An auxiliary device for suppressing vibration during machining of outer frame of inertial platform

Abstract

The present invention provides an auxiliary device for suppressing the machining chatter of the outer frame of an inertial platform, which belongs to the field of mechanical machining technology, and includes a damping component and a supporting component, wherein the supporting component is installed on the outer side of the damping component, and the damping component includes a damping box, a damping ball is arranged inside the damping box, and the damping ball is connected to the inner wall of the damping box through a damping spring, and the bottom of the damping ball is connected to a plumb line, and the bottom of the plumb line is connected to a pendant, and the supporting component is symmetrically installed on both sides of the damping box, and each side of the supporting component includes a mounting block, and the mounting block is fixed at the center of the outer wall of the damping box, and the mounting block is provided with an outwardly inclined mounting rod at intervals, and a telescopic rotating rod is arranged at the end of the mounting rod, and a universal mechanism is arranged at one end of the telescopic rotating rod away from the mounting rod. The present invention can effectively enhance the rigidity of the thin-walled outer frame of the inertial platform, and utilize the damping component to consume the vibration power flow of the parts to achieve the purpose of suppressing the machining chatter of the thin-walled parts.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and in particular relates to an auxiliary device for suppressing machining vibration of an outer frame of an inertial platform. Background Art

[0002] The inertial platform is a device that uses a gyroscope to keep the platform unchanged in the inertial space, also known as a gyroscope stabilized platform. It is an important component in the inertial navigation system. The inertial platform consists of a platform, three single-axis gyroscopes, an inner frame, an outer frame, a torque motor, an angle sensor, and a servo electronic circuit. The platform is supported on a base through an inner frame and an outer frame, and the base is fixedly connected to the aircraft.

[0003] The outer frame of the inertial platform is a thin-walled cast titanium alloy frame part with a low thickness-to-diameter ratio of 0.025 (wall thickness 14.5mm / diameter 580mm). Due to its weak rigidity, it is very easy to produce vibration during processing, which seriously restricts the processing accuracy of the part and results in low processing efficiency of the part.

[0004] The problems that arise during the processing of the low aspect ratio inertial platform outer frame are as follows:

[0005] (1) Thin-walled parts have poor rigidity and are easily deformed during processing.

[0006] The existing solution is to reduce cutting force and machining deformation by changing cutting parameters (mostly reducing cutting depth and rotation speed). However, reducing cutting parameters may lead to low cutting efficiency, rapid tool wear, poor surface integrity and other results.

[0007] (2) Due to the structural characteristics of thin-walled parts cutting, most of the chatter is regenerative chatter. Its main mechanism is that during the cutting process, under the action of the dynamic cutting force generated by the interaction between the tool and the thin-walled part, the cutting system produces vibration displacement. The phase difference between the two cutting vibration displacements causes the change in cutting thickness, which in turn causes the dynamic change of cutting force. The change in chip thickness causes the fluctuation of cutting force, which in turn stimulates the relative vibration of the tool and the thin-walled part, causing the system to vibrate and leave chatter marks again. If the cycle is repeated, it is possible that the initial small chatter marks will spread to the entire processing surface, forming regenerative chatter.

[0008] The existing solutions are: for milling and boring of thin-walled plate parts with simple structures, most of them control cutting parameters and use cutting stability lobe diagrams to optimize cutting parameters to avoid chatter. However, external frame parts are cavity parts, and special-shaped structures, reinforcing ribs, circular holes and other structures greatly hinder the dynamic modeling of the external frame. In addition, the processing and clamping process of the external frame makes the boundary conditions of the external frame very complex. There are many constraints that cannot be ignored in solving the control equations of the cutting system.

[0009] Therefore, it is very necessary to invent a device that can solve the machining vibration of the outer frame of the inertial platform. Summary of the invention

[0010] The problem to be solved by the present invention is to provide an auxiliary device for suppressing machining vibration of an outer frame of an inertial platform.

