Workpiece micro-deformation adjusting mechanism based on clamping force feedback

Abstract

The invention discloses a workpiece micro-deformation adjusting mechanism based on clamping force feedback. The workpiece micro-deformation adjusting mechanism comprises a bottom plate, a clamp base is fixedly installed at the top of the bottom plate, a clamp positioning plate is connected to the clamp base, a positioning groove is formed in the clamp positioning plate, and a cutting groove is formed in the clamp positioning plate. By additionally arranging the cutting groove, interference deformation and over-positioning errors can be compensated in a self-adaptive mode; compared with other factors, the distance from the top point of the upper surface of the inclined groove to the upper surface of the clamp positioning plate has the maximum influence on the maximum stress value, the length of the cutting groove has the maximum influence on the maximum displacement value, and under the action of the same end linear load, the maximum displacement value is increased along with the increase of the length of the cutting groove; the maximum stress value is reduced along with the increase of the distance from the top point of the upper surface of the chute to the upper surface of the clamp positioning plate, the cutting groove is additionally arranged in the positioning groove, the system rigidity is properly reduced, and over-positioning is ingeniously utilized to ensure the positioning precision.

Description

Technical Field

[0001] The invention relates to the technical field of adjustment mechanisms, and in particular to a workpiece micro-deformation adjustment mechanism based on clamping force feedback. Background Art

[0002] In the machining process of most parts, fixtures are needed as a link to connect the machine tool and the workpiece to ensure machining accuracy and improve production efficiency. However, with the diversification of product structure and the development of modern digital manufacturing production mode, problems such as low standardization of traditional fixtures, long downtime and rigid production line adjustment are becoming increasingly prominent. The flexible fixture of the zero-point positioning system can achieve positioning and locking at the same time, providing an opportunity to effectively solve the above problems and is becoming more and more widely used in the equipment manufacturing field.

[0003] Most of the focus is on the application of zero-point positioning systems in various production lines. In order to ensure the positioning and clamping effects when dealing with the variable weight of the positioning joint and the workpiece and the external load during processing, the zero-point positioning device is usually equipped with multiple positioning slots. However, this will inevitably cause over-positioning, which is not convenient for processing the workpiece micro-deformation adjustment based on the clamping force feedback. Summary of the invention

[0004] The object of the present invention is to provide a workpiece micro-deformation adjustment mechanism based on clamping force feedback, so as to solve the technical problem in the above background technology that it is inconvenient to process the workpiece micro-deformation adjustment based on clamping force feedback.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a workpiece micro-deformation adjustment mechanism based on clamping force feedback, comprising a base plate, a fixture base is fixedly installed on the top of the base plate, a fixture positioning plate is connected to the fixture base, a positioning groove is arranged on the fixture positioning plate, and a cutting groove is arranged on the fixture positioning plate.

[0006] Preferably, the cutting groove is located on one side of the positioning groove.

[0007] Preferably, the positioning grooves are arranged in a staggered manner.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] 1. The present invention can adaptively compensate for interference deformation and over-positioning errors by adding cutting grooves; compared with other factors, the distance from the vertex of the upper surface of the inclined groove to the upper surface of the fixture positioning plate has the greatest influence on the maximum stress value, while the length of the cutting groove has the greatest influence on the maximum displacement value. Under the action of the same end line load, the maximum displacement value increases with the increase of the length of the cutting groove, and the maximum stress value decreases with the increase of the distance from the vertex of the upper surface of the inclined groove to the upper surface of the fixture positioning plate. A cutting groove is added in the positioning groove, the system rigidity is appropriately reduced, and over-positioning is cleverly used to ensure positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of a workpiece micro-deformation adjustment mechanism based on clamping force feedback of the present invention;

[0011] Figure 2 For the present invention Figure 1 A schematic diagram of the enlarged structure in the middle;

[0012] Figure 3 It is a schematic diagram of the orthogonal test factors and level design of the present invention;

[0013] Figure 4 It is a schematic diagram of the orthogonal simulation displacement and stress calculation results of the present invention;

[0014] Figure 5 This is a schematic diagram of the influence of the test index of the present invention on the average value of the displacement and ;

[0015] Figure 6 It is a schematic diagram of the influence of the test indicators of the present invention on the average values ​​of stress and .

