Design method of the drive groove contour of the disconnect switch dial and the dial and operating mechanism

Abstract

This application relates to a method for designing the profile of a disconnector dial drive slot and a dial and operating mechanism, belonging to the field of disconnector dial technology. The method for designing the profile of a disconnector dial drive slot includes: based on the initial spatial arrangement parameters of the dial rotation center and the transmission structure, the resistance encountered by the disconnector during the closing process is equivalently applied to the dial rotation center, establishing an equivalent total load torque function T_load(α) for the entire closing stroke; based on the initial set current I_test, the current linear thrust F_test of the drive nut is determined; based on the total load torque function T_load(α) and the current linear thrust F_test, the current envelope function (X(α), Y(α)) of the drive slot is determined; based on the current envelope function (X(α), Y(α)), the target envelope function of the drive slot is determined.

Description

Technical Field

[0001] This application relates to the field of disconnector dial technology, and in particular to a method for designing the profile of the drive groove of a disconnector dial and the dial and operating mechanism. Background Technology

[0002] Currently, disconnect switches are crucial electrical devices in power systems, used to isolate power sources and establish clear disconnection points to ensure equipment maintenance and operational safety. With the continuous expansion of power grid capacity, disconnect switches are evolving towards higher voltage, higher current, greater intelligence, miniaturization, and higher reliability. As a device that uses a mechanical structure to achieve electrical functions, the mechanical characteristics of a disconnect switch are the prerequisite and foundation for its electrical performance. Therefore, the reliability of its closing and opening operations largely depends on the performance of its transmission mechanism. In the operating mechanism of a disconnect switch, a motor typically drives a transmission screw via a gear set. The transmission screw drives a drive nut mounted on it to move linearly. The drive nut then contacts the drive groove on the dial through a washer, thereby causing the dial to rotate around its center of rotation and drive the output shaft to complete the closing operation. Therefore, the drive groove of the dial is the key component that converts the linear motion of the drive nut into the rotational motion of the dial, and its contour shape directly determines the force transmission characteristics and motion characteristics of the transmission mechanism.

[0003] Existing disconnect switches typically employ radially or nearly linearly extending slots for their dial drive. The drive nut, driven by a lead screw, moves at a constant or nearly constant linear speed, and through its sleeve, pushes the dial to rotate along the contour of the drive slot. This converts the linear motion of the drive nut into the rotational motion of the dial according to a essentially constant transmission ratio determined by the fixed slot shape. However, during the closing operation of a double-break disconnect switch, its load reaction curve exhibits significant and extremely nonlinear characteristics: in the early and middle stages of the closing action, the mechanism mainly overcomes the frictional resistance of the conventional contact finger springs, resulting in a relatively flat load curve; however, when the moving contact reaches the final stage where it is about to engage with the stationary contact, the system's load resistance curve experiences a steep, step-like increase due to the instantaneous intervention and superposition of the arc contact and self-force contact pressures. The existing dial drive slot does not have a profile optimized for the local resistance peak at this end. When the mechanism reaches this high-resistance section, the equivalent back load felt by the motor increases dramatically. At this time, if the motor output torque is insufficient, it can easily lead to mechanism jamming, incomplete closing, or even motor stall and burnout. If a high-power motor is blindly selected to overcome this instantaneous dead-point peak, it will result in redundant equipment size, high manufacturing costs, and a significant waste of power during the stable period before closing. Therefore, the existing dial drive slot cannot reliably overcome the resistance peak at the closing end while making reasonable use of motor power, and its profile urgently needs targeted optimization. Summary of the Invention

[0004] To overcome the above problems, this application provides a method for designing the profile of the drive slot for a disconnect switch dial.

[0005] Firstly, the method for designing the contour of the disconnector switch dial drive groove provided in this application adopts the following technical solution: A method for designing the profile of a disconnect switch dial drive groove includes: Based on the initial spatial arrangement parameters of the dial rotation center and the transmission structure, the resistance of the disconnecting switch during the closing process is equivalent to the dial rotation center, and the equivalent total load torque function T_load(α) for the entire closing stroke is established, where α is the absolute rotation angle of the dial. Based on the initial current setting I_test, determine the current linear thrust F_test of the drive nut; Based on the total load torque function T_load(α) and the current linear thrust F_test, determine the current envelope function (X(α), Y(α)) of the drive slot; The target envelope function of the driving slot is determined based on the current envelope function (X(α), Y(α)).

[0006] By adopting the above technical solution, a design process is established that involves creating an equivalent total load torque function, determining the current linear thrust, solving the current envelope function in reverse, and evaluating and determining the target envelope function. This allows the profile of the dial drive groove to no longer be a fixed geometric shape determined by experience, but rather an adaptive curve generated in reverse based on the resistance characteristics of the entire closing stroke and the actual driving capability of the motor. The resulting drive groove profile has a larger transmission ratio in the resistance peak section at the end of the closing stroke to amplify the lever effect, and a smaller transmission ratio in the middle section before closing stroke where the resistance is relatively flat to increase the movement speed. This effectively smooths out the peaks and valleys of the motor's equivalent output torque, which helps the mechanism smoothly cross the resistance dead point at the end of the closing stroke without increasing the motor's rated power. This improves the motor's utilization efficiency, reduces the risk of motor overheating and overload, and also helps avoid equipment volume redundancy and increased manufacturing costs caused by excessive selection of high-power motors.

[0007] Optionally, the step of determining the target envelope function of the driving slot based on the current envelope function (X(α), Y(α)) includes: The current profile of the driving slot is evaluated based on the current envelope function (X(α), Y(α)). Based on the evaluation results, the target envelope function of the drive slot is determined.

[0008] By adopting the above technical solution, after solving the current envelope function, an evaluation step is added and the target envelope function is determined based on the evaluation results. This enables the design method to have self-verification capabilities. It helps to avoid directly using drive groove profiles with excessive geometric dimensions or poor kinematic characteristics for processing and manufacturing, which is beneficial to improving the reliability and feasibility of the designed dial drive groove in practical applications. It also helps to eliminate potential risks of mechanism jamming or self-locking during the design stage.

