A design method to improve the repeatability of wire drawing sensor winding

Abstract

The present invention relates to a design method for improving the repeatability of winding of a rope sensor, comprising the following steps: structural design: determining the wire binding position of the inner end of the wire rope, and opening a spiral rope groove on the surface of the winding shaft with the wire binding position as the starting point of the spiral rope groove; constraint design: determining the design constraints based on the outer dimensions and working range of the rope sensor, including outer dimension constraints, coil spring working circle constraints, spiral rope groove constraints, wire entry angle constraints, and wire change angle constraints; determining the entrance position: preliminarily obtaining all wire rope entrance positions that meet the constraint conditions based on the design constraints, and performing actual winding repeatability tests, and finally obtaining the optimal wire rope entrance position. Compared with the prior art, the present invention has the advantages of simple and convenient design, comprehensive consideration, and greatly improved repeatability indicators.

Description

Technical Field

[0001] The invention relates to the field of intelligent sensor production and manufacturing, and in particular to a design method for improving the winding repeatability of a pull-wire sensor. Background Art

[0002] Draw-wire sensors are mainly used in the field of engineering machinery to monitor the length changes of cylinders, booms and other parts. The product structure of draw-wire sensors is as follows: Figure 1 As shown, the main working parts include a scroll spring 1 (coil spring), a rotating shaft 2, a winding wheel 3, a wire rope 4, a worm 5, a worm wheel 6, a worm wheel shaft 7 (magnetic steel), a circuit board 8 and an auxiliary housing and other parts.

[0003] Its working principle is: when the wire rope is pulled out, the wire rope drives the winding wheel to rotate, and the winding wheel rotates synchronously with the shaft and worm; the worm and the worm gear are meshed, so that the worm gear and the worm gear shaft (magnet) rotate synchronously; when the magnet rotates, its magnetic field change is recognized by the Hall chip on the circuit board and converted into an angle signal, and the final length signal is obtained through the circuit board processing. When the wire rope is recovered, the vortex spring drives the shaft to rotate, and the length change of the wire rope is linearly related to the angle change of the worm gear shaft (magnet), and the relationship is:

[0004]

[0005] in, is the change in wire rope length, is the angle change of the magnetic steel, D is the outer diameter of the winding wheel, Z 1 is the number of worm teeth, Z 2 is the number of worm gear teeth.

[0006] Due to the compact structure and small size of the pull-rope sensor, when the wire rope is completely wound on the winding wheel, its distribution characteristics are multi-strand and multi-layer cross-overlapping distribution. When the wire rope is repeatedly pulled out and retracted, the distribution state of the wire rope is irregular and the difference is relatively large, which is manifested as the length change of the wire rope and the angle change of the winding wheel cannot be accurately synchronized, which leads to the repeatability and accuracy of the sensor being relatively low. Therefore, a method is needed to improve the winding repeatability of the pull-rope sensor. Summary of the invention

[0007] In order to solve the technical problems in the background technology, the present invention provides a design method for improving the repeatability of the winding of a pull rope sensor, so as to optimize the position of the entrance of the wire rope, comprising the following steps:

[0008] Structural design: Determine the wire binding position at the inner end of the wire rope, and use the wire binding position as the starting point of the spiral rope groove to open a spiral rope groove on the surface of the winding shaft;

[0009] Constraint design: Determine the design constraints based on the overall dimensions and working range of the rope sensor, including overall dimension constraints, spring working turns constraints, spiral rope groove constraints, line entry angle constraints, and line change angle constraints;

[0010] Determine the entry position: Based on the design constraints, preliminarily obtain all wire rope entry positions that meet the constraints, and conduct actual winding repeatability tests to ultimately obtain the optimal wire rope entry position.

[0011] Furthermore, in the structural design:

[0012] The upper edge or lower edge of the winding shaft of the winding wheel is used as the binding position of the inner end of the wire rope.

[0013] Furthermore, the parameters of the wire rope entrance position include a height difference H1 between the wire rope entrance position and the wire binding position and an axial distance X between the wire rope entrance position and the winding wheel.

[0014] Furthermore, the external dimension constraints are specifically:

[0015] The diameter of the coil spring is not larger than the inner diameter of the outer shell of the rope sensor, and the outer diameter of the winding wheel is not larger than the inner diameter of the outer shell of the rope sensor.

