阅读说明：本技术 一种静压力可控的超声表面滚压方法和装置 (Static pressure controllable ultrasonic surface rolling method and device ) 是由 王帅 付秀丽 周彬 于 2019-10-21 设计创作，主要内容包括：本发明涉及一种静压力可控的超声表面滚压方法和装置,所述方法根据两点确定一条直线、两条相交直线确定一个平面的原理,通过红外位移传感器检测,利用线性拟合和求均值的方法,实现对待加工工件表面水平度的测定,以实现对静压力的规划。所述装置通过控制电磁铁中通入电流大小调节其与永磁铁间的磁力,进而调控静压力的大小。电磁铁和永磁铁组成的系统属于柔性系统,当加工面平面度变化较小时,静压力可自动维持稳定。另外,滚压头和滚压头安装壳采用同极永磁铁,可使得滚压头位置保持相对稳定,并在减小其间摩擦的同时增加散热。本发明具有结构简单、反应速度快、对加工面水平度要求较低、加工质量较高的优点。(The invention relates to an ultrasonic surface rolling method and device with controllable static pressure, wherein the method realizes the measurement of the levelness of the surface of a workpiece to be processed by using a method of linear fitting and averaging through the detection of an infrared displacement sensor according to the principle that one straight line is determined at two points and the two intersected straight lines determine one plane, so as to plan the static pressure. The device adjusts the magnetic force between the electromagnet and the permanent magnet by controlling the current passing through the electromagnet, so as to adjust and control the static pressure. The system composed of the electromagnet and the permanent magnet belongs to a flexible system, and when the flatness of the machined surface changes slightly, the static pressure can be automatically maintained to be stable. In addition, the rolling head and the rolling head mounting shell adopt homopolar permanent magnets, so that the position of the rolling head can be kept relatively stable, and the friction between the rolling head and the rolling head mounting shell is reduced while the heat dissipation is increased. The invention has the advantages of simple structure, high reaction speed, low requirement on the levelness of a processing surface and high processing quality.)

1. An ultrasonic surface rolling method and device with controllable static pressure are characterized in that: the device comprises an electromagnet, a permanent magnet, a baffle, a pressure sensor, an ultrasonic transducer, an amplitude transformer, a rolling head, an outer sleeve rear cover, an outer sleeve, an amplitude transformer guide sleeve, a rolling head mounting shell, a sensor retainer, a fastening screw, an infrared displacement sensor and a control system, wherein the electromagnet is fixed on the outer sleeve rear cover; the outer sleeve, the outer sleeve rear cover, the electromagnet, the amplitude transformer guide sleeve and the rolling head mounting shell are in a fixed state, and the rest are in a synchronous floating state; the infrared displacement sensor is fixed on the sensor holder, and the sensor holder is fixed on the outer sleeve through a fastening screw.

2. The ultrasonic surface rolling method and device with controllable static pressure as claimed in claim 1, wherein: the magnetic force between the electromagnet and the permanent magnet provides static pressure and maintains the stability of the static pressure.

3. The ultrasonic surface rolling method and device with controllable static pressure as claimed in claim 1, wherein: the infrared displacement sensors are fixed on the sensor holder, the positions of the infrared displacement sensors can be adjusted according to the size of a workpiece, the two sensors are enabled to simultaneously move to cover the whole workpiece plane along the X-axis or Y-axis direction of the machine tool or any one of the sensors is enabled to respectively move to cover the whole workpiece plane along the X-axis and Y-axis directions of the machine tool according to actual conditions before formal machining, the control system uniformly records parameters of each point on a moving track according to a preset program, linear fitting is respectively carried out in the X-axis and Y-axis directions of the machine tool, the levelness of the workpiece is obtained through analysis, and the change range of static pressure is planned.

4. The ultrasonic surface rolling method and device with controllable static pressure as claimed in claim 1, wherein: when the two sensors are installed, the two sensors are symmetrically arranged along the symmetrical axis of the sensor holder, and scales capable of displaying the linear distance between the two sensors are marked on the sensor holder according to angles.

5. The ultrasonic surface rolling method and device with controllable static pressure as claimed in claim 1, wherein: the rolling head and the rolling head mounting shell adopt homopolar permanent magnets, the rolling head is always positioned in the center of an inner hole of the rolling head mounting shell, and heat dissipation can be increased while friction between the rolling head and a rolling head shell is reduced.