[0009] Optionally, the step of determining the target envelope function of the driving slot based on the evaluation results includes: When the evaluation result is satisfactory, the current envelope function (X(α), Y(α)) is taken as the target envelope function; If the evaluation result is unqualified, the initial set current is increased by a preset current step size, and then the process returns to the step of determining the current linear thrust F_test of the drive nut.

[0010] By adopting the above technical solution, the iterative mechanism of increasing the current step size by a preset amount and returning to the solution when the evaluation fails can enable the design method to automatically find the target envelope function that satisfies both geometric and kinematic constraints and minimizes the motor setting current. This is beneficial for keeping the motor operating at a lower current level while meeting the feasibility constraints of the drive slot, which helps improve motor efficiency and reduce heat generation. It also helps reduce the demand on the rated power of the motor, thereby helping to achieve the design goal of cost reduction and efficiency improvement.

[0011] Optionally, the step of evaluating the current profile of the driving slot based on the current envelope function (X(α), Y(α)) includes: Based on the current envelope function (X(α), Y(α)) of the drive groove, determine the current maximum radius and the current maximum pressure angle of the drive groove; Based on the current maximum radius and current maximum pressure angle of the drive groove, determine whether the evaluation result is qualified.

[0012] By adopting the above technical solution, the current maximum radius and current maximum pressure angle of the drive groove profile corresponding to the current envelope function are used as evaluation indicators, providing a clear quantitative basis for the evaluation process. Specifically, constraining the spatial extension range of the drive groove with the maximum radius helps ensure the compactness and installability of the dial, while constraining the force transmission efficiency of the contact pair with the maximum pressure angle helps prevent self-locking or jamming in the high transmission ratio range. This, in turn, helps ensure the feasibility and reliability of the designed drive groove profile in practical applications from both geometric and kinematic perspectives.

[0013] Optionally, the step of determining whether the evaluation result is qualified based on the current maximum radius and current maximum pressure angle of the drive groove includes: The evaluation result is qualified when the current maximum radius is not greater than the preset radius upper limit R_limit and the current maximum pressure angle is not greater than the preset pressure angle upper limit γ_limit; If the current maximum radius is greater than the preset radius limit R_limit, or the current maximum pressure angle is greater than the preset pressure angle limit γ_limit, then the evaluation result is unqualified.

[0014] By adopting the above technical solution, setting a preset upper limit for the radius and a preset upper limit for the pressure angle as constraints for passing the evaluation, and using the judgment logic that both must be met simultaneously for the evaluation to be considered qualified, and either unmet requirement results in disqualification, the evaluation process has clear and strict judgment criteria. This helps ensure that the drive groove profile corresponding to the final determined target envelope function meets the requirements in both geometric space and kinematic characteristics. It also helps avoid overlooking potential design defects due to evaluation based on a single index, thereby improving the reliability and safety of the designed dial drive groove in practical engineering applications.

[0015] Optionally, the step of determining the current envelope function (X(α), Y(α)) of the drive slot based on the total load torque function T_load(α) and the current linear thrust F_test includes: Based on the total load torque function T_load(α) and the current linear thrust F_test, determine the transmission ratio function i(α); Based on the transmission ratio function i(α), determine the absolute pushing displacement function S(α) of the drive nut; The current envelope function (X(α), Y(α)) of the drive groove is determined based on the absolute push displacement function S(α) of the drive nut.

[0016] By adopting the above technical solution, the process of determining the current envelope function is decomposed into three sub-steps: transmission ratio calculation, displacement integration, and coordinate rotation transformation, establishing a complete analytical mapping path from load torque to the solid profile of the drive groove. The inverse calculation of the transmission ratio allows the drive groove profile to adaptively match the nonlinear resistance characteristics of the entire closing stroke, automatically forming a larger transmission ratio in the resistance peak section to amplify the lever effect, and automatically forming a smaller transmission ratio in the resistance flat section to increase the motion speed. The introduction of the kinematic inversion method allows the solution results in the mechanical domain to be directly converted into solid profile coordinates that can be used for machining, helping to shorten the conversion link between design calculation and actual manufacturing, and improving the engineering practicality of the design method.

[0017] Optionally, the step of determining the current linear thrust F_test of the drive nut based on the initial set current includes: The output torque of the motor is determined based on the initial set current I_test; The current linear thrust F_test of the drive nut is determined based on the output torque of the motor.

[0018] By adopting the above technical solution, the mapping function of current and torque is fitted to the actual measured data of the motor bench, and the current linear thrust of the drive nut is obtained by conversion through the transmission chain. This makes the input parameters of the design method come from the actual output characteristics of the motor rather than theoretical estimates, which helps to improve the accuracy of the subsequent reverse solution of the transmission ratio. It also helps to better match the designed drive groove profile with the actual driving capability of the motor, thereby helping to improve the reliability of the design results in practical applications and reduce the mechanism jamming or waste of margin caused by the discrepancy between the actual output of the motor and the design assumptions.

[0019] Optionally, before the step of determining the current linear thrust F_test of the drive nut based on the initial set current, the following steps are included: The initial set current is determined based on the motor's current efficiency curve.

[0020] By adopting the above technical solution, the initial setting current is determined based on the motor's current efficiency curve, providing a clear physical basis and optimization guidance for selecting the starting operating point of the design method. Starting with a smaller current value in the high-efficiency range helps the final design result tend towards a working state with higher motor efficiency and less heat generation, which is beneficial for improving the overall energy efficiency performance of the motor throughout the entire closing stroke. It also helps reduce the requirements for the motor's rated power and heat dissipation capacity, thereby facilitating the miniaturization and cost reduction of the operating mechanism.

[0021] Secondly, the disconnect switch dial provided in this application adopts the following technical solution: A disconnect switch dial is provided with a drive groove, the contour curve of which is a nonlinear envelope, so that the disconnect switch dial can adaptively adjust the transmission ratio to match the nonlinear load resistance during the closing process.