[0016] Furthermore, the coil spring working turns constraint is specifically:

[0017] The product of the number of working turns of the coil spring and the circumference of the winding wheel is equal to the working range, and the number of working turns of the coil spring is equal to the product of the number of layers of wire rope n and the number of strands of each layer of wire rope m, then:

[0018]

[0019]

[0020] Among them, L is the working range of the pull rope sensor, N is the number of working turns of the winding spring, D is the outer diameter of the winding wheel, n is the number of layers of wire rope, and m is the number of strands of each layer of wire rope;

[0021] When designing the actual winding of the wire rope sensor, the margin between the actual length of the wire rope and the sensor range is considered, and the following is true:

[0022] .

[0023] Furthermore, the spiral rope groove constraint is specifically:

[0024]

[0025] Among them, p is the pitch of the spiral rope groove, d is the diameter of the wire rope, and the wire rope diameter is selected to meet the minimum force requirement of the wire rope when in use.

[0026] Furthermore, the line angle constraint is specifically:

[0027]

[0028]

[0029]

[0030] in, is the wire rope entry angle, is the helix angle of the spiral rope groove, and p is the pitch of the spiral rope groove.

[0031] Furthermore, the line change angle constraint is specifically:

[0032]

[0033]

[0034] in, is the wire rope change angle, H2 is the reverse height difference between the wire rope entrance position and the wire binding position, The critical value of the line change angle is to ensure the uniform and regular arrangement of the second layer of wire ropes.

[0035] Furthermore, the winding width of the winding wheel satisfies:

[0036]

[0037]

[0038] in, The wire winding width of the reel.

[0039] Furthermore, the line change angle critical value The value range is =[5.9°, 6.3°].

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] In response to the problem of inconsistent rope winding occurring in the production process of a rope draw sensor, the present invention proposes a design method for improving the repeatability of rope draw sensor winding. The method adds a spiral rope groove on the surface of a winding shaft of a winding wheel, so that the wire rope can be arranged along the spiral rope groove during winding to prevent the wire rope from being wound in a disorderly manner. In addition, the present invention combines the spiral rope groove, the wire binding position of the wire rope, and the constraint design of the wire entry angle and the wire change angle to obtain a reasonable value of the wire rope entrance position, which can greatly improve the uniformity and regularity of the wire rope winding. Compared with the existing winding scheme, the repeatability index of the sensor can be improved by more than 80%, reaching 0.10%. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural schematic diagram of the rope sensor;

[0043] Figure 2 is a flow chart of the method of the present invention;

[0044] Figure 3 A schematic diagram of size parameters. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0046] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0047] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They 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 a limitation on the present invention.

[0048] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0049] In the description of this embodiment, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it 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 this embodiment can be understood according to specific circumstances.

[0050] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0051] To solve the problem of low sensor repeatability and accuracy caused by the inability to accurately synchronize the length change of the wire rope with the angle change of the winding wheel, such as Figure 2 and 3 As shown, the present invention provides a design method for improving the repeatability of winding of a draw wire sensor, comprising the following steps:

[0052] 1) Improve the structure of the existing wire rope sensor reel, use the bottom edge or top edge of the outer surface of the winding shaft of the reel as the wire binding position of the inner end of the wire rope, and add a spiral rope groove on the outer surface of the winding shaft with the wire binding position of the inner end of the wire rope as the starting point;

[0053] The present invention selects the bottom edge or the top edge of the outer surface of the winding shaft of the winding wheel as the wire binding position of the inner end of the wire rope, so that when the wire rope is wound, it will be reciprocated from bottom to top or from top to bottom, so that the number of arranged strands in each layer can be the same and the turning point is located at the top or bottom. In the present invention, the middle part of the outer surface of the winding shaft of the winding wheel cannot be selected as the wire binding position of the inner end of the wire rope, so as to avoid the turning point in the middle, which will make the middle part too convex when the wire rope is wound, resulting in poor winding repeatability.

[0054] It is worth noting that the purpose of adding spiral rope grooves to the outer surface of the winding shaft in the present invention is to enable the first layer of steel wire rope to cover the entire layer under the guidance of the spiral rope grooves, while the second layer and subsequent steel wire ropes are pulled by the line change angle between the steel wire ropes of each layer and the entrance position to complete the arrangement of the subsequent steel wire ropes. Therefore, the angle of the line change angle needs to be considered during design. If the line change angle is too small, the distance between the entrance position and the axis of the winding wheel will be too large, exceeding the shell size limit. If the line change angle is too large, it will not be able to reach the turning point and will turn back prematurely, and the winding shaft cannot be fully covered.