Technical Field

The invention relates to the field of metal surface strengthening, in particular to an ultrasonic surface rolling method and device with controllable static pressure.

Background

As one of the surface strengthening technologies, ultrasonic surface rolling can effectively improve the flatness of the surface of a material, enhance the surface microhardness of the material, generate residual compressive stress, and simultaneously change the microstructure of the surface layer of the material, thereby effectively improving the wear resistance and the fatigue resistance of the material. In the ultrasonic rolling process, the static pressure is an important factor influencing the surface processing precision, and a good surface strengthening effect can be obtained by proper static pressure. The material has different surface planeness due to inevitable bulges or pits in pretreatment processing, the currently used ultrasonic rolling device cannot well respond to the change of static pressure and maintain the stability of the static pressure, when the bulges exist on the surface of the material, the static pressure can be increased, and further the mechanical vibration of a rolling head is inhibited, so that the friction force between the rolling head and the material is increased, and the surface of the material is easy to drop or scratch; when the material is provided with the pits, the static pressure is reduced, the plastic deformation is difficult to generate on the surface of the material or the depth of the plastic deformation is low, and the surface performance of the material is difficult to effectively improve. Meanwhile, small deviation always exists in the operation process, and the static pressure changes correspondingly when the surface to be processed is placed and inclined. Nowadays, high-tech technologies such as aerospace and the like are rapidly developed, requirements for mechanical parts are higher and higher, surface quality of key parts is improved through ultrasonic surface rolling, and the method has important significance for increasing safe operation time of the key parts. Therefore, the adjustment of the static pressure and the stabilization of the static pressure have important significance in the ultrasonic rolling system.

In addition, the rolling head is in a high-speed vibration state, friction exists inevitably between the rolling head and the rolling head mounting shell, abrasion is caused to the friction surface of the rolling head, a large amount of friction heat is generated, and the service life of the rolling head and the rolling head mounting shell is seriously influenced. In order to keep the rolling uniformity, the positions of the rolling head and the rolling head mounting shell are relatively fixed. In general, if the gap between the rolling head and the rolling head mounting shell is large, the heat dissipation is good, but the relative position between the rolling head and the rolling head mounting shell is easy to change when the machined surface is not flat, and if the gap between the rolling head and the rolling head mounting shell is small, the relative position between the rolling head and the rolling head mounting shell is fixed, but the heat dissipation is poor and the friction is severe. The rolling head and the rolling head mounting shell adopt homopolar permanent magnets, so that the position of the rolling head relative to the rolling head mounting shell can be kept fixed while the gap between the rolling head and the rolling head mounting shell is increased to increase heat dissipation, friction can be avoided, the service life of the rolling head and the rolling head mounting shell is greatly prolonged, and the quality of ultrasonic rolling parts is greatly improved. Therefore, it is also of great importance to reduce wear on the stitching heads, to increase heat dissipation, while keeping the relative positions of the stitching heads stable in an ultrasonic stitching system.

Disclosure of Invention

The invention aims to provide an ultrasonic surface rolling method and device with controllable static pressure, which can not only provide the static pressure in the ultrasonic rolling process, but also pre-adjust the static pressure according to the inclination degree of a surface to be processed, and adjust the static pressure in real time according to the actual flatness of the surface of a material, thereby ensuring the processing performance of the surface of the material. In addition, the system consisting of the electromagnet and the permanent magnet belongs to a flexible system, so that the response speed is high, and the static pressure is controlled and adjusted more accurately. Meanwhile, the rolling head and the rolling head shell adopt the principle that like poles of magnets repel each other, so that the rolling head can be stabilized, friction is reduced, and heat dissipation is increased.

The technical scheme for implementing the purpose of the invention is as follows: an ultrasonic surface rolling method and device with controllable static pressure are characterized by comprising an electromagnet, a permanent magnet, a baffle, a pressure sensor, an ultrasonic transducer, an amplitude transformer, a rolling head, an outer sleeve rear cover, an outer sleeve, an amplitude transformer guide sleeve, a rolling head mounting shell, a sensor retainer, a fastening screw, an infrared displacement sensor and a control system, wherein the electromagnet is fixed on the outer sleeve rear cover; the outer sleeve, the outer sleeve rear cover, the electromagnet, the amplitude transformer guide sleeve and the rolling head mounting shell are in a fixed state, and the rest are in a synchronous floating state; the infrared displacement sensor is fixed on the sensor holder, and the sensor holder is fixed on the outer sleeve through a fastening screw.