[0016] In the figure: 1. bottom plate; 2. fixture base; 3. fixture positioning plate; 4. positioning groove; 5. cutting groove. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0019] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] Example 1: Please refer to Figures 1 to 6, an embodiment provided by the present invention: a workpiece micro-deformation adjustment mechanism based on clamping force feedback, comprising a bottom plate 1, a fixture base 2 is fixedly installed on the top of the bottom plate 1, a fixture positioning plate 3 is connected to the fixture base 2, a positioning groove 4 is arranged on the fixture positioning plate 3, a cutting groove 5 is arranged on the fixture positioning plate 3, the cutting groove 5 is located on one side of the positioning groove 4, the positioning grooves 4 are staggered, and the cutting groove 5 is added in the positioning groove 4, which can appropriately reduce the rigidity of the system, and cleverly use the positioning to ensure the positioning accuracy. After the positioning plate is installed and works normally Through the three-coordinate measuring instrument, it was found that the force-bearing end of the cutting groove 5 sank 2.05μm in the negative direction of the Z axis, indicating that the addition of the cutting groove 5 can indeed reduce the rigidity of the system and solve the positioning problem. When a concentrated load of 100N is applied along the negative direction of the Z axis, the maximum displacement of the force-bearing end of the cutting groove 5 is 2.718μm. It is equivalent to the finite element model. After conversion, the load to be set is 91.827N. Therefore, in the following simulation scheme, the concentrated load is uniformly set to 91.827N, and the numerical solution is used to observe the beam in The displacement and stress under the action of concentrated force, find out the maximum deformation and maximum stress points, and analyze the causes of formation, provide predictive guidance for the optimization design of cutting groove 5, the parameter combination of cutting groove 5 length A, cutting groove 5 width B, angle C with the horizontal line and distance D (cantilever beam thickness) from the vertex of the upper surface of the inclined groove to the upper surface of the fixture positioning plate will significantly affect the stiffness and stress of the structure, and different geometric parameters have different effects and degrees of influence on the stiffness and stress of the fixture. In order to determine the effect of each geometric parameter on the stiffness and stress of the fixture and obtain the optimal combination within the simulation parameter range, an orthogonal simulation test is designed, and the length, width and angle of cutting 5 and the thickness of the cantilever beam are set as four factors, and each factor takes three levels, thus forming 9 groups of orthogonal simulation combinations of four factors and three levels as shown in Table 3. The maximum stress and maximum displacement are important indicators for evaluating the effect of cutting groove 5 and the performance of the positioning system. The range R refers to the difference between the maximum and minimum values ​​of the average values ​​of the test indicators corresponding to each level in each column. The larger the range, the greater the influence of the column on the test indicator. Among them, Kjm represents the sum of the test indicators corresponding to the level of the jth (j=A, B, C, D) column factor m (m=1, 2, 3), and kjm is the average value of Kjm. The optimal level and optimal combination of the jth column factor can be judged by kjm. The range analysis of the solution results in Table 4 shows that the range R of the influence of the length of the cutting groove 5, the width of the cutting groove 5, the angle with the horizontal line, and the thickness of the cantilever beam on the displacement and stress are 5.889, 5.241, 4.104, 2.521 and 22.070, 13.200, 28.810, 84.913 respectively.Therefore, the influence of each factor on displacement U is A>B>C>D from large to small, and the influence on stress S is D>C>A>B from large to small. Within the set parameter range, the length A of cutting groove 5 and the width B of cutting groove 5 are positively correlated with the average of displacement and ; the thickness D of cantilever beam is negatively correlated with the average of displacement and ; with the increase of the angle C between cutting groove 5 and the horizontal line, the average of displacement and increases first and then decreases, and does not show a linear relationship. If the minimum displacement is taken as the goal, the optimal horizontal combination is predicted to be A1B1C1D3, that is, the length A of cutting groove 5 is 2.67mm, the width B is 0.6mm, the angle C is 2°, and the thickness D of cantilever beam is 2.9mm. The influence of test indicators A, B, C, and D on the average of stress and . Within the set parameter range, the length A of the cutting groove 5 and the width B of the cutting groove 5 are positively correlated with the average value of the stress and ; as the angle C between the cutting groove and the horizontal line increases, the average value of the stress and first decreases and then increases, which is not a linear relationship; while the thickness D of the cantilever beam is negatively correlated with the average value of the stress and . If the goal is to minimize the stress on the cantilever beam, it is predicted that the optimal horizontal combination is A1B1C2D3. At this time, the length A of the cutting groove 5 is 2.67mm, the width B is 0.6mm, the angle C is 4°, and the thickness D of the cantilever beam is 2.9mm. By observing the linear slope of the point-line graph or the amplitude of the change of the dependent variable with the independent variable in the ordinate, it can be found that the length of the cutting groove 5 has the greatest impact on the displacement, and the thickness of the cantilever beam has the least impact on the displacement. At the same time, it can be observed that the thickness of the cantilever beam has the greatest influence on stress, and the width of the cutting groove 5 has the least influence on stress, which is consistent with the results of the range analysis. Although the orthogonal simulation can compare the relative influence of each factor on the test index, it cannot intuitively reflect the positive and negative effects of each factor on the test index. The gradient test can make up for this shortcoming. Since the length of the cutting groove 5 has the greatest influence on the displacement and the thickness of the cantilever beam has the greatest influence on the stress, it is necessary to set up a gradient test to reveal the influence of the length of the cutting groove 5 and the thickness of the cantilever beam on the size and distribution of displacement and stress, respectively. Keep B = 0.8mm, C = 4°, D = 1.9mm unchanged, and A is 2.67mm, 4.67mm, and 6.67mm respectively. The displacement distribution cloud map under different lengths of the cutting groove 5 is obtained by finite element simulation, and the maximum displacement value is collected to observe the change trend of the maximum displacement with the length of the cutting groove 5. Analysis shows that under the same end line load, the displacement of the constraint end is the smallest, the displacement of the pressure end is the largest, and the maximum displacement value increases with the increase of the length of the cutting groove 5.