[0055] 2) Based on the external dimensions and working range of the rope-drawing sensor, a variety of constraints are considered for constraint design, including external dimension constraints, coil spring working turns constraints, spiral rope groove constraints, line entry angle constraints, and line change angle constraints. Each constraint is described in detail below.

[0056] Dimensional constraints: According to the actual application environment requirements of the draw-wire sensor, determine the working range of the draw-wire sensor, and design the shape and size of the sensor housing. Since the winding wheel and the coil spring are both arranged inside the winding wheel compartment and the coil spring compartment of the housing, the maximum size of the coil spring and the winding wheel is limited by the housing size, that is, the coil spring diameter is not larger than the inner diameter of the draw-wire sensor housing, and the outer diameter of the winding wheel is not larger than the inner diameter of the draw-wire sensor housing;

[0057] Constraints on the number of working turns of the coil spring: When selecting the coil spring model, since the maximum radius of the coil spring is equal to the inner diameter of the outer shell of the draw wire sensor, it is necessary to roughly determine the number of working turns of the coil spring according to the working range of the draw wire sensor, and also determine the thickness of the coil spring according to the requirements of the coil spring rebound force. The thicker the coil spring, the fewer the working turns and the greater the rebound force. The thinner the coil spring, the more the working turns and the smaller the rebound force. Therefore, in the present invention, the appropriate coil spring model is finally determined according to the requirements of the working range and the coil spring rebound force, and then:

[0058] The product of the number of working turns of the coil spring and the circumference of the winding wheel is theoretically equal to the working range, and the number of working turns of the coil spring is equal to the product of the number of layers n of the wire rope and the number m of the wire rope strands in each layer, then:

[0059]

[0060]

[0061] Among them, L is the working range of the pull rope sensor, N is the number of working turns of the winding spring, D is the outer diameter of the winding wheel, n is the number of layers of wire rope, and m is the number of strands of each layer of wire rope;

[0062] In addition, when designing the actual winding of the pull-wire sensor, the allowance of the wire rope is considered, and then:

[0063]

[0064] The wire rope margin is used for pre-tensioning the coil spring and the connection between the wire binding position and the entry position;

[0065] Spiral rope groove constraint: The purpose of opening a spiral rope groove on the outer surface of the winding shaft is to allow the first layer (innermost layer) of steel wire rope to be laid on the entire layer under the guidance of the spiral rope groove. Therefore, the shape and size of the spiral rope groove should be able to at least accommodate the steel wire rope. In the present invention, the cross-sectional shape of the spiral rope groove is selected to be semicircular, and the pitch p of the spiral rope groove satisfies The choice of wire rope diameter d is subject to the requirements of actual working conditions, that is, the diameter of the wire rope must meet the minimum force requirements during use, and it is also necessary to ensure the smoothness of pulling and pulling, and it must not get stuck and cannot be recovered. In addition, the thickness of the wire rope must also be considered to affect the appearance.

[0066] Entry angle constraint and line change angle constraint: After the present invention adds a spiral rope groove on the outer surface of the winding shaft, the first layer of wire rope can be fully laid, and the second and subsequent wire ropes are pulled by the line change angle between the wire ropes of each layer and the entry position to complete the arrangement of the subsequent wire ropes. Therefore, the angle of the line change angle needs to be considered during design. If the line change angle is too small, the distance between the entry position and the axial center of the winding wheel will be too large, exceeding the shell size limit, and if the line change angle is too large, it will not be able to reach the turning point and will turn back prematurely.

[0067] Therefore, in the present invention, the line angle constraint is specifically:

[0068]

[0069]

[0070]

[0071] in, is the wire rope entry angle, is the helix angle of the spiral rope groove.

[0072] The line change angle constraints are as follows:

[0073]

[0074]

[0075] in, is the wire rope change angle, H2 is the reverse height difference between the wire rope entrance position and the wire binding position, The critical value of the line change angle is to ensure the uniform and regular arrangement of the second layer of wire ropes.

[0076] 3) Based on the above constraints, a set of all wire rope entrance positions that meet the constraints is obtained. The wire rope entrance position parameters specifically include the height difference H1 between the wire rope entrance position and the wire binding position and the axial distance X between the wire rope entrance position and the winding wheel. After obtaining multiple preliminary position parameters {(H1, X)} that meet the constraints, the winding repeatability is optimized and screened, and the position parameter corresponding to the minimum winding repeatability is selected. , which is the optimal design solution, and finally the design of improving the repeatability of the rope sensor winding is completed.