The magnetic force between the electromagnet and the permanent magnet provides static pressure and maintains the stability of the static pressure.

The distance between the electromagnet and the permanent magnet can be adjusted, and then the magnetic force coefficient between the electromagnet and the permanent magnet is changed.

The outer sleeve, the outer sleeve rear cover, the baffle, the amplitude transformer guide sleeve and the like are all made of non-ferromagnetic materials.

The contact part of the sensor holder and the outer sleeve is made of elastic plastic materials so as to enhance the reliability of connection.

The shoulder of the sensor holder is grooved and can rotate to adjust the angle.

when the two sensors are installed, the two sensors are symmetrically arranged along the symmetrical axis of the sensor holder, and scales capable of displaying the linear distance between the two sensors are marked on the sensor holder according to angles.

The control system adopts neural network PID control, uses BP algorithm, and utilizes the suspension gap between the electromagnet and the permanent magnet as experimental training data, so that the overshoot is small, the rigidity is large, and the robustness is better.

The rolling head and the rolling head mounting shell adopt homopolar permanent magnets, the rolling head is always located in the center of an inner hole of the rolling head mounting shell, and heat dissipation can be increased while friction between the rolling head and a rolling head shell is reduced.

In addition, the present invention provides a rolling method comprising: the infrared displacement sensors are fixed on the sensor holder, the positions of the infrared displacement sensors can be adjusted according to the size of a workpiece, the two sensors are enabled to simultaneously move to cover the whole workpiece plane along the X-axis or Y-axis direction of the machine tool or any one of the sensors is enabled to respectively move to cover the whole workpiece plane along the X-axis and Y-axis directions of the machine tool according to actual conditions before formal machining, the control system uniformly records parameters of each point on a moving track according to a preset program, linear fitting is respectively carried out in the X-axis and Y-axis directions of the machine tool, the levelness of the workpiece is obtained through analysis, and the change range of static pressure is planned.

Compared with the prior art, the invention has the following remarkable advantages:

1. The static pressure is provided by the magnetic force between the electromagnet and the permanent magnet, the structure is simple, and the response speed is high.

2. The system composed of the electromagnet and the permanent magnet belongs to a flexible system, and the elastic coefficient is adjustable, so that the stability of static pressure can be automatically maintained.

3. The workpiece mounting requirement is reduced, the levelness of the surface to be processed is detected in advance, the static pressure range is set, the pressure sensor detects the static pressure in real time, whether the static pressure is in the preset range or not is judged, the accuracy is higher, and the automation degree is higher.

4. The relative positions of the rolling head and the rolling head mounting shell are kept stable, abrasion is reduced, heat dissipation is increased, the service lives of the rolling head and the rolling head mounting shell are prolonged, and the processing quality of parts is improved.

Drawings

FIG. 1 is a schematic view of the structure of the present invention

FIG. 2 is a schematic view showing the structure of a flatness detecting section of a work surface according to the present invention

FIG. 3 is a top view of the sensor holder of the present invention

FIG. 4 is a diagram of the movement path of the infrared displacement sensor according to the present invention

In the figure: 1. an outer sleeve rear cap; 2. an outer sleeve; 3. an electromagnet; 4. a permanent magnet; 5. a baffle plate; 6. a pressure sensor; 7. an ultrasonic transducer; 8. an amplitude transformer; 9. a guide sleeve of the amplitude transformer; 10. a rolling head mounting shell; 11. rolling a head; 12. an infrared displacement sensor; 13. fastening screws; 14. a sensor holder; 15. a control system; 16. a sliding groove.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