[0011] In order to solve the above technical problems, the technical solution adopted by the present invention is: an auxiliary device for suppressing the machining flutter of the outer frame of an inertial platform, comprising a damping component and a supporting component, wherein the supporting component is installed on the outside of the damping component, the damping component comprises a damping box, a damping ball is arranged inside the damping box, the damping ball is connected to the inner wall of the damping box through a damping spring, the bottom of the damping ball is connected to a plumb line, the bottom of the plumb line is connected to a pendant, the supporting component is symmetrically installed on both sides of the damping box, each side of the supporting component comprises a mounting block, the mounting block is fixed at the center position of the outer side wall of the damping box, a plurality of mounting rods inclined outward are arranged at intervals on the mounting block, a telescopic rotating rod is arranged at the end of the mounting rod, and a universal mechanism is arranged at one end of the telescopic rotating rod away from the mounting rod.

[0012] Furthermore, the damping box is a square frame.

[0013] Furthermore, four damping springs are provided, and the four damping springs are evenly distributed around the damping ball. One end of the four damping springs is fixed to the damping ball, and the other end is respectively fixed to four inner walls of the damping box.

[0014] Furthermore, the elastic coefficients and stretching amounts of the four damping springs are consistent.

[0015] Furthermore, the pendant is a conical pendant, and when pulled by the plumb line, the pendant can swing under force.

[0016] Furthermore, the universal mechanism includes a ball head rod, one end of which is connected to the telescopic rotating rod, and the other end is provided with a ball head, which is installed in the ball bowl of the ball seat, and the ball pressure cover is buckled on the ball seat, so that the ball head at the end of the ball head rod can rotate in the ball seat to achieve a universal connection.

[0017] Furthermore, the threads on both sides of the telescopic rotary rod are reverse threads, and when the telescopic rotary rod is rotated, the ball head rod and the mounting rod are telescoped at the same time.

[0018] Furthermore, a pressure sensor is provided on the ball seat, and the pressure sensor is used to measure the supporting force between the ball seat and the outer frame.

[0019] Furthermore, a rubber pad is provided at the bottom of the ball seat, and the rubber pad is located between the ball seat and the outer frame.

[0020] Furthermore, when the supporting component of the present invention is used to support the inner cavity of the outer frame, the pressures of the various pressure sensors should be adjusted to be consistent, thereby achieving equal-rigidity support.

[0021] Furthermore, the damping component and the supporting component are installed in the outer frame. During cutting, the damping component and the supporting component form a cutting system with the outer frame. The control equation of the cutting system is:

[0022]

[0023] in, m n For the outer frame n Modal mass of a point ；c n For the outer frame n Modal damping of a point; c’ n+1 is the modal damping of the boundary connecting the nth point of the outer frame and the damping component (solved using the penalty parameter method); k n For the outer frame n Modal stiffness of a point; k’ n+1 is the modal stiffness of the boundary connecting the nth point of the outer frame and the damping component (solved using the penalty parameter method); m zn The damping component is set in the outer frame. n Modal mass of a point; c zn The damping component is set in the outer frame. n Modal damping of a point; k zn The damping component is set in the outer frame. n Modal stiffness of a point; For the n The acceleration of a point; For the n The speed of the point; For the n Displacement of a point; is the cutting force; n =1,2,3......, i for n Any point in ; t For time.

[0024] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0025] (1) The supporting component of the present invention has a simple and compact structure. The supporting component is used to improve the rigidity of the outer frame. At the same time, the supporting component is detected by a pressure sensor to ensure that the support is of equal rigidity and avoid thin-wall deformation.

[0026] (2) The support component of the present invention includes a mounting rod that is tilted outward, which has high support strength and increases the end support range, thereby avoiding deformation of thin walls due to concentrated support during cutting. In addition, the mounting rod contacts the inner wall of the outer frame at multiple points with small areas, which is more suitable for the structure of the outer frame with special shapes and holes.

[0027] (3) The damping component of the present invention contains a damping spring and a damping ball. The damping amount varies according to the stretching or compression of the spring by the movement of the damping ball. Also, because the damping component is connected to the outer frame through the supporting component, which is a rigid connection, the addition of the supporting component and the damping component changes the modal mass, modal damping and modal stiffness of the original cutting system, breaking the original regenerative flutter energy balance.

[0028] (4) The vibration generated during the processing of the present invention will be directly transmitted to the damping box, and the damping box consumes the vibration energy through the continuous damping movement of the damping ball, thereby playing a role in suppressing the vibration.