[0077] This example takes the design of a large-range draw-wire sensor product as an example for further explanation. In this example, the working range of the large-range draw-wire sensor is L=8300mm, and the outer diameter of the winding wheel is set to D=80mm according to the product's appearance dimensions. The wire rope with a diameter of d=0.8mm is selected according to the force requirements of the wire rope. Combined with the working range L and the outer diameter D of the winding wheel, it is determined that the number of working turns N of the winding spring should be no less than 33 turns, that is, According to the actual application, taking into account the margin and pre-tension of the wire rope, the working number of coil springs N is between 33 and 36 turns;

[0078] like Figure 3 As shown, in this example, a wire binding position A is set at the lower edge of the winding shaft of the winding wheel, and the wire rope entrance position B is located on the left side of the winding wheel. On the surface of the winding shaft of the winding wheel, a spiral groove is opened with the wire binding position A as the starting point, that is, the spiral rope groove. The groove cross-section of the spiral rope groove is semicircular, and its pitch p is selected as 1mm according to the constraint limit, then the spiral angle .

[0079] In this example, the wire rope entrance position includes two parameters, namely, the height difference H1 between the wire rope entrance position B and the wire binding position A and the axial distance X between the wire rope entrance position and the winding wheel. H2 represents the height difference between the upper edge position C of the winding wheel corresponding to the wire binding position A and the wire rope entrance position B. The width of the winding wheel In the specific design process, the width of the winding wheel , the width of the reel The larger the value, the larger the number of wire rope strands m that can be accommodated in each layer, the smaller the number of wire rope layers n, and the more uniform the winding. However, the distance X between the wire rope entrance and the axis of the winding wheel will become larger, resulting in the entire rope sensor product being too large. Conversely, the width of the winding wheel The smaller it is, the smaller the number m of wire rope strands that can be accommodated in each layer, and the more layers n of wire rope are arranged. Although it can reduce the axial distance X between the wire rope entrance position and the winding wheel and control the product volume of a rope sensor, it will lead to too many winding stacking layers, and the winding repeatability and length measurement consistency will decrease. Therefore, it is necessary to comprehensively consider the parameter setting of the wire rope entrance position.

[0080] Regarding how to design the wire rope entrance position in the present invention, it is worth noting that it is necessary to ensure that the first layer of wire ropes are evenly and regularly arranged, and that the subsequent wire ropes are evenly and regularly arranged. Therefore, the present invention constrains the entry angle and the line change angle. After actual measurement, the specific constraints of the entry angle in this example are:

[0081] , ,Right now .

[0082] The specific constraints of the line change angle are:

[0083] ,

[0084] In this example, according to actual calculation and test, The value range is [5.9°, 6.3°]. In addition, for different models and sizes of rope sensors, The value of needs to be adjusted accordingly.

[0085] According to the above design constraints, multiple sets of position parameters {(H1,X)} can be preliminarily determined, and the optimal position parameters can be obtained through optimization screening through winding repeatability test, and finally the design of improving the winding repeatability of the rope sensor is completed.

[0086] The winding repeatability test is to place the rope sensor to be tested on the test fixture, set a calibration point at a set interval (in this case, a calibration point is set every 400mm), and repeatedly stretch the steel wire rope of the rope sensor to be tested. The measured values ​​of each calibration point during each forward and reverse stroke are recorded, and then the mean and standard deviation of the measured values ​​of all the calibration points are statistically calculated, and the limit value of the maximum standard deviation at a confidence level of 0.95 is calculated to obtain the winding repeatability.

[0087] As shown in the following table, according to the design method of the present invention, the final design parameters of the large-range pull-wire sensor of this example are shown in Table 1. After actual verification, the design of the wire rope entrance position can improve the winding repeatability index by more than 80%, up to 0.10%.

[0088] It can be seen from Table 1 that the number of layers n of the wire rope and the number m of strands in each layer of the wire rope are not positive integers. In practice, the last layer of wire rope may not be fully arranged and cannot be wound a full circle, so it can be expressed in decimal form.