[0022] Thirdly, the disconnector operating mechanism provided in this application adopts the following technical solution: A disconnector switch operating mechanism includes: a motor; a transmission structure including a transmission screw and a drive nut, wherein the transmission screw is driven to the output shaft of the motor via a transmission gear set, and the drive nut is sleeved on the transmission screw; and a dial, including the disconnector switch dial, wherein the drive nut is connected to the drive groove of the dial via a washer.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. By establishing the equivalent total load torque function for the entire closing stroke, and using the linear thrust of the drive nut corresponding to the initial set current of the motor as input, the envelope function of the drive groove is solved in reverse, and the target envelope function is determined through evaluation. This allows the profile of the dial drive groove to be determined by an adaptive curve generated in reverse based on the actual resistance characteristics of the entire closing stroke and the actual driving capability of the motor, rather than a fixed geometric shape determined by experience. The resulting drive groove profile has a larger transmission ratio in the resistance peak section at the end of the closing stroke to amplify the lever effect, and a smaller transmission ratio in the resistance flat section before closing to increase the movement speed. This has a peak-shaving and valley-filling effect on the equivalent output torque of the motor, which helps the mechanism to smoothly cross the resistance dead point at the end of the closing stroke without increasing the rated power of the motor. This is beneficial for improving the utilization efficiency of the motor, reducing the risk of motor overheating and overload, and also helps to avoid equipment volume redundancy and increased manufacturing costs caused by excessive selection of high-power motors. 2. By adding an evaluation step after solving the current envelope function, with the current maximum radius and current maximum pressure angle as evaluation indicators, and an iterative mechanism that increases the initial set current by a preset current step size and returns to the solution again when the evaluation fails, the design method can automatically find the target envelope function that satisfies both geometric and kinematic constraints and minimizes the motor set current. This is beneficial for the motor to operate at a lower current level with higher efficiency and less heat generation while meeting the feasibility constraints of the drive slot. It also helps to eliminate potential risks of mechanism jamming or self-locking during the design stage, thereby improving the reliability and safety of the designed dial drive slot in actual engineering applications. 3. By fitting the mapping function between current and torque based on the actual measured data of the motor bench, and determining the initial set current from the smaller current value in the high-efficiency range according to the current efficiency curve of the motor before executing the design process, the input parameters of the design method are derived from the actual output characteristics of the motor. The selection of the starting operating point has a clear physical basis and optimization guidance, which helps to improve the accuracy of the reverse solution of the transmission ratio, helps to better match the designed drive slot profile with the actual driving capability of the motor, and helps to make the final design result tend to the working state with better overall energy efficiency of the motor. It also helps to reduce the requirements for the rated power and heat dissipation capacity of the motor, thereby facilitating the miniaturization and cost reduction of the operating mechanism. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an embodiment of the disconnector operating mechanism provided in this application; Figure 2 yes Figure 1 A schematic diagram of the calculation for the center dial; Figure 3This is a flowchart illustrating the first embodiment of the disconnect switch dial drive slot contour design method provided in this application; Figure 4 This application provides a current-torque mapping curve for the motor; Figure 5 This is an optimized schematic diagram of the dial drive slot; Figure 6 Schematic diagram showing the output torque of the motors before and after optimizing the dial drive slot; Figure 7 A schematic diagram showing the output power of the motor before and after optimizing the dial drive slot.

[0025] Explanation of reference numerals in the attached figures: 100. Disconnect switch operating mechanism; 11. Transmission screw; 12. Drive nut; 13. Transmission gear set; 14. Washer; 2. Dial; 21. Drive slot. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1 - Appendix Figure 7 This application will be described in further detail below.

[0027] In one embodiment of this application, please refer to Figure 1 and Figure 2 The disconnect switch operating mechanism 100 includes a motor, a transmission structure and a dial 2. The transmission structure includes a transmission screw 11 and a drive nut 12. The transmission screw 11 is driven and connected to the output shaft of the motor through a transmission gear set 13. The drive nut 12 is sleeved on the transmission screw 11 and is connected to the drive groove 21 of the dial 2 through a washer 14.

[0028] It should be noted that the motor is the power source for the disconnector operating mechanism 100, used to output rotary motion and drive torque. The motor can be a series-wound motor suitable for both AC and DC, or other types of drive motors. A transmission gear set 13 is disposed between the motor's output shaft and the transmission screw 11, used to transmit the rotary motion of the motor's output shaft to the transmission screw 11 after reduction and torque amplification. The transmission gear set 13 may include a meshing driving gear and a driven gear. The driving gear is driven and connected to the motor's output shaft, and the driven gear is fixedly connected to or integrally formed with the transmission screw 11. The transmission screw 11 is a rod with external threads, used to convert rotary motion into linear motion of the drive nut 12. The thread of the transmission screw 11 can be a trapezoidal thread or other suitable thread form. The drive nut 12 is an internally threaded component sleeved on the transmission screw 11, forming a helical pair with the external thread of the transmission screw 11. When the transmission screw 11 rotates, the drive nut 12 moves linearly along the axial direction of the transmission screw 11. A sleeve 14 is mounted on the drive nut 12 to form a contact pair with the drive groove 21 of the dial 2. The sleeve 14 can be circular, and its outer contour forms a sliding or rolling contact with the inner wall of the drive groove 21. The dial 2 is a disc-shaped component that can rotate around its center of rotation. The dial 2 has a drive groove 21, which is a slot structure extending radially or approximately radially along the dial 2. The contour shape of the drive groove 21 determines the transmission ratio between the linear motion of the drive nut 12 and the rotational motion of the dial 2. The center of rotation of the dial 2 is connected to the output shaft of the disconnector switch. When the dial 2 rotates, it drives the output shaft to rotate synchronously to complete the closing or opening action.