[0021] Keep A=4.67mm, B=0.8mm, C=8° unchanged, and take D as 0.9mm, 1.9mm, and 2.9mm respectively. The stress distribution cloud map under different cantilever beam thicknesses is obtained through numerical solution, and the maximum stress value is collected to observe the change trend of the maximum stress with the thickness of the cantilever beam. Analysis shows that, corresponding to the deformation diagram, under the action of the same end line load, the maximum stress is on the bending side of the constraint end and is a tensile stress, and the minimum value is at the compressive end. The reason is that the bending moment at the constraint end is the largest, and the influence of the bending moment on the stress decreases with the increase of the cantilever beam thickness. It can be concluded that increasing the cantilever beam thickness within a certain range can reduce the maximum stress value;

[0022] The orthogonal test method was used to study the order of the influence of the main characteristic parameters of the cutting groove on stress and displacement, and the optimal parameter combination was obtained. The gradient test of the main factors was carried out, and the following conclusions were finally obtained.

[0023] (1) Experimental verification shows that the addition of the cutting groove 5 will cause a certain degree of micro-deformation of the positioning groove 4. By adaptively compensating for the interference deformation and over-positioning error, the accuracy of the zero-point positioning system can be ensured.

[0024] (2) From the range analysis, it can be found that the distance from the top of the upper surface of the inclined groove to the upper surface of the fixture positioning plate has the greatest influence on the maximum stress value, and the width of the cutting groove has the least influence on the stress; while the length of the cutting groove 5 has the greatest influence on the maximum displacement value, and the distance from the top of the upper surface of the inclined groove to the upper surface of the fixture positioning plate has the least influence on the displacement.

[0025] (3) Within the scope of this test, when the characteristic parameter combination used is A1B1C2D3, that is, the length of the cutting groove 5 A = 2.67 mm, the width of the cutting groove 5 B = 0.6 mm, the angle with the horizontal line C = 4°, and the distance from the vertex of the upper surface of the inclined groove to the upper surface of the fixture positioning plate D = 2.9 mm, the stress on the cutting groove is minimal.

[0026] (4) Under the action of the same end linear load, the displacement of the constrained end of the cutting groove 5 is the smallest, the displacement of the compressed end is the largest, and the maximum displacement value increases with the increase of the length of the cutting groove.

[0027] (5) The bending moment on the constrained end of the cutting groove 5 is the largest, and the influence of the bending moment on the stress decreases with the increase of the distance from the upper surface to the top surface of the cutting groove 5. Therefore, the maximum stress occurs at the fixed end of the cutting groove 5, and the minimum stress occurs at the pressure end. Therefore, the maximum stress value can be reduced by increasing the distance from the vertex of the upper surface of the inclined groove to the upper surface of the fixture positioning plate within a certain range.

[0028] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A workpiece micro-deformation adjustment mechanism based on clamping force feedback, comprising a base plate (1), characterized in that: A clamp base (2) is fixedly mounted on the top of the bottom plate (1); a clamp positioning plate (3) is connected to the clamp base (2); a positioning groove (4) is provided on the clamp positioning plate (3); and a cutting groove (5) is provided on the clamp positioning plate (3).

2. The workpiece micro-deformation adjustment mechanism based on clamping force feedback according to claim 1, characterized in that: The cutting groove (5) is located on one side of the positioning groove (4).

3. The workpiece micro-deformation adjustment mechanism based on clamping force feedback according to claim 1, characterized in that: The positioning grooves (4) are arranged in a staggered manner.

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