[0089] In summary, the present invention aims at the problem of inconsistent rope winding occurring in the production process of the rope sensor, and proposes a design method for improving the repeatability of the rope winding of the rope sensor. This method adds a spiral rope groove on the surface of the winding shaft of the winding wheel, so that the wire rope can be arranged along the spiral rope groove when winding, thereby preventing the wire rope from being wound in a disorderly manner. In addition, the present invention combines the constraint design of the spiral rope groove, the wire binding position of the wire rope, and the wire entry angle and the wire changing angle to obtain a reasonable value of the entrance position of the wire rope, which can greatly improve the winding uniformity and regularity of the wire rope. Compared with the existing winding scheme, the repeatability index of the sensor can be improved by more than 80%, reaching 0.10%.

[0090] Table 1 Final design parameters of the large-range draw-wire sensor

[0091] parameter unit Example 1 Example 2 L mm 8300 8300 D mm 80 80 w mm 7.2 8 d mm 0.8 0.8 p mm 1 1 β ° 1.43 1.43 m 7.2 8 n 4.587 4.128 α ° 1.37 1.49 γ ° 5.88 4.46 <![CDATA[γ max ]]> ° 6.3 5.9 H1 mm 1.6 2 X mm 67 77 Repeatability error 0.10% 0.10%

[0092] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A design method for improving the repeatability of winding of a draw wire sensor, characterized in that: The following steps are involved: Structural design: Determine the wire binding position at the inner end of the wire rope, and use the wire binding position as the starting point of the spiral rope groove to open a spiral rope groove on the surface of the winding shaft; Constraint design: Determine the design constraints based on the overall dimensions and working range of the rope sensor, including overall dimension constraints, spring working turns constraints, spiral rope groove constraints, line entry angle constraints, and line change angle constraints; Determine the entry position: Based on the design constraints, preliminarily obtain all wire rope entry positions that meet the constraints, and conduct actual winding repeatability tests to ultimately obtain the optimal wire rope entry position.

2. A design method for improving the winding repeatability of a draw wire sensor according to claim 1, characterized in that: In the structural design: The upper edge or lower edge of the winding shaft of the winding wheel is used as the binding position of the inner end of the wire rope.

3. A design method for improving the winding repeatability of a draw wire sensor according to claim 1, characterized in that: The parameters of the wire rope entrance position include a height difference H1 between the wire rope entrance position and the wire binding position and an axial distance X between the wire rope entrance position and the winding wheel.

4. A design method for improving the winding repeatability of a draw wire sensor according to claim 1, characterized in that: The specific dimensions constraints are: The diameter of the coil spring is not larger than the inner diameter of the outer shell of the rope sensor, and the outer diameter of the winding wheel is not larger than the inner diameter of the outer shell of the rope sensor.

5. A design method for improving the winding repeatability of a draw wire sensor according to claim 1, characterized in that: The coil spring working turns constraint is specifically: The product of the number of working turns of the coil spring and the circumference of the winding wheel is equal to the working range, and the number of working turns of the coil spring is equal to the product of the number of layers of wire rope n and the number of strands of each layer of wire rope m, then: Among them, L is the working range of the pull rope sensor, N is the number of working turns of the winding spring, D is the outer diameter of the winding wheel, n is the number of layers of wire rope, and m is the number of strands of each layer of wire rope; When designing the actual winding of the wire rope sensor, the margin between the actual length of the wire rope and the sensor range is considered, and the following is true: 。 6. A design method for improving the winding repeatability of a draw wire sensor according to claim 1, characterized in that: The spiral rope groove constraint is specifically: Among them, p is the pitch of the spiral rope groove, d is the diameter of the wire rope, and the wire rope diameter is selected to meet the minimum force requirement of the wire rope when in use.

7. A design method for improving the winding repeatability of a draw wire sensor according to claim 3, characterized in that: The line angle constraint is specifically: in, is the wire rope entry angle, is the helix angle of the spiral rope groove, and p is the pitch of the spiral rope groove.

8. A design method for improving the winding repeatability of a draw wire sensor according to claim 7, characterized in that: The line change angle constraint is specifically: in, is the wire rope change angle, H2 is the reverse height difference between the wire rope entrance position and the wire binding position, The critical value of the line change angle is to ensure the uniform and regular arrangement of the second layer of wire ropes.

9. A design method for improving the winding repeatability of a draw wire sensor according to claim 8, characterized in that: The winding width of the reel satisfies: in, The wire winding width of the reel.

10. A design method for improving winding repeatability of a draw wire sensor according to claim 8, characterized in that: The critical value of the line change angle The value range is =[5.9°, 6.3°].

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