[0029] It should also be noted that the rotational motion output by the motor is sequentially reduced and amplified by the transmission gear set 13, and the rotational motion is converted into the horizontal linear motion of the drive nut 12 by the transmission screw 11. The drive nut 12 then pushes the dial 2 to rotate around the rotation center along the contour of the drive groove 21 of the dial 2 through the washer 14 on it, thereby driving the output shaft to complete the closing action. Since the contour of the drive groove 21 is generated in reverse according to the resistance characteristics of the entire closing stroke and the driving capacity of the motor, during the closing process, when the mechanism runs to the end resistance peak section, the drive groove 21 adaptively provides a larger transmission ratio to amplify the lever effect, so that the equivalent reverse load felt by the motor end remains at a relatively gentle level, thereby enabling the motor to smoothly drive the mechanism to cross the resistance dead point to complete the closing without overload. Compared with the existing operating mechanism using a fixed groove dial 2, the operating mechanism of this application embodiment can select a smaller power motor under the same closing load conditions, or obtain a larger closing margin under the condition of the same power motor. Further, please refer to Figures 5 to 7After optimization, the shape of the drive groove of dial 2 changes, and the output torque of the optimized motor has the effect of peak shaving and valley filling compared with the original output torque. This not only improves the utilization efficiency of the motor, but also reduces the burden on the motor and improves the reliability of the disconnect switch closing.

[0030] In this embodiment, by combining the variable transmission ratio dial 2 with the motor and transmission structure to form a complete operating mechanism, the variable transmission ratio drive slot 21 has a peak-shaving and valley-filling effect on the equivalent output torque of the motor. This helps improve the load uniformity of the motor throughout the entire closing stroke, reduces the peak torque requirement of the motor, allows for the use of a smaller power motor, and helps reduce the overall size of the operating mechanism and manufacturing costs. Simultaneously, the motor's operation under more uniform load conditions also helps improve its efficiency and reduce heat generation, thus extending the motor's service life and improving the long-term operational reliability of the operating mechanism. Based on the above hardware structure, this application also provides a method for designing the contour of the drive slot 21 of the disconnect switch dial 2, wherein, Figure 3 This is a flowchart illustrating the first embodiment of the design method for the contour of the disconnect switch dial 2 drive slot 21 provided in this application.

[0031] Please see Figure 3 The contour design method for the drive groove 21 of the disconnect switch dial 2 includes: S10. Based on the initial spatial arrangement parameters of the dial rotation center and the transmission structure, the resistance of the disconnecting switch during the closing process is equivalent to the rotation center of the dial 2, and the equivalent total load torque function T_load(α) for the entire closing stroke is established, where α is the absolute rotation angle of the dial 2. It should be noted that the equivalent total load torque function T_load(α) refers to the torque function about the absolute rotation angle α of the dial 2, obtained by uniformly and equivalently converting the resistance encountered by each part of the disconnecting switch during the closing process to the rotation center of the dial 2. The absolute rotation angle α refers to the cumulative angle traversed by the dial 2 from the initial closing position. This equivalent conversion process is based on the geometric dimensions of the drive slot 21, converting various resistance components such as the frictional resistance of the contact finger spring, the contact pressure of the arc contact, and the elastic deformation resistance of the self-force contact during the closing process to the rotation center of the dial 2 according to the torque balance relationship and then superimposing them.

[0032] S20. Determine the current linear thrust F_test of the drive nut 12 based on the initial set current I_test. It should be noted that the initial setting current I_test refers to a pre-set operating current value for the motor, which is used as an input parameter for subsequent calculation of the linear thrust of the drive nut 12. The current linear thrust F_test refers to the horizontal thrust that the drive nut 12 can provide along the axial direction of the transmission screw 11 after being converted by the transmission ratio and transmission efficiency of the transmission gear set 13 and the transmission screw 11 under the motor output torque conditions corresponding to the initial setting current I_test.

[0033] S30. Determine the current envelope function (X(α), Y(α)) of the drive slot 21 based on the total load torque function T_load(α) and the current linear thrust F_test; It should be noted that the current envelope function (X(α), Y(α)) refers to the coordinate function of each point on the profile of the drive groove 21 of the dial 2 obtained by reverse solving according to the total load torque function T_load(α) under the current linear thrust F_test condition. X(α) and Y(α) are the x and y coordinates of the point on the profile of the drive groove 21 corresponding to the rotation angle α of the dial 2 in the rectangular coordinate system with the rotation center of the dial 2 as the origin.

[0034] S40. Determine the target envelope function of the drive slot 21 based on the current envelope function (X(α), Y(α)).

[0035] In this embodiment, firstly, an equivalent total load torque function T_load(α) for the entire closing stroke is established. This function fully describes the variation law of the equivalent resistance torque borne by the dial 2 with the rotation angle during the entire process from the starting position to the closing end position, including the smooth section in the middle section before closing and the resistance peak section at the end. Then, using the initial set current I_test as input, the current linear thrust F_test that the drive nut 12 can provide is determined through motor characteristic mapping and transmission chain calculation. This thrust represents the driving capability that the motor can output through the transmission chain under the set current. Next, the total load torque function T_load(α) is combined with the current linear thrust F_test to solve in reverse the contour coordinates of the drive groove 21 that can balance the corresponding load torque at each rotation angle position, i.e., the current envelope function (X(α), Y(α)). In this reverse solution process, when the load torque at a certain corner position is large, the solved drive groove 21 profile will adaptively form a larger transmission ratio at that location to amplify the mechanical lever effect; when the load torque at a certain corner position is small, the solved profile will form a smaller transmission ratio at that location. Finally, the current envelope function is evaluated to determine whether it meets the preset constraints, thereby determining the final target envelope function. Thus, by establishing the equivalent total load torque function, determining the current linear thrust, reversing the current envelope function, and evaluating and determining the target envelope function, the design process ensures that the profile of the dial 2 drive groove 21 is no longer a fixed geometric shape determined by experience, but rather an adaptive curve generated in reverse based on the resistance characteristics of the entire closing stroke and the actual driving capability of the motor. The resulting drive groove 21 profile has a larger transmission ratio in the peak resistance section at the end of closing to amplify the lever effect, and a smaller transmission ratio in the middle section before closing where the resistance is gentle to increase the movement speed. This has the effect of smoothing out the peaks and filling the valleys of the motor's equivalent output torque. This helps the mechanism to smoothly cross the resistance dead point at the end of closing without increasing the motor's rated power, which is beneficial to improving the utilization efficiency of the motor, reducing the risk of motor overheating and overload, and also helps to avoid the equipment volume redundancy and increased manufacturing costs caused by excessive selection of high-power motors. In one embodiment of this application, step S40 of determining the target envelope function of the drive slot 21 includes: S41. Evaluate the current profile of the drive slot 21 based on the current envelope function (X(α), Y(α)) of the drive slot 21. It should be noted that evaluation refers to the process of verifying the feasibility of the contour of the driving groove 21 corresponding to the current envelope function (X(α), Y(α)) obtained by the solution, in order to determine whether the contour meets the requirements. The object of evaluation is the current contour of the driving groove 21, the basis of the evaluation is the preset constraints, and the evaluation result is qualified or unqualified. When the evaluation result is qualified, it indicates that the contour of the driving groove 21 corresponding to the current envelope function meets the requirements and can be used as the final target envelope function to guide the machining. When the evaluation result is unqualified, it indicates that the contour of the driving groove 21 corresponding to the current envelope function exceeds the preset constraint range in one or more aspects, and it is necessary to adjust the input parameters and solve it again.