[0029] It can be seen that the present invention can effectively enhance the rigidity of thin-walled parts, and utilize the damping component to consume the vibration power flow of the parts, thereby achieving the purpose of suppressing the machining chatter of thin-walled parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention in any sense. In the accompanying drawings:

[0031] Figure 1 It is a structural diagram of the outer frame in the prior art.

[0032] Figure 2 It is a structural schematic diagram of the present invention.

[0033] Figure 3 It is a schematic diagram of the use state of the present invention.

[0034] Figure 4 It is a structural schematic diagram of the universal mechanism of the present invention.

[0035] Figure 5 It is a schematic structural diagram of the supporting component of the present invention.

[0036] Figure 6 It is a schematic structural diagram of the damping component of the present invention.

[0037] Figure 7It is a partial schematic diagram of the damping component of the present invention.

[0038] In the figure:

[0039] 1. Pendant; 2. Plumb rope; 3. Damping spring; 4. Damping box; 5. Damping ball; 6. Mounting block; 7. Mounting rod; 8. Telescopic swivel rod; 9. Ball head rod; 10. Ball pressure cover; 11. Ball seat; 12. Rubber pad; 13. Ball head; 14. Outer frame. DETAILED DESCRIPTION

[0040] like Figures 1 to 7 As shown, the auxiliary device for suppressing machining vibration of an outer frame of an inertial platform of the present invention comprises a damping component and a supporting component, wherein the supporting component is installed outside the damping component.

[0041] The damping component includes a damping box 4, which is a square frame. A damping ball 5 is arranged inside the damping box 4. The damping ball 5 is connected to the inner wall of the damping box 4 through a damping spring 3. Four damping springs 3 are arranged, and the four damping springs 3 are evenly distributed around the damping ball 5. One end of the four damping springs 3 is fixed to the damping ball 5, and the other end is respectively fixed to the four inner walls of the damping box 4.

[0042] Among them, the elastic coefficients and stretching amounts of the four damping springs 3 are consistent.

[0043] The bottom of the damping ball 5 is connected with a plumb line 2, and the bottom of the plumb line 2 is connected with a pendant 1. The pendant 1 is a conical pendant. When the plumb line 2 is pulled, the pendant 1 can swing under force.

[0044] The supporting components are symmetrically installed on both sides of the damping box 4, and each side of the supporting components includes a mounting block 6, which is fixed to the center position of the outer wall of the damping box 4. Three mounting rods 7 inclined outward are arranged at intervals on the mounting block 6. A telescopic rotating rod 8 is arranged at the end of the mounting rod 7. A ball head rod 9 is arranged at the end of the telescopic rotating rod 8 away from the mounting rod 7. A ball head 13 is arranged at the end of the ball head rod 9. The ball head 13 is installed in the ball bowl of the ball seat 11. The ball pressure cover 10 is buckled on the ball seat 11 so that the ball head 13 at the end of the ball head rod 9 can rotate in the ball seat 11 to realize a universal connection.

[0045] The threads on both sides of the telescopic rotary rod 8 are reverse threads. When the telescopic rotary rod 8 is rotated, the ball head rod 9 and the mounting rod 7 are telescoped at the same time.

[0046] The ball seat 11 is provided with a pressure sensor, and the pressure sensor is used to measure the supporting force between the ball seat 11 and the outer frame 14 .

[0047] A rubber pad 12 is disposed at the bottom of the ball seat 11 , and the rubber pad 12 is located between the ball seat 11 and the outer frame 14 .

[0048] When the present invention is used to support the inner cavity of the outer frame 14, the pressures of the six pressure sensors should be adjusted to be consistent, thereby achieving equal rigidity support.

[0049] When the outer frame 14 is used as a thin-walled part for cutting, the control equation of the cutting system formed by the outer frame 14 is:

[0050]

[0051] in, is the mass matrix of the cutting system; is the damping matrix of the cutting system; is the stiffness matrix of the cutting system; is the cutting force vector; , , It is an inherent property of the cutting system; Related to cutting parameters and tool parameters; is the acceleration vector; is the velocity vector; is the displacement vector, where x is a function of t.

