example, a fine adjustment of 0-100 μm can be achieved for the opening of the pintle injector 500.
In one aspect, the piezo-ceramic stack 120 may maintain sub-millisecond response times and micron-scale opening adjustments to enable fine-tuning of the pintle injector 500. On the other hand, the piezoelectric ceramic stack 120 is used as a driving source, and the deformation characteristic of the material of the piezoelectric ceramic stack 120 is utilized, so that the complexity of the whole structure is reduced, the reliability is improved, and meanwhile, the use of electronic components is reduced, and the piezoelectric ceramic stack can normally operate in severe environments such as high temperature.
The adjustment mechanism is a direct drive adjustment mechanism and is suitable for a pintle injector 500 with a small adjustment range. A direct drive adjustment mechanism may be employed when the amount of deformation of the piezo ceramic stack 120 may cover the adjustment range of the pintle injector 500, or when the radial dimension of the entire pintle injector 500 system is limited. In addition, compared with the existing adjusting structure, the direct-drive adjusting mechanism simplifies the transmission parts and has a simpler structure, thereby improving the reliability of the pintle injector 500 system.
Example 2
Referring to fig. 9 to 14, the difference from embodiment 1 is that the end cap 130 is not directly connected to the adaptor 300.
Specifically, the mounting bracket 200 has a plate shape and is perpendicular to the axis of the housing 110. The heads of the piezo-ceramic assembly 100 and the pintle injector 500 are connected to both ends of the mounting bracket 200 in the length direction, respectively, and the heads of the piezo-ceramic assembly 100 and the pintle injector 500 are located at the same side of the mounting bracket 200.
Through the arrangement of the integrated mounting bracket 200, the housing 110 and the head of the pintle injector 500 can be tightly matched with each other, and the adjustment error caused by assembly is avoided.
The side of the mounting bracket 200 facing away from the housing 110 is provided with a first flexible hinge 410, a second flexible hinge 420 and a third flexible hinge 430, the second flexible hinge 420, the first flexible hinge 410 and the third flexible hinge 430 are arranged along the length direction of the mounting bracket 200, the second flexible hinge 420 is opposite to the piezoelectric ceramic assembly 100, and the third flexible hinge 430 is opposite to the head of the pintle injector 500.
The mounting bracket 200 is provided with mounting holes in pairs, the mounting holes are arranged along the thickness direction of the mounting bracket 200, and the two mounting holes are arranged along the width direction of the mounting bracket 200. The two mounting holes are respectively provided with a screw 230, and the screw 230 passes through the mounting hole and then is in threaded connection with the first flexible hinge 410. Tightening the screw 230 frictionally secures the first flexible hinge 410 to the mounting bracket 200.
The side of the first flexible hinge 410 facing away from the mounting bracket 200 is fixedly connected with the lever 400 by welding, bolting, gluing, etc., and the lever 400 is rotatably disposed on the mounting bracket 200 with the first flexible hinge 410 as a fulcrum.
The small end 133 of the end cap 130 is threaded through the middle of the protrusion 211 and is connected to the second flexible hinge 420, and the side of the second flexible hinge 420 opposite to the end cap 130 is fixedly connected to one end of the lever 400 by welding or the like.
The adaptor 300 is provided with an external thread and a threaded hole 310, and is in threaded connection with the third flexible hinge 430 through the external thread, and one side of the third flexible hinge 430, which is away from the adaptor 300, is fixedly connected to one end of the lever 400, which is away from the first flexible hinge 410, through welding and other manners.
At this time, after the piezo ceramic stack 120 pushes the end cap 130 to move along the axial direction of the housing 110, the end cap 130 pries the adaptor 300 through the lever 400, so as to drive the needle valve of the pintle injector 500 to move, and the moving distance of the needle valve is in a certain proportion to the moving distance of the end cap 130.
In this embodiment, the distance between the first flexible hinge 410 and the second flexible hinge 420 is less than the distance between the first flexible hinge 410 and the third flexible hinge 430, so the needle valve moves a distance greater than the end cap 130. The lever 400 amplifies the displacement of the end cap 130 while transmitting the driving force between the end cap 130 and the needle valve, thereby allowing the adjustment range of the pintle injector 500 to be greater than the maximum amount of deformation of the piezo ceramic stack 120.
Further, the length of the mounting hole along the length direction of the mounting bracket 200 is greater than the diameter of the screw 230. After the screw 230 is loosened, the position of the first flexible hinge 410 is adjusted along the length direction of the mounting bracket 200, and then the screw 230 is screwed, so that the position of the fulcrum of the lever 400 can be changed, the relative length of the force arms at the two sides of the fulcrum is further changed, and finally the scaling of the displacement of the lever 400 to the end cap 130 is changed.
In particular, when the first flexible hinge 410 is located at the midpoint of the connection line between the second flexible hinge 420 and the third flexible hinge 430, the lever 400 scales the displacement of the end cap 130 by 1, and the lever 400 only plays a role in transmitting and changing the direction of the driving force.
Further, the protective shell 240 is fixed to one side of the passive piezoelectric ceramic assembly 100 of the mounting bracket 200 by welding or bolting, and the lever 400, the first flexible hinge 410, the second flexible hinge 420 and the third flexible hinge 430 are all located inside the protective shell 240, and operate stably under the protection of the protective shell 240.
The adjustment mechanism is a flexible hinge type adjustment mechanism and is suitable for the pintle injector 500 with a large adjustment range. Flexible hinged adjustment mechanisms may be used when the amount of deformation of the piezo ceramic stack 120 does not cover the adjustment range of the pintle injector 500, or when the axial dimension of the entire pintle injector 500 system is limited.
The flexible hinge type adjusting mechanism can cover a larger adjusting range, and meanwhile, the response time of the piezoelectric ceramic stack in a 120 mm scale and the opening adjustment in a micron scale are maintained. By changing the position of the first flexible hinge 410, various scaling can be achieved to accommodate various adjustment requirements.
In another embodiment of the present application, the end cap 130 may also be connected to the adaptor 300 by a two-stage or more flexible hinge structure to achieve sufficient magnification.
In all examples shown and described herein, any particular value should be construed as merely exemplary, and not as a limitation, and thus other examples of example embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
The above examples are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.