[0036] S42. Based on the evaluation results, determine the target envelope function of the drive slot 21.

[0037] In this embodiment, after obtaining the current envelope function, it is not directly used as the final target envelope function. Instead, it is evaluated to verify its feasibility. This is because during the reverse solution process, in order to balance the large load torque under a small motor thrust, the solved drive groove 21 profile may have an excessively large transmission ratio in some local sections. An excessively large transmission ratio means that the extension direction of the drive groove 21 at that point tends to be horizontal. This may cause the radial dimension of the drive groove 21 to exceed the available space of the dial 2, or cause the pressure angle at the contact point between the pad 14 and the drive groove 21 to be too large, resulting in an insufficient effective thrust component or even triggering self-locking. Therefore, by evaluating and verifying the current profile, infeasible profile schemes can be identified and eliminated in time during the design phase, so that the final determined target envelope function can achieve the peak-shaving and valley-filling transmission ratio distribution effect. Thus, by adding an evaluation step after solving the current envelope function and determining the target envelope function based on the evaluation results, the design method has self-verification capability. This helps to avoid directly using the profile of the drive groove 21 with out-of-limit geometric dimensions or poor kinematic characteristics for processing and manufacturing, which is beneficial to improving the reliability and feasibility of the designed dial 2 drive groove 21 in practical applications. It also helps to eliminate potential risks of mechanism jamming or self-locking during the design stage.

[0038] In one embodiment of this application, step S42 includes: S421. When the evaluation result is qualified, the current envelope function (X(α), Y(α)) is taken as the target envelope function; S422. When the evaluation result is unqualified, the initial set current is increased by a preset current step size, and then the process returns to the step of determining the current linear thrust F_test of the drive nut 12.

[0039] It should be noted that the preset current step size refers to the incremental value used to adjust the initial set current I_test when the evaluation result is unqualified. This current step size can be set according to the rated current of the motor and the design accuracy requirements, for example, it can be set to one percent to five percent of the rated current of the motor. Returning to the step of determining the current linear thrust F_test of the drive nut 12 means taking the new set current after increasing the current step size as the updated initial set current, re-executing step S20 to determine the new current linear thrust, then resolving the new current envelope function, and then re-evaluating the new current envelope function. This iterative process continues until the evaluation result is qualified. When the evaluation result is qualified, the current envelope function at this time is determined as the target envelope function, which is the contour coordinate function ultimately used to guide the machining of the drive groove 21 of the dial 2.

[0040] In this embodiment, when the profile evaluation of the drive slot 21 corresponding to a certain set current fails, it indicates that the thrust provided by the motor at that current is too small, and the transmission ratio required to balance the load torque is too large, causing the geometric dimensions or pressure angle of the drive slot 21 profile to exceed the constraint range in a local section. At this time, by increasing a preset current step size to moderately increase the set current of the motor, the motor can provide greater thrust, thereby reducing the required transmission ratio during reverse solving. The extension trend of the drive slot 21 profile becomes more reasonable, and the geometric dimensions and pressure angle also decrease accordingly. Since there is a monotonically increasing relationship between the increase of the set current and the decrease of the transmission ratio and pressure angle, this iterative process is convergent and can find the set current and its corresponding target envelope function that satisfy the constraint conditions after a finite number of iterations. Simultaneously, since the iteration starts with a smaller current and gradually increases, the final converged set current is a smaller current value that satisfies the constraint conditions, which helps the motor operate at the lowest possible current level. Thus, by using an iterative mechanism that increments the current step size by a preset current step size and returns to the solution when the evaluation fails, the design method can automatically find the target envelope function that satisfies both geometric and kinematic constraints and minimizes the motor's set current. This is beneficial for keeping the motor operating at a lower current level while meeting the feasibility constraints of drive slot 21, which helps improve motor efficiency and reduce heat generation. It also helps reduce the demand on the motor's rated power, thereby helping to achieve the design goal of cost reduction and efficiency improvement.

[0041] In one embodiment of this application, step S41 includes: S411. Determine the current maximum radius and current maximum pressure angle of the drive groove 21 based on the current envelope function (X(α), Y(α)) of the drive groove 21. It should be noted that the current maximum radius refers to the maximum distance from each point on the drive groove 21 profile described by the current envelope function (X(α), Y(α)) to the rotation center of the dial 2. The current radius function R(α) is calculated as the square root of the sum of the squares of X(α) and Y(α), that is, the current maximum radius is the maximum value of R(α) over the entire stroke range of the absolute rotation angle α of the dial 2. The current maximum pressure angle refers to the maximum angle between the direction of the normal force at the contact point between the pad 14 and the drive groove 21 on the drive groove 21 profile described by the current envelope function and the direction of movement of the drive nut 12. The current pressure angle function γ(α) is calculated as follows: H is the vertical offset from the horizontal thrust axis of the transmission screw 11 to the rotation center of the dial 2, X0 is the absolute abscissa of the starting point of the drive nut 12, and S(α) is the absolute thrust displacement function of the drive nut 12. The current maximum pressure angle is the maximum value of γ(α) within the entire stroke range of the absolute rotation angle α of the dial 2. The pressure angle reflects the proportional relationship between the effective component and the friction loss component in the thrust applied by the bushing 14 to the drive groove 21. The larger the pressure angle, the smaller the effective thrust component and the greater the friction loss.