[0052] Based on the position-dependent characteristics of thin-walled part cutting, the unit model in the external frame 14 cutting system is discretized, and the cutting system is understood as n The mass-spring-damper system with 1 degree of freedom. At this time, the control equation of the cutting system can be expanded as follows:

[0053]

[0054] in, m n 、c n 、k n is the modal mass, modal damping, and modal stiffness of each point on the discrete rear outer frame 14 ( n =1, 2, 3...; i for n any point in ); is the acceleration of the nth point; is the speed of the nth point; is the displacement of the nth point; is the cutting force, machining process, For time t function.

[0055] The present invention changes the parameters of the modal mass, modal damping and modal stiffness of the original cutting system by arranging the damping component and the supporting component in the outer frame 14. At this time, the control equation of the cutting system is:

[0056]

[0057] in, m zn 、c zn 、k zn is the modal mass, modal damping and modal stiffness of each point of the damping component arranged in the outer frame 14 ( n =1,2,3...); c’ n+1 is the modal damping of the connection boundary between the nth point of the outer frame 14 and the damping component (solved by the penalty parameter method through the material properties and size parameters of the outer frame); k’ n+1 is the modal stiffness of the boundary connecting the nth point of the outer frame and the damping component (solved by the penalty parameter method through the material properties and size parameters of the outer frame).

[0058] It can be seen that when the cutting parameters and the material of the outer frame 14 do not change, the cutting force vector generated during processing When the modal mass, modal damping and modal stiffness become larger, the cutting system becomes more stable and the thin-walled plate is less likely to vibrate due to various reasons.

[0059] When in use, the parameters of the damping component and the supporting component can be adjusted according to the relationship between the various parameters of the cutting system.

[0060] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An auxiliary device for suppressing the machining vibration of the outer frame of an inertial platform, characterized in that: The invention comprises a damping component and a supporting component, wherein the supporting component is installed on the outside of the damping component, the damping component comprises a damping box, a damping ball is arranged inside the damping box, the damping ball is connected to the inner wall of the damping box through a damping spring, a plumb line is connected to the bottom of the damping ball, a pendant is connected to the bottom of the plumb line, the supporting component is symmetrically installed on both sides of the damping box, each supporting component comprises a mounting block, the mounting block is fixed at the center of the outer wall of the damping box, a plurality of mounting rods inclined outward are arranged at intervals on the mounting block, a telescopic rotating rod is arranged at the end of the mounting rod, and a universal mechanism is arranged at one end of the telescopic rotating rod away from the mounting rod; The damping box is a square frame; four damping springs are arranged, and the four damping springs are evenly distributed around the damping ball, one end of the four damping springs is fixed to the damping ball, and the other end is respectively fixed to the four inner walls of the damping box; the elastic coefficients and stretching amounts of the four damping springs are consistent; the universal mechanism includes a ball head rod, one end of the ball head rod is connected to the telescopic rotary rod, and the other end is provided with a ball head, the ball head is installed in the ball bowl of the ball seat, and the ball pressure cover is buckled on the ball seat so that the ball head at the end of the ball head rod rotates in the ball seat to achieve a universal connection; the threads on both sides of the telescopic rotary rod are reverse threads, and when the telescopic rotary rod is rotated, the ball head rod and the mounting rod are extended and retracted at the same time; a pressure sensor is arranged on the ball seat, and the pressure sensor is used to measure the supporting force between the ball seat and the outer frame; a rubber pad is arranged at the bottom of the ball seat, and the rubber pad is located between the ball seat and the outer frame; when the supporting component is used to support the inner cavity of the outer frame, the pressure of each pressure sensor is adjusted to be consistent to achieve equal stiffness support; The damping component and the supporting component are installed in the outer frame. During cutting, the damping component, the supporting component and the outer frame form a cutting system. The control equation of the cutting system is: in, m n For the outer frame n Modal mass of a point ；c n For the outer frame n Modal damping of a point; c’ n+1 is the modal damping of the boundary connecting the nth point of the outer frame and the damping component; k n For the outer frame n Modal stiffness of a point; k’ n+1 is the modal stiffness of the boundary connecting the nth point of the outer frame and the damping component; m zn The damping component is set in the outer frame. n Modal mass of a point; c zn The damping component is set in the outer frame. n Modal damping of a point; k zn The damping component is set in the outer frame. n Modal stiffness of a point; For the n The acceleration of a point; For the n The speed of the point; For the n Displacement of a point; is the cutting force; n =1,2,3......, i for n Any point in ; t For time.

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