An ultrasonic surface rolling method and device with controllable static pressure, as shown in fig. 2 and 3, an infrared displacement sensor 12 is uniformly fixed on a sensor holder 14 by two fastening screws 13, before operation, a shoulder of the sensor holder 14 is rotated to adjust the position of a sliding groove 16, if a workpiece is larger, as shown in fig. 4(a), two sensors can be simultaneously positioned above the surface of the workpiece, the position of the infrared displacement sensor 12 is adjusted, so that the two infrared displacement sensors 12 are both positioned right above the surface to be processed, and are moved to cover the whole workpiece plane along the X-axis (Y-axis) direction of a machine tool, if the workpiece is smaller, as shown in fig. 4(b), two sensors cannot be simultaneously positioned above the surface of the workpiece, the position of the infrared displacement sensor 12 is adjusted, so that one of the two sensors is positioned right above the surface to be processed, and are respectively moved to cover the whole workpiece plane along the X-axis and the Y-axis directions, the control system uniformly records parameters of each point on the moving track according to a preset program, and respectively performs linear fitting in the X-axis direction and the Y-axis direction of the machine tool, so as to analyze and obtain the levelness of the workpiece and plan the change range of the static pressure. For example, when the processing surface inclines upward relatively along the working direction, the load pressure will also increase, the current introduced into the electromagnet 3 should be reduced correspondingly according to the levelness of the processing surface, the magnetic force is weakened, and further the static pressure is maintained stable; when the working direction relative downward sloping of working face is followed, load pressure diminishes, lets in the electric current and should make corresponding increase according to the levelness of working face in the electro-magnet 3, and the magnetic force reinforcing, and then makes the static pressure maintain stably. The details are as follows: the initial position of the rolling head is taken as the origin of coordinates, the number n of sampling points can be obtained by counting by a control system and can also be manually input, and the distance of the sampling points can be manually input and can also be automatically controlled by a program.

In the first case: two sensors a and b are adopted, and every distance d₁Taking a sampling point, the distance between two sensors is 2d₂The measured values are respectively a₁,a₂,……,a_nAnd b₁,b₂,……,b_n；

Respectively calculate a_i+b_iAverage value z of_i(i ═ 1,2, … …, n), a set of data points (d) is obtained₁,0,z₁)(2d₁,0,z₂)……(nd₁,0,z_n) Calculating by adopting a least square method to obtain a linear equation I; respectively calculate Obtain a groupData points ((n +1) d)₁/2,d₂,Z₁)((n+1)d₁/2,-d₂,Z₂) Calculating to obtain a linear equation II; and (5) obtaining a plane equation by using a simultaneous equation.

In the second case: only a sensor c is adopted, the distances of sampling points along the X-axis direction and the Y-axis direction are d, and the measured numerical values are c respectively₁,c₂,……,c_nAnd f₁,f₂,……,f_n；

Respectively obtain a set of data points (d,0, c)₁)(2d,0,c₂)……(nd,0,c_n) Calculating by adopting a least square method to obtain a linear equation (c); and a set of data points (0, d, f)₁)(0,2d,f₂)……(0,nd,f_n) Calculating by adopting a least square method to obtain a linear equation (IV); and obtaining a plane equation through a simultaneous equation and an equation.

And then calculating out the flatness and planning the static pressure.

As shown in fig. 1, the pressure sensor 6 measures the magnitude of the static pressure, transmits a signal to the control system, and changes the magnitude of the magnetic force by controlling the magnitude of the current introduced into the electromagnet 3, thereby changing the static pressure required by rolling or maintaining the stability of the static pressure. For example, when the machined surface has a bulge, the load pressure is increased, the signal of the pressure sensor 6 is changed, the control system 15 controls the current introduced into the electromagnet 3 to be correspondingly reduced, the magnetic force is weakened, and the static pressure is kept stable; when the machined surface is provided with a pit, the load pressure is reduced, the signal of the pressure sensor 6 is changed, the control system 15 controls the current introduced into the electromagnet 3 to be correspondingly reduced, the magnetic force is weakened, and then the static pressure is kept stable.

As shown in fig. 1, the rolling head 11 and the rolling head mounting shell 10 employ homopolar electromagnets, and according to the principle that homopolar repulsion of magnets occurs, the rolling head 11 may be located at the center of the inner hole of the rolling head mounting shell 10 and does not contact with each other, so that friction force therebetween is greatly reduced, and heat dissipation is increased.

The system composed of the electromagnet 3, the permanent magnet 4, the rolling head 11 and the rolling head mounting shell 10 belongs to a flexible system, and can automatically maintain the stability of static pressure within a certain range.

The foregoing are only some embodiments of the invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.