[0042] S412. Based on the current maximum radius and current maximum pressure angle of the drive groove 21, determine whether the evaluation result is qualified.

[0043] In this embodiment, the current maximum radius reflects the maximum radial extension range of the drive groove 21 profile. If this value is too large, the drive groove 21 will exceed the available disk space of the dial 2, resulting in the dial 2 being too large to be installed in the housing of the operating mechanism. The current maximum pressure angle reflects the force transmission efficiency of the contact pair between the pad 14 and the drive groove 21 at the most unfavorable position. If this value is too large, the component of the thrust applied by the pad 14 used to overcome friction will be greater than the effective component used to drive the dial 2 to rotate. When the pressure angle exceeds the self-locking angle, the mechanism will be unable to move. Therefore, by evaluating the maximum values ​​of these two indicators simultaneously, the geometric and kinematic feasibility of the drive groove 21 profile under the most unfavorable working conditions can be comprehensively examined. Thus, using the current maximum radius and current maximum pressure angle of the drive groove 21 profile corresponding to the current envelope function as evaluation indicators provides a clear quantitative basis for the evaluation process. Among them, constraining the spatial extension range of the drive groove 21 with the maximum radius helps to ensure the compactness and installability of the dial 2, and constraining the force transmission efficiency of the contact pair with the maximum pressure angle helps to avoid self-locking or jamming of the mechanism in the high transmission ratio section. This is conducive to ensuring the feasibility and reliability of the designed drive groove 21 profile in practical applications from both geometric and kinematic perspectives.

[0044] In one embodiment of this application, step S412 includes: S4121. When the current maximum radius is not greater than the preset radius upper limit R_limit and the current maximum pressure angle is not greater than the preset pressure angle upper limit γ_limit, the evaluation result is qualified. S4122. When the current maximum radius is greater than the preset radius upper limit R_limit, or the current maximum pressure angle is greater than the preset pressure angle upper limit γ_limit, the evaluation result is unqualified.

[0045] It should be noted that the preset radius upper limit R_limit refers to the maximum allowable radial extension range of the drive groove 21, which is predetermined based on the actual usable disk space of the dial 2 and the installation dimensions of the operating mechanism housing. The preset pressure angle upper limit γ_limit refers to the maximum allowable pressure angle, which is predetermined based on the friction characteristics of the contact pair between the pad 14 and the drive groove 21. This value needs to be set to ensure that the contact pair will not self-lock at this pressure angle. It can usually be obtained by determining the self-locking critical angle based on the friction coefficient μ of the contact pair and leaving a safety margin. The condition for a qualified evaluation result is that the current maximum radius and the current maximum pressure angle simultaneously meet their respective constraint upper limits, that is, both conditions must be met simultaneously; the condition for a failed evaluation result is that either the current maximum radius or the current maximum pressure angle exceeds its constraint upper limit, that is, if either condition is not met, it is judged as unqualified.

[0046] In this embodiment, the evaluation criteria for passing the assessment are set to simultaneously satisfy two conditions: the current maximum radius is not greater than a preset upper limit for the radius, and the current maximum pressure angle is not greater than a preset upper limit for the pressure angle. That is, the drive groove 21 profile is considered feasible only when it meets the constraints in both geometric space and kinematic characteristics. Conversely, if either the geometric space constraint or the kinematic constraint is not met, the profile is considered infeasible and requires adjustment of the current setting and re-solution. This assessment method avoids situations where the drive groove 21 profile meets the requirements in radial dimensions but has a self-locking risk in the pressure angle, and also avoids situations where the pressure angle meets the requirements but the radial dimension exceeds the available space of the dial 2. Thus, by setting a preset upper limit for the radius and a preset upper limit for the pressure angle as constraints for passing the evaluation, and adopting a judgment logic that both must be met simultaneously for the evaluation to be considered qualified, and either unmet requirement results in disqualification, the evaluation process has clear and strict judgment criteria. This helps ensure that the profile of the drive groove 21 corresponding to the final determined target envelope function meets the requirements in both geometric space and kinematic characteristics. It also helps avoid overlooking potential design defects due to evaluation based on a single index, thereby improving the reliability and safety of the designed dial 2 drive groove 21 in practical engineering applications.

[0047] In one embodiment of this application, step S30 includes: S31. Determine the transmission ratio function i(α) based on the total load torque function T_load(α) and the current linear thrust F_test; It should be noted that the transmission ratio function i(α) is a function of the ratio of the linear velocity of the driving nut 12 moving horizontally forward to the angular velocity of the dial 2 rotating, as a function of the absolute angle α of the dial 2. It represents the conversion ratio between the linear motion of the driving nut 12 and the rotational motion of the dial 2 at each angular position. The transmission ratio function i(α) is calculated based on the transient torque balance equation T_load(α) = F_test × i(α) × η_dial + T_impact, where η_dial is the transmission efficiency of the contact pair between the drive groove 21 of the dial 2 and the driving nut 12, and T_impact is the inertial torque. The inertial torque T_impact is the auxiliary torque generated by the conversion of kinetic energy when the driving nut 12 impacts the drive groove 21 of the dial 2 after its idle stroke. Under most operating conditions, its value is relatively small compared to the load torque and can be ignored. From the transient torque balance equation, we can obtain i(α)=[T_load(α)−T_impact] / (F_test×η_dial).

[0048] S32. Determine the absolute pushing displacement function S(α) of the drive nut 12 according to the transmission ratio function i(α); It should be noted that the absolute propulsion displacement function S(α) refers to the cumulative displacement of the drive nut 12 moving axially along the transmission screw 11 from the starting position as a function of the absolute rotation angle α of the dial 2. Since the transmission ratio is defined as i(α)=dS / dα, S(α) is the definite integral of the transmission ratio function i(α) on the interval [0,α]. Therefore, the absolute propulsion displacement function S(α) of the drive nut 12 on the transmission screw 11 can be obtained.

[0049] S33. Determine the current envelope function (X(α), Y(α)) of the drive groove 21 based on the absolute push displacement function S(α) of the drive nut 12.

[0050] It should be noted that the current envelope function (X(α), Y(α)) refers to the coordinate function of each point on the contour of the drive groove 21 of the dial 2 in a rectangular coordinate system with the rotation center of the dial 2 as the origin. Please refer to [link / reference needed]. Figure 2Establish a rectangular coordinate system with the rotation center of dial 2 as the origin. Let the vertical offset distance from the horizontal thrust axis of the lead screw to the center of dial 2 be H, and the absolute abscissa of the starting point of the nut be X0. Based on the principle of kinematic relativity, assume that the dial 2 is stationary. Let the instantaneous coordinate displacement point (X0−S(α), H) of the drive nut 12 be rotated in the opposite direction by an angle of -α around the origin. By introducing a two-dimensional polar coordinate rotation matrix, the current envelope function of the drive groove 21 can be determined: X(α)=[X0-S(α)]*cos(α)+H*sin(α), Y(α)=-[X0-S(α)]*sin(α)+H*cos(α).

[0051] In this embodiment, the total load torque function T_load(α) is combined with the current linear thrust F_test according to the transient torque balance equation to solve for the transmission ratio function i(α) in reverse. The physical meaning of this solution process is that, under a given driving thrust, the drive groove 21 should provide a certain transmission ratio to balance the corresponding load torque at each corner position. When the load torque T_load(α) at ​​a certain corner position is large, the solved transmission ratio i(α) increases adaptively while the thrust F_test remains unchanged, meaning that the drive groove 21 needs to provide a greater lever amplification effect at that position. Then, the transmission ratio function is integrated to obtain the absolute thrust displacement function S(α) of the drive nut 12, converting the transmission ratio information in the mechanical domain into displacement information in the kinematic domain. Then, based on the principle of kinematic relativity, assuming the dial 2 is stationary, the instantaneous coordinate displacement point (X0−S(α),H) of the drive nut 12 is rotated in the opposite direction by a negative α angle around the rotation center of the dial 2. A two-dimensional polar coordinate rotation matrix is ​​introduced to convert the displacement information in the kinematic domain into the contour coordinates of the drive groove 21 in the geometric domain, obtaining the current envelope function (X(α),Y(α)). Thus, by decomposing the process of determining the current envelope function into three sub-steps—transmission ratio calculation, displacement integration, and coordinate rotation transformation—a complete analytical mapping path from the load torque to the solid contour of the drive groove 21 is established. The inverse calculation of the transmission ratio allows the contour of the drive groove 21 to adaptively match the nonlinear resistance characteristics of the entire closing stroke, automatically forming a larger transmission ratio in the resistance peak section to amplify the lever effect, and automatically forming a smaller transmission ratio in the resistance flat section to increase the movement speed. The introduction of the kinematic inversion method allows the solution results in the mechanical domain to be directly converted into solid contour coordinates that can be used for machining, helping to shorten the conversion link between design calculation and actual manufacturing, and improving the engineering practicality of the design method.

[0052] In one embodiment of this application, step S20 includes: S21. Determine the output torque of the motor based on the initial set current I_test; It should be noted that the process of measuring the motor output torque T_test is based on actual test data from a motor bench. Specifically, a bench test is first performed on the motor to obtain actual output torque data under different effective current values. Then, the least squares regression method is used to fit an empirical mapping function between the effective current value I and the output torque T. The expression of this mapping function is T_test(I)=a×I³+b×I²+c×I+d, where a, b, c, and d are fitting coefficients, determined from the measured data through least squares regression. Figure 4 As shown, this empirical mapping function establishes a quantitative correspondence between motor current and output torque. Substituting the initial set current I_test into this function determines the motor's output torque T_test at that current. This fitting method can also employ piecewise fitting, for example, using quadratic polynomial fitting in the low current range of motor startup and linear function fitting in the operating current range of deep magnetic circuit saturation.

[0053] S22. Determine the current linear thrust F_test of the drive nut 12 based on the output torque of the motor.

[0054] It should be noted that after determining the motor output torque T_test, it can be converted according to the transmission ratio and transmission efficiency of the transmission gear set 13 and the lead and transmission efficiency of the transmission screw 11 to obtain the current linear thrust F_test that the drive nut 12 can provide along the axial direction of the transmission screw 11.

[0055] In this embodiment, the mapping relationship between current and torque is established by fitting actual test data from a motor test bench, rather than by calculating using theoretical formulas or nameplate parameters of the motor. This is because the motor is affected by various factors such as magnetic circuit saturation, iron loss, and mechanical loss during actual operation, resulting in a deviation between its actual output torque and the theoretically calculated value. Fitting actual test data from a test bench can more accurately reflect the true output characteristics of the motor. After obtaining the motor output torque, it is converted into the linear thrust of the drive nut 12 through the transmission ratio and transmission efficiency of the transmission chain. This allows the subsequent reverse calculation of the transmission ratio to be based on the actual available thrust of the drive nut 12, thereby matching the solved profile of the drive groove 21 with the actual output capability of the motor. Thus, by fitting the mapping function of current and torque based on the actual measured data of the motor test bench, and calculating the current linear thrust of the drive nut 12 through the transmission chain, the input parameters of the design method are derived from the actual output characteristics of the motor rather than theoretical estimates. This helps to improve the accuracy of the subsequent reverse calculation of the transmission ratio, and helps to better match the profile of the designed drive groove 21 with the actual driving capability of the motor. This helps to improve the reliability of the design results in practical applications and reduce mechanism jamming or waste of margin caused by the discrepancy between the actual output of the motor and the design assumptions.

[0056] In one embodiment of this application, before step S20, the following steps are included: S23. Determine the initial set current based on the current efficiency curve of the motor.

[0057] It should be noted that the current efficiency curve refers to the relationship between the overall efficiency of the motor and the change in current under different effective current values. This curve can be obtained through motor bench testing. Overall efficiency refers to the ratio of the motor's mechanical output power to its electrical input power. The overall efficiency of the motor usually shows a trend of first increasing and then decreasing with the change in current, reaching a higher level within a certain current range; this range is the motor's high-efficiency range. The initial setting current refers to a current value selected within this high-efficiency range, used as the starting input parameter to determine the current linear thrust of the drive nut 12. In order to operate the motor at the lowest possible current level to improve efficiency and reduce heat generation while meeting the constraints, the initial setting current should be set starting from a smaller current value within the high-efficiency range, so that it can be gradually increased in subsequent iterations to find a lower current value that meets the constraints.

[0058] In this embodiment, before determining the current linear thrust, an initial set current is determined based on the motor's current efficiency curve. This aims to ensure that subsequent design calculations start from the motor's most efficient operating point. When the motor operates at excessively low current, iron losses and mechanical losses account for a large proportion of the total losses, resulting in low efficiency. Conversely, when operating at excessively high current, copper losses increase dramatically, leading to a similar decrease in efficiency and increased heat generation. Therefore, by selecting a current value within the high-efficiency range as the initial set current, the motor operating point corresponding to the subsequently solved drive slot 21 profile falls within a high-efficiency region. Simultaneously, starting with a smaller current value within the high-efficiency range, coupled with an iterative mechanism that increments the current step size when evaluation fails, ensures that the final converged set current is a lower value within the high-efficiency range that satisfies the constraints. This achieves a better balance between motor efficiency and heat generation while meeting drive requirements. Thus, by determining the initial set current based on the motor's current efficiency curve, the selection of the starting operating point in the design method has a clear physical basis and optimization guidance. Starting with a smaller current value in the high-efficiency range helps to make the final design result tend towards a working state with higher motor efficiency and less heat generation. This is beneficial to improving the overall energy efficiency of the motor throughout the entire closing stroke, and also helps to reduce the requirements for the motor's rated power and heat dissipation capacity, thereby facilitating the miniaturization and cost reduction of the operating mechanism.

[0059] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for designing the contour of a drive groove for a disconnect switch dial, characterized in that, include: Based on the initial spatial arrangement parameters of the dial rotation center and the transmission structure, the resistance of the disconnecting switch during the closing process is equivalent to the dial rotation center, and the equivalent total load torque function T_load(α) for the entire closing stroke is established, where α is the absolute rotation angle of the dial. Based on the initial current setting I_test, determine the current linear thrust F_test of the drive nut; Based on the total load torque function T_load(α) and the current linear thrust F_test, determine the current envelope function (X(α), Y(α)) of the drive slot; The target envelope function of the driving slot is determined based on the current envelope function (X(α), Y(α)).

2. The method for designing the contour of the disconnect switch dial drive groove according to claim 1, characterized in that, The step of determining the target envelope function of the driving slot based on the current envelope function (X(α), Y(α)) includes: The current profile of the driving slot is evaluated based on the current envelope function (X(α), Y(α)). Based on the evaluation results, the target envelope function of the drive slot is determined.

3. The method for designing the contour of the disconnect switch dial drive groove according to claim 2, characterized in that, The step of determining the target envelope function of the drive slot based on the evaluation results includes: When the evaluation result is satisfactory, the current envelope function (X(α), Y(α)) is taken as the target envelope function; If the evaluation result is unqualified, the initial set current is increased by a preset current step size, and then the process returns to the step of determining the current linear thrust F_test of the drive nut.

4. The method for designing the contour of the disconnect switch dial drive groove according to claim 2, characterized in that, The step of evaluating the current profile of the driving slot based on the current envelope function (X(α), Y(α)) includes: Based on the current envelope function (X(α), Y(α)) of the drive groove, determine the current maximum radius and the current maximum pressure angle of the drive groove; Based on the current maximum radius and current maximum pressure angle of the drive groove, determine whether the evaluation result is qualified.

5. The method for designing the contour of the disconnect switch dial drive groove according to claim 4, characterized in that, The step of determining whether the evaluation result is qualified based on the current maximum radius and current maximum pressure angle of the drive groove includes: The evaluation result is qualified when the current maximum radius is not greater than the preset radius upper limit R_limit and the current maximum pressure angle is not greater than the preset pressure angle upper limit γ_limit; If the current maximum radius is greater than the preset radius limit R_limit, or the current maximum pressure angle is greater than the preset pressure angle limit γ_limit, then the evaluation result is unqualified.

6. The method for designing the contour of the disconnect switch dial drive groove according to claim 1, characterized in that, The step of determining the current envelope function (X(α), Y(α)) of the drive slot based on the total load torque function T_load(α) and the current linear thrust F_test includes: Based on the total load torque function T_load(α) and the current linear thrust F_test, determine the transmission ratio function i(α); Based on the transmission ratio function i(α), determine the absolute pushing displacement function S(α) of the drive nut; The current envelope function (X(α), Y(α)) of the drive groove is determined based on the absolute push displacement function S(α) of the drive nut.

7. The method for designing the contour of the disconnect switch dial drive groove according to claim 1, characterized in that, The step of determining the current linear thrust F_test of the drive nut based on the initial set current includes: The output torque of the motor is determined based on the initial set current I_test; The current linear thrust F_test of the drive nut is determined based on the output torque of the motor.

8. The method for designing the contour of the disconnect switch dial drive groove according to claim 1, characterized in that, Before the step of determining the current linear thrust F_test of the drive nut based on the initial set current, the following steps are included: The initial set current is determined based on the motor's current efficiency curve.

9. A disconnect switch dial, characterized in that, The disconnect switch dial is provided with a drive groove, the contour curve of which is a non-linear envelope, so that the disconnect switch dial can adaptively adjust the transmission ratio to match the non-linear load resistance during the closing process.

10. A disconnector switch operating mechanism, characterized in that, include: Electric motor; A transmission structure includes a lead screw and a drive nut, wherein the lead screw is drivenly connected to the output shaft of the motor via a transmission gear set, and the drive nut is sleeved on the lead screw; and... According to claim 9, the drive nut is connected to the drive groove of the dial via a washer.

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